diff options
Diffstat (limited to 'security/keys')
| -rw-r--r-- | security/keys/key.c | 94 | ||||
| -rw-r--r-- | security/keys/keyctl.c | 23 | ||||
| -rw-r--r-- | security/keys/keyring.c | 245 | ||||
| -rw-r--r-- | security/keys/proc.c | 21 | ||||
| -rw-r--r-- | security/keys/process_keys.c | 12 | ||||
| -rw-r--r-- | security/keys/request_key.c | 32 | ||||
| -rw-r--r-- | security/keys/user_defined.c | 85 |
7 files changed, 289 insertions, 223 deletions
diff --git a/security/keys/key.c b/security/keys/key.c index 59402c84320..1fdfccb3fe4 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -294,7 +294,6 @@ struct key *key_alloc(struct key_type *type, const char *desc, } atomic_set(&key->usage, 1); - rwlock_init(&key->lock); init_rwsem(&key->sem); key->type = type; key->user = user; @@ -308,7 +307,7 @@ struct key *key_alloc(struct key_type *type, const char *desc, key->payload.data = NULL; if (!not_in_quota) - key->flags |= KEY_FLAG_IN_QUOTA; + key->flags |= 1 << KEY_FLAG_IN_QUOTA; memset(&key->type_data, 0, sizeof(key->type_data)); @@ -359,7 +358,7 @@ int key_payload_reserve(struct key *key, size_t datalen) key_check(key); /* contemplate the quota adjustment */ - if (delta != 0 && key->flags & KEY_FLAG_IN_QUOTA) { + if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { spin_lock(&key->user->lock); if (delta > 0 && @@ -405,23 +404,17 @@ static int __key_instantiate_and_link(struct key *key, down_write(&key_construction_sem); /* can't instantiate twice */ - if (!(key->flags & KEY_FLAG_INSTANTIATED)) { + if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { /* instantiate the key */ ret = key->type->instantiate(key, data, datalen); if (ret == 0) { /* mark the key as being instantiated */ - write_lock(&key->lock); - atomic_inc(&key->user->nikeys); - key->flags |= KEY_FLAG_INSTANTIATED; + set_bit(KEY_FLAG_INSTANTIATED, &key->flags); - if (key->flags & KEY_FLAG_USER_CONSTRUCT) { - key->flags &= ~KEY_FLAG_USER_CONSTRUCT; + if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) awaken = 1; - } - - write_unlock(&key->lock); /* and link it into the destination keyring */ if (keyring) @@ -486,21 +479,17 @@ int key_negate_and_link(struct key *key, down_write(&key_construction_sem); /* can't instantiate twice */ - if (!(key->flags & KEY_FLAG_INSTANTIATED)) { + if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { /* mark the key as being negatively instantiated */ - write_lock(&key->lock); - atomic_inc(&key->user->nikeys); - key->flags |= KEY_FLAG_INSTANTIATED | KEY_FLAG_NEGATIVE; + set_bit(KEY_FLAG_NEGATIVE, &key->flags); + set_bit(KEY_FLAG_INSTANTIATED, &key->flags); now = current_kernel_time(); key->expiry = now.tv_sec + timeout; - if (key->flags & KEY_FLAG_USER_CONSTRUCT) { - key->flags &= ~KEY_FLAG_USER_CONSTRUCT; + if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) awaken = 1; - } - write_unlock(&key->lock); ret = 0; /* and link it into the destination keyring */ @@ -553,8 +542,10 @@ static void key_cleanup(void *data) rb_erase(&key->serial_node, &key_serial_tree); spin_unlock(&key_serial_lock); + key_check(key); + /* deal with the user's key tracking and quota */ - if (key->flags & KEY_FLAG_IN_QUOTA) { + if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { spin_lock(&key->user->lock); key->user->qnkeys--; key->user->qnbytes -= key->quotalen; @@ -562,7 +553,7 @@ static void key_cleanup(void *data) } atomic_dec(&key->user->nkeys); - if (key->flags & KEY_FLAG_INSTANTIATED) + if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) atomic_dec(&key->user->nikeys); key_user_put(key->user); @@ -631,9 +622,9 @@ struct key *key_lookup(key_serial_t id) goto error; found: - /* pretent doesn't exist if it's dead */ + /* pretend it doesn't exist if it's dead */ if (atomic_read(&key->usage) == 0 || - (key->flags & KEY_FLAG_DEAD) || + test_bit(KEY_FLAG_DEAD, &key->flags) || key->type == &key_type_dead) goto not_found; @@ -708,12 +699,9 @@ static inline struct key *__key_update(struct key *key, const void *payload, ret = key->type->update(key, payload, plen); - if (ret == 0) { + if (ret == 0) /* updating a negative key instantiates it */ - write_lock(&key->lock); - key->flags &= ~KEY_FLAG_NEGATIVE; - write_unlock(&key->lock); - } + clear_bit(KEY_FLAG_NEGATIVE, &key->flags); up_write(&key->sem); @@ -841,12 +829,9 @@ int key_update(struct key *key, const void *payload, size_t plen) down_write(&key->sem); ret = key->type->update(key, payload, plen); - if (ret == 0) { + if (ret == 0) /* updating a negative key instantiates it */ - write_lock(&key->lock); - key->flags &= ~KEY_FLAG_NEGATIVE; - write_unlock(&key->lock); - } + clear_bit(KEY_FLAG_NEGATIVE, &key->flags); up_write(&key->sem); } @@ -892,10 +877,7 @@ struct key *key_duplicate(struct key *source, const char *desc) goto error2; atomic_inc(&key->user->nikeys); - - write_lock(&key->lock); - key->flags |= KEY_FLAG_INSTANTIATED; - write_unlock(&key->lock); + set_bit(KEY_FLAG_INSTANTIATED, &key->flags); error_k: up_read(&key_types_sem); @@ -922,9 +904,7 @@ void key_revoke(struct key *key) /* make sure no one's trying to change or use the key when we mark * it */ down_write(&key->sem); - write_lock(&key->lock); - key->flags |= KEY_FLAG_REVOKED; - write_unlock(&key->lock); + set_bit(KEY_FLAG_REVOKED, &key->flags); up_write(&key->sem); } /* end key_revoke() */ @@ -975,24 +955,33 @@ void unregister_key_type(struct key_type *ktype) /* withdraw the key type */ list_del_init(&ktype->link); - /* need to withdraw all keys of this type */ + /* mark all the keys of this type dead */ spin_lock(&key_serial_lock); for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { key = rb_entry(_n, struct key, serial_node); - if (key->type != ktype) - continue; + if (key->type == ktype) + key->type = &key_type_dead; + } + + spin_unlock(&key_serial_lock); + + /* make sure everyone revalidates their keys */ + synchronize_kernel(); + + /* we should now be able to destroy the payloads of all the keys of + * this type with impunity */ + spin_lock(&key_serial_lock); - write_lock(&key->lock); - key->type = &key_type_dead; - write_unlock(&key->lock); + for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) { + key = rb_entry(_n, struct key, serial_node); - /* there shouldn't be anyone looking at the description or - * payload now */ - if (ktype->destroy) - ktype->destroy(key); - memset(&key->payload, 0xbd, sizeof(key->payload)); + if (key->type == ktype) { + if (ktype->destroy) + ktype->destroy(key); + memset(&key->payload, 0xbd, sizeof(key->payload)); + } } spin_unlock(&key_serial_lock); @@ -1037,4 +1026,5 @@ void __init key_init(void) /* link the two root keyrings together */ key_link(&root_session_keyring, &root_user_keyring); + } /* end key_init() */ diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index dc0011b3fac..cedb7326de2 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -728,7 +728,6 @@ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid) /* make the changes with the locks held to prevent chown/chown races */ ret = -EACCES; down_write(&key->sem); - write_lock(&key->lock); if (!capable(CAP_SYS_ADMIN)) { /* only the sysadmin can chown a key to some other UID */ @@ -755,7 +754,6 @@ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid) ret = 0; no_access: - write_unlock(&key->lock); up_write(&key->sem); key_put(key); error: @@ -784,26 +782,19 @@ long keyctl_setperm_key(key_serial_t id, key_perm_t perm) goto error; } - /* make the changes with the locks held to prevent chown/chmod - * races */ + /* make the changes with the locks held to prevent chown/chmod races */ ret = -EACCES; down_write(&key->sem); - write_lock(&key->lock); - /* if we're not the sysadmin, we can only chmod a key that we - * own */ - if (!capable(CAP_SYS_ADMIN) && key->uid != current->fsuid) - goto no_access; - - /* changing the permissions mask */ - key->perm = perm; - ret = 0; + /* if we're not the sysadmin, we can only change a key that we own */ + if (capable(CAP_SYS_ADMIN) || key->uid == current->fsuid) { + key->perm = perm; + ret = 0; + } - no_access: - write_unlock(&key->lock); up_write(&key->sem); key_put(key); - error: +error: return ret; } /* end keyctl_setperm_key() */ diff --git a/security/keys/keyring.c b/security/keys/keyring.c index e2ab4f8e748..c9a5de19748 