linux-kernel - Re: [PATCH] diskquota: 32bit quota tools on 64bit architectures

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]

Message-Id: <1182152472.4052.2.camel@dhcp0-248.sw.ru>
Date:	Mon, 18 Jun 2007 11:41:12 +0400
From:	Vasily Tarasov <vtaras@...nvz.org>
To:	Arnd Bergmann <arnd@...db.de>
Cc:	Mikael Pettersson <mikpe@...uu.se>, akpm@...ux-foundation.org,
	dev@...ru, devel@...nvz.org, jack@...e.cz,
	linux-kernel@...r.kernel.org, nataliep@...gle.com, vvs@...ru
Subject: Re: [PATCH] diskquota: 32bit quota tools on 64bit architectures

On Fri, 2007-06-15 at 17:24 +0200, Arnd Bergmann wrote:
> On Friday 15 June 2007, Vasily Tarasov wrote:
> > I just noticed that we can not avoid the addition of packed attribute.
> > Look, for example:
> > 
> > struct if_dqblk {
> >         __u64 dqb_bhardlimit; 
> >         __u64 dqb_bsoftlimit;
> >         __u64 dqb_curspace;
> >         __u64 dqb_ihardlimit;
> >         __u64 dqb_isoftlimit;
> >         __u64 dqb_curinodes; 
> >         __u64 dqb_btime;
> >         __u64 dqb_itime;
> >         __u32 dqb_valid;
> > };
> > 
> > sizeof(if_dqblk) = 0x48
> > On 32 bit: 0x44
> > 
> > If I replace __u64/__u32 with compat equivalents - it will not help!
> > alligned attribute can _only_ _increase_ the size of structure, but not
> > decrease it.
> 
> No, the gcc documentation isn't quite clear there, see the discussion about
> compat_u64 and compat_s64 types. It actually does the right thing when
> you use 'typedef __u64 __attribute__((aligned(64))) compat_64', as my
> patch does.
> 
> 	Arnd <><
> 

Wow!... Thank you for the explanation.
I'll resend the patch soon.

Vasily

-
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/