[PATCH] Smack: Fix IPv6 handling of 0 secmark

[Casey Schaufler]

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 at schaufler-ca.com>
---
 security/smack/smack_lsm.c | 2 ++
 1 file changed, 2 insertions(+)

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 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 #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)
-- 
2.19.1