[PATCH] fs/ntfs3: fix null pointer dereference in d_flags_for_inode

Liangbin Lian
2022-05-06T03:47:04Z

ntfs_read_mft may return inode with null i_op, cause null pointer dereference in d_flags_for_inode (inode->i_op->get_link).
Reproduce:
- sudo mount -t ntfs3 -o loop ntfs.img ntfs
- ls ntfs/'$Extend/$Quota'

The call trace is shown below (striped):
BUG: kernel NULL pointer dereference, address: 0000000000000008
CPU: 0 PID: 577 Comm: ls Tainted: G OE 5.16.0-0.bpo.4-amd64 #1 Debian 5.16.12-1~bpo11+1
RIP: 0010:d_flags_for_inode+0x65/0x90
Call Trace:
ntfs_lookup
+--- dir_search_u
| +--- ntfs_iget5
| +--- ntfs_read_mft
+--- d_splice_alias
+--- __d_add
+--- d_flags_for_inode

Signed-off-by: Liangbin Lian <jjm2473@gmail.com>
---
fs/ntfs3/inode.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 9eab11e3b..b68d26fa8 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -45,7 +45,6 @@ static struct inode *ntfs_read_mft(struct inode *inode,
struct MFT_REC *rec;
struct runs_tree *run;

- inode->i_op = NULL;
/* Setup 'uid' and 'gid' */
inode->i_uid = sbi->options->fs_uid;
inode->i_gid = sbi->options->fs_gid;
--
2.32.0 (Apple Git-132)