net/netfilter/nf_conntrack_proto_sctp.c

   1 /*
   2  * Connection tracking protocol helper module for SCTP.
   3  *
   4  * Copyright (c) 2004 Kiran Kumar Immidi <immidi_kiran@yahoo.com>
   5  * Copyright (c) 2004-2012 Patrick McHardy <kaber@trash.net>
   6  *
   7  * SCTP is defined in RFC 2960. References to various sections in this code
   8  * are to this RFC.
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14
  15 #include <linux/types.h>
  16 #include <linux/timer.h>
  17 #include <linux/netfilter.h>
  18 #include <linux/in.h>
  19 #include <linux/ip.h>
  20 #include <linux/sctp.h>
  21 #include <linux/string.h>
  22 #include <linux/seq_file.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/interrupt.h>
  25 #include <net/sctp/checksum.h>
  26
  27 #include <net/netfilter/nf_log.h>
  28 #include <net/netfilter/nf_conntrack.h>
  29 #include <net/netfilter/nf_conntrack_l4proto.h>
  30 #include <net/netfilter/nf_conntrack_ecache.h>
  31 #include <net/netfilter/nf_conntrack_timeout.h>
  32
  33 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
  34    closely.  They're more complex. --RR
  35
  36    And so for me for SCTP :D -Kiran */
  37
  38 static const char *const sctp_conntrack_names[] = {
  39         "NONE",
  40         "CLOSED",
  41         "COOKIE_WAIT",
  42         "COOKIE_ECHOED",
  43         "ESTABLISHED",
  44         "SHUTDOWN_SENT",
  45         "SHUTDOWN_RECD",
  46         "SHUTDOWN_ACK_SENT",
  47         "HEARTBEAT_SENT",
  48         "HEARTBEAT_ACKED",
  49 };
  50
  51 #define SECS  * HZ
  52 #define MINS  * 60 SECS
  53 #define HOURS * 60 MINS
  54 #define DAYS  * 24 HOURS
  55
  56 static const unsigned int sctp_timeouts[SCTP_CONNTRACK_MAX] = {
  57         [SCTP_CONNTRACK_CLOSED]                 = 10 SECS,
  58         [SCTP_CONNTRACK_COOKIE_WAIT]            = 3 SECS,
  59         [SCTP_CONNTRACK_COOKIE_ECHOED]          = 3 SECS,
  60         [SCTP_CONNTRACK_ESTABLISHED]            = 5 DAYS,
  61         [SCTP_CONNTRACK_SHUTDOWN_SENT]          = 300 SECS / 1000,
  62         [SCTP_CONNTRACK_SHUTDOWN_RECD]          = 300 SECS / 1000,
  63         [SCTP_CONNTRACK_SHUTDOWN_ACK_SENT]      = 3 SECS,
  64         [SCTP_CONNTRACK_HEARTBEAT_SENT]         = 30 SECS,
  65         [SCTP_CONNTRACK_HEARTBEAT_ACKED]        = 210 SECS,
  66 };
  67
  68 #define SCTP_FLAG_HEARTBEAT_VTAG_FAILED 1
  69
  70 #define sNO SCTP_CONNTRACK_NONE
  71 #define sCL SCTP_CONNTRACK_CLOSED
  72 #define sCW SCTP_CONNTRACK_COOKIE_WAIT
  73 #define sCE SCTP_CONNTRACK_COOKIE_ECHOED
  74 #define sES SCTP_CONNTRACK_ESTABLISHED
  75 #define sSS SCTP_CONNTRACK_SHUTDOWN_SENT
  76 #define sSR SCTP_CONNTRACK_SHUTDOWN_RECD
  77 #define sSA SCTP_CONNTRACK_SHUTDOWN_ACK_SENT
  78 #define sHS SCTP_CONNTRACK_HEARTBEAT_SENT
  79 #define sHA SCTP_CONNTRACK_HEARTBEAT_ACKED
  80 #define sIV SCTP_CONNTRACK_MAX
  81
  82 /*
  83         These are the descriptions of the states:
  84
  85 NOTE: These state names are tantalizingly similar to the states of an
  86 SCTP endpoint. But the interpretation of the states is a little different,
  87 considering that these are the states of the connection and not of an end
  88 point. Please note the subtleties. -Kiran
  89
  90 NONE              - Nothing so far.
  91 COOKIE WAIT       - We have seen an INIT chunk in the original direction, or also
  92                     an INIT_ACK chunk in the reply direction.
  93 COOKIE ECHOED     - We have seen a COOKIE_ECHO chunk in the original direction.
  94 ESTABLISHED       - We have seen a COOKIE_ACK in the reply direction.
  95 SHUTDOWN_SENT     - We have seen a SHUTDOWN chunk in the original direction.
  96 SHUTDOWN_RECD     - We have seen a SHUTDOWN chunk in the reply directoin.
  97 SHUTDOWN_ACK_SENT - We have seen a SHUTDOWN_ACK chunk in the direction opposite
  98                     to that of the SHUTDOWN chunk.
