linux-kernel - Re: Re: [PATCH] proc/sysctl: fix return error for proc_doulongvec

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] [day] [month] [year] [list]

Date:   Wed, 5 Dec 2018 15:30:48 -0800
From:   Kees Cook <keescook@...omium.org>
To:     "Luis R. Rodriguez" <mcgrof@...nel.org>, cheng.lin130@....com.cn
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        LKML <linux-kernel@...r.kernel.org>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        zhong.weidong@....com.cn, wang.yi59@....com.cn,
        Michael Kerrisk <mtk.manpages@...il.com>
Subject: Re: Re: [PATCH] proc/sysctl: fix return error for proc_doulongvec_minmax

On Mon, Dec 3, 2018 at 12:14 PM Luis Chamberlain <mcgrof@...nel.org> wrote:
> Since this worked before I do agree that we need to keep it working now,
> and I can't think of an issue with returning 0 now. Since this is about
> semantics though I'd like a bit more review from at last one more
> person.
>
> Kees, Eric, Andrew?

This is a weird one: it would return an error _AND_ still perform the
write. :( I think this patch is right, and I struggle to imagine a
case where removing the failure is a problem.

A quick question, though, do we want to instead do the reverse? (Not
update, and keep the error?) Are there any examples of doing partial
writes like this in real software?

The proposed change is the safest change, though...

-- 
Kees Cook