linux-kernel - Re: [PATCH] Support single byte reads from integers published in procfs by kernel/sysctl.c

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: <4F1D8F37.6020806@ixiacom.com>
Date:	Mon, 23 Jan 2012 08:47:51 -0800
From:	Earl Chew <echew@...acom.com>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
CC:	Ingo Molnar <mingo@...e.hu>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Eric Paris <eparis@...hat.com>,
	"Serge E. Hallyn" <serge.hallyn@...onical.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	<adobriyan@...il.com>
Subject: Re: [PATCH] Support single byte reads from integers published in
 procfs by kernel/sysctl.c

On 23/01/2012 8:35 AM, Eric W. Biederman wrote:
> read X < file seems like a reasonable case to support.
> Bash doesn't have that problem so presumably BusyBox is simply
> inefficient.

I think you are correct. In BusyBox, I believe there is a conscious
design decision to favour minimum size over maximum speed where it makes sense.

> If you are interested in fixing this properly with a tiny buffer
> reachable from struct file I think this can be worth fixing.  I think
> this is doable by using seq_file in proc_sys_read.

I did think about using seq_file, but my initial thoughts were that it
would end up being a much bigger change and I was reluctant to take that
on without some indication that it would be a more acceptable approach.

> Rereading different bytes of the integer multiple times when the integer
> may be changing does not seem like a reasonable implementation.

Yes. I agree with you. I shall re-work the patch as per your suggestion.

Earl

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/