/* This work is licensed under a Creative Commons CCZero 1.0 Universal License.

 * See http://creativecommons.org/publicdomain/zero/1.0/ for more information.

 *

 *    Copyright 2016-2017 (c) Fraunhofer IOSB (Author: Julius Pfrommer)

 *    Copyright 2017 (c) Stefan Profanter, fortiss GmbH

 *    Copyright 2019 (c) HMS Industrial Networks AB (Author: Jonas Green)

 */

#include <open62541/plugin/accesscontrol_default.h>

#ifdef UA_ENABLE_RBAC

/* Internal RBAC API; not declared in public plugin headers. */

UA_StatusCode

UA_Server_getEffectivePermissions(UA_Server *server,

                                  const UA_NodeId *sessionId,

                                  const UA_NodeId *nodeId,

                                  UA_PermissionType *effectivePermissions);

#endif

/* Example access control management. Anonymous and username / password login.

 * The access rights are maximally permissive.

 *

 * FOR PRODUCTION USE, THIS EXAMPLE PLUGIN SHOULD BE REPLACED WITH LESS

 * PERMISSIVE ACCESS CONTROL.

 *

 * For TransferSubscriptions, we check whether the transfer happens between

 * Sessions for the same user. */

typedef struct {

    UA_Boolean allowAnonymous;

    size_t usernamePasswordLoginSize;

    UA_UsernamePasswordLogin *usernamePasswordLogin;

    UA_UsernamePasswordLoginCallback loginCallback;

    void *loginContext;

    UA_CertificateGroup verifyX509;

} AccessControlContext;

#define ANONYMOUS_POLICY "open62541-anonymous-policy"

#define CERTIFICATE_POLICY "open62541-certificate-policy"

#define USERNAME_POLICY "open62541-username-policy"

/************************/

/* Access Control Logic */

/************************/

static UA_StatusCode

activateSession_default(UA_Server *server, UA_AccessControl *ac,

                        const UA_EndpointDescription *endpointDescription,

                        const UA_ByteString *secureChannelRemoteCertificate,

                        const UA_NodeId *sessionId,

                        const UA_ExtensionObject *userIdentityToken,

                        void **sessionContext) {

    AccessControlContext *context = (AccessControlContext*)ac->context;

    /* The empty token is interpreted as anonymous */

    UA_AnonymousIdentityToken anonToken;

    UA_ExtensionObject tmpIdentity;

    if(userIdentityToken->encoding == UA_EXTENSIONOBJECT_ENCODED_NOBODY) {

        UA_AnonymousIdentityToken_init(&anonToken);

        UA_ExtensionObject_init(&tmpIdentity);

        UA_ExtensionObject_setValueNoDelete(&tmpIdentity,

                                            &anonToken,

                                            &UA_TYPES[UA_TYPES_ANONYMOUSIDENTITYTOKEN]);

        userIdentityToken = &tmpIdentity;

    }

    /* Could the token be decoded? */

    if(userIdentityToken->encoding < UA_EXTENSIONOBJECT_DECODED)

        return UA_STATUSCODE_BADIDENTITYTOKENINVALID;

    const UA_DataType *tokenType = userIdentityToken->content.decoded.type;

    if(tokenType == &UA_TYPES[UA_TYPES_ANONYMOUSIDENTITYTOKEN]) {

        /* Anonymous login */

        if(!context->allowAnonymous)

            return UA_STATUSCODE_BADIDENTITYTOKENINVALID;

        if(context->loginCallback) {

            UA_StatusCode res =

                context->loginCallback(&UA_STRING_NULL, &UA_BYTESTRING_NULL,

                                       context->usernamePasswordLoginSize,

                                       context->usernamePasswordLogin,

                                       sessionContext, context->loginContext);

            if(res != UA_STATUSCODE_GOOD)

                return UA_STATUSCODE_BADUSERACCESSDENIED;

        }

    } else if(tokenType == &UA_TYPES[UA_TYPES_USERNAMEIDENTITYTOKEN]) {

        /* Username and password */

        const UA_UserNameIdentityToken *userToken = (UA_UserNameIdentityToken*)

            userIdentityToken->content.decoded.data;

