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 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 178 /* Print out the private part of the conntrack. */
 179 static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 180 {
 181         seq_printf(s, "%s ", sctp_conntrack_names[ct->proto.sctp.state]);
 182 }
 183 #endif
 184
 185 #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count)     \
 186 for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0;        \
 187         (offset) < (skb)->len &&                                        \
 188         ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch)));   \
 189         (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
 190
 191 /* Some validity checks to make sure the chunks are fine */
 192 static int do_basic_checks(struct nf_conn *ct,
 193                            const struct sk_buff *skb,
 194                            unsigned int dataoff,
 195                            unsigned long *map)
 196 {
 197         u_int32_t offset, count;
 198         struct sctp_chunkhdr _sch, *sch;
 199         int flag;
 200
 201         flag = 0;
 202
 203         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 204                 pr_debug("Chunk Num: %d  Type: %d\n", count, sch->type);
 205
 206                 if (sch->type == SCTP_CID_INIT ||
 207                     sch->type == SCTP_CID_INIT_ACK ||
 208                     sch->type == SCTP_CID_SHUTDOWN_COMPLETE)
 209                         flag = 1;
 210
 211                 /*
 212                  * Cookie Ack/Echo chunks not the first OR
 213                  * Init / Init Ack / Shutdown compl chunks not the only chunks
 214                  * OR zero-length.
 215                  */
 216                 if (((sch->type == SCTP_CID_COOKIE_ACK ||
 217                       sch->type == SCTP_CID_COOKIE_ECHO ||
 218                       flag) &&
 219                      count != 0) || !sch->length) {
 220                         pr_debug("Basic checks failed\n");
 221                         return 1;
 222                 }
 223
 224                 if (map)
 225                         set_bit(sch->type, map);
 226         }
 227
 228         pr_debug("Basic checks passed\n");
 229         return count == 0;
 230 }
 231
 232 static int sctp_new_state(enum ip_conntrack_dir dir,
 233                           enum sctp_conntrack cur_state,
 234                           int chunk_type)
 235 {
 236         int i;
 237
 238         pr_debug("Chunk type: %d\n", chunk_type);
 239
 240         switch (chunk_type) {
 241         case SCTP_CID_INIT:
 242                 pr_debug("SCTP_CID_INIT\n");
 243                 i = 0;
 244                 break;
 245         case SCTP_CID_INIT_ACK:
 246                 pr_debug("SCTP_CID_INIT_ACK\n");
 247                 i = 1;
 248                 break;
 249         case SCTP_CID_ABORT:
 250                 pr_debug("SCTP_CID_ABORT\n");
 251                 i = 2;
 252                 break;
 253         case SCTP_CID_SHUTDOWN:
 254                 pr_debug("SCTP_CID_SHUTDOWN\n");
 255                 i = 3;
 256                 break;
 257         case SCTP_CID_SHUTDOWN_ACK:
 258                 pr_debug("SCTP_CID_SHUTDOWN_ACK\n");
 259                 i = 4;
 260                 break;
 261         case SCTP_CID_ERROR:
 262                 pr_debug("SCTP_CID_ERROR\n");
 263                 i = 5;
 264                 break;
 265         case SCTP_CID_COOKIE_ECHO:
 266                 pr_debug("SCTP_CID_COOKIE_ECHO\n");
 267                 i = 6;
 268                 break;
 269         case SCTP_CID_COOKIE_ACK:
 270                 pr_debug("SCTP_CID_COOKIE_ACK\n");
 271                 i = 7;
 272                 break;
 273         case SCTP_CID_SHUTDOWN_COMPLETE:
 274                 pr_debug("SCTP_CID_SHUTDOWN_COMPLETE\n");
 275                 i = 8;
 276                 break;
 277         case SCTP_CID_HEARTBEAT:
 278                 pr_debug("SCTP_CID_HEARTBEAT");
 279                 i = 9;
 280                 break;
 281         case SCTP_CID_HEARTBEAT_ACK:
 282                 pr_debug("SCTP_CID_HEARTBEAT_ACK");
 283                 i = 10;
 284                 break;
 285         default:
