| 1 | /* site.c - manage communication with a remote network site */ |
| 2 | |
| 3 | /* The 'site' code doesn't know anything about the structure of the |
| 4 | packets it's transmitting. In fact, under the new netlink |
| 5 | configuration scheme it doesn't need to know anything at all about |
| 6 | IP addresses, except how to contact its peer. This means it could |
| 7 | potentially be used to tunnel other protocols too (IPv6, IPX, plain |
| 8 | old Ethernet frames) if appropriate netlink code can be written |
| 9 | (and that ought not to be too hard, eg. using the TUN/TAP device to |
| 10 | pretend to be an Ethernet interface). */ |
| 11 | |
| 12 | /* At some point in the future the netlink code will be asked for |
| 13 | configuration information to go in the PING/PONG packets at the end |
| 14 | of the key exchange. */ |
| 15 | |
| 16 | #include "secnet.h" |
| 17 | #include <stdio.h> |
| 18 | #include <string.h> |
| 19 | #include <limits.h> |
| 20 | #include <sys/socket.h> |
| 21 | |
| 22 | #include <sys/mman.h> |
| 23 | #include "util.h" |
| 24 | #include "unaligned.h" |
| 25 | #include "magic.h" |
| 26 | |
| 27 | #define SETUP_BUFFER_LEN 2048 |
| 28 | |
| 29 | #define DEFAULT_KEY_LIFETIME 3600000 /* One hour */ |
| 30 | #define DEFAULT_KEY_RENEGOTIATE_GAP 300000 /* Five minutes */ |
| 31 | #define DEFAULT_SETUP_RETRIES 5 |
| 32 | #define DEFAULT_SETUP_TIMEOUT 2000 |
| 33 | #define DEFAULT_WAIT_TIME 20000 |
| 34 | |
| 35 | /* Each site can be in one of several possible states. */ |
| 36 | |
| 37 | /* States: |
| 38 | SITE_STOP - nothing is allowed to happen; tunnel is down; |
| 39 | all session keys have been erased |
| 40 | -> SITE_RUN upon external instruction |
| 41 | SITE_RUN - site up, maybe with valid key |
| 42 | -> SITE_RESOLVE upon outgoing packet and no valid key |
| 43 | we start name resolution for the other end of the tunnel |
| 44 | -> SITE_SENTMSG2 upon valid incoming message 1 and suitable time |
| 45 | we send an appropriate message 2 |
| 46 | SITE_RESOLVE - waiting for name resolution |
| 47 | -> SITE_SENTMSG1 upon successful resolution |
| 48 | we send an appropriate message 1 |
| 49 | -> SITE_SENTMSG2 upon valid incoming message 1 (then abort resolution) |
| 50 | we abort resolution and |
| 51 | -> SITE_WAIT on timeout or resolution failure |
| 52 | SITE_SENTMSG1 |
| 53 | -> SITE_SENTMSG2 upon valid incoming message 1 from higher priority end |
| 54 | -> SITE_SENTMSG3 upon valid incoming message 2 |
| 55 | -> SITE_WAIT on timeout |
| 56 | SITE_SENTMSG2 |
| 57 | -> SITE_SENTMSG4 upon valid incoming message 3 |
| 58 | -> SITE_WAIT on timeout |
| 59 | SITE_SENTMSG3 |
| 60 | -> SITE_SENTMSG5 upon valid incoming message 4 |
| 61 | -> SITE_WAIT on timeout |
| 62 | SITE_SENTMSG4 |
| 63 | -> SITE_RUN upon valid incoming message 5 |
| 64 | -> SITE_WAIT on timeout |
| 65 | SITE_SENTMSG5 |
| 66 | -> SITE_RUN upon valid incoming message 6 |
| 67 | -> SITE_WAIT on timeout |
| 68 | SITE_WAIT - failed to establish key; do nothing for a while |
| 69 | -> SITE_RUN on timeout |
| 70 | */ |
| 71 | |
| 72 | #define SITE_STOP 0 |
| 73 | #define SITE_RUN 1 |
| 74 | #define SITE_RESOLVE 2 |
| 75 | #define SITE_SENTMSG1 3 |
| 76 | #define SITE_SENTMSG2 4 |
| 77 | #define SITE_SENTMSG3 5 |
| 78 | #define SITE_SENTMSG4 6 |
| 79 | #define SITE_SENTMSG5 7 |
| 80 | #define SITE_WAIT 8 |
| 81 | |
| 82 | static cstring_t state_name(uint32_t state) |
| 83 | { |
| 84 | switch (state) { |
| 85 | case 0: return "STOP"; |
| 86 | case 1: return "RUN"; |
| 87 | case 2: return "RESOLVE"; |
| 88 | case 3: return "SENTMSG1"; |
| 89 | case 4: return "SENTMSG2"; |
| 90 | case 5: return "SENTMSG3"; |
| 91 | case 6: return "SENTMSG4"; |
| 92 | case 7: return "SENTMSG5"; |
| 93 | case 8: return "WAIT"; |
| 94 | default: return "*bad state*"; |
| 95 | } |
| 96 | } |
| 97 | |
| 98 | #define NONCELEN 8 |
| 99 | |
| 100 | #define LOG_UNEXPECTED 0x00000001 |
| 101 | #define LOG_SETUP_INIT 0x00000002 |
| 102 | #define LOG_SETUP_TIMEOUT 0x00000004 |
| 103 | #define LOG_ACTIVATE_KEY 0x00000008 |
| 104 | #define LOG_TIMEOUT_KEY 0x00000010 |
| 105 | #define LOG_SEC 0x00000020 |
| 106 | #define LOG_STATE 0x00000040 |
| 107 | #define LOG_DROP 0x00000080 |
| 108 | #define LOG_DUMP 0x00000100 |
| 109 | #define LOG_ERROR 0x00000400 |
| 110 | |
| 111 | static struct flagstr log_event_table[]={ |
| 112 | { "unexpected", LOG_UNEXPECTED }, |
| 113 | { "setup-init", LOG_SETUP_INIT }, |
| 114 | { "setup-timeout", LOG_SETUP_TIMEOUT }, |
| 115 | { "activate-key", LOG_ACTIVATE_KEY }, |
| 116 | { "timeout-key", LOG_TIMEOUT_KEY }, |
| 117 | { "security", LOG_SEC }, |
| 118 | { "state-change", LOG_STATE }, |
| 119 | { "packet-drop", LOG_DROP }, |
| 120 | { "dump-packets", LOG_DUMP }, |
| 121 | { "errors", LOG_ERROR }, |
| 122 | { "default", LOG_SETUP_INIT|LOG_SETUP_TIMEOUT| |
| 123 | LOG_ACTIVATE_KEY|LOG_TIMEOUT_KEY|LOG_SEC|LOG_ERROR }, |
| 124 | { "all", 0xffffffff }, |
| 125 | { NULL, 0 } |
| 126 | }; |
| 127 | |
| 128 | struct site { |
| 129 | closure_t cl; |
| 130 | struct site_if ops; |
| 131 | /* configuration information */ |
| 132 | string_t localname; |
| 133 | string_t remotename; |
| 134 | string_t tunname; /* localname<->remotename by default, used in logs */ |
| 135 | string_t address; /* DNS name for bootstrapping, optional */ |
| 136 | int remoteport; /* Port for bootstrapping, optional */ |
| 137 | struct netlink_if *netlink; |
| 138 | struct comm_if *comm; |
| 139 | struct resolver_if *resolver; |
| 140 | struct log_if *log; |
| 141 | struct random_if *random; |
| 142 | struct rsaprivkey_if *privkey; |
| 143 | struct rsapubkey_if *pubkey; |
| 144 | struct transform_if *transform; |
| 145 | struct dh_if *dh; |
| 146 | struct hash_if *hash; |
| 147 | |
| 148 | int32_t setup_retries; /* How many times to send setup packets */ |
| 149 | int32_t setup_timeout; /* Initial timeout for setup packets */ |
| 150 | int32_t wait_timeout; /* How long to wait if setup unsuccessful */ |
| 151 | int32_t key_lifetime; /* How long a key lasts once set up */ |
| 152 | int32_t key_renegotiate_time; /* If we see traffic (or a keepalive) |
| 153 | after this time, initiate a new |
| 154 | key exchange */ |
| 155 | bool_t keepalive; /* Send keepalives to detect peer failure (not yet |
| 156 | implemented) */ |
| 157 | |
| 158 | uint8_t *setupsig; /* Expected signature of incoming MSG1 packets */ |
