| 1 | /* site.c - manage communication with a remote network site */ |
| 2 | |
| 3 | /* |
| 4 | * This file is part of secnet. |
| 5 | * See README for full list of copyright holders. |
| 6 | * |
| 7 | * secnet is free software; you can redistribute it and/or modify it |
| 8 | * under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version d of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * secnet is distributed in the hope that it will be useful, but |
| 13 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | * General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * version 3 along with secnet; if not, see |
| 19 | * https://www.gnu.org/licenses/gpl.html. |
| 20 | */ |
| 21 | |
| 22 | /* The 'site' code doesn't know anything about the structure of the |
| 23 | packets it's transmitting. In fact, under the new netlink |
| 24 | configuration scheme it doesn't need to know anything at all about |
| 25 | IP addresses, except how to contact its peer. This means it could |
| 26 | potentially be used to tunnel other protocols too (IPv6, IPX, plain |
| 27 | old Ethernet frames) if appropriate netlink code can be written |
| 28 | (and that ought not to be too hard, eg. using the TUN/TAP device to |
| 29 | pretend to be an Ethernet interface). */ |
| 30 | |
| 31 | /* At some point in the future the netlink code will be asked for |
| 32 | configuration information to go in the PING/PONG packets at the end |
| 33 | of the key exchange. */ |
| 34 | |
| 35 | #include "secnet.h" |
| 36 | #include <stdio.h> |
| 37 | #include <string.h> |
| 38 | #include <limits.h> |
| 39 | #include <assert.h> |
| 40 | #include <sys/socket.h> |
| 41 | |
| 42 | #include <sys/mman.h> |
| 43 | #include "util.h" |
| 44 | #include "unaligned.h" |
| 45 | #include "magic.h" |
| 46 | |
| 47 | #define SETUP_BUFFER_LEN 2048 |
| 48 | |
| 49 | #define DEFAULT_KEY_LIFETIME (3600*1000) /* [ms] */ |
| 50 | #define DEFAULT_KEY_RENEGOTIATE_GAP (5*60*1000) /* [ms] */ |
| 51 | #define DEFAULT_SETUP_RETRIES 5 |
| 52 | #define DEFAULT_SETUP_RETRY_INTERVAL (2*1000) /* [ms] */ |
| 53 | #define DEFAULT_WAIT_TIME (20*1000) /* [ms] */ |
| 54 | |
| 55 | #define DEFAULT_MOBILE_KEY_LIFETIME (2*24*3600*1000) /* [ms] */ |
| 56 | #define DEFAULT_MOBILE_KEY_RENEGOTIATE_GAP (12*3600*1000) /* [ms] */ |
| 57 | #define DEFAULT_MOBILE_SETUP_RETRIES 30 |
| 58 | #define DEFAULT_MOBILE_SETUP_RETRY_INTERVAL (1*1000) /* [ms] */ |
| 59 | #define DEFAULT_MOBILE_WAIT_TIME (10*1000) /* [ms] */ |
| 60 | |
| 61 | #define DEFAULT_MOBILE_PEER_EXPIRY (2*60) /* [s] */ |
| 62 | |
| 63 | /* Each site can be in one of several possible states. */ |
| 64 | |
| 65 | /* States: |
| 66 | SITE_STOP - nothing is allowed to happen; tunnel is down; |
| 67 | all session keys have been erased |
| 68 | -> SITE_RUN upon external instruction |
| 69 | SITE_RUN - site up, maybe with valid key |
| 70 | -> SITE_RESOLVE upon outgoing packet and no valid key |
| 71 | we start name resolution for the other end of the tunnel |
| 72 | -> SITE_SENTMSG2 upon valid incoming message 1 and suitable time |
| 73 | we send an appropriate message 2 |
| 74 | SITE_RESOLVE - waiting for name resolution |
| 75 | -> SITE_SENTMSG1 upon successful resolution |
| 76 | we send an appropriate message 1 |
| 77 | -> SITE_SENTMSG2 upon valid incoming message 1 (then abort resolution) |
| 78 | we abort resolution and |
| 79 | -> SITE_WAIT on timeout or resolution failure |
| 80 | SITE_SENTMSG1 |
| 81 | -> SITE_SENTMSG2 upon valid incoming message 1 from higher priority end |
| 82 | -> SITE_SENTMSG3 upon valid incoming message 2 |
| 83 | -> SITE_WAIT on timeout |
| 84 | SITE_SENTMSG2 |
| 85 | -> SITE_SENTMSG4 upon valid incoming message 3 |
| 86 | -> SITE_WAIT on timeout |
| 87 | SITE_SENTMSG3 |
| 88 | -> SITE_SENTMSG5 upon valid incoming message 4 |
| 89 | -> SITE_WAIT on timeout |
| 90 | SITE_SENTMSG4 |
| 91 | -> SITE_RUN upon valid incoming message 5 |
| 92 | -> SITE_WAIT on timeout |
| 93 | SITE_SENTMSG5 |
| 94 | -> SITE_RUN upon valid incoming message 6 |
| 95 | -> SITE_WAIT on timeout |
| 96 | SITE_WAIT - failed to establish key; do nothing for a while |
| 97 | -> SITE_RUN on timeout |
| 98 | */ |
| 99 | |
| 100 | #define SITE_STOP 0 |
| 101 | #define SITE_RUN 1 |
| 102 | #define SITE_RESOLVE 2 |
| 103 | #define SITE_SENTMSG1 3 |
| 104 | #define SITE_SENTMSG2 4 |
| 105 | #define SITE_SENTMSG3 5 |
| 106 | #define SITE_SENTMSG4 6 |
| 107 | #define SITE_SENTMSG5 7 |
| 108 | #define SITE_WAIT 8 |
| 109 | |
| 110 | int32_t site_max_start_pad = 4*4; |
| 111 | |
| 112 | static cstring_t state_name(uint32_t state) |
| 113 | { |
| 114 | switch (state) { |
| 115 | case 0: return "STOP"; |
| 116 | case 1: return "RUN"; |
| 117 | case 2: return "RESOLVE"; |
| 118 | case 3: return "SENTMSG1"; |
| 119 | case 4: return "SENTMSG2"; |
| 120 | case 5: return "SENTMSG3"; |
| 121 | case 6: return "SENTMSG4"; |
| 122 | case 7: return "SENTMSG5"; |
| 123 | case 8: return "WAIT"; |
| 124 | default: return "*bad state*"; |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | #define NONCELEN 8 |
| 129 | |
| 130 | #define LOG_UNEXPECTED 0x00000001 |
| 131 | #define LOG_SETUP_INIT 0x00000002 |
| 132 | #define LOG_SETUP_TIMEOUT 0x00000004 |
| 133 | #define LOG_ACTIVATE_KEY 0x00000008 |
| 134 | #define LOG_TIMEOUT_KEY 0x00000010 |
| 135 | #define LOG_SEC 0x00000020 |
| 136 | #define LOG_STATE 0x00000040 |
| 137 | #define LOG_DROP 0x00000080 |
| 138 | #define LOG_DUMP 0x00000100 |
| 139 | #define LOG_ERROR 0x00000400 |
| 140 | #define LOG_PEER_ADDRS 0x00000800 |
| 141 | |
| 142 | static struct flagstr log_event_table[]={ |
| 143 | { "unexpected", LOG_UNEXPECTED }, |
| 144 | { "setup-init", LOG_SETUP_INIT }, |
| 145 | { "setup-timeout", LOG_SETUP_TIMEOUT }, |
| 146 | { "activate-key", LOG_ACTIVATE_KEY }, |
| 147 | { "timeout-key", LOG_TIMEOUT_KEY }, |
| 148 | { "security", LOG_SEC }, |
| 149 | { "state-change", LOG_STATE }, |
| 150 | { "packet-drop", LOG_DROP }, |
| 151 | { "dump-packets", LOG_DUMP }, |
| 152 | { "errors", LOG_ERROR }, |
| 153 | { "peer-addrs", LOG_PEER_ADDRS }, |
| 154 | { "default", LOG_SETUP_INIT|LOG_SETUP_TIMEOUT| |
| 155 | LOG_ACTIVATE_KEY|LOG_TIMEOUT_KEY|LOG_SEC|LOG_ERROR }, |
| 156 | { "all", 0xffffffff }, |
| 157 | { NULL, 0 } |
| 158 | }; |
| 159 | |
| 160 | |
| 161 | /***** TRANSPORT PEERS declarations *****/ |
| 162 | |
| 163 | /* Details of "mobile peer" semantics: |
| 164 | |
| 165 | - We use the same data structure for the different configurations, |
| 166 | but manage it with different algorithms. |
| 167 | |
| 168 | - We record up to mobile_peers_max peer address/port numbers |
| 169 | ("peers") for key setup, and separately up to mobile_peers_max |
| 170 | for data transfer. |
| 171 | |
| 172 | - In general, we make a new set of addrs (see below) when we start |
| 173 | a new key exchange; the key setup addrs become the data transport |
| 174 | addrs when key setup complets. |
| 175 | |
| 176 | If our peer is mobile: |
| 177 | |
| 178 | - We send to all recent addresses of incoming packets, plus |
| 179 | initially all configured addresses (which we also expire). |
| 180 | |
| 181 | - So, we record addrs of good incoming packets, as follows: |
| 182 | 1. expire any peers last seen >120s ("mobile-peer-expiry") ago |
| 183 | 2. add the peer of the just received packet to the applicable list |
| 184 | (possibly evicting the oldest entries to make room) |
| 185 | NB that we do not expire peers until an incoming packet arrives. |
| 186 | |
| 187 | - If the peer has a configured address or name, we record them the |
| 188 | same way, but only as a result of our own initiation of key |
| 189 | setup. (We might evict some incoming packet addrs to make room.) |
| 190 | |
| 191 | - The default number of addrs to keep is 3, or 4 if we have a |
| 192 | configured name or address. That's space for two configured |
| 193 | addresses (one IPv6 and one IPv4), plus two received addresses. |
| 194 | |
| 195 | - Outgoing packets are sent to every recorded address in the |
| 196 | applicable list. Any unsupported[1] addresses are deleted from |
| 197 | the list right away. (This should only happen to configured |
| 198 | addresses, of course, but there is no need to check that.) |
| 199 | |
| 200 | - When we successfully complete a key setup, we merge the key setup |
| 201 | peers into the data transfer peers. |
| 202 | |
| 203 | [1] An unsupported address is one for whose AF we don't have a |
| 204 | socket (perhaps because we got EAFNOSUPPORT or some such) or for |
| 205 | which sendto gives ENETUNREACH. |
| 206 | |
| 207 | If neither end is mobile: |
| 208 | |
| 209 | - When peer initiated the key exchange, we use the incoming packet |
| 210 | address. |
| 211 | |
| 212 | - When we initiate the key exchange, we try configured addresses |
| 213 | until we get one which isn't unsupported then fixate on that. |
| 214 | |
| 215 | - When we complete a key setup, we replace the data transport peers |
| 216 | with those from the key setup. |
| 217 | |
| 218 | If we are mobile: |
| 219 | |
| 220 | - We can't tell when local network setup changes so we can't cache |
| 221 | the unsupported addrs and completely remove the spurious calls to |
| 222 | sendto, but we can optimise things a bit by deprioritising addrs |
| 223 | which seem to be unsupported. |
| 224 | |
| 225 | - Use only configured addresses. (Except, that if our peer |
| 226 | initiated a key exchange we use the incoming packet address until |
| 227 | our name resolution completes.) |
| 228 | |
| 229 | - When we send a packet, try each address in turn; if addr |
| 230 | supported, put that address to the end of the list for future |
| 231 | packets, and go onto the next address. |
| 232 | |
| 233 | - When we complete a key setup, we replace the data transport peers |
| 234 | with those from the key setup. |
| 235 | |
| 236 | */ |
| 237 | |
| 238 | typedef struct { |
| 239 | struct timeval last; |
| 240 | struct comm_addr addr; |
| 241 | } transport_peer; |
| 242 | |
| 243 | typedef struct { |
| 244 | /* configuration information */ |
| 245 | /* runtime information */ |
| 246 | int npeers; |
| 247 | transport_peer peers[MAX_PEER_ADDRS]; |
| 248 | } transport_peers; |
| 249 | |
| 250 | /* Basic operations on transport peer address sets */ |
| 251 | static void transport_peers_clear(struct site *st, transport_peers *peers); |
| 252 | static int transport_peers_valid(transport_peers *peers); |
| 253 | static void transport_peers_copy(struct site *st, transport_peers *dst, |
| 254 | const transport_peers *src); |
| 255 | |
| 256 | /* Record address of incoming setup packet; resp. data packet. */ |
| 257 | static void transport_setup_msgok(struct site *st, const struct comm_addr *a); |
| 258 | static void transport_data_msgok(struct site *st, const struct comm_addr *a); |
| 259 | |
| 260 | /* Initialise the setup addresses. Called before we send the first |
| 261 | * packet in a key exchange. If we are the initiator, as a result of |
| 262 | * resolve completing (or being determined not to be relevant) or an |
| 263 | * incoming PROD; if we are the responder, as a result of the MSG1. */ |
| 264 | static bool_t transport_compute_setupinit_peers(struct site *st, |
| 265 | const struct comm_addr *configured_addrs /* 0 if none or not found */, |
| 266 | int n_configured_addrs /* 0 if none or not found */, |
| 267 | const struct comm_addr *incoming_packet_addr /* 0 if none */); |
| 268 | |
| 269 | /* Called if we are the responder in a key setup, when the resolve |
| 270 | * completes. transport_compute_setupinit_peers will hvae been called |
| 271 | * earlier. If _complete is called, we are still doing the key setup |
| 272 | * (and we should use the new values for both the rest of the key |
| 273 | * setup and the ongoing data exchange); if _tardy is called, the key |
| 274 | * setup is done (either completed or not) and only the data peers are |
| 275 | * relevant */ |
| 276 | static void transport_resolve_complete(struct site *st, |
| 277 | const struct comm_addr *addrs, int naddrs); |
| 278 | static void transport_resolve_complete_tardy(struct site *st, |
