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 static const char *const sctp_conntrack_names[] = {
  31         [SCTP_CONNTRACK_NONE]                   = "NONE",
  32         [SCTP_CONNTRACK_CLOSED]                 = "CLOSED",
  33         [SCTP_CONNTRACK_COOKIE_WAIT]            = "COOKIE_WAIT",
  34         [SCTP_CONNTRACK_COOKIE_ECHOED]          = "COOKIE_ECHOED",
  35         [SCTP_CONNTRACK_ESTABLISHED]            = "ESTABLISHED",
  36         [SCTP_CONNTRACK_SHUTDOWN_SENT]          = "SHUTDOWN_SENT",
  37         [SCTP_CONNTRACK_SHUTDOWN_RECD]          = "SHUTDOWN_RECD",
  38         [SCTP_CONNTRACK_SHUTDOWN_ACK_SENT]      = "SHUTDOWN_ACK_SENT",
  39         [SCTP_CONNTRACK_HEARTBEAT_SENT]         = "HEARTBEAT_SENT",
  40 };
  41
  42 #define SECS  * HZ
  43 #define MINS  * 60 SECS
  44 #define HOURS * 60 MINS
  45 #define DAYS  * 24 HOURS
  46
  47 static const unsigned int sctp_timeouts[SCTP_CONNTRACK_MAX] = {
  48         [SCTP_CONNTRACK_CLOSED]                 = 10 SECS,
  49         [SCTP_CONNTRACK_COOKIE_WAIT]            = 3 SECS,
  50         [SCTP_CONNTRACK_COOKIE_ECHOED]          = 3 SECS,
  51         [SCTP_CONNTRACK_ESTABLISHED]            = 210 SECS,
  52         [SCTP_CONNTRACK_SHUTDOWN_SENT]          = 3 SECS,
  53         [SCTP_CONNTRACK_SHUTDOWN_RECD]          = 3 SECS,
  54         [SCTP_CONNTRACK_SHUTDOWN_ACK_SENT]      = 3 SECS,
  55         [SCTP_CONNTRACK_HEARTBEAT_SENT]         = 30 SECS,
  56 };
  57
  58 #define SCTP_FLAG_HEARTBEAT_VTAG_FAILED 1
  59
  60 #define sNO SCTP_CONNTRACK_NONE
  61 #define sCL SCTP_CONNTRACK_CLOSED
  62 #define sCW SCTP_CONNTRACK_COOKIE_WAIT
  63 #define sCE SCTP_CONNTRACK_COOKIE_ECHOED
  64 #define sES SCTP_CONNTRACK_ESTABLISHED
  65 #define sSS SCTP_CONNTRACK_SHUTDOWN_SENT
  66 #define sSR SCTP_CONNTRACK_SHUTDOWN_RECD
  67 #define sSA SCTP_CONNTRACK_SHUTDOWN_ACK_SENT
  68 #define sHS SCTP_CONNTRACK_HEARTBEAT_SENT
  69 #define sIV SCTP_CONNTRACK_MAX
  70
  71 /*
  72         These are the descriptions of the states:
  73
  74 NOTE: These state names are tantalizingly similar to the states of an
  75 SCTP endpoint. But the interpretation of the states is a little different,
  76 considering that these are the states of the connection and not of an end
  77 point. Please note the subtleties. -Kiran
  78
  79 NONE              - Nothing so far.
  80 COOKIE WAIT       - We have seen an INIT chunk in the original direction, or also
  81                     an INIT_ACK chunk in the reply direction.
  82 COOKIE ECHOED     - We have seen a COOKIE_ECHO chunk in the original direction.
  83 ESTABLISHED       - We have seen a COOKIE_ACK in the reply direction.
  84 SHUTDOWN_SENT     - We have seen a SHUTDOWN chunk in the original direction.
  85 SHUTDOWN_RECD     - We have seen a SHUTDOWN chunk in the reply directoin.
  86 SHUTDOWN_ACK_SENT - We have seen a SHUTDOWN_ACK chunk in the direction opposite
  87                     to that of the SHUTDOWN chunk.