        /* Empty username and password */

        if(userToken->userName.length == 0 && userToken->password.length == 0)

            return UA_STATUSCODE_BADIDENTITYTOKENINVALID;

        /* Try to match username/pw */

        if(context->loginCallback) {

            /* Configured callback */

            UA_StatusCode res =

                context->loginCallback(&userToken->userName, &userToken->password,

                                       context->usernamePasswordLoginSize,

                                       context->usernamePasswordLogin,

                                       sessionContext, context->loginContext);

            if(res != UA_STATUSCODE_GOOD)

                return UA_STATUSCODE_BADUSERACCESSDENIED;

        } else {

            /* Compare against the configured list  */

            UA_Boolean match = false;

            for(size_t i = 0; i < context->usernamePasswordLoginSize; i++) {

                UA_UsernamePasswordLogin *upl = &context->usernamePasswordLogin[i];

                if(!UA_String_equal(&userToken->userName, &upl->username))

                   continue;

                if(userToken->password.length != upl->password.length)

                    continue;

                if(!UA_constantTimeEqual(userToken->password.data,

                                         upl->password.data,

                                         upl->password.length))

                    continue;

                match = true;

                break;

            }

            if(!match)

                return UA_STATUSCODE_BADUSERACCESSDENIED;

        }

    } else if(tokenType == &UA_TYPES[UA_TYPES_X509IDENTITYTOKEN]) {

        /* x509 certificate was already validated against the sessionPKI in the

         * server */

    } else {

        /* Unsupported token type */

        return UA_STATUSCODE_BADIDENTITYTOKENINVALID;

    }

    /* Store the endpoint's SecurityPolicyUri as a custom session attribute.

     * This is needed later in allowTransferSubscription_default to determine

     * whether the session was established over a secure channel. */

    if(endpointDescription) {

        UA_Variant spUri;

        UA_Variant_setScalar(&spUri, (void*)(uintptr_t)&endpointDescription->securityPolicyUri,

                             &UA_TYPES[UA_TYPES_STRING]);

        UA_Server_setSessionAttribute(server, sessionId,

                                      UA_QUALIFIEDNAME(0, "channelSecurityPolicyUri"),

                                      &spUri);

    }

    return UA_STATUSCODE_GOOD;

}

static void

closeSession_default(UA_Server *server, UA_AccessControl *ac,

                     const UA_NodeId *sessionId, void *sessionContext) {

}

/* Map RBAC PermissionType bits to the node's UserWriteMask.

 *

 * OPC UA Part 3, Table 8 defines three separate permission bits that

 * control attribute writing:

 *   - WriteAttribute  -> all WriteMask bits EXCEPT RolePermissions

 *                        and Historizing (the "catch-all" permission)

 *   - WriteRolePermissions -> UA_WRITEMASK_ROLEPERMISSIONS (bit 23)

 *   - WriteHistorizing     -> UA_WRITEMASK_HISTORIZING    (bit 9)

 *

 * 0xFFFFFFFF effectivePerms means "no RBAC restrictions configured" for

 * the node, so we return all-bits-set (fully permissive). */

static UA_UInt32

getUserRightsMask_default(UA_Server *server, UA_AccessControl *ac,

                          const UA_NodeId *sessionId, void *sessionContext,

                          const UA_NodeId *nodeId, void *nodeContext) {

#ifdef UA_ENABLE_RBAC

    UA_PermissionType effectivePerms = 0;

    UA_StatusCode res = UA_Server_getEffectivePermissions(server, sessionId,

                                                          nodeId, &effectivePerms);

    if(res != UA_STATUSCODE_GOOD || effectivePerms == 0xFFFFFFFF)

        return 0xFFFFFFFF;

    UA_UInt32 userWriteMask = 0;

    if(effectivePerms & UA_PERMISSIONTYPE_WRITEATTRIBUTE) {

        /* Grant all attribute-write bits, then carve out the two that

         * have their own dedicated permission bits. */

        userWriteMask = 0xFFFFFFFF;

        userWriteMask &= ~UA_WRITEMASK_ROLEPERMISSIONS;

        userWriteMask &= ~UA_WRITEMASK_HISTORIZING;

    }

    if(effectivePerms & UA_PERMISSIONTYPE_WRITEROLEPERMISSIONS)

        userWriteMask |= UA_WRITEMASK_ROLEPERMISSIONS;

    if(effectivePerms & UA_PERMISSIONTYPE_WRITEHISTORIZING)

        userWriteMask |= UA_WRITEMASK_HISTORIZING;

    return userWriteMask;

#else

    return 0xFFFFFFFF;

#endif

}

/* Map RBAC PermissionType bits to the Variable node's UserAccessLevel.

