From fca443b873af2dbd7e92b23aa40b47d00d880ad2 Mon Sep 17 00:00:00 2001 From: Jason Wang <jasowang@redhat.com> Date: Fri, 1 Nov 2013 15:01:10 +0800 Subject: net: flow_dissector: fail on evil iph->ihl From: Jason Wang <jasowang@redhat.com> [ Upstream commit 6f092343855a71e03b8d209815d8c45bf3a27fcd ] 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). Signed-off-by: Jason Wang <jasowang@redhat.com> 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> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/core/flow_dissector.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -35,7 +35,7 @@ again: 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))
