Re: [PATCH 1/2] usb: core: config: fix validation of wMaxPacketValue entries

Alan Stern
2021-12-10T15:49:10Z

On Fri, Dec 10, 2021 at 09:52:18AM +0100, Pavel Hofman wrote:
> The checks performed by commit aed9d65ac327 ("USB: validate
> wMaxPacketValue entries in endpoint descriptors") require that initial
> value of the maxp variable contains both maximum packet size bits
> (10..0) and multiple-transactions bits (12..11). However, the existing
> code assings only the maximum packet size bits. This patch assigns all
> bits of wMaxPacketSize to the variable.
>
> Fixes: aed9d65ac327 ("USB: validate wMaxPacketValue entries in endpoint descriptors")
> Signed-off-by: Pavel Hofman <pavel.hofman@ivitera.com>
> ---

Acked-by: Alan Stern <stern@rowland.harvard.edu>

This should have a "CC: <stable@vger.kernel.org>" tag attached.

> drivers/usb/core/config.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
> index b199eb65f378..74eb356c8767 100644
> --- a/drivers/usb/core/config.c
> +++ b/drivers/usb/core/config.c
> @@ -406,7 +406,7 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno,
> * the USB-2 spec requires such endpoints to have wMaxPacketSize = 0
> * (see the end of section 5.6.3), so don't warn about them.
> */
> - maxp = usb_endpoint_maxp(&endpoint->desc);
> + maxp = le16_to_cpu(endpoint->desc.wMaxPacketSize);
> if (maxp == 0 && !(usb_endpoint_xfer_isoc(d) && asnum == 0)) {
> dev_warn(ddev, "config %d interface %d altsetting %d endpoint 0x%X has invalid wMaxPacketSize 0\n",
> cfgno, inum, asnum, d->bEndpointAddress);
> --
> 2.25.1
>