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Message-ID: <1574850465.2485.10.camel@suse.com>
Date: Wed, 27 Nov 2019 11:27:45 +0100
From: Oliver Neukum <oneukum@...e.com>
To: syzbot <syzbot+9ca7a12fd736d93e0232@...kaller.appspotmail.com>,
andreyknvl@...gle.com, hverkuil@...all.nl,
linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
linux-usb@...r.kernel.org, mchehab@...nel.org,
syzkaller-bugs@...glegroups.com
Subject: Re: KASAN: use-after-free Read in si470x_int_in_callback (2)
Am Freitag, den 18.10.2019, 07:53 -0700 schrieb syzbot:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 22be26f7 usb-fuzzer: main usb gadget fuzzer driver
> git tree: https://github.com/google/kasan.git usb-fuzzer
> console output: https://syzkaller.appspot.com/x/log.txt?x=102b65cf600000
> kernel config: https://syzkaller.appspot.com/x/.config?x=387eccb7ac68ec5
> dashboard link: https://syzkaller.appspot.com/bug?extid=9ca7a12fd736d93e0232
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=143b9060e00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15d3b94b600000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+9ca7a12fd736d93e0232@...kaller.appspotmail.com
#syz test: https://github.com/google/kasan.git 22be26f7
>From 497dce10b022c0cfbba450a47d634aa212ecafa1 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@...e.com>
Date: Mon, 18 Nov 2019 14:41:51 +0100
Subject: [PATCH] si470x: prevent resubmission
Starting IO to a device is not necessarily a NOP in every error
case. So we need to terminate all IO in every case of probe
failure and disconnect with absolute certainty.
Signed-off-by: Oliver Neukum <oneukum@...e.com>
---
drivers/media/radio/si470x/radio-si470x-usb.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/media/radio/si470x/radio-si470x-usb.c b/drivers/media/radio/si470x/radio-si470x-usb.c
index fedff68d8c49..8663828d93a5 100644
--- a/drivers/media/radio/si470x/radio-si470x-usb.c
+++ b/drivers/media/radio/si470x/radio-si470x-usb.c
@@ -542,6 +542,8 @@ static int si470x_start_usb(struct si470x_device *radio)
radio->int_in_running = 0;
}
radio->status_rssi_auto_update = radio->int_in_running;
+ if (retval < 0)
+ return retval;
/* start radio */
retval = si470x_start(radio);
@@ -734,7 +736,8 @@ static int si470x_usb_driver_probe(struct usb_interface *intf,
/* start radio */
retval = si470x_start_usb(radio);
if (retval < 0)
- goto err_buf;
+ /* the urb may be running even after an error */
+ goto err_all;
/* set initial frequency */
si470x_set_freq(radio, 87.5 * FREQ_MUL); /* available in all regions */
@@ -749,7 +752,7 @@ static int si470x_usb_driver_probe(struct usb_interface *intf,
return 0;
err_all:
- usb_kill_urb(radio->int_in_urb);
+ usb_poison_urb(radio->int_in_urb);
err_buf:
kfree(radio->buffer);
err_ctrl:
@@ -824,7 +827,7 @@ static void si470x_usb_driver_disconnect(struct usb_interface *intf)
mutex_lock(&radio->lock);
v4l2_device_disconnect(&radio->v4l2_dev);
video_unregister_device(&radio->videodev);
- usb_kill_urb(radio->int_in_urb);
+ usb_poison_urb(radio->int_in_urb);
usb_set_intfdata(intf, NULL);
mutex_unlock(&radio->lock);
v4l2_device_put(&radio->v4l2_dev);
--
2.16.4
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