Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 1 | /* IRC extension for IP connection tracking, Version 1.21 |
| 2 | * (C) 2000-2002 by Harald Welte <laforge@gnumonks.org> |
| 3 | * based on RR's ip_conntrack_ftp.c |
Patrick McHardy | f229f6c | 2013-04-06 15:24:29 +0200 | [diff] [blame] | 4 | * (C) 2006-2012 Patrick McHardy <kaber@trash.net> |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the License, or (at your option) any later version. |
| 10 | */ |
| 11 | |
Pablo Neira Ayuso | ad6d950 | 2016-01-03 22:41:24 +0100 | [diff] [blame] | 12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 13 | |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 14 | #include <linux/module.h> |
| 15 | #include <linux/moduleparam.h> |
| 16 | #include <linux/skbuff.h> |
| 17 | #include <linux/in.h> |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 18 | #include <linux/ip.h> |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 19 | #include <linux/tcp.h> |
| 20 | #include <linux/netfilter.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 21 | #include <linux/slab.h> |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 22 | #include <linux/list.h> |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 23 | |
| 24 | #include <net/netfilter/nf_conntrack.h> |
| 25 | #include <net/netfilter/nf_conntrack_expect.h> |
| 26 | #include <net/netfilter/nf_conntrack_helper.h> |
| 27 | #include <linux/netfilter/nf_conntrack_irc.h> |
| 28 | |
| 29 | #define MAX_PORTS 8 |
| 30 | static unsigned short ports[MAX_PORTS]; |
Stephen Hemminger | 2f0d2f1 | 2008-01-31 04:08:10 -0800 | [diff] [blame] | 31 | static unsigned int ports_c; |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 32 | static unsigned int max_dcc_channels = 8; |
| 33 | static unsigned int dcc_timeout __read_mostly = 300; |
| 34 | /* This is slow, but it's simple. --RR */ |
| 35 | static char *irc_buffer; |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 36 | struct irc_client_info { |
| 37 | char *nickname; |
| 38 | bool conn_to_server; |
| 39 | int nickname_len; |
| 40 | __be32 server_ip; |
| 41 | __be32 client_ip; |
| 42 | struct list_head ptr; |
| 43 | }; |
| 44 | |
| 45 | static struct irc_client_info client_list; |
| 46 | |
| 47 | static unsigned int no_of_clients; |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 48 | static DEFINE_SPINLOCK(irc_buffer_lock); |
| 49 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 50 | unsigned int (*nf_nat_irc_hook)(struct sk_buff *skb, |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 51 | enum ip_conntrack_info ctinfo, |
Patrick McHardy | 051966c | 2012-08-26 19:14:04 +0200 | [diff] [blame] | 52 | unsigned int protoff, |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 53 | unsigned int matchoff, |
| 54 | unsigned int matchlen, |
| 55 | struct nf_conntrack_expect *exp) __read_mostly; |
| 56 | EXPORT_SYMBOL_GPL(nf_nat_irc_hook); |
| 57 | |
| 58 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); |
| 59 | MODULE_DESCRIPTION("IRC (DCC) connection tracking helper"); |
| 60 | MODULE_LICENSE("GPL"); |
| 61 | MODULE_ALIAS("ip_conntrack_irc"); |
Pablo Neira Ayuso | 4dc06f9 | 2008-11-17 16:01:42 +0100 | [diff] [blame] | 62 | MODULE_ALIAS_NFCT_HELPER("irc"); |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 63 | |
