1 /* (C) 1999-2001 Paul `Rusty' Russell 2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> 3 * (C) 2006-2012 Patrick McHardy <kaber@trash.net> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 */ 9 10 #include <linux/types.h> 11 #include <linux/timer.h> 12 #include <linux/module.h> 13 #include <linux/udp.h> 14 #include <linux/seq_file.h> 15 #include <linux/skbuff.h> 16 #include <linux/ipv6.h> 17 #include <net/ip6_checksum.h> 18 #include <net/checksum.h> 19 20 #include <linux/netfilter.h> 21 #include <linux/netfilter_ipv4.h> 22 #include <linux/netfilter_ipv6.h> 23 #include <net/netfilter/nf_conntrack_l4proto.h> 24 #include <net/netfilter/nf_conntrack_ecache.h> 25 #include <net/netfilter/nf_log.h> 26 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h> 27 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h> 28 29 static const unsigned int udp_timeouts[UDP_CT_MAX] = { 30 [UDP_CT_UNREPLIED] = 30*HZ, 31 [UDP_CT_REPLIED] = 180*HZ, 32 }; 33 34 static inline struct nf_udp_net *udp_pernet(struct net *net) 35 { 36 return &net->ct.nf_ct_proto.udp; 37 } 38 39 static bool udp_pkt_to_tuple(const struct sk_buff *skb, 40 unsigned int dataoff, 41 struct net *net, 42 struct nf_conntrack_tuple *tuple) 43 { 44 const struct udphdr *hp; 45 struct udphdr _hdr; 46 47 /* Actually only need first 4 bytes to get ports. */ 48 hp = skb_header_pointer(skb, dataoff, 4, &_hdr); 49 if (hp == NULL) 50 return false; 51 52 tuple->src.u.udp.port = hp->source; 53 tuple->dst.u.udp.port = hp->dest; 54 55 return true; 56 } 57 58 static bool udp_invert_tuple(struct nf_conntrack_tuple *tuple, 59 const struct nf_conntrack_tuple *orig) 60 { 61 tuple->src.u.udp.port = orig->dst.u.udp.port; 62 tuple->dst.u.udp.port = orig->src.u.udp.port; 63 return true; 64 } 65 66 static unsigned int *udp_get_timeouts(struct net *net) 67 { 68 return udp_pernet(net)->timeouts; 69 } 70 71 /* Returns verdict for packet, and may modify conntracktype */ 72 static int udp_packet(struct nf_conn *ct, 73 const struct sk_buff *skb, 74 unsigned int dataoff, 75 enum ip_conntrack_info ctinfo, 76 unsigned int *timeouts) 77 { 78 /* If we've seen traffic both ways, this is some kind of UDP 79 stream. Extend timeout. */ 80 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 81 nf_ct_refresh_acct(ct, ctinfo, skb, 82 timeouts[UDP_CT_REPLIED]); 83 /* Also, more likely to be important, and not a probe */ 84 if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status)) 85 nf_conntrack_event_cache(IPCT_ASSURED, ct); 86 } else { 87 nf_ct_refresh_acct(ct, ctinfo, skb, 88 timeouts[UDP_CT_UNREPLIED]); 89 } 90 return NF_ACCEPT; 91 } 92 93 /* Called when a new connection for this protocol found. */ 94 static bool udp_new(struct nf_conn *ct, const struct sk_buff *skb, 95 unsigned int dataoff, unsigned int *timeouts) 96 { 97 return true; 98 } 99 100 #ifdef CONFIG_NF_CT_PROTO_UDPLITE 101 static void udplite_error_log(const struct sk_buff *skb, struct net *net, 102 u8 pf, const char *msg) 103 { 104 nf_l4proto_log_invalid(skb, net, pf, IPPROTO_UDPLITE, "%s", msg); 105 } 106 107 static int udplite_error(struct net *net, struct nf_conn *tmpl, 108 struct sk_buff *skb, 109 unsigned int dataoff, 110 u8 pf, unsigned int hooknum) 111 { 112 unsigned int udplen = skb->len - dataoff; 113 const struct udphdr *hdr; 