add basic handling in dynamic values for terraform resources

checkov/terraform/checks/resource/base_resource_check.py

@@ -13,6 +13,7 @@ def __init__(self, name, id, categories, supported_resources):
         resource_registry.register(self)
 
     def scan_entity_conf(self, conf, entity_type):
+        self.handle_dynamic_values(conf)
         return self.scan_resource_conf(conf, entity_type)
 
     @multi_signature()
@@ -32,3 +33,8 @@ def wrapper(self, conf, entity_type=None):
             return wrapped(self, conf)
 
         return wrapper
+
+    def handle_dynamic_values(self, conf):
+        for dynamic_element in conf.get("dynamic", []):
+            for element_name in dynamic_element.keys():
+                conf[element_name] = dynamic_element[element_name].get('content', [])

checkov/terraform/checks/resource/base_resource_negative_value_check.py

@@ -13,6 +13,8 @@ def __init__(self, name, id, categories, supported_resources):
         super().__init__(name=name, id=id, categories=categories, supported_resources=supported_resources)
 
     def scan_resource_conf(self, conf):
+        self.handle_dynamic_values(conf)
+
         excluded_key = self.get_excluded_key()
         if excluded_key is not None:
             if dpath.search(conf, excluded_key) != {}:

checkov/terraform/checks/resource/base_resource_value_check.py

@@ -40,6 +40,7 @@ def _is_nesting_key(inspected_attributes, key):
         return any([x in key for x in inspected_attributes])
 
     def scan_resource_conf(self, conf):
+        self.handle_dynamic_values(conf)
         inspected_key = self.get_inspected_key()
         expected_values = self.get_expected_values()
         if dpath.search(conf, inspected_key) != {}:

tests/terraform/checks/resource/aws/test_S3Encryption.py

@@ -2,8 +2,8 @@
 
 import hcl2
 
-from checkov.terraform.checks.resource.aws.S3Encryption import check
 from checkov.common.models.enums import CheckResult
+from checkov.terraform.checks.resource.aws.S3Encryption import check
 
 
 class TestS3Encryption(unittest.TestCase):
@@ -56,5 +56,45 @@ def test_success_oneline(self):
         scan_result = check.scan_resource_conf(conf=resource_conf)
         self.assertEqual(CheckResult.PASSED, scan_result)
 
+    def test_dynamic_value(self):
+        hcl_res = hcl2.loads("""
+            resource "aws_s3_bucket" "default" {
+              count         = local.enabled ? 1 : 0
+              bucket        = module.this.id
+              acl           = "private"
+              force_destroy = var.force_destroy
+              tags          = module.this.tags
+            
+              versioning {
+                enabled = var.versioning_enabled
+              }
+            
+              dynamic "logging" {
+                for_each = var.access_log_bucket_name != "" ? [1] : []
+                content {
+                  target_bucket = var.access_log_bucket_name
+                  target_prefix = "logs/${module.this.id}/"
+                }
+              }
+            
+              dynamic "server_side_encryption_configuration" {
+                for_each = var.s3_bucket_encryption_enabled ? [1] : []
+            
+                content {
+                  rule {
+                    apply_server_side_encryption_by_default {
+                      sse_algorithm = "AES256"
+                    }
+                  }
+                }
+              }
+            
+            }
+        """)
+        resource_conf = hcl_res['resource'][0]['aws_s3_bucket']['default']
+        scan_result = check.scan_resource_conf(conf=resource_conf)
+        self.assertEqual(CheckResult.PASSED, scan_result)
+
+
 if __name__ == '__main__':
     unittest.main()