net/netfilter/nf_log_syslog.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* (C) 1999-2001 Paul `Rusty' Russell
   3  * (C) 2002-2004 Netfilter Core Team <[email protected]>
   4  */
   5
   6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   7
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/if_arp.h>
  13 #include <linux/ip.h>
  14 #include <net/ipv6.h>
  15 #include <net/icmp.h>
  16 #include <net/udp.h>
  17 #include <net/tcp.h>
  18 #include <net/route.h>
  19
  20 #include <linux/netfilter.h>
  21 #include <linux/netfilter_bridge.h>
  22 #include <linux/netfilter_ipv6.h>
  23 #include <linux/netfilter/xt_LOG.h>
  24 #include <net/netfilter/nf_log.h>
  25
  26 static const struct nf_loginfo default_loginfo = {
  27         .type   = NF_LOG_TYPE_LOG,
  28         .u = {
  29                 .log = {
  30                         .level    = LOGLEVEL_NOTICE,
  31                         .logflags = NF_LOG_DEFAULT_MASK,
  32                 },
  33         },
  34 };
  35
  36 struct arppayload {
  37         unsigned char mac_src[ETH_ALEN];
  38         unsigned char ip_src[4];
  39         unsigned char mac_dst[ETH_ALEN];
  40         unsigned char ip_dst[4];
  41 };
  42
  43 /* Guard against containers flooding syslog. */
  44 static bool nf_log_allowed(const struct net *net)
  45 {
  46         return net_eq(net, &init_net) || sysctl_nf_log_all_netns;
  47 }
  48
  49 static void nf_log_dump_vlan(struct nf_log_buf *m, const struct sk_buff *skb)
  50 {
  51         u16 vid;
  52
  53         if (!skb_vlan_tag_present(skb))
  54                 return;
  55
  56         vid = skb_vlan_tag_get(skb);
  57         nf_log_buf_add(m, "VPROTO=%04x VID=%u ", ntohs(skb->vlan_proto), vid);
  58 }
  59 static void noinline_for_stack
  60 dump_arp_packet(struct nf_log_buf *m,
  61                 const struct nf_loginfo *info,
  62                 const struct sk_buff *skb, unsigned int nhoff)
  63 {
  64         const struct arppayload *ap;
  65         struct arppayload _arpp;
  66         const struct arphdr *ah;
  67         unsigned int logflags;
  68         struct arphdr _arph;
  69
  70         ah = skb_header_pointer(skb, nhoff, sizeof(_arph), &_arph);
  71         if (!ah) {
  72                 nf_log_buf_add(m, "TRUNCATED");
  73                 return;
  74         }
  75
  76         if (info->type == NF_LOG_TYPE_LOG)
  77                 logflags = info->u.log.logflags;
  78         else
  79                 logflags = NF_LOG_DEFAULT_MASK;
  80
  81         if (logflags & NF_LOG_MACDECODE) {
  82                 nf_log_buf_add(m, "MACSRC=%pM MACDST=%pM ",
  83                                eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest);
  84                 nf_log_dump_vlan(m, skb);
  85                 nf_log_buf_add(m, "MACPROTO=%04x ",
  86                                ntohs(eth_hdr(skb)->h_proto));
  87         }
  88
  89         nf_log_buf_add(m, "ARP HTYPE=%d PTYPE=0x%04x OPCODE=%d",
  90                        ntohs(ah->ar_hrd), ntohs(ah->ar_pro), ntohs(ah->ar_op));
  91         /* If it's for Ethernet and the lengths are OK, then log the ARP
  92          * payload.
  93          */
  94         if (ah->ar_hrd != htons(ARPHRD_ETHER) ||
  95             ah->ar_hln != ETH_ALEN ||
  96             ah->ar_pln != sizeof(__be32))
  97                 return;
  98
  99         ap = skb_header_pointer(skb, nhoff + sizeof(_arph), sizeof(_arpp), &_arpp);
 100         if (!ap) {
 101                 nf_log_buf_add(m, " INCOMPLETE [%zu bytes]",
 102                                skb->len - sizeof(_arph));
 103                 return;
 104         }
 105         nf_log_buf_add(m, " MACSRC=%pM IPSRC=%pI4 MACDST=%pM IPDST=%pI4",
 106                        ap->mac_src, ap->ip_src, ap->mac_dst, ap->ip_dst);
 107 }
 108
 109 static void
 110 nf_log_dump_packet_common(struct nf_log_buf *m, u8 pf,
 111                           unsigned int hooknum, const struct sk_buff *skb,
 112                           const struct net_device *in,
 113                           const struct net_device *out,
 114                           const struct nf_loginfo *loginfo, const char *prefix)
 115 {
 116         const struct net_device *physoutdev __maybe_unused;
 117         const struct net_device *physindev __maybe_unused;
 118
 119         nf_log_buf_add(m, KERN_SOH "%c%sIN=%s OUT=%s ",
 120                        '0' + loginfo->u.log.level, prefix,
 121                         in ? in->name : "",
 122                         out ? out->name : "");
 123 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 124         physindev = nf_bridge_get_physindev(skb);
 125         if (physindev && in != physindev)
 126                 nf_log_buf_add(m, "PHYSIN=%s ", physindev->name);
 127         physoutdev = nf_bridge_get_physoutdev(skb);
 128         if (physoutdev && out != physoutdev)
 129                 nf_log_buf_add(m, "PHYSOUT=%s ", physoutdev->name);
 130 #endif
 131 }
 132
 133 static void nf_log_arp_packet(struct net *net, u_int8_t pf,
 134                               unsigned int hooknum, const struct sk_buff *skb,
 135                               const struct net_device *in,
 136                               const struct net_device *out,
 137                               const struct nf_loginfo *loginfo,
 138                               const char *prefix)
 139 {
 140         struct nf_log_buf *m;
 141
 142         if (!nf_log_allowed(net))
 143                 return;
 144
 145         m = nf_log_buf_open();
 146
 147         if (!loginfo)
