batman-adv/patches/0034-batman-adv-Fix-skbuff-rcsum-on-packet-reroute.patch

   1 From: Sven Eckelmann <sven@narfation.org>
   2 Date: Sun, 18 Mar 2018 13:12:01 +0100
   3 Subject: batman-adv: Fix skbuff rcsum on packet reroute
   4
   5 batadv_check_unicast_ttvn may redirect a packet to itself or another
   6 originator. This involves rewriting the ttvn and the destination address in
   7 the batadv unicast header. These field were not yet pulled (with skb rcsum
   8 update) and thus any change to them also requires a change in the receive
   9 checksum.
  10
  11 Reported-by: Matthias Schiffer <mschiffer@universe-factory.net>
  12 Fixes: cea194d90b11 ("batman-adv: improved client announcement mechanism")
  13 Signed-off-by: Sven Eckelmann <sven@narfation.org>
  14
  15 Origin: backport, https://git.open-mesh.org/batman-adv.git/commit/fb91b0ef84738102807e5dd7ec0b3565415aff56
  16
  17 diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
  18 index 8d927931017e53d285d9c64b4b850bb1d0388e11..6a12612463127f501ad6a0df20632f14586075bd 100644
  19 --- a/net/batman-adv/routing.c
  20 +++ b/net/batman-adv/routing.c
  21 @@ -744,6 +744,7 @@ free_skb:
  22  /**
  23   * batadv_reroute_unicast_packet - update the unicast header for re-routing
  24   * @bat_priv: the bat priv with all the soft interface information
  25 + * @skb: unicast packet to process
  26   * @unicast_packet: the unicast header to be updated
  27   * @dst_addr: the payload destination
  28   * @vid: VLAN identifier
  29 @@ -755,7 +756,7 @@ free_skb:
  30   * Return: true if the packet header has been updated, false otherwise
  31   */
  32  static bool
  33 -batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
  34 +batadv_reroute_unicast_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
  35                               struct batadv_unicast_packet *unicast_packet,
  36                               u8 *dst_addr, unsigned short vid)
  37  {
  38 @@ -784,8 +785,10 @@ batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
  39         }
  40
  41         /* update the packet header */
  42 +       skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
  43         ether_addr_copy(unicast_packet->dest, orig_addr);
  44         unicast_packet->ttvn = orig_ttvn;
  45 +       skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
  46
  47         ret = true;
  48  out:
  49 @@ -826,7 +829,7 @@ static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
  50          * the packet to
  51          */
  52         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
  53 -               if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
  54 +               if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
  55                                                   ethhdr->h_dest, vid))
  56                         batadv_dbg_ratelimited(BATADV_DBG_TT,
  57                                                bat_priv,
  58 @@ -872,7 +875,7 @@ static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
  59          * destination can possibly be updated and forwarded towards the new
  60          * target host
  61          */
  62 -       if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
  63 +       if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
  64                                           ethhdr->h_dest, vid)) {
  65                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
  66                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
  67 @@ -895,12 +898,14 @@ static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
  68         if (!primary_if)
  69                 return false;
  70
  71 +       /* update the packet header */
  72 +       skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
  73         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
  74 +       unicast_packet->ttvn = curr_ttvn;
  75 +       skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
  76
  77         batadv_hardif_put(primary_if);
  78
  79 -       unicast_packet->ttvn = curr_ttvn;
  80 -
  81         return true;
  82  }
  83