3.10-stable review patch.  If anyone has any objections, please let me know.

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

From: Edward Hyunkoo Jee <ed...@google.com>

[ Upstream commit 0848f6428ba3a2e42db124d41ac6f548655735bf ]

When ip_frag_queue() computes positions, it assumes that the passed
sk_buff does not contain L2 headers.

However, when PACKET_FANOUT_FLAG_DEFRAG is used, IP reassembly
functions can be called on outgoing packets that contain L2 headers.

Also, IPv4 checksum is not corrected after reassembly.

Fixes: 7736d33f4262 ("packet: Add pre-defragmentation support for ipv4 
fanouts.")
Signed-off-by: Edward Hyunkoo Jee <ed...@google.com>
Signed-off-by: Eric Dumazet <eduma...@google.com>
Cc: Willem de Bruijn <will...@google.com>
Cc: Jerry Chu <hk...@google.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/ipv4/ip_fragment.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -356,7 +356,7 @@ static int ip_frag_queue(struct ipq *qp,
        ihl = ip_hdrlen(skb);
 
        /* Determine the position of this fragment. */
-       end = offset + skb->len - ihl;
+       end = offset + skb->len - skb_network_offset(skb) - ihl;
        err = -EINVAL;
 
        /* Is this the final fragment? */
@@ -386,7 +386,7 @@ static int ip_frag_queue(struct ipq *qp,
                goto err;
 
        err = -ENOMEM;
-       if (pskb_pull(skb, ihl) == NULL)
+       if (!pskb_pull(skb, skb_network_offset(skb) + ihl))
                goto err;
 
        err = pskb_trim_rcsum(skb, end - offset);
@@ -627,6 +627,9 @@ static int ip_frag_reasm(struct ipq *qp,
        iph->frag_off = qp->q.max_size ? htons(IP_DF) : 0;
        iph->tot_len = htons(len);
        iph->tos |= ecn;
+
+       ip_send_check(iph);
+
        IP_INC_STATS_BH(net, IPSTATS_MIB_REASMOKS);
        qp->q.fragments = NULL;
        qp->q.fragments_tail = NULL;


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