net/netfilter/nf_conntrack_proto_sctp.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Connection tracking protocol helper module for SCTP.
   4  *
   5  * Copyright (c) 2004 Kiran Kumar Immidi <immidi_kiran@yahoo.com>
   6  * Copyright (c) 2004-2012 Patrick McHardy <kaber@trash.net>
   7  *
   8  * SCTP is defined in RFC 2960. References to various sections in this code
   9  * are to this RFC.
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/timer.h>
  14 #include <linux/netfilter.h>
  15 #include <linux/in.h>
  16 #include <linux/ip.h>
  17 #include <linux/sctp.h>
  18 #include <linux/string.h>
  19 #include <linux/seq_file.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/interrupt.h>
  22 #include <net/sctp/checksum.h>
  23
  24 #include <net/netfilter/nf_log.h>
  25 #include <net/netfilter/nf_conntrack.h>
  26 #include <net/netfilter/nf_conntrack_l4proto.h>
  27 #include <net/netfilter/nf_conntrack_ecache.h>
  28 #include <net/netfilter/nf_conntrack_timeout.h>
  29
  30 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
  31    closely.  They're more complex. --RR
  32
  33    And so for me for SCTP :D -Kiran */
  34
  35 static const char *const sctp_conntrack_names[] = {
  36         "NONE",
  37         "CLOSED",
  38         "COOKIE_WAIT",
  39         "COOKIE_ECHOED",
  40         "ESTABLISHED",
  41         "SHUTDOWN_SENT",
  42         "SHUTDOWN_RECD",
  43         "SHUTDOWN_ACK_SENT",
  44         "HEARTBEAT_SENT",
  45         "HEARTBEAT_ACKED",
  46 };
  47
  48 #define SECS  * HZ
  49 #define MINS  * 60 SECS
  50 #define HOURS * 60 MINS
  51 #define DAYS  * 24 HOURS
  52
  53 static const unsigned int sctp_timeouts[SCTP_CONNTRACK_MAX] = {
  54         [SCTP_CONNTRACK_CLOSED]                 = 10 SECS,
  55         [SCTP_CONNTRACK_COOKIE_WAIT]            = 3 SECS,
  56         [SCTP_CONNTRACK_COOKIE_ECHOED]          = 3 SECS,
  57         [SCTP_CONNTRACK_ESTABLISHED]            = 5 DAYS,
  58         [SCTP_CONNTRACK_SHUTDOWN_SENT]          = 300 SECS / 1000,
  59         [SCTP_CONNTRACK_SHUTDOWN_RECD]          = 300 SECS / 1000,
  60         [SCTP_CONNTRACK_SHUTDOWN_ACK_SENT]      = 3 SECS,
  61         [SCTP_CONNTRACK_HEARTBEAT_SENT]         = 30 SECS,
  62         [SCTP_CONNTRACK_HEARTBEAT_ACKED]        = 210 SECS,
  63         [SCTP_CONNTRACK_DATA_SENT]              = 30 SECS,
  64 };
  65
  66 #define SCTP_FLAG_HEARTBEAT_VTAG_FAILED 1
  67
  68 #define sNO SCTP_CONNTRACK_NONE
  69 #define sCL SCTP_CONNTRACK_CLOSED
  70 #define sCW SCTP_CONNTRACK_COOKIE_WAIT
  71 #define sCE SCTP_CONNTRACK_COOKIE_ECHOED
  72 #define sES SCTP_CONNTRACK_ESTABLISHED
  73 #define sSS SCTP_CONNTRACK_SHUTDOWN_SENT
  74 #define sSR SCTP_CONNTRACK_SHUTDOWN_RECD
  75 #define sSA SCTP_CONNTRACK_SHUTDOWN_ACK_SENT
  76 #define sHS SCTP_CONNTRACK_HEARTBEAT_SENT
  77 #define sHA SCTP_CONNTRACK_HEARTBEAT_ACKED
  78 #define sDS SCTP_CONNTRACK_DATA_SENT
  79 #define sIV SCTP_CONNTRACK_MAX
  80
  81 /*
  82         These are the descriptions of the states:
  83
  84 NOTE: These state names are tantalizingly similar to the states of an
  85 SCTP endpoint. But the interpretation of the states is a little different,
  86 considering that these are the states of the connection and not of an end
  87 point. Please note the subtleties. -Kiran
  88
  89 NONE              - Nothing so far.
  90 COOKIE WAIT       - We have seen an INIT chunk in the original direction, or also
  91                     an INIT_ACK chunk in the reply direction.
