[PATCH 4.9 31/42] usb: core: config: fix validation of wMaxPacketValue entries

[Greg Kroah-Hartman]

From: Pavel Hofman <pavel.hofman@xxxxxxxxxxx>

commit 1a3910c80966e4a76b25ce812f6bea0ef1b1d530 upstream.

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")
Cc: stable <stable@xxxxxxxxxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Pavel Hofman <pavel.hofman@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20211210085219.16796-1-pavel.hofman@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/usb/core/config.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -404,7 +404,7 @@ static int usb_parse_endpoint(struct dev
 	 * 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);