/*
   * security/tomoyo/network.c
   *
   * Copyright (C) 2005-2011  NTT DATA CORPORATION
   */
  
  #include "common.h"
  #include <linux/slab.h>
  
  /* Structure for holding inet domain socket's address. */
  struct tomoyo_inet_addr_info {
  	__be16 port;           /* In network byte order. */
  	const __be32 *address; /* In network byte order. */
  	bool is_ipv6;
  };
  
  /* Structure for holding unix domain socket's address. */
  struct tomoyo_unix_addr_info {
  	u8 *addr; /* This may not be '\0' terminated string. */
  	unsigned int addr_len;
  };
  
  /* Structure for holding socket address. */
  struct tomoyo_addr_info {
  	u8 protocol;
  	u8 operation;
  	struct tomoyo_inet_addr_info inet;
  	struct tomoyo_unix_addr_info unix0;
  };
  
  /* String table for socket's protocols. */
  const char * const tomoyo_proto_keyword[TOMOYO_SOCK_MAX] = {
  	[SOCK_STREAM]    = "stream",
  	[SOCK_DGRAM]     = "dgram",
  	[SOCK_RAW]       = "raw",
  	[SOCK_SEQPACKET] = "seqpacket",
  	[0] = " ", /* Dummy for avoiding NULL pointer dereference. */
  	[4] = " ", /* Dummy for avoiding NULL pointer dereference. */
  };
  
  /**
   * tomoyo_parse_ipaddr_union - Parse an IP address.
   *
   * @param: Pointer to "struct tomoyo_acl_param".
   * @ptr:   Pointer to "struct tomoyo_ipaddr_union".
   *
   * Returns true on success, false otherwise.
   */
  bool tomoyo_parse_ipaddr_union(struct tomoyo_acl_param *param,
  			       struct tomoyo_ipaddr_union *ptr)
  {
  	u8 * const min = ptr->ip[0].in6_u.u6_addr8;
  	u8 * const max = ptr->ip[1].in6_u.u6_addr8;
  	char *address = tomoyo_read_token(param);
  	const char *end;
  
  	if (!strchr(address, ':') &&
  	    in4_pton(address, -1, min, '-', &end) > 0) {
  		ptr->is_ipv6 = false;
  		if (!*end)
  			ptr->ip[1].s6_addr32[0] = ptr->ip[0].s6_addr32[0];
  		else if (*end++ != '-' ||
  			 in4_pton(end, -1, max, '\0', &end) <= 0 || *end)
  			return false;
  		return true;
  	}
  	if (in6_pton(address, -1, min, '-', &end) > 0) {
  		ptr->is_ipv6 = true;
  		if (!*end)
  			memmove(max, min, sizeof(u16) * 8);
  		else if (*end++ != '-' ||
  			 in6_pton(end, -1, max, '\0', &end) <= 0 || *end)
  			return false;
  		return true;
  	}
  	return false;
  }
  
  /**
   * tomoyo_print_ipv4 - Print an IPv4 address.
   *
   * @buffer:     Buffer to write to.
   * @buffer_len: Size of @buffer.
   * @min_ip:     Pointer to __be32.
   * @max_ip:     Pointer to __be32.
   *
   * Returns nothing.
   */
  static void tomoyo_print_ipv4(char *buffer, const unsigned int buffer_len,
  			      const __be32 *min_ip, const __be32 *max_ip)
  {
  	snprintf(buffer, buffer_len, "%pI4%c%pI4", min_ip,
  		 *min_ip == *max_ip ? '\0' : '-', max_ip);
  }
  
  /**
   * tomoyo_print_ipv6 - Print an IPv6 address.
   *
   * @buffer:     Buffer to write to.
   * @buffer_len: Size of @buffer.
   * @min_ip:     Pointer to "struct in6_addr".
   * @max_ip:     Pointer to "struct in6_addr".
   *
   * Returns nothing.
   */
  static void tomoyo_print_ipv6(char *buffer, const unsigned int buffer_len,
  			      const struct in6_addr *min_ip,
  			      const struct in6_addr *max_ip)
  {
  	snprintf(buffer, buffer_len, "%pI6c%c%pI6c", min_ip,
  		 !memcmp(min_ip, max_ip, 16) ? '\0' : '-', max_ip);
  }
  
