From 7d21e0b1b41b21d628bf2afce777727bd4479aa5 Mon Sep 17 00:00:00 2001 From: Shigeru Yoshida Date: Wed, 23 Nov 2022 03:51:59 +0900 Subject: media: si470x: Fix use-after-free in si470x_int_in_callback() 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@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=94ed6dddd5a55e90fd4bab942aa4bb297741d977 [1] Signed-off-by: Shigeru Yoshida Signed-off-by: Hans Verkuil --- drivers/media/radio/si470x/radio-si470x-usb.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/media') diff --git a/drivers/media/radio/si470x/radio-si470x-usb.c b/drivers/media/radio/si470x/radio-si470x-usb.c index 6b2768623c88..aa7a580dbecc 100644 --- a/drivers/media/radio/si470x/radio-si470x-usb.c +++ b/drivers/media/radio/si470x/radio-si470x-usb.c @@ -727,8 +727,10 @@ 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 */ -- cgit v1.2.3