title: "Principal" attribute in "AWS::SQS::QueuePolicy" is not taking in AWS ARN
body: <p>I have created SNS and SQS with CloudFormantion in different accounts and was able to subscribe to SNS, able to receive messages, working as expected. Code used:</p>
  <p>CF in Account-02:</p>
  <pre><code>AWSTemplateFormatVersion: 2010-09-09
      Resources:
          Queue:
          Type: AWS::SQS::Queue
          Properties:
              QueueName: &quot;SampleQueue&quot;
          SqsQueuePolicy:
          Type: AWS::SQS::QueuePolicy
          Properties:
              PolicyDocument:
              Version: '2012-10-17'
              Id: MyQueuePolicy
              Statement:
                  - Sid: Allow-SNS-SendMessage
                  Effect: Allow
                  Principal: &quot;*&quot;
                  Action:
                      - sqs:SendMessage
                  Resource: !GetAtt Queue.Arn
                  Condition:
                      ArnEquals:
                      aws:SourceArn: &quot;arn:aws:sns:eu-west-1:&lt;account-01&gt;:SampleTopic&quot;
              Queues:
              - !Ref Queue
      
          SnsSubscription:
          Type: AWS::SNS::Subscription
          Properties:
              Protocol: sqs
              Endpoint: !GetAtt Queue.Arn
              Region: &quot;eu-west-1&quot;
  
              TopicArn: &quot;arn:aws:sns:eu-west-1:&lt;account-01&gt;:SampleTopic&quot;
  </code></pre>
  <p>When Principal is set as below, it doesn't work(no messages are received to SQS). Anything wrong in it?</p>
  <pre><code>Principal:
      AWS:
        - arn:aws:iam::&lt;account-02&gt;:user/user01
  </code></pre>
  <p>It also works expected with &quot;SQS::QueuePolicy&quot; Principal as below:</p>
  <pre><code>Principal:
      Service:
        - sns.amazonaws.com
  </code></pre>
  <p>Want to check why Principal is not taking a valid AWS ARN?</p>
  <p>(yes, the Condition element in the Policy is restrictive enough, other topics cannot post to the queue, but our security team is not happy with this...want to understand why Principal is not taking in a valid one? )</p>