Pablo Neira Ayuso | 83e96d4 | 2014-06-19 20:47:14 +0200 | [diff] [blame] | 1 | /* (C) 1999-2001 Paul `Rusty' Russell |
| 2 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License version 2 as |
| 6 | * published by the Free Software Foundation. |
| 7 | */ |
Marcelo Leitner | 8ac2bde | 2014-10-29 10:51:13 -0200 | [diff] [blame^] | 8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
Pablo Neira Ayuso | 83e96d4 | 2014-06-19 20:47:14 +0200 | [diff] [blame] | 9 | |
| 10 | #include <linux/module.h> |
| 11 | #include <linux/spinlock.h> |
| 12 | #include <linux/skbuff.h> |
| 13 | #include <linux/if_arp.h> |
| 14 | #include <linux/ip.h> |
| 15 | #include <net/ipv6.h> |
| 16 | #include <net/icmp.h> |
| 17 | #include <net/udp.h> |
| 18 | #include <net/tcp.h> |
| 19 | #include <net/route.h> |
| 20 | |
| 21 | #include <linux/netfilter.h> |
| 22 | #include <linux/netfilter/xt_LOG.h> |
| 23 | #include <net/netfilter/nf_log.h> |
| 24 | |
| 25 | static struct nf_loginfo default_loginfo = { |
| 26 | .type = NF_LOG_TYPE_LOG, |
| 27 | .u = { |
| 28 | .log = { |
| 29 | .level = 5, |
| 30 | .logflags = NF_LOG_MASK, |
| 31 | }, |
| 32 | }, |
| 33 | }; |
| 34 | |
| 35 | /* One level of recursion won't kill us */ |
| 36 | static void dump_ipv4_packet(struct nf_log_buf *m, |
| 37 | const struct nf_loginfo *info, |
| 38 | const struct sk_buff *skb, unsigned int iphoff) |
| 39 | { |
| 40 | struct iphdr _iph; |
| 41 | const struct iphdr *ih; |
| 42 | unsigned int logflags; |
| 43 | |
| 44 | if (info->type == NF_LOG_TYPE_LOG) |
| 45 | logflags = info->u.log.logflags; |
| 46 | else |
| 47 | logflags = NF_LOG_MASK; |
| 48 | |
| 49 | ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph); |
| 50 | if (ih == NULL) { |
| 51 | nf_log_buf_add(m, "TRUNCATED"); |
| 52 | return; |
| 53 | } |
| 54 | |
| 55 | /* Important fields: |
| 56 | * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */ |
| 57 | /* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */ |
| 58 | nf_log_buf_add(m, "SRC=%pI4 DST=%pI4 ", &ih->saddr, &ih->daddr); |
| 59 | |
| 60 | /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */ |
| 61 | nf_log_buf_add(m, "LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ", |
| 62 | ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK, |
| 63 | ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id)); |
| 64 | |
| 65 | /* Max length: 6 "CE DF MF " */ |
| 66 | if (ntohs(ih->frag_off) & IP_CE) |
| 67 | nf_log_buf_add(m, "CE "); |
| 68 | if (ntohs(ih->frag_off) & IP_DF) |
| 69 | nf_log_buf_add(m, "DF "); |
| 70 | if (ntohs(ih->frag_off) & IP_MF) |
| 71 | nf_log_buf_add(m, "MF "); |
| 72 | |
| 73 | /* Max length: 11 "FRAG:65535 " */ |
| 74 | if (ntohs(ih->frag_off) & IP_OFFSET) |
| 75 | nf_log_buf_add(m, "FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET); |