114 struct udphdr _hdr; 115 unsigned int cscov; 116 117 /* Header is too small? */ 118 hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); 119 if (!hdr) { 120 udplite_error_log(skb, net, pf, "short packet"); 121 return -NF_ACCEPT; 122 } 123 124 cscov = ntohs(hdr->len); 125 if (cscov == 0) { 126 cscov = udplen; 127 } else if (cscov < sizeof(*hdr) || cscov > udplen) { 128 udplite_error_log(skb, net, pf, "invalid checksum coverage"); 129 return -NF_ACCEPT; 130 } 131 132 /* UDPLITE mandates checksums */ 133 if (!hdr->check) { 134 udplite_error_log(skb, net, pf, "checksum missing"); 135 return -NF_ACCEPT; 136 } 137 138 /* Checksum invalid? Ignore. */ 139 if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING && 140 nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_UDP, 141 pf)) { 142 udplite_error_log(skb, net, pf, "bad checksum"); 143 return -NF_ACCEPT; 144 } 145 146 return NF_ACCEPT; 147 } 148 #endif 149 150 static void udp_error_log(const struct sk_buff *skb, struct net *net, 151 u8 pf, const char *msg) 152 { 153 nf_l4proto_log_invalid(skb, net, pf, IPPROTO_UDP, "%s", msg); 154 } 155 156 static int udp_error(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb, 157 unsigned int dataoff, 158 u_int8_t pf, 159 unsigned int hooknum) 160 { 161 unsigned int udplen = skb->len - dataoff; 162 const struct udphdr *hdr; 163 struct udphdr _hdr; 164 165 /* Header is too small? */ 166 hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); 167 if (hdr == NULL) { 168 udp_error_log(skb, net, pf, "short packet"); 169 return -NF_ACCEPT; 170 } 171 172 /* Truncated/malformed packets */ 173 if (ntohs(hdr->len) > udplen || ntohs(hdr->len) < sizeof(*hdr)) { 174 udp_error_log(skb, net, pf, "truncated/malformed packet"); 175 return -NF_ACCEPT; 176 } 177 178 /* Packet with no checksum */ 179 if (!hdr->check) 180 return NF_ACCEPT; 181 182 /* Checksum invalid? Ignore. 183 * We skip checking packets on the outgoing path 184 * because the checksum is assumed to be correct. 185 * FIXME: Source route IP option packets --RR */ 186 if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING && 187 nf_checksum(skb, hooknum, dataoff, IPPROTO_UDP, pf)) { 188 udp_error_log(skb, net, pf, "bad checksum"); 189 return -NF_ACCEPT; 190 } 191 192 return NF_ACCEPT; 193 } 194 195 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT) 196 197 #include <linux/netfilter/nfnetlink.h> 198 #include <linux/netfilter/nfnetlink_cttimeout.h> 199 200 static int udp_timeout_nlattr_to_obj(struct nlattr *tb[], 201 struct net *net, void *data) 202 { 203 unsigned int *timeouts = data; 204 struct nf_udp_net *un = udp_pernet(net); 205 206 /* set default timeouts for UDP. */ 207 timeouts[UDP_CT_UNREPLIED] = un->timeouts[UDP_CT_UNREPLIED]; 208 timeouts[UDP_CT_REPLIED] = un->timeouts[UDP_CT_REPLIED]; 209 210 if (tb[CTA_TIMEOUT_UDP_UNREPLIED]) { 211 timeouts[UDP_CT_UNREPLIED] = 212 ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_UNREPLIED])) * HZ; 213 } 214 if (tb[CTA_TIMEOUT_UDP_REPLIED]) { 215 timeouts[UDP_CT_REPLIED] = 216 ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDP_REPLIED])) * HZ; 217 } 218 return 0; 219 } 220 221 static int 222 udp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data) 223 { 224 const unsigned int *timeouts = data; 225 226 if (nla_put_be32(skb, CTA_TIMEOUT_UDP_UNREPLIED, 227 htonl(timeouts[UDP_CT_UNREPLIED] / HZ)) || 228 nla_put_be32(skb, CTA_TIMEOUT_UDP_REPLIED, 229 htonl(timeouts[UDP_CT_REPLIED] / HZ))) 230 goto nla_put_failure; 231 return 0; 232 233 nla_put_failure: 234 return -ENOSPC; 235 } 236 237 static const struct nla_policy 238 udp_timeout_nla_policy[CTA_TIMEOUT_UDP_MAX+1] = { 239 [CTA_TIMEOUT_UDP_UNREPLIED] = { .type = NLA_U32 }, 240 [CTA_TIMEOUT_UDP_REPLIED] = { .type = NLA_U32 }, 241 }; 242 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */ 243 244 #ifdef CONFIG_SYSCTL 245 static struct ctl_table udp_sysctl_table[] = { 246 { 247 .procname = "nf_conntrack_udp_timeout", 248 .maxlen = sizeof(unsigned int), 249 .mode = 0644, 250 .proc_handler = proc_dointvec_jiffies, 251 }, 252 { 253 .procname = "nf_conntrack_udp_timeout_stream", 254 .maxlen = sizeof(unsigned int), 255 .mode = 0644, 256 .proc_handler = proc_dointvec_jiffies, 257 }, 258 { } 259 }; 260 #endif /* CONFIG_SYSCTL */ 261 262 static int udp_kmemdup_sysctl_table(struct nf_proto_net *pn, 263 struct nf_udp_net *un) 264 { 265 #ifdef CONFIG_SYSCTL 266 if (pn->ctl_table) 267 return 0; 268 pn->ctl_table = kmemdup(udp_sysctl_table, 269 sizeof(udp_sysctl_table), 270 GFP_KERNEL); 271 if (!pn->ctl_table) 272 return -ENOMEM; 273 pn->ctl_table[0].data = &un->timeouts[UDP_CT_UNREPLIED]; 274 pn->ctl_table[1].data = &un->timeouts[UDP_CT_REPLIED]; 275 #endif 276 return 0; 277 } 278 279 static int udp_init_net(struct net *net, u_int16_t proto) 280 { 281 struct nf_udp_net *un = udp_pernet(net); 282 struct nf_proto_net *pn = &un->pn; 283 284 if (!pn->users) { 285 int i; 286 287 for (i = 0; i < UDP_CT_MAX; i++) 288 un->timeouts[i] = udp_timeouts[i]; 289 } 290 291 return udp_kmemdup_sysctl_table(pn, un); 292 } 293 294 static struct nf_proto_net *udp_get_net_proto(struct net *net) 295 { 296 return &net->ct.nf_ct_proto.udp.pn; 297 } 298 299 const struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4 = 300 { 301 .l3proto = PF_INET, 302 .l4proto = IPPROTO_UDP, 303 .allow_clash = true, 304 .pkt_to_tuple = udp_pkt_to_tuple, 305 .invert_tuple = udp_invert_tuple, 306 .packet = udp_packet, 307 .get_timeouts = udp_get_timeouts, 308 .new = udp_new, 309 .error = udp_error, 310 #if IS_ENABLED(CONFIG_NF_CT_NETLINK) 311 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, 312 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, 313 .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, 314 .nla_policy = nf_ct_port_nla_policy, 315 #endif 316 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT) 317 .ctnl_timeout = { 318 .nlattr_to_obj = udp_timeout_nlattr_to_obj, 319 .obj_to_nlattr = udp_timeout_obj_to_nlattr, 320 .nlattr_max = CTA_TIMEOUT_UDP_MAX, 321 .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX, 322 .nla_policy = udp_timeout_nla_policy, 323 }, 324 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */ 325 .init_net = udp_init_net, 326 .get_net_proto = udp_get_net_proto, 327 }; 328 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp4); 329 330 #ifdef CONFIG_NF_CT_PROTO_UDPLITE 331 const struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite4 = 332 { 333 .l3proto = PF_INET, 334 .l4proto = IPPROTO_UDPLITE, 335 .allow_clash = true, 336 .pkt_to_tuple = udp_pkt_to_tuple, 337 .invert_tuple = udp_invert_tuple, 338 .packet = udp_packet, 339 .get_timeouts = udp_get_timeouts, 340 .new = udp_new, 341 .error = udplite_error, 342 #if IS_ENABLED(CONFIG_NF_CT_NETLINK) 343 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, 344 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, 345 .