  99 CLOSED            - We have seen a SHUTDOWN_COMPLETE chunk in the direction of
 100                     the SHUTDOWN chunk. Connection is closed.
 101 HEARTBEAT_SENT    - We have seen a HEARTBEAT in a new flow.
 102 HEARTBEAT_ACKED   - We have seen a HEARTBEAT-ACK in the direction opposite to
 103                     that of the HEARTBEAT chunk. Secondary connection is
 104                     established.
 105 */
 106
 107 /* TODO
 108  - I have assumed that the first INIT is in the original direction.
 109  This messes things when an INIT comes in the reply direction in CLOSED
 110  state.
 111  - Check the error type in the reply dir before transitioning from
 112 cookie echoed to closed.
 113  - Sec 5.2.4 of RFC 2960
 114  - Full Multi Homing support.
 115 */
 116
 117 /* SCTP conntrack state transitions */
 118 static const u8 sctp_conntracks[2][11][SCTP_CONNTRACK_MAX] = {
 119         {
 120 /*      ORIGINAL        */
 121 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA */
 122 /* init         */ {sCW, sCW, sCW, sCE, sES, sSS, sSR, sSA, sCW, sHA},
 123 /* init_ack     */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA},
 124 /* abort        */ {sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
 125 /* shutdown     */ {sCL, sCL, sCW, sCE, sSS, sSS, sSR, sSA, sCL, sSS},
 126 /* shutdown_ack */ {sSA, sCL, sCW, sCE, sES, sSA, sSA, sSA, sSA, sHA},
 127 /* error        */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA},/* Can't have Stale cookie*/
 128 /* cookie_echo  */ {sCL, sCL, sCE, sCE, sES, sSS, sSR, sSA, sCL, sHA},/* 5.2.4 - Big TODO */
 129 /* cookie_ack   */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA},/* Can't come in orig dir */
 130 /* shutdown_comp*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sCL, sCL, sHA},
 131 /* heartbeat    */ {sHS, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA},
 132 /* heartbeat_ack*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA}
 133         },
 134         {
 135 /*      REPLY   */
 136 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA */
 137 /* init         */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},/* INIT in sCL Big TODO */
 138 /* init_ack     */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},
 139 /* abort        */ {sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV, sCL},
 140 /* shutdown     */ {sIV, sCL, sCW, sCE, sSR, sSS, sSR, sSA, sIV, sSR},
 141 /* shutdown_ack */ {sIV, sCL, sCW, sCE, sES, sSA, sSA, sSA, sIV, sHA},
 142 /* error        */ {sIV, sCL, sCW, sCL, sES, sSS, sSR, sSA, sIV, sHA},
 143 /* cookie_echo  */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},/* Can't come in reply dir */
 144 /* cookie_ack   */ {sIV, sCL, sCW, sES, sES, sSS, sSR, sSA, sIV, sHA},
 145 /* shutdown_comp*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sCL, sIV, sHA},
 146 /* heartbeat    */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA},
 147 /* heartbeat_ack*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHA, sHA}
 148         }
 149 };
 150
 151 static inline struct nf_sctp_net *sctp_pernet(struct net *net)
 152 {
 153         return &net->ct.nf_ct_proto.sctp;
 154 }
 155
 156 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 157 /* Print out the private part of the conntrack. */
 158 static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 159 {
 160         seq_printf(s, "%s ", sctp_conntrack_names[ct->proto.sctp.state]);
 161 }
 162 #endif
 163
 164 #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count)     \
 165 for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0;        \
 166         (offset) < (skb)->len &&                                        \
 167         ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch)));   \
 168         (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
 169
 170 /* Some validity checks to make sure the chunks are fine */
 171 static int do_basic_checks(struct nf_conn *ct,
 172                            const struct sk_buff *skb,
 173                            unsigned int dataoff,
 174                            unsigned long *map)
 175 {
 176         u_int32_t offset, count;
 177         struct sctp_chunkhdr _sch, *sch;
 178         int flag;
 179
 180         flag = 0;
 181
 182         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 183                 pr_debug("Chunk Num: %d  Type: %d\n", count, sch->type);
 184
 185                 if (sch->type == SCTP_CID_INIT ||
 186                     sch->type == SCTP_CID_INIT_ACK ||
 187                     sch->type == SCTP_CID_SHUTDOWN_COMPLETE)
 188                         flag = 1;
 189
 190                 /*
 191                  * Cookie Ack/Echo chunks not the first OR
 192                  * Init / Init Ack / Shutdown compl chunks not the only chunks
 193                  * OR zero-length.
