wireless: drop invalid mesh address extension frames

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.

Cc: stable@vger.kernel.org
Reviewed-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/net/wireless/util.c b/net/wireless/util.c
index ef35f4ef2aa6..45a09de1ffe3 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -312,18 +312,15 @@ 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;
         }
 }
 
@@ -373,6 +370,8 @@ 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),
@@ -397,6 +396,8 @@ 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),