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, 346 .nla_policy = nf_ct_port_nla_policy, 347 #endif 348 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT) 349 .ctnl_timeout = { 350 .nlattr_to_obj = udp_timeout_nlattr_to_obj, 351 .obj_to_nlattr = udp_timeout_obj_to_nlattr, 352 .nlattr_max = CTA_TIMEOUT_UDP_MAX, 353 .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX, 354 .nla_policy = udp_timeout_nla_policy, 355 }, 356 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */ 357 .init_net = udp_init_net, 358 .get_net_proto = udp_get_net_proto, 359 }; 360 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udplite4); 361 #endif 362 363 const struct nf_conntrack_l4proto nf_conntrack_l4proto_udp6 = 364 { 365 .l3proto = PF_INET6, 366 .l4proto = IPPROTO_UDP, 367 .allow_clash = true, 368 .pkt_to_tuple = udp_pkt_to_tuple, 369 .invert_tuple = udp_invert_tuple, 370 .packet = udp_packet, 371 .get_timeouts = udp_get_timeouts, 372 .new = udp_new, 373 .error = udp_error, 374 #if IS_ENABLED(CONFIG_NF_CT_NETLINK) 375 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, 376 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, 377 .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, 378 .nla_policy = nf_ct_port_nla_policy, 379 #endif 380 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT) 381 .ctnl_timeout = { 382 .nlattr_to_obj = udp_timeout_nlattr_to_obj, 383 .obj_to_nlattr = udp_timeout_obj_to_nlattr, 384 .nlattr_max = CTA_TIMEOUT_UDP_MAX, 385 .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX, 386 .nla_policy = udp_timeout_nla_policy, 387 }, 388 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */ 389 .init_net = udp_init_net, 390 .get_net_proto = udp_get_net_proto, 391 }; 392 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udp6); 393 394 #ifdef CONFIG_NF_CT_PROTO_UDPLITE 395 const struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite6 = 396 { 397 .l3proto = PF_INET6, 398 .l4proto = IPPROTO_UDPLITE, 399 .allow_clash = true, 400 .pkt_to_tuple = udp_pkt_to_tuple, 401 .invert_tuple = udp_invert_tuple, 402 .packet = udp_packet, 403 .get_timeouts = udp_get_timeouts, 404 .new = udp_new, 405 .error = udplite_error, 406 #if IS_ENABLED(CONFIG_NF_CT_NETLINK) 407 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, 408 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, 409 .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, 410 .nla_policy = nf_ct_port_nla_policy, 411 #endif 412 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT) 413 .ctnl_timeout = { 414 .nlattr_to_obj = udp_timeout_nlattr_to_obj, 415 .obj_to_nlattr = udp_timeout_obj_to_nlattr, 416 .nlattr_max = CTA_TIMEOUT_UDP_MAX, 417 .obj_size = sizeof(unsigned int) * CTA_TIMEOUT_UDP_MAX, 418 .nla_policy = udp_timeout_nla_policy, 419 }, 420 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */ 421 .init_net = udp_init_net, 422 .get_net_proto = udp_get_net_proto, 423 }; 424 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_udplite6); 425 #endif 426