Server Authentication in Swift 2.0 & XCode 7 broken

Question

I just updated my code to Swift 2.0 to work with Xcode 7. My App performs NSURLAuthenticationMethodServerTrust and NSURLAuthenticationMethodClientCertificate authentication.

The problem is NSURLAuthenticationMethodServerTrust authentication stopped working on my simulator - but still works on my test device with iOS 8.3. Besides my old project which is not Swift 2.0, is also still working.

Error: NSURLSession/NSURLConnection HTTP load failed (kCFStreamErrorDomainSSL, -9802)

Error retrieved from NSURLSession:

Error Domain=NSURLErrorDomain Code=-1200 "An SSL error has occurred and a secure connection to the server cannot be made." UserInfo=0x7fcf75053070 {NSURLErrorFailingURLPeerTrustErrorKey=<SecTrustRef: 0x7fcf73700d00>, NSLocalizedRecoverySuggestion=Would you like to connect to the server anyway?, _kCFStreamErrorCodeKey=-9802, NSUnderlyingError=0x7fcf735284b0 "The operation couldn’t be completed. (kCFErrorDomainCFNetwork error -1200.)", NSLocalizedDescription=An SSL error has occurred and a secure connection to the server cannot be made., NSErrorFailingURLKey=https://mywebapi/dosomething, NSErrorFailingURLStringKey=https://mywebapi/dosomething, _kCFStreamErrorDomainKey=3} [GetOneTimeTokenController.swift:76]

I am still targeting iOS 8.0 for deployment.

This is how I handle the Authentication Challenge (using a self signed certificate):

if challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodClientCertificate {

        let urlCredential:NSURLCredential = NSURLCredential(
            identity: identityAndTrust.identityRef,
            certificates: identityAndTrust.certArray as [AnyObject],
            persistence: NSURLCredentialPersistence.ForSession);

        completionHandler(NSURLSessionAuthChallengeDisposition.UseCredential, urlCredential);

    } else if challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust {

        completionHandler(NSURLSessionAuthChallengeDisposition.UseCredential, NSURLCredential(trust: challenge.protectionSpace.serverTrust!));

    } else {

        challenge.sender?.continueWithoutCredentialForAuthenticationChallenge(challenge)
        Logger.sharedInstance.logMessage("Unexpected Authentication Challange", .Error);

    }

Answer 1

Your simulator is most likely running iOS 9 then. In iOS 9, TLS 1.2 is enforced. If you're not using it, your requests will fail.

Check out this post for more info.

You can bypass it by putting this in your Info.plist :

<key>NSAppTransportSecurity</key>
<dict>
  <!--Include to allow all connections (DANGER)-->
  <key>NSAllowsArbitraryLoads</key>
      <true/>
</dict>

but it is simply a temporary workaround until you can implement TLS 1.2.

Answer 2

You don't have bypass the TLS layer. Please find the answer below which worked for me using self signed certificate.

Following are the code changes which works fine with Self Signed SSL certificate

  func URLSession(session: NSURLSession, didReceiveChallenge challenge: NSURLAuthenticationChallenge, completionHandler: (NSURLSessionAuthChallengeDisposition, NSURLCredential?) -> Void) {

    if challenge.protectionSpace.authenticationMethod == (NSURLAuthenticationMethodServerTrust) {


    let serverTrust:SecTrustRef = challenge.protectionSpace.serverTrust!
    let certificate: SecCertificateRef = SecTrustGetCertificateAtIndex(serverTrust, 0)!
    let remoteCertificateData = CFBridgingRetain(SecCertificateCopyData(certificate))!
    let cerPath: String = NSBundle.mainBundle().pathForResource("xyz.com", ofType: "cer")!
    let localCertificateData = NSData(contentsOfFile:cerPath)!


        if (remoteCertificateData.isEqualToData(localCertificateData) == true) {
            let credential:NSURLCredential = NSURLCredential(forTrust: serverTrust)

            challenge.sender?.useCredential(credential, forAuthenticationChallenge: challenge)


            completionHandler(NSURLSessionAuthChallengeDisposition.UseCredential, NSURLCredential(forTrust: challenge.protectionSpace.serverTrust!))

