1 /* $OpenBSD: monitor.c,v 1.99 2008/07/10 18:08:11 markus Exp $ */ 2 /* 3 * Copyright 2002 Niels Provos <provos@citi.umich.edu> 4 * Copyright 2002 Markus Friedl <markus@openbsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include "includes.h" 29 30 #include <sys/types.h> 31 #include <sys/param.h> 32 #include <sys/socket.h> 33 #include "openbsd-compat/sys-tree.h" 34 #include <sys/wait.h> 35 36 #include <errno.h> 37 #include <fcntl.h> 38 #ifdef HAVE_PATHS_H 39 #include <paths.h> 40 #endif 41 #include <pwd.h> 42 #include <signal.h> 43 #include <stdarg.h> 44 #include <stdlib.h> 45 #include <string.h> 46 #include <unistd.h> 47 48 #ifdef SKEY 49 #include <skey.h> 50 #endif 51 52 #include <openssl/dh.h> 53 54 #include "openbsd-compat/sys-queue.h" 55 #include "xmalloc.h" 56 #include "ssh.h" 57 #include "key.h" 58 #include "buffer.h" 59 #include "hostfile.h" 60 #include "auth.h" 61 #include "cipher.h" 62 #include "kex.h" 63 #include "dh.h" 64 #ifdef TARGET_OS_MAC /* XXX Broken krb5 headers on Mac */ 65 #undef TARGET_OS_MAC 66 #include "zlib.h" 67 #define TARGET_OS_MAC 1 68 #else 69 #include "zlib.h" 70 #endif 71 #include "packet.h" 72 #include "auth-options.h" 73 #include "sshpty.h" 74 #include "channels.h" 75 #include "session.h" 76 #include "sshlogin.h" 77 #include "canohost.h" 78 #include "log.h" 79 #include "servconf.h" 80 #include "monitor.h" 81 #include "monitor_mm.h" 82 #ifdef GSSAPI 83 #include "ssh-gss.h" 84 #endif 85 #include "monitor_wrap.h" 86 #include "monitor_fdpass.h" 87 #include "misc.h" 88 #include "compat.h" 89 #include "ssh2.h" 90 91 #ifdef GSSAPI 92 static Gssctxt *gsscontext = NULL; 93 #endif 94 95 /* Imports */ 96 extern ServerOptions options; 97 extern u_int utmp_len; 98 extern Newkeys *current_keys[]; 99 extern z_stream incoming_stream; 100 extern z_stream outgoing_stream; 101 extern u_char session_id[]; 102 extern Buffer input, output; 103 extern Buffer auth_debug; 104 extern int auth_debug_init; 105 extern Buffer loginmsg; 106 107 /* State exported from the child */ 108 109 struct { 110 z_stream incoming; 111 z_stream outgoing; 112 u_char *keyin; 113 u_int keyinlen; 114 u_char *keyout; 115 u_int keyoutlen; 116 u_char *ivin; 117 u_int ivinlen; 118 u_char *ivout; 119 u_int ivoutlen; 120 u_char *ssh1key; 121 u_int ssh1keylen; 122 int ssh1cipher; 123 int ssh1protoflags; 124 u_char *input; 125 u_int ilen; 126 u_char *output; 127 u_int olen; 128 } child_state; 129 130 /* Functions on the monitor that answer unprivileged requests */ 131 132 int mm_answer_moduli(int, Buffer *); 133 int mm_answer_sign(int, Buffer *); 134 int mm_answer_pwnamallow(int, Buffer *); 135 int mm_answer_auth2_read_banner(int, Buffer *); 136 int mm_answer_authserv(int, Buffer *); 137 int mm_answer_authpassword(int, Buffer *); 138 int mm_answer_bsdauthquery(int, Buffer *); 139 int mm_answer_bsdauthrespond(int, Buffer *); 140 int mm_answer_skeyquery(int, Buffer *); 141 int mm_answer_skeyrespond(int, Buffer *); 142 int mm_answer_keyallowed(int, Buffer *); 143 int mm_answer_keyverify(int, Buffer *); 144 int mm_answer_pty(int, Buffer *); 145 int mm_answer_pty_cleanup(int, Buffer *); 146 int mm_answer_term(int, Buffer *); 147 int mm_answer_rsa_keyallowed(int, Buffer *); 148 int mm_answer_rsa_challenge(int, Buffer *); 149 int mm_answer_rsa_response(int, Buffer *); 150 int mm_answer_sesskey(int, Buffer *); 151 int mm_answer_sessid(int, Buffer *); 152 153 #ifdef USE_PAM 154 int mm_answer_pam_start(int, Buffer *); 155 int mm_answer_pam_account(int, Buffer *); 156 int mm_answer_pam_init_ctx(int, Buffer *); 157 int mm_answer_pam_query(int, Buffer *); 158 int mm_answer_pam_respond(int, Buffer *); 159 int mm_answer_pam_free_ctx(int, Buffer *); 160 #endif 161 162 #ifdef GSSAPI 163 int mm_answer_gss_setup_ctx(int, Buffer *); 164 int mm_answer_gss_accept_ctx(int, Buffer *); 165 int mm_answer_gss_userok(int, Buffer *); 166 int mm_answer_gss_checkmic(int, Buffer *); 167 #endif 168 169 #ifdef SSH_AUDIT_EVENTS 170 int mm_answer_audit_event(int, Buffer *); 171 int mm_answer_audit_command(int, Buffer *); 172 #endif 173 174 static Authctxt *authctxt; 175 static BIGNUM *ssh1_challenge = NULL; /* used for ssh1 rsa auth */ 176 177 /* local state for key verify */ 178 static u_char *key_blob = NULL; 179 static u_int key_bloblen = 0; 180 static int key_blobtype = MM_NOKEY; 181 static char *hostbased_cuser = NULL; 182 static char *hostbased_chost = NULL; 183 static char *auth_method = "unknown"; 184 static u_int session_id2_len = 0; 185 static u_char *session_id2 = NULL; 186 static pid_t monitor_child_pid; 187 188 struct mon_table { 189 enum monitor_reqtype type; 190 int flags; 191 int (*f)(int, Buffer *); 192 }; 193 194 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 195 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 196 #define MON_ONCE 0x0010 /* Disable after calling */ 197 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 198 199 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 200 201 #define MON_PERMIT 0x1000 /* Request is permitted */ 202 203 struct mon_table mon_dispatch_proto20[] = { 204 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 205 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 206 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 207 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 208 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 209 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 210 #ifdef USE_PAM 211 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 212 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 213 {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx}, 214 {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query}, 215 {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond}, 216 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 217 #endif 218 #ifdef SSH_AUDIT_EVENTS 219 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 220 #endif 221 #ifdef BSD_AUTH 222 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 223 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 224 #endif 225 #ifdef SKEY 226 {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery}, 227 {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond}, 228 #endif 229 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 230 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 231 #ifdef GSSAPI 232 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 233 {MONITOR_REQ_GSSSTEP, MON_ISAUTH, mm_answer_gss_accept_ctx}, 234 {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok}, 235 {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, mm_answer_gss_checkmic}, 236 #endif 237 {0, 0, NULL} 