| 279 | const struct comm_addr *addrs, int naddrs); |
| 280 | |
| 281 | static void transport_xmit(struct site *st, transport_peers *peers, |
| 282 | struct buffer_if *buf, bool_t candebug); |
| 283 | |
| 284 | /***** END of transport peers declarations *****/ |
| 285 | |
| 286 | |
| 287 | struct data_key { |
| 288 | struct transform_inst_if *transform; |
| 289 | uint64_t key_timeout; /* End of life of current key */ |
| 290 | uint32_t remote_session_id; |
| 291 | }; |
| 292 | |
| 293 | struct site { |
| 294 | closure_t cl; |
| 295 | struct site_if ops; |
| 296 | /* configuration information */ |
| 297 | string_t localname; |
| 298 | string_t remotename; |
| 299 | bool_t keepalive; |
| 300 | bool_t local_mobile, peer_mobile; /* Mobile client support */ |
| 301 | int32_t transport_peers_max; |
| 302 | string_t tunname; /* localname<->remotename by default, used in logs */ |
| 303 | cstring_t *addresses; /* DNS name or address(es) for bootstrapping, optional */ |
| 304 | int remoteport; /* Port for bootstrapping, optional */ |
| 305 | uint32_t mtu_target; |
| 306 | struct netlink_if *netlink; |
| 307 | struct comm_if **comms; |
| 308 | struct comm_clientinfo **commclientinfos; |
| 309 | int ncomms; |
| 310 | struct resolver_if *resolver; |
| 311 | struct log_if *log; |
| 312 | struct random_if *random; |
| 313 | struct rsaprivkey_if *privkey; |
| 314 | struct rsapubkey_if *pubkey; |
| 315 | struct transform_if **transforms; |
| 316 | int ntransforms; |
| 317 | struct dh_if *dh; |
| 318 | struct hash_if *hash; |
| 319 | |
| 320 | uint32_t index; /* Index of this site */ |
| 321 | uint32_t local_capabilities; |
| 322 | int32_t setup_retries; /* How many times to send setup packets */ |
| 323 | int32_t setup_retry_interval; /* Initial timeout for setup packets */ |
| 324 | int32_t wait_timeout; /* How long to wait if setup unsuccessful */ |
| 325 | int32_t mobile_peer_expiry; /* How long to remember 2ary addresses */ |
| 326 | int32_t key_lifetime; /* How long a key lasts once set up */ |
| 327 | int32_t key_renegotiate_time; /* If we see traffic (or a keepalive) |
| 328 | after this time, initiate a new |
| 329 | key exchange */ |
| 330 | |
| 331 | bool_t setup_priority; /* Do we have precedence if both sites emit |
| 332 | message 1 simultaneously? */ |
| 333 | uint32_t log_events; |
| 334 | |
| 335 | /* runtime information */ |
| 336 | uint32_t state; |
| 337 | uint64_t now; /* Most recently seen time */ |
| 338 | bool_t allow_send_prod; |
| 339 | int resolving_count; |
| 340 | int resolving_n_results_all; |
| 341 | int resolving_n_results_stored; |
| 342 | struct comm_addr resolving_results[MAX_PEER_ADDRS]; |
| 343 | |
| 344 | /* The currently established session */ |
| 345 | struct data_key current; |
| 346 | struct data_key auxiliary_key; |
| 347 | bool_t auxiliary_is_new; |
| 348 | uint64_t renegotiate_key_time; /* When we can negotiate a new key */ |
| 349 | uint64_t auxiliary_renegotiate_key_time; |
| 350 | transport_peers peers; /* Current address(es) of peer for data traffic */ |
| 351 | |
| 352 | /* The current key setup protocol exchange. We can only be |
| 353 | involved in one of these at a time. There's a potential for |
| 354 | denial of service here (the attacker keeps sending a setup |
| 355 | packet; we keep trying to continue the exchange, and have to |
| 356 | timeout before we can listen for another setup packet); perhaps |
| 357 | we should keep a list of 'bad' sources for setup packets. */ |
| 358 | uint32_t remote_capabilities; |
| 359 | uint16_t remote_adv_mtu; |
| 360 | struct transform_if *chosen_transform; |
| 361 | uint32_t setup_session_id; |
| 362 | transport_peers setup_peers; |
| 363 | uint8_t localN[NONCELEN]; /* Nonces for key exchange */ |
| 364 | uint8_t remoteN[NONCELEN]; |
| 365 | struct buffer_if buffer; /* Current outgoing key exchange packet */ |
| 366 | struct buffer_if scratch; |
| 367 | int32_t retries; /* Number of retries remaining */ |
| 368 | uint64_t timeout; /* Timeout for current state */ |
| 369 | uint8_t *dhsecret; |
| 370 | uint8_t *sharedsecret; |
| 371 | uint32_t sharedsecretlen, sharedsecretallocd; |
| 372 | struct transform_inst_if *new_transform; /* For key setup/verify */ |
| 373 | }; |
| 374 | |
| 375 | static uint32_t event_log_priority(struct site *st, uint32_t event) |
| 376 | { |
| 377 | if (!(event&st->log_events)) |
| 378 | return 0; |
| 379 | switch(event) { |
| 380 | case LOG_UNEXPECTED: return M_INFO; |
| 381 | case LOG_SETUP_INIT: return M_INFO; |
| 382 | case LOG_SETUP_TIMEOUT: return M_NOTICE; |
| 383 | case LOG_ACTIVATE_KEY: return M_INFO; |
| 384 | case LOG_TIMEOUT_KEY: return M_INFO; |
| 385 | case LOG_SEC: return M_SECURITY; |
| 386 | case LOG_STATE: return M_DEBUG; |
| 387 | case LOG_DROP: return M_DEBUG; |
| 388 | case LOG_DUMP: return M_DEBUG; |
| 389 | case LOG_ERROR: return M_ERR; |
| 390 | case LOG_PEER_ADDRS: return M_DEBUG; |
| 391 | default: return M_ERR; |
| 392 | } |
| 393 | } |
| 394 | |
| 395 | static void vslog(struct site *st, uint32_t event, cstring_t msg, va_list ap) |
| 396 | FORMAT(printf,3,0); |
| 397 | static void vslog(struct site *st, uint32_t event, cstring_t msg, va_list ap) |
| 398 | { |
| 399 | uint32_t class; |
| 400 | |
| 401 | class=event_log_priority(st, event); |
| 402 | if (class) { |
| 403 | slilog_part(st->log,class,"%s: ",st->tunname); |
| 404 | vslilog_part(st->log,class,msg,ap); |
| 405 | slilog_part(st->log,class,"\n"); |
| 406 | } |
| 407 | } |
| 408 | |
| 409 | static void slog(struct site *st, uint32_t event, cstring_t msg, ...) |
| 410 | FORMAT(printf,3,4); |
| 411 | static void slog(struct site *st, uint32_t event, cstring_t msg, ...) |
| 412 | { |
| 413 | va_list ap; |
| 414 | va_start(ap,msg); |
| 415 | vslog(st,event,msg,ap); |
| 416 | va_end(ap); |
| 417 | } |
| 418 | |
| 419 | static void logtimeout(struct site *st, const char *fmt, ...) |
| 420 | FORMAT(printf,2,3); |
| 421 | static void logtimeout(struct site *st, const char *fmt, ...) |
| 422 | { |
| 423 | uint32_t class=event_log_priority(st,LOG_SETUP_TIMEOUT); |
| 424 | if (!class) |
| 425 | return; |
| 426 | |
| 427 | va_list ap; |
| 428 | va_start(ap,fmt); |
| 429 | |
| 430 | slilog_part(st->log,class,"%s: ",st->tunname); |
| 431 | vslilog_part(st->log,class,fmt,ap); |
| 432 | |
| 433 | const char *delim; |
| 434 | int i; |
| 435 | for (i=0, delim=" (tried "; |
| 436 | i<st->setup_peers.npeers; |
| 437 | i++, delim=", ") { |
| 438 | transport_peer *peer=&st->setup_peers.peers[i]; |
| 439 | const char *s=comm_addr_to_string(&peer->addr); |
| 440 | slilog_part(st->log,class,"%s%s",delim,s); |
| 441 | } |
| 442 | |
| 443 | slilog_part(st->log,class,")\n"); |
| 444 | va_end(ap); |
| 445 | } |
| 446 | |
| 447 | static void set_link_quality(struct site *st); |
| 448 | static void delete_keys(struct site *st, cstring_t reason, uint32_t loglevel); |
| 449 | static void delete_one_key(struct site *st, struct data_key *key, |
| 450 | const char *reason /* may be 0 meaning don't log*/, |
| 451 | const char *which /* ignored if !reasonn */, |
| 452 | uint32_t loglevel /* ignored if !reasonn */); |
| 453 | static bool_t initiate_key_setup(struct site *st, cstring_t reason, |
| 454 | const struct comm_addr *prod_hint); |
| 455 | static void enter_state_run(struct site *st); |
| 456 | static bool_t enter_state_resolve(struct site *st); |
| 457 | static void decrement_resolving_count(struct site *st, int by); |
| 458 | static bool_t enter_new_state(struct site *st,uint32_t next); |
| 459 | static void enter_state_wait(struct site *st); |
| 460 | static void activate_new_key(struct site *st); |
| 461 | |
| 462 | static bool_t is_transform_valid(struct transform_inst_if *transform) |
| 463 | { |
| 464 | return transform && transform->valid(transform->st); |
| 465 | } |
| 466 | |
| 467 | static bool_t current_valid(struct site *st) |
| 468 | { |
| 469 | return is_transform_valid(st->current.transform); |
| 470 | } |
| 471 | |
| 472 | #define DEFINE_CALL_TRANSFORM(fwdrev) \ |
| 473 | static int call_transform_##fwdrev(struct site *st, \ |
| 474 | struct transform_inst_if *transform, \ |
| 475 | struct buffer_if *buf, \ |
| 476 | const char **errmsg) \ |
| 477 | { \ |
| 478 | if (!is_transform_valid(transform)) { \ |
| 479 | *errmsg="transform not set up"; \ |
| 480 | return 1; \ |
| 481 | } \ |
| 482 | return transform->fwdrev(transform->st,buf,errmsg); \ |
| 483 | } |
| 484 | |
| 485 | DEFINE_CALL_TRANSFORM(forwards) |
| 486 | DEFINE_CALL_TRANSFORM(reverse) |
| 487 | |
| 488 | static void dispose_transform(struct transform_inst_if **transform_var) |
| 489 | { |
| 490 | struct transform_inst_if *transform=*transform_var; |
| 491 | if (transform) { |
| 492 | transform->delkey(transform->st); |
| 493 | transform->destroy(transform->st); |
| 494 | } |
| 495 | *transform_var = 0; |
| 496 | } |
| 497 | |
| 498 | #define CHECK_AVAIL(b,l) do { if ((b)->size<(l)) return False; } while(0) |
| 499 | #define CHECK_EMPTY(b) do { if ((b)->size!=0) return False; } while(0) |
| 500 | #define CHECK_TYPE(b,t) do { uint32_t type; \ |
| 501 | CHECK_AVAIL((b),4); \ |
| 502 | type=buf_unprepend_uint32((b)); \ |
| 503 | if (type!=(t)) return False; } while(0) |
| 504 | |
| 505 | static _Bool type_is_msg34(uint32_t type) |
| 506 | { |
| 507 | return |
| 508 | type == LABEL_MSG3 || |
| 509 | type == LABEL_MSG3BIS || |
| 510 | type == LABEL_MSG4; |
| 511 | } |
| 512 | |
| 513 | struct parsedname { |
| 514 | int32_t len; |
| 515 | uint8_t *name; |
| 516 | struct buffer_if extrainfo; |
| 517 | }; |
| 518 | |
| 519 | struct msg { |
| 520 | uint8_t *hashstart; |
| 521 | uint32_t dest; |
| 522 | uint32_t source; |
| 523 | struct parsedname remote; |
| 524 | struct parsedname local; |
| 525 | uint32_t remote_capabilities; |
| 526 | uint16_t remote_mtu; |
| 527 | int capab_transformnum; |
| 528 | uint8_t *nR; |
| 529 | uint8_t *nL; |
| 530 | int32_t pklen; |
| 531 | char *pk; |
| 532 | int32_t hashlen; |
| 533 | int32_t siglen; |
| 534 | char *sig; |
| 535 | }; |
| 536 | |
| 537 | static void set_new_transform(struct site *st, char *pk) |
| 538 | { |
| 539 | /* Make room for the shared key */ |
| 540 | st->sharedsecretlen=st->chosen_transform->keylen?:st->dh->ceil_len; |
| 541 | assert(st->sharedsecretlen); |
| 542 | if (st->sharedsecretlen > st->sharedsecretallocd) { |
| 543 | st->sharedsecretallocd=st->sharedsecretlen; |
| 544 | st->sharedsecret=safe_realloc_ary(st->sharedsecret,1, |
| 545 | st->sharedsecretallocd, |
| 546 | "site:sharedsecret"); |
| 547 | } |
| 548 | |
| 549 | /* Generate the shared key */ |
| 550 | st->dh->makeshared(st->dh->st,st->dhsecret,st->dh->len,pk, |
| 551 | st->sharedsecret,st->sharedsecretlen); |
| 552 | |
| 553 | /* Set up the transform */ |
| 554 | struct transform_if *generator=st->chosen_transform; |
| 555 | struct transform_inst_if *generated=generator->create(generator->st); |
| 556 | generated->setkey(generated->st,st->sharedsecret, |
| 557 | st->sharedsecretlen,st->setup_priority); |
| 558 | dispose_transform(&st->new_transform); |
| 559 | st->new_transform=generated; |
| 560 | |
| 561 | slog(st,LOG_SETUP_INIT,"key exchange negotiated transform" |
| 562 | " %d (capabilities ours=%#"PRIx32" theirs=%#"PRIx32")", |
| 563 | st->chosen_transform->capab_transformnum, |
| 564 | st->local_capabilities, st->remote_capabilities); |
| 565 | } |
| 566 | |
| 567 | struct xinfoadd { |
| 568 | int32_t lenpos, afternul; |
| 569 | }; |
| 570 | static void append_string_xinfo_start(struct buffer_if *buf, |
| 571 | struct xinfoadd *xia, |
| 572 | const char *str) |
| 573 | /* Helps construct one of the names with additional info as found |
| 574 | * in MSG1..4. Call this function first, then append all the |
| 575 | * desired extra info (not including the nul byte) to the buffer, |
| 576 | * then call append_string_xinfo_done. */ |
| 577 | { |
| 578 | xia->lenpos = buf->size; |
| 579 | buf_append_string(buf,str); |
| 580 | buf_append_uint8(buf,0); |
| 581 | xia->afternul = buf->size; |
| 582 | } |
| 583 | static void append_string_xinfo_done(struct buffer_if *buf, |
| 584 | struct xinfoadd *xia) |
| 585 | { |
