/* -*- mode: C; c-file-style: "gnu" -*- */

/* policy.c  Bus security policy

 *

 * Copyright (C) 2003, 2004  Red Hat, Inc.

 * Portion Copyright © 2008 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.

 * Licensed under the Academic Free License version 2.1

 * 

 * 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.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 */

#include "policy.h"

#include "services.h"

#include "test.h"

#include "utils.h"

#ifndef __SYMBIAN32__

#include <dbus/dbus-list.h>

#include <dbus/dbus-hash.h>

#include <dbus/dbus-internals.h>

#else

#include "dbus-list.h"

#include "dbus-hash.h"

#include "dbus-internals.h"

#endif //__SYMBIAN32__

BusPolicyRule*

bus_policy_rule_new (BusPolicyRuleType type,

                     dbus_bool_t       allow)

{

  BusPolicyRule *rule;

  rule = dbus_new0 (BusPolicyRule, 1);

  if (rule == NULL)

    return NULL;

  rule->type = type;

  rule->refcount = 1;

  rule->allow = allow;

  switch (rule->type)

    {

    case BUS_POLICY_RULE_USER:

      rule->d.user.uid = DBUS_UID_UNSET;

      break;

    case BUS_POLICY_RULE_GROUP:

      rule->d.group.gid = DBUS_GID_UNSET;

      break;

    case BUS_POLICY_RULE_SEND:

      rule->d.send.message_type = DBUS_MESSAGE_TYPE_INVALID;

      /* allow rules default to TRUE (only requested replies allowed)

       * deny rules default to FALSE (only unrequested replies denied)

       */

      rule->d.send.requested_reply = rule->allow;

      break;

    case BUS_POLICY_RULE_RECEIVE:

      rule->d.receive.message_type = DBUS_MESSAGE_TYPE_INVALID;

      /* allow rules default to TRUE (only requested replies allowed)

       * deny rules default to FALSE (only unrequested replies denied)

       */

      rule->d.receive.requested_reply = rule->allow;

      break;

    case BUS_POLICY_RULE_OWN:

      break;

    }

  return rule;

}

BusPolicyRule *

bus_policy_rule_ref (BusPolicyRule *rule)

{

  _dbus_assert (rule->refcount > 0);

  rule->refcount += 1;

  return rule;

}

void

bus_policy_rule_unref (BusPolicyRule *rule)

{

  _dbus_assert (rule->refcount > 0);

  rule->refcount -= 1;

  if (rule->refcount == 0)

    {

      switch (rule->type)

        {

        case BUS_POLICY_RULE_SEND:

          dbus_free (rule->d.send.path);

          dbus_free (rule->d.send.interface);

          dbus_free (rule->d.send.member);

          dbus_free (rule->d.send.error);

          dbus_free (rule->d.send.destination);

          break;

        case BUS_POLICY_RULE_RECEIVE:

          dbus_free (rule->d.receive.path);

          dbus_free (rule->d.receive.interface);

          dbus_free (rule->d.receive.member);

          dbus_free (rule->d.receive.error);

          dbus_free (rule->d.receive.origin);

          break;

        case BUS_POLICY_RULE_OWN:

          dbus_free (rule->d.own.service_name);

          break;

        case BUS_POLICY_RULE_USER:

          break;

        case BUS_POLICY_RULE_GROUP:

          break;

        }

      dbus_free (rule);

    }

}

struct BusPolicy

{

  int refcount;

  DBusList *default_rules;         /**< Default policy rules */

  DBusList *mandatory_rules;       /**< Mandatory policy rules */

  DBusHashTable *rules_by_uid;     /**< per-UID policy rules */

  DBusHashTable *rules_by_gid;     /**< per-GID policy rules */

  DBusList *at_console_true_rules; /**< console user policy rules where at_console="true"*/

  DBusList *at_console_false_rules; /**< console user policy rules where at_console="false"*/

};

static void

free_rule_func (void *data,

                void *user_data)

{

  BusPolicyRule *rule = data;

  bus_policy_rule_unref (rule);

}

static void

free_rule_list_func (void *data)

{

  DBusList **list = data;

  if (list == NULL) /* DBusHashTable is on crack */

    return;

  _dbus_list_foreach (list, free_rule_func, NULL);

  _dbus_list_clear (list);

  dbus_free (list);

}

BusPolicy*

bus_policy_new (void)