  92 COOKIE ECHOED     - We have seen a COOKIE_ECHO chunk in the original direction.
  93 ESTABLISHED       - We have seen a COOKIE_ACK in the reply direction.
  94 SHUTDOWN_SENT     - We have seen a SHUTDOWN chunk in the original direction.
  95 SHUTDOWN_RECD     - We have seen a SHUTDOWN chunk in the reply direction.
  96 SHUTDOWN_ACK_SENT - We have seen a SHUTDOWN_ACK chunk in the direction opposite
  97                     to that of the SHUTDOWN chunk.
  98 CLOSED            - We have seen a SHUTDOWN_COMPLETE chunk in the direction of
  99                     the SHUTDOWN chunk. Connection is closed.
 100 HEARTBEAT_SENT    - We have seen a HEARTBEAT in a new flow.
 101 HEARTBEAT_ACKED   - We have seen a HEARTBEAT-ACK/DATA/SACK in the direction
 102                     opposite to that of the HEARTBEAT/DATA chunk. Secondary connection
 103                     is established.
 104 DATA_SENT         - We have seen a DATA/SACK in a new flow.
 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][12][SCTP_CONNTRACK_MAX] = {
 119         {
 120 /*      ORIGINAL        */
 121 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA, sDS */
 122 /* init         */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCW, sHA, sCW},
 123 /* init_ack     */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA, sCL},
 124 /* abort        */ {sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
 125 /* shutdown     */ {sCL, sCL, sCW, sCE, sSS, sSS, sSR, sSA, sCL, sSS, sCL},
 126 /* shutdown_ack */ {sSA, sCL, sCW, sCE, sES, sSA, sSA, sSA, sSA, sHA, sSA},
 127 /* error        */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA, sCL},/* Can't have Stale cookie*/
 128 /* cookie_echo  */ {sCL, sCL, sCE, sCE, sES, sSS, sSR, sSA, sCL, sHA, sCL},/* 5.2.4 - Big TODO */
 129 /* cookie_ack   */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA, sCL},/* Can't come in orig dir */
 130 /* shutdown_comp*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sCL, sCL, sHA, sCL},
 131 /* heartbeat    */ {sHS, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA, sDS},
 132 /* heartbeat_ack*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA, sDS},
 133 /* data/sack    */ {sDS, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA, sDS}
 134         },
 135         {
 136 /*      REPLY   */
 137 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA, sDS */
 138 /* init         */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA, sIV},/* INIT in sCL Big TODO */
 139 /* init_ack     */ {sIV, sCW, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA, sIV},
 140 /* abort        */ {sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV, sCL, sIV},
 141 /* shutdown     */ {sIV, sCL, sCW, sCE, sSR, sSS, sSR, sSA, sIV, sSR, sIV},
 142 /* shutdown_ack */ {sIV, sCL, sCW, sCE, sES, sSA, sSA, sSA, sIV, sHA, sIV},
 143 /* error        */ {sIV, sCL, sCW, sCL, sES, sSS, sSR, sSA, sIV, sHA, sIV},
 144 /* cookie_echo  */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA, sIV},/* Can't come in reply dir */
 145 /* cookie_ack   */ {sIV, sCL, sCW, sES, sES, sSS, sSR, sSA, sIV, sHA, sIV},
 146 /* shutdown_comp*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sCL, sIV, sHA, sIV},
 147 /* heartbeat    */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA, sHA},
 148 /* heartbeat_ack*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHA, sHA, sHA},
 149 /* data/sack    */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHA, sHA, sHA},
 150         }
 151 };
 152
 153 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 154 /* Print out the private part of the conntrack. */
 155 static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 156 {
 157         seq_printf(s, "%s ", sctp_conntrack_names[ct->proto.sctp.state]);
 158 }
 159 #endif
 160
 161 #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count)     \
 162 for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0;        \
 163         (offset) < (skb)->len &&                                        \
 164         ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch)));   \
