linux/net/netfilter/xt_LOG.c
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   1/*
   2 * This is a module which is used for logging packets.
   3 */
   4
   5/* (C) 1999-2001 Paul `Rusty' Russell
   6 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License version 2 as
  10 * published by the Free Software Foundation.
  11 */
  12
  13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14#include <linux/module.h>
  15#include <linux/spinlock.h>
  16#include <linux/skbuff.h>
  17#include <linux/if_arp.h>
  18#include <linux/ip.h>
  19#include <net/ipv6.h>
  20#include <net/icmp.h>
  21#include <net/udp.h>
  22#include <net/tcp.h>
  23#include <net/route.h>
  24
  25#include <linux/netfilter.h>
  26#include <linux/netfilter/x_tables.h>
  27#include <linux/netfilter/xt_LOG.h>
  28#include <linux/netfilter_ipv6/ip6_tables.h>
  29#include <net/netfilter/nf_log.h>
  30#include <net/netfilter/xt_log.h>
  31
  32static struct nf_loginfo default_loginfo = {
  33        .type   = NF_LOG_TYPE_LOG,
  34        .u = {
  35                .log = {
  36                        .level    = 5,
  37                        .logflags = NF_LOG_MASK,
  38                },
  39        },
  40};
  41
  42static int dump_udp_header(struct sbuff *m, const struct sk_buff *skb,
  43                           u8 proto, int fragment, unsigned int offset)
  44{
  45        struct udphdr _udph;
  46        const struct udphdr *uh;
  47
  48        if (proto == IPPROTO_UDP)
  49                /* Max length: 10 "PROTO=UDP "     */
  50                sb_add(m, "PROTO=UDP ");
  51        else    /* Max length: 14 "PROTO=UDPLITE " */
  52                sb_add(m, "PROTO=UDPLITE ");
  53
  54        if (fragment)
  55                goto out;
  56
  57        /* Max length: 25 "INCOMPLETE [65535 bytes] " */
  58        uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
  59        if (uh == NULL) {
  60                sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - offset);
  61
  62                return 1;
  63        }
  64
  65        /* Max length: 20 "SPT=65535 DPT=65535 " */
  66        sb_add(m, "SPT=%u DPT=%u LEN=%u ", ntohs(uh->source), ntohs(uh->dest),
  67                ntohs(uh->len));
  68
  69out:
  70        return 0;
  71}
  72
  73static int dump_tcp_header(struct sbuff *m, const struct sk_buff *skb,
  74                           u8 proto, int fragment, unsigned int offset,
  75                           unsigned int logflags)
  76{
  77        struct tcphdr _tcph;
  78        const struct tcphdr *th;
  79
  80        /* Max length: 10 "PROTO=TCP " */
  81        sb_add(m, "PROTO=TCP ");
  82
  83        if (fragment)
  84                return 0;
  85
  86        /* Max length: 25 "INCOMPLETE [65535 bytes] " */
  87        th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
  88        if (th == NULL) {
  89                sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - offset);
  90                return 1;
  91        }
  92
  93        /* Max length: 20 "SPT=65535 DPT=65535 " */
  94        sb_add(m, "SPT=%u DPT=%u ", ntohs(th->source), ntohs(th->dest));
  95        /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
  96        if (logflags & XT_LOG_TCPSEQ)
  97                sb_add(m, "SEQ=%u ACK=%u ", ntohl(th->seq), ntohl(th->ack_seq));
  98
  99        /* Max length: 13 "WINDOW=65535 " */
 100        sb_add(m, "WINDOW=%u ", ntohs(th->window));
 101        /* Max length: 9 "RES=0x3C " */
 102        sb_add(m, "RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(th) &
 103                                            TCP_RESERVED_BITS) >> 22));
 104        /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
 105        if (th->cwr)
 106                sb_add(m, "CWR ");
 107        if (th->ece)
 108                sb_add(m, "ECE ");
 109        if (th->urg)
 110                sb_add(m, "URG ");
 111        if (th->ack)
 112                sb_add(m, "ACK ");
 113        if (th->psh)
 114                sb_add(m, "PSH ");
 115        if (th->rst)
 116                sb_add(m, "RST ");
 117        if (th->syn)
 118                sb_add(m, "SYN ");
 119        if (th->fin)
 120                sb_add(m, "FIN ");
 121        /* Max length: 11 "URGP=65535 " */
 122        sb_add(m, "URGP=%u ", ntohs(th->urg_ptr));
 123
 124        if ((logflags & XT_LOG_TCPOPT) && th->doff*4 > sizeof(struct tcphdr)) {
 125                u_int8_t _opt[60 - sizeof(struct tcphdr)];
 126                const u_int8_t *op;
 127                unsigned int i;
 128                unsigned int optsize = th->doff*4 - sizeof(struct tcphdr);
 129
 130                op = skb_header_pointer(skb, offset + sizeof(struct tcphdr),
 131                                        optsize, _opt);