 286                 /* Other chunks like DATA or SACK do not change the state */
 287                 pr_debug("Unknown chunk type, Will stay in %s\n",
 288                          sctp_conntrack_names[cur_state]);
 289                 return cur_state;
 290         }
 291
 292         pr_debug("dir: %d   cur_state: %s  chunk_type: %d  new_state: %s\n",
 293                  dir, sctp_conntrack_names[cur_state], chunk_type,
 294                  sctp_conntrack_names[sctp_conntracks[dir][i][cur_state]]);
 295
 296         return sctp_conntracks[dir][i][cur_state];
 297 }
 298
 299 static unsigned int *sctp_get_timeouts(struct net *net)
 300 {
 301         return sctp_pernet(net)->timeouts;
 302 }
 303
 304 /* Returns verdict for packet, or -NF_ACCEPT for invalid. */
 305 static int sctp_packet(struct nf_conn *ct,
 306                        const struct sk_buff *skb,
 307                        unsigned int dataoff,
 308                        enum ip_conntrack_info ctinfo,
 309                        u_int8_t pf,
 310                        unsigned int *timeouts)
 311 {
 312         enum sctp_conntrack new_state, old_state;
 313         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 314         const struct sctphdr *sh;
 315         struct sctphdr _sctph;
 316         const struct sctp_chunkhdr *sch;
 317         struct sctp_chunkhdr _sch;
 318         u_int32_t offset, count;
 319         unsigned long map[256 / sizeof(unsigned long)] = { 0 };
 320
 321         sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
 322         if (sh == NULL)
 323                 goto out;
 324
 325         if (do_basic_checks(ct, skb, dataoff, map) != 0)
 326                 goto out;
 327
 328         /* Check the verification tag (Sec 8.5) */
 329         if (!test_bit(SCTP_CID_INIT, map) &&
 330             !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) &&
 331             !test_bit(SCTP_CID_COOKIE_ECHO, map) &&
 332             !test_bit(SCTP_CID_ABORT, map) &&
 333             !test_bit(SCTP_CID_SHUTDOWN_ACK, map) &&
 334             !test_bit(SCTP_CID_HEARTBEAT, map) &&
 335             !test_bit(SCTP_CID_HEARTBEAT_ACK, map) &&
 336             sh->vtag != ct->proto.sctp.vtag[dir]) {
 337                 pr_debug("Verification tag check failed\n");
 338                 goto out;
 339         }
 340
 341         old_state = new_state = SCTP_CONNTRACK_NONE;
 342         spin_lock_bh(&ct->lock);
 343         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 344                 /* Special cases of Verification tag check (Sec 8.5.1) */
 345                 if (sch->type == SCTP_CID_INIT) {
 346                         /* Sec 8.5.1 (A) */
 347                         if (sh->vtag != 0)
 348                                 goto out_unlock;
 349                 } else if (sch->type == SCTP_CID_ABORT) {
 350                         /* Sec 8.5.1 (B) */
 351                         if (sh->vtag != ct->proto.sctp.vtag[dir] &&
 352                             sh->vtag != ct->proto.sctp.vtag[!dir])
 353                                 goto out_unlock;
 354                 } else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
 355                         /* Sec 8.5.1 (C) */
 356                         if (sh->vtag != ct->proto.sctp.vtag[dir] &&
 357                             sh->vtag != ct->proto.sctp.vtag[!dir] &&
 358                             sch->flags & SCTP_CHUNK_FLAG_T)
 359                                 goto out_unlock;
 360                 } else if (sch->type == SCTP_CID_COOKIE_ECHO) {
 361                         /* Sec 8.5.1 (D) */
 362                         if (sh->vtag != ct->proto.sctp.vtag[dir])
 363                                 goto out_unlock;
 364                 } else if (sch->type == SCTP_CID_HEARTBEAT ||
 365                            sch->type == SCTP_CID_HEARTBEAT_ACK) {
 366                         if (ct->proto.sctp.vtag[dir] == 0) {
 367                                 pr_debug("Setting vtag %x for dir %d\n",
 368                                          sh->vtag, dir);
 369                                 ct->proto.sctp.vtag[dir] = sh->vtag;
 370                         } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
