/* RxRPC security handling
   *
   * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   */
  
  #include <linux/module.h>
  #include <linux/net.h>
  #include <linux/skbuff.h>
  #include <linux/udp.h>
  #include <linux/crypto.h>
  #include <net/sock.h>
  #include <net/af_rxrpc.h>
  #include <keys/rxrpc-type.h>
  #include "ar-internal.h"
  
  static LIST_HEAD(rxrpc_security_methods);
  static DECLARE_RWSEM(rxrpc_security_sem);
  
  /*
   * get an RxRPC security module
   */
  static struct rxrpc_security *rxrpc_security_get(struct rxrpc_security *sec)
  {
  	return try_module_get(sec->owner) ? sec : NULL;
  }
  
  /*
   * release an RxRPC security module
   */
  static void rxrpc_security_put(struct rxrpc_security *sec)
  {
  	module_put(sec->owner);
  }
  
  /*
   * look up an rxrpc security module
   */
  static struct rxrpc_security *rxrpc_security_lookup(u8 security_index)
  {
  	struct rxrpc_security *sec = NULL;
  
  	_enter("");
  
  	down_read(&rxrpc_security_sem);
  
  	list_for_each_entry(sec, &rxrpc_security_methods, link) {
  		if (sec->security_index == security_index) {
  			if (unlikely(!rxrpc_security_get(sec)))
  				break;
  			goto out;
  		}
  	}
  
  	sec = NULL;
  out:
  	up_read(&rxrpc_security_sem);
  	_leave(" = %p [%s]", sec, sec ? sec->name : "");
  	return sec;
  }
  
  /**
   * rxrpc_register_security - register an RxRPC security handler
   * @sec: security module
   *
   * register an RxRPC security handler for use by RxRPC
   */
  int rxrpc_register_security(struct rxrpc_security *sec)
  {
  	struct rxrpc_security *psec;
  	int ret;
  
  	_enter("");
  	down_write(&rxrpc_security_sem);
  
  	ret = -EEXIST;
  	list_for_each_entry(psec, &rxrpc_security_methods, link) {
  		if (psec->security_index == sec->security_index)
  			goto out;
  	}
  
  	list_add(&sec->link, &rxrpc_security_methods);
  
  	printk(KERN_NOTICE "RxRPC: Registered security type %d '%s'
  ",
  	       sec->security_index, sec->name);
  	ret = 0;
  
  out:
  	up_write(&rxrpc_security_sem);
  	_leave(" = %d", ret);
  	return ret;
  }
  
  EXPORT_SYMBOL_GPL(rxrpc_register_security);
  
  /**
   * rxrpc_unregister_security - unregister an RxRPC security handler
   * @sec: security module
   *
   * unregister an RxRPC security handler
   */
  void rxrpc_unregister_security(struct rxrpc_security *sec)
  {
  
  	_enter("");
  	down_write(&rxrpc_security_sem);
  	list_del_init(&sec->link);
  	up_write(&rxrpc_security_sem);
  
  	printk(KERN_NOTICE "RxRPC: Unregistered security type %d '%s'
  ",
  	       sec->security_index, sec->name);
  }
  
  EXPORT_SYMBOL_GPL(rxrpc_unregister_security);
  
  /*
   * initialise the security on a client connection
   */
  int rxrpc_init_client_conn_security(struct rxrpc_connection *conn)
  {
  	struct rxrpc_key_token *token;
  	struct rxrpc_security *sec;
  	struct key *key = conn->key;
  	int ret;
  
  	_enter("{%d},{%x}", conn->debug_id, key_serial(key));
  
  	if (!key)
  		return 0;
  
  	ret = key_validate(key);
  	if (ret < 0)
  		return ret;
  
  	if (!key->payload.data)
  		return -EKEYREJECTED;
  	token = key->payload.data;
  
  	sec = rxrpc_security_lookup(token->security_index);
  	if (!sec)
  		return -EKEYREJECTED;
  	conn->security = sec;
  
  	ret = conn->security->init_connection_security(conn);
  	if (ret < 0) {
  		rxrpc_security_put(conn->security);
  		conn->security = NULL;
  		return ret;
  	}
  
  	_leave(" = 0");
  	return 0;
  }
  
  /*
   * initialise the security on a server connection
   */
  int rxrpc_init_server_conn_security(struct rxrpc_connection *conn)
  {
  	struct rxrpc_security *sec;
  	struct rxrpc_local *local = conn->trans->local;
  	struct rxrpc_sock *rx;
  	struct key *key;
  	key_ref_t kref;
  	char kdesc[5+1+3+1];
  
  	_enter("");
  
  	sprintf(kdesc, "%u:%u", ntohs(conn->service_id), conn->security_ix);
  
  	sec = rxrpc_security_lookup(conn->security_ix);
  	if (!sec) {
  		_leave(" = -ENOKEY [lookup]");
  		return -ENOKEY;
  	}
  
  	/* find the service */
  	read_lock_bh(&local->services_lock);
  	list_for_each_entry(rx, &local->services, listen_link) {
  		if (rx->service_id == conn->service_id)
  			goto found_service;
  	}
  
  	/* the service appears to have died */
  	read_unlock_bh(&local->services_lock);
  	rxrpc_security_put(sec);
  	_leave(" = -ENOENT");
  	return -ENOENT;
  
  found_service:
  	if (!rx->securities) {
  		read_unlock_bh(&local->services_lock);
  		rxrpc_security_put(sec);
  		_leave(" = -ENOKEY");
  		return -ENOKEY;
  	}
  
  	/* look through the service's keyring */
  	kref = keyring_search(make_key_ref(rx->securities, 1UL),
  			      &key_type_rxrpc_s, kdesc);
  	if (IS_ERR(kref)) {
  		read_unlock_bh(&local->services_lock);
  		rxrpc_security_put(sec);
  		_leave(" = %ld [search]", PTR_ERR(kref));
  		return PTR_ERR(kref);
  	}
  
  	key = key_ref_to_ptr(kref);
  	read_unlock_bh(&local->services_lock);
  
  	conn->server_key = key;
  	conn->security = sec;
  
  	_leave(" = 0");
  	return 0;
  }
  
  /*
   * secure a packet prior to transmission
   */
  int rxrpc_secure_packet(const struct rxrpc_call *call,
  			struct sk_buff *skb,
  			size_t data_size,
  			void *sechdr)
  {
  	if (call->conn->security)
  		return call->conn->security->secure_packet(
  			call, skb, data_size, sechdr);
  	return 0;
  }
  
  /*
   * secure a packet prior to transmission
   */
  int rxrpc_verify_packet(const struct rxrpc_call *call, struct sk_buff *skb,
  			u32 *_abort_code)
  {
  	if (call->conn->security)
  		return call->conn->security->verify_packet(
  			call, skb, _abort_code);
  	return 0;
  }
  
  /*
   * clear connection security
   */
  void rxrpc_clear_conn_security(struct rxrpc_connection *conn)
  {
  	_enter("{%d}", conn->debug_id);
  
  	if (conn->security) {
  		conn->security->clear(conn);
  		rxrpc_security_put(conn->security);
  		conn->security = NULL;
  	}
  
  	key_put(conn->key);
  	key_put(conn->server_key);
  }