SSL connection for iOS in Swift

Question

I am trying to install a simple socket (NO HTTP) from my iOS application to my server server (Node.js). The server certificate was created and signed using a custom certificate authority that I made myself. I believe that in order for iOS to trust my server, I will have to somehow add this user CA certificate to the list of trusted certificates that are used to determine the type of trust how TrustStore works in Java / Android.

I tried to connect using the code below and there are no errors, however the write () function does not seem to be successful.

Main view controller:

override func viewDidLoad() { super.viewDidLoad() // Do any additional setup after loading the view, typically from a nib. let api: APIClient = APIClient() api.initialiseSSL("10.13.37.200", port: 8080) api.write("Hello") api.deinitialise() print("Done") } 

Class apiclient

 class APIClient: NSObject, NSStreamDelegate { var readStream: Unmanaged<CFReadStreamRef>? var writeStream: Unmanaged<CFWriteStreamRef>? var inputStream: NSInputStream? var outputStream: NSOutputStream? func initialiseSSL(host: String, port: UInt32) { CFStreamCreatePairWithSocketToHost(kCFAllocatorDefault, host, port, &readStream, &writeStream) inputStream = readStream!.takeRetainedValue() outputStream = writeStream!.takeRetainedValue() inputStream?.delegate = self outputStream?.delegate = self inputStream!.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode) outputStream!.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode) let cert: SecCertificateRef? = CreateCertificateFromFile("ca", ext: "der") if cert != nil { print("GOT CERTIFICATE") } let certs: NSArray = NSArray(objects: cert!) let sslSettings = [ NSString(format: kCFStreamSSLLevel): kCFStreamSocketSecurityLevelNegotiatedSSL, NSString(format: kCFStreamSSLValidatesCertificateChain): kCFBooleanFalse, NSString(format: kCFStreamSSLPeerName): kCFNull, NSString(format: kCFStreamSSLCertificates): certs, NSString(format: kCFStreamSSLIsServer): kCFBooleanFalse ] CFReadStreamSetProperty(inputStream, kCFStreamPropertySSLSettings, sslSettings) CFWriteStreamSetProperty(outputStream, kCFStreamPropertySSLSettings, sslSettings) inputStream!.open() outputStream!.open() } func write(text: String) { let data = [UInt8](text.utf8) outputStream?.write(data, maxLength: data.count) } func CreateCertificateFromFile(filename: String, ext: String) -> SecCertificateRef? { var cert: SecCertificateRef! if let path = NSBundle.mainBundle().pathForResource(filename, ofType: ext) { let data = NSData(contentsOfFile: path)! cert = SecCertificateCreateWithData(kCFAllocatorDefault, data)! } else { } return cert } func deinitialise() { inputStream?.close() outputStream?.close() } 

}

I understand how SSL / TLS works and that’s all, since I did all this in the Android version of the same application. I am just confused about implementing iOS for SSL.

I am in the background of Java and have been dealing with this problem for 3 weeks. Any help would be appreciated.

Prefer the answers in Swift code rather than Objective-C, but if you have Obj C, that's fine too :)

Answer 1

Well, I spent 8 weeks on this problem :( but I finally managed to put together a working solution. I must say that SSL / TLS on iOS is a joke. Java on Android leaves it dead. To appreciate the trust in a self-signed certificate, you should fully disable certificate chain checking and do it yourself. Absolutely ridiculous. In any case, this is a fully working solution that connects to a remote socket server (without HTTP) using a self-signed server certificate. Feel free to edit this answer. to get a better answer, since I had no changes to add code to send and receive data :)

