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
  32 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
  33    closely.  They're more complex. --RR
  34
  35    And so for me for SCTP :D -Kiran */
  36
  37 static const char *const sctp_conntrack_names[] = {
  38         "NONE",
  39         "CLOSED",
  40         "COOKIE_WAIT",
  41         "COOKIE_ECHOED",
  42         "ESTABLISHED",
  43         "SHUTDOWN_SENT",
  44         "SHUTDOWN_RECD",
  45         "SHUTDOWN_ACK_SENT",
  46         "HEARTBEAT_SENT",
  47         "HEARTBEAT_ACKED",
  48 };
  49
  50 #define SECS  * HZ
  51 #define MINS  * 60 SECS
  52 #define HOURS * 60 MINS
  53 #define DAYS  * 24 HOURS
  54
  55 static unsigned int sctp_timeouts[SCTP_CONNTRACK_MAX] __read_mostly = {
  56         [SCTP_CONNTRACK_CLOSED]                 = 10 SECS,
  57         [SCTP_CONNTRACK_COOKIE_WAIT]            = 3 SECS,
  58         [SCTP_CONNTRACK_COOKIE_ECHOED]          = 3 SECS,
  59         [SCTP_CONNTRACK_ESTABLISHED]            = 5 DAYS,
  60         [SCTP_CONNTRACK_SHUTDOWN_SENT]          = 300 SECS / 1000,
  61         [SCTP_CONNTRACK_SHUTDOWN_RECD]          = 300 SECS / 1000,
  62         [SCTP_CONNTRACK_SHUTDOWN_ACK_SENT]      = 3 SECS,
  63         [SCTP_CONNTRACK_HEARTBEAT_SENT]         = 30 SECS,
  64         [SCTP_CONNTRACK_HEARTBEAT_ACKED]        = 210 SECS,
  65 };
  66
  67 #define sNO SCTP_CONNTRACK_NONE
  68 #define sCL SCTP_CONNTRACK_CLOSED
  69 #define sCW SCTP_CONNTRACK_COOKIE_WAIT
  70 #define sCE SCTP_CONNTRACK_COOKIE_ECHOED
  71 #define sES SCTP_CONNTRACK_ESTABLISHED
  72 #define sSS SCTP_CONNTRACK_SHUTDOWN_SENT
  73 #define sSR SCTP_CONNTRACK_SHUTDOWN_RECD
  74 #define sSA SCTP_CONNTRACK_SHUTDOWN_ACK_SENT
  75 #define sHS SCTP_CONNTRACK_HEARTBEAT_SENT
  76 #define sHA SCTP_CONNTRACK_HEARTBEAT_ACKED
  77 #define sIV SCTP_CONNTRACK_MAX
  78
  79 /*
  80         These are the descriptions of the states:
  81
  82 NOTE: These state names are tantalizingly similar to the states of an
  83 SCTP endpoint. But the interpretation of the states is a little different,
  84 considering that these are the states of the connection and not of an end
  85 point. Please note the subtleties. -Kiran
  86
  87 NONE              - Nothing so far.
  88 COOKIE WAIT       - We have seen an INIT chunk in the original direction, or also
  89                     an INIT_ACK chunk in the reply direction.
  90 COOKIE ECHOED     - We have seen a COOKIE_ECHO chunk in the original direction.
  91 ESTABLISHED       - We have seen a COOKIE_ACK in the reply direction.
  92 SHUTDOWN_SENT     - We have seen a SHUTDOWN chunk in the original direction.
  93 SHUTDOWN_RECD     - We have seen a SHUTDOWN chunk in the reply directoin.
  94 SHUTDOWN_ACK_SENT - We have seen a SHUTDOWN_ACK chunk in the direction opposite
  95                     to that of the SHUTDOWN chunk.
  96 CLOSED            - We have seen a SHUTDOWN_COMPLETE chunk in the direction of
  97                     the SHUTDOWN chunk. Connection is closed.
  98 HEARTBEAT_SENT    - We have seen a HEARTBEAT in a new flow.
  99 HEARTBEAT_ACKED   - We have seen a HEARTBEAT-ACK in the direction opposite to
 100                     that of the HEARTBEAT chunk. Secondary connection is
 101                     established.
 102 */
 103
 104 /* TODO
 105  - I have assumed that the first INIT is in the original direction.
 106  This messes things when an INIT comes in the reply direction in CLOSED
 107  state.
 108  - Check the error type in the reply dir before transitioning from
 109 cookie echoed to closed.
 110  - Sec 5.2.4 of RFC 2960
 111  - Full Multi Homing support.
