I have the somewhat unusual use case and apple's useCredential:forAuthenticationChallenge can't cope (or maybe it's me?).
The issue is, that I am making two consecutive connections (the second is called after the first one has been completed) each with different credentials (different client certificate):
[[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
URLs of requests are:
https://my.url.com/ws/service1
https://my.url.com/ws/service2
Then I implement the delegate's method:
- (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {
if ([challenge previousFailureCount] != 0) {
[[challenge sender] cancelAuthenticationChallenge:challenge];
}
NSURLCredential *newCredential = nil;
NSURLProtectionSpace *protectionSpace = [challenge protectionSpace];
if ([protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodClientCertificate]) {
if (isFirstRequest) {
[[challenge sender] useCredential:credentials1 forAuthenticationChallenge:challenge];
} else {
[[challenge sender] useCredential:credentials2 forAuthenticationChallenge:challenge];
}
}
}
Credentials are created from identity (persistence flag has no effect whatsoever):
NSURLCredential* credential = [NSURLCredential credentialWithIdentity:identityRef
certificates:certificates
persistence:NSURLCredentialPersistenceNone];
I'm sure that both credentials are valid and that they should be working. But only the first call is successful. After that when the second request is made, willSendRequestForAuthenticationChallenge method is called and the correct useCredential:forAuthenticationChallange is called but it does not change the credentials and the first ones are used anyway!
From the documentation of - useCredential:forAuthenticationChallenge:
Attempt to use a given credential for a given authentication challenge. (required)
This method has no effect if it is called with an authentication challenge that has already been handled.
Is there a way to check if the challenge has already been handled or to reset the challenge so that the system does not use any cached credentials?
I already tried to erase cached credentials but the code below (from SO) always returned zero credentials:
- (void)eraseCredentials {
NSString *urlString = #"my.url.com";
NSURLCredentialStorage *credentialsStorage = [NSURLCredentialStorage sharedCredentialStorage];
NSDictionary *allCredentials = [credentialsStorage allCredentials];
if ([allCredentials count] > 0)
{
for (NSURLProtectionSpace *protectionSpace in allCredentials)
{
if ([[protectionSpace host] isEqualToString:urlString])
{
NSDictionary *credentials = [credentialsStorage credentialsForProtectionSpace:protectionSpace];
for (NSString *credentialKey in credentials)
{
[credentialsStorage removeCredential:[credentials objectForKey:credentialKey] forProtectionSpace:protectionSpace];
}
}
}
}
}
Note: What I already tried is to add the . or # after the URL as mentioned in TLS Session Cache or here at StackOverflow but I don't think that's the issue here because my willSendRequestForAuthenticationChallenge is called correctly multiple times as expected...jest the given credentials doesn't work.
Update: the request itself is being built as follows:
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[self resourceURLWithName:name]
cachePolicy:NSURLRequestReloadIgnoringCacheData
timeoutInterval:30];
[request setHTTPShouldHandleCookies:NO];
Previously it was only:
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[self resourceURLWithName:name]];
But there was no change in behaviour.
