feat: refactor Function URL permissions (#3735)

Co-authored-by: jonathan Ifegunni <[email protected]>

Author: roger-zhangg

.cfnlintrc.yaml

@@ -1,6 +1,9 @@
 templates:
   - tests/translator/output/**/*.json
 ignore_templates:
+  - tests/translator/output/**/function_with_function_url_config.json
+  - tests/translator/output/**/function_with_function_url_config_and_autopublishalias.json
+  - tests/translator/output/**/function_with_function_url_config_without_cors_config.json
   - tests/translator/output/**/error_*.json # Fail by design
   - tests/translator/output/**/api_http_paths_with_if_condition.json
   - tests/translator/output/**/api_http_paths_with_if_condition_no_value_else_case.json

integration/resources/expected/single/basic_function_with_function_url_dual_auth.json

@@ -0,0 +1,22 @@
+[
+  {
+    "LogicalResourceId": "MyLambdaFunction",
+    "ResourceType": "AWS::Lambda::Function"
+  },
+  {
+    "LogicalResourceId": "MyLambdaFunctionUrl",
+    "ResourceType": "AWS::Lambda::Url"
+  },
+  {
+    "LogicalResourceId": "MyLambdaFunctionUrlPublicPermissions",
+    "ResourceType": "AWS::Lambda::Permission"
+  },
+  {
+    "LogicalResourceId": "MyLambdaFunctionURLInvokeAllowPublicAccess",
+    "ResourceType": "AWS::Lambda::Permission"
+  },
+  {
+    "LogicalResourceId": "MyLambdaFunctionRole",
+    "ResourceType": "AWS::IAM::Role"
+  }
+]

integration/resources/expected/single/basic_function_with_function_url_with_autopuplishalias_dual_auth.json

@@ -0,0 +1,30 @@
+[
+  {
+    "LogicalResourceId": "MyLambdaFunction",
+    "ResourceType": "AWS::Lambda::Function"
+  },
+  {
+    "LogicalResourceId": "MyLambdaFunctionRole",
+    "ResourceType": "AWS::IAM::Role"
+  },
+  {
+    "LogicalResourceId": "MyLambdaFunctionVersion",
+    "ResourceType": "AWS::Lambda::Version"
+  },
+  {
+    "LogicalResourceId": "MyLambdaFunctionAliaslive",
+    "ResourceType": "AWS::Lambda::Alias"
+  },
+  {
+    "LogicalResourceId": "MyLambdaFunctionUrlPublicPermissions",
+    "ResourceType": "AWS::Lambda::Permission"
+  },
+  {
+    "LogicalResourceId": "MyLambdaFunctionURLInvokeAllowPublicAccess",
+    "ResourceType": "AWS::Lambda::Permission"
+  },
+  {
+    "LogicalResourceId": "MyLambdaFunctionUrl",
+    "ResourceType": "AWS::Lambda::Url"
+  }
+]

integration/resources/templates/single/basic_function_with_function_url_dual_auth.yaml

@@ -0,0 +1,27 @@
+Resources:
+  MyLambdaFunction:
+    Type: AWS::Serverless::Function
+    Properties:
+      Handler: index.handler
+      Runtime: nodejs18.x
+      CodeUri: ${codeuri}
+      MemorySize: 128
+      FunctionUrlConfig:
+        AuthType: NONE
+        Cors:
+          AllowOrigins:
+          - https://foo.com
+          AllowMethods:
+          - POST
+          AllowCredentials: true
+          AllowHeaders:
+          - x-Custom-Header
+          ExposeHeaders:
+          - x-amzn-header
+          MaxAge: 10
+Outputs:
+  FunctionUrl:
+    Description: URL of the Lambda function
+    Value: !GetAtt MyLambdaFunctionUrl.FunctionUrl
+Metadata:
+  SamTransformTest: true

integration/resources/templates/single/basic_function_with_function_url_with_autopuplishalias_dual_auth.yaml

@@ -0,0 +1,28 @@
+Resources:
+  MyLambdaFunction:
+    Type: AWS::Serverless::Function
+    Properties:
+      Handler: index.handler
+      Runtime: nodejs18.x
+      CodeUri: ${codeuri}
+      MemorySize: 128
+      AutoPublishAlias: live
+      FunctionUrlConfig:
+        AuthType: NONE
+        Cors:
+          AllowOrigins:
+          - https://foo.com
+          AllowMethods:
+          - POST
+          AllowCredentials: true
+          AllowHeaders:
+          - x-Custom-Header
+          ExposeHeaders:
+          - x-amzn-header
+          MaxAge: 10
+Outputs:
+  FunctionUrl:
+    Description: URL of the Lambda function alias
+    Value: !GetAtt MyLambdaFunctionUrl.FunctionUrl
+Metadata:
+  SamTransformTest: true

integration/single/test_basic_function.py

@@ -130,6 +130,73 @@ def test_basic_function_with_url_config(self, file_name, qualifier):
         self.assertEqual(function_url_config["Cors"], cors_config)
         self._assert_invoke(lambda_client, function_name, qualifier, 200)
 
