USB: core: prevent malicious bNumInterfaces overflow

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 <[email protected]>
Reported-by: Andrey Konovalov <[email protected]>
CC: <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

0 files changed, 0 insertions, 0 deletions