Patch "USB: core: fix out-of-bounds access bug in usb_get_bos_descriptor()" has been added to the 4.13-stable tree

Patch "USB: core: fix out-of-bounds access bug in usb_get_bos_descriptor()" has been added to the 4.13-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    USB: core: fix out-of-bounds access bug in usb_get_bos_descriptor()

to the 4.13-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     usb-core-fix-out-of-bounds-access-bug-in-usb_get_bos_descriptor.patch
and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 1c0edc3633b56000e18d82fc241e3995ca18a69e Mon Sep 17 00:00:00 2001
From: Alan Stern <stern@rowland.harvard.edu>
Date: Wed, 18 Oct 2017 12:49:38 -0400
Subject: USB: core: fix out-of-bounds access bug in usb_get_bos_descriptor()

From: Alan Stern <stern@rowland.harvard.edu>

commit 1c0edc3633b56000e18d82fc241e3995ca18a69e upstream.

Andrey used the syzkaller fuzzer to find an out-of-bounds memory
access in usb_get_bos_descriptor().  The code wasn't checking that the
next usb_dev_cap_header structure could fit into the remaining buffer
space.

This patch fixes the error and also reduces the bNumDeviceCaps field
in the header to match the actual number of capabilities found, in
cases where there are fewer than expected.

Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/core/config.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -960,10 +960,12 @@ int usb_get_bos_descriptor(struct usb_de
 	for (i = 0; i < num; i++) {
 		buffer += length;
 		cap = (struct usb_dev_cap_header *)buffer;
-		length = cap->bLength;
 
-		if (total_len < length)
+		if (total_len < sizeof(*cap) || total_len < cap->bLength) {
+			dev->bos->desc->bNumDeviceCaps = i;
 			break;
+		}
+		length = cap->bLength;
 		total_len -= length;
 
 		if (cap->bDescriptorType != USB_DT_DEVICE_CAPABILITY) {


Patches currently in stable-queue which might be from stern@rowland.harvard.edu are

queue-4.13/usb-devio-revert-usb-devio-don-t-corrupt-user-memory.patch
queue-4.13/usb-hub-allow-reset-retry-for-usb2-devices-on-connect-bounce.patch
queue-4.13/usb-core-fix-out-of-bounds-access-bug-in-usb_get_bos_descriptor.patch
queue-4.13/usb-quirks-add-quirk-for-worlde-mini-midi-keyboard.patch