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -132,10 +132,17 @@ static int keyring_duplicate(struct key *keyring, const struct key *source) (PAGE_SIZE - sizeof(*klist)) / sizeof(struct key); ret = 0; - sklist = source->payload.subscriptions; - if (sklist && sklist->nkeys > 0) { + /* find out how many keys are currently linked */ + rcu_read_lock(); + sklist = rcu_dereference(source->payload.subscriptions); + max = 0; + if (sklist) max = sklist->nkeys; + rcu_read_unlock(); + + /* allocate a new payload and stuff load with key links */ + if (max > 0) { BUG_ON(max > limit); max = (max + 3) & ~3; @@ -148,6 +155,10 @@ static int keyring_duplicate(struct key *keyring, const struct key *source) if (!klist) goto error; + /* set links */ + rcu_read_lock(); + sklist = rcu_dereference(source->payload.subscriptions); + klist->maxkeys = max; klist->nkeys = sklist->nkeys; memcpy(klist->keys, @@ -157,7 +168,9 @@ static int keyring_duplicate(struct key *keyring, const struct key *source) for (loop = klist->nkeys - 1; loop >= 0; loop--) atomic_inc(&klist->keys[loop]->usage); - keyring->payload.subscriptions = klist; + rcu_read_unlock(); + + rcu_assign_pointer(keyring->payload.subscriptions, klist); ret = 0; } @@ -192,7 +205,7 @@ static void keyring_destroy(struct key *keyring) write_unlock(&keyring_name_lock); } - klist = keyring->payload.subscriptions; + klist = rcu_dereference(keyring->payload.subscriptions); if (klist) { for (loop = klist->nkeys - 1; loop >= 0; loop--) key_put(klist->keys[loop]); @@ -216,17 +229,20 @@ static void keyring_describe(const struct key *keyring, struct seq_file *m) seq_puts(m, "[anon]"); } - klist = keyring->payload.subscriptions; + rcu_read_lock(); + klist = rcu_dereference(keyring->payload.subscriptions); if (klist) seq_printf(m, ": %u/%u", klist->nkeys, klist->maxkeys); else seq_puts(m, ": empty"); + rcu_read_unlock(); } /* end keyring_describe() */ /*****************************************************************************/ /* * read a list of key IDs from the keyring's contents + * - the keyring's semaphore is read-locked */ static long keyring_read(const struct key *keyring, char __user *buffer, size_t buflen) @@ -237,7 +253,7 @@ static long keyring_read(const struct key *keyring, int loop, ret; ret = 0; - klist = keyring->payload.subscriptions; + klist = rcu_dereference(keyring->payload.subscriptions); if (klist) { /* calculate how much data we could return */ @@ -320,7 +336,7 @@ struct key *keyring_search_aux(struct key *keyring, key_match_func_t match) { struct { - struct key *keyring; + struct keyring_list *keylist; int kix; } stack[KEYRING_SEARCH_MAX_DEPTH]; @@ -328,10 +344,12 @@ struct key *keyring_search_aux(struct key *keyring, struct timespec now; struct key *key; long err; - int sp, psp, kix; + int sp, kix; key_check(keyring); + rcu_read_lock(); + /* top keyring must have search permission to begin the search */ key = ERR_PTR(-EACCES); if (!key_permission(keyring, KEY_SEARCH)) @@ -347,11 +365,10 @@ struct key *keyring_search_aux(struct key *keyring, /* start processing a new keyring */ descend: - read_lock(&keyring->lock); - if (keyring->flags & KEY_FLAG_REVOKED) + if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) goto not_this_keyring; - keylist = keyring->payload.subscriptions; + keylist = rcu_dereference(keyring->payload.subscriptions); if (!keylist) goto not_this_keyring; @@ -364,7 +381,7 @@ struct key *keyring_search_aux(struct key *keyring, continue; /* skip revoked keys and expired keys */ - if (key->flags & KEY_FLAG_REVOKED) + if (test_bit(KEY_FLAG_REVOKED, &key->flags)) continue; if (key->expiry && now.tv_sec >= key->expiry) @@ -379,7 +396,7 @@ struct key *keyring_search_aux(struct key *keyring, continue; /* we set a different error code if we find a negative key */ - if (key->flags & KEY_FLAG_NEGATIVE) { + if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) { err = -ENOKEY; continue; } @@ -390,48 +407,37 @@ struct key *keyring_search_aux(struct key *keyring, /* search through the keyrings nested in this one */ kix = 0; ascend: - while (kix < keylist->nkeys) { + for (; kix < keylist->nkeys; kix++) { key = keylist->keys[kix]; if (key->type != &key_type_keyring) - goto next; + continue; /* recursively search nested keyrings * - only search keyrings for which we have search permission */ if (sp >= KEYRING_SEARCH_MAX_DEPTH) - goto next; + continue; if (!key_permission(key, KEY_SEARCH)) - goto next; - - /* evade loops in the keyring tree */ - for (psp = 0; psp < sp; psp++) - if (stack[psp].keyring == keyring) - goto next; + continue; /* stack the current position */ - stack[sp].keyring = keyring; + stack[sp].keylist = keylist; stack[sp].kix = kix; sp++; /* begin again with the new keyring */ keyring = key; goto descend; - - next: - kix++; } /* the keyring we're looking at was disqualified or didn't contain a * matching key */ not_this_keyring: - read_unlock(&keyring->lock); - if (sp > 0) { /* resume the processing of a keyring higher up in the tree */ sp--; - keyring = stack[sp].keyring; - keylist = keyring->payload.subscriptions; + keylist = stack[sp].keylist; kix = stack[sp].kix + 1; goto ascend; } @@ -442,16 +448,9 @@ struct key *keyring_search_aux(struct key *keyring, /* we found a viable match */ found: atomic_inc(&key->usage); - read_unlock(&keyring->lock); - - /* unwind the keyring stack */ - while (sp > 0) { - sp--; - read_unlock(&stack[sp].keyring->lock); - } - key_check(key); error: + rcu_read_unlock(); return key; } /* end keyring_search_aux() */ @@ -489,7 +488,9 @@ struct key *__keyring_search_one(struct key *keyring, struct key *key; int loop; - klist = keyring->payload.subscriptions; + rcu_read_lock(); + + klist = rcu_dereference(keyring->payload.subscriptions); if (klist) { for (loop = 0; loop < klist->nkeys; loop++) { key = klist->keys[loop]; @@ -497,7 +498,7 @@ struct key *__keyring_search_one(struct key *keyring, if (key->type == ktype && key->type->match(key, description) && key_permission(key, perm) && - !(key->flags & KEY_FLAG_REVOKED) + !test_bit(KEY_FLAG_REVOKED, &key->flags) ) goto found; } @@ -509,6 +510,7 @@ struct key *__keyring_search_one(struct key *keyring, found: atomic_inc(&key->usage); error: + rcu_read_unlock(); return key; } /* end __keyring_search_one() */ @@ -540,7 +542,7 @@ struct key *find_keyring_by_name(const char *name, key_serial_t bound) &keyring_name_hash[bucket], type_data.link ) { - if (keyring->flags & KEY_FLAG_REVOKED) + if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) continue; if (strcmp(keyring->description, name) != 0) @@ -579,7 +581,7 @@ struct key *find_keyring_by_name(const char *name, key_serial_t bound) static int keyring_detect_cycle(struct key *A, struct key *B) { struct { - struct key *subtree; + struct keyring_list *keylist; int kix; } stack[KEYRING_SEARCH_MAX_DEPTH]; @@ -587,20 +589,21 @@ static int keyring_detect_cycle(struct key *A, struct key *B) struct key *subtree, *key; int sp, kix, ret; + rcu_read_lock(); + ret = -EDEADLK; if (A == B) - goto error; + goto cycle_detected; subtree = B; sp = 0; /* start processing a new keyring */ descend: - read_lock(&subtree->lock); - if (subtree->flags & KEY_FLAG_REVOKED) + if (test_bit(KEY_FLAG_REVOKED, &subtree->flags)) goto not_this_keyring; - keylist = subtree->payload.subscriptions; + keylist = rcu_dereference(subtree->payload.subscriptions); if (!keylist) goto not_this_keyring; kix = 0; @@ -619,7 +622,7 @@ static int keyring_detect_cycle(struct key *A, struct key *B) goto too_deep; /* stack the current position */ - stack[sp].subtree = subtree; + stack[sp].keylist = keylist; stack[sp].kix = kix; sp++; @@ -632,13 +635,10 @@ static int keyring_detect_cycle(struct key *A, struct key *B) /* the keyring we're looking at was disqualified or didn't contain a * matching key */ not_this_keyring: - read_unlock(&subtree->lock); - if (sp > 0) { /* resume the checking of a keyring higher up in the tree */ sp--; - subtree = stack[sp].subtree; - keylist = subtree->payload.subscriptions; + keylist = stack[sp].keylist; kix = stack[sp].kix + 1; goto ascend; } @@ -646,30 +646,36 @@ static int keyring_detect_cycle(struct key *A, struct key *B) ret = 0; /* no cycles detected */ error: + rcu_read_unlock(); return