Hi Oliver, On Tue, Feb 11, 2020 at 03:31:30PM +0100, Oliver Neukum wrote: > Am Montag, den 10.02.2020, 16:18 +0200 schrieb Laurent Pinchart: > > On Mon, Feb 10, 2020 at 03:13:26PM +0100, Oliver Neukum wrote: > > > Am Montag, den 13.01.2020, 04:24 -0800 schrieb syzbot: > > > > Hello, > > > > > > > > syzbot found the following crash on: > > > > > > > > HEAD commit: ae179410 usb: gadget: add raw-gadget interface > > > > git tree: https://github.com/google/kasan.git usb-fuzzer > > > > console output: https://syzkaller.appspot.com/x/log.txt?x=132223fee00000 > > > > kernel config: https://syzkaller.appspot.com/x/.config?x=ad1d751a3a72ae57 > > > > dashboard link: https://syzkaller.appspot.com/bug?extid=9a48339b077c5a80b869 > > > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16857325e00000 > > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=142e069ee00000 > > > > > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > > > Reported-by: syzbot+9a48339b077c5a80b869@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > > > > > usb 1-1: New USB device found, idVendor=0bd3, idProduct=0555, > > > > bcdDevice=69.6a > > > > usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0 > > > > usb 1-1: config 0 descriptor?? > > > > usb 1-1: string descriptor 0 read error: -71 > > > > uvcvideo: Found UVC 0.00 device <unnamed> (0bd3:0555) > > > > ================================================================== > > > > BUG: KASAN: use-after-free in uvc_register_terms > > > > drivers/media/usb/uvc/uvc_driver.c:2038 [inline] > > > > BUG: KASAN: use-after-free in uvc_register_chains > > > > drivers/media/usb/uvc/uvc_driver.c:2070 [inline] > > > > BUG: KASAN: use-after-free in uvc_probe.cold+0x2193/0x29de > > > > drivers/media/usb/uvc/uvc_driver.c:2201 > > > > Read of size 2 at addr ffff8881d4f1bc2e by task kworker/1:2/94 > > > > > > #syz test: https://github.com/google/kasan.git ae179410 > > > > > > From db844641a5e30f3cfc0ce9cde156b3cc356b6c0c Mon Sep 17 00:00:00 2001 > > > From: Oliver Neukum <oneukum@xxxxxxxx> > > > Date: Mon, 10 Feb 2020 15:10:36 +0100 > > > Subject: [PATCH] UVC: deal with unnamed streams > > > > > > The pointer can be NULL > > > > > > Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx> > > > --- > > > drivers/media/usb/uvc/uvc_driver.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > > > index 99883550375e..26558a89f2fe 100644 > > > --- a/drivers/media/usb/uvc/uvc_driver.c > > > +++ b/drivers/media/usb/uvc/uvc_driver.c > > > @@ -2069,7 +2069,8 @@ static int uvc_register_terms(struct uvc_device *dev, > > > stream = uvc_stream_by_id(dev, term->id); > > > if (stream == NULL) { > > > uvc_printk(KERN_INFO, "No streaming interface found " > > > - "for terminal %u.", term->id); > > > + "for terminal %u.", > > > + term->id ? term->id : "(Unnamed)"); > > > > Have you tried compiling this ? > > Yes. It does compile. Why? Because term->id is a u8, "(Unnamed)" is a const char *, and %u requires an integer. I'm surprised the compiler doesn't complain, but in any case, it's not right :-) -- Regards, Laurent Pinchart