 *

 * OPC UA Part 3, Table 8 maps:

 *   - Read          -> ACCESSLEVELMASK_READ         (bit 0)

 *   - Write         -> ACCESSLEVELMASK_WRITE        (bit 1)

 *   - ReadHistory   -> ACCESSLEVELMASK_HISTORYREAD  (bit 2)

 *   - InsertHistory |

 *     ModifyHistory |

 *     DeleteHistory -> ACCESSLEVELMASK_HISTORYWRITE (bit 3)

 *

 * StatusWrite (bit 5) and TimestampWrite (bit 6) are not mapped from

 * RBAC permissions — they remain restricted unless the node has no

 * RBAC configuration (0xFFFFFFFF). */

static UA_Byte

getUserAccessLevel_default(UA_Server *server, UA_AccessControl *ac,

                           const UA_NodeId *sessionId, void *sessionContext,

                           const UA_NodeId *nodeId, void *nodeContext) {

#ifdef UA_ENABLE_RBAC

    UA_PermissionType effectivePerms = 0;

    UA_StatusCode res = UA_Server_getEffectivePermissions(server, sessionId,

                                                          nodeId, &effectivePerms);

    if(res != UA_STATUSCODE_GOOD || effectivePerms == 0xFFFFFFFF)

        return 0xFF;

    UA_Byte userAccessLevel = 0;

    if(effectivePerms & UA_PERMISSIONTYPE_READ)

        userAccessLevel |= UA_ACCESSLEVELMASK_READ;

    if(effectivePerms & UA_PERMISSIONTYPE_WRITE)

        userAccessLevel |= UA_ACCESSLEVELMASK_WRITE;

    if(effectivePerms & UA_PERMISSIONTYPE_READHISTORY)

        userAccessLevel |= UA_ACCESSLEVELMASK_HISTORYREAD;

    if(effectivePerms & (UA_PERMISSIONTYPE_INSERTHISTORY |

                         UA_PERMISSIONTYPE_MODIFYHISTORY |

                         UA_PERMISSIONTYPE_DELETEHISTORY))

        userAccessLevel |= UA_ACCESSLEVELMASK_HISTORYWRITE;

    return userAccessLevel;

#else

    return 0xFF;

#endif

}

/* OPC UA Part 3, Table 8: Call permission -> UserExecutable attribute. */

static UA_Boolean

getUserExecutable_default(UA_Server *server, UA_AccessControl *ac,

                          const UA_NodeId *sessionId, void *sessionContext,

                          const UA_NodeId *methodId, void *methodContext) {

#ifdef UA_ENABLE_RBAC

    UA_PermissionType effectivePerms = 0;

    UA_StatusCode res = UA_Server_getEffectivePermissions(server, sessionId,

                                                          methodId, &effectivePerms);

    if(res != UA_STATUSCODE_GOOD || effectivePerms == 0xFFFFFFFF)

        return true;

    return (effectivePerms & UA_PERMISSIONTYPE_CALL) != 0;

#else

    return true;

#endif

}

/* Call permission is checked on both the object and the method node.