ret; too_deep: ret = -ELOOP; - goto error_unwind; + goto error; + cycle_detected: ret = -EDEADLK; - error_unwind: - read_unlock(&subtree->lock); - - /* unwind the keyring stack */ - while (sp > 0) { - sp--; - read_unlock(&stack[sp].subtree->lock); - } - goto error; } /* end keyring_detect_cycle() */ /*****************************************************************************/ /* + * dispose of a keyring list after the RCU grace period + */ +static void keyring_link_rcu_disposal(struct rcu_head *rcu) +{ + struct keyring_list *klist = + container_of(rcu, struct keyring_list, rcu); + + kfree(klist); + +} /* end keyring_link_rcu_disposal() */ + +/*****************************************************************************/ +/* * link a key into to a keyring - * - must be called with the keyring's semaphore held + * - must be called with the keyring's semaphore write-locked */ int __key_link(struct key *keyring, struct key *key) { @@ -679,7 +685,7 @@ int __key_link(struct key *keyring, struct key *key) int ret; ret = -EKEYREVOKED; - if (keyring->flags & KEY_FLAG_REVOKED) + if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) goto error; ret = -ENOTDIR; @@ -710,9 +716,10 @@ int __key_link(struct key *keyring, struct key *key) /* there's sufficient slack space to add directly */ atomic_inc(&key->usage); - write_lock(&keyring->lock); - klist->keys[klist->nkeys++] = key; - write_unlock(&keyring->lock); + klist->keys[klist->nkeys] = key; + smp_wmb(); + klist->nkeys++; + smp_wmb(); ret = 0; } @@ -723,6 +730,8 @@ int __key_link(struct key *keyring, struct key *key) max += klist->maxkeys; ret = -ENFILE; + if (max > 65535) + goto error3; size = sizeof(*klist) + sizeof(*key) * max; if (size > PAGE_SIZE) goto error3; @@ -743,14 +752,13 @@ int __key_link(struct key *keyring, struct key *key) /* add the key into the new space */ atomic_inc(&key->usage); - - write_lock(&keyring->lock); - keyring->payload.subscriptions = nklist; nklist->keys[nklist->nkeys++] = key; - write_unlock(&keyring->lock); + + rcu_assign_pointer(keyring->payload.subscriptions, nklist); /* dispose of the old keyring list */ - kfree(klist); + if (klist) + call_rcu(&klist->rcu, keyring_link_rcu_disposal); ret = 0; } @@ -791,11 +799,26 @@ EXPORT_SYMBOL(key_link); /*****************************************************************************/ /* + * 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); + + key_put(klist->keys[klist->delkey]); + kfree(klist); + +} /* end keyring_unlink_rcu_disposal() */ + +/*****************************************************************************/ +/* * unlink the first link to a key from a keyring */ int key_unlink(struct key *keyring, struct key *key) { - struct keyring_list *klist; + struct keyring_list *klist, *nklist; int loop, ret; key_check(keyring); @@ -819,31 +842,45 @@ int key_unlink(struct key *keyring, struct key *key) ret = -ENOENT; goto error; - key_is_present: +key_is_present: + /* we need to copy the key list for RCU purposes */ + nklist = kmalloc(sizeof(*klist) + sizeof(*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(klist->keys[0])); + + if (loop < nklist->nkeys) + memcpy(&nklist->keys[loop], + &klist->keys[loop + 1], + (nklist->nkeys - loop) * sizeof(klist->keys[0])); + /* adjust the user's quota */ key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES); - /* shuffle down the key pointers - * - it might be worth shrinking the allocated memory, but that runs - * the risk of ENOMEM as we would have to copy - */ - write_lock(&keyring->lock); + rcu_assign_pointer(keyring->payload.subscriptions, nklist); - klist->nkeys--; - if (loop < klist->nkeys) - memcpy(&klist->keys[loop], - &klist->keys[loop + 1], - (klist->nkeys - loop) * sizeof(struct key *)); + up_write(&keyring->sem); - write_unlock(&keyring->lock); + /* schedule for later cleanup */ + klist->delkey = loop; + call_rcu(&klist->rcu, keyring_unlink_rcu_disposal); - up_write(&keyring->sem); - key_put(key); ret = 0; - error: +error: return ret; +nomem: + ret = -ENOMEM; + up_write(&keyring->sem); + goto error; } /* end key_unlink() */ @@ -851,13 +888,32 @@ 