  88 CLOSED            - We have seen a SHUTDOWN_COMPLETE chunk in the direction of
  89                     the SHUTDOWN chunk. Connection is closed.
  90 HEARTBEAT_SENT    - We have seen a HEARTBEAT in a new flow.
  91 */
  92
  93 /* TODO
  94  - I have assumed that the first INIT is in the original direction.
  95  This messes things when an INIT comes in the reply direction in CLOSED
  96  state.
  97  - Check the error type in the reply dir before transitioning from
  98 cookie echoed to closed.
  99  - Sec 5.2.4 of RFC 2960
 100  - Full Multi Homing support.
 101 */
 102
 103 /* SCTP conntrack state transitions */
 104 static const u8 sctp_conntracks[2][11][SCTP_CONNTRACK_MAX] = {
 105         {
 106 /*      ORIGINAL        */
 107 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS */
 108 /* init         */ {sCL, sCL, sCW, sCE, sES, sCL, sCL, sSA, sCW},
 109 /* init_ack     */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL},
 110 /* abort        */ {sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
 111 /* shutdown     */ {sCL, sCL, sCW, sCE, sSS, sSS, sSR, sSA, sCL},
 112 /* shutdown_ack */ {sSA, sCL, sCW, sCE, sES, sSA, sSA, sSA, sSA},
 113 /* error        */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL},/* Can't have Stale cookie*/
 114 /* cookie_echo  */ {sCL, sCL, sCE, sCE, sES, sSS, sSR, sSA, sCL},/* 5.2.4 - Big TODO */
 115 /* cookie_ack   */ {sCL, sCL, sCW, sES, sES, sSS, sSR, sSA, sCL},/* Can't come in orig dir */
 116 /* shutdown_comp*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sCL, sCL},
 117 /* heartbeat    */ {sHS, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS},
 118 /* heartbeat_ack*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS},
 119         },
 120         {
 121 /*      REPLY   */
 122 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS */
 123 /* init         */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV},/* INIT in sCL Big TODO */
 124 /* init_ack     */ {sIV, sCW, sCW, sCE, sES, sSS, sSR, sSA, sIV},
 125 /* abort        */ {sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV},
 126 /* shutdown     */ {sIV, sCL, sCW, sCE, sSR, sSS, sSR, sSA, sIV},
 127 /* shutdown_ack */ {sIV, sCL, sCW, sCE, sES, sSA, sSA, sSA, sIV},
 128 /* error        */ {sIV, sCL, sCW, sCL, sES, sSS, sSR, sSA, sIV},
 129 /* cookie_echo  */ {sIV, sCL, sCE, sCE, sES, sSS, sSR, sSA, sIV},/* Can't come in reply dir */
 130 /* cookie_ack   */ {sIV, sCL, sCW, sES, sES, sSS, sSR, sSA, sIV},
 131 /* shutdown_comp*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sCL, sIV},
 132 /* heartbeat    */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS},
 133 /* heartbeat_ack*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sES},
 134         }
 135 };
 136
 137 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 138 /* Print out the private part of the conntrack. */
 139 static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 140 {
 141         seq_printf(s, "%s ", sctp_conntrack_names[ct->proto.sctp.state]);
 142 }
 143 #endif
 144
 145 #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count)     \
 146 for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0;        \
 147         (offset) < (skb)->len &&                                        \
 148         ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch)));   \
 149         (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
 150
 151 /* Some validity checks to make sure the chunks are fine */
 152 static int do_basic_checks(struct nf_conn *ct,
 153                            const struct sk_buff *skb,
 154                            unsigned int dataoff,
 155                            unsigned long *map)
 156 {
 157         u_int32_t offset, count;
 158         struct sctp_chunkhdr _sch, *sch;
 159         int flag;
 160
 161         flag = 0;
 162
 163         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 164                 pr_debug("Chunk Num: %d  Type: %d\n", count, sch->type);
 165
 166                 if (sch->type == SCTP_CID_INIT ||
 167                     sch->type == SCTP_CID_INIT_ACK ||
 168                     sch->type == SCTP_CID_SHUTDOWN_COMPLETE)
 169                         flag = 1;
 170
 171                 /*
 172                  * Cookie Ack/Echo chunks not the first OR
 173                  * Init / Init Ack / Shutdown compl chunks not the only chunks
 174                  * OR zero-length.
