diff options
| author | Jeongjun Park <aha310510@gmail.com> | 2026-01-10 17:58:29 +0300 |
|---|---|---|
| committer | Hans Verkuil <hverkuil+cisco@kernel.org> | 2026-03-17 12:50:18 +0300 |
| commit | 3b7da2b4d0fe014eff181ed37e3bf832eb8ed258 (patch) | |
| tree | b6e55a5ef3dbe74931e78dfc7aa22453393aa730 /drivers | |
| parent | bb2a3912549d3b5cef5ed27200402fe8f6fb0694 (diff) | |
| download | linux-3b7da2b4d0fe014eff181ed37e3bf832eb8ed258.tar.xz | |
media: hackrf: fix to not free memory after the device is registered in hackrf_probe()
In hackrf driver, the following race condition occurs:
```
CPU0 CPU1
hackrf_probe()
kzalloc(); // alloc hackrf_dev
....
v4l2_device_register();
....
fd = sys_open("/path/to/dev"); // open hackrf fd
....
v4l2_device_unregister();
....
kfree(); // free hackrf_dev
....
sys_ioctl(fd, ...);
v4l2_ioctl();
video_is_registered() // UAF!!
....
sys_close(fd);
v4l2_release() // UAF!!
hackrf_video_release()
kfree(); // DFB!!
```
When a V4L2 or video device is unregistered, the device node is removed so
new open() calls are blocked.
However, file descriptors that are already open-and any in-flight I/O-do
not terminate immediately; they remain valid until the last reference is
dropped and the driver's release() is invoked.
Therefore, freeing device memory on the error path after hackrf_probe()
has registered dev it will lead to a race to use-after-free vuln, since
those already-open handles haven't been released yet.
And since release() free memory too, race to use-after-free and
double-free vuln occur.
To prevent this, if device is registered from probe(), it should be
modified to free memory only through release() rather than calling
kfree() directly.
Cc: <stable@vger.kernel.org>
Reported-by: syzbot+6ffd76b5405c006a46b7@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=6ffd76b5405c006a46b7
Reported-by: syzbot+f1b20958f93d2d250727@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=f1b20958f93d2d250727
Fixes: 8bc4a9ed8504 ("[media] hackrf: add support for transmitter")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/media/usb/hackrf/hackrf.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/media/usb/hackrf/hackrf.c b/drivers/media/usb/hackrf/hackrf.c index 94d356fba612..a15829a60e88 100644 --- a/drivers/media/usb/hackrf/hackrf.c +++ b/drivers/media/usb/hackrf/hackrf.c @@ -1485,7 +1485,7 @@ static int hackrf_probe(struct usb_interface *intf, if (ret) { dev_err(dev->dev, "Failed to register as video device (%d)\n", ret); - goto err_v4l2_device_unregister; + goto err_v4l2_device_put; } dev_info(dev->dev, "Registered as %s\n", video_device_node_name(&dev->rx_vdev)); @@ -1513,8 +1513,9 @@ static int hackrf_probe(struct usb_interface *intf, return 0; err_video_unregister_device_rx: video_unregister_device(&dev->rx_vdev); -err_v4l2_device_unregister: - v4l2_device_unregister(&dev->v4l2_dev); +err_v4l2_device_put: + v4l2_device_put(&dev->v4l2_dev); + return ret; err_v4l2_ctrl_handler_free_tx: v4l2_ctrl_handler_free(&dev->tx_ctrl_handler); err_v4l2_ctrl_handler_free_rx: |