1 /* $OpenBSD: monitor.c,v 1.166 2016/09/28 16:33:06 djm 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/socket.h> 32 #include "openbsd-compat/sys-tree.h" 33 #include <sys/wait.h> 34 35 #include <errno.h> 36 #include <fcntl.h> 37 #include <limits.h> 38 #ifdef HAVE_PATHS_H 39 #include <paths.h> 40 #endif 41 #include <pwd.h> 42 #include <signal.h> 43 #ifdef HAVE_STDINT_H 44 #include <stdint.h> 45 #endif 46 #include <stdlib.h> 47 #include <string.h> 48 #include <stdarg.h> 49 #include <stdio.h> 50 #include <unistd.h> 51 #ifdef HAVE_POLL_H 52 #include <poll.h> 53 #else 54 # ifdef HAVE_SYS_POLL_H 55 # include <sys/poll.h> 56 # endif 57 #endif 58 59 #ifdef SKEY 60 #include <skey.h> 61 #endif 62 63 #ifdef WITH_OPENSSL 64 #include <openssl/dh.h> 65 #endif 66 67 #include "openbsd-compat/sys-queue.h" 68 #include "atomicio.h" 69 #include "xmalloc.h" 70 #include "ssh.h" 71 #include "key.h" 72 #include "buffer.h" 73 #include "hostfile.h" 74 #include "auth.h" 75 #include "cipher.h" 76 #include "kex.h" 77 #include "dh.h" 78 #include "auth-pam.h" 79 #ifdef TARGET_OS_MAC /* XXX Broken krb5 headers on Mac */ 80 #undef TARGET_OS_MAC 81 #include "zlib.h" 82 #define TARGET_OS_MAC 1 83 #else 84 #include "zlib.h" 85 #endif 86 #include "packet.h" 87 #include "auth-options.h" 88 #include "sshpty.h" 89 #include "channels.h" 90 #include "session.h" 91 #include "sshlogin.h" 92 #include "canohost.h" 93 #include "log.h" 94 #include "misc.h" 95 #include "servconf.h" 96 #include "monitor.h" 97 #ifdef GSSAPI 98 #include "ssh-gss.h" 99 #endif 100 #include "monitor_wrap.h" 101 #include "monitor_fdpass.h" 102 #include "compat.h" 103 #include "ssh2.h" 104 #include "authfd.h" 105 #include "match.h" 106 #include "ssherr.h" 107 108 #ifdef GSSAPI 109 static Gssctxt *gsscontext = NULL; 110 #endif 111 112 /* Imports */ 113 extern ServerOptions options; 114 extern u_int utmp_len; 115 extern u_char session_id[]; 116 extern Buffer auth_debug; 117 extern int auth_debug_init; 118 extern Buffer loginmsg; 119 120 /* State exported from the child */ 121 static struct sshbuf *child_state; 122 123 /* Functions on the monitor that answer unprivileged requests */ 124 125 int mm_answer_moduli(int, Buffer *); 126 int mm_answer_sign(int, Buffer *); 127 int mm_answer_pwnamallow(int, Buffer *); 128 int mm_answer_auth2_read_banner(int, Buffer *); 129 int mm_answer_authserv(int, Buffer *); 130 int mm_answer_authpassword(int, Buffer *); 131 int mm_answer_bsdauthquery(int, Buffer *); 132 int mm_answer_bsdauthrespond(int, Buffer *); 133 int mm_answer_skeyquery(int, Buffer *); 134 int mm_answer_skeyrespond(int, Buffer *); 135 int mm_answer_keyallowed(int, Buffer *); 136 int mm_answer_keyverify(int, Buffer *); 137 int mm_answer_pty(int, Buffer *); 138 int mm_answer_pty_cleanup(int, Buffer *); 139 int mm_answer_term(int, Buffer *); 140 int mm_answer_rsa_keyallowed(int, Buffer *); 141 int mm_answer_rsa_challenge(int, Buffer *); 142 int mm_answer_rsa_response(int, Buffer *); 143 int mm_answer_sesskey(int, Buffer *); 144 int mm_answer_sessid(int, Buffer *); 145 146 #ifdef USE_PAM 147 int mm_answer_pam_start(int, Buffer *); 148 int mm_answer_pam_account(int, Buffer *); 149 int mm_answer_pam_init_ctx(int, Buffer *); 150 int mm_answer_pam_query(int, Buffer *); 151 int mm_answer_pam_respond(int, Buffer *); 152 int mm_answer_pam_free_ctx(int, Buffer *); 153 #endif 154 155 #ifdef GSSAPI 156 int mm_answer_gss_setup_ctx(int, Buffer *); 157 int mm_answer_gss_accept_ctx(int, Buffer *); 158 int mm_answer_gss_userok(int, Buffer *); 159 int mm_answer_gss_checkmic(int, Buffer *); 160 #endif 161 162 #ifdef SSH_AUDIT_EVENTS 163 int mm_answer_audit_event(int, Buffer *); 164 int mm_answer_audit_command(int, Buffer *); 165 #endif 166 167 static int monitor_read_log(struct monitor *); 168 169 static Authctxt *authctxt; 170 171 /* local state for key verify */ 172 static u_char *key_blob = NULL; 173 static u_int key_bloblen = 0; 174 static int key_blobtype = MM_NOKEY; 175 static char *hostbased_cuser = NULL; 176 static char *hostbased_chost = NULL; 177 static char *auth_method = "unknown"; 178 static char *auth_submethod = NULL; 179 static u_int session_id2_len = 0; 180 static u_char *session_id2 = NULL; 181 static pid_t monitor_child_pid; 182 183 struct mon_table { 184 enum monitor_reqtype type; 185 int flags; 186 int (*f)(int, Buffer *); 187 }; 188 189 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 190 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 191 #define MON_ONCE 0x0010 /* Disable after calling */ 192 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 193 194 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 195 196 #define MON_PERMIT 0x1000 /* Request is permitted */ 197 198 struct mon_table mon_dispatch_proto20[] = { 199 #ifdef WITH_OPENSSL 200 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 201 #endif 202 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 