 175                  */
 176                 if (((sch->type == SCTP_CID_COOKIE_ACK ||
 177                       sch->type == SCTP_CID_COOKIE_ECHO ||
 178                       flag) &&
 179                      count != 0) || !sch->length) {
 180                         pr_debug("Basic checks failed\n");
 181                         return 1;
 182                 }
 183
 184                 if (map)
 185                         set_bit(sch->type, map);
 186         }
 187
 188         pr_debug("Basic checks passed\n");
 189         return count == 0;
 190 }
 191
 192 static int sctp_new_state(enum ip_conntrack_dir dir,
 193                           enum sctp_conntrack cur_state,
 194                           int chunk_type)
 195 {
 196         int i;
 197
 198         pr_debug("Chunk type: %d\n", chunk_type);
 199
 200         switch (chunk_type) {
 201         case SCTP_CID_INIT:
 202                 pr_debug("SCTP_CID_INIT\n");
 203                 i = 0;
 204                 break;
 205         case SCTP_CID_INIT_ACK:
 206                 pr_debug("SCTP_CID_INIT_ACK\n");
 207                 i = 1;
 208                 break;
 209         case SCTP_CID_ABORT:
 210                 pr_debug("SCTP_CID_ABORT\n");
 211                 i = 2;
 212                 break;
 213         case SCTP_CID_SHUTDOWN:
 214                 pr_debug("SCTP_CID_SHUTDOWN\n");
 215                 i = 3;
 216                 break;
 217         case SCTP_CID_SHUTDOWN_ACK:
 218                 pr_debug("SCTP_CID_SHUTDOWN_ACK\n");
 219                 i = 4;
 220                 break;
 221         case SCTP_CID_ERROR:
 222                 pr_debug("SCTP_CID_ERROR\n");
 223                 i = 5;
 224                 break;
 225         case SCTP_CID_COOKIE_ECHO:
 226                 pr_debug("SCTP_CID_COOKIE_ECHO\n");
 227                 i = 6;
 228                 break;
 229         case SCTP_CID_COOKIE_ACK:
 230                 pr_debug("SCTP_CID_COOKIE_ACK\n");
 231                 i = 7;
 232                 break;
 233         case SCTP_CID_SHUTDOWN_COMPLETE:
 234                 pr_debug("SCTP_CID_SHUTDOWN_COMPLETE\n");
 235                 i = 8;
 236                 break;
 237         case SCTP_CID_HEARTBEAT:
 238                 pr_debug("SCTP_CID_HEARTBEAT");
 239                 i = 9;
 240                 break;
 241         case SCTP_CID_HEARTBEAT_ACK:
 242                 pr_debug("SCTP_CID_HEARTBEAT_ACK");
 243                 i = 10;
 244                 break;
 245         default:
 246                 /* Other chunks like DATA or SACK do not change the state */
 247                 pr_debug("Unknown chunk type, Will stay in %s\n",
 248                          sctp_conntrack_names[cur_state]);
 249                 return cur_state;
 250         }
 251
 252         pr_debug("dir: %d   cur_state: %s  chunk_type: %d  new_state: %s\n",
 253                  dir, sctp_conntrack_names[cur_state], chunk_type,
 254                  sctp_conntrack_names[sctp_conntracks[dir][i][cur_state]]);
 255
 256         return sctp_conntracks[dir][i][cur_state];
 257 }
 258
 259 /* Don't need lock here: this conntrack not in circulation yet */
 260 static noinline bool
 261 sctp_new(struct nf_conn *ct, const struct sk_buff *skb,
 262          const struct sctphdr *sh, unsigned int dataoff)
 263 {
 264         enum sctp_conntrack new_state;
 265         const struct sctp_chunkhdr *sch;
 266         struct sctp_chunkhdr _sch;
 267         u32 offset, count;
 268
 269         memset(&ct->proto.sctp, 0, sizeof(ct->proto.sctp));
 270         new_state = SCTP_CONNTRACK_MAX;
 271         for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count) {
 272                 new_state = sctp_new_state(IP_CT_DIR_ORIGINAL,
 273                                            SCTP_CONNTRACK_NONE, sch->type);
 274
 275                 /* Invalid: delete conntrack */
 276                 if (new_state == SCTP_CONNTRACK_NONE ||
 277                     new_state == SCTP_CONNTRACK_MAX) {
 278                         pr_debug("nf_conntrack_sctp: invalid new deleting.\n");
 279                         return false;
 280                 }
 281
 282                 /* Copy the vtag into the state info */
 283                 if (sch->type == SCTP_CID_INIT) {
