USB: devio: Prevent integer overflow in proc_do_submiturb()

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commit 57999d1107 upstream.

There used to be an integer overflow check in proc_do_submiturb() but
we removed it.  It turns out that it's still required.  The
uurb->buffer_length variable is a signed integer and it's controlled by
the user.  It can lead to an integer overflow when we do:

	num_sgs = DIV_ROUND_UP(uurb->buffer_length, USB_SG_SIZE);

If we strip away the macro then that line looks like this:

	num_sgs = (uurb->buffer_length + USB_SG_SIZE - 1) / USB_SG_SIZE;
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
It's the first addition which can overflow.

Fixes: 1129d270cb ("USB: Increase usbfs transfer limit")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Dan Carpenter 2017-09-22 23:43:25 +03:00 • committed by Greg Kroah-Hartman

parent d6ab871c43

commit 545c103753

1 changed files with 5 additions and 0 deletions

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drivers/usb/core/devio.c

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