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| author | Alan Stern <stern@rowland.harvard.edu> | 2019-10-07 18:09:04 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-11-29 12:10:05 +0300 |
| commit | ddac4e34010ac954c840274d4c0b0fd4eabc09ae (patch) | |
| tree | 6f7e3e58891181d3ef9682ea1be0248f6a6180fc | |
| parent | 5aa7ad7e991e6cb0c3a1825dbe7f78c2a8116ccc (diff) | |
| download | linux-ddac4e34010ac954c840274d4c0b0fd4eabc09ae.tar.xz | |
media: usbvision: Fix invalid accesses after device disconnect
commit c7a191464078262bf799136317c95824e26a222b upstream.
The syzbot fuzzer found two invalid-access bugs in the usbvision
driver. These bugs occur when userspace keeps the device file open
after the device has been disconnected and usbvision_disconnect() has
set usbvision->dev to NULL:
When the device file is closed, usbvision_radio_close() tries
to issue a usb_set_interface() call, passing the NULL pointer
as its first argument.
If userspace performs a querycap ioctl call, vidioc_querycap()
calls usb_make_path() with the same NULL pointer.
This patch fixes the problems by making the appropriate tests
beforehand. Note that vidioc_querycap() is protected by
usbvision->v4l2_lock, acquired in a higher layer of the V4L2
subsystem.
Reported-and-tested-by: syzbot+7fa38a608b1075dfd634@syzkaller.appspotmail.com
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: <stable@vger.kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/media/usb/usbvision/usbvision-video.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/media/usb/usbvision/usbvision-video.c b/drivers/media/usb/usbvision/usbvision-video.c index cdc66adda755..62dec73aec6e 100644 --- a/drivers/media/usb/usbvision/usbvision-video.c +++ b/drivers/media/usb/usbvision/usbvision-video.c @@ -453,6 +453,9 @@ static int vidioc_querycap(struct file *file, void *priv, { struct usb_usbvision *usbvision = video_drvdata(file); + if (!usbvision->dev) + return -ENODEV; + strscpy(vc->driver, "USBVision", sizeof(vc->driver)); strscpy(vc->card, usbvision_device_data[usbvision->dev_model].model_string, @@ -1099,8 +1102,9 @@ static int usbvision_radio_close(struct file *file) mutex_lock(&usbvision->v4l2_lock); /* Set packet size to 0 */ usbvision->iface_alt = 0; - usb_set_interface(usbvision->dev, usbvision->iface, - usbvision->iface_alt); + if (usbvision->dev) + usb_set_interface(usbvision->dev, usbvision->iface, + usbvision->iface_alt); usbvision_audio_off(usbvision); usbvision->radio = 0; |