238 }; 239 240 struct mon_table mon_dispatch_postauth20[] = { 241 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 242 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 243 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 244 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 245 {MONITOR_REQ_TERM, 0, mm_answer_term}, 246 #ifdef SSH_AUDIT_EVENTS 247 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 248 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command}, 249 #endif 250 {0, 0, NULL} 251 }; 252 253 struct mon_table mon_dispatch_proto15[] = { 254 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 255 {MONITOR_REQ_SESSKEY, MON_ONCE, mm_answer_sesskey}, 256 {MONITOR_REQ_SESSID, MON_ONCE, mm_answer_sessid}, 257 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 258 {MONITOR_REQ_RSAKEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_rsa_keyallowed}, 259 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_keyallowed}, 260 {MONITOR_REQ_RSACHALLENGE, MON_ONCE, mm_answer_rsa_challenge}, 261 {MONITOR_REQ_RSARESPONSE, MON_ONCE|MON_AUTHDECIDE, mm_answer_rsa_response}, 262 #ifdef BSD_AUTH 263 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 264 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 265 #endif 266 #ifdef SKEY 267 {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery}, 268 {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond}, 269 #endif 270 #ifdef USE_PAM 271 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 272 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 273 {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx}, 274 {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query}, 275 {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond}, 276 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 277 #endif 278 #ifdef SSH_AUDIT_EVENTS 279 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 280 #endif 281 {0, 0, NULL} 282 }; 283 284 struct mon_table mon_dispatch_postauth15[] = { 285 {MONITOR_REQ_PTY, MON_ONCE, mm_answer_pty}, 286 {MONITOR_REQ_PTYCLEANUP, MON_ONCE, mm_answer_pty_cleanup}, 287 {MONITOR_REQ_TERM, 0, mm_answer_term}, 288 #ifdef SSH_AUDIT_EVENTS 289 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 290 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT|MON_ONCE, mm_answer_audit_command}, 291 #endif 292 {0, 0, NULL} 293 }; 294 295 struct mon_table *mon_dispatch; 296 297 /* Specifies if a certain message is allowed at the moment */ 298 299 static void 300 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 301 { 302 while (ent->f != NULL) { 303 if (ent->type == type) { 304 ent->flags &= ~MON_PERMIT; 305 ent->flags |= permit ? MON_PERMIT : 0; 306 return; 307 } 308 ent++; 309 } 310 } 311 312 static void 313 monitor_permit_authentications(int permit) 314 { 315 struct mon_table *ent = mon_dispatch; 316 317 while (ent->f != NULL) { 318 if (ent->flags & MON_AUTH) { 319 ent->flags &= ~MON_PERMIT; 320 ent->flags |= permit ? MON_PERMIT : 0; 321 } 322 ent++; 323 } 324 } 325 326 void 327 monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor) 328 { 329 struct mon_table *ent; 330 int authenticated = 0; 331 332 debug3("preauth child monitor started"); 333 334 authctxt = _authctxt; 335 memset(authctxt, 0, sizeof(*authctxt)); 336 337 authctxt->loginmsg = &loginmsg; 338 339 if (compat20) { 340 mon_dispatch = mon_dispatch_proto20; 341 342 /* Permit requests for moduli and signatures */ 343 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 344 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 345 } else { 346 mon_dispatch = mon_dispatch_proto15; 347 348 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1); 349 } 350 351 /* The first few requests do not require asynchronous access */ 352 while (!authenticated) { 353 auth_method = "unknown"; 354 authenticated = (monitor_read(pmonitor, mon_dispatch, &ent) == 1); 355 if (authenticated) { 356 if (!(ent->flags & MON_AUTHDECIDE)) 357 fatal("%s: unexpected authentication from %d", 358 __func__, ent->type); 359 if (authctxt->pw->pw_uid == 0 && 360 !auth_root_allowed(auth_method)) 361 authenticated = 0; 362 #ifdef USE_PAM 363 /* PAM needs to perform account checks after auth */ 364 if (options.use_pam && authenticated) { 365 Buffer m; 366 367 buffer_init(&m); 368 mm_request_receive_expect(pmonitor->m_sendfd, 369 MONITOR_REQ_PAM_ACCOUNT, &m); 370 authenticated = mm_answer_pam_account(pmonitor->m_sendfd, &m); 371 buffer_free(&m); 372 } 373 #endif 374 } 375 376 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 377 auth_log(authctxt, authenticated, auth_method, 378 compat20 ? " ssh2" : ""); 379 if (!authenticated) 380 authctxt->failures++; 381 } 382 } 383 384 if (!authctxt->valid) 385 fatal("%s: authenticated invalid user", __func__); 386 if (strcmp(auth_method, "unknown") == 0) 387 fatal("%s: authentication method name unknown", __func__); 388 389 debug("%s: %s has been authenticated by privileged process", 390 __func__, authctxt->user); 391 392 mm_get_keystate(pmonitor); 393 } 394 395 static void 396 monitor_set_child_handler(pid_t pid) 397 { 398 monitor_child_pid = pid; 399 } 400 401 static void 402 monitor_child_handler(int sig) 403 { 404 kill(monitor_child_pid, sig); 405 } 406 407 void 408 monitor_child_postauth(struct monitor *pmonitor) 409 { 410 monitor_set_child_handler(pmonitor->m_pid); 411 signal(SIGHUP, &monitor_child_handler); 412 signal(SIGTERM, &monitor_child_handler); 413 signal(SIGINT, &monitor_child_handler); 414 415 if (compat20) { 416 mon_dispatch = mon_dispatch_postauth20; 417 418 /* Permit requests for moduli and signatures */ 419 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 420 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 421 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 422 } else { 423 mon_dispatch = mon_dispatch_postauth15; 424 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 425 } 426 if (!no_pty_flag) { 427 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 428 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 429 } 430 431 for (;;) 432 monitor_read(pmonitor, mon_dispatch, NULL); 433 } 434 435 void 436 monitor_sync(struct monitor *pmonitor) 437 { 438 if (options.compression) { 439 /* The member allocation is not visible, so sync it */ 440 mm_share_sync(&pmonitor->m_zlib, &pmonitor->m_zback); 441 } 442 } 443 444 int 445 monitor_read(struct monitor *pmonitor, struct mon_table *ent, 446 struct mon_table **pent) 447 { 448 Buffer m; 449 int ret; 450 u_char type; 451 452 buffer_init(&m); 453 454 mm_request_receive(pmonitor->m_sendfd, &m); 455 type = buffer_get_char(&m); 456 457 debug3("%s: checking request %d", __func__, type); 458 459 while (ent->f != NULL) { 460 if (ent->type == type) 461 break; 462 ent++; 463 } 464 465 if (ent->f != NULL) { 466 if (!