1 /* 2 * Copyright 2002 Niels Provos <provos@citi.umich.edu> 3 * Copyright 2002 Markus Friedl <markus@openbsd.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 #include "includes.h" 28 RCSID("$OpenBSD: monitor.c,v 1.29 2002/09/26 11:38:43 markus Exp $"); 29 RCSID("$FreeBSD$"); 30 31 #include <openssl/dh.h> 32 33 #ifdef SKEY 34 #ifdef OPIE 35 #include <opie.h> 36 #define skey opie 37 #define skeychallenge(k, u, c) opiechallenge((k), (u), (c)) 38 #define skey_haskey(u) opie_haskey((u)) 39 #define skey_passcheck(u, r) opie_passverify((u), (r)) 40 #else 41 #include <skey.h> 42 #endif 43 #endif 44 45 #include "ssh.h" 46 #include "auth.h" 47 #include "kex.h" 48 #include "dh.h" 49 #include "zlib.h" 50 #include "packet.h" 51 #include "auth-options.h" 52 #include "sshpty.h" 53 #include "channels.h" 54 #include "session.h" 55 #include "sshlogin.h" 56 #include "canohost.h" 57 #include "log.h" 58 #include "servconf.h" 59 #include "monitor.h" 60 #include "monitor_mm.h" 61 #include "monitor_wrap.h" 62 #include "monitor_fdpass.h" 63 #include "xmalloc.h" 64 #include "misc.h" 65 #include "buffer.h" 66 #include "bufaux.h" 67 #include "compat.h" 68 #include "ssh2.h" 69 #include "mpaux.h" 70 71 /* Imports */ 72 extern ServerOptions options; 73 extern u_int utmp_len; 74 extern Newkeys *current_keys[]; 75 extern z_stream incoming_stream; 76 extern z_stream outgoing_stream; 77 extern u_char session_id[]; 78 extern Buffer input, output; 79 extern Buffer auth_debug; 80 extern int auth_debug_init; 81 82 /* State exported from the child */ 83 84 struct { 85 z_stream incoming; 86 z_stream outgoing; 87 u_char *keyin; 88 u_int keyinlen; 89 u_char *keyout; 90 u_int keyoutlen; 91 u_char *ivin; 92 u_int ivinlen; 93 u_char *ivout; 94 u_int ivoutlen; 95 u_char *ssh1key; 96 u_int ssh1keylen; 97 int ssh1cipher; 98 int ssh1protoflags; 99 u_char *input; 100 u_int ilen; 101 u_char *output; 102 u_int olen; 103 } child_state; 104 105 /* Functions on the montior that answer unprivileged requests */ 106 107 int mm_answer_moduli(int, Buffer *); 108 int mm_answer_sign(int, Buffer *); 109 int mm_answer_pwnamallow(int, Buffer *); 110 int mm_answer_auth2_read_banner(int, Buffer *); 111 int mm_answer_authserv(int, Buffer *); 112 int mm_answer_authpassword(int, Buffer *); 113 int mm_answer_bsdauthquery(int, Buffer *); 114 int mm_answer_bsdauthrespond(int, Buffer *); 115 int mm_answer_skeyquery(int, Buffer *); 116 int mm_answer_skeyrespond(int, Buffer *); 117 int mm_answer_keyallowed(int, Buffer *); 118 int mm_answer_keyverify(int, Buffer *); 119 int mm_answer_pty(int, Buffer *); 120 int mm_answer_pty_cleanup(int, Buffer *); 121 int mm_answer_term(int, Buffer *); 122 int mm_answer_rsa_keyallowed(int, Buffer *); 123 int mm_answer_rsa_challenge(int, Buffer *); 124 int mm_answer_rsa_response(int, Buffer *); 125 int mm_answer_sesskey(int, Buffer *); 126 int mm_answer_sessid(int, Buffer *); 127 128 #ifdef USE_PAM 129 int mm_answer_pam_start(int, Buffer *); 130 int mm_answer_pam_init_ctx(int, Buffer *); 131 int mm_answer_pam_query(int, Buffer *); 132 int mm_answer_pam_respond(int, Buffer *); 133 int mm_answer_pam_free_ctx(int, Buffer *); 134 #endif 135 136 #ifdef KRB4 137 int mm_answer_krb4(int, Buffer *); 138 #endif 139 #ifdef KRB5 140 int mm_answer_krb5(int, Buffer *); 141 #endif 142 143 static Authctxt *authctxt; 144 static BIGNUM *ssh1_challenge = NULL; /* used for ssh1 rsa auth */ 145 146 /* local state for key verify */ 147 static u_char *key_blob = NULL; 148 static u_int key_bloblen = 0; 149 static int key_blobtype = MM_NOKEY; 150 static char *hostbased_cuser = NULL; 151 static char *hostbased_chost = NULL; 152 static char *auth_method = "unknown"; 153 static int session_id2_len = 0; 154 static u_char *session_id2 = NULL; 155 156 struct mon_table { 157 enum monitor_reqtype type; 158 int flags; 159 int (*f)(int, Buffer *); 160 }; 161 162 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 163 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 164 #define MON_ONCE 0x0010 /* Disable after calling */ 165 166 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 167 168 #define MON_PERMIT 0x1000 /* Request is permitted */ 169 170 struct mon_table mon_dispatch_proto20[] = { 171 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 172 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 173 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 174 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 175 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 176 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 177 #ifdef USE_PAM 178 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 179 {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx}, 180 {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query}, 181 {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond}, 182 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 183 #endif 184 #ifdef BSD_AUTH 185 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 186 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH,mm_answer_bsdauthrespond}, 187 #endif 188 #ifdef SKEY 189 {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery}, 190 {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond}, 191 #endif 192 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 193 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 194 {0, 0, NULL} 195 }; 196 197 struct mon_table mon_dispatch_postauth20[] = { 198 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 199 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 200 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 201 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 202 {MONITOR_REQ_TERM, 0, mm_answer_term}, 203 {0, 0, NULL} 204 }; 205 206 struct mon_table mon_dispatch_proto15[] = { 207 