 * Both must grant CALL for the method invocation to be allowed. */

static UA_Boolean

getUserExecutableOnObject_default(UA_Server *server, UA_AccessControl *ac,

                                  const UA_NodeId *sessionId, void *sessionContext,

                                  const UA_NodeId *methodId, void *methodContext,

                                  const UA_NodeId *objectId, void *objectContext) {

#ifdef UA_ENABLE_RBAC

    UA_PermissionType objectPerms = 0;

    UA_StatusCode res = UA_Server_getEffectivePermissions(server, sessionId,

                                                          objectId, &objectPerms);

    if(res != UA_STATUSCODE_GOOD)

        return true;

    if(objectPerms != 0xFFFFFFFF && !(objectPerms & UA_PERMISSIONTYPE_CALL))

        return false;

    UA_PermissionType methodPerms = 0;

    res = UA_Server_getEffectivePermissions(server, sessionId,

                                            methodId, &methodPerms);

    if(res != UA_STATUSCODE_GOOD)

        return true;

    if(methodPerms != 0xFFFFFFFF && !(methodPerms & UA_PERMISSIONTYPE_CALL))

        return false;

    return true;

#else

    return true;

#endif

}

/* AddNode permission is checked on the parent node. */

static UA_Boolean

allowAddNode_default(UA_Server *server, UA_AccessControl *ac,

                     const UA_NodeId *sessionId, void *sessionContext,

                     const UA_AddNodesItem *item) {

#ifdef UA_ENABLE_RBAC

    UA_PermissionType effectivePerms = 0;

    UA_StatusCode res = UA_Server_getEffectivePermissions(server, sessionId,

                                                          &item->parentNodeId.nodeId,

                                                          &effectivePerms);

    if(res != UA_STATUSCODE_GOOD || effectivePerms == 0xFFFFFFFF)

        return true;

    return (effectivePerms & UA_PERMISSIONTYPE_ADDNODE) != 0;

#else

    return true;

#endif

}

/* AddReference permission is checked on the source node. */

static UA_Boolean

allowAddReference_default(UA_Server *server, UA_AccessControl *ac,

                          const UA_NodeId *sessionId, void *sessionContext,

                          const UA_AddReferencesItem *item) {

#ifdef UA_ENABLE_RBAC

    UA_PermissionType effectivePerms = 0;

    UA_StatusCode res = UA_Server_getEffectivePermissions(server, sessionId,

                                                          &item->sourceNodeId,

                                                          &effectivePerms);

    if(res != UA_STATUSCODE_GOOD || effectivePerms == 0xFFFFFFFF)

        return true;

    return (effectivePerms & UA_PERMISSIONTYPE_ADDREFERENCE) != 0;

#else

    return true;

#endif

}

/* DeleteNode permission is checked on the node itself. */

static UA_Boolean

allowDeleteNode_default(UA_Server *server, UA_AccessControl *ac,

                        const UA_NodeId *sessionId, void *sessionContext,

                        const UA_DeleteNodesItem *item) {

#ifdef UA_ENABLE_RBAC

    UA_PermissionType effectivePerms = 0;

    UA_StatusCode res = UA_Server_getEffectivePermissions(server, sessionId,

                                                          &item->nodeId,

                                                          &effectivePerms);

    if(res != UA_STATUSCODE_GOOD || effectivePerms == 0xFFFFFFFF)

        return true;

    return (effectivePerms & UA_PERMISSIONTYPE_DELETENODE) != 0;

#else

    return true;

#endif

}

/* RemoveReference permission is checked on the source node. */

static UA_Boolean

allowDeleteReference_default(UA_Server *server, UA_AccessControl *ac,

                             const UA_NodeId *sessionId, void *sessionContext,

                             const UA_DeleteReferencesItem *item) {

#ifdef UA_ENABLE_RBAC

    UA_PermissionType effectivePerms = 0;

    UA_StatusCode res = UA_Server_getEffectivePermissions(server, sessionId,

                                                          &item->sourceNodeId,

                                                          &effectivePerms);

    if(res != UA_STATUSCODE_GOOD || effectivePerms == 0xFFFFFFFF)

        return true;

    return (effectivePerms & UA_PERMISSIONTYPE_REMOVEREFERENCE) != 0;

#else

    return true;

#endif

}

/* OPC UA Part 3, Table 8: Browse permission. */

static UA_Boolean

allowBrowseNode_default(UA_Server *server, UA_AccessControl *ac,

                        const UA_NodeId *sessionId, void *sessionContext,

                        const UA_NodeId *nodeId, void *nodeContext) {

#ifdef UA_ENABLE_RBAC

    UA_PermissionType effectivePerms = 0;