 165         (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
 166
 167 /* Some validity checks to make sure the chunks are fine */
 168 static int do_basic_checks(struct nf_conn *ct,
 169                            const struct sk_buff *skb,
 170                            unsigned int dataoff,
 171                            unsigned long *map)
 172 {
 173         u_int32_t offset, count;
 174         struct sctp_chunkhdr _sch, *sch;
 175         int flag;
 176
 177         flag = 0;
 178
 179         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 180                 pr_debug("Chunk Num: %d  Type: %d\n", count, sch->type);
 181
 182                 if (sch->type == SCTP_CID_INIT ||
 183                     sch->type == SCTP_CID_INIT_ACK ||
 184                     sch->type == SCTP_CID_SHUTDOWN_COMPLETE)
 185                         flag = 1;
 186
 187                 /*
 188                  * Cookie Ack/Echo chunks not the first OR
 189                  * Init / Init Ack / Shutdown compl chunks not the only chunks
 190                  * OR zero-length.
 191                  */
 192                 if (((sch->type == SCTP_CID_COOKIE_ACK ||
 193                       sch->type == SCTP_CID_COOKIE_ECHO ||
 194                       flag) &&
 195                      count != 0) || !sch->length) {
 196                         pr_debug("Basic checks failed\n");
 197                         return 1;
 198                 }
 199
 200                 if (map)
 201                         set_bit(sch->type, map);
 202         }
 203
 204         pr_debug("Basic checks passed\n");
 205         return count == 0;
 206 }
 207
 208 static int sctp_new_state(enum ip_conntrack_dir dir,
 209                           enum sctp_conntrack cur_state,
 210                           int chunk_type)
 211 {
 212         int i;
 213
 214         pr_debug("Chunk type: %d\n", chunk_type);
 215
 216         switch (chunk_type) {
 217         case SCTP_CID_INIT:
 218                 pr_debug("SCTP_CID_INIT\n");
 219                 i = 0;
 220                 break;
 221         case SCTP_CID_INIT_ACK:
 222                 pr_debug("SCTP_CID_INIT_ACK\n");
 223                 i = 1;
 224                 break;
 225         case SCTP_CID_ABORT:
 226                 pr_debug("SCTP_CID_ABORT\n");
 227                 i = 2;
 228                 break;
 229         case SCTP_CID_SHUTDOWN:
 230                 pr_debug("SCTP_CID_SHUTDOWN\n");
 231                 i = 3;
 232                 break;
 233         case SCTP_CID_SHUTDOWN_ACK:
 234                 pr_debug("SCTP_CID_SHUTDOWN_ACK\n");
 235                 i = 4;
 236                 break;
 237         case SCTP_CID_ERROR:
 238                 pr_debug("SCTP_CID_ERROR\n");
 239                 i = 5;
 240                 break;
 241         case SCTP_CID_COOKIE_ECHO:
 242                 pr_debug("SCTP_CID_COOKIE_ECHO\n");
 243                 i = 6;
 244                 break;
 245         case SCTP_CID_COOKIE_ACK:
 246                 pr_debug("SCTP_CID_COOKIE_ACK\n");
 247                 i = 7;
 248                 break;
 249         case SCTP_CID_SHUTDOWN_COMPLETE:
 250                 pr_debug("SCTP_CID_SHUTDOWN_COMPLETE\n");
 251                 i = 8;
 252                 break;
 253         case SCTP_CID_HEARTBEAT:
 254                 pr_debug("SCTP_CID_HEARTBEAT");
 255                 i = 9;
 256                 break;
 257         case SCTP_CID_HEARTBEAT_ACK:
 258                 pr_debug("SCTP_CID_HEARTBEAT_ACK");
 259                 i = 10;
 260                 break;
 261         case SCTP_CID_DATA:
 262         case SCTP_CID_SACK:
 263                 pr_debug("SCTP_CID_DATA/SACK");
 264                 i = 11;
 265                 break;
 266         default:
 267                 /* Other chunks like DATA or SACK do not change the state */
 268                 pr_debug("Unknown chunk type, Will stay in %s\n",
 269                          sctp_conntrack_names[cur_state]);
 270                 return cur_state;
 271         }
 272
 273         pr_debug("dir: %d   cur_state: %s  chunk_type: %d  new_state: %s\n",
