iOS：在钥匙串中预安装 SSL 证书 - 以编程方式

Question

我想在用户访问该网站之前在钥匙串中安装/保存证书。 我有一个 HTTPS 服务器，我的应用程序在用户访问 https://mysite 之前对用户进行身份验证。

有没有办法可以通过钥匙串中的 POST 请求安装/保存证书，或者可以将该证书（文件）复制到资源包以将其标记为可信？

Answer 1

一旦您拥有 der 格式的服务器证书，您可以尝试以下代码：

+ (void) addCertToKeychain:(NSData*)certInDer
{
    OSStatus            err = noErr;
    SecCertificateRef   cert;

    cert = SecCertificateCreateWithData(NULL, (CFDataRef) certInDer);
    assert(cert != NULL);

    CFTypeRef result;

    NSDictionary* dict = [NSDictionary dictionaryWithObjectsAndKeys:
                          (id)kSecClassCertificate, kSecClass,
                          cert, kSecValueRef, 
                          nil];

    err = SecItemAdd((CFDictionaryRef)dict, &result);
    assert(err == noErr || err == errSecDuplicateItem);

    CFRelease(cert);
}

它将把证书添加到您的应用程序的钥匙串沙箱中，即没有其他应用程序会信任您的证书。

Answer 2

来自： http:// /blog.asolutions.com/2011/02/using-tls-with-self-signed-certificates-or-custom-root-certificates-in-ios/

您有两个可用选项：将服务器的证书添加到钥匙串或手动执行验证。无论您采用哪种方法，您都需要在应用程序中包含 DER 编码的 X.509 公共证书。在下面的示例中，它被命名为“ios-trusted-cert.der”）并用它创建一个 SecCertificateRef。 （如果您的服务器的证书是根证书颁发机构的链的一部分，则您应该安装根证书颁发机构而不是服务器的证书。）

NSBundle *bundle = [NSBundle bundleForClass:[self class]];
NSData *iosTrustedCertDerData =
  [NSData dataWithContentsOfFile:[bundle pathForResource:@"ios-trusted-cert"
                                                    ofType:@"der"]];
SecCertificateRef certificate =
  SecCertificateCreateWithData(NULL,
                               (CFDataRef) iosTrustedCertDerData);

请记住，SecCertificateCreateWithData 遵循内存所有权的创建规则，因此当您不再使用时，必须 CFRelease 它。需要它来避免内存泄漏。

接下来，您可以将证书添加到应用程序的钥匙串中。当您希望 iOS 信任您创建的每个新套接字的证书时，这是合适的。

- (void) useKeychain: (SecCertificateRef) certificate {
  OSStatus err =
    SecItemAdd((CFDictionaryRef) [NSDictionary dictionaryWithObjectsAndKeys:
                                  (id) kSecClassCertificate, kSecClass,
                                  certificate, kSecValueRef,
                                  nil],
               NULL);
  if ((err == noErr) || // success!
    (err == errSecDuplicateItem)) { // the cert was already added.  Success!
    // create your socket normally.
    // This is oversimplified.  Refer to the CFNetwork Guide for more details.
    CFReadStreamRef readStream;
    CFWriteStreamRef writeStream;
    CFStreamCreatePairWithSocketToHost(NULL,
                                       (CFStringRef)@"localhost",
                                       8443,
                                       &readStream,
                                       &writeStream);
    CFReadStreamSetProperty(readStream,
                            kCFStreamPropertySocketSecurityLevel,
                            kCFStreamSocketSecurityLevelTLSv1);
    CFReadStreamOpen(readStream);
    CFWriteStreamOpen(writeStream);
  } else {
    // handle the error.  There is probably something wrong with your cert.
  }
}

如果您只想验证您正在创建的套接字的证书，而不验证应用程序中的其他套接字的证书，则可以手动验证您对证书的信任。首先，创建一个套接字（假设您的服务器与客户端在同一台计算机上侦听端口 8443）并在其 ssl 设置中禁用其证书链验证：