 194                  */
 195                 if (((sch->type == SCTP_CID_COOKIE_ACK ||
 196                       sch->type == SCTP_CID_COOKIE_ECHO ||
 197                       flag) &&
 198                      count != 0) || !sch->length) {
 199                         pr_debug("Basic checks failed\n");
 200                         return 1;
 201                 }
 202
 203                 if (map)
 204                         set_bit(sch->type, map);
 205         }
 206
 207         pr_debug("Basic checks passed\n");
 208         return count == 0;
 209 }
 210
 211 static int sctp_new_state(enum ip_conntrack_dir dir,
 212                           enum sctp_conntrack cur_state,
 213                           int chunk_type)
 214 {
 215         int i;
 216
 217         pr_debug("Chunk type: %d\n", chunk_type);
 218
 219         switch (chunk_type) {
 220         case SCTP_CID_INIT:
 221                 pr_debug("SCTP_CID_INIT\n");
 222                 i = 0;
 223                 break;
 224         case SCTP_CID_INIT_ACK:
 225                 pr_debug("SCTP_CID_INIT_ACK\n");
 226                 i = 1;
 227                 break;
 228         case SCTP_CID_ABORT:
 229                 pr_debug("SCTP_CID_ABORT\n");
 230                 i = 2;
 231                 break;
 232         case SCTP_CID_SHUTDOWN:
 233                 pr_debug("SCTP_CID_SHUTDOWN\n");
 234                 i = 3;
 235                 break;
 236         case SCTP_CID_SHUTDOWN_ACK:
 237                 pr_debug("SCTP_CID_SHUTDOWN_ACK\n");
 238                 i = 4;
 239                 break;
 240         case SCTP_CID_ERROR:
 241                 pr_debug("SCTP_CID_ERROR\n");
 242                 i = 5;
 243                 break;
 244         case SCTP_CID_COOKIE_ECHO:
 245                 pr_debug("SCTP_CID_COOKIE_ECHO\n");
 246                 i = 6;
 247                 break;
 248         case SCTP_CID_COOKIE_ACK:
 249                 pr_debug("SCTP_CID_COOKIE_ACK\n");
 250                 i = 7;
 251                 break;
 252         case SCTP_CID_SHUTDOWN_COMPLETE:
 253                 pr_debug("SCTP_CID_SHUTDOWN_COMPLETE\n");
 254                 i = 8;
 255                 break;
 256         case SCTP_CID_HEARTBEAT:
 257                 pr_debug("SCTP_CID_HEARTBEAT");
 258                 i = 9;
 259                 break;
 260         case SCTP_CID_HEARTBEAT_ACK:
 261                 pr_debug("SCTP_CID_HEARTBEAT_ACK");
 262                 i = 10;
 263                 break;
 264         default:
 265                 /* Other chunks like DATA or SACK do not change the state */
 266                 pr_debug("Unknown chunk type, Will stay in %s\n",
 267                          sctp_conntrack_names[cur_state]);
 268                 return cur_state;
 269         }
 270
 271         pr_debug("dir: %d   cur_state: %s  chunk_type: %d  new_state: %s\n",
 272                  dir, sctp_conntrack_names[cur_state], chunk_type,
 273                  sctp_conntrack_names[sctp_conntracks[dir][i][cur_state]]);
 274
 275         return sctp_conntracks[dir][i][cur_state];
 276 }
 277
 278 /* Returns verdict for packet, or -NF_ACCEPT for invalid. */
 279 static int sctp_packet(struct nf_conn *ct,
 280                        const struct sk_buff *skb,
 281                        unsigned int dataoff,
 282                        enum ip_conntrack_info ctinfo)
 283 {
 284         enum sctp_conntrack new_state, old_state;
 285         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 286         const struct sctphdr *sh;
 287         struct sctphdr _sctph;
 288         const struct sctp_chunkhdr *sch;
 289         struct sctp_chunkhdr _sch;
 290         u_int32_t offset, count;
 291         unsigned int *timeouts;
 292         unsigned long map[256 / sizeof(unsigned long)] = { 0 };
 293         bool ignore = false;
 294
 295         sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
 296         if (sh == NULL)
 297                 goto out;
 298
 299         if (do_basic_checks(ct, skb, dataoff, map) != 0)
 300                 goto out;
 301
 302         /* Check the verification tag (Sec 8.5) */
 303         if (!test_bit(SCTP_CID_INIT, map) &&
 304             !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) &&
 305             !test_bit(SCTP_CID_COOKIE_ECHO, map) &&
 306             !test_bit(SCTP_CID_ABORT, map) &&
 307             !test_bit(SCTP_CID_SHUTDOWN_ACK, map) &&
 308             !test_bit(SCTP_CID_HEARTBEAT, map) &&
 309             !test_bit(SCTP_CID_HEARTBEAT_ACK, map) &&
 310             sh->vtag != ct->proto.sctp.vtag[dir]) {
 311                 pr_debug("Verification tag check failed\n");
 312                 goto out;
 313         }
 314
 315         old_state = new_state = SCTP_CONNTRACK_NONE;
 316         spin_lock_bh(&ct->lock);
 317         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 318                 /* Special cases of Verification tag check (Sec 8.5.1) */
 319                 if (sch->type == SCTP_CID_INIT) {
 320                         /* (A) vtag MUST be zero */
 321                         if (sh->vtag != 0)
 322                                 goto out_unlock;
 323                 } else if (sch->type == SCTP_CID_ABORT) {
