Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame^] | 1 | /*** WARNING - THIS HAS NEVER BEEN FINISHED ***/ |
| 2 | /***************************************************************************** |
| 3 | * chap.c - Network Challenge Handshake Authentication Protocol program file. |
| 4 | * |
| 5 | * Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc. |
| 6 | * portions Copyright (c) 1997 by Global Election Systems Inc. |
| 7 | * |
| 8 | * The authors hereby grant permission to use, copy, modify, distribute, |
| 9 | * and license this software and its documentation for any purpose, provided |
| 10 | * that existing copyright notices are retained in all copies and that this |
| 11 | * notice and the following disclaimer are included verbatim in any |
| 12 | * distributions. No written agreement, license, or royalty fee is required |
| 13 | * for any of the authorized uses. |
| 14 | * |
| 15 | * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR |
| 16 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 17 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 18 | * IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 19 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 20 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 21 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 22 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 23 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 24 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 25 | * |
| 26 | ****************************************************************************** |
| 27 | * REVISION HISTORY |
| 28 | * |
| 29 | * 03-01-01 Marc Boucher <marc@mbsi.ca> |
| 30 | * Ported to lwIP. |
| 31 | * 97-12-04 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc. |
| 32 | * Original based on BSD chap.c. |
| 33 | *****************************************************************************/ |
| 34 | /* |
| 35 | * chap.c - Challenge Handshake Authentication Protocol. |
| 36 | * |
| 37 | * Copyright (c) 1993 The Australian National University. |
| 38 | * All rights reserved. |
| 39 | * |
| 40 | * Redistribution and use in source and binary forms are permitted |
| 41 | * provided that the above copyright notice and this paragraph are |
| 42 | * duplicated in all such forms and that any documentation, |
| 43 | * advertising materials, and other materials related to such |
| 44 | * distribution and use acknowledge that the software was developed |
| 45 | * by the Australian National University. The name of the University |
| 46 | * may not be used to endorse or promote products derived from this |
| 47 | * software without specific prior written permission. |
| 48 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
| 49 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
| 50 | * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
| 51 | * |
| 52 | * Copyright (c) 1991 Gregory M. Christy. |
| 53 | * All rights reserved. |
| 54 | * |
| 55 | * Redistribution and use in source and binary forms are permitted |
| 56 | * provided that the above copyright notice and this paragraph are |
| 57 | * duplicated in all such forms and that any documentation, |
| 58 | * advertising materials, and other materials related to such |
| 59 | * distribution and use acknowledge that the software was developed |
| 60 | * by Gregory M. Christy. The name of the author may not be used to |
| 61 | * endorse or promote products derived from this software without |
| 62 | * specific prior written permission. |
| 63 | * |
| 64 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
| 65 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
| 66 | * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
| 67 | */ |
| 68 | |
| 69 | #include "ppp.h" |
| 70 | #if PPP_SUPPORT > 0 |
| 71 | #include "magic.h" |
| 72 | |
