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226 changes: 16 additions & 210 deletions
226
...er/composite-resources/serverless-examples/microservice/src/authorizer/lambda_function.py
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# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. | ||
# SPDX-License-Identifier: MIT-0 | ||
# SPDX-License-Identifier: Apache-2.0 | ||
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# IMPORTANT: | ||
# This is sample implementation of a Lambda Authorizer | ||
# It generates IAM policy that allows ALL actions on your API to be performed by ANYONE | ||
# This is sample implementation of a Lambda Authorizer, it generates IAM policy that allows ALL actions on your API to be performed by ANYONE | ||
# Make sure to update code below to limit access to the resources based on your use case | ||
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import json | ||
import re | ||
# For more details on how to implement Lambda Authorizer, check out documentation at https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-use-lambda-authorizer.html | ||
# You may also use the Lambda Authorizer blueprints at https://github.com/awslabs/aws-apigateway-lambda-authorizer-blueprints | ||
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def lambda_handler(event, context): | ||
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# print("Client token: " + event['authorizationToken']) | ||
print("Event: " + json.dumps(event)) | ||
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''' | ||
Validate the incoming token and produce the principal user identifier | ||
associated with the token. This can be accomplished in a number of ways: | ||
1. Call out to the OAuth provider | ||
2. Decode a JWT token inline | ||
3. Lookup in a self-managed DB | ||
''' | ||
principalId = 'TestUser' #event['authorizationToken'] | ||
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''' | ||
You can send a 401 Unauthorized response to the client by failing like so: | ||
raise Exception('Unauthorized') | ||
If the token is valid, a policy must be generated which will allow or deny | ||
access to the client. If access is denied, the client will receive a 403 | ||
Access Denied response. If access is allowed, API Gateway will proceed with | ||
the backend integration configured on the method that was called. | ||
This function must generate a policy that is associated with the recognized | ||
principal user identifier. Depending on your use case, you might store | ||
policies in a DB, or generate them on the fly. | ||
Keep in mind, the policy is cached for 5 minutes by default (TTL is | ||
configurable in the authorizer) and will apply to subsequent calls to any | ||
method/resource in the RestApi made with the same token. | ||
The example policy below denies access to all resources in the RestApi. | ||
''' | ||
tmp = event['methodArn'].split(':') | ||
apiGatewayArnTmp = tmp[5].split('/') | ||
awsAccountId = tmp[4] | ||
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policy = AuthPolicy(principalId, '*') | ||
policy.restApiId = '*' | ||
policy.region = '*' | ||
policy.stage = '*' | ||
# policy.denyAllMethods() | ||
policy.allowMethod(HttpVerb.ALL, '/*') | ||
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# Finally, build the policy | ||
authResponse = policy.build() | ||
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print(authResponse) | ||
authResponse = { | ||
"principalId": "TestUser", | ||
"policyDocument": { | ||
"Version": "2012-10-17", | ||
"Statement": [ | ||
{ | ||
"Action": "execute-api:Invoke", | ||
"Effect": "Allow", | ||
"Resource": [ | ||
"arn:aws:execute-api:*:*:*/*/*/*" | ||
] | ||
}]}} | ||
return authResponse | ||
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class HttpVerb: | ||
GET = 'GET' | ||
POST = 'POST' | ||
PUT = 'PUT' | ||
PATCH = 'PATCH' | ||
HEAD = 'HEAD' | ||
DELETE = 'DELETE' | ||
OPTIONS = 'OPTIONS' | ||
ALL = '*' | ||
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class AuthPolicy(object): | ||
# The AWS account id the policy will be generated for. This is used to create the method ARNs. | ||
awsAccountId = '' | ||
# The principal used for the policy, this should be a unique identifier for the end user. | ||
principalId = '' | ||
# The policy version used for the evaluation. This should always be '2012-10-17' | ||
version = '2012-10-17' | ||
# The regular expression used to validate resource paths for the policy | ||
pathRegex = '^[/.a-zA-Z0-9-\*]+$' | ||
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'''Internal lists of allowed and denied methods. | ||
These are lists of objects and each object has 2 properties: A resource | ||
ARN and a nullable conditions statement. The build method processes these | ||
lists and generates the approriate statements for the final policy. | ||
''' | ||
allowMethods = [] | ||
denyMethods = [] | ||
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# The API Gateway API id. By default this is set to '*' | ||
restApiId = '*' | ||
# The region where the API is deployed. By default this is set to '*' | ||
region = '*' | ||
# The name of the stage used in the policy. By default this is set to '*' | ||
stage = '*' | ||
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def __init__(self, principal, awsAccountId): | ||
self.awsAccountId = awsAccountId | ||
self.principalId = principal | ||
self.allowMethods = [] | ||
self.denyMethods = [] | ||
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def _addMethod(self, effect, verb, resource, conditions): | ||
'''Adds a method to the internal lists of allowed or denied methods. Each object in | ||
the internal list contains a resource ARN and a condition statement. The condition | ||