 274                  dir, sctp_conntrack_names[cur_state], chunk_type,
 275                  sctp_conntrack_names[sctp_conntracks[dir][i][cur_state]]);
 276
 277         return sctp_conntracks[dir][i][cur_state];
 278 }
 279
 280 /* Don't need lock here: this conntrack not in circulation yet */
 281 static noinline bool
 282 sctp_new(struct nf_conn *ct, const struct sk_buff *skb,
 283          const struct sctphdr *sh, unsigned int dataoff)
 284 {
 285         enum sctp_conntrack new_state;
 286         const struct sctp_chunkhdr *sch;
 287         struct sctp_chunkhdr _sch;
 288         u32 offset, count;
 289
 290         memset(&ct->proto.sctp, 0, sizeof(ct->proto.sctp));
 291         new_state = SCTP_CONNTRACK_MAX;
 292         for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count) {
 293                 new_state = sctp_new_state(IP_CT_DIR_ORIGINAL,
 294                                            SCTP_CONNTRACK_NONE, sch->type);
 295
 296                 /* Invalid: delete conntrack */
 297                 if (new_state == SCTP_CONNTRACK_NONE ||
 298                     new_state == SCTP_CONNTRACK_MAX) {
 299                         pr_debug("nf_conntrack_sctp: invalid new deleting.\n");
 300                         return false;
 301                 }
 302
 303                 /* Copy the vtag into the state info */
 304                 if (sch->type == SCTP_CID_INIT) {
 305                         struct sctp_inithdr _inithdr, *ih;
 306                         /* Sec 8.5.1 (A) */
 307                         if (sh->vtag)
 308                                 return false;
 309
 310                         ih = skb_header_pointer(skb, offset + sizeof(_sch),
 311                                                 sizeof(_inithdr), &_inithdr);
 312                         if (!ih)
 313                                 return false;
 314
 315                         pr_debug("Setting vtag %x for new conn\n",
 316                                  ih->init_tag);
 317
 318                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = ih->init_tag;
 319                 } else if (sch->type == SCTP_CID_HEARTBEAT ||
 320                            sch->type == SCTP_CID_DATA ||
 321                            sch->type == SCTP_CID_SACK) {
 322                         pr_debug("Setting vtag %x for secondary conntrack\n",
 323                                  sh->vtag);
 324                         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] = sh->vtag;
 325                 } else {
 326                 /* If it is a shutdown ack OOTB packet, we expect a return
 327                    shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
 328                         pr_debug("Setting vtag %x for new conn OOTB\n",
 329                                  sh->vtag);
 330                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
 331                 }
 332
 333                 ct->proto.sctp.state = SCTP_CONNTRACK_NONE;
 334         }
 335
 336         return true;
 337 }
 338
 339 static bool sctp_error(struct sk_buff *skb,
 340                        unsigned int dataoff,
 341                        const struct nf_hook_state *state)
 342 {
 343         const struct sctphdr *sh;
 344         const char *logmsg;
 345
 346         if (skb->len < dataoff + sizeof(struct sctphdr)) {
 347                 logmsg = "nf_ct_sctp: short packet ";
 348                 goto out_invalid;
 349         }
 350         if (state->hook == NF_INET_PRE_ROUTING &&
 351             state->net->ct.sysctl_checksum &&
 352             skb->ip_summed == CHECKSUM_NONE) {
 353                 if (skb_ensure_writable(skb, dataoff + sizeof(*sh))) {
 354                         logmsg = "nf_ct_sctp: failed to read header ";
 355                         goto out_invalid;
 356                 }
 357                 sh = (const struct sctphdr *)(skb->data + dataoff);
 358                 if (sh->checksum != sctp_compute_cksum(skb, dataoff)) {
 359                         logmsg = "nf_ct_sctp: bad CRC ";
 360                         goto out_invalid;