        } else {

            completionHandler(NSURLSessionAuthChallengeDisposition.CancelAuthenticationChallenge, nil)
        }
    }
    else if challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodClientCertificate
    {

        let path: String = NSBundle.mainBundle().pathForResource("client", ofType: "p12")!
        let PKCS12Data = NSData(contentsOfFile:path)!


        let identityAndTrust:IdentityAndTrust = self.extractIdentity(PKCS12Data);



            let urlCredential:NSURLCredential = NSURLCredential(
                identity: identityAndTrust.identityRef,
                certificates: identityAndTrust.certArray as? [AnyObject],
                persistence: NSURLCredentialPersistence.ForSession);

            completionHandler(NSURLSessionAuthChallengeDisposition.UseCredential, urlCredential);




    }
    else
    {
        completionHandler(NSURLSessionAuthChallengeDisposition.CancelAuthenticationChallenge, nil);
    }
}

 struct IdentityAndTrust {

    var identityRef:SecIdentityRef
    var trust:SecTrustRef
    var certArray:AnyObject
}

func extractIdentity(certData:NSData) -> IdentityAndTrust {
    var identityAndTrust:IdentityAndTrust!
    var securityError:OSStatus = errSecSuccess

    let path: String = NSBundle.mainBundle().pathForResource("client", ofType: "p12")!
    let PKCS12Data = NSData(contentsOfFile:path)!
    let key : NSString = kSecImportExportPassphrase as NSString
    let options : NSDictionary = [key : "xyz"]
    //create variable for holding security information
    //var privateKeyRef: SecKeyRef? = nil

    var items : CFArray?

     securityError = SecPKCS12Import(PKCS12Data, options, &items)

    if securityError == errSecSuccess {
        let certItems:CFArray = items as CFArray!;
        let certItemsArray:Array = certItems as Array
        let dict:AnyObject? = certItemsArray.first;
        if let certEntry:Dictionary = dict as? Dictionary<String, AnyObject> {

            // grab the identity
            let identityPointer:AnyObject? = certEntry["identity"];
            let secIdentityRef:SecIdentityRef = identityPointer as! SecIdentityRef!;
            print("\(identityPointer)  :::: \(secIdentityRef)")
            // grab the trust
            let trustPointer:AnyObject? = certEntry["trust"];
            let trustRef:SecTrustRef = trustPointer as! SecTrustRef;
            print("\(trustPointer)  :::: \(trustRef)")
            // grab the cert
            let chainPointer:AnyObject? = certEntry["chain"];
            identityAndTrust = IdentityAndTrust(identityRef: secIdentityRef, trust: trustRef, certArray:  chainPointer!);
        }
    }
    return identityAndTrust;
}

Changes done in the info.plist file

     <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>NSExceptionDomains</key>
    <dict>
        <key>amazonaws.com.cn</key>
        <dict>
            <key>NSIncludesSubdomains</key>
            <true/>
            <key>NSThirdPartyExceptionRequiresForwardSecrecy</key>
            <false/>
            <key>NSThirdPartyExceptionMinimumTLSVersion</key>
            <string>TLSv1.0</string>
        </dict>
        <key>amazonaws.com</key>
        <dict>
            <key>NSIncludesSubdomains</key>
            <true/>
            <key>NSThirdPartyExceptionRequiresForwardSecrecy</key>
            <false/>
            <key>NSThirdPartyExceptionMinimumTLSVersion</key>
            <string>TLSv1.0</string>
        </dict>
        <key>xyz.com</key>
        <dict>
            <key>NSExceptionAllowsInsecureHTTPLoads</key>
            <true/>
            <key>NSTemporaryExceptionMinimumTLSVersion</key>
            <string>TLSv1.2</string>
            <key>NSRequiresCertificateTransparency</key>
            <false/>
            <key>NSIncludesSubdomains</key>
            <true/>
        </dict>
    </dict>
    <key>NSAllowsArbitraryLoads</key>
    <false/>
</dict>
</plist>

Answer 3

I had same problem with iOS9 & xcode 7 Just add :

<key>NSAppTransportSecurity</key> 
<dict> 
    <key>NSAllowsArbitraryLoads</key> 
    <true/> 
</dict> 

to the plist file . It is working but it is a temporary workaround until you can implement TLS 1.2.