SSL client authentication returning Bad Certificate error

Question

I was trying to connect to my custom wrote ssl server written in CPP. It has got client authentication features. Its throwing error Bad certificate when watched through Wireshark. At the server side the error returned was

14560:error:140890B2:SSL routines:SSL3_GET_CLIENT_CERTIFICATE:no certificate returned:s3_srvr.c:2619:

I used the following code to force requesting client certificate

SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, NULL);
SSL_CTX_set_verify_depth(ctx, 1);

I could see client returning certificate in Wireshark.

Which function should be used to set the public key used for verifying the client certificate at the server side?

Answer 1

From the error messages it looks like your client does not present a certificate to server and you explicitely requested that a client needs to present one (in server code):

SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, NULL);

What you probably need is to tell your client code to use certificate (along with a private key):

SSL_CTX_use_certificate_chain_file(ctx, pcszCertPath);
SSL_CTX_use_PrivateKey_file(ctx, pcszPrivKeyPath,SSL_FILETYPE_PEM);

I hope that helps. Also make sure that your server uses the same certificate chain (that it trusts the same CA's). If this is a problem, let me know and I'll help you do that.