 112 */
 113
 114 /* SCTP conntrack state transitions */
 115 static const u8 sctp_conntracks[2][11][SCTP_CONNTRACK_MAX] = {
 116         {
 117 /*      ORIGINAL        */
 118 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA */
 119 /* init         */ {sCW, sCW, sCW, sCE, sES, sSS, sSR, sSA, sCW, sHA},
 120 /* init_ack     */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA},
 121 /* abort        */ {sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
 122 /* shutdown     */ {sCL, sCL, sCW, sCE, sSS, sSS, sSR, sSA, sCL, sSS},
 123 /* shutdown_ack */ {sSA, sCL, sCW, sCE, sES, sSA, sSA, sSA, sSA, sHA},
 124 /* error        */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA},/* Can't have Stale cookie*/
 125 /* cookie_echo  */ {sCL, sCL, sCE, sCE, sES, sSS, sSR, sSA, sCL, sHA},/* 5.2.4 - Big TODO */
 126 /* cookie_ack   */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA},/* Can't come in orig dir */
 127 /* shutdown_comp*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sCL, sCL, sHA},
 128 /* heartbeat    */ {sHS, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA},
 129 /* heartbeat_ack*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA}
 130         },
 131         {
 132 /*      REPLY   */
 133 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA */
 134 /* init         */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},/* INIT in sCL Big TODO */
 135 /* init_ack     */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},
 136 /* abort        */ {sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV, sCL},
 137 /* shutdown     */ {sIV, sCL, sCW, sCE, sSR, sSS, sSR, sSA, sIV, sSR},
 138 /* shutdown_ack */ {sIV, sCL, sCW, sCE, sES, sSA, sSA, sSA, sIV, sHA},
 139 /* error        */ {sIV, sCL, sCW, sCL, sES, sSS, sSR, sSA, sIV, sHA},
 140 /* cookie_echo  */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},/* Can't come in reply dir */
 141 /* cookie_ack   */ {sIV, sCL, sCW, sES, sES, sSS, sSR, sSA, sIV, sHA},
 142 /* shutdown_comp*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sCL, sIV, sHA},
 143 /* heartbeat    */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA},
 144 /* heartbeat_ack*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHA, sHA}
 145         }
 146 };
 147
 148 static inline struct nf_sctp_net *sctp_pernet(struct net *net)
 149 {
 150         return &net->ct.nf_ct_proto.sctp;
 151 }
 152
 153 static bool sctp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
 154                               struct net *net, struct nf_conntrack_tuple *tuple)
 155 {
 156         const struct sctphdr *hp;
 157         struct sctphdr _hdr;
 158
 159         /* Actually only need first 4 bytes to get ports. */
 160         hp = skb_header_pointer(skb, dataoff, 4, &_hdr);
 161         if (hp == NULL)
 162                 return false;
 163
 164         tuple->src.u.sctp.port = hp->source;
 165         tuple->dst.u.sctp.port = hp->dest;
 166         return true;
 167 }
 168
 169 static bool sctp_invert_tuple(struct nf_conntrack_tuple *tuple,
 170                               const struct nf_conntrack_tuple *orig)
 171 {
 172         tuple->src.u.sctp.port = orig->dst.u.sctp.port;
 173         tuple->dst.u.sctp.port = orig->src.u.sctp.port;
 174         return true;
 175 }
 176
 177 /* Print out the per-protocol part of the tuple. */
 178 static void sctp_print_tuple(struct seq_file *s,
 179                              const struct nf_conntrack_tuple *tuple)
 180 {
 181         seq_printf(s, "sport=%hu dport=%hu ",
 182                    ntohs(tuple->src.u.sctp.port),
 183                    ntohs(tuple->dst.u.sctp.port));
 184 }
 185
 186 /* Print out the private part of the conntrack. */
 187 static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 188 {
 189         seq_printf(s, "%s ", sctp_conntrack_names[ct->proto.sctp.state]);
 190 }
 191
 192 #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count)     \
 193 for ((offset) = (dataoff) + sizeof(sctp_sctphdr_t), (count) = 0;        \
 194         (offset) < (skb)->len &&                                        \
 195         ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch)));   \
 196         (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
 197
 198 /* Some validity checks to make sure the chunks are fine */
 199 static int do_basic_checks(struct nf_conn *ct,
 200                            const struct sk_buff *skb,
 201                            unsigned int dataoff,
 202                            unsigned long *map)
 203 {
 204         u_int32_t offset, count;
 205         sctp_chunkhdr_t _sch, *sch;
 206         int flag;
 207
 208         flag = 0;
 209
 210         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 211                 pr_debug("Chunk Num: %d  Type: %d\n", count, sch->type);
 212
 213                 if (sch->type == SCTP_CID_INIT ||
 214                     sch->type == SCTP_CID_INIT_ACK ||
 215                     sch->type == SCTP_CID_SHUTDOWN_COMPLETE)
 216                         flag = 1;
 217
 218                 /*
 219                  * Cookie Ack/Echo chunks not the first OR
 220                  * Init / Init Ack / Shutdown compl chunks not the only chunks
 221                  * OR zero-length.