 148                 loginfo = &default_loginfo;
 149
 150         nf_log_dump_packet_common(m, pf, hooknum, skb, in, out, loginfo,
 151                                   prefix);
 152         dump_arp_packet(m, loginfo, skb, skb_network_offset(skb));
 153
 154         nf_log_buf_close(m);
 155 }
 156
 157 static struct nf_logger nf_arp_logger __read_mostly = {
 158         .name           = "nf_log_arp",
 159         .type           = NF_LOG_TYPE_LOG,
 160         .logfn          = nf_log_arp_packet,
 161         .me             = THIS_MODULE,
 162 };
 163
 164 static void nf_log_dump_sk_uid_gid(struct net *net, struct nf_log_buf *m,
 165                                    struct sock *sk)
 166 {
 167         if (!sk || !sk_fullsock(sk) || !net_eq(net, sock_net(sk)))
 168                 return;
 169
 170         read_lock_bh(&sk->sk_callback_lock);
 171         if (sk->sk_socket && sk->sk_socket->file) {
 172                 const struct cred *cred = sk->sk_socket->file->f_cred;
 173
 174                 nf_log_buf_add(m, "UID=%u GID=%u ",
 175                                from_kuid_munged(&init_user_ns, cred->fsuid),
 176                                from_kgid_munged(&init_user_ns, cred->fsgid));
 177         }
 178         read_unlock_bh(&sk->sk_callback_lock);
 179 }
 180
 181 static noinline_for_stack int
 182 nf_log_dump_tcp_header(struct nf_log_buf *m,
 183                        const struct sk_buff *skb,
 184                        u8 proto, int fragment,
 185                        unsigned int offset,
 186                        unsigned int logflags)
 187 {
 188         struct tcphdr _tcph;
 189         const struct tcphdr *th;
 190
 191         /* Max length: 10 "PROTO=TCP " */
 192         nf_log_buf_add(m, "PROTO=TCP ");
 193
 194         if (fragment)
 195                 return 0;
 196
 197         /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 198         th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
 199         if (!th) {
 200                 nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", skb->len - offset);
 201                 return 1;
 202         }
 203
 204         /* Max length: 20 "SPT=65535 DPT=65535 " */
 205         nf_log_buf_add(m, "SPT=%u DPT=%u ",
 206                        ntohs(th->source), ntohs(th->dest));
 207         /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
 208         if (logflags & NF_LOG_TCPSEQ) {
 209                 nf_log_buf_add(m, "SEQ=%u ACK=%u ",
 210                                ntohl(th->seq), ntohl(th->ack_seq));
 211         }
 212
 213         /* Max length: 13 "WINDOW=65535 " */
 214         nf_log_buf_add(m, "WINDOW=%u ", ntohs(th->window));
 215         /* Max length: 9 "RES=0x3C " */
 216         nf_log_buf_add(m, "RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(th) &
 217                                             TCP_RESERVED_BITS) >> 22));
 218         /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
 219         if (th->cwr)
 220                 nf_log_buf_add(m, "CWR ");
 221         if (th->ece)
 222                 nf_log_buf_add(m, "ECE ");
 223         if (th->urg)
 224                 nf_log_buf_add(m, "URG ");
 225         if (th->ack)
 226                 nf_log_buf_add(m, "ACK ");
 227         if (th->psh)
 228                 nf_log_buf_add(m, "PSH ");
 229         if (th->rst)
 230                 nf_log_buf_add(m, "RST ");
 231         if (th->syn)
 232                 nf_log_buf_add(m, "SYN ");
 233         if (th->fin)
 234                 nf_log_buf_add(m, "FIN ");
 235         /* Max length: 11 "URGP=65535 " */
 236         nf_log_buf_add(m, "URGP=%u ", ntohs(th->urg_ptr));
 237
 238         if ((logflags & NF_LOG_TCPOPT) && th->doff * 4 > sizeof(struct tcphdr)) {
 239                 unsigned int optsize = th->doff * 4 - sizeof(struct tcphdr);
 240                 u8 _opt[60 - sizeof(struct tcphdr)];
 241                 unsigned int i;
 242                 const u8 *op;
 243
 244                 op = skb_header_pointer(skb, offset + sizeof(struct tcphdr),
 245                                         optsize, _opt);
 246                 if (!op) {
 247                         nf_log_buf_add(m, "OPT (TRUNCATED)");
 248                         return 1;
 249                 }
 250
 251                 /* Max length: 127 "OPT (" 15*4*2chars ") " */
 252                 nf_log_buf_add(m, "OPT (");
 253                 for (i = 0; i < optsize; i++)
 254                         nf_log_buf_add(m, "%02X", op[i]);
 255
 256                 nf_log_buf_add(m, ") ");
 257         }
 258
 259         return 0;
 260 }
 261
 262 static noinline_for_stack int
 263 nf_log_dump_udp_header(struct nf_log_buf *m,
 264                        const struct sk_buff *skb,
 265                        u8 proto, int fragment,
 266                        unsigned int offset)
 267 {
 268         struct udphdr _udph;
 269         const struct udphdr *uh;
 270
 271         if (proto == IPPROTO_UDP)
 272                 /* Max length: 10 "PROTO=UDP "     */
 273                 nf_log_buf_add(m, "PROTO=UDP ");
 274         else    /* Max length: 14 "PROTO=UDPLITE " */
 275                 nf_log_buf_add(m, "PROTO=UDPLITE ");
 276
 277         if (fragment)
 278                 goto out;
 279
 280         /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 281         uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
 282         if (!uh) {
 283                 nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", skb->len - offset);
 284