| 586 | /* we just need to adjust the string length */ |
| 587 | if (buf->size == xia->afternul) { |
| 588 | /* no extra info, strip the nul too */ |
| 589 | buf_unappend_uint8(buf); |
| 590 | } else { |
| 591 | put_uint16(buf->start+xia->lenpos, buf->size-(xia->lenpos+2)); |
| 592 | } |
| 593 | } |
| 594 | |
| 595 | /* Build any of msg1 to msg4. msg5 and msg6 are built from the inside |
| 596 | out using a transform of config data supplied by netlink */ |
| 597 | static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what) |
| 598 | { |
| 599 | void *hst; |
| 600 | uint8_t *hash; |
| 601 | string_t dhpub, sig; |
| 602 | |
| 603 | st->retries=st->setup_retries; |
| 604 | BUF_ALLOC(&st->buffer,what); |
| 605 | buffer_init(&st->buffer,0); |
| 606 | buf_append_uint32(&st->buffer, |
| 607 | (type==LABEL_MSG1?0:st->setup_session_id)); |
| 608 | buf_append_uint32(&st->buffer,st->index); |
| 609 | buf_append_uint32(&st->buffer,type); |
| 610 | |
| 611 | struct xinfoadd xia; |
| 612 | append_string_xinfo_start(&st->buffer,&xia,st->localname); |
| 613 | if ((st->local_capabilities & CAPAB_EARLY) || (type != LABEL_MSG1)) { |
| 614 | buf_append_uint32(&st->buffer,st->local_capabilities); |
| 615 | } |
| 616 | if (type_is_msg34(type)) { |
| 617 | buf_append_uint16(&st->buffer,st->mtu_target); |
| 618 | } |
| 619 | append_string_xinfo_done(&st->buffer,&xia); |
| 620 | |
| 621 | buf_append_string(&st->buffer,st->remotename); |
| 622 | BUF_ADD_OBJ(append,&st->buffer,st->localN); |
| 623 | if (type==LABEL_MSG1) return True; |
| 624 | BUF_ADD_OBJ(append,&st->buffer,st->remoteN); |
| 625 | if (type==LABEL_MSG2) return True; |
| 626 | |
| 627 | if (hacky_par_mid_failnow()) return False; |
| 628 | |
| 629 | if (type==LABEL_MSG3BIS) |
| 630 | buf_append_uint8(&st->buffer,st->chosen_transform->capab_transformnum); |
| 631 | |
| 632 | dhpub=st->dh->makepublic(st->dh->st,st->dhsecret,st->dh->len); |
| 633 | buf_append_string(&st->buffer,dhpub); |
| 634 | free(dhpub); |
| 635 | hash=safe_malloc(st->hash->len, "generate_msg"); |
| 636 | hst=st->hash->init(); |
| 637 | st->hash->update(hst,st->buffer.start,st->buffer.size); |
| 638 | st->hash->final(hst,hash); |
| 639 | sig=st->privkey->sign(st->privkey->st,hash,st->hash->len); |
| 640 | buf_append_string(&st->buffer,sig); |
| 641 | free(sig); |
| 642 | free(hash); |
| 643 | return True; |
| 644 | } |
| 645 | |
| 646 | static bool_t unpick_name(struct buffer_if *msg, struct parsedname *nm) |
| 647 | { |
| 648 | CHECK_AVAIL(msg,2); |
| 649 | nm->len=buf_unprepend_uint16(msg); |
| 650 | CHECK_AVAIL(msg,nm->len); |
| 651 | nm->name=buf_unprepend(msg,nm->len); |
| 652 | uint8_t *nul=memchr(nm->name,0,nm->len); |
| 653 | if (!nul) { |
| 654 | buffer_readonly_view(&nm->extrainfo,0,0); |
| 655 | } else { |
| 656 | buffer_readonly_view(&nm->extrainfo, nul+1, msg->start-(nul+1)); |
| 657 | nm->len=nul-nm->name; |
| 658 | } |
| 659 | return True; |
| 660 | } |
| 661 | |
| 662 | static bool_t unpick_msg(struct site *st, uint32_t type, |
| 663 | struct buffer_if *msg, struct msg *m) |
| 664 | { |
| 665 | m->capab_transformnum=-1; |
| 666 | m->hashstart=msg->start; |
| 667 | CHECK_AVAIL(msg,4); |
| 668 | m->dest=buf_unprepend_uint32(msg); |
| 669 | CHECK_AVAIL(msg,4); |
| 670 | m->source=buf_unprepend_uint32(msg); |
| 671 | CHECK_TYPE(msg,type); |
| 672 | if (!unpick_name(msg,&m->remote)) return False; |
| 673 | m->remote_capabilities=0; |
| 674 | m->remote_mtu=0; |
| 675 | if (m->remote.extrainfo.size) { |
| 676 | CHECK_AVAIL(&m->remote.extrainfo,4); |
| 677 | m->remote_capabilities=buf_unprepend_uint32(&m->remote.extrainfo); |
| 678 | } |
| 679 | if (type_is_msg34(type) && m->remote.extrainfo.size) { |
| 680 | CHECK_AVAIL(&m->remote.extrainfo,2); |
| 681 | m->remote_mtu=buf_unprepend_uint16(&m->remote.extrainfo); |
| 682 | } |
| 683 | if (!unpick_name(msg,&m->local)) return False; |
| 684 | if (type==LABEL_PROD) { |
| 685 | CHECK_EMPTY(msg); |
| 686 | return True; |
| 687 | } |
| 688 | CHECK_AVAIL(msg,NONCELEN); |
| 689 | m->nR=buf_unprepend(msg,NONCELEN); |
| 690 | if (type==LABEL_MSG1) { |
| 691 | CHECK_EMPTY(msg); |
| 692 | return True; |
| 693 | } |
| 694 | CHECK_AVAIL(msg,NONCELEN); |
| 695 | m->nL=buf_unprepend(msg,NONCELEN); |
| 696 | if (type==LABEL_MSG2) { |
| 697 | CHECK_EMPTY(msg); |
| 698 | return True; |
| 699 | } |
| 700 | if (type==LABEL_MSG3BIS) { |
| 701 | CHECK_AVAIL(msg,1); |
| 702 | m->capab_transformnum = buf_unprepend_uint8(msg); |
| 703 | } else { |
| 704 | m->capab_transformnum = CAPAB_TRANSFORMNUM_ANCIENT; |
| 705 | } |
| 706 | CHECK_AVAIL(msg,2); |
| 707 | m->pklen=buf_unprepend_uint16(msg); |
| 708 | CHECK_AVAIL(msg,m->pklen); |
| 709 | m->pk=buf_unprepend(msg,m->pklen); |
| 710 | m->hashlen=msg->start-m->hashstart; |
| 711 | CHECK_AVAIL(msg,2); |
| 712 | m->siglen=buf_unprepend_uint16(msg); |
| 713 | CHECK_AVAIL(msg,m->siglen); |
| 714 | m->sig=buf_unprepend(msg,m->siglen); |
| 715 | CHECK_EMPTY(msg); |
| 716 | return True; |
| 717 | } |
| 718 | |
| 719 | static bool_t name_matches(const struct parsedname *nm, const char *expected) |
| 720 | { |
| 721 | int expected_len=strlen(expected); |
| 722 | return |
| 723 | nm->len == expected_len && |
| 724 | !memcmp(nm->name, expected, expected_len); |
| 725 | } |
| 726 | |
| 727 | static bool_t check_msg(struct site *st, uint32_t type, struct msg *m, |
| 728 | cstring_t *error) |
| 729 | { |
| 730 | if (type==LABEL_MSG1) return True; |
| 731 | |
| 732 | /* Check that the site names and our nonce have been sent |
| 733 | back correctly, and then store our peer's nonce. */ |
| 734 | if (!name_matches(&m->remote,st->remotename)) { |
| 735 | *error="wrong remote site name"; |
| 736 | return False; |
| 737 | } |
| 738 | if (!name_matches(&m->local,st->localname)) { |
| 739 | *error="wrong local site name"; |
| 740 | return False; |
| 741 | } |
| 742 | if (memcmp(m->nL,st->localN,NONCELEN)!=0) { |
| 743 | *error="wrong locally-generated nonce"; |
| 744 | return False; |
| 745 | } |
| 746 | if (type==LABEL_MSG2) return True; |
| 747 | if (!consttime_memeq(m->nR,st->remoteN,NONCELEN)!=0) { |
| 748 | *error="wrong remotely-generated nonce"; |
| 749 | return False; |
| 750 | } |
| 751 | /* MSG3 has complicated rules about capabilities, which are |
| 752 | * handled in process_msg3. */ |
| 753 | if (type==LABEL_MSG3 || type==LABEL_MSG3BIS) return True; |
| 754 | if (m->remote_capabilities!=st->remote_capabilities) { |
| 755 | *error="remote capabilities changed"; |
| 756 | return False; |
| 757 | } |
| 758 | if (type==LABEL_MSG4) return True; |
| 759 | *error="unknown message type"; |
| 760 | return False; |
| 761 | } |
| 762 | |
| 763 | static bool_t generate_msg1(struct site *st) |
| 764 | { |
| 765 | st->random->generate(st->random->st,NONCELEN,st->localN); |
| 766 | return generate_msg(st,LABEL_MSG1,"site:MSG1"); |
| 767 | } |
| 768 | |
| 769 | static bool_t process_msg1(struct site *st, struct buffer_if *msg1, |
| 770 | const struct comm_addr *src, struct msg *m) |
| 771 | { |
| 772 | /* We've already determined we're in an appropriate state to |
| 773 | process an incoming MSG1, and that the MSG1 has correct values |
| 774 | of A and B. */ |
| 775 | |
| 776 | st->setup_session_id=m->source; |
| 777 | st->remote_capabilities=m->remote_capabilities; |
| 778 | memcpy(st->remoteN,m->nR,NONCELEN); |
| 779 | return True; |
| 780 | } |
| 781 | |
| 782 | static bool_t generate_msg2(struct site *st) |
| 783 | { |
| 784 | st->random->generate(st->random->st,NONCELEN,st->localN); |
| 785 | return generate_msg(st,LABEL_MSG2,"site:MSG2"); |
| 786 | } |
| 787 | |
| 788 | static bool_t process_msg2(struct site *st, struct buffer_if *msg2, |
| 789 | const struct comm_addr *src) |
| 790 | { |
| 791 | struct msg m; |
| 792 | cstring_t err; |
| 793 | |
| 794 | if (!unpick_msg(st,LABEL_MSG2,msg2,&m)) return False; |
| 795 | if (!check_msg(st,LABEL_MSG2,&m,&err)) { |
| 796 | slog(st,LOG_SEC,"msg2: %s",err); |
| 797 | return False; |
| 798 | } |
| 799 | st->setup_session_id=m.source; |
| 800 | st->remote_capabilities=m.remote_capabilities; |
| 801 | |
| 802 | /* Select the transform to use */ |
| 803 | |
| 804 | uint32_t remote_transforms = st->remote_capabilities & CAPAB_TRANSFORM_MASK; |
| 805 | if (!remote_transforms) |
| 806 | /* old secnets only had this one transform */ |
| 807 | remote_transforms = 1UL << CAPAB_TRANSFORMNUM_ANCIENT; |
| 808 | |
| 809 | struct transform_if *ti; |
| 810 | int i; |
| 811 | for (i=0; i<st->ntransforms; i++) { |
| 812 | ti=st->transforms[i]; |
| 813 | if ((1UL << ti->capab_transformnum) & remote_transforms) |
| 814 | goto transform_found; |
| 815 | } |
| 816 | slog(st,LOG_ERROR,"no transforms in common" |
| 817 | " (us %#"PRIx32"; them: %#"PRIx32")", |
| 818 | st->local_capabilities & CAPAB_TRANSFORM_MASK, |
| 819 | remote_transforms); |
| 820 | return False; |
| 821 | transform_found: |
| 822 | st->chosen_transform=ti; |
| 823 | |
| 824 | memcpy(st->remoteN,m.nR,NONCELEN); |
| 825 | return True; |
| 826 | } |
| 827 | |
| 828 | static bool_t generate_msg3(struct site *st) |
| 829 | { |
| 830 | /* Now we have our nonce and their nonce. Think of a secret key, |
| 831 | and create message number 3. */ |
| 832 | st->random->generate(st->random->st,st->dh->len,st->dhsecret); |
| 833 | return generate_msg(st, |
| 834 | (st->remote_capabilities & CAPAB_TRANSFORM_MASK |
| 835 | ? LABEL_MSG3BIS : LABEL_MSG3), |
| 836 | "site:MSG3"); |
| 837 | } |
| 838 | |
| 839 | static bool_t process_msg3_msg4(struct site *st, struct msg *m) |
| 840 | { |
| 841 | uint8_t *hash; |
| 842 | void *hst; |
| 843 | |
| 844 | /* Check signature and store g^x mod m */ |
| 845 | hash=safe_malloc(st->hash->len, "process_msg3_msg4"); |
| 846 | hst=st->hash->init(); |
| 847 | st->hash->update(hst,m->hashstart,m->hashlen); |
| 848 | st->hash->final(hst,hash); |
| 849 | /* Terminate signature with a '0' - cheating, but should be ok */ |
| 850 | m->sig[m->siglen]=0; |
| 851 | if (!st->pubkey->check(st->pubkey->st,hash,st->hash->len,m->sig)) { |
| 852 | slog(st,LOG_SEC,"msg3/msg4 signature failed check!"); |
| 853 | free(hash); |
| 854 | return False; |
| 855 | } |
| 856 | free(hash); |
| 857 | |
| 858 | st->remote_adv_mtu=m->remote_mtu; |
| 859 | |
| 860 | return True; |
| 861 | } |
| 862 | |
| 863 | static bool_t process_msg3(struct site *st, struct buffer_if *msg3, |
| 864 | const struct comm_addr *src, uint32_t msgtype) |
| 865 | { |
| 866 | struct msg m; |
| 867 | cstring_t err; |
| 868 | |
| 869 | assert(msgtype==LABEL_MSG3 || msgtype==LABEL_MSG3BIS); |
| 870 | |
| 871 | if (!unpick_msg(st,msgtype,msg3,&m)) return False; |
| 872 | if (!check_msg(st,msgtype,&m,&err)) { |
| 873 | slog(st,LOG_SEC,"msg3: %s",err); |
| 874 | return False; |
| 875 | } |
| 876 | uint32_t capab_adv_late = m.remote_capabilities |
| 877 | & ~st->remote_capabilities & CAPAB_EARLY; |
| 878 | if (capab_adv_late) { |
| 879 | slog(st,LOG_SEC,"msg3 impermissibly adds early capability flag(s)" |
| 880 | " %#"PRIx32" (was %#"PRIx32", now %#"PRIx32")", |
| 881 | capab_adv_late, st->remote_capabilities, m.remote_capabilities); |
| 882 | return False; |
| 883 | } |
| 884 | st->remote_capabilities|=m.remote_capabilities; |
| 885 | |
| 886 | struct transform_if *ti; |
| 887 | int i; |
| 888 | for (i=0; i<st->ntransforms; i++) { |
| 889 | ti=st->transforms[i]; |
| 890 | if (ti->capab_transformnum == m.capab_transformnum) |
| 891 | goto transform_found; |
| 892 | } |
| 893 | slog(st,LOG_SEC,"peer chose unknown-to-us transform %d!", |
| 894 | m.capab_transformnum); |
| 895 | return False; |
| 896 | transform_found: |
| 897 | st->chosen_transform=ti; |
| 898 | |
| 899 | if (!process_msg3_msg4(st,&m)) |
| 900 | return False; |
| 901 | |
| 902 | /* Terminate their DH public key with a '0' */ |
| 903 | m.pk[m.pklen]=0; |
| 904 | /* Invent our DH secret key */ |
| 905 | st->random->generate(st->random->st,st->dh->len,st->dhsecret); |
| 906 | |
| 907 | /* Generate the shared key and set up the transform */ |
| 908 | set_new_transform(st,m.pk); |
| 909 | |
| 910 | return True; |
| 911 | } |
| 912 | |
| 913 | static bool_t generate_msg4(struct site *st) |
| 914 | { |
