[PATCH] ocfs2: validate l_tree_depth to avoid out-of-bounds access
From: Vasiliy Kovalev
Date: Thu Feb 13 2025 - 14:17:05 EST
The l_tree_depth field in struct ocfs2_extent_list is defined
as __le16, but according to the comments in the structure
definition, the high 8 bits must not be used, meaning its
maximum valid value is 255.
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@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=66c146268dc88f4341fd [1]
Signed-off-by: Vasiliy Kovalev <kovalev@xxxxxxxxxxxx>
---
fs/ocfs2/extent_map.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
index 930150ed5db15..0d9c25fdec029 100644
--- a/fs/ocfs2/extent_map.c
+++ b/fs/ocfs2/extent_map.c
@@ -415,6 +415,15 @@ static int ocfs2_get_clusters_nocache(struct inode *inode,
tree_height = le16_to_cpu(el->l_tree_depth);
if (tree_height > 0) {
+ if (unlikely(tree_height > 255)) {
+ ocfs2_error(inode->i_sb,
+ "Inode %lu has too large l_tree_depth=%u in leaf block %llu\n",
+ inode->i_ino, tree_height,
+ (unsigned long long)di_bh->b_blocknr);
+ ret = -EROFS;
+ goto out;
+ }
+
ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
&eb_bh);
if (ret) {
--
2.42.2