 285                 return 1;
 286         }
 287
 288         /* Max length: 20 "SPT=65535 DPT=65535 " */
 289         nf_log_buf_add(m, "SPT=%u DPT=%u LEN=%u ",
 290                        ntohs(uh->source), ntohs(uh->dest), ntohs(uh->len));
 291
 292 out:
 293         return 0;
 294 }
 295
 296 /* One level of recursion won't kill us */
 297 static noinline_for_stack void
 298 dump_ipv4_packet(struct net *net, struct nf_log_buf *m,
 299                  const struct nf_loginfo *info,
 300                  const struct sk_buff *skb, unsigned int iphoff)
 301 {
 302         const struct iphdr *ih;
 303         unsigned int logflags;
 304         struct iphdr _iph;
 305
 306         if (info->type == NF_LOG_TYPE_LOG)
 307                 logflags = info->u.log.logflags;
 308         else
 309                 logflags = NF_LOG_DEFAULT_MASK;
 310
 311         ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph);
 312         if (!ih) {
 313                 nf_log_buf_add(m, "TRUNCATED");
 314                 return;
 315         }
 316
 317         /* Important fields:
 318          * TOS, len, DF/MF, fragment offset, TTL, src, dst, options.
 319          * Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 "
 320          */
 321         nf_log_buf_add(m, "SRC=%pI4 DST=%pI4 ", &ih->saddr, &ih->daddr);
 322
 323         /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
 324         nf_log_buf_add(m, "LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ",
 325                        ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK,
 326                        ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id));
 327
 328         /* Max length: 6 "CE DF MF " */
 329         if (ntohs(ih->frag_off) & IP_CE)
 330                 nf_log_buf_add(m, "CE ");
 331         if (ntohs(ih->frag_off) & IP_DF)
 332                 nf_log_buf_add(m, "DF ");
 333         if (ntohs(ih->frag_off) & IP_MF)
 334                 nf_log_buf_add(m, "MF ");
 335
 336         /* Max length: 11 "FRAG:65535 " */
 337         if (ntohs(ih->frag_off) & IP_OFFSET)
 338                 nf_log_buf_add(m, "FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);
 339
 340         if ((logflags & NF_LOG_IPOPT) &&
 341             ih->ihl * 4 > sizeof(struct iphdr)) {
 342                 unsigned char _opt[4 * 15 - sizeof(struct iphdr)];
 343                 const unsigned char *op;
 344                 unsigned int i, optsize;
 345
 346                 optsize = ih->ihl * 4 - sizeof(struct iphdr);
 347                 op = skb_header_pointer(skb, iphoff + sizeof(_iph),
 348                                         optsize, _opt);
 349                 if (!op) {
 350                         nf_log_buf_add(m, "TRUNCATED");
 351                         return;
 352                 }
 353
 354                 /* Max length: 127 "OPT (" 15*4*2chars ") " */
 355                 nf_log_buf_add(m, "OPT (");
 356                 for (i = 0; i < optsize; i++)
 357                         nf_log_buf_add(m, "%02X", op[i]);
 358                 nf_log_buf_add(m, ") ");
 359         }
 360
 361         switch (ih->protocol) {
 362         case IPPROTO_TCP:
 363                 if (nf_log_dump_tcp_header(m, skb, ih->protocol,
 364                                            ntohs(ih->frag_off) & IP_OFFSET,
 365                                            iphoff + ih->ihl * 4, logflags))
 366                         return;
 367                 break;
 368         case IPPROTO_UDP:
 369         case IPPROTO_UDPLITE:
 370                 if (nf_log_dump_udp_header(m, skb, ih->protocol,
 371                                            ntohs(ih->frag_off) & IP_OFFSET,
 372                                            iphoff + ih->ihl * 4))
 373                         return;
 374                 break;
 375         case IPPROTO_ICMP: {
 376                 static const size_t required_len[NR_ICMP_TYPES + 1] = {
 377                         [ICMP_ECHOREPLY] = 4,
 378                         [ICMP_DEST_UNREACH] = 8 + sizeof(struct iphdr),
 379                         [ICMP_SOURCE_QUENCH] = 8 + sizeof(struct iphdr),
 380                         [ICMP_REDIRECT] = 8 + sizeof(struct iphdr),
 381                         [ICMP_ECHO] = 4,
 382                         [ICMP_TIME_EXCEEDED] = 8 + sizeof(struct iphdr),
 383                         [ICMP_PARAMETERPROB] = 8 + sizeof(struct iphdr),
 384                         [ICMP_TIMESTAMP] = 20,
 385                         [ICMP_TIMESTAMPREPLY] = 20,
 386                         [ICMP_ADDRESS] = 12,
 387                         [ICMP_ADDRESSREPLY] = 12 };
 388                 const struct icmphdr *ich;
 389                 struct icmphdr _icmph;
 390
 391                 /* Max length: 11 "PROTO=ICMP " */
 392                 nf_log_buf_add(m, "PROTO=ICMP ");
 393
 394                 if (ntohs(ih->frag_off) & IP_OFFSET)
 395                         break;
 396
 397                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 398                 ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
 399                                          sizeof(_icmph), &_icmph);
 400                 if (!ich) {
 401                         nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
 402                                        skb->len - iphoff - ih->ihl * 4);
 403                         break;
 404                 }
 405
 406                 /* Max length: 18 "TYPE=255 CODE=255 " */
 407                 nf_log_buf_add(m, "TYPE=%u CODE=%u ", ich->type, ich->code);