| 915 | /* We have both nonces, their public key and our private key. Generate |
| 916 | our public key, sign it and send it to them. */ |
| 917 | return generate_msg(st,LABEL_MSG4,"site:MSG4"); |
| 918 | } |
| 919 | |
| 920 | static bool_t process_msg4(struct site *st, struct buffer_if *msg4, |
| 921 | const struct comm_addr *src) |
| 922 | { |
| 923 | struct msg m; |
| 924 | cstring_t err; |
| 925 | |
| 926 | if (!unpick_msg(st,LABEL_MSG4,msg4,&m)) return False; |
| 927 | if (!check_msg(st,LABEL_MSG4,&m,&err)) { |
| 928 | slog(st,LOG_SEC,"msg4: %s",err); |
| 929 | return False; |
| 930 | } |
| 931 | |
| 932 | if (!process_msg3_msg4(st,&m)) |
| 933 | return False; |
| 934 | |
| 935 | /* Terminate their DH public key with a '0' */ |
| 936 | m.pk[m.pklen]=0; |
| 937 | |
| 938 | /* Generate the shared key and set up the transform */ |
| 939 | set_new_transform(st,m.pk); |
| 940 | |
| 941 | return True; |
| 942 | } |
| 943 | |
| 944 | struct msg0 { |
| 945 | uint32_t dest; |
| 946 | uint32_t source; |
| 947 | uint32_t type; |
| 948 | }; |
| 949 | |
| 950 | static bool_t unpick_msg0(struct site *st, struct buffer_if *msg0, |
| 951 | struct msg0 *m) |
| 952 | { |
| 953 | CHECK_AVAIL(msg0,4); |
| 954 | m->dest=buf_unprepend_uint32(msg0); |
| 955 | CHECK_AVAIL(msg0,4); |
| 956 | m->source=buf_unprepend_uint32(msg0); |
| 957 | CHECK_AVAIL(msg0,4); |
| 958 | m->type=buf_unprepend_uint32(msg0); |
| 959 | return True; |
| 960 | /* Leaves transformed part of buffer untouched */ |
| 961 | } |
| 962 | |
| 963 | static bool_t generate_msg5(struct site *st) |
| 964 | { |
| 965 | cstring_t transform_err; |
| 966 | |
| 967 | BUF_ALLOC(&st->buffer,"site:MSG5"); |
| 968 | /* We are going to add four words to the message */ |
| 969 | buffer_init(&st->buffer,calculate_max_start_pad()); |
| 970 | /* Give the netlink code an opportunity to put its own stuff in the |
| 971 | message (configuration information, etc.) */ |
| 972 | buf_prepend_uint32(&st->buffer,LABEL_MSG5); |
| 973 | if (call_transform_forwards(st,st->new_transform, |
| 974 | &st->buffer,&transform_err)) |
| 975 | return False; |
| 976 | buf_prepend_uint32(&st->buffer,LABEL_MSG5); |
| 977 | buf_prepend_uint32(&st->buffer,st->index); |
| 978 | buf_prepend_uint32(&st->buffer,st->setup_session_id); |
| 979 | |
| 980 | st->retries=st->setup_retries; |
| 981 | return True; |
| 982 | } |
| 983 | |
| 984 | static bool_t process_msg5(struct site *st, struct buffer_if *msg5, |
| 985 | const struct comm_addr *src, |
| 986 | struct transform_inst_if *transform) |
| 987 | { |
| 988 | struct msg0 m; |
| 989 | cstring_t transform_err; |
| 990 | |
| 991 | if (!unpick_msg0(st,msg5,&m)) return False; |
| 992 | |
| 993 | if (call_transform_reverse(st,transform,msg5,&transform_err)) { |
| 994 | /* There's a problem */ |
| 995 | slog(st,LOG_SEC,"process_msg5: transform: %s",transform_err); |
| 996 | return False; |
| 997 | } |
| 998 | /* Buffer should now contain untransformed PING packet data */ |
| 999 | CHECK_AVAIL(msg5,4); |
| 1000 | if (buf_unprepend_uint32(msg5)!=LABEL_MSG5) { |
| 1001 | slog(st,LOG_SEC,"MSG5/PING packet contained wrong label"); |
| 1002 | return False; |
| 1003 | } |
| 1004 | /* Older versions of secnet used to write some config data here |
| 1005 | * which we ignore. So we don't CHECK_EMPTY */ |
| 1006 | return True; |
| 1007 | } |
| 1008 | |
| 1009 | static void create_msg6(struct site *st, struct transform_inst_if *transform, |
| 1010 | uint32_t session_id) |
| 1011 | { |
| 1012 | cstring_t transform_err; |
| 1013 | |
| 1014 | BUF_ALLOC(&st->buffer,"site:MSG6"); |
| 1015 | /* We are going to add four words to the message */ |
| 1016 | buffer_init(&st->buffer,calculate_max_start_pad()); |
| 1017 | /* Give the netlink code an opportunity to put its own stuff in the |
| 1018 | message (configuration information, etc.) */ |
| 1019 | buf_prepend_uint32(&st->buffer,LABEL_MSG6); |
| 1020 | int problem = call_transform_forwards(st,transform, |
| 1021 | &st->buffer,&transform_err); |
| 1022 | assert(!problem); |
| 1023 | buf_prepend_uint32(&st->buffer,LABEL_MSG6); |
| 1024 | buf_prepend_uint32(&st->buffer,st->index); |
| 1025 | buf_prepend_uint32(&st->buffer,session_id); |
| 1026 | } |
| 1027 | |
| 1028 | static bool_t generate_msg6(struct site *st) |
| 1029 | { |
| 1030 | if (!is_transform_valid(st->new_transform)) |
| 1031 | return False; |
| 1032 | create_msg6(st,st->new_transform,st->setup_session_id); |
| 1033 | st->retries=1; /* Peer will retransmit MSG5 if this packet gets lost */ |
| 1034 | return True; |
| 1035 | } |
| 1036 | |
| 1037 | static bool_t process_msg6(struct site *st, struct buffer_if *msg6, |
| 1038 | const struct comm_addr *src) |
| 1039 | { |
| 1040 | struct msg0 m; |
| 1041 | cstring_t transform_err; |
| 1042 | |
| 1043 | if (!unpick_msg0(st,msg6,&m)) return False; |
| 1044 | |
| 1045 | if (call_transform_reverse(st,st->new_transform,msg6,&transform_err)) { |
| 1046 | /* There's a problem */ |
| 1047 | slog(st,LOG_SEC,"process_msg6: transform: %s",transform_err); |
| 1048 | return False; |
| 1049 | } |
| 1050 | /* Buffer should now contain untransformed PING packet data */ |
| 1051 | CHECK_AVAIL(msg6,4); |
| 1052 | if (buf_unprepend_uint32(msg6)!=LABEL_MSG6) { |
| 1053 | slog(st,LOG_SEC,"MSG6/PONG packet contained invalid data"); |
| 1054 | return False; |
| 1055 | } |
| 1056 | /* Older versions of secnet used to write some config data here |
| 1057 | * which we ignore. So we don't CHECK_EMPTY */ |
| 1058 | return True; |
| 1059 | } |
| 1060 | |
| 1061 | static bool_t decrypt_msg0(struct site *st, struct buffer_if *msg0, |
| 1062 | const struct comm_addr *src) |
| 1063 | { |
| 1064 | cstring_t transform_err, auxkey_err, newkey_err="n/a"; |
| 1065 | struct msg0 m; |
| 1066 | uint32_t problem; |
| 1067 | |
| 1068 | if (!unpick_msg0(st,msg0,&m)) return False; |
| 1069 | |
| 1070 | /* Keep a copy so we can try decrypting it with multiple keys */ |
| 1071 | buffer_copy(&st->scratch, msg0); |
| 1072 | |
| 1073 | problem = call_transform_reverse(st,st->current.transform, |
| 1074 | msg0,&transform_err); |
| 1075 | if (!problem) { |
| 1076 | if (!st->auxiliary_is_new) |
| 1077 | delete_one_key(st,&st->auxiliary_key, |
| 1078 | "peer has used new key","auxiliary key",LOG_SEC); |
| 1079 | return True; |
| 1080 | } |
| 1081 | if (problem==2) |
| 1082 | goto skew; |
| 1083 | |
| 1084 | buffer_copy(msg0, &st->scratch); |
| 1085 | problem = call_transform_reverse(st,st->auxiliary_key.transform, |
| 1086 | msg0,&auxkey_err); |
| 1087 | if (problem==0) { |
| 1088 | slog(st,LOG_DROP,"processing packet which uses auxiliary key"); |
| 1089 | if (st->auxiliary_is_new) { |
| 1090 | /* We previously timed out in state SENTMSG5 but it turns |
| 1091 | * out that our peer did in fact get our MSG5 and is |
| 1092 | * using the new key. So we should switch to it too. */ |
| 1093 | /* This is a bit like activate_new_key. */ |
| 1094 | struct data_key t; |
| 1095 | t=st->current; |
| 1096 | st->current=st->auxiliary_key; |
| 1097 | st->auxiliary_key=t; |
| 1098 | |
| 1099 | delete_one_key(st,&st->auxiliary_key,"peer has used new key", |
| 1100 | "previous key",LOG_SEC); |
| 1101 | st->auxiliary_is_new=0; |
| 1102 | st->renegotiate_key_time=st->auxiliary_renegotiate_key_time; |
| 1103 | } |
| 1104 | return True; |
| 1105 | } |
| 1106 | if (problem==2) |
| 1107 | goto skew; |
| 1108 | |
| 1109 | if (st->state==SITE_SENTMSG5) { |
| 1110 | buffer_copy(msg0, &st->scratch); |
| 1111 | problem = call_transform_reverse(st,st->new_transform, |
| 1112 | msg0,&newkey_err); |
| 1113 | if (!problem) { |
| 1114 | /* It looks like we didn't get the peer's MSG6 */ |
| 1115 | /* This is like a cut-down enter_new_state(SITE_RUN) */ |
| 1116 | slog(st,LOG_STATE,"will enter state RUN (MSG0 with new key)"); |
| 1117 | BUF_FREE(&st->buffer); |
| 1118 | st->timeout=0; |
| 1119 | activate_new_key(st); |
| 1120 | return True; /* do process the data in this packet */ |
| 1121 | } |
| 1122 | if (problem==2) |
| 1123 | goto skew; |
| 1124 | } |
| 1125 | |
| 1126 | slog(st,LOG_SEC,"transform: %s (aux: %s, new: %s)", |
| 1127 | transform_err,auxkey_err,newkey_err); |
| 1128 | initiate_key_setup(st,"incoming message would not decrypt",0); |
| 1129 | send_nak(src,m.dest,m.source,m.type,msg0,"message would not decrypt"); |
| 1130 | return False; |
| 1131 | |
| 1132 | skew: |
| 1133 | slog(st,LOG_DROP,"transform: %s (merely skew)",transform_err); |
| 1134 | return False; |
| 1135 | } |
| 1136 | |
| 1137 | static bool_t process_msg0(struct site *st, struct buffer_if *msg0, |
| 1138 | const struct comm_addr *src) |
| 1139 | { |
| 1140 | uint32_t type; |
| 1141 | |
| 1142 | if (!decrypt_msg0(st,msg0,src)) |
| 1143 | return False; |
| 1144 | |
| 1145 | CHECK_AVAIL(msg0,4); |
| 1146 | type=buf_unprepend_uint32(msg0); |
| 1147 | switch(type) { |
| 1148 | case LABEL_MSG7: |
| 1149 | /* We must forget about the current session. */ |
| 1150 | delete_keys(st,"request from peer",LOG_SEC); |
| 1151 | /* probably, the peer is shutting down, and this is going to fail, |
| 1152 | * but we need to be trying to bring the link up again */ |
| 1153 | if (st->keepalive) |
| 1154 | initiate_key_setup(st,"peer requested key teardown",0); |
| 1155 | return True; |
| 1156 | case LABEL_MSG9: |
| 1157 | /* Deliver to netlink layer */ |
| 1158 | st->netlink->deliver(st->netlink->st,msg0); |
| 1159 | transport_data_msgok(st,src); |
| 1160 | /* See whether we should start negotiating a new key */ |
| 1161 | if (st->now > st->renegotiate_key_time) |
| 1162 | initiate_key_setup(st,"incoming packet in renegotiation window",0); |
| 1163 | return True; |
| 1164 | default: |
| 1165 | slog(st,LOG_SEC,"incoming encrypted message of type %08x " |
| 1166 | "(unknown)",type); |
| 1167 | break; |
| 1168 | } |
| 1169 | return False; |
| 1170 | } |
| 1171 | |
| 1172 | static void dump_packet(struct site *st, struct buffer_if *buf, |
| 1173 | const struct comm_addr *addr, bool_t incoming, |
| 1174 | bool_t ok) |
| 1175 | { |
| 1176 | uint32_t dest=get_uint32(buf->start); |
| 1177 | uint32_t source=get_uint32(buf->start+4); |
| 1178 | uint32_t msgtype=get_uint32(buf->start+8); |
| 1179 | |
| 1180 | if (st->log_events & LOG_DUMP) |
| 1181 | slilog(st->log,M_DEBUG,"%s: %s: %08x<-%08x: %08x: %s%s", |
| 1182 | st->tunname,incoming?"incoming":"outgoing", |
| 1183 | dest,source,msgtype,comm_addr_to_string(addr), |
| 1184 | ok?"":" - fail"); |
| 1185 | } |
| 1186 | |
| 1187 | static bool_t comm_addr_sendmsg(struct site *st, |
| 1188 | const struct comm_addr *dest, |
| 1189 | struct buffer_if *buf) |
| 1190 | { |
| 1191 | int i; |
| 1192 | struct comm_clientinfo *commclientinfo = 0; |
| 1193 | |
| 1194 | for (i=0; i < st->ncomms; i++) { |
| 1195 | if (st->comms[i] == dest->comm) { |
| 1196 | commclientinfo = st->commclientinfos[i]; |
| 1197 | break; |
| 1198 | } |
| 1199 | } |
| 1200 | return dest->comm->sendmsg(dest->comm->st, buf, dest, commclientinfo); |
| 1201 | } |
| 1202 | |
| 1203 | static uint32_t site_status(void *st) |
| 1204 | { |
| 1205 | return 0; |
| 1206 | } |
| 1207 | |
| 1208 | static bool_t send_msg(struct site *st) |
| 1209 | { |
| 1210 | if (st->retries>0) { |
| 1211 | transport_xmit(st, &st->setup_peers, &st->buffer, True); |
| 1212 | st->timeout=st->now+st->setup_retry_interval; |
| 1213 | st->retries--; |
| 1214 | return True; |
| 1215 | } else if (st->state==SITE_SENTMSG5) { |
| 1216 | logtimeout(st,"timed out sending MSG5, stashing new key"); |
| 1217 | /* We stash the key we have produced, in case it turns out that |
| 1218 | * our peer did see our MSG5 after all and starts using it. */ |
| 1219 | /* This is a bit like some of activate_new_key */ |
| 1220 | struct transform_inst_if *t; |
| 1221 | t=st->auxiliary_key.transform; |
| 1222 | st->auxiliary_key.transform=st->new_transform; |
| 1223 | st->new_transform=t; |
| 1224 | dispose_transform(&st->new_transform); |
| 1225 | |
| 1226 | st->auxiliary_is_new=1; |
| 1227 | st->auxiliary_key.key_timeout=st->now+st->key_lifetime; |
| 1228 | st->auxiliary_renegotiate_key_time=st->now+st->key_renegotiate_time; |
| 1229 | st->auxiliary_key.remote_session_id=st->setup_session_id; |
