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

netfilter: ipv6: fix use-after-free Write in nf_nat_ipv6_manip_pkt

to the 3.18-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: netfilter-ipv6-fix-use-after-free-write-in-nf_nat_ipv6_manip_pkt.patch and it can be found in the queue-3.18 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 b078556aecd791b0e5cb3a59f4c3a14273b52121 Mon Sep 17 00:00:00 2001

From: Florian Westphal fw@strlen.de Date: Mon, 19 Feb 2018 08:10:17 +0100 Subject: netfilter: ipv6: fix use-after-free Write in nf_nat_ipv6_manip_pkt

From: Florian Westphal fw@strlen.de

commit b078556aecd791b0e5cb3a59f4c3a14273b52121 upstream.

l4proto->manip_pkt() can cause reallocation of skb head so pointer to the ipv6 header must be reloaded.

Reported-and-tested-by: syzbot+10005f4292fc9cc89de7@syzkaller.appspotmail.com Fixes: 58a317f1061c89 ("netfilter: ipv6: add IPv6 NAT support") Signed-off-by: Florian Westphal fw@strlen.de Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- net/ipv6/netfilter/nf_nat_l3proto_ipv6.c | 4 ++++ 1 file changed, 4 insertions(+)

--- a/net/ipv6/netfilter/nf_nat_l3proto_ipv6.c +++ b/net/ipv6/netfilter/nf_nat_l3proto_ipv6.c @@ -99,6 +99,10 @@ static bool nf_nat_ipv6_manip_pkt(struct !l4proto->manip_pkt(skb, &nf_nat_l3proto_ipv6, iphdroff, hdroff, target, maniptype)) return false; + + /* must reload, offset might have changed */ + ipv6h = (void *)skb->data + iphdroff; + manip_addr: if (maniptype == NF_NAT_MANIP_SRC) ipv6h->saddr = target->src.u3.in6;

Patches currently in stable-queue which might be from fw@strlen.de are

queue-3.18/netfilter-ipv6-fix-use-after-free-write-in-nf_nat_ipv6_manip_pkt.patch queue-3.18/netfilter-ebtables-config_compat-don-t-trust-userland-offsets.patch queue-3.18/netfilter-bridge-ebt_among-add-missing-match-size-checks.patch