Creating a CSR using OpenSSL v1.1.1

[Joe Eremita <joe@xxxxxxxxxxxxxxxxxxxxx>]

Hello all,

    I am developing a library that uses an HSM, and I need to create a CSR to send to the CA. I have some examples using the X509_REQ to set the public key and attributes. I 've also seen examples of signing the CSR, which finds the req_info that is needed to sign the CSR: 

  EVP_PKEY_assign_RSA( pkey , rsa );
  X509_REQ_set_pubkey(req, pkey);

  subj=X509_REQ_get_subject_name(req);
  X509_NAME_add_entry_by_txt(subj,"C",
                          MBSTRING_ASC, (unsigned char *)"SK", -1, -1, 0);
  X509_NAME_add_entry_by_txt(subj,"CN",
                          MBSTRING_ASC, (unsigned char *)"Test", -1, -1, 0);

  int datasig_len;
  unsigned char *tobesigned;
  datasig_len = i2d_X509_REQ_INFO( req->req_info, NULL );

When I compile the last line, I get the error: error: 'invalid use of incomplete type ‘X509_REQ {aka struct X509_req_st}'

I have discovered that the header x509.h obfuscates the type 'req_info', and upon further research, I also found that this type was eliminated since v1.1.0 of OpenSSL.

Does anyone know of an alternative to accessing the 'req_info' element, or another way I can access the info I need to sign?

Thanks for your help.