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>