 408
 409                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 410                 if (ich->type <= NR_ICMP_TYPES &&
 411                     required_len[ich->type] &&
 412                     skb->len - iphoff - ih->ihl * 4 < required_len[ich->type]) {
 413                         nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
 414                                        skb->len - iphoff - ih->ihl * 4);
 415                         break;
 416                 }
 417
 418                 switch (ich->type) {
 419                 case ICMP_ECHOREPLY:
 420                 case ICMP_ECHO:
 421                         /* Max length: 19 "ID=65535 SEQ=65535 " */
 422                         nf_log_buf_add(m, "ID=%u SEQ=%u ",
 423                                        ntohs(ich->un.echo.id),
 424                                        ntohs(ich->un.echo.sequence));
 425                         break;
 426
 427                 case ICMP_PARAMETERPROB:
 428                         /* Max length: 14 "PARAMETER=255 " */
 429                         nf_log_buf_add(m, "PARAMETER=%u ",
 430                                        ntohl(ich->un.gateway) >> 24);
 431                         break;
 432                 case ICMP_REDIRECT:
 433                         /* Max length: 24 "GATEWAY=255.255.255.255 " */
 434                         nf_log_buf_add(m, "GATEWAY=%pI4 ", &ich->un.gateway);
 435                         fallthrough;
 436                 case ICMP_DEST_UNREACH:
 437                 case ICMP_SOURCE_QUENCH:
 438                 case ICMP_TIME_EXCEEDED:
 439                         /* Max length: 3+maxlen */
 440                         if (!iphoff) { /* Only recurse once. */
 441                                 nf_log_buf_add(m, "[");
 442                                 dump_ipv4_packet(net, m, info, skb,
 443                                                  iphoff + ih->ihl * 4 + sizeof(_icmph));
 444                                 nf_log_buf_add(m, "] ");
 445                         }
 446
 447                         /* Max length: 10 "MTU=65535 " */
 448                         if (ich->type == ICMP_DEST_UNREACH &&
 449                             ich->code == ICMP_FRAG_NEEDED) {
 450                                 nf_log_buf_add(m, "MTU=%u ",
 451                                                ntohs(ich->un.frag.mtu));
 452                         }
 453                 }
 454                 break;
 455         }
 456         /* Max Length */
 457         case IPPROTO_AH: {
 458                 const struct ip_auth_hdr *ah;
 459                 struct ip_auth_hdr _ahdr;
 460
 461                 if (ntohs(ih->frag_off) & IP_OFFSET)
 462                         break;
 463
 464                 /* Max length: 9 "PROTO=AH " */
 465                 nf_log_buf_add(m, "PROTO=AH ");
 466
 467                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 468                 ah = skb_header_pointer(skb, iphoff + ih->ihl * 4,
 469                                         sizeof(_ahdr), &_ahdr);
 470                 if (!ah) {
 471                         nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
 472                                        skb->len - iphoff - ih->ihl * 4);
 473                         break;
 474                 }
 475
 476                 /* Length: 15 "SPI=0xF1234567 " */
 477                 nf_log_buf_add(m, "SPI=0x%x ", ntohl(ah->spi));
 478                 break;
 479         }
 480         case IPPROTO_ESP: {
 481                 const struct ip_esp_hdr *eh;
 482                 struct ip_esp_hdr _esph;
 483
 484                 /* Max length: 10 "PROTO=ESP " */
 485                 nf_log_buf_add(m, "PROTO=ESP ");
 486
 487                 if (ntohs(ih->frag_off) & IP_OFFSET)
 488                         break;
 489
 490                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 491                 eh = skb_header_pointer(skb, iphoff + ih->ihl * 4,
 492                                         sizeof(_esph), &_esph);
 493                 if (!eh) {
 494                         nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
 495                                        skb->len - iphoff - ih->ihl * 4);
 496                         break;
 497                 }
 498
 499                 /* Length: 15 "SPI=0xF1234567 " */
 500                 nf_log_buf_add(m, "SPI=0x%x ", ntohl(eh->spi));
 501                 break;
 502         }
 503         /* Max length: 10 "PROTO 255 " */
 504         default:
 505                 nf_log_buf_add(m, "PROTO=%u ", ih->protocol);
 506         }
 507
 508         /* Max length: 15 "UID=4294967295 " */
 509         if ((logflags & NF_LOG_UID) && !iphoff)
 510                 nf_log_dump_sk_uid_gid(net, m, skb->sk);
 511
 512         /* Max length: 16 "MARK=0xFFFFFFFF " */
 513         if (!iphoff && skb->mark)
 514                 nf_log_buf_add(m, "MARK=0x%x ", skb->mark);
 515
 516         /* Proto    Max log string length */
 517         /* IP:      40+46+6+11+127 = 230 */
 518         /* TCP:     10+max(25,20+30+13+9+32+11+127) = 252 */
 519         /* UDP:     10+max(25,20) = 35 */
 520         /* UDPLITE: 14+max(25,20) = 39 */
 521         /* ICMP:    11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */
 522         /* ESP:     10+max(25)+15 = 50 */
 523         /* AH:      9+max(25)+15 = 49 */
 524         /* unknown: 10 */
 525
 526         /* (ICMP allows recursion one level deep) */
 527         /* maxlen =  IP + ICMP +  IP + max(TCP,UDP,ICMP,unknown) */
