tree 41304189ce140630212bfd7640d405579bf38943
parent 671632a019853744bc6c0b2ed8bcfdbcea371848
author Alan Stern <stern@rowland.harvard.edu> 1508345378 -0400
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1508346712 +0200

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

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>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>