 222                  */
 223                 if (((sch->type == SCTP_CID_COOKIE_ACK ||
 224                       sch->type == SCTP_CID_COOKIE_ECHO ||
 225                       flag) &&
 226                      count != 0) || !sch->length) {
 227                         pr_debug("Basic checks failed\n");
 228                         return 1;
 229                 }
 230
 231                 if (map)
 232                         set_bit(sch->type, map);
 233         }
 234
 235         pr_debug("Basic checks passed\n");
 236         return count == 0;
 237 }
 238
 239 static int sctp_new_state(enum ip_conntrack_dir dir,
 240                           enum sctp_conntrack cur_state,
 241                           int chunk_type)
 242 {
 243         int i;
 244
 245         pr_debug("Chunk type: %d\n", chunk_type);
 246
 247         switch (chunk_type) {
 248         case SCTP_CID_INIT:
 249                 pr_debug("SCTP_CID_INIT\n");
 250                 i = 0;
 251                 break;
 252         case SCTP_CID_INIT_ACK:
 253                 pr_debug("SCTP_CID_INIT_ACK\n");
 254                 i = 1;
 255                 break;
 256         case SCTP_CID_ABORT:
 257                 pr_debug("SCTP_CID_ABORT\n");
 258                 i = 2;
 259                 break;
 260         case SCTP_CID_SHUTDOWN:
 261                 pr_debug("SCTP_CID_SHUTDOWN\n");
 262                 i = 3;
 263                 break;
 264         case SCTP_CID_SHUTDOWN_ACK:
 265                 pr_debug("SCTP_CID_SHUTDOWN_ACK\n");
 266                 i = 4;
 267                 break;
 268         case SCTP_CID_ERROR:
 269                 pr_debug("SCTP_CID_ERROR\n");
 270                 i = 5;
 271                 break;
 272         case SCTP_CID_COOKIE_ECHO:
 273                 pr_debug("SCTP_CID_COOKIE_ECHO\n");
 274                 i = 6;
 275                 break;
 276         case SCTP_CID_COOKIE_ACK:
 277                 pr_debug("SCTP_CID_COOKIE_ACK\n");
 278                 i = 7;
 279                 break;
 280         case SCTP_CID_SHUTDOWN_COMPLETE:
 281                 pr_debug("SCTP_CID_SHUTDOWN_COMPLETE\n");
 282                 i = 8;
 283                 break;
 284         case SCTP_CID_HEARTBEAT:
 285                 pr_debug("SCTP_CID_HEARTBEAT");
 286                 i = 9;
 287                 break;
 288         case SCTP_CID_HEARTBEAT_ACK:
 289                 pr_debug("SCTP_CID_HEARTBEAT_ACK");
 290                 i = 10;
 291                 break;
 292         default:
 293                 /* Other chunks like DATA or SACK do not change the state */
 294                 pr_debug("Unknown chunk type, Will stay in %s\n",
 295                          sctp_conntrack_names[cur_state]);
 296                 return cur_state;
 297         }
 298
 299         pr_debug("dir: %d   cur_state: %s  chunk_type: %d  new_state: %s\n",
 300                  dir, sctp_conntrack_names[cur_state], chunk_type,
 301                  sctp_conntrack_names[sctp_conntracks[dir][i][cur_state]]);
 302
 303         return sctp_conntracks[dir][i][cur_state];
 304 }
 305
 306 static unsigned int *sctp_get_timeouts(struct net *net)
 307 {
 308         return sctp_pernet(net)->timeouts;
 309 }
 310
 311 /* Returns verdict for packet, or -NF_ACCEPT for invalid. */
 312 static int sctp_packet(struct nf_conn *ct,
 313                        const struct sk_buff *skb,
 314                        unsigned int dataoff,
 315                        enum ip_conntrack_info ctinfo,
 316                        u_int8_t pf,
 317                        unsigned int hooknum,
 318                        unsigned int *timeouts)
 319 {
 320         enum sctp_conntrack new_state, old_state;
 321         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 322         const struct sctphdr *sh;
 323         struct sctphdr _sctph;
 324         const struct sctp_chunkhdr *sch;
 325         struct sctp_chunkhdr _sch;
 326         u_int32_t offset, count;
 327         unsigned long map[256 / sizeof(unsigned long)] = { 0 };
 328
 329         sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
 330         if (sh == NULL)
 331                 goto out;
 332
 333         if (do_basic_checks(ct, skb, dataoff, map) != 0)
 334                 goto out;
 335
 336         /* Check the verification tag (Sec 8.5) */
 337         if (!test_bit(SCTP_CID_INIT, map) &&
 338             !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) &&
 339             !test_bit(SCTP_CID_COOKIE_ECHO, map) &&
 340             !test_bit(SCTP_CID_ABORT, map) &&
 341             !test_bit(SCTP_CID_SHUTDOWN_ACK, map) &&
 342             !test_bit(SCTP_CID_HEARTBEAT, map) &&