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 208 {MONITOR_REQ_SESSKEY, MON_ONCE, mm_answer_sesskey}, 209 {MONITOR_REQ_SESSID, MON_ONCE, mm_answer_sessid}, 210 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 211 {MONITOR_REQ_RSAKEYALLOWED, MON_ISAUTH, mm_answer_rsa_keyallowed}, 212 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 213 {MONITOR_REQ_RSACHALLENGE, MON_ONCE, mm_answer_rsa_challenge}, 214 {MONITOR_REQ_RSARESPONSE, MON_ONCE|MON_AUTHDECIDE, mm_answer_rsa_response}, 215 #ifdef BSD_AUTH 216 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 217 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH,mm_answer_bsdauthrespond}, 218 #endif 219 #ifdef SKEY 220 {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery}, 221 {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond}, 222 #endif 223 #ifdef USE_PAM 224 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 225 {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx}, 226 {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query}, 227 {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond}, 228 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 229 #endif 230 #ifdef KRB4 231 {MONITOR_REQ_KRB4, MON_ONCE|MON_AUTH, mm_answer_krb4}, 232 #endif 233 #ifdef KRB5 234 {MONITOR_REQ_KRB5, MON_ONCE|MON_AUTH, mm_answer_krb5}, 235 #endif 236 {0, 0, NULL} 237 }; 238 239 struct mon_table mon_dispatch_postauth15[] = { 240 {MONITOR_REQ_PTY, MON_ONCE, mm_answer_pty}, 241 {MONITOR_REQ_PTYCLEANUP, MON_ONCE, mm_answer_pty_cleanup}, 242 {MONITOR_REQ_TERM, 0, mm_answer_term}, 243 {0, 0, NULL} 244 }; 245 246 struct mon_table *mon_dispatch; 247 248 /* Specifies if a certain message is allowed at the moment */ 249 250 static void 251 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 252 { 253 while (ent->f != NULL) { 254 if (ent->type == type) { 255 ent->flags &= ~MON_PERMIT; 256 ent->flags |= permit ? MON_PERMIT : 0; 257 return; 258 } 259 ent++; 260 } 261 } 262 263 static void 264 monitor_permit_authentications(int permit) 265 { 266 struct mon_table *ent = mon_dispatch; 267 268 while (ent->f != NULL) { 269 if (ent->flags & MON_AUTH) { 270 ent->flags &= ~MON_PERMIT; 271 ent->flags |= permit ? MON_PERMIT : 0; 272 } 273 ent++; 274 } 275 } 276 277 Authctxt * 278 monitor_child_preauth(struct monitor *pmonitor) 279 { 280 struct mon_table *ent; 281 int authenticated = 0; 282 283 debug3("preauth child monitor started"); 284 285 if (compat20) { 286 mon_dispatch = mon_dispatch_proto20; 287 288 /* Permit requests for moduli and signatures */ 289 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 290 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 291 } else { 292 mon_dispatch = mon_dispatch_proto15; 293 294 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1); 295 } 296 297 authctxt = authctxt_new(); 298 299 /* The first few requests do not require asynchronous access */ 300 while (!authenticated) { 301 authenticated = monitor_read(pmonitor, mon_dispatch, &ent); 302 if (authenticated) { 303 if (!(ent->flags & MON_AUTHDECIDE)) 304 fatal("%s: unexpected authentication from %d", 305 __func__, ent->type); 306 if (authctxt->pw->pw_uid == 0 && 307 !auth_root_allowed(auth_method)) 308 authenticated = 0; 309 } 310 311 if (ent->flags & MON_AUTHDECIDE) { 312 auth_log(authctxt, authenticated, auth_method, 313 compat20 ? " ssh2" : ""); 314 if (!authenticated) 315 authctxt->failures++; 316 } 317 } 318 319 if (!authctxt->valid) 320 fatal("%s: authenticated invalid user", __func__); 321 322 debug("%s: %s has been authenticated by privileged process", 323 __func__, authctxt->user); 324 325 mm_get_keystate(pmonitor); 326 327 return (authctxt); 328 } 329 330 void 331 monitor_child_postauth(struct monitor *pmonitor) 332 { 333 if (compat20) { 334 mon_dispatch = mon_dispatch_postauth20; 335 336 /* Permit requests for moduli and signatures */ 337 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 338 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 339 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 340 341 } else { 342 mon_dispatch = mon_dispatch_postauth15; 343 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 344 } 345 if (!no_pty_flag) { 346 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 347 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 348 } 349 350 for (;;) 351 monitor_read(pmonitor, mon_dispatch, NULL); 352 } 353 354 void 355 monitor_sync(struct monitor *pmonitor) 356 { 357 if (options.compression) { 358 /* The member allocation is not visible, so sync it */ 359 mm_share_sync(&pmonitor->m_zlib, &pmonitor->m_zback); 360 } 361 } 362 363 int 364 monitor_read(struct monitor *pmonitor, struct mon_table *ent, 365 struct mon_table **pent) 366 { 367 Buffer m; 368 int ret; 369 u_char type; 370 371 buffer_init(&m); 372 373 mm_request_receive(pmonitor->m_sendfd, &m); 374 type = buffer_get_char(&m); 375 376 debug3("%s: checking request %d", __func__, type); 377 378 while (ent->f != NULL) { 379 if (ent->type == type) 380 break; 381 ent++; 382 } 383 384 if (ent->f != NULL) { 385 if (!