Much better API for auth.{cpp, h}

* No function overloading
* Adhere coding style and with method names following
  lowercase_underscore_style
* Use std::string in external API, handling these is
  much more fun

src/client.cpp

@@ -399,7 +399,7 @@ void Client::step(float dtime)
 			memset(pName, 0, PLAYERNAME_SIZE * sizeof(char));
 			memset(pPassword, 0, PASSWORD_SIZE * sizeof(char));
 
-			std::string hashed_password = translatePassword(myplayer->getName(), m_password);
+			std::string hashed_password = translate_password(myplayer->getName(), m_password);
 			snprintf(pName, PLAYERNAME_SIZE, "%s", myplayer->getName());
 			snprintf(pPassword, PASSWORD_SIZE, "%s", hashed_password.c_str());
 
@@ -1031,18 +1031,14 @@ void Client::startAuth(AuthMechanism chosen_auth_mechanism)
 	switch (chosen_auth_mechanism) {
 		case AUTH_MECHANISM_FIRST_SRP: {
 			// send srp verifier to server
+			std::string verifier;
+			std::string salt;
+			generate_srp_verifier_and_salt(getPlayerName(), m_password,
+				&verifier, &salt);
+
 			NetworkPacket resp_pkt(TOSERVER_FIRST_SRP, 0);
-			char *salt, *bytes_v;
-			std::size_t len_salt, len_v;
-			salt = NULL;
-			getSRPVerifier(getPlayerName(), m_password,
-				&salt, &len_salt, &bytes_v, &len_v);
-			resp_pkt
-				<< std::string((char*)salt, len_salt)
-				<< std::string((char*)bytes_v, len_v)
-				<< (u8)((m_password == "") ? 1 : 0);
-			free(salt);
-			free(bytes_v);
+			resp_pkt << salt << verifier << (u8)((m_password == "") ? 1 : 0);
+
 			Send(&resp_pkt);
 			break;
 		}
@@ -1051,7 +1047,7 @@ void Client::startAuth(AuthMechanism chosen_auth_mechanism)
 			u8 based_on = 1;
 
 			if (chosen_auth_mechanism == AUTH_MECHANISM_LEGACY_PASSWORD) {
-				m_password = translatePassword(getPlayerName(), m_password);
+				m_password = translate_password(getPlayerName(), m_password);
 				based_on = 0;
 			}
 
@@ -1197,8 +1193,8 @@ void Client::sendChangePassword(const std::string &oldpassword,
 		m_new_password = newpassword;
 		startAuth(choseAuthMech(m_sudo_auth_methods));
 	} else {
-		std::string oldpwd = translatePassword(playername, oldpassword);
-		std::string newpwd = translatePassword(playername, newpassword);
+		std::string oldpwd = translate_password(playername, oldpassword);
+		std::string newpwd = translate_password(playername, newpassword);
 
 		NetworkPacket pkt(TOSERVER_PASSWORD_LEGACY, 2 * PASSWORD_SIZE);
 

src/network/serverpackethandler.cpp

@@ -261,9 +261,9 @@ void Server::handleCommand_Init(NetworkPacket* pkt)
 			auth_mechs |= AUTH_MECHANISM_FIRST_SRP;
 		} else {
 			// Take care of default passwords.
-			client->enc_pwd = getSRPVerifier(playerName, default_password);
+			client->enc_pwd = get_encoded_srp_verifier(playerName, default_password);
 			auth_mechs |= AUTH_MECHANISM_SRP;
-			// Create auth, but only on successful login
+			// Allocate player in db, but only on successful login.
 			client->create_player_on_auth_success = true;
 		}
 	}
@@ -549,7 +549,7 @@ void Server::handleCommand_Init_Legacy(NetworkPacket* pkt)
 		std::string raw_default_password =
 			g_settings->get("default_password");
 		std::string initial_password =
-			translatePassword(playername, raw_default_password);
+			translate_password(playername, raw_default_password);
 
 		// If default_password is empty, allow any initial password
 		if (raw_default_password.length() == 0)
@@ -1831,7 +1831,7 @@ void Server::handleCommand_FirstSrp(NetworkPacket* pkt)
 
 		std::string initial_ver_key;
 
