ngircd-tor/src/ngircd/parse.c

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/*
* ngIRCd -- The Next Generation IRC Daemon
* Copyright (c)2001-2014 Alexander Barton (alex@barton.de) and Contributors.
*
* 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; either version 2 of the License, or
* (at your option) any later version.
* Please read the file COPYING, README and AUTHORS for more information.
*/
#include "portab.h"
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/**
* @file
* IRC command parser and validator.
*/
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include "ngircd.h"
#include "conn-func.h"
#include "conf.h"
#include "channel.h"
#include "log.h"
#include "messages.h"
#include "parse.h"
#include "irc.h"
#include "irc-cap.h"
#include "irc-channel.h"
#ifdef ICONV
# include "irc-encoding.h"
#endif
#include "irc-info.h"
#include "irc-login.h"
#include "irc-metadata.h"
#include "irc-mode.h"
#include "irc-op.h"
#include "irc-oper.h"
#include "irc-server.h"
#include "irc-write.h"
#include "numeric.h"
struct _NUMERIC {
int numeric;
bool (*function) PARAMS(( CLIENT *Client, REQUEST *Request ));
};
static COMMAND My_Commands[] =
{
#define _CMD(name, func, type, min, max, penalty) \
{ (name), (func), (type), (min), (max), (penalty), 0, 0, 0 }
_CMD("ADMIN", IRC_ADMIN, CLIENT_USER|CLIENT_SERVER, 0, 1, 1),
_CMD("AWAY", IRC_AWAY, CLIENT_USER, 0, 1, 0),
_CMD("CAP", IRC_CAP, CLIENT_ANY, 1, 2, 0),
_CMD("CONNECT", IRC_CONNECT, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
#ifdef STRICT_RFC
_CMD("DIE", IRC_DIE, CLIENT_USER, 0, 0, 0),
#else
_CMD("DIE", IRC_DIE, CLIENT_USER, 0, 1, 0),
#endif
_CMD("DISCONNECT", IRC_DISCONNECT, CLIENT_USER, 1, 1, 0),
_CMD("ERROR", IRC_ERROR, CLIENT_ANY, 0, -1, 0),
_CMD("GLINE", IRC_xLINE, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
_CMD("HELP", IRC_HELP, CLIENT_USER, 0, 1, 2),
_CMD("INFO", IRC_INFO, CLIENT_USER|CLIENT_SERVER, 0, 1, 2),
_CMD("INVITE", IRC_INVITE, CLIENT_USER|CLIENT_SERVER, 2, 2, 0),
_CMD("ISON", IRC_ISON, CLIENT_USER, 1, -1, 0),
_CMD("JOIN", IRC_JOIN, CLIENT_USER|CLIENT_SERVER, 1, 2, 0),
_CMD("KICK", IRC_KICK, CLIENT_USER|CLIENT_SERVER, 2, 3, 0),
_CMD("KILL", IRC_KILL, CLIENT_USER|CLIENT_SERVER, 2, 2, 0),
_CMD("KLINE", IRC_xLINE, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
_CMD("LINKS", IRC_LINKS, CLIENT_USER|CLIENT_SERVER, 0, 2, 1),
_CMD("LIST", IRC_LIST, CLIENT_USER|CLIENT_SERVER, 0, 2, 2),
_CMD("LUSERS", IRC_LUSERS, CLIENT_USER|CLIENT_SERVER, 0, 2, 1),
_CMD("METADATA", IRC_METADATA, CLIENT_SERVER, 3, 3, 0),
_CMD("MODE", IRC_MODE, CLIENT_USER|CLIENT_SERVER, 1, -1, 1),
_CMD("MOTD", IRC_MOTD, CLIENT_USER|CLIENT_SERVER, 0, 1, 3),
_CMD("NAMES", IRC_NAMES, CLIENT_USER|CLIENT_SERVER, 0, 2, 1),
_CMD("NICK", IRC_NICK, CLIENT_ANY, 0, -1, 0),
_CMD("NJOIN", IRC_NJOIN, CLIENT_SERVER, 2, 2, 0),