| 1230 | |
| 1231 | enter_state_wait(st); |
| 1232 | return False; |
| 1233 | } else { |
| 1234 | logtimeout(st,"timed out sending key setup packet " |
| 1235 | "(in state %s)",state_name(st->state)); |
| 1236 | enter_state_wait(st); |
| 1237 | return False; |
| 1238 | } |
| 1239 | } |
| 1240 | |
| 1241 | static void site_resolve_callback(void *sst, const struct comm_addr *addrs, |
| 1242 | int stored_naddrs, int all_naddrs, |
| 1243 | const char *address, const char *failwhy) |
| 1244 | { |
| 1245 | struct site *st=sst; |
| 1246 | |
| 1247 | if (!stored_naddrs) { |
| 1248 | slog(st,LOG_ERROR,"resolution of %s failed: %s",address,failwhy); |
| 1249 | } else { |
| 1250 | slog(st,LOG_PEER_ADDRS,"resolution of %s completed, %d addrs, eg: %s", |
| 1251 | address, all_naddrs, comm_addr_to_string(&addrs[0]));; |
| 1252 | |
| 1253 | int space=st->transport_peers_max-st->resolving_n_results_stored; |
| 1254 | int n_tocopy=MIN(stored_naddrs,space); |
| 1255 | COPY_ARRAY(st->resolving_results + st->resolving_n_results_stored, |
| 1256 | addrs, |
| 1257 | n_tocopy); |
| 1258 | st->resolving_n_results_stored += n_tocopy; |
| 1259 | st->resolving_n_results_all += all_naddrs; |
| 1260 | } |
| 1261 | |
| 1262 | decrement_resolving_count(st,1); |
| 1263 | } |
| 1264 | |
| 1265 | static void decrement_resolving_count(struct site *st, int by) |
| 1266 | { |
| 1267 | assert(st->resolving_count>0); |
| 1268 | st->resolving_count-=by; |
| 1269 | |
| 1270 | if (st->resolving_count) |
| 1271 | return; |
| 1272 | |
| 1273 | /* OK, we are done with them all. Handle combined results. */ |
| 1274 | |
| 1275 | const struct comm_addr *addrs=st->resolving_results; |
| 1276 | int naddrs=st->resolving_n_results_stored; |
| 1277 | assert(naddrs<=st->transport_peers_max); |
| 1278 | |
| 1279 | if (naddrs) { |
| 1280 | if (naddrs != st->resolving_n_results_all) { |
| 1281 | slog(st,LOG_SETUP_INIT,"resolution of supplied addresses/names" |
| 1282 | " yielded too many results (%d > %d), some ignored", |
| 1283 | st->resolving_n_results_all, naddrs); |
| 1284 | } |
| 1285 | slog(st,LOG_STATE,"resolution completed, %d addrs, eg: %s", |
| 1286 | naddrs, iaddr_to_string(&addrs[0].ia));; |
| 1287 | } |
| 1288 | |
| 1289 | switch (st->state) { |
| 1290 | case SITE_RESOLVE: |
| 1291 | if (transport_compute_setupinit_peers(st,addrs,naddrs,0)) { |
| 1292 | enter_new_state(st,SITE_SENTMSG1); |
| 1293 | } else { |
| 1294 | /* Can't figure out who to try to to talk to */ |
| 1295 | slog(st,LOG_SETUP_INIT, |
| 1296 | "key exchange failed: cannot find peer address"); |
| 1297 | enter_state_run(st); |
| 1298 | } |
| 1299 | break; |
| 1300 | case SITE_SENTMSG1: case SITE_SENTMSG2: |
| 1301 | case SITE_SENTMSG3: case SITE_SENTMSG4: |
| 1302 | case SITE_SENTMSG5: |
| 1303 | if (naddrs) { |
| 1304 | /* We start using the address immediately for data too. |
| 1305 | * It's best to store it in st->peers now because we might |
| 1306 | * go via SENTMSG5, WAIT, and a MSG0, straight into using |
| 1307 | * the new key (without updating the data peer addrs). */ |
| 1308 | transport_resolve_complete(st,addrs,naddrs); |
| 1309 | } else if (st->local_mobile) { |
| 1310 | /* We can't let this rest because we may have a peer |
| 1311 | * address which will break in the future. */ |
| 1312 | slog(st,LOG_SETUP_INIT,"resolution failed: " |
| 1313 | "abandoning key exchange"); |
| 1314 | enter_state_wait(st); |
| 1315 | } else { |
| 1316 | slog(st,LOG_SETUP_INIT,"resolution failed: " |
| 1317 | " continuing to use source address of peer's packets" |
| 1318 | " for key exchange and ultimately data"); |
| 1319 | } |
| 1320 | break; |
| 1321 | case SITE_RUN: |
| 1322 | if (naddrs) { |
| 1323 | slog(st,LOG_SETUP_INIT,"resolution completed tardily," |
| 1324 | " updating peer address(es)"); |
| 1325 | transport_resolve_complete_tardy(st,addrs,naddrs); |
| 1326 | } else if (st->local_mobile) { |
| 1327 | /* Not very good. We should queue (another) renegotiation |
| 1328 | * so that we can update the peer address. */ |
| 1329 | st->key_renegotiate_time=st->now+st->wait_timeout; |
| 1330 | } else { |
| 1331 | slog(st,LOG_SETUP_INIT,"resolution failed: " |
| 1332 | " continuing to use source address of peer's packets"); |
| 1333 | } |
| 1334 | break; |
| 1335 | case SITE_WAIT: |
| 1336 | case SITE_STOP: |
| 1337 | /* oh well */ |
| 1338 | break; |
| 1339 | } |
| 1340 | } |
| 1341 | |
| 1342 | static bool_t initiate_key_setup(struct site *st, cstring_t reason, |
| 1343 | const struct comm_addr *prod_hint) |
| 1344 | { |
| 1345 | /* Reentrancy hazard: can call enter_new_state/enter_state_* */ |
| 1346 | if (st->state!=SITE_RUN) return False; |
| 1347 | slog(st,LOG_SETUP_INIT,"initiating key exchange (%s)",reason); |
| 1348 | if (st->addresses) { |
| 1349 | slog(st,LOG_SETUP_INIT,"resolving peer address(es)"); |
| 1350 | return enter_state_resolve(st); |
| 1351 | } else if (transport_compute_setupinit_peers(st,0,0,prod_hint)) { |
| 1352 | return enter_new_state(st,SITE_SENTMSG1); |
| 1353 | } |
| 1354 | slog(st,LOG_SETUP_INIT,"key exchange failed: no address for peer"); |
| 1355 | return False; |
| 1356 | } |
| 1357 | |
| 1358 | static void activate_new_key(struct site *st) |
| 1359 | { |
| 1360 | struct transform_inst_if *t; |
| 1361 | |
| 1362 | /* We have three transform instances, which we swap between old, |
| 1363 | active and setup */ |
| 1364 | t=st->auxiliary_key.transform; |
| 1365 | st->auxiliary_key.transform=st->current.transform; |
| 1366 | st->current.transform=st->new_transform; |
| 1367 | st->new_transform=t; |
| 1368 | dispose_transform(&st->new_transform); |
| 1369 | |
| 1370 | st->timeout=0; |
| 1371 | st->auxiliary_is_new=0; |
| 1372 | st->auxiliary_key.key_timeout=st->current.key_timeout; |
| 1373 | st->current.key_timeout=st->now+st->key_lifetime; |
| 1374 | st->renegotiate_key_time=st->now+st->key_renegotiate_time; |
| 1375 | transport_peers_copy(st,&st->peers,&st->setup_peers); |
| 1376 | st->current.remote_session_id=st->setup_session_id; |
| 1377 | |
| 1378 | /* Compute the inter-site MTU. This is min( our_mtu, their_mtu ). |
| 1379 | * But their mtu be unspecified, in which case we just use ours. */ |
| 1380 | uint32_t intersite_mtu= |
| 1381 | MIN(st->mtu_target, st->remote_adv_mtu ?: ~(uint32_t)0); |
| 1382 | st->netlink->set_mtu(st->netlink->st,intersite_mtu); |
| 1383 | |
| 1384 | slog(st,LOG_ACTIVATE_KEY,"new key activated" |
| 1385 | " (mtu ours=%"PRId32" theirs=%"PRId32" intersite=%"PRId32")", |
| 1386 | st->mtu_target, st->remote_adv_mtu, intersite_mtu); |
| 1387 | enter_state_run(st); |
| 1388 | } |
| 1389 | |
| 1390 | static void delete_one_key(struct site *st, struct data_key *key, |
| 1391 | cstring_t reason, cstring_t which, uint32_t loglevel) |
| 1392 | { |
| 1393 | if (!is_transform_valid(key->transform)) return; |
| 1394 | if (reason) slog(st,loglevel,"%s deleted (%s)",which,reason); |
| 1395 | dispose_transform(&key->transform); |
| 1396 | key->key_timeout=0; |
| 1397 | } |
| 1398 | |
| 1399 | static void delete_keys(struct site *st, cstring_t reason, uint32_t loglevel) |
| 1400 | { |
| 1401 | if (current_valid(st)) { |
| 1402 | slog(st,loglevel,"session closed (%s)",reason); |
| 1403 | |
| 1404 | delete_one_key(st,&st->current,0,0,0); |
| 1405 | set_link_quality(st); |
| 1406 | } |
| 1407 | delete_one_key(st,&st->auxiliary_key,0,0,0); |
| 1408 | } |
| 1409 | |
| 1410 | static void state_assert(struct site *st, bool_t ok) |
| 1411 | { |
| 1412 | if (!ok) fatal("site:state_assert"); |
| 1413 | } |
| 1414 | |
| 1415 | static void enter_state_stop(struct site *st) |
| 1416 | { |
| 1417 | st->state=SITE_STOP; |
| 1418 | st->timeout=0; |
| 1419 | delete_keys(st,"entering state STOP",LOG_TIMEOUT_KEY); |
| 1420 | dispose_transform(&st->new_transform); |
| 1421 | } |
| 1422 | |
| 1423 | static void set_link_quality(struct site *st) |
| 1424 | { |
| 1425 | uint32_t quality; |
| 1426 | if (current_valid(st)) |
| 1427 | quality=LINK_QUALITY_UP; |
| 1428 | else if (st->state==SITE_WAIT || st->state==SITE_STOP) |
| 1429 | quality=LINK_QUALITY_DOWN; |
| 1430 | else if (st->addresses) |
| 1431 | quality=LINK_QUALITY_DOWN_CURRENT_ADDRESS; |
| 1432 | else if (transport_peers_valid(&st->peers)) |
| 1433 | quality=LINK_QUALITY_DOWN_STALE_ADDRESS; |
| 1434 | else |
| 1435 | quality=LINK_QUALITY_DOWN; |
| 1436 | |
| 1437 | st->netlink->set_quality(st->netlink->st,quality); |
| 1438 | } |
| 1439 | |
| 1440 | static void enter_state_run(struct site *st) |
| 1441 | { |
| 1442 | slog(st,LOG_STATE,"entering state RUN"); |
| 1443 | st->state=SITE_RUN; |
| 1444 | st->timeout=0; |
| 1445 | |
| 1446 | st->setup_session_id=0; |
| 1447 | transport_peers_clear(st,&st->setup_peers); |
| 1448 | FILLZERO(st->localN); |
| 1449 | FILLZERO(st->remoteN); |
| 1450 | dispose_transform(&st->new_transform); |
| 1451 | memset(st->dhsecret,0,st->dh->len); |
| 1452 | memset(st->sharedsecret,0,st->sharedsecretlen); |
| 1453 | set_link_quality(st); |
| 1454 | |
| 1455 | if (st->keepalive && !current_valid(st)) |
| 1456 | initiate_key_setup(st, "keepalive", 0); |
| 1457 | } |
| 1458 | |
| 1459 | static bool_t ensure_resolving(struct site *st) |
| 1460 | { |
| 1461 | /* Reentrancy hazard: may call site_resolve_callback and hence |
| 1462 | * enter_new_state, enter_state_* and generate_msg*. */ |
| 1463 | if (st->resolving_count) |
| 1464 | return True; |
| 1465 | |
| 1466 | assert(st->addresses); |
| 1467 | |
| 1468 | /* resolver->request might reentrantly call site_resolve_callback |
| 1469 | * which will decrement st->resolving, so we need to increment it |
| 1470 | * twice beforehand to prevent decrement from thinking we're |
| 1471 | * finished, and decrement it ourselves. Alternatively if |
| 1472 | * everything fails then there are no callbacks due and we simply |
| 1473 | * set it to 0 and return false.. */ |
| 1474 | st->resolving_n_results_stored=0; |
| 1475 | st->resolving_n_results_all=0; |
| 1476 | st->resolving_count+=2; |
| 1477 | const char **addrp=st->addresses; |
| 1478 | const char *address; |
| 1479 | bool_t anyok=False; |
| 1480 | for (; (address=*addrp++); ) { |
| 1481 | bool_t ok = st->resolver->request(st->resolver->st,address, |
| 1482 | st->remoteport,st->comms[0], |
| 1483 | site_resolve_callback,st); |
| 1484 | if (ok) |
| 1485 | st->resolving_count++; |
| 1486 | anyok|=ok; |
| 1487 | } |
| 1488 | if (!anyok) { |
| 1489 | st->resolving_count=0; |
| 1490 | return False; |
| 1491 | } |
| 1492 | decrement_resolving_count(st,2); |
| 1493 | return True; |
| 1494 | } |
| 1495 | |
| 1496 | static bool_t enter_state_resolve(struct site *st) |
| 1497 | { |
| 1498 | /* Reentrancy hazard! See ensure_resolving. */ |
| 1499 | state_assert(st,st->state==SITE_RUN); |
| 1500 | slog(st,LOG_STATE,"entering state RESOLVE"); |
| 1501 | st->state=SITE_RESOLVE; |
| 1502 | return ensure_resolving(st); |
| 1503 | } |
| 1504 | |
| 1505 | static bool_t enter_new_state(struct site *st, uint32_t next) |
| 1506 | { |
| 1507 | bool_t (*gen)(struct site *st); |
| 1508 | int r; |
| 1509 | |
| 1510 | slog(st,LOG_STATE,"entering state %s",state_name(next)); |
| 1511 | switch(next) { |
| 1512 | case SITE_SENTMSG1: |
| 1513 | state_assert(st,st->state==SITE_RUN || st->state==SITE_RESOLVE); |
| 1514 | gen=generate_msg1; |
| 1515 | break; |
| 1516 | case SITE_SENTMSG2: |
| 1517 | state_assert(st,st->state==SITE_RUN || st->state==SITE_RESOLVE || |
| 1518 | st->state==SITE_SENTMSG1 || st->state==SITE_WAIT); |
| 1519 | gen=generate_msg2; |
| 1520 | break; |
| 1521 | case SITE_SENTMSG3: |
| 1522 | state_assert(st,st->state==SITE_SENTMSG1); |
| 1523 | BUF_FREE(&st->buffer); |
| 1524 | gen=generate_msg3; |
| 1525 | break; |
| 1526 | case SITE_SENTMSG4: |
| 1527 | state_assert(st,st->state==SITE_SENTMSG2); |
| 1528 | BUF_FREE(&st->buffer); |
| 1529 | gen=generate_msg4; |
| 1530 | break; |
| 1531 | case SITE_SENTMSG5: |
| 1532 | state_assert(st,st->state==SITE_SENTMSG3); |
| 1533 | BUF_FREE(&st->buffer); |
| 1534 | gen=generate_msg5; |
| 1535 | break; |
| 1536 | case SITE_RUN: |
| 1537 | state_assert(st,st->state==SITE_SENTMSG4); |
| 1538 | BUF_FREE(&st->buffer); |