(ent->flags & MON_PERMIT)) 467 fatal("%s: unpermitted request %d", __func__, 468 type); 469 ret = (*ent->f)(pmonitor->m_sendfd, &m); 470 buffer_free(&m); 471 472 /* The child may use this request only once, disable it */ 473 if (ent->flags & MON_ONCE) { 474 debug2("%s: %d used once, disabling now", __func__, 475 type); 476 ent->flags &= ~MON_PERMIT; 477 } 478 479 if (pent != NULL) 480 *pent = ent; 481 482 return ret; 483 } 484 485 fatal("%s: unsupported request: %d", __func__, type); 486 487 /* NOTREACHED */ 488 return (-1); 489 } 490 491 /* allowed key state */ 492 static int 493 monitor_allowed_key(u_char *blob, u_int bloblen) 494 { 495 /* make sure key is allowed */ 496 if (key_blob == NULL || key_bloblen != bloblen || 497 memcmp(key_blob, blob, key_bloblen)) 498 return (0); 499 return (1); 500 } 501 502 static void 503 monitor_reset_key_state(void) 504 { 505 /* reset state */ 506 if (key_blob != NULL) 507 xfree(key_blob); 508 if (hostbased_cuser != NULL) 509 xfree(hostbased_cuser); 510 if (hostbased_chost != NULL) 511 xfree(hostbased_chost); 512 key_blob = NULL; 513 key_bloblen = 0; 514 key_blobtype = MM_NOKEY; 515 hostbased_cuser = NULL; 516 hostbased_chost = NULL; 517 } 518 519 int 520 mm_answer_moduli(int sock, Buffer *m) 521 { 522 DH *dh; 523 int min, want, max; 524 525 min = buffer_get_int(m); 526 want = buffer_get_int(m); 527 max = buffer_get_int(m); 528 529 debug3("%s: got parameters: %d %d %d", 530 __func__, min, want, max); 531 /* We need to check here, too, in case the child got corrupted */ 532 if (max < min || want < min || max < want) 533 fatal("%s: bad parameters: %d %d %d", 534 __func__, min, want, max); 535 536 buffer_clear(m); 537 538 dh = choose_dh(min, want, max); 539 if (dh == NULL) { 540 buffer_put_char(m, 0); 541 return (0); 542 } else { 543 /* Send first bignum */ 544 buffer_put_char(m, 1); 545 buffer_put_bignum2(m, dh->p); 546 buffer_put_bignum2(m, dh->g); 547 548 DH_free(dh); 549 } 550 mm_request_send(sock, MONITOR_ANS_MODULI, m); 551 return (0); 552 } 553 554 int 555 mm_answer_sign(int sock, Buffer *m) 556 { 557 Key *key; 558 u_char *p; 559 u_char *signature; 560 u_int siglen, datlen; 561 int keyid; 562 563 debug3("%s", __func__); 564 565 keyid = buffer_get_int(m); 566 p = buffer_get_string(m, &datlen); 567 568 /* 569 * Supported KEX types will only return SHA1 (20 byte) or 570 * SHA256 (32 byte) hashes 571 */ 572 if (datlen != 20 && datlen != 32) 573 fatal("%s: data length incorrect: %u", __func__, datlen); 574 575 /* save session id, it will be passed on the first call */ 576 if (session_id2_len == 0) { 577 session_id2_len = datlen; 578 session_id2 = xmalloc(session_id2_len); 579 memcpy(session_id2, p, session_id2_len); 580 } 581 582 if ((key = get_hostkey_by_index(keyid)) == NULL) 583 fatal("%s: no hostkey from index %d", __func__, keyid); 584 if (key_sign(key, &signature, &siglen, p, datlen) < 0) 585 fatal("%s: key_sign failed", __func__); 586 587 debug3("%s: signature %p(%u)", __func__, signature, siglen); 588 589 buffer_clear(m); 590 buffer_put_string(m, signature, siglen); 591 592 xfree(p); 593 xfree(signature); 594 595 mm_request_send(sock, MONITOR_ANS_SIGN, m); 596 597 /* Turn on permissions for getpwnam */ 598 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 599 600 return (0); 601 } 602 603 /* Retrieves the password entry and also checks if the user is permitted */ 604 605 int 606 mm_answer_pwnamallow(int sock, Buffer *m) 607 { 608 char *username; 609 struct passwd *pwent; 610 int allowed = 0; 611 612 debug3("%s", __func__); 613 614 if (authctxt->attempt++ != 0) 615 fatal("%s: multiple attempts for getpwnam", __func__); 616 617 username = buffer_get_string(m, NULL); 618 619 pwent = getpwnamallow(username); 620 621 authctxt->user = xstrdup(username); 622 setproctitle("%s [priv]", pwent ? username : "unknown"); 623 xfree(username); 624 625 buffer_clear(m); 626 627 if (pwent == NULL) { 628 buffer_put_char(m, 0); 629 authctxt->pw = fakepw(); 630 goto out; 631 } 632 633 allowed = 1; 634 authctxt->pw = pwent; 635 authctxt->valid = 1; 636 637 buffer_put_char(m, 1); 638 buffer_put_string(m, pwent, sizeof(struct passwd)); 639 buffer_put_cstring(m, pwent->pw_name); 640 buffer_put_cstring(m, "*"); 641 buffer_put_cstring(m, pwent->pw_gecos); 642 #ifdef HAVE_PW_CLASS_IN_PASSWD 643 buffer_put_cstring(m, pwent->pw_class); 644 #endif 645 buffer_put_cstring(m, pwent->pw_dir); 646 buffer_put_cstring(m, pwent->pw_shell); 647 648 out: 649 buffer_put_string(m, &options, sizeof(options)); 650 if (options.banner != NULL) 651 buffer_put_cstring(m, options.banner); 652 debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed); 653 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 654 655 /* For SSHv1 allow authentication now */ 656 if (!compat20) 657 monitor_permit_authentications(1); 658 else { 659 /* Allow service/style information on the auth context */ 660 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 661 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 662 } 663 664 #ifdef USE_PAM 665 if (options.use_pam) 666 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); 667 #endif 668 669 return (0); 670 } 671 672 int mm_answer_auth2_read_banner(int sock, Buffer *m) 673 { 674 char *banner; 675 676 buffer_clear(m); 677 banner = auth2_read_banner(); 678 buffer_put_cstring(m, banner != NULL ? banner : ""); 679 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 680 681 if (banner != NULL) 682 xfree(banner); 683 684 return (0); 685 } 686 687 int 688 mm_answer_authserv(int sock, Buffer *m) 689 { 690 monitor_permit_authentications(1); 691 692 authctxt->service = buffer_get_string(m, NULL); 693 authctxt->style = buffer_get_string(m, NULL); 694 debug3("%s: service=%s, style=%s", 695 __func__, authctxt->service, authctxt->style); 696 697 if (strlen(authctxt->style) == 0) { 698 xfree(authctxt->style); 699 authctxt->style = NULL; 700 } 701 702 return (0); 703 } 704 705 int 706 mm_answer_authpassword(int sock, Buffer *m) 707 { 708 static int call_count; 709 char *passwd; 710 int authenticated; 711 u_int plen; 712 713 passwd = buffer_get_string(m, &plen); 714 /* Only authenticate if the context is valid */ 715 authenticated = options.password_authentication && 716 auth_password(authctxt, passwd); 717 memset(passwd, 0, strlen(passwd)); 718 xfree(passwd); 719 720 buffer_clear(m); 721 buffer_put_int(m, authenticated); 722 723 debug3("%s: sending result %d", __func__, authenticated); 724 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 725 726 call_count++; 727 if (plen == 0 && call_count == 1) 728 auth_method = "none"; 729 else 730 auth_method = "password"; 731 732 /* Causes monitor loop to terminate if authenticated */ 733 return (authenticated); 734 } 735 736 #ifdef BSD_AUTH 737 int 738 mm_answer_bsdauthquery(int sock, Buffer *m) 739 { 740 char *name, *infotxt; 741 u_int numprompts; 742 u_int *echo_on; 743 char **prompts; 744 u_int success; 745 746 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 747 &prompts, &echo_on) < 0 ? 