From 61ea0c0ba904a55f55317d850c1072ff7835ac92 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:13 +0100 Subject: KEYS: Skip key state checks when checking for possession Skip key state checks (invalidation, revocation and expiration) when checking for possession. Without this, keys that have been marked invalid, revoked keys and expired keys are not given a possession attribute - which means the possessor is not granted any possession permits and cannot do anything with them unless they also have one a user, group or other permit. This causes failures in the keyutils test suite's revocation and expiration tests now that commit 96b5c8fea6c0861621051290d705ec2e971963f1 reduced the initial permissions granted to a key. The failures are due to accesses to revoked and expired keys being given EACCES instead of EKEYREVOKED or EKEYEXPIRED. Signed-off-by: David Howells --- security/keys/internal.h | 1 + security/keys/process_keys.c | 8 +++++--- security/keys/request_key.c | 6 ++++-- security/keys/request_key_auth.c | 2 +- 4 files changed, 11 insertions(+), 6 deletions(-) (limited to 'security/keys') diff --git a/security/keys/internal.h b/security/keys/internal.h index d4f1468b9b5..df971feceaf 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -124,6 +124,7 @@ extern key_ref_t search_my_process_keyrings(struct key_type *type, extern key_ref_t search_process_keyrings(struct key_type *type, const void *description, key_match_func_t match, + bool no_state_check, const struct cred *cred); extern struct key *find_keyring_by_name(const char *name, bool skip_perm_check); diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c index 42defae1e16..a3410d60584 100644 --- a/security/keys/process_keys.c +++ b/security/keys/process_keys.c @@ -440,6 +440,7 @@ found: key_ref_t search_process_keyrings(struct key_type *type, const void *description, key_match_func_t match, + bool no_state_check, const struct cred *cred) { struct request_key_auth *rka; @@ -448,7 +449,7 @@ key_ref_t search_process_keyrings(struct key_type *type, might_sleep(); key_ref = search_my_process_keyrings(type, description, match, - false, cred); + no_state_check, cred); if (!IS_ERR(key_ref)) goto found; err = key_ref; @@ -468,7 +469,8 @@ key_ref_t search_process_keyrings(struct key_type *type, rka = cred->request_key_auth->payload.data; key_ref = search_process_keyrings(type, description, - match, rka->cred); + match, no_state_check, + rka->cred); up_read(&cred->request_key_auth->sem); @@ -675,7 +677,7 @@ try_again: /* check to see if we possess the key */ skey_ref = search_process_keyrings(key->type, key, lookup_user_key_possessed, - cred); + true, cred); if (!IS_ERR(skey_ref)) { key_put(key); diff --git a/security/keys/request_key.c b/security/keys/request_key.c index c411f9bb156..172115b3805 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -390,7 +390,8 @@ static int construct_alloc_key(struct key_type *type, * waited for locks */ mutex_lock(&key_construction_mutex); - key_ref = search_process_keyrings(type, description, type->match, cred); + key_ref = search_process_keyrings(type, description, type->match, + false, cred); if (!IS_ERR(key_ref)) goto key_already_present; @@ -539,7 +540,8 @@ struct key *request_key_and_link(struct key_type *type, dest_keyring, flags); /* search all the process keyrings for a key */ - key_ref = search_process_keyrings(type, description, type->match, cred); + key_ref = search_process_keyrings(type, description, type->match, + false, cred); if (!IS_ERR(key_ref)) { key = key_ref_to_ptr(key_ref); diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c index 85730d5a5a5..92077de555d 100644 --- a/security/keys/request_key_auth.c +++ b/security/keys/request_key_auth.c @@ -247,7 +247,7 @@ struct key *key_get_instantiation_authkey(key_serial_t target_id) &key_type_request_key_auth, (void *) (unsigned long) target_id, key_get_instantiation_authkey_match, - cred); + false, cred); if (IS_ERR(authkey_ref)) { authkey = ERR_CAST(authkey_ref); -- cgit v1.2.3-70-g09d2 From a5b4bd2874d9032b42db8cc4880058576c561b06 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:14 +0100 Subject: KEYS: Use bool in make_key_ref() and is_key_possessed() Make make_key_ref() take a bool possession parameter and make is_key_possessed() return a bool. Signed-off-by: David Howells --- Documentation/security/keys.txt | 7 +++---- include/linux/key.h | 4 ++-- security/keys/keyring.c | 5 +++-- 3 files changed, 8 insertions(+), 8 deletions(-) (limited to 'security/keys') diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt index 7b4145d0045..9ede67084f0 100644 --- a/Documentation/security/keys.txt +++ b/Documentation/security/keys.txt @@ -865,15 +865,14 @@ encountered: calling processes has a searchable link to the key from one of its keyrings. There are three functions for dealing with these: - key_ref_t make_key_ref(const struct key *key, - unsigned long possession); + key_ref_t make_key_ref(const struct key *key, bool possession); struct key *key_ref_to_ptr(const key_ref_t key_ref); - unsigned long is_key_possessed(const key_ref_t key_ref); + bool is_key_possessed(const key_ref_t key_ref); The first function constructs a key reference from a key pointer and - possession information (which must be 0 or 1 and not any other value). + possession information (which must be true or false). The second function retrieves the key pointer from a reference and the third retrieves the possession flag. diff --git a/include/linux/key.h b/include/linux/key.h index 4dfde1161c5..51bce2950de 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -99,7 +99,7 @@ struct keyring_name; typedef struct __key_reference_with_attributes *key_ref_t; static inline key_ref_t make_key_ref(const struct key *key, - unsigned long possession) + bool possession) { return (key_ref_t) ((unsigned long) key | possession); } @@ -109,7 +109,7 @@ static inline struct key *key_ref_to_ptr(const key_ref_t key_ref) return (struct key *) ((unsigned long) key_ref & ~1UL); } -static inline unsigned long is_key_possessed(const key_ref_t key_ref) +static inline bool is_key_possessed(const key_ref_t key_ref) { return (unsigned long) key_ref & 1UL; } diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 6ece7f2e570..f78406372eb 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -329,9 +329,10 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref, struct keyring_list *keylist; struct timespec now; - unsigned long possessed, kflags; + unsigned long kflags; struct key *keyring, *key; key_ref_t key_ref; + bool possessed; long err; int sp, nkeys, kix; @@ -542,8 +543,8 @@ key_ref_t __keyring_search_one(key_ref_t keyring_ref, key_perm_t perm) { struct keyring_list *klist; - unsigned long possessed; struct key *keyring, *key; + bool possessed; int nkeys, loop; keyring = key_ref_to_ptr(keyring_ref); -- cgit v1.2.3-70-g09d2 From 7e55ca6dcd07b45619035df343c9614a3ab35034 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:14 +0100 Subject: KEYS: key_is_dead() should take a const key pointer argument key_is_dead() should take a const key pointer argument as it doesn't modify what it points to. Signed-off-by: David Howells --- security/keys/internal.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'security/keys') diff --git a/security/keys/internal.h b/security/keys/internal.h index df971feceaf..490aef5ba34 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -203,7 +203,7 @@ extern struct key *key_get_instantiation_authkey(key_serial_t target_id); /* * Determine whether a key is dead. */ -static inline bool key_is_dead(struct key *key, time_t limit) +static inline bool key_is_dead(const struct key *key, time_t limit) { return key->flags & ((1 << KEY_FLAG_DEAD) | -- cgit v1.2.3-70-g09d2 From 16feef4340172b7dbb9cba60850e78fa6388adf1 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:15 +0100 Subject: KEYS: Consolidate the concept of an 'index key' for key access Consolidate the concept of an 'index key' for accessing keys. The index key is the search term needed to find a key directly - basically the key type and the key description. We can add to that the description length. This will be useful when turning a keyring into an associative array rather than just a pointer block. Signed-off-by: David Howells --- include/linux/key.h | 21 +++++++++---- security/keys/internal.h | 8 ++--- security/keys/key.c | 72 +++++++++++++++++++++++---------------------- security/keys/keyring.c | 37 +++++++++++------------ security/keys/request_key.c | 12 +++++--- 5 files changed, 83 insertions(+), 67 deletions(-) (limited to 'security/keys') diff --git a/include/linux/key.h b/include/linux/key.h index 51bce2950de..d573e820a23 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -82,6 +82,12 @@ struct key_owner; struct keyring_list; struct keyring_name; +struct keyring_index_key { + struct key_type *type; + const char *description; + size_t desc_len; +}; + /*****************************************************************************/ /* * key reference with possession attribute handling @@ -129,7 +135,6 @@ struct key { struct list_head graveyard_link; struct rb_node serial_node; }; - struct key_type *type; /* type of key */ struct rw_semaphore sem; /* change vs change sem */ struct key_user *user; /* owner of this key */ void *security; /* security data for this key */ @@ -163,12 +168,18 @@ struct key { #define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */ #define KEY_FLAG_INVALIDATED 7 /* set if key has been invalidated */ - /* the description string - * - this is used to match a key against search criteria - * - this should be a printable string + /* the key type and key description string + * - the desc is used to match a key against search criteria + * - it should be a printable string * - eg: for krb5 AFS, this might be "afs@REDHAT.COM" */ - char *description; + union { + struct keyring_index_key index_key; + struct { + struct key_type *type; /* type of key */ + char *description; + }; + }; /* type specific data * - this is used by the keyring type to index the name diff --git a/security/keys/internal.h b/security/keys/internal.h index 490aef5ba34..77441dd1f9d 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -89,19 +89,17 @@ extern struct key_type *key_type_lookup(const char *type); extern void key_type_put(struct key_type *ktype); extern int __key_link_begin(struct key *keyring, - const struct key_type *type, - const char *description, + const struct keyring_index_key *index_key, unsigned long *_prealloc); extern int __key_link_check_live_key(struct key *keyring, struct key *key); extern void __key_link(struct key *keyring, struct key *key, unsigned long *_prealloc); extern void __key_link_end(struct key *keyring, - struct key_type *type, + const struct keyring_index_key *index_key, unsigned long prealloc); extern key_ref_t __keyring_search_one(key_ref_t keyring_ref, - const struct key_type *type, - const char *description, + const struct keyring_index_key *index_key, key_perm_t perm); extern struct key *keyring_search_instkey(struct key *keyring, diff --git a/security/keys/key.c b/security/keys/key.c index 8fb7c7bd465..7e6bc396bb2 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -242,8 +242,8 @@ struct key *key_alloc(struct key_type *type, const char *desc, } } - desclen = strlen(desc) + 1; - quotalen = desclen + type->def_datalen; + desclen = strlen(desc); + quotalen = desclen + 1 + type->def_datalen; /* get hold of the key tracking for this user */ user = key_user_lookup(uid); @@ -277,7 +277,8 @@ struct key *key_alloc(struct key_type *type, const char *desc, goto no_memory_2; if (desc) { - key->description = kmemdup(desc, desclen, GFP_KERNEL); + key->index_key.desc_len = desclen; + key->index_key.description = kmemdup(desc, desclen + 1, GFP_KERNEL); if (!key->description) goto no_memory_3; } @@ -285,7 +286,7 @@ struct key *key_alloc(struct key_type *type, const char *desc, atomic_set(&key->usage, 1); init_rwsem(&key->sem); lockdep_set_class(&key->sem, &type->lock_class); - key->type = type; + key->index_key.type = type; key->user = user; key->quotalen = quotalen; key->datalen = type->def_datalen; @@ -489,8 +490,7 @@ int key_instantiate_and_link(struct key *key, } if (keyring) { - ret = __key_link_begin(keyring, key->type, key->description, - &prealloc); + ret = __key_link_begin(keyring, &key->index_key, &prealloc); if (ret < 0) goto error_free_preparse; } @@ -499,7 +499,7 @@ int key_instantiate_and_link(struct key *key, &prealloc); if (keyring) - __key_link_end(keyring, key->type, prealloc); + __key_link_end(keyring, &key->index_key, prealloc); error_free_preparse: if (key->type->preparse) @@ -548,8 +548,7 @@ int key_reject_and_link(struct key *key, ret = -EBUSY; if (keyring) - link_ret = __key_link_begin(keyring, key->type, - key->description, &prealloc); + link_ret = __key_link_begin(keyring, &key->index_key, &prealloc); mutex_lock(&key_construction_mutex); @@ -581,7 +580,7 @@ int key_reject_and_link(struct key *key, mutex_unlock(&key_construction_mutex); if (keyring) - __key_link_end(keyring, key->type, prealloc); + __key_link_end(keyring, &key->index_key, prealloc); /* wake up anyone waiting for a key to be constructed */ if (awaken) @@ -780,25 +779,27 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, key_perm_t perm, unsigned long flags) { - unsigned long prealloc; + struct keyring_index_key index_key = { + .description = description, + }; struct key_preparsed_payload prep; const struct cred *cred = current_cred(); - struct key_type *ktype; + unsigned long prealloc; struct key *keyring, *key = NULL; key_ref_t key_ref; int ret; /* look up the key type to see if it's one of the registered kernel * types */ - ktype = key_type_lookup(type); - if (IS_ERR(ktype)) { + index_key.type = key_type_lookup(type); + if (IS_ERR(index_key.type)) { key_ref = ERR_PTR(-ENODEV); goto error; } key_ref = ERR_PTR(-EINVAL); - if (!ktype->match || !ktype->instantiate || - (!description && !ktype->preparse)) + if (!index_key.type->match || !index_key.type->instantiate || + (!index_key.description && !index_key.type->preparse)) goto error_put_type; keyring = key_ref_to_ptr(keyring_ref); @@ -812,21 +813,22 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, memset(&prep, 0, sizeof(prep)); prep.data = payload; prep.datalen = plen; - prep.quotalen = ktype->def_datalen; - if (ktype->preparse) { - ret = ktype->preparse(&prep); + prep.quotalen = index_key.type->def_datalen; + if (index_key.type->preparse) { + ret = index_key.type->preparse(&prep); if (ret < 0) { key_ref = ERR_PTR(ret); goto error_put_type; } - if (!description) - description = prep.description; + if (!index_key.description) + index_key.description = prep.description; key_ref = ERR_PTR(-EINVAL); - if (!description) + if (!index_key.description) goto error_free_prep; } + index_key.desc_len = strlen(index_key.description); - ret = __key_link_begin(keyring, ktype, description, &prealloc); + ret = __key_link_begin(keyring, &index_key, &prealloc); if (ret < 0) { key_ref = ERR_PTR(ret); goto error_free_prep; @@ -844,9 +846,8 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, * key of the same type and description in the destination keyring and * update that instead if possible */ - if (ktype->update) { - key_ref = __keyring_search_one(keyring_ref, ktype, description, - 0); + if (index_key.type->update) { + key_ref = __keyring_search_one(keyring_ref, &index_key, 0); if (!IS_ERR(key_ref)) goto found_matching_key; } @@ -856,16 +857,17 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; perm |= KEY_USR_VIEW; - if (ktype->read) + if (index_key.type->read) perm |= KEY_POS_READ; - if (ktype == &key_type_keyring || ktype->update) + if (index_key.type == &key_type_keyring || + index_key.type->update) perm |= KEY_POS_WRITE; } /* allocate a new key */ - key = key_alloc(ktype, description, cred->fsuid, cred->fsgid, cred, - perm, flags); + key = key_alloc(index_key.type, index_key.description, + cred->fsuid, cred->fsgid, cred, perm, flags); if (IS_ERR(key)) { key_ref = ERR_CAST(key); goto error_link_end; @@ -882,12 +884,12 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, key_ref = make_key_ref(key, is_key_possessed(keyring_ref)); error_link_end: - __key_link_end(keyring, ktype, prealloc); + __key_link_end(keyring, &index_key, prealloc); error_free_prep: - if (ktype->preparse) - ktype->free_preparse(&prep); + if (index_key.type->preparse) + index_key.type->free_preparse(&prep); error_put_type: - key_type_put(ktype); + key_type_put(index_key.type); error: return key_ref; @@ -895,7 +897,7 @@ error: /* we found a matching key, so we're going to try to update it * - we can drop the locks first as we have the key pinned */ - __key_link_end(keyring, ktype, prealloc); + __key_link_end(keyring, &index_key, prealloc); key_ref = __key_update(key_ref, &prep); goto error_free_prep; diff --git a/security/keys/keyring.c b/security/keys/keyring.c index f78406372eb..c7f59f9dd7b 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -538,8 +538,7 @@ EXPORT_SYMBOL(keyring_search); * to the returned key reference. */ key_ref_t __keyring_search_one(key_ref_t keyring_ref, - const struct key_type *ktype, - const char *description, + const struct keyring_index_key *index_key, key_perm_t perm) { struct keyring_list *klist; @@ -558,9 +557,9 @@ key_ref_t __keyring_search_one(key_ref_t keyring_ref, smp_rmb(); for (loop = 0; loop < nkeys ; loop++) { key = rcu_dereference(klist->keys[loop]); - if (key->type == ktype && + if (key->type == index_key->type && (!key->type->match || - key->type->match(key, description)) && + key->type->match(key, index_key->description)) && key_permission(make_key_ref(key, possessed), perm) == 0 && !(key->flags & ((1 << KEY_FLAG_INVALIDATED) | @@ -747,8 +746,8 @@ static void keyring_unlink_rcu_disposal(struct rcu_head *rcu) /* * Preallocate memory so that a key can be linked into to a keyring. */ -int __key_link_begin(struct key *keyring, const struct key_type *type, - const char *description, unsigned long *_prealloc) +int __key_link_begin(struct key *keyring, const struct keyring_index_key *index_key, + unsigned long *_prealloc) __acquires(&keyring->sem) __acquires(&keyring_serialise_link_sem) { @@ -759,7 +758,8 @@ int __key_link_begin(struct key *keyring, const struct key_type *type, size_t size; int loop, lru, ret; - kenter("%d,%s,%s,", key_serial(keyring), type->name, description); + kenter("%d,%s,%s,", + key_serial(keyring), index_key->type->name, index_key->description); if (keyring->type != &key_type_keyring) return -ENOTDIR; @@ -772,7 +772,7 @@ int __key_link_begin(struct key *keyring, const struct key_type *type, /* serialise link/link calls to prevent parallel calls causing a cycle * when linking two keyring in opposite orders */ - if (type == &key_type_keyring) + if (index_key->type == &key_type_keyring) down_write(&keyring_serialise_link_sem); klist = rcu_dereference_locked_keyring(keyring); @@ -784,8 +784,8 @@ int __key_link_begin(struct key *keyring, const struct key_type *type, for (loop = klist->nkeys - 1; loop >= 0; loop--) { struct key *key = rcu_deref_link_locked(klist, loop, keyring); - if (key->type == type && - strcmp(key->description, description) == 0) { + if (key->type == index_key->type && + strcmp(key->description, index_key->description) == 0) { /* Found a match - we'll replace the link with * one to the new key. We record the slot * position. @@ -865,7 +865,7 @@ error_quota: key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES); error_sem: - if (type == &key_type_keyring) + if (index_key->type == &key_type_keyring) up_write(&keyring_serialise_link_sem); error_krsem: up_write(&keyring->sem); @@ -957,16 +957,17 @@ void __key_link(struct key *keyring, struct key *key, * * Must be called with __key_link_begin() having being called. */ -void __key_link_end(struct key *keyring, struct key_type *type, +void __key_link_end(struct key *keyring, + const struct keyring_index_key *index_key, unsigned long prealloc) __releases(&keyring->sem) __releases(&keyring_serialise_link_sem) { - BUG_ON(type == NULL); - BUG_ON(type->name == NULL); - kenter("%d,%s,%lx", keyring->serial, type->name, prealloc); + BUG_ON(index_key->type == NULL); + BUG_ON(index_key->type->name == NULL); + kenter("%d,%s,%lx", keyring->serial, index_key->type->name, prealloc); - if (type == &key_type_keyring) + if (index_key->type == &key_type_keyring) up_write(&keyring_serialise_link_sem); if (prealloc) { @@ -1007,12 +1008,12 @@ int key_link(struct key *keyring, struct key *key) key_check(keyring); key_check(key); - ret = __key_link_begin(keyring, key->type, key->description, &prealloc); + ret = __key_link_begin(keyring, &key->index_key, &prealloc); if (ret == 0) { ret = __key_link_check_live_key(keyring, key); if (ret == 0) __key_link(keyring, key, &prealloc); - __key_link_end(keyring, key->type, prealloc); + __key_link_end(keyring, &key->index_key, prealloc); } return ret; diff --git a/security/keys/request_key.c b/security/keys/request_key.c index 172115b3805..586cb79ee82 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -352,6 +352,11 @@ static int construct_alloc_key(struct key_type *type, struct key_user *user, struct key **_key) { + const struct keyring_index_key index_key = { + .type = type, + .description = description, + .desc_len = strlen(description), + }; const struct cred *cred = current_cred(); unsigned long prealloc; struct key *key; @@ -379,8 +384,7 @@ static int construct_alloc_key(struct key_type *type, set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags); if (dest_keyring) { - ret = __key_link_begin(dest_keyring, type, description, - &prealloc); + ret = __key_link_begin(dest_keyring, &index_key, &prealloc); if (ret < 0) goto link_prealloc_failed; } @@ -400,7 +404,7 @@ static int construct_alloc_key(struct key_type *type, mutex_unlock(&key_construction_mutex); if (dest_keyring) - __key_link_end(dest_keyring, type, prealloc); + __key_link_end(dest_keyring, &index_key, prealloc); mutex_unlock(&user->cons_lock); *_key = key; kleave(" = 0 [%d]", key_serial(key)); @@ -416,7 +420,7 @@ key_already_present: ret = __key_link_check_live_key(dest_keyring, key); if (ret == 0) __key_link(dest_keyring, key, &prealloc); - __key_link_end(dest_keyring, type, prealloc); + __key_link_end(dest_keyring, &index_key, prealloc); if (ret < 0) goto link_check_failed; } -- cgit v1.2.3-70-g09d2 From 4bdf0bc300314141e5475e145acb8b5ad846f00d Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:15 +0100 Subject: KEYS: Introduce a search context structure Search functions pass around a bunch of arguments, each of which gets copied with each call. Introduce a search context structure to hold these. Whilst we're at it, create a search flag that indicates whether the search