| 64 | module_param_array(ports, ushort, &ports_c, 0400); |
| 65 | MODULE_PARM_DESC(ports, "port numbers of IRC servers"); |
| 66 | module_param(max_dcc_channels, uint, 0400); |
| 67 | MODULE_PARM_DESC(max_dcc_channels, "max number of expected DCC channels per " |
| 68 | "IRC session"); |
| 69 | module_param(dcc_timeout, uint, 0400); |
| 70 | MODULE_PARM_DESC(dcc_timeout, "timeout on for unestablished DCC channels"); |
| 71 | |
Jan Engelhardt | 58c0fb0 | 2008-04-14 11:15:42 +0200 | [diff] [blame] | 72 | static const char *const dccprotos[] = { |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 73 | "SEND ", "CHAT ", "MOVE ", "TSEND ", "SCHAT " |
| 74 | }; |
| 75 | |
| 76 | #define MINMATCHLEN 5 |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 77 | #define MINLENNICK 1 |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 78 | /* tries to get the ip_addr and port out of a dcc command |
| 79 | * return value: -1 on failure, 0 on success |
| 80 | * data pointer to first byte of DCC command data |
| 81 | * data_end pointer to last byte of dcc command data |
| 82 | * ip returns parsed ip of dcc command |
| 83 | * port returns parsed port of dcc command |
| 84 | * ad_beg_p returns pointer to first byte of addr data |
| 85 | * ad_end_p returns pointer to last byte of addr data |
| 86 | */ |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 87 | static struct irc_client_info *search_client_by_ip |
| 88 | ( |
| 89 | struct nf_conntrack_tuple *tuple |
| 90 | ) |
| 91 | { |
| 92 | struct irc_client_info *temp, *ret = NULL; |
| 93 | struct list_head *obj_ptr, *prev_obj_ptr; |
| 94 | |
| 95 | list_for_each_safe(obj_ptr, prev_obj_ptr, &client_list.ptr) { |
| 96 | temp = list_entry(obj_ptr, struct irc_client_info, ptr); |
| 97 | if ((temp->client_ip == tuple->src.u3.ip) && |
| 98 | (temp->server_ip == tuple->dst.u3.ip)) |
| 99 | ret = temp; |
| 100 | } |
| 101 | return ret; |
| 102 | } |
| 103 | |
Harvey Harrison | f940964 | 2009-03-28 15:38:30 +0000 | [diff] [blame] | 104 | static int parse_dcc(char *data, const char *data_end, __be32 *ip, |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 105 | u_int16_t *port, char **ad_beg_p, char **ad_end_p) |
| 106 | { |
Patrick McHardy | e3b802b | 2008-09-07 18:21:24 -0700 | [diff] [blame] | 107 | char *tmp; |
| 108 | |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 109 | /* at least 12: "AAAAAAAA P\1\n" */ |
| 110 | while (*data++ != ' ') |
| 111 | if (data > data_end - 12) |
| 112 | return -1; |
| 113 | |
Patrick McHardy | e3b802b | 2008-09-07 18:21:24 -0700 | [diff] [blame] | 114 | /* Make sure we have a newline character within the packet boundaries |
| 115 | * because simple_strtoul parses until the first invalid character. */ |
| 116 | for (tmp = data; tmp <= data_end; tmp++) |
| 117 | if (*tmp == '\n') |
| 118 | break; |
| 119 | if (tmp > data_end || *tmp != '\n') |
| 120 | return -1; |
| 121 | |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 122 | *ad_beg_p = data; |
Harvey Harrison | f940964 | 2009-03-28 15:38:30 +0000 | [diff] [blame] | 123 | *ip = cpu_to_be32(simple_strtoul(data, &data, 10)); |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 124 | |
| 125 | /* skip blanks between ip and port */ |
