net: wireless: ath9k: avoid possible NULL pointer dereference

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 <mina86@mina86.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 54b0415..8918035 100644 (file)
--- 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))