203 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 204 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 205 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 206 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 207 #ifdef USE_PAM 208 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 209 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 210 {MONITOR_REQ_PAM_INIT_CTX, MON_ONCE, mm_answer_pam_init_ctx}, 211 {MONITOR_REQ_PAM_QUERY, 0, mm_answer_pam_query}, 212 {MONITOR_REQ_PAM_RESPOND, MON_ONCE, mm_answer_pam_respond}, 213 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 214 #endif 215 #ifdef SSH_AUDIT_EVENTS 216 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 217 #endif 218 #ifdef BSD_AUTH 219 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 220 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 221 #endif 222 #ifdef SKEY 223 {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery}, 224 {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond}, 225 #endif 226 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 227 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 228 #ifdef GSSAPI 229 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 230 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx}, 231 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok}, 232 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic}, 233 #endif 234 {0, 0, NULL} 235 }; 236 237 struct mon_table mon_dispatch_postauth20[] = { 238 #ifdef WITH_OPENSSL 239 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 240 #endif 241 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 242 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 243 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 244 {MONITOR_REQ_TERM, 0, mm_answer_term}, 245 #ifdef SSH_AUDIT_EVENTS 246 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 247 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command}, 248 #endif 249 {0, 0, NULL} 250 }; 251 252 struct mon_table *mon_dispatch; 253 254 /* Specifies if a certain message is allowed at the moment */ 255 256 static void 257 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 258 { 259 while (ent->f != NULL) { 260 if (ent->type == type) { 261 ent->flags &= ~MON_PERMIT; 262 ent->flags |= permit ? MON_PERMIT : 0; 263 return; 264 } 265 ent++; 266 } 267 } 268 269 static void 270 monitor_permit_authentications(int permit) 271 { 272 struct mon_table *ent = mon_dispatch; 273 274 while (ent->f != NULL) { 275 if (ent->flags & MON_AUTH) { 276 ent->flags &= ~MON_PERMIT; 277 ent->flags |= permit ? MON_PERMIT : 0; 278 } 279 ent++; 280 } 281 } 282 283 void 284 monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor) 285 { 286 struct mon_table *ent; 287 int authenticated = 0, partial = 0; 288 289 debug3("preauth child monitor started"); 290 291 close(pmonitor->m_recvfd); 292 close(pmonitor->m_log_sendfd); 293 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 294 295 authctxt = _authctxt; 296 memset(authctxt, 0, sizeof(*authctxt)); 297 298 authctxt->loginmsg = &loginmsg; 299 300 mon_dispatch = mon_dispatch_proto20; 301 /* Permit requests for moduli and signatures */ 302 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 303 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 304 305 /* The first few requests do not require asynchronous access */ 306 while (!authenticated) { 307 partial = 0; 308 auth_method = "unknown"; 309 auth_submethod = NULL; 310 authenticated = (monitor_read(pmonitor, mon_dispatch, &ent) == 1); 311 312 /* Special handling for multiple required authentications */ 313 if (options.num_auth_methods != 0) { 314 if (authenticated && 315 !auth2_update_methods_lists(authctxt, 316 auth_method, auth_submethod)) { 317 debug3("%s: method %s: partial", __func__, 318 auth_method); 319 authenticated = 0; 320 partial = 1; 321 } 322 } 323 324 if (authenticated) { 325 if (!(ent->flags & MON_AUTHDECIDE)) 326 fatal("%s: unexpected authentication from %d", 327 __func__, ent->type); 328 if (authctxt->pw->pw_uid == 0 && 329 !auth_root_allowed(auth_method)) 330 authenticated = 0; 331 #ifdef USE_PAM 332 /* PAM needs to perform account checks after auth */ 333 if (options.use_pam && authenticated) { 334 Buffer m; 335 336 buffer_init(&m); 337 mm_request_receive_expect(pmonitor->m_sendfd, 338 MONITOR_REQ_PAM_ACCOUNT, &m); 339 authenticated = mm_answer_pam_account(pmonitor->m_sendfd, &m); 340 buffer_free(&m); 341 } 342 #endif 343 } 344 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 345 auth_log(authctxt, authenticated, partial, 346 auth_method, auth_submethod); 347 if (!partial && !authenticated) 348 authctxt->failures++; 349 } 350 } 351 352 if (!authctxt->valid) 353 fatal("%s: authenticated invalid user", __func__); 354 if (strcmp(auth_method, "unknown") == 0) 355 fatal("%s: authentication method name unknown", __func__); 356 357 