 371                                 pr_debug("Verification tag check failed\n");
 372                                 goto out_unlock;
 373                         }
 374                 }
 375
 376                 old_state = ct->proto.sctp.state;
 377                 new_state = sctp_new_state(dir, old_state, sch->type);
 378
 379                 /* Invalid */
 380                 if (new_state == SCTP_CONNTRACK_MAX) {
 381                         pr_debug("nf_conntrack_sctp: Invalid dir=%i ctype=%u "
 382                                  "conntrack=%u\n",
 383                                  dir, sch->type, old_state);
 384                         goto out_unlock;
 385                 }
 386
 387                 /* If it is an INIT or an INIT ACK note down the vtag */
 388                 if (sch->type == SCTP_CID_INIT ||
 389                     sch->type == SCTP_CID_INIT_ACK) {
 390                         struct sctp_inithdr _inithdr, *ih;
 391
 392                         ih = skb_header_pointer(skb, offset + sizeof(_sch),
 393                                                 sizeof(_inithdr), &_inithdr);
 394                         if (ih == NULL)
 395                                 goto out_unlock;
 396                         pr_debug("Setting vtag %x for dir %d\n",
 397                                  ih->init_tag, !dir);
 398                         ct->proto.sctp.vtag[!dir] = ih->init_tag;
 399                 }
 400
 401                 ct->proto.sctp.state = new_state;
 402                 if (old_state != new_state)
 403                         nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
 404         }
 405         spin_unlock_bh(&ct->lock);
 406
 407         nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);
 408
 409         if (old_state == SCTP_CONNTRACK_COOKIE_ECHOED &&
 410             dir == IP_CT_DIR_REPLY &&
 411             new_state == SCTP_CONNTRACK_ESTABLISHED) {
 412                 pr_debug("Setting assured bit\n");
 413                 set_bit(IPS_ASSURED_BIT, &ct->status);
 414                 nf_conntrack_event_cache(IPCT_ASSURED, ct);
 415         }
 416
 417         return NF_ACCEPT;
 418
 419 out_unlock:
 420         spin_unlock_bh(&ct->lock);
 421 out:
 422         return -NF_ACCEPT;
 423 }
 424
 425 /* Called when a new connection for this protocol found. */
 426 static bool sctp_new(struct nf_conn *ct, const struct sk_buff *skb,
 427                      unsigned int dataoff, unsigned int *timeouts)
 428 {
 429         enum sctp_conntrack new_state;
 430         const struct sctphdr *sh;
 431         struct sctphdr _sctph;
 432         const struct sctp_chunkhdr *sch;
 433         struct sctp_chunkhdr _sch;
 434         u_int32_t offset, count;
 435         unsigned long map[256 / sizeof(unsigned long)] = { 0 };
 436
 437         sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
 438         if (sh == NULL)
 439                 return false;
 440
 441         if (do_basic_checks(ct, skb, dataoff, map) != 0)
 442                 return false;
 443
 444         /* If an OOTB packet has any of these chunks discard (Sec 8.4) */
 445         if (test_bit(SCTP_CID_ABORT, map) ||
 446             test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) ||
 447             test_bit(SCTP_CID_COOKIE_ACK, map))
 448                 return false;
 449
 450         memset(&ct->proto.sctp, 0, sizeof(ct->proto.sctp));
 451         new_state = SCTP_CONNTRACK_MAX;
 452         for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 453                 /* Don't need lock here: this conntrack not in circulation yet */
 454                 new_state = sctp_new_state(IP_CT_DIR_ORIGINAL,
 455                                            SCTP_CONNTRACK_NONE, sch->type);
 456
 457                 /* Invalid: delete conntrack */
 458                 if (new_state == SCTP_CONNTRACK_NONE ||
 459                     new_state == SCTP_CONNTRACK_MAX) {
 460                         pr_debug("nf_conntrack_sctp: invalid new deleting.\n");
 461                         return false;
 462                 }
 463
 464                 /* Copy the vtag into the state info */
 465                 if (sch->type == SCTP_CID_INIT) {
 466                         struct sctp_inithdr _inithdr, *ih;
