* smatch stuff: potential read past the end of the buffer
@ 2010-12-20 8:30 Dan Carpenter
2010-12-20 9:26 ` Senthil Balasubramanian
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Dan Carpenter @ 2010-12-20 8:30 UTC (permalink / raw)
To: Vasanthakumar Thiagarajan; +Cc: linux-wireless, ath9k-devel
Hello Vasanthakumar,
Smatch complains that in linux-next 60e0c3a7 "ath9k_hw: Eeeprom changes
for AR9485" means there is a potential read past the end of the buffer
int ar9300_eeprom_restore_internal().
drivers/net/wireless/ath/ath9k/ar9003_eeprom.c +3381
ar9300_eeprom_restore_internal(81)
error: buffer overflow 'word' 2048 <= 4099
"word" is allocated with 2048 bytes:
word = kzalloc(2048, GFP_KERNEL);
"length" can be up to 4099:
if ((!AR_SREV_9485(ah) && length >= 1024) ||
(AR_SREV_9485(ah) && length >= (4 * 1024))) {
^^^^^^^^^^^^^^^^^^^^^
so "osize" can be up to 4099 as well:
osize = length;
We're reading way past the end of the word array here:
mchecksum = word[COMP_HDR_LEN + osize] |
^^^^^^^^^^^^^^^^^^^^^^^^^^
(word[COMP_HDR_LEN + osize + 1] << 8);
I don't know how to fix this. Can you take a look?
regards,
dan carpenter
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: smatch stuff: potential read past the end of the buffer
2010-12-20 8:30 smatch stuff: potential read past the end of the buffer Dan Carpenter
@ 2010-12-20 9:26 ` Senthil Balasubramanian
2010-12-20 10:16 ` Arend Van Spriel
2010-12-21 7:29 ` Vasanthakumar Thiagarajan
2 siblings, 0 replies; 6+ messages in thread
From: Senthil Balasubramanian @ 2010-12-20 9:26 UTC (permalink / raw)
To: Dan Carpenter
Cc: Vasanth Thiagarajan, linux-wireless@vger.kernel.org,
ath9k-devel@lists.ath9k.org
On Mon, Dec 20, 2010 at 02:00:41PM +0530, Dan Carpenter wrote:
> Hello Vasanthakumar,
>
> Smatch complains that in linux-next 60e0c3a7 "ath9k_hw: Eeeprom changes
> for AR9485" means there is a potential read past the end of the buffer
> int ar9300_eeprom_restore_internal().
>
> drivers/net/wireless/ath/ath9k/ar9003_eeprom.c +3381
> ar9300_eeprom_restore_internal(81)
> error: buffer overflow 'word' 2048 <= 4099
>
> "word" is allocated with 2048 bytes:
> word = kzalloc(2048, GFP_KERNEL);
>
> "length" can be up to 4099:
> if ((!AR_SREV_9485(ah) && length >= 1024) ||
> (AR_SREV_9485(ah) && length >= (4 * 1024))) {
> ^^^^^^^^^^^^^^^^^^^^^
>
> so "osize" can be up to 4099 as well:
> osize = length;
>
> We're reading way past the end of the word array here:
> mchecksum = word[COMP_HDR_LEN + osize] |
> ^^^^^^^^^^^^^^^^^^^^^^^^^^
> (word[COMP_HDR_LEN + osize + 1] << 8);
>
> I don't know how to fix this. Can you take a look?
thanks for pointing this out. we shall look into this.
>
> regards,
> dan carpenter
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: smatch stuff: potential read past the end of the buffer
2010-12-20 8:30 smatch stuff: potential read past the end of the buffer Dan Carpenter
2010-12-20 9:26 ` Senthil Balasubramanian
@ 2010-12-20 10:16 ` Arend Van Spriel
2010-12-20 12:42 ` Dan Carpenter
2010-12-21 7:29 ` Vasanthakumar Thiagarajan
2 siblings, 1 reply; 6+ messages in thread
From: Arend Van Spriel @ 2010-12-20 10:16 UTC (permalink / raw)
To: Dan Carpenter, Vasanthakumar Thiagarajan
Cc: linux-wireless@vger.kernel.org, ath9k-devel@lists.ath9k.org
Hi Dan,
Why not use min() function?
index = min(COMP_HDR_LEN + osize, 2046);
mchecksum = word[index] |
(word[index + 1] << 8);
Or would smatch miss this in its analysis?
Gr. AvS
________________________________________
From: linux-wireless-owner@vger.kernel.org [linux-wireless-owner@vger.kernel.org] On Behalf Of Dan Carpenter [error27@gmail.com]
Sent: Monday, December 20, 2010 9:30 AM
To: Vasanthakumar Thiagarajan
Cc: linux-wireless@vger.kernel.org; ath9k-devel@lists.ath9k.org
Subject: smatch stuff: potential read past the end of the buffer
Hello Vasanthakumar,
Smatch complains that in linux-next 60e0c3a7 "ath9k_hw: Eeeprom changes
for AR9485" means there is a potential read past the end of the buffer
int ar9300_eeprom_restore_internal().
