linux-kernel - Re: [bug] crash when reading /proc/mounts (was: Re: Linux 2.6.23-rc9 and a heads-up for the 2.6.24 series..)

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: <20071003154914.GA21690@elte.hu>
Date:	Wed, 3 Oct 2007 17:49:14 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Greg KH <gregkh@...e.de>,
	Alexander Viro <viro@....linux.org.uk>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: [bug] crash when reading /proc/mounts (was: Re: Linux
	2.6.23-rc9 and a heads-up for the 2.6.24 series..)


* Linus Torvalds <torvalds@...ux-foundation.org> wrote:

> Your compiler generates
> 
> 	movl    -16(%ebp),%edx
> 	movl    (%edx),%edi		/* this is _totally_ bogus! */
> 	incl    %edx
> 	movl    %edx,-16(%ebp)
> 	movl    %edi,%ecx
> 	testb   %cl,%cl
> 	je      ...

ah, ok.

> while I get (gcc version 4.1.2 20070925 (Red Hat 4.1.2-28)):
> 
>         movl    -16(%ebp), %eax # p,
>         movzbl  (%eax), %edi    #, c	/* not bogus! */
>         movl    %edi, %edx      # c,
>         testb   %dl, %dl        #
>         je      .L64    #,
>         incl    %eax    #
>         movsbl  %dl,%ebx        #, D.12414
>         movl    %eax, -16(%ebp) #, p
> 
> where the difference (apart from doing the increment differently and 
> different register allocation) is that I have a "movzbl" (correct), 
> while you have a "movl" (pure and utter crap).

i'll try with another compiler in a minute.

	Ingo
-
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/