  /**
   * tomoyo_print_ip - Print an IP address.
   *
   * @buf:  Buffer to write to.
   * @size: Size of @buf.
   * @ptr:  Pointer to "struct ipaddr_union".
   *
   * Returns nothing.
   */
  void tomoyo_print_ip(char *buf, const unsigned int size,
  		     const struct tomoyo_ipaddr_union *ptr)
  {
  	if (ptr->is_ipv6)
  		tomoyo_print_ipv6(buf, size, &ptr->ip[0], &ptr->ip[1]);
  	else
  		tomoyo_print_ipv4(buf, size, &ptr->ip[0].s6_addr32[0],
  				  &ptr->ip[1].s6_addr32[0]);
  }
  
  /*
   * Mapping table from "enum tomoyo_network_acl_index" to
   * "enum tomoyo_mac_index" for inet domain socket.
   */
  static const u8 tomoyo_inet2mac
  [TOMOYO_SOCK_MAX][TOMOYO_MAX_NETWORK_OPERATION] = {
  	[SOCK_STREAM] = {
  		[TOMOYO_NETWORK_BIND]    = TOMOYO_MAC_NETWORK_INET_STREAM_BIND,
  		[TOMOYO_NETWORK_LISTEN]  =
  		TOMOYO_MAC_NETWORK_INET_STREAM_LISTEN,
  		[TOMOYO_NETWORK_CONNECT] =
  		TOMOYO_MAC_NETWORK_INET_STREAM_CONNECT,
  	},
  	[SOCK_DGRAM] = {
  		[TOMOYO_NETWORK_BIND]    = TOMOYO_MAC_NETWORK_INET_DGRAM_BIND,
  		[TOMOYO_NETWORK_SEND]    = TOMOYO_MAC_NETWORK_INET_DGRAM_SEND,
  	},
  	[SOCK_RAW]    = {
  		[TOMOYO_NETWORK_BIND]    = TOMOYO_MAC_NETWORK_INET_RAW_BIND,
  		[TOMOYO_NETWORK_SEND]    = TOMOYO_MAC_NETWORK_INET_RAW_SEND,
  	},
  };
  
  /*
   * Mapping table from "enum tomoyo_network_acl_index" to
   * "enum tomoyo_mac_index" for unix domain socket.
   */
  static const u8 tomoyo_unix2mac
  [TOMOYO_SOCK_MAX][TOMOYO_MAX_NETWORK_OPERATION] = {
  	[SOCK_STREAM] = {
  		[TOMOYO_NETWORK_BIND]    = TOMOYO_MAC_NETWORK_UNIX_STREAM_BIND,
  		[TOMOYO_NETWORK_LISTEN]  =
  		TOMOYO_MAC_NETWORK_UNIX_STREAM_LISTEN,
  		[TOMOYO_NETWORK_CONNECT] =
  		TOMOYO_MAC_NETWORK_UNIX_STREAM_CONNECT,
  	},
  	[SOCK_DGRAM] = {
  		[TOMOYO_NETWORK_BIND]    = TOMOYO_MAC_NETWORK_UNIX_DGRAM_BIND,
  		[TOMOYO_NETWORK_SEND]    = TOMOYO_MAC_NETWORK_UNIX_DGRAM_SEND,
  	},
  	[SOCK_SEQPACKET] = {
  		[TOMOYO_NETWORK_BIND]    =
  		TOMOYO_MAC_NETWORK_UNIX_SEQPACKET_BIND,
  		[TOMOYO_NETWORK_LISTEN]  =
  		TOMOYO_MAC_NETWORK_UNIX_SEQPACKET_LISTEN,
  		[TOMOYO_NETWORK_CONNECT] =
  		TOMOYO_MAC_NETWORK_UNIX_SEQPACKET_CONNECT,
  	},
  };
  
  /**
   * tomoyo_same_inet_acl - Check for duplicated "struct tomoyo_inet_acl" entry.
   *
   * @a: Pointer to "struct tomoyo_acl_info".
   * @b: Pointer to "struct tomoyo_acl_info".
   *
   * Returns true if @a == @b except permission bits, false otherwise.
   */
  static bool tomoyo_same_inet_acl(const struct tomoyo_acl_info *a,
  				 const struct tomoyo_acl_info *b)
  {
  	const struct tomoyo_inet_acl *p1 = container_of(a, typeof(*p1), head);
  	const struct tomoyo_inet_acl *p2 = container_of(b, typeof(*p2), head);
  
  	return p1->protocol == p2->protocol &&
  		tomoyo_same_ipaddr_union(&p1->address, &p2->address) &&
  		tomoyo_same_number_union(&p1->port, &p2->port);
  }
  
