package/kernel/mac80211/patches/309-cfg80211-fix-proto-in-ieee80211_data_to_8023-for-fra.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Wed, 29 Jun 2016 10:02:32 +0200
   3 Subject: [PATCH] cfg80211: fix proto in ieee80211_data_to_8023 for frames
   4  without LLC header
   5
   6 The PDU length of incoming LLC frames is set to the total skb payload size
   7 in __ieee80211_data_to_8023() of net/wireless/util.c which incorrectly
   8 includes the length of the IEEE 802.11 header.
   9
  10 The resulting LLC frame header has a too large PDU length, causing the
  11 llc_fixup_skb() function of net/llc/llc_input.c to reject the incoming
  12 skb, effectively breaking STP.
  13
  14 Solve the problem by properly substracting the IEEE 802.11 frame header size
  15 from the PDU length, allowing the LLC processor to pick up the incoming
  16 control messages.
  17
  18 Special thanks to Gerry Rozema for tracking down the regression and proposing
  19 a suitable patch.
  20
  21 Fixes: 2d1c304cb2d5 ("cfg80211: add function for 802.3 conversion with separate output buffer")
  22 Cc: stable@vger.kernel.org
  23 Reported-by: Gerry Rozema <gerryr@rozeware.com>
  24 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  25 ---
  26
  27 --- a/net/wireless/util.c
  28 +++ b/net/wireless/util.c
  29 @@ -509,7 +509,7 @@ static int __ieee80211_data_to_8023(stru
  30                  * replace EtherType */
  31                 hdrlen += ETH_ALEN + 2;
  32         else
  33 -               tmp.h_proto = htons(skb->len);
  34 +               tmp.h_proto = htons(skb->len - hdrlen);
  35
  36         pskb_pull(skb, hdrlen);
  37