[Linux-kernel-mentees] [PATCH] usb: appledisplay: fix use-after-free in bl_get_brightness
Phong Tran
tranmanphong at gmail.com
Tue Nov 5 23:36:52 UTC 2019
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 at syzkaller.appspotmail.com
Reported-and-tested-by:
syzbot+495dab1f175edc9c2f13 at syzkaller.appspotmail.com
https://groups.google.com/d/msg/syzkaller-bugs/dRmkh2UYusY/l2a6Mg3FAQAJ
Signed-off-by: Phong Tran <tranmanphong at 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
More information about the Linux-kernel-mentees
mailing list