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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   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_ipv6/ip6_tables.h>
  23 #include <linux/netfilter/xt_LOG.h>
  24 #include <net/netfilter/nf_log.h>
  25
  26 static struct nf_loginfo default_loginfo = {
  27         .type   = NF_LOG_TYPE_LOG,
  28         .u = {
  29                 .log = {
  30                         .level    = 5,
  31                         .logflags = NF_LOG_MASK,
  32                 },
  33         },
  34 };
  35
  36 /* One level of recursion won't kill us */
  37 static void dump_ipv6_packet(struct nf_log_buf *m,
  38                              const struct nf_loginfo *info,
  39                              const struct sk_buff *skb, unsigned int ip6hoff,
  40                              int recurse)
  41 {
  42         u_int8_t currenthdr;
  43         int fragment;
  44         struct ipv6hdr _ip6h;
  45         const struct ipv6hdr *ih;
  46         unsigned int ptr;
  47         unsigned int hdrlen = 0;
  48         unsigned int logflags;
  49
  50         if (info->type == NF_LOG_TYPE_LOG)
  51                 logflags = info->u.log.logflags;
  52         else
  53                 logflags = NF_LOG_MASK;
  54
  55         ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
  56         if (ih == NULL) {
  57                 nf_log_buf_add(m, "TRUNCATED");
  58                 return;
  59         }
  60
  61         /* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
  62         nf_log_buf_add(m, "SRC=%pI6 DST=%pI6 ", &ih->saddr, &ih->daddr);
  63
  64         /* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
  65         nf_log_buf_add(m, "LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
  66                ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
  67                (ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20,
  68                ih->hop_limit,
  69                (ntohl(*(__be32 *)ih) & 0x000fffff));
  70
  71         fragment = 0;
  72         ptr = ip6hoff + sizeof(struct ipv6hdr);
  73         currenthdr = ih->nexthdr;
  74         while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
  75                 struct ipv6_opt_hdr _hdr;
  76                 const struct ipv6_opt_hdr *hp;
  77
  78                 hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
  79                 if (hp == NULL) {
  80                         nf_log_buf_add(m, "TRUNCATED");
  81                         return;
  82                 }
  83
  84                 /* Max length: 48 "OPT (...) " */
  85                 if (logflags & XT_LOG_IPOPT)
  86                         nf_log_buf_add(m, "OPT ( ");
  87
  88                 switch (currenthdr) {
  89                 case IPPROTO_FRAGMENT: {
  90                         struct frag_hdr _fhdr;
  91                         const struct frag_hdr *fh;
  92
  93                         nf_log_buf_add(m, "FRAG:");
  94                         fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
  95                                                 &_fhdr);
  96                         if (fh == NULL) {
  97                                 nf_log_buf_add(m, "TRUNCATED ");
  98                                 return;
  99                         }
 100
 101                         /* Max length: 6 "65535 " */
 102                         nf_log_buf_add(m, "%u ", ntohs(fh->frag_off) & 0xFFF8);
 103
 104                         /* Max length: 11 "INCOMPLETE " */
 105                         if (fh->frag_off & htons(0x0001))
 106                                 nf_log_buf_add(m, "INCOMPLETE ");
 107
 108                         nf_log_buf_add(m, "ID:%08x ",
 109                                        ntohl(fh->identification));
 110
 111                         if (ntohs(fh->frag_off) & 0xFFF8)
 112                                 fragment = 1;
 113
 114                         hdrlen = 8;
 115
 116                         break;
 117                 }
 118                 case IPPROTO_DSTOPTS:
 119                 case IPPROTO_ROUTING:
 120                 case IPPROTO_HOPOPTS:
 121                         if (fragment) {
 122                                 if (logflags & XT_LOG_IPOPT)
 123                                         nf_log_buf_add(m, ")");
 124                                 return;
 125                         }
 126                         hdrlen = ipv6_optlen(hp);
 127                         break;
 128                 /* Max Length */
 129                 case IPPROTO_AH:
 130                         if (logflags & XT_LOG_IPOPT) {
 131                                 struct ip_auth_hdr _ahdr;
 132                                 const struct ip_auth_hdr *ah;
 133
 134                                 /* Max length: 3 "AH " */
 135                                 nf_log_buf_add(m, "AH ");
 136
 137                                 if (fragment) {
 138                                         nf_log_buf_add(m, ")");
 139                                         return;
 140                                 }
 141
 142                                 ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
 143                                                         &_ahdr);
 144                                 if (ah == NULL) {
 145                                         /*
 146                                          * Max length: 26 "INCOMPLETE [65535
 147                                          *  bytes] )"
 148                                          */
 149                                         nf_log_buf_add(m, "INCOMPLETE [%u bytes] )",
 150                                                        skb->len - ptr);
 151                                         return;
 152                                 }
 153
 154                                 /* Length: 15 "SPI=0xF1234567 */
 155                                 nf_log_buf_add(m, "SPI=0x%x ", ntohl(ah->spi));
 156
 157                         }
 158
 159                         hdrlen = (hp->hdrlen+2)<<2;
 160                         break;
 161                 case IPPROTO_ESP:
 162                         if (logflags & XT_LOG_IPOPT) {
 163                                 struct ip_esp_hdr _esph;
 164                                 const struct ip_esp_hdr *eh;
 165
 166                                 /* Max length: 4 "ESP " */
 167                                 nf_log_buf_add(m, "ESP ");
 168
 169                                 if (fragment) {
 170                                         nf_log_buf_add(m, ")");
 171                                         return;
 172                                 }
 173
 174                                 /*
 175                                  * Max length: 26 "INCOMPLETE [65535 bytes] )"
 176                                  */
 177                                 eh = skb_header_pointer(skb, ptr, sizeof(_esph),
 178                                                         &_esph);
 179                                 if (eh == NULL) {
 180                                         nf_log_buf_add(m, "INCOMPLETE [%u bytes] )",
 181                                                        skb->len - ptr);
 182                                         return;
 183                                 }
 184
 185                                 /* Length: 16 "SPI=0xF1234567 )" */
 186                                 nf_log_buf_add(m, "SPI=0x%x )",
 187                                                ntohl(eh->spi));
 188                         }
 189                         return;
 190                 default:
 191                         /* Max length: 20 "Unknown Ext Hdr 255" */
 192                         nf_log_buf_add(m, "Unknown Ext Hdr %u", currenthdr);
 193                         return;
 194                 }
 195                 if (logflags & XT_LOG_IPOPT)
 196                         nf_log_buf_add(m, ") ");
 197
 198                 currenthdr = hp->nexthdr;
 199                 ptr += hdrlen;
 200         }
 201
 202         switch (currenthdr) {
 203         case IPPROTO_TCP:
 204                 if (nf_log_dump_tcp_header(m, skb, currenthdr, fragment,
 205                                            ptr, logflags))
 206                         return;
 207                 break;
 208         case IPPROTO_UDP:
 209         case IPPROTO_UDPLITE:
 210                 if (nf_log_dump_udp_header(m, skb, currenthdr, fragment, ptr))
 211                         return;
 212                 break;
 213         case IPPROTO_ICMPV6: {
 214                 struct icmp6hdr _icmp6h;
 215                 const struct icmp6hdr *ic;
 216
 217                 /* Max length: 13 "PROTO=ICMPv6 " */
 218                 nf_log_buf_add(m, "PROTO=ICMPv6 ");
 219
 220                 if (fragment)
 221                         break;
 222
 223                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 224                 ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
 225                 if (ic == NULL) {
 226                         nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
 227                                        skb->len - ptr);
 228                         return;
 229                 }
 230
 231                 /* Max length: 18 "TYPE=255 CODE=255 " */
 232                 nf_log_buf_add(m, "TYPE=%u CODE=%u ",
 233                                ic->icmp6_type, ic->icmp6_code);
 234
 235                 switch (ic->icmp6_type) {
 236                 case ICMPV6_ECHO_REQUEST:
 237                 case ICMPV6_ECHO_REPLY:
 238                         /* Max length: 19 "ID=65535 SEQ=65535 " */
 239                         nf_log_buf_add(m, "ID=%u SEQ=%u ",
 240                                 ntohs(ic->icmp6_identifier),
 241                                 ntohs(ic->icmp6_sequence));
 242                         break;
 243                 case ICMPV6_MGM_QUERY:
 244                 case ICMPV6_MGM_REPORT:
 245                 case ICMPV6_MGM_REDUCTION:
 246                         break;
 247
 248                 case ICMPV6_PARAMPROB:
 249                         /* Max length: 17 "POINTER=ffffffff " */
 250                         nf_log_buf_add(m, "POINTER=%08x ",
 251                                        ntohl(ic->icmp6_pointer));
 252                         /* Fall through */
 253                 case ICMPV6_DEST_UNREACH:
 254                 case ICMPV6_PKT_TOOBIG:
 255                 case ICMPV6_TIME_EXCEED:
 256                         /* Max length: 3+maxlen */
 257                         if (recurse) {
 258                                 nf_log_buf_add(m, "[");
 259                                 dump_ipv6_packet(m, info, skb,
 260                                                  ptr + sizeof(_icmp6h), 0);
 261                                 nf_log_buf_add(m, "] ");
 262                         }
 263
 264                         /* Max length: 10 "MTU=65535 " */
 265                         if (ic->icmp6_type == ICMPV6_PKT_TOOBIG) {
 266                                 nf_log_buf_add(m, "MTU=%u ",
 267                                                ntohl(ic->icmp6_mtu));
 268                         }
 269                 }
 270                 break;
 271         }
 272         /* Max length: 10 "PROTO=255 " */
 273         default:
 274                 nf_log_buf_add(m, "PROTO=%u ", currenthdr);
 275         }
 276
 277         /* Max length: 15 "UID=4294967295 " */
 278         if ((logflags & XT_LOG_UID) && recurse)
 279                 nf_log_dump_sk_uid_gid(m, skb->sk);
 280
 281         /* Max length: 16 "MARK=0xFFFFFFFF " */
 282         if (recurse && skb->mark)
 283                 nf_log_buf_add(m, "MARK=0x%x ", skb->mark);
 284 }
 285
 286 static void dump_ipv6_mac_header(struct nf_log_buf *m,
 287                                  const struct nf_loginfo *info,
 288                                  const struct sk_buff *skb)
 289 {
 290         struct net_device *dev = skb->dev;
 291         unsigned int logflags = 0;
 292
 293         if (info->type == NF_LOG_TYPE_LOG)
 294                 logflags = info->u.log.logflags;
 295
 296         if (!(logflags & XT_LOG_MACDECODE))
 297                 goto fallback;
 298
 299         switch (dev->type) {
 300         case ARPHRD_ETHER:
 301                 nf_log_buf_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ",
 302                        eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
 303                        ntohs(eth_hdr(skb)->h_proto));
