2013-11-29 17:06:54

by Michal Nazarewicz

[permalink] [raw]
Subject: [PATCH] net: wireless: ath9k: avoid possible NULL pointer dereference

From: Michal Nazarewicz <[email protected]>

Code in ath9k_hw_set_clockrate function indicates that ah->curchan
(and thus chan local variable) may be NULL. If that is indeed the
case, IS_CHAN_HT40(chan) check has to be performed only in branch
where chan is not NULL. Moving the code under already existing
if condition fixes this issue.

Signed-off-by: Michal Nazarewicz <[email protected]>
---
drivers/net/wireless/ath/ath9k/hw.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 54b0415..8918035 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -146,10 +146,9 @@ static void ath9k_hw_set_clockrate(struct ath_hw *ah)
else
clockrate = ATH9K_CLOCK_RATE_5GHZ_OFDM;

- if (IS_CHAN_HT40(chan))
- clockrate *= 2;
-
- if (ah->curchan) {
+ if (chan) {
+ if (IS_CHAN_HT40(chan))
+ clockrate *= 2;
if (IS_CHAN_HALF_RATE(chan))
clockrate /= 2;
if (IS_CHAN_QUARTER_RATE(chan))
--
1.8.4.1