| 76 | |
| 77 | if ((logflags & XT_LOG_IPOPT) && |
| 78 | ih->ihl * 4 > sizeof(struct iphdr)) { |
| 79 | const unsigned char *op; |
| 80 | unsigned char _opt[4 * 15 - sizeof(struct iphdr)]; |
| 81 | unsigned int i, optsize; |
| 82 | |
| 83 | optsize = ih->ihl * 4 - sizeof(struct iphdr); |
| 84 | op = skb_header_pointer(skb, iphoff+sizeof(_iph), |
| 85 | optsize, _opt); |
| 86 | if (op == NULL) { |
| 87 | nf_log_buf_add(m, "TRUNCATED"); |
| 88 | return; |
| 89 | } |
| 90 | |
| 91 | /* Max length: 127 "OPT (" 15*4*2chars ") " */ |
| 92 | nf_log_buf_add(m, "OPT ("); |
| 93 | for (i = 0; i < optsize; i++) |
| 94 | nf_log_buf_add(m, "%02X", op[i]); |
| 95 | nf_log_buf_add(m, ") "); |
| 96 | } |
| 97 | |
| 98 | switch (ih->protocol) { |
| 99 | case IPPROTO_TCP: |
| 100 | if (nf_log_dump_tcp_header(m, skb, ih->protocol, |
| 101 | ntohs(ih->frag_off) & IP_OFFSET, |
| 102 | iphoff+ih->ihl*4, logflags)) |
| 103 | return; |
| 104 | break; |
| 105 | case IPPROTO_UDP: |
| 106 | case IPPROTO_UDPLITE: |
| 107 | if (nf_log_dump_udp_header(m, skb, ih->protocol, |
| 108 | ntohs(ih->frag_off) & IP_OFFSET, |
| 109 | iphoff+ih->ihl*4)) |
| 110 | return; |
| 111 | break; |
| 112 | case IPPROTO_ICMP: { |
| 113 | struct icmphdr _icmph; |
| 114 | const struct icmphdr *ich; |
| 115 | static const size_t required_len[NR_ICMP_TYPES+1] |
| 116 | = { [ICMP_ECHOREPLY] = 4, |
| 117 | [ICMP_DEST_UNREACH] |
| 118 | = 8 + sizeof(struct iphdr), |
| 119 | [ICMP_SOURCE_QUENCH] |
| 120 | = 8 + sizeof(struct iphdr), |
| 121 | [ICMP_REDIRECT] |
| 122 | = 8 + sizeof(struct iphdr), |
| 123 | [ICMP_ECHO] = 4, |
| 124 | [ICMP_TIME_EXCEEDED] |
| 125 | = 8 + sizeof(struct iphdr), |
| 126 | [ICMP_PARAMETERPROB] |
| 127 | = 8 + sizeof(struct iphdr), |
| 128 | [ICMP_TIMESTAMP] = 20, |
| 129 | [ICMP_TIMESTAMPREPLY] = 20, |
| 130 | [ICMP_ADDRESS] = 12, |
| 131 | [ICMP_ADDRESSREPLY] = 12 }; |
| 132 | |
| 133 | /* Max length: 11 "PROTO=ICMP " */ |
| 134 | nf_log_buf_add(m, "PROTO=ICMP "); |
| 135 | |
| 136 | if (ntohs(ih->frag_off) & IP_OFFSET) |
| 137 | break; |
| 138 | |
| 139 | /* Max length: 25 "INCOMPLETE [65535 bytes] " */ |
| 140 | ich = skb_header_pointer(skb, iphoff + ih->ihl * 4, |
| 141 | sizeof(_icmph), &_icmph); |
| 142 | if (ich == NULL) { |
| 143 | nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", |
| 144 | skb->len - iphoff - ih->ihl*4); |
| 145 | break; |
| 146 | } |
| 147 | |
| 148 | /* Max length: 18 "TYPE=255 CODE=255 " */ |
| 149 | nf_log_buf_add(m, "TYPE=%u CODE=%u ", ich->type, ich->code); |
| 150 | |
| 151 | /* Max length: 25 "INCOMPLETE [65535 bytes] " */ |
| 152 | if (ich->type <= NR_ICMP_TYPES && |
| 153 | required_len[ich->type] && |
| 154 | skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) { |
| 155 | nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", |