| 73 | #if CHAP_SUPPORT > 0 |
| 74 | |
| 75 | #include "randm.h" |
| 76 | #include "auth.h" |
| 77 | #include "md5.h" |
| 78 | #include "chap.h" |
| 79 | #include "chpms.h" |
| 80 | #include "pppdebug.h" |
| 81 | |
| 82 | |
| 83 | /*************************/ |
| 84 | /*** LOCAL DEFINITIONS ***/ |
| 85 | /*************************/ |
| 86 | |
| 87 | |
| 88 | /************************/ |
| 89 | /*** LOCAL DATA TYPES ***/ |
| 90 | /************************/ |
| 91 | |
| 92 | |
| 93 | /***********************************/ |
| 94 | /*** LOCAL FUNCTION DECLARATIONS ***/ |
| 95 | /***********************************/ |
| 96 | /* |
| 97 | * Protocol entry points. |
| 98 | */ |
| 99 | static void ChapInit (int); |
| 100 | static void ChapLowerUp (int); |
| 101 | static void ChapLowerDown (int); |
| 102 | static void ChapInput (int, u_char *, int); |
| 103 | static void ChapProtocolReject (int); |
| 104 | static int ChapPrintPkt (u_char *, int, |
| 105 | void (*) (void *, char *, ...), void *); |
| 106 | |
| 107 | static void ChapChallengeTimeout (void *); |
| 108 | static void ChapResponseTimeout (void *); |
| 109 | static void ChapReceiveChallenge (chap_state *, u_char *, int, int); |
| 110 | static void ChapRechallenge (void *); |
| 111 | static void ChapReceiveResponse (chap_state *, u_char *, int, int); |
| 112 | static void ChapReceiveSuccess(chap_state *cstate, u_char *inp, u_char id, int len); |
| 113 | static void ChapReceiveFailure(chap_state *cstate, u_char *inp, u_char id, int len); |
| 114 | static void ChapSendStatus (chap_state *, int); |
| 115 | static void ChapSendChallenge (chap_state *); |
| 116 | static void ChapSendResponse (chap_state *); |
| 117 | static void ChapGenChallenge (chap_state *); |
| 118 | |
| 119 | |
| 120 | /******************************/ |
| 121 | /*** PUBLIC DATA STRUCTURES ***/ |
| 122 | /******************************/ |
| 123 | chap_state chap[NUM_PPP]; /* CHAP state; one for each unit */ |
| 124 | |
| 125 | struct protent chap_protent = { |
| 126 | PPP_CHAP, |
| 127 | ChapInit, |
| 128 | ChapInput, |
| 129 | ChapProtocolReject, |
| 130 | ChapLowerUp, |
| 131 | ChapLowerDown, |
| 132 | NULL, |
| 133 | NULL, |
| 134 | #if 0 |
| 135 | ChapPrintPkt, |
| 136 | NULL, |
| 137 | #endif |
| 138 | 1, |
| 139 | "CHAP", |
| 140 | #if 0 |
| 141 | NULL, |
| 142 | NULL, |
| 143 | NULL |
| 144 | #endif |
| 145 | }; |
| 146 | |
| 147 | |
| 148 | |
| 149 | /*****************************/ |
| 150 | /*** LOCAL DATA STRUCTURES ***/ |
| 151 | /*****************************/ |
| 152 | static char *ChapCodenames[] = { |
| 153 | "Challenge", "Response", "Success", "Failure" |
| 154 | }; |
| 155 | |
| 156 | |
| 157 | |
| 158 | /***********************************/ |
| 159 | /*** PUBLIC FUNCTION DEFINITIONS ***/ |
| 160 | /***********************************/ |
| 161 | /* |
| 162 | * ChapAuthWithPeer - Authenticate us with our peer (start client). |
| 163 | * |
| 164 | */ |
| 165 | void ChapAuthWithPeer(int unit, char *our_name, int digest) |
| 166 | { |
| 167 | chap_state *cstate = &chap[unit]; |
| 168 | |
| 169 | cstate->resp_name = our_name; |
| 170 | cstate->resp_type = digest; |
| 171 | |
| 172 | if (cstate->clientstate == CHAPCS_INITIAL || |
| 173 | cstate->clientstate == CHAPCS_PENDING) { |
| 174 | /* lower layer isn't up - wait until later */ |
| 175 | cstate->clientstate = CHAPCS_PENDING; |
| 176 | return; |
| 177 | } |
| 178 | |
| 179 | /* |
| 180 | * We get here as a result of LCP coming up. |
| 181 | * So even if CHAP was open before, we will |
| 182 | * have to re-authenticate ourselves. |
| 183 | */ |
| 184 | cstate->clientstate = CHAPCS_LISTEN; |
| 185 | } |
| 186 | |
| 187 | |
| 188 | /* |
| 189 | * ChapAuthPeer - Authenticate our peer (start server). |
| 190 | */ |
| 191 | void ChapAuthPeer(int unit, char *our_name, int digest) |
| 192 | { |
