media: gspca: zero usb_buf on error

If reg_r() fails, then gspca_dev->usb_buf was left uninitialized,
and some drivers used the contents of that buffer in logic.

This caused several syzbot errors:

https://syzkaller.appspot.com/bug?extid=397fd082ce5143e2f67d
https://syzkaller.appspot.com/bug?extid=1a35278dd0ebfb3a038a
https://syzkaller.appspot.com/bug?extid=06ddf1788cfd048c5e82

I analyzed the gspca drivers and zeroed the buffer where needed.

Reported-and-tested-by: syzbot+1a35278dd0ebfb3a038a@syzkaller.appspotmail.com
Reported-and-tested-by: syzbot+397fd082ce5143e2f67d@syzkaller.appspotmail.com
Reported-and-tested-by: syzbot+06ddf1788cfd048c5e82@syzkaller.appspotmail.com

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Hans Verkuil
2019-08-16 03:38:13 -03:00
committed by Mauro Carvalho Chehab
parent 2509d725e0
commit 4843a543fa
14 changed files with 71 additions and 0 deletions

View File

@@ -425,6 +425,11 @@ static void reg_r(struct gspca_dev *gspca_dev,
if (ret < 0) {
pr_err("reg_r %04x failed %d\n", value, ret);
gspca_dev->usb_err = ret;
/*
* Make sure the buffer is zeroed to avoid uninitialized
* values.
*/
memset(gspca_dev->usb_buf, 0, USB_BUF_SZ);
}
}