[014/241] mac80211: make sure data is accessible in EAPOL check

Submitted by Herton Ronaldo Krzesinski on Dec. 13, 2012, 1:56 p.m.

Details

Message ID 1355407206-17100-15-git-send-email-herton.krzesinski@canonical.com
State New
Headers show

Commit Message

Herton Ronaldo Krzesinski Dec. 13, 2012, 1:56 p.m.
3.5.7.2 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johannes Berg <johannes.berg@intel.com>

commit 6dbda2d00d466225f9db1dc695ff852443f28832 upstream.

The code to allow EAPOL frames even when the station
isn't yet marked associated needs to check that the
incoming frame is long enough and due to paged RX it
also can't assume skb->data contains the right data,
it must use skb_copy_bits(). Fix this to avoid using
data that doesn't really exist.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
 net/mac80211/rx.c |   18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

Patch hide | download patch | download mbox

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 4fd5369..064384c 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -874,14 +874,16 @@  ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
 		 */
 		if (rx->sta && rx->sdata->vif.type == NL80211_IFTYPE_STATION &&
 		    ieee80211_is_data_present(hdr->frame_control)) {
-			u16 ethertype;
-			u8 *payload;
-
-			payload = rx->skb->data +
-				ieee80211_hdrlen(hdr->frame_control);
-			ethertype = (payload[6] << 8) | payload[7];
-			if (cpu_to_be16(ethertype) ==
-			    rx->sdata->control_port_protocol)
+			unsigned int hdrlen;
+			__be16 ethertype;
+
+			hdrlen = ieee80211_hdrlen(hdr->frame_control);
+
+			if (rx->skb->len < hdrlen + 8)
+				return RX_DROP_MONITOR;
+
+			skb_copy_bits(rx->skb, hdrlen + 6, &ethertype, 2);
+			if (ethertype == rx->sdata->control_port_protocol)
 				return RX_CONTINUE;
 		}