| 193 | chap_state *cstate = &chap[unit]; |
| 194 | |
| 195 | cstate->chal_name = our_name; |
| 196 | cstate->chal_type = digest; |
| 197 | |
| 198 | if (cstate->serverstate == CHAPSS_INITIAL || |
| 199 | cstate->serverstate == CHAPSS_PENDING) { |
| 200 | /* lower layer isn't up - wait until later */ |
| 201 | cstate->serverstate = CHAPSS_PENDING; |
| 202 | return; |
| 203 | } |
| 204 | |
| 205 | ChapGenChallenge(cstate); |
| 206 | ChapSendChallenge(cstate); /* crank it up dude! */ |
| 207 | cstate->serverstate = CHAPSS_INITIAL_CHAL; |
| 208 | } |
| 209 | |
| 210 | |
| 211 | |
| 212 | |
| 213 | /**********************************/ |
| 214 | /*** LOCAL FUNCTION DEFINITIONS ***/ |
| 215 | /**********************************/ |
| 216 | /* |
| 217 | * ChapInit - Initialize a CHAP unit. |
| 218 | */ |
| 219 | static void ChapInit(int unit) |
| 220 | { |
| 221 | chap_state *cstate = &chap[unit]; |
| 222 | |
| 223 | BZERO(cstate, sizeof(*cstate)); |
| 224 | cstate->unit = unit; |
| 225 | cstate->clientstate = CHAPCS_INITIAL; |
| 226 | cstate->serverstate = CHAPSS_INITIAL; |
| 227 | cstate->timeouttime = CHAP_DEFTIMEOUT; |
| 228 | cstate->max_transmits = CHAP_DEFTRANSMITS; |
| 229 | /* random number generator is initialized in magic_init */ |
| 230 | } |
| 231 | |
| 232 | |
| 233 | /* |
| 234 | * ChapChallengeTimeout - Timeout expired on sending challenge. |
| 235 | */ |
| 236 | static void ChapChallengeTimeout(void *arg) |
| 237 | { |
| 238 | chap_state *cstate = (chap_state *) arg; |
| 239 | |
| 240 | /* if we aren't sending challenges, don't worry. then again we */ |
| 241 | /* probably shouldn't be here either */ |
| 242 | if (cstate->serverstate != CHAPSS_INITIAL_CHAL && |
| 243 | cstate->serverstate != CHAPSS_RECHALLENGE) |
| 244 | return; |
| 245 | |
| 246 | if (cstate->chal_transmits >= cstate->max_transmits) { |
| 247 | /* give up on peer */ |
| 248 | CHAPDEBUG((LOG_ERR, "Peer failed to respond to CHAP challenge\n")); |
| 249 | cstate->serverstate = CHAPSS_BADAUTH; |
| 250 | auth_peer_fail(cstate->unit, PPP_CHAP); |
| 251 | return; |
| 252 | } |
| 253 | |
| 254 | ChapSendChallenge(cstate); /* Re-send challenge */ |
| 255 | } |
| 256 | |
| 257 | |
| 258 | /* |
| 259 | * ChapResponseTimeout - Timeout expired on sending response. |
| 260 | */ |
| 261 | static void ChapResponseTimeout(void *arg) |
| 262 | { |
| 263 | chap_state *cstate = (chap_state *) arg; |
| 264 | |
| 265 | /* if we aren't sending a response, don't worry. */ |
| 266 | if (cstate->clientstate != CHAPCS_RESPONSE) |
| 267 | return; |
| 268 | |
| 269 | ChapSendResponse(cstate); /* re-send response */ |
| 270 | } |
| 271 | |
| 272 | |
| 273 | /* |
| 274 | * ChapRechallenge - Time to challenge the peer again. |
| 275 | */ |
| 276 | static void ChapRechallenge(void *arg) |
| 277 | { |
| 278 | chap_state *cstate = (chap_state *) arg; |
| 279 | |
| 280 | /* if we aren't sending a response, don't worry. */ |
| 281 | if (cstate->serverstate != CHAPSS_OPEN) |
| 282 | return; |
| 283 | |
| 284 | ChapGenChallenge(cstate); |
| 285 | ChapSendChallenge(cstate); |
| 286 | cstate->serverstate = CHAPSS_RECHALLENGE; |
| 287 | } |
| 288 | |
| 289 | |
| 290 | /* |
| 291 | * ChapLowerUp - The lower layer is up. |
| 292 | * |
| 293 | * Start up if we have pending requests. |
| 294 | */ |
| 295 | static void ChapLowerUp(int unit) |
| 296 | { |
| 297 | chap_state *cstate = &chap[unit]; |
| 298 | |
| 299 | if (cstate->clientstate == CHAPCS_INITIAL) |
| 300 | cstate->clientstate = CHAPCS_CLOSED; |
| 301 | else if (cstate->clientstate == CHAPCS_PENDING) |
| 302 | cstate->clientstate = CHAPCS_LISTEN; |
| 303 | |
| 304 | if (cstate->serverstate == CHAPSS_INITIAL) |
| 305 | cstate->serverstate = CHAPSS_CLOSED; |
| 306 | else if (cstate->serverstate == CHAPSS_PENDING) { |
| 307 | ChapGenChallenge(cstate); |
| 308 | ChapSendChallenge(cstate); |