 528         /* maxlen = 230+   91  + 230 + 252 = 803 */
 529 }
 530
 531 static noinline_for_stack void
 532 dump_ipv6_packet(struct net *net, struct nf_log_buf *m,
 533                  const struct nf_loginfo *info,
 534                  const struct sk_buff *skb, unsigned int ip6hoff,
 535                  int recurse)
 536 {
 537         const struct ipv6hdr *ih;
 538         unsigned int hdrlen = 0;
 539         unsigned int logflags;
 540         struct ipv6hdr _ip6h;
 541         unsigned int ptr;
 542         u8 currenthdr;
 543         int fragment;
 544
 545         if (info->type == NF_LOG_TYPE_LOG)
 546                 logflags = info->u.log.logflags;
 547         else
 548                 logflags = NF_LOG_DEFAULT_MASK;
 549
 550         ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
 551         if (!ih) {
 552                 nf_log_buf_add(m, "TRUNCATED");
 553                 return;
 554         }
 555
 556         /* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
 557         nf_log_buf_add(m, "SRC=%pI6 DST=%pI6 ", &ih->saddr, &ih->daddr);
 558
 559         /* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
 560         nf_log_buf_add(m, "LEN=%zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
 561                        ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
 562                        (ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20,
 563                        ih->hop_limit,
 564                        (ntohl(*(__be32 *)ih) & 0x000fffff));
 565
 566         fragment = 0;
 567         ptr = ip6hoff + sizeof(struct ipv6hdr);
 568         currenthdr = ih->nexthdr;
 569         while (currenthdr != NEXTHDR_NONE && nf_ip6_ext_hdr(currenthdr)) {
 570                 struct ipv6_opt_hdr _hdr;
 571                 const struct ipv6_opt_hdr *hp;
 572
 573                 hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
 574                 if (!hp) {
 575                         nf_log_buf_add(m, "TRUNCATED");
 576                         return;
 577                 }
 578
 579                 /* Max length: 48 "OPT (...) " */
 580                 if (logflags & NF_LOG_IPOPT)
 581                         nf_log_buf_add(m, "OPT ( ");
 582
 583                 switch (currenthdr) {
 584                 case IPPROTO_FRAGMENT: {
 585                         struct frag_hdr _fhdr;
 586                         const struct frag_hdr *fh;
 587
 588                         nf_log_buf_add(m, "FRAG:");
 589                         fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
 590                                                 &_fhdr);
 591                         if (!fh) {
 592                                 nf_log_buf_add(m, "TRUNCATED ");
 593                                 return;
 594                         }
 595
 596                         /* Max length: 6 "65535 " */
 597                         nf_log_buf_add(m, "%u ", ntohs(fh->frag_off) & 0xFFF8);
 598
 599                         /* Max length: 11 "INCOMPLETE " */
 600                         if (fh->frag_off & htons(0x0001))
 601                                 nf_log_buf_add(m, "INCOMPLETE ");
 602
 603                         nf_log_buf_add(m, "ID:%08x ",
 604                                        ntohl(fh->identification));
 605
 606                         if (ntohs(fh->frag_off) & 0xFFF8)
 607                                 fragment = 1;
 608
 609                         hdrlen = 8;
 610                         break;
 611                 }
 612                 case IPPROTO_DSTOPTS:
 613                 case IPPROTO_ROUTING:
 614                 case IPPROTO_HOPOPTS:
 615                         if (fragment) {
 616                                 if (logflags & NF_LOG_IPOPT)
 617                                         nf_log_buf_add(m, ")");
 618                                 return;
 619                         }
 620                         hdrlen = ipv6_optlen(hp);
 621                         break;
 622                 /* Max Length */
 623                 case IPPROTO_AH:
 624                         if (logflags & NF_LOG_IPOPT) {
 625                                 struct ip_auth_hdr _ahdr;
 626                                 const struct ip_auth_hdr *ah;
 627
 628                                 /* Max length: 3 "AH " */
 629                                 nf_log_buf_add(m, "AH ");
 630
 631                                 if (fragment) {
 632                                         nf_log_buf_add(m, ")");
 633                                         return;
 634                                 }
 635
 636                                 ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
 637                                                         &_ahdr);
 638                                 if (!ah) {
 639                                         /* Max length: 26 "INCOMPLETE [65535 bytes] )" */
 640                                         nf_log_buf_add(m, "INCOMPLETE [%u bytes] )",
 641                                                        skb->len - ptr);
 642                                         return;
 643                                 }
 644
 645                                 /* Length: 15 "SPI=0xF1234567 */
 646                                 nf_log_buf_add(m, "SPI=0x%x ", ntohl(ah->spi));
 647                         }
 648
 649                         hdrlen = ipv6_authlen(hp);
 650                         break;
 651                 case IPPROTO_ESP:
 652                         if (logflags & NF_LOG_IPOPT) {
 653                                 struct ip_esp_hdr _esph;
 654                                 const struct ip_esp_hdr *eh;
 655
 656                                 /* Max length: 4 "ESP " */
 657                                 nf_log_buf_add(m, "ESP ");
 658
 659                                 if (fragment) {
 660                                         nf_log_buf_add(m, ")");
 661                                         return;
 662                                 }
 663
 664                                 /* Max length: 26 "INCOMPLETE [65535 bytes] )" */
 665                                 eh = skb_header_pointer(skb, ptr, sizeof(_esph),
 666                                                         &_esph);
 667                                 if (!eh) {
 668                                         nf_log_buf_add(m, "INCOMPLETE [%u bytes] )",
 669                                                        skb->len - ptr);
 670                                         return;
 671                                 }
 672
 673                                 /* Length: 16 "SPI=0xF1234567 )" */
 674                                 nf_log_buf_add(m, "SPI=0x%x )",
 675                                                ntohl(eh->spi));
 676                         }
 677                         return;
 678                 default:
 679                         /* Max length: 20 "Unknown Ext Hdr 255" */
 680                         nf_log_buf_add(m, "Unknown Ext Hdr %u", currenthdr);
 681                         return;
 682                 }
 683                 if (logflags & NF_LOG_IPOPT)
 684                         nf_log_buf_add(m, ") ");
 685
 686                 currenthdr = hp->nexthdr;
 687                 ptr += hdrlen;
 688         }
 689
 690         switch (currenthdr) {
 691         case IPPROTO_TCP:
 692                 if (nf_log_dump_tcp_header(m, skb, currenthdr, fragment,
 693                                            ptr, logflags))
 694                         return;
 695                 break;
 696         case IPPROTO_UDP:
 697         case IPPROTO_UDPLITE:
 698                 if (nf_log_dump_udp_header(m, skb, currenthdr, fragment, ptr))
 699                         return;
 700                 break;
 701         case IPPROTO_ICMPV6: {
 702                 struct icmp6hdr _icmp6h;
 703                 const struct icmp6hdr *ic;
 704
 705                 /* Max length: 13 "PROTO=ICMPv6 " */
 706                 nf_log_buf_add(m, "PROTO=ICMPv6 ");
 707
 708                 if (fragment)
 709                         break;
 710
 711                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 712                 ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
 713                 if (!ic) {
 714                         nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
 715                                        skb->len - ptr);
 716                         return;
 717                 }
 718
 719                 /* Max length: 18 "TYPE=255 CODE=255 " */
 720                 nf_log_buf_add(m, "TYPE=%u CODE=%u ",
 721                                ic->icmp6_type, ic->icmp6_code);
 722
 723                 switch (ic->icmp6_type) {
 724                 case ICMPV6_ECHO_REQUEST:
 725                 case ICMPV6_ECHO_REPLY:
 726                         /* Max length: 19 "ID=65535 SEQ=65535 " */
 727                         nf_log_buf_add(m, "ID=%u SEQ=%u ",
 728                                        ntohs(ic->icmp6_identifier),
 729                                        ntohs(ic->icmp6_sequence));
 730                         break;
 731                 case ICMPV6_MGM_QUERY:
 732                 case ICMPV6_MGM_REPORT:
 733                 case ICMPV6_MGM_REDUCTION:
 734                         break;
 735
 736                 case ICMPV6_PARAMPROB:
 737                         /* Max length: 17 "POINTER=ffffffff " */
 738                         nf_log_buf_add(m, "POINTER=%08x ",
 739                                        ntohl(ic->icmp6_pointer));
 740                         fallthrough;
 741                 case ICMPV6_DEST_UNREACH:
 742                 case ICMPV6_PKT_TOOBIG:
 743                 case ICMPV6_TIME_EXCEED:
 744                         /* Max length: 3+maxlen */
 745                         if (recurse) {
 746                                 nf_log_buf_add(m, "[");
 747                                 dump_ipv6_packet(net, m, info, skb,
 748                                                  ptr + sizeof(_icmp6h), 0);
 749                                 nf_log_buf_add(m, "] ");
 750                         }
 751
 752                         /* Max length: 10 "MTU=65535 " */
 753                         if (ic->icmp6_type == ICMPV6_PKT_TOOBIG) {
 754                                 nf_log_buf_add(m, "MTU=%u ",
 755                                                ntohl(ic->icmp6_mtu));
 756                         }
 757                 }
 758                 break;
 759         }
 760         /* Max length: 10 "PROTO=255 " */
 761         default:
 762                 nf_log_buf_add(m, "PROTO=%u ", currenthdr);
 763         }
 764
 765         /* Max length: 15 "UID=4294967295 " */
 766         if ((logflags & NF_LOG_UID) && recurse)
 767                 nf_log_dump_sk_uid_gid(net, m, skb->sk);
 768
 769         /* Max length: 16 "MARK=0xFFFFFFFF " */
 770         if (recurse && skb->mark)
 771                 nf_log_buf_add(m, "MARK=0x%x ", skb->mark);
