diff options
Diffstat (limited to 'security/keys/keyctl.c')
| -rw-r--r-- | security/keys/keyctl.c | 749 |
1 files changed, 491 insertions, 258 deletions
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index 60924f6a52d..cd5bd0cef25 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -1,4 +1,4 @@ -/* keyctl.c: userspace keyctl operations +/* Userspace key control operations * * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) @@ -14,6 +14,7 @@ #include <linux/sched.h> #include <linux/slab.h> #include <linux/syscalls.h> +#include <linux/key.h> #include <linux/keyctl.h> #include <linux/fs.h> #include <linux/capability.h> @@ -21,6 +22,7 @@ #include <linux/err.h> #include <linux/vmalloc.h> #include <linux/security.h> +#include <linux/uio.h> #include <asm/uaccess.h> #include "internal.h" @@ -31,28 +33,27 @@ static int key_get_type_from_user(char *type, int ret; ret = strncpy_from_user(type, _type, len); - if (ret < 0) return ret; - if (ret == 0 || ret >= len) return -EINVAL; - if (type[0] == '.') return -EPERM; - type[len - 1] = '\0'; - return 0; } -/*****************************************************************************/ /* - * extract the description of a new key from userspace and either add it as a - * new key to the specified keyring or update a matching key in that keyring - * - the keyring must be writable - * - returns the new key's serial number - * - implements add_key() + * Extract the description of a new key from userspace and either add it as a + * new key to the specified keyring or update a matching key in that keyring. + * + * If the description is NULL or an empty string, the key type is asked to + * generate one from the payload. + * + * The keyring must be writable so that we can attach the key to it. + * + * If successful, the new key's serial number is returned, otherwise an error + * code is returned. */ SYSCALL_DEFINE5(add_key, const char __user *, _type, const char __user *, _description, @@ -75,10 +76,17 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type, if (ret < 0) goto error; - description = strndup_user(_description, PAGE_SIZE); - if (IS_ERR(description)) { - ret = PTR_ERR(description); - goto error; + description = NULL; + if (_description) { + description = strndup_user(_description, PAGE_SIZE); + if (IS_ERR(description)) { + ret = PTR_ERR(description); + goto error; + } + if (!*description) { + kfree(description); + description = NULL; + } } /* pull the payload in if one was supplied */ @@ -87,7 +95,7 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type, vm = false; if (_payload) { ret = -ENOMEM; - payload = kmalloc(plen, GFP_KERNEL); + payload = kmalloc(plen, GFP_KERNEL | __GFP_NOWARN); if (!payload) { if (plen <= PAGE_SIZE) goto error2; @@ -103,7 +111,7 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type, } /* find the target keyring (which must be writable) */ - keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); + keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error3; @@ -132,19 +140,20 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type, kfree(description); error: return ret; +} -} /* end sys_add_key() */ - -/*****************************************************************************/ /* - * search the process keyrings for a matching key - * - nested keyrings may also be searched if they have Search permission - * - if a key is found, it will be attached to the destination keyring if - * there's one specified - * - /sbin/request-key will be invoked if _callout_info is non-NULL - * - the _callout_info string will be passed to /sbin/request-key - * - if the _callout_info string is empty, it will be rendered as "-" - * - implements request_key() + * Search the process keyrings and keyring trees linked from those for a + * matching key. Keyrings must have appropriate Search permission to be + * searched. + * + * If a key is found, it will be attached to the destination keyring if there's + * one specified and the serial number of the key will be returned. + * + * If no key is found, /sbin/request-key will be invoked if _callout_info is + * non-NULL in an attempt to create a key. The _callout_info string will be + * passed to /sbin/request-key to aid with completing the request. If the + * _callout_info string is "" then it will be changed to "-". */ SYSCALL_DEFINE4(request_key, const char __user *, _type, const char __user *, _description, @@ -186,7 +195,7 @@ SYSCALL_DEFINE4(request_key, const char __user *, _type, dest_ref = NULL; if (destringid) { dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE, - KEY_WRITE); + KEY_NEED_WRITE); if (IS_ERR(dest_ref)) { ret = PTR_ERR(dest_ref); goto error3; @@ -209,8 +218,14 @@ SYSCALL_DEFINE4(request_key, const char __user *, _type, goto error5; } + /* wait for the key to finish being constructed */ + ret = wait_for_key_construction(key, 1); + if (ret < 0) + goto error6; + ret = key->serial; +error6: key_put(key); error5: key_type_put(ktype); @@ -222,14 +237,14 @@ error2: kfree(description); error: return ret; +} -} /* end sys_request_key() */ - -/*****************************************************************************/ /* - * get the ID of the specified process keyring - * - the keyring must have search permission to be found - * - implements keyctl(KEYCTL_GET_KEYRING_ID) + * Get the ID of the specified process keyring. + * + * The requested keyring must have search permission to be found. + * + * If successful, the ID of the requested keyring will be returned. */ long keyctl_get_keyring_ID(key_serial_t id, int create) { @@ -238,7 +253,7 @@ long keyctl_get_keyring_ID(key_serial_t id, int create) long ret; lflags = create ? KEY_LOOKUP_CREATE : 0; - key_ref = lookup_user_key(id, lflags, KEY_SEARCH); + key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error; @@ -248,13 +263,17 @@ long keyctl_get_keyring_ID(key_serial_t id, int create) key_ref_put(key_ref); error: return ret; +} -} /* end keyctl_get_keyring_ID() */ - -/*****************************************************************************/ /* - * join the session keyring - * - implements keyctl(KEYCTL_JOIN_SESSION_KEYRING) + * Join a (named) session keyring. + * + * Create and join an anonymous session keyring or join a named session + * keyring, creating it if necessary. A named session keyring must have Search + * permission for it to be joined. Session keyrings without this permit will + * be skipped over. + * + * If successful, the ID of the joined session keyring will be returned. */ long keyctl_join_session_keyring(const char __user *_name) { @@ -277,14 +296,17 @@ long keyctl_join_session_keyring(const char __user *_name) error: return ret; +} -} /* end keyctl_join_session_keyring() */ - -/*****************************************************************************/ /* - * update a key's data payload - * - the key must be writable - * - implements keyctl(KEYCTL_UPDATE) + * Update a key's data payload from the given data. + * + * The key must grant the caller Write permission and the key type must support + * updating for this to work. A negative key can be positively instantiated + * with this call. + * + * If successful, 0 will be returned. If the key type does not support + * updating, then -EOPNOTSUPP will be returned. */ long keyctl_update_key(key_serial_t id, const void __user *_payload, @@ -312,7 +334,7 @@ long keyctl_update_key(key_serial_t id, } /* find the target key (which must be writable) */ - key_ref = lookup_user_key(id, 0, KEY_WRITE); + key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error2; @@ -326,26 +348,29 @@ error2: kfree(payload); error: return ret; +} -} /* end keyctl_update_key() */ - -/*****************************************************************************/ /* - * revoke a key - * - the key must be writable - * - implements keyctl(KEYCTL_REVOKE) + * Revoke a key. + * + * The key must be grant the caller Write or Setattr permission for this to + * work. The key type should give up its quota claim when revoked. The key + * and any links to the key will be automatically garbage collected after a + * certain amount of time (/proc/sys/kernel/keys/gc_delay). + * + * If successful, 0 is returned. */ long keyctl_revoke_key(key_serial_t id) { key_ref_t key_ref; long ret; - key_ref = lookup_user_key(id, 0, KEY_WRITE); + key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); if (ret != -EACCES) goto error; - key_ref = lookup_user_key(id, 0, KEY_SETATTR); + key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error; @@ -358,53 +383,100 @@ long keyctl_revoke_key(key_serial_t id) key_ref_put(key_ref); error: return ret; +} + +/* + * Invalidate a key. + * + * The key must be grant the caller Invalidate permission for this to work. + * The key and any links to the key will be automatically garbage collected + * immediately. + * + * If successful, 0 is returned. + */ +long keyctl_invalidate_key(key_serial_t id) +{ + key_ref_t key_ref; + long ret; + + kenter("%d", id); + + key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH); + if (IS_ERR(key_ref)) { + ret = PTR_ERR(key_ref); + goto error; + } -} /* end keyctl_revoke_key() */ + key_invalidate(key_ref_to_ptr(key_ref)); + ret = 0; + + key_ref_put(key_ref); +error: + kleave(" = %ld", ret); + return ret; +} -/*****************************************************************************/ /* - * clear the specified