should be directly to the description or whether it should iterate through all keys looking for a non-description match. This will be useful when keyrings use a generic data struct with generic routines to manage their content as the search terms can just be passed through to the iterator callback function. Also, for future use, the data to be supplied to the match function is separated from the description pointer in the search context. This makes it clear which is being supplied. Signed-off-by: David Howells --- include/linux/key-type.h | 5 ++ security/keys/internal.h | 40 +++++++------ security/keys/keyring.c | 70 +++++++++++------------ security/keys/proc.c | 17 ++++-- security/keys/process_keys.c | 117 +++++++++++++++++++-------------------- security/keys/request_key.c | 56 +++++++++---------- security/keys/request_key_auth.c | 14 +++-- security/keys/user_defined.c | 18 +++--- 8 files changed, 179 insertions(+), 158 deletions(-) (limited to 'security/keys') diff --git a/include/linux/key-type.h b/include/linux/key-type.h index 518a53afb9e..f58737bcb05 100644 --- a/include/linux/key-type.h +++ b/include/linux/key-type.h @@ -63,6 +63,11 @@ struct key_type { */ size_t def_datalen; + /* Default key search algorithm. */ + unsigned def_lookup_type; +#define KEYRING_SEARCH_LOOKUP_DIRECT 0x0000 /* Direct lookup by description. */ +#define KEYRING_SEARCH_LOOKUP_ITERATE 0x0001 /* Iterative search. */ + /* vet a description */ int (*vet_description)(const char *description); diff --git a/security/keys/internal.h b/security/keys/internal.h index 77441dd1f9d..f4bf938b68b 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -107,23 +107,31 @@ extern struct key *keyring_search_instkey(struct key *keyring, typedef int (*key_match_func_t)(const struct key *, const void *); +struct keyring_search_context { + struct keyring_index_key index_key; + const struct cred *cred; + key_match_func_t match; + const void *match_data; + unsigned flags; +#define KEYRING_SEARCH_LOOKUP_TYPE 0x0001 /* [as type->def_lookup_type] */ +#define KEYRING_SEARCH_NO_STATE_CHECK 0x0002 /* Skip state checks */ +#define KEYRING_SEARCH_DO_STATE_CHECK 0x0004 /* Override NO_STATE_CHECK */ +#define KEYRING_SEARCH_NO_UPDATE_TIME 0x0008 /* Don't update times */ +#define KEYRING_SEARCH_NO_CHECK_PERM 0x0010 /* Don't check permissions */ +#define KEYRING_SEARCH_DETECT_TOO_DEEP 0x0020 /* Give an error on excessive depth */ + + /* Internal stuff */ + int skipped_ret; + bool possessed; + key_ref_t result; + struct timespec now; +}; + extern key_ref_t keyring_search_aux(key_ref_t keyring_ref, - const struct cred *cred, - struct key_type *type, - const void *description, - key_match_func_t match, - bool no_state_check); - -extern key_ref_t search_my_process_keyrings(struct key_type *type, - const void *description, - key_match_func_t match, - bool no_state_check, - const struct cred *cred); -extern key_ref_t search_process_keyrings(struct key_type *type, - const void *description, - key_match_func_t match, - bool no_state_check, - const struct cred *cred); + struct keyring_search_context *ctx); + +extern key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx); +extern key_ref_t search_process_keyrings(struct keyring_search_context *ctx); extern struct key *find_keyring_by_name(const char *name, bool skip_perm_check); diff --git a/security/keys/keyring.c b/security/keys/keyring.c index c7f59f9dd7b..b42f2d4f7f8 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -280,11 +280,7 @@ EXPORT_SYMBOL(keyring_alloc); /** * keyring_search_aux - Search a keyring tree for a key matching some criteria * @keyring_ref: A pointer to the keyring with possession indicator. - * @cred: The credentials to use for permissions checks. - * @type: The type of key to search for. - * @description: Parameter for @match. - * @match: Function to rule on whether or not a key is the one required. - * @no_state_check: Don't check if a matching key is bad + * @ctx: The keyring search context. * * Search the supplied keyring tree for a key that matches the criteria given. * The root keyring and any linked keyrings must grant Search permission to the @@ -314,11 +310,7 @@ EXPORT_SYMBOL(keyring_alloc); * @keyring_ref is propagated to the returned key reference. */ key_ref_t keyring_search_aux(key_ref_t keyring_ref, - const struct cred *cred, - struct key_type *type, - const void *description, - key_match_func_t match, - bool no_state_check) + struct keyring_search_context *ctx) { struct { /* Need a separate keylist pointer for RCU purposes */ @@ -328,20 +320,18 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref, } stack[KEYRING_SEARCH_MAX_DEPTH]; struct keyring_list *keylist; - struct timespec now; unsigned long kflags; struct key *keyring, *key; key_ref_t key_ref; - bool possessed; long err; int sp, nkeys, kix; keyring = key_ref_to_ptr(keyring_ref); - possessed = is_key_possessed(keyring_ref); + ctx->possessed = is_key_possessed(keyring_ref); key_check(keyring); /* top keyring must have search permission to begin the search */ - err = key_task_permission(keyring_ref, cred, KEY_SEARCH); + err = key_task_permission(keyring_ref, ctx->cred, KEY_SEARCH); if (err < 0) { key_ref = ERR_PTR(err); goto error; @@ -353,7 +343,7 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref, rcu_read_lock(); - now = current_kernel_time(); + ctx->now = current_kernel_time(); err = -EAGAIN; sp = 0; @@ -361,16 +351,17 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref, * are looking for */ key_ref = ERR_PTR(-EAGAIN); kflags = keyring->flags; - if (keyring->type == type && match(keyring, description)) { + if (keyring->type == ctx->index_key.type && + ctx->match(keyring, ctx->match_data)) { key = keyring; - if (no_state_check) + if (ctx->flags & KEYRING_SEARCH_NO_STATE_CHECK) goto found; /* check it isn't negative and hasn't expired or been * revoked */ if (kflags & (1 << KEY_FLAG_REVOKED)) goto error_2; - if (key->expiry && now.tv_sec >= key->expiry) + if (key->expiry && ctx->now.tv_sec >= key->expiry) goto error_2; key_ref = ERR_PTR(key->type_data.reject_error); if (kflags & (1 << KEY_FLAG_NEGATIVE)) @@ -384,7 +375,7 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref, if (kflags & ((1 << KEY_FLAG_INVALIDATED) | (1 << KEY_FLAG_REVOKED) | (1 << KEY_FLAG_NEGATIVE)) || - (keyring->expiry && now.tv_sec >= keyring->expiry)) + (keyring->expiry && ctx->now.tv_sec >= keyring->expiry)) goto error_2; /* start processing a new keyring */ @@ -406,29 +397,29 @@ descend: kflags = key->flags; /* ignore keys not of this type */ - if (key->type != type) + if (key->type != ctx->index_key.type) continue; /* skip invalidated, revoked and expired keys */ - if (!no_state_check) { + if (!(ctx->flags & KEYRING_SEARCH_NO_STATE_CHECK)) { if (kflags & ((1 << KEY_FLAG_INVALIDATED) | (1 << KEY_FLAG_REVOKED))) continue; - if (key->expiry && now.tv_sec >= key->expiry) + if (key->expiry && ctx->now.tv_sec >= key->expiry) continue; } /* keys that don't match */ - if (!match(key, description)) + if (!ctx->match(key, ctx->match_data)) continue; /* key must have search permissions */ - if (key_task_permission(make_key_ref(key, possessed), - cred, KEY_SEARCH) < 0) + if (key_task_permission(make_key_ref(key, ctx->possessed), + ctx->cred, KEY_SEARCH) < 0) continue; - if (no_state_check) + if (ctx->flags & KEYRING_SEARCH_NO_STATE_CHECK) goto found; /* we set a different error code if we pass a negative key */ @@ -456,8 +447,8 @@ ascend: if (sp >= KEYRING_SEARCH_MAX_DEPTH) continue; - if (key_task_permission(make_key_ref(key, possessed), - cred, KEY_SEARCH) < 0) + if (key_task_permission(make_key_ref(key, ctx->possessed), + ctx->cred, KEY_SEARCH) < 0) continue; /* stack the current position */ @@ -489,12 +480,12 @@ not_this_keyring: /* we found a viable match */ found: atomic_inc(&key->usage); - key->last_used_at = now.tv_sec; - keyring->last_used_at = now.tv_sec; + key->last_used_at = ctx->now.tv_sec; + keyring->last_used_at = ctx->now.tv_sec; while (sp > 0) - stack[--sp].keyring->last_used_at = now.tv_sec; + stack[--sp].keyring->last_used_at = ctx->now.tv_sec; key_check(key); - key_ref = make_key_ref(key, possessed); + key_ref = make_key_ref(key, ctx->possessed); error_2: rcu_read_unlock(); error: @@ -514,11 +505,20 @@ key_ref_t keyring_search(key_ref_t keyring, struct key_type *type, const char *description) { - if (!type->match) + struct keyring_search_context ctx = { + .index_key.type = type, + .index_key.description = description, + .cred = current_cred(), + .match = type->match, + .match_data = description, + .flags = (type->def_lookup_type | + KEYRING_SEARCH_DO_STATE_CHECK), + }; + + if (!ctx.match) return ERR_PTR(-ENOKEY); - return keyring_search_aux(keyring, current->cred, - type, description, type->match, false); + return keyring_search_aux(keyring, &ctx); } EXPORT_SYMBOL(keyring_search); diff --git a/security/keys/proc.c b/security/keys/proc.c index 217b6855e81..88e9a466940 100644 --- a/security/keys/proc.c +++ b/security/keys/proc.c @@ -182,7 +182,6 @@ static void proc_keys_stop(struct seq_file *p, void *v) static int proc_keys_show(struct seq_file *m, void *v) { - const struct cred *cred = current_cred(); struct rb_node *_p = v; struct key *key = rb_entry(_p, struct key, serial_node); struct timespec now; @@ -191,15 +190,23 @@ static int proc_keys_show(struct seq_file *m, void *v) char xbuf[12]; int rc; + struct keyring_search_context ctx = { + .index_key.type = key->type, + .index_key.description = key->description, + .cred = current_cred(), + .match = lookup_user_key_possessed, + .match_data = key, + .flags = (KEYRING_SEARCH_NO_STATE_CHECK | + KEYRING_SEARCH_LOOKUP_DIRECT), + }; + key_ref = make_key_ref(key, 0); /* determine if the key is possessed by this process (a test we can * skip if the key does not indicate the possessor can view it */ if (key->perm & KEY_POS_VIEW) { - skey_ref = search_my_process_keyrings(key->type, key, - lookup_user_key_possessed, - true, cred); + skey_ref = search_my_process_keyrings(&ctx); if (!IS_ERR(skey_ref)) { key_ref_put(skey_ref); key_ref = make_key_ref(key, 1); @@ -211,7 +218,7 @@ static int proc_keys_show(struct seq_file *m, void *v) * - the caller holds a spinlock, and thus the RCU read lock, making our * access to __current_cred() safe */ - rc = key_task_permission(key_ref, cred, KEY_VIEW); + rc = key_task_permission(key_ref, ctx.cred, KEY_VIEW); if (rc < 0) return 0; diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c index a3410d60584..e68a3e0e7aa 100644 --- a/security/keys/process_keys.c +++ b/security/keys/process_keys.c @@ -319,11 +319,7 @@ void key_fsgid_changed(struct task_struct *tsk) * In the case of a successful return, the possession attribute is set on the * returned key reference. */ -key_ref_t search_my_process_keyrings(struct key_type *type, - const void *description, - key_match_func_t match, - bool no_state_check, - const struct cred *cred) +key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx) { key_ref_t key_ref, ret, err; @@ -339,10 +335,9 @@ key_ref_t search_my_process_keyrings(struct key_type *type, err = ERR_PTR(-EAGAIN); /* search the thread keyring first */ - if (cred->thread_keyring) { + if (ctx->cred->thread_keyring) { key_ref = keyring_search_aux( - make_key_ref(cred->thread_keyring, 1), - cred, type, description, match, no_state_check); + make_key_ref(ctx->cred->thread_keyring, 1), ctx); if (!IS_ERR(key_ref)) goto found; @@ -358,10 +353,9 @@ key_ref_t search_my_process_keyrings(struct key_type *type, } /* search the process keyring second */ - if (cred->process_keyring) { + if (ctx->cred->process_keyring) { key_ref = keyring_search_aux( - make_key_ref(cred->process_keyring, 1), - cred, type, description, match, no_state_check); + make_key_ref(ctx->cred->process_keyring, 1), ctx); if (!IS_ERR(key_ref)) goto found; @@ -379,11 +373,11 @@ key_ref_t search_my_process_keyrings(struct key_type *type, } /* search the session keyring */ - if (cred->session_keyring) { + if (ctx->cred->session_keyring) { rcu_read_lock(); key_ref = keyring_search_aux( - make_key_ref(rcu_dereference(cred->session_keyring), 1), - cred, type, description, match, no_state_check); + make_key_ref(rcu_dereference(ctx->cred->session_keyring), 1), + ctx); rcu_read_unlock(); if (!IS_ERR(key_ref)) @@ -402,10 +396,10 @@ key_ref_t search_my_process_keyrings(struct key_type *type, } } /* or search the user-session keyring */ - else if (cred->user->session_keyring) { + else if (ctx->cred->user->session_keyring) { key_ref = keyring_search_aux( - make_key_ref(cred->user->session_keyring, 1), - cred, type, description, match, no_state_check); + make_key_ref(ctx->cred->user->session_keyring, 1), + ctx); if (!IS_ERR(key_ref)) goto found; @@ -437,19 +431,14 @@ found: * * Return same as search_my_process_keyrings(). */ -key_ref_t search_process_keyrings(struct key_type *type, - const void *description, - key_match_func_t match, - bool no_state_check, - const struct cred *cred) +key_ref_t search_process_keyrings(struct keyring_search_context *ctx) { struct request_key_auth *rka; key_ref_t key_ref, ret = ERR_PTR(-EACCES), err; might_sleep(); - key_ref = search_my_process_keyrings(type, description, match, - no_state_check, cred); + key_ref = search_my_process_keyrings(ctx); if (!IS_ERR(key_ref)) goto found; err = key_ref; @@ -458,19 +447,21 @@ key_ref_t search_process_keyrings(struct key_type *type, * search the keyrings of the process mentioned there * - we don't permit access to request_key auth keys via this method */ - if (cred->request_key_auth && - cred == current_cred() && - type != &key_type_request_key_auth + if (ctx->cred->request_key_auth && + ctx->cred == current_cred() && + ctx->index_key.type != &key_type_request_key_auth ) { + const struct cred *cred = ctx->cred; + /* defend against the auth key being revoked */ down_read(&cred->request_key_auth->sem); - if (key_validate(cred->request_key_auth) == 0) { - rka = cred->request_key_auth->payload.data; + if (key_validate(ctx->cred->request_key_auth) == 0) { + rka = ctx->cred->request_key_auth->payload.data; - key_ref = search_process_keyrings(type, description, - match, no_state_check, - rka->cred); + ctx->cred = rka->cred; + key_ref = search_process_keyrings(ctx); + ctx->cred = cred; up_read(&cred->request_key_auth->sem); @@ -524,19 +515,23 @@ int lookup_user_key_possessed(const struct key *key, const void *target) key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, key_perm_t perm) { + struct keyring_search_context ctx = { + .match = lookup_user_key_possessed, + .flags = (KEYRING_SEARCH_NO_STATE_CHECK | + KEYRING_SEARCH_LOOKUP_DIRECT), + }; struct request_key_auth *rka; - const struct cred *cred; struct key *key; key_ref_t key_ref, skey_ref; int ret; try_again: - cred = get_current_cred(); + ctx.cred = get_current_cred(); key_ref = ERR_PTR(-ENOKEY); switch (id) { case KEY_SPEC_THREAD_KEYRING: - if (!cred->thread_keyring) { + if (!ctx.cred->thread_keyring) { if (!(lflags & KEY_LOOKUP_CREATE)) goto error; @@ -548,13 +543,13 @@ try_again: goto reget_creds; } - key = cred->thread_keyring; + key = ctx.cred->thread_keyring; atomic_inc(&key->usage); key_ref = make_key_ref(key, 1); break; case KEY_SPEC_PROCESS_KEYRING: - if (!cred->process_keyring) { + if (!ctx.cred->process_keyring) { if (!(lflags & KEY_LOOKUP_CREATE)) goto error; @@ -566,13 +561,13 @@ try_again: goto reget_creds; } - key = cred->process_keyring; + key = ctx.cred->process_keyring; atomic_inc(&key->usage); key_ref = make_key_ref(key, 1); break; case KEY_SPEC_SESSION_KEYRING: - if (!cred->session_keyring) { + if (!ctx.cred->session_keyring) { /* always install a session keyring upon access if one * doesn't exist yet */ ret = install_user_keyrings(); @@ -582,13 +577,13 @@ try_again: ret = join_session_keyring(NULL); else ret = install_session_keyring( - cred->user->session_keyring); + ctx.cred->user->session_keyring); if (ret < 0) goto error; goto reget_creds; - } else if (cred->session_keyring == - cred->user->session_keyring && + } else if (ctx.cred->session_keyring == + ctx.cred->user->session_keyring && lflags & KEY_LOOKUP_CREATE) { ret = join_session_keyring(NULL); if (ret < 0) @@ -597,32 +592,32 @@ try_again: } rcu_read_lock(); - key = rcu_dereference(cred->session_keyring); + key = rcu_dereference(ctx.cred->session_keyring); atomic_inc(&key->usage); rcu_read_unlock(); key_ref = make_key_ref(key, 1); break; case KEY_SPEC_USER_KEYRING: - if (!cred->user->uid_keyring) { + if (!ctx.cred->user->uid_keyring) { ret = install_user_keyrings(); if (ret < 0) goto error; } - key = cred->user->uid_keyring; + key = ctx.cred->user->uid_keyring; atomic_inc(&key->usage); key_ref = make_key_ref(key, 1); break; case KEY_SPEC_USER_SESSION_KEYRING: - if (!cred->user->session_keyring) { + if (!ctx.cred->user->session_keyring) { ret = install_user_keyrings(); if (ret < 0) goto error; } - key = cred->user->session_keyring; + key = ctx.cred->user->session_keyring; atomic_inc(&key->usage); key_ref = make_key_ref(key, 1); break; @@ -633,7 +628,7 @@ try_again: goto error; case KEY_SPEC_REQKEY_AUTH_KEY: - key = cred->request_key_auth; + key = ctx.cred->request_key_auth; if (!key) goto error; @@ -642,20 +637,20 @@ try_again: break; case KEY_SPEC_REQUESTOR_KEYRING: - if (!cred->request_key_auth) + if (!ctx.cred->request_key_auth) goto error; - down_read(&cred->request_key_auth->sem); + down_read(&ctx.cred->request_key_auth->sem); if (test_bit(KEY_FLAG_REVOKED, - &cred->request_key_auth->flags)) { + &ctx.cred->request_key_auth->flags)) { key_ref = ERR_PTR(-EKEYREVOKED); key = NULL; } else { - rka = cred->request_key_auth->payload.data; + rka = ctx.cred->request_key_auth->payload.data; key = rka->dest_keyring; atomic_inc(&key->usage); } - up_read(&cred->request_key_auth->sem); + up_read(&ctx.cred->request_key_auth->sem); if (!key) goto error; key_ref = make_key_ref(key, 1); @@ -675,9 +670,13 @@ try_again: key_ref = make_key_ref(key, 0); /* check to see if we possess the key */ - skey_ref = search_process_keyrings(key->type, key, - lookup_user_key_possessed, - true, cred); + ctx.index_key.type = key->type; + ctx.index_key.description = key->description; + ctx.index_key.desc_len = strlen(key->description); + ctx.match_data = key; + kdebug("check possessed"); + skey_ref = search_process_keyrings(&ctx); + kdebug("possessed=%p", skey_ref); if (!IS_ERR(skey_ref)) { key_put(key); @@ -717,14 +716,14 @@ try_again: goto invalid_key; /* check the permissions */ - ret = key_task_permission(key_ref, cred, perm); + ret = key_task_permission(key_ref, ctx.cred, perm); if (ret < 0) goto invalid_key; key->last_used_at = current_kernel_time().tv_sec; error: - put_cred(cred); + put_cred(ctx.cred); return key_ref; invalid_key: @@ -735,7 +734,7 @@ invalid_key: /* if we attempted to install a keyring, then it may have caused new * creds to be installed */ reget_creds: - put_cred(cred); + put_cred(ctx.cred); goto try_again; } diff --git a/security/keys/request_key.c b/security/keys/request_key.c index 586cb79ee82..ab75df4745a 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -345,38 +345,34 @@ static void construct_get_dest_keyring(struct key **_dest_keyring) * May return a key that's already under construction instead if there was a * race between two thread calling request_key(). */ -static int construct_alloc_key(struct key_type *type, - const char *description, +static int construct_alloc_key(struct keyring_search_context *ctx, struct key *dest_keyring, unsigned long flags, struct key_user *user, struct key **_key) { - const struct keyring_index_key index_key = { - .type = type, - .description = description, - .desc_len = strlen(description), - }; - const struct cred *cred = current_cred(); unsigned long prealloc; struct key *key; key_perm_t perm; key_ref_t key_ref; int ret; - kenter("%s,%s,,,", type->name, description); + kenter("%s,%s,,,", + ctx->index_key.type->name, ctx->index_key.description); *_key = NULL; mutex_lock(&user->cons_lock); perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; perm |= KEY_USR_VIEW; - if (type->read) + if (ctx->index_key.type->read) perm |= KEY_POS_READ; - if (type == &key_type_keyring || type->update) + if (ctx->index_key.type == &key_type_keyring || + ctx->index_key.type->update) perm |= KEY_POS_WRITE; - key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred, + key = key_alloc(ctx->index_key.type, ctx->index_key.description, + ctx->cred->fsuid, ctx->cred->fsgid, ctx->cred, perm, flags); if (IS_ERR(key)) goto alloc_failed; @@ -384,7 +380,7 @@ static int construct_alloc_key(struct key_type *type, set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags); if (dest_keyring) { - ret = __key_link_begin(dest_keyring, &index_key, &prealloc); + ret = __key_link_begin(dest_keyring, &ctx->index_key, &prealloc); if (ret < 0) goto link_prealloc_failed; } @@ -394,8 +390,7 @@ static int construct_alloc_key(struct key_type *type, * waited for locks */ mutex_lock(&key_construction_mutex); - key_ref = search_process_keyrings(type, description, type->match, - false, cred); + key_ref = search_process_keyrings(ctx); if (!IS_ERR(key_ref)) goto key_already_present; @@ -404,7 +399,7 @@ static int construct_alloc_key(struct key_type *type, mutex_unlock(&key_construction_mutex); if (dest_keyring) - __key_link_end(dest_keyring, &index_key, prealloc); + __key_link_end(dest_keyring, &ctx->index_key, prealloc); mutex_unlock(&user->cons_lock); *_key = key; kleave(" = 0 [%d]", key_serial(key)); @@ -420,7 +415,7 @@ key_already_present: ret = __key_link_check_live_key(dest_keyring, key); if (ret == 0) __key_link(dest_keyring, key, &prealloc); - __key_link_end(dest_keyring, &index_key, prealloc); + __key_link_end(dest_keyring, &ctx->index_key, prealloc); if (ret < 0) goto link_check_failed; } @@ -449,8 +444,7 @@ alloc_failed: /* * Commence key construction. */ -static struct key *construct_key_and_link(struct key_type *type, - const char *description, +static struct key *construct_key_and_link(struct keyring_search_context *ctx, const char *callout_info, size_t callout_len, void *aux, @@ -469,8 +463,7 @@ static struct key *construct_key_and_link(struct key_type *type, construct_get_dest_keyring(&dest_keyring); - ret = construct_alloc_key(type, description, dest_keyring, flags, user, - &key); + ret = construct_alloc_key(ctx, dest_keyring, flags, user, &key); key_user_put(user); if (ret == 0) { @@ -534,18 +527,24 @@ struct key *request_key_and_link(struct key_type *type, struct key *dest_keyring, unsigned long flags) { - const struct cred *cred = current_cred(); + struct keyring_search_context ctx = { + .index_key.type = type, + .index_key.description = description, + .cred = current_cred(), + .match = type->match, + .match_data = description, + .flags = KEYRING_SEARCH_LOOKUP_DIRECT, + }; struct key *key; key_ref_t key_ref; int ret; kenter("%s,%s,%p,%zu,%p,%p,%lx", - type->name, description, callout_info, callout_len, aux, - dest_keyring, flags); + ctx.index_key.type->name, ctx.index_key.description, + callout_info, callout_len, aux, dest_keyring, flags); /* search all the process keyrings for a key */ - key_ref = search_process_keyrings(type, description, type->match, - false, cred); + key_ref = search_process_keyrings(&ctx); if (!IS_ERR(key_ref)) { key = key_ref_to_ptr(key_ref); @@ -568,9 +567,8 @@ struct key *request_key_and_link(struct key_type *type, if (!callout_info) goto error; - key = construct_key_and_link(type, description, callout_info, - callout_len, aux, dest_keyring, - flags); + key = construct_key_and_link(&ctx, callout_info, callout_len, + aux, dest_keyring, flags); } error: diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c index 92077de555d..8d09852854c 100644 --- a/security/keys/request_key_auth.c +++ b/security/keys/request_key_auth.c @@ -239,15 +239,17 @@ static int key_get_instantiation_authkey_match(const struct key *key, */ struct key *key_get_instantiation_authkey(key_serial_t target_id) { - const struct cred *cred = current_cred(); + struct keyring_search_context ctx = { + .index_key.type = &key_type_request_key_auth, + .cred = current_cred(), + .match = key_get_instantiation_authkey_match, + .match_data = (void *)(unsigned long)target_id, + .flags = KEYRING_SEARCH_LOOKUP_DIRECT, + }; struct key *authkey; key_ref_t authkey_ref; - authkey_ref = search_process_keyrings( - &key_type_request_key_auth, - (void *) (unsigned long) target_id, - key_get_instantiation_authkey_match, - false, cred); + authkey_ref = search_process_keyrings(&ctx); if (IS_ERR(authkey_ref)) { authkey = ERR_CAST(authkey_ref); diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c index 55dc8893918..faa2caeb593 100644 --- a/security/keys/user_defined.c +++ b/security/keys/user_defined.c @@ -25,14 +25,15 @@ static int logon_vet_description(const char *desc); * arbitrary blob of data as the payload */ struct key_type key_type_user = { - .name = "user", - .instantiate = user_instantiate, - .update = user_update, - .match = user_match, - .revoke = user_revoke, - .destroy = user_destroy, - .describe = user_describe, - .read = user_read, + .name = "user", + .def_lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, + .instantiate = user_instantiate, + .update = user_update, + .match = user_match, + .revoke = user_revoke, + .destroy = user_destroy, + .describe = user_describe, + .read = user_read, }; EXPORT_SYMBOL_GPL(key_type_user); @@ -45,6 +46,7 @@ EXPORT_SYMBOL_GPL(key_type_user); */ struct key_type key_type_logon = { .name = "logon", + .def_lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, .instantiate = user_instantiate, .update = user_update, .match = user_match, -- cgit v1.2.3-70-g09d2 From d0a059cac6523b23ad7d743dec8783705aab1668 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:16 +0100 Subject: KEYS: Search for auth-key by name rather than target key ID Search for auth-key by name rather than by target key ID as, in a future patch, we'll by searching directly by index key in preference to iteration over all keys. Signed-off-by: David Howells --- security/keys/request_key_auth.