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From: Mark Tinguely <tinguely@sgi.com>
To: Eric Sandeen <sandeen@redhat.com>
Cc: xfs-oss <xfs@oss.sgi.com>
Subject: Re: [PATCH] xfs: catch invalid negative blknos in _xfs_buf_find()
Date: Wed, 26 Nov 2014 10:38:05 -0600	[thread overview]
Message-ID: <547601ED.7060704@sgi.com> (raw)
In-Reply-To: <546D15E3.5000200@redhat.com>

On 11/19/14 16:12, Eric Sandeen wrote:
> Here blkno is a daddr_t, which is a __s64; it's possible to hold
> a value which is negative, and thus pass the (blkno>= eofs)
> test.  Then we try to do a xfs_perag_get() for a ridiculous
> agno via xfs_daddr_to_agno(), and bad things happen when that
> fails, and returns a null pag which is dereferenced shortly
> thereafter.
>
> Found via a user-supplied fuzzed image...
>
> Signed-off-by: Eric Sandeen<sandeen@redhat.com>
> ---

Looks good.

I did a little playing with sending the try lock failure (EAGAIN?) and 
EFSCORRUPT error status up the stack. It looked straight forward and 
could save a xfs_buf allocation when we know it is not necessary.

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

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      parent reply	other threads:[~2014-11-26 16:38 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-19 22:12 [PATCH] xfs: catch invalid negative blknos in _xfs_buf_find() Eric Sandeen
2014-11-19 22:27 ` Eric Sandeen
2014-11-26 15:58 ` Eric Sandeen
2014-11-26 16:38 ` Mark Tinguely [this message]

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