linux-kernel - Re: [PATCH] lib/dma-debug: check for vmalloc buffers used with the DMA-API

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: <20120918131842.GL2505@amd.com>
Date:	Tue, 18 Sep 2012 15:18:42 +0200
From:	Joerg Roedel <joerg.roedel@....com>
To:	Jan Luebbe <jlu@...gutronix.de>
CC:	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] lib/dma-debug: check for vmalloc buffers used with the
 DMA-API

On Mon, Sep 03, 2012 at 01:00:04PM +0200, Jan Luebbe wrote:
> Signed-off-by: Jan Luebbe <jlu@...gutronix.de>
> ---
> I'm not sure why we don't check for high memory, is there any problem
> with this approach?
> 
>  lib/dma-debug.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/lib/dma-debug.c b/lib/dma-debug.c
> index 66ce414..7d60ff0 100644
> --- a/lib/dma-debug.c
> +++ b/lib/dma-debug.c
> @@ -944,6 +944,9 @@ static void check_for_illegal_area(struct device *dev, void *addr, unsigned long
>  	if (overlap(addr, len, _text, _etext) ||
>  	    overlap(addr, len, __start_rodata, __end_rodata))
>  		err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
> +	if (is_vmalloc_or_module_addr(addr) ||
> +	    is_vmalloc_or_module_addr(addr+len))
> +		err_printk(dev, NULL, "DMA-API: device driver maps memory from vmalloc or module address range [addr=%p] [len=%lu]\n", addr, len);

Hmm, this only checks whether the start or end+1 address is in the
vmalloc/module range. I think it is better to check for overlap against
VMALLOC_START/END and do a seperate overlap check for MODULES_VADDR and
MODULES_END when needed.

Thanks,

	Joerg

-- 
AMD Operating System Research Center

Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, 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/