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-) (limited to 'security/keys') diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c index 8d09852854c..7495a93b4b9 100644 --- a/security/keys/request_key_auth.c +++ b/security/keys/request_key_auth.c @@ -18,6 +18,7 @@ #include #include #include "internal.h" +#include static int request_key_auth_instantiate(struct key *, struct key_preparsed_payload *); @@ -221,34 +222,26 @@ error_alloc: return ERR_PTR(ret); } -/* - * See if an authorisation key is associated with a particular key. - */ -static int key_get_instantiation_authkey_match(const struct key *key, - const void *_id) -{ - struct request_key_auth *rka = key->payload.data; - key_serial_t id = (key_serial_t)(unsigned long) _id; - - return rka->target_key->serial == id; -} - /* * Search the current process's keyrings for the authorisation key for * instantiation of a key. */ struct key *key_get_instantiation_authkey(key_serial_t target_id) { + char description[16]; struct keyring_search_context ctx = { .index_key.type = &key_type_request_key_auth, + .index_key.description = description, .cred = current_cred(), - .match = key_get_instantiation_authkey_match, - .match_data = (void *)(unsigned long)target_id, + .match = user_match, + .match_data = description, .flags = KEYRING_SEARCH_LOOKUP_DIRECT, }; struct key *authkey; key_ref_t authkey_ref; + sprintf(description, "%x", target_id); + authkey_ref = search_process_keyrings(&ctx); if (IS_ERR(authkey_ref)) { -- cgit v1.2.3-70-g09d2 From ccc3e6d9c9aea07a0b60b2b0bfc5b05a704b66d5 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:16 +0100 Subject: KEYS: Define a __key_get() wrapper to use rather than atomic_inc() Define a __key_get() wrapper to use rather than atomic_inc() on the key usage count as this makes it easier to hook in refcount error debugging. Signed-off-by: David Howells --- Documentation/security/keys.txt | 13 ++++++++----- include/linux/key.h | 10 +++++++--- security/keys/key.c | 2 +- security/keys/keyring.c | 6 +++--- security/keys/process_keys.c | 16 ++++++++-------- 5 files changed, 27 insertions(+), 20 deletions(-) (limited to 'security/keys') diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt index 9ede67084f0..a4c33f1a7c6 100644 --- a/Documentation/security/keys.txt +++ b/Documentation/security/keys.txt @@ -960,14 +960,17 @@ payload contents" for more information. the argument will not be parsed. -(*) Extra references can be made to a key by calling the following function: +(*) Extra references can be made to a key by calling one of the following + functions: + struct key *__key_get(struct key *key); struct key *key_get(struct key *key); - These need to be disposed of by calling key_put() when they've been - finished with. The key pointer passed in will be returned. If the pointer - is NULL or CONFIG_KEYS is not set then the key will not be dereferenced and - no increment will take place. + Keys so references will need to be disposed of by calling key_put() when + they've been finished with. The key pointer passed in will be returned. + + In the case of key_get(), if the pointer is NULL or CONFIG_KEYS is not set + then the key will not be dereferenced and no increment will take place. (*) A key's serial number can be obtained by calling: diff --git a/include/linux/key.h b/include/linux/key.h index d573e820a23..ef596c7af58 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -219,13 +219,17 @@ extern void key_revoke(struct key *key); extern void key_invalidate(struct key *key); extern void key_put(struct key *key); -static inline struct key *key_get(struct key *key) +static inline struct key *__key_get(struct key *key) { - if (key) - atomic_inc(&key->usage); + atomic_inc(&key->usage); return key; } +static inline struct key *key_get(struct key *key) +{ + return key ? __key_get(key) : key; +} + static inline void key_ref_put(key_ref_t key_ref) { key_put(key_ref_to_ptr(key_ref)); diff --git a/security/keys/key.c b/security/keys/key.c index 7e6bc396bb2..1e23cc28810 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -644,7 +644,7 @@ found: /* this races with key_put(), but that doesn't matter since key_put() * doesn't actually change the key */ - atomic_inc(&key->usage); + __key_get(key); error: spin_unlock(&key_serial_lock); diff --git a/security/keys/keyring.c b/security/keys/keyring.c index b42f2d4f7f8..87eff32b53f 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -479,7 +479,7 @@ not_this_keyring: /* we found a viable match */ found: - atomic_inc(&key->usage); + __key_get(key); key->last_used_at = ctx->now.tv_sec; keyring->last_used_at = ctx->now.tv_sec; while (sp > 0) @@ -573,7 +573,7 @@ key_ref_t __keyring_search_one(key_ref_t keyring_ref, return ERR_PTR(-ENOKEY); found: - atomic_inc(&key->usage); + __key_get(key); keyring->last_used_at = key->last_used_at = current_kernel_time().tv_sec; rcu_read_unlock(); @@ -909,7 +909,7 @@ void __key_link(struct key *keyring, struct key *key, klist = rcu_dereference_locked_keyring(keyring); - atomic_inc(&key->usage); + __key_get(key); keyring->last_used_at = key->last_used_at = current_kernel_time().tv_sec; diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c index e68a3e0e7aa..68548ea6fe0 100644 --- a/security/keys/process_keys.c +++ b/security/keys/process_keys.c @@ -235,7 +235,7 @@ int install_session_keyring_to_cred(struct cred *cred, struct key *keyring) if (IS_ERR(keyring)) return PTR_ERR(keyring); } else { - atomic_inc(&keyring->usage); + __key_get(keyring); } /* install the keyring */ @@ -544,7 +544,7 @@ try_again: } key = ctx.cred->thread_keyring; - atomic_inc(&key->usage); + __key_get(key); key_ref = make_key_ref(key, 1); break; @@ -562,7 +562,7 @@ try_again: } key = ctx.cred->process_keyring; - atomic_inc(&key->usage); + __key_get(key); key_ref = make_key_ref(key, 1); break; @@ -593,7 +593,7 @@ try_again: rcu_read_lock(); key = rcu_dereference(ctx.cred->session_keyring); - atomic_inc(&key->usage); + __key_get(key); rcu_read_unlock(); key_ref = make_key_ref(key, 1); break; @@ -606,7 +606,7 @@ try_again: } key = ctx.cred->user->uid_keyring; - atomic_inc(&key->usage); + __key_get(key); key_ref = make_key_ref(key, 1); break; @@ -618,7 +618,7 @@ try_again: } key = ctx.cred->user->session_keyring; - atomic_inc(&key->usage); + __key_get(key); key_ref = make_key_ref(key, 1); break; @@ -632,7 +632,7 @@ try_again: if (!key) goto error; - atomic_inc(&key->usage); + __key_get(key); key_ref = make_key_ref(key, 1); break; @@ -648,7 +648,7 @@ try_again: } else { rka = ctx.cred->request_key_auth->payload.data; key = rka->dest_keyring; - atomic_inc(&key->usage); + __key_get(key); } up_read(&ctx.cred->request_key_auth->sem); if (!key) -- cgit v1.2.3-70-g09d2 From e57e8669f2ab8350d30f771dd2fdd5377f183db2 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:17 +0100 Subject: KEYS: Drop the permissions argument from __keyring_search_one() Drop the permissions argument from __keyring_search_one() as the only caller passes 0 here - which causes all checks to be skipped. Signed-off-by: David Howells --- security/keys/internal.h | 3 +-- security/keys/key.c | 2 +- security/keys/keyring.c | 9 +++------ 3 files changed, 5 insertions(+), 9 deletions(-) (limited to 'security/keys') diff --git a/security/keys/internal.h b/security/keys/internal.h index f4bf938b68b..73950bf8f87 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -99,8 +99,7 @@ extern void __key_link_end(struct key *keyring, unsigned long prealloc); extern key_ref_t __keyring_search_one(key_ref_t keyring_ref, - const struct keyring_index_key *index_key, - key_perm_t perm); + const struct keyring_index_key *index_key); extern struct key *keyring_search_instkey(struct key *keyring, key_serial_t target_id); diff --git a/security/keys/key.c b/security/keys/key.c index 1e23cc28810..7d716b82a61 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -847,7 +847,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, * update that instead if possible */ if (index_key.type->update) { - key_ref = __keyring_search_one(keyring_ref, &index_key, 0); + key_ref = __keyring_search_one(keyring_ref, &index_key); if (!IS_ERR(key_ref)) goto found_matching_key; } diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 87eff32b53f..eeef1a073db 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -531,15 +531,14 @@ EXPORT_SYMBOL(keyring_search); * RCU is used to make it unnecessary to lock the keyring key list here. * * Returns a pointer to the found key with usage count incremented if - * successful and returns -ENOKEY if not found. Revoked keys and keys not - * providing the requested permission are skipped over. + * successful and returns -ENOKEY if not found. Revoked and invalidated keys + * are skipped over. * * If successful, the possession indicator is propagated from the keyring ref * to the returned key reference. */ key_ref_t __keyring_search_one(key_ref_t keyring_ref, - const struct keyring_index_key *index_key, - key_perm_t perm) + const struct keyring_index_key *index_key) { struct keyring_list *klist; struct key *keyring, *key; @@ -560,8 +559,6 @@ key_ref_t __keyring_search_one(key_ref_t keyring_ref, if (key->type == index_key->type && (!key->type->match || key->type->match(key, index_key->description)) && - key_permission(make_key_ref(key, possessed), - perm) == 0 && !(key->flags & ((1 << KEY_FLAG_INVALIDATED) | (1 << KEY_FLAG_REVOKED))) ) -- cgit v1.2.3-70-g09d2 From b2a4df200d570b2c33a57e1ebfa5896e4bc81b69 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:18 +0100 Subject: KEYS: Expand the capacity of a keyring Expand the capacity of a keyring to be able to hold a lot more keys by using the previously added associative array implementation. Currently the maximum capacity is: (PAGE_SIZE - sizeof(header)) / sizeof(struct key *) which, on a 64-bit system, is a little more 500. However, since this is being used for the NFS uid mapper, we need more than that. The new implementation gives us effectively unlimited capacity. With some alterations, the keyutils testsuite runs successfully to completion after this patch is applied. The alterations are because (a) keyrings that are simply added to no longer appear ordered and (b) some of the errors have changed a bit. Signed-off-by: David Howells --- include/keys/keyring-type.h | 17 +- include/linux/key.h | 13 +- lib/assoc_array.c | 1 + security/keys/Kconfig | 1 + security/keys/gc.c | 33 +- security/keys/internal.h | 17 +- security/keys/key.c | 35 +- security/keys/keyring.c | 1436 ++++++++++++++++++++++--------------------- security/keys/request_key.c | 12 +- 9 files changed, 803 insertions(+), 762 deletions(-) (limited to 'security/keys') diff --git a/include/keys/keyring-type.h b/include/keys/keyring-type.h index cf49159b0e3..fca5c62340a 100644 --- a/include/keys/keyring-type.h +++ b/include/keys/keyring-type.h @@ -1,6 +1,6 @@ /* Keyring key type * - * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. + * Copyright (C) 2008, 2013 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or @@ -13,19 +13,6 @@ #define _KEYS_KEYRING_TYPE_H #include -#include - -/* - * the keyring payload contains a list of the keys to which the keyring is - * subscribed - */ -struct keyring_list { - struct rcu_head rcu; /* RCU deletion hook */ - unsigned short maxkeys; /* max keys this list can hold */ - unsigned short nkeys; /* number of keys currently held */ - unsigned short delkey; /* key to be unlinked by RCU */ - struct key __rcu *keys[0]; -}; - +#include #endif /* _KEYS_KEYRING_TYPE_H */ diff --git a/include/linux/key.h b/include/linux/key.h index ef596c7af58..2417f789d29 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -22,6 +22,7 @@ #include #include #include +#include #ifdef __KERNEL__ #include @@ -196,11 +197,13 @@ struct key { * whatever */ union { - unsigned long value; - void __rcu *rcudata; - void *data; - struct keyring_list __rcu *subscriptions; - } payload; + union { + unsigned long value; + void __rcu *rcudata; + void *data; + } payload; + struct assoc_array keys; + }; }; extern struct key *key_alloc(struct key_type *type, diff --git a/lib/assoc_array.c b/lib/assoc_array.c index a0952818f93..17edeaf1918 100644 --- a/lib/assoc_array.c +++ b/lib/assoc_array.c @@ -12,6 +12,7 @@ */ //#define DEBUG #include +#include #include /* diff --git a/security/keys/Kconfig b/security/keys/Kconfig index a90d6d300db..15e0dfe8c80 100644 --- a/security/keys/Kconfig +++ b/security/keys/Kconfig @@ -4,6 +4,7 @@ config KEYS bool "Enable access key retention support" + select ASSOCIATIVE_ARRAY help This option provides support for retaining authentication tokens and access keys in the kernel. diff --git a/security/keys/gc.c b/security/keys/gc.c index d67c97bb102..cce621c33dc 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -130,6 +130,13 @@ void key_gc_keytype(struct key_type *ktype) kleave(""); } +static int key_gc_keyring_func(const void *object, void *iterator_data) +{ + const struct key *key = object; + time_t *limit = iterator_data; + return key_is_dead(key, *limit); +} + /* * Garbage collect pointers from a keyring. * @@ -138,10 +145,9 @@ void key_gc_keytype(struct key_type *ktype) */ static void key_gc_keyring(struct key *keyring, time_t limit) { - struct keyring_list *klist; - int loop; + int result; - kenter("%x", key_serial(keyring)); + kenter("%x{%s}", keyring->serial, keyring->description ?: ""); if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | (1 << KEY_FLAG_REVOKED))) @@ -149,27 +155,17 @@ static void key_gc_keyring(struct key *keyring, time_t limit) /* scan the keyring looking for dead keys */ rcu_read_lock(); - klist = rcu_dereference(keyring->payload.subscriptions); - if (!klist) - goto unlock_dont_gc; - - loop = klist->nkeys; - smp_rmb(); - for (loop--; loop >= 0; loop--) { - struct key *key = rcu_dereference(klist->keys[loop]); - if (key_is_dead(key, limit)) - goto do_gc; - } - -unlock_dont_gc: + result = assoc_array_iterate(&keyring->keys, + key_gc_keyring_func, &limit); rcu_read_unlock(); + if (result == true) + goto do_gc; + dont_gc: kleave(" [no gc]"); return; do_gc: - rcu_read_unlock(); - keyring_gc(keyring, limit); kleave(" [gc]"); } @@ -392,7 +388,6 @@ found_unreferenced_key: */ found_keyring: spin_unlock(&key_serial_lock); - kdebug("scan keyring %d", key->serial); key_gc_keyring(key, limit); goto maybe_resched; diff --git a/security/keys/internal.h b/security/keys/internal.h index 73950bf8f87..581c6f68835 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -90,20 +90,23 @@ extern void key_type_put(struct key_type *ktype); extern int __key_link_begin(struct key *keyring, const struct keyring_index_key *index_key, - unsigned long *_prealloc); + struct assoc_array_edit **_edit); extern int __key_link_check_live_key(struct key *keyring, struct key *key); -extern void __key_link(struct key *keyring, struct key *key, - unsigned long *_prealloc); +extern void __key_link(struct key *key, struct assoc_array_edit **_edit); extern void __key_link_end(struct key *keyring, const struct keyring_index_key *index_key, - unsigned long prealloc); + struct assoc_array_edit *edit); -extern key_ref_t __keyring_search_one(key_ref_t keyring_ref, - const struct keyring_index_key *index_key); +extern key_ref_t find_key_to_update(key_ref_t keyring_ref, + const struct keyring_index_key *index_key); extern struct key *keyring_search_instkey(struct key *keyring, key_serial_t target_id); +extern int iterate_over_keyring(const struct key *keyring, + int (*func)(const struct key *key, void *data), + void *data); + typedef int (*key_match_func_t)(const struct key *, const void *); struct keyring_search_context { @@ -119,6 +122,8 @@ struct keyring_search_context { #define KEYRING_SEARCH_NO_CHECK_PERM 0x0010 /* Don't check permissions */ #define KEYRING_SEARCH_DETECT_TOO_DEEP 0x0020 /* Give an error on excessive depth */ + int (*iterator)(const void *object, void *iterator_data); + /* Internal stuff */ int skipped_ret; bool possessed; diff --git a/security/keys/key.c b/security/keys/key.c index 7d716b82a61..a819b5c7d4e 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -409,7 +409,7 @@ static int __key_instantiate_and_link(struct key *key, struct key_preparsed_payload *prep, struct key *keyring, struct key *authkey, - unsigned long *_prealloc) + struct assoc_array_edit **_edit) { int ret, awaken; @@ -436,7 +436,7 @@ static int __key_instantiate_and_link(struct key *key, /* and link it into the destination keyring */ if (keyring) - __key_link(keyring, key, _prealloc); + __key_link(key, _edit); /* disable the authorisation key */ if (authkey) @@ -476,7 +476,7 @@ int key_instantiate_and_link(struct key *key, struct key *authkey) { struct key_preparsed_payload prep; - unsigned long prealloc; + struct assoc_array_edit *edit; int ret; memset(&prep, 0, sizeof(prep)); @@ -490,16 +490,15 @@ int key_instantiate_and_link(struct key *key, } if (keyring) { - ret = __key_link_begin(keyring, &key->index_key, &prealloc); + ret = __key_link_begin(keyring, &key->index_key, &edit); if (ret < 0) goto error_free_preparse; } - ret = __key_instantiate_and_link(key, &prep, keyring, authkey, - &prealloc); + ret = __key_instantiate_and_link(key, &prep, keyring, authkey, &edit); if (keyring) - __key_link_end(keyring, &key->index_key, prealloc); + __key_link_end(keyring, &key->index_key, edit); error_free_preparse: if (key->type->preparse) @@ -537,7 +536,7 @@ int key_reject_and_link(struct key *key, struct key *keyring, struct key *authkey) { - unsigned long prealloc; + struct assoc_array_edit *edit; struct timespec now; int ret, awaken, link_ret = 0; @@ -548,7 +547,7 @@ int key_reject_and_link(struct key *key, ret = -EBUSY; if (keyring) - link_ret = __key_link_begin(keyring, &key->index_key, &prealloc); + link_ret = __key_link_begin(keyring, &key->index_key, &edit); mutex_lock(&key_construction_mutex); @@ -570,7 +569,7 @@ int key_reject_and_link(struct key *key, /* and link it into the destination keyring */ if (keyring && link_ret == 0) - __key_link(keyring, key, &prealloc); + __key_link(key, &edit); /* disable the authorisation key */ if (authkey) @@ -580,7 +579,7 @@ int key_reject_and_link(struct key *key, mutex_unlock(&key_construction_mutex); if (keyring) - __key_link_end(keyring, &key->index_key, prealloc); + __key_link_end(keyring, &key->index_key, edit); /* wake up anyone waiting for a key to be constructed */ if (awaken) @@ -783,8 +782,8 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, .description = description, }; struct key_preparsed_payload prep; + struct assoc_array_edit *edit; const struct cred *cred = current_cred(); - unsigned long prealloc; struct key *keyring, *key = NULL; key_ref_t key_ref; int ret; @@ -828,7 +827,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, } index_key.desc_len = strlen(index_key.description); - ret = __key_link_begin(keyring, &index_key, &prealloc); + ret = __key_link_begin(keyring, &index_key, &edit); if (ret < 0) { key_ref = ERR_PTR(ret); goto error_free_prep; @@ -847,8 +846,8 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, * update that instead if possible */ if (index_key.type->update) { - key_ref = __keyring_search_one(keyring_ref, &index_key); - if (!IS_ERR(key_ref)) + key_ref = find_key_to_update(keyring_ref, &index_key); + if (key_ref) goto found_matching_key; } @@ -874,7 +873,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, } /* instantiate it and link it into the target keyring */ - ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &prealloc); + ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &edit); if (ret < 0) { key_put(key); key_ref = ERR_PTR(ret); @@ -884,7 +883,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, key_ref = make_key_ref(key, is_key_possessed(keyring_ref)); error_link_end: - __key_link_end(keyring, &index_key, prealloc); + __key_link_end(keyring, &index_key, edit); error_free_prep: if (index_key.type->preparse) index_key.type->free_preparse(&prep); @@ -897,7 +896,7 @@ error: /* we found a matching key, so we're going to try to update it * - we can drop the locks first as we have the key pinned */ - __key_link_end(keyring, &index_key, prealloc); + __key_link_end(keyring, &index_key, edit); key_ref = __key_update(key_ref, &prep); goto error_free_prep; diff --git a/security/keys/keyring.c b/security/keys/keyring.c index eeef1a073db..f7cdea22214 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -1,6 +1,6 @@ /* Keyring handling * - * Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved. + * Copyright (C) 2004-2005, 2008, 2013 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or @@ -17,25 +17,11 @@ #include #include #include +#include +#include #include #include "internal.h" -#define rcu_dereference_locked_keyring(keyring) \ - (rcu_dereference_protected( \ - (keyring)->payload.subscriptions, \ - rwsem_is_locked((struct rw_semaphore *)&(keyring)->sem))) - -#define rcu_deref_link_locked(klist, index, keyring) \ - (rcu_dereference_protected( \ - (klist)->keys[index], \ - rwsem_is_locked((struct rw_semaphore *)&(keyring)->sem))) - -#define MAX_KEYRING_LINKS \ - min_t(size_t, USHRT_MAX - 1, \ - ((PAGE_SIZE - sizeof(struct keyring_list)) / sizeof(struct key *))) - -#define KEY_LINK_FIXQUOTA 1UL - /* * When plumbing the depths of the key tree, this sets a hard limit * set on how deep we're willing to go. @@ -47,6 +33,28 @@ */ #define KEYRING_NAME_HASH_SIZE (1 << 5) +/* + * We mark pointers we pass to the associative array with bit 1 set if + * they're keyrings and clear otherwise. + */ +#define KEYRING_PTR_SUBTYPE 0x2UL + +static inline bool keyring_ptr_is_keyring(const struct assoc_array_ptr *x) +{ + return (unsigned long)x & KEYRING_PTR_SUBTYPE; +} +static inline struct key *keyring_ptr_to_key(const struct assoc_array_ptr *x) +{ + void *object = assoc_array_ptr_to_leaf(x); + return (struct key *)((unsigned long)object & ~KEYRING_PTR_SUBTYPE); +} +static inline void *keyring_key_to_ptr(struct key *key) +{ + if (key->type == &key_type_keyring) + return (void *)((unsigned long)key | KEYRING_PTR_SUBTYPE); + return key; +} + static struct list_head keyring_name_hash[KEYRING_NAME_HASH_SIZE]; static DEFINE_RWLOCK(keyring_name_lock); @@ -67,7 +75,6 @@ static inline unsigned keyring_hash(const char *desc) */ static int keyring_instantiate(struct key *keyring, struct key_preparsed_payload *prep); -static int keyring_match(const struct key *keyring, const void *criterion); static void keyring_revoke(struct key *keyring); static void keyring_destroy(struct key *keyring); static void keyring_describe(const struct key *keyring, struct seq_file *m); @@ -76,9 +83,9 @@ static long keyring_read(const struct key *keyring, struct key_type key_type_keyring = { .name = "keyring", - .def_datalen = sizeof(struct keyring_list), + .def_datalen = 0, .instantiate = keyring_instantiate, - .match = keyring_match, + .match = user_match, .revoke = keyring_revoke, .destroy = keyring_destroy, .describe = keyring_describe, @@ -127,6 +134,7 @@ static int keyring_instantiate(struct key *keyring, ret = -EINVAL; if (prep->datalen == 0) { + assoc_array_init(&keyring->keys); /* make the keyring available by name if it has one */ keyring_publish_name(keyring); ret = 0; @@ -136,14 +144,225 @@ static int keyring_instantiate(struct key *keyring, } /* - * Match keyrings on their name + * Multiply 64-bits by 32-bits to 96-bits and fold back to 64-bit. Ideally we'd + * fold the carry back too, but that requires inline asm. + */ +static u64 mult_64x32_and_fold(u64 x, u32 y) +{ + u64 hi = (u64)(u32)(x >> 32) * y; + u64 lo = (u64)(u32)(x) * y; + return lo + ((u64)(u32)hi << 32) + (u32)(hi >> 32); +} + +/* + * Hash a key type and description. + */ +static unsigned long hash_key_type_and_desc(const struct keyring_index_key *index_key) +{ + const unsigned level_shift = ASSOC_ARRAY_LEVEL_STEP; + const unsigned long level_mask = ASSOC_ARRAY_LEVEL_STEP_MASK; + const char *description = index_key->description; + unsigned long hash, type; + u32 piece; + u64 acc; + int n, desc_len = index_key->desc_len; + + type = (unsigned long)index_key->type; + + acc = mult_64x32_and_fold(type, desc_len + 13); + acc = mult_64x32_and_fold(acc, 9207); + for (;;) { + n = desc_len; + if (n <= 0) + break; + if (n > 4) + n = 4; + piece = 0; + memcpy(&piece, description, n); + description += n; + desc_len -= n; + acc = mult_64x32_and_fold(acc, piece); + acc = mult_64x32_and_fold(acc, 9207); + } + + /* Fold the hash down to 32 bits if need be. */ + hash = acc; + if (ASSOC_ARRAY_KEY_CHUNK_SIZE == 32) + hash ^= acc >> 32; + + /* Squidge all the keyrings into a separate part of the tree to + * ordinary keys by making sure the lowest level segment in the hash is + * zero for keyrings and non-zero otherwise. + */ + if (index_key->type != &key_type_keyring && (hash & level_mask) == 0) + return hash | (hash >> (ASSOC_ARRAY_KEY_CHUNK_SIZE - level_shift)) | 1; + if (index_key->type == &key_type_keyring && (hash & level_mask) != 0) + return (hash + (hash << level_shift)) & ~level_mask; + return hash; +} + +/* + * Build the next index key chunk. + * + * On 32-bit systems the index key is laid out as: + * + * 0 4 5 9... + * hash desclen typeptr desc[] + * + * On 64-bit systems: + * + * 0 8 9 17... + * hash desclen typeptr desc[] + * + * We return it one word-sized chunk at a time. */ -static int keyring_match(const struct key *keyring, const void *description) +static unsigned long keyring_get_key_chunk(const void *data, int level) +{ + const struct keyring_index_key *index_key = data; + unsigned long chunk = 0; + long offset = 0; + int desc_len = index_key->desc_len, n = sizeof(chunk); + + level /= ASSOC_ARRAY_KEY_CHUNK_SIZE; + switch (level) { + case 0: + return hash_key_type_and_desc(index_key); + case 1: + return ((unsigned long)index_key->type << 8) | desc_len; + case 2: + if (desc_len == 0) + return (u8)((unsigned long)index_key->type >> + (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8)); + n--; + offset = 1; + default: + offset += sizeof(chunk) - 1; + offset += (level - 3) * sizeof(chunk); + if (offset >= desc_len) + return 0; + desc_len -= offset; + if (desc_len > n) + desc_len = n; + offset += desc_len; + do { + chunk <<= 8; + chunk |= ((u8*)index_key->description)[--offset]; + } while (--desc_len > 0); + + if (level == 2) { + chunk <<= 8; + chunk |= (u8)((unsigned long)index_key->type >> + (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8)); + } + return chunk; + } +} + +static unsigned long keyring_get_object_key_chunk(const void *object, int level) +{ + const struct key *key = keyring_ptr_to_key(object); + return keyring_get_key_chunk(&key->index_key, level); +} + +static bool keyring_compare_object(const void *object, const void *data) { - return keyring->description && - strcmp(keyring->description, description) == 0; + const struct keyring_index_key *index_key = data; + const struct key *key = keyring_ptr_to_key(object); + + return key->index_key.type == index_key->type && + key->index_key.desc_len == index_key->desc_len && + memcmp(key->index_key.description, index_key->description, + index_key->desc_len) == 0; } +/* + * Compare the index keys of a pair of objects and determine the bit position + * at which they differ - if they differ. + */ +static int keyring_diff_objects(const void *_a, const void *_b) +{ + const struct key *key_a = keyring_ptr_to_key(_a); + const struct key *key_b = keyring_ptr_to_key(_b); + const struct keyring_index_key *a = &key_a->index_key; + const struct keyring_index_key *b = &key_b->index_key; + unsigned long seg_a, seg_b; + int level, i; + + level = 0; + seg_a = hash_key_type_and_desc(a); + seg_b = hash_key_type_and_desc(b); + if ((seg_a ^ seg_b) != 0) + goto differ; + + /* The number of bits contributed by the hash is controlled by a + * constant in the assoc_array headers. Everything else thereafter we + * can deal with as being machine word-size dependent. + */ + level += ASSOC_ARRAY_KEY_CHUNK_SIZE / 8; + seg_a = a->desc_len; + seg_b = b->desc_len; + if ((seg_a ^ seg_b) != 0) + goto differ; + + /* The next bit may not work on big endian */ + level++; + seg_a = (unsigned long)a->type; + seg_b = (unsigned long)b->type; + if ((seg_a ^ seg_b) != 0) + goto differ; + + level += sizeof(unsigned long); + if (a->desc_len == 0) + goto same; + + i = 0; + if (((unsigned long)a->description | (unsigned long)b->description) & + (sizeof(unsigned long) - 1)) { + do { + seg_a = *(unsigned long *)(a->description + i); + seg_b = *(unsigned long *)(b->description + i); + if ((seg_a ^ seg_b) != 0) + goto differ_plus_i; + i += sizeof(unsigned long); + } while (i < (a->desc_len & (sizeof(unsigned long) - 1))); + } + + for (; i < a->desc_len; i++) { + seg_a = *(unsigned char *)(a->description + i); + seg_b = *(unsigned char *)(b->description + i); + if ((seg_a ^ seg_b) != 0) + goto differ_plus_i; + } + +same: + return -1; + +differ_plus_i: + level += i; +differ: + i = level * 8 + __ffs(seg_a ^ seg_b); + return i; +} + +/* + * Free an object after stripping the keyring flag off of the pointer. + */ +static void keyring_free_object(void *object) +{ + key_put(keyring_ptr_to_key(object)); +} + +/* + * Operations for keyring management by the index-tree routines. + */ +static const struct assoc_array_ops keyring_assoc_array_ops = { + .get_key_chunk = keyring_get_key_chunk, + .get_object_key_chunk = keyring_get_object_key_chunk, + .compare_object = keyring_compare_object, + .diff_objects = keyring_diff_objects, + .free_object = keyring_free_object, +}; + /* * Clean up a keyring when it is destroyed. Unpublish its name if it had one * and dispose of its data. @@ -155,9 +374,6 @@ static int keyring_match(const struct key *keyring, const void *description) */ static void keyring_destroy(struct key *keyring) { - struct keyring_list *klist; - int loop; - if (keyring->description) { write_lock(&keyring_name_lock); @@ -168,12 +384,7 @@ static void keyring_destroy(struct key *keyring) write_unlock(&keyring_name_lock); } - klist = rcu_access_pointer(keyring->payload.subscriptions); - if (klist) { - for (loop = klist->nkeys - 1; loop >= 0; loop--) - key_put(rcu_access_pointer(klist->keys[loop])); - kfree(klist); - } + assoc_array_destroy(&keyring->keys, &keyring_assoc_array_ops); } /* @@ -181,76 +392,88 @@ static void keyring_destroy(struct key *keyring) */ static void keyring_describe(const struct key *keyring, struct seq_file *m) { - struct keyring_list *klist; - if (keyring->description) seq_puts(m, keyring->description); else seq_puts(m, "[anon]"); if (key_is_instantiated(keyring)) { - rcu_read_lock(); - klist = rcu_dereference(keyring->payload.subscriptions); - if (klist) - seq_printf(m, ": %u/%u", klist->nkeys, klist->maxkeys); + if (keyring->keys.nr_leaves_on_tree != 0) + seq_printf(m, ": %lu", keyring->keys.nr_leaves_on_tree); else seq_puts(m, ": empty"); - rcu_read_unlock(); } } +struct keyring_read_iterator_context { + size_t qty; + size_t count; + key_serial_t __user *buffer; +}; + +static int keyring_read_iterator(const void *object, void *data) +{ + struct keyring_read_iterator_context *ctx = data; + const struct key *key = keyring_ptr_to_key(object); + int ret; + + kenter("{%s,%d},,{%zu/%zu}", + key->type->name, key->serial, ctx->count, ctx->qty); + + if (ctx->count >= ctx->qty) + return 1; + + ret = put_user(key->serial, ctx->buffer); + if (ret < 0) + return ret; + ctx->buffer++; + ctx->count += sizeof(key->serial); + return 0; +} + /* * Read a list of key IDs from the keyring's contents in binary form * - * The keyring's semaphore is read-locked by the caller. + * The keyring's semaphore is read-locked by the caller. This prevents someone + * from modifying it under us - which could cause us to read key IDs multiple + * times. */ static long keyring_read(const struct key *keyring, char __user *buffer, size_t buflen) { - struct keyring_list *klist; - struct key *key; - size_t qty, tmp; - int loop, ret; + struct keyring_read_iterator_context ctx; + unsigned long nr_keys; + int ret; - ret = 0; - klist = rcu_dereference_locked_keyring(keyring); - if (klist) { - /* calculate how much data we could return */ - qty = klist->nkeys * sizeof(key_serial_t); - - if (buffer && buflen > 0) { - if (buflen > qty) - buflen = qty; - - /* copy the IDs of the subscribed keys into the - * buffer */ - ret = -EFAULT; - - for (loop = 0; loop < klist->nkeys; loop++) { - key = rcu_deref_link_locked(klist, loop, - keyring); - - tmp = sizeof(key_serial_t); - if (tmp > buflen) - tmp = buflen; - - if (copy_to_user(buffer, - &key->serial, - tmp) != 0) - goto error; - - buflen -= tmp; - if (buflen == 0) - break; - buffer += tmp; - } - } + kenter("{%d},,%zu", key_serial(keyring), buflen); + + if (buflen & (sizeof(key_serial_t) - 1)) + return -EINVAL; + + nr_keys = keyring->keys.nr_leaves_on_tree; + if (nr_keys == 0) + return 0; - ret = qty; + /* Calculate how much data we could return */ + ctx.qty = nr_keys * sizeof(key_serial_t); + + if (!buffer || !buflen) + return ctx.qty; + + if (buflen > ctx.qty) + ctx.qty = buflen; + + /* Copy the IDs of the subscribed keys into the buffer */ + ctx.buffer = (key_serial_t __user *)buffer; + ctx.count = 0; + ret = assoc_array_iterate(&keyring->keys, keyring_read_iterator, &ctx); + if (ret < 0) { + kleave(" = %d [iterate]", ret); + return ret; } -error: - return ret; + kleave(" = %zu [ok]", ctx.count); + return ctx.count; } /* @@ -277,219 +500,360 @@ struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, } EXPORT_SYMBOL(keyring_alloc); -/** - * keyring_search_aux - Search a keyring tree for a key matching some criteria - * @keyring_ref: A pointer to the keyring with possession indicator. - * @ctx: The keyring search context. - * - * Search the supplied keyring tree for a key that matches the criteria given. - * The root keyring and any linked keyrings must grant Search permission to the - * caller to be searchable and keys can only be found if they too grant Search - * to the caller. The possession flag on the root keyring pointer controls use - * of the possessor bits in permissions checking of the entire tree. In - * addition, the LSM gets to forbid keyring searches and key matches. - * - * The search is performed as a breadth-then-depth search up to the prescribed - * limit (KEYRING_SEARCH_MAX_DEPTH). - * - * Keys are matched to the type provided and are then filtered by the match - * function, which is given the description to use in any way it sees fit. The - * match function may use any attributes of a key that it wishes to to - * determine the match. Normally the match function from the key type would be - * used. - * - * RCU is used to prevent the keyring key lists from disappearing without the - * need to take lots of locks. - * - * Returns a pointer to the found key and increments the key usage count if - * successful; -EAGAIN if no matching keys were found, or if expired or revoked - * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the - * specified keyring wasn't a keyring. - * - * In the case of a successful return, the possession attribute from - * @keyring_ref is propagated to the returned key reference. +/* + * Iteration function to consider each key found. */ -key_ref_t keyring_search_aux(key_ref_t keyring_ref, - struct keyring_search_context *ctx) +static int keyring_search_iterator(const void *object, void *iterator_data) { - struct { - /* Need a separate keylist pointer for RCU purposes */ - struct key *keyring; - struct keyring_list *keylist; - int kix; - } stack[KEYRING_SEARCH_MAX_DEPTH]; - - struct keyring_list *keylist; - unsigned long kflags; - struct key *keyring, *key; - key_ref_t key_ref; - long err; - int sp, nkeys, kix; + struct keyring_search_context *ctx = iterator_data; + const struct key *key = keyring_ptr_to_key(object); + unsigned long kflags = key->flags; - keyring = key_ref_to_ptr(keyring_ref); - ctx->possessed = is_key_possessed(keyring_ref); - key_check(keyring); + kenter("{%d}", key->serial); - /* top keyring must have search permission to begin the search */ - err = key_task_permission(keyring_ref, ctx->cred, KEY_SEARCH); - if (err < 0) { - key_ref = ERR_PTR(err); - goto error; + /* ignore keys not of this type */ + if (key->type != ctx->index_key.type) { + kleave(" = 0 [!type]"); + return 0; } - key_ref = ERR_PTR(-ENOTDIR); - if (keyring->type != &key_type_keyring) - goto error; + /* skip invalidated, revoked and expired keys */ + if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { + if (kflags & ((1 << KEY_FLAG_INVALIDATED) | + (1 << KEY_FLAG_REVOKED))) { + ctx->result = ERR_PTR(-EKEYREVOKED); + kleave(" = %d [invrev]", ctx->skipped_ret); + goto skipped; + } - rcu_read_lock(); + if (key->expiry && ctx->now.tv_sec >= key->expiry) { + ctx->result = ERR_PTR(-EKEYEXPIRED); + kleave(" = %d [expire]", ctx->skipped_ret); + goto skipped; + } + } - ctx->now = current_kernel_time(); - err = -EAGAIN; - sp = 0; - - /* firstly we should check to see if this top-level keyring is what we - * are looking for */ - key_ref = ERR_PTR(-EAGAIN); - kflags = keyring->flags; - if (keyring->type == ctx->index_key.type && - ctx->match(keyring, ctx->match_data)) { - key = keyring; - if (ctx->flags & KEYRING_SEARCH_NO_STATE_CHECK) - goto found; + /* keys that don't match */ + if (!ctx->match(key, ctx->match_data)) { + kleave(" = 0 [!match]"); + return 0; + } - /* check it isn't negative and hasn't expired or been - * revoked */ - if (kflags & (1 << KEY_FLAG_REVOKED)) - goto error_2; - if (key->expiry && ctx->now.tv_sec >= key->expiry) - goto error_2; - key_ref = ERR_PTR(key->type_data.reject_error); - if (kflags & (1 << KEY_FLAG_NEGATIVE)) - goto error_2; - goto found; + /* key must have search permissions */ + if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && + key_task_permission(make_key_ref(key, ctx->possessed), + ctx->cred, KEY_SEARCH) < 0) { + ctx->result = ERR_PTR(-EACCES); + kleave(" = %d [!perm]", ctx->skipped_ret); + goto skipped; } - /* otherwise, the top keyring must not be revoked, expired, or - * negatively instantiated if we are to search it */ - key_ref = ERR_PTR(-EAGAIN); - if (kflags & ((1 << KEY_FLAG_INVALIDATED) | - (1 << KEY_FLAG_REVOKED) | - (1 << KEY_FLAG_NEGATIVE)) || - (keyring->expiry && ctx->now.tv_sec >= keyring->expiry)) - goto error_2; - - /* start processing a new keyring */ -descend: - kflags = keyring->flags; - if (kflags & ((1 << KEY_FLAG_INVALIDATED) | - (1 << KEY_FLAG_REVOKED))) - goto not_this_keyring; + if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { + /* we set a different error code if we pass a negative key */ + if (kflags & (1 << KEY_FLAG_NEGATIVE)) { + ctx->result = ERR_PTR(key->type_data.reject_error); + kleave(" = %d [neg]", ctx->skipped_ret); + goto skipped; + } + } - keylist = rcu_dereference(keyring->payload.subscriptions); - if (!keylist) - goto not_this_keyring; + /* Found */ + ctx->result = make_key_ref(key, ctx->possessed); + kleave(" = 1 [found]"); + return 1; - /* iterate through the keys in this keyring first */ - nkeys = keylist->nkeys; - smp_rmb(); - for (kix = 0; kix < nkeys; kix++) { - key = rcu_dereference(keylist->keys[kix]); - kflags = key->flags; +skipped: + return ctx->skipped_ret; +} - /* ignore keys not of this type */ - if (key->type != ctx->index_key.type) - continue; +/* + * Search inside a keyring for a key. We can search by walking to it + * directly based on its index-key or we can iterate over the entire + * tree looking for it, based on the match function. + */ +static int search_keyring(struct key *keyring, struct keyring_search_context *ctx) +{ + if ((ctx->flags & KEYRING_SEARCH_LOOKUP_TYPE) == + KEYRING_SEARCH_LOOKUP_DIRECT) { + const void *object; + + object = assoc_array_find(&keyring->keys, + &keyring_assoc_array_ops, + &ctx->index_key); + return object ? ctx->iterator(object, ctx) : 0; + } + return assoc_array_iterate(&keyring->keys, ctx->iterator, ctx); +} - /* skip invalidated, revoked and expired keys */ - if (!