lkml.org 
[lkml]   [2019]   [Nov]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] usb: appledisplay: fix use-after-free in bl_get_brightness
Date
In context of USB disconnect, the delaywork trigger and calling
appledisplay_bl_get_brightness() and the msgdata was freed.

add the checking return value of usb_control_msg() and only update the
data while the retval is valid.

Reported-by: syzbot+495dab1f175edc9c2f13@syzkaller.appspotmail.com
Reported-and-tested-by:
syzbot+495dab1f175edc9c2f13@syzkaller.appspotmail.com

https://groups.google.com/d/msg/syzkaller-bugs/dRmkh2UYusY/l2a6Mg3FAQAJ

Signed-off-by: Phong Tran <tranmanphong@gmail.com>
---
drivers/usb/misc/appledisplay.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/misc/appledisplay.c b/drivers/usb/misc/appledisplay.c
index ac92725458b5..3e3dfa5a3954 100644
--- a/drivers/usb/misc/appledisplay.c
+++ b/drivers/usb/misc/appledisplay.c
@@ -164,7 +164,8 @@ static int appledisplay_bl_get_brightness(struct backlight_device *bd)
0,
pdata->msgdata, 2,
ACD_USB_TIMEOUT);
- brightness = pdata->msgdata[1];
+ if (retval >= 0)
+ brightness = pdata->msgdata[1];
mutex_unlock(&pdata->sysfslock);

if (retval < 0)
--
2.20.1
\
 
 \ /
  Last update: 2019-11-06 00:37    [W:0.083 / U:0.140 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site