dialog.cc File Reference

dialog client authentication plugin with examples More...

#include "my_config.h"
#include <mysql.h>
#include <mysql/client_plugin.h>
#include <mysql/plugin_auth.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "my_compiler.h"
#include <dlfcn.h>

Macros
#define	_GNU_SOURCE   /* for RTLD_DEFAULT */
#define	ORDINARY_QUESTION   "\2"
	first byte of the question string is the question "type". More...
#define	LAST_QUESTION   "\3"
#define	PASSWORD_QUESTION   "\4"
#define	LAST_PASSWORD   "\5"

Typedefs
typedef char *(*	mysql_authentication_dialog_ask_t) (MYSQL *mysql, int type, const char *prompt, char *buf, int buf_len)
	type of the mysql_authentication_dialog_ask function More...

Functions
static int	two_questions (MYSQL_PLUGIN_VIO *vio, MYSQL_SERVER_AUTH_INFO *info)
	dialog demo with two questions, one password and one, the last, ordinary. More...
static int	generate_auth_string_hash (char *outbuf, unsigned int *buflen, const char *inbuf, unsigned int inbuflen)
static int	validate_auth_string_hash (char *const inbuf, unsigned int buflen)
static int	set_salt (const char *password, unsigned int password_len, unsigned char *salt, unsigned char *salt_len)
static int	three_attempts (MYSQL_PLUGIN_VIO *vio, MYSQL_SERVER_AUTH_INFO *info)
	mysql_declare_plugin (dialog)
static char *	builtin_ask (MYSQL *mysql, int type, const char *prompt, char *buf, int buf_len)
static int	perform_dialog (MYSQL_PLUGIN_VIO *vio, MYSQL *mysql)
	The main function of the dialog plugin. More...
static int	init_dialog (char *unused1, size_t unused2, int unused3, va_list unused4)
	initialization function of the dialog plugin More...
	mysql_declare_client_plugin (AUTHENTICATION) "dialog"

Variables
static struct st_mysql_auth	two_handler
static struct st_mysql_auth	three_handler
static mysql_authentication_dialog_ask_t	ask
	MYSQL_CLIENT_PLUGIN_AUTHOR_ORACLE
Dialog Client Authentication	Plugin
Dialog Client Authentication	GPL
Dialog Client Authentication	nullptr
Dialog Client Authentication	init_dialog
Dialog Client Authentication	perform_dialog
Dialog Client Authentication	mysql_end_client_plugin

Detailed Description

dialog client authentication plugin with examples

dialog is a general purpose client authentication plugin, it simply asks the user the question, as provided by the server and reports the answer back to the server. No encryption is involved, the answers are sent in clear text.

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.

Macro Definition Documentation

_GNU_SOURCE

#define _GNU_SOURCE   /* for RTLD_DEFAULT */

LAST_PASSWORD

#define LAST_PASSWORD   "\5"

LAST_QUESTION

#define LAST_QUESTION   "\3"

ORDINARY_QUESTION

#define ORDINARY_QUESTION   "\2"

first byte of the question string is the question "type".

It can be an "ordinary" or a "password" question. The last bit set marks a last question in the authentication exchange.

PASSWORD_QUESTION

#define PASSWORD_QUESTION   "\4"

Typedef Documentation

mysql_authentication_dialog_ask_t

typedef char *(* mysql_authentication_dialog_ask_t) (MYSQL *mysql, int type, const char *prompt, char *buf, int buf_len)

Initial value:

{
        MYSQL_AUTHENTICATION_PLUGIN,
        &three_handler,
        "three_attempts",
        "Sergei Golubchik",
        "Dialog plugin demo 2",
        PLUGIN_LICENSE_GPL,
        nullptr, 
        nullptr, 
        nullptr, 
        0x0101,
        nullptr,
        nullptr,
        nullptr,
        0,
    } mysql_declare_plugin_end

type of the mysql_authentication_dialog_ask function

Parameters

mysql	mysql
type	type of the input 1 - ordinary string input 2 - password string
prompt	prompt
buf	a buffer to store the use input
buf_len	the length of the buffer

Return values

a	pointer to the user input string. It may be equal to 'buf' or to 'mysql->password'. In all other cases it is assumed to be an allocated string, and the "dialog" plugin will free() it.

Function Documentation

builtin_ask()

static char * builtin_ask ( MYSQL *  mysql, int  type, const char *  prompt, char *  buf, int  buf_len  )

static

generate_auth_string_hash()

static int generate_auth_string_hash ( char *  outbuf, unsigned int *  buflen, const char *  inbuf, unsigned int  inbuflen  )

static

init_dialog()

static int init_dialog ( char *  unused1, size_t  unused2, int  unused3, va_list  unused4  )

static

initialization function of the dialog plugin

Pick up the client's authentication_dialog_ask() function, if exists, or fall back to the default implementation.

mysql_declare_client_plugin()

mysql_declare_client_plugin

(

AUTHENTICATION

)

mysql_declare_plugin()

mysql_declare_plugin

(

dialog

)

perform_dialog()

static int perform_dialog ( MYSQL_PLUGIN_VIO *  vio, MYSQL *  mysql  )

static

The main function of the dialog plugin.

Read the prompt, ask the question, send the reply, repeat until the server is satisfied.

Note

1. this plugin shows how a client authentication plugin may read a MySQL protocol OK packet internally - which is important where a number of packets is not known in advance.
2. the first byte of the prompt is special. it is not shown to the user, but signals whether it is the last question (prompt[0] & 1 == 1) or not last (prompt[0] & 1 == 0), and whether the input is a password (not echoed).
3. the prompt is expected to be sent zero-terminated

set_salt()

static int set_salt ( const char *  password, unsigned int  password_len, unsigned char *  salt, unsigned char *  salt_len  )

static

three_attempts()

static int three_attempts ( MYSQL_PLUGIN_VIO *  vio, MYSQL_SERVER_AUTH_INFO *  info  )

static

two_questions()

static int two_questions ( MYSQL_PLUGIN_VIO *  vio, MYSQL_SERVER_AUTH_INFO *  info  )

static

dialog demo with two questions, one password and one, the last, ordinary.

validate_auth_string_hash()

static int validate_auth_string_hash ( char *const  inbuf, unsigned int  buflen  )

static

Variable Documentation

ask

mysql_authentication_dialog_ask_t ask

static

GPL

Dialog Client Authentication GPL

init_dialog

Dialog Client Authentication init_dialog

MYSQL_CLIENT_PLUGIN_AUTHOR_ORACLE

MYSQL_CLIENT_PLUGIN_AUTHOR_ORACLE

mysql_end_client_plugin

Dialog Client Authentication mysql_end_client_plugin

nullptr

Dialog Client Authentication nullptr

perform_dialog

Dialog Client Authentication perform_dialog

Plugin

Dialog Client Authentication Plugin

three_handler

struct st_mysql_auth three_handler

static

Initial value:

= {
    MYSQL_AUTHENTICATION_INTERFACE_VERSION,
    "dialog", 
    three_attempts,
    generate_auth_string_hash,
    validate_auth_string_hash,
    set_salt,
    AUTH_FLAG_PRIVILEGED_USER_FOR_PASSWORD_CHANGE,
    nullptr}

two_handler

struct st_mysql_auth two_handler

static

Initial value:

= {
    MYSQL_AUTHENTICATION_INTERFACE_VERSION,
    "dialog", 
    two_questions,
    generate_auth_string_hash,
    validate_auth_string_hash,
    set_salt,
    AUTH_FLAG_PRIVILEGED_USER_FOR_PASSWORD_CHANGE,
    nullptr}