| 156 | skb->len - iphoff - ih->ihl*4); |
| 157 | break; |
| 158 | } |
| 159 | |
| 160 | switch (ich->type) { |
| 161 | case ICMP_ECHOREPLY: |
| 162 | case ICMP_ECHO: |
| 163 | /* Max length: 19 "ID=65535 SEQ=65535 " */ |
| 164 | nf_log_buf_add(m, "ID=%u SEQ=%u ", |
| 165 | ntohs(ich->un.echo.id), |
| 166 | ntohs(ich->un.echo.sequence)); |
| 167 | break; |
| 168 | |
| 169 | case ICMP_PARAMETERPROB: |
| 170 | /* Max length: 14 "PARAMETER=255 " */ |
| 171 | nf_log_buf_add(m, "PARAMETER=%u ", |
| 172 | ntohl(ich->un.gateway) >> 24); |
| 173 | break; |
| 174 | case ICMP_REDIRECT: |
| 175 | /* Max length: 24 "GATEWAY=255.255.255.255 " */ |
| 176 | nf_log_buf_add(m, "GATEWAY=%pI4 ", &ich->un.gateway); |
| 177 | /* Fall through */ |
| 178 | case ICMP_DEST_UNREACH: |
| 179 | case ICMP_SOURCE_QUENCH: |
| 180 | case ICMP_TIME_EXCEEDED: |
| 181 | /* Max length: 3+maxlen */ |
| 182 | if (!iphoff) { /* Only recurse once. */ |
| 183 | nf_log_buf_add(m, "["); |
| 184 | dump_ipv4_packet(m, info, skb, |
| 185 | iphoff + ih->ihl*4+sizeof(_icmph)); |
| 186 | nf_log_buf_add(m, "] "); |
| 187 | } |
| 188 | |
| 189 | /* Max length: 10 "MTU=65535 " */ |
| 190 | if (ich->type == ICMP_DEST_UNREACH && |
| 191 | ich->code == ICMP_FRAG_NEEDED) { |
| 192 | nf_log_buf_add(m, "MTU=%u ", |
| 193 | ntohs(ich->un.frag.mtu)); |
| 194 | } |
| 195 | } |
| 196 | break; |
| 197 | } |
| 198 | /* Max Length */ |
| 199 | case IPPROTO_AH: { |
| 200 | struct ip_auth_hdr _ahdr; |
| 201 | const struct ip_auth_hdr *ah; |
| 202 | |
| 203 | if (ntohs(ih->frag_off) & IP_OFFSET) |
| 204 | break; |
| 205 | |
| 206 | /* Max length: 9 "PROTO=AH " */ |
| 207 | nf_log_buf_add(m, "PROTO=AH "); |
| 208 | |
| 209 | /* Max length: 25 "INCOMPLETE [65535 bytes] " */ |
| 210 | ah = skb_header_pointer(skb, iphoff+ih->ihl*4, |
| 211 | sizeof(_ahdr), &_ahdr); |
| 212 | if (ah == NULL) { |
| 213 | nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", |
| 214 | skb->len - iphoff - ih->ihl*4); |
| 215 | break; |
| 216 | } |
| 217 | |
| 218 | /* Length: 15 "SPI=0xF1234567 " */ |
| 219 | nf_log_buf_add(m, "SPI=0x%x ", ntohl(ah->spi)); |
| 220 | break; |
| 221 | } |
| 222 | case IPPROTO_ESP: { |
| 223 | struct ip_esp_hdr _esph; |
| 224 | const struct ip_esp_hdr *eh; |
| 225 | |
| 226 | /* Max length: 10 "PROTO=ESP " */ |
| 227 | nf_log_buf_add(m, "PROTO=ESP "); |
| 228 | |
| 229 | if (ntohs(ih->frag_off) & IP_OFFSET) |
| 230 | break; |
| 231 | |
| 232 | /* Max length: 25 "INCOMPLETE [65535 bytes] " */ |
| 233 | eh = skb_header_pointer(skb, iphoff+ih->ihl*4, |
| 234 | sizeof(_esph), &_esph); |
| 235 | if (eh == NULL) { |
| 236 | nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", |
| 237 | skb->len - iphoff - ih->ihl*4); |
| 238 | break; |
| 239 | } |
| 240 | |
| 241 | /* Length: 15 "SPI=0xF1234567 " */ |