0 : 1; 748 749 buffer_clear(m); 750 buffer_put_int(m, success); 751 if (success) 752 buffer_put_cstring(m, prompts[0]); 753 754 debug3("%s: sending challenge success: %u", __func__, success); 755 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 756 757 if (success) { 758 xfree(name); 759 xfree(infotxt); 760 xfree(prompts); 761 xfree(echo_on); 762 } 763 764 return (0); 765 } 766 767 int 768 mm_answer_bsdauthrespond(int sock, Buffer *m) 769 { 770 char *response; 771 int authok; 772 773 if (authctxt->as == 0) 774 fatal("%s: no bsd auth session", __func__); 775 776 response = buffer_get_string(m, NULL); 777 authok = options.challenge_response_authentication && 778 auth_userresponse(authctxt->as, response, 0); 779 authctxt->as = NULL; 780 debug3("%s: <%s> = <%d>", __func__, response, authok); 781 xfree(response); 782 783 buffer_clear(m); 784 buffer_put_int(m, authok); 785 786 debug3("%s: sending authenticated: %d", __func__, authok); 787 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 788 789 auth_method = "bsdauth"; 790 791 return (authok != 0); 792 } 793 #endif 794 795 #ifdef SKEY 796 int 797 mm_answer_skeyquery(int sock, Buffer *m) 798 { 799 struct skey skey; 800 char challenge[1024]; 801 u_int success; 802 803 success = _compat_skeychallenge(&skey, authctxt->user, challenge, 804 sizeof(challenge)) < 0 ? 0 : 1; 805 806 buffer_clear(m); 807 buffer_put_int(m, success); 808 if (success) 809 buffer_put_cstring(m, challenge); 810 811 debug3("%s: sending challenge success: %u", __func__, success); 812 mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m); 813 814 return (0); 815 } 816 817 int 818 mm_answer_skeyrespond(int sock, Buffer *m) 819 { 820 char *response; 821 int authok; 822 823 response = buffer_get_string(m, NULL); 824 825 authok = (options.challenge_response_authentication && 826 authctxt->valid && 827 skey_haskey(authctxt->pw->pw_name) == 0 && 828 skey_passcheck(authctxt->pw->pw_name, response) != -1); 829 830 xfree(response); 831 832 buffer_clear(m); 833 buffer_put_int(m, authok); 834 835 debug3("%s: sending authenticated: %d", __func__, authok); 836 mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m); 837 838 auth_method = "skey"; 839 840 return (authok != 0); 841 } 842 #endif 843 844 #ifdef USE_PAM 845 int 846 mm_answer_pam_start(int sock, Buffer *m) 847 { 848 if (!options.use_pam) 849 fatal("UsePAM not set, but ended up in %s anyway", __func__); 850 851 start_pam(authctxt); 852 853 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); 854 855 return (0); 856 } 857 858 int 859 mm_answer_pam_account(int sock, Buffer *m) 860 { 861 u_int ret; 862 863 if (!options.use_pam) 864 fatal("UsePAM not set, but ended up in %s anyway", __func__); 865 866 ret = do_pam_account(); 867 868 buffer_put_int(m, ret); 869 buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg)); 870 871 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m); 872 873 return (ret); 874 } 875 876 static void *sshpam_ctxt, *sshpam_authok; 877 extern KbdintDevice sshpam_device; 878 879 int 880 mm_answer_pam_init_ctx(int sock, Buffer *m) 881 { 882 883 debug3("%s", __func__); 884 authctxt->user = buffer_get_string(m, NULL); 885 sshpam_ctxt = (sshpam_device.init_ctx)(authctxt); 886 sshpam_authok = NULL; 887 buffer_clear(m); 888 if (sshpam_ctxt != NULL) { 889 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 890 buffer_put_int(m, 1); 891 } else { 892 buffer_put_int(m, 0); 893 } 894 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); 895 return (0); 896 } 897 898 int 899 mm_answer_pam_query(int sock, Buffer *m) 900 { 901 char *name, *info, **prompts; 902 u_int i, num, *echo_on; 903 int ret; 904 905 debug3("%s", __func__); 906 sshpam_authok = NULL; 907 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, &num, &prompts, &echo_on); 908 if (ret == 0 && num == 0) 909 sshpam_authok = sshpam_ctxt; 910 if (num > 1 || name == NULL || info == NULL) 911 ret = -1; 912 buffer_clear(m); 913 buffer_put_int(m, ret); 914 buffer_put_cstring(m, name); 915 xfree(name); 916 buffer_put_cstring(m, info); 917 xfree(info); 918 buffer_put_int(m, num); 919 for (i = 0; i < num; ++i) { 920 buffer_put_cstring(m, prompts[i]); 921 xfree(prompts[i]); 922 buffer_put_int(m, echo_on[i]); 923 } 924 if (prompts != NULL) 925 xfree(prompts); 926 if (echo_on != NULL) 927 xfree(echo_on); 928 auth_method = "keyboard-interactive/pam"; 929 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m); 930 return (0); 931 } 932 933 int 934 mm_answer_pam_respond(int sock, Buffer *m) 935 { 936 char **resp; 937 u_int i, num; 938 int ret; 939 940 debug3("%s", __func__); 941 sshpam_authok = NULL; 942 num = buffer_get_int(m); 943 if (num > 0) { 944 resp = xcalloc(num, sizeof(char *)); 945 for (i = 0; i < num; ++i) 946 resp[i] = buffer_get_string(m, NULL); 947 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp); 948 for (i = 0; i < num; ++i) 949 xfree(resp[i]); 950 xfree(resp); 951 } else { 952 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL); 953 } 954 buffer_clear(m); 955 buffer_put_int(m, ret); 956 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m); 957 auth_method = "keyboard-interactive/pam"; 958 if (ret == 0) 959 sshpam_authok = sshpam_ctxt; 960 return (0); 961 } 962 963 int 964 mm_answer_pam_free_ctx(int sock, Buffer *m) 965 { 966 967 debug3("%s", __func__); 968 (sshpam_device.free_ctx)(sshpam_ctxt); 969 buffer_clear(m); 970 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); 971 auth_method = "keyboard-interactive/pam"; 972 return (sshpam_authok == sshpam_ctxt); 973 } 974 #endif 975 976 static void 977 mm_append_debug(Buffer *m) 978 { 979 if (auth_debug_init && buffer_len(&auth_debug)) { 980 debug3("%s: Appending debug messages for child", __func__); 981 buffer_append(m, buffer_ptr(&auth_debug), 982 buffer_len(&auth_debug)); 983 buffer_clear(&auth_debug); 984 } 985 } 986 987 int 988 mm_answer_keyallowed(int sock, Buffer *m) 989 { 990 Key *key; 991 char *cuser, *chost; 992 u_char *blob; 993 u_int bloblen; 994 enum mm_keytype type = 0; 995 int allowed = 0; 996 997 debug3("%s entering", __func__); 998 999 type = buffer_get_int(m); 1000 cuser = buffer_get_string(m, NULL); 1001 chost = buffer_get_string(m, NULL); 