    UA_StatusCode res = UA_Server_getEffectivePermissions(server, sessionId,

                                                          nodeId, &effectivePerms);

    if(res != UA_STATUSCODE_GOOD || effectivePerms == 0xFFFFFFFF)

        return true;

    return (effectivePerms & UA_PERMISSIONTYPE_BROWSE) != 0;

#else

    return true;

#endif

}

#ifdef UA_ENABLE_SUBSCRIPTIONS

static UA_Boolean

allowCreateSubscription_default(UA_Server *server, UA_AccessControl *ac,

                                const UA_NodeId *sessionId, void *sessionContext) {

    return true;

}

static UA_Boolean

allowTransferSubscription_default(UA_Server *server, UA_AccessControl *ac,

                                  const UA_NodeId *oldSessionId, void *oldSessionContext,

                                  const UA_NodeId *newSessionId, void *newSessionContext) {

    if(!oldSessionId)

        return false;

    /* Get clientUserId for both sessions */

    UA_Variant session1UserId;

    UA_Variant_init(&session1UserId);

    UA_Server_getSessionAttribute(server, oldSessionId,

                                  UA_QUALIFIEDNAME(0, "clientUserId"),

                                  &session1UserId);

    UA_Variant session2UserId;

    UA_Variant_init(&session2UserId);

    UA_Server_getSessionAttribute(server, newSessionId,

                                  UA_QUALIFIEDNAME(0, "clientUserId"),

                                  &session2UserId);

    /* clientUserId is always a String type */

    UA_Boolean result = false;

    if(session1UserId.type == &UA_TYPES[UA_TYPES_STRING] &&

       session2UserId.type == &UA_TYPES[UA_TYPES_STRING]) {

        UA_String *userId1 = (UA_String*)session1UserId.data;

        UA_String *userId2 = (UA_String*)session2UserId.data;

        if(userId1->length == 0 && userId2->length == 0) {

            /* Both users are anonymous.

             * For anonymous users, the OPC UA specification requires

             * checking the ApplicationUri from the clientDescription

             * to verify that the same application is transferring the

             * subscription (e.g. after a network interruption or client

             * crash with reconnect on a different SecureChannel).

             *

             * Additionally, on unsecure connections (SecurityPolicy#None)

             * the ApplicationUri is not verified against a certificate,

             * so the transfer must be rejected. */

            /* First check: Both sessions must use a secure channel

             * (not SecurityPolicy#None). The securityPolicyUri was

             * stored as a session attribute during ActivateSession. */

            UA_Variant session1SpUri;

            UA_Variant_init(&session1SpUri);

            UA_Server_getSessionAttribute(server, oldSessionId,

                                          UA_QUALIFIEDNAME(0, "channelSecurityPolicyUri"),

                                          &session1SpUri);

            UA_Variant session2SpUri;

            UA_Variant_init(&session2SpUri);

            UA_Server_getSessionAttribute(server, newSessionId,

                                          UA_QUALIFIEDNAME(0, "channelSecurityPolicyUri"),

                                          &session2SpUri);

            UA_Boolean bothSecure = false;

            if(session1SpUri.type == &UA_TYPES[UA_TYPES_STRING] &&

               session2SpUri.type == &UA_TYPES[UA_TYPES_STRING]) {

                UA_String *spUri1 = (UA_String*)session1SpUri.data;

                UA_String *spUri2 = (UA_String*)session2SpUri.data;

                /* Reject if either session uses SecurityPolicy#None */

                if(!UA_String_equal(spUri1, &UA_SECURITY_POLICY_NONE_URI) &&

                   !UA_String_equal(spUri2, &UA_SECURITY_POLICY_NONE_URI)) {

                    bothSecure = true;

                }

            }

            UA_Variant_clear(&session1SpUri);

            UA_Variant_clear(&session2SpUri);

            /* Second check: If both channels are secure, compare the

             * ApplicationUri from the clientDescription. On secure

             * connections the ApplicationUri is validated against

             * the client certificate during CreateSession. */

            if(bothSecure) {

                UA_Variant session1Desc;

                UA_Variant_init(&session1Desc);