process keyring - * - the keyring must be writable - * - implements keyctl(KEYCTL_CLEAR) + * Clear the specified keyring, creating an empty process keyring if one of the + * special keyring IDs is used. + * + * The keyring must grant the caller Write permission for this to work. If + * successful, 0 will be returned. */ long keyctl_keyring_clear(key_serial_t ringid) { key_ref_t keyring_ref; long ret; - keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); + keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); + + /* Root is permitted to invalidate certain special keyrings */ + if (capable(CAP_SYS_ADMIN)) { + keyring_ref = lookup_user_key(ringid, 0, 0); + if (IS_ERR(keyring_ref)) + goto error; + if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR, + &key_ref_to_ptr(keyring_ref)->flags)) + goto clear; + goto error_put; + } + goto error; } +clear: ret = keyring_clear(key_ref_to_ptr(keyring_ref)); - +error_put: key_ref_put(keyring_ref); error: return ret; +} -} /* end keyctl_keyring_clear() */ - -/*****************************************************************************/ /* - * link a key into a keyring - * - the keyring must be writable - * - the key must be linkable - * - implements keyctl(KEYCTL_LINK) + * Create a link from a keyring to a key if there's no matching key in the + * keyring, otherwise replace the link to the matching key with a link to the + * new key. + * + * The key must grant the caller Link permission and the the keyring must grant + * the caller Write permission. Furthermore, if an additional link is created, + * the keyring's quota will be extended. + * + * If successful, 0 will be returned. */ long keyctl_keyring_link(key_serial_t id, key_serial_t ringid) { key_ref_t keyring_ref, key_ref; long ret; - keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); + keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error; } - key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK); + key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error2; @@ -417,22 +489,23 @@ error2: key_ref_put(keyring_ref); error: return ret; +} -} /* end keyctl_keyring_link() */ - -/*****************************************************************************/ /* - * unlink the first attachment of a key from a keyring - * - the keyring must be writable - * - we don't need any permissions on the key - * - implements keyctl(KEYCTL_UNLINK) + * Unlink a key from a keyring. + * + * The keyring must grant the caller Write permission for this to work; the key + * itself need not grant the caller anything. If the last link to a key is + * removed then that key will be scheduled for destruction. + * + * If successful, 0 will be returned. */ long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid) { key_ref_t keyring_ref, key_ref; long ret; - keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE); + keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error; @@ -451,19 +524,20 @@ error2: key_ref_put(keyring_ref); error: return ret; +} -} /* end keyctl_keyring_unlink() */ - -/*****************************************************************************/ /* - * describe a user key - * - the key must have view permission - * - if there's a buffer, we place up to buflen bytes of data into it - * - unless there's an error, we return the amount of description available, - * irrespective of how much we may have copied - * - the description is formatted thus: + * Return a description of a key to userspace. + * + * The key must grant the caller View permission for this to work. + * + * If there's a buffer, we place up to buflen bytes of data into it formatted + * in the following way: + * * type;uid;gid;perm;description<NUL> - * - implements keyctl(KEYCTL_DESCRIBE) + * + * If successful, we return the amount of description available, irrespective + * of how much we may have copied into the buffer. */ long keyctl_describe_key(key_serial_t keyid, char __user *buffer, @@ -474,7 +548,7 @@ long keyctl_describe_key(key_serial_t keyid, char *tmpbuf; long ret; - key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW); + key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW); if (IS_ERR(key_ref)) { /* viewing a key under construction is permitted if we have the * authorisation token handy */ @@ -506,8 +580,8 @@ okay: ret = snprintf(tmpbuf, PAGE_SIZE - 1, "%s;%d;%d;%08x;%s", key->type->name, - key->uid, - key->gid, + from_kuid_munged(current_user_ns(), key->uid), + from_kgid_munged(current_user_ns(), key->gid), key->perm, key->description ?: ""); @@ -531,18 +605,17 @@ error2: key_ref_put(key_ref); error: return ret; +} -} /* end keyctl_describe_key() */ - -/*****************************************************************************/ /* - * search the specified keyring for a matching key - * - the start keyring must be searchable - * - nested keyrings may also be searched if they are searchable - * - only keys with search permission may be found - * - if a key is found, it will be attached to the destination keyring if - * there's one specified - * - implements keyctl(KEYCTL_SEARCH) + * Search the specified keyring and any keyrings it links to for a matching + * key. Only keyrings that grant the caller Search permission will be searched + * (this includes the starting keyring). Only keys with Search permission can + * be found. + * + * If successful, the found key will be linked to the destination keyring if + * supplied and the key has Link permission, and the found key ID will be + * returned. */ long keyctl_keyring_search(key_serial_t ringid, const char __user *_type, @@ -566,7 +639,7 @@ long keyctl_keyring_search(key_serial_t ringid, } /* get the keyring at which to begin the search */ - keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH); + keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error2; @@ -576,7 +649,7 @@ long keyctl_keyring_search(key_serial_t ringid, dest_ref = NULL; if (destringid) { dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE, - KEY_WRITE); + KEY_NEED_WRITE); if (IS_ERR(dest_ref)) { ret = PTR_ERR(dest_ref); goto error3; @@ -603,7 +676,7 @@ long keyctl_keyring_search(key_serial_t ringid, /* link the resulting key to the destination keyring if we can */ if (dest_ref) { - ret = key_permission(key_ref, KEY_LINK); + ret = key_permission(key_ref, KEY_NEED_LINK); if (ret < 0) goto error6; @@ -626,18 +699,17 @@ error2: kfree(description); error: return ret; +} -} /* end keyctl_keyring_search() */ - -/*****************************************************************************/ /* - * read a user key's payload - * - the keyring must be readable or the key must be searchable from the - * process's keyrings - * - if there's a buffer, we place up to buflen bytes of data into it - * - unless there's an error, we return the amount of data in the key, - * irrespective of how much we may have copied - * - implements keyctl(KEYCTL_READ) + * Read a key's payload. + * + * The key must either grant the caller Read permission, or it must grant the + * caller Search permission when searched for from the process keyrings. + * + * If successful, we place up to buflen bytes of data into the buffer, if one + * is provided, and return the amount of data that is available in the key, + * irrespective of how much we copied into the buffer. */ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen) { @@ -655,7 +727,7 @@ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen) key = key_ref_to_ptr(key_ref); /* see if we can read it directly */ - ret = key_permission(key_ref, KEY_READ); + ret = key_permission(key_ref, KEY_NEED_READ); if (ret == 0) goto can_read_key; if (ret != -EACCES) @@ -688,29 +760,46 @@ error2: key_put(key); error: return ret; +} -} /* end keyctl_read_key() */ - -/*****************************************************************************/ /* - * change the ownership of a key - * - the keyring owned by the changer - * - if the uid or gid is -1, then that parameter is not changed - * - implements keyctl(KEYCTL_CHOWN) + * Change the ownership of a key + * + * The key must grant the caller Setattr permission for this to work, though + * the key need not be fully instantiated yet. For the UID to be changed, or + * for the GID to be changed to a group the caller is not a member of, the + * caller must have sysadmin capability. If either uid or gid is -1 then that + * attribute is not changed. + * + * If the UID is to be changed, the new user must have sufficient quota to + * accept the key. The quota deduction will be removed from the old user to + * the new user should the attribute be changed. + * + * If successful, 0 will be returned. */ -long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid) +long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group) { struct key_user *newowner, *zapowner = NULL; struct key *key; key_ref_t key_ref; long ret; + kuid_t uid; + kgid_t gid; + + uid = make_kuid(current_user_ns(), user); + gid = make_kgid(current_user_ns(), group); + ret = -EINVAL; + if ((user != (uid_t) -1) && !uid_valid(uid)) + goto error; + if ((group != (gid_t) -1) && !gid_valid(gid)) + goto error; ret = 0; - if (uid == (uid_t) -1 && gid == (gid_t) -1) + if (user == (uid_t) -1 && group == (gid_t) -1) goto error; key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, - KEY_SETATTR); + KEY_NEED_SETATTR); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error; @@ -724,27 +813,27 @@ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid) if (!capable(CAP_SYS_ADMIN)) { /* only the sysadmin can chown a key to some other UID */ - if (uid != (uid_t) -1 && key->uid != uid) + if (user != (uid_t) -1 && !uid_eq(key->uid, uid)) goto error_put; /* only the sysadmin can set the key's GID to a group other * than one of those that the current process subscribes to */ - if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid)) + if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid)) goto error_put; } /* change the UID */ - if (uid != (uid_t) -1 && uid != key->uid) { + if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) { ret = -ENOMEM; - newowner = key_user_lookup(uid, current_user_ns()); + newowner = key_user_lookup(uid); if (!newowner) goto error_put; /* transfer the quota burden to the new user */ if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { - unsigned maxkeys = (uid == 0) ? + unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ? key_quota_root_maxkeys : key_quota_maxkeys; - unsigned maxbytes = (uid == 0) ? + unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ? key_quota_root_maxbytes : key_quota_maxbytes; spin_lock(&newowner->lock); @@ -778,7 +867,7 @@ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid) } /* change the GID */ - if (gid != (gid_t) -1) + if (group != (gid_t) -1) key->gid = gid; ret = 0; @@ -796,14 +885,14 @@ quota_overrun: zapowner = newowner; ret = -EDQUOT; goto error_put; +} -} /* end keyctl_chown_key() */ - -/*****************************************************************************/ /* - * change the permission mask on a key - * - the keyring owned by the changer - * - implements keyctl(KEYCTL_SETPERM) + * Change the permission mask on a key. + * + * The key must grant the caller Setattr permission for this to work, though + * the key need not be fully instantiated yet. If the caller does not have + * sysadmin capability, it may only change the permission on keys that it owns. */ long keyctl_setperm_key(key_serial_t id, key_perm_t perm) { @@ -816,7 +905,7 @@ long keyctl_setperm_key(key_serial_t id, key_perm_t perm) goto error; key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, - KEY_SETATTR); + KEY_NEED_SETATTR); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error; @@ -829,7 +918,7 @@ long keyctl_setperm_key(key_serial_t id, key_perm_t perm) down_write(&key->sem); /* if we're not the sysadmin, we can only change a key that we own */ - if (capable(CAP_SYS_ADMIN) || key->uid == current_fsuid()) { + if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) { key->perm = perm; ret = 0; } @@ -838,11 +927,11 @@ long keyctl_setperm_key(key_serial_t id, key_perm_t perm) key_put(key); error: return ret; - -} /* end keyctl_setperm_key() */ +} /* - * get the destination keyring for instantiation + * Get the destination keyring for instantiation and check that the caller has + * Write permission on it. */ static long get_instantiation_keyring(key_serial_t ringid, struct request_key_auth *rka, @@ -858,7 +947,7 @@ static long get_instantiation_keyring(key_serial_t ringid, /* if a specific keyring is nominated by ID, then use that */ if (ringid > 0) { - dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); + dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE); if (IS_ERR(dkref)) return PTR_ERR(dkref); *_dest_keyring = key_ref_to_ptr(dkref); @@ -879,7 +968,7 @@ static long get_instantiation_keyring(key_serial_t ringid, } /* - * change the request_key authorisation key on the current process + * Change the request_key authorisation key on the current process. */ static int keyctl_change_reqkey_auth(struct key *key) { @@ -895,15 +984,35 @@ static int keyctl_change_reqkey_auth(struct key *key) return commit_creds(new); } -/*****************************************************************************/ /* - * instantiate the key with the specified payload, and, if one is given, link - * the key into the keyring + * Copy the iovec data from userspace */ -long keyctl_instantiate_key(key_serial_t id, - const void __user *_payload, - size_t plen, - key_serial_t ringid) +static long copy_from_user_iovec(void *buffer, const struct iovec *iov, + unsigned ioc) +{ + for (; ioc > 0; ioc--) { + if (copy_from_user(buffer, iov->iov_base, iov->iov_len) != 0) + return -EFAULT; + buffer += iov->iov_len; + iov++; + } + return 0; +} + +/* + * Instantiate a key with the specified payload and link the key into the + * destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * If successful, 0 will be returned. + */ +long keyctl_instantiate_key_common(key_serial_t id, + const struct iovec *payload_iov, + unsigned