 132                if (op == NULL) {
 133                        sb_add(m, "OPT (TRUNCATED)");
 134                        return 1;
 135                }
 136
 137                /* Max length: 127 "OPT (" 15*4*2chars ") " */
 138                sb_add(m, "OPT (");
 139                for (i = 0; i < optsize; i++)
 140                        sb_add(m, "%02X", op[i]);
 141
 142                sb_add(m, ") ");
 143        }
 144
 145        return 0;
 146}
 147
 148static void dump_sk_uid_gid(struct sbuff *m, struct sock *sk)
 149{
 150        if (!sk || sk->sk_state == TCP_TIME_WAIT)
 151                return;
 152
 153        read_lock_bh(&sk->sk_callback_lock);
 154        if (sk->sk_socket && sk->sk_socket->file) {
 155                const struct cred *cred = sk->sk_socket->file->f_cred;
 156                sb_add(m, "UID=%u GID=%u ",
 157                        from_kuid_munged(&init_user_ns, cred->fsuid),
 158                        from_kgid_munged(&init_user_ns, cred->fsgid));
 159        }
 160        read_unlock_bh(&sk->sk_callback_lock);
 161}
 162
 163/* One level of recursion won't kill us */
 164static void dump_ipv4_packet(struct sbuff *m,
 165                        const struct nf_loginfo *info,
 166                        const struct sk_buff *skb,
 167                        unsigned int iphoff)
 168{
 169        struct iphdr _iph;
 170        const struct iphdr *ih;
 171        unsigned int logflags;
 172
 173        if (info->type == NF_LOG_TYPE_LOG)
 174                logflags = info->u.log.logflags;
 175        else
 176                logflags = NF_LOG_MASK;
 177
 178        ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph);
 179        if (ih == NULL) {
 180                sb_add(m, "TRUNCATED");
 181                return;
 182        }
 183
 184        /* Important fields:
 185         * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */
 186        /* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */
 187        sb_add(m, "SRC=%pI4 DST=%pI4 ",
 188               &ih->saddr, &ih->daddr);
 189
 190        /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
 191        sb_add(m, "LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ",
 192               ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK,
 193               ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id));
 194
 195        /* Max length: 6 "CE DF MF " */
 196        if (ntohs(ih->frag_off) & IP_CE)
 197                sb_add(m, "CE ");
 198        if (ntohs(ih->frag_off) & IP_DF)
 199                sb_add(m, "DF ");
 200        if (ntohs(ih->frag_off) & IP_MF)
 201                sb_add(m, "MF ");
 202
 203        /* Max length: 11 "FRAG:65535 " */
 204        if (ntohs(ih->frag_off) & IP_OFFSET)
 205                sb_add(m, "FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);
 206
 207        if ((logflags & XT_LOG_IPOPT) &&
 208            ih->ihl * 4 > sizeof(struct iphdr)) {
 209                const unsigned char *op;
 210                unsigned char _opt[4 * 15 - sizeof(struct iphdr)];
 211                unsigned int i, optsize;
 212
 213                optsize = ih->ihl * 4 - sizeof(struct iphdr);
 214                op = skb_header_pointer(skb, iphoff+sizeof(_iph),
 215                                        optsize, _opt);
 216                if (op == NULL) {
 217                        sb_add(m, "TRUNCATED");
 218                        return;
 219                }
 220
 221                /* Max length: 127 "OPT (" 15*4*2chars ") " */
 222                sb_add(m, "OPT (");
 223                for (i = 0; i < optsize; i++)
 224                        sb_add(m, "%02X", op[i]);
 225                sb_add(m, ") ");
 226        }
 227
 228        switch (ih->protocol) {
 229        case IPPROTO_TCP:
 230                if (dump_tcp_header(m, skb, ih->protocol,
 231                                    ntohs(ih->frag_off) & IP_OFFSET,
 232                                    iphoff+ih->ihl*4, logflags))
 233                        return;
 234                break;
 235        case IPPROTO_UDP:
 236        case IPPROTO_UDPLITE:
 237                if (dump_udp_header(m, skb, ih->protocol,
 238                                    ntohs(ih->frag_off) & IP_OFFSET,
 239                                    iphoff+ih->ihl*4))
 240                        return;
 241                break;
 242        case IPPROTO_ICMP: {
 243                struct icmphdr _icmph;
 244                const struct icmphdr *ich;
 245                static const size_t required_len[NR_ICMP_TYPES+1]
 246                        = { [ICMP_ECHOREPLY] = 4,
 247                            [ICMP_DEST_UNREACH]
 248                            = 8 + sizeof(struct iphdr),