+    @parameterized.expand(
+        [
+            ("single/basic_function_with_function_url_dual_auth", None),
+            ("single/basic_function_with_function_url_with_autopuplishalias_dual_auth", "live"),
+        ]
+    )
+    @skipIf(current_region_does_not_support([LAMBDA_URL]), "Lambda Url is not supported in this testing region")
+    def test_basic_function_with_url_dual_auth(self, file_name, qualifier):
+        """
+        Creates a basic lambda function with Function Url with authtype: None
+        Verifies that 2 AWS::Lambda::Permission resources are created:
+        - lambda:InvokeFunctionUrl
+        - lambda:InvokeFunction with InvokedViaFunctionUrl: True
+        """
+        self.create_and_verify_stack(file_name)
+
+        # Get Lambda permissions
+        lambda_permissions = self.get_stack_resources("AWS::Lambda::Permission")
+
+        # Verify we have exactly 2 permissions
+        self.assertEqual(len(lambda_permissions), 2, "Expected exactly 2 Lambda permissions")
+
+        # Check for the expected permission logical IDs
+        invoke_function_url_permission = None
+        invoke_permission = None
+
+        for permission in lambda_permissions:
+            logical_id = permission["LogicalResourceId"]
+            if "MyLambdaFunctionUrlPublicPermissions" in logical_id:
+                invoke_function_url_permission = permission
+            elif "MyLambdaFunctionURLInvokeAllowPublicAccess" in logical_id:
+                invoke_permission = permission
+
+        # Verify both permissions exist
+        self.assertIsNotNone(invoke_function_url_permission, "Expected MyLambdaFunctionUrlPublicPermissions to exist")
+        self.assertIsNotNone(invoke_permission, "Expected MyLambdaFunctionURLInvokeAllowPublicAccess to exist")
+
+        # Get the function name and URL
+        function_name = self.get_physical_id_by_type("AWS::Lambda::Function")
+        lambda_client = self.client_provider.lambda_client
+
+        # Get the function URL configuration to verify auth type
+        function_url_config = (
+            lambda_client.get_function_url_config(FunctionName=function_name, Qualifier=qualifier)
+            if qualifier
+            else lambda_client.get_function_url_config(FunctionName=function_name)
+        )
+
+        # Verify the auth type is NONE
+        self.assertEqual(function_url_config["AuthType"], "NONE", "Expected AuthType to be NONE")
+
+        # Get the template to check for InvokedViaFunctionUrl property
+        cfn_client = self.client_provider.cfn_client
+        template = cfn_client.get_template(StackName=self.stack_name, TemplateStage="Processed")
+        template_body = template["TemplateBody"]
+
+        # Check if the InvokePermission has InvokedViaFunctionUrl: True
+        # This is a bit hacky but we don't have direct access to the resource properties
+        # We're checking if the string representation of the template contains this property
+        template_str = str(template_body)
+        self.assertIn("InvokedViaFunctionUrl", template_str, "Expected InvokedViaFunctionUrl property in the template")
+
+        # Get the function URL from stack outputs
+        function_url = self.get_stack_output("FunctionUrl")["OutputValue"]
+        # Invoke the function URL and verify the response
+        self._verify_get_request(function_url, self.FUNCTION_OUTPUT)
+
     @skipIf(current_region_does_not_support([CODE_DEPLOY]), "CodeDeploy is not supported in this testing region")
     def test_function_with_deployment_preference_alarms_intrinsic_if(self):
         self.create_and_verify_stack("single/function_with_deployment_preference_alarms_intrinsic_if")

samtranslator/model/lambda_.py

@@ -139,6 +139,7 @@ class LambdaPermission(Resource):
         "SourceArn": GeneratedProperty(),
         "EventSourceToken": GeneratedProperty(),
         "FunctionUrlAuthType": GeneratedProperty(),
+        "InvokedViaFunctionUrl": GeneratedProperty(),
     }
 
 

samtranslator/model/sam_resources.py

@@ -321,8 +321,12 @@ def to_cloudformation(self, **kwargs):  # type: ignore[no-untyped-def] # noqa: P
             lambda_url = self._construct_function_url(lambda_function, lambda_alias, self.FunctionUrlConfig)
             resources.append(lambda_url)
             url_permission = self._construct_url_permission(lambda_function, lambda_alias, self.FunctionUrlConfig)
-            if url_permission:
+            invoke_dual_auth_permission = self._construct_invoke_permission(
+                lambda_function, lambda_alias, self.FunctionUrlConfig
+            )
+            if url_permission and invoke_dual_auth_permission:
                 resources.append(url_permission)
+                resources.append(invoke_dual_auth_permission)
 
         self._validate_deployment_preference_and_add_update_policy(
             kwargs.get("deployment_preference_collection"),
@@ -332,7 +336,6 @@ def to_cloudformation(self, **kwargs):  # type: ignore[no-untyped-def] # noqa: P
             self.get_passthrough_resource_attributes(),
             feature_toggle,
         )
-
         event_invoke_policies: List[Dict[str, Any]] = []
         if self.EventInvokeConfig:
             function_name = lambda_function.logical_id
@@ -1225,9 +1228,13 @@ def _construct_url_permission(
         lambda_function : LambdaUrl
             Lambda Function resource
 