ioc, + size_t plen, + key_serial_t ringid) { const struct cred *cred = current_cred(); struct request_key_auth *rka; @@ -932,7 +1041,7 @@ long keyctl_instantiate_key(key_serial_t id, /* pull the payload in if one was supplied */ payload = NULL; - if (_payload) { + if (payload_iov) { ret = -ENOMEM; payload = kmalloc(plen, GFP_KERNEL); if (!payload) { @@ -944,8 +1053,8 @@ long keyctl_instantiate_key(key_serial_t id, goto error; } - ret = -EFAULT; - if (copy_from_user(payload, _payload, plen) != 0) + ret = copy_from_user_iovec(payload, payload_iov, ioc); + if (ret < 0) goto error2; } @@ -973,22 +1082,127 @@ error2: vfree(payload); error: return ret; +} + +/* + * Instantiate a key with the specified payload and link the key into the + * destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * If successful, 0 will be returned. + */ +long keyctl_instantiate_key(key_serial_t id, + const void __user *_payload, + size_t plen, + key_serial_t ringid) +{ + if (_payload && plen) { + struct iovec iov[1] = { + [0].iov_base = (void __user *)_payload, + [0].iov_len = plen + }; + + return keyctl_instantiate_key_common(id, iov, 1, plen, ringid); + } + + return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid); +} + +/* + * Instantiate a key with the specified multipart payload and link the key into + * the destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * If successful, 0 will be returned. + */ +long keyctl_instantiate_key_iov(key_serial_t id, + const struct iovec __user *_payload_iov, + unsigned ioc, + key_serial_t ringid) +{ + struct iovec iovstack[UIO_FASTIOV], *iov = iovstack; + long ret; + + if (!_payload_iov || !ioc) + goto no_payload; + + ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc, + ARRAY_SIZE(iovstack), iovstack, &iov); + if (ret < 0) + goto err; + if (ret == 0) + goto no_payload_free; + + ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid); +err: + if (iov != iovstack) + kfree(iov); + return ret; -} /* end keyctl_instantiate_key() */ +no_payload_free: + if (iov != iovstack) + kfree(iov); +no_payload: + return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid); +} -/*****************************************************************************/ /* - * negatively instantiate the key with the given timeout (in seconds), and, if - * one is given, link the key into the keyring + * Negatively instantiate the key with the given timeout (in seconds) and link + * the key into the destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * The key and any links to the key will be automatically garbage collected + * after the timeout expires. + * + * Negative keys are used to rate limit repeated request_key() calls by causing + * them to return -ENOKEY until the negative key expires. + * + * If successful, 0 will be returned. */ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) { + return keyctl_reject_key(id, timeout, ENOKEY, ringid); +} + +/* + * Negatively instantiate the key with the given timeout (in seconds) and error + * code and link the key into the destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * The key and any links to the key will be automatically garbage collected + * after the timeout expires. + * + * Negative keys are used to rate limit repeated request_key() calls by causing + * them to return the specified error code until the negative key expires. + * + * If successful, 0 will be returned. + */ +long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error, + key_serial_t ringid) +{ const struct cred *cred = current_cred(); struct request_key_auth *rka; struct key *instkey, *dest_keyring; long ret; - kenter("%d,%u,%d", id, timeout, ringid); + kenter("%d,%u,%u,%d", id, timeout, error, ringid); + + /* must be a valid error code and mustn't be a kernel special */ + if (error <= 0 || + error >= MAX_ERRNO || + error == ERESTARTSYS || + error == ERESTARTNOINTR || + error == ERESTARTNOHAND || + error == ERESTART_RESTARTBLOCK) + return -EINVAL; /* the appropriate instantiation authorisation key must have been * assumed before calling this */ @@ -1008,7 +1222,7 @@ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) goto error; /* instantiate the key and link it into a keyring */ - ret = key_negate_and_link(rka->target_key, timeout, + ret = key_reject_and_link(rka->target_key, timeout, error, dest_keyring, instkey); key_put(dest_keyring); @@ -1020,13 +1234,14 @@ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) error: return ret; +} -} /* end keyctl_negate_key() */ - -/*****************************************************************************/ /* - * set the default keyring in which request_key() will cache keys - * - return the old