 284                         struct sctp_inithdr _inithdr, *ih;
 285                         /* Sec 8.5.1 (A) */
 286                         if (sh->vtag)
 287                                 return false;
 288
 289                         ih = skb_header_pointer(skb, offset + sizeof(_sch),
 290                                                 sizeof(_inithdr), &_inithdr);
 291                         if (!ih)
 292                                 return false;
 293
 294                         pr_debug("Setting vtag %x for new conn\n",
 295                                  ih->init_tag);
 296
 297                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = ih->init_tag;
 298                 } else if (sch->type == SCTP_CID_HEARTBEAT) {
 299                         pr_debug("Setting vtag %x for secondary conntrack\n",
 300                                  sh->vtag);
 301                         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] = sh->vtag;
 302                 } else if (sch->type == SCTP_CID_SHUTDOWN_ACK) {
 303                 /* If it is a shutdown ack OOTB packet, we expect a return
 304                    shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
 305                         pr_debug("Setting vtag %x for new conn OOTB\n",
 306                                  sh->vtag);
 307                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
 308                 }
 309
 310                 ct->proto.sctp.state = SCTP_CONNTRACK_NONE;
 311         }
 312
 313         return true;
 314 }
 315
 316 static bool sctp_error(struct sk_buff *skb,
 317                        unsigned int dataoff,
 318                        const struct nf_hook_state *state)
 319 {
 320         const struct sctphdr *sh;
 321         const char *logmsg;
 322
 323         if (skb->len < dataoff + sizeof(struct sctphdr)) {
 324                 logmsg = "nf_ct_sctp: short packet ";
 325                 goto out_invalid;
 326         }
 327         if (state->hook == NF_INET_PRE_ROUTING &&
 328             state->net->ct.sysctl_checksum &&
 329             skb->ip_summed == CHECKSUM_NONE) {
 330                 if (skb_ensure_writable(skb, dataoff + sizeof(*sh))) {
 331                         logmsg = "nf_ct_sctp: failed to read header ";
 332                         goto out_invalid;
 333                 }
 334                 sh = (const struct sctphdr *)(skb->data + dataoff);
 335                 if (sh->checksum != sctp_compute_cksum(skb, dataoff)) {
 336                         logmsg = "nf_ct_sctp: bad CRC ";
 337                         goto out_invalid;
 338                 }
 339                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 340         }
 341         return false;
 342 out_invalid:
 343         nf_l4proto_log_invalid(skb, state, IPPROTO_SCTP, "%s", logmsg);
 344         return true;
 345 }
 346
 347 /* Returns verdict for packet, or -NF_ACCEPT for invalid. */
 348 int nf_conntrack_sctp_packet(struct nf_conn *ct,
 349                              struct sk_buff *skb,
 350                              unsigned int dataoff,
 351                              enum ip_conntrack_info ctinfo,
 352                              const struct nf_hook_state *state)
 353 {
 354         enum sctp_conntrack new_state, old_state;
 355         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 356         const struct sctphdr *sh;
 357         struct sctphdr _sctph;
 358         const struct sctp_chunkhdr *sch;
 359         struct sctp_chunkhdr _sch;
 360         u_int32_t offset, count;
 361         unsigned int *timeouts;
 362         unsigned long map[256 / sizeof(unsigned long)] = { 0 };
 363         bool ignore = false;
 364
 365         if (sctp_error(skb, dataoff, state))
 366                 return -NF_ACCEPT;
 367
 368         sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
 369         if (sh == NULL)
 370                 goto out;
 371
 372         if (do_basic_checks(ct, skb, dataoff, map) != 0)
 373                 goto out;
 374
 375         if (!nf_ct_is_confirmed(ct)) {
 376                 /* If an OOTB packet has any of these chunks discard (Sec 8.4) */
 377                 if (test_bit(SCTP_CID_ABORT, map) ||