(ent->flags & MON_PERMIT)) 386 fatal("%s: unpermitted request %d", __func__, 387 type); 388 ret = (*ent->f)(pmonitor->m_sendfd, &m); 389 buffer_free(&m); 390 391 /* The child may use this request only once, disable it */ 392 if (ent->flags & MON_ONCE) { 393 debug2("%s: %d used once, disabling now", __func__, 394 type); 395 ent->flags &= ~MON_PERMIT; 396 } 397 398 if (pent != NULL) 399 *pent = ent; 400 401 return ret; 402 } 403 404 fatal("%s: unsupported request: %d", __func__, type); 405 406 /* NOTREACHED */ 407 return (-1); 408 } 409 410 /* allowed key state */ 411 static int 412 monitor_allowed_key(u_char *blob, u_int bloblen) 413 { 414 /* make sure key is allowed */ 415 if (key_blob == NULL || key_bloblen != bloblen || 416 memcmp(key_blob, blob, key_bloblen)) 417 return (0); 418 return (1); 419 } 420 421 static void 422 monitor_reset_key_state(void) 423 { 424 /* reset state */ 425 if (key_blob != NULL) 426 xfree(key_blob); 427 if (hostbased_cuser != NULL) 428 xfree(hostbased_cuser); 429 if (hostbased_chost != NULL) 430 xfree(hostbased_chost); 431 key_blob = NULL; 432 key_bloblen = 0; 433 key_blobtype = MM_NOKEY; 434 hostbased_cuser = NULL; 435 hostbased_chost = NULL; 436 } 437 438 int 439 mm_answer_moduli(int socket, Buffer *m) 440 { 441 DH *dh; 442 int min, want, max; 443 444 min = buffer_get_int(m); 445 want = buffer_get_int(m); 446 max = buffer_get_int(m); 447 448 debug3("%s: got parameters: %d %d %d", 449 __func__, min, want, max); 450 /* We need to check here, too, in case the child got corrupted */ 451 if (max < min || want < min || max < want) 452 fatal("%s: bad parameters: %d %d %d", 453 __func__, min, want, max); 454 455 buffer_clear(m); 456 457 dh = choose_dh(min, want, max); 458 if (dh == NULL) { 459 buffer_put_char(m, 0); 460 return (0); 461 } else { 462 /* Send first bignum */ 463 buffer_put_char(m, 1); 464 buffer_put_bignum2(m, dh->p); 465 buffer_put_bignum2(m, dh->g); 466 467 DH_free(dh); 468 } 469 mm_request_send(socket, MONITOR_ANS_MODULI, m); 470 return (0); 471 } 472 473 int 474 mm_answer_sign(int socket, Buffer *m) 475 { 476 Key *key; 477 u_char *p; 478 u_char *signature; 479 u_int siglen, datlen; 480 int keyid; 481 482 debug3("%s", __func__); 483 484 keyid = buffer_get_int(m); 485 p = buffer_get_string(m, &datlen); 486 487 if (datlen != 20) 488 fatal("%s: data length incorrect: %u", __func__, datlen); 489 490 /* save session id, it will be passed on the first call */ 491 if (session_id2_len == 0) { 492 session_id2_len = datlen; 493 session_id2 = xmalloc(session_id2_len); 494 memcpy(session_id2, p, session_id2_len); 495 } 496 497 if ((key = get_hostkey_by_index(keyid)) == NULL) 498 fatal("%s: no hostkey from index %d", __func__, keyid); 499 if (key_sign(key, &signature, &siglen, p, datlen) < 0) 500 fatal("%s: key_sign failed", __func__); 501 502 debug3("%s: signature %p(%u)", __func__, signature, siglen); 503 504 buffer_clear(m); 505 buffer_put_string(m, signature, siglen); 506 507 xfree(p); 508 xfree(signature); 509 510 mm_request_send(socket, MONITOR_ANS_SIGN, m); 511 512 /* Turn on permissions for getpwnam */ 513 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 514 515 return (0); 516 } 517 518 /* Retrieves the password entry and also checks if the user is permitted */ 519 520 int 521 mm_answer_pwnamallow(int socket, Buffer *m) 522 { 523 char *login; 524 struct passwd *pwent; 525 int allowed = 0; 526 527 debug3("%s", __func__); 528 529 if (authctxt->attempt++ != 0) 530 fatal("%s: multiple attempts for getpwnam", __func__); 531 532 login = buffer_get_string(m, NULL); 533 534 pwent = getpwnamallow(login); 535 536 authctxt->user = xstrdup(login); 537 setproctitle("%s [priv]", pwent ? login : "unknown"); 538 xfree(login); 539 540 buffer_clear(m); 541 542 if (pwent == NULL) { 543 buffer_put_char(m, 0); 544 goto out; 545 } 546 547 allowed = 1; 548 authctxt->pw = pwent; 549 authctxt->valid = 1; 550 551 buffer_put_char(m, 1); 552 buffer_put_string(m, pwent, sizeof(struct passwd)); 553 buffer_put_cstring(m, pwent->pw_name); 554 buffer_put_cstring(m, "*"); 555 buffer_put_cstring(m, pwent->pw_gecos); 556 #ifdef HAVE_PW_CLASS_IN_PASSWD 557 buffer_put_cstring(m, pwent->pw_class); 558 #endif 559 buffer_put_cstring(m, pwent->pw_dir); 560 buffer_put_cstring(m, pwent->pw_shell); 561 562 out: 563 debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed); 564 mm_request_send(socket, MONITOR_ANS_PWNAM, m); 565 566 /* For SSHv1 allow authentication now */ 567 if (!compat20) 568 monitor_permit_authentications(1); 569 else { 570 /* Allow service/style information on the auth context */ 571 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 572 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 573 } 574 575 #ifdef USE_PAM 576 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); 577 #endif 578 579 return (0); 580 } 581 582 int mm_answer_auth2_read_banner(int socket, Buffer *m) 583 { 584 char *banner; 585 586 buffer_clear(m); 587 banner = auth2_read_banner(); 588 buffer_put_cstring(m, banner != NULL ? banner : ""); 589 mm_request_send(socket, MONITOR_ANS_AUTH2_READ_BANNER, m); 590 591 if (banner != NULL) 592 xfree(banner); 593 594 return (0); 595 } 596 597 int 598 mm_answer_authserv(int socket, Buffer *m) 599 { 600 monitor_permit_authentications(1); 601 602 authctxt->service = buffer_get_string(m, NULL); 603 authctxt->style = buffer_get_string(m, NULL); 604 debug3("%s: service=%s, style=%s", 605 __func__, authctxt->service, authctxt->style); 606 607 if (strlen(authctxt->style) == 0) { 608 xfree(authctxt->style); 609 authctxt->style = NULL; 610 } 611 612 return (0); 613 } 614 615 int 616 mm_answer_authpassword(int socket, Buffer *m) 617 { 618 static int call_count; 619 char *passwd; 620 int authenticated; 621 u_int plen; 622 623 passwd = buffer_get_string(m, &plen); 624 /* Only authenticate if the context is valid */ 625 authenticated = options.password_authentication && 626 authctxt->valid && auth_password(authctxt, passwd); 627 memset(passwd, 0, strlen(passwd)); 628 xfree(passwd); 629 630 buffer_clear(m); 631 buffer_put_int(m, authenticated); 632 633 debug3("%s: sending result %d", __func__, authenticated); 634 mm_request_send(socket, MONITOR_ANS_AUTHPASSWORD, m); 635 636 call_count++; 637 if (plen == 0 && call_count == 1) 638 auth_method = "none"; 639 else 640 auth_method = "password"; 641 642 /* Causes monitor loop to terminate if authenticated */ 643 return (authenticated); 644 } 645 646 #ifdef BSD_AUTH 647 int 648 mm_answer_bsdauthquery(int socket, Buffer *m) 649 { 650 char *name, *infotxt; 651 u_int numprompts; 652 