From: Christoph Hellwig <hch@infradead.org>
To: Lukas Czerner <lczerner@redhat.com>
Cc: hch@infradead.org, xfs@oss.sgi.com
Subject: Re: [PATCH v2] xfs: fix possible overflow in xfs_ioc_trim()
Date: Tue, 6 Sep 2011 11:33:01 -0400 [thread overview]
Message-ID: <20110906153301.GA21675@infradead.org> (raw)
In-Reply-To: <1315322977-22736-1-git-send-email-lczerner@redhat.com>
On Tue, Sep 06, 2011 at 05:29:37PM +0200, Lukas Czerner wrote:
> In xfs_ioc_trim it is possible that start+len might overflow. Fix it by
> decrementing the len so that start+len equals to the file system size in
> the worst case.
>
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
> @@ -146,6 +146,7 @@ xfs_ioc_trim(
> unsigned int granularity = q->limits.discard_granularity;
> struct fstrim_range range;
> xfs_fsblock_t start, len, minlen;
> + xfs_fsblock_t max_blks = mp->m_sb.sb_dblocks;
> xfs_agnumber_t start_agno, end_agno, agno;
> __uint64_t blocks_trimmed = 0;
> int error, last_error = 0;
> @@ -171,7 +172,8 @@ xfs_ioc_trim(
> start_agno = XFS_FSB_TO_AGNO(mp, start);
> if (start_agno >= mp->m_sb.sb_agcount)
> return -XFS_ERROR(EINVAL);
> -
> + if (len > max_blks)
> + len = max_blks - start;
Is this really the correct check?
Shouldn't it be
if (start + len > max_blks)
len = max_blks - start;
I'd also just use the mp->m_sb.sb_dblocks value directly instead
of assigning it to a local variable.
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next prev parent reply other threads:[~2011-09-06 15:33 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-06 15:29 [PATCH v2] xfs: fix possible overflow in xfs_ioc_trim() Lukas Czerner
2011-09-06 15:33 ` Christoph Hellwig [this message]
2011-09-07 10:05 ` Lukas Czerner
2011-09-07 11:21 ` Christoph Hellwig
2011-09-07 12:26 ` Lukas Czerner
2011-09-20 13:36 ` Lukas Czerner
2011-09-20 17:12 ` Christoph Hellwig
2011-09-21 7:46 ` Lukas Czerner
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