 249                            [ICMP_SOURCE_QUENCH]
 250                            = 8 + sizeof(struct iphdr),
 251                            [ICMP_REDIRECT]
 252                            = 8 + sizeof(struct iphdr),
 253                            [ICMP_ECHO] = 4,
 254                            [ICMP_TIME_EXCEEDED]
 255                            = 8 + sizeof(struct iphdr),
 256                            [ICMP_PARAMETERPROB]
 257                            = 8 + sizeof(struct iphdr),
 258                            [ICMP_TIMESTAMP] = 20,
 259                            [ICMP_TIMESTAMPREPLY] = 20,
 260                            [ICMP_ADDRESS] = 12,
 261                            [ICMP_ADDRESSREPLY] = 12 };
 262
 263                /* Max length: 11 "PROTO=ICMP " */
 264                sb_add(m, "PROTO=ICMP ");
 265
 266                if (ntohs(ih->frag_off) & IP_OFFSET)
 267                        break;
 268
 269                /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 270                ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
 271                                         sizeof(_icmph), &_icmph);
 272                if (ich == NULL) {
 273                        sb_add(m, "INCOMPLETE [%u bytes] ",
 274                               skb->len - iphoff - ih->ihl*4);
 275                        break;
 276                }
 277
 278                /* Max length: 18 "TYPE=255 CODE=255 " */
 279                sb_add(m, "TYPE=%u CODE=%u ", ich->type, ich->code);
 280
 281                /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 282                if (ich->type <= NR_ICMP_TYPES &&
 283                    required_len[ich->type] &&
 284                    skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) {
 285                        sb_add(m, "INCOMPLETE [%u bytes] ",
 286                               skb->len - iphoff - ih->ihl*4);
 287                        break;
 288                }
 289
 290                switch (ich->type) {
 291                case ICMP_ECHOREPLY:
 292                case ICMP_ECHO:
 293                        /* Max length: 19 "ID=65535 SEQ=65535 " */
 294                        sb_add(m, "ID=%u SEQ=%u ",
 295                               ntohs(ich->un.echo.id),
 296                               ntohs(ich->un.echo.sequence));
 297                        break;
 298
 299                case ICMP_PARAMETERPROB:
 300                        /* Max length: 14 "PARAMETER=255 " */
 301                        sb_add(m, "PARAMETER=%u ",
 302                               ntohl(ich->un.gateway) >> 24);
 303                        break;
 304                case ICMP_REDIRECT:
 305                        /* Max length: 24 "GATEWAY=255.255.255.255 " */
 306                        sb_add(m, "GATEWAY=%pI4 ", &ich->un.gateway);
 307                        /* Fall through */
 308                case ICMP_DEST_UNREACH:
 309                case ICMP_SOURCE_QUENCH:
 310                case ICMP_TIME_EXCEEDED:
 311                        /* Max length: 3+maxlen */
 312                        if (!iphoff) { /* Only recurse once. */
 313                                sb_add(m, "[");
 314                                dump_ipv4_packet(m, info, skb,
 315                                            iphoff + ih->ihl*4+sizeof(_icmph));
 316                                sb_add(m, "] ");
 317                        }
 318
 319                        /* Max length: 10 "MTU=65535 " */
 320                        if (ich->type == ICMP_DEST_UNREACH &&
 321                            ich->code == ICMP_FRAG_NEEDED)
 322                                sb_add(m, "MTU=%u ", ntohs(ich->un.frag.mtu));
 323                }
 324                break;
 325        }
 326        /* Max Length */
 327        case IPPROTO_AH: {
 328                struct ip_auth_hdr _ahdr;
 329                const struct ip_auth_hdr *ah;
 330
 331                if (ntohs(ih->frag_off) & IP_OFFSET)
 332                        break;
 333
 334                /* Max length: 9 "PROTO=AH " */
 335                sb_add(m, "PROTO=AH ");
 336
 337                /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 338                ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
 339                                        sizeof(_ahdr), &_ahdr);
 340                if (ah == NULL) {
 341                        sb_add(m, "INCOMPLETE [%u bytes] ",
 342                               skb->len - iphoff - ih->ihl*4);
 343                        break;
 344                }
 345
 346                /* Length: 15 "SPI=0xF1234567 " */
 347                sb_add(m, "SPI=0x%x ", ntohl(ah->spi));
 348                break;
 349        }
 350        case IPPROTO_ESP: {
 351                struct ip_esp_hdr _esph;