 772 }
 773
 774 static void dump_mac_header(struct nf_log_buf *m,
 775                             const struct nf_loginfo *info,
 776                             const struct sk_buff *skb)
 777 {
 778         struct net_device *dev = skb->dev;
 779         unsigned int logflags = 0;
 780
 781         if (info->type == NF_LOG_TYPE_LOG)
 782                 logflags = info->u.log.logflags;
 783
 784         if (!(logflags & NF_LOG_MACDECODE))
 785                 goto fallback;
 786
 787         switch (dev->type) {
 788         case ARPHRD_ETHER:
 789                 nf_log_buf_add(m, "MACSRC=%pM MACDST=%pM ",
 790                                eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest);
 791                 nf_log_dump_vlan(m, skb);
 792                 nf_log_buf_add(m, "MACPROTO=%04x ",
 793                                ntohs(eth_hdr(skb)->h_proto));
 794                 return;
 795         default:
 796                 break;
 797         }
 798
 799 fallback:
 800         nf_log_buf_add(m, "MAC=");
 801         if (dev->hard_header_len &&
 802             skb->mac_header != skb->network_header) {
 803                 const unsigned char *p = skb_mac_header(skb);
 804                 unsigned int i;
 805
 806                 if (dev->type == ARPHRD_SIT) {
 807                         p -= ETH_HLEN;
 808
 809                         if (p < skb->head)
 810                                 p = NULL;
 811                 }
 812
 813                 if (p) {
 814                         nf_log_buf_add(m, "%02x", *p++);
 815                         for (i = 1; i < dev->hard_header_len; i++)
 816                                 nf_log_buf_add(m, ":%02x", *p++);
 817                 }
 818
 819                 if (dev->type == ARPHRD_SIT) {
 820                         const struct iphdr *iph =
 821                                 (struct iphdr *)skb_mac_header(skb);
 822
 823                         nf_log_buf_add(m, " TUNNEL=%pI4->%pI4", &iph->saddr,
 824                                        &iph->daddr);
 825                 }
 826         }
 827         nf_log_buf_add(m, " ");
 828 }
 829
 830 static void nf_log_ip_packet(struct net *net, u_int8_t pf,
 831                              unsigned int hooknum, const struct sk_buff *skb,
 832                              const struct net_device *in,
 833                              const struct net_device *out,
 834                              const struct nf_loginfo *loginfo,
 835                              const char *prefix)
 836 {
 837         struct nf_log_buf *m;
 838
 839         if (!nf_log_allowed(net))
 840                 return;
 841
 842         m = nf_log_buf_open();
 843
 844         if (!loginfo)
 845                 loginfo = &default_loginfo;
 846
 847         nf_log_dump_packet_common(m, pf, hooknum, skb, in,
 848                                   out, loginfo, prefix);
 849
 850         if (in)
 851                 dump_mac_header(m, loginfo, skb);
 852
 853         dump_ipv4_packet(net, m, loginfo, skb, skb_network_offset(skb));
 854
 855         nf_log_buf_close(m);
 856 }
 857
 858 static struct nf_logger nf_ip_logger __read_mostly = {
 859         .name           = "nf_log_ipv4",
 860         .type           = NF_LOG_TYPE_LOG,
 861         .logfn          = nf_log_ip_packet,
 862         .me             = THIS_MODULE,
 863 };
 864
 865 static void nf_log_ip6_packet(struct net *net, u_int8_t pf,
 866                               unsigned int hooknum, const struct sk_buff *skb,
 867                               const struct net_device *in,
 868                               const struct net_device *out,
 869                               const struct nf_loginfo *loginfo,
 870                               const char *prefix)
 871 {
 872         struct nf_log_buf *m;
 873
 874         if (!nf_log_allowed(net))
 875                 return;
 876
 877         m = nf_log_buf_open();
 878
 879         if (!loginfo)
 880                 loginfo = &default_loginfo;
 881
 882         nf_log_dump_packet_common(m, pf, hooknum, skb, in, out,
 883                                   loginfo, prefix);
 884
 885         if (in)
 886                 dump_mac_header(m, loginfo, skb);
 887
 888         dump_ipv6_packet(net, m, loginfo, skb, skb_network_offset(skb), 1);
 889
 890         nf_log_buf_close(m);
 891 }
 892
 893 static struct nf_logger nf_ip6_logger __read_mostly = {
 894         .name           = "nf_log_ipv6",
 895         .type           = NF_LOG_TYPE_LOG,
 896         .logfn          = nf_log_ip6_packet,
 897         .me             = THIS_MODULE,
 898 };
 899
 900 static void nf_log_unknown_packet(struct net *net, u_int8_t pf,
 901                                   unsigned int hooknum,
 902                                   const struct sk_buff *skb,
 903                                   const struct net_device *in,
 904                                   const struct net_device *out,
 905                                   const struct nf_loginfo *loginfo,
 906                                   const char *prefix)
 907 {
 908         struct nf_log_buf *m;
 909
 910         if (!nf_log_allowed(net))
 911                 return;
 912
 913         m = nf_log_buf_open();
 914
 915         if (!loginfo)
 916                 loginfo = &default_loginfo;
 917
 918         nf_log_dump_packet_common(m, pf, hooknum, skb, in, out, loginfo,
 919                                   prefix);
 920
 921         dump_mac_header(m, loginfo, skb);
 922
 923         nf_log_buf_close(m);
 924 }
