usb: fix slab-out-of-bounds Read in cougar_report_fixup

[PATCH] usb: fix slab-out-of-bounds Read in cougar_report_fixup

Posted by Camila Alvarez 1 year, 6 months ago

report_fixup for the Cougar 500k Gaming Keyboard was not verifying
that the report descriptor size was correct before accessing it

Reported-by: syzbot+24c0361074799d02c452@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=24c0361074799d02c452
Signed-off-by: Camila Alvarez <cam.alvarez.i@gmail.com>
---
 drivers/hid/hid-cougar.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hid/hid-cougar.c b/drivers/hid/hid-cougar.c
index cb8bd8aae15b..0fa785f52707 100644
--- a/drivers/hid/hid-cougar.c
+++ b/drivers/hid/hid-cougar.c
@@ -106,7 +106,7 @@ static void cougar_fix_g6_mapping(void)
 static __u8 *cougar_report_fixup(struct hid_device *hdev, __u8 *rdesc,
 				 unsigned int *rsize)
 {
-	if (rdesc[2] == 0x09 && rdesc[3] == 0x02 &&
+	if (*rsize >= 117 && rdesc[2] == 0x09 && rdesc[3] == 0x02 &&
 	    (rdesc[115] | rdesc[116] << 8) >= HID_MAX_USAGES) {
 		hid_info(hdev,
 			"usage count exceeds max: fixing up report descriptor\n");
-- 
2.34.1

Re: [PATCH] usb: fix slab-out-of-bounds Read in cougar_report_fixup

Posted by Jiri Kosina 1 year, 6 months ago

On Tue, 30 Jul 2024, Camila Alvarez wrote:

> report_fixup for the Cougar 500k Gaming Keyboard was not verifying
> that the report descriptor size was correct before accessing it
> 
> Reported-by: syzbot+24c0361074799d02c452@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=24c0361074799d02c452
> Signed-off-by: Camila Alvarez <cam.alvarez.i@gmail.com>

Applied, thanks.

-- 
Jiri Kosina
SUSE Labs

Re: [PATCH] usb: fix slab-out-of-bounds Read in cougar_report_fixup

Posted by Camila Alvarez Inostroza 1 year, 6 months ago


On Thu, 1 Aug 2024, Jiri Kosina wrote:

> On Tue, 30 Jul 2024, Camila Alvarez wrote:
>
>> report_fixup for the Cougar 500k Gaming Keyboard was not verifying
>> that the report descriptor size was correct before accessing it
>>
>> Reported-by: syzbot+24c0361074799d02c452@syzkaller.appspotmail.com
>> Closes: https://syzkaller.appspot.com/bug?extid=24c0361074799d02c452
>> Signed-off-by: Camila Alvarez <cam.alvarez.i@gmail.com>
>
> Applied, thanks.
>
Thank you!
> -- 
> Jiri Kosina
> SUSE Labs
>
>

Re: [PATCH] usb: fix slab-out-of-bounds Read in cougar_report_fixup

Posted by Silvan Jegen 1 year, 6 months ago

On Tue, Jul 30, 2024 at 07:42:43PM -0400, Camila Alvarez wrote:
> report_fixup for the Cougar 500k Gaming Keyboard was not verifying
> that the report descriptor size was correct before accessing it
> 
> Reported-by: syzbot+24c0361074799d02c452@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=24c0361074799d02c452
> Signed-off-by: Camila Alvarez <cam.alvarez.i@gmail.com>
> ---
>  drivers/hid/hid-cougar.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

This LGTM!

Reviewed-by: Silvan Jegen <s.jegen@gmail.com>

> 
> diff --git a/drivers/hid/hid-cougar.c b/drivers/hid/hid-cougar.c
> index cb8bd8aae15b..0fa785f52707 100644
> --- a/drivers/hid/hid-cougar.c
> +++ b/drivers/hid/hid-cougar.c
> @@ -106,7 +106,7 @@ static void cougar_fix_g6_mapping(void)
>  static __u8 *cougar_report_fixup(struct hid_device *hdev, __u8 *rdesc,
>  				 unsigned int *rsize)
>  {
> -	if (rdesc[2] == 0x09 && rdesc[3] == 0x02 &&
> +	if (*rsize >= 117 && rdesc[2] == 0x09 && rdesc[3] == 0x02 &&
>  	    (rdesc[115] | rdesc[116] << 8) >= HID_MAX_USAGES) {
>  		hid_info(hdev,
>  			"usage count exceeds max: fixing up report descriptor\n");
> -- 
> 2.34.1
> 
>