| 309 | cstate->serverstate = CHAPSS_INITIAL_CHAL; |
| 310 | } |
| 311 | } |
| 312 | |
| 313 | |
| 314 | /* |
| 315 | * ChapLowerDown - The lower layer is down. |
| 316 | * |
| 317 | * Cancel all timeouts. |
| 318 | */ |
| 319 | static void ChapLowerDown(int unit) |
| 320 | { |
| 321 | chap_state *cstate = &chap[unit]; |
| 322 | |
| 323 | /* Timeout(s) pending? Cancel if so. */ |
| 324 | if (cstate->serverstate == CHAPSS_INITIAL_CHAL || |
| 325 | cstate->serverstate == CHAPSS_RECHALLENGE) |
| 326 | UNTIMEOUT(ChapChallengeTimeout, cstate); |
| 327 | else if (cstate->serverstate == CHAPSS_OPEN |
| 328 | && cstate->chal_interval != 0) |
| 329 | UNTIMEOUT(ChapRechallenge, cstate); |
| 330 | if (cstate->clientstate == CHAPCS_RESPONSE) |
| 331 | UNTIMEOUT(ChapResponseTimeout, cstate); |
| 332 | |
| 333 | cstate->clientstate = CHAPCS_INITIAL; |
| 334 | cstate->serverstate = CHAPSS_INITIAL; |
| 335 | } |
| 336 | |
| 337 | |
| 338 | /* |
| 339 | * ChapProtocolReject - Peer doesn't grok CHAP. |
| 340 | */ |
| 341 | static void ChapProtocolReject(int unit) |
| 342 | { |
| 343 | chap_state *cstate = &chap[unit]; |
| 344 | |
| 345 | if (cstate->serverstate != CHAPSS_INITIAL && |
| 346 | cstate->serverstate != CHAPSS_CLOSED) |
| 347 | auth_peer_fail(unit, PPP_CHAP); |
| 348 | if (cstate->clientstate != CHAPCS_INITIAL && |
| 349 | cstate->clientstate != CHAPCS_CLOSED) |
| 350 | auth_withpeer_fail(unit, PPP_CHAP); |
| 351 | ChapLowerDown(unit); /* shutdown chap */ |
| 352 | } |
| 353 | |
| 354 | |
| 355 | /* |
| 356 | * ChapInput - Input CHAP packet. |
| 357 | */ |
| 358 | static void ChapInput(int unit, u_char *inpacket, int packet_len) |
| 359 | { |
| 360 | chap_state *cstate = &chap[unit]; |
| 361 | u_char *inp; |
| 362 | u_char code, id; |
| 363 | int len; |
| 364 | |
| 365 | /* |
| 366 | * Parse header (code, id and length). |
| 367 | * If packet too short, drop it. |
| 368 | */ |
| 369 | inp = inpacket; |
| 370 | if (packet_len < CHAP_HEADERLEN) { |
| 371 | CHAPDEBUG((LOG_INFO, "ChapInput: rcvd short header.\n")); |
| 372 | return; |
| 373 | } |
| 374 | GETCHAR(code, inp); |
| 375 | GETCHAR(id, inp); |
| 376 | GETSHORT(len, inp); |
| 377 | if (len < CHAP_HEADERLEN) { |
| 378 | CHAPDEBUG((LOG_INFO, "ChapInput: rcvd illegal length.\n")); |
| 379 | return; |
| 380 | } |
| 381 | if (len > packet_len) { |
| 382 | CHAPDEBUG((LOG_INFO, "ChapInput: rcvd short packet.\n")); |
| 383 | return; |
| 384 | } |
| 385 | len -= CHAP_HEADERLEN; |
| 386 | |
| 387 | /* |
| 388 | * Action depends on code (as in fact it usually does :-). |
| 389 | */ |
| 390 | switch (code) { |
| 391 | case CHAP_CHALLENGE: |
| 392 | ChapReceiveChallenge(cstate, inp, id, len); |
| 393 | break; |
| 394 | |
| 395 | case CHAP_RESPONSE: |
| 396 | ChapReceiveResponse(cstate, inp, id, len); |
| 397 | break; |
| 398 | |
| 399 | case CHAP_FAILURE: |
| 400 | ChapReceiveFailure(cstate, inp, id, len); |
| 401 | break; |
| 402 | |
| 403 | case CHAP_SUCCESS: |
| 404 | ChapReceiveSuccess(cstate, inp, id, len); |
| 405 | break; |
| 406 | |
| 407 | default: /* Need code reject? */ |
| 408 | CHAPDEBUG((LOG_WARNING, "Unknown CHAP code (%d) received.\n", code)); |
| 409 | break; |
| 410 | } |
| 411 | } |
| 412 | |
| 413 | |
| 414 | /* |
| 415 | * ChapReceiveChallenge - Receive Challenge and send Response. |
| 416 | */ |
| 417 | static void ChapReceiveChallenge(chap_state *cstate, u_char *inp, int id, int len) |
| 418 | { |
| 419 | int rchallenge_len; |
| 420 | u_char *rchallenge; |
| 421 | int secret_len; |
| 422 | char secret[MAXSECRETLEN]; |
| 423 | char rhostname[256]; |
| 424 | MD5_CTX mdContext; |
| 425 | u_char hash[MD5_SIGNATURE_SIZE]; |
| 426 | |
| 427 | CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: Rcvd id %d.\n", id)); |
| 428 | if (cstate->clientstate == CHAPCS_CLOSED || |
| 429 | cstate->clientstate == CHAPCS_PENDING) { |