u_int *echo_on; 653 char **prompts; 654 int res; 655 656 res = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 657 &prompts, &echo_on); 658 659 buffer_clear(m); 660 buffer_put_int(m, res); 661 if (res != -1) 662 buffer_put_cstring(m, prompts[0]); 663 664 debug3("%s: sending challenge res: %d", __func__, res); 665 mm_request_send(socket, MONITOR_ANS_BSDAUTHQUERY, m); 666 667 if (res != -1) { 668 xfree(name); 669 xfree(infotxt); 670 xfree(prompts); 671 xfree(echo_on); 672 } 673 674 return (0); 675 } 676 677 int 678 mm_answer_bsdauthrespond(int socket, Buffer *m) 679 { 680 char *response; 681 int authok; 682 683 if (authctxt->as == 0) 684 fatal("%s: no bsd auth session", __func__); 685 686 response = buffer_get_string(m, NULL); 687 authok = options.challenge_response_authentication && 688 auth_userresponse(authctxt->as, response, 0); 689 authctxt->as = NULL; 690 debug3("%s: <%s> = <%d>", __func__, response, authok); 691 xfree(response); 692 693 buffer_clear(m); 694 buffer_put_int(m, authok); 695 696 debug3("%s: sending authenticated: %d", __func__, authok); 697 mm_request_send(socket, MONITOR_ANS_BSDAUTHRESPOND, m); 698 699 auth_method = "bsdauth"; 700 701 return (authok != 0); 702 } 703 #endif 704 705 #ifdef SKEY 706 int 707 mm_answer_skeyquery(int socket, Buffer *m) 708 { 709 struct skey skey; 710 char challenge[1024]; 711 int res; 712 713 res = skeychallenge(&skey, authctxt->user, challenge); 714 715 buffer_clear(m); 716 buffer_put_int(m, res); 717 if (res != -1) 718 buffer_put_cstring(m, challenge); 719 720 debug3("%s: sending challenge res: %d", __func__, res); 721 mm_request_send(socket, MONITOR_ANS_SKEYQUERY, m); 722 723 return (0); 724 } 725 726 int 727 mm_answer_skeyrespond(int socket, Buffer *m) 728 { 729 char *response; 730 int authok; 731 732 response = buffer_get_string(m, NULL); 733 734 authok = (options.challenge_response_authentication && 735 authctxt->valid && 736 skey_haskey(authctxt->pw->pw_name) == 0 && 737 skey_passcheck(authctxt->pw->pw_name, response) != -1); 738 739 xfree(response); 740 741 buffer_clear(m); 742 buffer_put_int(m, authok); 743 744 debug3("%s: sending authenticated: %d", __func__, authok); 745 mm_request_send(socket, MONITOR_ANS_SKEYRESPOND, m); 746 747 auth_method = "skey"; 748 749 return (authok != 0); 750 } 751 #endif 752 753 #ifdef USE_PAM 754 int 755 mm_answer_pam_start(int socket, Buffer *m) 756 { 757 char *user; 758 759 user = buffer_get_string(m, NULL); 760 761 start_pam(user); 762 763 xfree(user); 764 765 return (0); 766 } 767 768 static void *pam_ctxt, *pam_authok; 769 extern KbdintDevice pam_device; 770 771 int 772 mm_answer_pam_init_ctx(int socket, Buffer *m) 773 { 774 775 debug3("%s", __func__); 776 authctxt->user = buffer_get_string(m, NULL); 777 pam_ctxt = (pam_device.init_ctx)(authctxt); 778 pam_authok = NULL; 779 buffer_clear(m); 780 if (pam_ctxt != NULL) { 781 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 782 buffer_put_int(m, 1); 783 } else { 784 buffer_put_int(m, 0); 785 } 786 mm_request_send(socket, MONITOR_ANS_PAM_INIT_CTX, m); 787 return (0); 788 } 789 790 int 791 mm_answer_pam_query(int socket, Buffer *m) 792 { 793 char *name, *info, **prompts; 794 u_int num, *echo_on; 795 int i, ret; 796 797 debug3("%s", __func__); 798 pam_authok = NULL; 799 ret = (pam_device.query)(pam_ctxt, &name, &info, &num, &prompts, &echo_on); 800 if (num > 1 || name == NULL || info == NULL) 801 ret = -1; 802 buffer_clear(m); 803 buffer_put_int(m, ret); 804 buffer_put_cstring(m, name); 805 xfree(name); 806 buffer_put_cstring(m, info); 807 xfree(info); 808 buffer_put_int(m, num); 809 for (i = 0; i < num; ++i) { 810 buffer_put_cstring(m, prompts[i]); 811 xfree(prompts[i]); 812 buffer_put_int(m, echo_on[i]); 813 } 814 if (prompts != NULL) 815 xfree(prompts); 816 if (echo_on != NULL) 817 xfree(echo_on); 818 mm_request_send(socket, MONITOR_ANS_PAM_QUERY, m); 819 return (0); 820 } 821 822 int 823 mm_answer_pam_respond(int socket, Buffer *m) 824 { 825 char **resp; 826 u_int num; 827 int i, ret; 828 829 debug3("%s", __func__); 830 pam_authok = NULL; 831 num = buffer_get_int(m); 832 if (num > 0) { 833 resp = xmalloc(num * sizeof(char *)); 834 for (i = 0; i < num; ++i) 835 resp[i] = buffer_get_string(m, NULL); 836 ret = (pam_device.respond)(pam_ctxt, num, resp); 837 for (i = 0; i < num; ++i) 838 xfree(resp[i]); 839 xfree(resp); 840 } else { 841 ret = (pam_device.respond)(pam_ctxt, num, NULL); 842 } 843 buffer_clear(m); 844 buffer_put_int(m, ret); 845 mm_request_send(socket, MONITOR_ANS_PAM_RESPOND, m); 846 auth_method = "keyboard-interactive/pam"; 847 if (ret == 0) 848 pam_authok = pam_ctxt; 849 return (0); 850 } 851 852 int 853 mm_answer_pam_free_ctx(int socket, Buffer *m) 854 { 855 856 debug3("%s", __func__); 857 (pam_device.free_ctx)(pam_ctxt); 858 buffer_clear(m); 859 mm_request_send(socket, MONITOR_ANS_PAM_FREE_CTX, m); 860 return (pam_authok == pam_ctxt); 861 } 862 #endif 863 864 static void 865 mm_append_debug(Buffer *m) 866 { 867 if (auth_debug_init && buffer_len(&auth_debug)) { 868 debug3("%s: Appending debug messages for child", __func__); 869 buffer_append(m, buffer_ptr(&auth_debug), 870 buffer_len(&auth_debug)); 871 buffer_clear(&auth_debug); 872 } 873 } 874 875 int 876 mm_answer_keyallowed(int socket, Buffer *m) 877 { 878 Key *key; 879 char *cuser, *chost; 880 u_char *blob; 881 u_int bloblen; 882 enum mm_keytype type = 0; 883 int allowed = 0; 884 885 debug3("%s entering", __func__); 886 887 type = buffer_get_int(m); 888 cuser = buffer_get_string(m, NULL); 889 chost = buffer_get_string(m, NULL); 890 blob = buffer_get_string(m, &bloblen); 891 892 key = key_from_blob(blob, bloblen); 893 894 if ((compat20 && type == MM_RSAHOSTKEY) || 895 (!compat20 && type != MM_RSAHOSTKEY)) 896 fatal("%s: key type and protocol mismatch", __func__); 897 898 