Re: [PATCH net v2] r8152: check the informaton of the device

[Greg KH <gregkh@linuxfoundation.org>]

On Sat, May 22, 2021 at 01:24:54PM +0800, Hayes Wang wrote:
> Verify some fields of the USB descriptor to make sure the driver
> could be used by the device.
> 
> Besides, remove the check of endpoint number in rtl8152_probe().
> It has been done in rtl_check_vendor_ok().
> 
> BugLink: https://syzkaller.appspot.com/bug?id=912c9c373656996801b4de61f1e3cb326fe940aa
> Reported-by: syzbot+95afd23673f5dd295c57@syzkaller.appspotmail.com
> Fixes: c2198943e33b ("r8152: search the configuration of vendor mode")
> Signed-off-by: Hayes Wang <hayeswang@realtek.com>
> ---
> v2:
> Use usb_find_common_endpoints() and usb_endpoint_num() to replace original
> code.

Much better, just some tiny grammer changes below:

> 
> remove the check of endpoint number in rtl8152_probe(). It has been done
> in rtl_check_vendor_ok().
> 
>  drivers/net/usb/r8152.c | 44 ++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 39 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
> index 136ea06540ff..6e5230d6c721 100644
> --- a/drivers/net/usb/r8152.c
> +++ b/drivers/net/usb/r8152.c
> @@ -8107,6 +8107,39 @@ static void r8156b_init(struct r8152 *tp)
>  	tp->coalesce = 15000;	/* 15 us */
>  }
>  
> +static bool rtl_check_vendor_ok(struct usb_interface *intf)
> +{
> +	struct usb_host_interface *alt = intf->cur_altsetting;
> +	struct usb_endpoint_descriptor *in, *out, *intr;
> +
> +	if (alt->desc.bNumEndpoints < 3) {
> +		dev_err(&intf->dev, "Unexpected bNumEndpoints %d\n", alt->desc.bNumEndpoints);
> +		return false;
> +	}
> +
> +	if (usb_find_common_endpoints(alt, &in, &out, &intr, NULL) < 0) {
> +		dev_err(&intf->dev, "Miss Endpoints\n");

"Miss" feels ackward, how about "Invalid number of endpoints"?

> +		return false;
> +	}
> +
> +	if (usb_endpoint_num(in) != 1) {
> +		dev_err(&intf->dev, "Invalid Rx Endpoint\n");

"Invalid number of Rx endpoints"

> +		return false;
> +	}
> +
> +	if (usb_endpoint_num(out) != 2) {
> +		dev_err(&intf->dev, "Invalid Tx Endpoint\n");

"Invalid number of RX endpoints"

> +		return false;
> +	}
> +
> +	if (usb_endpoint_num(intr) != 3) {
> +		dev_err(&intf->dev, "Invalid interrupt Endpoint\n");

"Invalid number of interrupt endpoints"

But really, this doesn't matter, all is good if you don't want to change
this :)

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>