1 /* $OpenBSD: monitor.c,v 1.89 2006/11/07 10:31:31 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 __RCSID("$FreeBSD$"); 30 31 #include <sys/types.h> 32 #include <sys/param.h> 33 #include <sys/socket.h> 34 #include "openbsd-compat/sys-tree.h" 35 #include <sys/wait.h> 36 37 #include <errno.h> 38 #include <fcntl.h> 39 #ifdef HAVE_PATHS_H 40 #include <paths.h> 41 #endif 42 #include <pwd.h> 43 #include <signal.h> 44 #include <stdarg.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include <unistd.h> 48 49 #ifdef SKEY 50 #ifdef OPIE 51 #include <opie.h> 52 #define skey opie 53 #define skeychallenge(k, u, c) opiechallenge((k), (u), (c)) 54 #define skey_haskey(u) opie_haskey((u)) 55 #define skey_passcheck(u, r) opie_passverify((u), (r)) 56 #else 57 #include <skey.h> 58 #endif 59 #endif 60 61 #include <openssl/dh.h> 62 63 #include "xmalloc.h" 64 #include "ssh.h" 65 #include "key.h" 66 #include "buffer.h" 67 #include "hostfile.h" 68 #include "auth.h" 69 #include "cipher.h" 70 #include "kex.h" 71 #include "dh.h" 72 #ifdef TARGET_OS_MAC /* XXX Broken krb5 headers on Mac */ 73 #undef TARGET_OS_MAC 74 #include "zlib.h" 75 #define TARGET_OS_MAC 1 76 #else 77 #include "zlib.h" 78 #endif 79 #include "packet.h" 80 #include "auth-options.h" 81 #include "sshpty.h" 82 #include "channels.h" 83 #include "session.h" 84 #include "sshlogin.h" 85 #include "canohost.h" 86 #include "log.h" 87 #include "servconf.h" 88 #include "monitor.h" 89 #include "monitor_mm.h" 90 #ifdef GSSAPI 91 #include "ssh-gss.h" 92 #endif 93 #include "monitor_wrap.h" 94 #include "monitor_fdpass.h" 95 #include "misc.h" 96 #include "compat.h" 97 #include "ssh2.h" 98 99 #ifdef GSSAPI 100 static Gssctxt *gsscontext = NULL; 101 #endif 102 103 /* Imports */ 104 extern ServerOptions options; 105 extern u_int utmp_len; 106 extern Newkeys *current_keys[]; 107 extern z_stream incoming_stream; 108 extern z_stream outgoing_stream; 109 extern u_char session_id[]; 110 extern Buffer input, output; 111 extern Buffer auth_debug; 112 extern int auth_debug_init; 113 extern Buffer loginmsg; 114 115 /* State exported from the child */ 116 117 struct { 118 z_stream incoming; 119 z_stream outgoing; 120 u_char *keyin; 121 u_int keyinlen; 122 u_char *keyout; 123 u_int keyoutlen; 124 u_char *ivin; 125 u_int ivinlen; 126 u_char *ivout; 127 u_int ivoutlen; 128 u_char *ssh1key; 129 u_int ssh1keylen; 130 int ssh1cipher; 131 int ssh1protoflags; 132 u_char *input; 133 u_int ilen; 134 u_char *output; 135 u_int olen; 136 } child_state; 137 138 /* Functions on the monitor that answer unprivileged requests */ 139 140 int mm_answer_moduli(int, Buffer *); 141 int mm_answer_sign(int, Buffer *); 142 int mm_answer_pwnamallow(int, Buffer *); 143 int mm_answer_auth2_read_banner(int, Buffer *); 144 int mm_answer_authserv(int, Buffer *); 145 int mm_answer_authpassword(int, Buffer *); 146 int mm_answer_bsdauthquery(int, Buffer *); 147 int mm_answer_bsdauthrespond(int, Buffer *); 148 int mm_answer_skeyquery(int, Buffer *); 149 int mm_answer_skeyrespond(int, Buffer *); 150 int mm_answer_keyallowed(int, Buffer *); 151 int mm_answer_keyverify(int, Buffer *); 152 int mm_answer_pty(int, Buffer *); 153 int mm_answer_pty_cleanup(int, Buffer *); 154 int mm_answer_term(int, Buffer *); 155 int mm_answer_rsa_keyallowed(int, Buffer *); 156 int mm_answer_rsa_challenge(int, Buffer *); 157 int mm_answer_rsa_response(int, Buffer *); 158 int mm_answer_sesskey(int, Buffer *); 159 int mm_answer_sessid(int, Buffer *); 160 161 #ifdef USE_PAM 162 int mm_answer_pam_start(int, Buffer *); 163 int mm_answer_pam_account(int, Buffer *); 164 int mm_answer_pam_init_ctx(int, Buffer *); 165 int mm_answer_pam_query(int, Buffer *); 166 int mm_answer_pam_respond(int, Buffer *); 167 int mm_answer_pam_free_ctx(int, Buffer *); 168 #endif 169 170 #ifdef GSSAPI 171 int mm_answer_gss_setup_ctx(int, Buffer *); 172 int mm_answer_gss_accept_ctx(int, Buffer *); 173 int mm_answer_gss_userok(int, Buffer *); 174 int mm_answer_gss_checkmic(int, Buffer *); 175 #endif 176 177 #ifdef SSH_AUDIT_EVENTS 178 int mm_answer_audit_event(int, Buffer *); 179 int mm_answer_audit_command(int, Buffer *); 180 #endif 181 182 static Authctxt *authctxt; 183 static BIGNUM *ssh1_challenge = NULL; /* used for ssh1 rsa auth */ 184 185 /* local state for key verify */ 186 static u_char *key_blob = NULL; 187 static u_int key_bloblen = 0; 188 static int key_blobtype = MM_NOKEY; 189 static char *hostbased_cuser = NULL; 190 static char *hostbased_chost = NULL; 191 static char *auth_method = "unknown"; 192 static u_int session_id2_len = 0; 193 static u_char *session_id2 = NULL; 194 static pid_t monitor_child_pid; 195 196 struct mon_table { 197 enum monitor_reqtype type; 198 int flags; 199 int (*f)(int, Buffer *); 200 }; 201 202 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 203 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 204 #define MON_ONCE 0x0010 /* Disable after calling */ 205 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 206 207 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 208 209 #define MON_PERMIT 0x1000 /* Request is permitted */ 210 211 struct mon_table mon_dispatch_proto20[] = { 212 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 213 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 214 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 215 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 216 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 217 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 218 #ifdef USE_PAM 219 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 220 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 221 {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx}, 222 {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query}, 223 {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond}, 224 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 225 #endif 226 #ifdef SSH_AUDIT_EVENTS 227 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 228 #endif 229 #ifdef BSD_AUTH 230 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 231 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 232 #endif 233 #ifdef SKEY 234 {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery}, 235 {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond}, 236 #endif 237 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 238 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 239 #ifdef GSSAPI 240 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 241 {MONITOR_REQ_GSSSTEP, MON_ISAUTH, mm_answer_gss_accept_ctx}, 242 {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok}, 243 {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, mm_answer_gss_checkmic}, 244 #endif 245 {0, 0, NULL} 246 }; 247 248 struct mon_table mon_dispatch_postauth20[] = { 249 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 250 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 251 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 252 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 253 {MONITOR_REQ_TERM, 0, mm_answer_term}, 254 #ifdef SSH_AUDIT_EVENTS 255 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 256 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command}, 257 #endif 258 {0, 0, NULL} 259 }; 260 261 struct mon_table mon_dispatch_proto15[] = { 262 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 263 {MONITOR_REQ_SESSKEY, MON_ONCE, mm_answer_sesskey}, 264 {MONITOR_REQ_SESSID, MON_ONCE, mm_answer_sessid}, 265 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 266 {MONITOR_REQ_RSAKEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_rsa_keyallowed}, 267 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_keyallowed}, 268 {MONITOR_REQ_RSACHALLENGE, MON_ONCE, mm_answer_rsa_challenge}, 269 {MONITOR_REQ_RSARESPONSE, MON_ONCE|MON_AUTHDECIDE, mm_answer_rsa_response}, 270 #ifdef BSD_AUTH 271 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 272 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 273 #endif 274 #ifdef SKEY 275 {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery}, 276 {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond}, 277 #endif 278 #ifdef USE_PAM 279 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 280 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 281 {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx}, 282 {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query}, 283 {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond}, 284 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 285 #endif 286 #ifdef SSH_AUDIT_EVENTS 287 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 288 #endif 289 {0, 0, NULL} 290 }; 291 292 struct mon_table mon_dispatch_postauth15[] = { 293 {MONITOR_REQ_PTY, MON_ONCE, mm_answer_pty}, 294 {MONITOR_REQ_PTYCLEANUP, MON_ONCE, mm_answer_pty_cleanup}, 295 {MONITOR_REQ_TERM, 0, mm_answer_term}, 296 #ifdef SSH_AUDIT_EVENTS 297 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 298 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT|MON_ONCE, mm_answer_audit_command}, 299 #endif 300 {0, 0, NULL} 301 }; 302 303 struct mon_table *mon_dispatch; 304 305 /* Specifies if a certain message is allowed at the moment */ 306 307 static void 308 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 309 { 310 while (ent->f != NULL) { 311 if (ent->type == type) { 312 ent->flags &= ~MON_PERMIT; 313 ent->flags |= permit ? MON_PERMIT : 0; 314 return; 315 } 316 ent++; 317 } 318 } 319 320 static void 321 monitor_permit_authentications(int permit) 322 { 323 struct mon_table *ent = mon_dispatch; 324 325 while (ent->f != NULL) { 326 if (ent->flags & MON_AUTH) { 327 ent->flags &= ~MON_PERMIT; 328 ent->flags |= permit ? MON_PERMIT : 0; 329 } 330 ent++; 331 } 332 } 333 334 void 335 monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor) 336 { 337 struct mon_table *ent; 338 int authenticated = 0; 339 340 debug3("preauth child monitor started"); 341 342 authctxt = _authctxt; 343 memset(authctxt, 0, sizeof(*authctxt)); 344 345 authctxt->loginmsg = &loginmsg; 346 347 if (compat20) { 348 mon_dispatch = mon_dispatch_proto20; 349 350 /* Permit requests for moduli and signatures */ 351 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 352 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 353 } else { 354 mon_dispatch = mon_dispatch_proto15; 355 356 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1); 357 } 358 359 /* The first few requests do not require asynchronous access */ 360 while (!authenticated) { 361 auth_method = "unknown"; 362 authenticated = (monitor_read(pmonitor, mon_dispatch, &ent) == 1); 363 if (authenticated) { 364 if (!