mariadb/plugin/auth_examples/dialog_examples.c
Sergei Golubchik 7c40996cc8 MDEV-12321 authentication plugin: SET PASSWORD support
Support SET PASSWORD for authentication plugins.

Authentication plugin API is extended with two optional methods:
* hash_password() is used to compute a password hash (or digest)
  from the plain-text password. This digest will be stored in mysql.user
  table
* preprocess_hash() is used to convert this digest into some memory
  representation that can be later used to authenticate a user.
  Build-in plugins convert the hash from hexadecimal or base64 to binary,
  to avoid doing it on every authentication attempt.

Note a change in behavior: when loading privileges (on startup or on
FLUSH PRIVILEGES) an account with an unknown plugin was loaded with a
warning (e.g. "Plugin 'foo' is not loaded"). But such an account could
not be used for authentication until the plugin is installed. Now an
account like that will not be loaded at all (with a warning, still).
Indeed, without plugin's preprocess_hash() method the server cannot know
how to load an account. Thus, if a new authentication plugin is
installed run-time, one might need FLUSH PRIVILEGES to activate all
existing accounts that were using this new plugin.
2018-10-31 16:06:16 +01:00

158 lines
4.1 KiB
C

/* Copyright (C) 2010 Sergei Golubchik and Monty Program Ab
Copyright (c) 2010, 2011, Oracle and/or its affiliates.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; version 2 of the
License.
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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
/**
@file
examples for dialog client authentication plugin
Two examples are provided: two_questions server plugin, that asks
the password and an "Are you sure?" question with a reply "yes, of course".
It demonstrates the usage of "password" (input is hidden) and "ordinary"
(input can be echoed) questions, and how to mark the last question,
to avoid an extra roundtrip.
And three_attempts plugin that gives the user three attempts to enter
a correct password. It shows the situation when a number of questions
is not known in advance.
*/
#include <mysql/plugin_auth.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <mysql/auth_dialog_client.h>
/********************* SERVER SIDE ****************************************/
/**
dialog demo with two questions, one password and one, the last, ordinary.
*/
static int two_questions(MYSQL_PLUGIN_VIO *vio, MYSQL_SERVER_AUTH_INFO *info)
{
unsigned char *pkt;
int pkt_len;
/* send a password question */
if (vio->write_packet(vio,
(const unsigned char *) PASSWORD_QUESTION "Password, please:",
18))
return CR_ERROR;
/* read the answer */
if ((pkt_len= vio->read_packet(vio, &pkt)) < 0)
return CR_ERROR;
info->password_used= PASSWORD_USED_YES;
/* fail if the password is wrong */
if (strcmp((const char *) pkt, info->auth_string))
return CR_ERROR;
/* send the last, ordinary, question */
if (vio->write_packet(vio,
(const unsigned char *) LAST_QUESTION "Are you sure ?",
15))
return CR_ERROR;
/* read the answer */
if ((pkt_len= vio->read_packet(vio, &pkt)) < 0)
return CR_ERROR;
/* check the reply */
return strcmp((const char *) pkt, "yes, of course") ? CR_ERROR : CR_OK;
}
static struct st_mysql_auth two_handler=
{
MYSQL_AUTHENTICATION_INTERFACE_VERSION,
"dialog", /* requires dialog client plugin */
two_questions,
NULL, NULL /* no PASSWORD() */
};
/* dialog demo where the number of questions is not known in advance */
static int three_attempts(MYSQL_PLUGIN_VIO *vio, MYSQL_SERVER_AUTH_INFO *info)
{
unsigned char *pkt;
int pkt_len, i;
for (i= 0; i < 3; i++)
{
/* send the prompt */
if (vio->write_packet(vio,
(const unsigned char *) PASSWORD_QUESTION "Password, please:", 18))
return CR_ERROR;
/* read the password */
if ((pkt_len= vio->read_packet(vio, &pkt)) < 0)
return CR_ERROR;
info->password_used= PASSWORD_USED_YES;
/*
finish, if the password is correct.
note, that we did not mark the prompt packet as "last"
*/
if (strcmp((const char *) pkt, info->auth_string) == 0)
return CR_OK;
}
return CR_ERROR;
}
static struct st_mysql_auth three_handler=
{
MYSQL_AUTHENTICATION_INTERFACE_VERSION,
"dialog", /* requires dialog client plugin */
three_attempts,
NULL, NULL /* no PASSWORD() */
};
mysql_declare_plugin(dialog)
{
MYSQL_AUTHENTICATION_PLUGIN,
&two_handler,
"two_questions",
"Sergei Golubchik",
"Dialog plugin demo 1",
PLUGIN_LICENSE_GPL,
NULL,
NULL,
0x0100,
NULL,
NULL,
NULL,
0,
},
{
MYSQL_AUTHENTICATION_PLUGIN,
&three_handler,
"three_attempts",
"Sergei Golubchik",
"Dialog plugin demo 2",
PLUGIN_LICENSE_GPL,
NULL,
NULL,
0x0100,
NULL,
NULL,
NULL,
0,
}
mysql_declare_plugin_end;