_CMD("NOTICE", IRC_NOTICE, CLIENT_ANY, 0, -1, 0),
_CMD("OPER", IRC_OPER, CLIENT_USER, 2, 2, 0),
_CMD("PART", IRC_PART, CLIENT_USER|CLIENT_SERVER, 1, 2, 0),
_CMD("PASS", IRC_PASS, CLIENT_ANY, 0, -1, 0),
_CMD("PING", IRC_PING, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
_CMD("PONG", IRC_PONG, CLIENT_ANY, 0, -1, 0),
_CMD("PRIVMSG", IRC_PRIVMSG, CLIENT_USER|CLIENT_SERVER, 0, 2, 0),
_CMD("QUIT", IRC_QUIT, CLIENT_ANY, 0, 1, 0),
_CMD("REHASH", IRC_REHASH, CLIENT_USER, 0, 0, 0),
_CMD("RESTART", IRC_RESTART, CLIENT_USER, 0, 0, 0),
_CMD("SERVER", IRC_SERVER, CLIENT_ANY, 0, -1, 0),
_CMD("SERVICE", IRC_SERVICE, CLIENT_ANY, 6, 6, 0),
_CMD("SERVLIST", IRC_SERVLIST, CLIENT_USER, 0, 2, 1),
_CMD("SQUERY", IRC_SQUERY, CLIENT_USER|CLIENT_SERVER, 0, 2, 0),
_CMD("SQUIT", IRC_SQUIT, CLIENT_USER|CLIENT_SERVER, 2, 2, 0),
_CMD("STATS", IRC_STATS, CLIENT_USER|CLIENT_SERVER, 0, 2, 2),
_CMD("SVSNICK", IRC_SVSNICK, CLIENT_SERVER, 2, 2, 0),
_CMD("SUMMON", IRC_SUMMON, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
_CMD("TIME", IRC_TIME, CLIENT_USER|CLIENT_SERVER, 0, 1, 1),
_CMD("TOPIC", IRC_TOPIC, CLIENT_USER|CLIENT_SERVER, 1, 2, 1),
_CMD("TRACE", IRC_TRACE, CLIENT_USER|CLIENT_SERVER, 0, 1, 3),
_CMD("USER", IRC_USER, CLIENT_ANY, 0, -1, 0),
_CMD("USERHOST", IRC_USERHOST, CLIENT_USER, 1, -1, 1),
_CMD("USERS", IRC_USERS, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
_CMD("VERSION", IRC_VERSION, CLIENT_USER|CLIENT_SERVER, 0, 1, 1),
_CMD("WALLOPS", IRC_WALLOPS, CLIENT_USER|CLIENT_SERVER, 1, 1, 0),
_CMD("WEBIRC", IRC_WEBIRC, CLIENT_UNKNOWN, 4, 4, 0),
_CMD("WHO", IRC_WHO, CLIENT_USER, 0, 2, 1),
_CMD("WHOIS", IRC_WHOIS, CLIENT_USER|CLIENT_SERVER, 0, -1, 1),
_CMD("WHOWAS", IRC_WHOWAS, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
#ifdef IRCPLUS
_CMD("CHANINFO", IRC_CHANINFO, CLIENT_SERVER, 0, -1, 0),
# ifdef ICONV
_CMD("CHARCONV", IRC_CHARCONV, CLIENT_USER, 1, 1, 0),
# endif
#endif
#ifndef STRICT_RFC
_CMD("GET", IRC_QUIT_HTTP, CLIENT_UNKNOWN, 0, -1, 0),
_CMD("POST", IRC_QUIT_HTTP, CLIENT_UNKNOWN, 0, -1, 0),
#endif
_CMD(NULL, NULL, 0, 0, 0, 0) /* End-Mark */
#undef _CMD
};
static void Init_Request PARAMS(( REQUEST *Req ));
static bool Validate_Prefix PARAMS(( CONN_ID Idx, REQUEST *Req, bool *Closed ));
static bool Validate_Command PARAMS(( CONN_ID Idx, REQUEST *Req, bool *Closed ));
static bool Validate_Args PARAMS(( CONN_ID Idx, REQUEST *Req, bool *Closed ));
static bool Handle_Request PARAMS(( CONN_ID Idx, REQUEST *Req ));
static bool ScrubCTCP PARAMS((char *Request));
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/**
* Return the pointer to the global "IRC command structure".
* This structure, an array of type "COMMAND" describes all the IRC commands
* implemented by ngIRCd and how to handle them.
* @return Pointer to the global command structure.