| 126 | while (*data == ' ') { |
| 127 | if (data >= data_end) |
| 128 | return -1; |
| 129 | data++; |
| 130 | } |
| 131 | |
| 132 | *port = simple_strtoul(data, &data, 10); |
| 133 | *ad_end_p = data; |
| 134 | |
| 135 | return 0; |
| 136 | } |
| 137 | |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 138 | static bool mangle_ip(struct nf_conn *ct, |
| 139 | int dir, char *nick_start) |
| 140 | { |
| 141 | char *nick_end; |
| 142 | struct nf_conntrack_tuple *tuple; |
| 143 | struct irc_client_info *temp; |
| 144 | struct list_head *obj_ptr, *prev_obj_ptr; |
| 145 | |
| 146 | tuple = &ct->tuplehash[dir].tuple; |
| 147 | nick_end = nick_start; |
| 148 | while (*nick_end != ' ') |
| 149 | nick_end++; |
| 150 | list_for_each_safe(obj_ptr, prev_obj_ptr, |
| 151 | &client_list.ptr) { |
| 152 | temp = list_entry(obj_ptr, |
| 153 | struct irc_client_info, ptr); |
| 154 | /*If it is an internal client, |
| 155 | *do not mangle the DCC Server IP |
| 156 | */ |
| 157 | if ((temp->server_ip == tuple->dst.u3.ip) && |
Ravinder Konka | 1d04b7e | 2015-08-03 18:24:34 +0530 | [diff] [blame] | 158 | (temp->nickname_len == (nick_end - nick_start))) { |
| 159 | if (memcmp(nick_start, temp->nickname, |
| 160 | temp->nickname_len) == 0) |
| 161 | return false; |
| 162 | } |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 163 | } |
| 164 | return true; |
| 165 | } |
| 166 | |
| 167 | static int handle_nickname(struct nf_conn *ct, |
| 168 | int dir, char *nick_start) |
| 169 | { |
| 170 | char *nick_end; |
| 171 | struct nf_conntrack_tuple *tuple; |
| 172 | struct irc_client_info *temp; |
| 173 | int i, j; |
| 174 | bool add_entry = true; |
| 175 | |
| 176 | nick_end = nick_start; |
| 177 | i = 0; |
| 178 | while (*nick_end != '\n') { |
| 179 | nick_end++; |
| 180 | i++; |
| 181 | } |
| 182 | tuple = &ct->tuplehash[dir].tuple; |
| 183 | /*Check if the entry is already |
| 184 | * present for that client |
| 185 | */ |
| 186 | temp = search_client_by_ip(tuple); |
| 187 | if (temp) { |
| 188 | add_entry = false; |
| 189 | /*Update nickname if the client is not already |
| 190 | * connected to the server.If the client is |
| 191 | * connected, wait for server to confirm |
| 192 | * if nickname is valid |
| 193 | */ |
| 194 | if (!temp->conn_to_server) { |
| 195 | kfree(temp->nickname); |
| 196 | temp->nickname = |
| 197 | kmalloc(i, GFP_ATOMIC); |
| 198 | if (temp->nickname) { |
| 199 | temp->nickname_len = i; |
Ravinder Konka | 1d04b7e | 2015-08-03 18:24:34 +0530 | [diff] [blame] | 200 | memcpy(temp->nickname, |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 201 | nick_start, temp->nickname_len); |
| 202 | } else { |
| 203 | list_del(&temp->ptr); |
| 204 | no_of_clients--; |
| 205 | kfree(temp); |
| 206 | } |
| 207 | } |
| 208 | } |
| 209 | /*Add client entry if not already present*/ |
| 210 | if (add_entry) { |
| 211 | j = sizeof(struct irc_client_info); |
| 212 | temp = kmalloc(j, GFP_ATOMIC); |
| 213 | if (temp) { |
| 214 | no_of_clients++; |
| 215 | tuple = &ct->tuplehash[dir].tuple; |
| 216 | temp->nickname_len = i; |
| 217 | temp->nickname = |
| 218 | kmalloc(temp->nickname_len, GFP_ATOMIC); |
| 219 | if (!temp->nickname) { |
| 220 | kfree(temp); |
| 221 | return NF_DROP; |
