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From: Jason Wang <jasowang@redhat.com>
Newsgroups: gmane.linux.kernel,gmane.linux.network
Subject: [PATCH net] net: flow_dissector: fail on evil iph->ihl
Date: Fri, 1 Nov 2013 15:01:10 +0800
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Cc: Jason Wang <jasowang@redhat.com>,
Petr Matousek <pmatouse@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Daniel Borkmann <dborkman@redhat.com>
To: davem@davemloft.net, edumazet@google.com, netdev@vger.kernel.org,
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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>
---
This patch is needed for stable.
---
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 8d7d0dd..143b6fd 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -40,7 +40,7 @@ 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))
--
1.8.1.2