 378                     test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) ||
 379                     test_bit(SCTP_CID_COOKIE_ACK, map))
 380                         return -NF_ACCEPT;
 381
 382                 if (!sctp_new(ct, skb, sh, dataoff))
 383                         return -NF_ACCEPT;
 384         }
 385
 386         /* Check the verification tag (Sec 8.5) */
 387         if (!test_bit(SCTP_CID_INIT, map) &&
 388             !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) &&
 389             !test_bit(SCTP_CID_COOKIE_ECHO, map) &&
 390             !test_bit(SCTP_CID_ABORT, map) &&
 391             !test_bit(SCTP_CID_SHUTDOWN_ACK, map) &&
 392             !test_bit(SCTP_CID_HEARTBEAT, map) &&
 393             !test_bit(SCTP_CID_HEARTBEAT_ACK, map) &&
 394             sh->vtag != ct->proto.sctp.vtag[dir]) {
 395                 pr_debug("Verification tag check failed\n");
 396                 goto out;
 397         }
 398
 399         old_state = new_state = SCTP_CONNTRACK_NONE;
 400         spin_lock_bh(&ct->lock);
 401         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 402                 /* Special cases of Verification tag check (Sec 8.5.1) */
 403                 if (sch->type == SCTP_CID_INIT) {
 404                         /* (A) vtag MUST be zero */
 405                         if (sh->vtag != 0)
 406                                 goto out_unlock;
 407                 } else if (sch->type == SCTP_CID_ABORT) {
 408                         /* (B) vtag MUST match own vtag if T flag is unset OR
 409                          * MUST match peer's vtag if T flag is set
 410                          */
 411                         if ((!(sch->flags & SCTP_CHUNK_FLAG_T) &&
 412                              sh->vtag != ct->proto.sctp.vtag[dir]) ||
 413                             ((sch->flags & SCTP_CHUNK_FLAG_T) &&
 414                              sh->vtag != ct->proto.sctp.vtag[!dir]))
 415                                 goto out_unlock;
 416                 } else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
 417                         /* (C) vtag MUST match own vtag if T flag is unset OR
 418                          * MUST match peer's vtag if T flag is set
 419                          */
 420                         if ((!(sch->flags & SCTP_CHUNK_FLAG_T) &&
 421                              sh->vtag != ct->proto.sctp.vtag[dir]) ||
 422                             ((sch->flags & SCTP_CHUNK_FLAG_T) &&
 423                              sh->vtag != ct->proto.sctp.vtag[!dir]))
 424                                 goto out_unlock;
 425                 } else if (sch->type == SCTP_CID_COOKIE_ECHO) {
 426                         /* (D) vtag must be same as init_vtag as found in INIT_ACK */
 427                         if (sh->vtag != ct->proto.sctp.vtag[dir])
 428                                 goto out_unlock;
 429                 } else if (sch->type == SCTP_CID_COOKIE_ACK) {
 430                         ct->proto.sctp.init[dir] = 0;
 431                         ct->proto.sctp.init[!dir] = 0;
 432                 } else if (sch->type == SCTP_CID_HEARTBEAT) {
 433                         if (ct->proto.sctp.vtag[dir] == 0) {
 434                                 pr_debug("Setting %d vtag %x for dir %d\n", sch->type, sh->vtag, dir);
 435                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 436                         } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
 437                                 if (test_bit(SCTP_CID_DATA, map) || ignore)
 438                                         goto out_unlock;
 439
 440                                 ct->proto.sctp.flags |= SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 441                                 ct->proto.sctp.last_dir = dir;
 442                                 ignore = true;
 443                                 continue;
 444                         } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) {
 445                                 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 446                         }
 447                 } else if (sch->type == SCTP_CID_HEARTBEAT_ACK) {
 448                         if (ct->proto.sctp.vtag[dir] == 0) {