| 1539 | gen=generate_msg6; |
| 1540 | break; |
| 1541 | default: |
| 1542 | gen=NULL; |
| 1543 | fatal("enter_new_state(%s): invalid new state",state_name(next)); |
| 1544 | break; |
| 1545 | } |
| 1546 | |
| 1547 | if (hacky_par_start_failnow()) return False; |
| 1548 | |
| 1549 | r= gen(st) && send_msg(st); |
| 1550 | |
| 1551 | hacky_par_end(&r, |
| 1552 | st->setup_retries, st->setup_retry_interval, |
| 1553 | send_msg, st); |
| 1554 | |
| 1555 | if (r) { |
| 1556 | st->state=next; |
| 1557 | if (next==SITE_RUN) { |
| 1558 | BUF_FREE(&st->buffer); /* Never reused */ |
| 1559 | st->timeout=0; /* Never retransmit */ |
| 1560 | activate_new_key(st); |
| 1561 | } |
| 1562 | return True; |
| 1563 | } |
| 1564 | slog(st,LOG_ERROR,"error entering state %s",state_name(next)); |
| 1565 | st->buffer.free=False; /* Unconditionally use the buffer; it may be |
| 1566 | in either state, and enter_state_wait() will |
| 1567 | do a BUF_FREE() */ |
| 1568 | enter_state_wait(st); |
| 1569 | return False; |
| 1570 | } |
| 1571 | |
| 1572 | /* msg7 tells our peer that we're about to forget our key */ |
| 1573 | static bool_t send_msg7(struct site *st, cstring_t reason) |
| 1574 | { |
| 1575 | cstring_t transform_err; |
| 1576 | |
| 1577 | if (current_valid(st) && st->buffer.free |
| 1578 | && transport_peers_valid(&st->peers)) { |
| 1579 | BUF_ALLOC(&st->buffer,"site:MSG7"); |
| 1580 | buffer_init(&st->buffer,calculate_max_start_pad()); |
| 1581 | buf_append_uint32(&st->buffer,LABEL_MSG7); |
| 1582 | buf_append_string(&st->buffer,reason); |
| 1583 | if (call_transform_forwards(st, st->current.transform, |
| 1584 | &st->buffer, &transform_err)) |
| 1585 | goto free_out; |
| 1586 | buf_prepend_uint32(&st->buffer,LABEL_MSG0); |
| 1587 | buf_prepend_uint32(&st->buffer,st->index); |
| 1588 | buf_prepend_uint32(&st->buffer,st->current.remote_session_id); |
| 1589 | transport_xmit(st,&st->peers,&st->buffer,True); |
| 1590 | BUF_FREE(&st->buffer); |
| 1591 | free_out: |
| 1592 | return True; |
| 1593 | } |
| 1594 | return False; |
| 1595 | } |
| 1596 | |
| 1597 | /* We go into this state if our peer becomes uncommunicative. Similar to |
| 1598 | the "stop" state, we forget all session keys for a while, before |
| 1599 | re-entering the "run" state. */ |
| 1600 | static void enter_state_wait(struct site *st) |
| 1601 | { |
| 1602 | slog(st,LOG_STATE,"entering state WAIT"); |
| 1603 | st->timeout=st->now+st->wait_timeout; |
| 1604 | st->state=SITE_WAIT; |
| 1605 | set_link_quality(st); |
| 1606 | BUF_FREE(&st->buffer); /* will have had an outgoing packet in it */ |
| 1607 | /* XXX Erase keys etc. */ |
| 1608 | } |
| 1609 | |
| 1610 | static void generate_prod(struct site *st, struct buffer_if *buf) |
| 1611 | { |
| 1612 | buffer_init(buf,0); |
| 1613 | buf_append_uint32(buf,0); |
| 1614 | buf_append_uint32(buf,0); |
| 1615 | buf_append_uint32(buf,LABEL_PROD); |
| 1616 | buf_append_string(buf,st->localname); |
| 1617 | buf_append_string(buf,st->remotename); |
| 1618 | } |
| 1619 | |
| 1620 | static void generate_send_prod(struct site *st, |
| 1621 | const struct comm_addr *source) |
| 1622 | { |
| 1623 | if (!st->allow_send_prod) return; /* too soon */ |
| 1624 | if (!(st->state==SITE_RUN || st->state==SITE_RESOLVE || |
| 1625 | st->state==SITE_WAIT)) return; /* we'd ignore peer's MSG1 */ |
| 1626 | |
| 1627 | slog(st,LOG_SETUP_INIT,"prodding peer for key exchange"); |
| 1628 | st->allow_send_prod=0; |
| 1629 | generate_prod(st,&st->scratch); |
| 1630 | bool_t ok = comm_addr_sendmsg(st, source, &st->scratch); |
| 1631 | dump_packet(st,&st->scratch,source,False,ok); |
| 1632 | } |
| 1633 | |
| 1634 | static inline void site_settimeout(uint64_t timeout, int *timeout_io) |
| 1635 | { |
| 1636 | if (timeout) { |
| 1637 | int64_t offset=timeout-*now; |
| 1638 | if (offset<0) offset=0; |
| 1639 | if (offset>INT_MAX) offset=INT_MAX; |
| 1640 | if (*timeout_io<0 || offset<*timeout_io) |
| 1641 | *timeout_io=offset; |
| 1642 | } |
| 1643 | } |
| 1644 | |
| 1645 | static int site_beforepoll(void *sst, struct pollfd *fds, int *nfds_io, |
| 1646 | int *timeout_io) |
| 1647 | { |
| 1648 | struct site *st=sst; |
| 1649 | |
| 1650 | BEFOREPOLL_WANT_FDS(0); /* We don't use any file descriptors */ |
| 1651 | st->now=*now; |
| 1652 | |
| 1653 | /* Work out when our next timeout is. The earlier of 'timeout' or |
| 1654 | 'current.key_timeout'. A stored value of '0' indicates no timeout |
| 1655 | active. */ |
| 1656 | site_settimeout(st->timeout, timeout_io); |
| 1657 | site_settimeout(st->current.key_timeout, timeout_io); |
| 1658 | site_settimeout(st->auxiliary_key.key_timeout, timeout_io); |
| 1659 | |
| 1660 | return 0; /* success */ |
| 1661 | } |
| 1662 | |
| 1663 | static void check_expiry(struct site *st, struct data_key *key, |
| 1664 | const char *which) |
| 1665 | { |
| 1666 | if (key->key_timeout && *now>key->key_timeout) { |
| 1667 | delete_one_key(st,key,"maximum life exceeded",which,LOG_TIMEOUT_KEY); |
| 1668 | } |
| 1669 | } |
| 1670 | |
| 1671 | /* NB site_afterpoll will be called before site_beforepoll is ever called */ |
| 1672 | static void site_afterpoll(void *sst, struct pollfd *fds, int nfds) |
| 1673 | { |
| 1674 | struct site *st=sst; |
| 1675 | |
| 1676 | st->now=*now; |
| 1677 | if (st->timeout && *now>st->timeout) { |
| 1678 | st->timeout=0; |
| 1679 | if (st->state>=SITE_SENTMSG1 && st->state<=SITE_SENTMSG5) { |
| 1680 | if (!hacky_par_start_failnow()) |
| 1681 | send_msg(st); |
| 1682 | } else if (st->state==SITE_WAIT) { |
| 1683 | enter_state_run(st); |
| 1684 | } else { |
| 1685 | slog(st,LOG_ERROR,"site_afterpoll: unexpected timeout, state=%d", |
| 1686 | st->state); |
| 1687 | } |
| 1688 | } |
| 1689 | check_expiry(st,&st->current,"current key"); |
| 1690 | check_expiry(st,&st->auxiliary_key,"auxiliary key"); |
| 1691 | } |
| 1692 | |
| 1693 | /* This function is called by the netlink device to deliver packets |
| 1694 | intended for the remote network. The packet is in "raw" wire |
| 1695 | format, but is guaranteed to be word-aligned. */ |
| 1696 | static void site_outgoing(void *sst, struct buffer_if *buf) |
| 1697 | { |
| 1698 | struct site *st=sst; |
| 1699 | cstring_t transform_err; |
| 1700 | |
| 1701 | if (st->state==SITE_STOP) { |
| 1702 | BUF_FREE(buf); |
| 1703 | return; |
| 1704 | } |
| 1705 | |
| 1706 | st->allow_send_prod=1; |
| 1707 | |
| 1708 | /* In all other states we consider delivering the packet if we have |
| 1709 | a valid key and a valid address to send it to. */ |
| 1710 | if (current_valid(st) && transport_peers_valid(&st->peers)) { |
| 1711 | /* Transform it and send it */ |
| 1712 | if (buf->size>0) { |
| 1713 | buf_prepend_uint32(buf,LABEL_MSG9); |
| 1714 | if (call_transform_forwards(st, st->current.transform, |
| 1715 | buf, &transform_err)) |
| 1716 | goto free_out; |
| 1717 | buf_prepend_uint32(buf,LABEL_MSG0); |
| 1718 | buf_prepend_uint32(buf,st->index); |
| 1719 | buf_prepend_uint32(buf,st->current.remote_session_id); |
| 1720 | transport_xmit(st,&st->peers,buf,False); |
| 1721 | } |
| 1722 | free_out: |
| 1723 | BUF_FREE(buf); |
| 1724 | return; |
| 1725 | } |
| 1726 | |
| 1727 | slog(st,LOG_DROP,"discarding outgoing packet of size %d",buf->size); |
| 1728 | BUF_FREE(buf); |
| 1729 | initiate_key_setup(st,"outgoing packet",0); |
| 1730 | } |
| 1731 | |
| 1732 | static bool_t named_for_us(struct site *st, const struct buffer_if *buf_in, |
| 1733 | uint32_t type, struct msg *m) |
| 1734 | /* For packets which are identified by the local and remote names. |
| 1735 | * If it has our name and our peer's name in it it's for us. */ |
| 1736 | { |
| 1737 | struct buffer_if buf[1]; |
| 1738 | buffer_readonly_clone(buf,buf_in); |
| 1739 | return unpick_msg(st,type,buf,m) |
| 1740 | && name_matches(&m->remote,st->remotename) |
| 1741 | && name_matches(&m->local,st->localname); |
| 1742 | } |
| 1743 | |
| 1744 | /* This function is called by the communication device to deliver |
| 1745 | packets from our peers. |
| 1746 | It should return True if the packet is recognised as being for |
| 1747 | this current site instance (and should therefore not be processed |
| 1748 | by other sites), even if the packet was otherwise ignored. */ |
| 1749 | static bool_t site_incoming(void *sst, struct buffer_if *buf, |
| 1750 | const struct comm_addr *source) |
| 1751 | { |
| 1752 | struct site *st=sst; |
| 1753 | |
| 1754 | if (buf->size < 12) return False; |
| 1755 | |
| 1756 | uint32_t dest=get_uint32(buf->start); |
| 1757 | uint32_t msgtype=get_uint32(buf->start+8); |
| 1758 | struct msg named_msg; |
| 1759 | |
| 1760 | if (msgtype==LABEL_MSG1) { |
| 1761 | if (!named_for_us(st,buf,msgtype,&named_msg)) |
| 1762 | return False; |
| 1763 | /* It's a MSG1 addressed to us. Decide what to do about it. */ |
| 1764 | dump_packet(st,buf,source,True,True); |
| 1765 | if (st->state==SITE_RUN || st->state==SITE_RESOLVE || |
| 1766 | st->state==SITE_WAIT) { |
| 1767 | /* We should definitely process it */ |
| 1768 | transport_compute_setupinit_peers(st,0,0,source); |
| 1769 | if (process_msg1(st,buf,source,&named_msg)) { |
| 1770 | slog(st,LOG_SETUP_INIT,"key setup initiated by peer"); |
| 1771 | bool_t entered=enter_new_state(st,SITE_SENTMSG2); |
| 1772 | if (entered && st->addresses && st->local_mobile) |
| 1773 | /* We must do this as the very last thing, because |
| 1774 | the resolver callback might reenter us. */ |
| 1775 | ensure_resolving(st); |
| 1776 | } else { |
| 1777 | slog(st,LOG_ERROR,"failed to process incoming msg1"); |
| 1778 | } |
| 1779 | BUF_FREE(buf); |
| 1780 | return True; |
| 1781 | } else if (st->state==SITE_SENTMSG1) { |
| 1782 | /* We've just sent a message 1! They may have crossed on |
| 1783 | the wire. If we have priority then we ignore the |
| 1784 | incoming one, otherwise we process it as usual. */ |
| 1785 | if (st->setup_priority) { |
| 1786 | BUF_FREE(buf); |
| 1787 | slog(st,LOG_DUMP,"crossed msg1s; we are higher " |
| 1788 | "priority => ignore incoming msg1"); |
| 1789 | return True; |
| 1790 | } else { |
| 1791 | slog(st,LOG_DUMP,"crossed msg1s; we are lower " |
| 1792 | "priority => use incoming msg1"); |
| 1793 | if (process_msg1(st,buf,source,&named_msg)) { |
| 1794 | BUF_FREE(&st->buffer); /* Free our old message 1 */ |
| 1795 | transport_setup_msgok(st,source); |
| 1796 | enter_new_state(st,SITE_SENTMSG2); |
| 1797 | } else { |
| 1798 | slog(st,LOG_ERROR,"failed to process an incoming " |
| 1799 | "crossed msg1 (we have low priority)"); |
| 1800 | } |
| 1801 | BUF_FREE(buf); |
| 1802 | return True; |
| 1803 | } |
| 1804 | } |
| 1805 | /* The message 1 was received at an unexpected stage of the |
| 1806 | key setup. XXX POLICY - what do we do? */ |
| 1807 | slog(st,LOG_UNEXPECTED,"unexpected incoming message 1"); |
| 1808 | BUF_FREE(buf); |
| 1809 | return True; |
| 1810 | } |
| 1811 | if (msgtype==LABEL_PROD) { |
| 1812 | if (!named_for_us(st,buf,msgtype,&named_msg)) |
| 1813 | return False; |
| 1814 | dump_packet(st,buf,source,True,True); |
| 1815 | if (st->state!=SITE_RUN) { |
| 1816 | slog(st,LOG_DROP,"ignoring PROD when not in state RUN"); |
| 1817 | } else if (current_valid(st)) { |
| 1818 | slog(st,LOG_DROP,"ignoring PROD when we think we have a key"); |
| 1819 | } else { |
| 1820 | initiate_key_setup(st,"peer sent PROD packet",source); |
| 1821 | } |
| 1822 | BUF_FREE(buf); |
| 1823 | return True; |
| 1824 | } |
| 1825 | if (dest==st->index) { |
| 1826 | /* Explicitly addressed to us */ |
| 1827 | if (msgtype!=LABEL_MSG0) dump_packet(st,buf,source,True,True); |
| 1828 | switch (msgtype) { |
| 1829 | case LABEL_NAK: |
| 1830 | /* If the source is our current peer then initiate a key setup, |
| 1831 | because our peer's forgotten the key */ |
| 1832 | if (get_uint32(buf->start+4)==st->current.remote_session_id) { |
| 1833 | bool_t initiated; |
| 1834 | initiated = initiate_key_setup(st,"received a NAK",source); |
| 1835 | if (!initiated) generate_send_prod(st,source); |
| 1836 | } else { |
| 1837 | slog(st,LOG_SEC,"bad incoming NAK"); |
| 1838 | } |
| 1839 | break; |
| 1840 | case LABEL_MSG0: |
| 1841 | process_msg0(st,buf,source); |