 467                         /* Sec 8.5.1 (A) */
 468                         if (sh->vtag)
 469                                 return false;
 470
 471                         ih = skb_header_pointer(skb, offset + sizeof(_sch),
 472                                                 sizeof(_inithdr), &_inithdr);
 473                         if (!ih)
 474                                 return false;
 475
 476                         pr_debug("Setting vtag %x for new conn\n",
 477                                  ih->init_tag);
 478
 479                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = ih->init_tag;
 480                 } else if (sch->type == SCTP_CID_HEARTBEAT) {
 481                         pr_debug("Setting vtag %x for secondary conntrack\n",
 482                                  sh->vtag);
 483                         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] = sh->vtag;
 484                 }
 485                 /* If it is a shutdown ack OOTB packet, we expect a return
 486                    shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
 487                 else {
 488                         pr_debug("Setting vtag %x for new conn OOTB\n",
 489                                  sh->vtag);
 490                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
 491                 }
 492
 493                 ct->proto.sctp.state = new_state;
 494         }
 495
 496         return true;
 497 }
 498
 499 static int sctp_error(struct net *net, struct nf_conn *tpl, struct sk_buff *skb,
 500                       unsigned int dataoff,
 501                       u8 pf, unsigned int hooknum)
 502 {
 503         const struct sctphdr *sh;
 504         const char *logmsg;
 505
 506         if (skb->len < dataoff + sizeof(struct sctphdr)) {
 507                 logmsg = "nf_ct_sctp: short packet ";
 508                 goto out_invalid;
 509         }
 510         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 511             skb->ip_summed == CHECKSUM_NONE) {
 512                 if (!skb_make_writable(skb, dataoff + sizeof(struct sctphdr))) {
 513                         logmsg = "nf_ct_sctp: failed to read header ";
 514                         goto out_invalid;
 515                 }
 516                 sh = (const struct sctphdr *)(skb->data + dataoff);
 517                 if (sh->checksum != sctp_compute_cksum(skb, dataoff)) {
 518                         logmsg = "nf_ct_sctp: bad CRC ";
 519                         goto out_invalid;
 520                 }
 521                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 522         }
 523         return NF_ACCEPT;
 524 out_invalid:
 525         if (LOG_INVALID(net, IPPROTO_SCTP))
 526                 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL, "%s", logmsg);
 527         return -NF_ACCEPT;
 528 }
 529
 530 static bool sctp_can_early_drop(const struct nf_conn *ct)
 531 {
 532         switch (ct->proto.sctp.state) {
 533         case SCTP_CONNTRACK_SHUTDOWN_SENT:
 534         case SCTP_CONNTRACK_SHUTDOWN_RECD:
 535         case SCTP_CONNTRACK_SHUTDOWN_ACK_SENT:
 536                 return true;
 537         default:
 538                 break;
 539         }
 540
 541         return false;
 542 }
 543
 544 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 545
 546 #include <linux/netfilter/nfnetlink.h>
 547 #include <linux/netfilter/nfnetlink_conntrack.h>
 548
 549 static int sctp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 550                           struct nf_conn *ct)
 551 {
 552         struct nlattr *nest_parms;
 553
 554         spin_lock_bh(&ct->lock);
 555         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_SCTP | NLA_F_NESTED);
 556         if (!nest_parms)
 557                 goto nla_put_failure;
 558
 559         if (nla_put_u8(skb, CTA_PROTOINFO_SCTP_STATE, ct->proto.sctp.state) ||
 560             nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_ORIGINAL,
 561                          ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL]) ||
 562             nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_REPLY,
 563                          ct->proto.sctp.vtag[IP_CT_DIR_REPLY]))
 564                 goto nla_put_failure;
 565
