linux-kernel - Re: [PATCH 2/4] dma-debug: add debugfs file for driver filter

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: <20090602133321.GA2231@amd.com>
Date:	Tue, 2 Jun 2009 15:33:21 +0200
From:	Joerg Roedel <joerg.roedel@....com>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/4] dma-debug: add debugfs file for driver filter

On Mon, Jun 01, 2009 at 03:04:18PM -0700, Andrew Morton wrote:
> On Thu, 28 May 2009 17:19:29 +0200
> Joerg Roedel <joerg.roedel@....com> wrote:
> 
> > +	/*
> > +	 * We can't copy from userspace directly. Access to
> > +	 * current_driver_name is protected with a write_lock with irqs
> > +	 * disabled. Since copy_from_user can fault and may sleep we
> > +	 * need to copy to temporary buffer first
> > +	 */
> > +	len = min(count, len);
> > +	if (copy_from_user(buf, userbuf, len))
> > +		return -EFAULT;
> > +
> > +	buf[NAME_MAX_LEN - 1] = 0;
> 
> Might be able to use strncpy_from_user() here.
>

Hmm, no, not in this place because I can't be sure that userspace passes
a NULL-terminated string. So setting a character in the resulting string
to \0 is always required. This eliminates the benefit of
strncpy_from_user() here.

Joerg

-- 
           | Advanced Micro Devices GmbH
 Operating | Karl-Hammerschmidt-Str. 34, 85609 Dornach bei München
 System    | 
 Research  | Geschäftsführer: Thomas M. McCoy, Giuliano Meroni
 Center    | Sitz: Dornach, Gemeinde Aschheim, Landkreis München
           | Registergericht München, HRB Nr. 43632

--
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/