 352                const struct ip_esp_hdr *eh;
 353
 354                /* Max length: 10 "PROTO=ESP " */
 355                sb_add(m, "PROTO=ESP ");
 356
 357                if (ntohs(ih->frag_off) & IP_OFFSET)
 358                        break;
 359
 360                /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 361                eh = skb_header_pointer(skb, iphoff+ih->ihl*4,
 362                                        sizeof(_esph), &_esph);
 363                if (eh == NULL) {
 364                        sb_add(m, "INCOMPLETE [%u bytes] ",
 365                               skb->len - iphoff - ih->ihl*4);
 366                        break;
 367                }
 368
 369                /* Length: 15 "SPI=0xF1234567 " */
 370                sb_add(m, "SPI=0x%x ", ntohl(eh->spi));
 371                break;
 372        }
 373        /* Max length: 10 "PROTO 255 " */
 374        default:
 375                sb_add(m, "PROTO=%u ", ih->protocol);
 376        }
 377
 378        /* Max length: 15 "UID=4294967295 " */
 379        if ((logflags & XT_LOG_UID) && !iphoff)
 380                dump_sk_uid_gid(m, skb->sk);
 381
 382        /* Max length: 16 "MARK=0xFFFFFFFF " */
 383        if (!iphoff && skb->mark)
 384                sb_add(m, "MARK=0x%x ", skb->mark);
 385
 386        /* Proto    Max log string length */
 387        /* IP:      40+46+6+11+127 = 230 */
 388        /* TCP:     10+max(25,20+30+13+9+32+11+127) = 252 */
 389        /* UDP:     10+max(25,20) = 35 */
 390        /* UDPLITE: 14+max(25,20) = 39 */
 391        /* ICMP:    11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */
 392        /* ESP:     10+max(25)+15 = 50 */
 393        /* AH:      9+max(25)+15 = 49 */
 394        /* unknown: 10 */
 395
 396        /* (ICMP allows recursion one level deep) */
 397        /* maxlen =  IP + ICMP +  IP + max(TCP,UDP,ICMP,unknown) */
 398        /* maxlen = 230+   91  + 230 + 252 = 803 */
 399}
 400
 401static void dump_ipv4_mac_header(struct sbuff *m,
 402                            const struct nf_loginfo *info,
 403                            const struct sk_buff *skb)
 404{
 405        struct net_device *dev = skb->dev;
 406        unsigned int logflags = 0;
 407
 408        if (info->type == NF_LOG_TYPE_LOG)
 409                logflags = info->u.log.logflags;
 410
 411        if (!(logflags & XT_LOG_MACDECODE))
 412                goto fallback;
 413
 414        switch (dev->type) {
 415        case ARPHRD_ETHER:
 416                sb_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ",
 417                       eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
 418                       ntohs(eth_hdr(skb)->h_proto));
 419                return;
 420        default:
 421                break;
 422        }
 423
 424fallback:
 425        sb_add(m, "MAC=");
 426        if (dev->hard_header_len &&
 427            skb->mac_header != skb->network_header) {
 428                const unsigned char *p = skb_mac_header(skb);
 429                unsigned int i;
 430
 431                sb_add(m, "%02x", *p++);
 432                for (i = 1; i < dev->hard_header_len; i++, p++)
 433                        sb_add(m, ":%02x", *p);
 434        }
 435        sb_add(m, " ");
 436}
 437
 438static void
 439log_packet_common(struct sbuff *m,
 440                  u_int8_t pf,
 441                  unsigned int hooknum,
 442                  const struct sk_buff *skb,
 443                  const struct net_device *in,
 444                  const struct net_device *out,
 445                  const struct nf_loginfo *loginfo,
 446                  const char *prefix)
 447{
 448        sb_add(m, KERN_SOH "%c%sIN=%s OUT=%s ",
 449               '0' + loginfo->u.log.level, prefix,
 450               in ? in->name : "",
 451               out ? out->name : "");
 452#ifdef CONFIG_BRIDGE_NETFILTER
 453        if (skb->nf_bridge) {
 454                const struct net_device *physindev;
 455                const struct net_device *physoutdev;
 456
 457                physindev = skb->nf_bridge->physindev;
 458                if (physindev && in != physindev)
 459                        sb_add(m, "PHYSIN=%s ", physindev->name);
 460                physoutdev = skb->nf_bridge->physoutdev;
 461                if (physoutdev && out != physoutdev)
 462                        sb_add(m, "PHYSOUT=%s ", physoutdev->name);
 463        }
 464#endif
 465}
 466
 467
 468static void
 469ipt_log_packet(struct net *net,
 470               u_int8_t pf,
 471               unsigned int hooknum,
 472               const struct sk_buff *skb,
 473               const struct net_device *in,
 474               const struct net_device *out,
 475               const struct nf_loginfo *loginfo,