- (void) verifiesManually: (SecCertificateRef) certificate {
  CFReadStreamRef readStream;
  CFWriteStreamRef writeStream;
  CFStreamCreatePairWithSocketToHost(NULL,
                                     (CFStringRef)@"localhost",
                                     8443,
                                     &readStream,
                                     &writeStream);
  // Set this kCFStreamPropertySocketSecurityLevel before
  // setting kCFStreamPropertySSLSettings.
  // Setting kCFStreamPropertySocketSecurityLevel
  // appears to override previous settings in kCFStreamPropertySSLSettings
  CFReadStreamSetProperty(readStream,
                          kCFStreamPropertySocketSecurityLevel,
                          kCFStreamSocketSecurityLevelTLSv1);
  // this disables certificate chain validation in ssl settings.
  NSDictionary *sslSettings =
    [NSDictionary dictionaryWithObjectsAndKeys:
     (id)kCFBooleanFalse, (id)kCFStreamSSLValidatesCertificateChain,
     nil];
  CFReadStreamSetProperty(readStream,
                          kCFStreamPropertySSLSettings,
                          sslSettings);
  NSInputStream *inputStream = (NSInputStream *)readStream;
  NSOutputStream *outputStream = (NSOutputStream *)writeStream;
  [inputStream setDelegate:self];
  [outputStream setDelegate:self];
  [inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop]
                         forMode:NSDefaultRunLoopMode];
  [outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop]
                          forMode:NSDefaultRunLoopMode];
  CFReadStreamOpen(readStream);
  CFWriteStreamOpen(writeStream);
}

然后，当您收到套接字已准备好写入数据的回调时，您可以在向服务器写入任何数据或从服务器读取任何数据之前，应验证对服务器包含的证书的信任。首先 (1)，使用您连接的服务器的主机名创建客户端 SSL 策略。主机名包含在服务器的证书中，以验证 DNS 将您定向到的服务器是您信任的服务器。接下来 (2)，您从套接字获取实际的服务器证书。如果服务器的证书是证书链的一部分，则可能有多个与服务器关联的证书。当您拥有实际的服务器证书时，您可以 (3) 创建信任对象。信任对象代表信任评估的本地上下文。它隔离单独的信任评估，而钥匙串证书适用于所有受信任的套接字。有了信任对象后，您可以（4）设置锚证书，即您信任的证书。最后（5），您可以评估信任对象并发现服务器是否可信。

#pragma mark -
#pragma mark NSStreamDelegate
- (void)stream:(NSStream *)aStream
   handleEvent:(NSStreamEvent)eventCode {
  switch (eventCode) {
    case NSStreamEventNone:
    break;
    case NSStreamEventOpenCompleted:
    break;
    case NSStreamEventHasBytesAvailable:
    break;
    case NSStreamEventHasSpaceAvailable:
      // #1
      // NO for client, YES for server.  In this example, we are a client
      // replace "localhost" with the name of the server to which you are connecting
      SecPolicyRef policy = SecPolicyCreateSSL(NO, CFSTR("localhost"));
      SecTrustRef trust = NULL;
      // #2
      CFArrayRef streamCertificates =
        [aStream propertyForKey:(NSString *) kCFStreamPropertySSLPeerCertificates];
      // #3
      SecTrustCreateWithCertificates(streamCertificates,
                                     policy,
                                     &trust);
      // #4
      SecTrustSetAnchorCertificates(trust,
                                    (CFArrayRef) [NSArray arrayWithObject:(id) self.certificate]);
      // #5
      SecTrustResultType trustResultType = kSecTrustResultInvalid;
      OSStatus status = SecTrustEvaluate(trust, &trustResultType);
      if (status == errSecSuccess) {
        // expect trustResultType == kSecTrustResultUnspecified
        // until my cert exists in the keychain see technote for more detail.
        if (trustResultType == kSecTrustResultUnspecified) {
          NSLog(@"We can trust this certificate! TrustResultType: %d", trustResultType);
        } else {
          NSLog(@"Cannot trust certificate. TrustResultType: %d", trustResultType);
        }
      } else {
        NSLog(@"Creating trust failed: %d", status);
        [aStream close];
      }
      if (trust) {
        CFRelease(trust);
      }
      if (policy) {
        CFRelease(policy);
      }
    break;
    case NSStreamEventErrorOccurred:
      NSLog(@"unexpected NSStreamEventErrorOccurred: %@", [aStream streamError]);
    break;
    case NSStreamEventEndEncountered:
    break;
    default:
    break;
  }
}