(ent->flags & MON_AUTHDECIDE)) 365 fatal("%s: unexpected authentication from %d", 366 __func__, ent->type); 367 if (authctxt->pw->pw_uid == 0 && 368 !auth_root_allowed(auth_method)) 369 authenticated = 0; 370 #ifdef USE_PAM 371 /* PAM needs to perform account checks after auth */ 372 if (options.use_pam && authenticated) { 373 Buffer m; 374 375 buffer_init(&m); 376 mm_request_receive_expect(pmonitor->m_sendfd, 377 MONITOR_REQ_PAM_ACCOUNT, &m); 378 authenticated = mm_answer_pam_account(pmonitor->m_sendfd, &m); 379 buffer_free(&m); 380 } 381 #endif 382 } 383 384 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 385 auth_log(authctxt, authenticated, auth_method, 386 compat20 ? " ssh2" : ""); 387 if (!authenticated) 388 authctxt->failures++; 389 } 390 } 391 392 if (!authctxt->valid) 393 fatal("%s: authenticated invalid user", __func__); 394 if (strcmp(auth_method, "unknown") == 0) 395 fatal("%s: authentication method name unknown", __func__); 396 397 debug("%s: %s has been authenticated by privileged process", 398 __func__, authctxt->user); 399 400 mm_get_keystate(pmonitor); 401 } 402 403 static void 404 monitor_set_child_handler(pid_t pid) 405 { 406 monitor_child_pid = pid; 407 } 408 409 static void 410 monitor_child_handler(int sig) 411 { 412 kill(monitor_child_pid, sig); 413 } 414 415 void 416 monitor_child_postauth(struct monitor *pmonitor) 417 { 418 monitor_set_child_handler(pmonitor->m_pid); 419 signal(SIGHUP, &monitor_child_handler); 420 signal(SIGTERM, &monitor_child_handler); 421 422 if (compat20) { 423 mon_dispatch = mon_dispatch_postauth20; 424 425 /* Permit requests for moduli and signatures */ 426 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 427 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 428 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 429 } else { 430 mon_dispatch = mon_dispatch_postauth15; 431 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 432 } 433 if (!no_pty_flag) { 434 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 435 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 436 } 437 438 for (;;) 439 monitor_read(pmonitor, mon_dispatch, NULL); 440 } 441 442 void 443 monitor_sync(struct monitor *pmonitor) 444 { 445 if (options.compression) { 446 /* The member allocation is not visible, so sync it */ 447 mm_share_sync(&pmonitor->m_zlib, &pmonitor->m_zback); 448 } 449 } 450 451 int 452 monitor_read(struct monitor *pmonitor, struct mon_table *ent, 453 struct mon_table **pent) 454 { 455 Buffer m; 456 int ret; 457 u_char type; 458 459 buffer_init(&m); 460 461 mm_request_receive(pmonitor->m_sendfd, &m); 462 type = buffer_get_char(&m); 463 464 debug3("%s: checking request %d", __func__, type); 465 466 while (ent->f != NULL) { 467 if (ent->type == type) 468 break; 469 ent++; 470 } 471 472 if (ent->f != NULL) { 473 if (!(ent->flags & MON_PERMIT)) 474 fatal("%s: unpermitted request %d", __func__, 475 type); 476 ret = (*ent->f)(pmonitor->m_sendfd, &m); 477 buffer_free(&m); 478 479 /* The child may use this request only once, disable it */ 480 if (ent->flags & MON_ONCE) { 481 debug2("%s: %d used once, disabling now", __func__, 482 type); 483 ent->flags &= ~MON_PERMIT; 484 } 485 486 if (pent != NULL) 487 *pent = ent; 488 489 return ret; 490 } 491 492 fatal("%s: unsupported request: %d", __func__, type); 493 494 /* NOTREACHED */ 495 return (-1); 496 } 497 498 /* allowed key state */ 499 static int 500 monitor_allowed_key(u_char *blob, u_int bloblen) 501 { 502 /* make sure key is allowed */ 503 if (key_blob == NULL || key_bloblen != bloblen || 504 memcmp(key_blob, blob, key_bloblen)) 505 return (0); 506 return (1); 507 } 508 509 static void 510 monitor_reset_key_state(void) 511 { 512 /* reset state */ 513 if (key_blob != NULL) 514 xfree(key_blob); 515 if (hostbased_cuser != NULL) 516 xfree(hostbased_cuser); 517 if (hostbased_chost != NULL) 518 xfree(hostbased_chost); 519 key_blob = NULL; 520 key_bloblen = 0; 521 key_blobtype = MM_NOKEY; 522 hostbased_cuser = NULL; 523 hostbased_chost = NULL; 524 } 525 526 int 527 mm_answer_moduli(int sock, Buffer *m) 528 { 529 DH *dh; 530 int min, want, max; 531 532 min = buffer_get_int(m); 533 want = buffer_get_int(m); 534 max = buffer_get_int(m); 535 536 debug3("%s: got parameters: %d %d %d", 537 __func__, min, want, max); 538 /* We need to check here, too, in case the child got corrupted */ 539 if (max < min || want < min || max < want) 540 fatal("%s: bad parameters: %d %d %d", 541 __func__, min, want, max); 542 543 buffer_clear(m); 544 545 dh = choose_dh(min, want, max); 546 if (dh == NULL) { 547 buffer_put_char(m, 0); 548 return (0); 549 } else { 550 /* Send first bignum */ 551 buffer_put_char(m, 1); 552 buffer_put_bignum2(m, dh->p); 553 buffer_put_bignum2(m, dh->g); 554 555 DH_free(dh); 556 } 557 mm_request_send(sock, MONITOR_ANS_MODULI, m); 558 return (0); 559 } 560 561 int 562 mm_answer_sign(int sock, Buffer *m) 563 { 564 Key *key; 565 u_char *p; 566 u_char *signature; 567 u_int siglen, datlen; 568 int keyid; 569 570 debug3("%s", __func__); 571 572 keyid = buffer_get_int(m); 573 p = buffer_get_string(m, &datlen); 574 575 /* 576 * Supported KEX types will only return SHA1 (20 byte) or 577 * SHA256 (32 byte) hashes 578 */ 579 if (datlen != 20 && datlen != 32) 580 fatal("%s: data length incorrect: %u", __func__, datlen); 581 582 /* save session id, it will be passed on the first call */ 583 if (session_id2_len == 0) { 584 session_id2_len = datlen; 585 session_id2 = xmalloc(session_id2_len); 586 memcpy(session_id2, p, session_id2_len); 587 } 588 589 if ((key = get_hostkey_by_index(keyid)) == NULL) 590 fatal("%s: no hostkey from index %d", __func__, keyid); 591 if (key_sign(key, &signature, &siglen, p, datlen) < 0) 592 fatal("%s: key_sign failed", __func__); 593 594 debug3("%s: signature %p(%u)", __func__, signature, siglen); 595 596 buffer_clear(m); 597 buffer_put_string(m, signature, siglen); 598 599 xfree(p); 600 xfree(signature); 601 602 mm_request_send(sock, MONITOR_ANS_SIGN, m); 603 604 /* Turn on permissions for getpwnam */ 605 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 606 607 return (0); 608 } 609 610 /* Retrieves the password entry and also checks if the user is permitted */ 611 612 int 613 mm_answer_pwnamallow(int sock, Buffer *m) 614 { 615 char *username; 616 struct passwd *pwent; 617 int allowed = 0; 618 619 debug3("%s", __func__); 