 925
 926 static void nf_log_netdev_packet(struct net *net, u_int8_t pf,
 927                                  unsigned int hooknum,
 928                                  const struct sk_buff *skb,
 929                                  const struct net_device *in,
 930                                  const struct net_device *out,
 931                                  const struct nf_loginfo *loginfo,
 932                                  const char *prefix)
 933 {
 934         switch (skb->protocol) {
 935         case htons(ETH_P_IP):
 936                 nf_log_ip_packet(net, pf, hooknum, skb, in, out, loginfo, prefix);
 937                 break;
 938         case htons(ETH_P_IPV6):
 939                 nf_log_ip6_packet(net, pf, hooknum, skb, in, out, loginfo, prefix);
 940                 break;
 941         case htons(ETH_P_ARP):
 942         case htons(ETH_P_RARP):
 943                 nf_log_arp_packet(net, pf, hooknum, skb, in, out, loginfo, prefix);
 944                 break;
 945         default:
 946                 nf_log_unknown_packet(net, pf, hooknum, skb,
 947                                       in, out, loginfo, prefix);
 948                 break;
 949         }
 950 }
 951
 952 static struct nf_logger nf_netdev_logger __read_mostly = {
 953         .name           = "nf_log_netdev",
 954         .type           = NF_LOG_TYPE_LOG,
 955         .logfn          = nf_log_netdev_packet,
 956         .me             = THIS_MODULE,
 957 };
 958
 959 static struct nf_logger nf_bridge_logger __read_mostly = {
 960         .name           = "nf_log_bridge",
 961         .type           = NF_LOG_TYPE_LOG,
 962         .logfn          = nf_log_netdev_packet,
 963         .me             = THIS_MODULE,
 964 };
 965
 966 static int __net_init nf_log_syslog_net_init(struct net *net)
 967 {
 968         int ret = nf_log_set(net, NFPROTO_IPV4, &nf_ip_logger);
 969
 970         if (ret)
 971                 return ret;
 972
 973         ret = nf_log_set(net, NFPROTO_ARP, &nf_arp_logger);
 974         if (ret)
 975                 goto err1;
 976
 977         ret = nf_log_set(net, NFPROTO_IPV6, &nf_ip6_logger);
 978         if (ret)
 979                 goto err2;
 980
 981         ret = nf_log_set(net, NFPROTO_NETDEV, &nf_netdev_logger);
 982         if (ret)
 983                 goto err3;
 984
 985         ret = nf_log_set(net, NFPROTO_BRIDGE, &nf_bridge_logger);
 986         if (ret)
 987                 goto err4;
 988         return 0;
 989 err4:
 990         nf_log_unset(net, &nf_netdev_logger);
 991 err3:
 992         nf_log_unset(net, &nf_ip6_logger);
 993 err2:
 994         nf_log_unset(net, &nf_arp_logger);
 995 err1:
 996         nf_log_unset(net, &nf_ip_logger);
 997         return ret;
 998 }
 999
1000 static void __net_exit nf_log_syslog_net_exit(struct net *net)
1001 {
1002         nf_log_unset(net, &nf_ip_logger);
1003         nf_log_unset(net, &nf_arp_logger);
1004         nf_log_unset(net, &nf_ip6_logger);
1005         nf_log_unset(net, &nf_netdev_logger);
1006         nf_log_unset(net, &nf_bridge_logger);
1007 }
1008
1009 static struct pernet_operations nf_log_syslog_net_ops = {
1010         .init = nf_log_syslog_net_init,
1011         .exit = nf_log_syslog_net_exit,
1012 };
1013
1014 static int __init nf_log_syslog_init(void)
1015 {
1016         int ret;
1017
1018         ret = register_pernet_subsys(&nf_log_syslog_net_ops);
1019         if (ret < 0)
1020                 return ret;
1021
1022         ret = nf_log_register(NFPROTO_IPV4, &nf_ip_logger);
1023         if (ret < 0)
1024                 goto err1;
1025
1026         ret = nf_log_register(NFPROTO_ARP, &nf_arp_logger);
1027         if (ret < 0)
1028                 goto err2;
1029
1030         ret = nf_log_register(NFPROTO_IPV6, &nf_ip6_logger);
1031         if (ret < 0)
1032                 goto err3;
1033
1034         ret = nf_log_register(NFPROTO_NETDEV, &nf_netdev_logger);
1035         if (ret < 0)
1036                 goto err4;
1037
1038         ret = nf_log_register(NFPROTO_BRIDGE, &nf_bridge_logger);
1039         if (ret < 0)
1040                 goto err5;
1041
1042         return 0;
1043 err5:
1044         nf_log_unregister(&nf_netdev_logger);
1045 err4:
1046         nf_log_unregister(&nf_ip6_logger);
1047 err3:
1048         nf_log_unregister(&nf_arp_logger);
1049 err2:
1050         nf_log_unregister(&nf_ip_logger);
1051 err1:
1052         pr_err("failed to register logger\n");
1053         unregister_pernet_subsys(&nf_log_syslog_net_ops);
1054         return ret;
1055 }
1056
1057 static void __exit nf_log_syslog_exit(void)
1058 {
1059         unregister_pernet_subsys(&nf_log_syslog_net_ops);
1060         nf_log_unregister(&nf_ip_logger);
1061         nf_log_unregister(&nf_arp_logger);
1062         nf_log_unregister(&nf_ip6_logger);
1063         nf_log_unregister(&nf_netdev_logger);
1064         nf_log_unregister(&nf_bridge_logger);
1065 }
1066
1067 module_init(nf_log_syslog_init);
1068 module_exit(nf_log_syslog_exit);
1069
1070 MODULE_AUTHOR("Netfilter Core Team <[email protected]>");
1071 MODULE_DESCRIPTION("Netfilter syslog packet logging");
1072 MODULE_LICENSE("GPL");
1073 MODULE_ALIAS("nf_log_arp");
1074 MODULE_ALIAS("nf_log_bridge");
1075 MODULE_ALIAS("nf_log_ipv4");
1076 MODULE_ALIAS("nf_log_ipv6");
1077 MODULE_ALIAS("nf_log_netdev");
1078 MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 0);
1079 MODULE_ALIAS_NF_LOGGER(AF_INET, 0);
1080 MODULE_ALIAS_NF_LOGGER(3, 0);
1081 MODULE_ALIAS_NF_LOGGER(5, 0); /* NFPROTO_NETDEV */
1082 MODULE_ALIAS_NF_LOGGER(AF_INET6, 0);