{

  BusPolicy *policy;

  policy = dbus_new0 (BusPolicy, 1);

  if (policy == NULL)

    return NULL;

  policy->refcount = 1;

  policy->rules_by_uid = _dbus_hash_table_new (DBUS_HASH_ULONG,

                                               NULL,

                                               free_rule_list_func);

  if (policy->rules_by_uid == NULL)

    goto failed;

  policy->rules_by_gid = _dbus_hash_table_new (DBUS_HASH_ULONG,

                                               NULL,

                                               free_rule_list_func);

  if (policy->rules_by_gid == NULL)

    goto failed;

  return policy;

 failed:

  bus_policy_unref (policy);

  return NULL;

}

BusPolicy *

bus_policy_ref (BusPolicy *policy)

{

  _dbus_assert (policy->refcount > 0);

  policy->refcount += 1;

  return policy;

}

void

bus_policy_unref (BusPolicy *policy)

{

  _dbus_assert (policy->refcount > 0);

  policy->refcount -= 1;

  if (policy->refcount == 0)

    {

      _dbus_list_foreach (&policy->default_rules, free_rule_func, NULL);

      _dbus_list_clear (&policy->default_rules);

      _dbus_list_foreach (&policy->mandatory_rules, free_rule_func, NULL);

      _dbus_list_clear (&policy->mandatory_rules);

      _dbus_list_foreach (&policy->at_console_true_rules, free_rule_func, NULL);

      _dbus_list_clear (&policy->at_console_true_rules);

      _dbus_list_foreach (&policy->at_console_false_rules, free_rule_func, NULL);

      _dbus_list_clear (&policy->at_console_false_rules);

      if (policy->rules_by_uid)

        {

          _dbus_hash_table_unref (policy->rules_by_uid);

          policy->rules_by_uid = NULL;

        }

      if (policy->rules_by_gid)

        {

          _dbus_hash_table_unref (policy->rules_by_gid);

          policy->rules_by_gid = NULL;

        }

      dbus_free (policy);

    }

}

static dbus_bool_t

add_list_to_client (DBusList        **list,

                    BusClientPolicy  *client)

{

  DBusList *link;

  link = _dbus_list_get_first_link (list);

  while (link != NULL)

    {

      BusPolicyRule *rule = link->data;

      link = _dbus_list_get_next_link (list, link);

      switch (rule->type)

        {

        case BUS_POLICY_RULE_USER:

        case BUS_POLICY_RULE_GROUP:

          /* These aren't per-connection policies */

          break;

        case BUS_POLICY_RULE_OWN:

        case BUS_POLICY_RULE_SEND:

        case BUS_POLICY_RULE_RECEIVE:

          /* These are per-connection */

          if (!bus_client_policy_append_rule (client, rule))

            return FALSE;

          break;

        }

    }

  return TRUE;

}

BusClientPolicy*

bus_policy_create_client_policy (BusPolicy      *policy,

                                 DBusConnection *connection,

                                 DBusError      *error)

{

  BusClientPolicy *client;

  dbus_uid_t uid;

  dbus_bool_t at_console;

  _dbus_assert (dbus_connection_get_is_authenticated (connection));

  _DBUS_ASSERT_ERROR_IS_CLEAR (error);

  client = bus_client_policy_new ();

  if (client == NULL)

    goto nomem;

  if (!add_list_to_client (&policy->default_rules,

                           client))

    goto nomem;

  /* we avoid the overhead of looking up user's groups

   * if we don't have any group rules anyway

   */

  if (_dbus_hash_table_get_n_entries (policy->rules_by_gid) > 0)

    {

      unsigned long *groups;

      int n_groups;

      int i;

      if (!bus_connection_get_groups (connection, &groups, &n_groups, error))

        goto failed;

      i = 0;

      while (i < n_groups)

        {

          DBusList **list;

          list = _dbus_hash_table_lookup_ulong (policy->rules_by_gid,

                                                groups[i]);

          if (list != NULL)

            {

              if (!add_list_to_client (list, client))

                {

                  dbus_free (groups);

                  goto nomem;

                }

            }

          ++i;

        }

      dbus_free (groups);

    }

  if (!dbus_connection_get_unix_user (connection, &uid))

    {

      dbus_set_error (error, DBUS_ERROR_FAILED,

                      "No user ID known for connection, cannot determine security policy\n");

      goto failed;

    }

  if (_dbus_hash_table_get_n_entries (policy->rules_by_uid) > 0)

    {

      DBusList **list;

      list = _dbus_hash_table_lookup_ulong (policy->rules_by_uid,

                                            uid);

      if (list != NULL)

