支持 SSL / TLS 的 Objective-C TCP 服务器

Question

我有一个简单的 TCP 服务器/客户端设置。这种连接实际上效果很好。

现在我想为套接字连接实现 SSL / TLS 加密。我使用钥匙串访问创建了一个 PKCS12 证书。在我的服务器中，我在接受回调中有以下代码：

NSString *certificatePath = [[NSBundle mainBundle] pathForResource:@"TCPServerCertificate" ofType:@"p12"];
NSData *certificateData = [NSData dataWithContentsOfFile:certificatePath];

CFArrayRef keyRef;
OSStatus status = SecPKCS12Import((__bridge CFDataRef)certificateData, (__bridge CFDictionaryRef)@{(__bridge NSString *)kSecImportExportPassphrase: @"1234"}, &keyRef);

if (status != noErr) {
    NSLog(@"PKCS12 import error %i", status);
    return;
}

CFDictionaryRef identityDict = CFArrayGetValueAtIndex(keyRef, 0);
SecIdentityRef identityRef = (SecIdentityRef)CFDictionaryGetValue(identityDict, kSecImportItemIdentity);

SecCertificateRef certificate;
status = SecIdentityCopyCertificate(identityRef, &certificate);

if (status != noErr) {
    NSLog(@"sec identity copy failed: %i", status);
    return;
}

NSArray *certificates = [NSArray arrayWithObjects:(__bridge id)identityRef, (__bridge id)certificate, nil];

NSDictionary *settings = @{(NSString *)kCFStreamPropertyShouldCloseNativeSocket:    [NSNumber numberWithBool:YES],
                           (NSString *)kCFStreamSSLValidatesCertificateChain:       [NSNumber numberWithBool:YES],
                           (NSString *)kCFStreamSSLAllowsExpiredCertificates:       [NSNumber numberWithBool:NO],
                           (NSString *)kCFStreamSSLAllowsExpiredRoots:              [NSNumber numberWithBool:NO],
                           (NSString *)kCFStreamSSLAllowsAnyRoot:                   [NSNumber numberWithBool:YES],
                           (NSString *)kCFStreamSSLCertificates:                    certificates,
                           (NSString *)kCFStreamSSLIsServer:                        [NSNumber numberWithBool:YES],
                           (NSString *)kCFStreamSSLLevel:                           (NSString *)kCFStreamSocketSecurityLevelTLSv1};

CFReadStreamSetProperty(readStream, kCFStreamPropertySSLSettings, (CFTypeRef)settings);
CFWriteStreamSetProperty(writeStream, kCFStreamPropertySSLSettings, (CFTypeRef)settings);

然后我创建流的NSStream 实例并在另一个类中处理它们。

当我运行服务器并连接客户端时，我的委托中得到了常规的NSStreamEventOpenCompleted。如果我只是关闭连接，然后尝试写入流或事件，我会收到以下错误：

2013-10-25 13:27:08.584 TCPServer[6435:303] CFNetwork SSLHandshake failed (-9800)
2013-10-25 13:27:08.584 TCPServer[6435:303] NSStreamEventOpenCompleted
2013-10-25 13:27:08.585 TCPServer[6435:303] NSStreamEventErrorOccurred

我想知道我必须在客户端实现什么。另外我想知道为什么在发送数据或从客户端断开连接时握手失败。每当发生此错误时，客户端都会认为它仍然处于连接状态。

是否有任何好的 TCP SSL/TLS 教程或其他涵盖客户端和服务器端的材料？

Answer 1

这段代码有一些问题： 您不能使用 kCFStreamPropertySSLSettings 设置 kCFStreamPropertyShouldCloseNativeSocket，并且您不应混合使用服务器和客户端代码。

对于服务器，你应该只设置一个证书

CFReadStreamSetProperty(read, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
CFWriteStreamSetProperty(write, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
//kCFStreamPropertySocketSecurityLevel
//Note: If you set this key, you must do so before setting any other SSL options, such as kCFStreamPropertySSLSettings.
CFReadStreamSetProperty(read, kCFStreamPropertySocketSecurityLevel, kCFStreamSocketSecurityLevelNegotiatedSSL);
CFWriteStreamSetProperty(write, kCFStreamPropertySocketSecurityLevel, kCFStreamSocketSecurityLevelNegotiatedSSL);
//Creating server dictionnary

//kCFStreamSSLIsServer
//If the value of this key is kCFBooleanTrue, the kCFStreamSSLCertificates key must contain a valid value

//kCFStreamSSLCertificates
//Security property key whose value is a CFArray of SecCertificateRefs except for the first element in the array, which is a SecIdentityRef.
//For more information, see SSLSetCertificate() in Security/SecureTransport.h.

NSDictionary *settings = @{(id)kCFStreamSSLCertificates:                    certificates,
                           (id)kCFStreamSSLIsServer:                        @YES};


//Apply settings
CFReadStreamSetProperty(read, kCFStreamPropertySSLSettings, (__bridge CFDictionaryRef)(settings));
CFWriteStreamSetProperty(write, kCFStreamPropertySSLSettings, (__bridge CFDictionaryRef)(settings));

对于客户端，如果您想覆盖验证链 (See Apple doc on overriding chain validation)，您应该执行以下操作：

CFReadStreamSetProperty(read, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
CFWriteStreamSetProperty(write, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
//kCFStreamPropertySocketSecurityLevel
//Note: If you set this key, you must do so before setting any other SSL options, such as kCFStreamPropertySSLSettings.

CFReadStreamSetProperty(read, kCFStreamPropertySocketSecurityLevel, kCFStreamSocketSecurityLevelNegotiatedSSL);
CFWriteStreamSetProperty(write, kCFStreamPropertySocketSecurityLevel, kCFStreamSocketSecurityLevelNegotiatedSSL);

//DO NOT USE kCFStreamPropertySSLContext as it overrides the following configuration
//create dictionnary for kCFStreamPropertySSLSettings

//keys for dictionnary we want to change:kCFStreamSSLAllowsExpiredCertificates;kCFStreamSSLAllowsExpiredRoots;kCFStreamSSLAllowsAnyRoot;
//kCFStreamSSLValidatesCertificateChain => no need to worry about the root
//kCFStreamSSLPeerName kCFNull prevents name verification


settings = @{(id)kCFStreamSSLValidatesCertificateChain: @NO,//The delegate will verify this
             (id)kCFStreamSSLPeerName: (id)kCFNull};//prevents name verification if server is not fixed (eg. IP)

//Apply settings
CFReadStreamSetProperty(read, kCFStreamPropertySSLSettings, (__bridge CFDictionaryRef)(settings));
CFWriteStreamSetProperty(write, kCFStreamPropertySSLSettings, (__bridge CFDictionaryRef)(settings));

Answer 2

我刚刚创建了一个包，它通过新的 iOS 13 限制使 TLS/TCP 更容易。希望它可以帮助某人！随意贡献：

https://github.com/eamonwhiter73/IOSObjCWebSockets