USB: core: prevent malicious bNumInterfaces overflow

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commit 48a4ff1c7b upstream.

A malicious USB device with crafted descriptors can cause the kernel
to access unallocated memory by setting the bNumInterfaces value too
high in a configuration descriptor.  Although the value is adjusted
during parsing, this adjustment is skipped in one of the error return
paths.

This patch prevents the problem by setting bNumInterfaces to 0
initially.  The existing code already sets it to the proper value
after parsing is complete.

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

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Alan Stern 2017-12-12 14:25:13 -05:00 • committed by Greg Kroah-Hartman

parent 6391294874

commit 4c5ae6a301

1 changed files with 3 additions and 1 deletions

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drivers/usb/core/config.c

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