debug3("%s: key_from_blob: %p", __func__, key); 899 900 if (key != NULL && authctxt->pw != NULL) { 901 switch(type) { 902 case MM_USERKEY: 903 allowed = options.pubkey_authentication && 904 user_key_allowed(authctxt->pw, key); 905 break; 906 case MM_HOSTKEY: 907 allowed = options.hostbased_authentication && 908 hostbased_key_allowed(authctxt->pw, 909 cuser, chost, key); 910 break; 911 case MM_RSAHOSTKEY: 912 key->type = KEY_RSA1; /* XXX */ 913 allowed = options.rhosts_rsa_authentication && 914 auth_rhosts_rsa_key_allowed(authctxt->pw, 915 cuser, chost, key); 916 break; 917 default: 918 fatal("%s: unknown key type %d", __func__, type); 919 break; 920 } 921 key_free(key); 922 } 923 924 /* clear temporarily storage (used by verify) */ 925 monitor_reset_key_state(); 926 927 if (allowed) { 928 /* Save temporarily for comparison in verify */ 929 key_blob = blob; 930 key_bloblen = bloblen; 931 key_blobtype = type; 932 hostbased_cuser = cuser; 933 hostbased_chost = chost; 934 } 935 936 debug3("%s: key %p is %s", 937 __func__, key, allowed ? "allowed" : "disallowed"); 938 939 buffer_clear(m); 940 buffer_put_int(m, allowed); 941 942 mm_append_debug(m); 943 944 mm_request_send(socket, MONITOR_ANS_KEYALLOWED, m); 945 946 if (type == MM_RSAHOSTKEY) 947 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed); 948 949 return (0); 950 } 951 952 static int 953 monitor_valid_userblob(u_char *data, u_int datalen) 954 { 955 Buffer b; 956 char *p; 957 u_int len; 958 int fail = 0; 959 960 buffer_init(&b); 961 buffer_append(&b, data, datalen); 962 963 if (datafellows & SSH_OLD_SESSIONID) { 964 p = buffer_ptr(&b); 965 len = buffer_len(&b); 966 if ((session_id2 == NULL) || 967 (len < session_id2_len) || 968 (memcmp(p, session_id2, session_id2_len) != 0)) 969 fail++; 970 buffer_consume(&b, session_id2_len); 971 } else { 972 p = buffer_get_string(&b, &len); 973 if ((session_id2 == NULL) || 974 (len != session_id2_len) || 975 (memcmp(p, session_id2, session_id2_len) != 0)) 976 fail++; 977 xfree(p); 978 } 979 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 980 fail++; 981 p = buffer_get_string(&b, NULL); 982 if (strcmp(authctxt->user, p) != 0) { 983 log("wrong user name passed to monitor: expected %s != %.100s", 984 authctxt->user, p); 985 fail++; 986 } 987 xfree(p); 988 buffer_skip_string(&b); 989 if (datafellows & SSH_BUG_PKAUTH) { 990 if (!buffer_get_char(&b)) 991 fail++; 992 } else { 993 p = buffer_get_string(&b, NULL); 994 if (strcmp("publickey", p) != 0) 995 fail++; 996 xfree(p); 997 if (!buffer_get_char(&b)) 998 fail++; 999 buffer_skip_string(&b); 1000 } 1001 buffer_skip_string(&b); 1002 if (buffer_len(&b) != 0) 1003 fail++; 1004 buffer_free(&b); 1005 return (fail == 0); 1006 } 1007 1008 static int 1009 monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser, 1010 char *chost) 1011 { 1012 Buffer b; 1013 char *p; 1014 u_int len; 1015 int fail = 0; 1016 1017 buffer_init(&b); 1018 buffer_append(&b, data, datalen); 1019 1020 p = buffer_get_string(&b, &len); 1021 if ((session_id2 == NULL) || 1022 (len != session_id2_len) || 1023 (memcmp(p, session_id2, session_id2_len) != 0)) 1024 fail++; 1025 xfree(p); 1026 1027 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 1028 fail++; 1029 p = buffer_get_string(&b, NULL); 1030 if (strcmp(authctxt->user, p) != 0) { 1031 log("wrong user name passed to monitor: expected %s != %.100s", 1032 authctxt->user, p); 1033 fail++; 1034 } 1035 xfree(p); 1036 buffer_skip_string(&b); /* service */ 1037 p = buffer_get_string(&b, NULL); 1038 if (strcmp(p, "hostbased") != 0) 1039 fail++; 1040 xfree(p); 1041 buffer_skip_string(&b); /* pkalg */ 1042 buffer_skip_string(&b); /* pkblob */ 1043 1044 /* verify client host, strip trailing dot if necessary */ 1045 p = buffer_get_string(&b, NULL); 1046 if (((len = strlen(p)) > 0) && p[len - 1] == '.') 1047 p[len - 1] = '\0'; 1048 if (strcmp(p, chost) != 0) 1049 fail++; 1050 xfree(p); 1051 1052 /* verify client user */ 1053 p = buffer_get_string(&b, NULL); 1054 if (strcmp(p, cuser) != 0) 1055 fail++; 1056 xfree(p); 1057 1058 if (buffer_len(&b) != 0) 1059 fail++; 1060 buffer_free(&b); 1061 return (fail == 0); 1062 } 1063 1064 int 1065 mm_answer_keyverify(int socket, Buffer *m) 1066 { 1067 Key *key; 1068 u_char *signature, *data, *blob; 1069 u_int signaturelen, datalen, bloblen; 1070 int verified = 0; 1071 int valid_data = 0; 1072 1073 blob = buffer_get_string(m, &bloblen); 1074 signature = buffer_get_string(m, &signaturelen); 1075 data = buffer_get_string(m, &datalen); 1076 1077 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1078 !monitor_allowed_key(blob, bloblen)) 1079 fatal("%s: bad key, not previously allowed", __func__); 1080 1081 key = key_from_blob(blob, bloblen); 1082 if (key == NULL) 1083 fatal("%s: bad public key blob", __func__); 1084 1085 switch (key_blobtype) { 1086 case MM_USERKEY: 1087 valid_data = monitor_valid_userblob(data, datalen); 1088 break; 1089 case MM_HOSTKEY: 1090 valid_data = monitor_valid_hostbasedblob(data, datalen, 1091 hostbased_cuser, hostbased_chost); 1092 break; 1093 default: 1094 valid_data = 0; 1095 break; 1096 } 1097 if (!valid_data) 1098 fatal("%s: bad signature data blob", __func__); 1099 1100 verified = key_verify(key, signature, signaturelen, data, datalen); 1101 debug3("%s: key %p signature %s", 1102 __func__, key, verified ? "verified" : "unverified"); 1103 1104 key_free(key); 1105 xfree(blob); 1106 xfree(signature); 1107 xfree(data); 1108 1109 auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased"; 1110 1111 monitor_reset_key_state(); 1112 1113 buffer_clear(m); 1114 buffer_put_int(m, verified); 1115 mm_request_send(socket, MONITOR_ANS_KEYVERIFY, m); 1116 1117 return (verified); 1118 } 1119 1120 static void 1121 mm_record_login(Session *s, struct passwd *pw) 1122 { 1123 socklen_t fromlen; 1124 struct sockaddr_storage from; 1125 1126 /* 1127 * Get IP address of client. If the connection is not a socket, let 1128 * the address be 0.0.0.0. 