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                sb_add(m, "UID=%u GID=%u ",
 156                        sk->sk_socket->file->f_cred->fsuid,
 157                        sk->sk_socket->file->f_cred->fsgid);
 158        read_unlock_bh(&sk->sk_callback_lock);
 159}
 160
 161/* One level of recursion won't kill us */
 162static void dump_ipv4_packet(struct sbuff *m,
 163                        const struct nf_loginfo *info,
 164                        const struct sk_buff *skb,
 165                        unsigned int iphoff)
 166{
 167        struct iphdr _iph;
 168        const struct iphdr *ih;
 169        unsigned int logflags;
 170
 171        if (info->type == NF_LOG_TYPE_LOG)
 172                logflags = info->u.log.logflags;
 173        else
 174                logflags = NF_LOG_MASK;
 175
 176        ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph);
 177        if (ih == NULL) {
 178                sb_add(m, "TRUNCATED");
 179                return;
 180        }
 181
 182        /* Important fields:
 183         * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */
 184        /* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */
 185        sb_add(m, "SRC=%pI4 DST=%pI4 ",
 186               &ih->saddr, &ih->daddr);
 187
 188        /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
 189        sb_add(m, "LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ",
 190               ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK,
 191               ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id));
 192
 193        /* Max length: 6 "CE DF MF " */
 194        if (ntohs(ih->frag_off) & IP_CE)
 195                sb_add(m, "CE ");
 196        if (ntohs(ih->frag_off) & IP_DF)
 197                sb_add(m, "DF ");
 198        if (ntohs(ih->frag_off) & IP_MF)
 199                sb_add(m, "MF ");
 200
 201        /* Max length: 11 "FRAG:65535 " */
 202        if (ntohs(ih->frag_off) & IP_OFFSET)
 203                sb_add(m, "FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);
 204
 205        if ((logflags & XT_LOG_IPOPT) &&
 206            ih->ihl * 4 > sizeof(struct iphdr)) {
 207                const unsigned char *op;
 208                unsigned char _opt[4 * 15 - sizeof(struct iphdr)];
 209                unsigned int i, optsize;
 210
 211                optsize = ih->ihl * 4 - sizeof(struct iphdr);
 212                op = skb_header_pointer(skb, iphoff+sizeof(_iph),
 213                                        optsize, _opt);
 214                if (op == NULL) {
 215                        sb_add(m, "TRUNCATED");
 216                        return;
 217                }
 218
 219                /* Max length: 127 "OPT (" 15*4*2chars ") " */
 220                sb_add(m, "OPT (");
 221                for (i = 0; i < optsize; i++)
 222                        sb_add(m, "%02X", op[i]);
 223                sb_add(m, ") ");
 224        }
 225
 226        switch (ih->protocol) {
 227        case IPPROTO_TCP:
 228                if (dump_tcp_header(m, skb, ih->protocol,
 229                                    ntohs(ih->frag_off) & IP_OFFSET,
 230                                    iphoff+ih->ihl*4, logflags))
 231                        return;
 232                break;
 233        case IPPROTO_UDP:
 234        case IPPROTO_UDPLITE:
 235                if (dump_udp_header(m, skb, ih->protocol,
 236                                    ntohs(ih->frag_off) & IP_OFFSET,
 237                                    iphoff+ih->ihl*4))
 238                        return;
 239                break;
 240        case IPPROTO_ICMP: {
 241                struct icmphdr _icmph;
 242                const struct icmphdr *ich;
 243                static const size_t required_len[NR_ICMP_TYPES+1]
 244                        = { [ICMP_ECHOREPLY] = 4,
 245                            [ICMP_DEST_UNREACH]
 246                            = 8 + sizeof(struct iphdr),
 247                            [ICMP_SOURCE_QUENCH]
 248                            = 8 + sizeof(struct iphdr),
 249                            [ICMP_REDIRECT]
 250                            = 8 + sizeof(struct iphdr),
 251                            [ICMP_ECHO] = 4,
 252                            [ICMP_TIME_EXCEEDED]
 253                            = 8 + sizeof(struct iphdr),
 254                            [ICMP_PARAMETERPROB]
 255                            = 8 + sizeof(struct iphdr),