| 159 | int32_t setupsiglen; /* Allows us to discard packets quickly if |
| 160 | they are not for us */ |
| 161 | bool_t setup_priority; /* Do we have precedence if both sites emit |
| 162 | message 1 simultaneously? */ |
| 163 | uint32_t log_events; |
| 164 | |
| 165 | /* runtime information */ |
| 166 | uint32_t state; |
| 167 | uint64_t now; /* Most recently seen time */ |
| 168 | |
| 169 | /* The currently established session */ |
| 170 | uint32_t remote_session_id; |
| 171 | struct transform_inst_if *current_transform; |
| 172 | bool_t current_valid; |
| 173 | uint64_t current_key_timeout; /* End of life of current key */ |
| 174 | uint64_t renegotiate_key_time; /* When we can negotiate a new key */ |
| 175 | struct sockaddr_in peer; /* Current address of peer */ |
| 176 | bool_t peer_valid; /* Peer address becomes invalid when key times out, |
| 177 | but only if we have a DNS name for our peer */ |
| 178 | |
| 179 | /* The current key setup protocol exchange. We can only be |
| 180 | involved in one of these at a time. There's a potential for |
| 181 | denial of service here (the attacker keeps sending a setup |
| 182 | packet; we keep trying to continue the exchange, and have to |
| 183 | timeout before we can listen for another setup packet); perhaps |
| 184 | we should keep a list of 'bad' sources for setup packets. */ |
| 185 | uint32_t setup_session_id; |
| 186 | struct sockaddr_in setup_peer; |
| 187 | uint8_t localN[NONCELEN]; /* Nonces for key exchange */ |
| 188 | uint8_t remoteN[NONCELEN]; |
| 189 | struct buffer_if buffer; /* Current outgoing key exchange packet */ |
| 190 | int32_t retries; /* Number of retries remaining */ |
| 191 | uint64_t timeout; /* Timeout for current state */ |
| 192 | uint8_t *dhsecret; |
| 193 | uint8_t *sharedsecret; |
| 194 | struct transform_inst_if *new_transform; /* For key setup/verify */ |
| 195 | }; |
| 196 | |
| 197 | static void slog(struct site *st, uint32_t event, cstring_t msg, ...) |
| 198 | { |
| 199 | va_list ap; |
| 200 | char buf[240]; |
| 201 | uint32_t class; |
| 202 | |
| 203 | va_start(ap,msg); |
| 204 | |
| 205 | if (event&st->log_events) { |
| 206 | switch(event) { |
| 207 | case LOG_UNEXPECTED: class=M_INFO; break; |
| 208 | case LOG_SETUP_INIT: class=M_INFO; break; |
| 209 | case LOG_SETUP_TIMEOUT: class=M_NOTICE; break; |
| 210 | case LOG_ACTIVATE_KEY: class=M_INFO; break; |
| 211 | case LOG_TIMEOUT_KEY: class=M_INFO; break; |
| 212 | case LOG_SEC: class=M_SECURITY; break; |
| 213 | case LOG_STATE: class=M_DEBUG; break; |
| 214 | case LOG_DROP: class=M_DEBUG; break; |
| 215 | case LOG_DUMP: class=M_DEBUG; break; |
| 216 | case LOG_ERROR: class=M_ERR; break; |
| 217 | default: class=M_ERR; break; |
| 218 | } |
| 219 | |
| 220 | vsnprintf(buf,240,msg,ap); |
| 221 | st->log->log(st->log->st,class,"%s: %s",st->tunname,buf); |
| 222 | } |
| 223 | va_end(ap); |
| 224 | } |
| 225 | |
| 226 | static void set_link_quality(struct site *st); |
| 227 | static void delete_key(struct site *st, cstring_t reason, uint32_t loglevel); |
| 228 | static bool_t initiate_key_setup(struct site *st, cstring_t reason); |
| 229 | static void enter_state_run(struct site *st); |
| 230 | static bool_t enter_state_resolve(struct site *st); |
| 231 | static bool_t enter_new_state(struct site *st,uint32_t next); |
| 232 | static void enter_state_wait(struct site *st); |
| 233 | |
| 234 | #define CHECK_AVAIL(b,l) do { if ((b)->size<(l)) return False; } while(0) |
| 235 | #define CHECK_EMPTY(b) do { if ((b)->size!=0) return False; } while(0) |
| 236 | #define CHECK_TYPE(b,t) do { uint32_t type; \ |
| 237 | CHECK_AVAIL((b),4); \ |
| 238 | type=buf_unprepend_uint32((b)); \ |
| 239 | if (type!=(t)) return False; } while(0) |
| 240 | |
| 241 | struct msg { |
| 242 | uint8_t *hashstart; |
| 243 | uint32_t dest; |
| 244 | uint32_t source; |
| 245 | int32_t remlen; |
| 246 | uint8_t *remote; |
| 247 | int32_t loclen; |
| 248 | uint8_t *local; |
| 249 | uint8_t *nR; |
| 250 | uint8_t *nL; |
| 251 | int32_t pklen; |
| 252 | uint8_t *pk; |
| 253 | int32_t hashlen; |
| 254 | int32_t siglen; |
| 255 | uint8_t *sig; |
| 256 | }; |
| 257 | |
| 258 | /* Build any of msg1 to msg4. msg5 and msg6 are built from the inside |
| 259 | out using a transform of config data supplied by netlink */ |
| 260 | static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what) |
| 261 | { |
| 262 | void *hst; |
| 263 | uint8_t *hash; |
| 264 | string_t dhpub, sig; |
| 265 | |
| 266 | st->retries=st->setup_retries; |
| 267 | BUF_ALLOC(&st->buffer,what); |
| 268 | buffer_init(&st->buffer,0); |
| 269 | buf_append_uint32(&st->buffer, |
| 270 | (type==LABEL_MSG1?0:st->setup_session_id)); |
| 271 | buf_append_uint32(&st->buffer,(uint32_t)st); |
| 272 | buf_append_uint32(&st->buffer,type); |
| 273 | buf_append_string(&st->buffer,st->localname); |
| 274 | buf_append_string(&st->buffer,st->remotename); |
| 275 | memcpy(buf_append(&st->buffer,NONCELEN),st->localN,NONCELEN); |
| 276 | if (type==LABEL_MSG1) return True; |
| 277 | memcpy(buf_append(&st->buffer,NONCELEN),st->remoteN,NONCELEN); |
| 278 | if (type==LABEL_MSG2) return True; |
| 279 | |
| 280 | if (hacky_par_mid_failnow()) return False; |
| 281 | |
| 282 | dhpub=st->dh->makepublic(st->dh->st,st->dhsecret,st->dh->len); |
| 283 | buf_append_string(&st->buffer,dhpub); |
| 284 | free(dhpub); |
| 285 | hash=safe_malloc(st->hash->len, "generate_msg"); |
| 286 | hst=st->hash->init(); |
| 287 | st->hash->update(hst,st->buffer.start,st->buffer.size); |
| 288 | st->hash->final(hst,hash); |
| 289 | sig=st->privkey->sign(st->privkey->st,hash,st->hash->len); |
| 290 | buf_append_string(&st->buffer,sig); |
| 291 | free(sig); |
| 292 | free(hash); |
| 293 | return True; |
| 294 | } |
| 295 | |
| 296 | static bool_t unpick_msg(struct site *st, uint32_t type, |
| 297 | struct buffer_if *msg, struct msg *m) |
| 298 | { |
| 299 | m->hashstart=msg->start; |
| 300 | CHECK_AVAIL(msg,4); |
| 301 | m->dest=buf_unprepend_uint32(msg); |
| 302 | CHECK_AVAIL(msg,4); |
| 303 | m->source=buf_unprepend_uint32(msg); |
| 304 | CHECK_TYPE(msg,type); |
| 305 | CHECK_AVAIL(msg,2); |
| 306 | m->remlen=buf_unprepend_uint16(msg); |
| 307 | CHECK_AVAIL(msg,m->remlen); |
| 308 | m->remote=buf_unprepend(msg,m->remlen); |
| 309 | CHECK_AVAIL(msg,2); |
| 310 | m->loclen=buf_unprepend_uint16(msg); |
| 311 | CHECK_AVAIL(msg,m->loclen); |