 361                 }
 362                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 363         }
 364         return false;
 365 out_invalid:
 366         nf_l4proto_log_invalid(skb, state, IPPROTO_SCTP, "%s", logmsg);
 367         return true;
 368 }
 369
 370 /* Returns verdict for packet, or -NF_ACCEPT for invalid. */
 371 int nf_conntrack_sctp_packet(struct nf_conn *ct,
 372                              struct sk_buff *skb,
 373                              unsigned int dataoff,
 374                              enum ip_conntrack_info ctinfo,
 375                              const struct nf_hook_state *state)
 376 {
 377         enum sctp_conntrack new_state, old_state;
 378         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 379         const struct sctphdr *sh;
 380         struct sctphdr _sctph;
 381         const struct sctp_chunkhdr *sch;
 382         struct sctp_chunkhdr _sch;
 383         u_int32_t offset, count;
 384         unsigned int *timeouts;
 385         unsigned long map[256 / sizeof(unsigned long)] = { 0 };
 386         bool ignore = false;
 387
 388         if (sctp_error(skb, dataoff, state))
 389                 return -NF_ACCEPT;
 390
 391         sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
 392         if (sh == NULL)
 393                 goto out;
 394
 395         if (do_basic_checks(ct, skb, dataoff, map) != 0)
 396                 goto out;
 397
 398         if (!nf_ct_is_confirmed(ct)) {
 399                 /* If an OOTB packet has any of these chunks discard (Sec 8.4) */
 400                 if (test_bit(SCTP_CID_ABORT, map) ||
 401                     test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) ||
 402                     test_bit(SCTP_CID_COOKIE_ACK, map))
 403                         return -NF_ACCEPT;
 404
 405                 if (!sctp_new(ct, skb, sh, dataoff))
 406                         return -NF_ACCEPT;
 407         } else {
 408                 /* Check the verification tag (Sec 8.5) */
 409                 if (!test_bit(SCTP_CID_INIT, map) &&
 410                     !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) &&
 411                     !test_bit(SCTP_CID_COOKIE_ECHO, map) &&
 412                     !test_bit(SCTP_CID_ABORT, map) &&
 413                     !test_bit(SCTP_CID_SHUTDOWN_ACK, map) &&
 414                     !test_bit(SCTP_CID_HEARTBEAT, map) &&
 415                     !test_bit(SCTP_CID_HEARTBEAT_ACK, map) &&
 416                     sh->vtag != ct->proto.sctp.vtag[dir]) {
 417                         pr_debug("Verification tag check failed\n");
 418                         goto out;
 419                 }
 420         }
 421
 422         old_state = new_state = SCTP_CONNTRACK_NONE;
 423         spin_lock_bh(&ct->lock);
 424         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 425                 /* Special cases of Verification tag check (Sec 8.5.1) */
 426                 if (sch->type == SCTP_CID_INIT) {
 427                         /* Sec 8.5.1 (A) */
 428                         if (sh->vtag != 0)
 429                                 goto out_unlock;
 430                 } else if (sch->type == SCTP_CID_ABORT) {
 431                         /* Sec 8.5.1 (B) */
 432                         if (sh->vtag != ct->proto.sctp.vtag[dir] &&
 433                             sh->vtag != ct->proto.sctp.vtag[!dir])
 434                                 goto out_unlock;
 435                 } else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
 436                         /* Sec 8.5.1 (C) */
 437                         if (sh->vtag != ct->proto.sctp.vtag[dir] &&
 438                             sh->vtag != ct->proto.sctp.vtag[!dir] &&
 439                             sch->flags & SCTP_CHUNK_FLAG_T)
 440                                 goto out_unlock;
 441                 } else if (sch->type == SCTP_CID_COOKIE_ECHO) {
 442                         /* Sec 8.5.1 (D) */
 443                         if (sh->vtag != ct->proto.sctp.vtag[dir])
 444                                 goto out_unlock;