(ctx->flags & KEYRING_SEARCH_NO_STATE_CHECK)) { - if (kflags & ((1 << KEY_FLAG_INVALIDATED) | - (1 << KEY_FLAG_REVOKED))) - continue; +/* + * Search a tree of keyrings that point to other keyrings up to the maximum + * depth. + */ +static bool search_nested_keyrings(struct key *keyring, + struct keyring_search_context *ctx) +{ + struct { + struct key *keyring; + struct assoc_array_node *node; + int slot; + } stack[KEYRING_SEARCH_MAX_DEPTH]; - if (key->expiry && ctx->now.tv_sec >= key->expiry) - continue; - } + struct assoc_array_shortcut *shortcut; + struct assoc_array_node *node; + struct assoc_array_ptr *ptr; + struct key *key; + int sp = 0, slot; - /* keys that don't match */ - if (!ctx->match(key, ctx->match_data)) - continue; + kenter("{%d},{%s,%s}", + keyring->serial, + ctx->index_key.type->name, + ctx->index_key.description); - /* key must have search permissions */ - if (key_task_permission(make_key_ref(key, ctx->possessed), - ctx->cred, KEY_SEARCH) < 0) - continue; + if (ctx->index_key.description) + ctx->index_key.desc_len = strlen(ctx->index_key.description); - if (ctx->flags & KEYRING_SEARCH_NO_STATE_CHECK) + /* Check to see if this top-level keyring is what we are looking for + * and whether it is valid or not. + */ + if (ctx->flags & KEYRING_SEARCH_LOOKUP_ITERATE || + keyring_compare_object(keyring, &ctx->index_key)) { + ctx->skipped_ret = 2; + ctx->flags |= KEYRING_SEARCH_DO_STATE_CHECK; + switch (ctx->iterator(keyring_key_to_ptr(keyring), ctx)) { + case 1: goto found; - - /* we set a different error code if we pass a negative key */ - if (kflags & (1 << KEY_FLAG_NEGATIVE)) { - err = key->type_data.reject_error; - continue; + case 2: + return false; + default: + break; } + } + ctx->skipped_ret = 0; + if (ctx->flags & KEYRING_SEARCH_NO_STATE_CHECK) + ctx->flags &= ~KEYRING_SEARCH_DO_STATE_CHECK; + + /* Start processing a new keyring */ +descend_to_keyring: + kdebug("descend to %d", keyring->serial); + if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | + (1 << KEY_FLAG_REVOKED))) + goto not_this_keyring; + + /* Search through the keys in this keyring before its searching its + * subtrees. + */ + if (search_keyring(keyring, ctx)) goto found; - } - /* search through the keyrings nested in this one */ - kix = 0; -ascend: - nkeys = keylist->nkeys; - smp_rmb(); - for (; kix < nkeys; kix++) { - key = rcu_dereference(keylist->keys[kix]); - if (key->type != &key_type_keyring) - continue; + /* Then manually iterate through the keyrings nested in this one. + * + * Start from the root node of the index tree. Because of the way the + * hash function has been set up, keyrings cluster on the leftmost + * branch of the root node (root slot 0) or in the root node itself. + * Non-keyrings avoid the leftmost branch of the root entirely (root + * slots 1-15). + */ + ptr = ACCESS_ONCE(keyring->keys.root); + if (!ptr) + goto not_this_keyring; - /* recursively search nested keyrings - * - only search keyrings for which we have search permission + if (assoc_array_ptr_is_shortcut(ptr)) { + /* If the root is a shortcut, either the keyring only contains + * keyring pointers (everything clusters behind root slot 0) or + * doesn't contain any keyring pointers. */ - if (sp >= KEYRING_SEARCH_MAX_DEPTH) + shortcut = assoc_array_ptr_to_shortcut(ptr); + smp_read_barrier_depends(); + if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0) + goto not_this_keyring; + + ptr = ACCESS_ONCE(shortcut->next_node); + node = assoc_array_ptr_to_node(ptr); + goto begin_node; + } + + node = assoc_array_ptr_to_node(ptr); + smp_read_barrier_depends(); + + ptr = node->slots[0]; + if (!assoc_array_ptr_is_meta(ptr)) + goto begin_node; + +descend_to_node: + /* Descend to a more distal node in this keyring's content tree and go + * through that. + */ + kdebug("descend"); + if (assoc_array_ptr_is_shortcut(ptr)) { + shortcut = assoc_array_ptr_to_shortcut(ptr); + smp_read_barrier_depends(); + ptr = ACCESS_ONCE(shortcut->next_node); + BUG_ON(!assoc_array_ptr_is_node(ptr)); + node = assoc_array_ptr_to_node(ptr); + } + +begin_node: + kdebug("begin_node"); + smp_read_barrier_depends(); + slot = 0; +ascend_to_node: + /* Go through the slots in a node */ + for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) { + ptr = ACCESS_ONCE(node->slots[slot]); + + if (assoc_array_ptr_is_meta(ptr) && node->back_pointer) + goto descend_to_node; + + if (!keyring_ptr_is_keyring(ptr)) continue; - if (key_task_permission(make_key_ref(key, ctx->possessed), + key = keyring_ptr_to_key(ptr); + + if (sp >= KEYRING_SEARCH_MAX_DEPTH) { + if (ctx->flags & KEYRING_SEARCH_DETECT_TOO_DEEP) { + ctx->result = ERR_PTR(-ELOOP); + return false; + } + goto not_this_keyring; + } + + /* Search a nested keyring */ + if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && + key_task_permission(make_key_ref(key, ctx->possessed), ctx->cred, KEY_SEARCH) < 0) continue; /* stack the current position */ stack[sp].keyring = keyring; - stack[sp].keylist = keylist; - stack[sp].kix = kix; + stack[sp].node = node; + stack[sp].slot = slot; sp++; /* begin again with the new keyring */ keyring = key; - goto descend; + goto descend_to_keyring; + } + + /* We've dealt with all the slots in the current node, so now we need + * to ascend to the parent and continue processing there. + */ + ptr = ACCESS_ONCE(node->back_pointer); + slot = node->parent_slot; + + if (ptr && assoc_array_ptr_is_shortcut(ptr)) { + shortcut = assoc_array_ptr_to_shortcut(ptr); + smp_read_barrier_depends(); + ptr = ACCESS_ONCE(shortcut->back_pointer); + slot = shortcut->parent_slot; + } + if (!ptr) + goto not_this_keyring; + node = assoc_array_ptr_to_node(ptr); + smp_read_barrier_depends(); + slot++; + + /* If we've ascended to the root (zero backpointer), we must have just + * finished processing the leftmost branch rather than the root slots - + * so there can't be any more keyrings for us to find. + */ + if (node->back_pointer) { + kdebug("ascend %d", slot); + goto ascend_to_node; } - /* the keyring we're looking at was disqualified or didn't contain a - * matching key */ + /* The keyring we're looking at was disqualified or didn't contain a + * matching key. + */ not_this_keyring: - if (sp > 0) { - /* resume the processing of a keyring higher up in the tree */ - sp--; - keyring = stack[sp].keyring; - keylist = stack[sp].keylist; - kix = stack[sp].kix + 1; - goto ascend; + kdebug("not_this_keyring %d", sp); + if (sp <= 0) { + kleave(" = false"); + return false; } - key_ref = ERR_PTR(err); - goto error_2; + /* Resume the processing of a keyring higher up in the tree */ + sp--; + keyring = stack[sp].keyring; + node = stack[sp].node; + slot = stack[sp].slot + 1; + kdebug("ascend to %d [%d]", keyring->serial, slot); + goto ascend_to_node; - /* we found a viable match */ + /* We found a viable match */ found: - __key_get(key); - key->last_used_at = ctx->now.tv_sec; - keyring->last_used_at = ctx->now.tv_sec; - while (sp > 0) - stack[--sp].keyring->last_used_at = ctx->now.tv_sec; + key = key_ref_to_ptr(ctx->result); key_check(key); - key_ref = make_key_ref(key, ctx->possessed); -error_2: + if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) { + key->last_used_at = ctx->now.tv_sec; + keyring->last_used_at = ctx->now.tv_sec; + while (sp > 0) + stack[--sp].keyring->last_used_at = ctx->now.tv_sec; + } + kleave(" = true"); + return true; +} + +/** + * keyring_search_aux - Search a keyring tree for a key matching some criteria + * @keyring_ref: A pointer to the keyring with possession indicator. + * @ctx: The keyring search context. + * + * Search the supplied keyring tree for a key that matches the criteria given. + * The root keyring and any linked keyrings must grant Search permission to the + * caller to be searchable and keys can only be found if they too grant Search + * to the caller. The possession flag on the root keyring pointer controls use + * of the possessor bits in permissions checking of the entire tree. In + * addition, the LSM gets to forbid keyring searches and key matches. + * + * The search is performed as a breadth-then-depth search up to the prescribed + * limit (KEYRING_SEARCH_MAX_DEPTH). + * + * Keys are matched to the type provided and are then filtered by the match + * function, which is given the description to use in any way it sees fit. The + * match function may use any attributes of a key that it wishes to to + * determine the match. Normally the match function from the key type would be + * used. + * + * RCU can be used to prevent the keyring key lists from disappearing without + * the need to take lots of locks. + * + * Returns a pointer to the found key and increments the key usage count if + * successful; -EAGAIN if no matching keys were found, or if expired or revoked + * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the + * specified keyring wasn't a keyring. + * + * In the case of a successful return, the possession attribute from + * @keyring_ref is propagated to the returned key reference. + */ +key_ref_t keyring_search_aux(key_ref_t keyring_ref, + struct keyring_search_context *ctx) +{ + struct key *keyring; + long err; + + ctx->iterator = keyring_search_iterator; + ctx->possessed = is_key_possessed(keyring_ref); + ctx->result = ERR_PTR(-EAGAIN); + + keyring = key_ref_to_ptr(keyring_ref); + key_check(keyring); + + if (keyring->type != &key_type_keyring) + return ERR_PTR(-ENOTDIR); + + if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM)) { + err = key_task_permission(keyring_ref, ctx->cred, KEY_SEARCH); + if (err < 0) + return ERR_PTR(err); + } + + rcu_read_lock(); + ctx->now = current_kernel_time(); + if (search_nested_keyrings(keyring, ctx)) + __key_get(key_ref_to_ptr(ctx->result)); rcu_read_unlock(); -error: - return key_ref; + return ctx->result; } /** @@ -499,7 +863,7 @@ error: * @description: The name of the keyring we want to find. * * As keyring_search_aux() above, but using the current task's credentials and - * type's default matching function. + * type's default matching function and preferred search method. */ key_ref_t keyring_search(key_ref_t keyring, struct key_type *type, @@ -523,58 +887,49 @@ key_ref_t keyring_search(key_ref_t keyring, EXPORT_SYMBOL(keyring_search); /* - * Search the given keyring only (no recursion). + * Search the given keyring for a key that might be updated. * * The caller must guarantee that the keyring is a keyring and that the - * permission is granted to search the keyring as no check is made here. - * - * RCU is used to make it unnecessary to lock the keyring key list here. + * permission is granted to modify the keyring as no check is made here. The + * caller must also hold a lock on the keyring semaphore. * * Returns a pointer to the found key with usage count incremented if - * successful and returns -ENOKEY if not found. Revoked and invalidated keys - * are skipped over. + * successful and returns NULL if not found. Revoked and invalidated keys are + * skipped over. * * If successful, the possession indicator is propagated from the keyring ref * to the returned key reference. */ -key_ref_t __keyring_search_one(key_ref_t keyring_ref, - const struct keyring_index_key *index_key) +key_ref_t find_key_to_update(key_ref_t keyring_ref, + const struct keyring_index_key *index_key) { - struct keyring_list *klist; struct key *keyring, *key; - bool possessed; - int nkeys, loop; + const void *object; keyring = key_ref_to_ptr(keyring_ref); - possessed = is_key_possessed(keyring_ref); - rcu_read_lock(); + kenter("{%d},{%s,%s}", + keyring->serial, index_key->type->name, index_key->description); - klist = rcu_dereference(keyring->payload.subscriptions); - if (klist) { - nkeys = klist->nkeys; - smp_rmb(); - for (loop = 0; loop < nkeys ; loop++) { - key = rcu_dereference(klist->keys[loop]); - if (key->type == index_key->type && - (!key->type->match || - key->type->match(key, index_key->description)) && - !(key->flags & ((1 << KEY_FLAG_INVALIDATED) | - (1 << KEY_FLAG_REVOKED))) - ) - goto found; - } - } + object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops, + index_key); - rcu_read_unlock(); - return ERR_PTR(-ENOKEY); + if (object) + goto found; + + kleave(" = NULL"); + return NULL; found: + key = keyring_ptr_to_key(object); + if (key->flags & ((1 << KEY_FLAG_INVALIDATED) | + (1 << KEY_FLAG_REVOKED))) { + kleave(" = NULL [x]"); + return NULL; + } __key_get(key); - keyring->last_used_at = key->last_used_at = - current_kernel_time().tv_sec; - rcu_read_unlock(); - return make_key_ref(key, possessed); + kleave(" = {%d}", key->serial); + return make_key_ref(key, is_key_possessed(keyring_ref)); } /* @@ -637,6 +992,19 @@ out: return keyring; } +static int keyring_detect_cycle_iterator(const void *object, + void *iterator_data) +{ + struct keyring_search_context *ctx = iterator_data; + const struct key *key = keyring_ptr_to_key(object); + + kenter("{%d}", key->serial); + + BUG_ON(key != ctx->match_data); + ctx->result = ERR_PTR(-EDEADLK); + return 1; +} + /* * See if a cycle will will be created by inserting acyclic tree B in acyclic * tree A at the topmost level (ie: as a direct child of A). @@ -646,117 +1014,39 @@ out: */ static int keyring_detect_cycle(struct key *A, struct key *B) { - struct { - struct keyring_list *keylist; - int kix; - } stack[KEYRING_SEARCH_MAX_DEPTH]; - - struct keyring_list *keylist; - struct key *subtree, *key; - int sp, nkeys, kix, ret; + struct keyring_search_context ctx = { + .index_key = A->index_key, + .match_data = A, + .iterator = keyring_detect_cycle_iterator, + .flags = (KEYRING_SEARCH_LOOKUP_DIRECT | + KEYRING_SEARCH_NO_STATE_CHECK | + KEYRING_SEARCH_NO_UPDATE_TIME | + KEYRING_SEARCH_NO_CHECK_PERM | + KEYRING_SEARCH_DETECT_TOO_DEEP), + }; rcu_read_lock(); - - ret = -EDEADLK; - if (A == B) - goto cycle_detected; - - subtree = B; - sp = 0; - - /* start processing a new keyring */ -descend: - if (test_bit(KEY_FLAG_REVOKED, &subtree->flags)) - goto not_this_keyring; - - keylist = rcu_dereference(subtree->payload.subscriptions); - if (!keylist) - goto not_this_keyring; - kix = 0; - -ascend: - /* iterate through the remaining keys in this keyring */ - nkeys = keylist->nkeys; - smp_rmb(); - for (; kix < nkeys; kix++) { - key = rcu_dereference(keylist->keys[kix]); - - if (key == A) - goto cycle_detected; - - /* recursively check nested keyrings */ - if (key->type == &key_type_keyring) { - if (sp >= KEYRING_SEARCH_MAX_DEPTH) - goto too_deep; - - /* stack the current position */ - stack[sp].keylist = keylist; - stack[sp].kix = kix; - sp++; - - /* begin again with the new keyring */ - subtree = key; - goto descend; - } - } - - /* the keyring we're looking at was disqualified or didn't contain a - * matching key */ -not_this_keyring: - if (sp > 0) { - /* resume the checking of a keyring higher up in the tree */ - sp--; - keylist = stack[sp].keylist; - kix = stack[sp].kix + 1; - goto ascend; - } - - ret = 0; /* no cycles detected */ - -error: + search_nested_keyrings(B, &ctx); rcu_read_unlock(); - return ret; - -too_deep: - ret = -ELOOP; - goto error; - -cycle_detected: - ret = -EDEADLK; - goto error; -} - -/* - * Dispose of a keyring list after the RCU grace period, freeing the unlinked - * key - */ -static void keyring_unlink_rcu_disposal(struct rcu_head *rcu) -{ - struct keyring_list *klist = - container_of(rcu, struct keyring_list, rcu); - - if (klist->delkey != USHRT_MAX) - key_put(rcu_access_pointer(klist->keys[klist->delkey])); - kfree(klist); + return PTR_ERR(ctx.result) == -EAGAIN ? 0 : PTR_ERR(ctx.result); } /* * Preallocate memory so that a key can be linked into to a keyring. */ -int __key_link_begin(struct key *keyring, const struct keyring_index_key *index_key, - unsigned long *_prealloc) +int __key_link_begin(struct key *keyring, + const struct keyring_index_key *index_key, + struct assoc_array_edit **_edit) __acquires(&keyring->sem) __acquires(&keyring_serialise_link_sem) { - struct keyring_list *klist, *nklist; - unsigned long prealloc; - unsigned max; - time_t lowest_lru; - size_t size; - int loop, lru, ret; + struct assoc_array_edit *edit; + int ret; kenter("%d,%s,%s,", - key_serial(keyring), index_key->type->name, index_key->description); + keyring->serial, index_key->type->name, index_key->description); + + BUG_ON(index_key->desc_len == 0); if (keyring->type != &key_type_keyring) return -ENOTDIR; @@ -772,88 +1062,25 @@ int __key_link_begin(struct key *keyring, const struct keyring_index_key *index_ if (index_key->type == &key_type_keyring) down_write(&keyring_serialise_link_sem); - klist = rcu_dereference_locked_keyring(keyring); - - /* see if there's a matching key we can displace */ - lru = -1; - if (klist && klist->nkeys > 0) { - lowest_lru = TIME_T_MAX; - for (loop = klist->nkeys - 1; loop >= 0; loop--) { - struct key *key = rcu_deref_link_locked(klist, loop, - keyring); - if (key->type == index_key->type && - strcmp(key->description, index_key->description) == 0) { - /* Found a match - we'll replace the link with - * one to the new key. We record the slot - * position. - */ - klist->delkey = loop; - prealloc = 0; - goto done; - } - if (key->last_used_at < lowest_lru) { - lowest_lru = key->last_used_at; - lru = loop; - } - } - } - - /* If the keyring is full then do an LRU discard */ - if (klist && - klist->nkeys == klist->maxkeys && - klist->maxkeys >= MAX_KEYRING_LINKS) { - kdebug("LRU discard %d\n", lru); - klist->delkey = lru; - prealloc = 0; - goto done; - } - /* check that we aren't going to overrun the user's quota */ ret = key_payload_reserve(keyring, keyring->datalen + KEYQUOTA_LINK_BYTES); if (ret < 0) goto error_sem; - if (klist && klist->nkeys < klist->maxkeys) { - /* there's sufficient slack space to append directly */ - klist->delkey = klist->nkeys; - prealloc = KEY_LINK_FIXQUOTA; - } else { - /* grow the key list */ - max = 4; - if (klist) { - max += klist->maxkeys; - if (max > MAX_KEYRING_LINKS) - max = MAX_KEYRING_LINKS; - BUG_ON(max <= klist->maxkeys); - } - - size = sizeof(*klist) + sizeof(struct key *) * max; - - ret = -ENOMEM; - nklist = kmalloc(size, GFP_KERNEL); - if (!nklist) - goto error_quota; - - nklist->maxkeys = max; - if (klist) { - memcpy(nklist->keys, klist->keys, - sizeof(struct key *) * klist->nkeys); - nklist->delkey = klist->nkeys; - nklist->nkeys = klist->nkeys + 1; - klist->delkey = USHRT_MAX; - } else { - nklist->nkeys = 1; - nklist->delkey = 0; - } - - /* add the key into the new space */ - RCU_INIT_POINTER(nklist->keys[nklist->delkey], NULL); - prealloc = (unsigned long)nklist | KEY_LINK_FIXQUOTA; + /* Create an edit script that will insert/replace the key in the + * keyring tree. + */ + edit = assoc_array_insert(&keyring->keys, + &keyring_assoc_array_ops, + index_key, + NULL); + if (IS_ERR(edit)) { + ret = PTR_ERR(edit); + goto error_quota; } -done: - *_prealloc = prealloc; + *_edit = edit; kleave(" = 0"); return 0; @@ -893,60 +1120,12 @@ int __key_link_check_live_key(struct key *keyring, struct key *key) * holds at most one link to any given key of a particular type+description * combination. */ -void __key_link(struct key *keyring, struct key *key, - unsigned long *_prealloc) +void __key_link(struct key *key, struct assoc_array_edit **_edit) { - struct keyring_list *klist, *nklist; - struct key *discard; - - nklist = (struct keyring_list *)(*_prealloc & ~KEY_LINK_FIXQUOTA); - *_prealloc = 0; - - kenter("%d,%d,%p", keyring->serial, key->serial, nklist); - - klist = rcu_dereference_locked_keyring(keyring); - __key_get(key); - keyring->last_used_at = key->last_used_at = - current_kernel_time().tv_sec; - - /* there's a matching key we can displace or an empty slot in a newly - * allocated list we can fill */ - if (nklist) { - kdebug("reissue %hu/%hu/%hu", - nklist->delkey, nklist->nkeys, nklist->maxkeys); - - RCU_INIT_POINTER(nklist->keys[nklist->delkey], key); - - rcu_assign_pointer(keyring->payload.subscriptions, nklist); - - /* dispose of the old keyring list and, if there was one, the - * displaced key */ - if (klist) { - kdebug("dispose %hu/%hu/%hu", - klist->delkey, klist->nkeys, klist->maxkeys); - call_rcu(&klist->rcu, keyring_unlink_rcu_disposal); - } - } else if (klist->delkey < klist->nkeys) { - kdebug("replace %hu/%hu/%hu", - klist->delkey, klist->nkeys, klist->maxkeys); - - discard = rcu_dereference_protected( - klist->keys[klist->delkey], - rwsem_is_locked(&keyring->sem)); - rcu_assign_pointer(klist->keys[klist->delkey], key); - /* The garbage collector will take care of RCU - * synchronisation */ - key_put(discard); - } else { - /* there's sufficient slack space to append directly */ - kdebug("append %hu/%hu/%hu", - klist->delkey, klist->nkeys, klist->maxkeys); - - RCU_INIT_POINTER(klist->keys[klist->delkey], key); - smp_wmb(); - klist->nkeys++; - } + assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key)); + assoc_array_apply_edit(*_edit); + *_edit = NULL; } /* @@ -956,23 +1135,20 @@ void __key_link(struct key *keyring, struct key *key, */ void __key_link_end(struct key *keyring, const struct keyring_index_key *index_key, - unsigned long prealloc) + struct assoc_array_edit *edit) __releases(&keyring->sem) __releases(&keyring_serialise_link_sem) { BUG_ON(index_key->type == NULL); - BUG_ON(index_key->type->name == NULL); - kenter("%d,%s,%lx", keyring->serial, index_key->type->name, prealloc); + kenter("%d,%s,", keyring->serial, index_key->type->name); if (index_key->type == &key_type_keyring) up_write(&keyring_serialise_link_sem); - if (prealloc) { - if (prealloc & KEY_LINK_FIXQUOTA) - key_payload_reserve(keyring, - keyring->datalen - - KEYQUOTA_LINK_BYTES); - kfree((struct keyring_list *)(prealloc & ~KEY_LINK_FIXQUOTA)); + if (edit) { + key_payload_reserve(keyring, + keyring->datalen - KEYQUOTA_LINK_BYTES); + assoc_array_cancel_edit(edit); } up_write(&keyring->sem); } @@ -999,20 +1175,24 @@ void __key_link_end(struct key *keyring, */ int key_link(struct key *keyring, struct key *key) { - unsigned long prealloc; + struct assoc_array_edit *edit; int ret; + kenter("{%d,%d}", keyring->serial, atomic_read(&keyring->usage)); + key_check(keyring); key_check(key); - ret = __key_link_begin(keyring, &key->index_key, &prealloc); + ret = __key_link_begin(keyring, &key->index_key, &edit); if (ret == 0) { + kdebug("begun {%d,%d}", keyring->serial, atomic_read(&keyring->usage)); ret = __key_link_check_live_key(keyring, key); if (ret == 0) - __key_link(keyring, key, &prealloc); - __key_link_end(keyring, &key->index_key, prealloc); + __key_link(key, &edit); + __key_link_end(keyring, &key->index_key, edit); } + kleave(" = %d {%d,%d}", ret, keyring->serial, atomic_read(&keyring->usage)); return ret; } EXPORT_SYMBOL(key_link); @@ -1036,90 +1216,36 @@ EXPORT_SYMBOL(key_link); */ int key_unlink(struct key *keyring, struct key *key) { - struct keyring_list *klist, *nklist; - int loop, ret; + struct assoc_array_edit *edit; + int ret; key_check(keyring); key_check(key); - ret = -ENOTDIR; if (keyring->type != &key_type_keyring) - goto error; + return -ENOTDIR; down_write(&keyring->sem); - klist = rcu_dereference_locked_keyring(keyring); - if (klist) { - /* search the keyring for the key */ - for (loop = 0; loop < klist->nkeys; loop++) - if (rcu_access_pointer(klist->keys[loop]) == key) - goto key_is_present; + edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops, + &key->index_key); + if (IS_ERR(edit)) { + ret = PTR_ERR(edit); + goto error; } - - up_write(&keyring->sem); ret = -ENOENT; - goto error; - -key_is_present: - /* we need to copy the key list for RCU purposes */ - nklist = kmalloc(sizeof(*klist) + - sizeof(struct key *) * klist->maxkeys, - GFP_KERNEL); - if (!nklist) - goto nomem; - nklist->maxkeys = klist->maxkeys; - nklist->nkeys = klist->nkeys - 1; - - if (loop > 0) - memcpy(&nklist->keys[0], - &klist->keys[0], - loop * sizeof(struct key *)); - - if (loop < nklist->nkeys) - memcpy(&nklist->keys[loop], - &klist->keys[loop + 1], - (nklist->nkeys - loop) * sizeof(struct key *)); - - /* adjust the user's quota */ - key_payload_reserve(keyring, - keyring->datalen - KEYQUOTA_LINK_BYTES); - - rcu_assign_pointer(keyring->payload.subscriptions, nklist); - - up_write(&keyring->sem); - - /* schedule for later cleanup */ - klist->delkey = loop; - call_rcu(&klist->rcu, keyring_unlink_rcu_disposal); + if (edit == NULL) + goto error; + assoc_array_apply_edit(edit); ret = 0; error: - return ret; -nomem: - ret = -ENOMEM; up_write(&keyring->sem); - goto error; + return ret; } EXPORT_SYMBOL(key_unlink); -/* - * Dispose of a keyring list after the RCU grace period, releasing the keys it - * links to. - */ -static void keyring_clear_rcu_disposal(struct rcu_head *rcu) -{ - struct keyring_list *klist; - int loop; - - klist = container_of(rcu, struct keyring_list, rcu); - - for (loop = klist->nkeys - 1; loop >= 0; loop--) - key_put(rcu_access_pointer(klist->keys[loop])); - - kfree(klist); -} - /** * keyring_clear - Clear a keyring * @keyring: The keyring to clear. @@ -1130,33 +1256,25 @@ static void keyring_clear_rcu_disposal(struct rcu_head *rcu) */ int keyring_clear(struct key *keyring) { - struct keyring_list *klist; + struct assoc_array_edit *edit; int ret; - ret = -ENOTDIR; - if (keyring->type == &key_type_keyring) { - /* detach