1129 */ 1130 memset(&from, 0, sizeof(from)); 1131 fromlen = sizeof(from); 1132 if (packet_connection_is_on_socket()) { 1133 if (getpeername(packet_get_connection_in(), 1134 (struct sockaddr *) & from, &fromlen) < 0) { 1135 debug("getpeername: %.100s", strerror(errno)); 1136 fatal_cleanup(); 1137 } 1138 } 1139 /* Record that there was a login on that tty from the remote host. */ 1140 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1141 get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping), 1142 (struct sockaddr *)&from, fromlen); 1143 } 1144 1145 static void 1146 mm_session_close(Session *s) 1147 { 1148 debug3("%s: session %d pid %d", __func__, s->self, s->pid); 1149 if (s->ttyfd != -1) { 1150 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd); 1151 fatal_remove_cleanup(session_pty_cleanup2, (void *)s); 1152 session_pty_cleanup2(s); 1153 } 1154 s->used = 0; 1155 } 1156 1157 int 1158 mm_answer_pty(int socket, Buffer *m) 1159 { 1160 extern struct monitor *pmonitor; 1161 Session *s; 1162 int res, fd0; 1163 1164 debug3("%s entering", __func__); 1165 1166 buffer_clear(m); 1167 s = session_new(); 1168 if (s == NULL) 1169 goto error; 1170 s->authctxt = authctxt; 1171 s->pw = authctxt->pw; 1172 s->pid = pmonitor->m_pid; 1173 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1174 if (res == 0) 1175 goto error; 1176 fatal_add_cleanup(session_pty_cleanup2, (void *)s); 1177 pty_setowner(authctxt->pw, s->tty); 1178 1179 buffer_put_int(m, 1); 1180 buffer_put_cstring(m, s->tty); 1181 mm_request_send(socket, MONITOR_ANS_PTY, m); 1182 1183 mm_send_fd(socket, s->ptyfd); 1184 mm_send_fd(socket, s->ttyfd); 1185 1186 /* We need to trick ttyslot */ 1187 if (dup2(s->ttyfd, 0) == -1) 1188 fatal("%s: dup2", __func__); 1189 1190 mm_record_login(s, authctxt->pw); 1191 1192 /* Now we can close the file descriptor again */ 1193 close(0); 1194 1195 /* make sure nothing uses fd 0 */ 1196 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0) 1197 fatal("%s: open(/dev/null): %s", __func__, strerror(errno)); 1198 if (fd0 != 0) 1199 error("%s: fd0 %d != 0", __func__, fd0); 1200 1201 /* slave is not needed */ 1202 close(s->ttyfd); 1203 s->ttyfd = s->ptyfd; 1204 /* no need to dup() because nobody closes ptyfd */ 1205 s->ptymaster = s->ptyfd; 1206 1207 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd); 1208 1209 return (0); 1210 1211 error: 1212 if (s != NULL) 1213 mm_session_close(s); 1214 buffer_put_int(m, 0); 1215 mm_request_send(socket, MONITOR_ANS_PTY, m); 1216 return (0); 1217 } 1218 1219 int 1220 mm_answer_pty_cleanup(int socket, Buffer *m) 1221 { 1222 Session *s; 1223 char *tty; 1224 1225 debug3("%s entering", __func__); 1226 1227 tty = buffer_get_string(m, NULL); 1228 if ((s = session_by_tty(tty)) != NULL) 1229 mm_session_close(s); 1230 buffer_clear(m); 1231 xfree(tty); 1232 return (0); 1233 } 1234 1235 int 1236 mm_answer_sesskey(int socket, Buffer *m) 1237 { 1238 BIGNUM *p; 1239 int rsafail; 1240 1241 /* Turn off permissions */ 1242 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1); 1243 1244 if ((p = BN_new()) == NULL) 1245 fatal("%s: BN_new", __func__); 1246 1247 buffer_get_bignum2(m, p); 1248 1249 rsafail = ssh1_session_key(p); 1250 1251 buffer_clear(m); 1252 buffer_put_int(m, rsafail); 1253 buffer_put_bignum2(m, p); 1254 1255 BN_clear_free(p); 1256 1257 mm_request_send(socket, MONITOR_ANS_SESSKEY, m); 1258 1259 /* Turn on permissions for sessid passing */ 1260 monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1); 1261 1262 return (0); 1263 } 1264 1265 int 1266 mm_answer_sessid(int socket, Buffer *m) 1267 { 1268 int i; 1269 1270 debug3("%s entering", __func__); 1271 1272 if (buffer_len(m) != 16) 1273 fatal("%s: bad ssh1 session id", __func__); 1274 for (i = 0; i < 16; i++) 1275 session_id[i] = buffer_get_char(m); 1276 1277 /* Turn on permissions for getpwnam */ 1278 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 1279 1280 return (0); 1281 } 1282 1283 int 1284 mm_answer_rsa_keyallowed(int socket, Buffer *m) 1285 { 1286 BIGNUM *client_n; 1287 Key *key = NULL; 1288 u_char *blob = NULL; 1289 u_int blen = 0; 1290 int allowed = 0; 1291 1292 debug3("%s entering", __func__); 1293 1294 if (options.rsa_authentication && authctxt->valid) { 1295 if ((client_n = BN_new()) == NULL) 1296 fatal("%s: BN_new", __func__); 1297 buffer_get_bignum2(m, client_n); 1298 allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key); 1299 BN_clear_free(client_n); 1300 } 1301 buffer_clear(m); 1302 buffer_put_int(m, allowed); 1303 1304 /* clear temporarily storage (used by generate challenge) */ 1305 monitor_reset_key_state(); 1306 1307 if (allowed && key != NULL) { 1308 key->type = KEY_RSA; /* cheat for key_to_blob */ 1309 if (key_to_blob(key, &blob, &blen) == 0) 1310 fatal("%s: key_to_blob failed", __func__); 1311 buffer_put_string(m, blob, blen); 1312 1313 /* Save temporarily for comparison in verify */ 1314 key_blob = blob; 1315 key_bloblen = blen; 1316 key_blobtype = MM_RSAUSERKEY; 1317 key_free(key); 1318 } 1319 1320 mm_append_debug(m); 1321 1322 mm_request_send(socket, MONITOR_ANS_RSAKEYALLOWED, m); 1323 1324 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed); 1325 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0); 1326 return (0); 1327 } 1328 1329 int 1330 mm_answer_rsa_challenge(int socket, Buffer *m) 1331 { 1332 Key *key = NULL; 1333 u_char *blob; 1334 u_int blen; 1335 1336 debug3("%s entering", __func__); 1337 1338 if (!authctxt->valid) 1339 fatal("%s: authctxt not valid", __func__); 1340 blob = buffer_get_string(m, &blen); 1341 if (!monitor_allowed_key(blob, blen)) 1342 fatal("%s: bad key, not previously allowed", __func__); 