batman-adv/patches/0012-batman-adv-Fix-ICMP-RR-ethernet-access-after-skb_lin.patch

   1 From: Sven Eckelmann <sven@narfation.org>
   2 Date: Sun, 29 May 2016 21:25:52 +0200
   3 Subject: [PATCH] batman-adv: Fix ICMP RR ethernet access after skb_linearize
   4
   5 The skb_linearize may reallocate the skb. This makes the calculated pointer
   6 for ethhdr invalid. But it the pointer is used later to fill in the RR
   7 field of the batadv_icmp_packet_rr packet.
   8
   9 Instead re-evaluate eth_hdr after the skb_linearize+skb_cow to fix the
  10 pointer and avoid the invalid read.
  11
  12 Fixes: bb69cb678d37 ("batman-adv: generalize batman-adv icmp packet handling")
  13 Signed-off-by: Sven Eckelmann <sven@narfation.org>
  14
  15 Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/f6c80c29ef4e8b45b715976107b7ae06fc0be3a0
  16 ---
  17  net/batman-adv/routing.c | 1 +
  18  1 file changed, 1 insertion(+)
  19
  20 diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
  21 index 0c0c30e..27e07dd 100644
  22 --- a/net/batman-adv/routing.c
  23 +++ b/net/batman-adv/routing.c
  24 @@ -374,6 +374,7 @@ int batadv_recv_icmp_packet(struct sk_buff *skb,
  25                 if (skb_cow(skb, ETH_HLEN) < 0)
  26                         goto out;
  27
  28 +               ethhdr = eth_hdr(skb);
  29                 icmph = (struct batadv_icmp_header *)skb->data;
  30                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
  31                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)