/*

* Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:

*

*/

package com.nokia.mj.impl.security.midp.authorization;

import java.security.Permission;

import java.util.Vector;

import java.security.AccessControlException;

import com.nokia.mj.impl.utils.Uid;

import com.nokia.mj.impl.security.midp.common.PolicyBasedPermissionImpl;

import com.nokia.mj.impl.security.midp.common.UserPermission;

import com.nokia.mj.impl.security.midp.common.UserSecuritySettings;

import com.nokia.mj.impl.security.midp.common.PermissionMappingTable;

import com.nokia.mj.impl.security.midp.common.MIDPPermission;

import com.nokia.mj.impl.security.midp.common.GeneralSecuritySettings;

import com.nokia.mj.impl.security.midp.common.SecurityExtensionsReader;

import com.nokia.mj.impl.security.common.PermissionBase;

import com.nokia.mj.impl.security.midp.storage.*;

import com.nokia.mj.impl.storage.StorageSession;

import com.nokia.mj.impl.utils.exception.UserCancelException;

/**

 * MIDP specific AccessController.

 * At installation time, a MIDlet suite is granted a set of permissions.

 * At runtime, when the MIDlet is trying to access some protected

 * functionality, AccessController consults the set of granted permissions

 * to decide if the MIDlet is allowed to access the protected

 * functionality or not.

 * The MIDP access control is based on the imply mechanism applied on the

 * MIDlet suite's set of effective permissions.

 */

public final class AccessControllerImpl

{

    // each instance has a list of granted permissions and an associated prompt handler

    private Uid iAppUID;

    private SecurityPromptHandler iSecurityPromptHandler;

    private StorageSession iStorageSession;

    /**

     * Checks if the calling entity (e.g. MIDlet suite) has access to

     * functionality protected by given permission. If the permission is

     * allowed by the security policy, this method returns normally;

     * otherwise, it throws an AccessControlException.

     * Caller of this method is prompted if the given permission is

     * implied by a USER permission

     * @param p Permission to be checked

     * @throws AccessControlException is permission is not granted

     */

    public void checkPermission(Permission p)

    {

        SecurityStorage storage = new SecurityStorage(iStorageSession);

        try

        {

            // resolve the given permission against the set of granted permissions

            Vector resolvedPermissions = queryPermission(p, storage);

            // if the permission was resolved, check if granting it requires

            // user interaction

            boolean unresolvedUserPermission = false;

            for (int i=0; i<resolvedPermissions.size(); i++)

            {

                PolicyBasedPermissionImpl resolvedPermission =

                    (PolicyBasedPermissionImpl)resolvedPermissions.elementAt(i);

                if (resolvedPermission.getUserSecuritySettings() != null)

                {

                    if (resolvedPermission.getPromptDetails() != null)

                    {

                        handleUserPermission(p, resolvedPermission, storage);

                        return;

                    }

                    else

                    {

                        // user permission without prompt info

                        unresolvedUserPermission = true;

                    }

                }

                else

                {

                    // the permission was implied by a non user permission as well

                    // -> reset the flag for user permission

                    unresolvedUserPermission = false;

                }

            }

            if (unresolvedUserPermission)

            {

                // the checked permission was implied by only by user permission(s)

                // for which there were no prompt details (user could not be

                // prompted) -> fail

                fail(p);

            }

        }

        finally

        {

            storage.close();

        }

    }

    /**

     * Checks if the calling entity (e.g. MIDlet suite) has access to

     * functionality protected by given permission (identified by name).

     *

     * @param permissionName Name of the permission to be checked

     * @return               0 if the permission is denied

     *                       1 if the permission is allowed

     *                       -1 if the status of the permission is

     *                       unknown due to e.g. it requires user interaction

     */

    public int checkPermission(String permissionName)

    {

        Permission permission = getPermissionInstance(permissionName);

        if (permission == null)

        {

            // unknown permission -> it is denied

            return 0;

        }

        SecurityStorage storage = new SecurityStorage(iStorageSession);

        try

        {

            // resolve the given permission against the set of granted permissions

            Vector resolvedPermissions = PermissionResolver.resolvePermission(

                                             storage.getStorageSession(), iAppUID, permission);

            if (resolvedPermissions == null)

            {

                // denied permission

                return 0;

            }

            // if the permission was resolved, check if granting it requires

            // user interaction

            for (int i=0; i<resolvedPermissions.size(); i++)

            {

                PolicyBasedPermissionImpl resolvedPermission =

                    (PolicyBasedPermissionImpl)resolvedPermissions.elementAt(i);

                if (resolvedPermission.getUserSecuritySettings() != null)

                {

                    // user permission: check the user settings

                    UserSecuritySettings settings = resolvedPermission

                                                    .getUserSecuritySettings();

                    switch (settings.getCurrentInteractionMode())

