Re: [PATCH 4.5 058/238] USB: iowarrior: fix oops with malicious USB descriptors

From	Ben Hutchings <ben@decadent.org.uk>
Newsgroups	linux.kernel
Subject	Re: [PATCH 4.5 058/238] USB: iowarrior: fix oops with malicious USB descriptors
Date	2016-04-12 03:40 +0200
Message-ID	<rmVt9-7gi-17@gated-at.bofh.it> (permalink)
References	<rmsr7-Nr-3@gated-at.bofh.it> <rmsAO-Sh-39@gated-at.bofh.it>
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On Sun, 2016-04-10 at 11:33 -0700, Greg Kroah-Hartman wrote:

> 4.5-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Josh Boyer <jwboyer@fedoraproject.org>
> 
> commit 4ec0ef3a82125efc36173062a50624550a900ae0 upstream.
> 
> The iowarrior driver expects at least one valid endpoint.  If given
> malicious descriptors that specify 0 for the number of endpoints,
> it will crash in the probe function.  Ensure there is at least
> one endpoint on the interface before using it.
[...]

Which means our imaginary attacker will move on to providing a single
endpoint of the wrong type.  You've fixed the driver to reject the PoC
descriptor without thinking about what the driver actually requires.

I don't see the point of applying this to stable; it doesn't provide
any meaningful security benefit.

Ben.

-- 
Ben Hutchings
This sentence contradicts itself - no actually it doesn't.

Thread

[PATCH 4.5 058/238] USB: iowarrior: fix oops with malicious USB descriptors Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 20:50 +0200
  Re: [PATCH 4.5 058/238] USB: iowarrior: fix oops with malicious USB  descriptors Ben Hutchings <ben@decadent.org.uk> - 2016-04-12 03:40 +0200
    Re: [PATCH 4.5 058/238] USB: iowarrior: fix oops with malicious USB  descriptors Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-12 16:30 +0200

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