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

commit d0709f1e66e8066c4ac6a54620ec116aa41937c0 upstream.

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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index c411f9bb156b205751ae06983e85f547119a245f..5678616cde9db41a6f44701aaba456035ede709c 100644 (file)
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -432,6 +432,7 @@ link_check_failed:
 
 link_prealloc_failed:
        mutex_unlock(&user->cons_lock);
+       key_put(key);
        kleave(" = %d [prelink]", ret);
        return ret;