双向 TLS 身份验证 - SSLV3_ALERT_UNSUPPORTED_CERTIFICATE

Question

我目前正在尝试在客户端和服务器之间实现双向 TLS 身份验证。我遇到了 SSL 错误，它的描述性不是很强。 StackOverflow 也没有太多与它相关的问题，因为大多数时候它是互联网上的单向 TLS。 但是，据我所知，出现此错误是因为客户端证书有问题，所以下面我附上了与此相关的信息。 如果不是这种情况，请告诉我。

生成客户证书

我客户的 cnf(foo.config) 看起来像（替换所有敏感信息）：

[ req ]
default_bits = 2048
default_md = sha256
prompt = no
req_extensions = req_ext
distinguished_name = dn
encrypt_key = no

[ dn ]
O=Bar
OU=User
CN=myuser@foo.com

[ req_ext ]
subjectAltName = email:myuser@foo.com
nsCertType = client, email, objsign
keyUsage = nonRepudiation, digitalSignature, keyEncipherment

我使用 openssl 传入这个配置文件来创建一个 csr：

openssl req -new -sha256 -key foo.key -out foo.csr -config foo.config

然后我将它发送到内部的基础架构管理 API 以签署 x509 证书。我将客户端证书保存为foo.cert（它包含到 CA 的信任链）。

我的客户如何发送证书

当我向我的服务器发送一个 urllib 打开请求时，我使用我的HTTPSConnection 发送 ssl 上下文：

... # Inside some handler code
context = ssl.create_default_context(purpose=ssl.Purpose.SERVER_AUTH,
            cafile=ROOT_CA)
context.load_cert_chain(certfile=CERT_DEST, keyfile=KEY_DEST)
context.verify_mode = ssl.CERT_REQUIRED
context.check_hostname = True
return http.client.HTTPSConnection(host, context=context)

我的烧瓶服务器如何设置

当我的测试烧瓶服务器像这样接收 ssl 上下文时：

executor = Flask(__name__)
context = ssl.create_default_context(purpose=ssl.Purpose.CLIENT_AUTH, cafile=TEST_CA_CERT)
context.load_cert_chain(certfile=TEST_CERT, keyfile=TEST_KEY)
context.verify_mode = ssl.CERT_REQUIRED
context.check_hostname = False
executor.run(host=host, port=port, ssl_context=context)

它设置自己的证书和密钥文件。它还设置客户端身份验证请求。

完整的错误回溯

在运行时，在通话期间，我得到这个回溯（替换所有敏感信息）：

Traceback (most recent call last):
  File "/auto/foo/python3-rhel6/lib/python3.6/urllib/request.py", line 1318, in do_open
    encode_chunked=req.has_header('Transfer-encoding'))
  File "/auto/foo/python3-rhel6/lib/python3.6/http/client.py", line 1239, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/auto/foo/python3-rhel6/lib/python3.6/http/client.py", line 1285, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/auto/foo/python3-rhel6/lib/python3.6/http/client.py", line 1234, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/auto/foo/python3-rhel6/lib/python3.6/http/client.py", line 1026, in _send_output
    self.send(msg)
  File "/auto/foo/python3-rhel6/lib/python3.6/http/client.py", line 964, in send
    self.connect()
  File "/auto/foo/python3-rhel6/lib/python3.6/http/client.py", line 1400, in connect
    server_hostname=server_hostname)
  File "/auto/foo/python3-rhel6/lib/python3.6/ssl.py", line 407, in wrap_socket
    _context=self, _session=session)
  File "/auto/foo/python3-rhel6/lib/python3.6/ssl.py", line 814, in __init__
    self.do_handshake()
  File "/auto/foo/python3-rhel6/lib/python3.6/ssl.py", line 1068, in do_handshake
    self._sslobj.do_handshake()
  File "/auto/foo/python3-rhel6/lib/python3.6/ssl.py", line 689, in do_handshake
    self._sslobj.do_handshake()
ssl.SSLError: [SSL: SSLV3_ALERT_UNSUPPORTED_CERTIFICATE] sslv3 alert unsupported certificate (_ssl.c:833)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "./bar.py", line 375, in <module>
    start(args, overrides, threadlock)
  File "./bar.py", line 332, in start
    approved, alloc_message = Executor.approve(flow.the_portal.inst)
  File "/home/myuser/dev/bar/Executor.py", line 638, in approve
    with opener.open(request, json_request) as response:
  File "/auto/foo/python3-rhel6/lib/python3.6/urllib/request.py", line 526, in open
    response = self._open(req, data)
  File "/auto/foo/python3-rhel6/lib/python3.6/urllib/request.py", line 544, in _open
    '_open', req)
  File "/auto/foo/python3-rhel6/lib/python3.6/urllib/request.py", line 504, in _call_chain
    result = func(*args)
  File "/home/myuser/dev/bar/Auth.py", line 77, in https_open
    return self.do_open(self.getConnection, req)
  File "/auto/foo/python3-rhel6/lib/python3.6/urllib/request.py", line 1320, in do_open
    raise URLError(err)
urllib.error.URLError: <urlopen error [SSL: SSLV3_ALERT_UNSUPPORTED_CERTIFICATE] sslv3 alert unsupported certificate (_ssl.c:833)>

如果需要更多信息，请随时告诉我。任何帮助将不胜感激。

编辑： 这是证书（经过编辑的形式）：

Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            ...
    Signature Algorithm: sha256WithRSAEncryption
        Issuer: DC=com, DC=foo, CN=Foo Issuing CA - XXX
        Validity
            Not Before: ... 2018 GMT
            Not After : ... GMT
        Subject: O=Bar, OU=User, CN=myuser@foo.com
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                ...
        X509v3 extensions:
            X509v3 Key Usage:
                Key Encipherment, Data Encipherment
            X509v3 Subject Alternative Name:
                email:myuser@foo.com
            X509v3 Subject Key Identifier:
                ...
            X509v3 Authority Key Identifier:
                ...

            X509v3 CRL Distribution Points:

                Full Name:
                    ...
            Authority Information Access:
                CA Issuers - ...
                CA Issuers - ...

            X509v3 Extended Key Usage:
                TLS Web Server Authentication, TLS Web Client Authentication

用我的证书包验证这个文件说：

openssl verify -CAfile /.../certification_bundle.pem foo.cert
foo.cert: OK

我正在使用 OpenSSL v.1.0.1e-fips。这应该支持 TLSv1.2。

Answer 1

       X509v3 Key Usage:
            Key Encipherment, Data Encipherment

客户端证书由客户端签署一些质询和服务器验证签名来验证。为了签署此质询，证书必须具有 数字签名 的密钥用法。您的证书没有这使得它无法用于客户端身份验证。

另见Recommended key usage for a client certificate。

有趣的是，您的 CSR 可能包含适当的密钥用法，至少您尝试添加它：

keyUsage = nonRepudiation, digitalSignature, keyEncipherment

因此，CA 可能以错误的方式颁发证书，即与您请求的不同。

Answer 2

抱歉，我无法发表评论，但听起来您的证书签名请求缺少扩展密钥使用 (EKU) 扩展。您可能需要添加：

extendedKeyUsage = clientAuth

给你req_ext 部分。

然后重新生成 CSR 并使用 openssl req -in foo.csr -text 验证签名请求是否包含 EKU 扩展：

...
        X509v3 Extended Key Usage:
            TLS Web Client Authentication
...