the pointer block with the locks held */ - down_write(&keyring->sem); - - klist = rcu_dereference_locked_keyring(keyring); - if (klist) { - /* adjust the quota */ - key_payload_reserve(keyring, - sizeof(struct keyring_list)); - - rcu_assign_pointer(keyring->payload.subscriptions, - NULL); - } - - up_write(&keyring->sem); + if (keyring->type != &key_type_keyring) + return -ENOTDIR; - /* free the keys after the locks have been dropped */ - if (klist) - call_rcu(&klist->rcu, keyring_clear_rcu_disposal); + down_write(&keyring->sem); + edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); + if (IS_ERR(edit)) { + ret = PTR_ERR(edit); + } else { + if (edit) + assoc_array_apply_edit(edit); + key_payload_reserve(keyring, 0); ret = 0; } + up_write(&keyring->sem); return ret; } EXPORT_SYMBOL(keyring_clear); @@ -1168,17 +1286,25 @@ EXPORT_SYMBOL(keyring_clear); */ static void keyring_revoke(struct key *keyring) { - struct keyring_list *klist; + struct assoc_array_edit *edit; - klist = rcu_dereference_locked_keyring(keyring); + edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); + if (!IS_ERR(edit)) { + if (edit) + assoc_array_apply_edit(edit); + key_payload_reserve(keyring, 0); + } +} - /* adjust the quota */ - key_payload_reserve(keyring, 0); +static bool gc_iterator(void *object, void *iterator_data) +{ + struct key *key = keyring_ptr_to_key(object); + time_t *limit = iterator_data; - if (klist) { - rcu_assign_pointer(keyring->payload.subscriptions, NULL); - call_rcu(&klist->rcu, keyring_clear_rcu_disposal); - } + if (key_is_dead(key, *limit)) + return false; + key_get(key); + return true; } /* @@ -1191,88 +1317,12 @@ static void keyring_revoke(struct key *keyring) */ void keyring_gc(struct key *keyring, time_t limit) { - struct keyring_list *klist, *new; - struct key *key; - int loop, keep, max; - kenter("{%x,%s}", key_serial(keyring), keyring->description); down_write(&keyring->sem); - - klist = rcu_dereference_locked_keyring(keyring); - if (!klist) - goto no_klist; - - /* work out how many subscriptions we're keeping */ - keep = 0; - for (loop = klist->nkeys - 1; loop >= 0; loop--) - if (!key_is_dead(rcu_deref_link_locked(klist, loop, keyring), - limit)) - keep++; - - if (keep == klist->nkeys) - goto just_return; - - /* allocate a new keyring payload */ - max = roundup(keep, 4); - new = kmalloc(sizeof(struct keyring_list) + max * sizeof(struct key *), - GFP_KERNEL); - if (!new) - goto nomem; - new->maxkeys = max; - new->nkeys = 0; - new->delkey = 0; - - /* install the live keys - * - must take care as expired keys may be updated back to life - */ - keep = 0; - for (loop = klist->nkeys - 1; loop >= 0; loop--) { - key = rcu_deref_link_locked(klist, loop, keyring); - if (!key_is_dead(key, limit)) { - if (keep >= max) - goto discard_new; - RCU_INIT_POINTER(new->keys[keep++], key_get(key)); - } - } - new->nkeys = keep; - - /* adjust the quota */ - key_payload_reserve(keyring, - sizeof(struct keyring_list) + - KEYQUOTA_LINK_BYTES * keep); - - if (keep == 0) { - rcu_assign_pointer(keyring->payload.subscriptions, NULL); - kfree(new); - } else { - rcu_assign_pointer(keyring->payload.subscriptions, new); - } - - up_write(&keyring->sem); - - call_rcu(&klist->rcu, keyring_clear_rcu_disposal); - kleave(" [yes]"); - return; - -discard_new: - new->nkeys = keep; - keyring_clear_rcu_disposal(&new->rcu); + assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops, + gc_iterator, &limit); up_write(&keyring->sem); - kleave(" [discard]"); - return; -just_return: - up_write(&keyring->sem); - kleave(" [no dead]"); - return; - -no_klist: - up_write(&keyring->sem); - kleave(" [no_klist]"); - return; - -nomem: - up_write(&keyring->sem); - kleave(" [oom]"); + kleave(""); } diff --git a/security/keys/request_key.c b/security/keys/request_key.c index ab75df4745a..df94827103d 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -351,7 +351,7 @@ static int construct_alloc_key(struct keyring_search_context *ctx, struct key_user *user, struct key **_key) { - unsigned long prealloc; + struct assoc_array_edit *edit; struct key *key; key_perm_t perm; key_ref_t key_ref; @@ -380,7 +380,7 @@ static int construct_alloc_key(struct keyring_search_context *ctx, set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags); if (dest_keyring) { - ret = __key_link_begin(dest_keyring, &ctx->index_key, &prealloc); + ret = __key_link_begin(dest_keyring, &ctx->index_key, &edit); if (ret < 0) goto link_prealloc_failed; } @@ -395,11 +395,11 @@ static int construct_alloc_key(struct keyring_search_context *ctx, goto key_already_present; if (dest_keyring) - __key_link(dest_keyring, key, &prealloc); + __key_link(key, &edit); mutex_unlock(&key_construction_mutex); if (dest_keyring) - __key_link_end(dest_keyring, &ctx->index_key, prealloc); + __key_link_end(dest_keyring, &ctx->index_key, edit); mutex_unlock(&user->cons_lock); *_key = key; kleave(" = 0 [%d]", key_serial(key)); @@ -414,8 +414,8 @@ key_already_present: if (dest_keyring) { ret = __key_link_check_live_key(dest_keyring, key); if (ret == 0) - __key_link(dest_keyring, key, &prealloc); - __key_link_end(dest_keyring, &ctx->index_key, prealloc); + __key_link(key, &edit); + __key_link_end(dest_keyring, &ctx->index_key, edit); if (ret < 0) goto link_check_failed; } -- cgit v1.2.3-70-g09d2 From ab3c3587f8cda9083209a61dbe3a4407d3cada10 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:18 +0100 Subject: KEYS: Implement a big key type that can save to tmpfs Implement a big key type that can save its contents to tmpfs and thus swapspace when memory is tight. This is useful for Kerberos ticket caches. Signed-off-by: David Howells Tested-by: Simo Sorce --- include/keys/big_key-type.h | 25 ++++++ include/linux/key.h | 1 + security/keys/Kconfig | 11 +++ security/keys/Makefile | 1 + security/keys/big_key.c | 204 ++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 242 insertions(+) create mode 100644 include/keys/big_key-type.h create mode 100644 security/keys/big_key.c (limited to 'security/keys') diff --git a/include/keys/big_key-type.h b/include/keys/big_key-type.h new file mode 100644 index 00000000000..d69bc8af329 --- /dev/null +++ b/include/keys/big_key-type.h @@ -0,0 +1,25 @@ +/* Big capacity key type. + * + * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#ifndef _KEYS_BIG_KEY_TYPE_H +#define _KEYS_BIG_KEY_TYPE_H + +#include + +extern struct key_type key_type_big_key; + +extern int big_key_instantiate(struct key *key, struct key_preparsed_payload *prep); +extern void big_key_revoke(struct key *key); +extern void big_key_destroy(struct key *key); +extern void big_key_describe(const struct key *big_key, struct seq_file *m); +extern long big_key_read(const struct key *key, char __user *buffer, size_t buflen); + +#endif /* _KEYS_BIG_KEY_TYPE_H */ diff --git a/include/linux/key.h b/include/linux/key.h index 2417f789d29..010dbb618ac 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -201,6 +201,7 @@ struct key { unsigned long value; void __rcu *rcudata; void *data; + void *data2[2]; } payload; struct assoc_array keys; }; diff --git a/security/keys/Kconfig b/security/keys/Kconfig index 15e0dfe8c80..b56362275ec 100644 --- a/security/keys/Kconfig +++ b/security/keys/Kconfig @@ -20,6 +20,17 @@ config KEYS If you are unsure as to whether this is required, answer N. +config BIG_KEYS + tristate "Large payload keys" + depends on KEYS + depends on TMPFS + help + This option provides support for holding large keys within the kernel + (for example Kerberos ticket caches). The data may be stored out to + swapspace by tmpfs. + + If you are unsure as to whether this is required, answer N. + config TRUSTED_KEYS tristate "TRUSTED KEYS" depends on KEYS && TCG_TPM diff --git a/security/keys/Makefile b/security/keys/Makefile index 504aaa00838..c487c77a00b 100644 --- a/security/keys/Makefile +++ b/security/keys/Makefile @@ -22,5 +22,6 @@ obj-$(CONFIG_SYSCTL) += sysctl.o # # Key types # +obj-$(CONFIG_BIG_KEYS) += big_key.o obj-$(CONFIG_TRUSTED_KEYS) += trusted.o obj-$(CONFIG_ENCRYPTED_KEYS) += encrypted-keys/ diff --git a/security/keys/big_key.c b/security/keys/big_key.c new file mode 100644 index 00000000000..5f9defc4a80 --- /dev/null +++ b/security/keys/big_key.c @@ -0,0 +1,204 @@ +/* Large capacity key type + * + * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +MODULE_LICENSE("GPL"); + +/* + * If the data is under this limit, there's no point creating a shm file to + * hold it as the permanently resident metadata for the shmem fs will be at + * least as large as the data. + */ +#define BIG_KEY_FILE_THRESHOLD (sizeof(struct inode) + sizeof(struct dentry)) + +/* + * big_key defined keys take an arbitrary string as the description and an + * arbitrary blob of data as the payload + */ +struct key_type key_type_big_key = { + .name = "big_key", + .def_lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, + .instantiate = big_key_instantiate, + .match = user_match, + .revoke = big_key_revoke, + .destroy = big_key_destroy, + .describe = big_key_describe, + .read = big_key_read, +}; + +/* + * Instantiate a big key + */ +int big_key_instantiate(struct key *key, struct key_preparsed_payload *prep) +{ + struct path *path = (struct path *)&key->payload.data2; + struct file *file; + ssize_t written; + size_t datalen = prep->datalen; + int ret; + + ret = -EINVAL; + if (datalen <= 0 || datalen > 1024 * 1024 || !prep->data) + goto error; + + /* Set an arbitrary quota */ + ret = key_payload_reserve(key, 16); + if (ret < 0) + goto error; + + key->type_data.x[1] = datalen; + + if (datalen > BIG_KEY_FILE_THRESHOLD) { + /* Create a shmem file to store the data in. This will permit the data + * to be swapped out if needed. + * + * TODO: Encrypt the stored data with a temporary key. + */ + file = shmem_file_setup("", datalen, 0); + if (IS_ERR(file)) + goto err_quota; + + written = kernel_write(file, prep->data, prep->datalen, 0); + if (written != datalen) { + if (written >= 0) + ret = -ENOMEM; + goto err_fput; + } + + /* Pin the mount and dentry to the key so that we can open it again + * later + */ + *path = file->f_path; + path_get(path); + fput(file); + } else { + /* Just store the data in a buffer */ + void *data = kmalloc(datalen, GFP_KERNEL); + if (!data) { + ret = -ENOMEM; + goto err_quota; + } + + key->payload.data = memcpy(data, prep->data, prep->datalen); + } + return 0; + +err_fput: + fput(file); +err_quota: + key_payload_reserve(key, 0); +error: + return ret; +} + +/* + * dispose of the links from a revoked keyring + * - called with the key sem write-locked + */ +void big_key_revoke(struct key *key) +{ + struct path *path = (struct path *)&key->payload.data2; + + /* clear the quota */ + key_payload_reserve(key, 0); + if (key_is_instantiated(key) && key->type_data.x[1] > BIG_KEY_FILE_THRESHOLD) + vfs_truncate(path, 0); +} + +/* + * dispose of the data dangling from the corpse of a big_key key + */ +void big_key_destroy(struct key *key) +{ + if (key->type_data.x[1] > BIG_KEY_FILE_THRESHOLD) { + struct path *path = (struct path *)&key->payload.data2; + path_put(path); + path->mnt = NULL; + path->dentry = NULL; + } else { + kfree(key->payload.data); + key->payload.data = NULL; + } +} + +/* + * describe the big_key key + */ +void big_key_describe(const struct key *key, struct seq_file *m) +{ + unsigned long datalen = key->type_data.x[1]; + + seq_puts(m, key->description); + + if (key_is_instantiated(key)) + seq_printf(m, ": %lu [%s]", + datalen, + datalen > BIG_KEY_FILE_THRESHOLD ? "file" : "buff"); +} + +/* + * read the key data + * - the key's semaphore is read-locked + */ +long big_key_read(const struct key *key, char __user *buffer, size_t buflen) +{ + unsigned long datalen = key->type_data.x[1]; + long ret; + + if (!buffer || buflen < datalen) + return datalen; + + if (datalen > BIG_KEY_FILE_THRESHOLD) { + struct path *path = (struct path *)&key->payload.data2; + struct file *file; + loff_t pos; + + file = dentry_open(path, O_RDONLY, current_cred()); + if (IS_ERR(file)) + return PTR_ERR(file); + + pos = 0; + ret = vfs_read(file, buffer, datalen, &pos); + fput(file); + if (ret >= 0 && ret != datalen) + ret = -EIO; + } else { + ret = datalen; + if (copy_to_user(buffer, key->payload.data, datalen) != 0) + ret = -EFAULT; + } + + return ret; +} + +/* + * Module stuff + */ +static int __init big_key_init(void) +{ + return register_key_type(&key_type_big_key); +} + +static void __exit big_key_cleanup(void) +{ + unregister_key_type(&key_type_big_key); +} + +module_init(big_key_init); +module_exit(big_key_cleanup); -- cgit v1.2.3-70-g09d2 From f36f8c75ae2e7d4da34f4c908cebdb4aa42c977e Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:19 +0100 Subject: KEYS: Add per-user_namespace registers for persistent per-UID kerberos caches Add support for per-user_namespace registers of persistent per-UID kerberos caches held within the kernel. This allows the kerberos cache to be retained beyond the life of all a user's processes so that the user's cron jobs can work. The kerberos cache is envisioned as a keyring/key tree looking something like: struct user_namespace \___ .krb_cache keyring - The register \___ _krb.0 keyring - Root's Kerberos cache \___ _krb.5000 keyring - User 5000's Kerberos cache \___ _krb.5001 keyring - User 5001's Kerberos cache \___ tkt785 big_key - A ccache blob \___ tkt12345 big_key - Another ccache blob Or possibly: struct user_namespace \___ .krb_cache keyring - The register \___ _krb.0 keyring - Root's Kerberos cache \___ _krb.5000 keyring - User 5000's Kerberos cache \___ _krb.5001 keyring - User 5001's Kerberos cache \___ tkt785 keyring - A ccache \___ krbtgt/REDHAT.COM@REDHAT.COM big_key \___ http/REDHAT.COM@REDHAT.COM user \___ afs/REDHAT.COM@REDHAT.COM user \___ nfs/REDHAT.COM@REDHAT.COM user \___ krbtgt/KERNEL.ORG@KERNEL.ORG big_key \___ http/KERNEL.ORG@KERNEL.ORG big_key What goes into a particular Kerberos cache is entirely up to userspace. Kernel support is limited to giving you the Kerberos cache keyring that you want. The user asks for their Kerberos cache by: krb_cache = keyctl_get_krbcache(uid, dest_keyring); The uid is -1 or the user's own UID for the user's own cache or the uid of some other user's cache (requires CAP_SETUID). This permits rpc.gssd or whatever to mess with the cache. The cache returned is a keyring named "_krb." that the possessor can read, search, clear, invalidate, unlink from and add links to. Active LSMs get a chance to rule on whether the caller is permitted to make a link. Each uid's cache keyring is created when it first accessed and is given a timeout that is extended each time this function is called so that the keyring goes away after a while. The timeout is configurable by sysctl but defaults to three days. Each user_namespace struct gets a lazily-created keyring that serves as the register. The cache keyrings are added to it. This means that standard key search and garbage collection facilities are available. The user_namespace struct's register goes away when it does and anything left in it is then automatically gc'd. Signed-off-by: David Howells Tested-by: Simo Sorce cc: Serge E. Hallyn cc: Eric W. Biederman --- include/linux/user_namespace.h | 6 ++ include/uapi/linux/keyctl.h | 1 + kernel/user.c | 4 + kernel/user_namespace.c | 6 ++ security/keys/Kconfig | 17 +++++ security/keys/Makefile | 1 + security/keys/compat.c | 3 + security/keys/internal.h | 9 +++ security/keys/keyctl.c | 3 + security/keys/persistent.c | 169 +++++++++++++++++++++++++++++++++++++++++ security/keys/sysctl.c | 11 +++ 11 files changed, 230 insertions(+) create mode 100644 security/keys/persistent.c (limited to 'security/keys') diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index 4db29859464..4836ba3c1cd 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -27,6 +27,12 @@ struct user_namespace { kuid_t owner; kgid_t group; unsigned int proc_inum; + + /* Register of per-UID persistent keyrings for this namespace */ +#ifdef CONFIG_PERSISTENT_KEYRINGS + struct key *persistent_keyring_register; + struct rw_semaphore persistent_keyring_register_sem; +#endif }; extern struct user_namespace init_user_ns; diff --git a/include/uapi/linux/keyctl.h b/include/uapi/linux/keyctl.h index c9b7f4faf97..840cb990abe 100644 --- a/include/uapi/linux/keyctl.h +++ b/include/uapi/linux/keyctl.h @@ -56,5 +56,6 @@ #define KEYCTL_REJECT 19 /* reject a partially constructed key */ #define KEYCTL_INSTANTIATE_IOV 20 /* instantiate a partially constructed key */ #define KEYCTL_INVALIDATE 21 /* invalidate a key */ +#define KEYCTL_GET_PERSISTENT 22 /* get a user's persistent keyring */ #endif /* _LINUX_KEYCTL_H */ diff --git a/kernel/user.c b/kernel/user.c index 5bbb91988e6..a3a0dbfda32 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -51,6 +51,10 @@ struct user_namespace init_user_ns = { .owner = GLOBAL_ROOT_UID, .group = GLOBAL_ROOT_GID, .proc_inum = PROC_USER_INIT_INO, +#ifdef CONFIG_KEYS_KERBEROS_CACHE + .krb_cache_register_sem = + __RWSEM_INITIALIZER(init_user_ns.krb_cache_register_sem), +#endif }; EXPORT_SYMBOL_GPL(init_user_ns); diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 13fb1134ba5..240fb62cf39 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -101,6 +101,9 @@ int create_user_ns(struct cred *new) set_cred_user_ns(new, ns); +#ifdef CONFIG_PERSISTENT_KEYRINGS + init_rwsem(&ns->persistent_keyring_register_sem); +#endif return 0; } @@ -130,6 +133,9 @@ void free_user_ns(struct user_namespace *ns) do { parent = ns->parent; +#ifdef CONFIG_PERSISTENT_KEYRINGS + key_put(ns->persistent_keyring_register); +#endif proc_free_inum(ns->proc_inum); kmem_cache_free(user_ns_cachep, ns); ns = parent; diff --git a/security/keys/Kconfig b/security/keys/Kconfig index b56362275ec..53d8748c956 100644 --- a/security/keys/Kconfig +++ b/security/keys/Kconfig @@ -20,6 +20,23 @@ config KEYS If you are unsure as to whether this is required, answer N. +config PERSISTENT_KEYRINGS + bool "Enable register of persistent per-UID keyrings" + depends on KEYS + help + This option provides a register of persistent per-UID keyrings, + primarily aimed at Kerberos key storage. The keyrings are persistent + in the sense that they stay around after all processes of that UID + have exited, not that they survive the machine being rebooted. + + A particular keyring may be accessed by either the user whose keyring + it is or by a process with administrative privileges. The active + LSMs gets to rule on which admin-level processes get to access the + cache. + + Keyrings are created and added into the register upon demand and get + removed if they expire (a default timeout is set upon creation). + config BIG_KEYS tristate "Large payload keys" depends on KEYS diff --git a/security/keys/Makefile b/security/keys/Makefile index c487c77a00b..dfb3a7beded 100644 --- a/security/keys/Makefile +++ b/security/keys/Makefile @@ -18,6 +18,7 @@ obj-y := \ obj-$(CONFIG_KEYS_COMPAT) += compat.o obj-$(CONFIG_PROC_FS) += proc.o obj-$(CONFIG_SYSCTL) += sysctl.o +obj-$(CONFIG_PERSISTENT_KEYRINGS) += persistent.o # # Key types diff --git a/security/keys/compat.c b/security/keys/compat.c index d65fa7fa29b..bbd32c729db 100644 --- a/security/keys/compat.c +++ b/security/keys/compat.c @@ -138,6 +138,9 @@ asmlinkage long compat_sys_keyctl(u32 option, case KEYCTL_INVALIDATE: return keyctl_invalidate_key(arg2); + case KEYCTL_GET_PERSISTENT: + return keyctl_get_persistent(arg2, arg3); + default: return -EOPNOTSUPP; } diff --git a/security/keys/internal.h b/security/keys/internal.h index 581c6f68835..80b2aac4f50 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -255,6 +255,15 @@ extern long keyctl_invalidate_key(key_serial_t); extern long keyctl_instantiate_key_common(key_serial_t, const struct iovec *, unsigned, size_t, key_serial_t); +#ifdef CONFIG_PERSISTENT_KEYRINGS +extern long keyctl_get_persistent(uid_t, key_serial_t); +extern unsigned persistent_keyring_expiry; +#else +static inline long keyctl_get_persistent(uid_t uid, key_serial_t destring) +{ + return -EOPNOTSUPP; +} +#endif /* * Debugging key validation diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index 33cfd27b4de..cee72ce6422 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -1667,6 +1667,9 @@ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, case KEYCTL_INVALIDATE: return keyctl_invalidate_key((key_serial_t) arg2); + case KEYCTL_GET_PERSISTENT: + return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3); + default: return -EOPNOTSUPP; } diff --git a/security/keys/persistent.c b/security/keys/persistent.c new file mode 100644 index 00000000000..82f4957a7ac --- /dev/null +++ b/security/keys/persistent.c @@ -0,0 +1,169 @@ +/* General persistent per-UID keyrings register + * + * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include "internal.h" + +unsigned persistent_keyring_expiry = 3 * 24 * 3600; /* Expire after 3 days of non-use */ + +/* + * Create the persistent keyring register for the current user namespace. + * + * Called with the namespace's sem locked for writing. + */ +static int key_create_persistent_register(struct user_namespace *ns) +{ + struct key *reg = keyring_alloc(".persistent_register", + KUIDT_INIT(0), KGIDT_INIT(0), + current_cred(), + ((KEY_POS_ALL & ~KEY_POS_SETATTR) | + KEY_USR_VIEW | KEY_USR_READ), + KEY_ALLOC_NOT_IN_QUOTA, NULL); + if (IS_ERR(reg)) + return PTR_ERR(reg); + + ns->persistent_keyring_register = reg; + return 0; +} + +/* + * Create the persistent keyring for the specified user. + * + * Called with the namespace's sem locked for writing. + */ +static key_ref_t key_create_persistent(struct user_namespace *ns, kuid_t uid, + struct keyring_index_key *index_key) +{ + struct key *persistent; + key_ref_t reg_ref, persistent_ref; + + if (!ns->persistent_keyring_register) { + long err = key_create_persistent_register(ns); + if (err < 0) + return ERR_PTR(err); + } else { + reg_ref = make_key_ref(ns->persistent_keyring_register, true); + persistent_ref = find_key_to_update(reg_ref, index_key); + if (persistent_ref) + return persistent_ref; + } + + persistent = keyring_alloc(index_key->description, + uid, INVALID_GID, current_cred(), + ((KEY_POS_ALL & ~KEY_POS_SETATTR) | + KEY_USR_VIEW | KEY_USR_READ), + KEY_ALLOC_NOT_IN_QUOTA, + ns->persistent_keyring_register); + if (IS_ERR(persistent)) + return ERR_CAST(persistent); + + return make_key_ref(persistent, true); +} + +/* + * Get the persistent keyring for a specific UID and link it to the nominated + * keyring. + */ +static long key_get_persistent(struct user_namespace *ns, kuid_t uid, + key_ref_t dest_ref) +{ + struct keyring_index_key index_key; + struct key *persistent; + key_ref_t reg_ref, persistent_ref; + char buf[32]; + long ret; + + /* Look in the register if it exists */ + index_key.type = &key_type_keyring; + index_key.description = buf; + index_key.desc_len = sprintf(buf, "_persistent.