Openwall GNU/*/Linux - a small security-enhanced Linux distro for servers
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Sun, 25 Mar 2012 04:50:29 +0400
From: Solar Designer <solar@...nwall.com>
To: john-dev@...ts.openwall.com
Subject: Re: [JtR patch] Fast cracker for Mozilla Firefox, Thunderbird and SeaMonkey master passwords.

On Sat, Mar 24, 2012 at 01:12:53PM +0100, magnum wrote:
> On 03/24/2012 10:25 AM, Dhiru Kholia wrote:
> > However, I am getting the following warnings during compilation from
> > the DES code. Can someone take a look and fix them? Thanks!
> > 
> > mozilla_des.c: In function ?DES_CBCEn?:
> > mozilla_des.c:751:2: warning: dereferencing type-punned pointer will
> > break strict-aliasing rules [-Wstrict-aliasing]
> 
> This is more of a follow-up question than an answer :)
> 
> The enclosed patch mutes the warnings. Why are the braces needed and
> what are they "doing"? The format seem to work fine with this patch.

How did you arrive at the braces?  This is weird stuff.  I am not even
sure how to parse it (would need to do actual testing to see how gcc
treats it) - I think this may be either an array initializer or GCC's
"Statement Exprs" extension (although then you'd probably be required to
include a semicolon before the closing curly brace, so this is probably
not it).

The goal is to have correct code, not just have the warnings muted.

A correct way to deal with aliasing issues is to use a union with fields
of the desired types instead of using a typecast.

Alexander

Powered by blists - more mailing lists

Your e-mail address:

Powered by Openwall GNU/*/Linux - Powered by OpenVZ