| 312 | m->local=buf_unprepend(msg,m->loclen); |
| 313 | CHECK_AVAIL(msg,NONCELEN); |
| 314 | m->nR=buf_unprepend(msg,NONCELEN); |
| 315 | if (type==LABEL_MSG1) { |
| 316 | CHECK_EMPTY(msg); |
| 317 | return True; |
| 318 | } |
| 319 | CHECK_AVAIL(msg,NONCELEN); |
| 320 | m->nL=buf_unprepend(msg,NONCELEN); |
| 321 | if (type==LABEL_MSG2) { |
| 322 | CHECK_EMPTY(msg); |
| 323 | return True; |
| 324 | } |
| 325 | CHECK_AVAIL(msg,2); |
| 326 | m->pklen=buf_unprepend_uint16(msg); |
| 327 | CHECK_AVAIL(msg,m->pklen); |
| 328 | m->pk=buf_unprepend(msg,m->pklen); |
| 329 | m->hashlen=msg->start-m->hashstart; |
| 330 | CHECK_AVAIL(msg,2); |
| 331 | m->siglen=buf_unprepend_uint16(msg); |
| 332 | CHECK_AVAIL(msg,m->siglen); |
| 333 | m->sig=buf_unprepend(msg,m->siglen); |
| 334 | CHECK_EMPTY(msg); |
| 335 | return True; |
| 336 | } |
| 337 | |
| 338 | static bool_t check_msg(struct site *st, uint32_t type, struct msg *m, |
| 339 | cstring_t *error) |
| 340 | { |
| 341 | if (type==LABEL_MSG1) return True; |
| 342 | |
| 343 | /* Check that the site names and our nonce have been sent |
| 344 | back correctly, and then store our peer's nonce. */ |
| 345 | if (memcmp(m->remote,st->remotename,strlen(st->remotename)!=0)) { |
| 346 | *error="wrong remote site name"; |
| 347 | return False; |
| 348 | } |
| 349 | if (memcmp(m->local,st->localname,strlen(st->localname)!=0)) { |
| 350 | *error="wrong local site name"; |
| 351 | return False; |
| 352 | } |
| 353 | if (memcmp(m->nL,st->localN,NONCELEN)!=0) { |
| 354 | *error="wrong locally-generated nonce"; |
| 355 | return False; |
| 356 | } |
| 357 | if (type==LABEL_MSG2) return True; |
| 358 | if (memcmp(m->nR,st->remoteN,NONCELEN)!=0) { |
| 359 | *error="wrong remotely-generated nonce"; |
| 360 | return False; |
| 361 | } |
| 362 | if (type==LABEL_MSG3) return True; |
| 363 | if (type==LABEL_MSG4) return True; |
| 364 | *error="unknown message type"; |
| 365 | return False; |
| 366 | } |
| 367 | |
| 368 | static bool_t generate_msg1(struct site *st) |
| 369 | { |
| 370 | st->random->generate(st->random->st,NONCELEN,st->localN); |
| 371 | return generate_msg(st,LABEL_MSG1,"site:MSG1"); |
| 372 | } |
| 373 | |
| 374 | static bool_t process_msg1(struct site *st, struct buffer_if *msg1, |
| 375 | struct sockaddr_in *src) |
| 376 | { |
| 377 | struct msg m; |
| 378 | |
| 379 | /* We've already determined we're in an appropriate state to |
| 380 | process an incoming MSG1, and that the MSG1 has correct values |
| 381 | of A and B. */ |
| 382 | |
| 383 | if (!unpick_msg(st,LABEL_MSG1,msg1,&m)) return False; |
| 384 | |
| 385 | st->setup_peer=*src; |
| 386 | st->setup_session_id=m.source; |
| 387 | memcpy(st->remoteN,m.nR,NONCELEN); |
| 388 | return True; |
| 389 | } |
| 390 | |
| 391 | static bool_t generate_msg2(struct site *st) |
| 392 | { |
| 393 | st->random->generate(st->random->st,NONCELEN,st->localN); |
| 394 | return generate_msg(st,LABEL_MSG2,"site:MSG2"); |
| 395 | } |
| 396 | |
| 397 | static bool_t process_msg2(struct site *st, struct buffer_if *msg2, |
| 398 | struct sockaddr_in *src) |
| 399 | { |
| 400 | struct msg m; |
| 401 | cstring_t err; |
| 402 | |
| 403 | if (!unpick_msg(st,LABEL_MSG2,msg2,&m)) return False; |
| 404 | if (!check_msg(st,LABEL_MSG2,&m,&err)) { |
| 405 | slog(st,LOG_SEC,"msg2: %s",err); |
| 406 | return False; |
| 407 | } |
| 408 | st->setup_session_id=m.source; |
| 409 | memcpy(st->remoteN,m.nR,NONCELEN); |
| 410 | return True; |
| 411 | } |
| 412 | |
| 413 | static bool_t generate_msg3(struct site *st) |
| 414 | { |
| 415 | /* Now we have our nonce and their nonce. Think of a secret key, |
| 416 | and create message number 3. */ |
| 417 | st->random->generate(st->random->st,st->dh->len,st->dhsecret); |
| 418 | return generate_msg(st,LABEL_MSG3,"site:MSG3"); |
| 419 | } |
| 420 | |
| 421 | static bool_t process_msg3(struct site *st, struct buffer_if *msg3, |
| 422 | struct sockaddr_in *src) |
| 423 | { |
| 424 | struct msg m; |
| 425 | uint8_t *hash; |
| 426 | void *hst; |
| 427 | cstring_t err; |
| 428 | |
| 429 | if (!unpick_msg(st,LABEL_MSG3,msg3,&m)) return False; |
| 430 | if (!check_msg(st,LABEL_MSG3,&m,&err)) { |
| 431 | slog(st,LOG_SEC,"msg3: %s",err); |
| 432 | return False; |
| 433 | } |
| 434 | |
| 435 | /* Check signature and store g^x mod m */ |
| 436 | hash=safe_malloc(st->hash->len, "process_msg3"); |
| 437 | hst=st->hash->init(); |
| 438 | st->hash->update(hst,m.hashstart,m.hashlen); |
| 439 | st->hash->final(hst,hash); |
| 440 | /* Terminate signature with a '0' - cheating, but should be ok */ |
| 441 | m.sig[m.siglen]=0; |
| 442 | if (!st->pubkey->check(st->pubkey->st,hash,st->hash->len,m.sig)) { |
| 443 | slog(st,LOG_SEC,"msg3 signature failed check!"); |
| 444 | free(hash); |
| 445 | return False; |
| 446 | } |
| 447 | free(hash); |
| 448 | |
| 449 | /* Terminate their DH public key with a '0' */ |
| 450 | m.pk[m.pklen]=0; |
| 451 | /* Invent our DH secret key */ |
| 452 | st->random->generate(st->random->st,st->dh->len,st->dhsecret); |
| 453 | |
| 454 | /* Generate the shared key */ |
| 455 | st->dh->makeshared(st->dh->st,st->dhsecret,st->dh->len,m.pk, |
| 456 | st->sharedsecret,st->transform->keylen); |
| 457 | |
| 458 | /* Set up the transform */ |
| 459 | st->new_transform->setkey(st->new_transform->st,st->sharedsecret, |
| 460 | st->transform->keylen); |
| 461 | |
| 462 | return True; |
| 463 | } |
| 464 | |
| 465 | static bool_t generate_msg4(struct site *st) |
| 466 | { |
| 467 | /* We have both nonces, their public key and our private key. Generate |
| 468 | our public key, sign it and send it to them. */ |
| 469 | return generate_msg(st,LABEL_MSG4,"site:MSG4"); |
| 470 | } |
| 471 | |
| 472 | static bool_t process_msg4(struct site *st, struct buffer_if *msg4, |
| 473 | struct sockaddr_in *src) |
| 474 | { |
| 475 | struct msg m; |
| 476 | uint8_t *hash; |
| 477 | void *hst; |
| 478 | cstring_t err; |
| 479 | |
| 480 | if (!unpick_msg(st,LABEL_MSG4,msg4,&m)) return False; |
| 481 | if (!check_msg(st,LABEL_MSG4,&m,&err)) { |
| 482 | slog(st,LOG_SEC,"msg4: %s",err); |
| 483 | return False; |
| 484 | } |
| 485 | |
| 486 | /* Check signature and store g^x mod m */ |
| 487 | hash=safe_malloc(st->hash->len, "process_msg4"); |
| 488 | hst=st->hash->init(); |
| 489 | st->hash->update(hst,m.hashstart,m.hashlen); |
| 490 | st->hash->final(hst,hash); |