| 222 | } |
| 223 | memcpy(temp->nickname, nick_start, |
| 224 | temp->nickname_len); |
| 225 | memcpy(&temp->client_ip, |
| 226 | &tuple->src.u3.ip, sizeof(__be32)); |
| 227 | memcpy(&temp->server_ip, |
| 228 | &tuple->dst.u3.ip, sizeof(__be32)); |
| 229 | temp->conn_to_server = false; |
| 230 | list_add(&temp->ptr, |
| 231 | &client_list.ptr); |
| 232 | } else { |
| 233 | return NF_DROP; |
| 234 | } |
| 235 | } |
| 236 | return NF_ACCEPT; |
| 237 | } |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 238 | static int help(struct sk_buff *skb, unsigned int protoff, |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 239 | struct nf_conn *ct, enum ip_conntrack_info ctinfo) |
| 240 | { |
| 241 | unsigned int dataoff; |
Jan Engelhardt | 58c0fb0 | 2008-04-14 11:15:42 +0200 | [diff] [blame] | 242 | const struct iphdr *iph; |
| 243 | const struct tcphdr *th; |
| 244 | struct tcphdr _tcph; |
| 245 | const char *data_limit; |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 246 | char *data, *ib_ptr, *for_print, *nick_end; |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 247 | int dir = CTINFO2DIR(ctinfo); |
| 248 | struct nf_conntrack_expect *exp; |
| 249 | struct nf_conntrack_tuple *tuple; |
Harvey Harrison | f940964 | 2009-03-28 15:38:30 +0000 | [diff] [blame] | 250 | __be32 dcc_ip; |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 251 | u_int16_t dcc_port; |
| 252 | __be16 port; |
| 253 | int i, ret = NF_ACCEPT; |
| 254 | char *addr_beg_p, *addr_end_p; |
| 255 | typeof(nf_nat_irc_hook) nf_nat_irc; |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 256 | struct irc_client_info *temp; |
| 257 | bool mangle = true; |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 258 | |
| 259 | /* Until there's been traffic both ways, don't look in packets. */ |
Eric Dumazet | fb04883 | 2011-05-19 15:44:27 +0200 | [diff] [blame] | 260 | if (ctinfo != IP_CT_ESTABLISHED && ctinfo != IP_CT_ESTABLISHED_REPLY) |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 261 | return NF_ACCEPT; |
| 262 | |
| 263 | /* Not a full tcp header? */ |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 264 | th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph); |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 265 | if (th == NULL) |
| 266 | return NF_ACCEPT; |
| 267 | |
| 268 | /* No data? */ |
| 269 | dataoff = protoff + th->doff*4; |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 270 | if (dataoff >= skb->len) |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 271 | return NF_ACCEPT; |
| 272 | |
| 273 | spin_lock_bh(&irc_buffer_lock); |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 274 | ib_ptr = skb_header_pointer(skb, dataoff, skb->len - dataoff, |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 275 | irc_buffer); |
| 276 | BUG_ON(ib_ptr == NULL); |
| 277 | |
| 278 | data = ib_ptr; |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 279 | data_limit = ib_ptr + skb->len - dataoff; |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 280 | |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 281 | /* If packet is coming from IRC server |
| 282 | * parse the packet for different type of |
| 283 | * messages (MOTD,NICK etc) and process |
| 284 | * accordingly |