*/
GLOBAL COMMAND *
Parse_GetCommandStruct( void )
{
return My_Commands;
} /* Parse_GetCommandStruct */
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/**
* Parse a command ("request") received from a client.
*
* This function is called after the connection layer received a valid CR+LF
* terminated line of text: we assume that this is a valid IRC command and
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* try to do something useful with it :-)
*
* All errors are reported to the client from which the command has been
* received, and if the error is fatal this connection is closed down.
*
* This function is able to parse the syntax as described in RFC 2812,
* section 2.3.
*
* @param Idx Index of the connection from which the command has been received.
* @param Request NULL terminated line of text (the "command").
* @return true on success (valid command or "regular" error), false if a
* fatal error occurred and the connection has been shut down.
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*/
GLOBAL bool
Parse_Request( CONN_ID Idx, char *Request )
{
REQUEST req;
char *start, *ptr;
bool closed;
assert( Idx >= 0 );
assert( Request != NULL );
#ifdef SNIFFER
if( NGIRCd_Sniffer ) Log( LOG_DEBUG, " <- connection %d: '%s'.", Idx, Request );
#endif
Init_Request( &req );
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/* remove leading & trailing whitespace */
ngt_TrimStr( Request );
if (Conf_ScrubCTCP && ScrubCTCP(Request))
return true;
if (Request[0] == ':') {
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/* Prefix */
req.prefix = Request + 1;
ptr = strchr( Request, ' ' );
if( ! ptr )
{
LogDebug("Connection %d: Parse error: prefix without command!?", Idx);
return Conn_WriteStr(Idx, "ERROR :Prefix without command");
}
*ptr = '\0';
#ifndef STRICT_RFC
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/* ignore multiple spaces between prefix and command */
while( *(ptr + 1) == ' ' ) ptr++;
#endif
start = ptr + 1;
}
else start = Request;
ptr = strchr( start, ' ' );
if( ptr )
{
*ptr = '\0';
#ifndef STRICT_RFC
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/* ignore multiple spaces between parameters */
while( *(ptr + 1) == ' ' ) ptr++;
#endif
}
req.command = start;
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/* Arguments, Parameters */
if( ptr )
{
start = ptr + 1;
while( start )
{
if( start[0] == ':' )
{
req.argv[req.argc] = start + 1;
ptr = NULL;
}
else
{
req.argv[req.argc] = start;
ptr = strchr( start, ' ' );
if( ptr )
{
*ptr = '\0';
#ifndef STRICT_RFC
while( *(ptr + 1) == ' ' ) ptr++;
#endif
}
}
req.argc++;
if( start[0] == ':' ) break;
if( req.argc > 14 ) break;
if( ptr ) start = ptr + 1;
else start = NULL;
}
}
if( ! Validate_Prefix( Idx, &req, &closed )) return ! closed;
if( ! Validate_Command( Idx, &req, &closed )) return ! closed;
if( ! Validate_Args( Idx, &req, &closed )) return ! closed;
return Handle_Request( Idx, &req );
} /* Parse_Request */
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/**
* Initialize request structure.
* @param Req Request structure to be initialized.
