mac80211: fix crash if bitrate calculation goes wrong

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@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 72e6292955bb9eb3b896088d3dc756771e1ed3b4..5db8eb5d56cf9ed24061840ab3a0349a297d6db0 100644 (file)
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2174,6 +2174,10 @@ 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)