        {

          if (!add_list_to_client (list, client))

            goto nomem;

        }

    }

  /* Add console rules */

  at_console = _dbus_is_console_user (uid, error);

  if (at_console)

    {

      if (!add_list_to_client (&policy->at_console_true_rules, client))

        goto nomem;

    }

  else if (dbus_error_is_set (error) == TRUE)

    {

      goto failed;

    }

  else if (!add_list_to_client (&policy->at_console_false_rules, client))

    {

      goto nomem;

    }

  if (!add_list_to_client (&policy->mandatory_rules,

                           client))

    goto nomem;

  bus_client_policy_optimize (client);

  return client;

 nomem:

  BUS_SET_OOM (error);

 failed:

  _DBUS_ASSERT_ERROR_IS_SET (error);

  if (client)

    bus_client_policy_unref (client);

  return NULL;

}

static dbus_bool_t

list_allows_user (dbus_bool_t           def,

                  DBusList            **list,

                  unsigned long         uid,

                  const unsigned long  *group_ids,

                  int                   n_group_ids)

{

  DBusList *link;

  dbus_bool_t allowed;

  allowed = def;

  link = _dbus_list_get_first_link (list);

  while (link != NULL)

    {

      BusPolicyRule *rule = link->data;

      link = _dbus_list_get_next_link (list, link);

      if (rule->type == BUS_POLICY_RULE_USER)

        {

          _dbus_verbose ("List %p user rule uid="DBUS_UID_FORMAT"\n",

                         list, rule->d.user.uid);

          if (rule->d.user.uid == DBUS_UID_UNSET)

            ; /* '*' wildcard */

          else if (rule->d.user.uid != uid)

            continue;

        }

      else if (rule->type == BUS_POLICY_RULE_GROUP)

        {

          _dbus_verbose ("List %p group rule uid="DBUS_UID_FORMAT"\n",

                         list, rule->d.user.uid);

          if (rule->d.group.gid == DBUS_GID_UNSET)

            ;  /* '*' wildcard */

          else

            {

              int i;

              i = 0;

              while (i < n_group_ids)

                {

                  if (rule->d.group.gid == group_ids[i])

                    break;

                  ++i;

                }

              if (i == n_group_ids)

                continue;

            }

        }

      else

        continue;

      allowed = rule->allow;

    }

  return allowed;

}

dbus_bool_t

bus_policy_allow_user (BusPolicy        *policy,

                       DBusUserDatabase *user_database,

                       unsigned long     uid)

{

  dbus_bool_t allowed;

  unsigned long *group_ids;

  int n_group_ids;

  /* On OOM or error we always reject the user */

  if (!_dbus_user_database_get_groups (user_database,

                                       uid, &group_ids, &n_group_ids, NULL))

    {

      _dbus_verbose ("Did not get any groups for UID %lu\n",

                     uid);

      return FALSE;

    }

  /* Default to "user owning bus" or root can connect */

  allowed = uid == _dbus_getuid ();

  allowed = list_allows_user (allowed,

                              &policy->default_rules,

                              uid,

                              group_ids, n_group_ids);

  allowed = list_allows_user (allowed,

                              &policy->mandatory_rules,

                              uid,

                              group_ids, n_group_ids);

  dbus_free (group_ids);

  _dbus_verbose ("UID %lu allowed = %d\n", uid, allowed);

  return allowed;

}

dbus_bool_t

bus_policy_append_default_rule (BusPolicy      *policy,

                                BusPolicyRule  *rule)

{

  if (!_dbus_list_append (&policy->default_rules, rule))

    return FALSE;

  bus_policy_rule_ref (rule);

  return TRUE;

}

dbus_bool_t

bus_policy_append_mandatory_rule (BusPolicy      *policy,

                                  BusPolicyRule  *rule)

{

  if (!_dbus_list_append (&policy->mandatory_rules, rule))

    return FALSE;

  bus_policy_rule_ref (rule);

  return TRUE;

}

static DBusList**

get_list (DBusHashTable *hash,

          unsigned long  key)

{

  DBusList **list;

  list = _dbus_hash_table_lookup_ulong (hash, key);

  if (list == NULL)

    {

      list = dbus_new0 (DBusList*, 1);

      if (list == NULL)

        return NULL;

      if (!_dbus_hash_table_insert_ulong (hash, key, list))

        {

          dbus_free (list);

          return NULL;

        }

    }