net/ipv6/netfilter/nf_log_ipv6.c

   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  */
   8
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/if_arp.h>
  16 #include <linux/ip.h>
  17 #include <net/ipv6.h>
  18 #include <net/icmp.h>
  19 #include <net/udp.h>
  20 #include <net/tcp.h>
  21 #include <net/route.h>
  22
  23 #include <linux/netfilter.h>
  24 #include <linux/netfilter_ipv6/ip6_tables.h>
  25 #include <linux/netfilter/xt_LOG.h>
  26 #include <net/netfilter/nf_log.h>
  27
  28 static struct nf_loginfo default_loginfo = {
  29         .type   = NF_LOG_TYPE_LOG,
  30         .u = {
  31                 .log = {
  32                         .level    = LOGLEVEL_NOTICE,
  33                         .logflags = NF_LOG_MASK,
  34                 },
  35         },
  36 };
  37
  38 /* One level of recursion won't kill us */
  39 static void dump_ipv6_packet(struct nf_log_buf *m,
  40                              const struct nf_loginfo *info,
  41                              const struct sk_buff *skb, unsigned int ip6hoff,
  42                              int recurse)
  43 {
  44         u_int8_t currenthdr;
  45         int fragment;
  46         struct ipv6hdr _ip6h;
  47         const struct ipv6hdr *ih;
  48         unsigned int ptr;
  49         unsigned int hdrlen = 0;
  50         unsigned int logflags;
  51
  52         if (info->type == NF_LOG_TYPE_LOG)
  53                 logflags = info->u.log.logflags;
  54         else
  55                 logflags = NF_LOG_MASK;
  56
  57         ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
  58         if (ih == NULL) {
  59                 nf_log_buf_add(m, "TRUNCATED");
  60                 return;
  61         }
  62
  63         /* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
  64         nf_log_buf_add(m, "SRC=%pI6 DST=%pI6 ", &ih->saddr, &ih->daddr);
  65
  66         /* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
  67         nf_log_buf_add(m, "LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
  68                ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
  69                (ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20,
  70                ih->hop_limit,
  71                (ntohl(*(__be32 *)ih) & 0x000fffff));
  72
  73         fragment = 0;
  74         ptr = ip6hoff + sizeof(struct ipv6hdr);
  75         currenthdr = ih->nexthdr;
  76         while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
  77                 struct ipv6_opt_hdr _hdr;
  78                 const struct ipv6_opt_hdr *hp;
  79
  80                 hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
  81                 if (hp == NULL) {
  82                         nf_log_buf_add(m, "TRUNCATED");
  83                         return;
  84                 }
  85
  86                 /* Max length: 48 "OPT (...) " */
  87                 if (logflags & XT_LOG_IPOPT)
  88                         nf_log_buf_add(m, "OPT ( ");
  89
  90                 switch (currenthdr) {
  91                 case IPPROTO_FRAGMENT: {
  92                         struct frag_hdr _fhdr;
  93                         const struct frag_hdr *fh;
  94
  95                         nf_log_buf_add(m, "FRAG:");
  96                         fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
  97                                                 &_fhdr);
  98                         if (fh == NULL) {
  99                                 nf_log_buf_add(m, "TRUNCATED ");
 100                                 return;
 101                         }
 102
 103                         /* Max length: 6 "65535 " */
 104                         nf_log_buf_add(m, "%u ", ntohs(fh->frag_off) & 0xFFF8);
 105
 106                         /* Max length: 11 "INCOMPLETE " */
 107                         if (fh->frag_off & htons(0x0001))
 108                                 nf_log_buf_add(m, "INCOMPLETE ");
 109
 110                         nf_log_buf_add(m, "ID:%08x ",
 111                                        ntohl(fh->identification));
 112
 113                         if (ntohs(fh->frag_off) & 0xFFF8)
 114                                 fragment = 1;
 115
 116                         hdrlen = 8;
 117
 118                         break;