 445                 } else if (sch->type == SCTP_CID_HEARTBEAT) {
 446                         if (ct->proto.sctp.vtag[dir] == 0) {
 447                                 pr_debug("Setting %d vtag %x for dir %d\n", sch->type, sh->vtag, dir);
 448                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 449                         } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
 450                                 if (test_bit(SCTP_CID_DATA, map) || ignore)
 451                                         goto out_unlock;
 452
 453                                 ct->proto.sctp.flags |= SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 454                                 ct->proto.sctp.last_dir = dir;
 455                                 ignore = true;
 456                                 continue;
 457                         } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) {
 458                                 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 459                         }
 460                 } else if (sch->type == SCTP_CID_HEARTBEAT_ACK) {
 461                         if (ct->proto.sctp.vtag[dir] == 0) {
 462                                 pr_debug("Setting vtag %x for dir %d\n",
 463                                          sh->vtag, dir);
 464                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 465                         } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
 466                                 if (test_bit(SCTP_CID_DATA, map) || ignore)
 467                                         goto out_unlock;
 468
 469                                 if ((ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) == 0 ||
 470                                     ct->proto.sctp.last_dir == dir)
 471                                         goto out_unlock;
 472
 473                                 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 474                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 475                                 ct->proto.sctp.vtag[!dir] = 0;
 476                         } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) {
 477                                 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 478                         }
 479                 } else if (sch->type == SCTP_CID_DATA || sch->type == SCTP_CID_SACK) {
 480                         if (ct->proto.sctp.vtag[dir] == 0) {
 481                                 pr_debug("Setting vtag %x for dir %d\n", sh->vtag, dir);
 482                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 483                         }
 484                 }
 485
 486                 old_state = ct->proto.sctp.state;
 487                 new_state = sctp_new_state(dir, old_state, sch->type);
 488
 489                 /* Invalid */
 490                 if (new_state == SCTP_CONNTRACK_MAX) {
 491                         pr_debug("nf_conntrack_sctp: Invalid dir=%i ctype=%u "
 492                                  "conntrack=%u\n",
 493                                  dir, sch->type, old_state);
 494                         goto out_unlock;
 495                 }
 496
 497                 /* If it is an INIT or an INIT ACK note down the vtag */
 498                 if (sch->type == SCTP_CID_INIT ||
 499                     sch->type == SCTP_CID_INIT_ACK) {
 500                         struct sctp_inithdr _inithdr, *ih;
 501
 502                         ih = skb_header_pointer(skb, offset + sizeof(_sch),
 503                                                 sizeof(_inithdr), &_inithdr);
 504                         if (ih == NULL)
 505                                 goto out_unlock;
 506                         pr_debug("Setting vtag %x for dir %d\n",
 507                                  ih->init_tag, !dir);
 508                         ct->proto.sctp.vtag[!dir] = ih->init_tag;
 509
 510                         /* don't renew timeout on init retransmit so
 511                          * port reuse by client or NAT middlebox cannot
 512                          * keep entry alive indefinitely (incl. nat info).
