358 lines
9.7 KiB
C++
358 lines
9.7 KiB
C++
/*
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* Copyright (c) 2016 MariaDB Corporation Ab
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*
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* Use of this software is governed by the Business Source License included
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* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
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*
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* Change Date: 2025-10-29
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*
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* On the date above, in accordance with the Business Source License, use
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* of this software will be governed by version 2 or later of the General
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* Public License.
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*/
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#define MXS_MODULE_NAME "telnetd"
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#include <maxscale/ccdefs.hh>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <maxbase/alloc.h>
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#include <maxscale/dcb.hh>
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#include <maxscale/buffer.hh>
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#include <maxscale/service.hh>
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#include <maxscale/session.hh>
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#include <maxscale/protocol.hh>
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#include <sys/ioctl.h>
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#include <errno.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <maxscale/router.hh>
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#include <maxscale/poll.hh>
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#include <maxbase/atomic.h>
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#include <telnetd.hh>
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#include <maxscale/adminusers.h>
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#include <maxscale/modinfo.h>
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/**
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* @file telnetd.c - telnet daemon protocol module
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*
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* The telnetd protocol module is intended as a mechanism to allow connections
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* into the gateway for the purpsoe of accessing debugging information within
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* the gateway rather than a protocol to be used to send queries to backend
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* databases.
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*
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* In the first instance it is intended to allow a debug connection to access
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* internal data structures, however it may also be used to manage the
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* configuration of the gateway.
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*
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* @verbatim
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* Revision History
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* Date Who Description
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* 17/06/2013 Mark Riddoch Initial version
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* 17/07/2013 Mark Riddoch Addition of login phase
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* 07/07/2015 Martin Brampton Call unified dcb_close on error
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*
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* @endverbatim
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*/
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static int telnetd_read_event(DCB* dcb);
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static int telnetd_write_event(DCB* dcb);
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static int telnetd_write(DCB* dcb, GWBUF* queue);
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static int telnetd_error(DCB* dcb);
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static int telnetd_hangup(DCB* dcb);
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static int telnetd_accept(DCB*);
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static int telnetd_close(DCB* dcb);
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static char* telnetd_default_auth();
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/**
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* The "module object" for the telnetd protocol module.
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*/
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static void telnetd_command(DCB*, unsigned char* cmd);
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static void telnetd_echo(DCB* dcb, int enable);
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extern "C"
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{
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/**
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* The module entry point routine. It is this routine that
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* must populate the structure that is referred to as the
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* "module object", this is a structure with the set of
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* external entry points for this module.
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*
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* @return The module object
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*/
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MXS_MODULE* MXS_CREATE_MODULE()
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{
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MXS_INFO("Initialise Telnetd Protocol module.");
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static MXS_PROTOCOL MyObject =
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{
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telnetd_read_event, /**< Read - EPOLLIN handler */
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telnetd_write, /**< Write - data from gateway */
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telnetd_write_event, /**< WriteReady - EPOLLOUT handler */
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telnetd_error, /**< Error - EPOLLERR handler */
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telnetd_hangup, /**< HangUp - EPOLLHUP handler */
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telnetd_accept, /**< Accept */
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NULL, /**< Connect */
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telnetd_close, /**< Close */
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NULL, /**< Authentication */
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telnetd_default_auth, /**< Default authenticator */
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NULL, /**< Connection limit reached */
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NULL,
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NULL,
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};
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static MXS_MODULE info =
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{
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MXS_MODULE_API_PROTOCOL,
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MXS_MODULE_GA,
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MXS_PROTOCOL_VERSION,
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"A telnet deamon protocol for simple administration interface",
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"V1.1.1",
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MXS_NO_MODULE_CAPABILITIES,
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&MyObject,
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NULL, /* Process init. */
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NULL, /* Process finish. */
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NULL, /* Thread init. */
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NULL, /* Thread finish. */
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{
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{MXS_END_MODULE_PARAMS}
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}
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};
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return &info;
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}
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}
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/*lint +e14 */
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/**
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* The default authenticator name for this protocol
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*
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* @return name of authenticator
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*/
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static char* telnetd_default_auth()
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{
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return const_cast<char*>("NullAuthAllow");
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}
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/**
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* Read event for EPOLLIN on the telnetd protocol module.