 324                         /* (B) vtag MUST match own vtag if T flag is unset OR
 325                          * MUST match peer's vtag if T flag is set
 326                          */
 327                         if ((!(sch->flags & SCTP_CHUNK_FLAG_T) &&
 328                              sh->vtag != ct->proto.sctp.vtag[dir]) ||
 329                             ((sch->flags & SCTP_CHUNK_FLAG_T) &&
 330                              sh->vtag != ct->proto.sctp.vtag[!dir]))
 331                                 goto out_unlock;
 332                 } else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
 333                         /* (C) vtag MUST match own vtag if T flag is unset OR
 334                          * MUST match peer's vtag if T flag is set
 335                          */
 336                         if ((!(sch->flags & SCTP_CHUNK_FLAG_T) &&
 337                              sh->vtag != ct->proto.sctp.vtag[dir]) ||
 338                             ((sch->flags & SCTP_CHUNK_FLAG_T) &&
 339                              sh->vtag != ct->proto.sctp.vtag[!dir]))
 340                                 goto out_unlock;
 341                 } else if (sch->type == SCTP_CID_COOKIE_ECHO) {
 342                         /* (D) vtag must be same as init_vtag as found in INIT_ACK */
 343                         if (sh->vtag != ct->proto.sctp.vtag[dir])
 344                                 goto out_unlock;
 345                 } else if (sch->type == SCTP_CID_HEARTBEAT) {
 346                         if (ct->proto.sctp.vtag[dir] == 0) {
 347                                 pr_debug("Setting %d vtag %x for dir %d\n", sch->type, sh->vtag, dir);
 348                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 349                         } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
 350                                 if (test_bit(SCTP_CID_DATA, map) || ignore)
 351                                         goto out_unlock;
 352
 353                                 ct->proto.sctp.flags |= SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 354                                 ct->proto.sctp.last_dir = dir;
 355                                 ignore = true;
 356                                 continue;
 357                         } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) {
 358                                 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 359                         }
 360                 } else if (sch->type == SCTP_CID_HEARTBEAT_ACK) {
 361                         if (ct->proto.sctp.vtag[dir] == 0) {
 362                                 pr_debug("Setting vtag %x for dir %d\n",
 363                                          sh->vtag, dir);
 364                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 365                         } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
 366                                 if (test_bit(SCTP_CID_DATA, map) || ignore)
 367                                         goto out_unlock;
 368
 369                                 if ((ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) == 0 ||
 370                                     ct->proto.sctp.last_dir == dir)
 371                                         goto out_unlock;
 372
 373                                 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 374                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 375                                 ct->proto.sctp.vtag[!dir] = 0;
 376                         } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) {
 377                                 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 378                         }
 379                 }
 380
 381                 old_state = ct->proto.sctp.state;
 382                 new_state = sctp_new_state(dir, old_state, sch->type);
 383
 384                 /* Invalid */
 385                 if (new_state == SCTP_CONNTRACK_MAX) {
 386                         pr_debug("nf_conntrack_sctp: Invalid dir=%i ctype=%u "
 387                                  "conntrack=%u\n",
 388                                  dir, sch->type, old_state);
 389                         goto out_unlock;
 390                 }
 391
 392                 /* If it is an INIT or an INIT ACK note down the vtag */
 393                 if (sch->type == SCTP_CID_INIT ||
 394                     sch->type == SCTP_CID_INIT_ACK) {
 395                         struct sctp_inithdr _inithdr, *ih;
 396
 397                         ih = skb_header_pointer(skb, offset + sizeof(_sch),
 398                                                 sizeof(_inithdr), &_inithdr);
 399                         if (ih == NULL)
 400                                 goto out_unlock;
 401                         pr_debug("Setting vtag %x for dir %d\n",
 402                                  ih->init_tag, !dir);
 403                         ct->proto.sctp.vtag[!dir] = ih->init_tag;
 404
 405                         /* don't renew timeout on init retransmit so
 406                          * port reuse by client or NAT middlebox cannot
 407                          * keep entry alive indefinitely (incl. nat info).