%u", from_kuid(ns, uid)); + + if (ns->persistent_keyring_register) { + reg_ref = make_key_ref(ns->persistent_keyring_register, true); + down_read(&ns->persistent_keyring_register_sem); + persistent_ref = find_key_to_update(reg_ref, &index_key); + up_read(&ns->persistent_keyring_register_sem); + + if (persistent_ref) + goto found; + } + + /* It wasn't in the register, so we'll need to create it. We might + * also need to create the register. + */ + down_write(&ns->persistent_keyring_register_sem); + persistent_ref = key_create_persistent(ns, uid, &index_key); + up_write(&ns->persistent_keyring_register_sem); + if (!IS_ERR(persistent_ref)) + goto found; + + return PTR_ERR(persistent_ref); + +found: + ret = key_task_permission(persistent_ref, current_cred(), KEY_LINK); + if (ret == 0) { + persistent = key_ref_to_ptr(persistent_ref); + ret = key_link(key_ref_to_ptr(dest_ref), persistent); + if (ret == 0) { + key_set_timeout(persistent, persistent_keyring_expiry); + ret = persistent->serial; + } + } + + key_ref_put(persistent_ref); + return ret; +} + +/* + * Get the persistent keyring for a specific UID and link it to the nominated + * keyring. + */ +long keyctl_get_persistent(uid_t _uid, key_serial_t destid) +{ + struct user_namespace *ns = current_user_ns(); + key_ref_t dest_ref; + kuid_t uid; + long ret; + + /* -1 indicates the current user */ + if (_uid == (uid_t)-1) { + uid = current_uid(); + } else { + uid = make_kuid(ns, _uid); + if (!uid_valid(uid)) + return -EINVAL; + + /* You can only see your own persistent cache if you're not + * sufficiently privileged. + */ + if (uid_eq(uid, current_uid()) && + uid_eq(uid, current_suid()) && + uid_eq(uid, current_euid()) && + uid_eq(uid, current_fsuid()) && + !ns_capable(ns, CAP_SETUID)) + return -EPERM; + } + + /* There must be a destination keyring */ + dest_ref = lookup_user_key(destid, KEY_LOOKUP_CREATE, KEY_WRITE); + if (IS_ERR(dest_ref)) + return PTR_ERR(dest_ref); + if (key_ref_to_ptr(dest_ref)->type != &key_type_keyring) { + ret = -ENOTDIR; + goto out_put_dest; + } + + ret = key_get_persistent(ns, uid, dest_ref); + +out_put_dest: + key_ref_put(dest_ref); + return ret; +} diff --git a/security/keys/sysctl.c b/security/keys/sysctl.c index ee32d181764..8c0af08760c 100644 --- a/security/keys/sysctl.c +++ b/security/keys/sysctl.c @@ -61,5 +61,16 @@ ctl_table key_sysctls[] = { .extra1 = (void *) &zero, .extra2 = (void *) &max, }, +#ifdef CONFIG_PERSISTENT_KEYRINGS + { + .procname = "persistent_keyring_expiry", + .data = &persistent_keyring_expiry, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) &zero, + .extra2 = (void *) &max, + }, +#endif { } }; -- cgit v1.2.3-70-g09d2 From 008643b86c5f33c115c84ccdda1725cac3ad50ad Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 30 Aug 2013 16:07:37 +0100 Subject: KEYS: Add a 'trusted' flag and a 'trusted only' flag Add KEY_FLAG_TRUSTED to indicate that a key either comes from a trusted source or had a cryptographic signature chain that led back to a trusted key the kernel already possessed. Add KEY_FLAGS_TRUSTED_ONLY to indicate that a keyring will only accept links to keys marked with KEY_FLAGS_TRUSTED. Signed-off-by: David Howells Reviewed-by: Kees Cook --- include/linux/key-type.h | 1 + include/linux/key.h | 3 +++ kernel/system_keyring.c | 4 +++- security/keys/key.c | 8 ++++++++ security/keys/keyring.c | 4 ++++ 5 files changed, 19 insertions(+), 1 deletion(-) (limited to 'security/keys') diff --git a/include/linux/key-type.h b/include/linux/key-type.h index f58737bcb05..a74c3a84dfd 100644 --- a/include/linux/key-type.h +++ b/include/linux/key-type.h @@ -45,6 +45,7 @@ struct key_preparsed_payload { const void *data; /* Raw data */ size_t datalen; /* Raw datalen */ size_t quotalen; /* Quota length for proposed payload */ + bool trusted; /* True if key is trusted */ }; typedef int (*request_key_actor_t)(struct key_construction *key, diff --git a/include/linux/key.h b/include/linux/key.h index 010dbb618ac..80d677483e3 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -168,6 +168,8 @@ struct key { #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */ #define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */ #define KEY_FLAG_INVALIDATED 7 /* set if key has been invalidated */ +#define KEY_FLAG_TRUSTED 8 /* set if key is trusted */ +#define KEY_FLAG_TRUSTED_ONLY 9 /* set if keyring only accepts links to trusted keys */ /* the key type and key description string * - the desc is used to match a key against search criteria @@ -218,6 +220,7 @@ extern struct key *key_alloc(struct key_type *type, #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ +#define KEY_ALLOC_TRUSTED 0x0004 /* Key should be flagged as trusted */ extern void key_revoke(struct key *key); extern void key_invalidate(struct key *key); diff --git a/kernel/system_keyring.c b/kernel/system_keyring.c index 51c35141a13..5296721eca5 100644 --- a/kernel/system_keyring.c +++ b/kernel/system_keyring.c @@ -40,6 +40,7 @@ static __init int system_trusted_keyring_init(void) if (IS_ERR(system_trusted_keyring)) panic("Can't allocate system trusted keyring\n"); + set_bit(KEY_FLAG_TRUSTED_ONLY, &system_trusted_keyring->flags); return 0; } @@ -82,7 +83,8 @@ static __init int load_system_certificate_list(void) plen, (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW, - KEY_ALLOC_NOT_IN_QUOTA); + KEY_ALLOC_NOT_IN_QUOTA | + KEY_ALLOC_TRUSTED); if (IS_ERR(key)) { pr_err("Problem loading in-kernel X.509 certificate (%ld)\n", PTR_ERR(key)); diff --git a/security/keys/key.c b/security/keys/key.c index a819b5c7d4e..d331ea9ef38 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -300,6 +300,8 @@ struct key *key_alloc(struct key_type *type, const char *desc, if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) key->flags |= 1 << KEY_FLAG_IN_QUOTA; + if (flags & KEY_ALLOC_TRUSTED) + key->flags |= 1 << KEY_FLAG_TRUSTED; memset(&key->type_data, 0, sizeof(key->type_data)); @@ -813,6 +815,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, prep.data = payload; prep.datalen = plen; prep.quotalen = index_key.type->def_datalen; + prep.trusted = flags & KEY_ALLOC_TRUSTED; if (index_key.type->preparse) { ret = index_key.type->preparse(&prep); if (ret < 0) { @@ -827,6 +830,11 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, } index_key.desc_len = strlen(index_key.description); + key_ref = ERR_PTR(-EPERM); + if (!prep.trusted && test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags)) + goto error_free_prep; + flags |= prep.trusted ? KEY_ALLOC_TRUSTED : 0; + ret = __key_link_begin(keyring, &index_key, &edit); if (ret < 0) { key_ref = ERR_PTR(ret); diff --git a/security/keys/keyring.c b/security/keys/keyring.c index f7cdea22214..9b6f6e09b50 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -1183,6 +1183,10 @@ int key_link(struct key *keyring, struct key *key) key_check(keyring); key_check(key); + if (test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags) && + !test_bit(KEY_FLAG_TRUSTED, &key->flags)) + return -EPERM; + ret = __key_link_begin(keyring, &key->index_key, &edit); if (ret == 0) { kdebug("begun {%d,%d}", keyring->serial, atomic_read(&keyring->usage)); -- cgit v1.2.3-70-g09d2 From c124bde28bce41f9e46e32d03d134a81e116d38c Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Wed, 4 Sep 2013 13:26:22 +0100 Subject: KEYS: initialize root uid and session keyrings early In order to create the integrity keyrings (eg. _evm, _ima), root's uid and session keyrings need to be initialized early. Signed-off-by: Mimi Zohar Signed-off-by: David Howells --- security/keys/process_keys.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'security/keys') diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c index 68548ea6fe0..0cf8a130a26 100644 --- a/security/keys/process_keys.c +++ b/security/keys/process_keys.c @@ -857,3 +857,13 @@ void key_change_session_keyring(struct callback_head *twork) commit_creds(new); } + +/* + * Make sure that root's user and user-session keyrings exist. + */ +static int __init init_root_keyring(void) +{ + return install_user_keyrings(); +} + +late_initcall(init_root_keyring); -- cgit v1.2.3-70-g09d2 From 2eaf6b5dcafda2b8c22930eff7f48a364fce1741 Mon Sep 17 00:00:00 2001 From: Josh Boyer Date: Wed, 30 Oct 2013 11:15:23 +0000 Subject: KEYS: Make BIG_KEYS boolean Having the big_keys functionality as a module is very marginally useful. The userspace code that would use this functionality will get odd error messages from the keys layer if the module isn't loaded. The code itself is fairly small, so just have this as a boolean option and not a tristate. Signed-off-by: Josh Boyer Signed-off-by: David Howells --- security/keys/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'security/keys') diff --git a/security/keys/Kconfig b/security/keys/Kconfig index 53d8748c956..a4f3f8c48d6 100644 --- a/security/keys/Kconfig +++ b/security/keys/Kconfig @@ -38,7 +38,7 @@ config PERSISTENT_KEYRINGS removed if they expire (a default timeout is set upon creation). config BIG_KEYS - tristate "Large payload keys" + bool "Large payload keys" depends on KEYS depends on TMPFS help -- cgit v1.2.3-70-g09d2 From 74792b0001ee85b845dc82c1a716c6052c2db9de Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 30 Oct 2013 11:15:24 +0000 Subject: KEYS: Fix a race between negating a key and reading the error set key_reject_and_link() marking a key as negative and setting the error with which it was negated races with keyring searches and other things that read that error. The fix is to switch the order in which the assignments are done in key_reject_and_link() and to use memory barriers. Kudos to Dave Wysochanski and Scott Mayhew for tracking this down. This may be the cause of: BUG: unable to handle kernel NULL pointer dereference at 0000000000000070 IP: [] wait_for_key_construction+0x31/0x80 PGD c6b2c3067 PUD c59879067 PMD 0 Oops: 0000 [#1] SMP last sysfs file: /sys/devices/system/cpu/cpu3/cache/index2/shared_cpu_map CPU 0 Modules linked in: ... Pid: 13359, comm: amqzxma0 Not tainted 2.6.32-358.20.1.el6.x86_64 #1 IBM System x3650 M3 -[7945PSJ]-/00J6159 RIP: 0010:[] wait_for_key_construction+0x31/0x80 RSP: 0018:ffff880c6ab33758 EFLAGS: 00010246 RAX: ffffffff81219080 RBX: 0000000000000000 RCX: 0000000000000002 RDX: ffffffff81219060 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff880c6ab33768 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff880adfcbce40 R13: ffffffffa03afb84 R14: ffff880adfcbce40 R15: ffff880adfcbce43 FS: 00007f29b8042700(0000) GS:ffff880028200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000070 CR3: 0000000c613dc000 CR4: 00000000000007f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process amqzxma0 (pid: 13359, threadinfo ffff880c6ab32000, task ffff880c610deae0) Stack: ffff880adfcbce40 0000000000000000 ffff880c6ab337b8 ffffffff81219695 0000000000000000 ffff880a000000d0 ffff880c6ab337a8 000000000000000f ffffffffa03afb93 000000000000000f ffff88186c7882c0 0000000000000014 Call Trace: [] request_key+0x65/0xa0 [] nfs_idmap_request_key+0xc5/0x170 [nfs] [] nfs_idmap_lookup_id+0x34/0x80 [nfs] [] nfs_map_group_to_gid+0x75/0xa0 [nfs] [] decode_getfattr_attrs+0xbdd/0xfb0 [nfs] [] ? __dequeue_entity+0x30/0x50 [] ? __switch_to+0x26e/0x320 [] decode_getfattr+0x83/0xe0 [nfs] [] ? nfs4_xdr_dec_getattr+0x0/0xa0 [nfs] [] nfs4_xdr_dec_getattr+0x8f/0xa0 [nfs] [] rpcauth_unwrap_resp+0x84/0xb0 [sunrpc] [] ? nfs4_xdr_dec_getattr+0x0/0xa0 [nfs] [] call_decode+0x1b3/0x800 [sunrpc] [] ? wake_bit_function+0x0/0x50 [] ? call_decode+0x0/0x800 [sunrpc] [] __rpc_execute+0x77/0x350 [sunrpc] [] ? bit_waitqueue+0x17/0xd0 [] rpc_execute+0x61/0xa0 [sunrpc] [] rpc_run_task+0x75/0x90 [sunrpc] [] rpc_call_sync+0x42/0x70 [sunrpc] [] _nfs4_call_sync+0x30/0x40 [nfs] [] _nfs4_proc_getattr+0xac/0xc0 [nfs] [] ? futex_wait+0x227/0x380 [] nfs4_proc_getattr+0x56/0x80 [nfs] [] __nfs_revalidate_inode+0xe3/0x220 [nfs] [] nfs_revalidate_mapping+0x4e/0x170 [nfs] [] nfs_file_read+0x77/0x130 [nfs] [] do_sync_read+0xfa/0x140 [] ? autoremove_wake_function+0x0/0x40 [] ? apic_timer_interrupt+0xe/0x20 [] ? common_interrupt+0xe/0x13 [] ? selinux_file_permission+0xfb/0x150 [] ? security_file_permission+0x16/0x20 [] vfs_read+0xb5/0x1a0 [] sys_read+0x51/0x90 [] ? __audit_syscall_exit+0x265/0x290 [] system_call_fastpath+0x16/0x1b Signed-off-by: David Howells cc: Dave Wysochanski cc: Scott Mayhew --- security/keys/key.c | 3 ++- security/keys/keyring.c | 1 + security/keys/request_key.c | 4 +++- 3 files changed, 6 insertions(+), 2 deletions(-) (limited to 'security/keys') diff --git a/security/keys/key.c b/security/keys/key.c index d331ea9ef38..55d110f0ace 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -557,9 +557,10 @@ int key_reject_and_link(struct key *key, if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { /* mark the key as being negatively instantiated */ atomic_inc(&key->user->nikeys); + key->type_data.reject_error = -error; + smp_wmb(); set_bit(KEY_FLAG_NEGATIVE, &key->flags); set_bit(KEY_FLAG_INSTANTIATED, &key->flags); - key->type_data.reject_error = -error; now = current_kernel_time(); key->expiry = now.tv_sec + timeout; key_schedule_gc(key->expiry + key_gc_delay); diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 9b6f6e09b50..8c05ebd7203 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -551,6 +551,7 @@ static int keyring_search_iterator(const void *object, void *iterator_data) if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { /* we set a different error code if we pass a negative key */ if (kflags & (1 << KEY_FLAG_NEGATIVE)) { + smp_rmb(); ctx->result = ERR_PTR(key->type_data.reject_error); kleave(" = %d [neg]", ctx->skipped_ret); goto skipped; diff --git a/security/keys/request_key.c b/security/keys/request_key.c index df94827103d..381411941cc 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -596,8 +596,10 @@ int wait_for_key_construction(struct key *key, bool intr) intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE); if (ret < 0) return ret; - if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) + if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) { + smp_rmb(); return key->type_data.reject_error; + } return key_validate(key); } EXPORT_SYMBOL(wait_for_key_construction); -- cgit v1.2.3-70-g09d2 From 034faeb9ef390d58239e1dce748143f6b35a0d9b Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 30 Oct 2013 11:15:24 +0000 Subject: KEYS: Fix keyring quota misaccounting on key replacement and unlink If a key is displaced from a keyring by a matching one, then four more bytes of quota are allocated to the keyring - despite the fact that the keyring does not change in size. Further, when a key is unlinked from a keyring, the four bytes of quota allocated the link isn't recovered and returned to the user's pool. The first can be tested by repeating: keyctl add big_key a fred @s cat /proc/key-users (Don't put it in a shell loop otherwise the garbage collector won't have time to clear the displaced keys, thus affecting the result). This was causing the kerberos keyring to run out of room fairly quickly. The second can be tested by: cat /proc/key-users a=`keyctl add user a a @s` cat /proc/key-users keyctl unlink $a sleep 1 # Give RCU a chance to delete the key cat /proc/key-users assuming no system activity that otherwise adds/removes keys, the amount of key data allocated should go up (say 40/20000 -> 47/20000) and then return to the original value at the end. Reported-by: Stephen Gallagher Signed-off-by: David Howells --- security/keys/keyring.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) (limited to 'security/keys') diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 8c05ebd7203..d80311e571c 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -1063,12 +1063,6 @@ int __key_link_begin(struct key *keyring, if (index_key->type == &key_type_keyring) down_write(&keyring_serialise_link_sem); - /* check that we aren't going to overrun the user's quota */ - ret = key_payload_reserve(keyring, - keyring->datalen + KEYQUOTA_LINK_BYTES); - if (ret < 0) - goto error_sem; - /* Create an edit script that will insert/replace the key in the * keyring tree. */ @@ -1078,17 +1072,25 @@ int __key_link_begin(struct key *keyring, NULL); if (IS_ERR(edit)) { ret = PTR_ERR(edit); - goto error_quota; + goto error_sem; + } + + /* If we're not replacing a link in-place then we're going to need some + * extra quota. + */ + if (!edit->dead_leaf) { + ret = key_payload_reserve(keyring, + keyring->datalen + KEYQUOTA_LINK_BYTES); + if (ret < 0) + goto error_cancel; } *_edit = edit; kleave(" = 0"); return 0; -error_quota: - /* undo the quota changes */ - key_payload_reserve(keyring, - keyring->datalen - KEYQUOTA_LINK_BYTES); +error_cancel: + assoc_array_cancel_edit(edit); error_sem: if (index_key->type == &key_type_keyring) up_write(&keyring_serialise_link_sem); @@ -1146,7 +1148,7 @@ void __key_link_end(struct key *keyring, if (index_key->type == &key_type_keyring) up_write(&keyring_serialise_link_sem); - if (edit) { + if (edit && !edit->dead_leaf) { key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES); assoc_array_cancel_edit(edit); @@ -1243,6 +1245,7 @@ int key_unlink(struct key *keyring, struct key *key) goto error; assoc_array_apply_edit(edit); + key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES); ret = 0; error: -- cgit v1.2.3-70-g09d2 From d2b86970245b64652c4d7799e707dd8bd1533b64 Mon Sep 17 00:00:00 2001 From: Wei Yongjun Date: Wed, 30 Oct 2013 11:23:02 +0800 Subject: KEYS: fix error return code in big_key_instantiate() Fix to return a negative error code from the error handling case instead of 0, as done elsewhere in this function. Signed-off-by: Wei Yongjun Signed-off-by: David Howells --- security/keys/big_key.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'security/keys') diff --git a/security/keys/big_key.c b/security/keys/big_key.c index 5f9defc4a80..2cf5e62d67a 100644 --- a/security/keys/big_key.c +++ b/security/keys/big_key.c @@ -71,8 +71,10 @@ int big_key_instantiate(struct key *key, struct key_preparsed_payload *prep) * TODO: Encrypt the stored data with a temporary key. */ file = shmem_file_setup("", datalen, 0); - if (IS_ERR(file)) + if (IS_ERR(file)) { + ret = PTR_ERR(file); goto err_quota; + } written = kernel_write(file, prep->data, prep->datalen, 0); if (written != datalen) { -- cgit v1.2.3-70-g09d2 From fbf8c53f1a2ac7610ed124043600dc074992e71b Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 6 Nov 2013 14:01:51 +0000 Subject: KEYS: Fix UID check in keyctl_get_persistent() If the UID is specified by userspace when calling the KEYCTL_GET_PERSISTENT function and the process does not have the CAP_SETUID capability, then the function will return -EPERM if the current process's uid, suid, euid and fsuid all match the requested UID. This is incorrect. Fix it such that when a non-privileged caller requests a persistent keyring by a specific UID they can only request their own (ie. the specified UID matches either then process's UID or the process's EUID). This can be tested by logging in as the user and doing: keyctl get_persistent @p keyctl get_persistent @p `id -u` keyctl get_persistent @p 0 The first two should successfully print the same key ID. The third should do the same if called by UID 0 or indicate Operation Not Permitted otherwise. Signed-off-by: David Howells Acked-by: Stephen Gallagher --- security/keys/persistent.