Update 2: In the end it wasn't issue with useCredential:forAuthenticationChallenge: but it was an issue with identities. The one I used seemed to be ok but it wasn't. See my answer in this SO question
Implement below delegate method
- (BOOL)connectionShouldUseCredentialStorage:(NSURLConnection *)connection
{
return NO;
}
Here's an issue: I need to implement both HTTP basic authorization and MS NTLM authorization. I use asynchronous NSURLConnection so I receive
-(void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
callback. The full code of this method looks like that:
-(void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{
NSString* authMethod = [[challenge protectionSpace] authenticationMethod];
NSLog(#"Authentication method: %#", authMethod);
NSString *userName = self.login;
if ([authMethod isEqualToString:NSURLAuthenticationMethodNTLM]) {
userName = [userName lastElementAfterSlash];
}
else if ([authMethod isEqualToString:NSURLAuthenticationMethodNegotiate]) {
userName = [NSString stringWithFormat:#"%##%#", userName, self.url.host];
}
if ([challenge previousFailureCount] <= 1) {
NSURLCredential *credential = [NSURLCredential credentialWithUser:userName password:self.password persistence:NSURLCredentialPersistenceForSession];
[[challenge sender] useCredential:credential forAuthenticationChallenge:challenge];
NSURLProtectionSpace *protectionSpace = [[NSURLProtectionSpace alloc]
initWithHost:[self.url host]
port:0
protocol:self.url.scheme
realm:[self.url host]
authenticationMethod:authMethod];
[[NSURLCredentialStorage sharedCredentialStorage] setDefaultCredential:credential
forProtectionSpace:protectionSpace];
}
else {
NSLog(#"Authentication error");
NSLog(#"Failed login with status code: %d", [(NSHTTPURLResponse*)[challenge failureResponse]statusCode]);
[[challenge sender] cancelAuthenticationChallenge:challenge];
}
}
The two global issues I've met so far using this method:
1) As per Charles sniffer, all the requests to the server are doubled (as per Apple Docs, it's an expected behaviour). However, it leads to lack of performance (two requests instead of just one) comparing to setting header directly, using setValue:forHTTPHeader:.
2) It's being called not for every request. For example, when I'm trying to grab an image from server, it returns 302 (redirect to login web page) HTTP code instead of 401 HTTP code, so this does not work at all.
What I want to accomplish, is to grab the correct Authorization header once and then put it manually in every subsequent NSMutableURLRequest I make. I can compose HTTP Basic authorization manually, it's pretty simple, but I can't compose NTLM header in the same manner, that's why I was relying on didReceiveAuthenticationChallenge: method.
Could you please point me out, how can I receive the Authorization header, that is set automatically by NSURLProtectionSpace, so each request will INITIALLY go authorized?
P.S. I tried to receive it from
[connection.currentRequest allHTTPHeaderFields];
but it returns an empty array. I'm fighting with that for more than two days, any help will be kindly appreciated!
I am developing iOS Application. We have custom certificate authority with self-signed ca-cert. Certification authority issues certificates both for users and for https server too. I would like to create iOS application which can authenticate https server using ca certificate and also can communicate to https server using client certificate. I already have the code for communicating with https server using client certificate, but I need to have ca-certificate imported to system keyring. I would like to have ca certificate hard-coded into application. My code looks like this:
- (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace {
bool result=NO;
if ([protectionSpace authenticationMethod] == NSURLAuthenticationMethodServerTrust) {
result= YES;
} else if([protectionSpace authenticationMethod] == NSURLAuthenticationMethodClientCertificate) {
result = YES;
}
return result;
}
- (BOOL)shouldTrustProtectionSpace:(NSURLProtectionSpace *)protectionSpace {
CFDataRef certDataRef = (__bridge_retained CFDataRef)self.rootCertData;
SecCertificateRef cert = SecCertificateCreateWithData(NULL, certDataRef);
SecTrustRef serverTrust = protectionSpace.serverTrust;
CFArrayRef certArrayRef = CFArrayCreate(NULL, (void *)&cert, 1, NULL);
SecTrustSetAnchorCertificates(serverTrust, certArrayRef);
SecTrustResultType trustResult;
SecTrustEvaluate(serverTrust, &trustResult);
return trustResult == kSecTrustResultUnspecified;
}
- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {
NSLog(#"Did receive auth challange %#",[challenge debugDescription]);
NSURLProtectionSpace *protectionSpace = [challenge protectionSpace];
NSString *authMethod = [protectionSpace authenticationMethod];
if(authMethod == NSURLAuthenticationMethodServerTrust ) {
NSLog(#"Verifying The Trust");
NSURLCredential* cred=[NSURLCredential credentialForTrust:[protectionSpace serverTrust]];
if ([self shouldTrustProtectionSpace:challenge.protectionSpace]) {
[[challenge sender] useCredential:cred forAuthenticationChallenge:challenge];
NSLog(#"OK");
} else {
NSLog(#"FAILED");
[challenge.sender performDefaultHandlingForAuthenticationChallenge:challenge];
}
}
if(authMethod == NSURLAuthenticationMethodClientCertificate ) {
NSLog(#"Trying Certificate");
.....