 476               const char *prefix)
 477{
 478        struct sbuff *m;
 479
 480        /* FIXME: Disabled from containers until syslog ns is supported */
 481        if (!net_eq(net, &init_net))
 482                return;
 483
 484        m = sb_open();
 485
 486        if (!loginfo)
 487                loginfo = &default_loginfo;
 488
 489        log_packet_common(m, pf, hooknum, skb, in, out, loginfo, prefix);
 490
 491        if (in != NULL)
 492                dump_ipv4_mac_header(m, loginfo, skb);
 493
 494        dump_ipv4_packet(m, loginfo, skb, 0);
 495
 496        sb_close(m);
 497}
 498
 499#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 500/* One level of recursion won't kill us */
 501static void dump_ipv6_packet(struct sbuff *m,
 502                        const struct nf_loginfo *info,
 503                        const struct sk_buff *skb, unsigned int ip6hoff,
 504                        int recurse)
 505{
 506        u_int8_t currenthdr;
 507        int fragment;
 508        struct ipv6hdr _ip6h;
 509        const struct ipv6hdr *ih;
 510        unsigned int ptr;
 511        unsigned int hdrlen = 0;
 512        unsigned int logflags;
 513
 514        if (info->type == NF_LOG_TYPE_LOG)
 515                logflags = info->u.log.logflags;
 516        else
 517                logflags = NF_LOG_MASK;
 518
 519        ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
 520        if (ih == NULL) {
 521                sb_add(m, "TRUNCATED");
 522                return;
 523        }
 524
 525        /* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
 526        sb_add(m, "SRC=%pI6 DST=%pI6 ", &ih->saddr, &ih->daddr);
 527
 528        /* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
 529        sb_add(m, "LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
 530               ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
 531               (ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20,
 532               ih->hop_limit,
 533               (ntohl(*(__be32 *)ih) & 0x000fffff));
 534
 535        fragment = 0;
 536        ptr = ip6hoff + sizeof(struct ipv6hdr);
 537        currenthdr = ih->nexthdr;
 538        while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
 539                struct ipv6_opt_hdr _hdr;
 540                const struct ipv6_opt_hdr *hp;
 541
 542                hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
 543                if (hp == NULL) {
 544                        sb_add(m, "TRUNCATED");
 545                        return;
 546                }
 547
 548                /* Max length: 48 "OPT (...) " */
 549                if (logflags & XT_LOG_IPOPT)
 550                        sb_add(m, "OPT ( ");
 551
 552                switch (currenthdr) {
 553                case IPPROTO_FRAGMENT: {
 554                        struct frag_hdr _fhdr;
 555                        const struct frag_hdr *fh;
 556
 557                        sb_add(m, "FRAG:");
 558                        fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
 559                                                &_fhdr);
 560                        if (fh == NULL) {
 561                                sb_add(m, "TRUNCATED ");
 562                                return;
 563                        }
 564
 565                        /* Max length: 6 "65535 " */
 566                        sb_add(m, "%u ", ntohs(fh->frag_off) & 0xFFF8);
 567
 568                        /* Max length: 11 "INCOMPLETE " */
 569                        if (fh->frag_off & htons(0x0001))
 570                                sb_add(m, "INCOMPLETE ");
 571
 572                        sb_add(m, "ID:%08x ", ntohl(fh->identification));
 573
 574                        if (ntohs(fh->frag_off) & 0xFFF8)
 575                                fragment = 1;
 576
 577                        hdrlen = 8;
 578
 579                        break;
 580                }
 581                case IPPROTO_DSTOPTS:
 582                case IPPROTO_ROUTING:
 583                case IPPROTO_HOPOPTS:
 584                        if (fragment) {
 585                                if (logflags & XT_LOG_IPOPT)
 586                                        sb_add(m, ")");
 587                                return;
 588                        }
 589                        hdrlen = ipv6_optlen(hp);
 590                        break;
 591                /* Max Length */
 592                case IPPROTO_AH:
 593                        if (logflags & XT_LOG_IPOPT) {
 594                                struct ip_auth_hdr _ahdr;
 595                                const struct ip_auth_hdr *ah;
 596
 597                                /* Max length: 3 "AH " */
 598                                sb_add(m, "AH ");