 566         spin_unlock_bh(&ct->lock);
 567
 568         nla_nest_end(skb, nest_parms);
 569
 570         return 0;
 571
 572 nla_put_failure:
 573         spin_unlock_bh(&ct->lock);
 574         return -1;
 575 }
 576
 577 static const struct nla_policy sctp_nla_policy[CTA_PROTOINFO_SCTP_MAX+1] = {
 578         [CTA_PROTOINFO_SCTP_STATE]          = { .type = NLA_U8 },
 579         [CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]  = { .type = NLA_U32 },
 580         [CTA_PROTOINFO_SCTP_VTAG_REPLY]     = { .type = NLA_U32 },
 581 };
 582
 583 static int nlattr_to_sctp(struct nlattr *cda[], struct nf_conn *ct)
 584 {
 585         struct nlattr *attr = cda[CTA_PROTOINFO_SCTP];
 586         struct nlattr *tb[CTA_PROTOINFO_SCTP_MAX+1];
 587         int err;
 588
 589         /* updates may not contain the internal protocol info, skip parsing */
 590         if (!attr)
 591                 return 0;
 592
 593         err = nla_parse_nested(tb, CTA_PROTOINFO_SCTP_MAX, attr,
 594                                sctp_nla_policy, NULL);
 595         if (err < 0)
 596                 return err;
 597
 598         if (!tb[CTA_PROTOINFO_SCTP_STATE] ||
 599             !tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL] ||
 600             !tb[CTA_PROTOINFO_SCTP_VTAG_REPLY])
 601                 return -EINVAL;
 602
 603         spin_lock_bh(&ct->lock);
 604         ct->proto.sctp.state = nla_get_u8(tb[CTA_PROTOINFO_SCTP_STATE]);
 605         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] =
 606                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]);
 607         ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
 608                 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_REPLY]);
 609         spin_unlock_bh(&ct->lock);
 610
 611         return 0;
 612 }
 613
 614 static int sctp_nlattr_size(void)
 615 {
 616         return nla_total_size(0)        /* CTA_PROTOINFO_SCTP */
 617                 + nla_policy_len(sctp_nla_policy, CTA_PROTOINFO_SCTP_MAX + 1);
 618 }
 619 #endif
 620
 621 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 622
 623 #include <linux/netfilter/nfnetlink.h>
 624 #include <linux/netfilter/nfnetlink_cttimeout.h>
 625
 626 static int sctp_timeout_nlattr_to_obj(struct nlattr *tb[],
 627                                       struct net *net, void *data)
 628 {
 629         unsigned int *timeouts = data;
 630         struct nf_sctp_net *sn = sctp_pernet(net);
 631         int i;
 632
 633         /* set default SCTP timeouts. */
 634         for (i=0; i<SCTP_CONNTRACK_MAX; i++)
 635                 timeouts[i] = sn->timeouts[i];
 636
 637         /* there's a 1:1 mapping between attributes and protocol states. */
 638         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 639                 if (tb[i]) {
 640                         timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
 641                 }
 642         }
 643         return 0;
 644 }
 645
 646 static int
 647 sctp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 648 {
 649         const unsigned int *timeouts = data;
 650         int i;
 651
 652         for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
 653                 if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
 654                         goto nla_put_failure;
 655         }
 656         return 0;
 657
 658 nla_put_failure:
 659         return -ENOSPC;
 660 }
 661
 662 static const struct nla_policy
 663 sctp_timeout_nla_policy[CTA_TIMEOUT_SCTP_MAX+1] = {
 664         [CTA_TIMEOUT_SCTP_CLOSED]               = { .type = NLA_U32 },
 665         [CTA_TIMEOUT_SCTP_COOKIE_WAIT]          = { .type = NLA_U32 },
 666         [CTA_TIMEOUT_SCTP_COOKIE_ECHOED]        = { .type = NLA_U32 },
 667         [CTA_TIMEOUT_SCTP_ESTABLISHED]          = { .type = NLA_U32 },
 668         [CTA_TIMEOUT_SCTP_SHUTDOWN_SENT]        = { .type = NLA_U32 },
 669         [CTA_TIMEOUT_SCTP_SHUTDOWN_RECD]        = { .type = NLA_U32 },
 670         [CTA_TIMEOUT_SCTP_SHUTDOWN_ACK_SENT]    = { .type = NLA_U32 },
 671         [CTA_TIMEOUT_SCTP_HEARTBEAT_SENT]       = { .type = NLA_U32 },
 672         [CTA_TIMEOUT_SCTP_HEARTBEAT_ACKED]      = { .type = NLA_U32 },
 673 };
 674 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 675
