// SPDX-License-Identifier: GPL-2.0-or-later/* General persistent per-UID keyrings register * * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ #include <linux/user_namespace.h>#include <linux/cred.h> #include "internal.h" unsigned persistent_keyring_expiry = 3 * 24 * 3600; /* Expire after 3 days of non-use */ /* * Create the persistent keyring register for the current user namespace. * * Called with the namespace's sem locked for writing. */static int key_create_persistent_register(struct user_namespace *ns){	struct key *reg = keyring_alloc(".persistent_register",					KUIDT_INIT(0), KGIDT_INIT(0),					current_cred(),					((KEY_POS_ALL & ~KEY_POS_SETATTR) |					 KEY_USR_VIEW | KEY_USR_READ),					KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);	if (IS_ERR(reg))		return PTR_ERR(reg); 	ns->persistent_keyring_register = reg;	return 0;} /* * Create the persistent keyring for the specified user. * * Called with the namespace's sem locked for writing. */static key_ref_t key_create_persistent(struct user_namespace *ns, kuid_t uid,				       struct keyring_index_key *index_key){	struct key *persistent;	key_ref_t reg_ref, persistent_ref; 	if (!ns->persistent_keyring_register) {		long err = key_create_persistent_register(ns);		if (err < 0)			return ERR_PTR(err);	} else {		reg_ref = make_key_ref(ns->persistent_keyring_register, true);		persistent_ref = find_key_to_update(reg_ref, index_key);		if (persistent_ref)			return persistent_ref;	} 	persistent = keyring_alloc(index_key->description,				   uid, INVALID_GID, current_cred(),				   ((KEY_POS_ALL & ~KEY_POS_SETATTR) |				    KEY_USR_VIEW | KEY_USR_READ),				   KEY_ALLOC_NOT_IN_QUOTA, NULL,				   ns->persistent_keyring_register);	if (IS_ERR(persistent))		return ERR_CAST(persistent); 	return make_key_ref(persistent, true);} /* * Get the persistent keyring for a specific UID and link it to the nominated * keyring. */static long key_get_persistent(struct user_namespace *ns, kuid_t uid,			       key_ref_t dest_ref){	struct keyring_index_key index_key;	struct key *persistent;	key_ref_t reg_ref, persistent_ref;	char buf[32];	long ret; 	/* Look in the register if it exists */	index_key.type = &key_type_keyring;	index_key.description = buf;	index_key.desc_len = sprintf(buf, "_persistent.%u", from_kuid(ns, uid)); 	if (ns->persistent_keyring_register) {		reg_ref = make_key_ref(ns->persistent_keyring_register, true);		down_read(&ns->persistent_keyring_register_sem);		persistent_ref = find_key_to_update(reg_ref, &index_key);		up_read(&ns->persistent_keyring_register_sem); 		if (persistent_ref)			goto found;	} 	/* It wasn't in the register, so we'll need to create it.  We might	 * also need to create the register.	 */	down_write(&ns->persistent_keyring_register_sem);	persistent_ref = key_create_persistent(ns, uid, &index_key);	up_write(&ns->persistent_keyring_register_sem);	if (!IS_ERR(persistent_ref))		goto found; 	return PTR_ERR(persistent_ref); found:	ret = key_task_permission(persistent_ref, current_cred(), KEY_NEED_LINK);	if (ret == 0) {		persistent = key_ref_to_ptr(persistent_ref);		ret = key_link(key_ref_to_ptr(dest_ref), persistent);		if (ret == 0) {			key_set_timeout(persistent, persistent_keyring_expiry);			ret = persistent->serial;		}	} 	key_ref_put(persistent_ref);	return ret;} /* * Get the persistent keyring for a specific UID and link it to the nominated * keyring. */long keyctl_get_persistent(uid_t _uid, key_serial_t destid){	struct user_namespace *ns = current_user_ns();	key_ref_t dest_ref;	kuid_t uid;	long ret; 	/* -1 indicates the current user */	if (_uid == (uid_t)-1) {		uid = current_uid();	} else {		uid = make_kuid(ns, _uid);		if (!uid_valid(uid))			return -EINVAL; 		/* You can only see your own persistent cache if you're not		 * sufficiently privileged.		 */		if (!uid_eq(uid, current_uid()) &&		    !uid_eq(uid, current_euid()) &&		    !ns_capable(ns, CAP_SETUID))			return -EPERM;	} 	/* There must be a destination keyring */	dest_ref = lookup_user_key(destid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);	if (IS_ERR(dest_ref))		return PTR_ERR(dest_ref);	if (key_ref_to_ptr(dest_ref)->type != &key_type_keyring) {		ret = -ENOTDIR;		goto out_put_dest;	} 	ret = key_get_persistent(ns, uid, dest_ref); out_put_dest:	key_ref_put(dest_ref);	return ret;}