linux-kernel - Re: [PATCH] eCryptfs - use page_alloc not kmalloc to get a page of memory

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:	Mon, 28 Jul 2008 15:38:48 -0500
From:	Eric Sandeen <sandeen@...hat.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	linux-kernel@...r.kernel.org, mhalcrow@...ibm.com,
	stable@...nel.org
Subject: Re: [PATCH] eCryptfs - use page_alloc not kmalloc to get a page of
 memory

Andrew Morton wrote:
> On Mon, 28 Jul 2008 11:13:03 -0500
> Eric Sandeen <sandeen@...hat.com> wrote:
> 
>> With SLUB debugging turned on in 2.6.26, I was getting memory corruption
>> when testing eCryptfs.  The root cause turned out to be that eCryptfs
>> was doing kmalloc(PAGE_CACHE_SIZE); virt_to_page() and treating that
>> as a nice page-aligned chunk of memory.  But at least with SLUB debugging
>> on, this is not always true, and the page we get from virt_to_page does
>> not necessarily match the PAGE_CACHE_SIZE worth of memory we got from 
>> kmalloc.
>>
>> My simple testcase was 2 loops doing "rm -f fileX; cp /tmp/fileX ." for
>> 2 different multi-megabyte files.  With this change I no longer see
>> the corruption.
> 
> The fix applies to both 2.6.25 and to 2.6.26 and appears to be needed
> in both kernel versions, so I have tagged it for backporting into both.

I agree, thanks.

-Eric
--
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/