diff options
| -rw-r--r-- | Documentation/security/keys/core.rst | 21 | ||||
| -rw-r--r-- | include/linux/key.h | 5 | ||||
| -rw-r--r-- | include/uapi/linux/keyctl.h | 3 | ||||
| -rw-r--r-- | security/keys/compat.c | 3 | ||||
| -rw-r--r-- | security/keys/internal.h | 3 | ||||
| -rw-r--r-- | security/keys/keyctl.c | 52 | ||||
| -rw-r--r-- | security/keys/keyring.c | 108 |
7 files changed, 195 insertions, 0 deletions
diff --git a/Documentation/security/keys/core.rst b/Documentation/security/keys/core.rst index 9521c4207f01..823d29bf44f7 100644 --- a/Documentation/security/keys/core.rst +++ b/Documentation/security/keys/core.rst @@ -577,6 +577,27 @@ The keyctl syscall functions are: added. + * Move a key from one keyring to another:: + + long keyctl(KEYCTL_MOVE, + key_serial_t id, + key_serial_t from_ring_id, + key_serial_t to_ring_id, + unsigned int flags); + + Move the key specified by "id" from the keyring specified by + "from_ring_id" to the keyring specified by "to_ring_id". If the two + keyrings are the same, nothing is done. + + "flags" can have KEYCTL_MOVE_EXCL set in it to cause the operation to fail + with EEXIST if a matching key exists in the destination keyring, otherwise + such a key will be replaced. + + A process must have link permission on the key for this function to be + successful and write permission on both keyrings. Any errors that can + occur from KEYCTL_LINK also apply on the destination keyring here. + + * Unlink a key or keyring from another keyring:: long keyctl(KEYCTL_UNLINK, key_serial_t keyring, key_serial_t key); diff --git a/include/linux/key.h b/include/linux/key.h index 1f09aad1c98c..612e1cf84049 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -310,6 +310,11 @@ extern int key_update(key_ref_t key, extern int key_link(struct key *keyring, struct key *key); +extern int key_move(struct key *key, + struct key *from_keyring, + struct key *to_keyring, + unsigned int flags); + extern int key_unlink(struct key *keyring, struct key *key); diff --git a/include/uapi/linux/keyctl.h b/include/uapi/linux/keyctl.h index f45ee0f69c0c..fd9fb11b312b 100644 --- a/include/uapi/linux/keyctl.h +++ b/include/uapi/linux/keyctl.h @@ -67,6 +67,7 @@ #define KEYCTL_PKEY_SIGN 27 /* Create a public key signature */ #define KEYCTL_PKEY_VERIFY 28 /* Verify a public key signature */ #define KEYCTL_RESTRICT_KEYRING 29 /* Restrict keys allowed to link to a keyring */ +#define KEYCTL_MOVE 30 /* Move keys between keyrings */ /* keyctl structures */ struct keyctl_dh_params { @@ -112,4 +113,6 @@ struct keyctl_pkey_params { __u32 __spare[7]; }; +#define KEYCTL_MOVE_EXCL 0x00000001 /* Do not displace from the to-keyring */ + #endif /* _LINUX_KEYCTL_H */ diff --git a/security/keys/compat.c b/security/keys/compat.c index 9482df601dc3..b326bc4f84d7 100644 --- a/security/keys/compat.c +++ b/security/keys/compat.c @@ -159,6 +159,9 @@ COMPAT_SYSCALL_DEFINE5(keyctl, u32, option, return keyctl_pkey_verify(compat_ptr(arg2), compat_ptr(arg3), compat_ptr(arg4), compat_ptr(arg5)); + case KEYCTL_MOVE: + return keyctl_keyring_move(arg2, arg3, arg4, arg5); + default: return -EOPNOTSUPP; } diff --git a/security/keys/internal.h b/security/keys/internal.h index 25cdd0cbdc06..b54a58c025ae 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -95,6 +95,8 @@ extern void key_type_put(struct key_type *ktype); extern int __key_link_lock(struct key *keyring, const struct keyring_index_key *index_key); +extern int __key_move_lock(struct key *l_keyring, struct key *u_keyring, + const struct keyring_index_key *index_key); extern int __key_link_begin(struct key *keyring, const struct keyring_index_key *index_key, struct assoc_array_edit **_edit); @@ -217,6 +219,7 @@ extern long keyctl_update_key(key_serial_t, const void __user *, size_t); extern long keyctl_revoke_key(key_serial_t); extern long keyctl_keyring_clear(key_serial_t); extern long keyctl_keyring_link(key_serial_t, key_serial_t); +extern long keyctl_keyring_move(key_serial_t, key_serial_t, key_serial_t, unsigned int); extern long keyctl_keyring_unlink(key_serial_t, key_serial_t); extern long keyctl_describe_key(key_serial_t, char __user *, size_t); extern long keyctl_keyring_search(key_serial_t, const char __user *, diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index 0f947bcbad46..bbfe7d92d41c 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -573,6 +573,52 @@ error: } /* + * Move a link to a key from one keyring to another, displacing any matching + * key from the destination keyring. + * + * The key must grant the caller Link permission and both keyrings must grant + * the caller Write permission. There must also be a link in the from keyring + * to the key. If both keyrings are the same, nothing is done. + * + * If successful, 0 will be returned. + */ +long keyctl_keyring_move(key_serial_t id, key_serial_t from_ringid, + key_serial_t to_ringid, unsigned int flags) +{ + key_ref_t key_ref, from_ref, to_ref; + long ret; + + if (flags & ~KEYCTL_MOVE_EXCL) + return -EINVAL; + + key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK); + if (IS_ERR(key_ref)) + return PTR_ERR(key_ref); + + from_ref = lookup_user_key(from_ringid, 0, KEY_NEED_WRITE); + if (IS_ERR(from_ref)) { + ret = PTR_ERR(from_ref); + goto error2; + } + + to_ref = lookup_user_key(to_ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE); + if (IS_ERR(to_ref)) { + ret = PTR_ERR(to_ref); + goto error3; + } + + ret = key_move(key_ref_to_ptr(key_ref), key_ref_to_ptr(from_ref), + key_ref_to_ptr(to_ref), flags); + + key_ref_put(to_ref); +error3: + key_ref_put(from_ref); +error2: + key_ref_put(key_ref); + return ret; +} + +/* * Return a description of a key to userspace. * * The key must grant the caller View permission for this to work. @@ -1772,6 +1818,12 @@ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, (const void __user *)arg4, (const void __user *)arg5); + case KEYCTL_MOVE: + return keyctl_keyring_move((key_serial_t)arg2, + (key_serial_t)arg3, + (key_serial_t)arg4, + (unsigned int)arg5); + default: return -EOPNOTSUPP; } diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 12acad3db6cf..67066bb58b83 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -1222,6 +1222,40 @@ int __key_link_lock(struct key *keyring, } /* + * Lock keyrings for move (link/unlink combination). + */ +int __key_move_lock(struct key *l_keyring, struct key *u_keyring, + const struct keyring_index_key *index_key) + __acquires(&l_keyring->sem) + __acquires(&u_keyring->sem) + __acquires(&keyring_serialise_link_lock) +{ + if (l_keyring->type != &key_type_keyring || + u_keyring->type != &key_type_keyring) + return -ENOTDIR; + + /* We have to be very careful here to take the keyring locks in the + * right order, lest we open ourselves to deadlocking against another + * move operation. + */ + if (l_keyring < u_keyring) { + down_write(&l_keyring->sem); + down_write_nested(&u_keyring->sem, 1); + } else { + down_write(&u_keyring->sem); + down_write_nested(&l_keyring->sem, 1); + } + + /* Serialise link/link calls to prevent parallel calls causing a cycle + * when linking two keyring in opposite orders. + */ + if (index_key->type == &key_type_keyring) + mutex_lock(&keyring_serialise_link_lock); + + return 0; +} + +/* * Preallocate memory so that a key can be linked into to a keyring. */ int __key_link_begin(struct key *keyring, @@ -1495,6 +1529,80 @@ int key_unlink(struct key *keyring, struct key *key) EXPORT_SYMBOL(key_unlink); /** + * key_move - Move a key from one keyring to another + * @key: The key to move + * @from_keyring: The keyring to remove the link from. + * @to_keyring: The keyring to make the link in. + * @flags: Qualifying flags, such as KEYCTL_MOVE_EXCL. + * + * Make a link in @to_keyring to a key, such that the keyring holds a reference + * on that key and the key can potentially be found by searching that keyring + * whilst simultaneously removing a link to the key from @from_keyring. + * + * This function will write-lock both keyring's semaphores and will consume + * some of the user's key data quota to hold the link on @to_keyring. + * + * Returns 0 if successful, -ENOTDIR if either keyring isn't a keyring, + * -EKEYREVOKED if either keyring has been revoked, -ENFILE if the second + * keyring is full, -EDQUOT if there is insufficient key data quota remaining + * to add another link or -ENOMEM if there's insufficient memory. If + * KEYCTL_MOVE_EXCL is set, then -EEXIST will be returned if there's already a + * matching key in @to_keyring. + * + * It is assumed that the caller has checked that it is permitted for a link to + * be made (the keyring should have Write permission and the key Link + * permission). + */ +int key_move(struct key *key, + struct key *from_keyring, + struct key *to_keyring, + unsigned int flags) +{ + struct assoc_array_edit *from_edit = NULL, *to_edit = NULL; + int ret; + + kenter("%d,%d,%d", key->serial, from_keyring->serial, to_keyring->serial); + + if (from_keyring == to_keyring) + return 0; + + key_check(key); + key_check(from_keyring); + key_check(to_keyring); + + ret = __key_move_lock(from_keyring, to_keyring, &key->index_key); + if (ret < 0) + goto out; + ret = __key_unlink_begin(from_keyring, key, &from_edit); + if (ret < 0) + goto error; + ret = __key_link_begin(to_keyring, &key->index_key, &to_edit); + if (ret < 0) + goto error; + + ret = -EEXIST; + if (to_edit->dead_leaf && (flags & KEYCTL_MOVE_EXCL)) + goto error; + + ret = __key_link_check_restriction(to_keyring, key); + if (ret < 0) + goto error; + ret = __key_link_check_live_key(to_keyring, key); + if (ret < 0) + goto error; + + __key_unlink(from_keyring, key, &from_edit); + __key_link(key, &to_edit); +error: + __key_link_end(to_keyring, &key->index_key, to_edit); + __key_unlink_end(from_keyring, key, from_edit); +out: + kleave(" = %d", ret); + return ret; +} +EXPORT_SYMBOL(key_move); + +/** * keyring_clear - Clear a keyring * @keyring: The keyring to clear. * |