lkml.org 
[lkml]   [2013]   [Nov]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 3.5 36/78] net: flow_dissector: fail on evil iph->ihl
    Date
    3.5.7.26 -stable review patch.  If anyone has any objections, please let me know.

    ------------------

    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>
    Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
    ---
    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 2774788..200707c 100644
    --- 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))
    --
    1.8.3.2


    \
     
     \ /
      Last update: 2013-11-25 14:41    [W:4.086 / U:0.020 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site