| 242 | nf_log_buf_add(m, "SPI=0x%x ", ntohl(eh->spi)); |
| 243 | break; |
| 244 | } |
| 245 | /* Max length: 10 "PROTO 255 " */ |
| 246 | default: |
| 247 | nf_log_buf_add(m, "PROTO=%u ", ih->protocol); |
| 248 | } |
| 249 | |
| 250 | /* Max length: 15 "UID=4294967295 " */ |
| 251 | if ((logflags & XT_LOG_UID) && !iphoff) |
| 252 | nf_log_dump_sk_uid_gid(m, skb->sk); |
| 253 | |
| 254 | /* Max length: 16 "MARK=0xFFFFFFFF " */ |
| 255 | if (!iphoff && skb->mark) |
| 256 | nf_log_buf_add(m, "MARK=0x%x ", skb->mark); |
| 257 | |
| 258 | /* Proto Max log string length */ |
| 259 | /* IP: 40+46+6+11+127 = 230 */ |
| 260 | /* TCP: 10+max(25,20+30+13+9+32+11+127) = 252 */ |
| 261 | /* UDP: 10+max(25,20) = 35 */ |
| 262 | /* UDPLITE: 14+max(25,20) = 39 */ |
| 263 | /* ICMP: 11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */ |
| 264 | /* ESP: 10+max(25)+15 = 50 */ |
| 265 | /* AH: 9+max(25)+15 = 49 */ |
| 266 | /* unknown: 10 */ |
| 267 | |
| 268 | /* (ICMP allows recursion one level deep) */ |
| 269 | /* maxlen = IP + ICMP + IP + max(TCP,UDP,ICMP,unknown) */ |
| 270 | /* maxlen = 230+ 91 + 230 + 252 = 803 */ |
| 271 | } |
| 272 | |
| 273 | static void dump_ipv4_mac_header(struct nf_log_buf *m, |
| 274 | const struct nf_loginfo *info, |
| 275 | const struct sk_buff *skb) |
| 276 | { |
| 277 | struct net_device *dev = skb->dev; |
| 278 | unsigned int logflags = 0; |
| 279 | |
| 280 | if (info->type == NF_LOG_TYPE_LOG) |
| 281 | logflags = info->u.log.logflags; |
| 282 | |
| 283 | if (!(logflags & XT_LOG_MACDECODE)) |
| 284 | goto fallback; |
| 285 | |
| 286 | switch (dev->type) { |
| 287 | case ARPHRD_ETHER: |
| 288 | nf_log_buf_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ", |
| 289 | eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest, |
| 290 | ntohs(eth_hdr(skb)->h_proto)); |
| 291 | return; |
| 292 | default: |
| 293 | break; |
| 294 | } |
| 295 | |
| 296 | fallback: |
| 297 | nf_log_buf_add(m, "MAC="); |
| 298 | if (dev->hard_header_len && |
| 299 | skb->mac_header != skb->network_header) { |
| 300 | const unsigned char *p = skb_mac_header(skb); |
| 301 | unsigned int i; |
| 302 | |
| 303 | nf_log_buf_add(m, "%02x", *p++); |
| 304 | for (i = 1; i < dev->hard_header_len; i++, p++) |
| 305 | nf_log_buf_add(m, ":%02x", *p); |
| 306 | } |
| 307 | nf_log_buf_add(m, " "); |
| 308 | } |
| 309 | |
Pablo Neira Ayuso | fab4085 | 2014-06-18 19:38:25 +0200 | [diff] [blame] | 310 | static void nf_log_ip_packet(struct net *net, u_int8_t pf, |
| 311 | unsigned int hooknum, const struct sk_buff *skb, |
| 312 | const struct net_device *in, |
| 313 | const struct net_device *out, |
| 314 | const struct nf_loginfo *loginfo, |
| 315 | const char *prefix) |
Pablo Neira Ayuso | 83e96d4 | 2014-06-19 20:47:14 +0200 | [diff] [blame] | 316 | { |
