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Date:   Sat, 14 May 2022 15:32:27 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Zheyu Ma <zheyuma97@gmail.com>
Cc:     eli.billauer@gmail.com, arnd@arndb.de, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] char: xillybus: Check endpoint type before allocing
Message-ID: <Yn+va5fTsuaFTxVR@kroah.com>
References: <Yn9XwHxWsLIJXlHu@kroah.com>
 <20220514114819.2773691-1-zheyuma97@gmail.com>
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On Sat, May 14, 2022 at 07:48:19PM +0800, Zheyu Ma wrote:
> The driver submits bulk urb without checking the endpoint type is
> actually bulk.
> 
> [    3.108690] usb 1-1: BOGUS urb xfer, pipe 3 != type 1
> [    3.108983] WARNING: CPU: 0 PID: 211 at drivers/usb/core/urb.c:503 usb_submit_urb+0xcd9/0x18b0
> [    3.110976] RIP: 0010:usb_submit_urb+0xcd9/0x18b0
> [    3.115318] Call Trace:
> [    3.115452]  <TASK>
> [    3.115570]  try_queue_bulk_in+0x43c/0x6e0 [xillyusb]
> [    3.115838]  xillyusb_probe+0x488/0x1230 [xillyusb]
> 
> Add a check in endpoint_alloc() to fix the bug.
> 
> Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
> ---
> Changes in v2:
>     - Check the endpoint type at probe time
> ---
>  drivers/char/xillybus/xillyusb.c | 27 ++++++++++++++++++++++++++-
>  1 file changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/char/xillybus/xillyusb.c b/drivers/char/xillybus/xillyusb.c
> index dc3551796e5e..4467f13993ef 100644
> --- a/drivers/char/xillybus/xillyusb.c
> +++ b/drivers/char/xillybus/xillyusb.c
> @@ -167,6 +167,7 @@ struct xillyusb_dev {
>  	struct device		*dev; /* For dev_err() and such */
>  	struct kref		kref;
>  	struct workqueue_struct	*workq;
> +	struct usb_interface *intf;
>  
>  	int error;
>  	spinlock_t error_lock; /* protect @error */
> @@ -475,6 +476,25 @@ static void endpoint_dealloc(struct xillyusb_endpoint *ep)
>  	kfree(ep);
>  }
>  
> +static int xillyusb_check_endpoint(struct xillyusb_dev *xdev, u8 ep_num)
> +{
> +	struct usb_host_interface *if_desc = xdev->intf->altsetting;
> +	int i;
> +
> +	for (i = 0; i < if_desc->desc.bNumEndpoints; i++) {
> +		struct usb_endpoint_descriptor *ep = &if_desc->endpoint[i].desc;
> +
> +		if (ep->bEndpointAddress != ep_num)
> +			continue;
> +
> +		if ((usb_pipein(ep_num) && usb_endpoint_is_bulk_in(ep)) ||
> +			(usb_pipeout(ep_num) && usb_endpoint_is_bulk_out(ep)))
> +			return 0;
> +	}

Why not use the built-in usb core functions that do this for you instead
of hand-parsing this?  Look at usb_find_common_endpoints() and related
functions, that should make this much easier.

thanks,

greg k-h