Add rule E3663 to validate lambda fn env vars

src/cfnlint/data/schemas/extensions/aws_lambda_function/environment_variable_keys.json

@@ -0,0 +1,26 @@
+{
+ "propertyNames": {
+  "not": {
+   "enum": [
+    "_HANDLER",
+    "_X_AMZN_TRACE_ID",
+    "AWS_DEFAULT_REGION",
+    "AWS_REGION",
+    "AWS_EXECUTION_ENV",
+    "AWS_LAMBDA_FUNCTION_NAME",
+    "AWS_LAMBDA_FUNCTION_MEMORY_SIZE",
+    "AWS_LAMBDA_FUNCTION_VERSION",
+    "AWS_LAMBDA_INITIALIZATION_TYPE",
+    "AWS_LAMBDA_LOG_GROUP_NAME",
+    "AWS_LAMBDA_LOG_STREAM_NAME",
+    "AWS_ACCESS_KEY",
+    "AWS_ACCESS_KEY_ID",
+    "AWS_SECRET_ACCESS_KEY",
+    "AWS_SESSION_TOKEN",
+    "AWS_LAMBDA_RUNTIME_API",
+    "LAMBDA_TASK_ROOT",
+    "LAMBDA_RUNTIME_DIR"
+   ]
+  }
+ }
+}

src/cfnlint/rules/resources/lmbd/FunctionEnvironmentKeys.py

@@ -0,0 +1,51 @@
+"""
+Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+SPDX-License-Identifier: MIT-0
+"""
+
+from __future__ import annotations
+
+from typing import Any
+
+import cfnlint.data.schemas.extensions.aws_lambda_function
+from cfnlint.jsonschema import ValidationResult
+from cfnlint.jsonschema.protocols import Validator
+from cfnlint.rules.jsonschema import CfnLintJsonSchema, SchemaDetails
+
+
+class FunctionEnvironmentKeys(CfnLintJsonSchema):
+
+    id = "E3663"
+    shortdesc = "Validate Lambda environment variable names aren't reserved"
+    description = (
+        "Lambda reserves a set of environment variable names for its use. "
+        "This rule validates that the provided environment variable names "
+        "don't use the reserved variable names"
+    )
+    source_url = (
+        "https://docs.aws.amazon.com/lambda/latest/dg/configuration-envvars.html"
+    )
+    tags = ["resources", "lambda", "runtime"]
+
+    def __init__(self):
+        """Init"""
+        super().__init__(
+            keywords=[
+                "Resources/AWS::Lambda::Function/Properties/Environment/Variables"
+            ],
+            schema_details=SchemaDetails(
+                cfnlint.data.schemas.extensions.aws_lambda_function,
+                "environment_variable_keys.json",
+            ),
+            all_matches=True,
+        )
+
+    def validate(
+        self, validator: Validator, keywords: Any, instance: Any, schema: dict[str, Any]
+    ) -> ValidationResult:
+        for err in super().validate(validator, keywords, instance, schema):
+            err.message = (
+                f"{err.instance!r} is a reserved variable name, one of "
+                f"{self.schema.get('propertyNames').get('not').get('enum')!r}"
+            )
+            yield err