| 430 | CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: in state %d\n", |
| 431 | cstate->clientstate)); |
| 432 | return; |
| 433 | } |
| 434 | |
| 435 | if (len < 2) { |
| 436 | CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: rcvd short packet.\n")); |
| 437 | return; |
| 438 | } |
| 439 | |
| 440 | GETCHAR(rchallenge_len, inp); |
| 441 | len -= sizeof (u_char) + rchallenge_len; /* now name field length */ |
| 442 | if (len < 0) { |
| 443 | CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: rcvd short packet.\n")); |
| 444 | return; |
| 445 | } |
| 446 | rchallenge = inp; |
| 447 | INCPTR(rchallenge_len, inp); |
| 448 | |
| 449 | if (len >= sizeof(rhostname)) |
| 450 | len = sizeof(rhostname) - 1; |
| 451 | BCOPY(inp, rhostname, len); |
| 452 | rhostname[len] = '\000'; |
| 453 | |
| 454 | CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: received name field '%s'\n", |
| 455 | rhostname)); |
| 456 | |
| 457 | /* Microsoft doesn't send their name back in the PPP packet */ |
| 458 | if (ppp_settings.remote_name[0] != 0 && (ppp_settings.explicit_remote || rhostname[0] == 0)) { |
| 459 | strncpy(rhostname, ppp_settings.remote_name, sizeof(rhostname)); |
| 460 | rhostname[sizeof(rhostname) - 1] = 0; |
| 461 | CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: using '%s' as remote name\n", |
| 462 | rhostname)); |
| 463 | } |
| 464 | |
| 465 | /* get secret for authenticating ourselves with the specified host */ |
| 466 | if (!get_secret(cstate->unit, cstate->resp_name, rhostname, |
| 467 | secret, &secret_len, 0)) { |
| 468 | secret_len = 0; /* assume null secret if can't find one */ |
| 469 | CHAPDEBUG((LOG_WARNING, "No CHAP secret found for authenticating us to %s\n", rhostname)); |
| 470 | } |
| 471 | |
| 472 | /* cancel response send timeout if necessary */ |
| 473 | if (cstate->clientstate == CHAPCS_RESPONSE) |
| 474 | UNTIMEOUT(ChapResponseTimeout, cstate); |
| 475 | |
| 476 | cstate->resp_id = id; |
| 477 | cstate->resp_transmits = 0; |
| 478 | |
| 479 | /* generate MD based on negotiated type */ |
| 480 | switch (cstate->resp_type) { |
| 481 | |
| 482 | case CHAP_DIGEST_MD5: |
| 483 | MD5Init(&mdContext); |
| 484 | MD5Update(&mdContext, &cstate->resp_id, 1); |
| 485 | MD5Update(&mdContext, (u_char*)secret, secret_len); |
| 486 | MD5Update(&mdContext, rchallenge, rchallenge_len); |
| 487 | MD5Final(hash, &mdContext); |
| 488 | BCOPY(hash, cstate->response, MD5_SIGNATURE_SIZE); |
| 489 | cstate->resp_length = MD5_SIGNATURE_SIZE; |
| 490 | break; |
| 491 | |
| 492 | #ifdef CHAPMS |
| 493 | case CHAP_MICROSOFT: |
| 494 | ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len); |
| 495 | break; |
| 496 | #endif |
| 497 | |
| 498 | default: |
| 499 | CHAPDEBUG((LOG_INFO, "unknown digest type %d\n", cstate->resp_type)); |
| 500 | return; |
| 501 | } |
| 502 | |
| 503 | BZERO(secret, sizeof(secret)); |
| 504 | ChapSendResponse(cstate); |
| 505 | } |
| 506 | |
| 507 | |
| 508 | /* |
| 509 | * ChapReceiveResponse - Receive and process response. |
| 510 | */ |
| 511 | static void ChapReceiveResponse(chap_state *cstate, u_char *inp, int id, int len) |
| 512 | { |
| 513 | u_char *remmd, remmd_len; |
| 514 | int secret_len, old_state; |
| 515 | int code; |
| 516 | char rhostname[256]; |
| 517 | MD5_CTX mdContext; |
| 518 | char secret[MAXSECRETLEN]; |
| 519 | u_char hash[MD5_SIGNATURE_SIZE]; |
| 520 | |
| 521 | CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: Rcvd id %d.\n", id)); |
| 522 | |
| 523 | if (cstate->serverstate == CHAPSS_CLOSED || |
| 524 | cstate->serverstate == CHAPSS_PENDING) { |
| 525 | CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: in state %d\n", |
| 526 | cstate->serverstate)); |
| 527 | return; |
| 528 | } |
| 529 | |
| 530 | if (id != cstate->chal_id) |
| 531 | return; /* doesn't match ID of last challenge */ |