 256                            [ICMP_TIMESTAMP] = 20,
 257                            [ICMP_TIMESTAMPREPLY] = 20,
 258                            [ICMP_ADDRESS] = 12,
 259                            [ICMP_ADDRESSREPLY] = 12 };
 260
 261                /* Max length: 11 "PROTO=ICMP " */
 262                sb_add(m, "PROTO=ICMP ");
 263
 264                if (ntohs(ih->frag_off) & IP_OFFSET)
 265                        break;
 266
 267                /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 268                ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
 269                                         sizeof(_icmph), &_icmph);
 270                if (ich == NULL) {
 271                        sb_add(m, "INCOMPLETE [%u bytes] ",
 272                               skb->len - iphoff - ih->ihl*4);
 273                        break;
 274                }
 275
 276                /* Max length: 18 "TYPE=255 CODE=255 " */
 277                sb_add(m, "TYPE=%u CODE=%u ", ich->type, ich->code);
 278
 279                /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 280                if (ich->type <= NR_ICMP_TYPES &&
 281                    required_len[ich->type] &&
 282                    skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) {
 283                        sb_add(m, "INCOMPLETE [%u bytes] ",
 284                               skb->len - iphoff - ih->ihl*4);
 285                        break;
 286                }
 287
 288                switch (ich->type) {
 289                case ICMP_ECHOREPLY:
 290                case ICMP_ECHO:
 291                        /* Max length: 19 "ID=65535 SEQ=65535 " */
 292                        sb_add(m, "ID=%u SEQ=%u ",
 293                               ntohs(ich->un.echo.id),
 294                               ntohs(ich->un.echo.sequence));
 295                        break;
 296
 297                case ICMP_PARAMETERPROB:
 298                        /* Max length: 14 "PARAMETER=255 " */
 299                        sb_add(m, "PARAMETER=%u ",
 300                               ntohl(ich->un.gateway) >> 24);
 301                        break;
 302                case ICMP_REDIRECT:
 303                        /* Max length: 24 "GATEWAY=255.255.255.255 " */
 304                        sb_add(m, "GATEWAY=%pI4 ", &ich->un.gateway);
 305                        /* Fall through */
 306                case ICMP_DEST_UNREACH:
 307                case ICMP_SOURCE_QUENCH:
 308                case ICMP_TIME_EXCEEDED:
 309                        /* Max length: 3+maxlen */
 310                        if (!iphoff) { /* Only recurse once. */
 311                                sb_add(m, "[");
 312                                dump_ipv4_packet(m, info, skb,
 313                                            iphoff + ih->ihl*4+sizeof(_icmph));
 314                                sb_add(m, "] ");
 315                        }
 316
 317                        /* Max length: 10 "MTU=65535 " */
 318                        if (ich->type == ICMP_DEST_UNREACH &&
 319                            ich->code == ICMP_FRAG_NEEDED)
 320                                sb_add(m, "MTU=%u ", ntohs(ich->un.frag.mtu));
 321                }
 322                break;
 323        }
 324        /* Max Length */
 325        case IPPROTO_AH: {
 326                struct ip_auth_hdr _ahdr;
 327                const struct ip_auth_hdr *ah;
 328
 329                if (ntohs(ih->frag_off) & IP_OFFSET)
 330                        break;
 331
 332                /* Max length: 9 "PROTO=AH " */
 333                sb_add(m, "PROTO=AH ");
 334
 335                /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 336                ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
 337                                        sizeof(_ahdr), &_ahdr);
 338                if (ah == NULL) {
 339                        sb_add(m, "INCOMPLETE [%u bytes] ",
 340                               skb->len - iphoff - ih->ihl*4);
 341                        break;
 342                }
 343
 344                /* Length: 15 "SPI=0xF1234567 " */
 345                sb_add(m, "SPI=0x%x ", ntohl(ah->spi));
 346                break;
 347        }
 348        case IPPROTO_ESP: {
 349                struct ip_esp_hdr _esph;
 350                const struct ip_esp_hdr *eh;
 351
 352                /* Max length: 10 "PROTO=ESP " */
 353                sb_add(m, "PROTO=ESP ");