 449                                 pr_debug("Setting vtag %x for dir %d\n",
 450                                          sh->vtag, dir);
 451                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 452                         } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
 453                                 if (test_bit(SCTP_CID_DATA, map) || ignore)
 454                                         goto out_unlock;
 455
 456                                 if ((ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) == 0 ||
 457                                     ct->proto.sctp.last_dir == dir)
 458                                         goto out_unlock;
 459
 460                                 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 461                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 462                                 ct->proto.sctp.vtag[!dir] = 0;
 463                         } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) {
 464                                 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
 465                         }
 466                 }
 467
 468                 old_state = ct->proto.sctp.state;
 469                 new_state = sctp_new_state(dir, old_state, sch->type);
 470
 471                 /* Invalid */
 472                 if (new_state == SCTP_CONNTRACK_MAX) {
 473                         pr_debug("nf_conntrack_sctp: Invalid dir=%i ctype=%u "
 474                                  "conntrack=%u\n",
 475                                  dir, sch->type, old_state);
 476                         goto out_unlock;
 477                 }
 478
 479                 /* If it is an INIT or an INIT ACK note down the vtag */
 480                 if (sch->type == SCTP_CID_INIT) {
 481                         struct sctp_inithdr _ih, *ih;
 482
 483                         ih = skb_header_pointer(skb, offset + sizeof(_sch), sizeof(*ih), &_ih);
 484                         if (!ih)
 485                                 goto out_unlock;
 486
 487                         if (ct->proto.sctp.init[dir] && ct->proto.sctp.init[!dir])
 488                                 ct->proto.sctp.init[!dir] = 0;
 489                         ct->proto.sctp.init[dir] = 1;
 490
 491                         pr_debug("Setting vtag %x for dir %d\n", ih->init_tag, !dir);
 492                         ct->proto.sctp.vtag[!dir] = ih->init_tag;
 493
 494                         /* don't renew timeout on init retransmit so
 495                          * port reuse by client or NAT middlebox cannot
 496                          * keep entry alive indefinitely (incl. nat info).
 497                          */
 498                         if (new_state == SCTP_CONNTRACK_CLOSED &&
 499                             old_state == SCTP_CONNTRACK_CLOSED &&
 500                             nf_ct_is_confirmed(ct))
 501                                 ignore = true;
 502                 } else if (sch->type == SCTP_CID_INIT_ACK) {
 503                         struct sctp_inithdr _ih, *ih;
 504                         __be32 vtag;
 505
 506                         ih = skb_header_pointer(skb, offset + sizeof(_sch), sizeof(*ih), &_ih);
 507                         if (!ih)
 508                                 goto out_unlock;
 509
 510                         vtag = ct->proto.sctp.vtag[!dir];
 511                         if (!ct->proto.sctp.init[!dir] && vtag && vtag != ih->init_tag)
 512                                 goto out_unlock;
 513                         /* collision */
 514                         if (ct->proto.sctp.init[dir] && ct->proto.sctp.init[!dir] &&
 515                             vtag != ih->init_tag)
 516                                 goto out_unlock;
 517
 518                         pr_debug("Setting vtag %x for dir %d\n", ih->init_tag, !dir);
 519                         ct->proto.sctp.vtag[!dir] = ih->init_tag;
 520                 }
 521
 522                 ct->proto.sctp.state = new_state;
 523                 if (old_state != new_state) {
 524                         nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
 525                         if (new_state == SCTP_CONNTRACK_ESTABLISHED &&
