Don't leak a key reference if request_key() tries to use a revoked keyring

If a request_key() call to allocate and fill out a key attempts to insert the
key structure into a revoked keyring, the key will leak, using memory and part
of the user's key quota until the system reboots. This is from a failure of
construct_alloc_key() to decrement the key's reference count after the attempt
to insert into the requested keyring is rejected.

key_put() needs to be called in the link_prealloc_failed callpath to ensure
the unused key is released.

Signed-off-by: David Jeffery <djeffery@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 0c7aea4dea54..486ef6fa393b 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -414,6 +414,7 @@ link_check_failed:
 
 link_prealloc_failed:
         mutex_unlock(&user->cons_lock);
+        key_put(key);
         kleave(" = %d [prelink]", ret);
         return ret;