From: Colin Ian King <colin.king@canonical.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org,
David Howells <dhowells@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: fs: hfs: Possible issue with increment of extent
Date: Fri, 31 Aug 2018 14:56:46 +0100 [thread overview]
Message-ID: <7036d8c5-92cb-257b-848a-33e0ba5829e5@canonical.com> (raw)
In-Reply-To: <20180831135614.GC19965@ZenIV.linux.org.uk>
On 31/08/18 14:56, Al Viro wrote:
> On Fri, Aug 31, 2018 at 02:39:11PM +0100, Colin Ian King wrote:
>> Hi,
>>
>> Static analysis has picked up a potential issue with an out of bounds
>> read in fs/hfs/extent.c; the following for-loop in hfs_free_fork()
>> increments i and also extent while also reading extent[i].count. This
>> looks incorrect to me, I think the increment of extent is not needed:
>>
>> for (i = 0; i < 3; extent++, i++)
>> blocks += be16_to_cpu(extent[i].count);
>>
>> res = hfs_free_extents(sb, extent, blocks, blocks);
>>
>> I'm not familiar enough with the code to conclude that removing the
>> increment of extent is necessary a correct fix just in case I'm missing
>> something subtle here.
>
> Goes back to commit d1081202f1d0 (in bk-to-git historical tree)
> Author: Andrew Morton <akpm@osdl.org>
> Date: Wed Feb 25 16:17:36 2004 -0800
>
> [PATCH] HFS rewrite
>
> From: Roman Zippel <zippel@linux-m68k.org>
>
> and it's almost certainly a bug in there, judging by the code nearby...
>
OK, I'll send a fix then.
Colin
prev parent reply other threads:[~2018-08-31 18:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-31 13:39 fs: hfs: Possible issue with increment of extent Colin Ian King
2018-08-31 13:56 ` Al Viro
2018-08-31 13:56 ` Colin Ian King [this message]
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