498 lines
13 KiB
C
498 lines
13 KiB
C
/*
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* ircd-ratbox: A slightly useful ircd.
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* filter.c: Drop messages we don't like
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*
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* Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
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* Copyright (C) 1996-2002 Hybrid Development Team
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* Copyright (C) 2002-2005 ircd-ratbox development team
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
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* USA
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*
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* $Id$
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*/
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#include "stdinc.h"
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#include "channel.h"
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#include "client.h"
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#include "chmode.h"
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#include "match.h"
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#include "ircd.h"
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#include "numeric.h"
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#include "send.h"
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#include "s_newconf.h"
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#include "s_serv.h"
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#include "s_user.h"
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#include "msg.h"
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#include "parse.h"
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#include "modules.h"
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#include "operhash.h"
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#include "inline/stringops.h"
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#include "msgbuf.h"
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#include <hs_common.h>
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#include <hs_runtime.h>
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#define FILTER_NICK 0
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#define FILTER_USER 0
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#define FILTER_HOST 0
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#define FILTER_EXIT_MSG "Connection closed"
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static const char filter_desc[] = "Filter messages using a precompiled Hyperscan database";
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static void filter_msg_user(void *data);
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static void filter_msg_channel(void *data);
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static void filter_client_quit(void *data);
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static void on_client_exit(void *data);
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static void mo_setfilter(struct MsgBuf *, struct Client *, struct Client *, int, const char **);
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static void me_setfilter(struct MsgBuf *, struct Client *, struct Client *, int, const char **);
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static char *filter_data = NULL;
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static size_t filter_data_len = 0;
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static hs_database_t *filter_db;
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static hs_scratch_t *filter_scratch;
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static int filter_enable = 1;
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static const char *cmdname[MESSAGE_TYPE_COUNT] = {
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[MESSAGE_TYPE_PRIVMSG] = "PRIVMSG",
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[MESSAGE_TYPE_NOTICE] = "NOTICE",
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[MESSAGE_TYPE_PART] = "PART",
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};
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enum filter_state {
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FILTER_EMPTY,
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FILTER_FILLING,
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FILTER_LOADED
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};
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#define ACT_DROP (1 << 0)
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#define ACT_KILL (1 << 1)
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#define ACT_ALARM (1 << 2)
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static enum filter_state state = FILTER_EMPTY;
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static char check_str[21] = "";
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static unsigned filter_chmode, filter_umode;
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mapi_hfn_list_av1 filter_hfnlist[] = {
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{ "privmsg_user", filter_msg_user },
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{ "privmsg_channel", filter_msg_channel },
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{ "client_quit", filter_client_quit },
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{ "client_exit", on_client_exit },
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{ NULL, NULL }
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};
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struct Message setfilter_msgtab = {
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"SETFILTER", 0, 0, 0, 0,
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{mg_unreg, mg_not_oper, mg_ignore, mg_ignore, {me_setfilter, 2}, {mo_setfilter, 2}}
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};
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static int
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modinit(void)
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{
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filter_umode = user_modes['u'] = find_umode_slot();
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construct_umodebuf();
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filter_chmode = cflag_add('u', chm_simple);
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return 0;
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}
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static void
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moddeinit(void)
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{
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if (filter_umode) {
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user_modes['u'] = 0;
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construct_umodebuf();
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}
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if (filter_chmode)
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cflag_orphan('u');
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if (filter_scratch)
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hs_free_scratch(filter_scratch);
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if (filter_db)
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hs_free_database(filter_db);
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if (filter_data)
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rb_free(filter_data);
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}
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mapi_clist_av1 filter_clist[] = { &setfilter_msgtab, NULL };
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DECLARE_MODULE_AV2(filter, modinit, moddeinit, filter_clist, NULL, filter_hfnlist, NULL, "0.4", filter_desc);
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static int
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setfilter(const char *check, const char *data, const char **error)
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{
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if (error) *error = "unknown";
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if (!strcasecmp(data, "disable")) {
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filter_enable = 0;
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sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
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"Filtering disabled.");
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return 0;
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}
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if (!strcasecmp(data, "enable")) {
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filter_enable = 1;
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sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
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"Filtering enabled.");
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return 0;
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}
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if (strlen(check) > sizeof check_str - 1) {
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if (error) *error = "check string too long";
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return -1;
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}
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if (!strcasecmp(data, "new")) {
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if (state == FILTER_FILLING) {
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rb_free(filter_data);
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filter_data = 0;
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filter_data_len = 0;
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}
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state = FILTER_FILLING;
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strcpy(check_str, check);
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return 0;
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}
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if (!strcasecmp(data, "drop")) {
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if (!filter_db) {
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if (error) *error = "no database to drop";
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return -1;
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}
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hs_free_database(filter_db);
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filter_db = 0;
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return 0;
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}
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if (!strcasecmp(data, "abort")) {
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if (state != FILTER_FILLING) {
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if (error) *error = "not filling";
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return -1;
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}
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state = filter_db ? FILTER_LOADED : FILTER_EMPTY;