1002 blob = buffer_get_string(m, &bloblen); 1003 1004 key = key_from_blob(blob, bloblen); 1005 1006 if ((compat20 && type == MM_RSAHOSTKEY) || 1007 (!compat20 && type != MM_RSAHOSTKEY)) 1008 fatal("%s: key type and protocol mismatch", __func__); 1009 1010 debug3("%s: key_from_blob: %p", __func__, key); 1011 1012 if (key != NULL && authctxt->valid) { 1013 switch (type) { 1014 case MM_USERKEY: 1015 allowed = options.pubkey_authentication && 1016 user_key_allowed(authctxt->pw, key); 1017 auth_method = "publickey"; 1018 if (options.pubkey_authentication && allowed != 1) 1019 auth_clear_options(); 1020 break; 1021 case MM_HOSTKEY: 1022 allowed = options.hostbased_authentication && 1023 hostbased_key_allowed(authctxt->pw, 1024 cuser, chost, key); 1025 auth_method = "hostbased"; 1026 break; 1027 case MM_RSAHOSTKEY: 1028 key->type = KEY_RSA1; /* XXX */ 1029 allowed = options.rhosts_rsa_authentication && 1030 auth_rhosts_rsa_key_allowed(authctxt->pw, 1031 cuser, chost, key); 1032 if (options.rhosts_rsa_authentication && allowed != 1) 1033 auth_clear_options(); 1034 auth_method = "rsa"; 1035 break; 1036 default: 1037 fatal("%s: unknown key type %d", __func__, type); 1038 break; 1039 } 1040 } 1041 if (key != NULL) 1042 key_free(key); 1043 1044 /* clear temporarily storage (used by verify) */ 1045 monitor_reset_key_state(); 1046 1047 if (allowed) { 1048 /* Save temporarily for comparison in verify */ 1049 key_blob = blob; 1050 key_bloblen = bloblen; 1051 key_blobtype = type; 1052 hostbased_cuser = cuser; 1053 hostbased_chost = chost; 1054 } else { 1055 /* Log failed attempt */ 1056 auth_log(authctxt, 0, auth_method, compat20 ? " ssh2" : ""); 1057 xfree(blob); 1058 xfree(cuser); 1059 xfree(chost); 1060 } 1061 1062 debug3("%s: key %p is %s", 1063 __func__, key, allowed ? "allowed" : "not allowed"); 1064 1065 buffer_clear(m); 1066 buffer_put_int(m, allowed); 1067 buffer_put_int(m, forced_command != NULL); 1068 1069 mm_append_debug(m); 1070 1071 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 1072 1073 if (type == MM_RSAHOSTKEY) 1074 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed); 1075 1076 return (0); 1077 } 1078 1079 static int 1080 monitor_valid_userblob(u_char *data, u_int datalen) 1081 { 1082 Buffer b; 1083 char *p; 1084 u_int len; 1085 int fail = 0; 1086 1087 buffer_init(&b); 1088 buffer_append(&b, data, datalen); 1089 1090 if (datafellows & SSH_OLD_SESSIONID) { 1091 p = buffer_ptr(&b); 1092 len = buffer_len(&b); 1093 if ((session_id2 == NULL) || 1094 (len < session_id2_len) || 1095 (memcmp(p, session_id2, session_id2_len) != 0)) 1096 fail++; 1097 buffer_consume(&b, session_id2_len); 1098 } else { 1099 p = buffer_get_string(&b, &len); 1100 if ((session_id2 == NULL) || 1101 (len != session_id2_len) || 1102 (memcmp(p, session_id2, session_id2_len) != 0)) 1103 fail++; 1104 xfree(p); 1105 } 1106 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 1107 fail++; 1108 p = buffer_get_string(&b, NULL); 1109 if (strcmp(authctxt->user, p) != 0) { 1110 logit("wrong user name passed to monitor: expected %s != %.100s", 1111 authctxt->user, p); 1112 fail++; 1113 } 1114 xfree(p); 1115 buffer_skip_string(&b); 1116 if (datafellows & SSH_BUG_PKAUTH) { 1117 if (!buffer_get_char(&b)) 1118 fail++; 1119 } else { 1120 p = buffer_get_string(&b, NULL); 1121 if (strcmp("publickey", p) != 0) 1122 fail++; 1123 xfree(p); 1124 if (!buffer_get_char(&b)) 1125 fail++; 1126 buffer_skip_string(&b); 1127 } 1128 buffer_skip_string(&b); 1129 if (buffer_len(&b) != 0) 1130 fail++; 1131 buffer_free(&b); 1132 return (fail == 0); 1133 } 1134 1135 static int 1136 monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser, 1137 char *chost) 1138 { 1139 Buffer b; 1140 char *p; 1141 u_int len; 1142 int fail = 0; 1143 1144 buffer_init(&b); 1145 buffer_append(&b, data, datalen); 1146 1147 p = buffer_get_string(&b, &len); 1148 if ((session_id2 == NULL) || 1149 (len != session_id2_len) || 1150 (memcmp(p, session_id2, session_id2_len) != 0)) 1151 fail++; 1152 xfree(p); 1153 1154 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 1155 fail++; 1156 p = buffer_get_string(&b, NULL); 1157 if (strcmp(authctxt->user, p) != 0) { 1158 logit("wrong user name passed to monitor: expected %s != %.100s", 1159 authctxt->user, p); 1160 fail++; 1161 } 1162 xfree(p); 1163 buffer_skip_string(&b); /* service */ 1164 p = buffer_get_string(&b, NULL); 1165 if (strcmp(p, "hostbased") != 0) 1166 fail++; 1167 xfree(p); 1168 buffer_skip_string(&b); /* pkalg */ 1169 buffer_skip_string(&b); /* pkblob */ 1170 1171 /* verify client host, strip trailing dot if necessary */ 1172 p = buffer_get_string(&b, NULL); 1173 if (((len = strlen(p)) > 0) && p[len - 1] == '.') 1174 p[len - 1] = '\0'; 1175 if (strcmp(p, chost) != 0) 1176 fail++; 1177 xfree(p); 1178 1179 /* verify client user */ 1180 p = buffer_get_string(&b, NULL); 1181 if (strcmp(p, cuser) != 0) 1182 fail++; 1183 xfree(p); 1184 1185 if (buffer_len(&b) != 0) 1186 fail++; 1187 buffer_free(&b); 1188 return (fail == 0); 1189 } 1190 1191 int 1192 mm_answer_keyverify(int sock, Buffer *m) 1193 { 1194 Key *key; 1195 u_char *signature, *data, *blob; 1196 u_int signaturelen, datalen, bloblen; 1197 int verified = 0; 1198 int valid_data = 0; 1199 1200 blob = buffer_get_string(m, &bloblen); 1201 signature = buffer_get_string(m, &signaturelen); 1202 data = buffer_get_string(m, &datalen); 1203 1204 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1205 !monitor_allowed_key(blob, bloblen)) 1206 fatal("%s: bad key, not previously allowed", __func__); 1207 1208 key = key_from_blob(blob, bloblen); 1209 if (key == NULL) 1210 fatal("%s: bad public key blob", __func__); 1211 1212 switch (key_blobtype) { 1213 case MM_USERKEY: 1214 valid_data = monitor_valid_userblob(data, datalen); 1215 break; 1216 case MM_HOSTKEY: 1217 valid_data = monitor_valid_hostbasedblob(data, datalen, 1218 hostbased_cuser, hostbased_chost); 1219 break; 1220 default: 1221 valid_data = 0; 1222 break; 1223 } 1224 if (!valid_data) 1225 fatal("%s: bad signature data blob", __func__); 1226 1227 verified = key_verify(key, signature, signaturelen, data, datalen); 1228 debug3("%s: key %p signature %s", 1229 __func__, key, (verified == 1) ? "verified" : "unverified"); 1230 1231 key_free(key); 1232 xfree(blob); 1233 xfree(signature); 1234 xfree(data); 1235 1236 auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased"; 1237 1238 monitor_reset_key_state(); 1239 1240 buffer_clear(m); 1241 buffer_put_int(m, verified); 1242 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1243 1244 return (verified == 1); 1245 } 1246 1247 static void 1248 mm_record_login(Session *s, struct passwd *pw) 1249 { 1250 socklen_t fromlen; 1251 struct sockaddr_storage from; 1252 1253 /* 1254 * Get IP address of client. If the connection is not a socket, let 1255 * the address be 0.0.0.0. 