This is a note to let you know that I've just added the patch titled media: si470x: Fix use-after-free in si470x_int_in_callback() to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: media-si470x-fix-use-after-free-in-si470x_int_in_cal.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 887dcd0049da53d3dca9aa5454e5e59459130913 Author: Shigeru Yoshida <syoshida@xxxxxxxxxx> Date: Wed Nov 23 03:51:59 2022 +0900 media: si470x: Fix use-after-free in si470x_int_in_callback() [ Upstream commit 7d21e0b1b41b21d628bf2afce777727bd4479aa5 ] syzbot reported use-after-free in si470x_int_in_callback() [1]. This indicates that urb->context, which contains struct si470x_device object, is freed when si470x_int_in_callback() is called. The cause of this issue is that si470x_int_in_callback() is called for freed urb. si470x_usb_driver_probe() calls si470x_start_usb(), which then calls usb_submit_urb() and si470x_start(). If si470x_start_usb() fails, si470x_usb_driver_probe() doesn't kill urb, but it just frees struct si470x_device object, as depicted below: si470x_usb_driver_probe() ... si470x_start_usb() ... usb_submit_urb() retval = si470x_start() return retval if (retval < 0) free struct si470x_device object, but don't kill urb This patch fixes this issue by killing urb when si470x_start_usb() fails and urb is submitted. If si470x_start_usb() fails and urb is not submitted, i.e. submitting usb fails, it just frees struct si470x_device object. Reported-by: syzbot+9ca7a12fd736d93e0232@xxxxxxxxxxxxxxxxxxxxxxxxx Link: https://syzkaller.appspot.com/bug?id=94ed6dddd5a55e90fd4bab942aa4bb297741d977 [1] Signed-off-by: Shigeru Yoshida <syoshida@xxxxxxxxxx> Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/media/radio/si470x/radio-si470x-usb.c b/drivers/media/radio/si470x/radio-si470x-usb.c index 3f8634a46573..1365ae732b79 100644 --- a/drivers/media/radio/si470x/radio-si470x-usb.c +++ b/drivers/media/radio/si470x/radio-si470x-usb.c @@ -733,8 +733,10 @@ static int si470x_usb_driver_probe(struct usb_interface *intf, /* start radio */ retval = si470x_start_usb(radio); - if (retval < 0) + if (retval < 0 && !radio->int_in_running) goto err_buf; + else if (retval < 0) /* in case of radio->int_in_running == 1 */ + goto err_all; /* set initial frequency */ si470x_set_freq(radio, 87.5 * FREQ_MUL); /* available in all regions */