The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8c279e9394cade640ed86ec6c6645a0e7df5e0b6 Mon Sep 17 00:00:00 2001

From: Laurent Pinchart laurent.pinchart@ideasonboard.com Date: Mon, 29 Jul 2019 23:14:55 -0300 Subject: [PATCH] media: uvcvideo: Fix error path in control parsing failure

When parsing the UVC control descriptors fails, the error path tries to cleanup a media device that hasn't been initialised, potentially resulting in a crash. Fix this by initialising the media device before the error handling path can be reached.

Fixes: 5a254d751e52 ("[media] uvcvideo: Register a v4l2_device") Reported-by: syzbot+c86454eb3af9e8a4da20@syzkaller.appspotmail.com Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Signed-off-by: Mauro Carvalho Chehab mchehab+samsung@kernel.org

diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index 66ee168ddc7e..428235ca2635 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -2151,6 +2151,20 @@ static int uvc_probe(struct usb_interface *intf, sizeof(dev->name) - len); }

+ /* Initialize the media device. */ +#ifdef CONFIG_MEDIA_CONTROLLER + dev->mdev.dev = &intf->dev; + strscpy(dev->mdev.model, dev->name, sizeof(dev->mdev.model)); + if (udev->serial) + strscpy(dev->mdev.serial, udev->serial, + sizeof(dev->mdev.serial)); + usb_make_path(udev, dev->mdev.bus_info, sizeof(dev->mdev.bus_info)); + dev->mdev.hw_revision = le16_to_cpu(udev->descriptor.bcdDevice); + media_device_init(&dev->mdev); + + dev->vdev.mdev = &dev->mdev; +#endif + /* Parse the Video Class control descriptor. */ if (uvc_parse_control(dev) < 0) { uvc_trace(UVC_TRACE_PROBE, "Unable to parse UVC " @@ -2171,19 +2185,7 @@ static int uvc_probe(struct usb_interface *intf, "linux-uvc-devel mailing list.\n"); }

- /* Initialize the media device and register the V4L2 device. */ -#ifdef CONFIG_MEDIA_CONTROLLER - dev->mdev.dev = &intf->dev; - strscpy(dev->mdev.model, dev->name, sizeof(dev->mdev.model)); - if (udev->serial) - strscpy(dev->mdev.serial, udev->serial, - sizeof(dev->mdev.serial)); - usb_make_path(udev, dev->mdev.bus_info, sizeof(dev->mdev.bus_info)); - dev->mdev.hw_revision = le16_to_cpu(udev->descriptor.bcdDevice); - media_device_init(&dev->mdev); - - dev->vdev.mdev = &dev->mdev; -#endif + /* Register the V4L2 device. */ if (v4l2_device_register(&intf->dev, &dev->vdev) < 0) goto error;