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From: Mark Tinguely <tinguely@sgi.com>
To: Eric Sandeen <sandeen@sandeen.net>
Cc: hch@infradead.org, xfs@oss.sgi.com
Subject: Re: [PATCH V2] xfsprogs: Fix possible unallocated memory access in fiemap
Date: Thu, 21 Feb 2013 09:28:08 -0600	[thread overview]
Message-ID: <51263D08.5060307@sgi.com> (raw)
In-Reply-To: <5102F4BE.6060009@sandeen.net>

On 01/25/13 15:10, Eric Sandeen wrote:
> (Based on original patch by Lukas Czerner&  comments by Dave Chinner)
>
> Currently we could access unallocated memory in fiemap because we're
> using uninitialized variable 'fiemap' in fiemap_f(). In fact this has
> been spotted on x390s machine where xfs_io would segfault.
>
> The problem happens in the for cycle which seems to be intended to
> compute the header item spacing. However at that point the fiemap
> structure has just been allocated and does not contain any extents
> yet, so it is entirely useless and it never actually worked.
>
> This patch delays the format calculation until the first batch
> of extents has come in for analysis.
>
> Signed-off-by: Eric Sandeen<sandeen@redhat.com>
> ---

A working calculated format is a great improvement.

Reviewed-by: Mark Tinguely <tinguely@sgi.com>

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           reply	other threads:[~2013-02-21 15:28 UTC|newest]

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