| 285 | */ |
| 286 | if (dir == IP_CT_DIR_REPLY) { |
| 287 | /* strlen("NICK xxxxxx") |
| 288 | * 5+strlen("xxxxxx")=1 (minimum length of nickname) |
| 289 | */ |
| 290 | |
| 291 | while (data < data_limit - 6) { |
| 292 | if (memcmp(data, " MOTD ", 6)) { |
| 293 | data++; |
| 294 | continue; |
| 295 | } |
| 296 | /* MOTD message signifies successful |
| 297 | * registration with server |
| 298 | */ |
| 299 | tuple = &ct->tuplehash[!dir].tuple; |
| 300 | temp = search_client_by_ip(tuple); |
| 301 | if (temp && !temp->conn_to_server) |
| 302 | temp->conn_to_server = true; |
| 303 | ret = NF_ACCEPT; |
| 304 | goto out; |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 305 | } |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 306 | |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 307 | /* strlen("NICK :xxxxxx") |
| 308 | * 6+strlen("xxxxxx")=1 (minimum length of nickname) |
| 309 | * Parsing the server reply to get nickname |
| 310 | * of the client |
| 311 | */ |
| 312 | data = ib_ptr; |
| 313 | data_limit = ib_ptr + skb->len - dataoff; |
| 314 | while (data < data_limit - (6 + MINLENNICK)) { |
| 315 | if (memcmp(data, "NICK :", 6)) { |
| 316 | data++; |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 317 | continue; |
| 318 | } |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 319 | data += 6; |
| 320 | nick_end = data; |
| 321 | i = 0; |
| 322 | while ((*nick_end != 0x0d) && |
| 323 | (*(nick_end + 1) != '\n')) { |
| 324 | nick_end++; |
| 325 | i++; |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 326 | } |
| 327 | tuple = &ct->tuplehash[!dir].tuple; |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 328 | temp = search_client_by_ip(tuple); |
| 329 | if (temp && temp->nickname) { |
| 330 | kfree(temp->nickname); |
| 331 | temp->nickname = kmalloc(i, GFP_ATOMIC); |
| 332 | if (temp->nickname) { |
| 333 | temp->nickname_len = i; |
| 334 | memcpy(temp->nickname, data, |
| 335 | temp->nickname_len); |
| 336 | temp->conn_to_server = true; |
| 337 | } else { |
| 338 | list_del(&temp->ptr); |
| 339 | no_of_clients--; |
| 340 | kfree(temp); |
| 341 | ret = NF_ACCEPT; |
| 342 | } |
Pablo Neira Ayuso | b20ab9cc | 2013-02-10 18:56:56 +0100 | [diff] [blame] | 343 | } |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 344 | /*NICK during registration*/ |
| 345 | ret = NF_ACCEPT; |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 346 | goto out; |
| 347 | } |
| 348 | } |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 349 | |
| 350 | else{ |
| 351 | /*Parsing NICK command from client to create an entry |
| 352 | * strlen("NICK xxxxxx") |
| 353 | * 5+strlen("xxxxxx")=1 (minimum length of nickname) |
| 354 | */ |
| 355 | data = ib_ptr; |
| 356 | data_limit = ib_ptr + skb->len - dataoff; |
| 357 | while (data < data_limit - (5 + MINLENNICK)) { |
| 358 | if (memcmp(data, "NICK ", 5)) { |
| 359 | data++; |
| 360 | continue; |
| 361 | } |
| 362 | data += 5; |
| 363 | ret = handle_nickname(ct, dir, data); |
| 364 | goto out; |
| 365 | } |
| 366 | |
| 367 | data = ib_ptr; |
| 368 | while (data < data_limit - 6) { |
| 369 | if (memcmp(data, "QUIT :", 6)) { |
| 370 | data++; |
| 371 | continue; |
| 372 | } |
| 373 | /* Parsing QUIT to free the list entry |