debug("%s: %s has been authenticated by privileged process", 358 __func__, authctxt->user); 359 360 mm_get_keystate(pmonitor); 361 362 /* Drain any buffered messages from the child */ 363 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 364 ; 365 366 close(pmonitor->m_sendfd); 367 close(pmonitor->m_log_recvfd); 368 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 369 } 370 371 static void 372 monitor_set_child_handler(pid_t pid) 373 { 374 monitor_child_pid = pid; 375 } 376 377 static void 378 monitor_child_handler(int sig) 379 { 380 kill(monitor_child_pid, sig); 381 } 382 383 void 384 monitor_child_postauth(struct monitor *pmonitor) 385 { 386 close(pmonitor->m_recvfd); 387 pmonitor->m_recvfd = -1; 388 389 monitor_set_child_handler(pmonitor->m_pid); 390 signal(SIGHUP, &monitor_child_handler); 391 signal(SIGTERM, &monitor_child_handler); 392 signal(SIGINT, &monitor_child_handler); 393 #ifdef SIGXFSZ 394 signal(SIGXFSZ, SIG_IGN); 395 #endif 396 397 mon_dispatch = mon_dispatch_postauth20; 398 399 /* Permit requests for moduli and signatures */ 400 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 401 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 402 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 403 404 if (!no_pty_flag) { 405 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 406 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 407 } 408 409 for (;;) 410 monitor_read(pmonitor, mon_dispatch, NULL); 411 } 412 413 static int 414 monitor_read_log(struct monitor *pmonitor) 415 { 416 Buffer logmsg; 417 u_int len, level; 418 char *msg; 419 420 buffer_init(&logmsg); 421 422 /* Read length */ 423 buffer_append_space(&logmsg, 4); 424 if (atomicio(read, pmonitor->m_log_recvfd, 425 buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) { 426 if (errno == EPIPE) { 427 buffer_free(&logmsg); 428 debug("%s: child log fd closed", __func__); 429 close(pmonitor->m_log_recvfd); 430 pmonitor->m_log_recvfd = -1; 431 return -1; 432 } 433 fatal("%s: log fd read: %s", __func__, strerror(errno)); 434 } 435 len = buffer_get_int(&logmsg); 436 if (len <= 4 || len > 8192) 437 fatal("%s: invalid log message length %u", __func__, len); 438 439 /* Read severity, message */ 440 buffer_clear(&logmsg); 441 buffer_append_space(&logmsg, len); 442 if (atomicio(read, pmonitor->m_log_recvfd, 443 buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) 444 fatal("%s: log fd read: %s", __func__, strerror(errno)); 445 446 /* Log it */ 447 level = buffer_get_int(&logmsg); 448 msg = buffer_get_string(&logmsg, NULL); 449 if (log_level_name(level) == NULL) 450 fatal("%s: invalid log level %u (corrupted message?)", 451 __func__, level); 452 do_log2(level, "%s [preauth]", msg); 453 454 buffer_free(&logmsg); 455 free(msg); 456 457 return 0; 458 } 459 460 int 461 monitor_read(struct monitor *pmonitor, struct mon_table *ent, 462 struct mon_table **pent) 463 { 464 Buffer m; 465 int ret; 466 u_char type; 467 struct pollfd pfd[2]; 468 469 for (;;) { 470 memset(&pfd, 0, sizeof(pfd)); 471 pfd[0].fd = pmonitor->m_sendfd; 472 pfd[0].events = POLLIN; 473 pfd[1].fd = pmonitor->m_log_recvfd; 474 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 475 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 476 if (errno == EINTR || errno == EAGAIN) 477 continue; 478 fatal("%s: poll: %s", __func__, strerror(errno)); 479 } 480 if (pfd[1].revents) { 481 /* 482 * Drain all log messages before processing next 483 * monitor request. 484 */ 485 monitor_read_log(pmonitor); 486 continue; 487 } 488 if (pfd[0].revents) 489 break; /* Continues below */ 490 } 491 492 buffer_init(&m); 493 494 mm_request_receive(pmonitor->m_sendfd, &m); 495 type = buffer_get_char(&m); 496 497 debug3("%s: checking request %d", __func__, type); 498 499 while (ent->f != NULL) { 500 if (ent->type == type) 501 break; 502 ent++; 503 } 504 505 if (ent->f != NULL) { 506 if (!(ent->flags & MON_PERMIT)) 507 fatal("%s: unpermitted request %d", __func__, 508 type); 509 ret = (*ent->f)(pmonitor->m_sendfd, &m); 510 buffer_free(&m); 511 512 /* The child may use this request only once, disable it */ 513 if (ent->flags & MON_ONCE) { 514 debug2("%s: %d used once, disabling now", __func__, 515 type); 516 ent->flags &= ~MON_PERMIT; 517 } 518 519 if (pent != NULL) 520 *pent = ent; 521 522 return ret; 523 } 524 525 fatal("%s: unsupported request: %d", __func__, type); 526 527 /* NOTREACHED */ 528 return (-1); 529 } 530 531 /* allowed key state */ 532 static int 533 monitor_allowed_key(u_char *blob, u_int bloblen) 534 { 535 /* make sure key is allowed */ 536 if (key_blob == NULL || key_bloblen != bloblen || 537 timingsafe_bcmp(key_blob, blob, key_bloblen)) 538 return (0); 539 return (1); 540 } 541 542 static void 543 monitor_reset_key_state(void) 544 { 545 /* reset state */ 546 free(key_blob); 547 free(hostbased_cuser); 548 free(hostbased_chost); 549 key_blob = NULL; 550 key_bloblen = 0; 551 key_blobtype = MM_NOKEY; 552 hostbased_cuser = NULL; 553 hostbased_chost = NULL; 554 } 555 556 #ifdef WITH_OPENSSL 557 int 558 mm_answer_moduli(int sock, Buffer *m) 559 { 560 DH *dh; 561 int min, want, max; 562 563 min = buffer_get_int(m); 564 want = buffer_get_int(m); 565 max = buffer_get_int(m); 566 567 debug3("%s: got parameters: %d %d %d", 568 __func__, min, want, max); 569 /* We need to check here, too, in case the child got corrupted */ 570 if (max < min || want < min || max < want) 571 fatal("%s: bad parameters: %d %d %d", 572 __func__, min, want, max); 573 574 buffer_clear(m); 575 576 dh = choose_dh(min, want, max); 577 if (dh == NULL) { 578 buffer_put_char(m, 0); 579 return (0); 580 } else { 581 /* Send first bignum */ 582 buffer_put_char(m, 1); 583 buffer_put_bignum2(m, dh->p); 584 buffer_put_bignum2(m, dh->g); 585 586 DH_free(dh); 587 } 588 mm_request_send(sock, MONITOR_ANS_MODULI, m); 589 return (0); 590 } 591 #endif 592 593 int 594 mm_answer_sign(int sock, Buffer *m) 595 { 596 struct ssh *ssh = active_state; /* XXX */ 597 extern int auth_sock; /* XXX move to state struct? */ 598 struct sshkey *key; 599 struct sshbuf *sigbuf = NULL; 600 u_char *p = NULL, *signature = NULL; 601 char *alg = NULL; 602 size_t datlen, siglen, alglen; 603 int r, is_proof = 0; 604 u_int keyid; 605 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 606 607 debug3("%s", __func__); 608 609 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 610 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 611 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0) 612 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 613 if (keyid > INT_MAX) 614 fatal("%s: invalid key ID", __func__); 615 616 /* 617 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 618 * SHA384 (48 bytes) and SHA512 (64 bytes). 619 * 620 * Otherwise, verify the signature request is for a hostkey 621 * proof. 622 * 623 * XXX perform similar check for KEX signature requests too? 624 * it's not trivial, since what is signed is the hash, rather 625 * than the full kex structure... 626 */ 627 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 628 /* 629 * Construct expected hostkey proof and compare it to what 630 * the client sent us. 631 */ 632 if (session_id2_len == 0) /* hostkeys is never first */ 633 fatal("%s: bad data length: %zu", __func__, datlen); 634 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 635 fatal("%s: no hostkey for index %d", __func__, keyid); 636 if ((sigbuf = sshbuf_new()) == NULL) 637 fatal("%s: sshbuf_new", __func__); 638 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 639 (r = sshbuf_put_string(sigbuf, session_id2, 640 session_id2_len)) != 0 || 641 (r = sshkey_puts(key, sigbuf)) != 0) 642 fatal("%s: couldn't prepare private key " 643 "proof buffer: %s", __func__, ssh_err(r)); 644 if (datlen != sshbuf_len(sigbuf) || 645 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 646 fatal("%s: bad data length: %zu, hostkey proof len %zu", 647 __func__, datlen, sshbuf_len(sigbuf)); 648 sshbuf_free(sigbuf); 649 is_proof = 1; 650 } 651 652 /* save session id, it will be passed on the first call */ 653 if (session_id2_len == 0) { 654 session_id2_len = datlen; 655 session_id2 = xmalloc(session_id2_len); 656 memcpy(session_id2, p, session_id2_len); 657 } 658 659 if ((key = get_hostkey_by_index(keyid)) != NULL) { 660 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 661 datafellows)) != 0) 662 fatal("%s: sshkey_sign failed: %s", 663 __func__, ssh_err(r)); 664 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 665 auth_sock > 0) { 666 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 667 p, datlen, alg, datafellows)) != 0) { 668 fatal("%s: ssh_agent_sign failed: %s", 669 __func__, ssh_err(r)); 670 } 671 } else 672 fatal("%s: no hostkey from index %d", __func__, keyid); 673 674 debug3("%s: %s signature %p(%zu)", __func__, 675 is_proof ? "KEX" : "hostkey proof", signature, siglen); 676 677 sshbuf_reset(m); 678 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 679 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 680 681 free(alg); 682 free(p); 683 free(signature); 684 685 mm_request_send(sock, MONITOR_ANS_SIGN, m); 686 687 /* Turn on permissions for getpwnam */ 688 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 689 690 return (0); 691 } 692 693 /* Retrieves the password entry and also checks if the user is permitted */ 694 695 int 696 mm_answer_pwnamallow(int sock, Buffer *m) 697 { 698 char *username; 699 struct passwd *pwent; 700 int allowed = 0; 701 u_int i; 702 703 debug3("%s", __func__); 704 705 if (authctxt->attempt++ != 0) 706 fatal("%s: multiple attempts for getpwnam", __func__); 707 708 username = buffer_get_string(m, NULL); 709 710 pwent = getpwnamallow(username); 711 712 authctxt->user = xstrdup(username); 713 setproctitle("%s [priv]", pwent ? username : "unknown"); 714 