From: Joseph Qi <joseph.qi@linux.alibaba.com>
To: Ferry Meng <mengferry@linux.alibaba.com>,
Mark Fasheh <mark@fasheh.com>, Joel Becker <jlbec@evilplan.org>,
ocfs2-devel@lists.linux.dev
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] ocfs2: strict bound check before memcmp in ocfs2_xattr_find_entry()
Date: Thu, 16 May 2024 09:41:58 +0800 [thread overview]
Message-ID: <03f031e5-ed9c-4794-8f08-8a4007c1d704@linux.alibaba.com> (raw)
In-Reply-To: <20240515132934.69511-3-mengferry@linux.alibaba.com>
On 5/15/24 9:29 PM, Ferry Meng wrote:
> xattr in ocfs2 maybe not INLINE, but saved with additional space
> requested. It's better to check if the memory is out of bound before
> memcmp, although this possibility mainly comes from custom poisonous
> images.
Specifically, this only addresses the case non-indexed xattr.
>
> Signed-off-by: Ferry Meng <mengferry@linux.alibaba.com>
> ---
> fs/ocfs2/xattr.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
> index 37be4a286faf..4ceb0cb4cb71 100644
> --- a/fs/ocfs2/xattr.c
> +++ b/fs/ocfs2/xattr.c
> @@ -1083,10 +1083,15 @@ static int ocfs2_xattr_find_entry(struct inode *inode, void *end,
> cmp = name_index - ocfs2_xattr_get_type(entry);
Or define a local variable 'offset' for le16_to_cpu(entry->xe_name_offset).
Thanks,
Joseph
> if (!cmp)
> cmp = name_len - entry->xe_name_len;
> - if (!cmp)
> + if (!cmp) {
> + if ((xs->base + le16_to_cpu(entry->xe_name_offset) + name_len) > end) {
> + ocfs2_error(inode->i_sb, "corrupted xattr entries");
> + return -EFSCORRUPTED;
> + }
> cmp = memcmp(name, (xs->base +
> le16_to_cpu(entry->xe_name_offset)),
> name_len);
> + }
> if (cmp == 0)
> break;
> entry += 1;
prev parent reply other threads:[~2024-05-16 1:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-15 13:29 [PATCH 0/2] ocfs2: add checks in ocfs2_xattr_find_entry() to avoid potential out-of-bound access Ferry Meng
2024-05-15 13:29 ` [PATCH 1/2] ocfs2: add bounds checking to ocfs2_xattr_find_entry() Ferry Meng
2024-05-16 1:25 ` Joseph Qi
2024-05-15 13:29 ` [PATCH 2/2] ocfs2: strict bound check before memcmp in ocfs2_xattr_find_entry() Ferry Meng
2024-05-16 1:41 ` Joseph Qi [this message]
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