| 374 | */ |
| 375 | tuple = &ct->tuplehash[dir].tuple; |
| 376 | temp = search_client_by_ip(tuple); |
| 377 | if (temp) { |
| 378 | list_del(&temp->ptr); |
| 379 | no_of_clients--; |
| 380 | kfree(temp->nickname); |
| 381 | kfree(temp); |
| 382 | } |
| 383 | ret = NF_ACCEPT; |
| 384 | goto out; |
| 385 | } |
| 386 | /* strlen("\1DCC SENT t AAAAAAAA P\1\n")=24 |
| 387 | * 5+MINMATCHLEN+strlen("t AAAAAAAA P\1\n")=14 |
| 388 | */ |
| 389 | data = ib_ptr; |
| 390 | while (data < data_limit - (19 + MINMATCHLEN)) { |
| 391 | if (memcmp(data, "\1DCC ", 5)) { |
| 392 | data++; |
| 393 | continue; |
| 394 | } |
| 395 | data += 5; |
| 396 | /* we have at least (19+MINMATCHLEN)-5 |
| 397 | *bytes valid data left |
| 398 | */ |
| 399 | iph = ip_hdr(skb); |
| 400 | pr_debug("DCC found in master %pI4:%u %pI4:%u\n", |
| 401 | &iph->saddr, ntohs(th->source), |
| 402 | &iph->daddr, ntohs(th->dest)); |
| 403 | |
| 404 | for (i = 0; i < ARRAY_SIZE(dccprotos); i++) { |
| 405 | if (memcmp(data, dccprotos[i], |
| 406 | strlen(dccprotos[i]))) { |
| 407 | /* no match */ |
| 408 | continue; |
| 409 | } |
| 410 | data += strlen(dccprotos[i]); |
| 411 | pr_debug("DCC %s detected\n", dccprotos[i]); |
| 412 | |
| 413 | /* we have at least |
| 414 | * (19+MINMATCHLEN)-5-dccprotos[i].matchlen |
| 415 | *bytes valid data left (== 14/13 bytes) |
| 416 | */ |
| 417 | if (parse_dcc(data, data_limit, &dcc_ip, |
| 418 | &dcc_port, &addr_beg_p, |
| 419 | &addr_end_p)) { |
| 420 | pr_debug("unable to parse dcc command\n"); |
| 421 | continue; |
| 422 | } |
| 423 | |
| 424 | pr_debug("DCC bound ip/port: %pI4:%u\n", |
| 425 | &dcc_ip, dcc_port); |
| 426 | |
| 427 | /* dcc_ip can be the internal OR |
| 428 | *external (NAT'ed) IP |
| 429 | */ |
| 430 | tuple = &ct->tuplehash[dir].tuple; |
| 431 | if (tuple->src.u3.ip != dcc_ip && |
| 432 | tuple->dst.u3.ip != dcc_ip) { |
| 433 | net_warn_ratelimited("Forged DCC command from %pI4: %pI4:%u\n", |
| 434 | &tuple->src.u3.ip, |
| 435 | &dcc_ip, dcc_port); |
| 436 | continue; |
| 437 | } |
| 438 | |
| 439 | exp = nf_ct_expect_alloc(ct); |
| 440 | if (!exp) { |
| 441 | nf_ct_helper_log(skb, ct, |
| 442 | "cannot alloc expectation"); |
| 443 | ret = NF_DROP; |
| 444 | goto out; |
| 445 | } |
| 446 | tuple = &ct->tuplehash[!dir].tuple; |
| 447 | port = htons(dcc_port); |
| 448 | nf_ct_expect_init(exp, |
| 449 | NF_CT_EXPECT_CLASS_DEFAULT, |
| 450 | tuple->src.l3num, |
| 451 | NULL, &tuple->dst.u3, |
| 452 | IPPROTO_TCP, NULL, &port); |
| 453 | |
| 454 | nf_nat_irc = rcu_dereference(nf_nat_irc_hook); |
| 455 | |
| 456 | tuple = &ct->tuplehash[dir].tuple; |
| 457 | for_print = ib_ptr; |
| 458 | /* strlen("PRIVMSG xxxx :\1DCC |
| 459 | *SENT t AAAAAAAA P\1\n")=26 |
| 460 | * 8+strlen(xxxx) = 1(min length)+7+ |
| 461 | *MINMATCHLEN+strlen("t AAAAAAAA P\1\n")=14 |
| 462 | *Parsing DCC command to get client name and |
| 463 | *check whether it is an internal client |
| 464 | */ |
| 465 | while (for_print < |
| 466 | data_limit - (25 + MINMATCHLEN)) { |
| 467 | if (memcmp(for_print, "PRIVMSG ", 8)) { |
| 468 | for_print++; |
| 469 | continue; |
| 470 | } |
| 471 | for_print += 8; |
| 472 | mangle = mangle_ip(ct, |
| 473 | dir, for_print); |
| 474 | break; |
| 475 | } |
| 476 | if (mangle && |