  /**
   * tomoyo_same_unix_acl - Check for duplicated "struct tomoyo_unix_acl" entry.
   *
   * @a: Pointer to "struct tomoyo_acl_info".
   * @b: Pointer to "struct tomoyo_acl_info".
   *
   * Returns true if @a == @b except permission bits, false otherwise.
   */
  static bool tomoyo_same_unix_acl(const struct tomoyo_acl_info *a,
  				 const struct tomoyo_acl_info *b)
  {
  	const struct tomoyo_unix_acl *p1 = container_of(a, typeof(*p1), head);
  	const struct tomoyo_unix_acl *p2 = container_of(b, typeof(*p2), head);
  
  	return p1->protocol == p2->protocol &&
  		tomoyo_same_name_union(&p1->name, &p2->name);
  }
  
  /**
   * tomoyo_merge_inet_acl - Merge duplicated "struct tomoyo_inet_acl" entry.
   *
   * @a:         Pointer to "struct tomoyo_acl_info".
   * @b:         Pointer to "struct tomoyo_acl_info".
   * @is_delete: True for @a &= ~@b, false for @a |= @b.
   *
   * Returns true if @a is empty, false otherwise.
   */
  static bool tomoyo_merge_inet_acl(struct tomoyo_acl_info *a,
  				  struct tomoyo_acl_info *b,
  				  const bool is_delete)
  {
  	u8 * const a_perm =
  		&container_of(a, struct tomoyo_inet_acl, head)->perm;
  	u8 perm = *a_perm;
  	const u8 b_perm = container_of(b, struct tomoyo_inet_acl, head)->perm;
  
  	if (is_delete)
  		perm &= ~b_perm;
  	else
  		perm |= b_perm;
  	*a_perm = perm;
  	return !perm;
  }
  
  /**
   * tomoyo_merge_unix_acl - Merge duplicated "struct tomoyo_unix_acl" entry.
   *
   * @a:         Pointer to "struct tomoyo_acl_info".
   * @b:         Pointer to "struct tomoyo_acl_info".
   * @is_delete: True for @a &= ~@b, false for @a |= @b.
   *
   * Returns true if @a is empty, false otherwise.
   */
  static bool tomoyo_merge_unix_acl(struct tomoyo_acl_info *a,
  				  struct tomoyo_acl_info *b,
  				  const bool is_delete)
  {
  	u8 * const a_perm =
  		&container_of(a, struct tomoyo_unix_acl, head)->perm;
  	u8 perm = *a_perm;
  	const u8 b_perm = container_of(b, struct tomoyo_unix_acl, head)->perm;
  
  	if (is_delete)
  		perm &= ~b_perm;
  	else
  		perm |= b_perm;
  	*a_perm = perm;
  	return !perm;
  }
  
  /**
   * tomoyo_write_inet_network - Write "struct tomoyo_inet_acl" list.
   *
   * @param: Pointer to "struct tomoyo_acl_param".
   *
   * Returns 0 on success, negative value otherwise.
   *
   * Caller holds tomoyo_read_lock().
   */
  int tomoyo_write_inet_network(struct tomoyo_acl_param *param)
  {
  	struct tomoyo_inet_acl e = { .head.type = TOMOYO_TYPE_INET_ACL };
  	int error = -EINVAL;
  	u8 type;
  	const char *protocol = tomoyo_read_token(param);
  	const char *operation = tomoyo_read_token(param);
  