1343 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) 1344 fatal("%s: key type mismatch", __func__); 1345 if ((key = key_from_blob(blob, blen)) == NULL) 1346 fatal("%s: received bad key", __func__); 1347 1348 if (ssh1_challenge) 1349 BN_clear_free(ssh1_challenge); 1350 ssh1_challenge = auth_rsa_generate_challenge(key); 1351 1352 buffer_clear(m); 1353 buffer_put_bignum2(m, ssh1_challenge); 1354 1355 debug3("%s sending reply", __func__); 1356 mm_request_send(socket, MONITOR_ANS_RSACHALLENGE, m); 1357 1358 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1); 1359 return (0); 1360 } 1361 1362 int 1363 mm_answer_rsa_response(int socket, Buffer *m) 1364 { 1365 Key *key = NULL; 1366 u_char *blob, *response; 1367 u_int blen, len; 1368 int success; 1369 1370 debug3("%s entering", __func__); 1371 1372 if (!authctxt->valid) 1373 fatal("%s: authctxt not valid", __func__); 1374 if (ssh1_challenge == NULL) 1375 fatal("%s: no ssh1_challenge", __func__); 1376 1377 blob = buffer_get_string(m, &blen); 1378 if (!monitor_allowed_key(blob, blen)) 1379 fatal("%s: bad key, not previously allowed", __func__); 1380 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) 1381 fatal("%s: key type mismatch: %d", __func__, key_blobtype); 1382 if ((key = key_from_blob(blob, blen)) == NULL) 1383 fatal("%s: received bad key", __func__); 1384 response = buffer_get_string(m, &len); 1385 if (len != 16) 1386 fatal("%s: received bad response to challenge", __func__); 1387 success = auth_rsa_verify_response(key, ssh1_challenge, response); 1388 1389 key_free(key); 1390 xfree(response); 1391 1392 auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa"; 1393 1394 /* reset state */ 1395 BN_clear_free(ssh1_challenge); 1396 ssh1_challenge = NULL; 1397 monitor_reset_key_state(); 1398 1399 buffer_clear(m); 1400 buffer_put_int(m, success); 1401 mm_request_send(socket, MONITOR_ANS_RSARESPONSE, m); 1402 1403 return (success); 1404 } 1405 1406 #ifdef KRB4 1407 int 1408 mm_answer_krb4(int socket, Buffer *m) 1409 { 1410 KTEXT_ST auth, reply; 1411 char *client, *p; 1412 int success; 1413 u_int alen; 1414 1415 reply.length = auth.length = 0; 1416 1417 p = buffer_get_string(m, &alen); 1418 if (alen >= MAX_KTXT_LEN) 1419 fatal("%s: auth too large", __func__); 1420 memcpy(auth.dat, p, alen); 1421 auth.length = alen; 1422 memset(p, 0, alen); 1423 xfree(p); 1424 1425 success = options.kerberos_authentication && 1426 authctxt->valid && 1427 auth_krb4(authctxt, &auth, &client, &reply); 1428 1429 memset(auth.dat, 0, alen); 1430 buffer_clear(m); 1431 buffer_put_int(m, success); 1432 1433 if (success) { 1434 buffer_put_cstring(m, client); 1435 buffer_put_string(m, reply.dat, reply.length); 1436 if (client) 1437 xfree(client); 1438 if (reply.length) 1439 memset(reply.dat, 0, reply.length); 1440 } 1441 1442 debug3("%s: sending result %d", __func__, success); 1443 mm_request_send(socket, MONITOR_ANS_KRB4, m); 1444 1445 auth_method = "kerberos"; 1446 1447 /* Causes monitor loop to terminate if authenticated */ 1448 return (success); 1449 } 1450 #endif 1451 1452 #ifdef KRB5 1453 int 1454 mm_answer_krb5(int socket, Buffer *m) 1455 { 1456 krb5_data tkt, reply; 1457 char *client_user; 1458 u_int len; 1459 int success; 1460 1461 /* use temporary var to avoid size issues on 64bit arch */ 1462 tkt.data = buffer_get_string(m, &len); 1463 tkt.length = len; 1464 1465 success = options.kerberos_authentication && 1466 authctxt->valid && 1467 auth_krb5(authctxt, &tkt, &client_user, &reply); 1468 1469 if (tkt.length) 1470 xfree(tkt.data); 1471 1472 buffer_clear(m); 1473 buffer_put_int(m, success); 1474 1475 if (success) { 1476 buffer_put_cstring(m, client_user); 1477 buffer_put_string(m, reply.data, reply.length); 1478 if (client_user) 1479 xfree(client_user); 1480 if (reply.length) 1481 xfree(reply.data); 1482 } 1483 mm_request_send(socket, MONITOR_ANS_KRB5, m); 1484 1485 return success; 1486 } 1487 #endif 1488 1489 int 1490 mm_answer_term(int socket, Buffer *req) 1491 { 1492 extern struct monitor *pmonitor; 1493 int res, status; 1494 1495 debug3("%s: tearing down sessions", __func__); 1496 1497 /* The child is terminating */ 1498 session_destroy_all(&mm_session_close); 1499 1500 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1501 if (errno != EINTR) 1502 exit(1); 1503 1504 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1505 1506 /* Terminate process */ 1507 exit (res); 1508 } 1509 1510 void 1511 monitor_apply_keystate(struct monitor *pmonitor) 1512 { 1513 if (compat20) { 1514 set_newkeys(MODE_IN); 1515 set_newkeys(MODE_OUT); 1516 } else { 1517 packet_set_protocol_flags(child_state.ssh1protoflags); 1518 packet_set_encryption_key(child_state.ssh1key, 1519 child_state.ssh1keylen, child_state.ssh1cipher); 1520 xfree(child_state.ssh1key); 1521 } 1522 1523 /* for rc4 and other stateful ciphers */ 1524 packet_set_keycontext(MODE_OUT, child_state.keyout); 1525 xfree(child_state.keyout); 1526 packet_set_keycontext(MODE_IN, child_state.keyin); 1527 xfree(child_state.keyin); 1528 1529 if (!compat20) { 1530 packet_set_iv(MODE_OUT, child_state.ivout); 1531 xfree(child_state.ivout); 1532 packet_set_iv(MODE_IN, child_state.ivin); 1533 xfree(child_state.ivin); 1534 } 1535 1536 memcpy(&incoming_stream, &child_state.incoming, 1537 sizeof(incoming_stream)); 1538 memcpy(&outgoing_stream, &child_state.outgoing, 1539 sizeof(outgoing_stream)); 1540 1541 /* Update with new address */ 1542 if (options.compression) 1543 mm_init_compression(pmonitor->m_zlib); 1544 1545 /* Network I/O buffers */ 1546 /* XXX inefficient for large buffers, need: buffer_init_from_string */ 1547 buffer_clear(&input); 1548 buffer_append(&input, child_state.input, child_state.ilen); 1549 memset(child_state.input, 0, child_state.ilen); 1550 xfree(child_state.input); 1551 1552 buffer_clear(&output); 