 676
 677 #ifdef CONFIG_SYSCTL
 678 static struct ctl_table sctp_sysctl_table[] = {
 679         {
 680                 .procname       = "nf_conntrack_sctp_timeout_closed",
 681                 .maxlen         = sizeof(unsigned int),
 682                 .mode           = 0644,
 683                 .proc_handler   = proc_dointvec_jiffies,
 684         },
 685         {
 686                 .procname       = "nf_conntrack_sctp_timeout_cookie_wait",
 687                 .maxlen         = sizeof(unsigned int),
 688                 .mode           = 0644,
 689                 .proc_handler   = proc_dointvec_jiffies,
 690         },
 691         {
 692                 .procname       = "nf_conntrack_sctp_timeout_cookie_echoed",
 693                 .maxlen         = sizeof(unsigned int),
 694                 .mode           = 0644,
 695                 .proc_handler   = proc_dointvec_jiffies,
 696         },
 697         {
 698                 .procname       = "nf_conntrack_sctp_timeout_established",
 699                 .maxlen         = sizeof(unsigned int),
 700                 .mode           = 0644,
 701                 .proc_handler   = proc_dointvec_jiffies,
 702         },
 703         {
 704                 .procname       = "nf_conntrack_sctp_timeout_shutdown_sent",
 705                 .maxlen         = sizeof(unsigned int),
 706                 .mode           = 0644,
 707                 .proc_handler   = proc_dointvec_jiffies,
 708         },
 709         {
 710                 .procname       = "nf_conntrack_sctp_timeout_shutdown_recd",
 711                 .maxlen         = sizeof(unsigned int),
 712                 .mode           = 0644,
 713                 .proc_handler   = proc_dointvec_jiffies,
 714         },
 715         {
 716                 .procname       = "nf_conntrack_sctp_timeout_shutdown_ack_sent",
 717                 .maxlen         = sizeof(unsigned int),
 718                 .mode           = 0644,
 719                 .proc_handler   = proc_dointvec_jiffies,
 720         },
 721         {
 722                 .procname       = "nf_conntrack_sctp_timeout_heartbeat_sent",
 723                 .maxlen         = sizeof(unsigned int),
 724                 .mode           = 0644,
 725                 .proc_handler   = proc_dointvec_jiffies,
 726         },
 727         {
 728                 .procname       = "nf_conntrack_sctp_timeout_heartbeat_acked",
 729                 .maxlen         = sizeof(unsigned int),
 730                 .mode           = 0644,
 731                 .proc_handler   = proc_dointvec_jiffies,
 732         },
 733         { }
 734 };
 735 #endif
 736
 737 static int sctp_kmemdup_sysctl_table(struct nf_proto_net *pn,
 738                                      struct nf_sctp_net *sn)
 739 {
 740 #ifdef CONFIG_SYSCTL
 741         if (pn->ctl_table)
 742                 return 0;
 743
 744         pn->ctl_table = kmemdup(sctp_sysctl_table,
 745                                 sizeof(sctp_sysctl_table),
 746                                 GFP_KERNEL);
 747         if (!pn->ctl_table)
 748                 return -ENOMEM;
 749
 750         pn->ctl_table[0].data = &sn->timeouts[SCTP_CONNTRACK_CLOSED];
 751         pn->ctl_table[1].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_WAIT];
 752         pn->ctl_table[2].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_ECHOED];
 753         pn->ctl_table[3].data = &sn->timeouts[SCTP_CONNTRACK_ESTABLISHED];
 754         pn->ctl_table[4].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_SENT];
 755         pn->ctl_table[5].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_RECD];
 756         pn->ctl_table[6].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_ACK_SENT];
 757         pn->ctl_table[7].data = &sn->timeouts[SCTP_CONNTRACK_HEARTBEAT_SENT];
 758         pn->ctl_table[8].data = &sn->timeouts[SCTP_CONNTRACK_HEARTBEAT_ACKED];
 759 #endif
 760         return 0;
 761 }
 762
 763 static int sctp_init_net(struct net *net, u_int16_t proto)
 764 {
 765         struct nf_sctp_net *sn = sctp_pernet(net);
 766         struct nf_proto_net *pn = &sn->pn;
 767
 768         if (!pn->users) {
 769                 int i;
 770
 771                 for (i = 0; i < SCTP_CONNTRACK_MAX; i++)
