linux-kernel - Re: [PATCH] usercopy: add testcases to check zeroing on failure of usercopy

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAGXu5j+iJ2nGoqok7deER_QnedPFjZ5Qb+ja4VnkPqnNL=vTcg@mail.gmail.com>
Date:   Mon, 13 Feb 2017 10:21:13 -0800
From:   Kees Cook <keescook@...omium.org>
To:     Hoeun Ryu <hoeun.ryu@...il.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        "kernel-hardening@...ts.openwall.com" 
        <kernel-hardening@...ts.openwall.com>
Subject: Re: [PATCH] usercopy: add testcases to check zeroing on failure of usercopy

On Sat, Feb 11, 2017 at 10:13 PM, Hoeun Ryu <hoeun.ryu@...il.com> wrote:
> In the hardend usercopy, the destination buffer will be zeroed if
> copy_from_user/get_user fails. This patch adds testcases for it.
> The destination buffer is set with non-zero value before illegal
> copy_from_user/get_user is executed and the buffer is compared to
> zero after usercopy is done.
>
> Signed-off-by: Hoeun Ryu <hoeun.ryu@...il.com>

This looks great!

I'll adjust the commit slightly (the zeroing always happens,
regardless of hardened usercopy) and add it to my usercopy tree.

Thanks!

-Kees

-- 
Kees Cook
Pixel Security