1256 */ 1257 memset(&from, 0, sizeof(from)); 1258 fromlen = sizeof(from); 1259 if (packet_connection_is_on_socket()) { 1260 if (getpeername(packet_get_connection_in(), 1261 (struct sockaddr *)&from, &fromlen) < 0) { 1262 debug("getpeername: %.100s", strerror(errno)); 1263 cleanup_exit(255); 1264 } 1265 } 1266 /* Record that there was a login on that tty from the remote host. */ 1267 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1268 get_remote_name_or_ip(utmp_len, options.use_dns), 1269 (struct sockaddr *)&from, fromlen); 1270 } 1271 1272 static void 1273 mm_session_close(Session *s) 1274 { 1275 debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid); 1276 if (s->ttyfd != -1) { 1277 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd); 1278 session_pty_cleanup2(s); 1279 } 1280 session_unused(s->self); 1281 } 1282 1283 int 1284 mm_answer_pty(int sock, Buffer *m) 1285 { 1286 extern struct monitor *pmonitor; 1287 Session *s; 1288 int res, fd0; 1289 1290 debug3("%s entering", __func__); 1291 1292 buffer_clear(m); 1293 s = session_new(); 1294 if (s == NULL) 1295 goto error; 1296 s->authctxt = authctxt; 1297 s->pw = authctxt->pw; 1298 s->pid = pmonitor->m_pid; 1299 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1300 if (res == 0) 1301 goto error; 1302 pty_setowner(authctxt->pw, s->tty); 1303 1304 buffer_put_int(m, 1); 1305 buffer_put_cstring(m, s->tty); 1306 1307 /* We need to trick ttyslot */ 1308 if (dup2(s->ttyfd, 0) == -1) 1309 fatal("%s: dup2", __func__); 1310 1311 mm_record_login(s, authctxt->pw); 1312 1313 /* Now we can close the file descriptor again */ 1314 close(0); 1315 1316 /* send messages generated by record_login */ 1317 buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg)); 1318 buffer_clear(&loginmsg); 1319 1320 mm_request_send(sock, MONITOR_ANS_PTY, m); 1321 1322 if (mm_send_fd(sock, s->ptyfd) == -1 || 1323 mm_send_fd(sock, s->ttyfd) == -1) 1324 fatal("%s: send fds failed", __func__); 1325 1326 /* make sure nothing uses fd 0 */ 1327 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0) 1328 fatal("%s: open(/dev/null): %s", __func__, strerror(errno)); 1329 if (fd0 != 0) 1330 error("%s: fd0 %d != 0", __func__, fd0); 1331 1332 /* slave is not needed */ 1333 close(s->ttyfd); 1334 s->ttyfd = s->ptyfd; 1335 /* no need to dup() because nobody closes ptyfd */ 1336 s->ptymaster = s->ptyfd; 1337 1338 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd); 1339 1340 return (0); 1341 1342 error: 1343 if (s != NULL) 1344 mm_session_close(s); 1345 buffer_put_int(m, 0); 1346 mm_request_send(sock, MONITOR_ANS_PTY, m); 1347 return (0); 1348 } 1349 1350 int 1351 mm_answer_pty_cleanup(int sock, Buffer *m) 1352 { 1353 Session *s; 1354 char *tty; 1355 1356 debug3("%s entering", __func__); 1357 1358 tty = buffer_get_string(m, NULL); 1359 if ((s = session_by_tty(tty)) != NULL) 1360 mm_session_close(s); 1361 buffer_clear(m); 1362 xfree(tty); 1363 return (0); 1364 } 1365 1366 int 1367 mm_answer_sesskey(int sock, Buffer *m) 1368 { 1369 BIGNUM *p; 1370 int rsafail; 1371 1372 /* Turn off permissions */ 1373 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 0); 1374 1375 if ((p = BN_new()) == NULL) 1376 fatal("%s: BN_new", __func__); 1377 1378 buffer_get_bignum2(m, p); 1379 1380 rsafail = ssh1_session_key(p); 1381 1382 buffer_clear(m); 1383 buffer_put_int(m, rsafail); 1384 buffer_put_bignum2(m, p); 1385 1386 BN_clear_free(p); 1387 1388 mm_request_send(sock, MONITOR_ANS_SESSKEY, m); 1389 1390 /* Turn on permissions for sessid passing */ 1391 monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1); 1392 1393 return (0); 1394 } 1395 1396 int 1397 mm_answer_sessid(int sock, Buffer *m) 1398 { 1399 int i; 1400 1401 debug3("%s entering", __func__); 1402 1403 if (buffer_len(m) != 16) 1404 fatal("%s: bad ssh1 session id", __func__); 1405 for (i = 0; i < 16; i++) 1406 session_id[i] = buffer_get_char(m); 1407 1408 /* Turn on permissions for getpwnam */ 1409 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 1410 1411 return (0); 1412 } 1413 1414 int 1415 mm_answer_rsa_keyallowed(int sock, Buffer *m) 1416 { 1417 BIGNUM *client_n; 1418 Key *key = NULL; 1419 u_char *blob = NULL; 1420 u_int blen = 0; 1421 int allowed = 0; 1422 1423 debug3("%s entering", __func__); 1424 1425 auth_method = "rsa"; 1426 if (options.rsa_authentication && authctxt->valid) { 1427 if ((client_n = BN_new()) == NULL) 1428 fatal("%s: BN_new", __func__); 1429 buffer_get_bignum2(m, client_n); 1430 allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key); 1431 BN_clear_free(client_n); 1432 } 1433 buffer_clear(m); 1434 buffer_put_int(m, allowed); 1435 buffer_put_int(m, forced_command != NULL); 1436 1437 /* clear temporarily storage (used by generate challenge) */ 1438 monitor_reset_key_state(); 1439 1440 if (allowed && key != NULL) { 1441 key->type = KEY_RSA; /* cheat for key_to_blob */ 1442 if (key_to_blob(key, &blob, &blen) == 0) 1443 fatal("%s: key_to_blob failed", __func__); 1444 buffer_put_string(m, blob, blen); 1445 1446 /* Save temporarily for comparison in verify */ 1447 key_blob = blob; 1448 key_bloblen = blen; 1449 key_blobtype = MM_RSAUSERKEY; 1450 } 1451 if (key != NULL) 1452 key_free(key); 1453 1454 mm_append_debug(m); 1455 1456 mm_request_send(sock, MONITOR_ANS_RSAKEYALLOWED, m); 1457 1458 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed); 1459 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0); 1460 return (0); 1461 } 1462 1463 int 1464 mm_answer_rsa_challenge(int sock, Buffer *m) 1465 { 1466 Key *key = NULL; 1467 u_char *blob; 1468 u_int blen; 1469 1470 debug3("%s entering", __func__); 1471 1472 if (!authctxt->valid) 1473 fatal("%s: authctxt not valid", __func__); 1474 blob = buffer_get_string(m, &blen); 1475 if (!monitor_allowed_key(blob, blen)) 1476 fatal("%s: bad key, not previously allowed", __func__); 1477 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) 1478 fatal("%s: key type mismatch", __func__); 1479 if ((key = key_from_blob(blob, blen)) == NULL) 1480 fatal("%s: received bad key", __func__); 1481 1482 if (ssh1_challenge) 1483 BN_clear_free(ssh1_challenge); 1484 ssh1_challenge = auth_rsa_generate_challenge(key); 1485 1486 buffer_clear(m); 1487 buffer_put_bignum2(m, ssh1_challenge); 1488 1489 debug3("%s sending reply", __func__); 1490 mm_request_send(sock, MONITOR_ANS_RSACHALLENGE, m); 1491 1492 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1); 1493 1494 xfree(blob); 1495 key_free(key); 1496 return (0); 1497 } 