-		initial_ver_key = encodeSRPVerifier(verification_key, salt);
+		initial_ver_key = encode_srp_verifier(verification_key, salt);
 		m_script->createAuth(playername, initial_ver_key);
 
 		acceptAuth(pkt->getPeerId(), false);
@@ -1843,7 +1843,7 @@ void Server::handleCommand_FirstSrp(NetworkPacket* pkt)
 			return;
 		}
 		m_clients.event(pkt->getPeerId(), CSE_SudoLeave);
-		std::string pw_db_field = encodeSRPVerifier(verification_key, salt);
+		std::string pw_db_field = encode_srp_verifier(verification_key, salt);
 		bool success = m_script->setPassword(playername, pw_db_field);
 		if (success) {
 			actionstream << playername << " changes password" << std::endl;
@@ -1917,22 +1917,14 @@ void Server::handleCommand_SrpBytesA(NetworkPacket* pkt)
 
 	client->chosen_mech = chosen;
 
-	std::string bytes_s;
-	std::string bytes_v;
+	std::string salt;
+	std::string verifier;
 
 	if (based_on == 0) {
-		char *p_bytes_s = 0;
-		size_t len_s = 0;
-		char *p_bytes_v = 0;
-		size_t len_v = 0;
-		getSRPVerifier(client->getName(), client->enc_pwd,
-			&p_bytes_s, &len_s,
-			&p_bytes_v, &len_v);
-		bytes_s = std::string(p_bytes_s, len_s);
-		bytes_v = std::string(p_bytes_v, len_v);
-		free(p_bytes_s);
-		free(p_bytes_v);
-	} else if (!decodeSRPVerifier(client->enc_pwd, &bytes_s, &bytes_v)) {
+
+		generate_srp_verifier_and_salt(client->getName(), client->enc_pwd,
+			&verifier, &salt);
+	} else if (!decode_srp_verifier_and_salt(client->enc_pwd, &verifier, &salt)) {
 		// Non-base64 errors should have been catched in the init handler
 		actionstream << "Server: User " << client->getName()
 			<< " tried to log in, but srp verifier field"
@@ -1946,8 +1938,8 @@ void Server::handleCommand_SrpBytesA(NetworkPacket* pkt)
 
 	client->auth_data = srp_verifier_new(SRP_SHA256, SRP_NG_2048,
 		client->getName().c_str(),
-		(const unsigned char *) bytes_s.c_str(), bytes_s.size(),
-		(const unsigned char *) bytes_v.c_str(), bytes_v.size(),
+		(const unsigned char *) salt.c_str(), salt.size(),
+		(const unsigned char *) verifier.c_str(), verifier.size(),
 		(const unsigned char *) bytes_A.c_str(), bytes_A.size(),
 		NULL, 0,
 		(unsigned char **) &bytes_B, &len_B, NULL, NULL);
@@ -1966,7 +1958,7 @@ void Server::handleCommand_SrpBytesA(NetworkPacket* pkt)
 	}
 
 	NetworkPacket resp_pkt(TOCLIENT_SRP_BYTES_S_B, 0, pkt->getPeerId());
-	resp_pkt << bytes_s << std::string(bytes_B, len_B);
+	resp_pkt << salt << std::string(bytes_B, len_B);
 	Send(&resp_pkt);
 }
 

src/script/lua_api/l_util.cpp

@@ -251,7 +251,7 @@ int ModApiUtil::l_get_password_hash(lua_State *L)
 	NO_MAP_LOCK_REQUIRED;
 	std::string name = luaL_checkstring(L, 1);
 	std::string raw_password = luaL_checkstring(L, 2);
-	std::string hash = translatePassword(name, raw_password);
+	std::string hash = translate_password(name, raw_password);
 	lua_pushstring(L, hash.c_str());
 	return 1;
 }

src/util/auth.cpp

@@ -1,6 +1,6 @@
 /*
 Minetest
-Copyright (C) 2015 est31 <MTest31@outlook.com>
+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
@@ -31,7 +31,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 // 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 translatePassword(const std::string &name,
+std::string translate_password(const std::string &name,
 	const std::string &password)
 {
 	if (password.length() == 0)
@@ -46,7 +46,11 @@ std::string translatePassword(const std::string &name,
 	return pwd;
 }
 