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rb_free(filter_data);
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filter_data = 0;
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filter_data_len = 0;
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return 0;
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}
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if (strcmp(check, check_str) != 0) {
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if (error) *error = "check strings don't match";
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return -1;
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}
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if (!strcasecmp(data, "apply")) {
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if (state != FILTER_FILLING) {
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if (error) *error = "not loading anything";
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return -1;
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}
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hs_database_t *db;
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hs_error_t r = hs_deserialize_database(filter_data, filter_data_len, &db);
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if (r != HS_SUCCESS) {
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if (error) *error = "couldn't deserialize db";
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return -1;
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}
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r = hs_alloc_scratch(db, &filter_scratch);
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if (r != HS_SUCCESS) {
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if (error) *error = "couldn't allocate scratch";
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hs_free_database(db);
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return -1;
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}
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if (filter_db) {
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hs_free_database(filter_db);
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}
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state = FILTER_LOADED;
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filter_db = db;
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sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
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"New filters loaded.");
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rb_free(filter_data);
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filter_data = 0;
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filter_data_len = 0;
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return 0;
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}
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if (*data != '+') {
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if (error) *error = "unknown command or data doesn't start with +";
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return -1;
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}
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data += 1;
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if (state == FILTER_FILLING) {
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int dl;
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unsigned char *d = rb_base64_decode((unsigned char *)data, strlen(data), &dl);
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if (!d) {
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if (error) *error = "invalid data";
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return -1;
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}
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if (filter_data_len + dl > 10000000ul) {
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if (error) *error = "data over size limit";
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rb_free(d);
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return -1;
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}
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filter_data = rb_realloc(filter_data, filter_data_len + dl);
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memcpy(filter_data + filter_data_len, d, dl);
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rb_free(d);
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filter_data_len += dl;
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} else {
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if (error) *error = "send \"new\" first";
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return -1;
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}
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return 0;
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}
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/* /SETFILTER [server-mask] <check> { NEW | APPLY | <data> }
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* <check> must be the same for the entirety of a new...data...apply run,
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* and exists just to ensure runs don't mix
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* NEW prepares a buffer to receive a hyperscan database
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* <data> is base64 encoded chunks of hyperscan database, which are decoded
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* and appended to the buffer
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* APPLY deserialises the buffer and sets the resulting hyperscan database
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* as the one to use for filtering */
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static void
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mo_setfilter(struct MsgBuf *msgbuf, struct Client *client_p, struct Client *source_p, int parc, const char **parv)
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{
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int for_me = 0;
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const char *check;
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const char *data;
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if (!IsOperAdmin(source_p)) {
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sendto_one(source_p, form_str(ERR_NOPRIVS), me.name, source_p->name, "admin");
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return;
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}
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if (parc == 4) {
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check = parv[2];
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data = parv[3];
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if(match(parv[1], me.name)) {
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for_me = 1;
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}
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sendto_match_servs(source_p, parv[1],
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CAP_ENCAP, NOCAPS,
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"ENCAP %s SETFILTER %s :%s", parv[1], check, data);
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} else if (parc == 3) {
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check = parv[1];
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data = parv[2];
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for_me = 1;
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} else {
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sendto_one_notice(source_p, ":SETFILTER needs 2 or 3 params, have %d", parc - 1);
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return;
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}
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if (for_me) {
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const char *error;
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int r = setfilter(check, data, &error);
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if (r) {
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sendto_one_notice(source_p, ":SETFILTER failed: %s", error);
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} else {
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sendto_one_notice(source_p, ":SETFILTER ok");
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}
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}
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}
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static void
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me_setfilter(struct MsgBuf *msgbuf, struct Client *client_p, struct Client *source_p, int parc, const char **parv)
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{
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if(!IsPerson(source_p))
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return;
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const char *error;
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int r = setfilter(parv[1], parv[2], &error);
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if (r) {
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sendto_one_notice(source_p, ":SETFILTER failed: %s", error);
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}
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return;
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}
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/* will be called for every match
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* hyperscan provides us one piece of information about the expression
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* matched, an integer ID. we're co-opting the lowest 3 bits of this
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* as a flag set. conveniently, this means all we really need to do
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* here is or the IDs together. */
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int match_callback(unsigned id,
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unsigned long long from,
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unsigned long long to,
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unsigned flags,
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void *context_)
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{
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unsigned *context = context_;
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*context |= id;
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return 0;
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}
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static char check_buffer[2000];
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static char clean_buffer[BUFSIZE];
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unsigned match_message(const char *prefix,
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struct Client *source,
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const char *command,
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const char *target,
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const char *msg)
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{
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unsigned state = 0;