                UA_Server_getSessionAttribute(server, oldSessionId,

                                              UA_QUALIFIEDNAME(0, "clientDescription"),

                                              &session1Desc);

                UA_Variant session2Desc;

                UA_Variant_init(&session2Desc);

                UA_Server_getSessionAttribute(server, newSessionId,

                                              UA_QUALIFIEDNAME(0, "clientDescription"),

                                              &session2Desc);

                if(session1Desc.type == &UA_TYPES[UA_TYPES_APPLICATIONDESCRIPTION] &&

                   session2Desc.type == &UA_TYPES[UA_TYPES_APPLICATIONDESCRIPTION]) {

                    UA_ApplicationDescription *desc1 =

                        (UA_ApplicationDescription*)session1Desc.data;

                    UA_ApplicationDescription *desc2 =

                        (UA_ApplicationDescription*)session2Desc.data;

                    if(desc1->applicationUri.length > 0 &&

                       desc2->applicationUri.length > 0 &&

                       UA_String_equal(&desc1->applicationUri,

                                       &desc2->applicationUri)) {

                        result = true;

                    }

                }

                UA_Variant_clear(&session1Desc);

                UA_Variant_clear(&session2Desc);

            }

        } else if(UA_String_equal(userId1, userId2)) {

            /* Same authenticated user - allow transfer */

            result = true;

        }

    }

    UA_Variant_clear(&session1UserId);

    UA_Variant_clear(&session2UserId);

    return result;

}

#endif

#ifdef UA_ENABLE_HISTORIZING

/* OPC UA Part 3, Table 8: InsertHistory / ModifyHistory permissions.

 * INSERT -> InsertHistory, REPLACE/UPDATE -> ModifyHistory. */

static UA_Boolean

allowHistoryUpdateUpdateData_default(UA_Server *server, UA_AccessControl *ac,

                                     const UA_NodeId *sessionId, void *sessionContext,

                                     const UA_NodeId *nodeId,

                                     UA_PerformUpdateType performInsertReplace,

                                     const UA_DataValue *value) {

#ifdef UA_ENABLE_RBAC

    UA_PermissionType effectivePerms = 0;

    UA_StatusCode res = UA_Server_getEffectivePermissions(server, sessionId,

                                                          nodeId, &effectivePerms);

    if(res != UA_STATUSCODE_GOOD || effectivePerms == 0xFFFFFFFF)

        return true;

    if(performInsertReplace == UA_PERFORMUPDATETYPE_INSERT)

        return (effectivePerms & UA_PERMISSIONTYPE_INSERTHISTORY) != 0;

    else if(performInsertReplace == UA_PERFORMUPDATETYPE_REPLACE ||

            performInsertReplace == UA_PERFORMUPDATETYPE_UPDATE)

        return (effectivePerms & UA_PERMISSIONTYPE_MODIFYHISTORY) != 0;

    return true;

#else

    return true;

#endif

}

/* OPC UA Part 3, Table 8: DeleteHistory permission. */

static UA_Boolean

allowHistoryUpdateDeleteRawModified_default(UA_Server *server, UA_AccessControl *ac,

                                            const UA_NodeId *sessionId, void *sessionContext,

                                            const UA_NodeId *nodeId,

                                            UA_DateTime startTimestamp,

                                            UA_DateTime endTimestamp,

                                            bool isDeleteModified) {

#ifdef UA_ENABLE_RBAC

    UA_PermissionType effectivePerms = 0;

    UA_StatusCode res = UA_Server_getEffectivePermissions(server, sessionId,

                                                          nodeId, &effectivePerms);

    if(res != UA_STATUSCODE_GOOD || effectivePerms == 0xFFFFFFFF)

        return true;

    return (effectivePerms & UA_PERMISSIONTYPE_DELETEHISTORY) != 0;

#else

    return true;

#endif

}

#endif

/***************************************/

/* Create Delete Access Control Plugin */

/***************************************/

static void clear_default(UA_AccessControl *ac) {

    UA_Array_delete((void*)(uintptr_t)ac->userTokenPolicies,

                    ac->userTokenPoliciesSize,

                    &UA_TYPES[UA_TYPES_USERTOKENPOLICY]);

    ac->userTokenPolicies = NULL;

    ac->userTokenPoliciesSize = 0;

