Use CalledVia context keys for Athena

When a principal makes a request to AWS, AWS gathers the request information into a request context that evaluates and authorizes the request. You can use the Condition element of a JSON policy to compare keys in the request context with key values that you specify in your policy. Global condition context keys are condition keys with an aws: prefix.

About the aws:CalledVia context key

You can use the aws:CalledVia global condition context key to compare the services in the policy with the services that made requests on behalf of the IAM principal (user or role). When a principal makes a request to an AWS service, that service might use the principal's credentials to make subsequent requests to other services. The aws:CalledVia key contains an ordered list of each service in the chain that made requests on the principal's behalf.

By specifying a service principal name for the aws:CalledVia context key, you can make the context key AWS service-specific. For example, you can use the aws:CalledVia condition key to limit requests to only those made from Athena. To use the aws:CalledVia condition key in a policy with Athena, you specify the Athena service principal name athena.amazonaws.com, as in the following example.

 ...
    "Condition": {
        "ForAnyValue:StringEquals": { 
            "aws:CalledVia": "athena.amazonaws.com"
        }
    }
...

You can use the aws:CalledVia context key to ensure that callers only have access to a resource (like a Lambda function) if they call the resource from Athena.

Add a CalledVia context key for access to Lambda functions

Athena requires the caller to have lambda:InvokeFunction permissions in order to invoke the Lambda function associated with the query. The following statement specifies that the user can invoke Lambda functions only from Athena.

JSON

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "VisualEditor3",
            "Effect": "Allow",
            "Action": "lambda:InvokeFunction",
            "Resource": "arn:aws:lambda:us-east-1:111122223333:function:OneAthenaLambdaFunction",
            "Condition": {
                "ForAnyValue:StringEquals": {
                    "aws:CalledVia": "athena.amazonaws.com"
                }
            }
        }
    ]
}

The following example shows the addition of the previous statement to a policy that allows a user to run and read a federated query. Principals who are allowed to perform these actions can run queries that specify Athena catalogs associated with a federated data source. However, the principal cannot access the associated Lambda function unless the function is invoked through Athena.

JSON

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "VisualEditor0", 
            "Effect": "Allow",
            "Action": [ 
                "athena:GetWorkGroup", 
                "s3:PutObject", 
                "s3:GetObject", 
                "athena:StartQueryExecution", 
                "s3:AbortMultipartUpload",  
                "athena:StopQueryExecution", 
                "athena:GetQueryExecution", 
                "athena:GetQueryResults", 
                "s3:ListMultipartUploadParts" 
            ], 
            "Resource": [ 
                "arn:aws:athena:*:111122223333:workgroup/WorkGroupName",
                "arn:aws:s3:::MyQueryResultsBucket/*", 
                "arn:aws:s3:::MyLambdaSpillBucket/MyLambdaSpillPrefix*"
            ] 
        }, 
        {
            "Sid": "VisualEditor1", 
            "Effect": "Allow", 
            "Action": "athena:ListWorkGroups", 
            "Resource": "*" 
        }, 
        {
            "Sid": "VisualEditor2", 
            "Effect": "Allow", 
            "Action": 
                [ 
                "s3:ListBucket", 
                "s3:GetBucketLocation" 
                ], 
            "Resource": "arn:aws:s3:::MyLambdaSpillBucket" 
        },
        {
            "Sid": "VisualEditor3",
            "Effect": "Allow",
            "Action": "lambda:InvokeFunction",
            "Resource": [
                "arn:aws:lambda:*:111122223333:function:OneAthenaLambdaFunction", 
                "arn:aws:lambda:*:111122223333:function:AnotherAthenaLambdaFunction"
            ], 
            "Condition": {
                "ForAnyValue:StringEquals": { 
                    "aws:CalledVia": "athena.amazonaws.com"
                }
            }
        }            
    ]
}

For more information about CalledVia condition keys, see AWS global condition context keys in the IAM User Guide.