 354
 355                if (ntohs(ih->frag_off) & IP_OFFSET)
 356                        break;
 357
 358                /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 359                eh = skb_header_pointer(skb, iphoff+ih->ihl*4,
 360                                        sizeof(_esph), &_esph);
 361                if (eh == NULL) {
 362                        sb_add(m, "INCOMPLETE [%u bytes] ",
 363                               skb->len - iphoff - ih->ihl*4);
 364                        break;
 365                }
 366
 367                /* Length: 15 "SPI=0xF1234567 " */
 368                sb_add(m, "SPI=0x%x ", ntohl(eh->spi));
 369                break;
 370        }
 371        /* Max length: 10 "PROTO 255 " */
 372        default:
 373                sb_add(m, "PROTO=%u ", ih->protocol);
 374        }
 375
 376        /* Max length: 15 "UID=4294967295 " */
 377        if ((logflags & XT_LOG_UID) && !iphoff)
 378                dump_sk_uid_gid(m, skb->sk);
 379
 380        /* Max length: 16 "MARK=0xFFFFFFFF " */
 381        if (!iphoff && skb->mark)
 382                sb_add(m, "MARK=0x%x ", skb->mark);
 383
 384        /* Proto    Max log string length */
 385        /* IP:      40+46+6+11+127 = 230 */
 386        /* TCP:     10+max(25,20+30+13+9+32+11+127) = 252 */
 387        /* UDP:     10+max(25,20) = 35 */
 388        /* UDPLITE: 14+max(25,20) = 39 */
 389        /* ICMP:    11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */
 390        /* ESP:     10+max(25)+15 = 50 */
 391        /* AH:      9+max(25)+15 = 49 */
 392        /* unknown: 10 */
 393
 394        /* (ICMP allows recursion one level deep) */
 395        /* maxlen =  IP + ICMP +  IP + max(TCP,UDP,ICMP,unknown) */
 396        /* maxlen = 230+   91  + 230 + 252 = 803 */
 397}
 398
 399static void dump_ipv4_mac_header(struct sbuff *m,
 400                            const struct nf_loginfo *info,
 401                            const struct sk_buff *skb)
 402{
 403        struct net_device *dev = skb->dev;
 404        unsigned int logflags = 0;
 405
 406        if (info->type == NF_LOG_TYPE_LOG)
 407                logflags = info->u.log.logflags;
 408
 409        if (!(logflags & XT_LOG_MACDECODE))
 410                goto fallback;
 411
 412        switch (dev->type) {
 413        case ARPHRD_ETHER:
 414                sb_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ",
 415                       eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
 416                       ntohs(eth_hdr(skb)->h_proto));
 417                return;
 418        default:
 419                break;
 420        }
 421
 422fallback:
 423        sb_add(m, "MAC=");
 424        if (dev->hard_header_len &&
 425            skb->mac_header != skb->network_header) {
 426                const unsigned char *p = skb_mac_header(skb);
 427                unsigned int i;
 428
 429                sb_add(m, "%02x", *p++);
 430                for (i = 1; i < dev->hard_header_len; i++, p++)
 431                        sb_add(m, ":%02x", *p);
 432        }
 433        sb_add(m, " ");
 434}
 435
 436static void
 437log_packet_common(struct sbuff *m,
 438                  u_int8_t pf,
 439                  unsigned int hooknum,
 440                  const struct sk_buff *skb,
 441                  const struct net_device *in,
 442                  const struct net_device *out,
 443                  const struct nf_loginfo *loginfo,
 444                  const char *prefix)
 445{
 446        sb_add(m, KERN_SOH "%c%sIN=%s OUT=%s ",
 447               '0' + loginfo->u.log.level, prefix,
 448               in ? in->name : "",
 449               out ? out->name : "");
 450#ifdef CONFIG_BRIDGE_NETFILTER
 451        if (skb->nf_bridge) {
 452                const struct net_device *physindev;
 453                const struct net_device *physoutdev;
 454
 455                physindev = skb->nf_bridge->physindev;
 456                if (physindev && in != physindev)
 457                        sb_add(m, "PHYSIN=%s ", physindev->name);
 458                physoutdev = skb->nf_bridge->physoutdev;
 459                if (physoutdev && out != physoutdev)
 460                        sb_add(m, "PHYSOUT=%s ", physoutdev->name);
 461        }
 462#endif
 463}
 464
 465
 466static void
 467ipt_log_packet(u_int8_t pf,
 468               unsigned int hooknum,
 469               const struct sk_buff *skb,
