CRED: Allow put_cred() to cope with a NULL groups list

put_cred() will oops if given a NULL groups list, but that is now possible with
the existence of cred_alloc_blank(), as used in keyctl_session_to_parent().

Added in commit:

	commit ee18d64c1f632043a02e6f5ba5e045bb26a5465f
	Author: David Howells <dhowells@redhat.com>
	Date:   Wed Sep 2 09:14:21 2009 +0100
	KEYS: Add a keyctl to install a process's session keyring on its parent [try #6]

Reported-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/kernel/cred.c b/kernel/cred.c
index 006fcab009d..d7f7a01082e 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -147,7 +147,8 @@ static void put_cred_rcu(struct rcu_head *rcu)
         key_put(cred->thread_keyring);
         key_put(cred->request_key_auth);
         release_tgcred(cred);
-        put_group_info(cred->group_info);
+        if (cred->group_info)
+                put_group_info(cred->group_info);
         free_uid(cred->user);
         kmem_cache_free(cred_jar, cred);
 }