 599
 600                                if (fragment) {
 601                                        sb_add(m, ")");
 602                                        return;
 603                                }
 604
 605                                ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
 606                                                        &_ahdr);
 607                                if (ah == NULL) {
 608                                        /*
 609                                         * Max length: 26 "INCOMPLETE [65535
 610                                         *  bytes] )"
 611                                         */
 612                                        sb_add(m, "INCOMPLETE [%u bytes] )",
 613                                               skb->len - ptr);
 614                                        return;
 615                                }
 616
 617                                /* Length: 15 "SPI=0xF1234567 */
 618                                sb_add(m, "SPI=0x%x ", ntohl(ah->spi));
 619
 620                        }
 621
 622                        hdrlen = (hp->hdrlen+2)<<2;
 623                        break;
 624                case IPPROTO_ESP:
 625                        if (logflags & XT_LOG_IPOPT) {
 626                                struct ip_esp_hdr _esph;
 627                                const struct ip_esp_hdr *eh;
 628
 629                                /* Max length: 4 "ESP " */
 630                                sb_add(m, "ESP ");
 631
 632                                if (fragment) {
 633                                        sb_add(m, ")");
 634                                        return;
 635                                }
 636
 637                                /*
 638                                 * Max length: 26 "INCOMPLETE [65535 bytes] )"
 639                                 */
 640                                eh = skb_header_pointer(skb, ptr, sizeof(_esph),
 641                                                        &_esph);
 642                                if (eh == NULL) {
 643                                        sb_add(m, "INCOMPLETE [%u bytes] )",
 644                                               skb->len - ptr);
 645                                        return;
 646                                }
 647
 648                                /* Length: 16 "SPI=0xF1234567 )" */
 649                                sb_add(m, "SPI=0x%x )", ntohl(eh->spi));
 650
 651                        }
 652                        return;
 653                default:
 654                        /* Max length: 20 "Unknown Ext Hdr 255" */
 655                        sb_add(m, "Unknown Ext Hdr %u", currenthdr);
 656                        return;
 657                }
 658                if (logflags & XT_LOG_IPOPT)
 659                        sb_add(m, ") ");
 660
 661                currenthdr = hp->nexthdr;
 662                ptr += hdrlen;
 663        }
 664
 665        switch (currenthdr) {
 666        case IPPROTO_TCP:
 667                if (dump_tcp_header(m, skb, currenthdr, fragment, ptr,
 668                    logflags))
 669                        return;
 670                break;
 671        case IPPROTO_UDP:
 672        case IPPROTO_UDPLITE:
 673                if (dump_udp_header(m, skb, currenthdr, fragment, ptr))
 674                        return;
 675                break;
 676        case IPPROTO_ICMPV6: {
 677                struct icmp6hdr _icmp6h;
 678                const struct icmp6hdr *ic;
 679
 680                /* Max length: 13 "PROTO=ICMPv6 " */
 681                sb_add(m, "PROTO=ICMPv6 ");
 682
 683                if (fragment)
 684                        break;
 685
 686                /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 687                ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
 688                if (ic == NULL) {
 689                        sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - ptr);
 690                        return;
 691                }
 692
 693                /* Max length: 18 "TYPE=255 CODE=255 " */
 694                sb_add(m, "TYPE=%u CODE=%u ", ic->icmp6_type, ic->icmp6_code);
 695
 696                switch (ic->icmp6_type) {
 697                case ICMPV6_ECHO_REQUEST:
 698                case ICMPV6_ECHO_REPLY:
 699                        /* Max length: 19 "ID=65535 SEQ=65535 " */
 700                        sb_add(m, "ID=%u SEQ=%u ",
 701                                ntohs(ic->icmp6_identifier),
 702                                ntohs(ic->icmp6_sequence));
 703                        break;
 704                case ICMPV6_MGM_QUERY:
 705                case ICMPV6_MGM_REPORT:
 706                case ICMPV6_MGM_REDUCTION:
 707                        break;
 708
 709                case ICMPV6_PARAMPROB:
 710                        /* Max length: 17 "POINTER=ffffffff " */
 711                        sb_add(m, "POINTER=%08x ", ntohl(ic->icmp6_pointer));
 712                        /* Fall through */
 713                case ICMPV6_DEST_UNREACH:
 714                case ICMPV6_PKT_TOOBIG:
 715                case ICMPV6_TIME_EXCEED:
 716                        /* Max length: 3+maxlen */
 717                        if (recurse) {
 718                                sb_add(m, "[");
 719                                dump_ipv6_packet(m, info, skb,
 720                                            ptr + sizeof(_icmp6h), 0);
 721                                sb_add(m, "] ");
 722                        }
 723
 724                        /* Max length: 10 "MTU=65535 " */
 725                        if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
 726                                sb_add(m, "MTU=%u ", ntohl(ic->icmp6_mtu));
 727                }
 728                break;
 729        }
 730        /* Max length: 10 "PROTO=255 " */
 731        default:
 732                sb_add(m, "PROTO=%u ", currenthdr);
 733        }
 734
 735        /* Max length: 15 "UID=4294967295 " */
 736        if ((logflags & XT_LOG_UID) && recurse)
 737                dump_sk_uid_gid(m, skb->sk);
 738
 739        /* Max length: 16 "MARK=0xFFFFFFFF " */
 740        if (recurse && skb->mark)
 741                sb_add(m, "MARK=0x%x ", skb->mark);
 742}
 743
 744static void dump_ipv6_mac_header(struct sbuff *m,
 745                            const struct nf_loginfo *info,
 746                            const struct sk_buff *skb)
 747{
 748        struct net_device *dev = skb->dev;
 749        unsigned int logflags = 0;
 750
 751        if (info->type == NF_LOG_TYPE_LOG)
 752                logflags = info->u.log.logflags;
 753
 754        if (!(logflags & XT_LOG_MACDECODE))
 755                goto fallback;
 756
 757        switch (dev->type) {
 758        case ARPHRD_ETHER:
 759                sb_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ",
 760                       eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
 761                       ntohs(eth_hdr(skb)->h_proto));
 762                return;
 763        default:
 764                break;
 765        }
 766
 767fallback:
 768        sb_add(m, "MAC=");
 769        if (dev->hard_header_len &&
 770            skb->mac_header != skb->network_header) {
 771                const unsigned char *p = skb_mac_header(skb);
 772                unsigned int len = dev->hard_header_len;
 773                unsigned int i;
 774
 775                if (dev->type == ARPHRD_SIT) {
 776                        p -= ETH_HLEN;
 777
 778                        if (p < skb->head)
 779                                p = NULL;
 780                }
 781
 782                if (p != NULL) {
 783                        sb_add(m, "%02x", *p++);
 784                        for (i = 1; i < len; i++)
 785                                sb_add(m, ":%02x", *p++);
 786                }
 787                sb_add(m, " ");
 788
 789                if (dev->type == ARPHRD_SIT) {
 790                        const struct iphdr *iph =
 791                                (struct iphdr *)skb_mac_header(skb);
 792                        sb_add(m, "TUNNEL=%pI4->%pI4 ", &iph->saddr,
 793                               &iph->daddr);
 794                }
 795        } else
 796                sb_add(m, " ");
 797}
 798
 799static void
 800ip6t_log_packet(struct net *net,
 801                u_int8_t pf,
 802                unsigned int hooknum,
 803                const struct sk_buff *skb,
 804                const struct net_device *in,
 805                const struct net_device *out,
 806                const struct nf_loginfo *loginfo,
 807                const char *prefix)
 808{
 809        struct sbuff *m;
 810
 811        /* FIXME: Disabled from containers until syslog ns is supported */
 812        if (!net_eq(net, &init_net))
 813                return;
 814
 815        m = sb_open();
 816
 817        if (!loginfo)
 818                loginfo = &default_loginfo;
 819
 820        log_packet_common(m, pf, hooknum, skb, in, out, loginfo, prefix);
 821
 822        if (in != NULL)
 823                dump_ipv6_mac_header(m, loginfo, skb);
 824
 825        dump_ipv6_packet(m, loginfo, skb, skb_network_offset(skb), 1);
 826
 827        sb_close(m);
 828}
 829#endif
 830
 831static unsigned int
 832log_tg(struct sk_buff *skb, const struct xt_action_param *par)
 833{
 834        const struct xt_log_info *loginfo = par->targinfo;
 835        struct nf_loginfo li;
