[net,stable] net: cdc_ncm: GetNtbFormat endian fix

The GetNtbFormat and SetNtbFormat requests operate on 16 bit little
endian values. We get away with ignoring this most of the time, because
we only care about USB_CDC_NCM_NTB16_FORMAT which is 0x0000.  This
fails for USB_CDC_NCM_NTB32_FORMAT.

Fix comparison between LE value from device and constant by converting
the constant to LE.

Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Fixes: 2b02c20ce0c2 ("cdc_ncm: Set NTB format again after altsetting switch for Huawei devices")
Cc: Enrico Mioso <mrkiko.rs@gmail.com>
Cc: Christian Panton <christian@panton.org>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
---
 drivers/net/usb/cdc_ncm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Thank you very much Ben and bjorn, for the spot, the fix, and overall helping me learn new things.

Acked-By: Enrico Mioso <mrkiko.rs@gmail.com>



On Wed, 15 Nov 2017, Bjørn Mork wrote:

> Date: Wed, 15 Nov 2017 09:35:02
> From: Bjørn Mork <bjorn@mork.no>
> To: netdev@vger.kernel.org
> Cc: Oliver Neukum <oliver@neukum.org>,
>     Ben Hutchings <ben.hutchings@codethink.co.uk>, linux-usb@vger.kernel.org,
>     Bjørn Mork <bjorn@mork.no>, Enrico Mioso <mrkiko.rs@gmail.com>,
>     Christian Panton <christian@panton.org>
> Subject: [PATCH net,stable] net: cdc_ncm: GetNtbFormat endian fix
> 
> The GetNtbFormat and SetNtbFormat requests operate on 16 bit little
> endian values. We get away with ignoring this most of the time, because
> we only care about USB_CDC_NCM_NTB16_FORMAT which is 0x0000.  This
> fails for USB_CDC_NCM_NTB32_FORMAT.
>
> Fix comparison between LE value from device and constant by converting
> the constant to LE.
>
> Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
> Fixes: 2b02c20ce0c2 ("cdc_ncm: Set NTB format again after altsetting switch for Huawei devices")
> Cc: Enrico Mioso <mrkiko.rs@gmail.com>
> Cc: Christian Panton <christian@panton.org>
> Signed-off-by: Bjørn Mork <bjorn@mork.no>
> ---
> drivers/net/usb/cdc_ncm.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
> index 47cab1bde065..9e1b74590682 100644
> --- a/drivers/net/usb/cdc_ncm.c
> +++ b/drivers/net/usb/cdc_ncm.c
> @@ -771,7 +771,7 @@ int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_
> 	int err;
> 	u8 iface_no;
> 	struct usb_cdc_parsed_header hdr;
> -	u16 curr_ntb_format;
> +	__le16 curr_ntb_format;
>
> 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> 	if (!ctx)
> @@ -889,7 +889,7 @@ int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_
> 			goto error2;
> 		}
>
> -		if (curr_ntb_format == USB_CDC_NCM_NTB32_FORMAT) {
> +		if (curr_ntb_format == cpu_to_le16(USB_CDC_NCM_NTB32_FORMAT)) {
> 			dev_info(&intf->dev, "resetting NTB format to 16-bit");
> 			err = usbnet_write_cmd(dev, USB_CDC_SET_NTB_FORMAT,
> 					       USB_TYPE_CLASS | USB_DIR_OUT
> -- 
> 2.11.0
>
>

From: Bjørn Mork <bjorn@mork.no>
Date: Wed, 15 Nov 2017 09:35:02 +0100

> The GetNtbFormat and SetNtbFormat requests operate on 16 bit little
> endian values. We get away with ignoring this most of the time, because
> we only care about USB_CDC_NCM_NTB16_FORMAT which is 0x0000.  This
> fails for USB_CDC_NCM_NTB32_FORMAT.
> 
> Fix comparison between LE value from device and constant by converting
> the constant to LE.
> 
> Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
> Fixes: 2b02c20ce0c2 ("cdc_ncm: Set NTB format again after altsetting switch for Huawei devices")
> Cc: Enrico Mioso <mrkiko.rs@gmail.com>
> Cc: Christian Panton <christian@panton.org>
> Signed-off-by: Bjørn Mork <bjorn@mork.no>

Applied and queued up for -stable, thanks.