fuse: readdirplus: sanity checks

Add sanity checks before adding or updating an entry with data received
from readdirplus.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@vger.kernel.org

fs/fuse/dir.c

@@ -1223,6 +1223,12 @@ static int fuse_direntplus_link(struct file *file,
 		if (name.name[1] == '.' && name.len == 2)
 			return 0;
 	}
+
+	if (invalid_nodeid(o->nodeid))
+		return -EIO;
+	if (!fuse_valid_type(o->attr.mode))
+		return -EIO;
+
 	fc = get_fuse_conn(dir);
 
 	name.hash = full_name_hash(name.name, name.len);
@@ -1231,10 +1237,14 @@ static int fuse_direntplus_link(struct file *file,
 		inode = dentry->d_inode;
 		if (!inode) {
 			d_drop(dentry);
-		} else if (get_node_id(inode) != o->nodeid) {
+		} else if (get_node_id(inode) != o->nodeid ||
+			   ((o->attr.mode ^ inode->i_mode) & S_IFMT)) {
 			err = d_invalidate(dentry);
 			if (err)
 				goto out;
+		} else if (is_bad_inode(inode)) {
+			err = -EIO;
+			goto out;
 		} else {
 			struct fuse_inode *fi;
 			fi = get_fuse_inode(inode);