statement can be null.''' | ||
if verb != '*' and not hasattr(HttpVerb, verb): | ||
raise NameError('Invalid HTTP verb ' + verb + '. Allowed verbs in HttpVerb class') | ||
resourcePattern = re.compile(self.pathRegex) | ||
if not resourcePattern.match(resource): | ||
raise NameError('Invalid resource path: ' + resource + '. Path should match ' + self.pathRegex) | ||
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if resource[:1] == '/': | ||
resource = resource[1:] | ||
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resourceArn = 'arn:aws:execute-api:{}:{}:{}/{}/{}/{}'.format(self.region, self.awsAccountId, self.restApiId, self.stage, verb, resource) | ||
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if effect.lower() == 'allow': | ||
self.allowMethods.append({ | ||
'resourceArn': resourceArn, | ||
'conditions': conditions | ||
}) | ||
elif effect.lower() == 'deny': | ||
self.denyMethods.append({ | ||
'resourceArn': resourceArn, | ||
'conditions': conditions | ||
}) | ||
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def _getEmptyStatement(self, effect): | ||
'''Returns an empty statement object prepopulated with the correct action and the | ||
desired effect.''' | ||
statement = { | ||
'Action': 'execute-api:Invoke', | ||
'Effect': effect[:1].upper() + effect[1:].lower(), | ||
'Resource': [] | ||
} | ||
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return statement | ||
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def _getStatementForEffect(self, effect, methods): | ||
'''This function loops over an array of objects containing a resourceArn and | ||
conditions statement and generates the array of statements for the policy.''' | ||
statements = [] | ||
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if len(methods) > 0: | ||
statement = self._getEmptyStatement(effect) | ||
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for curMethod in methods: | ||
if curMethod['conditions'] is None or len(curMethod['conditions']) == 0: | ||
statement['Resource'].append(curMethod['resourceArn']) | ||
else: | ||
conditionalStatement = self._getEmptyStatement(effect) | ||
conditionalStatement['Resource'].append(curMethod['resourceArn']) | ||
conditionalStatement['Condition'] = curMethod['conditions'] | ||
statements.append(conditionalStatement) | ||
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if statement['Resource']: | ||
statements.append(statement) | ||
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return statements | ||
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def allowAllMethods(self): | ||
'''Adds a '*' allow to the policy to authorize access to all methods of an API''' | ||
self._addMethod('Allow', HttpVerb.ALL, '*', []) | ||
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def denyAllMethods(self): | ||
'''Adds a '*' allow to the policy to deny access to all methods of an API''' | ||
self._addMethod('Deny', HttpVerb.ALL, '*', []) | ||
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def allowMethod(self, verb, resource): | ||
'''Adds an API Gateway method (Http verb + Resource path) to the list of allowed | ||
methods for the policy''' | ||
self._addMethod('Allow', verb, resource, []) | ||
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def denyMethod(self, verb, resource): | ||
'''Adds an API Gateway method (Http verb + Resource path) to the list of denied | ||
methods for the policy''' | ||
self._addMethod('Deny', verb, resource, []) | ||
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def allowMethodWithConditions(self, verb, resource, conditions): | ||
'''Adds an API Gateway method (Http verb + Resource path) to the list of allowed | ||
methods and includes a condition for the policy statement. More on AWS policy | ||
conditions here: http://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements.html#Condition''' | ||
self._addMethod('Allow', verb, resource, conditions) | ||
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def denyMethodWithConditions(self, verb, resource, conditions): | ||
'''Adds an API Gateway method (Http verb + Resource path) to the list of denied | ||
methods and includes a condition for the policy statement. More on AWS policy | ||
conditions here: http://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements.html#Condition''' | ||
self._addMethod('Deny', verb, resource, conditions) | ||
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def build(self): | ||
'''Generates the policy document based on the internal lists of allowed and denied | ||
conditions. This will generate a policy with two main statements for the effect: | ||
one statement for Allow and one statement for Deny. | ||
Methods that includes conditions will have their own statement in the policy.''' | ||
if ((self.allowMethods is None or len(self.allowMethods) == 0) and | ||
(self.denyMethods is None or len(self.denyMethods) == 0)): | ||
raise NameError('No statements defined for the policy') | ||
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policy = { | ||
'principalId': self.principalId, | ||
'policyDocument': { | ||
'Version': self.version, | ||
'Statement': [] | ||
} | ||
} | ||
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policy['policyDocument']['Statement'].extend(self._getStatementForEffect('Allow', self.allowMethods)) | ||
policy['policyDocument']['Statement'].extend(self._getStatementForEffect('Deny', self.denyMethods)) | ||
policy["usageIdentifierKey"]="12345678901234567890" | ||
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return policy |
2 changes: 1 addition & 1 deletion
2
...rovider/composite-resources/serverless-examples/microservice/src/logic/lambda_function.py
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