                    {

                    case UserSecuritySettings.ONESHOT_INTERACTION_MODE:

                        // requires user interaction

                        return -1;

                    case UserSecuritySettings.NO_INTERACTION_MODE:

                        // denied

                        return 0;

                    case UserSecuritySettings.BLANKET_INTERACTION_MODE:

                        // if prompt in blanket mode was shown then return 1

                        // otherwise return -1

                        boolean blanketPromptShown = storage

                                                     .readUserSecuritySettingsPromptFlag(

                                                         iAppUID, settings.getName());

                        return (blanketPromptShown ? 1 : -1);

                    case UserSecuritySettings.SESSION_INTERACTION_MODE:

                        return iSecurityPromptHandler

                               .getSessionPromptStatus(settings.getName());

                    }

                }

            }

        }

        finally

        {

            storage.close();

        }

        return 1;

    }

    /**

     * Checks if the calling entity (e.g. MIDlet suite) has access to

     * functionality protected by given permission (identified by name).

     *

     * @param permissionName Name of the permission to be checked

     * @return               true if the permission is allowed

     *                       false if the permission is denied

     */

    public boolean isPermissionAllowed(String permissionName)

    {

        Permission permission = getPermissionInstance(permissionName);

        if (permission == null)

        {

            // unknown permission -> it is denied

            return false;

        }

        try

        {

            checkPermission(permission);

        }

        catch (AccessControlException e)

        {

            return false;

        }

        return true;

    }

    public AccessControllerImpl(StorageSession aStorageSession, Uid aAppSuiteUid, String aAppName)

    {

        init(aStorageSession, aAppSuiteUid, aAppName);

    }

    /**

     * Closes the storage session

     */

    public void destroy()

    {

        iSecurityPromptHandler.destroy();

    }

    /**

     * Does the initialization: initializes the prompt handler and and

     * the storage

     */

    private void init(StorageSession aStorageSession, Uid appUID, String appName)

    {

        this.iAppUID = appUID;

        this.iStorageSession = aStorageSession;

        iSecurityPromptHandler = new SecurityPromptHandler(appName,

                GeneralSecuritySettings.getSecurityWarningsMode(iStorageSession, appUID));

    }

    private Vector queryPermission(Permission p, SecurityStorage storage)

    {

        // resolve the given permission against the set of granted permissions

        Vector resolvedPermissions =

            PermissionResolver.resolvePermission(

                storage.getStorageSession(), iAppUID, p);

        // if permission not resovled FAIL

        if (resolvedPermissions == null)

        {

            fail(p);

        }

        return resolvedPermissions;

    }

    /**

     * Handles the user settings by delegating the prompt handler to handle

     * the settings and stores the result as the new settings

     */

    private void handleUserPermission(

        Permission checkedPermission,

        SecurityStorage storage)

    {

        UserSecuritySettings settings = resolvedPermission

                                        .getUserSecuritySettings();

        // check if the settings are set to NO

        if (settings.getCurrentInteractionMode()

                == UserSecuritySettings.NO_INTERACTION_MODE)

        {

            fail(checkedPermission);

        }

        // check if the permission explicitly denies showing of the prompt

        if (!resolvedPermission.getPromptDetails().isSecurityPromptNeeed(

                    settings.getCurrentInteractionMode()))

        {

            // no sense in going further

            return;

        }

        boolean OFF = false;

        boolean ON = true;

        // "blanket" mode MUST prompt the user only once

        // on or before the first invocation of the API or function protected.

        boolean blanketPromptShown = storage

                                     .readUserSecuritySettingsPromptFlag(iAppUID, settings.getName());

        // give it to PromptHandler

        UserSecuritySettings newSettings;

        try

        {

            newSettings = iSecurityPromptHandler.handleUserPermission(

                              resolvedPermission, blanketPromptShown);

        }

        catch (UserCancelException e)

        {

            // add the AccessControlException as embedded exception

            throw new UserCancelException(

                e.getMessage(),

                new java.security.AccessControlException(

                    "Permission " + checkedPermission + " not allowed"));

        }

        // if settings have not changed, still do one check on the current

        // interaction mode: if it's blanket, mark down that the prompt in

        // blanket mode was shown and then simply return

        if (newSettings.equals(settings))

        {

            if (newSettings.getCurrentInteractionMode()

                    == UserSecuritySettings.BLANKET_INTERACTION_MODE

                    && !blanketPromptShown)

            {

                storage.writeUserSecuritySettingsPromptFlag(iAppUID,

                        settings.getName(), ON);

            }

            return;

        }

        if (newSettings.getCurrentInteractionMode()

                == UserSecuritySettings.NO_INTERACTION_MODE)

        {

            // denying from runtime prompts will not change the settings

            // to NO -> it is always a onetime deny (this has been chosen

            // for a better user experience)

            fail(checkedPermission);

        }

        if (settings.getCurrentInteractionMode()

