net: flow_dissector: fix thoff for IPPROTO_AH

[ Upstream commit b86783587b3d1d552326d955acee37eac48800f1 ]

In commit 8ed781668dd49 ("flow_keys: include thoff into flow_keys for
later usage"), we missed that existing code was using nhoff as a
temporary variable that could not always contain transport header
offset.

This is not a problem for TCP/UDP because port offset (@poff)
is 0 for these protocols.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Nikolay Aleksandrov <nikolay@redhat.com>
Acked-by: Nikolay Aleksandrov <nikolay@redhat.com>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index a225089..2774788 100644 (file)
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -133,8 +133,8 @@ ipv6:
        if (poff >= 0) {
                __be32 *ports, _ports;
 
-               nhoff += poff;
-               ports = skb_header_pointer(skb, nhoff, sizeof(_ports), &_ports);
+               ports = skb_header_pointer(skb, nhoff + poff,
+                                          sizeof(_ports), &_ports);
                if (ports)
                        flow->ports = *ports;
        }