[PATCH] Set cred->user_ns in key_replace_session_keyring

["Serge E. Hallyn" <serge@hallyn.com>]

Since this cred was not created with copy_creds(), it needs to get
initialized.  Otherwise use of syscall(__NR_keyctl, KEYCTL_SESSION_TO_PARENT);
can lead to a NULL deref.  Thanks to Robert for finding this.

Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Reported-by: Robert Święcki <robert@swiecki.net>
Cc: David Howells <dhowells@redhat.com>
---
 security/keys/process_keys.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 6c0480d..92a3a5d 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -847,6 +847,7 @@ void key_replace_session_keyring(void)
 	new-> sgid	= old-> sgid;
 	new->fsgid	= old->fsgid;
 	new->user	= get_uid(old->user);
+	new->user_ns	= new->user->user_ns;
 	new->group_info	= get_group_info(old->group_info);
 
 	new->securebits	= old->securebits;
-- 
1.7.0.4