From: Ferry Meng <mengferry@linux.alibaba.com>
Date: Mon, 20 May 2024 02:40:24 +0000 (+0800)
Subject: ocfs2: strict bound check before memcmp in ocfs2_xattr_find_entry()
X-Git-Tag: v6.11-rc1~84^2~95
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=af77c4fc1871847b528d58b7fdafb4aa1f6a9262;p=thirdparty%2Fkernel%2Flinux.git

ocfs2: strict bound check before memcmp in ocfs2_xattr_find_entry()

xattr in ocfs2 maybe 'non-indexed', which 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 crafted poisonous
images.

Link: https://lkml.kernel.org/r/20240520024024.1976129-2-joseph.qi@linux.alibaba.com
Signed-off-by: Ferry Meng <mengferry@linux.alibaba.com>
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reported-by: lei lu <llfamsec@gmail.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Mark Fasheh <mark@fasheh.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 8aea94c907397..35c0cc2a51af8 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -1068,7 +1068,7 @@ static int ocfs2_xattr_find_entry(struct inode *inode, int name_index,
 {
 	struct ocfs2_xattr_entry *entry;
 	size_t name_len;
-	int i, cmp = 1;
+	int i, name_offset, cmp = 1;
 
 	if (name == NULL)
 		return -EINVAL;
@@ -1083,10 +1083,15 @@ static int ocfs2_xattr_find_entry(struct inode *inode, int name_index,
 		cmp = name_index - ocfs2_xattr_get_type(entry);
 		if (!cmp)
 			cmp = name_len - entry->xe_name_len;
-		if (!cmp)
-			cmp = memcmp(name, (xs->base +
-				     le16_to_cpu(entry->xe_name_offset)),
-				     name_len);
+		if (!cmp) {
+			name_offset = le16_to_cpu(entry->xe_name_offset);
+			if ((xs->base + name_offset + name_len) > xs->end) {
+				ocfs2_error(inode->i_sb,
+					    "corrupted xattr entries");
+				return -EFSCORRUPTED;
+			}
+			cmp = memcmp(name, (xs->base + name_offset), name_len);
+		}
 		if (cmp == 0)
 			break;
 		entry += 1;