 836        struct net *net = dev_net(par->in ? par->in : par->out);
 837
 838        li.type = NF_LOG_TYPE_LOG;
 839        li.u.log.level = loginfo->level;
 840        li.u.log.logflags = loginfo->logflags;
 841
 842        if (par->family == NFPROTO_IPV4)
 843                ipt_log_packet(net, NFPROTO_IPV4, par->hooknum, skb, par->in,
 844                               par->out, &li, loginfo->prefix);
 845#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 846        else if (par->family == NFPROTO_IPV6)
 847                ip6t_log_packet(net, NFPROTO_IPV6, par->hooknum, skb, par->in,
 848                                par->out, &li, loginfo->prefix);
 849#endif
 850        else
 851                WARN_ON_ONCE(1);
 852
 853        return XT_CONTINUE;
 854}
 855
 856static int log_tg_check(const struct xt_tgchk_param *par)
 857{
 858        const struct xt_log_info *loginfo = par->targinfo;
 859
 860        if (par->family != NFPROTO_IPV4 && par->family != NFPROTO_IPV6)
 861                return -EINVAL;
 862
 863        if (loginfo->level >= 8) {
 864                pr_debug("level %u >= 8\n", loginfo->level);
 865                return -EINVAL;
 866        }
 867
 868        if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
 869                pr_debug("prefix is not null-terminated\n");
 870                return -EINVAL;
 871        }
 872
 873        return 0;
 874}
 875
 876static struct xt_target log_tg_regs[] __read_mostly = {
 877        {
 878                .name           = "LOG",
 879                .family         = NFPROTO_IPV4,
 880                .target         = log_tg,
 881                .targetsize     = sizeof(struct xt_log_info),
 882                .checkentry     = log_tg_check,
 883                .me             = THIS_MODULE,
 884        },
 885#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 886        {
 887                .name           = "LOG",
 888                .family         = NFPROTO_IPV6,
 889                .target         = log_tg,
 890                .targetsize     = sizeof(struct xt_log_info),
 891                .checkentry     = log_tg_check,
 892                .me             = THIS_MODULE,
 893        },
 894#endif
 895};
 896
 897static struct nf_logger ipt_log_logger __read_mostly = {
 898        .name           = "ipt_LOG",
 899        .logfn          = &ipt_log_packet,
 900        .me             = THIS_MODULE,
 901};
 902
 903#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 904static struct nf_logger ip6t_log_logger __read_mostly = {
 905        .name           = "ip6t_LOG",
 906        .logfn          = &ip6t_log_packet,
 907        .me             = THIS_MODULE,
 908};
 909#endif
 910
 911static int __net_init log_net_init(struct net *net)
 912{
 913        nf_log_set(net, NFPROTO_IPV4, &ipt_log_logger);
 914#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 915        nf_log_set(net, NFPROTO_IPV6, &ip6t_log_logger);
 916#endif
 917        return 0;
 918}
 919
 920static void __net_exit log_net_exit(struct net *net)
 921{
 922        nf_log_unset(net, &ipt_log_logger);
 923#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 924        nf_log_unset(net, &ip6t_log_logger);
 925#endif
 926}
 927
 928static struct pernet_operations log_net_ops = {
 929        .init = log_net_init,
 930        .exit = log_net_exit,
 931};
 932
 933static int __init log_tg_init(void)
 934{
 935        int ret;
 936
 937        ret = register_pernet_subsys(&log_net_ops);
 938        if (ret < 0)
 939                goto err_pernet;
 940
 941        ret = xt_register_targets(log_tg_regs, ARRAY_SIZE(log_tg_regs));
 942        if (ret < 0)
 943                goto err_target;
 944
 945        nf_log_register(NFPROTO_IPV4, &ipt_log_logger);
 946#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 947        nf_log_register(NFPROTO_IPV6, &ip6t_log_logger);
 948#endif
 949        return 0;
 950
 951err_target:
 952        unregister_pernet_subsys(&log_net_ops);
 953err_pernet:
 954        return ret;
 955}
 956
 957static void __exit log_tg_exit(void)
 958{
 959        unregister_pernet_subsys(&log_net_ops);
 960        nf_log_unregister(&ipt_log_logger);
 961#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 962        nf_log_unregister(&ip6t_log_logger);
 963#endif
 964        xt_unregister_targets(log_tg_regs, ARRAY_SIZE(log_tg_regs));
 965}
 966
 967module_init(log_tg_init);
 968module_exit(log_tg_exit);
 969
 970MODULE_LICENSE("GPL");
 971MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
 972MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
 973MODULE_DESCRIPTION("Xtables: IPv4/IPv6 packet logging");
 974MODULE_ALIAS("ipt_LOG");
 975MODULE_ALIAS("ip6t_LOG");
 976
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