 513                          */
 514                         if (new_state == SCTP_CONNTRACK_CLOSED &&
 515                             old_state == SCTP_CONNTRACK_CLOSED &&
 516                             nf_ct_is_confirmed(ct))
 517                                 ignore = true;
 518                 }
 519
 520                 ct->proto.sctp.state = new_state;
 521                 if (old_state != new_state)
 522                         nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
 523         }
 524         spin_unlock_bh(&ct->lock);
 525
 526         /* allow but do not refresh timeout */
 527         if (ignore)
 528                 return NF_ACCEPT;
 529
 530         timeouts = nf_ct_timeout_lookup(ct);
 531         if (!timeouts)
 532                 timeouts = nf_sctp_pernet(nf_ct_net(ct))->timeouts;
 533
 534         nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);
 535
 536         if (old_state == SCTP_CONNTRACK_COOKIE_ECHOED &&
 537             dir == IP_CT_DIR_REPLY &&
 538             new_state == SCTP_CONNTRACK_ESTABLISHED) {
 539                 pr_debug("Setting assured bit\n");
 540                 set_bit(IPS_ASSURED_BIT, &ct->status);
 541                 nf_conntrack_event_cache(IPCT_ASSURED, ct);
 542         }
 543
 544         return NF_ACCEPT;
 545
 546 out_unlock:
 547         spin_unlock_bh(&ct->lock);
 548 out:
 549         return -NF_ACCEPT;
 550 }
 551
 552 static bool sctp_can_early_drop(const struct nf_conn *ct)
 553 {
 554         switch (ct->proto.sctp.state) {
 555         case SCTP_CONNTRACK_SHUTDOWN_SENT:
 556         case SCTP_CONNTRACK_SHUTDOWN_RECD:
 557         case SCTP_CONNTRACK_SHUTDOWN_ACK_SENT:
 558                 return true;
 559         default:
 560                 break;
 561         }
 562
 563         return false;
 564 }
 565
 566 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 567
 568 #include <linux/netfilter/nfnetlink.h>
 569 #include <linux/netfilter/nfnetlink_conntrack.h>
 570
 571 static int sctp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 572                           struct nf_conn *ct, bool destroy)
 573 {
 574         struct nlattr *nest_parms;
 575
 576         spin_lock_bh(&ct->lock);
 577         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_SCTP);
 578         if (!nest_parms)
 579                 goto nla_put_failure;
 580
 581         if (nla_put_u8(skb, CTA_PROTOINFO_SCTP_STATE, ct->proto.sctp.state))
 582                 goto nla_put_failure;
 583
 584         if (destroy)
 585                 goto skip_state;
 586
 587         if (nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_ORIGINAL,
 588                          ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL]) ||
 589             nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_REPLY,
 590                          ct->proto.sctp.vtag[IP_CT_DIR_REPLY]))
 591                 goto nla_put_failure;
 592
 593 skip_state:
 594         spin_unlock_bh(&ct->lock);
 595         nla_nest_end(skb, nest_parms);
 596
 597         return 0;
 598
 599 nla_put_failure:
 600         spin_unlock_bh(&ct->lock);
 601         return -1;
 602 }
 603
 604 static const struct nla_policy sctp_nla_policy[CTA_PROTOINFO_SCTP_MAX+1] = {
 605         [CTA_PROTOINFO_SCTP_STATE]          = { .type = NLA_U8 },
 606         [CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]  = { .type = NLA_U32 },
 607         [CTA_PROTOINFO_SCTP_VTAG_REPLY]     = { .type = NLA_U32 },
 608 };
 609
 610 #define SCTP_NLATTR_SIZE ( \
 611                 NLA_ALIGN(NLA_HDRLEN + 1) + \
 612                 NLA_ALIGN(NLA_HDRLEN + 4) + \
 613                 NLA_ALIGN(NLA_HDRLEN + 4))
 614
 615 static int nlattr_to_sctp(struct nlattr *cda[], struct nf_conn *ct)
 616 {
 617         struct nlattr *attr = cda[CTA_PROTOINFO_SCTP];
 618         struct nlattr *tb[CTA_PROTOINFO_SCTP_MAX+1];
 619         int err;
 620
 621         /* updates may not contain the internal protocol info, skip parsing */
 622         if (!attr)
 623                 return 0;
 624
 625         err = nla_parse_nested_deprecated(tb, CTA_PROTOINFO_SCTP_MAX, attr,
 626                                           sctp_nla_policy, NULL);
 627         if (err < 0)
 628                 return err;
 629
 630         if (!tb[CTA_PROTOINFO_SCTP_STATE] ||
 631             !tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL] ||
 632             !tb[CTA_PROTOINFO_SCTP_VTAG_REPLY])
 633                 return -EINVAL;
 634
 635         spin_lock_bh(&ct->lock);
 636         ct->proto.sctp.state = nla_get_u8(tb[CTA_PROTOINFO_SCTP_STATE]);
 637         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] =
