From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Wang Shilong <wangshilong1991@gmail.com>
Cc: linux-ext4@vger.kernel.org, adilger@dilger.ca, lixi@ddn.com,
wshilong@ddn.com
Subject: Re: [PATCH 2/2] e2fsck: fix use after free in calculate_tree()
Date: Mon, 30 Dec 2019 12:06:28 -0500 [thread overview]
Message-ID: <20191230170628.GB125106@mit.edu> (raw)
In-Reply-To: <1574759039-7429-2-git-send-email-wangshilong1991@gmail.com>
On Tue, Nov 26, 2019 at 06:03:59PM +0900, Wang Shilong wrote:
> @@ -725,12 +728,18 @@ static errcode_t calculate_tree(ext2_filsys fs,
> return retval;
> }
> if (c3 == 0) {
> + int delta1 = int_offset;;
> + int delta2 = (char *)root - outdir->buf;
> +
> retval = alloc_blocks(fs, &limit, &int_ent,
> &dx_ent, &int_offset,
> NULL, outdir, i, &c2,
> &c3);
> if (retval)
> return retval;
> + /* outdir->buf might be reallocated */
> + int_limit = (struct ext2_dx_countlimit *)(outdir->buf + delta1);
> + root = (struct ext2_dx_entry *)(outdir->buf + delta2);
>
> }
> dx_ent->block = ext2fs_cpu_to_le32(i);
Um, are you sure
int delta1 = int_offset;;
is correct? I would think
int delta1 = (char *)int_limit - outdir->buf;
is what is needed; it's certainly much more clear.
- Ted
next prev parent reply other threads:[~2019-12-30 17:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-26 9:03 [PATCH 1/2] e2fsck: fix to return ENOMEM in alloc_size_dir() Wang Shilong
2019-11-26 9:03 ` [PATCH 2/2] e2fsck: fix use after free in calculate_tree() Wang Shilong
2019-12-30 11:38 ` Wang Shilong
2019-12-30 17:06 ` Theodore Y. Ts'o [this message]
2019-12-31 0:57 ` Theodore Y. Ts'o
2019-12-31 1:41 ` Wang Shilong
2019-12-31 3:11 ` [PATCH 1/2] e2fsck: fix to return ENOMEM in alloc_size_dir() Theodore Y. Ts'o
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