 470               const struct net_device *in,
 471               const struct net_device *out,
 472               const struct nf_loginfo *loginfo,
 473               const char *prefix)
 474{
 475        struct sbuff *m = sb_open();
 476
 477        if (!loginfo)
 478                loginfo = &default_loginfo;
 479
 480        log_packet_common(m, pf, hooknum, skb, in, out, loginfo, prefix);
 481
 482        if (in != NULL)
 483                dump_ipv4_mac_header(m, loginfo, skb);
 484
 485        dump_ipv4_packet(m, loginfo, skb, 0);
 486
 487        sb_close(m);
 488}
 489
 490#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 491/* One level of recursion won't kill us */
 492static void dump_ipv6_packet(struct sbuff *m,
 493                        const struct nf_loginfo *info,
 494                        const struct sk_buff *skb, unsigned int ip6hoff,
 495                        int recurse)
 496{
 497        u_int8_t currenthdr;
 498        int fragment;
 499        struct ipv6hdr _ip6h;
 500        const struct ipv6hdr *ih;
 501        unsigned int ptr;
 502        unsigned int hdrlen = 0;
 503        unsigned int logflags;
 504
 505        if (info->type == NF_LOG_TYPE_LOG)
 506                logflags = info->u.log.logflags;
 507        else
 508                logflags = NF_LOG_MASK;
 509
 510        ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
 511        if (ih == NULL) {
 512                sb_add(m, "TRUNCATED");
 513                return;
 514        }
 515
 516        /* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
 517        sb_add(m, "SRC=%pI6 DST=%pI6 ", &ih->saddr, &ih->daddr);
 518
 519        /* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
 520        sb_add(m, "LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
 521               ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
 522               (ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20,
 523               ih->hop_limit,
 524               (ntohl(*(__be32 *)ih) & 0x000fffff));
 525
 526        fragment = 0;
 527        ptr = ip6hoff + sizeof(struct ipv6hdr);
 528        currenthdr = ih->nexthdr;
 529        while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
 530                struct ipv6_opt_hdr _hdr;
 531                const struct ipv6_opt_hdr *hp;
 532
 533                hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
 534                if (hp == NULL) {
 535                        sb_add(m, "TRUNCATED");
 536                        return;
 537                }
 538
 539                /* Max length: 48 "OPT (...) " */
 540                if (logflags & XT_LOG_IPOPT)
 541                        sb_add(m, "OPT ( ");
 542
 543                switch (currenthdr) {
 544                case IPPROTO_FRAGMENT: {
 545                        struct frag_hdr _fhdr;
 546                        const struct frag_hdr *fh;
 547
 548                        sb_add(m, "FRAG:");
 549                        fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
 550                                                &_fhdr);
 551                        if (fh == NULL) {
 552                                sb_add(m, "TRUNCATED ");
 553                                return;
 554                        }
 555
 556                        /* Max length: 6 "65535 " */
 557                        sb_add(m, "%u ", ntohs(fh->frag_off) & 0xFFF8);
 558
 559                        /* Max length: 11 "INCOMPLETE " */
 560                        if (fh->frag_off & htons(0x0001))
 561                                sb_add(m, "INCOMPLETE ");
 562
 563                        sb_add(m, "ID:%08x ", ntohl(fh->identification));
 564
 565                        if (ntohs(fh->frag_off) & 0xFFF8)
 566                                fragment = 1;
 567
 568                        hdrlen = 8;
 569
 570                        break;
 571                }
 572                case IPPROTO_DSTOPTS:
 573                case IPPROTO_ROUTING:
 574                case IPPROTO_HOPOPTS:
 575                        if (fragment) {
 576                                if (logflags & XT_LOG_IPOPT)
 577                                        sb_add(m, ")");
 578                                return;
 579                        }
 580                        hdrlen = ipv6_optlen(hp);
 581                        break;
 582                /* Max Length */
 583                case IPPROTO_AH:
 584                        if (logflags & XT_LOG_IPOPT) {
 585                                struct ip_auth_hdr _ahdr;
 586                                const struct ip_auth_hdr *ah;
 587
 588                                /* Max length: 3 "AH " */
 589                                sb_add(m, "AH ");
 590
 591                                if (fragment) {
 592                                        sb_add(m, ")");
 593                                        return;
 594                                }
 595
 596                                ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
 597                                                        &_ahdr);
 598                                if (ah == NULL) {
 599                                        /*
 600                                         * Max length: 26 "INCOMPLETE [65535
 601                                         *  bytes] )"
 602                                         */
 603                                        sb_add(m, "INCOMPLETE [%u bytes] )",
 604                                               skb->len - ptr);
 605                                        return;
 606                                }
 607
 608                                /* Length: 15 "SPI=0xF1234567 */
 609                                sb_add(m, "SPI=0x%x ", ntohl(ah->spi));
 610
 611                        }
 612
 613                        hdrlen = (hp->hdrlen+2)<<2;
 614                        break;
 615                case IPPROTO_ESP:
 616                        if (logflags & XT_LOG_IPOPT) {
 617                                struct ip_esp_hdr _esph;
 618                                const struct ip_esp_hdr *eh;
 619
 620                                /* Max length: 4 "ESP " */
 621                                sb_add(m, "ESP ");
 622
 623                                if (fragment) {
 624                                        sb_add(m, ")");
 625                                        return;
 626                                }
 627
 628                                /*
 629                                 * Max length: 26 "INCOMPLETE [65535 bytes] )"
 630                                 */
 631                                eh = skb_header_pointer(skb, ptr, sizeof(_esph),
 632                                                        &_esph);
 633                                if (eh == NULL) {
 634                                        sb_add(m, "INCOMPLETE [%u bytes] )",
 635                                               skb->len - ptr);
 636                                        return;
 637                                }
 638
 639                                /* Length: 16 "SPI=0xF1234567 )" */
 640                                sb_add(m, "SPI=0x%x )", ntohl(eh->spi));
 641
 642                        }
 643                        return;
 644                default:
 645                        /* Max length: 20 "Unknown Ext Hdr 255" */
 646                        sb_add(m, "Unknown Ext Hdr %u", currenthdr);
 647                        return;
 648                }
 649                if (logflags & XT_LOG_IPOPT)
 650                        sb_add(m, ") ");
 651
 652                currenthdr = hp->nexthdr;
 653                ptr += hdrlen;
 654        }
 655
 656        switch (currenthdr) {
 657        case IPPROTO_TCP:
 658                if (dump_tcp_header(m, skb, currenthdr, fragment, ptr,
 659                    logflags))
 660                        return;
 661                break;
 662        case IPPROTO_UDP:
 663        case IPPROTO_UDPLITE:
 664                if (dump_udp_header(m, skb, currenthdr, fragment, ptr))
 665                        return;
 666                break;
 667        case IPPROTO_ICMPV6: {
 668                struct icmp6hdr _icmp6h;
 669                const struct icmp6hdr *ic;
 670
 671                /* Max length: 13 "PROTO=ICMPv6 " */
 672                sb_add(m, "PROTO=ICMPv6 ");
 673
 674                if (fragment)
 675                        break;
 676
 677                /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 678                ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
 679                if (ic == NULL) {
 680                        sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - ptr);
 681                        return;
 682                }
 683
 684                /* Max length: 18 "TYPE=255 CODE=255 " */