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(klist->keys[loop]); + + kfree(klist); + +} /* end keyring_clear_rcu_disposal() */ + +/*****************************************************************************/ +/* * clear the specified process keyring * - implements keyctl(KEYCTL_CLEAR) */ int keyring_clear(struct key *keyring) { struct keyring_list *klist; - int loop, ret; + int ret; ret = -ENOTDIR; if (keyring->type == &key_type_keyring) { @@ -870,20 +926,15 @@ int keyring_clear(struct key *keyring) key_payload_reserve(keyring, sizeof(struct keyring_list)); - write_lock(&keyring->lock); - keyring->payload.subscriptions = NULL; - write_unlock(&keyring->lock); + rcu_assign_pointer(keyring->payload.subscriptions, + NULL); } up_write(&keyring->sem); /* free the keys after the locks have been dropped */ - if (klist) { - for (loop = klist->nkeys - 1; loop >= 0; loop--) - key_put(klist->keys[loop]); - - kfree(klist); - } + if (klist) + call_rcu(&klist->rcu, keyring_clear_rcu_disposal); ret = 0; } diff --git a/security/keys/proc.c b/security/keys/proc.c index 91343b85c39..c55cf1fd082 100644 --- a/security/keys/proc.c +++ b/security/keys/proc.c @@ -140,7 +140,7 @@ static int proc_keys_show(struct seq_file *m, void *v) now = current_kernel_time(); - read_lock(&key->lock); + rcu_read_lock(); /* come up with a suitable timeout value */ if (key->expiry == 0) { @@ -164,14 +164,17 @@ static int proc_keys_show(struct seq_file *m, void *v) sprintf(xbuf, "%luw", timo / (60*60*24*7)); } +#define showflag(KEY, LETTER, FLAG) \ + (test_bit(FLAG, &(KEY)->flags) ? LETTER : '-') + seq_printf(m, "%08x %c%c%c%c%c%c %5d %4s %06x %5d %5d %-9.9s ", key->serial, - key->flags & KEY_FLAG_INSTANTIATED ? 'I' : '-', - key->flags & KEY_FLAG_REVOKED ? 'R' : '-', - key->flags & KEY_FLAG_DEAD ? 'D' : '-', - key->flags & KEY_FLAG_IN_QUOTA ? 'Q' : '-', - key->flags & KEY_FLAG_USER_CONSTRUCT ? 'U' : '-', - key->flags & KEY_FLAG_NEGATIVE ? 'N' : '-', + showflag(key, 'I', KEY_FLAG_INSTANTIATED), + showflag(key, 'R', KEY_FLAG_REVOKED), + showflag(key, 'D', KEY_FLAG_DEAD), + showflag(key, 'Q', KEY_FLAG_IN_QUOTA), + showflag(key, 'U', KEY_FLAG_USER_CONSTRUCT), + showflag(key, 'N', KEY_FLAG_NEGATIVE), atomic_read(&key->usage), xbuf, key->perm, @@ -179,11 +182,13 @@ static int proc_keys_show(struct seq_file *m, void *v) key->gid, key->type->name); +#undef showflag + if (key->type->describe) key->type->describe(key, m); seq_putc(m, '\n'); - read_unlock(&key->lock); + rcu_read_unlock(); return 0; diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c index 2eb0e471cd4..059c350cac4 100644 --- a/security/keys/process_keys.c +++ b/security/keys/process_keys.c @@ -38,10 +38,9 @@ struct key root_user_keyring = { .serial = 2, .type = &key_type_keyring, .user = &root_key_user, - .lock = RW_LOCK_UNLOCKED, .sem = __RWSEM_INITIALIZER(root_user_keyring.sem), .perm = KEY_USR_ALL, - .flags = KEY_FLAG_INSTANTIATED, + .flags = 1 << KEY_FLAG_INSTANTIATED, .description = "_uid.0", #ifdef KEY_DEBUGGING .magic = KEY_DEBUG_MAGIC, @@ -54,10 +53,9 @@ struct key root_session_keyring = { .serial = 1, .type = &key_type_keyring, .user = &root_key_user, - .lock = RW_LOCK_UNLOCKED, .sem = __RWSEM_INITIALIZER(root_session_keyring.sem), .perm = KEY_USR_ALL, - .flags = KEY_FLAG_INSTANTIATED, + .flags = 1 << KEY_FLAG_INSTANTIATED, .description = "_uid_ses.0", #ifdef KEY_DEBUGGING .magic = KEY_DEBUG_MAGIC, @@ -349,9 +347,7 @@ void key_fsuid_changed(struct task_struct *tsk) /* update the ownership of the thread keyring */ if (tsk->thread_keyring) { down_write(&tsk->thread_keyring->sem); - write_lock(&tsk->thread_keyring->lock); tsk->thread_keyring->uid = tsk->fsuid; - write_unlock(&tsk->thread_keyring->lock); up_write(&tsk->thread_keyring->sem); } @@ -366,9 +362,7 @@ void key_fsgid_changed(struct task_struct *tsk) /* update the ownership of the thread keyring */ if (tsk->thread_keyring) { down_write(&tsk->thread_keyring->sem); - write_lock(&tsk->thread_keyring->lock); tsk->thread_keyring->gid = tsk->fsgid; - write_unlock(&tsk->thread_keyring->lock); up_write(&tsk->thread_keyring->sem); } @@ -588,7 +582,7 @@ struct key *lookup_user_key(key_serial_t id, int create, int partial, } ret = -EIO; - if (!partial && !