Smack: Fix IPv6 handling of 0 secmark

Handle the case where the skb for an IPv6 packet contains
a 0 in the secmark for a packet generated locally. This
can only happen for system packets, so allow the access.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index bd45c9139d34..b9abcdb36a73 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3907,6 +3907,8 @@ access_check:
 #ifdef SMACK_IPV6_SECMARK_LABELING
                 if (skb && skb->secmark != 0)
                         skp = smack_from_secid(skb->secmark);
+                else if (smk_ipv6_localhost(&sadd))
+                        break;
                 else
                         skp = smack_ipv6host_label(&sadd);
                 if (skp == NULL)