From: tytso@mit.edu
To: Eric Sandeen <sandeen@redhat.com>
Cc: ext4 development <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH] resize2fs: fix uninit group test accessing invalid memory
Date: Fri, 5 Feb 2010 22:35:39 -0500 [thread overview]
Message-ID: <20100206033539.GA321@thunk.org> (raw)
In-Reply-To: <4B5E0966.3040704@redhat.com>
On Mon, Jan 25, 2010 at 03:13:10PM -0600, Eric Sandeen wrote:
> Commit 74128f8d7e93fe633aa87951319a4afd252a4494 added tests
> for uninit groups, but did it after the group counter
> increment in 2 loops, so we were testing past the end
> of the ->group_desc[] array:
This patch is not correct; the test for uninit and the calculation for
old_desc_blk needs to be for the next group, not the previous block.
I believe this patch is the correct one instead.
- Ted
commit 40b09fbe01fac8722b699b29f796e18550d68c84
Author: Theodore Ts'o <tytso@mit.edu>
Date: Fri Feb 5 22:25:03 2010 -0500
resize2fs: Fix fix uninit group test accessing invalid memory
Commit 74128f8 added tests for uninit groups, but it could access past
the end of the group_desc[] array after processing the last group:
==19668== Invalid read of size 2
==19668== at 0x40518C: resize_fs (resize2fs.c:1824)
==19668== by 0x405A46: main (main.c:451)
==19668== Address 0x5a0d002 is not stack'd, malloc'd or (recently) free'd
==19668==
==19668== Invalid read of size 2
==19668== at 0x405391: resize_fs (resize2fs.c:1864)
==19668== by 0x405A46: main (main.c:451)
==19668== Address 0x5a0d002 is not stack'd, malloc'd or (recently) free'd
==19668==
It was found by Eric Sandeen running the regression suite through
valgrind.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/resize/resize2fs.c b/resize/resize2fs.c
index 75c4721..346fd53 100644
--- a/resize/resize2fs.c
+++ b/resize/resize2fs.c
@@ -1819,6 +1819,8 @@ static errcode_t ext2fs_calculate_summary_stats(ext2_filsys fs)
group_free;
ext2fs_group_desc_csum_set(fs, group);
group++;
+ if (group >= fs->group_desc_count)
+ break;
count = 0;
group_free = 0;
uninit = (fs->group_desc[group].bg_flags &
@@ -1859,6 +1861,8 @@ static errcode_t ext2fs_calculate_summary_stats(ext2_filsys fs)
group_free;
ext2fs_group_desc_csum_set(fs, group);
group++;
+ if (group >= fs->group_desc_count)
+ break;
count = 0;
group_free = 0;
uninit = (fs->group_desc[group].bg_flags &
prev parent reply other threads:[~2010-02-06 3:35 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-25 21:13 [PATCH] resize2fs: fix uninit group test accessing invalid memory Eric Sandeen
2010-02-06 3:35 ` tytso [this message]
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