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Commit a43bb9e8 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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USB: Fix slab-out-of-bounds write in usb_get_bos_descriptor 



commit a03ff54460817c76105f81f3aa8ef655759ccc9a upstream.

The syzkaller USB fuzzer found a slab-out-of-bounds write bug in the
USB core, caused by a failure to check the actual size of a BOS
descriptor.  This patch adds a check to make sure the descriptor is at
least as large as it is supposed to be, so that the code doesn't
inadvertently access memory beyond the end of the allocated region
when assigning to dev->bos->desc->bNumDeviceCaps later on.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: default avatar <syzbot+71f1e64501a309fcc012@syzkaller.appspotmail.com>
CC: <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2fc485b0

drivers/usb/core/config.c

+2 −2
Original line number Diff line number Diff line
@@ -936,8 +936,8 @@ int usb_get_bos_descriptor(struct usb_device *dev) 


	/* Get BOS descriptor */

	ret = usb_get_descriptor(dev, USB_DT_BOS, 0, bos, USB_DT_BOS_SIZE);

	if (ret < USB_DT_BOS_SIZE) {

		dev_err(ddev, "unable to get BOS descriptor\n");

	if (ret < USB_DT_BOS_SIZE || bos->bLength < USB_DT_BOS_SIZE) {

		dev_err(ddev, "unable to get BOS descriptor or descriptor too short\n");

		if (ret >= 0)

			ret = -ENOMSG;

		kfree(bos);