free(username); 715 716 buffer_clear(m); 717 718 if (pwent == NULL) { 719 buffer_put_char(m, 0); 720 authctxt->pw = fakepw(); 721 goto out; 722 } 723 724 allowed = 1; 725 authctxt->pw = pwent; 726 authctxt->valid = 1; 727 728 buffer_put_char(m, 1); 729 buffer_put_string(m, pwent, sizeof(struct passwd)); 730 buffer_put_cstring(m, pwent->pw_name); 731 buffer_put_cstring(m, "*"); 732 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS 733 buffer_put_cstring(m, pwent->pw_gecos); 734 #endif 735 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS 736 buffer_put_cstring(m, pwent->pw_class); 737 #endif 738 buffer_put_cstring(m, pwent->pw_dir); 739 buffer_put_cstring(m, pwent->pw_shell); 740 741 out: 742 buffer_put_string(m, &options, sizeof(options)); 743 744 #define M_CP_STROPT(x) do { \ 745 if (options.x != NULL) \ 746 buffer_put_cstring(m, options.x); \ 747 } while (0) 748 #define M_CP_STRARRAYOPT(x, nx) do { \ 749 for (i = 0; i < options.nx; i++) \ 750 buffer_put_cstring(m, options.x[i]); \ 751 } while (0) 752 /* See comment in servconf.h */ 753 COPY_MATCH_STRING_OPTS(); 754 #undef M_CP_STROPT 755 #undef M_CP_STRARRAYOPT 756 757 /* Create valid auth method lists */ 758 if (auth2_setup_methods_lists(authctxt) != 0) { 759 /* 760 * The monitor will continue long enough to let the child 761 * run to it's packet_disconnect(), but it must not allow any 762 * authentication to succeed. 763 */ 764 debug("%s: no valid authentication method lists", __func__); 765 } 766 767 debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed); 768 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 769 770 /* Allow service/style information on the auth context */ 771 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 772 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 773 774 #ifdef USE_PAM 775 if (options.use_pam) 776 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); 777 #endif 778 779 return (0); 780 } 781 782 int mm_answer_auth2_read_banner(int sock, Buffer *m) 783 { 784 char *banner; 785 786 buffer_clear(m); 787 banner = auth2_read_banner(); 788 buffer_put_cstring(m, banner != NULL ? banner : ""); 789 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 790 free(banner); 791 792 return (0); 793 } 794 795 int 796 mm_answer_authserv(int sock, Buffer *m) 797 { 798 monitor_permit_authentications(1); 799 800 authctxt->service = buffer_get_string(m, NULL); 801 authctxt->style = buffer_get_string(m, NULL); 802 debug3("%s: service=%s, style=%s", 803 __func__, authctxt->service, authctxt->style); 804 805 if (strlen(authctxt->style) == 0) { 806 free(authctxt->style); 807 authctxt->style = NULL; 808 } 809 810 return (0); 811 } 812 813 int 814 mm_answer_authpassword(int sock, Buffer *m) 815 { 816 static int call_count; 817 char *passwd; 818 int authenticated; 819 u_int plen; 820 821 if (!options.password_authentication) 822 fatal("%s: password authentication not enabled", __func__); 823 passwd = buffer_get_string(m, &plen); 824 /* Only authenticate if the context is valid */ 825 authenticated = options.password_authentication && 826 auth_password(authctxt, passwd); 827 explicit_bzero(passwd, strlen(passwd)); 828 free(passwd); 829 830 buffer_clear(m); 831 buffer_put_int(m, authenticated); 832 #ifdef USE_PAM 833 buffer_put_int(m, sshpam_get_maxtries_reached()); 834 #endif 835 836 debug3("%s: sending result %d", __func__, authenticated); 837 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 838 839 call_count++; 840 if (plen == 0 && call_count == 1) 841 auth_method = "none"; 842 else 843 auth_method = "password"; 844 845 /* Causes monitor loop to terminate if authenticated */ 846 return (authenticated); 847 } 848 849 #ifdef BSD_AUTH 850 int 851 mm_answer_bsdauthquery(int sock, Buffer *m) 852 { 853 char *name, *infotxt; 854 u_int numprompts; 855 u_int *echo_on; 856 char **prompts; 857 u_int success; 858 859 if (!options.kbd_interactive_authentication) 860 fatal("%s: kbd-int authentication not enabled", __func__); 861 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 862 &prompts, &echo_on) < 0 ? 0 : 1; 863 864 buffer_clear(m); 865 buffer_put_int(m, success); 866 if (success) 867 buffer_put_cstring(m, prompts[0]); 868 869 debug3("%s: sending challenge success: %u", __func__, success); 870 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 871 872 if (success) { 873 free(name); 874 free(infotxt); 875 free(prompts); 876 free(echo_on); 877 } 878 879 return (0); 880 } 881 882 int 883 mm_answer_bsdauthrespond(int sock, Buffer *m) 884 { 885 char *response; 886 int authok; 887 888 if (!options.kbd_interactive_authentication) 889 fatal("%s: kbd-int authentication not enabled", __func__); 890 if (authctxt->as == NULL) 891 fatal("%s: no bsd auth session", __func__); 892 893 response = buffer_get_string(m, NULL); 894 authok = options.challenge_response_authentication && 895 auth_userresponse(authctxt->as, response, 0); 896 authctxt->as = NULL; 897 debug3("%s: <%s> = <%d>", __func__, response, authok); 898 free(response); 899 900 buffer_clear(m); 901 buffer_put_int(m, authok); 902 903 debug3("%s: sending authenticated: %d", __func__, authok); 904 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 905 906 auth_method = "keyboard-interactive"; 907 auth_submethod = "bsdauth"; 908 909 return (authok != 0); 910 } 911 #endif 912 913 #ifdef SKEY 914 int 915 mm_answer_skeyquery(int sock, Buffer *m) 916 { 917 struct skey skey; 918 char challenge[1024]; 919 u_int success; 920 921 success = _compat_skeychallenge(&skey, authctxt->user, challenge, 922 sizeof(challenge)) < 0 ? 