-void getSRPVerifier(const std::string &name,
+// 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)
 {
@@ -58,72 +62,76 @@ void getSRPVerifier(const std::string &name,
 	FATAL_ERROR_IF(res != SRP_OK, "Couldn't create salted SRP verifier");
 }
 
-// Get a db-ready SRP verifier
-// If the salt param is NULL, one is automatically generated.
-// Please free() it afterwards. You shouldn't use it for other purposes,
-// as you will need the contents of salt_len too.
-inline static std::string getSRPVerifier(const std::string &name,
-	const std::string &password, char ** salt, size_t salt_len)
-{
-	char * bytes_v = NULL;
-	size_t len_v;
-	getSRPVerifier(name, password, salt, &salt_len,
-		&bytes_v, &len_v);
-	assert(*salt); // usually, srp_create_salted_verification_key promises us to return SRP_ERR when *salt == NULL
-	std::string ret_val = encodeSRPVerifier(std::string(bytes_v, len_v),
-		std::string(*salt, salt_len));
-	free(bytes_v);
-	return ret_val;
-}
-
-// Get a db-ready SRP verifier
-std::string getSRPVerifier(const std::string &name,
-	const std::string &password)
-{
-	char * salt = NULL;
-	std::string ret_val = getSRPVerifier(name,
-		password, &salt, 0);
-	free(salt);
-	return ret_val;
-}
-
-// Get a db-ready SRP verifier
-std::string getSRPVerifier(const std::string &name,
+/// 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)
 {
-	// The implementation won't change the salt if its set,
-	// therefore we can cast.
-	char *salt_cstr = (char *)salt.c_str();
-	return getSRPVerifier(name, password,
-		&salt_cstr, salt.size());
+	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 = NULL;
+	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;
 }
 
-// Make a SRP verifier db-ready
-std::string encodeSRPVerifier(const std::string &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 = NULL;
+	size_t verifier_len;
+	char *salt_ptr = NULL;
+	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());
+		<< base64_encode((unsigned char *)salt.c_str(), salt.size()) << "#"
+		<< base64_encode((unsigned char *)verifier.c_str(), verifier.size());
 	return ret_str.str();
 }
 
-bool decodeSRPVerifier(const std::string &enc_pwd,
-	std::string *salt, std::string *bytes_v)
+/// 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> pwd_components = str_split(enc_pwd, '#');
+	std::vector<std::string> components = str_split(encoded, '#');
 
-	if ((pwd_components.size() != 4)
-			|| (pwd_components[1] != "1") // 1 means srp
-			|| !base64_is_valid(pwd_components[2])
-			|| !base64_is_valid(pwd_components[3]))
+	if ((components.size() != 4)
+			|| (components[1] != "1") // 1 means srp
+			|| !base64_is_valid(components[2])
+			|| !base64_is_valid(components[3]))
 		return false;
 
-	std::string salt_str = base64_decode(pwd_components[2]);
-	std::string bytes_v_str = base64_decode(pwd_components[3]);
-	*salt = salt_str;
-	*bytes_v = bytes_v_str;
+	*salt = base64_decode(components[2]);
+	*verifier = base64_decode(components[3]);
 	return true;
 
 }

src/util/auth.h

@@ -1,6 +1,6 @@
 /*
 Minetest
-Copyright (C) 2015 est31 <MTest31@outlook.com>
+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
@@ -20,18 +20,31 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #ifndef AUTH_H
 #define AUTH_H
 
-std::string translatePassword(const std::string &name,
+/// Gets the base64 encoded legacy password db entry.
+std::string translate_password(const std::string &name,
 	const std::string &password);
-void getSRPVerifier(const std::string &name,
-	const std::string &password, char **salt, size_t *salt_len,
-	char **bytes_v, size_t *len_v);
-std::string getSRPVerifier(const std::string &name,
-	const std::string &password);
-std::string getSRPVerifier(const std::string &name,
+
+/// 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);
-std::string encodeSRPVerifier(const std::string &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);
+
+/// 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);
+
+/// Converts the passed SRP verifier into a DB-ready format.
+std::string encode_srp_verifier(const std::string &verifier,
 	const std::string &salt);
-bool decodeSRPVerifier(const std::string &enc_pwd,
+
+/// 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 *salt, std::string *bytes_v);
 
-#endif
+#endif