| From | Ben Hutchings <> | Date | Sun, 29 Dec 2013 03:08:44 +0100 | Subject | [PATCH 3.2 180/185] net: flow_dissector: fail on evil iph->ihl |
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3.2.54-rc1 review patch. If anyone has any objections, please let me know.
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From: Jason Wang <jasowang@redhat.com>
commit 6f092343855a71e03b8d209815d8c45bf3a27fcd upstream.
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> [bwh: Backported to 3.2: the affected code is in __skb_get_rxhash()] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- net/core/flow_dissector.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/core/dev.c +++ b/net/core/dev.c @@ -2609,6 +2609,8 @@ ip: goto done; ip = (const struct iphdr *) (skb->data + nhoff); + if (ip->ihl < 5) + goto done; if (ip_is_fragment(ip)) ip_proto = 0; else
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