| 491 | /* Terminate signature with a '0' - cheating, but should be ok */ |
| 492 | m.sig[m.siglen]=0; |
| 493 | if (!st->pubkey->check(st->pubkey->st,hash,st->hash->len,m.sig)) { |
| 494 | slog(st,LOG_SEC,"msg4 signature failed check!"); |
| 495 | free(hash); |
| 496 | return False; |
| 497 | } |
| 498 | free(hash); |
| 499 | |
| 500 | /* Terminate their DH public key with a '0' */ |
| 501 | m.pk[m.pklen]=0; |
| 502 | /* Generate the shared key */ |
| 503 | st->dh->makeshared(st->dh->st,st->dhsecret,st->dh->len,m.pk, |
| 504 | st->sharedsecret,st->transform->keylen); |
| 505 | /* Set up the transform */ |
| 506 | st->new_transform->setkey(st->new_transform->st,st->sharedsecret, |
| 507 | st->transform->keylen); |
| 508 | |
| 509 | return True; |
| 510 | } |
| 511 | |
| 512 | struct msg0 { |
| 513 | uint32_t dest; |
| 514 | uint32_t source; |
| 515 | uint32_t type; |
| 516 | }; |
| 517 | |
| 518 | static bool_t unpick_msg0(struct site *st, struct buffer_if *msg0, |
| 519 | struct msg0 *m) |
| 520 | { |
| 521 | CHECK_AVAIL(msg0,4); |
| 522 | m->dest=buf_unprepend_uint32(msg0); |
| 523 | CHECK_AVAIL(msg0,4); |
| 524 | m->source=buf_unprepend_uint32(msg0); |
| 525 | CHECK_AVAIL(msg0,4); |
| 526 | m->type=buf_unprepend_uint32(msg0); |
| 527 | return True; |
| 528 | /* Leaves transformed part of buffer untouched */ |
| 529 | } |
| 530 | |
| 531 | static bool_t generate_msg5(struct site *st) |
| 532 | { |
| 533 | cstring_t transform_err; |
| 534 | |
| 535 | BUF_ALLOC(&st->buffer,"site:MSG5"); |
| 536 | /* We are going to add four words to the message */ |
| 537 | buffer_init(&st->buffer,st->transform->max_start_pad+(4*4)); |
| 538 | /* Give the netlink code an opportunity to put its own stuff in the |
| 539 | message (configuration information, etc.) */ |
| 540 | st->netlink->output_config(st->netlink->st,&st->buffer); |
| 541 | buf_prepend_uint32(&st->buffer,LABEL_MSG5); |
| 542 | st->new_transform->forwards(st->new_transform->st,&st->buffer, |
| 543 | &transform_err); |
| 544 | buf_prepend_uint32(&st->buffer,LABEL_MSG5); |
| 545 | buf_prepend_uint32(&st->buffer,(uint32_t)st); |
| 546 | buf_prepend_uint32(&st->buffer,st->setup_session_id); |
| 547 | |
| 548 | st->retries=st->setup_retries; |
| 549 | return True; |
| 550 | } |
| 551 | |
| 552 | static bool_t process_msg5(struct site *st, struct buffer_if *msg5, |
| 553 | struct sockaddr_in *src) |
| 554 | { |
| 555 | struct msg0 m; |
| 556 | cstring_t transform_err; |
| 557 | |
| 558 | if (!unpick_msg0(st,msg5,&m)) return False; |
| 559 | |
| 560 | if (st->new_transform->reverse(st->new_transform->st, |
| 561 | msg5,&transform_err)) { |
| 562 | /* There's a problem */ |
| 563 | slog(st,LOG_SEC,"process_msg5: transform: %s",transform_err); |
| 564 | return False; |
| 565 | } |
| 566 | /* Buffer should now contain untransformed PING packet data */ |
| 567 | CHECK_AVAIL(msg5,4); |
| 568 | if (buf_unprepend_uint32(msg5)!=LABEL_MSG5) { |
| 569 | slog(st,LOG_SEC,"MSG5/PING packet contained wrong label"); |
| 570 | return False; |
| 571 | } |
| 572 | if (!st->netlink->check_config(st->netlink->st,msg5)) { |
| 573 | slog(st,LOG_SEC,"MSG5/PING packet contained bad netlink config"); |
| 574 | return False; |
| 575 | } |
| 576 | CHECK_EMPTY(msg5); |
| 577 | return True; |
| 578 | } |
| 579 | |
| 580 | static bool_t generate_msg6(struct site *st) |
| 581 | { |
| 582 | cstring_t transform_err; |
| 583 | |
| 584 | BUF_ALLOC(&st->buffer,"site:MSG6"); |
| 585 | /* We are going to add four words to the message */ |
| 586 | buffer_init(&st->buffer,st->transform->max_start_pad+(4*4)); |
| 587 | /* Give the netlink code an opportunity to put its own stuff in the |
| 588 | message (configuration information, etc.) */ |
| 589 | st->netlink->output_config(st->netlink->st,&st->buffer); |
| 590 | buf_prepend_uint32(&st->buffer,LABEL_MSG6); |
| 591 | st->new_transform->forwards(st->new_transform->st,&st->buffer, |
| 592 | &transform_err); |
| 593 | buf_prepend_uint32(&st->buffer,LABEL_MSG6); |
| 594 | buf_prepend_uint32(&st->buffer,(uint32_t)st); |
| 595 | buf_prepend_uint32(&st->buffer,st->setup_session_id); |
| 596 | |
| 597 | st->retries=1; /* Peer will retransmit MSG5 if this packet gets lost */ |
| 598 | return True; |
| 599 | } |
| 600 | |
| 601 | static bool_t process_msg6(struct site *st, struct buffer_if *msg6, |
| 602 | struct sockaddr_in *src) |
| 603 | { |
| 604 | struct msg0 m; |
| 605 | cstring_t transform_err; |
| 606 | |
| 607 | if (!unpick_msg0(st,msg6,&m)) return False; |
| 608 | |
| 609 | if (st->new_transform->reverse(st->new_transform->st, |
| 610 | msg6,&transform_err)) { |
| 611 | /* There's a problem */ |
| 612 | slog(st,LOG_SEC,"process_msg6: transform: %s",transform_err); |
| 613 | return False; |
| 614 | } |
| 615 | /* Buffer should now contain untransformed PING packet data */ |
| 616 | CHECK_AVAIL(msg6,4); |
| 617 | if (buf_unprepend_uint32(msg6)!=LABEL_MSG6) { |
| 618 | slog(st,LOG_SEC,"MSG6/PONG packet contained invalid data"); |
| 619 | return False; |
| 620 | } |
| 621 | if (!st->netlink->check_config(st->netlink->st,msg6)) { |
| 622 | slog(st,LOG_SEC,"MSG6/PONG packet contained bad netlink config"); |
| 623 | return False; |
| 624 | } |
| 625 | CHECK_EMPTY(msg6); |
| 626 | return True; |
| 627 | } |
| 628 | |
| 629 | static bool_t process_msg0(struct site *st, struct buffer_if *msg0, |
| 630 | struct sockaddr_in *src) |
| 631 | { |
| 632 | struct msg0 m; |
| 633 | cstring_t transform_err; |
| 634 | uint32_t type; |
| 635 | |
| 636 | if (!st->current_valid) { |
| 637 | slog(st,LOG_DROP,"incoming message but no current key -> dropping"); |
| 638 | return initiate_key_setup(st,"incoming message but no current key"); |
| 639 | } |
| 640 | |
| 641 | if (!unpick_msg0(st,msg0,&m)) return False; |
| 642 | |
| 643 | if (st->current_transform->reverse(st->current_transform->st, |
| 644 | msg0,&transform_err)) { |
| 645 | /* There's a problem */ |
| 646 | slog(st,LOG_SEC,"transform: %s",transform_err); |
| 647 | return initiate_key_setup(st,"incoming message would not decrypt"); |
| 648 | } |
| 649 | CHECK_AVAIL(msg0,4); |
| 650 | type=buf_unprepend_uint32(msg0); |
| 651 | switch(type) { |
| 652 | case LABEL_MSG7: |
| 653 | /* We must forget about the current session. */ |
| 654 | delete_key(st,"request from peer",LOG_SEC); |
| 655 | return True; |
| 656 | break; |
| 657 | case LABEL_MSG9: |
| 658 | /* Deliver to netlink layer */ |