drivers/net/wireless/ath/ath9k/ar9003_eeprom.c +3381
ar9300_eeprom_restore_internal(81)
error: buffer overflow 'word' 2048 <= 4099
"word" is allocated with 2048 bytes:
word = kzalloc(2048, GFP_KERNEL);
"length" can be up to 4099:
if ((!AR_SREV_9485(ah) && length >= 1024) ||
(AR_SREV_9485(ah) && length >= (4 * 1024))) {
^^^^^^^^^^^^^^^^^^^^^
so "osize" can be up to 4099 as well:
osize = length;
We're reading way past the end of the word array here:
mchecksum = word[COMP_HDR_LEN + osize] |
^^^^^^^^^^^^^^^^^^^^^^^^^^
(word[COMP_HDR_LEN + osize + 1] << 8);
I don't know how to fix this. Can you take a look?
regards,
dan carpenter
--
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: smatch stuff: potential read past the end of the buffer
2010-12-20 10:16 ` Arend Van Spriel
@ 2010-12-20 12:42 ` Dan Carpenter
2010-12-20 17:13 ` Arend Van Spriel
0 siblings, 1 reply; 6+ messages in thread
From: Dan Carpenter @ 2010-12-20 12:42 UTC (permalink / raw)
To: Arend Van Spriel
Cc: Vasanthakumar Thiagarajan, linux-wireless@vger.kernel.org,
ath9k-devel@lists.ath9k.org
On Mon, Dec 20, 2010 at 02:16:56AM -0800, Arend Van Spriel wrote:
> Hi Dan,
>
> Why not use min() function?
> index = min(COMP_HDR_LEN + osize, 2046);
> mchecksum = word[index] |
> (word[index + 1] << 8);
>
> Or would smatch miss this in its analysis?
That would silence the warning, but is it the right fix? I thought
maybe we should make word a larger buffer?
regards,
dan carpenter
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: smatch stuff: potential read past the end of the buffer
2010-12-20 12:42 ` Dan Carpenter
@ 2010-12-20 17:13 ` Arend Van Spriel
0 siblings, 0 replies; 6+ messages in thread
From: Arend Van Spriel @ 2010-12-20 17:13 UTC (permalink / raw)
To: Dan Carpenter
Cc: Vasanthakumar Thiagarajan, linux-wireless@vger.kernel.org,
ath9k-devel@lists.ath9k.org
Hi Dan,
Agreed. But maybe there is no usage scenario in which the boundary is actually crossed. Have to wait for ath9k developers to answer that.
Gr. AvS
________________________________________
From: Dan Carpenter [error27@gmail.com]
Sent: Monday, December 20, 2010 1:42 PM
To: Arend Van Spriel
Cc: Vasanthakumar Thiagarajan; linux-wireless@vger.kernel.org; ath9k-devel@lists.ath9k.org
Subject: Re: smatch stuff: potential read past the end of the buffer
On Mon, Dec 20, 2010 at 02:16:56AM -0800, Arend Van Spriel wrote:
> Hi Dan,
>
> Why not use min() function?
> index = min(COMP_HDR_LEN + osize, 2046);
> mchecksum = word[index] |
> (word[index + 1] << 8);
>
> Or would smatch miss this in its analysis?
That would silence the warning, but is it the right fix? I thought
maybe we should make word a larger buffer?
regards,
dan carpenter
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: smatch stuff: potential read past the end of the buffer
2010-12-20 8:30 smatch stuff: potential read past the end of the buffer Dan Carpenter
2010-12-20 9:26 ` Senthil Balasubramanian
2010-12-20 10:16 ` Arend Van Spriel
@ 2010-12-21 7:29 ` Vasanthakumar Thiagarajan
2 siblings, 0 replies; 6+ messages in thread
From: Vasanthakumar Thiagarajan @ 2010-12-21 7:29 UTC (permalink / raw)
To: Dan Carpenter
Cc: Vasanth Thiagarajan, linux-wireless@vger.kernel.org,
ath9k-devel@lists.ath9k.org
On Mon, Dec 20, 2010 at 02:00:41PM +0530, Dan Carpenter wrote:
> Hello Vasanthakumar,
>
> Smatch complains that in linux-next 60e0c3a7 "ath9k_hw: Eeeprom changes
> for AR9485" means there is a potential read past the end of the buffer
> int ar9300_eeprom_restore_internal().
>
> drivers/net/wireless/ath/ath9k/ar9003_eeprom.c +3381
> ar9300_eeprom_restore_internal(81)
> error: buffer overflow 'word' 2048 <= 4099
>
> "word" is allocated with 2048 bytes:
> word = kzalloc(2048, GFP_KERNEL);
>
> "length" can be up to 4099:
> if ((!AR_SREV_9485(ah) && length >= 1024) ||
> (AR_SREV_9485(ah) && length >= (4 * 1024))) {
Yeah, this looks buggy, the eeprom data length for AR9485 is 1088
bytes only, I'll send out a patch, thanks for reporting this.
Vasanth
^ permalink raw reply [flat|nested] 6+ messages in thread
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2010-12-20 8:30 smatch stuff: potential read past the end of the buffer Dan Carpenter
2010-12-20 9:26 ` Senthil Balasubramanian
2010-12-20 10:16 ` Arend Van Spriel
2010-12-20 12:42 ` Dan Carpenter
2010-12-20 17:13 ` Arend Van Spriel
2010-12-21 7:29 ` Vasanthakumar Thiagarajan
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