[Linux-kernel-mentees] [PATCH v3] Media: Radio: Change devm_k*alloc to k*alloc
Greg KH
gregkh at linuxfoundation.org
Tue Jun 18 06:10:01 UTC 2019
On Mon, Jun 17, 2019 at 10:42:49PM -0700, Luke Nowakowski-Krijger wrote:
> Change devm_k*alloc to k*alloc to manually allocate memory. Memory is freed in v4l2.release callback which now calls raremono_device_release to free up the appropriate memory, just like in radio-shark driver.
Please properly wrap your changelog text at 72 columns and do not add
trailing whitespace.
>
> This patch aims to fix the use-after-free read described in
> https://syzkaller.appspot.com/bug?extid=a4387f5b6b799f6becbf
Does it? Did you submit it to syzkaller and get any results?
There is a proper way to credit the tool as well, please do that.
>
> Signed-off-by: Luke Nowakowski-Krijger <lnowakow at eng.ucsd.edu>
> ---
> diff --git a/drivers/media/radio/radio-raremono.c b/drivers/media/radio/radio-raremono.c
> index 5e782b3c2fa9..b467ad7fdd21 100644
> --- a/drivers/media/radio/radio-raremono.c
> +++ b/drivers/media/radio/radio-raremono.c
> @@ -271,6 +271,15 @@ static int vidioc_g_frequency(struct file *file, void *priv,
> return 0;
> }
>
> +static void raremono_device_release(struct v4l2_device *v4l2_dev)
> +{
> + struct raremono_device *radio = to_raremono_dev(v4l2_dev);
> +
Trailing whitespace :(
Did you run your patch through checkpatch?
> + kfree(radio->buffer);
> + kfree(radio);
> +}
> +
> +
> /* File system interface */
> static const struct v4l2_file_operations usb_raremono_fops = {
> .owner = THIS_MODULE,
> @@ -295,12 +304,15 @@ static int usb_raremono_probe(struct usb_interface *intf,
> struct raremono_device *radio;
> int retval = 0;
>
> - radio = devm_kzalloc(&intf->dev, sizeof(struct raremono_device), GFP_KERNEL);
> - if (radio)
> - radio->buffer = devm_kmalloc(&intf->dev, BUFFER_LENGTH, GFP_KERNEL);
> -
> - if (!radio || !radio->buffer)
> + radio = kzalloc(sizeof(struct raremono_device), GFP_KERNEL);
> + if (!radio)
> return -ENOMEM;
> +
Trailing whitespace :(
> + radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);
> + if (!radio->buffer) {
> + kfree(radio);
> + return -ENOMEM;
> + }
>
> radio->usbdev = interface_to_usbdev(intf);
> radio->intf = intf;
> @@ -324,7 +336,9 @@ static int usb_raremono_probe(struct usb_interface *intf,
> if (retval != 3 ||
> (get_unaligned_be16(&radio->buffer[1]) & 0xfff) == 0x0242) {
> dev_info(&intf->dev, "this is not Thanko's Raremono.\n");
> - return -ENODEV;
> +
More trailing whitespace.
Please fix your editor to show this type of thing in bright red so you
know not to include it. It's all over this patch.
thanks.
greg k-h
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