include/ssl_key_handler.hpp

#pragma once

#include <openssl/bio.h>
#include <openssl/dh.h>
#include <openssl/dsa.h>
#include <openssl/dsa.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/rand.h>
#include <openssl/rsa.h>
#include <openssl/ssl.h>

#include <g3log/g3log.hpp>

namespace ensuressl {
static void init_openssl(void);
static void cleanup_openssl(void);
static EVP_PKEY *create_rsa_key(void);
static EVP_PKEY *create_ec_key(void);
static void handle_openssl_error(void);


inline bool verify_openssl_key_cert(const std::string &filepath) {
  bool private_key_valid = false;
  bool cert_valid = false;

  LOG(DEBUG) << "Checking certs in file " << filepath;

  FILE *file = fopen(filepath.c_str(), "r");
  if (file != NULL) {
    EVP_PKEY *pkey = PEM_read_PrivateKey(file, NULL, NULL, NULL);
    int rc;
    if (pkey) {
      int type = EVP_PKEY_type(pkey->type);
      switch (type) {
        case EVP_PKEY_RSA:
        case EVP_PKEY_RSA2: {
          LOG(DEBUG) << "Found an RSA key";
          RSA *rsa = EVP_PKEY_get1_RSA(pkey);
          if (rsa){
            if (RSA_check_key(rsa) == 1) {
              private_key_valid = true;
            } else {
              LOG(WARNING) << "Key not valid error number " << ERR_get_error();
            }
            RSA_free(rsa);
          }
          break;
        }
        case EVP_PKEY_EC:{
          LOG(DEBUG) << "Found an EC key";
          EC_KEY* ec = EVP_PKEY_get1_EC_KEY(pkey);
          if (ec){
            if (EC_KEY_check_key(ec) == 1) {
              //private_key_valid = true;
            } else {
              LOG(WARNING) << "Key not valid error number " << ERR_get_error();
            }
            EC_KEY_free(ec);
          }
          break;
        }
        default:
          LOG(WARNING) << "Found an unrecognized key type " << type;
          break;
      }

      if (private_key_valid) {
        X509 *x509 = PEM_read_X509(file, NULL, NULL, NULL);
        if (!x509){
          LOG(DEBUG) << "error getting x509 cert " << ERR_get_error();
        } else {
          rc = X509_verify(x509, pkey);
          if (rc == 1) {
            cert_valid = true;
          } else {
             LOG(WARNING) << "Error in verifying private key signature " << ERR_get_error();
          }
        }
      }

      EVP_PKEY_free(pkey);
    }
    fclose(file);
  }
  return cert_valid;
}

inline void generate_ssl_certificate(const std::string &filepath) {
  FILE *pFile = NULL;
  LOG(WARNING) << "Generating new keys";
  init_openssl();

  LOG(WARNING) << "Generating RSA key";
  EVP_PKEY *pRsaPrivKey = create_rsa_key();

  //LOG(WARNING) << "Generating EC key";
  //EVP_PKEY *pRsaPrivKey = create_ec_key();

  LOG(WARNING) << "Generating x509 Certificate";
  // Use this code to directly generate a certificate
  X509 *x509;
  x509 = X509_new();
  if (x509) {

    // Get a random number from the RNG for the certificate serial number
    // If this is not random, regenerating certs throws broswer errors
    std::random_device rd;
    int serial = rd();

    ASN1_INTEGER_set(X509_get_serialNumber(x509), serial);

    // not before this moment
    X509_gmtime_adj(X509_get_notBefore(x509), 0);
    // Cert is valid for 10 years
    X509_gmtime_adj(X509_get_notAfter(x509), 60L * 60L * 24L * 365L * 10L);

    // set the public key to the key we just generated
    X509_set_pubkey(x509, pRsaPrivKey);

    // Get the subject name
    X509_NAME *name;
    name = X509_get_subject_name(x509);