 343             !test_bit(SCTP_CID_HEARTBEAT_ACK, map) &&
 344             sh->vtag != ct->proto.sctp.vtag[dir]) {
 345                 pr_debug("Verification tag check failed\n");
 346                 goto out;
 347         }
 348
 349         old_state = new_state = SCTP_CONNTRACK_NONE;
 350         spin_lock_bh(&ct->lock);
 351         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 352                 /* Special cases of Verification tag check (Sec 8.5.1) */
 353                 if (sch->type == SCTP_CID_INIT) {
 354                         /* Sec 8.5.1 (A) */
 355                         if (sh->vtag != 0)
 356                                 goto out_unlock;
 357                 } else if (sch->type == SCTP_CID_ABORT) {
 358                         /* Sec 8.5.1 (B) */
 359                         if (sh->vtag != ct->proto.sctp.vtag[dir] &&
 360                             sh->vtag != ct->proto.sctp.vtag[!dir])
 361                                 goto out_unlock;
 362                 } else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
 363                         /* Sec 8.5.1 (C) */
 364                         if (sh->vtag != ct->proto.sctp.vtag[dir] &&
 365                             sh->vtag != ct->proto.sctp.vtag[!dir] &&
 366                             sch->flags & SCTP_CHUNK_FLAG_T)
 367                                 goto out_unlock;
 368                 } else if (sch->type == SCTP_CID_COOKIE_ECHO) {
 369                         /* Sec 8.5.1 (D) */
 370                         if (sh->vtag != ct->proto.sctp.vtag[dir])
 371                                 goto out_unlock;
 372                 } else if (sch->type == SCTP_CID_HEARTBEAT ||
 373                            sch->type == SCTP_CID_HEARTBEAT_ACK) {
 374                         if (ct->proto.sctp.vtag[dir] == 0) {
 375                                 pr_debug("Setting vtag %x for dir %d\n",
 376                                          sh->vtag, dir);
 377                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 378                         } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
 379                                 pr_debug("Verification tag check failed\n");
 380                                 goto out_unlock;
 381                         }
 382                 }
 383
 384                 old_state = ct->proto.sctp.state;
 385                 new_state = sctp_new_state(dir, old_state, sch->type);
 386
 387                 /* Invalid */
 388                 if (new_state == SCTP_CONNTRACK_MAX) {
 389                         pr_debug("nf_conntrack_sctp: Invalid dir=%i ctype=%u "
 390                                  "conntrack=%u\n",
 391                                  dir, sch->type, old_state);
 392                         goto out_unlock;
 393                 }
 394
 395                 /* If it is an INIT or an INIT ACK note down the vtag */
 396                 if (sch->type == SCTP_CID_INIT ||
 397                     sch->type == SCTP_CID_INIT_ACK) {
 398                         sctp_inithdr_t _inithdr, *ih;
 399
 400                         ih = skb_header_pointer(skb, offset + sizeof(sctp_chunkhdr_t),
 401                                                 sizeof(_inithdr), &_inithdr);
 402                         if (ih == NULL)
 403                                 goto out_unlock;
 404                         pr_debug("Setting vtag %x for dir %d\n",
 405                                  ih->init_tag, !dir);
 406                         ct->proto.sctp.vtag[!dir] = ih->init_tag;
 407                 }
 408
 409                 ct->proto.sctp.state = new_state;
 410                 if (old_state != new_state)
 411                         nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
 412         }
 413         spin_unlock_bh(&ct->lock);
 414
 415         nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);
 416
 417         if (old_state == SCTP_CONNTRACK_COOKIE_ECHOED &&
 418             dir == IP_CT_DIR_REPLY &&
 419             new_state == SCTP_CONNTRACK_ESTABLISHED) {
 420                 pr_debug("Setting assured bit\n");
 421                 set_bit(IPS_ASSURED_BIT, &ct->status);
 422                 nf_conntrack_event_cache(IPCT_ASSURED, ct);
 423         }
 424
 425         return NF_ACCEPT;
 426
 427 out_unlock:
 428         spin_unlock_bh(&ct->lock);
 429 out:
 430         return -NF_ACCEPT;
 431 }
 432
 433 /* Called when a new connection for this protocol found. */
 434 static bool sctp_new(struct nf_conn *ct, const struct sk_buff *skb,
 435                      unsigned int dataoff, unsigned int *timeouts)
 436 {
 437         enum sctp_conntrack new_state;
 438         const struct sctphdr *sh;
 439         struct sctphdr _sctph;
 440         const struct sctp_chunkhdr *sch;
 441         struct sctp_chunkhdr _sch;
 442         u_int32_t offset, count;
 443         unsigned long map[256 / sizeof(unsigned long)] = { 0 };
 444
 445         sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
 446         if (sh == NULL)
 447                 return false;
 448
 449         if (do_basic_checks(ct, skb, dataoff, map) != 0)
 450                 return false;
 451
 452         /* If an OOTB packet has any of these chunks discard (Sec 8.4) */
 453         if (test_bit(SCTP_CID_ABORT, map) ||
 454             test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) ||
 455             test_bit(SCTP_CID_COOKIE_ACK, map))
 456                 return false;
 457
 458         memset(&ct->proto.sctp, 0, sizeof(ct->proto.sctp));
 459         new_state = SCTP_CONNTRACK_MAX;
 460         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 461                 /* Don't need lock here: this conntrack not in circulation yet */
 462                 new_state = sctp_new_state(IP_CT_DIR_ORIGINAL,
 463                                            SCTP_CONNTRACK_NONE, sch->type);
 464
 465                 /* Invalid: delete conntrack */
 466                 if (new_state == SCTP_CONNTRACK_NONE ||
 467                     new_state == SCTP_CONNTRACK_MAX) {
 468                         pr_debug("nf_conntrack_sctp: invalid new deleting.\n");
 469                         return false;
 470                 }
 471
 472                 /* Copy the vtag into the state info */
 473                 if (sch->type == SCTP_CID_INIT) {
 474                         if (sh->vtag == 0) {
 475                                 sctp_inithdr_t _inithdr, *ih;
 476
 477                                 ih = skb_header_pointer(skb, offset + sizeof(sctp_chunkhdr_t),
 478                                                         sizeof(_inithdr), &_inithdr);
 479                                 if (ih == NULL)
 480                                         return false;
 481
 482                                 pr_debug("Setting vtag %x for new conn\n",
 483                                          ih->init_tag);
 484
 485                                 ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
 486                                                                 ih->init_tag;
 487                         } else {
 488                                 /* Sec 8.5.1 (A) */
 489                                 return false;
 490                         }
 491                 } else if (sch->type == SCTP_CID_HEARTBEAT) {
 492                         pr_debug("Setting vtag %x for secondary conntrack\n",
 493                                  sh->vtag);
 494                         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] = sh->vtag;
 495                 }
 496                 /* If it is a shutdown ack OOTB packet, we expect a return
 497                    shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
 498                 else {
 499                         pr_debug("Setting vtag %x for new conn OOTB\n",
 500                                  sh->vtag);
 501                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
 502                 }
 503
 504                 ct->proto.sctp.state = new_state;
 505         }
 506
 507         return true;
 508 }
 509
 510 static int sctp_error(struct net *net, struct nf_conn *tpl, struct sk_buff *skb,
 511                       unsigned int dataoff,
 512                       u8 pf, unsigned int hooknum)
 513 {
 514         const struct sctphdr *sh;
 515         const char *logmsg;
 516
 517         if (skb->len < dataoff + sizeof(struct sctphdr)) {
 518                 logmsg = "nf_ct_sctp: short packet ";
 519                 goto out_invalid;
 520         }
 521         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 522             skb->ip_summed == CHECKSUM_NONE) {
 523                 if (!skb_make_writable(skb, dataoff + sizeof(struct sctphdr))) {
 524                         logmsg = "nf_ct_sctp: failed to read header ";
 525                         goto out_invalid;
 526                 }
 527                 sh = (const struct sctphdr *)(skb->data + dataoff);
 528                 if (sh->checksum != sctp_compute_cksum(skb, dataoff)) {
 529                         logmsg = "nf_ct_sctp: bad CRC ";
 530                         goto out_invalid;
 531                 }
 532                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 533         }
 534         return NF_ACCEPT;
 535 out_invalid:
 536         if (LOG_INVALID(net, IPPROTO_SCTP))