| 317 | struct nf_log_buf *m; |
| 318 | |
| 319 | /* FIXME: Disabled from containers until syslog ns is supported */ |
| 320 | if (!net_eq(net, &init_net)) |
| 321 | return; |
| 322 | |
| 323 | m = nf_log_buf_open(); |
| 324 | |
| 325 | if (!loginfo) |
| 326 | loginfo = &default_loginfo; |
| 327 | |
| 328 | nf_log_dump_packet_common(m, pf, hooknum, skb, in, |
| 329 | out, loginfo, prefix); |
| 330 | |
| 331 | if (in != NULL) |
| 332 | dump_ipv4_mac_header(m, loginfo, skb); |
| 333 | |
| 334 | dump_ipv4_packet(m, loginfo, skb, 0); |
| 335 | |
| 336 | nf_log_buf_close(m); |
| 337 | } |
Pablo Neira Ayuso | 83e96d4 | 2014-06-19 20:47:14 +0200 | [diff] [blame] | 338 | |
| 339 | static struct nf_logger nf_ip_logger __read_mostly = { |
| 340 | .name = "nf_log_ipv4", |
| 341 | .type = NF_LOG_TYPE_LOG, |
| 342 | .logfn = nf_log_ip_packet, |
| 343 | .me = THIS_MODULE, |
| 344 | }; |
| 345 | |
| 346 | static int __net_init nf_log_ipv4_net_init(struct net *net) |
| 347 | { |
| 348 | nf_log_set(net, NFPROTO_IPV4, &nf_ip_logger); |
| 349 | return 0; |
| 350 | } |
| 351 | |
| 352 | static void __net_exit nf_log_ipv4_net_exit(struct net *net) |
| 353 | { |
| 354 | nf_log_unset(net, &nf_ip_logger); |
| 355 | } |
| 356 | |
| 357 | static struct pernet_operations nf_log_ipv4_net_ops = { |
| 358 | .init = nf_log_ipv4_net_init, |
| 359 | .exit = nf_log_ipv4_net_exit, |
| 360 | }; |
| 361 | |
| 362 | static int __init nf_log_ipv4_init(void) |
| 363 | { |
| 364 | int ret; |
| 365 | |
| 366 | ret = register_pernet_subsys(&nf_log_ipv4_net_ops); |
| 367 | if (ret < 0) |
| 368 | return ret; |
| 369 | |
Marcelo Leitner | 8ac2bde | 2014-10-29 10:51:13 -0200 | [diff] [blame^] | 370 | ret = nf_log_register(NFPROTO_IPV4, &nf_ip_logger); |
| 371 | if (ret < 0) { |
| 372 | pr_err("failed to register logger\n"); |
| 373 | goto err1; |
| 374 | } |
| 375 | |
Pablo Neira Ayuso | 83e96d4 | 2014-06-19 20:47:14 +0200 | [diff] [blame] | 376 | return 0; |
Marcelo Leitner | 8ac2bde | 2014-10-29 10:51:13 -0200 | [diff] [blame^] | 377 | |
| 378 | err1: |
| 379 | unregister_pernet_subsys(&nf_log_ipv4_net_ops); |
| 380 | return ret; |
Pablo Neira Ayuso | 83e96d4 | 2014-06-19 20:47:14 +0200 | [diff] [blame] | 381 | } |
| 382 | |
| 383 | static void __exit nf_log_ipv4_exit(void) |
| 384 | { |
| 385 | unregister_pernet_subsys(&nf_log_ipv4_net_ops); |
| 386 | nf_log_unregister(&nf_ip_logger); |
| 387 | } |
| 388 | |
| 389 | module_init(nf_log_ipv4_init); |
| 390 | module_exit(nf_log_ipv4_exit); |
| 391 | |
| 392 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); |
| 393 | MODULE_DESCRIPTION("Netfilter IPv4 packet logging"); |
| 394 | MODULE_LICENSE("GPL"); |
Pablo Neira Ayuso | fab4085 | 2014-06-18 19:38:25 +0200 | [diff] [blame] | 395 | MODULE_ALIAS_NF_LOGGER(AF_INET, 0); |