 408                          */
 409                         if (new_state == SCTP_CONNTRACK_CLOSED &&
 410                             old_state == SCTP_CONNTRACK_CLOSED &&
 411                             nf_ct_is_confirmed(ct))
 412                                 ignore = true;
 413                 }
 414
 415                 ct->proto.sctp.state = new_state;
 416                 if (old_state != new_state)
 417                         nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
 418         }
 419         spin_unlock_bh(&ct->lock);
 420
 421         /* allow but do not refresh timeout */
 422         if (ignore)
 423                 return NF_ACCEPT;
 424
 425         timeouts = nf_ct_timeout_lookup(ct);
 426         if (!timeouts)
 427                 timeouts = sctp_pernet(nf_ct_net(ct))->timeouts;
 428
 429         nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);
 430
 431         if (old_state == SCTP_CONNTRACK_COOKIE_ECHOED &&
 432             dir == IP_CT_DIR_REPLY &&
 433             new_state == SCTP_CONNTRACK_ESTABLISHED) {
 434                 pr_debug("Setting assured bit\n");
 435                 set_bit(IPS_ASSURED_BIT, &ct->status);
 436                 nf_conntrack_event_cache(IPCT_ASSURED, ct);
 437         }
 438
 439         return NF_ACCEPT;
 440
 441 out_unlock:
 442         spin_unlock_bh(&ct->lock);
 443 out:
 444         return -NF_ACCEPT;
 445 }
 446
 447 /* Called when a new connection for this protocol found. */
 448 static bool sctp_new(struct nf_conn *ct, const struct sk_buff *skb,
 449                      unsigned int dataoff)
 450 {
 451         enum sctp_conntrack new_state;
 452         const struct sctphdr *sh;
 453         struct sctphdr _sctph;
 454         const struct sctp_chunkhdr *sch;
 455         struct sctp_chunkhdr _sch;
 456         u_int32_t offset, count;
 457         unsigned long map[256 / sizeof(unsigned long)] = { 0 };
 458
 459         sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
 460         if (sh == NULL)
 461                 return false;
 462
 463         if (do_basic_checks(ct, skb, dataoff, map) != 0)
 464                 return false;
 465
 466         /* If an OOTB packet has any of these chunks discard (Sec 8.4) */
 467         if (test_bit(SCTP_CID_ABORT, map) ||
 468             test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) ||
 469             test_bit(SCTP_CID_COOKIE_ACK, map))
 470                 return false;
 471
 472         memset(&ct->proto.sctp, 0, sizeof(ct->proto.sctp));
 473         new_state = SCTP_CONNTRACK_MAX;
 474         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 475                 /* Don't need lock here: this conntrack not in circulation yet */
 476                 new_state = sctp_new_state(IP_CT_DIR_ORIGINAL,
 477                                            SCTP_CONNTRACK_NONE, sch->type);
 478
 479                 /* Invalid: delete conntrack */
 480                 if (new_state == SCTP_CONNTRACK_NONE ||
 481                     new_state == SCTP_CONNTRACK_MAX) {
 482                         pr_debug("nf_conntrack_sctp: invalid new deleting.\n");
 483                         return false;
 484                 }
 485
 486                 /* Copy the vtag into the state info */
 487                 if (sch->type == SCTP_CID_INIT) {
 488                         struct sctp_inithdr _inithdr, *ih;
 489                         /* Sec 8.5.1 (A) */
 490                         if (sh->vtag)
 491                                 return false;
 492
 493                         ih = skb_header_pointer(skb, offset + sizeof(_sch),
 494                                                 sizeof(_inithdr), &_inithdr);
 495                         if (!ih)
 496                                 return false;
 497
 498                         pr_debug("Setting vtag %x for new conn\n",
 499                                  ih->init_tag);
 500
 501                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = ih->init_tag;
 502                 } else if (sch->type == SCTP_CID_HEARTBEAT) {
 503                         pr_debug("Setting vtag %x for secondary conntrack\n",
 504                                  sh->vtag);
 505                         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] = sh->vtag;
 506                 }
 507                 /* If it is a shutdown ack OOTB packet, we expect a return
 508                    shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
 509                 else {
 510                         pr_debug("Setting vtag %x for new conn OOTB\n",
 511                                  sh->vtag);
 512                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
 513                 }
 514
 515                 ct->proto.sctp.state = new_state;
 516         }
 517
 518         return true;
 519 }
 520
 521 static int sctp_error(struct net *net, struct nf_conn *tpl, struct sk_buff *skb,
 522                       unsigned int dataoff,
 523                       u8 pf, unsigned int hooknum)
 524 {
 525         const struct sctphdr *sh;