  	for (e.protocol = 0; e.protocol < TOMOYO_SOCK_MAX; e.protocol++)
  		if (!strcmp(protocol, tomoyo_proto_keyword[e.protocol]))
  			break;
  	for (type = 0; type < TOMOYO_MAX_NETWORK_OPERATION; type++)
  		if (tomoyo_permstr(operation, tomoyo_socket_keyword[type]))
  			e.perm |= 1 << type;
  	if (e.protocol == TOMOYO_SOCK_MAX || !e.perm)
  		return -EINVAL;
  	if (param->data[0] == '@') {
  		param->data++;
  		e.address.group =
  			tomoyo_get_group(param, TOMOYO_ADDRESS_GROUP);
  		if (!e.address.group)
  			return -ENOMEM;
  	} else {
  		if (!tomoyo_parse_ipaddr_union(param, &e.address))
  			goto out;
  	}
  	if (!tomoyo_parse_number_union(param, &e.port) ||
  	    e.port.values[1] > 65535)
  		goto out;
  	error = tomoyo_update_domain(&e.head, sizeof(e), param,
  				     tomoyo_same_inet_acl,
  				     tomoyo_merge_inet_acl);
  out:
  	tomoyo_put_group(e.address.group);
  	tomoyo_put_number_union(&e.port);
  	return error;
  }
  
  /**
   * tomoyo_write_unix_network - Write "struct tomoyo_unix_acl" list.
   *
   * @param: Pointer to "struct tomoyo_acl_param".
   *
   * Returns 0 on success, negative value otherwise.
   */
  int tomoyo_write_unix_network(struct tomoyo_acl_param *param)
  {
  	struct tomoyo_unix_acl e = { .head.type = TOMOYO_TYPE_UNIX_ACL };
  	int error;
  	u8 type;
  	const char *protocol = tomoyo_read_token(param);
  	const char *operation = tomoyo_read_token(param);
  
  	for (e.protocol = 0; e.protocol < TOMOYO_SOCK_MAX; e.protocol++)
  		if (!strcmp(protocol, tomoyo_proto_keyword[e.protocol]))
  			break;
  	for (type = 0; type < TOMOYO_MAX_NETWORK_OPERATION; type++)
  		if (tomoyo_permstr(operation, tomoyo_socket_keyword[type]))
  			e.perm |= 1 << type;
  	if (e.protocol == TOMOYO_SOCK_MAX || !e.perm)
  		return -EINVAL;
  	if (!tomoyo_parse_name_union(param, &e.name))
  		return -EINVAL;
  	error = tomoyo_update_domain(&e.head, sizeof(e), param,
  				     tomoyo_same_unix_acl,
  				     tomoyo_merge_unix_acl);
  	tomoyo_put_name_union(&e.name);
  	return error;
  }
  
  /**
   * tomoyo_audit_net_log - Audit network log.
   *
   * @r:         Pointer to "struct tomoyo_request_info".
   * @family:    Name of socket family ("inet" or "unix").
   * @protocol:  Name of protocol in @family.
   * @operation: Name of socket operation.
   * @address:   Name of address.
   *
   * Returns 0 on success, negative value otherwise.
   */
  static int tomoyo_audit_net_log(struct tomoyo_request_info *r,
  				const char *family, const u8 protocol,
  				const u8 operation, const char *address)
  {
  	return tomoyo_supervisor(r, "network %s %s %s %s
  ", family,
  				 tomoyo_proto_keyword[protocol],
  				 tomoyo_socket_keyword[operation], address);
  }
  
  /**
   * tomoyo_audit_inet_log - Audit INET network log.
   *
   * @r: Pointer to "struct tomoyo_request_info".
   *
   * Returns 0 on success, negative value otherwise.
   */
  static int tomoyo_audit_inet_log(struct tomoyo_request_info *r)
  {
  	char buf[128];
  	int len;
  	const __be32 *address = r->param.inet_network.address;
  
  	if (r->param.inet_network.is_ipv6)
  		tomoyo_print_ipv6(buf, sizeof(buf), (const struct in6_addr *)
  				  address, (const struct in6_addr *) address);
  	else
  		tomoyo_print_ipv4(buf, sizeof(buf), address, address);
  	len = strlen(buf);
  	snprintf(buf + len, sizeof(buf) - len, " %u",
  		 r->param.inet_network.port);
  	return tomoyo_audit_net_log(r, "inet", r->param.inet_network.protocol,
  				    r->param.inet_network.operation, buf);
  }
  
  /**
   * tomoyo_audit_unix_log - Audit UNIX network log.
   *
   * @r: Pointer to "struct tomoyo_request_info".
   *
   * Returns 0 on success, negative value otherwise.
   */
  static int tomoyo_audit_unix_log(struct tomoyo_request_info *r)
  {
  	return tomoyo_audit_net_log(r, "unix", r->param.unix_network.protocol,
  				    r->param.unix_network.operation,
  				    r->param.unix_network.address->name);
  }
  
