This is a note to let you know that I've just added the patch titled

xfrm: Fix stack-out-of-bounds read on socket policy lookup.

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: xfrm-fix-stack-out-of-bounds-read-on-socket-policy-lookup.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From ddc47e4404b58f03e98345398fb12d38fe291512 Mon Sep 17 00:00:00 2001

From: Steffen Klassert steffen.klassert@secunet.com Date: Wed, 29 Nov 2017 06:53:55 +0100 Subject: xfrm: Fix stack-out-of-bounds read on socket policy lookup.

From: Steffen Klassert steffen.klassert@secunet.com

commit ddc47e4404b58f03e98345398fb12d38fe291512 upstream.

When we do tunnel or beet mode, we pass saddr and daddr from the template to xfrm_state_find(), this is ok. On transport mode, we pass the addresses from the flowi, assuming that the IP addresses (and address family) don't change during transformation. This assumption is wrong in the IPv4 mapped IPv6 case, packet is IPv4 and template is IPv6.

Fix this by catching address family missmatches of the policy and the flow already before we do the lookup.

Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- net/xfrm/xfrm_policy.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -1257,9 +1257,15 @@ static struct xfrm_policy *xfrm_sk_polic again: pol = rcu_dereference(sk->sk_policy[dir]); if (pol != NULL) { - bool match = xfrm_selector_match(&pol->selector, fl, family); + bool match; int err = 0;

+ if (pol->family != family) { + pol = NULL; + goto out; + } + + match = xfrm_selector_match(&pol->selector, fl, family); if (match) { if ((sk->sk_mark & pol->mark.m) != pol->mark.v) { pol = NULL;

Patches currently in stable-queue which might be from steffen.klassert@secunet.com are

queue-4.9/xfrm-fix-stack-out-of-bounds-read-on-socket-policy-lookup.patch queue-4.9/xfrm-skip-policies-marked-as-dead-while-rehashing.patch queue-4.9/xfrm-check-id-proto-in-validate_tmpl.patch