| 1842 | break; |
| 1843 | case LABEL_MSG1: |
| 1844 | /* Setup packet: should not have been explicitly addressed |
| 1845 | to us */ |
| 1846 | slog(st,LOG_SEC,"incoming explicitly addressed msg1"); |
| 1847 | break; |
| 1848 | case LABEL_MSG2: |
| 1849 | /* Setup packet: expected only in state SENTMSG1 */ |
| 1850 | if (st->state!=SITE_SENTMSG1) { |
| 1851 | slog(st,LOG_UNEXPECTED,"unexpected MSG2"); |
| 1852 | } else if (process_msg2(st,buf,source)) { |
| 1853 | transport_setup_msgok(st,source); |
| 1854 | enter_new_state(st,SITE_SENTMSG3); |
| 1855 | } else { |
| 1856 | slog(st,LOG_SEC,"invalid MSG2"); |
| 1857 | } |
| 1858 | break; |
| 1859 | case LABEL_MSG3: |
| 1860 | case LABEL_MSG3BIS: |
| 1861 | /* Setup packet: expected only in state SENTMSG2 */ |
| 1862 | if (st->state!=SITE_SENTMSG2) { |
| 1863 | slog(st,LOG_UNEXPECTED,"unexpected MSG3"); |
| 1864 | } else if (process_msg3(st,buf,source,msgtype)) { |
| 1865 | transport_setup_msgok(st,source); |
| 1866 | enter_new_state(st,SITE_SENTMSG4); |
| 1867 | } else { |
| 1868 | slog(st,LOG_SEC,"invalid MSG3"); |
| 1869 | } |
| 1870 | break; |
| 1871 | case LABEL_MSG4: |
| 1872 | /* Setup packet: expected only in state SENTMSG3 */ |
| 1873 | if (st->state!=SITE_SENTMSG3) { |
| 1874 | slog(st,LOG_UNEXPECTED,"unexpected MSG4"); |
| 1875 | } else if (process_msg4(st,buf,source)) { |
| 1876 | transport_setup_msgok(st,source); |
| 1877 | enter_new_state(st,SITE_SENTMSG5); |
| 1878 | } else { |
| 1879 | slog(st,LOG_SEC,"invalid MSG4"); |
| 1880 | } |
| 1881 | break; |
| 1882 | case LABEL_MSG5: |
| 1883 | /* Setup packet: expected only in state SENTMSG4 */ |
| 1884 | /* (may turn up in state RUN if our return MSG6 was lost |
| 1885 | and the new key has already been activated. In that |
| 1886 | case we discard it. The peer will realise that we |
| 1887 | are using the new key when they see our data packets. |
| 1888 | Until then the peer's data packets to us get discarded. */ |
| 1889 | if (st->state==SITE_SENTMSG4) { |
| 1890 | if (process_msg5(st,buf,source,st->new_transform)) { |
| 1891 | transport_setup_msgok(st,source); |
| 1892 | enter_new_state(st,SITE_RUN); |
| 1893 | } else { |
| 1894 | slog(st,LOG_SEC,"invalid MSG5"); |
| 1895 | } |
| 1896 | } else if (st->state==SITE_RUN) { |
| 1897 | if (process_msg5(st,buf,source,st->current.transform)) { |
| 1898 | slog(st,LOG_DROP,"got MSG5, retransmitting MSG6"); |
| 1899 | transport_setup_msgok(st,source); |
| 1900 | create_msg6(st,st->current.transform, |
| 1901 | st->current.remote_session_id); |
| 1902 | transport_xmit(st,&st->peers,&st->buffer,True); |
| 1903 | BUF_FREE(&st->buffer); |
| 1904 | } else { |
| 1905 | slog(st,LOG_SEC,"invalid MSG5 (in state RUN)"); |
| 1906 | } |
| 1907 | } else { |
| 1908 | slog(st,LOG_UNEXPECTED,"unexpected MSG5"); |
| 1909 | } |
| 1910 | break; |
| 1911 | case LABEL_MSG6: |
| 1912 | /* Setup packet: expected only in state SENTMSG5 */ |
| 1913 | if (st->state!=SITE_SENTMSG5) { |
| 1914 | slog(st,LOG_UNEXPECTED,"unexpected MSG6"); |
| 1915 | } else if (process_msg6(st,buf,source)) { |
| 1916 | BUF_FREE(&st->buffer); /* Free message 5 */ |
| 1917 | transport_setup_msgok(st,source); |
| 1918 | activate_new_key(st); |
| 1919 | } else { |
| 1920 | slog(st,LOG_SEC,"invalid MSG6"); |
| 1921 | } |
| 1922 | break; |
| 1923 | default: |
| 1924 | slog(st,LOG_SEC,"received message of unknown type 0x%08x", |
| 1925 | msgtype); |
| 1926 | break; |
| 1927 | } |
| 1928 | BUF_FREE(buf); |
| 1929 | return True; |
| 1930 | } |
| 1931 | |
| 1932 | return False; |
| 1933 | } |
| 1934 | |
| 1935 | static void site_control(void *vst, bool_t run) |
| 1936 | { |
| 1937 | struct site *st=vst; |
| 1938 | if (run) enter_state_run(st); |
| 1939 | else enter_state_stop(st); |
| 1940 | } |
| 1941 | |
| 1942 | static void site_phase_hook(void *sst, uint32_t newphase) |
| 1943 | { |
| 1944 | struct site *st=sst; |
| 1945 | |
| 1946 | /* The program is shutting down; tell our peer */ |
| 1947 | send_msg7(st,"shutting down"); |
| 1948 | } |
| 1949 | |
| 1950 | static void site_childpersist_clearkeys(void *sst, uint32_t newphase) |
| 1951 | { |
| 1952 | struct site *st=sst; |
| 1953 | dispose_transform(&st->current.transform); |
| 1954 | dispose_transform(&st->auxiliary_key.transform); |
| 1955 | dispose_transform(&st->new_transform); |
| 1956 | /* Not much point overwiting the signing key, since we loaded it |
| 1957 | from disk, and it is only valid prospectively if at all, |
| 1958 | anyway. */ |
| 1959 | /* XXX it would be best to overwrite the DH state, because that |
| 1960 | _is_ relevant to forward secrecy. However we have no |
| 1961 | convenient interface for doing that and in practice gmp has |
| 1962 | probably dribbled droppings all over the malloc arena. A good |
| 1963 | way to fix this would be to have a privsep child for asymmetric |
| 1964 | crypto operations, but that's a task for another day. */ |
| 1965 | } |
| 1966 | |
| 1967 | static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, |
| 1968 | list_t *args) |
| 1969 | { |
| 1970 | static uint32_t index_sequence; |
| 1971 | struct site *st; |
| 1972 | item_t *item; |
| 1973 | dict_t *dict; |
| 1974 | int i; |
| 1975 | |
| 1976 | NEW(st); |
| 1977 | |
| 1978 | st->cl.description="site"; |
| 1979 | st->cl.type=CL_SITE; |
| 1980 | st->cl.apply=NULL; |
| 1981 | st->cl.interface=&st->ops; |
| 1982 | st->ops.st=st; |
| 1983 | st->ops.control=site_control; |
| 1984 | st->ops.status=site_status; |
| 1985 | |
| 1986 | /* First parameter must be a dict */ |
| 1987 | item=list_elem(args,0); |
| 1988 | if (!item || item->type!=t_dict) |
| 1989 | cfgfatal(loc,"site","parameter must be a dictionary\n"); |
| 1990 | |
| 1991 | dict=item->data.dict; |
| 1992 | st->localname=dict_read_string(dict, "local-name", True, "site", loc); |
| 1993 | st->remotename=dict_read_string(dict, "name", True, "site", loc); |
| 1994 | |
| 1995 | st->keepalive=dict_read_bool(dict,"keepalive",False,"site",loc,False); |
| 1996 | |
| 1997 | st->peer_mobile=dict_read_bool(dict,"mobile",False,"site",loc,False); |
| 1998 | st->local_mobile= |
| 1999 | dict_read_bool(dict,"local-mobile",False,"site",loc,False); |
| 2000 | |
| 2001 | /* Sanity check (which also allows the 'sites' file to include |
| 2002 | site() closures for all sites including our own): refuse to |
| 2003 | talk to ourselves */ |
| 2004 | if (strcmp(st->localname,st->remotename)==0) { |
| 2005 | Message(M_DEBUG,"site %s: local-name==name -> ignoring this site\n", |
| 2006 | st->localname); |
| 2007 | if (st->peer_mobile != st->local_mobile) |
| 2008 | cfgfatal(loc,"site","site %s's peer-mobile=%d" |
| 2009 | " but our local-mobile=%d\n", |
| 2010 | st->localname, st->peer_mobile, st->local_mobile); |
| 2011 | free(st); |
| 2012 | return NULL; |
| 2013 | } |
| 2014 | if (st->peer_mobile && st->local_mobile) { |
| 2015 | Message(M_WARNING,"site %s: site is mobile but so are we" |
| 2016 | " -> ignoring this site\n", st->remotename); |
| 2017 | free(st); |
| 2018 | return NULL; |
| 2019 | } |
| 2020 | |
| 2021 | assert(index_sequence < 0xffffffffUL); |
| 2022 | st->index = ++index_sequence; |
| 2023 | st->local_capabilities = 0; |
| 2024 | st->netlink=find_cl_if(dict,"link",CL_NETLINK,True,"site",loc); |
| 2025 | |
| 2026 | #define GET_CLOSURE_LIST(dictkey,things,nthings,CL_TYPE) do{ \ |
| 2027 | list_t *things##_cfg=dict_lookup(dict,dictkey); \ |
| 2028 | if (!things##_cfg) \ |
| 2029 | cfgfatal(loc,"site","closure list \"%s\" not found\n",dictkey); \ |
| 2030 | st->nthings=list_length(things##_cfg); \ |
| 2031 | NEW_ARY(st->things,st->nthings); \ |
| 2032 | assert(st->nthings); \ |
| 2033 | for (i=0; i<st->nthings; i++) { \ |
| 2034 | item_t *item=list_elem(things##_cfg,i); \ |
| 2035 | if (item->type!=t_closure) \ |
| 2036 | cfgfatal(loc,"site","%s is not a closure\n",dictkey); \ |
| 2037 | closure_t *cl=item->data.closure; \ |
| 2038 | if (cl->type!=CL_TYPE) \ |
| 2039 | cfgfatal(loc,"site","%s closure wrong type\n",dictkey); \ |
| 2040 | st->things[i]=cl->interface; \ |
| 2041 | } \ |
| 2042 | }while(0) |
| 2043 | |
| 2044 | GET_CLOSURE_LIST("comm",comms,ncomms,CL_COMM); |
| 2045 | |
| 2046 | NEW_ARY(st->commclientinfos, st->ncomms); |
| 2047 | dict_t *comminfo = dict_read_dict(dict,"comm-info",False,"site",loc); |
| 2048 | for (i=0; i<st->ncomms; i++) { |
| 2049 | st->commclientinfos[i] = |
| 2050 | !comminfo ? 0 : |
| 2051 | st->comms[i]->clientinfo(st->comms[i],comminfo,loc); |
| 2052 | } |
| 2053 | |
| 2054 | st->resolver=find_cl_if(dict,"resolver",CL_RESOLVER,True,"site",loc); |
| 2055 | st->log=find_cl_if(dict,"log",CL_LOG,True,"site",loc); |
| 2056 | st->random=find_cl_if(dict,"random",CL_RANDOMSRC,True,"site",loc); |
| 2057 | |
| 2058 | st->privkey=find_cl_if(dict,"local-key",CL_RSAPRIVKEY,True,"site",loc); |
| 2059 | st->addresses=dict_read_string_array(dict,"address",False,"site",loc,0); |
| 2060 | if (st->addresses) |
| 2061 | st->remoteport=dict_read_number(dict,"port",True,"site",loc,0); |
| 2062 | else st->remoteport=0; |
| 2063 | st->pubkey=find_cl_if(dict,"key",CL_RSAPUBKEY,True,"site",loc); |
| 2064 | |
| 2065 | GET_CLOSURE_LIST("transform",transforms,ntransforms,CL_TRANSFORM); |
| 2066 | |
| 2067 | st->dh=find_cl_if(dict,"dh",CL_DH,True,"site",loc); |
| 2068 | st->hash=find_cl_if(dict,"hash",CL_HASH,True,"site",loc); |
| 2069 | |
| 2070 | #define DEFAULT(D) (st->peer_mobile || st->local_mobile \ |
| 2071 | ? DEFAULT_MOBILE_##D : DEFAULT_##D) |
| 2072 | #define CFG_NUMBER(k,D) dict_read_number(dict,(k),False,"site",loc,DEFAULT(D)); |
| 2073 | |
| 2074 | st->key_lifetime= CFG_NUMBER("key-lifetime", KEY_LIFETIME); |
| 2075 | st->setup_retries= CFG_NUMBER("setup-retries", SETUP_RETRIES); |
| 2076 | st->setup_retry_interval= CFG_NUMBER("setup-timeout", SETUP_RETRY_INTERVAL); |
| 2077 | st->wait_timeout= CFG_NUMBER("wait-time", WAIT_TIME); |
| 2078 | st->mtu_target= dict_read_number(dict,"mtu-target",False,"site",loc,0); |
| 2079 | |
| 2080 | st->mobile_peer_expiry= dict_read_number( |
| 2081 | dict,"mobile-peer-expiry",False,"site",loc,DEFAULT_MOBILE_PEER_EXPIRY); |
| 2082 | |
| 2083 | const char *peerskey= st->peer_mobile |
| 2084 | ? "mobile-peers-max" : "static-peers-max"; |
| 2085 | st->transport_peers_max= dict_read_number( |
| 2086 | dict,peerskey,False,"site",loc, st->addresses ? 4 : 3); |
| 2087 | if (st->transport_peers_max<1 || |
| 2088 | st->transport_peers_max>MAX_PEER_ADDRS) { |
| 2089 | cfgfatal(loc,"site", "%s must be in range 1.." |
| 2090 | STRING(MAX_PEER_ADDRS) "\n", peerskey); |
| 2091 | } |
| 2092 | |
| 2093 | if (st->key_lifetime < DEFAULT(KEY_RENEGOTIATE_GAP)*2) |
| 2094 | st->key_renegotiate_time=st->key_lifetime/2; |
| 2095 | else |
| 2096 | st->key_renegotiate_time=st->key_lifetime-DEFAULT(KEY_RENEGOTIATE_GAP); |
| 2097 | st->key_renegotiate_time=dict_read_number( |
| 2098 | dict,"renegotiate-time",False,"site",loc,st->key_renegotiate_time); |
| 2099 | if (st->key_renegotiate_time > st->key_lifetime) { |
| 2100 | cfgfatal(loc,"site", |
| 2101 | "renegotiate-time must be less than key-lifetime\n"); |
| 2102 | } |
| 2103 | |
| 2104 | st->log_events=string_list_to_word(dict_lookup(dict,"log-events"), |
| 2105 | log_event_table,"site"); |
| 2106 | |
| 2107 | st->resolving_count=0; |
| 2108 | st->allow_send_prod=0; |
| 2109 | |
| 2110 | st->tunname=safe_malloc(strlen(st->localname)+strlen(st->remotename)+5, |
| 2111 | "site_apply"); |
| 2112 | sprintf(st->tunname,"%s<->%s",st->localname,st->remotename); |
| 2113 | |
| 2114 | /* The information we expect to see in incoming messages of type 1 */ |
| 2115 | /* fixme: lots of unchecked overflows here, but the results are only |
| 2116 | corrupted packets rather than undefined behaviour */ |
| 2117 | st->setup_priority=(strcmp(st->localname,st->remotename)>0); |
| 2118 | |
| 2119 | buffer_new(&st->buffer,SETUP_BUFFER_LEN); |
| 2120 | |
| 2121 | buffer_new(&st->scratch,SETUP_BUFFER_LEN); |
| 2122 | BUF_ALLOC(&st->scratch,"site:scratch"); |
| 2123 | |
| 2124 | /* We are interested in poll(), but only for timeouts. We don't have |
| 2125 | any fds of our own. */ |
