From: Shigeru Yoshida Date: Tue, 22 Nov 2022 18:51:59 +0000 (+0900) Subject: media: si470x: Fix use-after-free in si470x_int_in_callback() X-Git-Tag: v6.6.17~5419^2~84^2~4 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7d21e0b1b41b21d628bf2afce777727bd4479aa5;p=platform%2Fkernel%2Flinux-rpi.git 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 --- diff --git a/drivers/media/radio/si470x/radio-si470x-usb.c b/drivers/media/radio/si470x/radio-si470x-usb.c index 6b27686..aa7a580 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 */