nntpchan/contrib/backends/nntpchan-daemon/tools/authtool.cpp

#include "base64.hpp"
#include "crypto.hpp"

#include <cassert>
#include <cstring>
#include <string>
#include <iostream>
#include <sodium.h>

static void print_help(const std::string & exename)
{
  std::cout << "usage: " << exename << " [help|gen|check]" << std::endl;
}

static void print_long_help()
{

}

static void gen_passwd(const std::string & username, const std::string & passwd)
{
  std::array<uint8_t, 8> random;
  randombytes_buf(random.data(), random.size());
  std::string salt = nntpchan::B64Encode(random.data(), random.size());
  std::string cred = passwd + salt;
  nntpchan::SHA512Digest d;
  nntpchan::SHA512((const uint8_t *)cred.c_str(), cred.size(), d);
  std::string hash = nntpchan::B64Encode(d.data(), d.size());
  std::cout << username << ":" << hash << ":" << salt << std::endl;
}


static bool check_cred(const std::string & cred, const std::string & passwd)
{
  auto idx = cred.find(":");
  if(idx == std::string::npos || idx == 0) return false;
  std::string part = cred.substr(idx+1);
  idx = part.find(":");
  if(idx == std::string::npos || idx == 0) return false;
  std::string salt = part.substr(idx+1);
  std::string hash = part.substr(0, idx);
  std::vector<uint8_t> h;
  if(!nntpchan::B64Decode(hash, h)) return false;
  nntpchan::SHA512Digest d;
  std::string l = passwd + salt;
  nntpchan::SHA512((const uint8_t*)l.data(), l.size(), d);
  return std::memcmp(h.data(), d.data(), d.size()) == 0;
}

int main(int argc, char * argv[])
{
  assert(sodium_init() == 0);
  if(argc == 1) {
    print_help(argv[0]);
    return 1;
  }
  std::string cmd(argv[1]);
  if (cmd == "help") {
    print_long_help();
    return 0;
  }
  if (cmd == "gen") {
    if(argc == 4) {
      gen_passwd(argv[2], argv[3]);
      return 0;
    } else {
      std::cout << "usage: " << argv[0] << " gen username password" << std::endl;
      return 1;
    }
  }
  if(cmd == "check" ) {
    std::string cred;
    std::cout << "credential: " ;
    if(!std::getline(std::cin, cred)) {
      return 1;
    }
    std::string passwd;
    std::cout << "password: ";
    if(!std::getline(std::cin, passwd)) {
      return 1;
    }
    if(check_cred(cred, passwd)) {
      std::cout << "okay" << std::endl;
      return 0;
    }
    std::cout << "bad login" << std::endl;
    return 1;
  }

  print_help(argv[0]);
  return 1;
}