git.openwrt.org Git - openwrt/staging/mans0n.git/blob

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Fri, 7 Oct 2022 10:54:47 +0200
   3 Subject: [PATCH] wifi: cfg80211: fix ieee80211_data_to_8023_exthdr
   4  handling of small packets
   5
   6 STP topology change notification packets only have a payload of 7 bytes,
   7 so they get dropped due to the skb->len < hdrlen + 8 check.
   8 Fix this by removing skb->len based checks and instead check the return code
   9 on the skb_copy_bits calls.
  10
  11 Fixes: 2d1c304cb2d5 ("cfg80211: add function for 802.3 conversion with separate output buffer")
  12 Reported-by: Chad Monroe <chad.monroe@smartrg.com>
  13 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  14 ---
  15
  16 --- a/net/wireless/util.c
  17 +++ b/net/wireless/util.c
  18 @@ -557,8 +557,6 @@ int ieee80211_data_to_8023_exthdr(struct
  19                 return -1;
  20
  21         hdrlen = ieee80211_hdrlen(hdr->frame_control) + data_offset;
  22 -       if (skb->len < hdrlen + 8)
  23 -               return -1;
  24
  25         /* convert IEEE 802.11 header + possible LLC headers into Ethernet
  26          * header
  27 @@ -572,8 +570,9 @@ int ieee80211_data_to_8023_exthdr(struct
  28         memcpy(tmp.h_dest, ieee80211_get_DA(hdr), ETH_ALEN);
  29         memcpy(tmp.h_source, ieee80211_get_SA(hdr), ETH_ALEN);
  30
  31 -       if (iftype == NL80211_IFTYPE_MESH_POINT)
  32 -               skb_copy_bits(skb, hdrlen, &mesh_flags, 1);
  33 +       if (iftype == NL80211_IFTYPE_MESH_POINT &&
  34 +           skb_copy_bits(skb, hdrlen, &mesh_flags, 1) < 0)
  35 +               return -1;
  36
  37         mesh_flags &= MESH_FLAGS_AE;
  38
  39 @@ -593,11 +592,12 @@ int ieee80211_data_to_8023_exthdr(struct
  40                 if (iftype == NL80211_IFTYPE_MESH_POINT) {
  41                         if (mesh_flags == MESH_FLAGS_AE_A4)
  42                                 return -1;
  43 -                       if (mesh_flags == MESH_FLAGS_AE_A5_A6) {
  44 -                               skb_copy_bits(skb, hdrlen +
  45 -                                       offsetof(struct ieee80211s_hdr, eaddr1),
  46 -                                       tmp.h_dest, 2 * ETH_ALEN);
  47 -                       }
  48 +                       if (mesh_flags == MESH_FLAGS_AE_A5_A6 &&
  49 +                           skb_copy_bits(skb, hdrlen +
  50 +                                         offsetof(struct ieee80211s_hdr, eaddr1),
  51 +                                         tmp.h_dest, 2 * ETH_ALEN) < 0)
  52 +                               return -1;
  53 +
  54                         hdrlen += __ieee80211_get_mesh_hdrlen(mesh_flags);
  55                 }
  56                 break;
  57 @@ -611,10 +611,11 @@ int ieee80211_data_to_8023_exthdr(struct
  58                 if (iftype == NL80211_IFTYPE_MESH_POINT) {
  59                         if (mesh_flags == MESH_FLAGS_AE_A5_A6)
  60                                 return -1;
  61 -                       if (mesh_flags == MESH_FLAGS_AE_A4)
  62 -                               skb_copy_bits(skb, hdrlen +
  63 -                                       offsetof(struct ieee80211s_hdr, eaddr1),
  64 -                                       tmp.h_source, ETH_ALEN);
  65 +                       if (mesh_flags == MESH_FLAGS_AE_A4 &&
  66 +                           skb_copy_bits(skb, hdrlen +
  67 +                                         offsetof(struct ieee80211s_hdr, eaddr1),
  68 +                                         tmp.h_source, ETH_ALEN) < 0)
  69 +                               return -1;
  70                         hdrlen += __ieee80211_get_mesh_hdrlen(mesh_flags);
  71                 }
  72                 break;
  73 @@ -626,18 +627,18 @@ int ieee80211_data_to_8023_exthdr(struct
  74                 break;
  75         }
  76
  77 -       skb_copy_bits(skb, hdrlen, &payload, sizeof(payload));
  78 -       tmp.h_proto = payload.proto;
  79 -
  80 -       if (likely((!is_amsdu && ether_addr_equal(payload.hdr, rfc1042_header) &&
  81 +       if (likely(skb_copy_bits(skb, hdrlen, &payload, sizeof(payload)) == 0) &&
  82 +           likely((!is_amsdu && ether_addr_equal(payload.hdr, rfc1042_header) &&
  83                     tmp.h_proto != htons(ETH_P_AARP) &&
  84                     tmp.h_proto != htons(ETH_P_IPX)) ||
  85 -                  ether_addr_equal(payload.hdr, bridge_tunnel_header)))
  86 +                  ether_addr_equal(payload.hdr, bridge_tunnel_header))) {
  87                 /* remove RFC1042 or Bridge-Tunnel encapsulation and
  88                  * replace EtherType */
  89                 hdrlen += ETH_ALEN + 2;
  90 -       else
  91 +               tmp.h_proto = payload.proto;
  92 +       } else {
  93                 tmp.h_proto = htons(skb->len - hdrlen);
  94 +       }
  95
  96         pskb_pull(skb, hdrlen);
  97