(key->flags & KEY_FLAG_INSTANTIATED)) + if (!partial && !test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) goto invalid_key; ret = -EACCES; diff --git a/security/keys/request_key.c b/security/keys/request_key.c index 9705b1aeba5..1f6c0940297 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -105,7 +105,7 @@ static struct key *__request_key_construction(struct key_type *type, struct key_construction cons; struct timespec now; struct key *key; - int ret, negative; + int ret, negated; /* create a key and add it to the queue */ key = key_alloc(type, description, @@ -113,9 +113,7 @@ static struct key *__request_key_construction(struct key_type *type, if (IS_ERR(key)) goto alloc_failed; - write_lock(&key->lock); - key->flags |= KEY_FLAG_USER_CONSTRUCT; - write_unlock(&key->lock); + set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags); cons.key = key; list_add_tail(&cons.link, &key->user->consq); @@ -130,7 +128,7 @@ static struct key *__request_key_construction(struct key_type *type, /* if the key wasn't instantiated, then we want to give an error */ ret = -ENOKEY; - if (!(key->flags & KEY_FLAG_INSTANTIATED)) + if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) goto request_failed; down_write(&key_construction_sem); @@ -139,7 +137,7 @@ static struct key *__request_key_construction(struct key_type *type, /* also give an error if the key was negatively instantiated */ check_not_negative: - if (key->flags & KEY_FLAG_NEGATIVE) { + if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) { key_put(key); key = ERR_PTR(-ENOKEY); } @@ -152,24 +150,23 @@ static struct key *__request_key_construction(struct key_type *type, * - remove from construction queue * - mark the key as dead */ - negative = 0; + negated = 0; down_write(&key_construction_sem); list_del(&cons.link); - write_lock(&key->lock); - key->flags &= ~KEY_FLAG_USER_CONSTRUCT; - /* check it didn't get instantiated between the check and the down */ - if (!(key->flags & KEY_FLAG_INSTANTIATED)) { - key->flags |= KEY_FLAG_INSTANTIATED | KEY_FLAG_NEGATIVE; - negative = 1; + if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { + set_bit(KEY_FLAG_NEGATIVE, &key->flags); + set_bit(KEY_FLAG_INSTANTIATED, &key->flags); + negated = 1; } - write_unlock(&key->lock); + clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags); + up_write(&key_construction_sem); - if (!negative) + if (!negated) goto check_not_negative; /* surprisingly, the key got * instantiated */ @@ -250,7 +247,7 @@ static struct key *request_key_construction(struct key_type *type, for (;;) { set_current_state(TASK_UNINTERRUPTIBLE); - if (!(ckey->flags & KEY_FLAG_USER_CONSTRUCT)) + if (!test_bit(KEY_FLAG_USER_CONSTRUCT, &ckey->flags)) break; schedule(); } @@ -339,7 +336,8 @@ int key_validate(struct key *key) if (key) { /* check it's still accessible */ ret = -EKEYREVOKED; - if (key->flags & (KEY_FLAG_REVOKED | KEY_FLAG_DEAD)) + if (test_bit(KEY_FLAG_REVOKED, &key->flags) || + test_bit(KEY_FLAG_DEAD, &key->flags)) goto error; /* check it hasn't expired */ diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c index 8d65b3a2812..c33d3614a0d 100644 --- a/security/keys/user_defined.c +++ b/security/keys/user_defined.c @@ -42,12 +42,19 @@ struct key_type key_type_user = { .read = user_read, }; +struct user_key_payload { + struct rcu_head rcu; /* RCU destructor */ + unsigned short datalen; /* length of this data */ + char data[0]; /* actual data */ +}; + /*****************************************************************************/ /* * instantiate a user defined key */ static int user_instantiate(struct key *key, const void *data, size_t datalen) { + struct user_key_payload *upayload; int ret; ret = -EINVAL; @@ -58,13 +65,15 @@ static int user_instantiate(struct key *key, const void *data, size_t datalen) if (ret < 0) goto error; - /* attach the data */ ret = -ENOMEM; - key->payload.data = kmalloc(datalen, GFP_KERNEL); - if (!key->payload.data) + upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); + if (!upayload) goto