| 477 | nf_nat_irc && |
| 478 | ct->status & IPS_NAT_MASK) |
| 479 | ret = nf_nat_irc(skb, ctinfo, |
| 480 | protoff, |
| 481 | addr_beg_p - ib_ptr, |
| 482 | addr_end_p |
| 483 | - addr_beg_p, |
| 484 | exp); |
| 485 | |
| 486 | else if (mangle && |
| 487 | nf_ct_expect_related(exp) |
| 488 | != 0) { |
| 489 | nf_ct_helper_log(skb, ct, |
| 490 | "cannot add expectation"); |
| 491 | ret = NF_DROP; |
| 492 | } |
| 493 | nf_ct_expect_put(exp); |
| 494 | goto out; |
| 495 | } |
| 496 | } |
| 497 | } |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 498 | out: |
| 499 | spin_unlock_bh(&irc_buffer_lock); |
| 500 | return ret; |
| 501 | } |
| 502 | |
| 503 | static struct nf_conntrack_helper irc[MAX_PORTS] __read_mostly; |
Patrick McHardy | 6002f266 | 2008-03-25 20:09:15 -0700 | [diff] [blame] | 504 | static struct nf_conntrack_expect_policy irc_exp_policy; |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 505 | |
| 506 | static void nf_conntrack_irc_fini(void); |
| 507 | |
| 508 | static int __init nf_conntrack_irc_init(void) |
| 509 | { |
| 510 | int i, ret; |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 511 | |
| 512 | if (max_dcc_channels < 1) { |
Pablo Neira Ayuso | ad6d950 | 2016-01-03 22:41:24 +0100 | [diff] [blame] | 513 | pr_err("max_dcc_channels must not be zero\n"); |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 514 | return -EINVAL; |
| 515 | } |
| 516 | |
Patrick McHardy | 6002f266 | 2008-03-25 20:09:15 -0700 | [diff] [blame] | 517 | irc_exp_policy.max_expected = max_dcc_channels; |
| 518 | irc_exp_policy.timeout = dcc_timeout; |
| 519 | |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 520 | irc_buffer = kmalloc(65536, GFP_KERNEL); |
| 521 | if (!irc_buffer) |
| 522 | return -ENOMEM; |
| 523 | |
| 524 | /* If no port given, default to standard irc port */ |
| 525 | if (ports_c == 0) |
| 526 | ports[ports_c++] = IRC_PORT; |
| 527 | |
| 528 | for (i = 0; i < ports_c; i++) { |
Gao Feng | 82de0be | 2016-07-18 11:39:23 +0800 | [diff] [blame] | 529 | nf_ct_helper_init(&irc[i], AF_INET, IPPROTO_TCP, "irc", |
| 530 | IRC_PORT, ports[i], i, &irc_exp_policy, |
| 531 | 0, 0, help, NULL, THIS_MODULE); |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 532 | } |
Gao Feng | 82de0be | 2016-07-18 11:39:23 +0800 | [diff] [blame] | 533 | |
| 534 | ret = nf_conntrack_helpers_register(&irc[0], ports_c); |
| 535 | if (ret) { |
| 536 | pr_err("failed to register helpers\n"); |
| 537 | kfree(irc_buffer); |
| 538 | return ret; |
| 539 | } |
Ravinder Konka | 2646eb6 | 2015-04-14 21:50:08 +0530 | [diff] [blame] | 540 | no_of_clients = 0; |
| 541 | INIT_LIST_HEAD(&client_list.ptr); |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 542 | return 0; |
| 543 | } |
| 544 | |
| 545 | /* This function is intentionally _NOT_ defined as __exit, because |
| 546 | * it is needed by the init function */ |
| 547 | static void nf_conntrack_irc_fini(void) |
| 548 | { |
Gao Feng | 82de0be | 2016-07-18 11:39:23 +0800 | [diff] [blame] | 549 | nf_conntrack_helpers_unregister(irc, ports_c); |
Patrick McHardy | 869f37d | 2006-12-02 22:09:06 -0800 | [diff] [blame] | 550 | kfree(irc_buffer); |
| 551 | } |
| 552 | |
| 553 | module_init(nf_conntrack_irc_init); |
| 554 | module_exit(nf_conntrack_irc_fini); |