 685                sb_add(m, "TYPE=%u CODE=%u ", ic->icmp6_type, ic->icmp6_code);
 686
 687                switch (ic->icmp6_type) {
 688                case ICMPV6_ECHO_REQUEST:
 689                case ICMPV6_ECHO_REPLY:
 690                        /* Max length: 19 "ID=65535 SEQ=65535 " */
 691                        sb_add(m, "ID=%u SEQ=%u ",
 692                                ntohs(ic->icmp6_identifier),
 693                                ntohs(ic->icmp6_sequence));
 694                        break;
 695                case ICMPV6_MGM_QUERY:
 696                case ICMPV6_MGM_REPORT:
 697                case ICMPV6_MGM_REDUCTION:
 698                        break;
 699
 700                case ICMPV6_PARAMPROB:
 701                        /* Max length: 17 "POINTER=ffffffff " */
 702                        sb_add(m, "POINTER=%08x ", ntohl(ic->icmp6_pointer));
 703                        /* Fall through */
 704                case ICMPV6_DEST_UNREACH:
 705                case ICMPV6_PKT_TOOBIG:
 706                case ICMPV6_TIME_EXCEED:
 707                        /* Max length: 3+maxlen */
 708                        if (recurse) {
 709                                sb_add(m, "[");
 710                                dump_ipv6_packet(m, info, skb,
 711                                            ptr + sizeof(_icmp6h), 0);
 712                                sb_add(m, "] ");
 713                        }
 714
 715                        /* Max length: 10 "MTU=65535 " */
 716                        if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
 717                                sb_add(m, "MTU=%u ", ntohl(ic->icmp6_mtu));
 718                }
 719                break;
 720        }
 721        /* Max length: 10 "PROTO=255 " */
 722        default:
 723                sb_add(m, "PROTO=%u ", currenthdr);
 724        }
 725
 726        /* Max length: 15 "UID=4294967295 " */
 727        if ((logflags & XT_LOG_UID) && recurse)
 728                dump_sk_uid_gid(m, skb->sk);
 729
 730        /* Max length: 16 "MARK=0xFFFFFFFF " */
 731        if (!recurse && skb->mark)
 732                sb_add(m, "MARK=0x%x ", skb->mark);
 733}
 734
 735static void dump_ipv6_mac_header(struct sbuff *m,
 736                            const struct nf_loginfo *info,
 737                            const struct sk_buff *skb)
 738{
 739        struct net_device *dev = skb->dev;
 740        unsigned int logflags = 0;
 741
 742        if (info->type == NF_LOG_TYPE_LOG)
 743                logflags = info->u.log.logflags;
 744
 745        if (!(logflags & XT_LOG_MACDECODE))
 746                goto fallback;
 747
 748        switch (dev->type) {
 749        case ARPHRD_ETHER:
 750                sb_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ",
 751                       eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
 752                       ntohs(eth_hdr(skb)->h_proto));
 753                return;
 754        default:
 755                break;
 756        }
 757
 758fallback:
 759        sb_add(m, "MAC=");
 760        if (dev->hard_header_len &&
 761            skb->mac_header != skb->network_header) {
 762                const unsigned char *p = skb_mac_header(skb);
 763                unsigned int len = dev->hard_header_len;
 764                unsigned int i;
 765
 766                if (dev->type == ARPHRD_SIT) {
 767                        p -= ETH_HLEN;
 768
 769                        if (p < skb->head)
 770                                p = NULL;
 771                }
 772
 773                if (p != NULL) {
 774                        sb_add(m, "%02x", *p++);
 775                        for (i = 1; i < len; i++)
 776                                sb_add(m, ":%02x", *p++);
 777                }
 778                sb_add(m, " ");
 779
 780                if (dev->type == ARPHRD_SIT) {
 781                        const struct iphdr *iph =
 782                                (struct iphdr *)skb_mac_header(skb);
 783                        sb_add(m, "TUNNEL=%pI4->%pI4 ", &iph->saddr,
 784                               &iph->daddr);
 785                }
 786        } else
 787                sb_add(m, " ");
 788}
 789
 790static void
 791ip6t_log_packet(u_int8_t pf,
 792                unsigned int hooknum,
 793                const struct sk_buff *skb,
 794                const struct net_device *in,
 795                const struct net_device *out,
