From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Hovold Subject: Re: [PATCH v2 4/9] ALSA: line6: Add a sanity check for invalid EPs Date: Wed, 11 Oct 2017 16:28:37 +0200 Message-ID: <20171011142837.GZ4269@localhost> References: <20171011103646.11879-1-tiwai@suse.de> <20171011103646.11879-5-tiwai@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-lf0-f67.google.com (mail-lf0-f67.google.com [209.85.215.67]) by alsa0.perex.cz (Postfix) with ESMTP id 19A75266CA1 for ; Wed, 11 Oct 2017 16:28:35 +0200 (CEST) Received: by mail-lf0-f67.google.com with SMTP id j73so805830lfg.0 for ; Wed, 11 Oct 2017 07:28:35 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20171011103646.11879-5-tiwai@suse.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Takashi Iwai Cc: Andrey Konovalov , alsa-devel@alsa-project.org, linux-usb@vger.kernel.org, Greg KH List-Id: alsa-devel@alsa-project.org On Wed, Oct 11, 2017 at 12:36:41PM +0200, Takashi Iwai wrote: > As syzkaller spotted, currently line6 drivers submit a URB with the > fixed EP without checking whether it's actually available, which may > result in a kernel warning like: > usb 1-1: BOGUS urb xfer, pipe 3 != type 1 > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 24 at drivers/usb/core/urb.c:449 > usb_submit_urb+0xf8a/0x11d0 > Modules linked in: > CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted 4.14.0-rc2-42613-g1488251d1a98 #238 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > Workqueue: usb_hub_wq hub_event > Call Trace: > line6_start_listen+0x55f/0x9e0 sound/usb/line6/driver.c:82 > line6_init_cap_control sound/usb/line6/driver.c:690 > line6_probe+0x7c9/0x1310 sound/usb/line6/driver.c:764 > podhd_probe+0x64/0x70 sound/usb/line6/podhd.c:474 > usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361 > .... > > This patch adds a sanity check of validity of EPs at the device > initialization phase for avoiding the call with an invalid EP. > > Reported-by: Andrey Konovalov > Tested-by: Andrey Konovalov > Signed-off-by: Takashi Iwai > --- > sound/usb/line6/driver.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c > index 0ff5a7d2e19f..0da6f68761e3 100644 > --- a/sound/usb/line6/driver.c > +++ b/sound/usb/line6/driver.c > @@ -78,6 +78,13 @@ static int line6_start_listen(struct usb_line6 *line6) > line6->buffer_listen, LINE6_BUFSIZE_LISTEN, > line6_data_received, line6); > } > + > + /* sanity checks of EP before actually submitting */ > + if (usb_urb_ep_type_check(line6->urb_listen)) { > + dev_err(line6->ifcdev, "invalid control EP\n"); > + return -EINVAL; > + } You're now doing this check twice (here and in usb_submit_urb) every time this URB is submitted rather just checking it once in probe. Seems like a quick band-aid to me. > + > line6->urb_listen->actual_length = 0; > err = usb_submit_urb(line6->urb_listen, GFP_ATOMIC); > return err; Johan