IOS Mutual Authentication

Question

I'm trying to implement mutual authentication in IOS 5 but i'm having troubles:

{NSUnderlyingError = "Error Domain=kCFErrorDomainCFNetwork Code=-1200 \"An SSL error has occurred and a secure connection to the server cannot be made.\" UserInfo=0x18d830 {NSLocalizedDescription=An SSL error has occurred and a secure connection to the server cannot be made., _kCFNetworkCFStreamSSLErrorOriginalValue=-9800, _kCFStreamPropertySSLClientCertificateState=0, NSLocalizedRecoverySuggestion=Would you like to connect to the server anyway?, NSErrorFailingURLStringKey=https://192.168.24.110:8081/t01.json, kCFStreamPropertySSLPeerTrust=<SecTrustRef: 0xceaa2d0>, NSErrorFailingURLKey=https://192.168.24.110:8081/t01.json}

I generated keys, certificates and pkcs12 for server (either self signed or with a fake CA I always got that problem) and client this way:

openssl genrsa -out client.key 1024
openssl req -new -key client.key -out client.csr

self-signed
openssl req -new -key ca.key -x509 -days 1095 -out ca.crt

CA signed
openssl x509 -req -days 365 -in client.csr -CA server.crt -CAkey server.key -CAcreateserial -out client.crt

CRT to PEM
openssl x509 -in client.crt -out client.der -outform DER
openssl x509 -in client.der -inform DER -out client.pem -outform PEM

PEM TO PKCS 12
openssl pkcs12 -export -in client.pem -inkey client.key -out client.p12

The resulting client.p12 file works perfectly when I import it in the browser (FF15). So the problem is not locate in the previous steps.

IOS side I tried this example: http://vanjakom.wordpress.com/tag/nsurlconnection/

and this is what I wrote when I found that example not working:

// Returns an array containing the certificate
- (CFArrayRef)getCertificate:(SecIdentityRef) identity {
    SecCertificateRef certificate = nil;

    SecIdentityCopyCertificate(identity, &certificate);
    SecCertificateRef certs[1] = { certificate };

    CFArrayRef array = CFArrayCreate(NULL, (const void **) certs, 1, NULL);

    SecPolicyRef myPolicy   = SecPolicyCreateBasicX509();
    SecTrustRef myTrust;

    OSStatus status = SecTrustCreateWithCertificates(array, myPolicy, &myTrust);
    if (status == noErr) {
        NSLog(@"No Err creating certificate");
    } else {
        NSLog(@"Possible Err Creating certificate");
    }
    return array;
}

// Returns the identity
- (SecIdentityRef)getClientCertificate {
    SecIdentityRef identityApp = nil;
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectoryPath = [paths objectAtIndex:0];
    NSString *myFilePath = [documentsDirectoryPath stringByAppendingPathComponent:@"file12.p12"]; 
    NSData *PKCS12Data = [NSData dataWithContentsOfFile:myFilePath];

    CFDataRef inPKCS12Data = (__bridge CFDataRef)PKCS12Data;
    CFStringRef password = CFSTR("password");
    const void *keys[] = { kSecImportExportPassphrase };//kSecImportExportPassphrase };
    const void *values[] = { password };
    CFDictionaryRef options = CFDictionaryCreate(NULL, keys, values, 1, NULL, NULL);
    CFArrayRef items = CFArrayCreate(NULL, 0, 0, NULL);
    OSStatus securityError = SecPKCS12Import(inPKCS12Data, options, &items);
    CFRelease(options);
    CFRelease(password);
    if (securityError == errSecSuccess) {
        NSLog(@"Success opening p12 certificate. Items: %ld", CFArrayGetCount(items));
        CFDictionaryRef identityDict = CFArrayGetValueAtIndex(items, 0);
        identityApp = (SecIdentityRef)CFDictionaryGetValue(identityDict, kSecImportItemIdentity);
    } else {
        NSLog(@"Error opening Certificate.");
    }

    return identityApp;
}

- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {
    if ([challenge previousFailureCount] == 0) {
        SecIdentityRef identity = [self getClientCertificate];  // Go get a SecIdentityRef
        CFArrayRef certs = [self getCertificate:identity]; // Get an array of certificates
        // Convert the CFArrayRef to a NSArray
        NSArray *myArray = (__bridge NSArray *)certs;

        // Create the NSURLCredential
        NSURLCredential *newCredential = [NSURLCredential credentialWithIdentity:identity certificates:myArray persistence:NSURLCredentialPersistencePermanent];

        // Send
        [challenge.sender useCredential:newCredential forAuthenticationChallenge:challenge];    
    } else {
        // Failed
        [[challenge sender] cancelAuthenticationChallenge:challenge];
    }
}

- (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace
{
    return YES;
}

In both cases I can't autheticate the client. Moreover I also installed the server.crt certificate on the device (iPhone/iPad) but I keep receiving "Error Domain=NSURLErrorDomain Code=-1200".

Any ideas? Thank you.

Answer 1

The code I wrote works perfectly, the problem was server side.