[ipxe-devel] [PATCH 1/1] ath9k: fix buffer overrun for ar9287

[Christian Hesse]

From: Christian Hesse <mail at eworm.de>

This backport is from linux kernel upstream commit:

> commit 83d6f1f15f8cce844b0a131cbc63e444620e48b5
> Author: Arnd Bergmann <arnd at arndb.de>
> Date:   Mon Mar 14 15:18:36 2016 +0100
>
> ath9k: fix buffer overrun for ar9287
>
> Code that was added back in 2.6.38 has an obvious overflow
> when accessing a static array, and at the time it was added
> only a code comment was put in front of it as a reminder
> to have it reviewed properly.
>
> This has not happened, but gcc-6 now points to the specific
> overflow:
>
> drivers/net/wireless/ath/ath9k/eeprom.c: In function 'ath9k_hw_get_gain_boundaries_pdadcs':
> drivers/net/wireless/ath/ath9k/eeprom.c:483:44: error: array subscript is above array bounds [-Werror=array-bounds]
>      maxPwrT4[i] = data_9287[idxL].pwrPdg[i][4];
>                    ~~~~~~~~~~~~~~~~~~~~~~~~~^~~
>
> It turns out that the correct array length exists in the local
> 'intercepts' variable of this function, so we can just use that
> instead of hardcoding '4', so this patch changes all three
> instances to use that variable. The other two instances were
> already correct, but it's more consistent this way.
>
> Signed-off-by: Arnd Bergmann <arnd at arndb.de>
> Fixes: 940cd2c12ebf ("ath9k_hw: merge the ar9287 version of ath9k_hw_get_gain_boundaries_pdadcs")
> Signed-off-by: David S. Miller <davem at davemloft.net>

Signed-off-by: Christian Hesse <mail at eworm.de>
---
 src/drivers/net/ath/ath9k/ath9k_eeprom.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/drivers/net/ath/ath9k/ath9k_eeprom.c b/src/drivers/net/ath/ath9k/ath9k_eeprom.c
index f552aca..a204237 100644
--- a/src/drivers/net/ath/ath9k/ath9k_eeprom.c
+++ b/src/drivers/net/ath/ath9k/ath9k_eeprom.c
@@ -368,10 +368,9 @@ void ath9k_hw_get_gain_boundaries_pdadcs(struct ath_hw *ah,
 
 	if (match) {
 		if (AR_SREV_9287(ah)) {
-			/* FIXME: array overrun? */
 			for (i = 0; i < numXpdGains; i++) {
 				minPwrT4[i] = data_9287[idxL].pwrPdg[i][0];
-				maxPwrT4[i] = data_9287[idxL].pwrPdg[i][4];
+				maxPwrT4[i] = data_9287[idxL].pwrPdg[i][intercepts - 1];
 				ath9k_hw_fill_vpd_table(minPwrT4[i], maxPwrT4[i],
 						data_9287[idxL].pwrPdg[i],
 						data_9287[idxL].vpdPdg[i],
@@ -381,7 +380,7 @@ void ath9k_hw_get_gain_boundaries_pdadcs(struct ath_hw *ah,
 		} else if (eeprom_4k) {
 			for (i = 0; i < numXpdGains; i++) {
 				minPwrT4[i] = data_4k[idxL].pwrPdg[i][0];
-				maxPwrT4[i] = data_4k[idxL].pwrPdg[i][4];
+				maxPwrT4[i] = data_4k[idxL].pwrPdg[i][intercepts - 1];
 				ath9k_hw_fill_vpd_table(minPwrT4[i], maxPwrT4[i],
 						data_4k[idxL].pwrPdg[i],
 						data_4k[idxL].vpdPdg[i],
@@ -391,7 +390,7 @@ void ath9k_hw_get_gain_boundaries_pdadcs(struct ath_hw *ah,
 		} else {
 			for (i = 0; i < numXpdGains; i++) {
 				minPwrT4[i] = data_def[idxL].pwrPdg[i][0];
-				maxPwrT4[i] = data_def[idxL].pwrPdg[i][4];
+				maxPwrT4[i] = data_def[idxL].pwrPdg[i][intercepts - 1];
 				ath9k_hw_fill_vpd_table(minPwrT4[i], maxPwrT4[i],
 						data_def[idxL].pwrPdg[i],
 						data_def[idxL].vpdPdg[i],
-- 
2.8.2