[PATCH] ocfs2: Add i_size check for dir

[Edward Adam Davis]

When the i_size of dir is too large, it will cause limit to overflow and
be less than de_buf, ultimately resulting in last_de not being initialized
and causing uaf issue.

Reported-and-tested-by: syzbot+5a64828fcc4c2ad9b04f@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
---
 fs/ocfs2/dir.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index d620d4c53c6f..c308dba6d213 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -3343,6 +3343,8 @@ static int ocfs2_find_dir_space_id(struct inode *dir, struct buffer_head *di_bh,
 	unsigned long offset = 0;
 	unsigned int rec_len, new_rec_len, free_space;
 
+	if (i_size_read(dir) > OCFS2_MAX_BLOCKSIZE)
+		return -EINVAL;
 	/*
 	 * This calculates how many free bytes we'd have in block zero, should
 	 * this function force expansion to an extent tree.
-- 
2.43.0