boost asio with ECDSA certificate issue

Question

I am implementing SSL server using boost::asio.

The context initialization is shown in below code

    boost::asio::ssl::context_base::method SSL_version =
            static_cast<boost::asio::ssl::context_base::method>(param_values[ID_PROTOCOL_VERSION].int32_value);

    // load certificate files
    boost::shared_ptr<boost::asio::ssl::context> context_ = boost::shared_ptr<boost::asio::ssl::context>(
            new boost::asio::ssl::context(SSL_version));     
    p_ctx = boost::static_pointer_cast<void>(context_);

    context_->set_options(boost::asio::ssl::context::default_workarounds);

    context_->use_certificate_chain_file(cert_chain_file);
    context_->use_certificate_file(cert_file, boost::asio::ssl::context::pem);
    context_->use_private_key_file(cert_file, boost::asio::ssl::context::pem);

    context_->set_verify_mode(boost::asio::ssl::verify_peer | boost::asio::ssl::verify_fail_if_no_peer_cert);
    context_->set_verify_callback(boost::bind(&verify_certificate_cb, _1, _2));

    if (param_values[ID_CIPHER_LIST].int32_value != 0)
    {
        std::string cipher_list = "";
        generate_cipher_list(param_values[ID_CIPHER_LIST].int32_value, cipher_list);
        MA5G_logger::log(PRIORITY_INFO, "Supported cipher list %s", cipher_list.c_str());
        SSL_CTX_set_cipher_list((reinterpret_cast<boost::asio::ssl::context*>(p_ctx.get()))->native_handle(),
                cipher_list.c_str());
    }

in the cipher_list, I am supporting below list

AES128-SHA:AES256-SHA:AES128-SHA256:AES256-SHA256:AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA

With ECDSA certificates if I use cipher_list given above then client can not connect to the server and gives error "No shared cipher". But if I do not give cipher_list then the client can successfully connect to the server. The same cipher list works fine with RSA certificates.

The same ECDSA certificates work fine if I use openssl s_server with -cipher option to provide supported cipher_list

Can anyone help with this issue?

What does `SSL_CTX_set_cipher_list` return when you try setting the cipher list? — rkyser, Oct 02 '13 at 14:48

score 2 · Accepted Answer · answered Oct 07 '13 at 08:00

2

No sorry buddy I found the answer after lot of research.

The problem is with the cipher list and not with the code / certificate.

The same certificate uses ECDHE-ECDSA-AES256-SHA cipher with openssl client-server while used ECDH-ECDSA-AES256-SHA cipher for boost asio SSL client-server.

Anyways thanks @rkyser for your help!

answered Oct 07 '13 at 08:00

Chirag Desai

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Why is it so? ECDHE and ECDH are different ciphers, aren't they? – Alexander Shishenko Feb 08 '16 at 03:40

score 1 · Answer 2 · answered Oct 04 '13 at 15:57

1

I found this buried in the FAQ of the openssl-1.0.1 source code:

Why can't I make an SSL connection to a server using a DSA certificate?

Typically you'll see a message saying there are no shared ciphers when the same setup works fine with an RSA certificate. There are two possible causes. The client may not support connections to DSA servers most web browsers (including Netscape and MSIE) only support connections to servers supporting RSA cipher suites. The other cause is that a set of DH parameters has not been supplied to the server. DH parameters can be created with the dhparam(1) command and loaded using the SSL_CTX_set_tmp_dh() for example: check the source to s_server in apps/s_server.c for an example.

So based on this, make sure you are setting your DH parameters using SSL_CTX_set_tmp_dh().

answered Oct 04 '13 at 15:57

rkyser

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DSA and ECDSA certificates are two different certificate types in OpenSSL. In fact, his code will probably work with both RSA and DSS (DSA). And he would use `SSL_CTX_set_tmp_ecdh`, not `SSL_CTX_set_tmp_dh`. Anyway, `s_client` should not suffer like MSIE or Netscape. – jww Mar 04 '14 at 15:11
Just wanted to chime in and say thanks for posting this info, both rkyser and @jww. The docs are so damn confusing, it had me confused and thinking I needed to use tmp_dh callback and not tmp_ecdh callback. Looking back it should have been obvious to me, since ecdh != dh. The funny thing is though, that all the countless google searches on my problem yielded nothing about tmp_ecdh, not even a hint. This comment was it, and it helped immensely. Thanks again, – Mar 16 '15 at 10:42

boost asio with ECDSA certificate issue

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