 526                             !test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
 527                                 nf_conntrack_event_cache(IPCT_ASSURED, ct);
 528                 }
 529         }
 530         spin_unlock_bh(&ct->lock);
 531
 532         /* allow but do not refresh timeout */
 533         if (ignore)
 534                 return NF_ACCEPT;
 535
 536         timeouts = nf_ct_timeout_lookup(ct);
 537         if (!timeouts)
 538                 timeouts = nf_sctp_pernet(nf_ct_net(ct))->timeouts;
 539
 540         nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);
 541
 542         return NF_ACCEPT;
 543
 544 out_unlock:
 545         spin_unlock_bh(&ct->lock);
 546 out:
 547         return -NF_ACCEPT;
 548 }
 549
 550 static bool sctp_can_early_drop(const struct nf_conn *ct)
 551 {
 552         switch (ct->proto.sctp.state) {
 553         case SCTP_CONNTRACK_SHUTDOWN_SENT:
 554         case SCTP_CONNTRACK_SHUTDOWN_RECD:
 555         case SCTP_CONNTRACK_SHUTDOWN_ACK_SENT:
 556                 return true;
 557         default:
 558                 break;
 559         }
 560
 561         return false;
 562 }
 563
 564 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 565
 566 #include <linux/netfilter/nfnetlink.h>
 567 #include <linux/netfilter/nfnetlink_conntrack.h>
 568
 569 static int sctp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 570                           struct nf_conn *ct, bool destroy)
 571 {
 572         struct nlattr *nest_parms;
 573
 574         spin_lock_bh(&ct->lock);
 575         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_SCTP);
 576         if (!nest_parms)
 577                 goto nla_put_failure;
 578
 579         if (nla_put_u8(skb, CTA_PROTOINFO_SCTP_STATE, ct->proto.sctp.state))
 580                 goto nla_put_failure;
 581
 582         if (destroy)
 583                 goto skip_state;
 584
 585         if (nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_ORIGINAL,
 586                          ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL]) ||
 587             nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_REPLY,
 588                          ct->proto.sctp.vtag[IP_CT_DIR_REPLY]))
 589                 goto nla_put_failure;
 590
 591 skip_state:
 592         spin_unlock_bh(&ct->lock);
 593         nla_nest_end(skb, nest_parms);
 594
 595         return 0;
 596
 597 nla_put_failure:
 598         spin_unlock_bh(&ct->lock);
 599         return -1;
 600 }
 601
 602 static const struct nla_policy sctp_nla_policy[CTA_PROTOINFO_SCTP_MAX+1] = {
 603         [CTA_PROTOINFO_SCTP_STATE]          = { .type = NLA_U8 },
 604         [CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]  = { .type = NLA_U32 },
 605         [CTA_PROTOINFO_SCTP_VTAG_REPLY]     = { .type = NLA_U32 },
 606 };
 607
 608 #define SCTP_NLATTR_SIZE ( \
 609                 NLA_ALIGN(NLA_HDRLEN + 1) + \
 610                 NLA_ALIGN(NLA_HDRLEN + 4) + \
 611                 NLA_ALIGN(NLA_HDRLEN + 4))
 612
 613 static int nlattr_to_sctp(struct nlattr *cda[], struct nf_conn *ct)
 614 {
 615         struct nlattr *attr = cda[CTA_PROTOINFO_SCTP];
 616         struct nlattr *tb[CTA_PROTOINFO_SCTP_MAX+1];
 617         int err;
 618
 619         /* updates may not contain the internal protocol info, skip parsing */
 620         if (!attr)
 621                 return 0;
 622
 623         err = nla_parse_nested_deprecated(tb, CTA_PROTOINFO_SCTP_MAX, attr,
 624                                           sctp_nla_policy, NULL);
 625         if (err < 0)
 626                 return err;
 627
 628         if (!tb[CTA_PROTOINFO_SCTP_STATE] ||
 629             !tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL] ||
 630             !tb[CTA_PROTOINFO_SCTP_VTAG_REPLY])
 631                 return -EINVAL;
 632
 633         spin_lock_bh(&ct->lock);
 634         ct->proto.sctp.state = nla_get_u8(tb[CTA_PROTOINFO_SCTP_STATE]);
 635         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] =
 636                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]);
 637         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
 638                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_REPLY]);
 639         spin_unlock_bh(&ct->lock);
 640
 641         return 0;