Everything works like a charm, until server does not require client certificate. At this moment I will receive error The certificate for this server is invalid and execution will never reach point
NSLog(#"Trying Certificate");
When I have .der ca-cert loaded into system keyring, everything works, even client certificate is sent to server, and server can recognize user. I thing that
SecTrustSetAnchorCertificates(serverTrust, certArrayRef);
affects somehow trust, cause when I skip this call, I can simply do:
[[challenge sender] useCredential:cred forAuthenticationChallenge:challenge];
without any error, but I'm not able to verify certificate in this case.
What am I doing wrong?
Big thanks,
Adam
Have a look at this code
https://github.com/dirkx/Security-Pinning-by-CA
which does both by fairly carefully keeping the two trust blocks separate (which you seem to be mixing).
I'm trying to get the three above working properly, and something is not clicking. Specifically, the authentication request is not being triggered when it appears it should be. According to what I've read here, the relevant pieces are:
- (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace
{
NSLog(#"protection space");
return [protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust];
}
- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{
NSLog(#"auth challenge");
NSInteger count = [challenge previousFailureCount];
if (count > 0)
{
NSLog(#"count > 0");
NSObject<ServiceDelegate> *delegate = [currentRequest delegate];
[[challenge sender] cancelAuthenticationChallenge:challenge];
if ([delegate respondsToSelector:#selector(wrapperHasBadCredentials:)])
{
[delegate rbService:self wrapperHasBadCredentials:self];
}
return;
}
NSArray *trustedHosts = [[NSArray alloc] initWithObjects:#"myserver", nil];
if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust])
{
NSLog(#"server trust");
if ([trustedHosts containsObject:challenge.protectionSpace.host])
{
[challenge.sender useCredential:[NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust] forAuthenticationChallenge:challenge];
}
[challenge.sender continueWithoutCredentialForAuthenticationChallenge:challenge];
}
else
{
NSLog(#"credentials");
NSURLCredential* credential = [[[NSURLCredential alloc] initWithUser:#"xxx" password:#"xxx" persistence:NSURLCredentialPersistenceForSession] autorelease];
[[challenge sender] useCredential:credential forAuthenticationChallenge:challenge];
}
}
The target server is set up for two URLS, one HTTPS and one HTTP, both of which prompt for username/password using basic authentication. I've checked the target server using firefox and everything seems to work as advertised. The target server uses an untrusted cert, but I thought I'd taken care of that in the code. Maybe not.
The specific behavior in the application:
When using HTTP the log reads:
log - protection space
(then returns 401 code)
When using HTTPS:
log - protection space
log - auth challenge
log - server trust
log - protection space
(then returns a 401 code)
In the first instance, it gets to the canAuthenticate... section, returns, but then doesn't challenge for the authentication, and returns a 401 response.
In the second instance, it does all that, actually does challenge, then goes to the canAuthenticate... section again, returns, and returns a 401 response.
Keep in mind that the request is a POST request, complete with headers and an HTTPBody. The authentication is not included in the headers (I would rather not do that), but if there is no other solution I will try things that way.
As always, thank you very much for the help. It's priceless.
It looks like the answer here has to be sending the authentication along with the POST request. I was thinking that the challenge/response process would somehow add those headers to the request by itself, but apparently not.
I have the following simple code to connect to a SSL webpage
NSMutableURLRequest *urlRequest=[NSMutableURLRequest requestWithURL:url];
[ NSURLConnection sendSynchronousRequest: urlRequest returningResponse: nil error: &error ];
Except it gives an error if the cert is a self signed one Error Domain=NSURLErrorDomain Code=-1202 UserInfo=0xd29930 "untrusted server certificate". Is there a way to set it to accept connections anyway (just like in a browser you can press accept) or a way to bypass it?
There is a supported API for accomplishing this! Add something like this to your NSURLConnection delegate:
- (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace {
return [protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust];
}
- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {
if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust])
if ([trustedHosts containsObject:challenge.protectionSpace.host])
[challenge.sender useCredential:[NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust] forAuthenticationChallenge:challenge];
[challenge.sender continueWithoutCredentialForAuthenticationChallenge:challenge];
}
Note that connection:didReceiveAuthenticationChallenge: can send its message to challenge.sender (much) later, after presenting a dialog box to the user if necessary, etc.