| 659 | st->netlink->deliver(st->netlink->st,msg0); |
| 660 | return True; |
| 661 | break; |
| 662 | default: |
| 663 | slog(st,LOG_SEC,"incoming encrypted message of type %08x " |
| 664 | "(unknown)",type); |
| 665 | break; |
| 666 | } |
| 667 | return False; |
| 668 | } |
| 669 | |
| 670 | static void dump_packet(struct site *st, struct buffer_if *buf, |
| 671 | struct sockaddr_in *addr, bool_t incoming) |
| 672 | { |
| 673 | uint32_t dest=ntohl(*(uint32_t *)buf->start); |
| 674 | uint32_t source=ntohl(*(uint32_t *)(buf->start+4)); |
| 675 | uint32_t msgtype=ntohl(*(uint32_t *)(buf->start+8)); |
| 676 | |
| 677 | if (st->log_events & LOG_DUMP) |
| 678 | slilog(st->log,M_DEBUG,"%s: %s: %08x<-%08x: %08x:", |
| 679 | st->tunname,incoming?"incoming":"outgoing", |
| 680 | dest,source,msgtype); |
| 681 | } |
| 682 | |
| 683 | static uint32_t site_status(void *st) |
| 684 | { |
| 685 | return 0; |
| 686 | } |
| 687 | |
| 688 | static bool_t send_msg(struct site *st) |
| 689 | { |
| 690 | if (st->retries>0) { |
| 691 | dump_packet(st,&st->buffer,&st->setup_peer,False); |
| 692 | st->comm->sendmsg(st->comm->st,&st->buffer,&st->setup_peer); |
| 693 | st->timeout=st->now+st->setup_timeout; |
| 694 | st->retries--; |
| 695 | return True; |
| 696 | } else { |
| 697 | slog(st,LOG_SETUP_TIMEOUT,"timed out sending key setup packet " |
| 698 | "(in state %s)",state_name(st->state)); |
| 699 | enter_state_wait(st); |
| 700 | return False; |
| 701 | } |
| 702 | } |
| 703 | |
| 704 | static void site_resolve_callback(void *sst, struct in_addr *address) |
| 705 | { |
| 706 | struct site *st=sst; |
| 707 | |
| 708 | if (st->state!=SITE_RESOLVE) { |
| 709 | slog(st,LOG_UNEXPECTED,"site_resolve_callback called unexpectedly"); |
| 710 | return; |
| 711 | } |
| 712 | if (address) { |
| 713 | memset(&st->setup_peer,0,sizeof(st->setup_peer)); |
| 714 | st->setup_peer.sin_family=AF_INET; |
| 715 | st->setup_peer.sin_port=htons(st->remoteport); |
| 716 | st->setup_peer.sin_addr=*address; |
| 717 | enter_new_state(st,SITE_SENTMSG1); |
| 718 | } else { |
| 719 | /* Resolution failed */ |
| 720 | slog(st,LOG_ERROR,"resolution of %s failed",st->address); |
| 721 | enter_state_run(st); |
| 722 | } |
| 723 | } |
| 724 | |
| 725 | static bool_t initiate_key_setup(struct site *st, cstring_t reason) |
| 726 | { |
| 727 | if (st->state!=SITE_RUN) return False; |
| 728 | slog(st,LOG_SETUP_INIT,"initiating key exchange (%s)",reason); |
| 729 | if (st->address) { |
| 730 | slog(st,LOG_SETUP_INIT,"resolving peer address"); |
| 731 | return enter_state_resolve(st); |
| 732 | } else if (st->peer_valid) { |
| 733 | slog(st,LOG_SETUP_INIT,"using old peer address"); |
| 734 | st->setup_peer=st->peer; |
| 735 | return enter_new_state(st,SITE_SENTMSG1); |
| 736 | } |
| 737 | slog(st,LOG_SETUP_INIT,"key exchange failed: no address for peer"); |
| 738 | return False; |
| 739 | } |
| 740 | |
| 741 | static void activate_new_key(struct site *st) |
| 742 | { |
| 743 | struct transform_inst_if *t; |
| 744 | |
| 745 | /* We have two transform instances, which we swap between active |
| 746 | and setup */ |
| 747 | t=st->current_transform; |
| 748 | st->current_transform=st->new_transform; |
| 749 | st->new_transform=t; |
| 750 | |
| 751 | t->delkey(t->st); |
| 752 | st->timeout=0; |
| 753 | st->current_valid=True; |
| 754 | st->current_key_timeout=st->now+st->key_lifetime; |
| 755 | st->renegotiate_key_time=st->now+st->key_renegotiate_time; |
| 756 | st->peer=st->setup_peer; |
| 757 | st->peer_valid=True; |
| 758 | st->remote_session_id=st->setup_session_id; |
| 759 | |
| 760 | slog(st,LOG_ACTIVATE_KEY,"new key activated"); |
| 761 | enter_state_run(st); |
| 762 | } |
| 763 | |
| 764 | static void delete_key(struct site *st, cstring_t reason, uint32_t loglevel) |
| 765 | { |
| 766 | if (st->current_valid) { |
| 767 | slog(st,loglevel,"session closed (%s)",reason); |
| 768 | |
| 769 | st->current_valid=False; |
| 770 | st->current_transform->delkey(st->current_transform->st); |
| 771 | st->current_key_timeout=0; |
| 772 | set_link_quality(st); |
| 773 | } |
| 774 | } |
| 775 | |
| 776 | static void state_assert(struct site *st, bool_t ok) |
| 777 | { |
| 778 | if (!ok) fatal("site:state_assert"); |
| 779 | } |
| 780 | |
| 781 | static void enter_state_stop(struct site *st) |
| 782 | { |
| 783 | st->state=SITE_STOP; |
| 784 | st->timeout=0; |
| 785 | delete_key(st,"entering state STOP",LOG_TIMEOUT_KEY); |
| 786 | st->new_transform->delkey(st->new_transform->st); |
| 787 | } |
| 788 | |
| 789 | static void set_link_quality(struct site *st) |
| 790 | { |
| 791 | uint32_t quality; |
| 792 | if (st->current_valid) |
| 793 | quality=LINK_QUALITY_UP; |
| 794 | else if (st->state==SITE_WAIT || st->state==SITE_STOP) |
| 795 | quality=LINK_QUALITY_DOWN; |
| 796 | else if (st->address) |
| 797 | quality=LINK_QUALITY_DOWN_CURRENT_ADDRESS; |
| 798 | else if (st->peer_valid) |
| 799 | quality=LINK_QUALITY_DOWN_STALE_ADDRESS; |
| 800 | else |
| 801 | quality=LINK_QUALITY_DOWN; |
| 802 | |
| 803 | st->netlink->set_quality(st->netlink->st,quality); |
| 804 | } |
| 805 | |
| 806 | static void enter_state_run(struct site *st) |
| 807 | { |
| 808 | slog(st,LOG_STATE,"entering state RUN"); |
| 809 | st->state=SITE_RUN; |
| 810 | st->timeout=0; |
| 811 | |
| 812 | st->setup_session_id=0; |
| 813 | memset(&st->setup_peer,0,sizeof(st->setup_peer)); |
| 814 | memset(st->localN,0,NONCELEN); |
| 815 | memset(st->remoteN,0,NONCELEN); |
| 816 | st->new_transform->delkey(st->new_transform->st); |
| 817 | memset(st->dhsecret,0,st->dh->len); |
| 818 | memset(st->sharedsecret,0,st->transform->keylen); |
| 819 | set_link_quality(st); |
| 820 | } |
| 821 | |
| 822 | static bool_t enter_state_resolve(struct site *st) |
| 823 | { |
| 824 | state_assert(st,st->state==SITE_RUN); |
| 825 | slog(st,LOG_STATE,"entering state RESOLVE"); |
| 826 | st->state=SITE_RESOLVE; |
| 827 | st->resolver->request(st->resolver->st,st->address, |
| 828 | site_resolve_callback,st); |
| 829 | return True; |
| 830 | } |
| 831 | |
| 832 | static bool_t enter_new_state(struct site *st, uint32_t next) |
| 833 | { |
| 834 | bool_t (*gen)(struct site *st); |
| 835 | int r; |
| 836 | |
| 837 | slog(st,LOG_STATE,"entering state %s",state_name(next)); |
| 838 | switch(next) { |
| 839 | case SITE_SENTMSG1: |
| 840 | state_assert(st,st->state==SITE_RUN || st->state==SITE_RESOLVE); |
