# ###################################
##       Rule Specification        ##
#####################################
# 
# Rule Identifier:
#   opensearch_fine_grained_access_control_enabled_check
# 
# Description:
#   This control checks whether Amazon OpenSearch Service domains have fine-grained access control enabled.
# 
# Reports on:
#   AWS::OpenSearchService::Domain
# 
# Evaluates:
#   AWS CloudFormation, AWS CloudFormation hook
# 
# Rule Parameters:
#   None
# 
# Scenarios:
#   Scenario: 1
#     Given: The input document is an AWS CloudFormation or CloudFormation hook document
#       And: The input document does not contain any OpenSearch Service domain resources
#      Then: SKIP
#   Scenario: 2
#     Given: The input document is an AWS CloudFormation or CloudFormation hook document
#       And: The input document contains an OpenSearch Service domain resource
#       And: 'AdvancedSecurityOptions' has not been provided
#      Then: FAIL
#   Scenario: 3
#     Given: The input document is an AWS CloudFormation or CloudFormation hook document
#       And: The input document contains an OpenSearch Service domain resource
#       And: 'AdvancedSecurityOptions' has been provided
#       And: 'Enabled' in 'AdvancedSecurityOptions' has not been provided or
#            has been provided and set to a value other than bool(true)
#       And: 'InternalUserDatabaseEnabled' in 'AdvancedSecurityOptions' has not been provided or provided and set to a
#             non boolean value
#       And: 'MasterUserOptions' in 'AdvancedSecurityOptions' has not been provided or provided and set to a value
#            other than a struct
#      Then: FAIL
#   Scenario: 4
#     Given: The input document is an AWS CloudFormation or CloudFormation hook document
#       And: The input document contains an OpenSearch Service domain resource
#       And: 'AdvancedSecurityOptions' has been provided
#       And: 'Enabled' in 'AdvancedSecurityOptions' has been provided and set to bool(true)
#       And: 'InternalUserDatabaseEnabled' in 'AdvancedSecurityOptions' has not been provided or provided and set to a
#             non boolean value
#       And: 'MasterUserOptions' in 'AdvancedSecurityOptions' has not been provided or provided and set to a value
#            other than a struct
#      Then: FAIL
#   Scenario: 5
#     Given: The input document is an AWS CloudFormation or CloudFormation hook document
#       And: The input document contains an OpenSearch Service domain resource
#       And: 'AdvancedSecurityOptions' has been provided
#       And: 'Enabled' in 'AdvancedSecurityOptions' has been provided and set to bool(true)
#       And: 'InternalUserDatabaseEnabled' in 'AdvancedSecurityOptions' has been provided and set to a
#            boolean value
#       And: 'MasterUserOptions' in 'AdvancedSecurityOptions' has not been provided or provided and set to a value
#            other than a struct
#      Then: FAIL
#   Scenario: 6
#     Given: The input document is an AWS CloudFormation or CloudFormation hook document
#       And: The input document contains an OpenSearch Service domain resource
#       And: 'AdvancedSecurityOptions' has been provided
#       And: 'Enabled' in 'AdvancedSecurityOptions' has been provided and set to bool(true)
#       And: 'InternalUserDatabaseEnabled' in 'AdvancedSecurityOptions' has not been provided or provided and set to a
#             non boolean value
#       And: 'MasterUserOptions' in 'AdvancedSecurityOptions' has been provided and set to a struct
#      Then: FAIL
#   Scenario: 7
#     Given: The input document is an AWS CloudFormation or CloudFormation hook document
#       And: The input document contains an OpenSearch Service domain resource
#       And: 'AdvancedSecurityOptions' has been provided
#       And: 'Enabled' in 'AdvancedSecurityOptions' has been provided and set to bool(true)
#       And: 'InternalUserDatabaseEnabled' in 'AdvancedSecurityOptions' has been provided and set to a
#            boolean value
#       And: 'MasterUserOptions' in 'AdvancedSecurityOptions' has been provided and set to a struct
#      Then: PASS

#
# Constants
#
let OPENSEARCH_SERVICE_DOMAIN_TYPE = "AWS::OpenSearchService::Domain"
let INPUT_DOCUMENT = this

#
# Assignments
#
let opensearch_service_domains = Resources.*[ Type == %OPENSEARCH_SERVICE_DOMAIN_TYPE ]

#
# Primary Rules
#
rule opensearch_fine_grained_access_control_enabled_check when is_cfn_template(%INPUT_DOCUMENT)
                                                               %opensearch_service_domains not empty {
    check(%opensearch_service_domains.Properties)
        <<
        [CT.OPENSEARCH.PR.15]: Require an Amazon OpenSearch Service domain to use fine-grained access control
        [FIX]: Within 'AdvancedSecurityOptions', set 'Enabled' to 'true', set 'InternalUserDatabaseEnabled' to 'true' or 'false', and set 'MasterUserOptions' with an options configuration for your master user.
        >>
}

rule opensearch_fine_grained_access_control_enabled_check when is_cfn_hook(%INPUT_DOCUMENT, %OPENSEARCH_SERVICE_DOMAIN_TYPE) {
    check(%INPUT_DOCUMENT.%OPENSEARCH_SERVICE_DOMAIN_TYPE.resourceProperties)
        <<
        [CT.OPENSEARCH.PR.15]: Require an Amazon OpenSearch Service domain to use fine-grained access control
        [FIX]: Within 'AdvancedSecurityOptions', set 'Enabled' to 'true', set 'InternalUserDatabaseEnabled' to 'true' or 'false', and set 'MasterUserOptions' with an options configuration for your master user.
        >>
}

#
# Parameterized Rules
#
rule check(opensearch_service_domain) {
    %opensearch_service_domain {
        # Scenario 2
        AdvancedSecurityOptions exists
        AdvancedSecurityOptions is_struct

        AdvancedSecurityOptions {
            # Scenarios 3, 4, 5, 6 and 7
            Enabled exists
            Enabled == true

            InternalUserDatabaseEnabled exists
            InternalUserDatabaseEnabled in [ true, false ]

            MasterUserOptions exists
            MasterUserOptions is_struct
        }
    }
}

#
# Utility Rules
#
rule is_cfn_template(doc) {
    %doc {
        AWSTemplateFormatVersion exists  or
        Resources exists
    }
}

rule is_cfn_hook(doc, RESOURCE_TYPE) {
    %doc.%RESOURCE_TYPE.resourceProperties exists
}