[PATCH 3.8 52/91] mac80211: fix crash if bitrate calculation goes wrong

[Kamal Mostafa]

3.8.13.13 -stable review patch.  If anyone has any objections, please let me know.

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

From: Johannes Berg <johannes.berg@xxxxxxxxx>

commit d86aa4f8ca58898ec6a94c0635da20b948171ed7 upstream.

If a frame's timestamp is calculated, and the bitrate
calculation goes wrong and returns zero, the system
will attempt to divide by zero and crash. Catch this
case and print the rate information that the driver
reported when this happens.

Reported-by: Thomas Lindroth <thomas.lindroth@xxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 net/mac80211/util.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index f11e8c5..e0ad72d 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2105,6 +2105,10 @@ u64 ieee80211_calculate_rx_timestamp(struct ieee80211_local *local,
 	}
 
 	rate = cfg80211_calculate_bitrate(&ri);
+	if (WARN_ONCE(!rate,
+		      "Invalid bitrate: flags=0x%x, idx=%d, vht_nss=%d\n",
+		      status->flag, status->rate_idx, status->vht_nss))
+		return 0;
 
 	/* rewind from end of MPDU */
 	if (status->flag & RX_FLAG_MACTIME_END)
-- 
1.8.1.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/