    AccessControlContext *context = (AccessControlContext*)ac->context;

    if (context) {

        for(size_t i = 0; i < context->usernamePasswordLoginSize; i++) {

            UA_String_clear(&context->usernamePasswordLogin[i].username);

            UA_ByteString_clear(&context->usernamePasswordLogin[i].password);

        }

        if(context->usernamePasswordLoginSize > 0)

            UA_free(context->usernamePasswordLogin);

        UA_free(ac->context);

        ac->context = NULL;

    }

}

UA_StatusCode

UA_AccessControl_default(UA_ServerConfig *config,

                         UA_Boolean allowAnonymous,

                         const UA_String *userTokenPolicyUri,

                         size_t usernamePasswordLoginSize,

                         const UA_UsernamePasswordLogin *usernamePasswordLogin) {

    UA_LOG_WARNING(config->logging, UA_LOGCATEGORY_SERVER,

                   "AccessControl: Unconfigured AccessControl. Users have all permissions.");

    UA_AccessControl *ac = &config->accessControl;

    if(ac->clear)

        ac->clear(ac);

    ac->clear = clear_default;

    ac->activateSession = activateSession_default;

    ac->closeSession = closeSession_default;

    ac->getUserRightsMask = getUserRightsMask_default;

    ac->getUserAccessLevel = getUserAccessLevel_default;

    ac->getUserExecutable = getUserExecutable_default;

    ac->getUserExecutableOnObject = getUserExecutableOnObject_default;

    ac->allowAddNode = allowAddNode_default;

    ac->allowAddReference = allowAddReference_default;

    ac->allowBrowseNode = allowBrowseNode_default;

#ifdef UA_ENABLE_SUBSCRIPTIONS

    ac->allowCreateSubscription = allowCreateSubscription_default;

    ac->allowTransferSubscription = allowTransferSubscription_default;

#endif

#ifdef UA_ENABLE_HISTORIZING

    ac->allowHistoryUpdateUpdateData = allowHistoryUpdateUpdateData_default;

    ac->allowHistoryUpdateDeleteRawModified = allowHistoryUpdateDeleteRawModified_default;

#endif

    ac->allowDeleteNode = allowDeleteNode_default;

    ac->allowDeleteReference = allowDeleteReference_default;

    AccessControlContext *context = (AccessControlContext*)

            UA_malloc(sizeof(AccessControlContext));

    if(!context)

        return UA_STATUSCODE_BADOUTOFMEMORY;

    memset(context, 0, sizeof(AccessControlContext));

    ac->context = context;

    /* Allow anonymous? */

    context->allowAnonymous = allowAnonymous;

    if(allowAnonymous) {

        UA_LOG_INFO(config->logging, UA_LOGCATEGORY_SERVER,

                    "AccessControl: Anonymous login is enabled");

    }

    /* Copy username/password to the access control plugin */

    if(usernamePasswordLoginSize > 0) {

        context->usernamePasswordLogin = (UA_UsernamePasswordLogin*)

            UA_malloc(usernamePasswordLoginSize * sizeof(UA_UsernamePasswordLogin));

        if(!context->usernamePasswordLogin)

            return UA_STATUSCODE_BADOUTOFMEMORY;

        context->usernamePasswordLoginSize = usernamePasswordLoginSize;

        for(size_t i = 0; i < usernamePasswordLoginSize; i++) {

            UA_String_copy(&usernamePasswordLogin[i].username,

                           &context->usernamePasswordLogin[i].username);

            UA_ByteString_copy(&usernamePasswordLogin[i].password,

                           &context->usernamePasswordLogin[i].password);

        }

    }

    size_t numOfPolcies = 1;

    if(!userTokenPolicyUri) {

        if(config->securityPoliciesSize > 0)

            numOfPolcies = config->securityPoliciesSize;

        else {

            UA_LOG_WARNING(config->logging, UA_LOGCATEGORY_SERVER,

                           "No security policies defined for the secure channel.");

            return UA_STATUSCODE_BADINTERNALERROR;