error; - memcpy(key->payload.data, data, datalen); + /* attach the data */ + upayload->datalen = datalen; + memcpy(upayload->data, data, datalen); + rcu_assign_pointer(key->payload.data, upayload); ret = 0; error: @@ -75,18 +84,25 @@ static int user_instantiate(struct key *key, const void *data, size_t datalen) /*****************************************************************************/ /* * duplicate a user defined key + * - both keys' semaphores are locked against further modification + * - the new key cannot yet be accessed */ static int user_duplicate(struct key *key, const struct key *source) { + struct user_key_payload *upayload, *spayload; int ret; /* just copy the payload */ ret = -ENOMEM; - key->payload.data = kmalloc(source->datalen, GFP_KERNEL); + upayload = kmalloc(sizeof(*upayload) + source->datalen, GFP_KERNEL); + if (upayload) { + spayload = rcu_dereference(source->payload.data); + BUG_ON(source->datalen != spayload->datalen); - if (key->payload.data) { - key->datalen = source->datalen; - memcpy(key->payload.data, source->payload.data, source->datalen); + upayload->datalen = key->datalen = spayload->datalen; + memcpy(upayload->data, spayload->data, key->datalen); + + key->payload.data = upayload; ret = 0; } @@ -96,40 +112,54 @@ static int user_duplicate(struct key *key, const struct key *source) /*****************************************************************************/ /* + * dispose of the old data from an updated user defined key + */ +static void user_update_rcu_disposal(struct rcu_head *rcu) +{ + struct user_key_payload *upayload; + + upayload = container_of(rcu, struct user_key_payload, rcu); + + kfree(upayload); + +} /* end user_update_rcu_disposal() */ + +/*****************************************************************************/ +/* * update a user defined key + * - the key's semaphore is write-locked */ static int user_update(struct key *key, const void *data, size_t datalen) { - void *new, *zap; + struct user_key_payload *upayload, *zap; int ret; ret = -EINVAL; if (datalen <= 0 || datalen > 32767 || !data) goto error; - /* copy the data */ + /* construct a replacement payload */ ret = -ENOMEM; - new = kmalloc(datalen, GFP_KERNEL); - if (!new) + upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); + if (!upayload) goto error; - memcpy(new, data, datalen); + upayload->datalen = datalen; + memcpy(upayload->data, data, datalen); /* check the quota and attach the new data */ - zap = new; - write_lock(&key->lock); + zap = upayload; ret = key_payload_reserve(key, datalen); if (ret == 0) { /* attach the new data, displacing the old */ zap = key->payload.data; - key->payload.data = new; + rcu_assign_pointer(key->payload.data, upayload); key->expiry = 0; } - write_unlock(&key->lock); - kfree(zap); + call_rcu(&zap->rcu, user_update_rcu_disposal); error: return ret; @@ -152,13 +182,15 @@ static int user_match(const struct key *key, const void *description) */ static void user_destroy(struct key *key) { - kfree(key->payload.data); + struct user_key_payload *upayload = key->payload.data; + + kfree(upayload); } /* end user_destroy() */ /*****************************************************************************/ /* - * describe the user + * describe the user key */ static void user_describe(const struct key *key, struct seq_file *m) { @@ -171,18 +203,23 @@ static void user_describe(const struct key *key, struct seq_file *m) /*****************************************************************************/ /* * read the key data + * - the key's semaphore is read-locked */ static long user_read(const struct key *key, char __user *buffer, size_t buflen) { - long ret = key->datalen; + struct user_key_payload *upayload; + long ret; + + upayload = rcu_dereference(key->payload.data); + ret = upayload->datalen; /* we can return the data as is */ if (buffer && buflen > 0) { - if (buflen > key->datalen) - buflen = key->datalen; + if (buflen > upayload->datalen) + buflen = upayload->datalen; - if (copy_to_user(buffer, key->payload.data, buflen) != 0) + if (copy_to_user(buffer, upayload->data, buflen) != 0) ret = -EFAULT; } |