 // SecureSocket // // Created by snapper26 on 2/9/16. // Copyright © 2016 snapper26. All rights reserved. // import Foundation class ProXimityAPIClient: NSObject, StreamDelegate { // Input and output streams for socket var inputStream: InputStream? var outputStream: OutputStream? // Secondary delegate reference to prevent ARC deallocating the NSStreamDelegate var inputDelegate: StreamDelegate? var outputDelegate: StreamDelegate? // Add a trusted root CA to out SecTrust object func addAnchorToTrust(trust: SecTrust, certificate: SecCertificate) -> SecTrust { let array: NSMutableArray = NSMutableArray() array.add(certificate) SecTrustSetAnchorCertificates(trust, array) return trust } // Create a SecCertificate object from a DER formatted certificate file func createCertificateFromFile(filename: String, ext: String) -> SecCertificate { let rootCertPath = Bundle.main.path(forResource:filename, ofType: ext) let rootCertData = NSData(contentsOfFile: rootCertPath!) return SecCertificateCreateWithData(kCFAllocatorDefault, rootCertData!)! } // Connect to remote host/server func connect(host: String, port: Int) { // Specify host and port number. Get reference to newly created socket streams both in and out Stream.getStreamsToHost(withName:host, port: port, inputStream: &inputStream, outputStream: &outputStream) // Create strong delegate reference to stop ARC deallocating the object inputDelegate = self outputDelegate = self // Now that we have a strong reference, assign the object to the stream delegates inputStream!.delegate = inputDelegate outputStream!.delegate = outputDelegate // This doesn't work because of arc memory management. Thats why another strong reference above is needed. //inputStream!.delegate = self //outputStream!.delegate = self // Schedule our run loops. This is needed so that we can receive StreamEvents inputStream!.schedule(in:RunLoop.main, forMode: RunLoopMode.defaultRunLoopMode) outputStream!.schedule(in:RunLoop.main, forMode: RunLoopMode.defaultRunLoopMode) // Enable SSL/TLS on the streams inputStream!.setProperty(kCFStreamSocketSecurityLevelNegotiatedSSL, forKey: Stream.PropertyKey.socketSecurityLevelKey) outputStream!.setProperty(kCFStreamSocketSecurityLevelNegotiatedSSL, forKey: Stream.PropertyKey.socketSecurityLevelKey) // Defin custom SSL/TLS settings let sslSettings : [NSString: Any] = [ // NSStream automatically sets up the socket, the streams and creates a trust object and evaulates it before you even get a chance to check the trust yourself. Only proper SSL certificates will work with this method. If you have a self signed certificate like I do, you need to disable the trust check here and evaulate the trust against your custom root CA yourself. NSString(format: kCFStreamSSLValidatesCertificateChain): kCFBooleanFalse, // NSString(format: kCFStreamSSLPeerName): kCFNull, // We are an SSL/TLS client, not a server NSString(format: kCFStreamSSLIsServer): kCFBooleanFalse ] // Set the SSL/TLS settingson the streams inputStream!.setProperty(sslSettings, forKey: kCFStreamPropertySSLSettings as Stream.PropertyKey) outputStream!.setProperty(sslSettings, forKey: kCFStreamPropertySSLSettings as Stream.PropertyKey) // Open the streams inputStream!.open() outputStream!.open() } // This is where we get all our events (haven't finished writing this class) func stream(_ aStream: Stream, handle eventCode: Stream.Event) { switch eventCode { case Stream.Event.endEncountered: print("End Encountered") break case Stream.Event.openCompleted: print("Open Completed") break case Stream.Event.hasSpaceAvailable: print("Has Space Available") // If you try and obtain the trust object (aka kCFStreamPropertySSLPeerTrust) before the stream is available for writing I found that the oject is always nil! var sslTrustInput: SecTrust? = inputStream! .property(forKey:kCFStreamPropertySSLPeerTrust as Stream.PropertyKey) as! SecTrust? var sslTrustOutput: SecTrust? = outputStream!.property(forKey:kCFStreamPropertySSLPeerTrust as Stream.PropertyKey) as! SecTrust? if (sslTrustInput == nil) { print("INPUT TRUST NIL") } else { print("INPUT TRUST NOT NIL") } if (sslTrustOutput == nil) { print("OUTPUT TRUST NIL") } else { print("OUTPUT TRUST NOT NIL") } // Get our certificate reference. Make sure to add your root certificate file into your project. let rootCert: SecCertificate? = createCertificateFromFile(filename: "ca", ext: "der") // TODO: Don't want to keep adding the certificate every time??? // Make sure to add your trusted root CA to the list of trusted anchors otherwise trust evaulation will fail sslTrustInput = addAnchorToTrust(trust: sslTrustInput!, certificate: rootCert!) sslTrustOutput = addAnchorToTrust(trust: sslTrustOutput!, certificate: rootCert!) // convert kSecTrustResultUnspecified type to SecTrustResultType for comparison var result: SecTrustResultType = SecTrustResultType.unspecified // This is it! Evaulate the trust. let error: OSStatus = SecTrustEvaluate(sslTrustInput!, &result) // An error occured evaluating the trust check the OSStatus codes for Apple at osstatus.com if (error != noErr) { print("Evaluation Failed") } if (result != SecTrustResultType.proceed && result != SecTrustResultType.unspecified) { // Trust failed. This will happen if you faile to add the trusted anchor as mentioned above print("Peer is not trusted :(") } else { // Peer certificate is trusted. Now we can send data. Woohoo! print("Peer is trusted :)") } break case Stream.Event.hasBytesAvailable: print("Has Bytes Available") break case Stream.Event.errorOccurred: print("Error Occured") break default: print("Default") break } } }