620 621 if (authctxt->attempt++ != 0) 622 fatal("%s: multiple attempts for getpwnam", __func__); 623 624 username = buffer_get_string(m, NULL); 625 626 pwent = getpwnamallow(username); 627 628 authctxt->user = xstrdup(username); 629 setproctitle("%s [priv]", pwent ? username : "unknown"); 630 xfree(username); 631 632 buffer_clear(m); 633 634 if (pwent == NULL) { 635 buffer_put_char(m, 0); 636 authctxt->pw = fakepw(); 637 goto out; 638 } 639 640 allowed = 1; 641 authctxt->pw = pwent; 642 authctxt->valid = 1; 643 644 buffer_put_char(m, 1); 645 buffer_put_string(m, pwent, sizeof(struct passwd)); 646 buffer_put_cstring(m, pwent->pw_name); 647 buffer_put_cstring(m, "*"); 648 buffer_put_cstring(m, pwent->pw_gecos); 649 #ifdef HAVE_PW_CLASS_IN_PASSWD 650 buffer_put_cstring(m, pwent->pw_class); 651 #endif 652 buffer_put_cstring(m, pwent->pw_dir); 653 buffer_put_cstring(m, pwent->pw_shell); 654 655 out: 656 debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed); 657 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 658 659 /* For SSHv1 allow authentication now */ 660 if (!compat20) 661 monitor_permit_authentications(1); 662 else { 663 /* Allow service/style information on the auth context */ 664 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 665 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 666 } 667 668 #ifdef USE_PAM 669 if (options.use_pam) 670 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); 671 #endif 672 673 return (0); 674 } 675 676 int mm_answer_auth2_read_banner(int sock, Buffer *m) 677 { 678 char *banner; 679 680 buffer_clear(m); 681 banner = auth2_read_banner(); 682 buffer_put_cstring(m, banner != NULL ? banner : ""); 683 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 684 685 if (banner != NULL) 686 xfree(banner); 687 688 return (0); 689 } 690 691 int 692 mm_answer_authserv(int sock, Buffer *m) 693 { 694 monitor_permit_authentications(1); 695 696 authctxt->service = buffer_get_string(m, NULL); 697 authctxt->style = buffer_get_string(m, NULL); 698 debug3("%s: service=%s, style=%s", 699 __func__, authctxt->service, authctxt->style); 700 701 if (strlen(authctxt->style) == 0) { 702 xfree(authctxt->style); 703 authctxt->style = NULL; 704 } 705 706 return (0); 707 } 708 709 int 710 mm_answer_authpassword(int sock, Buffer *m) 711 { 712 static int call_count; 713 char *passwd; 714 int authenticated; 715 u_int plen; 716 717 passwd = buffer_get_string(m, &plen); 718 /* Only authenticate if the context is valid */ 719 authenticated = options.password_authentication && 720 auth_password(authctxt, passwd); 721 memset(passwd, 0, strlen(passwd)); 722 xfree(passwd); 723 724 buffer_clear(m); 725 buffer_put_int(m, authenticated); 726 727 debug3("%s: sending result %d", __func__, authenticated); 728 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 729 730 call_count++; 731 if (plen == 0 && call_count == 1) 732 auth_method = "none"; 733 else 734 auth_method = "password"; 735 736 /* Causes monitor loop to terminate if authenticated */ 737 return (authenticated); 738 } 739 740 #ifdef BSD_AUTH 741 int 742 mm_answer_bsdauthquery(int sock, Buffer *m) 743 { 744 char *name, *infotxt; 745 u_int numprompts; 746 u_int *echo_on; 747 char **prompts; 748 u_int success; 749 750 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 751 &prompts, &echo_on) < 0 ? 0 : 1; 752 753 buffer_clear(m); 754 buffer_put_int(m, success); 755 if (success) 756 buffer_put_cstring(m, prompts[0]); 757 758 debug3("%s: sending challenge success: %u", __func__, success); 759 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 760 761 if (success) { 762 xfree(name); 763 xfree(infotxt); 764 xfree(prompts); 765 xfree(echo_on); 766 } 767 768 return (0); 769 } 770 771 int 772 mm_answer_bsdauthrespond(int sock, Buffer *m) 773 { 774 char *response; 775 int authok; 776 777 if (authctxt->as == 0) 778 fatal("%s: no bsd auth session", __func__); 779 780 response = buffer_get_string(m, NULL); 781 authok = options.challenge_response_authentication && 782 auth_userresponse(authctxt->as, response, 0); 783 authctxt->as = NULL; 784 debug3("%s: <%s> = <%d>", __func__, response, authok); 785 xfree(response); 786 787 buffer_clear(m); 788 buffer_put_int(m, authok); 789 790 debug3("%s: sending authenticated: %d", __func__, authok); 791 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 792 793 auth_method = "bsdauth"; 794 795 return (authok != 0); 796 } 797 #endif 798 799 #ifdef SKEY 800 int 801 mm_answer_skeyquery(int sock, Buffer *m) 802 { 803 struct skey skey; 804 char challenge[1024]; 805 u_int success; 806 807 success = _compat_skeychallenge(&skey, authctxt->user, challenge, 808 sizeof(challenge)) < 0 ? 0 : 1; 809 810 buffer_clear(m); 811 buffer_put_int(m, success); 812 if (success) 813 buffer_put_cstring(m, challenge); 814 815 debug3("%s: sending challenge success: %u", __func__, success); 816 mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m); 817 818 return (0); 819 } 820 821 int 822 mm_answer_skeyrespond(int sock, Buffer *m) 823 { 824 char *response; 825 int authok; 826 827 response = buffer_get_string(m, NULL); 828 829 authok = (options.challenge_response_authentication && 830 authctxt->valid && 831 skey_haskey(authctxt->pw->pw_name) == 0 && 832 skey_passcheck(authctxt->pw->pw_name, response) != -1); 833 834 xfree(response); 835 836 buffer_clear(m); 837 buffer_put_int(m, authok); 838 839 debug3("%s: sending authenticated: %d", __func__, authok); 840 mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m); 841 842 auth_method = "skey"; 843 844 return (authok != 0); 845 } 846 #endif 847 848 #ifdef USE_PAM 849 int 850 mm_answer_pam_start(int sock, Buffer *m) 851 { 852 if (!options.use_pam) 853 fatal("UsePAM not set, but ended up in %s anyway", __func__); 854 855 start_pam(authctxt); 856 857 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); 858 859 return (0); 860 } 861 862 int 863 mm_answer_pam_account(int sock, Buffer *m) 864 { 865 u_int ret; 866 867 if (!options.use_pam) 868 fatal("UsePAM not set, but ended up in %s anyway", __func__); 869 870 ret = do_pam_account(); 871 872 buffer_put_int(m, ret); 873 buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg)); 874 875 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m); 876 877 return (ret); 878 } 879 880 static void *sshpam_ctxt, *sshpam_authok; 881 extern KbdintDevice sshpam_device; 882 883 int 884 mm_answer_pam_init_ctx(int sock, Buffer *m) 885 { 886 887 debug3("%s", __func__); 888 authctxt->user = buffer_get_string(m, NULL); 889 sshpam_ctxt = (sshpam_device.init_ctx)(authctxt); 890 sshpam_authok = NULL; 891 buffer_clear(m); 892 if (sshpam_ctxt != NULL) { 893 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 894 buffer_put_int(m, 1); 895 } else { 896 buffer_put_int(m, 0); 897 } 898 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); 899 return (0); 900 } 901 902 int 903 mm_answer_pam_query(int sock, Buffer *m) 904 { 905 char *name, *info, **prompts; 906 u_int i, num, *echo_on; 907 int ret; 908 909 debug3("%s", __func__); 910 sshpam_authok = NULL; 911 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, &num, &prompts, &echo_on); 912 if (ret == 0 && num == 0) 913 sshpam_authok = sshpam_ctxt; 914 if (num > 1 || name == NULL || info == NULL) 915 ret = -1; 916 buffer_clear(m); 917 buffer_put_int(m, ret); 918 buffer_put_cstring(m, name); 919 xfree(name); 920 buffer_put_cstring(m, info); 921 xfree(info); 922 buffer_put_int(m, num); 923 for (i = 0; i < num; ++i) { 924 buffer_put_cstring(m, prompts[i]); 925 xfree(prompts[i]); 926 buffer_put_int(m, echo_on[i]); 927 } 928 if (prompts != NULL) 929 xfree(prompts); 930 if (echo_on != NULL) 931 xfree(echo_on); 932 auth_method = "keyboard-interactive/pam"; 933 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m); 934 return (0); 935 } 936 937 int 938 mm_answer_pam_respond(int sock, Buffer *m) 939 { 940 char **resp; 941 u_int i, num; 942 int ret; 943 944 debug3("%s", __func__); 945 sshpam_authok = NULL; 946 num = buffer_get_int(m); 947 if (num > 0) { 948 resp = xcalloc(num, sizeof(char *)); 949 for (i = 0; i < num; ++i) 950 resp[i] = buffer_get_string(m, NULL); 951 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp); 952 for (i = 0; i < num; ++i) 953 xfree(resp[i]); 954 xfree(resp); 955 } else { 956 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL); 957 } 958 buffer_clear(m); 959 buffer_put_int(m, ret); 960 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m); 961 auth_method = "keyboard-interactive/pam"; 962 if (ret == 0) 963 sshpam_authok = sshpam_ctxt; 964 return (0); 965 } 966 967 int 968 mm_answer_pam_free_ctx(int sock, Buffer *m) 969 { 970 971 debug3("%s", __func__); 972 (sshpam_device.free_ctx)(sshpam_ctxt); 973 buffer_clear(m); 974 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); 975 auth_method = "keyboard-interactive/pam"; 976 return (sshpam_authok == sshpam_ctxt); 977 } 978 #endif 979 980 static void 981 mm_append_debug(Buffer *m) 982 { 983 if (auth_debug_init && buffer_len(&auth_debug)) { 984 debug3("%s: Appending debug messages for child", __func__); 985 buffer_append(m, buffer_ptr(&auth_debug), 986 buffer_len(&auth_debug)); 987 buffer_clear(&auth_debug); 988 } 989 } 990 991 int 992 mm_answer_keyallowed(int sock, Buffer *m) 993 { 994 Key *key; 995 char *cuser, *chost; 996 u_char *blob; 997 u_int bloblen; 998 enum mm_keytype type = 0; 999 int allowed = 0; 1000 1001 debug3("%s entering", __func__); 1002 1003 type = buffer_get_int(m); 1004 cuser = buffer_get_string(m, NULL); 1005 chost = buffer_get_string(m, NULL); 1006 blob = buffer_get_string(m, &bloblen); 1007 1008 key = key_from_blob(blob, bloblen); 1009 1010 if ((compat20 && type == MM_RSAHOSTKEY) || 1011 (!compat20 && type != MM_RSAHOSTKEY)) 1012 fatal("%s: key type and protocol mismatch", __func__); 1013 1014 debug3("%s: key_from_blob: %p", __func__, key); 1015 1016 if (key != NULL && authctxt->valid) { 1017 switch (type) { 1018 case MM_USERKEY: 1019 allowed = options.pubkey_authentication && 1020 user_key_allowed(authctxt->pw, key); 1021 auth_method = "publickey"; 1022 break; 1023 case MM_HOSTKEY: 1024 allowed = options.hostbased_authentication && 1025 hostbased_key_allowed(authctxt->pw, 1026 cuser, chost, key); 1027 auth_method = "hostbased"; 1028 break; 1029 case MM_RSAHOSTKEY: 1030 key->type = KEY_RSA1; /* XXX */ 1031 allowed = options.rhosts_rsa_authentication && 1032 auth_rhosts_rsa_key_allowed(authctxt->pw, 1033 cuser, chost, key); 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" : "disallowed"); 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 s->used = 0; 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 mm_send_fd(sock, s->ptyfd); 1323 mm_send_fd(sock, s->ttyfd); 1324 1325 /* make sure nothing uses fd 0 */ 1326 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0) 1327 fatal("%s: open(/dev/null): %s", __func__, strerror(errno)); 1328 if (fd0 != 0) 1329 error("%s: fd0 %d != 0", __func__, fd0); 1330 1331 /* slave is not needed */ 1332 close(s->ttyfd); 1333 s->ttyfd = s->ptyfd; 1334 /* no need to dup() because nobody closes ptyfd */ 1335 s->ptymaster = s->ptyfd; 1336 1337 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd); 1338 1339 return (0); 1340 1341 error: 1342 if (s != NULL) 1343 mm_session_close(s); 1344 buffer_put_int(m, 0); 1345 mm_request_send(sock, MONITOR_ANS_PTY, m); 1346 