mac80211: strictly check mesh address extension mode

commit 5667c86acf021e6dcf02584408b4484a273ac68f upstream.

Mesh forwarding path checks for address extension mode to fetch
appropriate proxied address and MPP address. Existing condition
that looks for 6 address format is not strict enough so that
frames with improper values are processed and invalid entries
are added into MPP table. Fix that by adding a stricter check before
processing the packet.

Per IEEE Std 802.11s-2011 spec. Table 7-6g1 lists address extension
mode 0x3 as reserved one. And also Table Table 9-13 does not specify
0x3 as valid address field.

Fixes: 9b395bc3be1c ("mac80211: verify that skb data is present")
Signed-off-by: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
[bwh: Backported to 3.2: add mesh_flags variable in ieee80211_data_to_8023(),
 added separately upstream]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 96c34c1..0cfb95a 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1959,7 +1959,8 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
                if (is_multicast_ether_addr(hdr->addr1)) {
                        mpp_addr = hdr->addr3;
                        proxied_addr = mesh_hdr->eaddr1;
-               } else if (mesh_hdr->flags & MESH_FLAGS_AE_A5_A6) {
+               } else if ((mesh_hdr->flags & MESH_FLAGS_AE) ==
+                           MESH_FLAGS_AE_A5_A6) {
                        /* has_a4 already checked in ieee80211_rx_mesh_check */
                        mpp_addr = hdr->addr4;
                        proxied_addr = mesh_hdr->eaddr2;

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 5fba039..870c52d 100644 (file)
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -360,12 +360,15 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
                if (iftype == NL80211_IFTYPE_MESH_POINT) {
                        struct ieee80211s_hdr *meshdr =
                                (struct ieee80211s_hdr *) (skb->data + hdrlen);
+                       u8 mesh_flags;
+
                        /* 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)
+                       mesh_flags = meshdr->flags & MESH_FLAGS_AE;
+                       if (mesh_flags == MESH_FLAGS_AE_A4)
                                return -1;
-                       if (meshdr->flags & MESH_FLAGS_AE_A5_A6) {
+                       if (mesh_flags == MESH_FLAGS_AE_A5_A6) {
                                skb_copy_bits(skb, hdrlen +
                                        offsetof(struct ieee80211s_hdr, eaddr1),
                                        dst, ETH_ALEN);
@@ -386,12 +389,15 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
                if (iftype == NL80211_IFTYPE_MESH_POINT) {
                        struct ieee80211s_hdr *meshdr =
                                (struct ieee80211s_hdr *) (skb->data + hdrlen);
+                       u8 mesh_flags;
+
                        /* 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)
+                       mesh_flags = meshdr->flags & MESH_FLAGS_AE;
+                       if (mesh_flags == MESH_FLAGS_AE_A5_A6)
                                return -1;
-                       if (meshdr->flags & MESH_FLAGS_AE_A4)
+                       if (mesh_flags == MESH_FLAGS_AE_A4)
                                skb_copy_bits(skb, hdrlen +
                                        offsetof(struct ieee80211s_hdr, eaddr1),
                                        src, ETH_ALEN);