 642 }
 643 #endif
 644
 645 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 646
 647 #include <linux/netfilter/nfnetlink.h>
 648 #include <linux/netfilter/nfnetlink_cttimeout.h>
 649
 650 static int sctp_timeout_nlattr_to_obj(struct nlattr *tb[],
 651                                       struct net *net, void *data)
 652 {
 653         unsigned int *timeouts = data;
 654         struct nf_sctp_net *sn = nf_sctp_pernet(net);
 655         int i;
 656
 657         if (!timeouts)
 658                 timeouts = sn->timeouts;
 659
 660         /* set default SCTP timeouts. */
 661         for (i=0; i<SCTP_CONNTRACK_MAX; i++)
 662                 timeouts[i] = sn->timeouts[i];
 663
 664         /* there's a 1:1 mapping between attributes and protocol states. */
 665         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 666                 if (tb[i]) {
 667                         timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
 668                 }
 669         }
 670
 671         timeouts[CTA_TIMEOUT_SCTP_UNSPEC] = timeouts[CTA_TIMEOUT_SCTP_CLOSED];
 672         return 0;
 673 }
 674
 675 static int
 676 sctp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 677 {
 678         const unsigned int *timeouts = data;
 679         int i;
 680
 681         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 682                 if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
 683                         goto nla_put_failure;
 684         }
 685         return 0;
 686
 687 nla_put_failure:
 688         return -ENOSPC;
 689 }
 690
 691 static const struct nla_policy
 692 sctp_timeout_nla_policy[CTA_TIMEOUT_SCTP_MAX+1] = {
 693         [CTA_TIMEOUT_SCTP_CLOSED]               = { .type = NLA_U32 },
 694         [CTA_TIMEOUT_SCTP_COOKIE_WAIT]          = { .type = NLA_U32 },
 695         [CTA_TIMEOUT_SCTP_COOKIE_ECHOED]        = { .type = NLA_U32 },
 696         [CTA_TIMEOUT_SCTP_ESTABLISHED]          = { .type = NLA_U32 },
 697         [CTA_TIMEOUT_SCTP_SHUTDOWN_SENT]        = { .type = NLA_U32 },
 698         [CTA_TIMEOUT_SCTP_SHUTDOWN_RECD]        = { .type = NLA_U32 },
 699         [CTA_TIMEOUT_SCTP_SHUTDOWN_ACK_SENT]    = { .type = NLA_U32 },
 700         [CTA_TIMEOUT_SCTP_HEARTBEAT_SENT]       = { .type = NLA_U32 },
 701         [CTA_TIMEOUT_SCTP_HEARTBEAT_ACKED]      = { .type = NLA_U32 },
 702 };
 703 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 704
 705 void nf_conntrack_sctp_init_net(struct net *net)
 706 {
 707         struct nf_sctp_net *sn = nf_sctp_pernet(net);
 708         int i;
 709
 710         for (i = 0; i < SCTP_CONNTRACK_MAX; i++)
 711                 sn->timeouts[i] = sctp_timeouts[i];
 712
 713         /* timeouts[0] is unused, init it so ->timeouts[0] contains
 714          * 'new' timeout, like udp or icmp.
 715          */
 716         sn->timeouts[0] = sctp_timeouts[SCTP_CONNTRACK_CLOSED];
 717 }
 718
 719 const struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp = {
 720         .l4proto                = IPPROTO_SCTP,
 721 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 722         .print_conntrack        = sctp_print_conntrack,
 723 #endif
 724         .can_early_drop         = sctp_can_early_drop,
 725 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 726         .nlattr_size            = SCTP_NLATTR_SIZE,
 727         .to_nlattr              = sctp_to_nlattr,
 728         .from_nlattr            = nlattr_to_sctp,
 729         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 730         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 731         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 732         .nla_policy             = nf_ct_port_nla_policy,
 733 #endif
 734 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 735         .ctnl_timeout           = {
 736                 .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
 737                 .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
 738                 .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
 739                 .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
 740                 .nla_policy     = sctp_timeout_nla_policy,
 741         },
 742 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 743 };