| 841 | gen=generate_msg1; |
| 842 | break; |
| 843 | case SITE_SENTMSG2: |
| 844 | state_assert(st,st->state==SITE_RUN || st->state==SITE_RESOLVE || |
| 845 | st->state==SITE_SENTMSG1 || st->state==SITE_WAIT); |
| 846 | gen=generate_msg2; |
| 847 | break; |
| 848 | case SITE_SENTMSG3: |
| 849 | state_assert(st,st->state==SITE_SENTMSG1); |
| 850 | BUF_FREE(&st->buffer); |
| 851 | gen=generate_msg3; |
| 852 | break; |
| 853 | case SITE_SENTMSG4: |
| 854 | state_assert(st,st->state==SITE_SENTMSG2); |
| 855 | BUF_FREE(&st->buffer); |
| 856 | gen=generate_msg4; |
| 857 | break; |
| 858 | case SITE_SENTMSG5: |
| 859 | state_assert(st,st->state==SITE_SENTMSG3); |
| 860 | BUF_FREE(&st->buffer); |
| 861 | gen=generate_msg5; |
| 862 | break; |
| 863 | case SITE_RUN: |
| 864 | state_assert(st,st->state==SITE_SENTMSG4); |
| 865 | BUF_FREE(&st->buffer); |
| 866 | gen=generate_msg6; |
| 867 | break; |
| 868 | default: |
| 869 | gen=NULL; |
| 870 | fatal("enter_new_state(%s): invalid new state",state_name(next)); |
| 871 | break; |
| 872 | } |
| 873 | |
| 874 | if (hacky_par_start_failnow()) return False; |
| 875 | |
| 876 | r= gen(st) && send_msg(st); |
| 877 | |
| 878 | hacky_par_end(&r, |
| 879 | st->setup_retries, st->setup_timeout, |
| 880 | send_msg, st); |
| 881 | |
| 882 | if (r) { |
| 883 | st->state=next; |
| 884 | if (next==SITE_RUN) { |
| 885 | BUF_FREE(&st->buffer); /* Never reused */ |
| 886 | st->timeout=0; /* Never retransmit */ |
| 887 | activate_new_key(st); |
| 888 | } |
| 889 | return True; |
| 890 | } |
| 891 | slog(st,LOG_ERROR,"error entering state %s",state_name(next)); |
| 892 | st->buffer.free=False; /* Unconditionally use the buffer; it may be |
| 893 | in either state, and enter_state_wait() will |
| 894 | do a BUF_FREE() */ |
| 895 | enter_state_wait(st); |
| 896 | return False; |
| 897 | } |
| 898 | |
| 899 | /* msg7 tells our peer that we're about to forget our key */ |
| 900 | static bool_t send_msg7(struct site *st, cstring_t reason) |
| 901 | { |
| 902 | cstring_t transform_err; |
| 903 | |
| 904 | if (st->current_valid && st->peer_valid && st->buffer.free) { |
| 905 | BUF_ALLOC(&st->buffer,"site:MSG7"); |
| 906 | buffer_init(&st->buffer,st->transform->max_start_pad+(4*3)); |
| 907 | buf_append_uint32(&st->buffer,LABEL_MSG7); |
| 908 | buf_append_string(&st->buffer,reason); |
| 909 | st->current_transform->forwards(st->current_transform->st, |
| 910 | &st->buffer, &transform_err); |
| 911 | buf_prepend_uint32(&st->buffer,LABEL_MSG0); |
| 912 | buf_prepend_uint32(&st->buffer,(uint32_t)st); |
| 913 | buf_prepend_uint32(&st->buffer,st->remote_session_id); |
| 914 | st->comm->sendmsg(st->comm->st,&st->buffer,&st->peer); |
| 915 | BUF_FREE(&st->buffer); |
| 916 | return True; |
| 917 | } |
| 918 | return False; |
| 919 | } |
| 920 | |
| 921 | /* We go into this state if our peer becomes uncommunicative. Similar to |
| 922 | the "stop" state, we forget all session keys for a while, before |
| 923 | re-entering the "run" state. */ |
| 924 | static void enter_state_wait(struct site *st) |
| 925 | { |
| 926 | slog(st,LOG_STATE,"entering state WAIT"); |
| 927 | st->timeout=st->now+st->wait_timeout; |
| 928 | st->state=SITE_WAIT; |
| 929 | st->peer_valid=False; |
| 930 | set_link_quality(st); |
| 931 | BUF_FREE(&st->buffer); /* will have had an outgoing packet in it */ |
| 932 | /* XXX Erase keys etc. */ |
| 933 | } |
| 934 | |
| 935 | static inline void site_settimeout(uint64_t timeout, int *timeout_io) |
| 936 | { |
| 937 | if (timeout) { |
| 938 | int64_t offset=timeout-*now; |
| 939 | if (offset<0) offset=0; |
| 940 | if (offset>INT_MAX) offset=INT_MAX; |
| 941 | if (*timeout_io<0 || offset<*timeout_io) |
| 942 | *timeout_io=offset; |
| 943 | } |
| 944 | } |
| 945 | |
| 946 | static int site_beforepoll(void *sst, struct pollfd *fds, int *nfds_io, |
| 947 | int *timeout_io) |
| 948 | { |
| 949 | struct site *st=sst; |
| 950 | |
| 951 | *nfds_io=0; /* We don't use any file descriptors */ |
| 952 | st->now=*now; |
| 953 | |
| 954 | /* Work out when our next timeout is. The earlier of 'timeout' or |
| 955 | 'current_key_timeout'. A stored value of '0' indicates no timeout |
| 956 | active. */ |
| 957 | site_settimeout(st->timeout, timeout_io); |
| 958 | site_settimeout(st->current_key_timeout, timeout_io); |
| 959 | |
| 960 | return 0; /* success */ |
| 961 | } |
| 962 | |
| 963 | /* NB site_afterpoll will be called before site_beforepoll is ever called */ |
| 964 | static void site_afterpoll(void *sst, struct pollfd *fds, int nfds) |
| 965 | { |
| 966 | struct site *st=sst; |
| 967 | |
| 968 | st->now=*now; |
| 969 | if (st->timeout && *now>st->timeout) { |
| 970 | st->timeout=0; |
| 971 | if (st->state>=SITE_SENTMSG1 && st->state<=SITE_SENTMSG5) { |
| 972 | if (!hacky_par_start_failnow()) |
| 973 | send_msg(st); |
| 974 | } else if (st->state==SITE_WAIT) { |
| 975 | enter_state_run(st); |
| 976 | } else { |
| 977 | slog(st,LOG_ERROR,"site_afterpoll: unexpected timeout, state=%d", |
| 978 | st->state); |
| 979 | } |
| 980 | } |
| 981 | if (st->current_key_timeout && *now>st->current_key_timeout) { |
| 982 | delete_key(st,"maximum key life exceeded",LOG_TIMEOUT_KEY); |
| 983 | } |
| 984 | } |
| 985 | |
| 986 | /* This function is called by the netlink device to deliver packets |
| 987 | intended for the remote network. The packet is in "raw" wire |
| 988 | format, but is guaranteed to be word-aligned. */ |
| 989 | static void site_outgoing(void *sst, struct buffer_if *buf) |
| 990 | { |
| 991 | struct site *st=sst; |
| 992 | cstring_t transform_err; |
| 993 | |
| 994 | if (st->state==SITE_STOP) { |
| 995 | BUF_FREE(buf); |
| 996 | return; |
| 997 | } |
| 998 | |
| 999 | /* In all other states we consider delivering the packet if we have |
| 1000 | a valid key and a valid address to send it to. */ |
| 1001 | if (st->current_valid && st->peer_valid) { |
| 1002 | /* Transform it and send it */ |
| 1003 | if (buf->size>0) { |
| 1004 | buf_prepend_uint32(buf,LABEL_MSG9); |
| 1005 | st->current_transform->forwards(st->current_transform->st, |
| 1006 | buf, &transform_err); |
| 1007 | buf_prepend_uint32(buf,LABEL_MSG0); |
| 1008 | buf_prepend_uint32(buf,(uint32_t)st); |
| 1009 | buf_prepend_uint32(buf,st->remote_session_id); |
| 1010 | st->comm->sendmsg(st->comm->st,buf,&st->peer); |
| 1011 | } |
| 1012 | BUF_FREE(buf); |