 526         const char *logmsg;
 527
 528         if (skb->len < dataoff + sizeof(struct sctphdr)) {
 529                 logmsg = "nf_ct_sctp: short packet ";
 530                 goto out_invalid;
 531         }
 532         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 533             skb->ip_summed == CHECKSUM_NONE) {
 534                 if (!skb_make_writable(skb, dataoff + sizeof(struct sctphdr))) {
 535                         logmsg = "nf_ct_sctp: failed to read header ";
 536                         goto out_invalid;
 537                 }
 538                 sh = (const struct sctphdr *)(skb->data + dataoff);
 539                 if (sh->checksum != sctp_compute_cksum(skb, dataoff)) {
 540                         logmsg = "nf_ct_sctp: bad CRC ";
 541                         goto out_invalid;
 542                 }
 543                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 544         }
 545         return NF_ACCEPT;
 546 out_invalid:
 547         nf_l4proto_log_invalid(skb, net, pf, IPPROTO_SCTP, "%s", logmsg);
 548         return -NF_ACCEPT;
 549 }
 550
 551 static bool sctp_can_early_drop(const struct nf_conn *ct)
 552 {
 553         switch (ct->proto.sctp.state) {
 554         case SCTP_CONNTRACK_SHUTDOWN_SENT:
 555         case SCTP_CONNTRACK_SHUTDOWN_RECD:
 556         case SCTP_CONNTRACK_SHUTDOWN_ACK_SENT:
 557                 return true;
 558         default:
 559                 break;
 560         }
 561
 562         return false;
 563 }
 564
 565 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 566
 567 #include <linux/netfilter/nfnetlink.h>
 568 #include <linux/netfilter/nfnetlink_conntrack.h>
 569
 570 static int sctp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 571                           struct nf_conn *ct)
 572 {
 573         struct nlattr *nest_parms;
 574
 575         spin_lock_bh(&ct->lock);
 576         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_SCTP | NLA_F_NESTED);
 577         if (!nest_parms)
 578                 goto nla_put_failure;
 579
 580         if (nla_put_u8(skb, CTA_PROTOINFO_SCTP_STATE, ct->proto.sctp.state) ||
 581             nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_ORIGINAL,
 582                          ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL]) ||
 583             nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_REPLY,
 584                          ct->proto.sctp.vtag[IP_CT_DIR_REPLY]))
 585                 goto nla_put_failure;
 586
 587         spin_unlock_bh(&ct->lock);
 588
 589         nla_nest_end(skb, nest_parms);
 590
 591         return 0;
 592
 593 nla_put_failure:
 594         spin_unlock_bh(&ct->lock);
 595         return -1;
 596 }
 597
 598 static const struct nla_policy sctp_nla_policy[CTA_PROTOINFO_SCTP_MAX+1] = {
 599         [CTA_PROTOINFO_SCTP_STATE]          = { .type = NLA_U8 },
 600         [CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]  = { .type = NLA_U32 },
 601         [CTA_PROTOINFO_SCTP_VTAG_REPLY]     = { .type = NLA_U32 },
 602 };
 603
 604 #define SCTP_NLATTR_SIZE ( \
 605                 NLA_ALIGN(NLA_HDRLEN + 1) + \
 606                 NLA_ALIGN(NLA_HDRLEN + 4) + \
 607                 NLA_ALIGN(NLA_HDRLEN + 4))
 608
 609 static int nlattr_to_sctp(struct nlattr *cda[], struct nf_conn *ct)
 610 {
 611         struct nlattr *attr = cda[CTA_PROTOINFO_SCTP];
 612         struct nlattr *tb[CTA_PROTOINFO_SCTP_MAX+1];
 613         int err;
 614
 615         /* updates may not contain the internal protocol info, skip parsing */
 616         if (!attr)
 617                 return 0;
 618
 619         err = nla_parse_nested(tb, CTA_PROTOINFO_SCTP_MAX, attr,
 620                                sctp_nla_policy, NULL);
 621         if (err < 0)
 622                 return err;
 623
 624         if (!tb[CTA_PROTOINFO_SCTP_STATE] ||
 625             !tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL] ||
 626             !tb[CTA_PROTOINFO_SCTP_VTAG_REPLY])
 627                 return -EINVAL;
 628
 629         spin_lock_bh(&ct->lock);
 630         ct->proto.sctp.state = nla_get_u8(tb[CTA_PROTOINFO_SCTP_STATE]);
 631         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] =
 632                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]);
 633         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
 634                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_REPLY]);
 635         spin_unlock_bh(&ct->lock);
 636
 637         return 0;
 638 }
 639 #endif
 640
 641 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 642
 643 #include <linux/netfilter/nfnetlink.h>
 644 #include <linux/netfilter/nfnetlink_cttimeout.h>
 645
 646 static int sctp_timeout_nlattr_to_obj(struct nlattr *tb[],
 647                                       struct net *net, void *data)
 648 {
 649         unsigned int *timeouts = data;
 650         struct nf_sctp_net *sn = sctp_pernet(net);
 651         int i;
 652
 653         if (!timeouts)
 654                 timeouts = sn->timeouts;
 655
 656         /* set default SCTP timeouts. */