If you're unwilling (or unable) to use private APIs, there's an open source (BSD license) library called ASIHTTPRequest that provides a wrapper around the lower-level CFNetwork APIs. They recently introduced the ability to allow HTTPS connections using self-signed or untrusted certificates with the -setValidatesSecureCertificate: API. If you don't want to pull in the whole library, you could use the source as a reference for implementing the same functionality yourself.
Ideally, there should only be two scenarios of when an iOS application would need to accept an un-trusted certificate.
Scenario A: You are connected to a test environment which is using a self-signed certificate.
Scenario B: You are Proxying HTTPS traffic using a MITM Proxy like Burp Suite, Fiddler, OWASP ZAP, etc. The Proxies will return a certificate signed by a self-signed CA so that the proxy is able to capture HTTPS traffic.
Production hosts should never use un-trusted certificates for obvious reasons.
If you need to have the iOS simulator accept an un-trusted certificate for testing purposes it is highly recommended that you do not change application logic in order disable the built in certificate validation provided by the NSURLConnection APIs. If the application is released to the public without removing this logic, it will be susceptible to man-in-the-middle attacks.
The recommended way to accept un-trusted certificates for testing purposes is to import the Certificate Authority(CA) certificate which signed the certificate onto your iOS Simulator or iOS device. I wrote up a quick blog post which demonstrates how to do this which an iOS Simulator at:
accepting untrusted certificates using the ios simulator
NSURLRequest has a private method called setAllowsAnyHTTPSCertificate:forHost:, which will do exactly what you'd like. You could define the allowsAnyHTTPSCertificateForHost: method on NSURLRequest via a category, and set it to return YES for the host that you'd like to override.
To complement the accepted answer, for much better security, you could add your server certificate or your own root CA certificate to keychain( https://stackoverflow.com/a/9941559/1432048), however doing this alone won't make NSURLConnection authenticate your self-signed server automatically. You still need to add the below code to your NSURLConnection delegate, it's copied from Apple sample code AdvancedURLConnections, and you need to add two files(Credentials.h, Credentials.m) from apple sample code to your projects.
- (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace {
return [protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust];
}
- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {
if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]) {
// if ([trustedHosts containsObject:challenge.protectionSpace.host])
OSStatus err;
NSURLProtectionSpace * protectionSpace;
SecTrustRef trust;
SecTrustResultType trustResult;
BOOL trusted;
protectionSpace = [challenge protectionSpace];
assert(protectionSpace != nil);
trust = [protectionSpace serverTrust];
assert(trust != NULL);
err = SecTrustEvaluate(trust, &trustResult);
trusted = (err == noErr) && ((trustResult == kSecTrustResultProceed) || (trustResult == kSecTrustResultUnspecified));
// If that fails, apply our certificates as anchors and see if that helps.
//
// It's perfectly acceptable to apply all of our certificates to the SecTrust
// object, and let the SecTrust object sort out the mess. Of course, this assumes
// that the user trusts all certificates equally in all situations, which is implicit
// in our user interface; you could provide a more sophisticated user interface
// to allow the user to trust certain certificates for certain sites and so on).
if ( ! trusted ) {
err = SecTrustSetAnchorCertificates(trust, (CFArrayRef) [Credentials sharedCredentials].certificates);
if (err == noErr) {
err = SecTrustEvaluate(trust, &trustResult);
}
trusted = (err == noErr) && ((trustResult == kSecTrustResultProceed) || (trustResult == kSecTrustResultUnspecified));
}
if(trusted)
[challenge.sender useCredential:[NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust] forAuthenticationChallenge:challenge];
}
[challenge.sender continueWithoutCredentialForAuthenticationChallenge:challenge];
}
I can't take any credit for this, but this one I found worked really well for my needs. shouldAllowSelfSignedCert is my BOOL variable. Just add to your NSURLConnection delegate and you should be rockin for a quick bypass on a per connection basis.