| 1013 | /* See whether we should start negotiating a new key */ |
| 1014 | if (st->now > st->renegotiate_key_time) |
| 1015 | initiate_key_setup(st,"outgoing packet in renegotiation window"); |
| 1016 | return; |
| 1017 | } |
| 1018 | |
| 1019 | slog(st,LOG_DROP,"discarding outgoing packet of size %d",buf->size); |
| 1020 | BUF_FREE(buf); |
| 1021 | initiate_key_setup(st,"outgoing packet"); |
| 1022 | } |
| 1023 | |
| 1024 | /* This function is called by the communication device to deliver |
| 1025 | packets from our peers. */ |
| 1026 | static bool_t site_incoming(void *sst, struct buffer_if *buf, |
| 1027 | struct sockaddr_in *source) |
| 1028 | { |
| 1029 | struct site *st=sst; |
| 1030 | uint32_t dest=ntohl(*(uint32_t *)buf->start); |
| 1031 | |
| 1032 | if (dest==0) { |
| 1033 | /* It could be for any site - it should have LABEL_MSG1 and |
| 1034 | might have our name and our peer's name in it */ |
| 1035 | if (buf->size<(st->setupsiglen+8+NONCELEN)) return False; |
| 1036 | if (memcmp(buf->start+8,st->setupsig,st->setupsiglen)==0) { |
| 1037 | /* It's addressed to us. Decide what to do about it. */ |
| 1038 | dump_packet(st,buf,source,True); |
| 1039 | if (st->state==SITE_RUN || st->state==SITE_RESOLVE || |
| 1040 | st->state==SITE_WAIT) { |
| 1041 | /* We should definitely process it */ |
| 1042 | if (process_msg1(st,buf,source)) { |
| 1043 | slog(st,LOG_SETUP_INIT,"key setup initiated by peer"); |
| 1044 | enter_new_state(st,SITE_SENTMSG2); |
| 1045 | } else { |
| 1046 | slog(st,LOG_ERROR,"failed to process incoming msg1"); |
| 1047 | } |
| 1048 | BUF_FREE(buf); |
| 1049 | return True; |
| 1050 | } else if (st->state==SITE_SENTMSG1) { |
| 1051 | /* We've just sent a message 1! They may have crossed on |
| 1052 | the wire. If we have priority then we ignore the |
| 1053 | incoming one, otherwise we process it as usual. */ |
| 1054 | if (st->setup_priority) { |
| 1055 | BUF_FREE(buf); |
| 1056 | slog(st,LOG_DUMP,"crossed msg1s; we are higher " |
| 1057 | "priority => ignore incoming msg1"); |
| 1058 | return True; |
| 1059 | } else { |
| 1060 | slog(st,LOG_DUMP,"crossed msg1s; we are lower " |
| 1061 | "priority => use incoming msg1"); |
| 1062 | if (process_msg1(st,buf,source)) { |
| 1063 | BUF_FREE(&st->buffer); /* Free our old message 1 */ |
| 1064 | enter_new_state(st,SITE_SENTMSG2); |
| 1065 | } else { |
| 1066 | slog(st,LOG_ERROR,"failed to process an incoming " |
| 1067 | "crossed msg1 (we have low priority)"); |
| 1068 | } |
| 1069 | BUF_FREE(buf); |
| 1070 | return True; |
| 1071 | } |
| 1072 | } |
| 1073 | /* The message 1 was received at an unexpected stage of the |
| 1074 | key setup. XXX POLICY - what do we do? */ |
| 1075 | slog(st,LOG_UNEXPECTED,"unexpected incoming message 1"); |
| 1076 | BUF_FREE(buf); |
| 1077 | return True; |
| 1078 | } |
| 1079 | return False; /* Not for us. */ |
| 1080 | } |
| 1081 | if (dest==(uint32_t)st) { |
| 1082 | /* Explicitly addressed to us */ |
| 1083 | uint32_t msgtype=ntohl(get_uint32(buf->start+8)); |
| 1084 | if (msgtype!=LABEL_MSG0) dump_packet(st,buf,source,True); |
| 1085 | switch (msgtype) { |
| 1086 | case 0: /* NAK */ |
| 1087 | /* If the source is our current peer then initiate a key setup, |
| 1088 | because our peer's forgotten the key */ |
| 1089 | if (get_uint32(buf->start+4)==st->remote_session_id) { |
| 1090 | initiate_key_setup(st,"received a NAK"); |
| 1091 | } else { |
| 1092 | slog(st,LOG_SEC,"bad incoming NAK"); |
| 1093 | } |
| 1094 | break; |
| 1095 | case LABEL_MSG0: |
| 1096 | process_msg0(st,buf,source); |
| 1097 | break; |
| 1098 | case LABEL_MSG1: |
| 1099 | /* Setup packet: should not have been explicitly addressed |
| 1100 | to us */ |
| 1101 | slog(st,LOG_SEC,"incoming explicitly addressed msg1"); |
| 1102 | break; |
| 1103 | case LABEL_MSG2: |
| 1104 | /* Setup packet: expected only in state SENTMSG1 */ |
| 1105 | if (st->state!=SITE_SENTMSG1) { |
| 1106 | slog(st,LOG_UNEXPECTED,"unexpected MSG2"); |
| 1107 | } else if (process_msg2(st,buf,source)) |
| 1108 | enter_new_state(st,SITE_SENTMSG3); |
| 1109 | else { |
| 1110 | slog(st,LOG_SEC,"invalid MSG2"); |
| 1111 | } |
| 1112 | break; |
| 1113 | case LABEL_MSG3: |
| 1114 | /* Setup packet: expected only in state SENTMSG2 */ |
| 1115 | if (st->state!=SITE_SENTMSG2) { |
| 1116 | slog(st,LOG_UNEXPECTED,"unexpected MSG3"); |
| 1117 | } else if (process_msg3(st,buf,source)) |
| 1118 | enter_new_state(st,SITE_SENTMSG4); |
| 1119 | else { |
| 1120 | slog(st,LOG_SEC,"invalid MSG3"); |
| 1121 | } |
| 1122 | break; |
| 1123 | case LABEL_MSG4: |
| 1124 | /* Setup packet: expected only in state SENTMSG3 */ |
| 1125 | if (st->state!=SITE_SENTMSG3) { |
| 1126 | slog(st,LOG_UNEXPECTED,"unexpected MSG4"); |
| 1127 | } else if (process_msg4(st,buf,source)) |
| 1128 | enter_new_state(st,SITE_SENTMSG5); |
| 1129 | else { |
| 1130 | slog(st,LOG_SEC,"invalid MSG4"); |
| 1131 | } |
| 1132 | break; |
| 1133 | case LABEL_MSG5: |
| 1134 | /* Setup packet: expected only in state SENTMSG4 */ |
| 1135 | /* (may turn up in state RUN if our return MSG6 was lost |
| 1136 | and the new key has already been activated. In that |
| 1137 | case we should treat it as an ordinary PING packet. We |
| 1138 | can't pass it to process_msg5() because the |
| 1139 | new_transform will now be unkeyed. XXX) */ |
| 1140 | if (st->state!=SITE_SENTMSG4) { |
| 1141 | slog(st,LOG_UNEXPECTED,"unexpected MSG5"); |
| 1142 | } else if (process_msg5(st,buf,source)) { |
| 1143 | enter_new_state(st,SITE_RUN); |
| 1144 | } else { |
| 1145 | slog(st,LOG_SEC,"invalid MSG5"); |
| 1146 | } |
| 1147 | break; |
| 1148 | case LABEL_MSG6: |
| 1149 | /* Setup packet: expected only in state SENTMSG5 */ |
| 1150 | if (st->state!=SITE_SENTMSG5) { |
| 1151 | slog(st,LOG_UNEXPECTED,"unexpected MSG6"); |
| 1152 | } else if (process_msg6(st,buf,source)) { |
| 1153 | BUF_FREE(&st->buffer); /* Free message 5 */ |
| 1154 | activate_new_key(st); |
| 1155 | } else { |
| 1156 | slog(st,LOG_SEC,"invalid MSG6"); |
| 1157 | } |
| 1158 | break; |
| 1159 | default: |
| 1160 | slog(st,LOG_SEC,"received message of unknown type 0x%08x", |
| 1161 | msgtype); |
| 1162 | break; |
| 1163 | } |
| 1164 | BUF_FREE(buf); |
| 1165 | return True; |
| 1166 | } |
| 1167 | |
| 1168 | return False; |
| 1169 | } |
| 1170 | |
| 1171 | static void site_control(void *vst, bool_t run) |
| 1172 | { |
| 1173 | struct site *st=vst; |
