inet: frags: fix defragmented packet's IP header for af_packet

[ 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 <edjee@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jerry Chu <hkchu@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 4c1884fed54862149dcdf072032c5b82933fafe2..4d98a6b80b0437fcda2c9235850405097cd78396 100644 (file)
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -356,7 +356,7 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
        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, struct sk_buff *skb)
                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, struct sk_buff *prev,
        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;