 796                const struct nf_loginfo *loginfo,
 797                const char *prefix)
 798{
 799        struct sbuff *m = sb_open();
 800
 801        if (!loginfo)
 802                loginfo = &default_loginfo;
 803
 804        log_packet_common(m, pf, hooknum, skb, in, out, loginfo, prefix);
 805
 806        if (in != NULL)
 807                dump_ipv6_mac_header(m, loginfo, skb);
 808
 809        dump_ipv6_packet(m, loginfo, skb, skb_network_offset(skb), 1);
 810
 811        sb_close(m);
 812}
 813#endif
 814
 815static unsigned int
 816log_tg(struct sk_buff *skb, const struct xt_action_param *par)
 817{
 818        const struct xt_log_info *loginfo = par->targinfo;
 819        struct nf_loginfo li;
 820
 821        li.type = NF_LOG_TYPE_LOG;
 822        li.u.log.level = loginfo->level;
 823        li.u.log.logflags = loginfo->logflags;
 824
 825        if (par->family == NFPROTO_IPV4)
 826                ipt_log_packet(NFPROTO_IPV4, par->hooknum, skb, par->in,
 827                               par->out, &li, loginfo->prefix);
 828#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 829        else if (par->family == NFPROTO_IPV6)
 830                ip6t_log_packet(NFPROTO_IPV6, par->hooknum, skb, par->in,
 831                                par->out, &li, loginfo->prefix);
 832#endif
 833        else
 834                WARN_ON_ONCE(1);
 835
 836        return XT_CONTINUE;
 837}
 838
 839static int log_tg_check(const struct xt_tgchk_param *par)
 840{
 841        const struct xt_log_info *loginfo = par->targinfo;
 842
 843        if (par->family != NFPROTO_IPV4 && par->family != NFPROTO_IPV6)
 844                return -EINVAL;
 845
 846        if (loginfo->level >= 8) {
 847                pr_debug("level %u >= 8\n", loginfo->level);
 848                return -EINVAL;
 849        }
 850
 851        if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
 852                pr_debug("prefix is not null-terminated\n");
 853                return -EINVAL;
 854        }
 855
 856        return 0;
 857}
 858
 859static struct xt_target log_tg_regs[] __read_mostly = {
 860        {
 861                .name           = "LOG",
 862                .family         = NFPROTO_IPV4,
 863                .target         = log_tg,
 864                .targetsize     = sizeof(struct xt_log_info),
 865                .checkentry     = log_tg_check,
 866                .me             = THIS_MODULE,
 867        },
 868#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 869        {
 870                .name           = "LOG",
 871                .family         = NFPROTO_IPV6,
 872                .target         = log_tg,
 873                .targetsize     = sizeof(struct xt_log_info),
 874                .checkentry     = log_tg_check,
 875                .me             = THIS_MODULE,
 876        },
 877#endif
 878};
 879
 880static struct nf_logger ipt_log_logger __read_mostly = {
 881        .name           = "ipt_LOG",
 882        .logfn          = &ipt_log_packet,
 883        .me             = THIS_MODULE,
 884};
 885
 886#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 887static struct nf_logger ip6t_log_logger __read_mostly = {
 888        .name           = "ip6t_LOG",
 889        .logfn          = &ip6t_log_packet,
 890        .me             = THIS_MODULE,
 891};
 892#endif
 893
 894static int __init log_tg_init(void)
 895{
 896        int ret;
 897
 898        ret = xt_register_targets(log_tg_regs, ARRAY_SIZE(log_tg_regs));
 899        if (ret < 0)
 900                return ret;
 901
 902        nf_log_register(NFPROTO_IPV4, &ipt_log_logger);
 903#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 904        nf_log_register(NFPROTO_IPV6, &ip6t_log_logger);
 905#endif
 906        return 0;
 907}
 908
 909static void __exit log_tg_exit(void)
 910{
 911        nf_log_unregister(&ipt_log_logger);
 912#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 913        nf_log_unregister(&ip6t_log_logger);
 914#endif
 915        xt_unregister_targets(log_tg_regs, ARRAY_SIZE(log_tg_regs));
 916}
 917
 918module_init(log_tg_init);
 919module_exit(log_tg_exit);
 920
 921MODULE_LICENSE("GPL");
 922MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
 923MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
 924MODULE_DESCRIPTION("Xtables: IPv4/IPv6 packet logging");
 925MODULE_ALIAS("ipt_LOG");
 926MODULE_ALIAS("ip6t_LOG");
 927
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