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*
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* @param dcb The descriptor control block
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* @return
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*/
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static int telnetd_read_event(DCB* dcb)
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{
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int n;
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GWBUF* head = NULL;
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MXS_SESSION* session = dcb->session;
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TELNETD* telnetd = (TELNETD*)dcb->protocol;
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char* password, * t;
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if ((n = dcb_read(dcb, &head, 0)) != -1)
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{
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if (head)
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{
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unsigned char* ptr = GWBUF_DATA(head);
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ptr = GWBUF_DATA(head);
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while (GWBUF_LENGTH(head) && *ptr == TELNET_IAC)
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{
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telnetd_command(dcb, ptr + 1);
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GWBUF_CONSUME(head, 3);
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ptr = GWBUF_DATA(head);
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}
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if (GWBUF_LENGTH(head))
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{
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switch (telnetd->state)
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{
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case TELNETD_STATE_LOGIN:
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telnetd->username = strndup((char*)GWBUF_DATA(head), GWBUF_LENGTH(head));
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/* Strip the cr/lf from the username */
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t = strstr(telnetd->username, "\r\n");
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if (t)
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{
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*t = 0;
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}
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telnetd->state = TELNETD_STATE_PASSWD;
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dcb_printf(dcb, "Password: ");
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telnetd_echo(dcb, 0);
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gwbuf_consume(head, GWBUF_LENGTH(head));
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break;
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case TELNETD_STATE_PASSWD:
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password = strndup((char*)GWBUF_DATA(head), GWBUF_LENGTH(head));
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/* Strip the cr/lf from the username */
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t = strstr(password, "\r\n");
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if (t)
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{
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*t = 0;
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}
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if (admin_verify_inet_user(telnetd->username, password))
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{
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telnetd_echo(dcb, 1);
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telnetd->state = TELNETD_STATE_DATA;
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dcb_printf(dcb, "\n\nMaxScale> ");
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}
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else
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{
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dcb_printf(dcb, "\n\rLogin incorrect\n\rLogin: ");
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telnetd_echo(dcb, 1);
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telnetd->state = TELNETD_STATE_LOGIN;
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MXS_FREE(telnetd->username);
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}
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gwbuf_consume(head, GWBUF_LENGTH(head));
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MXS_FREE(password);
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break;
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case TELNETD_STATE_DATA:
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MXS_SESSION_ROUTE_QUERY(session, head);
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break;
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}
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}
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else
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{
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// Force the free of the buffer header
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gwbuf_consume(head, 0);
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}
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}
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}
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return n;
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}
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/**
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* EPOLLOUT handler for the telnetd protocol module.
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*
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* @param dcb The descriptor control block
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* @return
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*/
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static int telnetd_write_event(DCB* dcb)
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{
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return dcb_drain_writeq(dcb);
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}
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/**
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* Write routine for the telnetd protocol module.
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*
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* Writes the content of the buffer queue to the socket
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* observing the non-blocking principles of the gateway.
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*
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* @param dcb Descriptor Control Block for the socket
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* @param queue Linked list of buffes to write
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*/
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static int telnetd_write(DCB* dcb, GWBUF* queue)
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{
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int rc;
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rc = dcb_write(dcb, queue);
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return rc;
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}
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/**
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* Handler for the EPOLLERR event.
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*
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* @param dcb The descriptor control block
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*/
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static int telnetd_error(DCB* dcb)
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{
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return 0;
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}
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/**
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* Handler for the EPOLLHUP event.
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*
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* @param dcb The descriptor control block
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*/
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static int telnetd_hangup(DCB* dcb)
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{
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return 0;
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}
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/**
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* Handler for the EPOLLIN event when the DCB refers to the listening
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* socket for the protocol.
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*
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* @param listener The descriptor control block
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* @return The number of new connections created
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*/
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static int telnetd_accept(DCB* client_dcb)
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{
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TELNETD* telnetd_protocol = NULL;
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if ((telnetd_protocol = (TELNETD*)MXS_CALLOC(1, sizeof(TELNETD))) == NULL)
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{
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dcb_close(client_dcb);
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return 0;
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}
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telnetd_protocol->state = TELNETD_STATE_LOGIN;
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telnetd_protocol->username = NULL;
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client_dcb->protocol = (void*)telnetd_protocol;
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if (!session_start(client_dcb->session) || poll_add_dcb(client_dcb))
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{
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dcb_close(client_dcb);
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return 0;
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}
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dcb_printf(client_dcb, "MaxScale login: ");
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return 1;
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}
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/**
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* The close handler for the descriptor. Called by the gateway to
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* explicitly close a connection.
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*
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* @param dcb The descriptor control block
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*/
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static int telnetd_close(DCB* dcb)
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{
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TELNETD* telnetd = static_cast<TELNETD*>(dcb->protocol);
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if (telnetd && telnetd->username)
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{
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MXS_FREE(telnetd->username);
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}
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return 0;
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}
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/**
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* Telnet command implementation
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*
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* Called for each command in the telnet stream.
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*
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* Currently we do no command execution
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*
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* @param dcb The client DCB
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* @param cmd The command stream
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*/
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static void telnetd_command(DCB* dcb, unsigned char* cmd)
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{
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}
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/**
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* Enable or disable telnet protocol echo
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*
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* @param dcb DCB of the telnet connection
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* @param enable Enable or disable echo functionality
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*/
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static void telnetd_echo(DCB* dcb, int enable)
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{
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GWBUF* gwbuf;
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unsigned char* buf;
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if ((gwbuf = gwbuf_alloc(3)) == NULL)
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{
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return;
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}
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buf = GWBUF_DATA(gwbuf);
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buf[0] = TELNET_IAC;
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buf[1] = enable ? TELNET_WONT : TELNET_WILL;
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buf[2] = TELNET_ECHO;
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dcb_write(dcb, gwbuf);
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}
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