smb/server: fix posix state check for directory rename

Pass the source ksmbd_file to the rename helpers and use the per-handle
POSIX create-context state when deciding whether open children block a
directory rename.

work->tcon->posix_extensions only records whether POSIX extensions were
negotiated on the connection.  It does not indicate that the handles were
opened with POSIX create contexts.

Reproducer:

  1. server: systemctl start ksmbd
  2. client: mount -t cifs //${server_ip}/export /mnt
     # without posix option
  3. client: mkdir /mnt/dir1/; touch /mnt/dir1/file
  4. client: tail -f /mnt/dir1/file # open file
  5. client: mv /mnt/dir1 /mnt/dir2

Without this fix, the rename can succeed when it should fail with
"Permission denied".

Fixes: c841bd3d8dec ("ksmbd: deny renaming directory with open children")
Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

5 files changed, 11 insertions, 8 deletions

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index e214d27e4d37..80f5791c687b 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -7690,7 +7690,7 @@ static int smb2_rename(struct ksmbd_work *work,
 		goto out;
 
 	smb_break_all_levII_oplock_rename(work, fp);
-	rc = ksmbd_vfs_rename(work, &fp->filp->f_path, new_name, flags);
+	rc = ksmbd_vfs_rename(work, fp, new_name, flags);
 out:
 	kfree(new_name);
 	return rc;
diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c
index ff86e0e88177..0e7d66b0e899 100644
--- a/fs/smb/server/vfs.c
+++ b/fs/smb/server/vfs.c
@@ -678,9 +678,10 @@ int ksmbd_vfs_check_rename_share(struct ksmbd_work *work,
 	return err;
 }
 
-int ksmbd_vfs_rename(struct ksmbd_work *work, const struct path *old_path,
+int ksmbd_vfs_rename(struct ksmbd_work *work, struct ksmbd_file *old_fp,
 			     char *newname, int flags)
 {
+	const struct path *old_path = &old_fp->filp->f_path;
 	struct dentry *old_child = old_path->dentry;
 	struct path new_path;
 	struct qstr new_last;
@@ -717,8 +718,7 @@ retry:
 	if (err)
 		goto out_drop_write;
 
-	if (!work->tcon->posix_extensions && d_is_dir(old_child) &&
-	    ksmbd_has_open_files(old_child)) {
+	if (d_is_dir(old_child) && ksmbd_has_open_files(old_fp)) {
 		err = -EACCES;
 		goto out3;
 	}
diff --git a/fs/smb/server/vfs.h b/fs/smb/server/vfs.h
index 1818b3f1971c..55d099de71f5 100644
--- a/fs/smb/server/vfs.h
+++ b/fs/smb/server/vfs.h
@@ -88,8 +88,8 @@ int ksmbd_vfs_remove_file(struct ksmbd_work *work, const struct path *path);
 int ksmbd_vfs_link(struct ksmbd_work *work,
 		   const char *oldname, const char *newname);
 int ksmbd_vfs_getattr(const struct path *path, struct kstat *stat);
-int ksmbd_vfs_rename(struct ksmbd_work *work, const struct path *old_path,
-			     char *newname, int flags);
+int ksmbd_vfs_rename(struct ksmbd_work *work, struct ksmbd_file *old_fp,
+			 char *newname, int flags);
 int ksmbd_vfs_check_rename_share(struct ksmbd_work *work,
 				 const struct path *old_path);
 int ksmbd_vfs_truncate(struct ksmbd_work *work,
diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c
index a35df2ab59c9..eac9886eb6e3 100644
--- a/fs/smb/server/vfs_cache.c
+++ b/fs/smb/server/vfs_cache.c
@@ -1137,8 +1137,9 @@ struct ksmbd_file *ksmbd_lookup_fd_inode(struct dentry *dentry)
 	return NULL;
 }
 
-bool ksmbd_has_open_files(struct dentry *dentry)
+bool ksmbd_has_open_files(struct ksmbd_file *old_fp)
 {
+	struct dentry *dentry = old_fp->filp->f_path.dentry;
 	struct ksmbd_file *fp;
 	unsigned int id;
 	bool ret = false;
@@ -1151,6 +1152,8 @@ bool ksmbd_has_open_files(struct dentry *dentry)
 			continue;
 		if (fp_dentry == dentry)
 			continue;
+		if (old_fp->is_posix_ctxt && fp->is_posix_ctxt)
+			continue;
 		if (is_subdir(fp_dentry, dentry)) {
 			ret = true;
 			break;
diff --git a/fs/smb/server/vfs_cache.h b/fs/smb/server/vfs_cache.h
index d80f379d4e12..127ea4987e3f 100644
--- a/fs/smb/server/vfs_cache.h
+++ b/fs/smb/server/vfs_cache.h
@@ -212,7 +212,7 @@ bool ksmbd_has_stream_without_delete_share(struct ksmbd_file *fp);
 int ksmbd_close_fd_app_instance_id(char *app_instance_id);
 struct ksmbd_file *ksmbd_lookup_fd_cguid(char *cguid);
 struct ksmbd_file *ksmbd_lookup_fd_inode(struct dentry *dentry);
-bool ksmbd_has_open_files(struct dentry *dentry);
+bool ksmbd_has_open_files(struct ksmbd_file *old_fp);
 unsigned int ksmbd_open_durable_fd(struct ksmbd_file *fp);
 struct ksmbd_file *ksmbd_open_fd(struct ksmbd_work *work, struct file *filp);
 void ksmbd_launch_ksmbd_durable_scavenger(void);