 119                 }
 120                 case IPPROTO_DSTOPTS:
 121                 case IPPROTO_ROUTING:
 122                 case IPPROTO_HOPOPTS:
 123                         if (fragment) {
 124                                 if (logflags & XT_LOG_IPOPT)
 125                                         nf_log_buf_add(m, ")");
 126                                 return;
 127                         }
 128                         hdrlen = ipv6_optlen(hp);
 129                         break;
 130                 /* Max Length */
 131                 case IPPROTO_AH:
 132                         if (logflags & XT_LOG_IPOPT) {
 133                                 struct ip_auth_hdr _ahdr;
 134                                 const struct ip_auth_hdr *ah;
 135
 136                                 /* Max length: 3 "AH " */
 137                                 nf_log_buf_add(m, "AH ");
 138
 139                                 if (fragment) {
 140                                         nf_log_buf_add(m, ")");
 141                                         return;
 142                                 }
 143
 144                                 ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
 145                                                         &_ahdr);
 146                                 if (ah == NULL) {
 147                                         /*
 148                                          * Max length: 26 "INCOMPLETE [65535
 149                                          *  bytes] )"
 150                                          */
 151                                         nf_log_buf_add(m, "INCOMPLETE [%u bytes] )",
 152                                                        skb->len - ptr);
 153                                         return;
 154                                 }
 155
 156                                 /* Length: 15 "SPI=0xF1234567 */
 157                                 nf_log_buf_add(m, "SPI=0x%x ", ntohl(ah->spi));
 158
 159                         }
 160
 161                         hdrlen = (hp->hdrlen+2)<<2;
 162                         break;
 163                 case IPPROTO_ESP:
 164                         if (logflags & XT_LOG_IPOPT) {
 165                                 struct ip_esp_hdr _esph;
 166                                 const struct ip_esp_hdr *eh;
 167
 168                                 /* Max length: 4 "ESP " */
 169                                 nf_log_buf_add(m, "ESP ");
 170
 171                                 if (fragment) {
 172                                         nf_log_buf_add(m, ")");
 173                                         return;
 174                                 }
 175
 176                                 /*
 177                                  * Max length: 26 "INCOMPLETE [65535 bytes] )"
 178                                  */
 179                                 eh = skb_header_pointer(skb, ptr, sizeof(_esph),
 180                                                         &_esph);
 181                                 if (eh == NULL) {
 182                                         nf_log_buf_add(m, "INCOMPLETE [%u bytes] )",
 183                                                        skb->len - ptr);
 184                                         return;
 185                                 }
 186
 187                                 /* Length: 16 "SPI=0xF1234567 )" */
 188                                 nf_log_buf_add(m, "SPI=0x%x )",
 189                                                ntohl(eh->spi));
 190                         }
 191                         return;
 192                 default:
 193                         /* Max length: 20 "Unknown Ext Hdr 255" */
 194                         nf_log_buf_add(m, "Unknown Ext Hdr %u", currenthdr);
 195                         return;
 196                 }
 197                 if (logflags & XT_LOG_IPOPT)
 198                         nf_log_buf_add(m, ") ");
 199
 200                 currenthdr = hp->nexthdr;
 201                 ptr += hdrlen;
 202         }
 203
 204         switch (currenthdr) {
 205         case IPPROTO_TCP:
 206                 if (nf_log_dump_tcp_header(m, skb, currenthdr, fragment,
