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/*
Minetest
Copyright (C) 2015, 2016 est31 <MTest31@outlook.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <algorithm>
#include <string>
#include "auth.h"
#include "base64.h"
#include "sha1.h"
#include "srp.h"
#include "util/string.h"
#include "debug.h"
// Get an sha-1 hash of the player's name combined with
// the password entered. That's what the server uses as
// their password. (Exception : if the password field is
// blank, we send a blank password - this is for backwards
// compatibility with password-less players).
std::string translate_password(const std::string &name,
const std::string &password)
{
if (password.length() == 0)
return "";
std::string slt = name + password;
SHA1 sha1;
sha1.addBytes(slt.c_str(), slt.length());
unsigned char *digest = sha1.getDigest();
std::string pwd = base64_encode(digest, 20);
free(digest);
return pwd;
}
// Call lower level SRP code to generate a verifier with the
// given pointers. Contains the preparations, call parameters
// and error checking common to all srp verifier generation code.
// See docs of srp_create_salted_verification_key for more info.
static inline void gen_srp_v(const std::string &name,
const std::string &password, char **salt, size_t *salt_len,
char **bytes_v, size_t *len_v)
{
std::string n_name = lowercase(name);
SRP_Result res = srp_create_salted_verification_key(SRP_SHA256, SRP_NG_2048,
n_name.c_str(), (const unsigned char *)password.c_str(),
password.size(), (unsigned char **)salt, salt_len,
(unsigned char **)bytes_v, len_v, NULL, NULL);
FATAL_ERROR_IF(res != SRP_OK, "Couldn't create salted SRP verifier");
}
/// Creates a verification key with given salt and password.
std::string generate_srp_verifier(const std::string &name,
const std::string &password, const std::string &salt)
{
size_t salt_len = salt.size();
// The API promises us that the salt doesn't
// get modified if &salt_ptr isn't NULL.
char *salt_ptr = (char *)salt.c_str();
char *bytes_v = nullptr;
size_t verifier_len = 0;
gen_srp_v(name, password, &salt_ptr, &salt_len, &bytes_v, &verifier_len);
std::string verifier = std::string(bytes_v, verifier_len);
free(bytes_v);
return verifier;
}
/// Creates a verification key and salt with given password.
void generate_srp_verifier_and_salt(const std::string &name,
const std::string &password, std::string *verifier,
std::string *salt)
{
char *bytes_v = nullptr;
size_t verifier_len;
char *salt_ptr = nullptr;
size_t salt_len;
gen_srp_v(name, password, &salt_ptr, &salt_len, &bytes_v, &verifier_len);
*verifier = std::string(bytes_v, verifier_len);
*salt = std::string(salt_ptr, salt_len);
free(bytes_v);
free(salt_ptr);
}
/// Gets an SRP verifier, generating a salt,
/// and encodes it as DB-ready string.
std::string get_encoded_srp_verifier(const std::string &name,
const std::string &password)
{
std::string verifier;
std::string salt;
generate_srp_verifier_and_salt(name, password, &verifier, &salt);
return encode_srp_verifier(verifier, salt);
}
/// Converts the passed SRP verifier into a DB-ready format.
std::string encode_srp_verifier(const std::string &verifier,
const std::string &salt)
{
std::ostringstream ret_str;
ret_str << "#1#"
<< base64_encode((unsigned char *)salt.c_str(), salt.size()) << "#"
<< base64_encode((unsigned char *)verifier.c_str(), verifier.size());
return ret_str.str();
}
/// Reads the DB-formatted SRP verifier and gets the verifier
/// and salt components.
bool decode_srp_verifier_and_salt(const std::string &encoded,
std::string *verifier, std::string *salt)
{
std::vector<std::string> components = str_split(encoded, '#');
if ((components.size() != 4)
|| (components[1] != "1") // 1 means srp
|| !base64_is_valid(components[2])
|| !base64_is_valid(components[3]))
return false;
*salt = base64_decode(components[2]);
*verifier = base64_decode(components[3]);
return true;
}
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