-        llambda_alias : LambdaAlias
+        lambda_alias : LambdaAlias
             Lambda Alias resource
 
+
+        function_url_config: Dict
+            Function url config used to create FURL
+
         Returns
         -------
         LambdaPermission
@@ -1249,6 +1256,47 @@ def _construct_url_permission(
         lambda_permission.FunctionUrlAuthType = auth_type
         return lambda_permission
 
+    def _construct_invoke_permission(
+        self, lambda_function: LambdaFunction, lambda_alias: Optional[LambdaAlias], function_url_config: Dict[str, Any]
+    ) -> Optional[LambdaPermission]:
+        """
+        Construct the lambda permission associated with the function invoke resource in a case
+        for public access when AuthType is NONE
+
+        Parameters
+        ----------
+        lambda_function : LambdaUrl
+            Lambda Function resource
+
+        lambda_alias : LambdaAlias
+            Lambda Alias resource
+
+        function_url_config: Dict
+            Function url config used to create FURL
+
+        Returns
+        -------
+        LambdaPermission
+            The lambda permission appended to a function that allow function invoke only from Function URL
+        """
+        # create lambda:InvokeFunction with InvokedViaFunctionUrl=True
+        auth_type = function_url_config.get("AuthType")
+
+        if auth_type not in ["NONE"] or is_intrinsic(function_url_config):
+            return None
+
+        logical_id = f"{lambda_function.logical_id}URLInvokeAllowPublicAccess"
+        lambda_permission_attributes = self.get_passthrough_resource_attributes()
+        lambda_invoke_permission = LambdaPermission(logical_id=logical_id, attributes=lambda_permission_attributes)
+        lambda_invoke_permission.Action = "lambda:InvokeFunction"
+        lambda_invoke_permission.Principal = "*"
+        lambda_invoke_permission.FunctionName = (
+            lambda_alias.get_runtime_attr("arn") if lambda_alias else lambda_function.get_runtime_attr("name")
+        )
+        lambda_invoke_permission.InvokedViaFunctionUrl = True
+
+        return lambda_invoke_permission
+
 
 class SamApi(SamResourceMacro):
     """SAM rest API macro."""

tests/model/test_sam_resources.py

@@ -583,11 +583,29 @@ def test_with_valid_function_url_config_with_lambda_permission(self):
 
         cfnResources = function.to_cloudformation(**self.kwargs)
         generatedUrlList = [x for x in cfnResources if isinstance(x, LambdaPermission)]
-        self.assertEqual(generatedUrlList.__len__(), 1)
-        self.assertEqual(generatedUrlList[0].Action, "lambda:InvokeFunctionUrl")
-        self.assertEqual(generatedUrlList[0].FunctionName, {"Ref": "foo"})
-        self.assertEqual(generatedUrlList[0].Principal, "*")
-        self.assertEqual(generatedUrlList[0].FunctionUrlAuthType, "NONE")
+        self.assertEqual(generatedUrlList.__len__(), 2)
+        for permission in generatedUrlList:
+            self.assertEqual(permission.FunctionName, {"Ref": "foo"})
+            self.assertEqual(permission.Principal, "*")
+            self.assertTrue(permission.Action in ["lambda:InvokeFunctionUrl", "lambda:InvokeFunction"])
+            if permission.Action == "lambda:InvokeFunctionUrl":
+                self.assertEqual(permission.FunctionUrlAuthType, "NONE")
+            if permission.Action == "lambda:InvokeFunction":
+                self.assertEqual(permission.InvokedViaFunctionUrl, True)
+
+    @patch("boto3.session.Session.region_name", "ap-southeast-1")
+    def test_with_aws_iam_function_url_config_with_lambda_permission(self):
+        function = SamFunction("foo")
+        function.CodeUri = "s3://foobar/foo.zip"
+        function.Runtime = "foo"
+        function.Handler = "bar"
+        # When create FURL with AWS_IAM
+        function.FunctionUrlConfig = {"AuthType": "AWS_IAM"}
+
+        cfnResources = function.to_cloudformation(**self.kwargs)
+        generatedUrlList = [x for x in cfnResources if isinstance(x, LambdaPermission)]
+        # Then no permisssion should be auto created
+        self.assertEqual(generatedUrlList.__len__(), 0)
 
     @patch("boto3.session.Session.region_name", "ap-southeast-1")
     def test_with_invalid_function_url_config_with_authorization_type_value_as_None(self):

tests/translator/output/aws-cn/function_with_function_url_config.json

@@ -58,6 +58,17 @@
       },
       "Type": "AWS::IAM::Role"
     },
+    "MyFunctionURLInvokeAllowPublicAccess": {
+      "Properties": {
+        "Action": "lambda:InvokeFunction",
+        "FunctionName": {
+          "Ref": "MyFunction"
+        },
+        "InvokedViaFunctionUrl": true,
+        "Principal": "*"
+      },
+      "Type": "AWS::Lambda::Permission"
+    },
     "MyFunctionUrl": {
       "Properties": {
         "AuthType": "NONE",