  /**
   * tomoyo_check_inet_acl - Check permission for inet domain socket operation.
   *
   * @r:   Pointer to "struct tomoyo_request_info".
   * @ptr: Pointer to "struct tomoyo_acl_info".
   *
   * Returns true if granted, false otherwise.
   */
  static bool tomoyo_check_inet_acl(struct tomoyo_request_info *r,
  				  const struct tomoyo_acl_info *ptr)
  {
  	const struct tomoyo_inet_acl *acl =
  		container_of(ptr, typeof(*acl), head);
  	const u8 size = r->param.inet_network.is_ipv6 ? 16 : 4;
  
  	if (!(acl->perm & (1 << r->param.inet_network.operation)) ||
  	    !tomoyo_compare_number_union(r->param.inet_network.port,
  					 &acl->port))
  		return false;
  	if (acl->address.group)
  		return tomoyo_address_matches_group
  			(r->param.inet_network.is_ipv6,
  			 r->param.inet_network.address, acl->address.group);
  	return acl->address.is_ipv6 == r->param.inet_network.is_ipv6 &&
  		memcmp(&acl->address.ip[0],
  		       r->param.inet_network.address, size) <= 0 &&
  		memcmp(r->param.inet_network.address,
  		       &acl->address.ip[1], size) <= 0;
  }
  
  /**
   * tomoyo_check_unix_acl - Check permission for unix domain socket operation.
   *
   * @r:   Pointer to "struct tomoyo_request_info".
   * @ptr: Pointer to "struct tomoyo_acl_info".
   *
   * Returns true if granted, false otherwise.
   */
  static bool tomoyo_check_unix_acl(struct tomoyo_request_info *r,
  				  const struct tomoyo_acl_info *ptr)
  {
  	const struct tomoyo_unix_acl *acl =
  		container_of(ptr, typeof(*acl), head);
  
  	return (acl->perm & (1 << r->param.unix_network.operation)) &&
  		tomoyo_compare_name_union(r->param.unix_network.address,
  					  &acl->name);
  }
  
  /**
   * tomoyo_inet_entry - Check permission for INET network operation.
   *
   * @address: Pointer to "struct tomoyo_addr_info".
   *
   * Returns 0 on success, negative value otherwise.
   */
  static int tomoyo_inet_entry(const struct tomoyo_addr_info *address)
  {
  	const int idx = tomoyo_read_lock();
  	struct tomoyo_request_info r;
  	int error = 0;
  	const u8 type = tomoyo_inet2mac[address->protocol][address->operation];
  
  	if (type && tomoyo_init_request_info(&r, NULL, type)
  	    != TOMOYO_CONFIG_DISABLED) {
  		r.param_type = TOMOYO_TYPE_INET_ACL;
  		r.param.inet_network.protocol = address->protocol;
  		r.param.inet_network.operation = address->operation;
  		r.param.inet_network.is_ipv6 = address->inet.is_ipv6;
  		r.param.inet_network.address = address->inet.address;
  		r.param.inet_network.port = ntohs(address->inet.port);
  		do {
  			tomoyo_check_acl(&r, tomoyo_check_inet_acl);
  			error = tomoyo_audit_inet_log(&r);
  		} while (error == TOMOYO_RETRY_REQUEST);
  	}
  	tomoyo_read_unlock(idx);
  	return error;
  }
  
  /**
   * tomoyo_check_inet_address - Check permission for inet domain socket's operation.
   *
   * @addr:     Pointer to "struct sockaddr".
   * @addr_len: Size of @addr.
   * @port:     Port number.
   * @address:  Pointer to "struct tomoyo_addr_info".
   *
   * Returns 0 on success, negative value otherwise.
   */
  static int tomoyo_check_inet_address(const struct sockaddr *addr,
  				     const unsigned int addr_len,
  				     const u16 port,
  				     struct tomoyo_addr_info *address)
  {
  	struct tomoyo_inet_addr_info *i = &address->inet;
  
  	switch (addr->sa_family) {
  	case AF_INET6:
  		if (addr_len < SIN6_LEN_RFC2133)
  			goto skip;
  		i->is_ipv6 = true;
  		i->address = (__be32 *)
  			((struct sockaddr_in6 *) addr)->sin6_addr.s6_addr;
  		i->port = ((struct sockaddr_in6 *) addr)->sin6_port;
  		break;
  	case AF_INET:
  		if (addr_len < sizeof(struct sockaddr_in))
  			goto skip;
  		i->is_ipv6 = false;
  		i->address = (__be32 *)
  			&((struct sockaddr_in *) addr)->sin_addr;
  		i->port = ((struct sockaddr_in *) addr)->sin_port;
  		break;
  	default:
  		goto skip;
  	}
  	if (address->protocol == SOCK_RAW)
  		i->port = htons(port);
  	return tomoyo_inet_entry(address);
  skip:
  	return 0;
  }
  