 772                         sn->timeouts[i] = sctp_timeouts[i];
 773         }
 774
 775         return sctp_kmemdup_sysctl_table(pn, sn);
 776 }
 777
 778 static struct nf_proto_net *sctp_get_net_proto(struct net *net)
 779 {
 780         return &net->ct.nf_ct_proto.sctp.pn;
 781 }
 782
 783 struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp4 __read_mostly = {
 784         .l3proto                = PF_INET,
 785         .l4proto                = IPPROTO_SCTP,
 786         .pkt_to_tuple           = sctp_pkt_to_tuple,
 787         .invert_tuple           = sctp_invert_tuple,
 788 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 789         .print_conntrack        = sctp_print_conntrack,
 790 #endif
 791         .packet                 = sctp_packet,
 792         .get_timeouts           = sctp_get_timeouts,
 793         .new                    = sctp_new,
 794         .error                  = sctp_error,
 795         .can_early_drop         = sctp_can_early_drop,
 796         .me                     = THIS_MODULE,
 797 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 798         .to_nlattr              = sctp_to_nlattr,
 799         .nlattr_size            = sctp_nlattr_size,
 800         .from_nlattr            = nlattr_to_sctp,
 801         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 802         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 803         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 804         .nla_policy             = nf_ct_port_nla_policy,
 805 #endif
 806 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 807         .ctnl_timeout           = {
 808                 .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
 809                 .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
 810                 .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
 811                 .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
 812                 .nla_policy     = sctp_timeout_nla_policy,
 813         },
 814 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 815         .init_net               = sctp_init_net,
 816         .get_net_proto          = sctp_get_net_proto,
 817 };
 818 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_sctp4);
 819
 820 struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp6 __read_mostly = {
 821         .l3proto                = PF_INET6,
 822         .l4proto                = IPPROTO_SCTP,
 823         .pkt_to_tuple           = sctp_pkt_to_tuple,
 824         .invert_tuple           = sctp_invert_tuple,
 825 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 826         .print_conntrack        = sctp_print_conntrack,
 827 #endif
 828         .packet                 = sctp_packet,
 829         .get_timeouts           = sctp_get_timeouts,
 830         .new                    = sctp_new,
 831         .error                  = sctp_error,
 832         .can_early_drop         = sctp_can_early_drop,
 833         .me                     = THIS_MODULE,
 834 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 835         .to_nlattr              = sctp_to_nlattr,
 836         .nlattr_size            = sctp_nlattr_size,
 837         .from_nlattr            = nlattr_to_sctp,
 838         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 839         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 840         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 841         .nla_policy             = nf_ct_port_nla_policy,
 842 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 843         .ctnl_timeout           = {
 844                 .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
 845                 .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
 846                 .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
 847                 .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
 848                 .nla_policy     = sctp_timeout_nla_policy,
 849         },
 850 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 851 #endif
 852         .init_net               = sctp_init_net,
 853         .get_net_proto          = sctp_get_net_proto,
 854 };
 855 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_sctp6);