[PATCH 4.9 15/60] mac80211: strictly check mesh address extension mode

Greg Kroah-Hartman
2017-06-19T16:08:15Z

From: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/mac80211/rx.c | 3 ++-
net/wireless/util.c | 10 ++++++----
2 files changed, 8 insertions(+), 5 deletions(-)

--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2471,7 +2471,8 @@ ieee80211_rx_h_mesh_fwding(struct ieee80
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;
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -454,6 +454,8 @@ int ieee80211_data_to_8023_exthdr(struct
if (iftype == NL80211_IFTYPE_MESH_POINT)
skb_copy_bits(skb, hdrlen, &mesh_flags, 1);

+ mesh_flags &= MESH_FLAGS_AE;
+
switch (hdr->frame_control &
cpu_to_le16(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
case cpu_to_le16(IEEE80211_FCTL_TODS):
@@ -469,9 +471,9 @@ int ieee80211_data_to_8023_exthdr(struct
iftype != NL80211_IFTYPE_STATION))
return -1;
if (iftype == NL80211_IFTYPE_MESH_POINT) {
- if (mesh_flags & MESH_FLAGS_AE_A4)
+ if (mesh_flags == MESH_FLAGS_AE_A4)
return -1;
- if (mesh_flags & MESH_FLAGS_AE_A5_A6) {
+ if (mesh_flags == MESH_FLAGS_AE_A5_A6) {
skb_copy_bits(skb, hdrlen +
offsetof(struct ieee80211s_hdr, eaddr1),
tmp.h_dest, 2 * ETH_ALEN);
@@ -487,9 +489,9 @@ int ieee80211_data_to_8023_exthdr(struct
ether_addr_equal(tmp.h_source, addr)))
return -1;
if (iftype == NL80211_IFTYPE_MESH_POINT) {
- if (mesh_flags & MESH_FLAGS_AE_A5_A6)
+ if (mesh_flags == MESH_FLAGS_AE_A5_A6)
return -1;
- if (mesh_flags & MESH_FLAGS_AE_A4)
+ if (mesh_flags == MESH_FLAGS_AE_A4)
skb_copy_bits(skb, hdrlen +
offsetof(struct ieee80211s_hdr, eaddr1),
tmp.h_source, ETH_ALEN);