target/linux/brcm2708/patches-4.4/0222-net-fix-bridge-multicast-packet-checksum-validation.patch

   1 From 966e306c7690f118bedf2f5de94e22e487bd39ec Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Linus=20L=C3=BCssing?= <linus.luessing@c0d3.blue>
   3 Date: Wed, 24 Feb 2016 04:21:42 +0100
   4 Subject: [PATCH 222/232] net: fix bridge multicast packet checksum validation
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 We need to update the skb->csum after pulling the skb, otherwise
  10 an unnecessary checksum (re)computation can ocure for IGMP/MLD packets
  11 in the bridge code. Additionally this fixes the following splats for
  12 network devices / bridge ports with support for and enabled RX checksum
  13 offloading:
  14
  15 [...]
  16 [   43.986968] eth0: hw csum failure
  17 [   43.990344] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.4.0 #2
  18 [   43.996193] Hardware name: BCM2709
  19 [   43.999647] [<800204e0>] (unwind_backtrace) from [<8001cf14>] (show_stack+0x10/0x14)
  20 [   44.007432] [<8001cf14>] (show_stack) from [<801ab614>] (dump_stack+0x80/0x90)
  21 [   44.014695] [<801ab614>] (dump_stack) from [<802e4548>] (__skb_checksum_complete+0x6c/0xac)
  22 [   44.023090] [<802e4548>] (__skb_checksum_complete) from [<803a055c>] (ipv6_mc_validate_checksum+0x104/0x178)
  23 [   44.032959] [<803a055c>] (ipv6_mc_validate_checksum) from [<802e111c>] (skb_checksum_trimmed+0x130/0x188)
  24 [   44.042565] [<802e111c>] (skb_checksum_trimmed) from [<803a06e8>] (ipv6_mc_check_mld+0x118/0x338)
  25 [   44.051501] [<803a06e8>] (ipv6_mc_check_mld) from [<803b2c98>] (br_multicast_rcv+0x5dc/0xd00)
  26 [   44.060077] [<803b2c98>] (br_multicast_rcv) from [<803aa510>] (br_handle_frame_finish+0xac/0x51c)
  27 [...]
  28
  29 Fixes: 9afd85c9e455 ("net: Export IGMP/MLD message validation code")
  30 Reported-by: Álvaro Fernández Rojas <noltari@gmail.com>
  31 Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
  32 Signed-off-by: David S. Miller <davem@davemloft.net>
  33 ---
  34  net/core/skbuff.c | 22 ++++++++++++++++++++--
  35  1 file changed, 20 insertions(+), 2 deletions(-)
  36
  37 --- a/net/core/skbuff.c
  38 +++ b/net/core/skbuff.c
  39 @@ -2965,6 +2965,24 @@ int skb_append_pagefrags(struct sk_buff
  40  EXPORT_SYMBOL_GPL(skb_append_pagefrags);
  41
  42  /**
  43 + *     skb_push_rcsum - push skb and update receive checksum
  44 + *     @skb: buffer to update
  45 + *     @len: length of data pulled
  46 + *
  47 + *     This function performs an skb_push on the packet and updates
  48 + *     the CHECKSUM_COMPLETE checksum.  It should be used on
  49 + *     receive path processing instead of skb_push unless you know
  50 + *     that the checksum difference is zero (e.g., a valid IP header)
  51 + *     or you are setting ip_summed to CHECKSUM_NONE.
  52 + */
  53 +static unsigned char *skb_push_rcsum(struct sk_buff *skb, unsigned len)
  54 +{
  55 +       skb_push(skb, len);
  56 +       skb_postpush_rcsum(skb, skb->data, len);
  57 +       return skb->data;
  58 +}
  59 +
  60 +/**
  61   *     skb_pull_rcsum - pull skb and update receive checksum
  62   *     @skb: buffer to update
  63   *     @len: length of data pulled
  64 @@ -4101,9 +4119,9 @@ struct sk_buff *skb_checksum_trimmed(str
  65         if (!pskb_may_pull(skb_chk, offset))
  66                 goto err;
  67
  68 -       __skb_pull(skb_chk, offset);
  69 +       skb_pull_rcsum(skb_chk, offset);
  70         ret = skb_chkf(skb_chk);
  71 -       __skb_push(skb_chk, offset);
  72 +       skb_push_rcsum(skb_chk, offset);
  73
  74         if (ret)
  75                 goto err;