4.15-stable review patch. If anyone has any objections, please let me know.
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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;