我通过自签名证书（用我自己的CA）生成，现在我正试图让一个boost ASIO客户端验证服务器的身份。我用openssl验证了这些，验证似乎有效。
服务器和客户端代码分别为here和here。
我只修改了以下部分：

class server
{
public:
  server(boost::asio::io_service& io_service, unsigned short port)
    : io_service_(io_service),
      acceptor_(io_service,
          boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), port)),
      context_(boost::asio::ssl::context::tlsv12_server)
  {
    context_.set_options(
        boost::asio::ssl::context::default_workarounds
        | boost::asio::ssl::context::no_sslv2
        | boost::asio::ssl::context::single_dh_use);
    context_.set_password_callback(boost::bind(&server::get_password, this));
    // Use the certificate for my website that I had generated        context_.use_certificate_file("/home/paul/ca/intermediate/certs/mywebsite.net.cert.pem", boost::asio::ssl::context::pem);
    // Not sure if I need this, probably not. I do have an intermediate CA though        
    //context_.use_certificate_chain_file("/home/paul/ca/intermediate/certs/ca-chain.cert.pem");
    // Use website private key        context_.use_private_key_file("/home/paul/ca/intermediate/private/mywebsite.net.key.pem", boost::asio::ssl::context::pem);
    context_.use_tmp_dh_file("/home/paul/SSLTest/dh512.pem");
    start_accept();
  }

在客户端：

bool verify_certificate(bool preverified,
      boost::asio::ssl::verify_context& ctx)
  {
    // The verify callback can be used to check whether the certificate that is
    // being presented is valid for the peer. For example, RFC 2818 describes
    // the steps involved in doing this for HTTPS. Consult the OpenSSL
    // documentation for more details. Note that the callback is called once
    // for each certificate in the certificate chain, starting from the root
    // certificate authority.
    // In this example we will simply print the certificate's subject name.
    char subject_name[256];
    X509* cert = X509_STORE_CTX_get_current_cert(ctx.native_handle());
    X509_NAME_oneline(X509_get_subject_name(cert), subject_name, 256);
    std::cout << "Verifying " << subject_name << "\n";
    std::cout << "preverified: " << std::boolalpha << preverified << "\n";
    return preverified; 
  }
...
int main(int argc, char* argv[])
{
  try
  {
    boost::asio::io_service io_service;
    boost::asio::ip::tcp::resolver resolver(io_service);
    boost::asio::ip::tcp::resolver::query query("localhost", "3232");
    boost::asio::ip::tcp::resolver::iterator iterator = resolver.resolve(query);
    boost::asio::ssl::context ctx(boost::asio::ssl::context::tlsv12_client);
    std::ifstream ca_file("/home/paul/ca/certs/ca.cert.pem", std::ios::binary | std::ios::ate);
    std::vector<char> data;
    auto size = ca_file.tellg();
    data.resize(size);
    ca_file.seekg(0, std::ios::beg);
    ca_file.read(data.data(), size);
    ca_file.close();
    // Have my own CA added to the list of known CAs
    ctx.add_certificate_authority(boost::asio::buffer(data, data.size()));
    // Not sure if I need something here, the CA should be enough to
    // validate the server's certificate prompted (even if signed by the
    // intermediate CA)
    //ctx.load_verify_file("/home/paul/ca/private/ca.key.pem");
    //ctx.load_verify_file("/home/paul/ca/intermediate/private/intermediate.key.pem");
    client c(io_service, ctx, iterator);

然而，这是行不通的，客户端返回

Verifying /C=IT/ST=Italy/L=Milan/O=MyCompanyLtd/OU=MyCompanyLtd Auth/CN=mywebsite.net/[email protected]
preverified: false
Handshake failed: certificate verify failed

我知道回调中没有执行验证，但我认为set_verification_callback中设置的回调将在预验证后调用（因此使用preverified参数）。
我哪里错了？