[PATCH 5.4 120/154] ocfs2: validate l_tree_depth to avoid out-of-bounds access

Greg Kroah-Hartman
2025-04-08T12:09:21Z

From: Vasiliy Kovalev <kovalev@altlinux.org>

[ Upstream commit a406aff8c05115119127c962cbbbbd202e1973ef ]

The l_tree_depth field is 16-bit (__le16), but the actual maximum depth is
limited to OCFS2_MAX_PATH_DEPTH.

Add a check to prevent out-of-bounds access if l_tree_depth has an invalid
value, which may occur when reading from a corrupted mounted disk [1].

Link: https://lkml.kernel.org/r/20250214084908.736528-1-kovalev@altlinux.org
Fixes: ccd979bdbce9 ("[PATCH] OCFS2: The Second Oracle Cluster Filesystem")
Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org>
Reported-by: syzbot+66c146268dc88f4341fd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=66c146268dc88f4341fd [1]
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Kurt Hackel <kurt.hackel@oracle.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Vasiliy Kovalev <kovalev@altlinux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ocfs2/alloc.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 52ccd8d4ed820..0d2dbf3fded2a 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -1799,6 +1799,14 @@ static int __ocfs2_find_path(struct ocfs2_caching_info *ci,

el = root_el;
while (el->l_tree_depth) {
+ if (unlikely(le16_to_cpu(el->l_tree_depth) >= OCFS2_MAX_PATH_DEPTH)) {
+ ocfs2_error(ocfs2_metadata_cache_get_super(ci),
+ "Owner %llu has invalid tree depth %u in extent list\n",
+ (unsigned long long)ocfs2_metadata_cache_owner(ci),
+ le16_to_cpu(el->l_tree_depth));
+ ret = -EROFS;
+ goto out;
+ }
if (le16_to_cpu(el->l_next_free_rec) == 0) {
ocfs2_error(ocfs2_metadata_cache_get_super(ci),
"Owner %llu has empty extent list at depth %u\n",
--
2.39.5