  /**
   * tomoyo_unix_entry - Check permission for UNIX network operation.
   *
   * @address: Pointer to "struct tomoyo_addr_info".
   *
   * Returns 0 on success, negative value otherwise.
   */
  static int tomoyo_unix_entry(const struct tomoyo_addr_info *address)
  {
  	const int idx = tomoyo_read_lock();
  	struct tomoyo_request_info r;
  	int error = 0;
  	const u8 type = tomoyo_unix2mac[address->protocol][address->operation];
  
  	if (type && tomoyo_init_request_info(&r, NULL, type)
  	    != TOMOYO_CONFIG_DISABLED) {
  		char *buf = address->unix0.addr;
  		int len = address->unix0.addr_len - sizeof(sa_family_t);
  
  		if (len <= 0) {
  			buf = "anonymous";
  			len = 9;
  		} else if (buf[0]) {
  			len = strnlen(buf, len);
  		}
  		buf = tomoyo_encode2(buf, len);
  		if (buf) {
  			struct tomoyo_path_info addr;
  
  			addr.name = buf;
  			tomoyo_fill_path_info(&addr);
  			r.param_type = TOMOYO_TYPE_UNIX_ACL;
  			r.param.unix_network.protocol = address->protocol;
  			r.param.unix_network.operation = address->operation;
  			r.param.unix_network.address = &addr;
  			do {
  				tomoyo_check_acl(&r, tomoyo_check_unix_acl);
  				error = tomoyo_audit_unix_log(&r);
  			} while (error == TOMOYO_RETRY_REQUEST);
  			kfree(buf);
  		} else
  			error = -ENOMEM;
  	}
  	tomoyo_read_unlock(idx);
  	return error;
  }
  
  /**
   * tomoyo_check_unix_address - Check permission for unix domain socket's operation.
   *
   * @addr:     Pointer to "struct sockaddr".
   * @addr_len: Size of @addr.
   * @address:  Pointer to "struct tomoyo_addr_info".
   *
   * Returns 0 on success, negative value otherwise.
   */
  static int tomoyo_check_unix_address(struct sockaddr *addr,
  				     const unsigned int addr_len,
  				     struct tomoyo_addr_info *address)
  {
  	struct tomoyo_unix_addr_info *u = &address->unix0;
  
  	if (addr->sa_family != AF_UNIX)
  		return 0;
  	u->addr = ((struct sockaddr_un *) addr)->sun_path;
  	u->addr_len = addr_len;
  	return tomoyo_unix_entry(address);
  }
  
  /**
   * tomoyo_kernel_service - Check whether I'm kernel service or not.
   *
   * Returns true if I'm kernel service, false otherwise.
   */
  static bool tomoyo_kernel_service(void)
  {
  	/* Nothing to do if I am a kernel service. */
  	return segment_eq(get_fs(), KERNEL_DS);
  }
  
  /**
   * tomoyo_sock_family - Get socket's family.
   *
   * @sk: Pointer to "struct sock".
   *
   * Returns one of PF_INET, PF_INET6, PF_UNIX or 0.
   */
  static u8 tomoyo_sock_family(struct sock *sk)
  {
  	u8 family;
  
  	if (tomoyo_kernel_service())
  		return 0;
  	family = sk->sk_family;
  	switch (family) {
  	case PF_INET:
  	case PF_INET6:
  	case PF_UNIX:
  		return family;
  	default:
  		return 0;
  	}
  }
  