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if (!filter_enable)
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return 0;
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if (!filter_db)
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return 0;
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if (!command)
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return 0;
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snprintf(check_buffer, sizeof check_buffer, "%s:%s!%s@%s#%c %s%s%s :%s",
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prefix,
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#if FILTER_NICK
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source->name,
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#else
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"*",
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#endif
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#if FILTER_USER
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source->username,
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#else
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"*",
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#endif
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#if FILTER_HOST
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source->host,
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#else
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"*",
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#endif
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source->user && source->user->suser[0] != '\0' ? '1' : '0',
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command,
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target ? " " : "",
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target ? target : "",
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msg);
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hs_error_t r = hs_scan(filter_db, check_buffer, strlen(check_buffer), 0, filter_scratch, match_callback, &state);
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if (r != HS_SUCCESS && r != HS_SCAN_TERMINATED)
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return 0;
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return state;
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}
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void
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filter_msg_user(void *data_)
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{
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hook_data_privmsg_user *data = data_;
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struct Client *s = data->source_p;
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/* we only need to filter once */
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if (!MyClient(s)) {
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return;
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}
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/* opers are immune to checking, for obvious reasons
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* anything sent to an oper is also immune, because that should make it
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* less impossible to deal with reports. */
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if (IsOper(s) || IsOper(data->target_p)) {
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return;
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}
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if (data->target_p->umodes & filter_umode) {
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return;
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}
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char *text = strcpy(clean_buffer, data->text);
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strip_colour(text);
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strip_unprintable(text);
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unsigned r = match_message("0", s, cmdname[data->msgtype], "0", data->text) |
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match_message("1", s, cmdname[data->msgtype], "0", text);
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if (r & ACT_DROP) {
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if (data->msgtype == MESSAGE_TYPE_PRIVMSG) {
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sendto_one_numeric(s, ERR_CANNOTSENDTOCHAN,
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form_str(ERR_CANNOTSENDTOCHAN),
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data->target_p->name);
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}
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data->approved = 1;
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}
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if (r & ACT_ALARM) {
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sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
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"FILTER: %s!%s@%s [%s]",
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s->name, s->username, s->host, s->sockhost);
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}
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if (r & ACT_KILL) {
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data->approved = 1;
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exit_client(NULL, s, s, FILTER_EXIT_MSG);
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}
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}
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void
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filter_msg_channel(void *data_)
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{
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hook_data_privmsg_channel *data = data_;
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struct Client *s = data->source_p;
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/* we only need to filter once */
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if (!MyClient(s)) {
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return;
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}
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/* just normal oper immunity for channels. i'd like to have a mode that
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* disables the filter per-channel, but that's for the future */
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if (IsOper(s)) {
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return;
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}
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if (data->chptr->mode.mode & filter_chmode) {
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return;
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}
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char *text = strcpy(clean_buffer, data->text);
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strip_colour(text);
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strip_unprintable(text);
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unsigned r = match_message("0", s, cmdname[data->msgtype], data->chptr->chname, data->text) |
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match_message("1", s, cmdname[data->msgtype], data->chptr->chname, text);
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if (r & ACT_DROP) {
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if (data->msgtype == MESSAGE_TYPE_PRIVMSG) {
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sendto_one_numeric(s, ERR_CANNOTSENDTOCHAN,
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form_str(ERR_CANNOTSENDTOCHAN),
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data->chptr->chname);
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}
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data->approved = 1;
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}
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if (r & ACT_ALARM) {
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sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
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"FILTER: %s!%s@%s [%s]",
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s->name, s->username, s->host, s->sockhost);
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}
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if (r & ACT_KILL) {
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data->approved = 1;
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exit_client(NULL, s, s, FILTER_EXIT_MSG);
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}
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}
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void
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filter_client_quit(void *data_)
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{
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hook_data_client_quit *data = data_;
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struct Client *s = data->client;
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if (IsOper(s)) {
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return;
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}
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char *text = strcpy(clean_buffer, data->orig_reason);
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strip_colour(text);
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strip_unprintable(text);
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unsigned r = match_message("0", s, "QUIT", NULL, data->orig_reason) |
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match_message("1", s, "QUIT", NULL, text);
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if (r & ACT_DROP) {
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data->reason = NULL;
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}
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if (r & ACT_ALARM) {
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sendto_realops_snomask(SNO_GENERAL, L_ALL | L_NETWIDE,
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"FILTER: %s!%s@%s [%s]",
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s->name, s->username, s->host, s->sockhost);
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}
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/* No point in doing anything with ACT_KILL */
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}
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void
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on_client_exit(void *data_)
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{
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/* If we see a netsplit, abort the current FILTER_FILLING attempt */
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hook_data_client_exit *data = data_;
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if (!IsServer(data->target)) return;
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if (state == FILTER_FILLING) {
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state = filter_db ? FILTER_LOADED : FILTER_EMPTY;
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}
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}
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