linux-kernel - Re: [PATCH v2] selinux: check for address length in selinux_socket

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Date:   Fri, 10 Mar 2017 07:01:47 -0500
From:   Paul Moore <paul@...l-moore.com>
To:     David Miller <davem@...emloft.net>,
        Stephen Smalley <sds@...ho.nsa.gov>
Cc:     glider@...gle.com, dvyukov@...gle.com, kcc@...gle.com,
        keescook@...omium.org, edumazet@...gle.com,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        selinux@...ho.nsa.gov
Subject: Re: [PATCH v2] selinux: check for address length in selinux_socket_bind()

On Thu, Mar 9, 2017 at 2:12 AM, David Miller <davem@...emloft.net> wrote:
> From: Alexander Potapenko <glider@...gle.com>
> Date: Mon,  6 Mar 2017 19:46:14 +0100
>
>> KMSAN (KernelMemorySanitizer, a new error detection tool) reports use of
>> uninitialized memory in selinux_socket_bind():
>  ...
>> (the line numbers are relative to 4.8-rc6, but the bug persists upstream)
>>
>> , when I run the following program as root:
>  ...
>> (for different values of |size| other error reports are printed).
>>
>> This happens because bind() unconditionally copies |size| bytes of
>> |addr| to the kernel, leaving the rest uninitialized. Then
>> security_socket_bind() reads the IP address bytes, including the
>> uninitialized ones, to determine the port, or e.g. pass them further to
>> sel_netnode_find(), which uses them to calculate a hash.
>>
>> Signed-off-by: Alexander Potapenko <glider@...gle.com>
>
> Are the SELINUX folks going to pick this up or should I?

Yes, it's on my list of things to merge, I was just a bit distracted
this week with yet another audit problem.  I'm going to start making
my way through the patch backlog today.

-- 
paul moore
www.paul-moore.com