1553 buffer_append(&output, child_state.output, child_state.olen); 1554 memset(child_state.output, 0, child_state.olen); 1555 xfree(child_state.output); 1556 } 1557 1558 static Kex * 1559 mm_get_kex(Buffer *m) 1560 { 1561 Kex *kex; 1562 void *blob; 1563 u_int bloblen; 1564 1565 kex = xmalloc(sizeof(*kex)); 1566 memset(kex, 0, sizeof(*kex)); 1567 kex->session_id = buffer_get_string(m, &kex->session_id_len); 1568 if ((session_id2 == NULL) || 1569 (kex->session_id_len != session_id2_len) || 1570 (memcmp(kex->session_id, session_id2, session_id2_len) != 0)) 1571 fatal("mm_get_get: internal error: bad session id"); 1572 kex->we_need = buffer_get_int(m); 1573 kex->server = 1; 1574 kex->hostkey_type = buffer_get_int(m); 1575 kex->kex_type = buffer_get_int(m); 1576 blob = buffer_get_string(m, &bloblen); 1577 buffer_init(&kex->my); 1578 buffer_append(&kex->my, blob, bloblen); 1579 xfree(blob); 1580 blob = buffer_get_string(m, &bloblen); 1581 buffer_init(&kex->peer); 1582 buffer_append(&kex->peer, blob, bloblen); 1583 xfree(blob); 1584 kex->done = 1; 1585 kex->flags = buffer_get_int(m); 1586 kex->client_version_string = buffer_get_string(m, NULL); 1587 kex->server_version_string = buffer_get_string(m, NULL); 1588 kex->load_host_key=&get_hostkey_by_type; 1589 kex->host_key_index=&get_hostkey_index; 1590 1591 return (kex); 1592 } 1593 1594 /* This function requries careful sanity checking */ 1595 1596 void 1597 mm_get_keystate(struct monitor *pmonitor) 1598 { 1599 Buffer m; 1600 u_char *blob, *p; 1601 u_int bloblen, plen; 1602 1603 debug3("%s: Waiting for new keys", __func__); 1604 1605 buffer_init(&m); 1606 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, &m); 1607 if (!compat20) { 1608 child_state.ssh1protoflags = buffer_get_int(&m); 1609 child_state.ssh1cipher = buffer_get_int(&m); 1610 child_state.ssh1key = buffer_get_string(&m, 1611 &child_state.ssh1keylen); 1612 child_state.ivout = buffer_get_string(&m, 1613 &child_state.ivoutlen); 1614 child_state.ivin = buffer_get_string(&m, &child_state.ivinlen); 1615 goto skip; 1616 } else { 1617 /* Get the Kex for rekeying */ 1618 *pmonitor->m_pkex = mm_get_kex(&m); 1619 } 1620 1621 blob = buffer_get_string(&m, &bloblen); 1622 current_keys[MODE_OUT] = mm_newkeys_from_blob(blob, bloblen); 1623 xfree(blob); 1624 1625 debug3("%s: Waiting for second key", __func__); 1626 blob = buffer_get_string(&m, &bloblen); 1627 current_keys[MODE_IN] = mm_newkeys_from_blob(blob, bloblen); 1628 xfree(blob); 1629 1630 /* Now get sequence numbers for the packets */ 1631 packet_set_seqnr(MODE_OUT, buffer_get_int(&m)); 1632 packet_set_seqnr(MODE_IN, buffer_get_int(&m)); 1633 1634 skip: 1635 /* Get the key context */ 1636 child_state.keyout = buffer_get_string(&m, &child_state.keyoutlen); 1637 child_state.keyin = buffer_get_string(&m, &child_state.keyinlen); 1638 1639 debug3("%s: Getting compression state", __func__); 1640 /* Get compression state */ 1641 p = buffer_get_string(&m, &plen); 1642 if (plen != sizeof(child_state.outgoing)) 1643 fatal("%s: bad request size", __func__); 1644 memcpy(&child_state.outgoing, p, sizeof(child_state.outgoing)); 1645 xfree(p); 1646 1647 p = buffer_get_string(&m, &plen); 1648 if (plen != sizeof(child_state.incoming)) 1649 fatal("%s: bad request size", __func__); 1650 memcpy(&child_state.incoming, p, sizeof(child_state.incoming)); 1651 xfree(p); 1652 1653 /* Network I/O buffers */ 1654 debug3("%s: Getting Network I/O buffers", __func__); 1655 child_state.input = buffer_get_string(&m, &child_state.ilen); 1656 child_state.output = buffer_get_string(&m, &child_state.olen); 1657 1658 buffer_free(&m); 1659 } 1660 1661 1662 /* Allocation functions for zlib */ 1663 void * 1664 mm_zalloc(struct mm_master *mm, u_int ncount, u_int size) 1665 { 1666 size_t len = size * ncount; 1667 void *address; 1668 1669 if (len == 0 || ncount > SIZE_T_MAX / size) 1670 fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size); 1671 1672 address = mm_malloc(mm, len); 1673 1674 return (address); 1675 } 1676 1677 void 1678 mm_zfree(struct mm_master *mm, void *address) 1679 { 1680 mm_free(mm, address); 1681 } 1682 1683 void 1684 mm_init_compression(struct mm_master *mm) 1685 { 1686 outgoing_stream.zalloc = (alloc_func)mm_zalloc; 1687 outgoing_stream.zfree = (free_func)mm_zfree; 1688 outgoing_stream.opaque = mm; 1689 1690 incoming_stream.zalloc = (alloc_func)mm_zalloc; 1691 incoming_stream.zfree = (free_func)mm_zfree; 1692 incoming_stream.opaque = mm; 1693 } 1694 1695 /* XXX */ 1696 1697 #define FD_CLOSEONEXEC(x) do { \ 1698 if (fcntl(x, F_SETFD, 1) == -1) \ 1699 fatal("fcntl(%d, F_SETFD)", x); \ 1700 } while (0) 1701 1702 static void 1703 monitor_socketpair(int *pair) 1704 { 1705 #ifdef HAVE_SOCKETPAIR 1706 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1707 fatal("%s: socketpair", __func__); 1708 #else 1709 fatal("%s: UsePrivilegeSeparation=yes not supported", 1710 __func__); 1711 #endif 1712 FD_CLOSEONEXEC(pair[0]); 1713 FD_CLOSEONEXEC(pair[1]); 1714 } 1715 1716 #define MM_MEMSIZE 65536 1717 1718 struct monitor * 1719 monitor_init(void) 1720 { 1721 struct monitor *mon; 1722 int pair[2]; 1723 1724 mon = xmalloc(sizeof(*mon)); 1725 1726 monitor_socketpair(pair); 1727 1728 mon->m_recvfd = pair[0]; 1729 mon->m_sendfd = pair[1]; 1730 1731 /* Used to share zlib space across processes */ 1732 if (options.compression) { 1733 mon->m_zback = mm_create(NULL, MM_MEMSIZE); 1734 mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE); 1735 1736 /* Compression needs to share state across borders */ 1737 mm_init_compression(mon->m_zlib); 1738 } 1739 1740 return mon; 1741 } 1742 1743 void 1744 monitor_reinit(struct monitor *mon) 1745 { 1746 int pair[2]; 1747 1748 monitor_socketpair(pair); 1749 1750 mon->m_recvfd = pair[0]; 1751 mon->m_sendfd = pair[1]; 1752 } 1753