wireless: drop invalid mesh address extension frames

commit 7dd111e8ee10cc6816669eabcad3334447673236 upstream.

The mesh header can have address extension by a 4th
or a 5th and 6th address, but never both. Drop such
frames in 802.11 -> 802.3 conversion along with any
frames that have the wrong extension.

Reviewed-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 22fb802..61a09e3 100644 (file)
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -304,18 +304,15 @@ EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
 static int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
 {
        int ae = meshhdr->flags & MESH_FLAGS_AE;
-       /* 7.1.3.5a.2 */
+       /* 802.11-2012, 8.2.4.7.3 */
        switch (ae) {
+       default:
        case 0:
                return 6;
        case MESH_FLAGS_AE_A4:
                return 12;
        case MESH_FLAGS_AE_A5_A6:
                return 18;
-       case (MESH_FLAGS_AE_A4 | MESH_FLAGS_AE_A5_A6):
-               return 24;
-       default:
-               return 6;
        }
 }
 
@@ -365,6 +362,8 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
                        /* make sure meshdr->flags is on the linear part */
                        if (!pskb_may_pull(skb, hdrlen + 1))
                                return -1;
+                       if (meshdr->flags & MESH_FLAGS_AE_A4)
+                               return -1;
                        if (meshdr->flags & MESH_FLAGS_AE_A5_A6) {
                                skb_copy_bits(skb, hdrlen +
                                        offsetof(struct ieee80211s_hdr, eaddr1),
@@ -389,6 +388,8 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
                        /* make sure meshdr->flags is on the linear part */
                        if (!pskb_may_pull(skb, hdrlen + 1))
                                return -1;
+                       if (meshdr->flags & MESH_FLAGS_AE_A5_A6)
+                               return -1;
                        if (meshdr->flags & MESH_FLAGS_AE_A4)
                                skb_copy_bits(skb, hdrlen +
                                        offsetof(struct ieee80211s_hdr, eaddr1),