 537                 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL, "%s", logmsg);
 538         return -NF_ACCEPT;
 539 }
 540
 541 static bool sctp_can_early_drop(const struct nf_conn *ct)
 542 {
 543         switch (ct->proto.sctp.state) {
 544         case SCTP_CONNTRACK_SHUTDOWN_SENT:
 545         case SCTP_CONNTRACK_SHUTDOWN_RECD:
 546         case SCTP_CONNTRACK_SHUTDOWN_ACK_SENT:
 547                 return true;
 548         default:
 549                 break;
 550         }
 551
 552         return false;
 553 }
 554
 555 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 556
 557 #include <linux/netfilter/nfnetlink.h>
 558 #include <linux/netfilter/nfnetlink_conntrack.h>
 559
 560 static int sctp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 561                           struct nf_conn *ct)
 562 {
 563         struct nlattr *nest_parms;
 564
 565         spin_lock_bh(&ct->lock);
 566         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_SCTP | NLA_F_NESTED);
 567         if (!nest_parms)
 568                 goto nla_put_failure;
 569
 570         if (nla_put_u8(skb, CTA_PROTOINFO_SCTP_STATE, ct->proto.sctp.state) ||
 571             nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_ORIGINAL,
 572                          ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL]) ||
 573             nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_REPLY,
 574                          ct->proto.sctp.vtag[IP_CT_DIR_REPLY]))
 575                 goto nla_put_failure;
 576
 577         spin_unlock_bh(&ct->lock);
 578
 579         nla_nest_end(skb, nest_parms);
 580
 581         return 0;
 582
 583 nla_put_failure:
 584         spin_unlock_bh(&ct->lock);
 585         return -1;
 586 }
 587
 588 static const struct nla_policy sctp_nla_policy[CTA_PROTOINFO_SCTP_MAX+1] = {
 589         [CTA_PROTOINFO_SCTP_STATE]          = { .type = NLA_U8 },
 590         [CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]  = { .type = NLA_U32 },
 591         [CTA_PROTOINFO_SCTP_VTAG_REPLY]     = { .type = NLA_U32 },
 592 };
 593
 594 static int nlattr_to_sctp(struct nlattr *cda[], struct nf_conn *ct)
 595 {
 596         struct nlattr *attr = cda[CTA_PROTOINFO_SCTP];
 597         struct nlattr *tb[CTA_PROTOINFO_SCTP_MAX+1];
 598         int err;
 599
 600         /* updates may not contain the internal protocol info, skip parsing */
 601         if (!attr)
 602                 return 0;
 603
 604         err = nla_parse_nested(tb, CTA_PROTOINFO_SCTP_MAX, attr,
 605                                sctp_nla_policy, NULL);
 606         if (err < 0)
 607                 return err;
 608
 609         if (!tb[CTA_PROTOINFO_SCTP_STATE] ||
 610             !tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL] ||
 611             !tb[CTA_PROTOINFO_SCTP_VTAG_REPLY])
 612                 return -EINVAL;
 613
 614         spin_lock_bh(&ct->lock);
 615         ct->proto.sctp.state = nla_get_u8(tb[CTA_PROTOINFO_SCTP_STATE]);
 616         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] =
 617                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]);
 618         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
 619                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_REPLY]);
 620         spin_unlock_bh(&ct->lock);
 621
 622         return 0;
 623 }
 624
 625 static int sctp_nlattr_size(void)
 626 {
 627         return nla_total_size(0)        /* CTA_PROTOINFO_SCTP */
 628                 + nla_policy_len(sctp_nla_policy, CTA_PROTOINFO_SCTP_MAX + 1);
 629 }
 630 #endif
 631
 632 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 633
 634 #include <linux/netfilter/nfnetlink.h>
 635 #include <linux/netfilter/nfnetlink_cttimeout.h>
 636
 637 static int sctp_timeout_nlattr_to_obj(struct nlattr *tb[],
 638                                       struct net *net, void *data)
 639 {
 640         unsigned int *timeouts = data;
 641         struct nf_sctp_net *sn = sctp_pernet(net);
 642         int i;
 643
 644         /* set default SCTP timeouts. */
 645         for (i=0; i<SCTP_CONNTRACK_MAX; i++)
 646                 timeouts[i] = sn->timeouts[i];
 647
 648         /* there's a 1:1 mapping between attributes and protocol states. */
 649         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 650                 if (tb[i]) {
 651                         timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
 652                 }
 653         }
 654         return 0;
 655 }
 656
 657 static int
 658 sctp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 659 {
 660         const unsigned int *timeouts = data;
 661         int i;
 662
