From 6f092343855a71e03b8d209815d8c45bf3a27fcd Mon Sep 17 00:00:00 2001 From: Jason Wang <jasowang@redhat.com> Date: Fri, 1 Nov 2013 15:01:10 +0800 Subject: [PATCH] net: flow_dissector: fail on evil iph->ihl We don't validate iph->ihl which may lead a dead loop if we meet a IPIP skb whose iph->ihl is zero. Fix this by failing immediately when iph->ihl is evil (less than 5). This issue were introduced by commit ec5efe7946280d1e84603389a1030ccec0a767ae (rps: support IPIP encapsulation). Cc: Eric Dumazet <edumazet@google.com> Cc: Petr Matousek <pmatouse@redhat.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> --- net/core/flow_dissector.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 8d7d0dd72db21..143b6fdb9647d 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -40,7 +40,7 @@ bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow) struct iphdr _iph; ip: iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph); - if (!iph) + if (!iph || iph->ihl < 5) return false; if (ip_is_fragment(iph)) -- GitLab