                == UserSecuritySettings.BLANKET_INTERACTION_MODE

                && newSettings.getCurrentInteractionMode()

                != UserSecuritySettings.BLANKET_INTERACTION_MODE)

        {

            // if mode is changed from blanket to something else than blanket,

            // reset the flag indicating if prompting happened in blanket mode

            blanketPromptShown = OFF;

        }

        else if (newSettings.getCurrentInteractionMode()

                 == UserSecuritySettings.BLANKET_INTERACTION_MODE)

        {

            // if mode is changed to blanket, set the flag indicating that

            // prompt happened in blanket mode, since the change to blanket

            // mode was made via a prompt

            blanketPromptShown = ON;

        }

        // write the new settings to storage

        storage.writeUserSecuritySettings(iAppUID, newSettings.getName(),

                                          newSettings.getCurrentInteractionMode(), blanketPromptShown);

        // inform the PermissionResolver that the settings have changed

        PermissionResolver.settingsChanged(iAppUID, newSettings);

        /* Uncomment if the mutual exclusive rules are to be applied in runtime security prompts

        // apply the mutually exclusive rules

        applyMutualExclusiveRules(storage, newSettings);

        */

    }

    private Permission getPermissionInstance(String permissionName)

    {

        if (permissionName != null)

        {

            MIDPPermission internalPermission = PermissionMappingTable.get(

                                                    permissionName);

            if (internalPermission == null)

            {

                internalPermission = SecurityExtensionsReader.getExtPermission(permissionName);

            }

            if (internalPermission != null)

            {

                // make an instance of the internal permission

                try

                {

                    return (Permission)ClassInstantiator.newInstance(

                               internalPermission.getName(),

                               internalPermission.getTarget(),

                               internalPermission.getActionList());

                }

                catch (InstantiationException e)

                {

                    // fall-through

                }

            }

        }

        // fall-through

        return null;

    }

    private void fail(Permission p)

    {

        throw new java.security.AccessControlException(

            "Permission " + p + " not allowed");

    }

    private void applyMutualExclusiveRules(SecurityStorage storage, UserSecuritySettings settings)

    {

        // Rule1: if the settings belongs to list 1, change the settings

        //        to Session or Oneshot or No for all the settings belonging

        //        to list 2

        // Rule2: if the settings belongs to list 2, change the settings

        //        to Session or Oneshot or No for all the settings belonging

        //        to list 1

        // where

        //        list 1: Application Auto Invocation

        //        list 2: Net Access

        boolean settings_in_list1 = (settings.getName().equalsIgnoreCase(

                                         UserSecuritySettings.APPLICATION_AUTO_INVOCATION_SETTINGS));

        boolean settings_in_list2 = (settings.getName().equalsIgnoreCase(

                                         UserSecuritySettings.NET_ACCESS_SETTINGS));

        if (settings.getCurrentInteractionMode()

                != UserSecuritySettings.BLANKET_INTERACTION_MODE

                || (settings_in_list1 == false && settings_in_list2 == false))

        {

            // not applicable

            return;

        }

        String mutualExclusiveSettingsName = (settings_in_list1

                                              ? UserSecuritySettings.NET_ACCESS_SETTINGS

                                              : UserSecuritySettings.APPLICATION_AUTO_INVOCATION_SETTINGS);

        UserSecuritySettings[] allSettings =

            storage.readUserSecuritySettings(iAppUID);

        for (int i=0; i<allSettings.length; i++)

        {

            if (allSettings[i].getName().equals(mutualExclusiveSettingsName)

                    && allSettings[i].getCurrentInteractionMode()

                    == UserSecuritySettings.BLANKET_INTERACTION_MODE)

            {

                // change the mutualExclusiveSettings to either

                // Session or Oneshot or No

                int mutualExclusiveSettingsIntractionMode;

                if (allSettings[i].isInteractionModeAllowed(

                            UserSecuritySettings.SESSION_INTERACTION_MODE))

                {

                    mutualExclusiveSettingsIntractionMode =

                        UserSecuritySettings.SESSION_INTERACTION_MODE;

                }

                else if (allSettings[i].isInteractionModeAllowed(

                             UserSecuritySettings.ONESHOT_INTERACTION_MODE))

                {

                    mutualExclusiveSettingsIntractionMode =

                        UserSecuritySettings.ONESHOT_INTERACTION_MODE;

                }

                else

                {

                    mutualExclusiveSettingsIntractionMode =

                        UserSecuritySettings.NO_INTERACTION_MODE;

                }

                storage.writeUserSecuritySettings(iAppUID,

                                                  mutualExclusiveSettingsName,

                                                  mutualExclusiveSettingsIntractionMode);

                // inform the PermissionResolver that the settings have changed

                PermissionResolver.settingsChanged(iAppUID, allSettings[i]);

            }

        }

    }

}