 663         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 664                 if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
 665                         goto nla_put_failure;
 666         }
 667         return 0;
 668
 669 nla_put_failure:
 670         return -ENOSPC;
 671 }
 672
 673 static const struct nla_policy
 674 sctp_timeout_nla_policy[CTA_TIMEOUT_SCTP_MAX+1] = {
 675         [CTA_TIMEOUT_SCTP_CLOSED]               = { .type = NLA_U32 },
 676         [CTA_TIMEOUT_SCTP_COOKIE_WAIT]          = { .type = NLA_U32 },
 677         [CTA_TIMEOUT_SCTP_COOKIE_ECHOED]        = { .type = NLA_U32 },
 678         [CTA_TIMEOUT_SCTP_ESTABLISHED]          = { .type = NLA_U32 },
 679         [CTA_TIMEOUT_SCTP_SHUTDOWN_SENT]        = { .type = NLA_U32 },
 680         [CTA_TIMEOUT_SCTP_SHUTDOWN_RECD]        = { .type = NLA_U32 },
 681         [CTA_TIMEOUT_SCTP_SHUTDOWN_ACK_SENT]    = { .type = NLA_U32 },
 682         [CTA_TIMEOUT_SCTP_HEARTBEAT_SENT]       = { .type = NLA_U32 },
 683         [CTA_TIMEOUT_SCTP_HEARTBEAT_ACKED]      = { .type = NLA_U32 },
 684 };
 685 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 686
 687
 688 #ifdef CONFIG_SYSCTL
 689 static struct ctl_table sctp_sysctl_table[] = {
 690         {
 691                 .procname       = "nf_conntrack_sctp_timeout_closed",
 692                 .maxlen         = sizeof(unsigned int),
 693                 .mode           = 0644,
 694                 .proc_handler   = proc_dointvec_jiffies,
 695         },
 696         {
 697                 .procname       = "nf_conntrack_sctp_timeout_cookie_wait",
 698                 .maxlen         = sizeof(unsigned int),
 699                 .mode           = 0644,
 700                 .proc_handler   = proc_dointvec_jiffies,
 701         },
 702         {
 703                 .procname       = "nf_conntrack_sctp_timeout_cookie_echoed",
 704                 .maxlen         = sizeof(unsigned int),
 705                 .mode           = 0644,
 706                 .proc_handler   = proc_dointvec_jiffies,
 707         },
 708         {
 709                 .procname       = "nf_conntrack_sctp_timeout_established",
 710                 .maxlen         = sizeof(unsigned int),
 711                 .mode           = 0644,
 712                 .proc_handler   = proc_dointvec_jiffies,
 713         },
 714         {
 715                 .procname       = "nf_conntrack_sctp_timeout_shutdown_sent",
 716                 .maxlen         = sizeof(unsigned int),
 717                 .mode           = 0644,
 718                 .proc_handler   = proc_dointvec_jiffies,
 719         },
 720         {
 721                 .procname       = "nf_conntrack_sctp_timeout_shutdown_recd",
 722                 .maxlen         = sizeof(unsigned int),
 723                 .mode           = 0644,
 724                 .proc_handler   = proc_dointvec_jiffies,
 725         },
 726         {
 727                 .procname       = "nf_conntrack_sctp_timeout_shutdown_ack_sent",
 728                 .maxlen         = sizeof(unsigned int),
 729                 .mode           = 0644,
 730                 .proc_handler   = proc_dointvec_jiffies,
 731         },
 732         {
 733                 .procname       = "nf_conntrack_sctp_timeout_heartbeat_sent",
 734                 .maxlen         = sizeof(unsigned int),
 735                 .mode           = 0644,
 736                 .proc_handler   = proc_dointvec_jiffies,
 737         },
 738         {
 739                 .procname       = "nf_conntrack_sctp_timeout_heartbeat_acked",
 740                 .maxlen         = sizeof(unsigned int),
 741                 .mode           = 0644,
 742                 .proc_handler   = proc_dointvec_jiffies,
 743         },
 744         { }
 745 };
 746 #endif
 747
 748 static int sctp_kmemdup_sysctl_table(struct nf_proto_net *pn,
 749                                      struct nf_sctp_net *sn)
 750 {
 751 #ifdef CONFIG_SYSCTL
 752         if (pn->ctl_table)
 753                 return 0;
 754
 755         pn->ctl_table = kmemdup(sctp_sysctl_table,
 756                                 sizeof(sctp_sysctl_table),
 757                                 GFP_KERNEL);
 758         if (!pn->ctl_table)
 759                 return -ENOMEM;
 760
 761         pn->ctl_table[0].data = &sn->timeouts[SCTP_CONNTRACK_CLOSED];
 762         pn->ctl_table[1].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_WAIT];
 763         pn->ctl_table[2].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_ECHOED];
 764         pn->ctl_table[3].data = &sn->timeouts[SCTP_CONNTRACK_ESTABLISHED];
 765         pn->ctl_table[4].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_SENT];
 766         pn->ctl_table[5].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_RECD];
