NSUrlConnection sendAsynchronousRequest and self-signed certificates - ios

Question

I'm writing some API code that does http requests, and I've been using [NSUrlConnection:sendAsynchronousRequest:queue:completionHandler] for the calls, as it makes it pretty easy to write simple handlers, and also so that I don't have to have different classes with different delegates for each call.
The problem that I'm having is that it seems that the only way to accept self-signed certificates is to have a delegate that implements a couple of functions saying that the certificate is okay. Is there any way to do this with the asynchronous method that uses blocks?

Answer 1

No, but the delegate calls are not all that hard. This is the code you need:
1) Make this a file static
static CFArrayRef certs;
2) DO this in your initialize:
// I had a crt certificate, needed a der one, so found this site:
// http://fixunix.com/openssl/537621-re-der-crt-file-conversion.html
// and did this from Terminal: openssl x509 -in crt.crt -outform der -out crt.der
NSString *path = [[NSBundle mainBundle] pathForResource:#"<your name>" ofType:#"der"];
assert(path);
NSData *data = [NSData dataWithContentsOfFile:path];
assert(data);
SecCertificateRef rootcert = SecCertificateCreateWithData(NULL, (__bridge CFDataRef)data);
if(rootcert) {
const void *array[1] = { rootcert };
certs = CFArrayCreate(NULL, array, 1, &kCFTypeArrayCallBacks);
CFRelease(rootcert); // for completeness, really does not matter
} else {
NSLog(#"BIG TROUBLE - ROOT CERTIFICATE FAILED!");
}
3) Then add this method:
- (void)connection:(NSURLConnection *)conn didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{
#pragma unused(conn)
// NSLog(#"didReceiveAuthenticationChallenge %# FAILURES=%zd", [[challenge protectionSpace] authenticationMethod], (ssize_t)[challenge previousFailureCount]);
/* Setup */
NSURLProtectionSpace *protectionSpace = [challenge protectionSpace];
assert(protectionSpace);
SecTrustRef trust = [protectionSpace serverTrust];
assert(trust);
CFRetain(trust); // Don't know when ARC might release protectionSpace
NSURLCredential *credential = [NSURLCredential credentialForTrust:trust];
BOOL trusted = NO;
OSStatus err;
SecTrustResultType trustResult = 0;
err = SecTrustSetAnchorCertificates(trust, certs);
if (err == noErr) {
err = SecTrustEvaluate(trust, &trustResult);
if(err == noErr) {
// http://developer.apple.com/library/mac/#qa/qa1360/_index.html
switch(trustResult) {
case kSecTrustResultProceed:
case kSecTrustResultConfirm:
case kSecTrustResultUnspecified:
trusted = YES;
break;
}
}
}
CFRelease(trust);
// Return based on whether we decided to trust or not
if (trusted) {
[[challenge sender] useCredential:credential forAuthenticationChallenge:challenge];
} else {
NSLog(#"Trust evaluation failed");
[[challenge sender] cancelAuthenticationChallenge:challenge];
}
}