USB: Fix off by one in type-specific length check of BOS SSP capability

USB 3.1 devices are not detected as 3.1 capable since 4.15-rc3 due to a
off by one in commit 81cf4a4536 ("USB: core: Add type-specific length
check of BOS descriptors")

It uses USB_DT_USB_SSP_CAP_SIZE() to get SSP capability size which takes
the zero based SSAC as argument, not the actual count of sublink speed
attributes.

USB3 spec 9.6.2.5 says "The number of Sublink Speed Attributes = SSAC + 1."

The type-specific length check patch was added to stable and needs to be
fixed there as well

Fixes: 81cf4a4536 ("USB: core: Add type-specific length check of BOS descriptors")
Cc: linux-stable <stable@vger.kernel.org>
CC: Masakazu Mokuno <masakazu.mokuno@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mathias Nyman 2017-12-19 11:14:42 +02:00 committed by Greg Kroah-Hartman
parent 6074bc0c85
commit 07b9f12864
1 changed files with 1 additions and 1 deletions

View File

@ -1007,7 +1007,7 @@ int usb_get_bos_descriptor(struct usb_device *dev)
case USB_SSP_CAP_TYPE:
ssp_cap = (struct usb_ssp_cap_descriptor *)buffer;
ssac = (le32_to_cpu(ssp_cap->bmAttributes) &
USB_SSP_SUBLINK_SPEED_ATTRIBS) + 1;
USB_SSP_SUBLINK_SPEED_ATTRIBS);
if (length >= USB_DT_USB_SSP_CAP_SIZE(ssac))
dev->bos->ssp_cap = ssp_cap;
break;