 767         pn->ctl_table[6].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_ACK_SENT];
 768         pn->ctl_table[7].data = &sn->timeouts[SCTP_CONNTRACK_HEARTBEAT_SENT];
 769         pn->ctl_table[8].data = &sn->timeouts[SCTP_CONNTRACK_HEARTBEAT_ACKED];
 770 #endif
 771         return 0;
 772 }
 773
 774 static int sctp_init_net(struct net *net, u_int16_t proto)
 775 {
 776         struct nf_sctp_net *sn = sctp_pernet(net);
 777         struct nf_proto_net *pn = &sn->pn;
 778
 779         if (!pn->users) {
 780                 int i;
 781
 782                 for (i = 0; i < SCTP_CONNTRACK_MAX; i++)
 783                         sn->timeouts[i] = sctp_timeouts[i];
 784         }
 785
 786         return sctp_kmemdup_sysctl_table(pn, sn);
 787 }
 788
 789 struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp4 __read_mostly = {
 790         .l3proto                = PF_INET,
 791         .l4proto                = IPPROTO_SCTP,
 792         .name                   = "sctp",
 793         .pkt_to_tuple           = sctp_pkt_to_tuple,
 794         .invert_tuple           = sctp_invert_tuple,
 795         .print_tuple            = sctp_print_tuple,
 796         .print_conntrack        = sctp_print_conntrack,
 797         .packet                 = sctp_packet,
 798         .get_timeouts           = sctp_get_timeouts,
 799         .new                    = sctp_new,
 800         .error                  = sctp_error,
 801         .can_early_drop         = sctp_can_early_drop,
 802         .me                     = THIS_MODULE,
 803 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 804         .to_nlattr              = sctp_to_nlattr,
 805         .nlattr_size            = sctp_nlattr_size,
 806         .from_nlattr            = nlattr_to_sctp,
 807         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 808         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 809         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 810         .nla_policy             = nf_ct_port_nla_policy,
 811 #endif
 812 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 813         .ctnl_timeout           = {
 814                 .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
 815                 .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
 816                 .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
 817                 .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
 818                 .nla_policy     = sctp_timeout_nla_policy,
 819         },
 820 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 821         .init_net               = sctp_init_net,
 822 };
 823 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_sctp4);
 824
 825 struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp6 __read_mostly = {
 826         .l3proto                = PF_INET6,
 827         .l4proto                = IPPROTO_SCTP,
 828         .name                   = "sctp",
 829         .pkt_to_tuple           = sctp_pkt_to_tuple,
 830         .invert_tuple           = sctp_invert_tuple,
 831         .print_tuple            = sctp_print_tuple,
 832         .print_conntrack        = sctp_print_conntrack,
 833         .packet                 = sctp_packet,
 834         .get_timeouts           = sctp_get_timeouts,
 835         .new                    = sctp_new,
 836         .error                  = sctp_error,
 837         .can_early_drop         = sctp_can_early_drop,
 838         .me                     = THIS_MODULE,
 839 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 840         .to_nlattr              = sctp_to_nlattr,
 841         .nlattr_size            = sctp_nlattr_size,
 842         .from_nlattr            = nlattr_to_sctp,
 843         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 844         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 845         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 846         .nla_policy             = nf_ct_port_nla_policy,
 847 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 848         .ctnl_timeout           = {
 849                 .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
 850                 .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
 851                 .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
 852                 .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
 853                 .nla_policy     = sctp_timeout_nla_policy,
 854         },
 855 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 856 #endif
 857         .init_net               = sctp_init_net,
 858 };
 859 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_sctp6);