Messages in this thread Patch in this message | | | From | Phong Tran <> | Subject | [PATCH] usb: appledisplay: fix use-after-free in bl_get_brightness | Date | Wed, 6 Nov 2019 06:36:52 +0700 |
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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
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