return (0); 1347 } 1348 1349 int 1350 mm_answer_pty_cleanup(int sock, Buffer *m) 1351 { 1352 Session *s; 1353 char *tty; 1354 1355 debug3("%s entering", __func__); 1356 1357 tty = buffer_get_string(m, NULL); 1358 if ((s = session_by_tty(tty)) != NULL) 1359 mm_session_close(s); 1360 buffer_clear(m); 1361 xfree(tty); 1362 return (0); 1363 } 1364 1365 int 1366 mm_answer_sesskey(int sock, Buffer *m) 1367 { 1368 BIGNUM *p; 1369 int rsafail; 1370 1371 /* Turn off permissions */ 1372 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 0); 1373 1374 if ((p = BN_new()) == NULL) 1375 fatal("%s: BN_new", __func__); 1376 1377 buffer_get_bignum2(m, p); 1378 1379 rsafail = ssh1_session_key(p); 1380 1381 buffer_clear(m); 1382 buffer_put_int(m, rsafail); 1383 buffer_put_bignum2(m, p); 1384 1385 BN_clear_free(p); 1386 1387 mm_request_send(sock, MONITOR_ANS_SESSKEY, m); 1388 1389 /* Turn on permissions for sessid passing */ 1390 monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1); 1391 1392 return (0); 1393 } 1394 1395 int 1396 mm_answer_sessid(int sock, Buffer *m) 1397 { 1398 int i; 1399 1400 debug3("%s entering", __func__); 1401 1402 if (buffer_len(m) != 16) 1403 fatal("%s: bad ssh1 session id", __func__); 1404 for (i = 0; i < 16; i++) 1405 session_id[i] = buffer_get_char(m); 1406 1407 /* Turn on permissions for getpwnam */ 1408 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 1409 1410 return (0); 1411 } 1412 1413 int 1414 mm_answer_rsa_keyallowed(int sock, Buffer *m) 1415 { 1416 BIGNUM *client_n; 1417 Key *key = NULL; 1418 u_char *blob = NULL; 1419 u_int blen = 0; 1420 int allowed = 0; 1421 1422 debug3("%s entering", __func__); 1423 1424 auth_method = "rsa"; 1425 if (options.rsa_authentication && authctxt->valid) { 1426 if ((client_n = BN_new()) == NULL) 1427 fatal("%s: BN_new", __func__); 1428 buffer_get_bignum2(m, client_n); 1429 allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key); 1430 BN_clear_free(client_n); 1431 } 1432 buffer_clear(m); 1433 buffer_put_int(m, allowed); 1434 buffer_put_int(m, forced_command != NULL); 1435 1436 /* clear temporarily storage (used by generate challenge) */ 1437 monitor_reset_key_state(); 1438 1439 if (allowed && key != NULL) { 1440 key->type = KEY_RSA; /* cheat for key_to_blob */ 1441 if (key_to_blob(key, &blob, &blen) == 0) 1442 fatal("%s: key_to_blob failed", __func__); 1443 buffer_put_string(m, blob, blen); 1444 1445 /* Save temporarily for comparison in verify */ 1446 key_blob = blob; 1447 key_bloblen = blen; 1448 key_blobtype = MM_RSAUSERKEY; 1449 } 1450 if (key != NULL) 1451 key_free(key); 1452 1453 mm_append_debug(m); 1454 1455 mm_request_send(sock, MONITOR_ANS_RSAKEYALLOWED, m); 1456 1457 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed); 1458 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0); 1459 return (0); 1460 } 1461 1462 int 1463 mm_answer_rsa_challenge(int sock, Buffer *m) 1464 { 1465 Key *key = NULL; 1466 u_char *blob; 1467 u_int blen; 1468 1469 debug3("%s entering", __func__); 1470 1471 if (!authctxt->valid) 1472 fatal("%s: authctxt not valid", __func__); 1473 blob = buffer_get_string(m, &blen); 1474 if (!monitor_allowed_key(blob, blen)) 1475 fatal("%s: bad key, not previously allowed", __func__); 1476 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) 1477 fatal("%s: key type mismatch", __func__); 1478 if ((key = key_from_blob(blob, blen)) == NULL) 1479 fatal("%s: received bad key", __func__); 1480 1481 if (ssh1_challenge) 1482 BN_clear_free(ssh1_challenge); 1483 ssh1_challenge = auth_rsa_generate_challenge(key); 1484 1485 buffer_clear(m); 1486 buffer_put_bignum2(m, ssh1_challenge); 1487 1488 debug3("%s sending reply", __func__); 1489 mm_request_send(sock, MONITOR_ANS_RSACHALLENGE, m); 1490 1491 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1); 1492 1493 xfree(blob); 1494 key_free(key); 1495 return (0); 1496 } 1497 1498 int 1499 mm_answer_rsa_response(int sock, Buffer *m) 1500 { 1501 Key *key = NULL; 1502 u_char *blob, *response; 1503 u_int blen, len; 1504 int success; 1505 1506 debug3("%s entering", __func__); 1507 1508 if (!authctxt->valid) 1509 fatal("%s: authctxt not valid", __func__); 1510 if (ssh1_challenge == NULL) 1511 fatal("%s: no ssh1_challenge", __func__); 1512 1513 blob = buffer_get_string(m, &blen); 1514 if (!monitor_allowed_key(blob, blen)) 1515 fatal("%s: bad key, not previously allowed", __func__); 1516 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) 1517 fatal("%s: key type mismatch: %d", __func__, key_blobtype); 1518 if ((key = key_from_blob(blob, blen)) == NULL) 1519 fatal("%s: received bad key", __func__); 1520 response = buffer_get_string(m, &len); 1521 if (len != 16) 1522 fatal("%s: received bad response to challenge", __func__); 1523 success = auth_rsa_verify_response(key, ssh1_challenge, response); 1524 1525 xfree(blob); 1526 key_free(key); 1527 xfree(response); 1528 1529 auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa"; 1530 1531 /* reset state */ 1532 BN_clear_free(ssh1_challenge); 1533 ssh1_challenge = NULL; 1534 monitor_reset_key_state(); 1535 1536 buffer_clear(m); 1537 buffer_put_int(m, success); 1538 mm_request_send(sock, MONITOR_ANS_RSARESPONSE, m); 1539 1540 return (success); 1541 } 1542 1543 int 1544 mm_answer_term(int sock, Buffer *req) 1545 { 1546 extern struct monitor *pmonitor; 1547 int res, status; 1548 1549 debug3("%s: tearing down sessions", __func__); 1550 1551 /* The child is terminating */ 1552 session_destroy_all(&mm_session_close); 1553 1554 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1555 if (errno != EINTR) 1556 exit(1); 1557 1558 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1559 1560 /* Terminate process */ 1561 exit(res); 1562 } 1563 1564 #ifdef SSH_AUDIT_EVENTS 1565 /* Report that an audit event occurred */ 1566 int 1567 mm_answer_audit_event(int socket, Buffer *m) 1568 { 1569 ssh_audit_event_t event; 1570 1571 debug3("%s entering", __func__); 1572 1573 event = buffer_get_int(m); 1574 switch(event) { 1575 case SSH_AUTH_FAIL_PUBKEY: 1576 case SSH_AUTH_FAIL_HOSTBASED: 1577 case SSH_AUTH_FAIL_GSSAPI: 1578 case SSH_LOGIN_EXCEED_MAXTRIES: 1579 case SSH_LOGIN_ROOT_DENIED: 1580 case SSH_CONNECTION_CLOSE: 1581 case SSH_INVALID_USER: 1582 audit_event(event); 1583 break; 1584 default: 1585 fatal("Audit event type %d not permitted", event); 1586 } 1587 1588 return (0); 1589 } 1590 1591 int 1592 mm_answer_audit_command(int socket, Buffer *m) 1593 { 1594 u_int len; 1595 char *cmd; 1596 1597 debug3("%s entering", __func__); 1598 cmd = buffer_get_string(m, &len); 1599 /* sanity check command, if so how? */ 1600 audit_run_command(cmd); 1601 xfree(cmd); 1602 return (0); 1603 } 1604 #endif /* SSH_AUDIT_EVENTS */ 1605 1606 void 1607 monitor_apply_keystate(struct monitor *pmonitor) 1608 { 1609 if (compat20) { 1610 set_newkeys(MODE_IN); 1611 set_newkeys(MODE_OUT); 1612 } else { 1613 packet_set_protocol_flags(child_state.ssh1protoflags); 1614 packet_set_encryption_key(child_state.ssh1key, 1615 child_state.ssh1keylen, child_state.ssh1cipher); 1616 xfree(child_state.ssh1key); 1617 } 1618 1619 /* for rc4 and other stateful ciphers */ 1620 packet_set_keycontext(MODE_OUT, child_state.keyout); 1621 xfree(child_state.keyout); 1622 packet_set_keycontext(MODE_IN, child_state.keyin); 1623 xfree(child_state.keyin); 1624 1625 if (!compat20) { 1626 packet_set_iv(MODE_OUT, child_state.ivout); 1627 xfree(child_state.ivout); 1628 packet_set_iv(MODE_IN, child_state.ivin); 1629 xfree(child_state.ivin); 1630 } 1631 1632 memcpy(&incoming_stream, &child_state.incoming, 1633 sizeof(incoming_stream)); 1634 memcpy(&outgoing_stream, &child_state.outgoing, 1635 sizeof(outgoing_stream)); 1636 1637 /* Update with new address */ 1638 if (options.compression) 1639 mm_init_compression(pmonitor->m_zlib); 1640 1641 /* Network I/O buffers */ 1642 /* XXX inefficient for large buffers, need: buffer_init_from_string */ 1643 buffer_clear(&input); 1644 buffer_append(&input, child_state.input, child_state.ilen); 1645 memset(child_state.input, 0, child_state.ilen); 1646 xfree(child_state.input); 1647 1648 buffer_clear(&output); 1649 buffer_append(&output, child_state.output, child_state.olen); 1650 memset(child_state.output, 0, child_state.olen); 1651 xfree(child_state.output); 1652 } 1653 1654 static Kex * 1655 mm_get_kex(Buffer *m) 1656 { 1657 Kex *kex; 1658 void *blob; 1659 u_int bloblen; 1660 1661 kex = xcalloc(1, sizeof(*kex)); 1662 kex->session_id = buffer_get_string(m, &kex->session_id_len); 1663 if ((session_id2 == NULL) || 1664 (kex->session_id_len != session_id2_len) || 1665 (memcmp(kex->session_id, session_id2, session_id2_len) != 0)) 1666 fatal("mm_get_get: internal error: bad session id"); 1667 kex->we_need = buffer_get_int(m); 1668 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; 1669 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; 1670 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1671 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1672 kex->server = 1; 1673 kex->hostkey_type = buffer_get_int(m); 1674 kex->kex_type = buffer_get_int(m); 1675 blob = buffer_get_string(m, &bloblen); 1676 buffer_init(&kex->my); 1677 buffer_append(&kex->my, blob, bloblen); 1678 xfree(blob); 1679 blob = buffer_get_string(m, &bloblen); 1680 buffer_init(&kex->peer); 1681 buffer_append(&kex->peer, blob, bloblen); 1682 xfree(blob); 1683 kex->done = 1; 1684 kex->flags = buffer_get_int(m); 1685 kex->client_version_string = buffer_get_string(m, NULL); 1686 kex->server_version_string = buffer_get_string(m, NULL); 1687 kex->load_host_key=&get_hostkey_by_type; 1688 kex->host_key_index=&get_hostkey_index; 1689 1690 return (kex); 1691 } 1692 1693 /* This function requries careful sanity checking */ 1694 1695 void 1696 mm_get_keystate(struct monitor *pmonitor) 1697 { 1698 Buffer m; 1699 u_char *blob, *p; 1700 u_int bloblen, plen; 1701 u_int32_t seqnr, packets; 1702 u_int64_t blocks; 1703 1704 debug3("%s: Waiting for new keys", __func__); 1705 1706 buffer_init(&m); 1707 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, &m); 1708 if (!compat20) { 1709 child_state.ssh1protoflags = buffer_get_int(&m); 1710 child_state.ssh1cipher = buffer_get_int(&m); 1711 child_state.ssh1key = buffer_get_string(&m, 1712 &child_state.ssh1keylen); 1713 child_state.ivout = buffer_get_string(&m, 1714 &child_state.ivoutlen); 1715 child_state.ivin = buffer_get_string(&m, &child_state.ivinlen); 1716 goto skip; 1717 } else { 1718 /* Get the Kex for rekeying */ 1719 *pmonitor->m_pkex = mm_get_kex(&m); 1720 } 1721 1722 blob = buffer_get_string(&m, &bloblen); 1723 current_keys[MODE_OUT] = mm_newkeys_from_blob(blob, bloblen); 1724 xfree(blob); 1725 1726 debug3("%s: Waiting for second key", __func__); 1727 blob = buffer_get_string(&m, &bloblen); 1728 current_keys[MODE_IN] = mm_newkeys_from_blob(blob, bloblen); 1729 xfree(blob); 1730 1731 /* Now get sequence numbers for the packets */ 1732 seqnr = buffer_get_int(&m); 1733 blocks = buffer_get_int64(&m); 1734 packets = buffer_get_int(&m); 1735 packet_set_state(MODE_OUT, seqnr, blocks, packets); 1736 seqnr = buffer_get_int(&m); 1737 blocks = buffer_get_int64(&m); 1738 packets = buffer_get_int(&m); 1739 packet_set_state(MODE_IN, seqnr, blocks, packets); 1740 1741 skip: 1742 /* Get the key context */ 1743 child_state.keyout = buffer_get_string(&m, &child_state.keyoutlen); 1744 