| 532 | |
| 533 | /* |
| 534 | * If we have received a duplicate or bogus Response, |
| 535 | * we have to send the same answer (Success/Failure) |
| 536 | * as we did for the first Response we saw. |
| 537 | */ |
| 538 | if (cstate->serverstate == CHAPSS_OPEN) { |
| 539 | ChapSendStatus(cstate, CHAP_SUCCESS); |
| 540 | return; |
| 541 | } |
| 542 | if (cstate->serverstate == CHAPSS_BADAUTH) { |
| 543 | ChapSendStatus(cstate, CHAP_FAILURE); |
| 544 | return; |
| 545 | } |
| 546 | |
| 547 | if (len < 2) { |
| 548 | CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: rcvd short packet.\n")); |
| 549 | return; |
| 550 | } |
| 551 | GETCHAR(remmd_len, inp); /* get length of MD */ |
| 552 | remmd = inp; /* get pointer to MD */ |
| 553 | INCPTR(remmd_len, inp); |
| 554 | |
| 555 | len -= sizeof (u_char) + remmd_len; |
| 556 | if (len < 0) { |
| 557 | CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: rcvd short packet.\n")); |
| 558 | return; |
| 559 | } |
| 560 | |
| 561 | UNTIMEOUT(ChapChallengeTimeout, cstate); |
| 562 | |
| 563 | if (len >= sizeof(rhostname)) |
| 564 | len = sizeof(rhostname) - 1; |
| 565 | BCOPY(inp, rhostname, len); |
| 566 | rhostname[len] = '\000'; |
| 567 | |
| 568 | CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: received name field: %s\n", |
| 569 | rhostname)); |
| 570 | |
| 571 | /* |
| 572 | * Get secret for authenticating them with us, |
| 573 | * do the hash ourselves, and compare the result. |
| 574 | */ |
| 575 | code = CHAP_FAILURE; |
| 576 | if (!get_secret(cstate->unit, rhostname, cstate->chal_name, |
| 577 | secret, &secret_len, 1)) { |
| 578 | /* CHAPDEBUG((LOG_WARNING, TL_CHAP, "No CHAP secret found for authenticating %s\n", rhostname)); */ |
| 579 | CHAPDEBUG((LOG_WARNING, "No CHAP secret found for authenticating %s\n", |
| 580 | rhostname)); |
| 581 | } else { |
| 582 | |
| 583 | /* generate MD based on negotiated type */ |
| 584 | switch (cstate->chal_type) { |
| 585 | |
| 586 | case CHAP_DIGEST_MD5: /* only MD5 is defined for now */ |
| 587 | if (remmd_len != MD5_SIGNATURE_SIZE) |
| 588 | break; /* it's not even the right length */ |
| 589 | MD5Init(&mdContext); |
| 590 | MD5Update(&mdContext, &cstate->chal_id, 1); |
| 591 | MD5Update(&mdContext, (u_char*)secret, secret_len); |
| 592 | MD5Update(&mdContext, cstate->challenge, cstate->chal_len); |
| 593 | MD5Final(hash, &mdContext); |
| 594 | |
| 595 | /* compare local and remote MDs and send the appropriate status */ |
| 596 | if (memcmp (hash, remmd, MD5_SIGNATURE_SIZE) == 0) |
| 597 | code = CHAP_SUCCESS; /* they are the same! */ |
| 598 | break; |
| 599 | |
| 600 | default: |
| 601 | CHAPDEBUG((LOG_INFO, "unknown digest type %d\n", cstate->chal_type)); |
| 602 | } |
| 603 | } |
| 604 | |
| 605 | BZERO(secret, sizeof(secret)); |
| 606 | ChapSendStatus(cstate, code); |
| 607 | |
| 608 | if (code == CHAP_SUCCESS) { |
| 609 | old_state = cstate->serverstate; |
| 610 | cstate->serverstate = CHAPSS_OPEN; |
| 611 | if (old_state == CHAPSS_INITIAL_CHAL) { |
| 612 | auth_peer_success(cstate->unit, PPP_CHAP, rhostname, len); |
| 613 | } |
| 614 | if (cstate->chal_interval != 0) |
| 615 | TIMEOUT(ChapRechallenge, cstate, cstate->chal_interval); |
| 616 | } else { |
| 617 | CHAPDEBUG((LOG_ERR, "CHAP peer authentication failed\n")); |
| 618 | cstate->serverstate = CHAPSS_BADAUTH; |
| 619 | auth_peer_fail(cstate->unit, PPP_CHAP); |
| 620 | } |
| 621 | } |
| 622 | |
| 623 | /* |
| 624 | * ChapReceiveSuccess - Receive Success |
| 625 | */ |
| 626 | static void ChapReceiveSuccess(chap_state *cstate, u_char *inp, u_char id, int len) |
| 627 | { |
| 628 | |
| 629 | CHAPDEBUG((LOG_INFO, "ChapReceiveSuccess: Rcvd id %d.\n", id)); |
| 630 | |
| 631 | if (cstate->clientstate == CHAPCS_OPEN) |
| 632 | /* presumably an answer to a duplicate response */ |