 638                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]);
 639         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
 640                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_REPLY]);
 641         spin_unlock_bh(&ct->lock);
 642
 643         return 0;
 644 }
 645 #endif
 646
 647 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 648
 649 #include <linux/netfilter/nfnetlink.h>
 650 #include <linux/netfilter/nfnetlink_cttimeout.h>
 651
 652 static int sctp_timeout_nlattr_to_obj(struct nlattr *tb[],
 653                                       struct net *net, void *data)
 654 {
 655         unsigned int *timeouts = data;
 656         struct nf_sctp_net *sn = nf_sctp_pernet(net);
 657         int i;
 658
 659         if (!timeouts)
 660                 timeouts = sn->timeouts;
 661
 662         /* set default SCTP timeouts. */
 663         for (i=0; i<SCTP_CONNTRACK_MAX; i++)
 664                 timeouts[i] = sn->timeouts[i];
 665
 666         /* there's a 1:1 mapping between attributes and protocol states. */
 667         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 668                 if (tb[i]) {
 669                         timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
 670                 }
 671         }
 672
 673         timeouts[CTA_TIMEOUT_SCTP_UNSPEC] = timeouts[CTA_TIMEOUT_SCTP_CLOSED];
 674         return 0;
 675 }
 676
 677 static int
 678 sctp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 679 {
 680         const unsigned int *timeouts = data;
 681         int i;
 682
 683         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 684                 if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
 685                         goto nla_put_failure;
 686         }
 687         return 0;
 688
 689 nla_put_failure:
 690         return -ENOSPC;
 691 }
 692
 693 static const struct nla_policy
 694 sctp_timeout_nla_policy[CTA_TIMEOUT_SCTP_MAX+1] = {
 695         [CTA_TIMEOUT_SCTP_CLOSED]               = { .type = NLA_U32 },
 696         [CTA_TIMEOUT_SCTP_COOKIE_WAIT]          = { .type = NLA_U32 },
 697         [CTA_TIMEOUT_SCTP_COOKIE_ECHOED]        = { .type = NLA_U32 },
 698         [CTA_TIMEOUT_SCTP_ESTABLISHED]          = { .type = NLA_U32 },
 699         [CTA_TIMEOUT_SCTP_SHUTDOWN_SENT]        = { .type = NLA_U32 },
 700         [CTA_TIMEOUT_SCTP_SHUTDOWN_RECD]        = { .type = NLA_U32 },
 701         [CTA_TIMEOUT_SCTP_SHUTDOWN_ACK_SENT]    = { .type = NLA_U32 },
 702         [CTA_TIMEOUT_SCTP_HEARTBEAT_SENT]       = { .type = NLA_U32 },
 703         [CTA_TIMEOUT_SCTP_HEARTBEAT_ACKED]      = { .type = NLA_U32 },
 704         [CTA_TIMEOUT_SCTP_DATA_SENT]            = { .type = NLA_U32 },
 705 };
 706 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 707
 708 void nf_conntrack_sctp_init_net(struct net *net)
 709 {
 710         struct nf_sctp_net *sn = nf_sctp_pernet(net);
 711         int i;
 712
 713         for (i = 0; i < SCTP_CONNTRACK_MAX; i++)
 714                 sn->timeouts[i] = sctp_timeouts[i];
 715
 716         /* timeouts[0] is unused, init it so ->timeouts[0] contains
 717          * 'new' timeout, like udp or icmp.
 718          */
 719         sn->timeouts[0] = sctp_timeouts[SCTP_CONNTRACK_CLOSED];
 720 }
 721
 722 const struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp = {
 723         .l4proto                = IPPROTO_SCTP,
 724 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 725         .print_conntrack        = sctp_print_conntrack,
 726 #endif
 727         .can_early_drop         = sctp_can_early_drop,
 728 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 729         .nlattr_size            = SCTP_NLATTR_SIZE,
 730         .to_nlattr              = sctp_to_nlattr,
 731         .from_nlattr            = nlattr_to_sctp,
 732         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 733         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 734         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 735         .nla_policy             = nf_ct_port_nla_policy,
 736 #endif
 737 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 738         .ctnl_timeout           = {
 739                 .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
 740                 .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
 741                 .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
 742                 .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
 743                 .nla_policy     = sctp_timeout_nla_policy,
 744         },
 745 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 746 };