setting + * Read or set the default keyring in which request_key() will cache keys and + * return the old setting. + * + * If a process keyring is specified then this will be created if it doesn't + * yet exist. The old setting will be returned if successful. */ long keyctl_set_reqkey_keyring(int reqkey_defl) { @@ -1079,23 +1294,28 @@ set: error: abort_creds(new); return ret; +} -} /* end keyctl_set_reqkey_keyring() */ - -/*****************************************************************************/ /* - * set or clear the timeout for a key + * Set or clear the timeout on a key. + * + * Either the key must grant the caller Setattr permission or else the caller + * must hold an instantiation authorisation token for the key. + * + * The timeout is either 0 to clear the timeout, or a number of seconds from + * the current time. The key and any links to the key will be automatically + * garbage collected after the timeout expires. + * + * If successful, 0 is returned. */ long keyctl_set_timeout(key_serial_t id, unsigned timeout) { - struct timespec now; struct key *key, *instkey; key_ref_t key_ref; - time_t expiry; long ret; key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, - KEY_SETATTR); + KEY_NEED_SETATTR); if (IS_ERR(key_ref)) { /* setting the timeout on a key under construction is permitted * if we have the authorisation token handy */ @@ -1117,31 +1337,30 @@ long keyctl_set_timeout(key_serial_t id, unsigned timeout) okay: key = key_ref_to_ptr(key_ref); - - /* make the changes with the locks held to prevent races */ - down_write(&key->sem); - - expiry = 0; - if (timeout > 0) { - now = current_kernel_time(); - expiry = now.tv_sec + timeout; - } - - key->expiry = expiry; - key_schedule_gc(key->expiry + key_gc_delay); - - up_write(&key->sem); + key_set_timeout(key, timeout); key_put(key); ret = 0; error: return ret; +} -} /* end keyctl_set_timeout() */ - -/*****************************************************************************/ /* - * assume the authority to instantiate the specified key + * Assume (or clear) the authority to instantiate the specified key. + * + * This sets the authoritative token currently in force for key instantiation. + * This must be done for a key to be instantiated. It has the effect of making + * available all the keys from the caller of the request_key() that created a + * key to request_key() calls made by the caller of this function. + * + * The caller must have the instantiation key in their process keyrings with a + * Search permission grant available to the caller. + * + * If the ID given is 0, then the setting will be cleared and 0 returned. + * + * If the ID given has a matching an authorisation key, then that key will be + * set and its ID will be returned. The authorisation key can be read to get + * the callout information passed to request_key(). */ long keyctl_assume_authority(key_serial_t id) { @@ -1178,16 +1397,17 @@ long keyctl_assume_authority(key_serial_t id) ret = authkey->serial; error: return ret; - -} /* end keyctl_assume_authority() */ +} /* - * get the security label of a key - * - the key must grant us view permission - * - if there's a buffer, we place up to buflen bytes of data into it - * - unless there's an error, we return the amount of information available, - * irrespective of how much we may have copied (including the terminal NUL) - * - implements keyctl(KEYCTL_GET_SECURITY) + * Get a key's the LSM security label. + * + * The key must grant the caller View permission for this to work. + * + * If there's a buffer, then up to buflen bytes of data will be placed into it. + * + * If successful, the amount of information available will be returned, + * irrespective of how much was copied (including the terminal NUL). */ long keyctl_get_security(key_serial_t keyid, char __user *buffer, @@ -1198,7 +1418,7 @@ long keyctl_get_security(key_serial_t keyid, char *context; long ret; - key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW); + key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW); if (IS_ERR(key_ref)) { if (PTR_ERR(key_ref) != -EACCES) return PTR_ERR(key_ref); @@ -1242,115 +1462,110 @@ long keyctl_get_security(key_serial_t keyid, } /* - * attempt to install the calling process's session keyring on the process's - * parent process - * - the keyring must exist and must grant us LINK permission - * - implements keyctl(KEYCTL_SESSION_TO_PARENT) + * Attempt to install the calling process's session keyring on the process's + * parent process. + * + * The keyring must exist and must grant the caller LINK permission, and the + * parent process must be single-threaded and must have the same effective + * ownership as this