| 1174 | if (run) enter_state_run(st); |
| 1175 | else enter_state_stop(st); |
| 1176 | } |
| 1177 | |
| 1178 | static void site_phase_hook(void *sst, uint32_t newphase) |
| 1179 | { |
| 1180 | struct site *st=sst; |
| 1181 | |
| 1182 | /* The program is shutting down; tell our peer */ |
| 1183 | send_msg7(st,"shutting down"); |
| 1184 | } |
| 1185 | |
| 1186 | static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, |
| 1187 | list_t *args) |
| 1188 | { |
| 1189 | struct site *st; |
| 1190 | item_t *item; |
| 1191 | dict_t *dict; |
| 1192 | |
| 1193 | st=safe_malloc(sizeof(*st),"site_apply"); |
| 1194 | |
| 1195 | st->cl.description="site"; |
| 1196 | st->cl.type=CL_SITE; |
| 1197 | st->cl.apply=NULL; |
| 1198 | st->cl.interface=&st->ops; |
| 1199 | st->ops.st=st; |
| 1200 | st->ops.control=site_control; |
| 1201 | st->ops.status=site_status; |
| 1202 | |
| 1203 | /* First parameter must be a dict */ |
| 1204 | item=list_elem(args,0); |
| 1205 | if (!item || item->type!=t_dict) |
| 1206 | cfgfatal(loc,"site","parameter must be a dictionary\n"); |
| 1207 | |
| 1208 | dict=item->data.dict; |
| 1209 | st->localname=dict_read_string(dict, "local-name", True, "site", loc); |
| 1210 | st->remotename=dict_read_string(dict, "name", True, "site", loc); |
| 1211 | /* Sanity check (which also allows the 'sites' file to include |
| 1212 | site() closures for all sites including our own): refuse to |
| 1213 | talk to ourselves */ |
| 1214 | if (strcmp(st->localname,st->remotename)==0) { |
| 1215 | Message(M_DEBUG,"site %s: local-name==name -> ignoring this site\n", |
| 1216 | st->localname); |
| 1217 | free(st); |
| 1218 | return NULL; |
| 1219 | } |
| 1220 | st->netlink=find_cl_if(dict,"link",CL_NETLINK,True,"site",loc); |
| 1221 | st->comm=find_cl_if(dict,"comm",CL_COMM,True,"site",loc); |
| 1222 | st->resolver=find_cl_if(dict,"resolver",CL_RESOLVER,True,"site",loc); |
| 1223 | st->log=find_cl_if(dict,"log",CL_LOG,True,"site",loc); |
| 1224 | st->random=find_cl_if(dict,"random",CL_RANDOMSRC,True,"site",loc); |
| 1225 | |
| 1226 | st->privkey=find_cl_if(dict,"local-key",CL_RSAPRIVKEY,True,"site",loc); |
| 1227 | st->address=dict_read_string(dict, "address", False, "site", loc); |
| 1228 | if (st->address) |
| 1229 | st->remoteport=dict_read_number(dict,"port",True,"site",loc,0); |
| 1230 | else st->remoteport=0; |
| 1231 | st->pubkey=find_cl_if(dict,"key",CL_RSAPUBKEY,True,"site",loc); |
| 1232 | |
| 1233 | st->transform= |
| 1234 | find_cl_if(dict,"transform",CL_TRANSFORM,True,"site",loc); |
| 1235 | |
| 1236 | st->dh=find_cl_if(dict,"dh",CL_DH,True,"site",loc); |
| 1237 | st->hash=find_cl_if(dict,"hash",CL_HASH,True,"site",loc); |
| 1238 | |
| 1239 | st->key_lifetime=dict_read_number( |
| 1240 | dict,"key-lifetime",False,"site",loc,DEFAULT_KEY_LIFETIME); |
| 1241 | st->setup_retries=dict_read_number( |
| 1242 | dict,"setup-retries",False,"site",loc,DEFAULT_SETUP_RETRIES); |
| 1243 | st->setup_timeout=dict_read_number( |
| 1244 | dict,"setup-timeout",False,"site",loc,DEFAULT_SETUP_TIMEOUT); |
| 1245 | st->wait_timeout=dict_read_number( |
| 1246 | dict,"wait-time",False,"site",loc,DEFAULT_WAIT_TIME); |
| 1247 | |
| 1248 | if (st->key_lifetime < DEFAULT_KEY_RENEGOTIATE_GAP*2) |
| 1249 | st->key_renegotiate_time=st->key_lifetime/2; |
| 1250 | else |
| 1251 | st->key_renegotiate_time=st->key_lifetime-DEFAULT_KEY_RENEGOTIATE_GAP; |
| 1252 | st->key_renegotiate_time=dict_read_number( |
| 1253 | dict,"renegotiate-time",False,"site",loc,st->key_renegotiate_time); |
| 1254 | if (st->key_renegotiate_time > st->key_lifetime) { |
| 1255 | cfgfatal(loc,"site", |
| 1256 | "renegotiate-time must be less than key-lifetime\n"); |
| 1257 | } |
| 1258 | st->keepalive=dict_read_bool(dict,"keepalive",False,"site",loc,False); |
| 1259 | |
| 1260 | st->log_events=string_list_to_word(dict_lookup(dict,"log-events"), |
| 1261 | log_event_table,"site"); |
| 1262 | |
| 1263 | st->tunname=safe_malloc(strlen(st->localname)+strlen(st->remotename)+5, |
| 1264 | "site_apply"); |
| 1265 | sprintf(st->tunname,"%s<->%s",st->localname,st->remotename); |
| 1266 | |
| 1267 | /* The information we expect to see in incoming messages of type 1 */ |
| 1268 | /* fixme: lots of unchecked overflows here, but the results are only |
| 1269 | corrupted packets rather than undefined behaviour */ |
| 1270 | st->setupsiglen=strlen(st->remotename)+strlen(st->localname)+8; |
| 1271 | st->setupsig=safe_malloc(st->setupsiglen,"site_apply"); |
| 1272 | put_uint32(st->setupsig+0,LABEL_MSG1); |
| 1273 | put_uint16(st->setupsig+4,strlen(st->remotename)); |
| 1274 | memcpy(&st->setupsig[6],st->remotename,strlen(st->remotename)); |
| 1275 | put_uint16(st->setupsig+(6+strlen(st->remotename)),strlen(st->localname)); |
| 1276 | memcpy(&st->setupsig[8+strlen(st->remotename)],st->localname, |
| 1277 | strlen(st->localname)); |
| 1278 | st->setup_priority=(strcmp(st->localname,st->remotename)>0); |
| 1279 | |
| 1280 | buffer_new(&st->buffer,SETUP_BUFFER_LEN); |
| 1281 | |
| 1282 | /* We are interested in poll(), but only for timeouts. We don't have |
| 1283 | any fds of our own. */ |
| 1284 | register_for_poll(st, site_beforepoll, site_afterpoll, 0, "site"); |
| 1285 | st->timeout=0; |
| 1286 | |
| 1287 | st->current_valid=False; |
| 1288 | st->current_key_timeout=0; |
| 1289 | st->peer_valid=False; |
| 1290 | /* XXX mlock these */ |
| 1291 | st->dhsecret=safe_malloc(st->dh->len,"site:dhsecret"); |
| 1292 | st->sharedsecret=safe_malloc(st->transform->keylen,"site:sharedsecret"); |
| 1293 | |
| 1294 | /* We need to register the remote networks with the netlink device */ |
| 1295 | st->netlink->reg(st->netlink->st, site_outgoing, st, |
| 1296 | st->transform->max_start_pad+(4*4)+ |
| 1297 | st->comm->min_start_pad, |
| 1298 | st->transform->max_end_pad+st->comm->min_end_pad); |
| 1299 | |
| 1300 | st->comm->request_notify(st->comm->st, st, site_incoming); |
| 1301 | |
| 1302 | st->current_transform=st->transform->create(st->transform->st); |
| 1303 | st->new_transform=st->transform->create(st->transform->st); |
| 1304 | |
| 1305 | enter_state_stop(st); |
| 1306 | |
| 1307 | add_hook(PHASE_SHUTDOWN,site_phase_hook,st); |
| 1308 | |
| 1309 | return new_closure(&st->cl); |
| 1310 | } |
| 1311 | |
| 1312 | void site_module(dict_t *dict) |
| 1313 | { |
| 1314 | add_closure(dict,"site",site_apply); |
| 1315 | } |