AWS: How to properly authenticate a user against Cognito Pool and use it for Cognito Federated Identity?

Question

I am working on an app which will use two authentication providers:

• Facebook
• Cognito User Pool

With the former, I have no issues, everything works as intended. However, while setting up the authentication with Cognito User Pools, I am hitting one wall after the other. I am using AWS SDK 2.4.9, XCode 8 and Swift 3.

I am aware that there are a lot of questions have already been asked, and a lot of "guides" are out there. However, a lot of them are answered/made for outdated docs and SDK. Even the official AWS documentation is out of date.

The authentication steps that I am going through are as follows:

1. Configure the initial cognito pool

///  Set the default service configuration
let serviceConfiguration = AWSServiceConfiguration(region: AWSRegionType.usEast1, credentialsProvider: nil)
AWSServiceManager.default().defaultServiceConfiguration = serviceConfiguration

/// Create a pool configuration and register it for a specific key to use later
let poolConfiguration = AWSCognitoIdentityUserPoolConfiguration(clientId: appClientID, clientSecret: appClientSecret, poolId: poolID)  
AWSCognitoIdentityUserPool.registerCognitoIdentityUserPool(with: poolConfiguration, forKey: poolKey)

/// Create a pool for a specific predefined key
pool = AWSCognitoIdentityUserPool(forKey: poolKey)

2. Authenticate the user against Cognito User Pool

  user.getSession(username, password: password, validationData: nil).continue({ (task) -> AnyObject? in

        if let error = task.error as? NSError {
            completionHandler(error)
            return nil
        }

        let session = task.result! as AWSCognitoIdentityUserSession
        let token = session.idToken!.tokenString

        let tokens : [NSString:NSString] = ["cognito-idp.us-east-1.amazonaws.com/\(self.poolID!)" as NSString : token as NSString]
        let identityProvider = CognitoPoolIdentityProvider(tokens: tokens)

        let credentialsProvider = AWSCognitoCredentialsProvider(regionType: .usEast1, identityPoolId: self.identityPoolID, identityProviderManager: identityProvider)

        ///  Set the default service configuration
        let serviceConfiguration = AWSServiceConfiguration(region: AWSRegionType.usEast1, credentialsProvider: credentialsProvider)
        AWSServiceManager.default().defaultServiceConfiguration = serviceConfiguration

        credentialsProvider.getIdentityId().continue({ (task) -> AnyObject? in
            completionHandler(task.error as NSError?)
            return nil
        })

        return nil
    })

3. The CognitoPoolIdentityProvider class

    class CognitoPoolIdentityProvider : NSObject, AWSIdentityProviderManager {

      var tokens : NSDictionary = [:]

      init(tokens: [NSString : NSString]) {
           self.tokens = tokens as NSDictionary
      }

      @objc func logins() -> AWSTask<NSDictionary> {
           return AWSTask(result: tokens)
      }

    }

4. Storing data to Cognito Federated Identity

All this passes without any errors. However, now I want to store the data that I have pulled from Cognito Pool to a specific Cognito Federated Identity Dataset, so I am calling: userProfile.synchronize().continue and I am getting the following results:

getCredentialsWithCognito:authenticated:customRoleArn:]_block_invoke | GetCredentialsForIdentity failed. Error is [Error Domain=com.amazonaws.AWSCognitoIdentityErrorDomain Code=8 "(null)" UserInfo={__type=NotAuthorizedException, message=Access to Identity 'us-east-1:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx' is forbidden.}]

2016-11-10 10:27:16.947365 xxxxxxxx[19867:5614838] AWSiOSSDK v2.4.11 [Error] AWSIdentityProvider.m line:304 | __52-[AWSCognitoCredentialsProviderHelper getIdentityId]_block_invoke.255 | GetId failed. Error is [Error Domain=com.amazonaws.AWSCognitoIdentityErrorDomain Code=8 "(null)" UserInfo={__type=NotAuthorizedException, message=Unauthenticated access is not supported for this identity pool.}] 2016-11-10 10:27:16.947726 xxxxxxxx[19867:5614838] AWSiOSSDK v2.4.11 [Error]

AWSCredentialsProvider.m line:577 | __44-[AWSCognitoCredentialsProvider credentials]_block_invoke.352 | Unable to refresh. Error is [Error Domain=com.amazonaws.AWSCognitoIdentityErrorDomain Code=8 "(null)" UserInfo={__type=NotAuthorizedException, message=Unauthenticated access is not supported for this identity pool.}] 2016-11-10 10:27:16.948452 xxxxxxxx[19867:5614838] AWSiOSSDK v2.4.11 [Error]

AWSCognitoDataset.m line:352 | __30-[AWSCognitoDataset syncPull:]_block_invoke | Unable to list records: Error Domain=com.amazonaws.AWSCognitoIdentityErrorDomain Code=8 "(null)" UserInfo={__type=NotAuthorizedException, message=Unauthenticated access is not supported for this identity pool.} [10:27:16]: saveSettings AWS task error: The operation couldn’t be completed. (com.amazonaws.AWSCognitoIdentityErrorDomain error 8.)

After changing the log level, I can see the following:

//REQUEST

2016-11-10 10:33:08.095735 xxxxxxxx[19874:5616142] AWSiOSSDK v2.4.11 [Debug] AWSURLSessionManager.m line:543 | -[AWSURLSessionManager printHTTPHeadersAndBodyForRequest:] | Request body: {"IdentityId":"us-east-1:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxx"}

//RESPONSE

2016-11-10 10:33:08.714268 xxxxxxxx[19874:5616154] AWSiOSSDK v2.4.11 [Debug] AWSURLSessionManager.m line:553 | -[AWSURLSessionManager printHTTPHeadersForResponse:] | Response headers: { Connection = "keep-alive"; "Content-Length" = 129; "Content-Type" = "application/x-amz-json-1.1"; Date = "Thu, 10 Nov 2016 09:33:08 GMT"; "x-amzn-ErrorMessage" = "Access to Identity 'us-east-1:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxx' is forbidden."; "x-amzn-ErrorType" = "NotAuthorizedException:"; "x-amzn-RequestId" = "b0ac6fb0-a728-11e6-8413-1fdb846185bb"; }

The above request is the GetID API call. Clearly, it does not match the request format from the AWS Docs: http://docs.aws.amazon.com/cognitoidentity/latest/APIReference/API_GetId.html.

According to the AWSServiceManager class we have this:

/**
 The default service configuration object. This property can be set only once, and any subsequent setters are ignored.
 */
@property (nonatomic, copy) AWSServiceConfiguration *defaultServiceConfiguration;

This means that setting the new service configuration is pointless, but I see no other way to refresh the credentials that I have obtained through the Cognito User Pool authentication.

That's pretty much it. Any ideas?

Thanks

Answer 1

It seems from the error you are getting

  Access to Identity 'us-east-1:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx' is forbidden

that the credentials that you obtained in the first part cannot access the identity you have made the synchronize call with so your identity probably changed.