linux-kernel - [PATCH v2] ocfs2: validate l_tree_depth to avoid out-of-bounds access

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250214080038.735185-1-kovalev@altlinux.org>
Date: Fri, 14 Feb 2025 11:00:38 +0300
From: Vasiliy Kovalev <kovalev@...linux.org>
To: joseph.qi@...ux.alibaba.com
Cc: jlbec@...lplan.org,
	kovalev@...linux.org,
	kurt.hackel@...cle.com,
	linux-kernel@...r.kernel.org,
	lvc-project@...uxtesting.org,
	mark@...heh.com,
	ocfs2-devel@...ts.linux.dev,
	syzbot+66c146268dc88f4341fd@...kaller.appspotmail.com
Subject: [PATCH v2] ocfs2: validate l_tree_depth to avoid out-of-bounds access

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].

Fixes: ccd979bdbce9 ("[PATCH] OCFS2: The Second Oracle Cluster Filesystem")
Reported-by: syzbot+66c146268dc88f4341fd@...kaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=66c146268dc88f4341fd [1]
Signed-off-by: Vasiliy Kovalev <kovalev@...linux.org>
---
v2: Restricted depth to OCFS2_MAX_PATH_DEPTH and moved the check
    to __ocfs2_find_path().
---
 fs/ocfs2/alloc.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 4414743b638e8..cec8fc5cb8e87 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -1803,6 +1803,14 @@ 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",
-- 
2.42.2