Hello.
Thank you for reporting this bug.
The bug happens because we don't initialize i_op for records in $Extend.
We tested patch on our side, let me know if patch helps you too.
fs/ntfs3: Fix missing i_op in ntfs_read_mft
There is null pointer dereference because i_op == NULL.
The bug happens because we don't initialize i_op for records in $Extend.
Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block")
Reported-by: Liangbin Lian <jjm2473@xxxxxxxxx>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@xxxxxxxxxxxxxxxxxxxx>
diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 879952254071..b2cc1191be69 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -430,6 +430,7 @@ static struct inode *ntfs_read_mft(struct inode *inode,
} else if (fname && fname->home.low == cpu_to_le32(MFT_REC_EXTEND) &&
fname->home.seq == cpu_to_le16(MFT_REC_EXTEND)) {
/* Records in $Extend are not a files or general directories. */
+ inode->i_op = &ntfs_file_inode_operations;
} else {
err = -EINVAL;
goto out;
On 5/6/22 06:46, Liangbin Lian wrote:
ntfs_read_mft may return inode with null i_op, cause null pointer dereference in d_flags_for_inode (inode->i_op->get_link).
Reproduce:
- sudo mount -t ntfs3 -o loop ntfs.img ntfs
- ls ntfs/'$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@xxxxxxxxx>
---
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;