*/
static void
Init_Request( REQUEST *Req )
{
int i;
assert( Req != NULL );
Req->prefix = NULL;
Req->command = NULL;
for( i = 0; i < 15; Req->argv[i++] = NULL );
Req->argc = 0;
} /* Init_Request */
static bool
Validate_Prefix( CONN_ID Idx, REQUEST *Req, bool *Closed )
{
CLIENT *client, *c;
assert( Idx >= 0 );
assert( Req != NULL );
*Closed = false;
client = Conn_GetClient( Idx );
assert( client != NULL );
if (!Req->prefix && Client_Type(client) == CLIENT_SERVER
&& !(Conn_Options(Idx) & CONN_RFC1459)
&& strcasecmp(Req->command, "ERROR") != 0
&& strcasecmp(Req->command, "PING") != 0)
{
Log(LOG_ERR,
"Received command without prefix (connection %d, command \"%s\")!?",
Idx, Req->command);
if (!Conn_WriteStr(Idx, "ERROR :Prefix missing"))
*Closed = true;
return false;
}
if (!Req->prefix)
return true;
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/* only validate if this connection is already registered */
if (Client_Type(client) != CLIENT_USER
&& Client_Type(client) != CLIENT_SERVER
&& Client_Type(client) != CLIENT_SERVICE) {
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/* not registered, ignore prefix */
Req->prefix = NULL;
return true;
}
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/* check if client in prefix is known */
c = Client_Search(Req->prefix);
if (!c) {
if (Client_Type(client) != CLIENT_SERVER) {
Log(LOG_ERR,
"Ignoring command with invalid prefix \"%s\" from \"%s\" (connection %d, command \"%s\")!",
Req->prefix, Client_ID(client), Idx, Req->command);
if (!Conn_WriteStr(Idx,
"ERROR :Invalid prefix \"%s\"",
Req->prefix))
*Closed = true;
IRC_SetPenalty(client, 2);
} else
LogDebug("Ignoring command with invalid prefix \"%s\" from \"%s\" (connection %d, command \"%s\")!",
Req->prefix, Client_ID(client), Idx, Req->command);
return false;
}
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/* check if the client named in the prefix is expected
* to come from that direction */
if (Client_NextHop(c) != client) {
if (Client_Type(client) != CLIENT_SERVER) {
Log(LOG_ERR,
"Spoofed prefix \"%s\" from \"%s\" (connection %d, command \"%s\"), closing connection!",
Req->prefix, Client_ID(client), Idx, Req->command);
Conn_Close(Idx, NULL, "Spoofed prefix", true);
*Closed = true;
} else {
Log(LOG_WARNING,
"Ignoring command with spoofed prefix \"%s\" from \"%s\" (connection %d, command \"%s\")!",
Req->prefix, Client_ID(client), Idx, Req->command);
}
return false;
}
return true;
} /* Validate_Prefix */
static bool
Validate_Command( UNUSED CONN_ID Idx, UNUSED REQUEST *Req, bool *Closed )
{
assert( Idx >= 0 );
assert( Req != NULL );
*Closed = false;
return true;
} /* Validate_Command */
static bool
#ifdef STRICT_RFC
Validate_Args(CONN_ID Idx, REQUEST *Req, bool *Closed)
#else
Validate_Args(UNUSED CONN_ID Idx, UNUSED REQUEST *Req, bool *Closed)
#endif
{
#ifdef STRICT_RFC
int i;
#endif
*Closed = false;
#ifdef STRICT_RFC
assert( Idx >= 0 );
assert( Req != NULL );
/* CR and LF are never allowed in command parameters.
* But since we do accept lines terminated only with CR or LF in
* "non-RFC-compliant mode" (besides the correct CR+LF combination),
* this check can only trigger in "strict RFC" mode; therefore we
* optimize it away otherwise ... */
for (i = 0; i < Req->argc; i++) {
if (strchr(Req->argv[i], '\r') || strchr(Req->argv[i], '\n')) {
Log(LOG_ERR,
"Invalid character(s) in parameter (connection %d, command %s)!?",
Idx, Req->command);
if (!Conn_WriteStr(Idx,
"ERROR :Invalid character(s) in parameter!"))
*Closed = true;
return false;
}
}
#endif
return true;
} /* Validate_Args */
/* Command is a status code ("numeric") from another server */
static bool
Handle_Numeric(CLIENT *client, REQUEST *Req)
{
static const struct _NUMERIC Numerics[] = {
{ 5, IRC_Num_ISUPPORT },
{ 20, NULL },
{ 376, IRC_Num_ENDOFMOTD }
};
int i, num;
char str[COMMAND_LEN];
CLIENT *prefix, *target = NULL;
/* Determine target */
if (Req->argc > 0) {
if (strcmp(Req->argv[0], "*") != 0)
target = Client_Search(Req->argv[0]);
else