| 633 | return; |
| 634 | |
| 635 | if (cstate->clientstate != CHAPCS_RESPONSE) { |
| 636 | /* don't know what this is */ |
| 637 | CHAPDEBUG((LOG_INFO, "ChapReceiveSuccess: in state %d\n", |
| 638 | cstate->clientstate)); |
| 639 | return; |
| 640 | } |
| 641 | |
| 642 | UNTIMEOUT(ChapResponseTimeout, cstate); |
| 643 | |
| 644 | /* |
| 645 | * Print message. |
| 646 | */ |
| 647 | if (len > 0) |
| 648 | PRINTMSG(inp, len); |
| 649 | |
| 650 | cstate->clientstate = CHAPCS_OPEN; |
| 651 | |
| 652 | auth_withpeer_success(cstate->unit, PPP_CHAP); |
| 653 | } |
| 654 | |
| 655 | |
| 656 | /* |
| 657 | * ChapReceiveFailure - Receive failure. |
| 658 | */ |
| 659 | static void ChapReceiveFailure(chap_state *cstate, u_char *inp, u_char id, int len) |
| 660 | { |
| 661 | CHAPDEBUG((LOG_INFO, "ChapReceiveFailure: Rcvd id %d.\n", id)); |
| 662 | |
| 663 | if (cstate->clientstate != CHAPCS_RESPONSE) { |
| 664 | /* don't know what this is */ |
| 665 | CHAPDEBUG((LOG_INFO, "ChapReceiveFailure: in state %d\n", |
| 666 | cstate->clientstate)); |
| 667 | return; |
| 668 | } |
| 669 | |
| 670 | UNTIMEOUT(ChapResponseTimeout, cstate); |
| 671 | |
| 672 | /* |
| 673 | * Print message. |
| 674 | */ |
| 675 | if (len > 0) |
| 676 | PRINTMSG(inp, len); |
| 677 | |
| 678 | CHAPDEBUG((LOG_ERR, "CHAP authentication failed\n")); |
| 679 | auth_withpeer_fail(cstate->unit, PPP_CHAP); |
| 680 | } |
| 681 | |
| 682 | |
| 683 | /* |
| 684 | * ChapSendChallenge - Send an Authenticate challenge. |
| 685 | */ |
| 686 | static void ChapSendChallenge(chap_state *cstate) |
| 687 | { |
| 688 | u_char *outp; |
| 689 | int chal_len, name_len; |
| 690 | int outlen; |
| 691 | |
| 692 | chal_len = cstate->chal_len; |
| 693 | name_len = strlen(cstate->chal_name); |
| 694 | outlen = CHAP_HEADERLEN + sizeof (u_char) + chal_len + name_len; |
| 695 | outp = outpacket_buf[cstate->unit]; |
| 696 | |
| 697 | MAKEHEADER(outp, PPP_CHAP); /* paste in a CHAP header */ |
| 698 | |
| 699 | PUTCHAR(CHAP_CHALLENGE, outp); |
| 700 | PUTCHAR(cstate->chal_id, outp); |
| 701 | PUTSHORT(outlen, outp); |
| 702 | |
| 703 | PUTCHAR(chal_len, outp); /* put length of challenge */ |
| 704 | BCOPY(cstate->challenge, outp, chal_len); |
| 705 | INCPTR(chal_len, outp); |
| 706 | |
| 707 | BCOPY(cstate->chal_name, outp, name_len); /* append hostname */ |
| 708 | |
| 709 | pppWrite(cstate->unit, outpacket_buf[cstate->unit], outlen + PPP_HDRLEN); |
| 710 | |
| 711 | CHAPDEBUG((LOG_INFO, "ChapSendChallenge: Sent id %d.\n", cstate->chal_id)); |
| 712 | |
| 713 | TIMEOUT(ChapChallengeTimeout, cstate, cstate->timeouttime); |
| 714 | ++cstate->chal_transmits; |
| 715 | } |
| 716 | |
| 717 | |
| 718 | /* |
| 719 | * ChapSendStatus - Send a status response (ack or nak). |
| 720 | */ |
| 721 | static void ChapSendStatus(chap_state *cstate, int code) |
| 722 | { |
| 723 | u_char *outp; |
| 724 | int outlen, msglen; |
| 725 | char msg[256]; |
| 726 | |
| 727 | if (code == CHAP_SUCCESS) |
| 728 | strcpy(msg, "Welcome!"); |
| 729 | else |
| 730 | strcpy(msg, "I don't like you. Go 'way."); |
| 731 | msglen = strlen(msg); |
| 732 | |
| 733 | outlen = CHAP_HEADERLEN + msglen; |
| 734 | outp = outpacket_buf[cstate->unit]; |
| 735 | |
| 736 | MAKEHEADER(outp, PPP_CHAP); /* paste in a header */ |
| 737 | |
| 738 | PUTCHAR(code, outp); |
| 739 | PUTCHAR(cstate->chal_id, outp); |
| 740 | PUTSHORT(outlen, outp); |
| 741 | BCOPY(msg, outp, msglen); |
| 742 | pppWrite(cstate->unit, outpacket_buf[cstate->unit], outlen + PPP_HDRLEN); |
| 743 | |
| 744 | CHAPDEBUG((LOG_INFO, "ChapSendStatus: Sent code %d, id %d.\n", code, |
| 745 | cstate->chal_id)); |
| 746 | } |
| 747 | |
| 748 | /* |
| 749 | * ChapGenChallenge is used to generate a pseudo-random challenge string of |
| 750 | * a pseudo-random length between min_len and max_len. The challenge |