 657         for (i=0; i<SCTP_CONNTRACK_MAX; i++)
 658                 timeouts[i] = sn->timeouts[i];
 659
 660         /* there's a 1:1 mapping between attributes and protocol states. */
 661         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 662                 if (tb[i]) {
 663                         timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
 664                 }
 665         }
 666
 667         timeouts[CTA_TIMEOUT_SCTP_UNSPEC] = timeouts[CTA_TIMEOUT_SCTP_CLOSED];
 668         return 0;
 669 }
 670
 671 static int
 672 sctp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 673 {
 674         const unsigned int *timeouts = data;
 675         int i;
 676
 677         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 678                 if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
 679                         goto nla_put_failure;
 680         }
 681         return 0;
 682
 683 nla_put_failure:
 684         return -ENOSPC;
 685 }
 686
 687 static const struct nla_policy
 688 sctp_timeout_nla_policy[CTA_TIMEOUT_SCTP_MAX+1] = {
 689         [CTA_TIMEOUT_SCTP_CLOSED]               = { .type = NLA_U32 },
 690         [CTA_TIMEOUT_SCTP_COOKIE_WAIT]          = { .type = NLA_U32 },
 691         [CTA_TIMEOUT_SCTP_COOKIE_ECHOED]        = { .type = NLA_U32 },
 692         [CTA_TIMEOUT_SCTP_ESTABLISHED]          = { .type = NLA_U32 },
 693         [CTA_TIMEOUT_SCTP_SHUTDOWN_SENT]        = { .type = NLA_U32 },
 694         [CTA_TIMEOUT_SCTP_SHUTDOWN_RECD]        = { .type = NLA_U32 },
 695         [CTA_TIMEOUT_SCTP_SHUTDOWN_ACK_SENT]    = { .type = NLA_U32 },
 696         [CTA_TIMEOUT_SCTP_HEARTBEAT_SENT]       = { .type = NLA_U32 },
 697         [CTA_TIMEOUT_SCTP_HEARTBEAT_ACKED]      = { .type = NLA_U32 },
 698 };
 699 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 700
 701
 702 #ifdef CONFIG_SYSCTL
 703 static struct ctl_table sctp_sysctl_table[] = {
 704         {
 705                 .procname       = "nf_conntrack_sctp_timeout_closed",
 706                 .maxlen         = sizeof(unsigned int),
 707                 .mode           = 0644,
 708                 .proc_handler   = proc_dointvec_jiffies,
 709         },
 710         {
 711                 .procname       = "nf_conntrack_sctp_timeout_cookie_wait",
 712                 .maxlen         = sizeof(unsigned int),
 713                 .mode           = 0644,
 714                 .proc_handler   = proc_dointvec_jiffies,
 715         },
 716         {
 717                 .procname       = "nf_conntrack_sctp_timeout_cookie_echoed",
 718                 .maxlen         = sizeof(unsigned int),
 719                 .mode           = 0644,
 720                 .proc_handler   = proc_dointvec_jiffies,
 721         },
 722         {
 723                 .procname       = "nf_conntrack_sctp_timeout_established",
 724                 .maxlen         = sizeof(unsigned int),
 725                 .mode           = 0644,
 726                 .proc_handler   = proc_dointvec_jiffies,
 727         },
 728         {
 729                 .procname       = "nf_conntrack_sctp_timeout_shutdown_sent",
 730                 .maxlen         = sizeof(unsigned int),
 731                 .mode           = 0644,
 732                 .proc_handler   = proc_dointvec_jiffies,
 733         },
 734         {
 735                 .procname       = "nf_conntrack_sctp_timeout_shutdown_recd",
 736                 .maxlen         = sizeof(unsigned int),
 737                 .mode           = 0644,
 738                 .proc_handler   = proc_dointvec_jiffies,
 739         },
 740         {
 741                 .procname       = "nf_conntrack_sctp_timeout_shutdown_ack_sent",
 742                 .maxlen         = sizeof(unsigned int),
 743                 .mode           = 0644,
 744                 .proc_handler   = proc_dointvec_jiffies,
 745         },
 746         {
 747                 .procname       = "nf_conntrack_sctp_timeout_heartbeat_sent",
 748                 .maxlen         = sizeof(unsigned int),
 749                 .mode           = 0644,
 750                 .proc_handler   = proc_dointvec_jiffies,
 751         },
 752         {
 753                 .procname       = "nf_conntrack_sctp_timeout_heartbeat_acked",
 754                 .maxlen         = sizeof(unsigned int),
 755                 .mode           = 0644,
 756                 .proc_handler   = proc_dointvec_jiffies,
 757         },
 758         { }
 759 };
 760 #endif
 761
 762 static int sctp_kmemdup_sysctl_table(struct nf_proto_net *pn,
 763                                      struct nf_sctp_net *sn)
 764 {
 765 #ifdef CONFIG_SYSCTL
 766         if (pn->ctl_table)
 767                 return 0;
 768
 769         pn->ctl_table = kmemdup(sctp_sysctl_table,
 770                                 sizeof(sctp_sysctl_table),
 771                                 GFP_KERNEL);
 772         if (!pn->ctl_table)
 773                 return -ENOMEM;
 774
 775         pn->ctl_table[0].data = &sn->timeouts[SCTP_CONNTRACK_CLOSED];
 776         pn->ctl_table[1].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_WAIT];