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'security/keys') diff --git a/security/keys/persistent.c b/security/keys/persistent.c index 82f4957a7ac..0ad3ee28378 100644 --- a/security/keys/persistent.c +++ b/security/keys/persistent.c @@ -144,10 +144,8 @@ long keyctl_get_persistent(uid_t _uid, key_serial_t destid) /* You can only see your own persistent cache if you're not * sufficiently privileged. */ - if (uid_eq(uid, current_uid()) && - uid_eq(uid, current_suid()) && - uid_eq(uid, current_euid()) && - uid_eq(uid, current_fsuid()) && + if (!uid_eq(uid, current_uid()) && + !uid_eq(uid, current_euid()) && !ns_capable(ns, CAP_SETUID)) return -EPERM; } -- cgit v1.2.3-70-g09d2 From 97826c821ec6724fc359d9b7840dc10af914c641 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 13 Nov 2013 16:51:06 +0000 Subject: KEYS: Fix error handling in big_key instantiation In the big_key_instantiate() function we return 0 if kernel_write() returns us an error rather than returning an error. This can potentially lead to dentry_open() giving a BUG when called from big_key_read() with an unset tmpfile path. ------------[ cut here ]------------ kernel BUG at fs/open.c:798! ... RIP: 0010:[] dentry_open+0xd1/0xe0 ... Call Trace: [] big_key_read+0x55/0x100 [] keyctl_read_key+0xb4/0xe0 [] SyS_keyctl+0xf8/0x1d0 [] system_call_fastpath+0x16/0x1b Signed-off-by: David Howells Reviewed-by: Stephen Gallagher --- security/keys/big_key.c | 1 + 1 file changed, 1 insertion(+) (limited to 'security/keys') diff --git a/security/keys/big_key.c b/security/keys/big_key.c index 2cf5e62d67a..7f44c3207a9 100644 --- a/security/keys/big_key.c +++ b/security/keys/big_key.c @@ -78,6 +78,7 @@ int big_key_instantiate(struct key *key, struct key_preparsed_payload *prep) written = kernel_write(file, prep->data, prep->datalen, 0); if (written != datalen) { + ret = written; if (written >= 0) ret = -ENOMEM; goto err_fput; -- cgit v1.2.3-70-g09d2 From 62fe318256befbd1b4a6765e71d9c997f768fe79 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 14 Nov 2013 13:02:31 +0000 Subject: KEYS: Fix keyring content gc scanner Key pointers stored in the keyring are marked in bit 1 to indicate if they point to a keyring. We need to strip off this bit before using the pointer when iterating over the keyring for the purpose of looking for links to garbage collect. This means that expirable keyrings aren't correctly expiring because the checker is seeing their key pointer with 2 added to it. Since the fix for this involves knowing about the internals of the keyring, key_gc_keyring() is moved to keyring.c and merged into keyring_gc(). This can be tested by: echo 2 >/proc/sys/kernel/keys/gc_delay keyctl timeout `keyctl add keyring qwerty "" @s` 2 cat /proc/keys sleep 5; cat /proc/keys which should see a keyring called "qwerty" appear in the session keyring and then disappear after it expires, and: echo 2 >/proc/sys/kernel/keys/gc_delay a=`keyctl get_persistent @s` b=`keyctl add keyring 0 "" $a` keyctl add user a a $b keyctl timeout $b 2 cat /proc/keys sleep 5; cat /proc/keys which should see a keyring called "0" with a key called "a" in it appear in the user's persistent keyring (which will be attached to the session keyring) and then both the "0" keyring and the "a" key should disappear when the "0" keyring expires. Signed-off-by: David Howells Acked-by: Simo Sorce --- security/keys/gc.c | 42 +----------------------------------------- security/keys/keyring.c | 45 +++++++++++++++++++++++++++++++++++---------- 2 files changed, 36 insertions(+), 51 deletions(-) (limited to 'security/keys') diff --git a/security/keys/gc.c b/security/keys/gc.c index cce621c33dc..d3222b6d7d5 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -130,46 +130,6 @@ void key_gc_keytype(struct key_type *ktype) kleave(""); } -static int key_gc_keyring_func(const void *object, void *iterator_data) -{ - const struct key *key = object; - time_t *limit = iterator_data; - return key_is_dead(key, *limit); -} - -/* - * Garbage collect pointers from a keyring. - * - * Not called with any locks held. The keyring's key struct will not be - * deallocated under us as only our caller may deallocate it. - */ -static void key_gc_keyring(struct key *keyring, time_t limit) -{ - int result; - - kenter("%x{%s}", keyring->serial, keyring->description ?: ""); - - if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | - (1 << KEY_FLAG_REVOKED))) - goto dont_gc; - - /* scan the keyring looking for dead keys */ - rcu_read_lock(); - result = assoc_array_iterate(&keyring->keys, - key_gc_keyring_func, &limit); - rcu_read_unlock(); - if (result == true) - goto do_gc; - -dont_gc: - kleave(" [no gc]"); - return; - -do_gc: - keyring_gc(keyring, limit); - kleave(" [gc]"); -} - /* * Garbage collect a list of unreferenced, detached keys */ @@ -388,7 +348,7 @@ found_unreferenced_key: */ found_keyring: spin_unlock(&key_serial_lock); - key_gc_keyring(key, limit); + keyring_gc(key, limit); goto maybe_resched; /* We found a dead key that is still referenced. Reset its type and diff --git a/security/keys/keyring.c b/security/keys/keyring.c index d80311e571c..69f0cb7bab7 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -1304,7 +1304,7 @@ static void keyring_revoke(struct key *keyring) } } -static bool gc_iterator(void *object, void *iterator_data) +static bool keyring_gc_select_iterator(void *object, void *iterator_data) { struct key *key = keyring_ptr_to_key(object); time_t *limit = iterator_data; @@ -1315,22 +1315,47 @@ static bool gc_iterator(void *object, void *iterator_data) return true; } +static int keyring_gc_check_iterator(const void *object, void *iterator_data) +{ + const struct key *key = keyring_ptr_to_key(object); + time_t *limit = iterator_data; + + key_check(key); + return key_is_dead(key, *limit); +} + /* - * Collect garbage from the contents of a keyring, replacing the old list with - * a new one with the pointers all shuffled down. + * Garbage collect pointers from a keyring. * - * Dead keys are classed as oned that are flagged as being dead or are revoked, - * expired or negative keys that were revoked or expired before the specified - * limit. + * Not called with any locks held. The keyring's key struct will not be + * deallocated under us as only our caller may deallocate it. */ void keyring_gc(struct key *keyring, time_t limit) { - kenter("{%x,%s}", key_serial(keyring), keyring->description); + int result; + + kenter("%x{%s}", keyring->serial, keyring->description ?: ""); + if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | + (1 << KEY_FLAG_REVOKED))) + goto dont_gc; + + /* scan the keyring looking for dead keys */ + rcu_read_lock(); + result = assoc_array_iterate(&keyring->keys, + keyring_gc_check_iterator, &limit); + rcu_read_unlock(); + if (result == true) + goto do_gc; + +dont_gc: + kleave(" [no gc]"); + return; + +do_gc: down_write(&keyring->sem); assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops, - gc_iterator, &limit); + keyring_gc_select_iterator, &limit); up_write(&keyring->sem); - - kleave(""); + kleave(" [gc]"); } -- cgit v1.2.3-70-g09d2 From 2480f57fb3023eb047c5f2d6dfefef41ab9b893c Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 2 Dec 2013 11:24:18 +0000 Subject: KEYS: Pre-clear struct key on allocation The second word of key->payload does not get initialised in key_alloc(), but the big_key type is relying on it having been cleared. The problem comes when big_key fails to instantiate a large key and doesn't then set the payload. The big_key_destroy() op is called from the garbage collector and this assumes that the dentry pointer stored in the second word will be NULL if instantiation did not complete. Therefore just pre-clear the entire struct key on allocation rather than trying to be clever and only initialising to 0 only those bits that aren't otherwise initialised. The lack of initialisation can lead to a bug report like the following if big_key failed to initialise its file: general protection fault: 0000 [#1] SMP Modules linked in: ... CPU: 0 PID: 51 Comm: kworker/0:1 Not tainted 3.10.0-53.el7.x86_64 #1 Hardware name: Dell Inc. PowerEdge 1955/0HC513, BIOS 1.4.4 12/09/2008 Workqueue: events key_garbage_collector task: ffff8801294f5680 ti: ffff8801296e2000 task.ti: ffff8801296e2000 RIP: 0010:[] dput+0x21/0x2d0 ... Call Trace: [] path_put+0x16/0x30 [] big_key_destroy+0x44/0x60 [] key_gc_unused_keys.constprop.2+0x5b/0xe0 [] key_garbage_collector+0x1df/0x3c0 [] process_one_work+0x17b/0x460 [] worker_thread+0x11b/0x400 [] ? rescuer_thread+0x3e0/0x3e0 [] kthread+0xc0/0xd0 [] ? kthread_create_on_node+0x110/0x110 [] ret_from_fork+0x7c/0xb0 [] ? kthread_create_on_node+0x110/0x110 Reported-by: Patrik Kis Signed-off-by: David Howells Reviewed-by: Stephen Gallagher --- security/keys/key.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) (limited to 'security/keys') diff --git a/security/keys/key.c b/security/keys/key.c index 55d110f0ace..6e21c11e48b 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -272,7 +272,7 @@ struct key *key_alloc(struct key_type *type, const char *desc, } /* allocate and initialise the key and its description */ - key = kmem_cache_alloc(key_jar, GFP_KERNEL); + key = kmem_cache_zalloc(key_jar, GFP_KERNEL); if (!key) goto no_memory_2; @@ -293,18 +293,12 @@ struct key *key_alloc(struct key_type *type, const char *desc, key->uid = uid; key->gid = gid; key->perm = perm; - key->flags = 0; - key->expiry = 0; - key->payload.data = NULL; - key->security = NULL; if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) key->flags |= 1 << KEY_FLAG_IN_QUOTA; if (flags & KEY_ALLOC_TRUSTED) key->flags |= 1 << KEY_FLAG_TRUSTED; - memset(&key->type_data, 0, sizeof(key->type_data)); - #ifdef KEY_DEBUGGING key->magic = KEY_DEBUG_MAGIC; #endif -- cgit v1.2.3-70-g09d2 From d54e58b7f01552b0eb7d445f4b58de4499ad5ea6 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 2 Dec 2013 11:24:18 +0000 Subject: KEYS: Fix the keyring hash function The keyring hash function (used by the associative array) is supposed to clear the bottommost nibble of the index key (where the hash value resides) for keyrings and make sure it is non-zero for non-keyrings. This is done to make keyrings cluster together on one branch of the tree separately to other keys. Unfortunately, the wrong mask is used, so only the bottom two bits are examined and cleared and not the whole bottom nibble. This means that keys and keyrings can still be successfully searched for under most circumstances as the hash is consistent in its miscalculation, but if a keyring's associative array bottom node gets filled up then approx 75% of the keyrings will not be put into the 0 branch. The consequence of this is that a key in a keyring linked to by another keyring, ie. keyring A -> keyring B -> key may not be found if the search starts at keyring A and then descends into keyring B because search_nested_keyrings() only searches up the 0 branch (as it "knows" all keyrings must be there and not elsewhere in the tree). The fix is to use the right mask. This can be tested with: r=`keyctl newring sandbox @s` for ((i=0; i<=16; i++)); do keyctl newring ring$i $r; done for ((i=0; i<=16; i++)); do keyctl add user a$i a %:ring$i; done for ((i=0; i<=16; i++)); do keyctl search $r user a$i; done This creates a sandbox keyring, then creates 17 keyrings therein (labelled ring0..ring16). This causes the root node of the sandbox's associative array to overflow and for the tree to have extra nodes inserted. Each keyring then is given a user key (labelled aN for ringN) for us to search for. We then search for the user keys we added, starting from the sandbox. If working correctly, it should return the same ordered list of key IDs as for...keyctl add... did. Without this patch, it reports ENOKEY "Required key not available" for some of the keys. Just which keys get this depends as the kernel pointer to the key type forms part of the hash function. Reported-by: Nalin Dahyabhai Signed-off-by: David Howells Tested-by: Stephen Gallagher --- security/keys/keyring.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'security/keys') diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 69f0cb7bab7..0adbc77a59b 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -160,7 +160,7 @@ static u64 mult_64x32_and_fold(u64 x, u32 y) static unsigned long hash_key_type_and_desc(const struct keyring_index_key *index_key) { const unsigned level_shift = ASSOC_ARRAY_LEVEL_STEP; - const unsigned long level_mask = ASSOC_ARRAY_LEVEL_STEP_MASK; + const unsigned long fan_mask = ASSOC_ARRAY_FAN_MASK; const char *description = index_key->description; unsigned long hash, type; u32 piece; @@ -194,10 +194,10 @@ static unsigned long hash_key_type_and_desc(const struct keyring_index_key *inde * ordinary keys by making sure the lowest level segment in the hash is * zero for keyrings and non-zero otherwise. */ - if (index_key->type != &key_type_keyring && (hash & level_mask) == 0) + if (index_key->type != &key_type_keyring && (hash & fan_mask) == 0) return hash | (hash >> (ASSOC_ARRAY_KEY_CHUNK_SIZE - level_shift)) | 1; - if (index_key->type == &key_type_keyring && (hash & level_mask) != 0) - return (hash + (hash << level_shift)) & ~level_mask; + if (index_key->type == &key_type_keyring && (hash & fan_mask) != 0) + return (hash + (hash << level_shift)) & ~fan_mask; return hash; } -- cgit v1.2.3-70-g09d2 From 23fd78d76415729b338ff1802a0066b4a62f7fb8 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 2 Dec 2013 11:24:18 +0000 Subject: KEYS: Fix multiple key add into associative array If sufficient keys (or keyrings) are added into a keyring such that a node in the associative array's tree overflows (each node has a capacity N, currently 16) and such that all N+1 keys have the same index key segment for that level of the tree (the level'th nibble of the index key), then assoc_array_insert() calls ops->diff_objects() to indicate at which bit position the two index keys vary. However, __key_link_begin() passes a NULL object to assoc_array_insert() with the intention of supplying the correct pointer later before we commit the change. This means that keyring_diff_objects() is given a NULL pointer as one of its arguments which it does not expect. This results in an oops like the attached. With the previous patch to fix the keyring hash function, this can be forced much more easily by creating a keyring and only adding keyrings to it. Add any other sort of key and a different insertion path is taken - all 16+1 objects must want to cluster in the same node slot. This can be tested by: r=`keyctl newring sandbox @s` for ((i=0; i<=16; i++)); do keyctl newring ring$i $r; done This should work fine, but oopses when the 17th keyring is added. Since ops->diff_objects() is always called with the first pointer pointing to the object to be inserted (ie. the NULL pointer), we can fix the problem by changing the to-be-inserted object pointer to point to the index key passed into assoc_array_insert() instead. Whilst we're at it, we also switch the arguments so that they are the same as for ->compare_object(). BUG: unable to handle kernel NULL pointer dereference at 0000000000000088 IP: [] hash_key_type_and_desc+0x18/0xb0 ... RIP: 0010:[] hash_key_type_and_desc+0x18/0xb0 ... Call Trace: [] keyring_diff_objects+0x21/0xd2 [] assoc_array_insert+0x3b6/0x908 [] __key_link_begin+0x78/0xe5 [] key_create_or_update+0x17d/0x36a [] SyS_add_key+0x123/0x183 [] tracesys+0xdd/0xe2 Signed-off-by: David Howells Tested-by: Stephen Gallagher --- Documentation/assoc_array.txt | 6 +++--- include/linux/assoc_array.h | 6 +++--- lib/assoc_array.c | 4 ++-- security/keys/keyring.c | 7 +++---- 4 files changed, 11 insertions(+), 12 deletions(-) (limited to 'security/keys') diff --git a/Documentation/assoc_array.txt b/Documentation/assoc_array.txt index f4faec0f66e..2f2c6cdd73c 100644 --- a/Documentation/assoc_array.txt +++ b/Documentation/assoc_array.txt @@ -164,10 +164,10 @@ This points to a number of methods, all of which need to be provided: (4) Diff the index keys of two objects. - int (*diff_objects)(const void *a, const void *b); + int (*diff_objects)(const void *object, const void *index_key); - Return the bit position at which the index keys of two objects differ or - -1 if they are the same. + Return the bit position at which the index key of the specified object + differs from the given index key or -1 if they are the same. (5) Free an object. diff --git a/include/linux/assoc_array.h b/include/linux/assoc_array.h index 9a193b84238..a89df3be168 100644 --- a/include/linux/assoc_array.h +++ b/include/linux/assoc_array.h @@ -41,10 +41,10 @@ struct assoc_array_ops { /* Is this the object we're looking for? */ bool (*compare_object)(const void *object, const void *index_key); - /* How different are two objects, to a bit position in their keys? (or - * -1 if they're the same) + /* How different is an object from an index key, to a bit position in + * their keys? (or -1 if they're the same) */ - int (*diff_objects)(const void *a, const void *b); + int (*diff_objects)(const void *object, const void *index_key); /* Method to free an object. */ void (*free_object)(void *object); diff --git a/lib/assoc_array.c b/lib/assoc_array.c index 17edeaf1918..1b6a44f1ec3 100644 --- a/lib/assoc_array.c +++ b/lib/assoc_array.c @@ -759,8 +759,8 @@ all_leaves_cluster_together: pr_devel("all leaves cluster together\n"); diff = INT_MAX; for (i = 0; i < ASSOC_ARRAY_FAN_OUT; i++) { - int x = ops->diff_objects(assoc_array_ptr_to_leaf(edit->leaf), - assoc_array_ptr_to_leaf(node->slots[i])); + int x = ops->diff_objects(assoc_array_ptr_to_leaf(node->slots[i]), + index_key); if (x < diff) { BUG_ON(x < 0); diff = x; diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 0adbc77a59b..3dd8445cd48 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -279,12 +279,11 @@ static bool keyring_compare_object(const void *object, const void *data) * Compare the index keys of a pair of objects and determine the bit position * at which they differ - if they differ. */ -static int keyring_diff_objects(const void *_a, const void *_b) +static int keyring_diff_objects(const void *object, const void *data) { - const struct key *key_a = keyring_ptr_to_key(_a); - const struct key *key_b = keyring_ptr_to_key(_b); + const struct key *key_a = keyring_ptr_to_key(object); const struct keyring_index_key *a = &key_a->index_key; - const struct keyring_index_key *b = &key_b->index_key; + const struct keyring_index_key *b = data; unsigned long seg_a, seg_b; int level, i; -- cgit v1.2.3-70-g09d2 From 9c5e45df215b4788f7a41c983ce862d08a083c2d Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 2 Dec 2013 11:24:19 +0000 Subject: KEYS: Fix searching of nested keyrings If a keyring contains more than 16 keyrings (the capacity of a single node in the associative array) then those keyrings are split over multiple nodes arranged as a tree. If search_nested_keyrings() is called to search the keyring then it will attempt to manually walk over just the 0 branch of the associative array tree where all the keyring links are stored. This works provided the key is found before the algorithm steps from one node containing keyrings to a child node or if there are sufficiently few keyring links that the keyrings are all in one node. However, if the algorithm does need to step from a node to a child node, it doesn't change the node pointer unless a shortcut also gets transited. This means that the algorithm will keep scanning the same node over and over again without terminating and without returning. To fix this, move the internal-pointer-to-node translation from inside the shortcut transit handler so that it applies it to node arrival as well. This can be tested by: r=`keyctl newring sandbox @s` for ((i=0; i<=16; i++)); do keyctl newring ring$i $r; done for ((i=0; i<=16; i++)); do keyctl add user a$i a %:ring$i; done for ((i=0; i<=16; i++)); do keyctl search $r user a$i; done for ((i=17; i<=20; i++)); do keyctl search $r user a$i; done The searches should all complete successfully (or with an error for 17-20), but instead one or more of them will hang. Signed-off-by: David Howells Tested-by: Stephen Gallagher --- security/keys/keyring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'security/keys') diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 3dd8445cd48..d46cbc5e335 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -690,8 +690,8 @@ descend_to_node: smp_read_barrier_depends(); ptr = ACCESS_ONCE(shortcut->next_node); BUG_ON(!assoc_array_ptr_is_node(ptr)); - node = assoc_array_ptr_to_node(ptr); } + node = assoc_array_ptr_to_node(ptr); begin_node: kdebug("begin_node"); -- cgit v1.2.3-70-g09d2 From c7277090927a5e71871e799a355ed2940f6c8fc6 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Mon, 2 Dec 2013 11:24:19 +0000 Subject: security: shmem: implement kernel private shmem inodes We have a problem where the big_key key storage implementation uses a shmem backed inode to hold the key contents. Because of this detail of implementation LSM checks are being done between processes trying to read the keys and the tmpfs backed inode. The LSM checks are already being handled on the key interface level and should not be enforced at the inode level (since the inode is an implementation detail, not a part of the security model) This patch implements a new function shmem_kernel_file_setup() which returns the equivalent to shmem_file_setup() only the underlying inode has S_PRIVATE set. This means that all LSM checks for the inode in question are skipped. It should only be used for kernel internal operations where the inode is not exposed to userspace without proper LSM checking. It is possible that some other users of shmem_file_setup() should use the new interface, but this has not been explored. Reproducing this bug is a little bit difficult. The steps I used on Fedora are: (1) Turn off selinux enforcing: setenforce 0 (2) Create a huge key k=`dd if=/dev/zero bs=8192 count=1 | keyctl padd big_key test-key @s` (3) Access the key in another context: runcon system_u:system_r:httpd_t:s0-s0:c0.c1023 keyctl print $k >/dev/null (4) Examine the audit logs: ausearch -m AVC -i --subject httpd_t | audit2allow If the last command's output includes a line that looks like: allow httpd_t user_tmpfs_t:file { open read }; There was an inode check between httpd and the tmpfs filesystem. With this patch no such denial will be seen. (NOTE! you should clear your audit log if you have tested for this previously) (Please return you box to enforcing) Signed-off-by: Eric Paris Signed-off-by: David Howells cc: Hugh Dickins cc: linux-mm@kvack.org --- include/linux/shmem_fs.h | 2 ++ mm/shmem.c | 36 +++++++++++++++++++++++++++++------- security/keys/big_key.c | 2 +- 3 files changed, 32 insertions(+), 8 deletions(-) (limited to 'security/keys') diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index 30aa0dc60d7..9d55438bc4a 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -47,6 +47,8 @@ extern int shmem_init(void); extern int shmem_fill_super(struct super_block *sb, void *data, int silent); extern struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags); +extern struct file *shmem_kernel_file_setup(const char *name, loff_t size, + unsigned long flags); extern int shmem_zero_setup(struct vm_area_struct *); extern int shmem_lock(struct file *file, int lock, struct user_struct *user); extern void shmem_unlock_mapping(struct address_space *mapping); diff --git a/mm/shmem.c b/mm/shmem.c index 8297623fcae..902a14842b7 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2918,13 +2918,8 @@ static struct dentry_operations anon_ops = { .d_dname = simple_dname }; -/** - * shmem_file_setup - get an unlinked file living in tmpfs - * @name: name for dentry (to be seen in /proc//maps - * @size: size to be set for the file - * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size - */ -struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) +static struct file *__shmem_file_setup(const char *name, loff_t size, + unsigned long flags, unsigned int i_flags) { struct file *res; struct inode *inode; @@ -2957,6 +2952,7 @@ struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags if (!inode) goto put_dentry; + inode->i_flags |= i_flags; d_instantiate(path.dentry, inode); inode->i_size = size; clear_nlink(inode); /* It is unlinked */ @@ -2977,6 +2973,32 @@ put_memory: shmem_unacct_size(flags, size); return res; } + +/** + * shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be + * kernel internal. There will be NO LSM permission checks against the + * underlying inode. So users of this interface must do LSM checks at a + * higher layer. The one user is the big_key implementation. LSM checks + * are provided at the key level rather than the inode level. + * @name: name for dentry (to be seen in /proc//maps + * @size: size to be set for the file + * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size + */ +struct file *shmem_kernel_file_setup(const char *name, loff_t size, unsigned long flags) +{ + return __shmem_file_setup(name, size, flags, S_PRIVATE); +} + +/** + * shmem_file_setup - get an unlinked file living in tmpfs + * @name: name for dentry (to be seen in /proc//maps + * @size: size to be set for the file + * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size + */ +struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) +{ + return __shmem_file_setup(name, size, flags, 0); +} EXPORT_SYMBOL_GPL(shmem_file_setup); /** diff --git a/security/keys/big_key.c b/security/keys/big_key.c index 7f44c3207a9..8137b27d641 100644 --- a/security/keys/big_key.c +++ b/security/keys/big_key.c @@ -70,7 +70,7 @@ int big_key_instantiate(struct key *key, struct key_preparsed_payload *prep) * * TODO: Encrypt the stored data with a temporary key. */ - file = shmem_file_setup("", datalen, 0); + file = shmem_kernel_file_setup("", datalen, 0); if (IS_ERR(file)) { ret = PTR_ERR(file); goto err_quota; -- cgit v1.2.3-70-g09d2