0 : 1; 923 924 buffer_clear(m); 925 buffer_put_int(m, success); 926 if (success) 927 buffer_put_cstring(m, challenge); 928 929 debug3("%s: sending challenge success: %u", __func__, success); 930 mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m); 931 932 return (0); 933 } 934 935 int 936 mm_answer_skeyrespond(int sock, Buffer *m) 937 { 938 char *response; 939 int authok; 940 941 response = buffer_get_string(m, NULL); 942 943 authok = (options.challenge_response_authentication && 944 authctxt->valid && 945 skey_haskey(authctxt->pw->pw_name) == 0 && 946 skey_passcheck(authctxt->pw->pw_name, response) != -1); 947 948 free(response); 949 950 buffer_clear(m); 951 buffer_put_int(m, authok); 952 953 debug3("%s: sending authenticated: %d", __func__, authok); 954 mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m); 955 956 auth_method = "keyboard-interactive"; 957 auth_submethod = "skey"; 958 959 return (authok != 0); 960 } 961 #endif 962 963 #ifdef USE_PAM 964 int 965 mm_answer_pam_start(int sock, Buffer *m) 966 { 967 if (!options.use_pam) 968 fatal("UsePAM not set, but ended up in %s anyway", __func__); 969 970 start_pam(authctxt); 971 972 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); 973 if (options.kbd_interactive_authentication) 974 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 975 976 return (0); 977 } 978 979 int 980 mm_answer_pam_account(int sock, Buffer *m) 981 { 982 u_int ret; 983 984 if (!options.use_pam) 985 fatal("%s: PAM not enabled", __func__); 986 987 ret = do_pam_account(); 988 989 buffer_put_int(m, ret); 990 buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg)); 991 992 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m); 993 994 return (ret); 995 } 996 997 static void *sshpam_ctxt, *sshpam_authok; 998 extern KbdintDevice sshpam_device; 999 1000 int 1001 mm_answer_pam_init_ctx(int sock, Buffer *m) 1002 { 1003 debug3("%s", __func__); 1004 if (!options.kbd_interactive_authentication) 1005 fatal("%s: kbd-int authentication not enabled", __func__); 1006 if (sshpam_ctxt != NULL) 1007 fatal("%s: already called", __func__); 1008 sshpam_ctxt = (sshpam_device.init_ctx)(authctxt); 1009 sshpam_authok = NULL; 1010 buffer_clear(m); 1011 if (sshpam_ctxt != NULL) { 1012 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 1013 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_QUERY, 1); 1014 buffer_put_int(m, 1); 1015 } else { 1016 buffer_put_int(m, 0); 1017 } 1018 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); 1019 return (0); 1020 } 1021 1022 int 1023 mm_answer_pam_query(int sock, Buffer *m) 1024 { 1025 char *name = NULL, *info = NULL, **prompts = NULL; 1026 u_int i, num = 0, *echo_on = 0; 1027 int ret; 1028 1029 debug3("%s", __func__); 1030 sshpam_authok = NULL; 1031 if (sshpam_ctxt == NULL) 1032 fatal("%s: no context", __func__); 1033 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, 1034 &num, &prompts, &echo_on); 1035 if (ret == 0 && num == 0) 1036 sshpam_authok = sshpam_ctxt; 1037 if (num > 1 || name == NULL || info == NULL) 1038 fatal("sshpam_device.query failed"); 1039 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_RESPOND, 1); 1040 buffer_clear(m); 1041 buffer_put_int(m, ret); 1042 buffer_put_cstring(m, name); 1043 free(name); 1044 buffer_put_cstring(m, info); 1045 free(info); 1046 buffer_put_int(m, sshpam_get_maxtries_reached()); 1047 buffer_put_int(m, num); 1048 for (i = 0; i < num; ++i) { 1049 buffer_put_cstring(m, prompts[i]); 1050 free(prompts[i]); 1051 buffer_put_int(m, echo_on[i]); 1052 } 1053 free(prompts); 1054 free(echo_on); 1055 auth_method = "keyboard-interactive"; 1056 auth_submethod = "pam"; 1057 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m); 1058 return (0); 1059 } 1060 1061 int 1062 mm_answer_pam_respond(int sock, Buffer *m) 1063 { 1064 char **resp; 1065 u_int i, num; 1066 int ret; 1067 1068 debug3("%s", __func__); 1069 if (sshpam_ctxt == NULL) 1070 fatal("%s: no context", __func__); 1071 sshpam_authok = NULL; 1072 num = buffer_get_int(m); 1073 if (num > 0) { 1074 resp = xcalloc(num, sizeof(char *)); 1075 for (i = 0; i < num; ++i) 1076 resp[i] = buffer_get_string(m, NULL); 1077 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp); 1078 for (i = 0; i < num; ++i) 1079 free(resp[i]); 1080 free(resp); 1081 } else { 1082 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL); 1083 } 1084 buffer_clear(m); 1085 buffer_put_int(m, ret); 1086 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m); 1087 auth_method = "keyboard-interactive"; 1088 auth_submethod = "pam"; 1089 if (ret == 0) 1090 sshpam_authok = sshpam_ctxt; 1091 return (0); 1092 } 1093 1094 int 1095 mm_answer_pam_free_ctx(int sock, Buffer *m) 1096 { 1097 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt; 1098 1099 debug3("%s", __func__); 1100 if (sshpam_ctxt == NULL) 1101 fatal("%s: no context", __func__); 1102 (sshpam_device.free_ctx)(sshpam_ctxt); 1103 sshpam_ctxt = sshpam_authok = NULL; 1104 buffer_clear(m); 1105 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); 1106 /* Allow another attempt */ 1107 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 1108 auth_method = "keyboard-interactive"; 1109 auth_submethod = "pam"; 1110 return r; 1111 } 1112 #endif 1113 1114 int 1115 mm_answer_keyallowed(int sock, Buffer *m) 1116 { 1117 Key *key; 1118 char *cuser, *chost; 1119 u_char *blob; 1120 u_int bloblen, pubkey_auth_attempt; 1121 enum mm_keytype type = 0; 1122 int allowed = 0; 1123 1124 debug3("%s entering", __func__); 1125 1126 type = buffer_get_int(m); 1127 cuser = buffer_get_string(m, NULL); 1128 chost = buffer_get_string(m, NULL); 1129 blob = buffer_get_string(m, &bloblen); 1130 pubkey_auth_attempt = buffer_get_int(m); 1131 1132 key = key_from_blob(blob, bloblen); 1133 1134 debug3("%s: key_from_blob: %p", __func__, key); 1135 1136 if (key != NULL && authctxt->valid) { 1137 /* These should not make it past the privsep child */ 1138 if (key_type_plain(key->type) == KEY_RSA && 1139 (datafellows & SSH_BUG_RSASIGMD5) != 0) 1140 fatal("%s: passed a SSH_BUG_RSASIGMD5 key", __func__); 1141 1142 switch (type) { 1143 case MM_USERKEY: 1144 allowed = options.pubkey_authentication && 1145 !auth2_userkey_already_used(authctxt, key) && 1146 match_pattern_list(sshkey_ssh_name(key), 1147 options.pubkey_key_types, 0) == 1 && 1148 user_key_allowed(authctxt->pw, key, 1149 pubkey_auth_attempt); 1150 pubkey_auth_info(authctxt, key, NULL); 1151 auth_method = "publickey"; 1152 if (options.pubkey_authentication && 1153 (!pubkey_auth_attempt || allowed != 1)) 1154 auth_clear_options(); 1155 break; 1156 case MM_HOSTKEY: 1157 allowed = options.hostbased_authentication && 1158 match_pattern_list(sshkey_ssh_name(key), 1159 options.hostbased_key_types, 0) == 1 && 1160 hostbased_key_allowed(authctxt->pw, 1161 cuser, chost, key); 1162 pubkey_auth_info(authctxt, key, 1163 "client user \"%.100s\", client host \"%.100s\"", 1164 cuser, chost); 1165 auth_method = "hostbased"; 1166 break; 1167 default: 1168 fatal("%s: unknown key type %d", __func__, type); 1169 break; 1170 } 1171 } 1172 1173 debug3("%s: key %p is %s", 1174 __func__, key, allowed ? "allowed" : "not allowed"); 1175 1176 if (key != NULL) 1177 key_free(key); 1178 1179 /* clear temporarily storage (used by verify) */ 1180 monitor_reset_key_state(); 1181 1182 if (allowed) { 1183 /* Save temporarily for comparison in verify */ 1184 key_blob = blob; 1185 key_bloblen = bloblen; 1186 key_blobtype = type; 1187 hostbased_cuser = cuser; 1188 hostbased_chost = chost; 1189 } else { 1190 /* Log failed attempt */ 1191 auth_log(authctxt, 0, 0, auth_method, NULL); 1192 free(blob); 1193 free(cuser); 1194 free(chost); 1195 } 1196 1197 buffer_clear(m); 1198 buffer_put_int(m, allowed); 1199 buffer_put_int(m, forced_command != NULL); 1200 1201 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 1202 1203 return (0); 1204 } 1205 1206 static int 1207 monitor_valid_userblob(u_char *data, u_int datalen) 1208 { 1209 Buffer b; 1210 u_char *p; 1211 char *userstyle, *cp; 1212 u_int len; 1213 int fail = 0; 1214 1215 buffer_init(&b); 1216 buffer_append(&b, data, datalen); 1217 1218 if (datafellows & SSH_OLD_SESSIONID) { 1219 p = buffer_ptr(&b); 1220 len = buffer_len(&b); 1221 if ((session_id2 == NULL) || 1222 (len < session_id2_len) || 1223 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1224 fail++; 1225 buffer_consume(&b, session_id2_len); 1226 } else { 1227 p = buffer_get_string(&b, &len); 1228 if ((session_id2 == NULL) || 1229 (len != session_id2_len) || 1230 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1231 fail++; 1232 free(p); 1233 } 1234 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 1235 fail++; 1236 cp = buffer_get_cstring(&b, NULL); 1237 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1238 authctxt->style ? ":" : "", 1239 authctxt->style ? authctxt->style : ""); 1240 if (strcmp(userstyle, cp) != 0) { 1241 logit("wrong user name passed to monitor: " 1242 "expected %s != %.100s", userstyle, cp); 1243 fail++; 1244 } 1245 free(userstyle); 1246 free(cp); 1247 buffer_skip_string(&b); 1248 if (datafellows & SSH_BUG_PKAUTH) { 1249 if (!buffer_get_char(&b)) 