process and mustn't be SUID/SGID. + * + * The keyring will be emplaced on the parent when it next resumes userspace. + * + * If successful, 0 will be returned. */ long keyctl_session_to_parent(void) { -#ifdef TIF_NOTIFY_RESUME struct task_struct *me, *parent; const struct cred *mycred, *pcred; - struct cred *cred, *oldcred; + struct callback_head *newwork, *oldwork; key_ref_t keyring_r; + struct cred *cred; int ret; - keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK); + keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK); if (IS_ERR(keyring_r)) return PTR_ERR(keyring_r); + ret = -ENOMEM; + /* our parent is going to need a new cred struct, a new tgcred struct * and new security data, so we allocate them here to prevent ENOMEM in * our parent */ - ret = -ENOMEM; cred = cred_alloc_blank(); if (!cred) goto error_keyring; + newwork = &cred->rcu; - cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r); + cred->session_keyring = key_ref_to_ptr(keyring_r); keyring_r = NULL; + init_task_work(newwork, key_change_session_keyring); me = current; rcu_read_lock(); write_lock_irq(&tasklist_lock); - parent = me->real_parent; ret = -EPERM; + oldwork = NULL; + parent = me->real_parent; /* the parent mustn't be init and mustn't be a kernel thread */ if (parent->pid <= 1 || !parent->mm) - goto not_permitted; + goto unlock; /* the parent must be single threaded */ if (!thread_group_empty(parent)) - goto not_permitted; + goto unlock; /* the parent and the child must have different session keyrings or * there's no point */ mycred = current_cred(); pcred = __task_cred(parent); if (mycred == pcred || - mycred->tgcred->session_keyring == pcred->tgcred->session_keyring) - goto already_same; + mycred->session_keyring == pcred->session_keyring) { + ret = 0; + goto unlock; + } /* the parent must have the same effective ownership and mustn't be * SUID/SGID */ - if (pcred->uid != mycred->euid || - pcred->euid != mycred->euid || - pcred->suid != mycred->euid || - pcred->gid != mycred->egid || - pcred->egid != mycred->egid || - pcred->sgid != mycred->egid) - goto not_permitted; + if (!uid_eq(pcred->uid, mycred->euid) || + !uid_eq(pcred->euid, mycred->euid) || + !uid_eq(pcred->suid, mycred->euid) || + !gid_eq(pcred->gid, mycred->egid) || + !gid_eq(pcred->egid, mycred->egid) || + !gid_eq(pcred->sgid, mycred->egid)) + goto unlock; /* the keyrings must have the same UID */ - if ((pcred->tgcred->session_keyring && - pcred->tgcred->session_keyring->uid != mycred->euid) || - mycred->tgcred->session_keyring->uid != mycred->euid) - goto not_permitted; + if ((pcred->session_keyring && + !uid_eq(pcred->session_keyring->uid, mycred->euid)) || + !uid_eq(mycred->session_keyring->uid, mycred->euid)) + goto unlock; - /* if there's an already pending keyring replacement, then we replace - * that */ - oldcred = parent->replacement_session_keyring; + /* cancel an already pending keyring replacement */ + oldwork = task_work_cancel(parent, key_change_session_keyring); /* the replacement session keyring is applied just prior to userspace * restarting */ - parent->replacement_session_keyring = cred; - cred = NULL; - set_ti_thread_flag(task_thread_info(parent), TIF_NOTIFY_RESUME); - - write_unlock_irq(&tasklist_lock); - rcu_read_unlock(); - if (oldcred) - put_cred(oldcred); - return 0; - -already_same: - ret = 0; -not_permitted: + ret = task_work_add(parent, newwork, true); + if (!ret) + newwork = NULL; +unlock: write_unlock_irq(&tasklist_lock); rcu_read_unlock(); - put_cred(cred); + if (oldwork) + put_cred(container_of(oldwork, struct cred, rcu)); + if (newwork) + put_cred(cred); return ret; error_keyring: key_ref_put(keyring_r); return ret; - -#else /* !TIF_NOTIFY_RESUME */ - /* - * To be removed when TIF_NOTIFY_RESUME has been implemented on - * m68k/xtensa - */ -#warning TIF_NOTIFY_RESUME not implemented - return -EOPNOTSUPP; -#endif /* !TIF_NOTIFY_RESUME */ } -/*****************************************************************************/ /* - * the key control system call + * The key control system call */ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, unsigned long, arg4, unsigned long, arg5) @@ -1436,8 +1651,26 @@ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, case KEYCTL_SESSION_TO_PARENT: return keyctl_session_to_parent(); + case KEYCTL_REJECT: + return keyctl_reject_key((key_serial_t) arg2, + (unsigned) arg3, + (unsigned) arg4, + (key_serial_t) arg5); + + case KEYCTL_INSTANTIATE_IOV: + return keyctl_instantiate_key_iov( + (key_serial_t) arg2, + (const struct iovec __user *) arg3, + (unsigned) arg4, + (key_serial_t) arg5); + + 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; } - -} /* end sys_keyctl() */ +} |