        }

    }

    /* Set the allowed policies */

    size_t policies = 0;

    if(allowAnonymous)

        policies++;

    if(usernamePasswordLoginSize > 0)

        policies++;

    if(config->sessionPKI.verifyCertificate)

        policies++;

    ac->userTokenPoliciesSize = 0;

    ac->userTokenPolicies = (UA_UserTokenPolicy *)

        UA_Array_new(policies * numOfPolcies, &UA_TYPES[UA_TYPES_USERTOKENPOLICY]);

    if(!ac->userTokenPolicies)

        return UA_STATUSCODE_BADOUTOFMEMORY;

    ac->userTokenPoliciesSize = policies * numOfPolcies;

    if(policies == 0) {

        UA_LOG_WARNING(config->logging, UA_LOGCATEGORY_SERVER,

                       "No allowed policies set.");

        return UA_STATUSCODE_GOOD;

    }

    const UA_String *utpUri = NULL;

    policies = 0;

    for(size_t i = 0; i < numOfPolcies; i++) {

        if(userTokenPolicyUri) {

            utpUri = userTokenPolicyUri;

        } else {

            utpUri = &config->securityPolicies[i].policyUri;

        }

        if(allowAnonymous) {

            ac->userTokenPolicies[policies].tokenType = UA_USERTOKENTYPE_ANONYMOUS;

            ac->userTokenPolicies[policies].policyId = UA_STRING_ALLOC(ANONYMOUS_POLICY);

            UA_String_copy(utpUri,

                               &ac->userTokenPolicies[policies].securityPolicyUri);

            policies++;

        }

        if(config->sessionPKI.verifyCertificate) {

            ac->userTokenPolicies[policies].tokenType = UA_USERTOKENTYPE_CERTIFICATE;

            ac->userTokenPolicies[policies].policyId = UA_STRING_ALLOC(CERTIFICATE_POLICY);

#if UA_LOGLEVEL <= 400

            if(UA_String_equal(utpUri, &UA_SECURITY_POLICY_NONE_URI)) {

                UA_LOG_WARNING(config->logging, UA_LOGCATEGORY_SERVER,

                               "x509 Certificate Authentication configured, "

                               "but no encrypting SecurityPolicy. "

                               "This can leak credentials on the network.");

            }

#endif

            UA_String_copy(utpUri,

                               &ac->userTokenPolicies[policies].securityPolicyUri);

            policies++;

        }

        if(usernamePasswordLoginSize > 0) {

            ac->userTokenPolicies[policies].tokenType = UA_USERTOKENTYPE_USERNAME;

            ac->userTokenPolicies[policies].policyId = UA_STRING_ALLOC(USERNAME_POLICY);

#if UA_LOGLEVEL <= 400

            if(UA_String_equal(utpUri, &UA_SECURITY_POLICY_NONE_URI)) {

                UA_LOG_WARNING(config->logging, UA_LOGCATEGORY_SERVER,

                               "Username/Password Authentication configured, "

                               "but no encrypting SecurityPolicy. "

                               "This can leak credentials on the network.");

            }

#endif

            UA_String_copy(utpUri,

                               &ac->userTokenPolicies[policies].securityPolicyUri);

            policies++;

        }

    }

    return UA_STATUSCODE_GOOD;

}

UA_StatusCode

UA_AccessControl_defaultWithLoginCallback(UA_ServerConfig *config,

                                          UA_Boolean allowAnonymous,

                                          const UA_String *userTokenPolicyUri,

                                          size_t usernamePasswordLoginSize,

                                          const UA_UsernamePasswordLogin *usernamePasswordLogin,

                                          UA_UsernamePasswordLoginCallback loginCallback,

                                          void *loginContext) {

    AccessControlContext *context;

    UA_StatusCode sc =

        UA_AccessControl_default(config, allowAnonymous, userTokenPolicyUri,

                                 usernamePasswordLoginSize, usernamePasswordLogin);

    if(sc != UA_STATUSCODE_GOOD)

        return sc;

    context = (AccessControlContext *)config->accessControl.context;

    context->loginCallback = loginCallback;

    context->loginContext = loginContext;

    return UA_STATUSCODE_GOOD;

}