    X509_NAME_add_entry_by_txt(name, "C", MBSTRING_ASC, (unsigned char *)"US", -1, -1, 0);
    X509_NAME_add_entry_by_txt(name, "O", MBSTRING_ASC, (unsigned char *)"Intel BMC", -1, -1, 0);
    X509_NAME_add_entry_by_txt(name, "CN", MBSTRING_ASC, (unsigned char *)"testhost", -1, -1, 0);
    // set the CSR options
    X509_set_issuer_name(x509, name);

    // Sign the certificate with our private key
    X509_sign(x509, pRsaPrivKey, EVP_sha256());

    pFile = fopen(filepath.c_str(), "wt");

    if (pFile) {
      PEM_write_PrivateKey(pFile, pRsaPrivKey, NULL, NULL, 0, 0, NULL);
      
      PEM_write_X509(pFile, x509);
      fclose(pFile);
      pFile = NULL;
    }

    X509_free(x509);
  }

  if (pRsaPrivKey) {
    EVP_PKEY_free(pRsaPrivKey);
    pRsaPrivKey = NULL;
  }

  // cleanup_openssl();
}

EVP_PKEY *create_rsa_key(void) {
  RSA *pRSA = NULL;
  EVP_PKEY *pKey = NULL;
  pRSA = RSA_generate_key(2048, RSA_3, NULL, NULL);
  pKey = EVP_PKEY_new();
  if (pRSA && pKey && EVP_PKEY_assign_RSA(pKey, pRSA)) {
    /* pKey owns pRSA from now */
    if (RSA_check_key(pRSA) <= 0) {
      fprintf(stderr, "RSA_check_key failed.\n");
      handle_openssl_error();
      EVP_PKEY_free(pKey);
      pKey = NULL;
    }
  } else {
    handle_openssl_error();
    if (pRSA) {
      RSA_free(pRSA);
      pRSA = NULL;
    }
    if (pKey) {
      EVP_PKEY_free(pKey);
      pKey = NULL;
    }
  }
  return pKey;
}

EVP_PKEY *create_ec_key(void) {
  EC_KEY *myecc = NULL;
  EVP_PKEY *pKey = NULL;
  int eccgrp = 0;
  eccgrp = OBJ_txt2nid("prime256v1");

  // TODO handle errors
  myecc = EC_KEY_new_by_curve_name(eccgrp);
  EC_KEY_set_asn1_flag(myecc, OPENSSL_EC_NAMED_CURVE);
  EC_KEY_generate_key(myecc);
  pKey = EVP_PKEY_new();

  if (myecc && pKey && EVP_PKEY_assign_EC_KEY(pKey, myecc)) {
    /* pKey owns pRSA from now */
    if (EC_KEY_check_key(myecc) <= 0) {
      fprintf(stderr, "EC_check_key failed.\n");
      handle_openssl_error();
      EVP_PKEY_free(pKey);
      pKey = NULL;
    }
  } else {
    handle_openssl_error();
    if (myecc) {
      EC_KEY_free(myecc);
      myecc = NULL;
    }
    if (pKey) {
      EVP_PKEY_free(pKey);
      pKey = NULL;
    }
  }
  return pKey;
}

void init_openssl(void) {
  if (SSL_library_init()) {
    SSL_load_error_strings();
    OpenSSL_add_all_algorithms();
    RAND_load_file("/dev/urandom", 1024);
  } else
    exit(EXIT_FAILURE);
}

void cleanup_openssl(void) {
  CRYPTO_cleanup_all_ex_data();
  ERR_free_strings();
  ERR_remove_thread_state(0);
  EVP_cleanup();
}

void handle_openssl_error(void) { ERR_print_errors_fp(stderr); }
inline void ensure_openssl_key_present_and_valid(const std::string &filepath) {
  bool pem_file_valid = false;

  pem_file_valid = verify_openssl_key_cert(filepath);
  
  if (!pem_file_valid) {
    LOG(WARNING) << "Error in verifying signature, regenerating";
    generate_ssl_certificate(filepath);
  }
}
}