test/unit/rules/resources/lmbd/test_function_environment_keys.py

@@ -0,0 +1,109 @@
+"""
+Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+SPDX-License-Identifier: MIT-0
+"""
+
+from collections import deque
+
+import pytest
+
+from cfnlint.jsonschema import ValidationError
+from cfnlint.rules.resources.lmbd.FunctionEnvironmentKeys import FunctionEnvironmentKeys
+
+
+@pytest.fixture(scope="module")
+def rule():
+    rule = FunctionEnvironmentKeys()
+    yield rule
+
+
+@pytest.mark.parametrize(
+    "instance,expected",
+    [
+        (
+            {"Foo": "Bar"},
+            [],
+        ),
+        (
+            {"AWS_REGION": "Bar"},
+            [
+                ValidationError(
+                    (
+                        "'AWS_REGION' is a reserved variable name, one of "
+                        "['_HANDLER', '_X_AMZN_TRACE_ID', 'AWS_DEFAULT_REGION', "
+                        "'AWS_REGION', 'AWS_EXECUTION_ENV', "
+                        "'AWS_LAMBDA_FUNCTION_NAME', "
+                        "'AWS_LAMBDA_FUNCTION_MEMORY_SIZE', "
+                        "'AWS_LAMBDA_FUNCTION_VERSION', "
+                        "'AWS_LAMBDA_INITIALIZATION_TYPE', "
+                        "'AWS_LAMBDA_LOG_GROUP_NAME', "
+                        "'AWS_LAMBDA_LOG_STREAM_NAME', "
+                        "'AWS_ACCESS_KEY', 'AWS_ACCESS_KEY_ID', "
+                        "'AWS_SECRET_ACCESS_KEY', "
+                        "'AWS_SESSION_TOKEN', 'AWS_LAMBDA_RUNTIME_API', "
+                        "'LAMBDA_TASK_ROOT', 'LAMBDA_RUNTIME_DIR']"
+                    ),
+                    schema_path=deque(["propertyNames", "not"]),
+                    path=deque(["AWS_REGION"]),
+                    rule=FunctionEnvironmentKeys(),
+                    validator="not",
+                )
+            ],
+        ),
+        (
+            {
+                "Foo": "Bar",
+                "AWS_REGION": "Bar",
+                "Bar": "Foo",
+                "AWS_ACCESS_KEY": "Foo",
+            },
+            [
+                ValidationError(
+                    (
+                        "'AWS_REGION' is a reserved variable name, one of "
+                        "['_HANDLER', '_X_AMZN_TRACE_ID', 'AWS_DEFAULT_REGION', "
+                        "'AWS_REGION', 'AWS_EXECUTION_ENV', "
+                        "'AWS_LAMBDA_FUNCTION_NAME', "
+                        "'AWS_LAMBDA_FUNCTION_MEMORY_SIZE', "
+                        "'AWS_LAMBDA_FUNCTION_VERSION', "
+                        "'AWS_LAMBDA_INITIALIZATION_TYPE', "
+                        "'AWS_LAMBDA_LOG_GROUP_NAME', "
+                        "'AWS_LAMBDA_LOG_STREAM_NAME', "
+                        "'AWS_ACCESS_KEY', 'AWS_ACCESS_KEY_ID', "
+                        "'AWS_SECRET_ACCESS_KEY', "
+                        "'AWS_SESSION_TOKEN', 'AWS_LAMBDA_RUNTIME_API', "
+                        "'LAMBDA_TASK_ROOT', 'LAMBDA_RUNTIME_DIR']"
+                    ),
+                    schema_path=deque(["propertyNames", "not"]),
+                    path=deque(["AWS_REGION"]),
+                    rule=FunctionEnvironmentKeys(),
+                    validator="not",
+                ),
+                ValidationError(
+                    (
+                        "'AWS_ACCESS_KEY' is a reserved variable name, one of "
+                        "['_HANDLER', '_X_AMZN_TRACE_ID', 'AWS_DEFAULT_REGION', "
+                        "'AWS_REGION', 'AWS_EXECUTION_ENV', "
+                        "'AWS_LAMBDA_FUNCTION_NAME', "
+                        "'AWS_LAMBDA_FUNCTION_MEMORY_SIZE', "
+                        "'AWS_LAMBDA_FUNCTION_VERSION', "
+                        "'AWS_LAMBDA_INITIALIZATION_TYPE', "
+                        "'AWS_LAMBDA_LOG_GROUP_NAME', "
+                        "'AWS_LAMBDA_LOG_STREAM_NAME', "
+                        "'AWS_ACCESS_KEY', 'AWS_ACCESS_KEY_ID', "
+                        "'AWS_SECRET_ACCESS_KEY', "
+                        "'AWS_SESSION_TOKEN', 'AWS_LAMBDA_RUNTIME_API', "
+                        "'LAMBDA_TASK_ROOT', 'LAMBDA_RUNTIME_DIR']"
+                    ),
+                    schema_path=deque(["propertyNames", "not"]),
+                    path=deque(["AWS_ACCESS_KEY"]),
+                    rule=FunctionEnvironmentKeys(),
+                    validator="not",
+                ),
+            ],
+        ),
+    ],
+)
+def test_validate(instance, expected, rule, validator):
+    errs = list(rule.validate(validator, "LambdaRuntime", instance, {}))
+    assert errs == expected, f"Expected {expected} got {errs}"