  /**
   * tomoyo_socket_listen_permission - Check permission for listening a socket.
   *
   * @sock: Pointer to "struct socket".
   *
   * Returns 0 on success, negative value otherwise.
   */
  int tomoyo_socket_listen_permission(struct socket *sock)
  {
  	struct tomoyo_addr_info address;
  	const u8 family = tomoyo_sock_family(sock->sk);
  	const unsigned int type = sock->type;
  	struct sockaddr_storage addr;
  	int addr_len;
  
  	if (!family || (type != SOCK_STREAM && type != SOCK_SEQPACKET))
  		return 0;
  	{
  		const int error = sock->ops->getname(sock, (struct sockaddr *)
  						     &addr, &addr_len, 0);
  
  		if (error)
  			return error;
  	}
  	address.protocol = type;
  	address.operation = TOMOYO_NETWORK_LISTEN;
  	if (family == PF_UNIX)
  		return tomoyo_check_unix_address((struct sockaddr *) &addr,
  						 addr_len, &address);
  	return tomoyo_check_inet_address((struct sockaddr *) &addr, addr_len,
  					 0, &address);
  }
  
  /**
   * tomoyo_socket_connect_permission - Check permission for setting the remote address of a socket.
   *
   * @sock:     Pointer to "struct socket".
   * @addr:     Pointer to "struct sockaddr".
   * @addr_len: Size of @addr.
   *
   * Returns 0 on success, negative value otherwise.
   */
  int tomoyo_socket_connect_permission(struct socket *sock,
  				     struct sockaddr *addr, int addr_len)
  {
  	struct tomoyo_addr_info address;
  	const u8 family = tomoyo_sock_family(sock->sk);
  	const unsigned int type = sock->type;
  
  	if (!family)
  		return 0;
  	address.protocol = type;
  	switch (type) {
  	case SOCK_DGRAM:
  	case SOCK_RAW:
  		address.operation = TOMOYO_NETWORK_SEND;
  		break;
  	case SOCK_STREAM:
  	case SOCK_SEQPACKET:
  		address.operation = TOMOYO_NETWORK_CONNECT;
  		break;
  	default:
  		return 0;
  	}
  	if (family == PF_UNIX)
  		return tomoyo_check_unix_address(addr, addr_len, &address);
  	return tomoyo_check_inet_address(addr, addr_len, sock->sk->sk_protocol,
  					 &address);
  }
  
  /**
   * tomoyo_socket_bind_permission - Check permission for setting the local address of a socket.
   *
   * @sock:     Pointer to "struct socket".
   * @addr:     Pointer to "struct sockaddr".
   * @addr_len: Size of @addr.
   *
   * Returns 0 on success, negative value otherwise.
   */
  int tomoyo_socket_bind_permission(struct socket *sock, struct sockaddr *addr,
  				  int addr_len)
  {
  	struct tomoyo_addr_info address;
  	const u8 family = tomoyo_sock_family(sock->sk);
  	const unsigned int type = sock->type;
  
  	if (!family)
  		return 0;
  	switch (type) {
  	case SOCK_STREAM:
  	case SOCK_DGRAM:
  	case SOCK_RAW:
  	case SOCK_SEQPACKET:
  		address.protocol = type;
  		address.operation = TOMOYO_NETWORK_BIND;
  		break;
  	default:
  		return 0;
  	}
  	if (family == PF_UNIX)
  		return tomoyo_check_unix_address(addr, addr_len, &address);
  	return tomoyo_check_inet_address(addr, addr_len, sock->sk->sk_protocol,
  					 &address);
  }
  
  /**
   * tomoyo_socket_sendmsg_permission - Check permission for sending a datagram.
   *
   * @sock: Pointer to "struct socket".
   * @msg:  Pointer to "struct msghdr".
   * @size: Unused.
   *
   * Returns 0 on success, negative value otherwise.
   */
  int tomoyo_socket_sendmsg_permission(struct socket *sock, struct msghdr *msg,
  				     int size)
  {
  	struct tomoyo_addr_info address;
  	const u8 family = tomoyo_sock_family(sock->sk);
  	const unsigned int type = sock->type;
  
  	if (!msg->msg_name || !family ||
  	    (type != SOCK_DGRAM && type != SOCK_RAW))
  		return 0;
  	address.protocol = type;
  	address.operation = TOMOYO_NETWORK_SEND;
  	if (family == PF_UNIX)
  		return tomoyo_check_unix_address((struct sockaddr *)
  						 msg->msg_name,
  						 msg->msg_namelen, &address);
  	return tomoyo_check_inet_address((struct sockaddr *) msg->msg_name,
  					 msg->msg_namelen,
  					 sock->sk->sk_protocol, &address);
  }