[PATCH 4.1 45/95] mac80211: fix divide by zero when NOA update

From: Greg Kroah-Hartman
Date: Mon Dec 07 2015 - 09:42:12 EST


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

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

From: "Janusz.Dziedzic@xxxxxxxxx" <Janusz.Dziedzic@xxxxxxxxx>

commit 519ee6918b91abdc4bc9720deae17599a109eb40 upstream.

In case of one shot NOA the interval can be 0, catch that
instead of potentially (depending on the driver) crashing
like this:

divide error: 0000 [#1] SMP
[...]
Call Trace:
<IRQ>
[<ffffffffc08e891c>] ieee80211_extend_absent_time+0x6c/0xb0 [mac80211]
[<ffffffffc08e8a17>] ieee80211_update_p2p_noa+0xb7/0xe0 [mac80211]
[<ffffffffc069cc30>] ath9k_p2p_ps_timer+0x170/0x190 [ath9k]
[<ffffffffc070adf8>] ath_gen_timer_isr+0xc8/0xf0 [ath9k_hw]
[<ffffffffc0691156>] ath9k_tasklet+0x296/0x2f0 [ath9k]
[<ffffffff8107ad65>] tasklet_action+0xe5/0xf0
[...]

Signed-off-by: Janusz Dziedzic <janusz.dziedzic@xxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
net/mac80211/util.c | 7 +++++++
1 file changed, 7 insertions(+)

--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2984,6 +2984,13 @@ ieee80211_extend_noa_desc(struct ieee802
if (end > 0)
return false;

+ /* One shot NOA */
+ if (data->count[i] == 1)
+ return false;
+
+ if (data->desc[i].interval == 0)
+ return false;
+
/* End time is in the past, check for repetitions */
skip = DIV_ROUND_UP(-end, data->desc[i].interval);
if (data->count[i] < 255) {


--
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/