1498 1499 int 1500 mm_answer_rsa_response(int sock, Buffer *m) 1501 { 1502 Key *key = NULL; 1503 u_char *blob, *response; 1504 u_int blen, len; 1505 int success; 1506 1507 debug3("%s entering", __func__); 1508 1509 if (!authctxt->valid) 1510 fatal("%s: authctxt not valid", __func__); 1511 if (ssh1_challenge == NULL) 1512 fatal("%s: no ssh1_challenge", __func__); 1513 1514 blob = buffer_get_string(m, &blen); 1515 if (!monitor_allowed_key(blob, blen)) 1516 fatal("%s: bad key, not previously allowed", __func__); 1517 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) 1518 fatal("%s: key type mismatch: %d", __func__, key_blobtype); 1519 if ((key = key_from_blob(blob, blen)) == NULL) 1520 fatal("%s: received bad key", __func__); 1521 response = buffer_get_string(m, &len); 1522 if (len != 16) 1523 fatal("%s: received bad response to challenge", __func__); 1524 success = auth_rsa_verify_response(key, ssh1_challenge, response); 1525 1526 xfree(blob); 1527 key_free(key); 1528 xfree(response); 1529 1530 auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa"; 1531 1532 /* reset state */ 1533 BN_clear_free(ssh1_challenge); 1534 ssh1_challenge = NULL; 1535 monitor_reset_key_state(); 1536 1537 buffer_clear(m); 1538 buffer_put_int(m, success); 1539 mm_request_send(sock, MONITOR_ANS_RSARESPONSE, m); 1540 1541 return (success); 1542 } 1543 1544 int 1545 mm_answer_term(int sock, Buffer *req) 1546 { 1547 extern struct monitor *pmonitor; 1548 int res, status; 1549 1550 debug3("%s: tearing down sessions", __func__); 1551 1552 /* The child is terminating */ 1553 session_destroy_all(&mm_session_close); 1554 1555 #ifdef USE_PAM 1556 if (options.use_pam) 1557 sshpam_cleanup(); 1558 #endif 1559 1560 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1561 if (errno != EINTR) 1562 exit(1); 1563 1564 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1565 1566 /* Terminate process */ 1567 exit(res); 1568 } 1569 1570 #ifdef SSH_AUDIT_EVENTS 1571 /* Report that an audit event occurred */ 1572 int 1573 mm_answer_audit_event(int socket, Buffer *m) 1574 { 1575 ssh_audit_event_t event; 1576 1577 debug3("%s entering", __func__); 1578 1579 event = buffer_get_int(m); 1580 switch(event) { 1581 case SSH_AUTH_FAIL_PUBKEY: 1582 case SSH_AUTH_FAIL_HOSTBASED: 1583 case SSH_AUTH_FAIL_GSSAPI: 1584 case SSH_LOGIN_EXCEED_MAXTRIES: 1585 case SSH_LOGIN_ROOT_DENIED: 1586 case SSH_CONNECTION_CLOSE: 1587 case SSH_INVALID_USER: 1588 audit_event(event); 1589 break; 1590 default: 1591 fatal("Audit event type %d not permitted", event); 1592 } 1593 1594 return (0); 1595 } 1596 1597 int 1598 mm_answer_audit_command(int socket, Buffer *m) 1599 { 1600 u_int len; 1601 char *cmd; 1602 1603 debug3("%s entering", __func__); 1604 cmd = buffer_get_string(m, &len); 1605 /* sanity check command, if so how? */ 1606 audit_run_command(cmd); 1607 xfree(cmd); 1608 return (0); 1609 } 1610 #endif /* SSH_AUDIT_EVENTS */ 1611 1612 void 1613 monitor_apply_keystate(struct monitor *pmonitor) 1614 { 1615 if (compat20) { 1616 set_newkeys(MODE_IN); 1617 set_newkeys(MODE_OUT); 1618 } else { 1619 packet_set_protocol_flags(child_state.ssh1protoflags); 1620 packet_set_encryption_key(child_state.ssh1key, 1621 child_state.ssh1keylen, child_state.ssh1cipher); 1622 xfree(child_state.ssh1key); 1623 } 1624 1625 /* for rc4 and other stateful ciphers */ 1626 packet_set_keycontext(MODE_OUT, child_state.keyout); 1627 xfree(child_state.keyout); 1628 packet_set_keycontext(MODE_IN, child_state.keyin); 1629 xfree(child_state.keyin); 1630 1631 if (!compat20) { 1632 packet_set_iv(MODE_OUT, child_state.ivout); 1633 xfree(child_state.ivout); 1634 packet_set_iv(MODE_IN, child_state.ivin); 1635 xfree(child_state.ivin); 1636 } 1637 1638 memcpy(&incoming_stream, &child_state.incoming, 1639 sizeof(incoming_stream)); 1640 memcpy(&outgoing_stream, &child_state.outgoing, 1641 sizeof(outgoing_stream)); 1642 1643 /* Update with new address */ 1644 if (options.compression) 1645 mm_init_compression(pmonitor->m_zlib); 1646 1647 /* Network I/O buffers */ 1648 /* XXX inefficient for large buffers, need: buffer_init_from_string */ 1649 buffer_clear(&input); 1650 buffer_append(&input, child_state.input, child_state.ilen); 1651 memset(child_state.input, 0, child_state.ilen); 1652 xfree(child_state.input); 1653 1654 buffer_clear(&output); 1655 buffer_append(&output, child_state.output, child_state.olen); 1656 memset(child_state.output, 0, child_state.olen); 1657 xfree(child_state.output); 1658 } 1659 1660 static Kex * 1661 mm_get_kex(Buffer *m) 1662 { 1663 Kex *kex; 1664 void *blob; 1665 u_int bloblen; 1666 1667 kex = xcalloc(1, sizeof(*kex)); 1668 kex->session_id = buffer_get_string(m, &kex->session_id_len); 1669 if ((session_id2 == NULL) || 1670 (kex->session_id_len != session_id2_len) || 1671 (memcmp(kex->session_id, session_id2, session_id2_len) != 0)) 1672 fatal("mm_get_get: internal error: bad session id"); 1673 kex->we_need = buffer_get_int(m); 1674 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; 1675 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; 1676 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1677 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1678 kex->server = 1; 1679 kex->hostkey_type = buffer_get_int(m); 1680 kex->kex_type = buffer_get_int(m); 1681 blob = buffer_get_string(m, &bloblen); 1682 buffer_init(&kex->my); 1683 buffer_append(&kex->my, blob, bloblen); 1684 xfree(blob); 1685 blob = buffer_get_string(m, &bloblen); 1686 buffer_init(&kex->peer); 1687 buffer_append(&kex->peer, blob, bloblen); 1688 xfree(blob); 1689 kex->done = 1; 1690 kex->flags = buffer_get_int(m); 1691 kex->client_version_string = buffer_get_string(m, NULL); 1692 kex->server_version_string = buffer_get_string(m, NULL); 1693 kex->load_host_key=&get_hostkey_by_type; 1694 kex->host_key_index=&get_hostkey_index; 1695 1696 return (kex); 1697 } 1698 1699 /* This function requries careful sanity checking */ 1700 1701 void 1702 mm_get_keystate(struct monitor *pmonitor) 1703 { 1704 Buffer m; 1705 u_char *blob, *p; 1706 u_int bloblen, plen; 1707 u_int32_t seqnr, packets; 1708 u_int64_t blocks, bytes; 1709 1710 debug3("%s: Waiting for new keys", __func__); 1711 1712 buffer_init(&m); 1713 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, &m); 1714 if (!compat20) { 1715 child_state.ssh1protoflags = buffer_get_int(&m); 1716 child_state.ssh1cipher = buffer_get_int(&m); 1717 child_state.ssh1key = buffer_get_string(&m, 1718 &child_state.ssh1keylen); 1719 child_state.ivout = buffer_get_string(&m, 1720 &child_state.ivoutlen); 1721 child_state.ivin = buffer_get_string(&m, &child_state.ivinlen); 1722 goto skip; 1723 } else { 1724 /* Get