target = Client_ThisServer();
}
if (!target) {
/* Status code without target!? */
if (Req->argc > 0)
Log(LOG_WARNING,
"Unknown target for status code %s: \"%s\"",
Req->command, Req->argv[0]);
else
Log(LOG_WARNING,
"Unknown target for status code %s!",
Req->command);
return true;
}
if (target == Client_ThisServer()) {
/* This server is the target of the numeric */
num = atoi(Req->command);
for (i = 0; i < (int) C_ARRAY_SIZE(Numerics); i++) {
if (num == Numerics[i].numeric) {
if (!Numerics[i].function)
return CONNECTED;
return Numerics[i].function(client, Req);
}
}
LogDebug("Ignored status code %s from \"%s\".",
Req->command, Client_ID(client));
return true;
}
/* Determine source */
if (! Req->prefix[0]) {
/* Oops, no prefix!? */
Log(LOG_WARNING, "Got status code %s from \"%s\" without prefix!?",
Req->command, Client_ID(client));
return true;
}
prefix = Client_Search(Req->prefix);
if (! prefix) { /* Oops, unknown prefix!? */
Log(LOG_WARNING, "Got status code %s from unknown source: \"%s\"", Req->command, Req->prefix);
return true;
}
/* Forward status code */
strlcpy(str, Req->command, sizeof(str));
for (i = 0; i < Req->argc; i++) {
if (i < Req->argc - 1)
strlcat(str, " ", sizeof(str));
else
strlcat(str, " :", sizeof(str));
strlcat(str, Req->argv[i], sizeof(str));
}
return IRC_WriteStrClientPrefix(target, prefix, "%s", str);
}
static bool
Handle_Request( CONN_ID Idx, REQUEST *Req )
{
CLIENT *client;
bool result = true;
int client_type;
COMMAND *cmd;
assert( Idx >= 0 );
assert( Req != NULL );
assert( Req->command != NULL );
client = Conn_GetClient( Idx );
assert( client != NULL );
/* Numeric? */
client_type = Client_Type(client);
if ((client_type == CLIENT_SERVER ||
client_type == CLIENT_UNKNOWNSERVER)
&& strlen(Req->command) == 3 && atoi(Req->command) > 1)
return Handle_Numeric(client, Req);
cmd = My_Commands;
while (cmd->name) {
if (strcasecmp(Req->command, cmd->name) != 0) {
cmd++;
continue;
}
if (!(client_type & cmd->type)) {
if (client_type == CLIENT_USER
&& cmd->type & CLIENT_SERVER)
return IRC_WriteErrClient(client,
ERR_NOTREGISTEREDSERVER_MSG,
Client_ID(client));
else
return IRC_WriteErrClient(client,
ERR_NOTREGISTERED_MSG,
Client_ID(client));
}
if (cmd->penalty)
IRC_SetPenalty(client, cmd->penalty);
if (Req->argc < cmd->min_argc ||
(cmd->max_argc != -1 && Req->argc > cmd->max_argc))
return IRC_WriteErrClient(client, ERR_NEEDMOREPARAMS_MSG,
Client_ID(client), Req->command);
/* Command is allowed for this client: call it and count
* generated bytes in output */
Conn_ResetWCounter();
result = (cmd->function)(client, Req);
cmd->bytes += Conn_WCounter();
/* Adjust counters */
if (client_type != CLIENT_SERVER)
cmd->lcount++;
else
cmd->rcount++;
return result;
}
if (client_type != CLIENT_USER &&
client_type != CLIENT_SERVER &&
client_type != CLIENT_SERVICE )
return true;
/* Unknown command and registered connection: generate error: */
LogDebug("Connection %d: Unknown command \"%s\", %d %s,%s prefix.",
Client_Conn( client ), Req->command, Req->argc,
Req->argc == 1 ? "parameter" : "parameters",
Req->prefix ? "" : " no" );
if (Client_Type(client) != CLIENT_SERVER)
result = IRC_WriteErrClient(client, ERR_UNKNOWNCOMMAND_MSG,
Client_ID(client), Req->command);
return result;
} /* Handle_Request */
/**
* Check if incoming messages contains CTCP commands and should be dropped.
*
* @param Request NULL terminated incoming command.
* @returns true, when the message should be dropped.
*/
static bool
ScrubCTCP(char *Request)
{
static const char me_cmd[] = "ACTION ";
static const char ctcp_char = 0x1;
bool dropCommand = false;
char *ptr = Request;
char *ptrEnd = strchr(Request, '\0');
if (Request[0] == ':' && ptrEnd > ptr)
ptr++;
while (ptr != ptrEnd && *ptr != ':')
ptr++;
if ((ptrEnd - ptr) > 1) {
ptr++;
if (*ptr == ctcp_char) {
dropCommand = true;
ptr++;
/* allow /me commands */
if ((size_t)(ptrEnd - ptr) >= strlen(me_cmd)
&& !strncmp(ptr, me_cmd, strlen(me_cmd)))
dropCommand = false;
}
}
return dropCommand;
}
/* -eof- */