From: Xin Long lucien.xin@gmail.com
commit ed17b8d377eaf6b4a01d46942b4c647378a79bdd upstream.
This waring can be triggered simply by:
# ip xfrm policy update src 192.168.1.1/24 dst 192.168.1.2/24 dir in \ priority 1 mark 0 mask 0x10 #[1] # ip xfrm policy update src 192.168.1.1/24 dst 192.168.1.2/24 dir in \ priority 2 mark 0 mask 0x1 #[2] # ip xfrm policy update src 192.168.1.1/24 dst 192.168.1.2/24 dir in \ priority 2 mark 0 mask 0x10 #[3]
Then dmesg shows:
[ ] WARNING: CPU: 1 PID: 7265 at net/xfrm/xfrm_policy.c:1548 [ ] RIP: 0010:xfrm_policy_insert_list+0x2f2/0x1030 [ ] Call Trace: [ ] xfrm_policy_inexact_insert+0x85/0xe50 [ ] xfrm_policy_insert+0x4ba/0x680 [ ] xfrm_add_policy+0x246/0x4d0 [ ] xfrm_user_rcv_msg+0x331/0x5c0 [ ] netlink_rcv_skb+0x121/0x350 [ ] xfrm_netlink_rcv+0x66/0x80 [ ] netlink_unicast+0x439/0x630 [ ] netlink_sendmsg+0x714/0xbf0 [ ] sock_sendmsg+0xe2/0x110
The issue was introduced by Commit 7cb8a93968e3 ("xfrm: Allow inserting policies with matching mark and different priorities"). After that, the policies [1] and [2] would be able to be added with different priorities.
However, policy [3] will actually match both [1] and [2]. Policy [1] was matched due to the 1st 'return true' in xfrm_policy_mark_match(), and policy [2] was matched due to the 2nd 'return true' in there. It caused WARN_ON() in xfrm_policy_insert_list().
This patch is to fix it by only (the same value and priority) as the same policy in xfrm_policy_mark_match().
Thanks to Yuehaibing, we could make this fix better.
v1->v2: - check policy->mark.v == pol->mark.v only without mask.
Fixes: 7cb8a93968e3 ("xfrm: Allow inserting policies with matching mark and different priorities") Reported-by: Xiumei Mu xmu@redhat.com Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/xfrm/xfrm_policy.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-)
--- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -757,12 +757,7 @@ static void xfrm_policy_requeue(struct x static bool xfrm_policy_mark_match(struct xfrm_policy *policy, struct xfrm_policy *pol) { - u32 mark = policy->mark.v & policy->mark.m; - - if (policy->mark.v == pol->mark.v && policy->mark.m == pol->mark.m) - return true; - - if ((mark & pol->mark.m) == pol->mark.v && + if (policy->mark.v == pol->mark.v && policy->priority == pol->priority) return true;