- (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)space {
if([[space authenticationMethod] isEqualToString:NSURLAuthenticationMethodServerTrust]) {
if(shouldAllowSelfSignedCert) {
return YES; // Self-signed cert will be accepted
} else {
return NO; // Self-signed cert will be rejected
}
// Note: it doesn't seem to matter what you return for a proper SSL cert
// only self-signed certs
}
// If no other authentication is required, return NO for everything else
// Otherwise maybe YES for NSURLAuthenticationMethodDefault and etc.
return NO;
}
In iOS 9, SSL connections will fail for all invalid or self-signed certificates. This is the default behavior of the new App Transport Security feature in iOS 9.0 or later, and on OS X 10.11 and later.
You can override this behavior in the Info.plist, by setting NSAllowsArbitraryLoads to YES in the NSAppTransportSecurity dictionary. However, I recommend overriding this setting for testing purposes only.
For information see App Transport Technote here.
The category workaround posted by Nathan de Vries will pass the AppStore private API checks, and is useful in cases where you do not have control of the NSUrlConnection object.
One example is NSXMLParser which will open the URL you supply, but does not expose the NSURLRequest or NSURLConnection.
In iOS 4 the workaround still seems to work, but only on the device, the Simulator does not invoke the allowsAnyHTTPSCertificateForHost: method anymore.
You have to use NSURLConnectionDelegate to allow HTTPS connections and there are new callbacks with iOS8.
Deprecated:
connection:canAuthenticateAgainstProtectionSpace:
connection:didCancelAuthenticationChallenge:
connection:didReceiveAuthenticationChallenge:
Instead those, you need to declare:
connectionShouldUseCredentialStorage: - Sent to determine whether the URL loader should use the credential storage for authenticating the connection.
connection:willSendRequestForAuthenticationChallenge: - Tells the delegate that the connection will send a request for an authentication challenge.
With willSendRequestForAuthenticationChallenge you can use challenge like you did with the deprecated methods, for example:
// Trusting and not trusting connection to host: Self-signed certificate
[challenge.sender useCredential:[NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust] forAuthenticationChallenge:challenge];
[challenge.sender continueWithoutCredentialForAuthenticationChallenge:challenge];
I posted some gist code (based on someone else's work which I note) that lets you properly authenticate against a self generated certificate (and how to get a free certificate - see comments bottom of Cocoanetics)
My code is here github
You can use this Code
-(void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{
if ([[challenge protectionSpace] authenticationMethod] == NSURLAuthenticationMethodServerTrust)
{
[[challenge sender] useCredential:[NSURLCredential credentialForTrust:[[challenge protectionSpace] serverTrust]] forAuthenticationChallenge:challenge];
}
}
Use -connection:willSendRequestForAuthenticationChallenge: instead of these Deprecated Methods
Deprecated:
-(BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace
-(void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
-(void)connection:(NSURLConnection *)connection didCancelAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
If you want to keep using sendSynchronousRequest i work in this solution:
FailCertificateDelegate *fcd=[[FailCertificateDelegate alloc] init];
NSURLConnection *c=[[NSURLConnection alloc] initWithRequest:request delegate:fcd startImmediately:NO];
[c setDelegateQueue:[[NSOperationQueue alloc] init]];
[c start];
NSData *d=[fcd getData];
you can see it here: Objective-C SSL Synchronous Connection
With AFNetworking I have successfully consumed https webservice with below code,
NSString *aStrServerUrl = WS_URL;
// Initialize AFHTTPRequestOperationManager...
AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
manager.requestSerializer = [AFJSONRequestSerializer serializer];
manager.responseSerializer = [AFJSONResponseSerializer serializer];
[manager.requestSerializer setValue:#"application/json" forHTTPHeaderField:#"Content-Type"];
manager.securityPolicy.allowInvalidCertificates = YES;
[manager POST:aStrServerUrl parameters:parameters success:^(AFHTTPRequestOperation *operation, id responseObject)
{
successBlock(operation, responseObject);
} failure:^(AFHTTPRequestOperation *operation, NSError *error)
{
errorBlock(operation, error);
}];