| 751 | * string and its length are stored in *cstate, and various other fields of |
| 752 | * *cstate are initialized. |
| 753 | */ |
| 754 | |
| 755 | static void ChapGenChallenge(chap_state *cstate) |
| 756 | { |
| 757 | int chal_len; |
| 758 | u_char *ptr = cstate->challenge; |
| 759 | int i; |
| 760 | |
| 761 | /* pick a random challenge length between MIN_CHALLENGE_LENGTH and |
| 762 | MAX_CHALLENGE_LENGTH */ |
| 763 | chal_len = (unsigned) |
| 764 | ((((magic() >> 16) * |
| 765 | (MAX_CHALLENGE_LENGTH - MIN_CHALLENGE_LENGTH)) >> 16) |
| 766 | + MIN_CHALLENGE_LENGTH); |
| 767 | cstate->chal_len = chal_len; |
| 768 | cstate->chal_id = ++cstate->id; |
| 769 | cstate->chal_transmits = 0; |
| 770 | |
| 771 | /* generate a random string */ |
| 772 | for (i = 0; i < chal_len; i++ ) |
| 773 | *ptr++ = (char) (magic() & 0xff); |
| 774 | } |
| 775 | |
| 776 | /* |
| 777 | * ChapSendResponse - send a response packet with values as specified |
| 778 | * in *cstate. |
| 779 | */ |
| 780 | /* ARGSUSED */ |
| 781 | static void ChapSendResponse(chap_state *cstate) |
| 782 | { |
| 783 | u_char *outp; |
| 784 | int outlen, md_len, name_len; |
| 785 | |
| 786 | md_len = cstate->resp_length; |
| 787 | name_len = strlen(cstate->resp_name); |
| 788 | outlen = CHAP_HEADERLEN + sizeof (u_char) + md_len + name_len; |
| 789 | outp = outpacket_buf[cstate->unit]; |
| 790 | |
| 791 | MAKEHEADER(outp, PPP_CHAP); |
| 792 | |
| 793 | PUTCHAR(CHAP_RESPONSE, outp); /* we are a response */ |
| 794 | PUTCHAR(cstate->resp_id, outp); /* copy id from challenge packet */ |
| 795 | PUTSHORT(outlen, outp); /* packet length */ |
| 796 | |
| 797 | PUTCHAR(md_len, outp); /* length of MD */ |
| 798 | BCOPY(cstate->response, outp, md_len); /* copy MD to buffer */ |
| 799 | INCPTR(md_len, outp); |
| 800 | |
| 801 | BCOPY(cstate->resp_name, outp, name_len); /* append our name */ |
| 802 | |
| 803 | /* send the packet */ |
| 804 | pppWrite(cstate->unit, outpacket_buf[cstate->unit], outlen + PPP_HDRLEN); |
| 805 | |
| 806 | cstate->clientstate = CHAPCS_RESPONSE; |
| 807 | TIMEOUT(ChapResponseTimeout, cstate, cstate->timeouttime); |
| 808 | ++cstate->resp_transmits; |
| 809 | } |
| 810 | |
| 811 | /* |
| 812 | * ChapPrintPkt - print the contents of a CHAP packet. |
| 813 | */ |
| 814 | static int ChapPrintPkt( |
| 815 | u_char *p, |
| 816 | int plen, |
| 817 | void (*printer) (void *, char *, ...), |
| 818 | void *arg |
| 819 | ) |
| 820 | { |
| 821 | int code, id, len; |
| 822 | int clen, nlen; |
| 823 | u_char x; |
| 824 | |
| 825 | if (plen < CHAP_HEADERLEN) |
| 826 | return 0; |
| 827 | GETCHAR(code, p); |
| 828 | GETCHAR(id, p); |
| 829 | GETSHORT(len, p); |
| 830 | if (len < CHAP_HEADERLEN || len > plen) |
| 831 | return 0; |
| 832 | |
| 833 | if (code >= 1 && code <= sizeof(ChapCodenames) / sizeof(char *)) |
| 834 | printer(arg, " %s", ChapCodenames[code-1]); |
| 835 | else |
| 836 | printer(arg, " code=0x%x", code); |
| 837 | printer(arg, " id=0x%x", id); |
| 838 | len -= CHAP_HEADERLEN; |
| 839 | switch (code) { |
| 840 | case CHAP_CHALLENGE: |
| 841 | case CHAP_RESPONSE: |
| 842 | if (len < 1) |
| 843 | break; |
| 844 | clen = p[0]; |
| 845 | if (len < clen + 1) |
| 846 | break; |
| 847 | ++p; |
| 848 | nlen = len - clen - 1; |
| 849 | printer(arg, " <"); |
| 850 | for (; clen > 0; --clen) { |
| 851 | GETCHAR(x, p); |
| 852 | printer(arg, "%.2x", x); |
| 853 | } |
| 854 | printer(arg, ">, name = %.*Z", nlen, p); |
| 855 | break; |
| 856 | case CHAP_FAILURE: |
| 857 | case CHAP_SUCCESS: |
| 858 | printer(arg, " %.*Z", len, p); |
| 859 | break; |
| 860 | default: |
| 861 | for (clen = len; clen > 0; --clen) { |
| 862 | GETCHAR(x, p); |
| 863 | printer(arg, " %.2x", x); |
| 864 | } |
| 865 | } |
| 866 | |
| 867 | return len + CHAP_HEADERLEN; |
| 868 | } |
| 869 | |
| 870 | #endif |
| 871 | |
| 872 | #endif /* PPP_SUPPORT */ |