linux-kernel - Re: [PATCH] bitmap: separate bitmap parsing for user buffer and kernel buffer

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]

Date:	05 Oct 2006 21:57:04 +0200
From:	Andi Kleen <ak@...e.de>
To:	Andrew Morton <akpm@...l.org>
Cc:	Joe Korty <joe.korty@...r.com>,
	Inaky Perez-Gonzalez <inaky@...ux.intel.com>,
	Paul Jackson <pj@....com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] bitmap: separate bitmap parsing for user buffer and kernel buffer

Andrew Morton <akpm@...l.org> writes:

> On Wed, 4 Oct 2006 17:56:30 -0700
> Reinette Chatre <reinette.chatre@...ux.intel.com> wrote:
> 
> > +			if (is_user) {
> > +				if (__get_user(c, buf++))
> > +					return -EFAULT;
> > +			}
> > +			else
> > +				c = *buf++;
> 
> Is this actually needed?  __get_user(kernel_address) works OK and (believe
> it or not, given all the stuff it involves) boils down to a single instruction.		

It is needed on lots of architectures that use separate address spaces
like sparc64, m68k, s390 (and on x86 with 4:4 patches) 

-Andi
-
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/