Question

这是我使用自签名证书进行身份验证的非常标准的NSURLConnection回调：

- (SecCertificateRef)certRefFromDerNamed:(NSString*)derFileName resultingDataRef:(CFDataRef*)dataRefPtr{
    NSString *thePath = [[NSBundle mainBundle] pathForResource:derFileName ofType:@"der"];
    NSData *certData = [[NSData alloc] initWithContentsOfFile:thePath];
    CFDataRef certDataRef = (__bridge_retained CFDataRef)certData;
    SecCertificateRef cert = SecCertificateCreateWithData(NULL, certDataRef);
    *dataRefPtr = certDataRef;
    return cert;
}

- (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {

if (connection == self.connection) {

    BOOL trusted = NO;
     if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]) {

        SecPolicyRef policyRef = SecPolicyCreateBasicX509();

        SecCertificateRef cert1;
        CFDataRef certData1;

        cert1 = [self certRefFromDerNamed:@"some3rdpartycacert" resultingDataRef:&certData1];

        SecCertificateRef certArray[1] = { cert1 };
        CFArrayRef certArrayRef = CFArrayCreate(NULL, (void *)certArray, 1, NULL);

        SecTrustRef serverTrust = challenge.protectionSpace.serverTrust;
        SecTrustSetAnchorCertificates(serverTrust, certArrayRef);
        SecTrustResultType trustResult;

        SecTrustEvaluate(serverTrust, &trustResult);

        trusted = (trustResult == kSecTrustResultUnspecified);

        CFRelease(certArrayRef);
        CFRelease(policyRef);
        CFRelease(cert1);
        CFRelease(certData1);
    }
    if (trusted) {
        [challenge.sender useCredential:[NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust] forAuthenticationChallenge:challenge];
    } else {
        [challenge.sender performDefaultHandlingForAuthenticationChallenge:challenge];
    }
}
}

trustResult始终为kSecTrustResultRecoverableTrustFailure。

证书本身有点问题。根据服务器上的curl cert主题名称与我正在连接的url不匹配。我已经联系了第三方公司，他们告诉我，我需要在我的代码中接受这个url不匹配。问题是我不知道如何在iOS上这样做。我可以完全绕过证书检查（只需假设trusted=YES并调用useCredential）或完全失败。从安全角度来看，第一种解决方案显然是错误的，并且容易受到MITM攻击。

这是CURL输出（我在这里使用了相同证书的PEM版本）：

ukaszs-iMac:Preferences lukasz$  curl --verbose --cacert ~/Desktop/some3rdpartycacert.txt  https://dev-service.some3rdparty.com:50101/
* About to connect() to dev-service.some3rdparty.com port 50101 (#0)
*   Trying XXX.XXX.XXX.XXX...
* connected
* Connected to dev-service.some3rdparty.com (XXX.XXX.XXX.XXX) port 50101 (#0)
* successfully set certificate verify locations:
*   CAfile: /Users/lukasz/Desktop/some3rdpartycacert.txt
  CApath: none
* SSLv3, TLS handshake, Client hello (1):
* SSLv3, TLS handshake, Server hello (2):
* SSLv3, TLS handshake, CERT (11):
* SSLv3, TLS handshake, Request CERT (13):
* SSLv3, TLS handshake, Server finished (14):
* SSLv3, TLS handshake, CERT (11):
* SSLv3, TLS handshake, Client key exchange (16):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
* SSL connection using AES256-SHA
* Server certificate:
*    subject: C=CA; ST=Ontario; O=Some 3rdParty Corporation; CN=otherpage.some3rdparty.com; emailAddress=noc@some3rdparty.com
*    start date: 2013-10-30 16:52:14 GMT
*    expire date: 2013-10-30 16:52:14 GMT
* SSL: certificate subject name 'otherpage.some3rdparty.com' does not match target host name 'dev-service.some3rdparty.com'
* Closing connection #0
* SSLv3, TLS alert, Client hello (1):
curl: (51) SSL: certificate subject name 'otherpage.some3rdparty.com' does not match target host name 'dev-service.some3rdparty.com'

那么，如何忽略iOS上的这个特定错误？

Answer 1

您需要使用实际主机名创建特殊策略，然后从中创建并评估serverTrust。大致是：

SecPolicyRef policyRef = SecPolicyCreateSSL(true, CFSTR("otherpage.some3rdparty.com"));

OSStatus    status;
SecTrustRef serverTrust;
status = SecTrustCreateWithCertificates(certificatesFromOriginalServerTrust, policyRef, & serverTrust);
// noErr == status?

status = SecTrustSetAnchorCertificates(serverTrust, certArrayRef);
// noErr == status?

SecTrustResultType trustResult;
status = SecTrustEvaluate(serverTrust, &trustResult);
// noErr == status?

if(kSecTrustResultProceed == trustResult || kSecTrustResultUnspecified == trustResult) {
    // all good
}

P.S。你没有使用你创建的政策。

我刚刚找到了更完整的解释here。

Answer 2

对于这个特定问题，您需要阅读 “iOS 5编程推动极限：为Apple iPhone，iPad和iPod Touch开发非凡的移动应用程序”一书。（Rob Napier，Mugunth Kumar）

在本书的第219页底部，它说： “如果您对传递的名称感到满意，则将证书重新评估为简单的X.509证书，而不是作为SSL握手的一部分（即，在忽略主机名的情况下对其进行评估）”

然后它有一个特殊的RNSecTrustEvaluateAsX509函数。因此，实际上使用该函数评估证书时忽略主机名部分并将该部分设置为“受信任”。请参阅http://bit.ly/1g1RzdF（转至第219页）

书中的代码可以在这里找到： https://github.com/iosptl/ios5ptl/blob/master/ch11/Connection/Connection/ConnectionViewController.m

对于具有不匹配主题名称的自签名CA，SecTrustEvaluate失败并显示kSecTrustResultRecoverableTrustFailure

2 个答案: