linux-kernel - Re: [PATCH] perf: Incorrect use of snprintf results in SEGV

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20120307152848.562c72f2@wrlaptop>
Date:	Wed, 7 Mar 2012 15:28:48 -0600
From:	Peter Seebach <peter.seebach@...driver.com>
To:	Peter Zijlstra <peterz@...radead.org>
CC:	Ingo Molnar <mingo@...e.hu>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Anton Blanchard <anton@...ba.org>, <paulus@...ba.org>,
	<dsahern@...il.com>, <fweisbec@...il.com>,
	<yanmin_zhang@...ux.intel.com>, <emunson@...bm.net>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] perf: Incorrect use of snprintf results in SEGV

On Wed, 7 Mar 2012 21:59:24 +0100
Peter Zijlstra <peterz@...radead.org> wrote:

> On Wed, 2012-03-07 at 21:37 +0100, Ingo Molnar wrote:
> >         size_needed = snprintf_size(...);
> 
> This would require 3 passes over the fmt+args, first to find the
> allocated size is insufficient, 2nd to compute the size, 3rd to fill
> buffer.
> 
> Whereas with the current "creative" API only 2 passes are needed.
> 
> I can imagine that back in the day of small memory and small CPU this
> was deemed important enough.

It occurs to me that I have seen this discussion, or a variant, before:

http://coding.derkeiler.com/Archive/C_CPP/comp.lang.c/2004-11/2332.html

In which people discuss the possible alternative return values at some
length.

-s
-- 
Listen, get this.  Nobody with a good compiler needs to be justified.
--
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/