 304                 return;
 305         default:
 306                 break;
 307         }
 308
 309 fallback:
 310         nf_log_buf_add(m, "MAC=");
 311         if (dev->hard_header_len &&
 312             skb->mac_header != skb->network_header) {
 313                 const unsigned char *p = skb_mac_header(skb);
 314                 unsigned int len = dev->hard_header_len;
 315                 unsigned int i;
 316
 317                 if (dev->type == ARPHRD_SIT) {
 318                         p -= ETH_HLEN;
 319
 320                         if (p < skb->head)
 321                                 p = NULL;
 322                 }
 323
 324                 if (p != NULL) {
 325                         nf_log_buf_add(m, "%02x", *p++);
 326                         for (i = 1; i < len; i++)
 327                                 nf_log_buf_add(m, ":%02x", *p++);
 328                 }
 329                 nf_log_buf_add(m, " ");
 330
 331                 if (dev->type == ARPHRD_SIT) {
 332                         const struct iphdr *iph =
 333                                 (struct iphdr *)skb_mac_header(skb);
 334                         nf_log_buf_add(m, "TUNNEL=%pI4->%pI4 ", &iph->saddr,
 335                                        &iph->daddr);
 336                 }
 337         } else {
 338                 nf_log_buf_add(m, " ");
 339         }
 340 }
 341
 342 static void nf_log_ip6_packet(struct net *net, u_int8_t pf,
 343                               unsigned int hooknum, const struct sk_buff *skb,
 344                               const struct net_device *in,
 345                               const struct net_device *out,
 346                               const struct nf_loginfo *loginfo,
 347                               const char *prefix)
 348 {
 349         struct nf_log_buf *m;
 350
 351         /* FIXME: Disabled from containers until syslog ns is supported */
 352         if (!net_eq(net, &init_net))
 353                 return;
 354
 355         m = nf_log_buf_open();
 356
 357         if (!loginfo)
 358                 loginfo = &default_loginfo;
 359
 360         nf_log_dump_packet_common(m, pf, hooknum, skb, in, out,
 361                                   loginfo, prefix);
 362
 363         if (in != NULL)
 364                 dump_ipv6_mac_header(m, loginfo, skb);
 365
 366         dump_ipv6_packet(m, loginfo, skb, skb_network_offset(skb), 1);
 367
 368         nf_log_buf_close(m);
 369 }
 370
 371 static struct nf_logger nf_ip6_logger __read_mostly = {
 372         .name           = "nf_log_ipv6",
 373         .type           = NF_LOG_TYPE_LOG,
 374         .logfn          = nf_log_ip6_packet,
 375         .me             = THIS_MODULE,
 376 };
 377
 378 static int __net_init nf_log_ipv6_net_init(struct net *net)
 379 {
 380         nf_log_set(net, NFPROTO_IPV6, &nf_ip6_logger);
 381         return 0;
 382 }
 383
 384 static void __net_exit nf_log_ipv6_net_exit(struct net *net)
 385 {
 386         nf_log_unset(net, &nf_ip6_logger);
 387 }
 388
 389 static struct pernet_operations nf_log_ipv6_net_ops = {
 390         .init = nf_log_ipv6_net_init,
 391         .exit = nf_log_ipv6_net_exit,
 392 };
 393
 394 static int __init nf_log_ipv6_init(void)
 395 {
 396         int ret;
 397
 398         ret = register_pernet_subsys(&nf_log_ipv6_net_ops);
 399         if (ret < 0)
 400                 return ret;
 401
 402         ret = nf_log_register(NFPROTO_IPV6, &nf_ip6_logger);
 403         if (ret < 0) {
 404                 pr_err("failed to register logger\n");
 405                 goto err1;
 406         }
 407
 408         return 0;
 409
 410 err1:
 411         unregister_pernet_subsys(&nf_log_ipv6_net_ops);
 412         return ret;
 413 }
 414
 415 static void __exit nf_log_ipv6_exit(void)
 416 {
 417         unregister_pernet_subsys(&nf_log_ipv6_net_ops);
 418         nf_log_unregister(&nf_ip6_logger);
 419 }
 420
 421 module_init(nf_log_ipv6_init);
 422 module_exit(nf_log_ipv6_exit);
 423
 424 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
 425 MODULE_DESCRIPTION("Netfilter IPv6 packet logging");
 426 MODULE_LICENSE("GPL");
 427 MODULE_ALIAS_NF_LOGGER(AF_INET6, 0);