the Kex for rekeying */ 1725 *pmonitor->m_pkex = mm_get_kex(&m); 1726 } 1727 1728 blob = buffer_get_string(&m, &bloblen); 1729 current_keys[MODE_OUT] = mm_newkeys_from_blob(blob, bloblen); 1730 xfree(blob); 1731 1732 debug3("%s: Waiting for second key", __func__); 1733 blob = buffer_get_string(&m, &bloblen); 1734 current_keys[MODE_IN] = mm_newkeys_from_blob(blob, bloblen); 1735 xfree(blob); 1736 1737 /* Now get sequence numbers for the packets */ 1738 seqnr = buffer_get_int(&m); 1739 blocks = buffer_get_int64(&m); 1740 packets = buffer_get_int(&m); 1741 bytes = buffer_get_int64(&m); 1742 packet_set_state(MODE_OUT, seqnr, blocks, packets, bytes); 1743 seqnr = buffer_get_int(&m); 1744 blocks = buffer_get_int64(&m); 1745 packets = buffer_get_int(&m); 1746 bytes = buffer_get_int64(&m); 1747 packet_set_state(MODE_IN, seqnr, blocks, packets, bytes); 1748 1749 skip: 1750 /* Get the key context */ 1751 child_state.keyout = buffer_get_string(&m, &child_state.keyoutlen); 1752 child_state.keyin = buffer_get_string(&m, &child_state.keyinlen); 1753 1754 debug3("%s: Getting compression state", __func__); 1755 /* Get compression state */ 1756 p = buffer_get_string(&m, &plen); 1757 if (plen != sizeof(child_state.outgoing)) 1758 fatal("%s: bad request size", __func__); 1759 memcpy(&child_state.outgoing, p, sizeof(child_state.outgoing)); 1760 xfree(p); 1761 1762 p = buffer_get_string(&m, &plen); 1763 if (plen != sizeof(child_state.incoming)) 1764 fatal("%s: bad request size", __func__); 1765 memcpy(&child_state.incoming, p, sizeof(child_state.incoming)); 1766 xfree(p); 1767 1768 /* Network I/O buffers */ 1769 debug3("%s: Getting Network I/O buffers", __func__); 1770 child_state.input = buffer_get_string(&m, &child_state.ilen); 1771 child_state.output = buffer_get_string(&m, &child_state.olen); 1772 1773 buffer_free(&m); 1774 } 1775 1776 1777 /* Allocation functions for zlib */ 1778 void * 1779 mm_zalloc(struct mm_master *mm, u_int ncount, u_int size) 1780 { 1781 size_t len = (size_t) size * ncount; 1782 void *address; 1783 1784 if (len == 0 || ncount > SIZE_T_MAX / size) 1785 fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size); 1786 1787 address = mm_malloc(mm, len); 1788 1789 return (address); 1790 } 1791 1792 void 1793 mm_zfree(struct mm_master *mm, void *address) 1794 { 1795 mm_free(mm, address); 1796 } 1797 1798 void 1799 mm_init_compression(struct mm_master *mm) 1800 { 1801 outgoing_stream.zalloc = (alloc_func)mm_zalloc; 1802 outgoing_stream.zfree = (free_func)mm_zfree; 1803 outgoing_stream.opaque = mm; 1804 1805 incoming_stream.zalloc = (alloc_func)mm_zalloc; 1806 incoming_stream.zfree = (free_func)mm_zfree; 1807 incoming_stream.opaque = mm; 1808 } 1809 1810 /* XXX */ 1811 1812 #define FD_CLOSEONEXEC(x) do { \ 1813 if (fcntl(x, F_SETFD, 1) == -1) \ 1814 fatal("fcntl(%d, F_SETFD)", x); \ 1815 } while (0) 1816 1817 static void 1818 monitor_socketpair(int *pair) 1819 { 1820 #ifdef HAVE_SOCKETPAIR 1821 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1822 fatal("%s: socketpair", __func__); 1823 #else 1824 fatal("%s: UsePrivilegeSeparation=yes not supported", 1825 __func__); 1826 #endif 1827 FD_CLOSEONEXEC(pair[0]); 1828 FD_CLOSEONEXEC(pair[1]); 1829 } 1830 1831 #define MM_MEMSIZE 65536 1832 1833 struct monitor * 1834 monitor_init(void) 1835 { 1836 struct monitor *mon; 1837 int pair[2]; 1838 1839 mon = xcalloc(1, sizeof(*mon)); 1840 1841 monitor_socketpair(pair); 1842 1843 mon->m_recvfd = pair[0]; 1844 mon->m_sendfd = pair[1]; 1845 1846 /* Used to share zlib space across processes */ 1847 if (options.compression) { 1848 mon->m_zback = mm_create(NULL, MM_MEMSIZE); 1849 mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE); 1850 1851 /* Compression needs to share state across borders */ 1852 mm_init_compression(mon->m_zlib); 1853 } 1854 1855 return mon; 1856 } 1857 1858 void 1859 monitor_reinit(struct monitor *mon) 1860 { 1861 int pair[2]; 1862 1863 monitor_socketpair(pair); 1864 1865 mon->m_recvfd = pair[0]; 1866 mon->m_sendfd = pair[1]; 1867 } 1868 1869 #ifdef GSSAPI 1870 int 1871 mm_answer_gss_setup_ctx(int sock, Buffer *m) 1872 { 1873 gss_OID_desc goid; 1874 OM_uint32 major; 1875 u_int len; 1876 1877 goid.elements = buffer_get_string(m, &len); 1878 goid.length = len; 1879 1880 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1881 1882 xfree(goid.elements); 1883 1884 buffer_clear(m); 1885 buffer_put_int(m, major); 1886 1887 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1888 1889 /* Now we have a context, enable the step */ 1890 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1891 1892 return (0); 1893 } 1894 1895 int 1896 mm_answer_gss_accept_ctx(int sock, Buffer *m) 1897 { 1898 gss_buffer_desc in; 1899 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1900 OM_uint32 major, minor; 1901 OM_uint32 flags = 0; /* GSI needs this */ 1902 u_int len; 1903 1904 in.value = buffer_get_string(m, &len); 1905 in.length = len; 1906 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1907 xfree(in.value); 1908 1909 buffer_clear(m); 1910 buffer_put_int(m, major); 1911 buffer_put_string(m, out.value, out.length); 1912 buffer_put_int(m, flags); 1913 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1914 1915 gss_release_buffer(&minor, &out); 1916 1917 if (major == GSS_S_COMPLETE) { 1918 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1919 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1920 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1921 } 1922 return (0); 1923 } 1924 1925 int 1926 mm_answer_gss_checkmic(int sock, Buffer *m) 1927 { 1928 gss_buffer_desc gssbuf, mic; 1929 OM_uint32 ret; 1930 u_int len; 1931 1932 gssbuf.value = buffer_get_string(m, &len); 1933 gssbuf.length = len; 1934 mic.value = buffer_get_string(m, &len); 1935 mic.length = len; 1936 1937 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1938 1939 xfree(gssbuf.value); 1940 xfree(mic.value); 1941 1942 buffer_clear(m); 1943 buffer_put_int(m, ret); 1944 1945 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1946 1947 if (!GSS_ERROR(ret)) 1948 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1949 1950 return (0); 1951 } 1952 1953 int 1954 mm_answer_gss_userok(int sock, Buffer *m) 1955 { 1956 int authenticated; 1957 1958 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1959 1960 buffer_clear(m); 1961 buffer_put_int(m, authenticated); 1962 1963 debug3("%s: sending result %d", __func__, authenticated); 1964 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1965 1966 auth_method = "gssapi-with-mic"; 1967 1968 /* Monitor loop will terminate if authenticated */ 1969 return (authenticated); 1970 } 1971 #endif /* GSSAPI */ 1972