[PATCH 6.1 30/73] ocfs2: add bounds checking to ocfs2_xattr_find_entry()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ferry Meng <mengferry@linux.alibaba.com>

[ Upstream commit 9e3041fecdc8f78a5900c3aa51d3d756e73264d6 ]

Add a paranoia check to make sure it doesn't stray beyond valid memory
region containing ocfs2 xattr entries when scanning for a match.  It will
prevent out-of-bound access in case of crafted images.

Link: https://lkml.kernel.org/r/20240520024024.1976129-1-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: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: af77c4fc1871 ("ocfs2: strict bound check before memcmp in ocfs2_xattr_find_entry()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ocfs2/xattr.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 55699c5735413..61213b7e4dfbe 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -1066,7 +1066,7 @@ ssize_t ocfs2_listxattr(struct dentry *dentry,
 	return i_ret + b_ret;
 }
 
-static int ocfs2_xattr_find_entry(int name_index,
+static int ocfs2_xattr_find_entry(struct inode *inode, int name_index,
 				  const char *name,
 				  struct ocfs2_xattr_search *xs)
 {
@@ -1080,6 +1080,10 @@ static int ocfs2_xattr_find_entry(int name_index,
 	name_len = strlen(name);
 	entry = xs->here;
 	for (i = 0; i < le16_to_cpu(xs->header->xh_count); i++) {
+		if ((void *)entry >= xs->end) {
+			ocfs2_error(inode->i_sb, "corrupted xattr entries");
+			return -EFSCORRUPTED;
+		}
 		cmp = name_index - ocfs2_xattr_get_type(entry);
 		if (!cmp)
 			cmp = name_len - entry->xe_name_len;
@@ -1170,7 +1174,7 @@ static int ocfs2_xattr_ibody_get(struct inode *inode,
 	xs->base = (void *)xs->header;
 	xs->here = xs->header->xh_entries;
 
-	ret = ocfs2_xattr_find_entry(name_index, name, xs);
+	ret = ocfs2_xattr_find_entry(inode, name_index, name, xs);
 	if (ret)
 		return ret;
 	size = le64_to_cpu(xs->here->xe_value_size);
@@ -2702,7 +2706,7 @@ static int ocfs2_xattr_ibody_find(struct inode *inode,
 
 	/* Find the named attribute. */
 	if (oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL) {
-		ret = ocfs2_xattr_find_entry(name_index, name, xs);
+		ret = ocfs2_xattr_find_entry(inode, name_index, name, xs);
 		if (ret && ret != -ENODATA)
 			return ret;
 		xs->not_found = ret;
@@ -2837,7 +2841,7 @@ static int ocfs2_xattr_block_find(struct inode *inode,
 		xs->end = (void *)(blk_bh->b_data) + blk_bh->b_size;
 		xs->here = xs->header->xh_entries;
 
-		ret = ocfs2_xattr_find_entry(name_index, name, xs);
+		ret = ocfs2_xattr_find_entry(inode, name_index, name, xs);
 	} else
 		ret = ocfs2_xattr_index_block_find(inode, blk_bh,
 						   name_index,
-- 
2.43.0