 207                                            ptr, logflags))
 208                         return;
 209                 break;
 210         case IPPROTO_UDP:
 211         case IPPROTO_UDPLITE:
 212                 if (nf_log_dump_udp_header(m, skb, currenthdr, fragment, ptr))
 213                         return;
 214                 break;
 215         case IPPROTO_ICMPV6: {
 216                 struct icmp6hdr _icmp6h;
 217                 const struct icmp6hdr *ic;
 218
 219                 /* Max length: 13 "PROTO=ICMPv6 " */
 220                 nf_log_buf_add(m, "PROTO=ICMPv6 ");
 221
 222                 if (fragment)
 223                         break;
 224
 225                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 226                 ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
 227                 if (ic == NULL) {
 228                         nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
 229                                        skb->len - ptr);
 230                         return;
 231                 }
 232
 233                 /* Max length: 18 "TYPE=255 CODE=255 " */
 234                 nf_log_buf_add(m, "TYPE=%u CODE=%u ",
 235                                ic->icmp6_type, ic->icmp6_code);
 236
 237                 switch (ic->icmp6_type) {
 238                 case ICMPV6_ECHO_REQUEST:
 239                 case ICMPV6_ECHO_REPLY:
 240                         /* Max length: 19 "ID=65535 SEQ=65535 " */
 241                         nf_log_buf_add(m, "ID=%u SEQ=%u ",
 242                                 ntohs(ic->icmp6_identifier),
 243                                 ntohs(ic->icmp6_sequence));
 244                         break;
 245                 case ICMPV6_MGM_QUERY:
 246                 case ICMPV6_MGM_REPORT:
 247                 case ICMPV6_MGM_REDUCTION:
 248                         break;
 249
 250                 case ICMPV6_PARAMPROB:
 251                         /* Max length: 17 "POINTER=ffffffff " */
 252                         nf_log_buf_add(m, "POINTER=%08x ",
 253                                        ntohl(ic->icmp6_pointer));
 254                         /* Fall through */
 255                 case ICMPV6_DEST_UNREACH:
 256                 case ICMPV6_PKT_TOOBIG:
 257                 case ICMPV6_TIME_EXCEED:
 258                         /* Max length: 3+maxlen */
 259                         if (recurse) {
 260                                 nf_log_buf_add(m, "[");
 261                                 dump_ipv6_packet(m, info, skb,
 262                                                  ptr + sizeof(_icmp6h), 0);
 263                                 nf_log_buf_add(m, "] ");
 264                         }
 265
 266                         /* Max length: 10 "MTU=65535 " */
 267                         if (ic->icmp6_type == ICMPV6_PKT_TOOBIG) {
 268                                 nf_log_buf_add(m, "MTU=%u ",
 269                                                ntohl(ic->icmp6_mtu));
 270                         }
 271                 }
 272                 break;
 273         }
 274         /* Max length: 10 "PROTO=255 " */
 275         default:
 276                 nf_log_buf_add(m, "PROTO=%u ", currenthdr);
 277         }
 278
 279         /* Max length: 15 "UID=4294967295 " */
 280         if ((logflags & XT_LOG_UID) && recurse)
 281                 nf_log_dump_sk_uid_gid(m, skb->sk);
 282
 283         /* Max length: 16 "MARK=0xFFFFFFFF " */
 284         if (recurse && skb->mark)
 285                 nf_log_buf_add(m, "MARK=0x%x ", skb->mark);
 286 }
 287
 288 static void dump_ipv6_mac_header(struct nf_log_buf *m,
 289                                  const struct nf_loginfo *info,
 290                                  const struct sk_buff *skb)
 291 {
 292         struct net_device *dev = skb->dev;
 293         unsigned int logflags = 0;
 294
 295         if (info->type == NF_LOG_TYPE_LOG)
 296                 logflags = info->u.log.logflags;
 297
 298         if (!(logflags & XT_LOG_MACDECODE))
 299                 goto fallback;
 300
 301         switch (dev->type) {
 302         case ARPHRD_ETHER:
 303                 nf_log_buf_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ",
 304                        eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