child_state.keyin = buffer_get_string(&m, &child_state.keyinlen); 1745 1746 debug3("%s: Getting compression state", __func__); 1747 /* Get compression state */ 1748 p = buffer_get_string(&m, &plen); 1749 if (plen != sizeof(child_state.outgoing)) 1750 fatal("%s: bad request size", __func__); 1751 memcpy(&child_state.outgoing, p, sizeof(child_state.outgoing)); 1752 xfree(p); 1753 1754 p = buffer_get_string(&m, &plen); 1755 if (plen != sizeof(child_state.incoming)) 1756 fatal("%s: bad request size", __func__); 1757 memcpy(&child_state.incoming, p, sizeof(child_state.incoming)); 1758 xfree(p); 1759 1760 /* Network I/O buffers */ 1761 debug3("%s: Getting Network I/O buffers", __func__); 1762 child_state.input = buffer_get_string(&m, &child_state.ilen); 1763 child_state.output = buffer_get_string(&m, &child_state.olen); 1764 1765 buffer_free(&m); 1766 } 1767 1768 1769 /* Allocation functions for zlib */ 1770 void * 1771 mm_zalloc(struct mm_master *mm, u_int ncount, u_int size) 1772 { 1773 size_t len = (size_t) size * ncount; 1774 void *address; 1775 1776 if (len == 0 || ncount > SIZE_T_MAX / size) 1777 fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size); 1778 1779 address = mm_malloc(mm, len); 1780 1781 return (address); 1782 } 1783 1784 void 1785 mm_zfree(struct mm_master *mm, void *address) 1786 { 1787 mm_free(mm, address); 1788 } 1789 1790 void 1791 mm_init_compression(struct mm_master *mm) 1792 { 1793 outgoing_stream.zalloc = (alloc_func)mm_zalloc; 1794 outgoing_stream.zfree = (free_func)mm_zfree; 1795 outgoing_stream.opaque = mm; 1796 1797 incoming_stream.zalloc = (alloc_func)mm_zalloc; 1798 incoming_stream.zfree = (free_func)mm_zfree; 1799 incoming_stream.opaque = mm; 1800 } 1801 1802 /* XXX */ 1803 1804 #define FD_CLOSEONEXEC(x) do { \ 1805 if (fcntl(x, F_SETFD, 1) == -1) \ 1806 fatal("fcntl(%d, F_SETFD)", x); \ 1807 } while (0) 1808 1809 static void 1810 monitor_socketpair(int *pair) 1811 { 1812 #ifdef HAVE_SOCKETPAIR 1813 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1814 fatal("%s: socketpair", __func__); 1815 #else 1816 fatal("%s: UsePrivilegeSeparation=yes not supported", 1817 __func__); 1818 #endif 1819 FD_CLOSEONEXEC(pair[0]); 1820 FD_CLOSEONEXEC(pair[1]); 1821 } 1822 1823 #define MM_MEMSIZE 65536 1824 1825 struct monitor * 1826 monitor_init(void) 1827 { 1828 struct monitor *mon; 1829 int pair[2]; 1830 1831 mon = xcalloc(1, sizeof(*mon)); 1832 1833 monitor_socketpair(pair); 1834 1835 mon->m_recvfd = pair[0]; 1836 mon->m_sendfd = pair[1]; 1837 1838 /* Used to share zlib space across processes */ 1839 if (options.compression) { 1840 mon->m_zback = mm_create(NULL, MM_MEMSIZE); 1841 mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE); 1842 1843 /* Compression needs to share state across borders */ 1844 mm_init_compression(mon->m_zlib); 1845 } 1846 1847 return mon; 1848 } 1849 1850 void 1851 monitor_reinit(struct monitor *mon) 1852 { 1853 int pair[2]; 1854 1855 monitor_socketpair(pair); 1856 1857 mon->m_recvfd = pair[0]; 1858 mon->m_sendfd = pair[1]; 1859 } 1860 1861 #ifdef GSSAPI 1862 int 1863 mm_answer_gss_setup_ctx(int sock, Buffer *m) 1864 { 1865 gss_OID_desc goid; 1866 OM_uint32 major; 1867 u_int len; 1868 1869 goid.elements = buffer_get_string(m, &len); 1870 goid.length = len; 1871 1872 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1873 1874 xfree(goid.elements); 1875 1876 buffer_clear(m); 1877 buffer_put_int(m, major); 1878 1879 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1880 1881 /* Now we have a context, enable the step */ 1882 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1883 1884 return (0); 1885 } 1886 1887 int 1888 mm_answer_gss_accept_ctx(int sock, Buffer *m) 1889 { 1890 gss_buffer_desc in; 1891 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1892 OM_uint32 major, minor; 1893 OM_uint32 flags = 0; /* GSI needs this */ 1894 u_int len; 1895 1896 in.value = buffer_get_string(m, &len); 1897 in.length = len; 1898 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1899 xfree(in.value); 1900 1901 buffer_clear(m); 1902 buffer_put_int(m, major); 1903 buffer_put_string(m, out.value, out.length); 1904 buffer_put_int(m, flags); 1905 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1906 1907 gss_release_buffer(&minor, &out); 1908 1909 if (major == GSS_S_COMPLETE) { 1910 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1911 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1912 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1913 } 1914 return (0); 1915 } 1916 1917 int 1918 mm_answer_gss_checkmic(int sock, Buffer *m) 1919 { 1920 gss_buffer_desc gssbuf, mic; 1921 OM_uint32 ret; 1922 u_int len; 1923 1924 gssbuf.value = buffer_get_string(m, &len); 1925 gssbuf.length = len; 1926 mic.value = buffer_get_string(m, &len); 1927 mic.length = len; 1928 1929 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1930 1931 xfree(gssbuf.value); 1932 xfree(mic.value); 1933 1934 buffer_clear(m); 1935 buffer_put_int(m, ret); 1936 1937 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1938 1939 if (!GSS_ERROR(ret)) 1940 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1941 1942 return (0); 1943 } 1944 1945 int 1946 mm_answer_gss_userok(int sock, Buffer *m) 1947 { 1948 int authenticated; 1949 1950 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1951 1952 buffer_clear(m); 1953 buffer_put_int(m, authenticated); 1954 1955 debug3("%s: sending result %d", __func__, authenticated); 1956 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1957 1958 auth_method = "gssapi-with-mic"; 1959 1960 /* Monitor loop will terminate if authenticated */ 1961 return (authenticated); 1962 } 1963 #endif /* GSSAPI */ 1964