 777         pn->ctl_table[2].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_ECHOED];
 778         pn->ctl_table[3].data = &sn->timeouts[SCTP_CONNTRACK_ESTABLISHED];
 779         pn->ctl_table[4].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_SENT];
 780         pn->ctl_table[5].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_RECD];
 781         pn->ctl_table[6].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_ACK_SENT];
 782         pn->ctl_table[7].data = &sn->timeouts[SCTP_CONNTRACK_HEARTBEAT_SENT];
 783         pn->ctl_table[8].data = &sn->timeouts[SCTP_CONNTRACK_HEARTBEAT_ACKED];
 784 #endif
 785         return 0;
 786 }
 787
 788 static int sctp_init_net(struct net *net, u_int16_t proto)
 789 {
 790         struct nf_sctp_net *sn = sctp_pernet(net);
 791         struct nf_proto_net *pn = &sn->pn;
 792
 793         if (!pn->users) {
 794                 int i;
 795
 796                 for (i = 0; i < SCTP_CONNTRACK_MAX; i++)
 797                         sn->timeouts[i] = sctp_timeouts[i];
 798
 799                 /* timeouts[0] is unused, init it so ->timeouts[0] contains
 800                  * 'new' timeout, like udp or icmp.
 801                  */
 802                 sn->timeouts[0] = sctp_timeouts[SCTP_CONNTRACK_CLOSED];
 803         }
 804
 805         return sctp_kmemdup_sysctl_table(pn, sn);
 806 }
 807
 808 static struct nf_proto_net *sctp_get_net_proto(struct net *net)
 809 {
 810         return &net->ct.nf_ct_proto.sctp.pn;
 811 }
 812
 813 const struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp4 = {
 814         .l3proto                = PF_INET,
 815         .l4proto                = IPPROTO_SCTP,
 816 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 817         .print_conntrack        = sctp_print_conntrack,
 818 #endif
 819         .packet                 = sctp_packet,
 820         .new                    = sctp_new,
 821         .error                  = sctp_error,
 822         .can_early_drop         = sctp_can_early_drop,
 823         .me                     = THIS_MODULE,
 824 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 825         .nlattr_size            = SCTP_NLATTR_SIZE,
 826         .to_nlattr              = sctp_to_nlattr,
 827         .from_nlattr            = nlattr_to_sctp,
 828         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 829         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 830         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 831         .nla_policy             = nf_ct_port_nla_policy,
 832 #endif
 833 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 834         .ctnl_timeout           = {
 835                 .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
 836                 .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
 837                 .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
 838                 .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
 839                 .nla_policy     = sctp_timeout_nla_policy,
 840         },
 841 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 842         .init_net               = sctp_init_net,
 843         .get_net_proto          = sctp_get_net_proto,
 844 };
 845 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_sctp4);
 846
 847 const struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp6 = {
 848         .l3proto                = PF_INET6,
 849         .l4proto                = IPPROTO_SCTP,
 850 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 851         .print_conntrack        = sctp_print_conntrack,
 852 #endif
 853         .packet                 = sctp_packet,
 854         .new                    = sctp_new,
 855         .error                  = sctp_error,
 856         .can_early_drop         = sctp_can_early_drop,
 857         .me                     = THIS_MODULE,
 858 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 859         .nlattr_size            = SCTP_NLATTR_SIZE,
 860         .to_nlattr              = sctp_to_nlattr,
 861         .from_nlattr            = nlattr_to_sctp,
 862         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 863         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 864         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 865         .nla_policy             = nf_ct_port_nla_policy,
 866 #endif
 867 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 868         .ctnl_timeout           = {
 869                 .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
 870                 .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
 871                 .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
 872                 .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
 873                 .nla_policy     = sctp_timeout_nla_policy,
 874         },
 875 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 876         .init_net               = sctp_init_net,
 877         .get_net_proto          = sctp_get_net_proto,
 878 };
 879 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_sctp6);