 305                        ntohs(eth_hdr(skb)->h_proto));
 306                 return;
 307         default:
 308                 break;
 309         }
 310
 311 fallback:
 312         nf_log_buf_add(m, "MAC=");
 313         if (dev->hard_header_len &&
 314             skb->mac_header != skb->network_header) {
 315                 const unsigned char *p = skb_mac_header(skb);
 316                 unsigned int len = dev->hard_header_len;
 317                 unsigned int i;
 318
 319                 if (dev->type == ARPHRD_SIT) {
 320                         p -= ETH_HLEN;
 321
 322                         if (p < skb->head)
 323                                 p = NULL;
 324                 }
 325
 326                 if (p != NULL) {
 327                         nf_log_buf_add(m, "%02x", *p++);
 328                         for (i = 1; i < len; i++)
 329                                 nf_log_buf_add(m, ":%02x", *p++);
 330                 }
 331                 nf_log_buf_add(m, " ");
 332
 333                 if (dev->type == ARPHRD_SIT) {
 334                         const struct iphdr *iph =
 335                                 (struct iphdr *)skb_mac_header(skb);
 336                         nf_log_buf_add(m, "TUNNEL=%pI4->%pI4 ", &iph->saddr,
 337                                        &iph->daddr);
 338                 }
 339         } else {
 340                 nf_log_buf_add(m, " ");
 341         }
 342 }
 343
 344 static void nf_log_ip6_packet(struct net *net, u_int8_t pf,
 345                               unsigned int hooknum, const struct sk_buff *skb,
 346                               const struct net_device *in,
 347                               const struct net_device *out,
 348                               const struct nf_loginfo *loginfo,
 349                               const char *prefix)
 350 {
 351         struct nf_log_buf *m;
 352
 353         /* FIXME: Disabled from containers until syslog ns is supported */
 354         if (!net_eq(net, &init_net))
 355                 return;
 356
 357         m = nf_log_buf_open();
 358
 359         if (!loginfo)
 360                 loginfo = &default_loginfo;
 361
 362         nf_log_dump_packet_common(m, pf, hooknum, skb, in, out,
 363                                   loginfo, prefix);
 364
 365         if (in != NULL)
 366                 dump_ipv6_mac_header(m, loginfo, skb);
 367
 368         dump_ipv6_packet(m, loginfo, skb, skb_network_offset(skb), 1);
 369
 370         nf_log_buf_close(m);
 371 }
 372
 373 static struct nf_logger nf_ip6_logger __read_mostly = {
 374         .name           = "nf_log_ipv6",
 375         .type           = NF_LOG_TYPE_LOG,
 376         .logfn          = nf_log_ip6_packet,
 377         .me             = THIS_MODULE,
 378 };
 379
 380 static int __net_init nf_log_ipv6_net_init(struct net *net)
 381 {
 382         nf_log_set(net, NFPROTO_IPV6, &nf_ip6_logger);
 383         return 0;
 384 }
 385
 386 static void __net_exit nf_log_ipv6_net_exit(struct net *net)
 387 {
 388         nf_log_unset(net, &nf_ip6_logger);
 389 }
 390
 391 static struct pernet_operations nf_log_ipv6_net_ops = {
 392         .init = nf_log_ipv6_net_init,
 393         .exit = nf_log_ipv6_net_exit,
 394 };
 395
 396 static int __init nf_log_ipv6_init(void)
 397 {
 398         int ret;
 399
 400         ret = register_pernet_subsys(&nf_log_ipv6_net_ops);
 401         if (ret < 0)
 402                 return ret;
 403
 404         ret = nf_log_register(NFPROTO_IPV6, &nf_ip6_logger);
 405         if (ret < 0) {
 406                 pr_err("failed to register logger\n");
 407                 goto err1;
 408         }
 409
 410         return 0;
 411
 412 err1:
 413         unregister_pernet_subsys(&nf_log_ipv6_net_ops);
 414         return ret;
 415 }
 416
 417 static void __exit nf_log_ipv6_exit(void)
 418 {
 419         unregister_pernet_subsys(&nf_log_ipv6_net_ops);
 420         nf_log_unregister(&nf_ip6_logger);
 421 }
 422
 423 module_init(nf_log_ipv6_init);
 424 module_exit(nf_log_ipv6_exit);
 425
 426 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
 427 MODULE_DESCRIPTION("Netfilter IPv6 packet logging");
 428 MODULE_LICENSE("GPL");
 429 MODULE_ALIAS_NF_LOGGER(AF_INET6, 0);