| 2126 | register_for_poll(st, site_beforepoll, site_afterpoll, "site"); |
| 2127 | st->timeout=0; |
| 2128 | |
| 2129 | st->remote_capabilities=0; |
| 2130 | st->chosen_transform=0; |
| 2131 | st->current.key_timeout=0; |
| 2132 | st->auxiliary_key.key_timeout=0; |
| 2133 | transport_peers_clear(st,&st->peers); |
| 2134 | transport_peers_clear(st,&st->setup_peers); |
| 2135 | /* XXX mlock these */ |
| 2136 | st->dhsecret=safe_malloc(st->dh->len,"site:dhsecret"); |
| 2137 | st->sharedsecretlen=st->sharedsecretallocd=0; |
| 2138 | st->sharedsecret=0; |
| 2139 | |
| 2140 | for (i=0; i<st->ntransforms; i++) { |
| 2141 | struct transform_if *ti=st->transforms[i]; |
| 2142 | uint32_t capbit = 1UL << ti->capab_transformnum; |
| 2143 | if (st->local_capabilities & capbit) |
| 2144 | slog(st,LOG_ERROR,"transformnum capability bit" |
| 2145 | " %d (%#"PRIx32") reused", ti->capab_transformnum, capbit); |
| 2146 | st->local_capabilities |= capbit; |
| 2147 | } |
| 2148 | |
| 2149 | /* We need to register the remote networks with the netlink device */ |
| 2150 | uint32_t netlink_mtu; /* local virtual interface mtu */ |
| 2151 | st->netlink->reg(st->netlink->st, site_outgoing, st, &netlink_mtu); |
| 2152 | if (!st->mtu_target) |
| 2153 | st->mtu_target=netlink_mtu; |
| 2154 | |
| 2155 | for (i=0; i<st->ncomms; i++) |
| 2156 | st->comms[i]->request_notify(st->comms[i]->st, st, site_incoming); |
| 2157 | |
| 2158 | st->current.transform=0; |
| 2159 | st->auxiliary_key.transform=0; |
| 2160 | st->new_transform=0; |
| 2161 | st->auxiliary_is_new=0; |
| 2162 | |
| 2163 | enter_state_stop(st); |
| 2164 | |
| 2165 | add_hook(PHASE_SHUTDOWN,site_phase_hook,st); |
| 2166 | add_hook(PHASE_CHILDPERSIST,site_childpersist_clearkeys,st); |
| 2167 | |
| 2168 | return new_closure(&st->cl); |
| 2169 | } |
| 2170 | |
| 2171 | void site_module(dict_t *dict) |
| 2172 | { |
| 2173 | add_closure(dict,"site",site_apply); |
| 2174 | } |
| 2175 | |
| 2176 | |
| 2177 | /***** TRANSPORT PEERS definitions *****/ |
| 2178 | |
| 2179 | static void transport_peers_debug(struct site *st, transport_peers *dst, |
| 2180 | const char *didwhat, |
| 2181 | int nargs, const struct comm_addr *args, |
| 2182 | size_t stride) { |
| 2183 | int i; |
| 2184 | char *argp; |
| 2185 | |
| 2186 | if (!(st->log_events & LOG_PEER_ADDRS)) |
| 2187 | return; /* an optimisation */ |
| 2188 | |
| 2189 | slog(st, LOG_PEER_ADDRS, "peers (%s) %s nargs=%d => npeers=%d", |
| 2190 | (dst==&st->peers ? "data" : |
| 2191 | dst==&st->setup_peers ? "setup" : "UNKNOWN"), |
| 2192 | didwhat, nargs, dst->npeers); |
| 2193 | |
| 2194 | for (i=0, argp=(void*)args; |
| 2195 | i<nargs; |
| 2196 | i++, (argp+=stride?stride:sizeof(*args))) { |
| 2197 | const struct comm_addr *ca=(void*)argp; |
| 2198 | slog(st, LOG_PEER_ADDRS, " args: addrs[%d]=%s", |
| 2199 | i, comm_addr_to_string(ca)); |
| 2200 | } |
| 2201 | for (i=0; i<dst->npeers; i++) { |
| 2202 | struct timeval diff; |
| 2203 | timersub(tv_now,&dst->peers[i].last,&diff); |
| 2204 | const struct comm_addr *ca=&dst->peers[i].addr; |
| 2205 | slog(st, LOG_PEER_ADDRS, " peers: addrs[%d]=%s T-%ld.%06ld", |
| 2206 | i, comm_addr_to_string(ca), |
| 2207 | (unsigned long)diff.tv_sec, (unsigned long)diff.tv_usec); |
| 2208 | } |
| 2209 | } |
| 2210 | |
| 2211 | static void transport_peers_expire(struct site *st, transport_peers *peers) { |
| 2212 | /* peers must be sorted first */ |
| 2213 | int previous_peers=peers->npeers; |
| 2214 | struct timeval oldest; |
| 2215 | oldest.tv_sec = tv_now->tv_sec - st->mobile_peer_expiry; |
| 2216 | oldest.tv_usec = tv_now->tv_usec; |
| 2217 | while (peers->npeers>1 && |
| 2218 | timercmp(&peers->peers[peers->npeers-1].last, &oldest, <)) |
| 2219 | peers->npeers--; |
| 2220 | if (peers->npeers != previous_peers) |
| 2221 | transport_peers_debug(st,peers,"expire", 0,0,0); |
| 2222 | } |
| 2223 | |
| 2224 | static bool_t transport_peer_record_one(struct site *st, transport_peers *peers, |
| 2225 | const struct comm_addr *ca, |
| 2226 | const struct timeval *tv) { |
| 2227 | /* returns false if output is full */ |
| 2228 | int search; |
| 2229 | |
| 2230 | if (peers->npeers >= st->transport_peers_max) |
| 2231 | return 0; |
| 2232 | |
| 2233 | for (search=0; search<peers->npeers; search++) |
| 2234 | if (comm_addr_equal(&peers->peers[search].addr, ca)) |
| 2235 | return 1; |
| 2236 | |
| 2237 | peers->peers[peers->npeers].addr = *ca; |
| 2238 | peers->peers[peers->npeers].last = *tv; |
| 2239 | peers->npeers++; |
| 2240 | return 1; |
| 2241 | } |
| 2242 | |
| 2243 | static void transport_record_peers(struct site *st, transport_peers *peers, |
| 2244 | const struct comm_addr *addrs, int naddrs, |
| 2245 | const char *m) { |
| 2246 | /* We add addrs into peers. The new entries end up at the front |
| 2247 | * and displace entries towards the end (perhaps even off the |
| 2248 | * end). Any existing matching entries are moved up to the front. |
| 2249 | * |
| 2250 | * Caller must first call transport_peers_expire. */ |
| 2251 | |
| 2252 | if (naddrs==1 && peers->npeers>=1 && |
| 2253 | comm_addr_equal(&addrs[0], &peers->peers[0].addr)) { |
| 2254 | /* optimisation, also avoids debug for trivial updates */ |
| 2255 | peers->peers[0].last = *tv_now; |
| 2256 | return; |
| 2257 | } |
| 2258 | |
| 2259 | int old_npeers=peers->npeers; |
| 2260 | transport_peer old_peers[old_npeers]; |
| 2261 | COPY_ARRAY(old_peers,peers->peers,old_npeers); |
| 2262 | |
| 2263 | peers->npeers=0; |
| 2264 | int i; |
| 2265 | for (i=0; i<naddrs; i++) { |
| 2266 | if (!transport_peer_record_one(st,peers, &addrs[i], tv_now)) |
| 2267 | break; |
| 2268 | } |
| 2269 | for (i=0; i<old_npeers; i++) { |
| 2270 | const transport_peer *old=&old_peers[i]; |
| 2271 | if (!transport_peer_record_one(st,peers, &old->addr, &old->last)) |
| 2272 | break; |
| 2273 | } |
| 2274 | |
| 2275 | transport_peers_debug(st,peers,m, naddrs,addrs,0); |
| 2276 | } |
| 2277 | |
| 2278 | static void transport_expire_record_peers(struct site *st, |
| 2279 | transport_peers *peers, |
| 2280 | const struct comm_addr *addrs, |
| 2281 | int naddrs, const char *m) { |
| 2282 | /* Convenience function */ |
| 2283 | transport_peers_expire(st,peers); |
| 2284 | transport_record_peers(st,peers,addrs,naddrs,m); |
| 2285 | } |
| 2286 | |
| 2287 | static bool_t transport_compute_setupinit_peers(struct site *st, |
| 2288 | const struct comm_addr *configured_addrs /* 0 if none or not found */, |
| 2289 | int n_configured_addrs /* 0 if none or not found */, |
| 2290 | const struct comm_addr *incoming_packet_addr /* 0 if none */) { |
| 2291 | if (!n_configured_addrs && !incoming_packet_addr && |
| 2292 | !transport_peers_valid(&st->peers)) |
| 2293 | return False; |
| 2294 | |
| 2295 | slog(st,LOG_SETUP_INIT, |
| 2296 | "using: %d configured addr(s);%s %d old peer addrs(es)", |
| 2297 | n_configured_addrs, |
| 2298 | incoming_packet_addr ? " incoming packet address;" : "", |
| 2299 | st->peers.npeers); |
| 2300 | |
| 2301 | /* Non-mobile peers try addresses until one is plausible. The |
| 2302 | * effect is that this code always tries first the configured |
| 2303 | * address if supplied, or otherwise the address of the incoming |
| 2304 | * PROD, or finally the existing data peer if one exists; this is |
| 2305 | * as desired. */ |
| 2306 | |
| 2307 | transport_peers_copy(st,&st->setup_peers,&st->peers); |
| 2308 | transport_peers_expire(st,&st->setup_peers); |
| 2309 | |
| 2310 | if (incoming_packet_addr) |
| 2311 | transport_record_peers(st,&st->setup_peers, |
| 2312 | incoming_packet_addr,1, "incoming"); |
| 2313 | |
| 2314 | if (n_configured_addrs) |
| 2315 | transport_record_peers(st,&st->setup_peers, |
| 2316 | configured_addrs,n_configured_addrs, "setupinit"); |
| 2317 | |
| 2318 | assert(transport_peers_valid(&st->setup_peers)); |
| 2319 | return True; |
| 2320 | } |
| 2321 | |
| 2322 | static void transport_setup_msgok(struct site *st, const struct comm_addr *a) { |
| 2323 | if (st->peer_mobile) |
| 2324 | transport_expire_record_peers(st,&st->setup_peers,a,1,"setupmsg"); |
| 2325 | } |
| 2326 | static void transport_data_msgok(struct site *st, const struct comm_addr *a) { |
| 2327 | if (st->peer_mobile) |
| 2328 | transport_expire_record_peers(st,&st->peers,a,1,"datamsg"); |
| 2329 | } |
| 2330 | |
| 2331 | static int transport_peers_valid(transport_peers *peers) { |
| 2332 | return peers->npeers; |
| 2333 | } |
| 2334 | static void transport_peers_clear(struct site *st, transport_peers *peers) { |
| 2335 | peers->npeers= 0; |
| 2336 | transport_peers_debug(st,peers,"clear",0,0,0); |
| 2337 | } |
| 2338 | static void transport_peers_copy(struct site *st, transport_peers *dst, |
| 2339 | const transport_peers *src) { |
| 2340 | dst->npeers=src->npeers; |
| 2341 | COPY_ARRAY(dst->peers, src->peers, dst->npeers); |
| 2342 | transport_peers_debug(st,dst,"copy", |
| 2343 | src->npeers, &src->peers->addr, sizeof(*src->peers)); |
| 2344 | } |
| 2345 | |
| 2346 | static void transport_resolve_complete(struct site *st, |
| 2347 | const struct comm_addr *addrs, |
| 2348 | int naddrs) { |
| 2349 | transport_expire_record_peers(st,&st->peers,addrs,naddrs, |
| 2350 | "resolved data"); |
| 2351 | transport_expire_record_peers(st,&st->setup_peers,addrs,naddrs, |
| 2352 | "resolved setup"); |
| 2353 | } |
| 2354 | |
| 2355 | static void transport_resolve_complete_tardy(struct site *st, |
| 2356 | const struct comm_addr *addrs, |
| 2357 | int naddrs) { |
| 2358 | transport_expire_record_peers(st,&st->peers,addrs,naddrs, |
| 2359 | "resolved tardily"); |
| 2360 | } |
| 2361 | |
| 2362 | static void transport_peers__copy_by_mask(transport_peer *out, int *nout_io, |
| 2363 | unsigned mask, |
| 2364 | const transport_peers *inp) { |
| 2365 | /* out and in->peers may be the same region, or nonoverlapping */ |
| 2366 | const transport_peer *in=inp->peers; |
| 2367 | int slot; |
| 2368 | for (slot=0; slot<inp->npeers; slot++) { |
| 2369 | if (!(mask & (1U << slot))) |
| 2370 | continue; |
| 2371 | if (!(out==in && slot==*nout_io)) |
| 2372 | COPY_OBJ(out[*nout_io], in[slot]); |
| 2373 | (*nout_io)++; |
| 2374 | } |
| 2375 | } |
| 2376 | |
| 2377 | void transport_xmit(struct site *st, transport_peers *peers, |
| 2378 | struct buffer_if *buf, bool_t candebug) { |
| 2379 | int slot; |
| 2380 | transport_peers_expire(st, peers); |
| 2381 | unsigned failed=0; /* bitmask */ |
| 2382 | assert(MAX_PEER_ADDRS < sizeof(unsigned)*CHAR_BIT); |
| 2383 | |
| 2384 | int nfailed=0; |
| 2385 | for (slot=0; slot<peers->npeers; slot++) { |
| 2386 | transport_peer *peer=&peers->peers[slot]; |
| 2387 | bool_t ok = comm_addr_sendmsg(st, &peer->addr, buf); |
| 2388 | if (candebug) |
| 2389 | dump_packet(st, buf, &peer->addr, False, ok); |
| 2390 | if (!ok) { |
| 2391 | failed |= 1U << slot; |
| 2392 | nfailed++; |
| 2393 | } |
| 2394 | if (ok && !st->peer_mobile) |
| 2395 | break; |
| 2396 | } |
| 2397 | /* Now we need to demote/delete failing addrs: if we are mobile we |
| 2398 | * merely demote them; otherwise we delete them. */ |
| 2399 | if (st->local_mobile) { |
| 2400 | unsigned expected = ((1U << nfailed)-1) << (peers->npeers-nfailed); |
| 2401 | /* `expected' has all the failures at the end already */ |
| 2402 | if (failed != expected) { |
| 2403 | int fslot=0; |
| 2404 | transport_peer failedpeers[nfailed]; |
| 2405 | transport_peers__copy_by_mask(failedpeers, &fslot, failed,peers); |
| 2406 | assert(fslot == nfailed); |
| 2407 | int wslot=0; |
| 2408 | transport_peers__copy_by_mask(peers->peers,&wslot,~failed,peers); |
| 2409 | assert(wslot+nfailed == peers->npeers); |
| 2410 | COPY_ARRAY(peers->peers+wslot, failedpeers, nfailed); |
| 2411 | transport_peers_debug(st,peers,"mobile failure reorder",0,0,0); |
| 2412 | } |
| 2413 | } else { |
| 2414 | if (failed && peers->npeers > 1) { |
| 2415 | int wslot=0; |
| 2416 | transport_peers__copy_by_mask(peers->peers,&wslot,~failed,peers); |
| 2417 | peers->npeers=wslot; |
| 2418 | transport_peers_debug(st,peers,"non-mobile failure cleanup",0,0,0); |
| 2419 | } |
| 2420 | } |
| 2421 | } |
| 2422 | |
| 2423 | /***** END of transport peers declarations *****/ |