Merge tag 'keys-misc-20190619' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull misc keyring updates from David Howells:
 "These are some miscellaneous keyrings fixes and improvements:

   - Fix a bunch of warnings from sparse, including missing RCU bits and
     kdoc-function argument mismatches

   - Implement a keyctl to allow a key to be moved from one keyring to
     another, with the option of prohibiting key replacement in the
     destination keyring.

   - Grant Link permission to possessors of request_key_auth tokens so
     that upcall servicing daemons can more easily arrange things such
     that only the necessary auth key is passed to the actual service
     program, and not all the auth keys a daemon might possesss.

   - Improvement in lookup_user_key().

   - Implement a keyctl to allow keyrings subsystem capabilities to be
     queried.

  The keyutils next branch has commits to make available, document and
  test the move-key and capabilities code:

        https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git/log

  They're currently on the 'next' branch"

* tag 'keys-misc-20190619' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  keys: Add capability-checking keyctl function
  keys: Reuse keyring_index_key::desc_len in lookup_user_key()
  keys: Grant Link permission to possessers of request_key auth keys
  keys: Add a keyctl to move a key between keyrings
  keys: Hoist locking out of __key_link_begin()
  keys: Break bits out of key_unlink()
  keys: Change keyring_serialise_link_sem to a mutex
  keys: sparse: Fix kdoc mismatches
  keys: sparse: Fix incorrect RCU accesses
  keys: sparse: Fix key_fs[ug]id_changed()

1 files changed, 7 insertions, 2 deletions

diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 8ae3b7b18801..fcef7e26b94b 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -20,7 +20,7 @@
 
 /**
  * complete_request_key - Complete the construction of a key.
- * @auth_key: The authorisation key.
+ * @authkey: The authorisation key.
  * @error: The success or failute of the construction.
  *
  * Complete the attempt to construct a key.  The key will be negated
@@ -339,7 +339,7 @@ static int construct_alloc_key(struct keyring_search_context *ctx,
 			       struct key_user *user,
 			       struct key **_key)
 {
-	struct assoc_array_edit *edit;
+	struct assoc_array_edit *edit = NULL;
 	struct key *key;
 	key_perm_t perm;
 	key_ref_t key_ref;
@@ -368,6 +368,9 @@ static int construct_alloc_key(struct keyring_search_context *ctx,
 	set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
 
 	if (dest_keyring) {
+		ret = __key_link_lock(dest_keyring, &ctx->index_key);
+		if (ret < 0)
+			goto link_lock_failed;
 		ret = __key_link_begin(dest_keyring, &ctx->index_key, &edit);
 		if (ret < 0)
 			goto link_prealloc_failed;
@@ -419,6 +422,8 @@ link_check_failed:
 	return ret;
 
 link_prealloc_failed:
+	__key_link_end(dest_keyring, &ctx->index_key, edit);
+link_lock_failed:
 	mutex_unlock(&user->cons_lock);
 	key_put(key);
 	kleave(" = %d [prelink]", ret);