mac80211: check management frame header length

Due to pskb_may_pull() checking the skb length, all
non-management frames are checked on input whether
their 802.11 header is fully present. Also add that
check for management frames and remove a check that
is now duplicate. This prevents accessing skb data
beyond the frame end.

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

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index c6865f2f47f80320c4a5b5b58b88d0a56a187435..99cdee16e31bb516a698ff2ce0444ac1498d4825 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1470,7 +1470,6 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
        frag = sc & IEEE80211_SCTL_FRAG;
 
        if (likely((!ieee80211_has_morefrags(fc) && frag == 0) ||
-                  (rx->skb)->len < 24 ||
                   is_multicast_ether_addr(hdr->addr1))) {
                /* not fragmented */
                goto out;
@@ -2915,10 +2914,15 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
        if (ieee80211_is_data(fc) || ieee80211_is_mgmt(fc))
                local->dot11ReceivedFragmentCount++;
 
-       if (ieee80211_is_mgmt(fc))
-               err = skb_linearize(skb);
-       else
+       if (ieee80211_is_mgmt(fc)) {
+               /* drop frame if too short for header */
+               if (skb->len < ieee80211_hdrlen(fc))
+                       err = -ENOBUFS;
+               else
+                       err = skb_linearize(skb);
+       } else {
                err = !pskb_may_pull(skb, ieee80211_hdrlen(fc));
+       }
 
        if (err) {
                dev_kfree_skb(skb);