1250 fail++; 1251 } else { 1252 cp = buffer_get_cstring(&b, NULL); 1253 if (strcmp("publickey", cp) != 0) 1254 fail++; 1255 free(cp); 1256 if (!buffer_get_char(&b)) 1257 fail++; 1258 buffer_skip_string(&b); 1259 } 1260 buffer_skip_string(&b); 1261 if (buffer_len(&b) != 0) 1262 fail++; 1263 buffer_free(&b); 1264 return (fail == 0); 1265 } 1266 1267 static int 1268 monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser, 1269 char *chost) 1270 { 1271 Buffer b; 1272 char *p, *userstyle; 1273 u_int len; 1274 int fail = 0; 1275 1276 buffer_init(&b); 1277 buffer_append(&b, data, datalen); 1278 1279 p = buffer_get_string(&b, &len); 1280 if ((session_id2 == NULL) || 1281 (len != session_id2_len) || 1282 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1283 fail++; 1284 free(p); 1285 1286 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 1287 fail++; 1288 p = buffer_get_cstring(&b, NULL); 1289 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1290 authctxt->style ? ":" : "", 1291 authctxt->style ? authctxt->style : ""); 1292 if (strcmp(userstyle, p) != 0) { 1293 logit("wrong user name passed to monitor: expected %s != %.100s", 1294 userstyle, p); 1295 fail++; 1296 } 1297 free(userstyle); 1298 free(p); 1299 buffer_skip_string(&b); /* service */ 1300 p = buffer_get_cstring(&b, NULL); 1301 if (strcmp(p, "hostbased") != 0) 1302 fail++; 1303 free(p); 1304 buffer_skip_string(&b); /* pkalg */ 1305 buffer_skip_string(&b); /* pkblob */ 1306 1307 /* verify client host, strip trailing dot if necessary */ 1308 p = buffer_get_string(&b, NULL); 1309 if (((len = strlen(p)) > 0) && p[len - 1] == '.') 1310 p[len - 1] = '\0'; 1311 if (strcmp(p, chost) != 0) 1312 fail++; 1313 free(p); 1314 1315 /* verify client user */ 1316 p = buffer_get_string(&b, NULL); 1317 if (strcmp(p, cuser) != 0) 1318 fail++; 1319 free(p); 1320 1321 if (buffer_len(&b) != 0) 1322 fail++; 1323 buffer_free(&b); 1324 return (fail == 0); 1325 } 1326 1327 int 1328 mm_answer_keyverify(int sock, Buffer *m) 1329 { 1330 Key *key; 1331 u_char *signature, *data, *blob; 1332 u_int signaturelen, datalen, bloblen; 1333 int verified = 0; 1334 int valid_data = 0; 1335 1336 blob = buffer_get_string(m, &bloblen); 1337 signature = buffer_get_string(m, &signaturelen); 1338 data = buffer_get_string(m, &datalen); 1339 1340 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1341 !monitor_allowed_key(blob, bloblen)) 1342 fatal("%s: bad key, not previously allowed", __func__); 1343 1344 key = key_from_blob(blob, bloblen); 1345 if (key == NULL) 1346 fatal("%s: bad public key blob", __func__); 1347 1348 switch (key_blobtype) { 1349 case MM_USERKEY: 1350 valid_data = monitor_valid_userblob(data, datalen); 1351 break; 1352 case MM_HOSTKEY: 1353 valid_data = monitor_valid_hostbasedblob(data, datalen, 1354 hostbased_cuser, hostbased_chost); 1355 break; 1356 default: 1357 valid_data = 0; 1358 break; 1359 } 1360 if (!valid_data) 1361 fatal("%s: bad signature data blob", __func__); 1362 1363 verified = key_verify(key, signature, signaturelen, data, datalen); 1364 debug3("%s: key %p signature %s", 1365 __func__, key, (verified == 1) ? "verified" : "unverified"); 1366 1367 /* If auth was successful then record key to ensure it isn't reused */ 1368 if (verified == 1 && key_blobtype == MM_USERKEY) 1369 auth2_record_userkey(authctxt, key); 1370 else 1371 key_free(key); 1372 1373 free(blob); 1374 free(signature); 1375 free(data); 1376 1377 auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased"; 1378 1379 monitor_reset_key_state(); 1380 1381 buffer_clear(m); 1382 buffer_put_int(m, verified); 1383 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1384 1385 return (verified == 1); 1386 } 1387 1388 static void 1389 mm_record_login(Session *s, struct passwd *pw) 1390 { 1391 struct ssh *ssh = active_state; /* XXX */ 1392 socklen_t fromlen; 1393 struct sockaddr_storage from; 1394 1395 /* 1396 * Get IP address of client. If the connection is not a socket, let 1397 * the address be 0.0.0.0. 1398 */ 1399 memset(&from, 0, sizeof(from)); 1400 fromlen = sizeof(from); 1401 if (packet_connection_is_on_socket()) { 1402 if (getpeername(packet_get_connection_in(), 1403 (struct sockaddr *)&from, &fromlen) < 0) { 1404 debug("getpeername: %.100s", strerror(errno)); 1405 cleanup_exit(255); 1406 } 1407 } 1408 /* Record that there was a login on that tty from the remote host. */ 1409 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1410 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1411 (struct sockaddr *)&from, fromlen); 1412 } 1413 1414 static void 1415 mm_session_close(Session *s) 1416 { 1417 debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid); 1418 if (s->ttyfd != -1) { 1419 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd); 1420 session_pty_cleanup2(s); 1421 } 1422 session_unused(s->self); 1423 } 1424 1425 int 1426 mm_answer_pty(int sock, Buffer *m) 1427 { 1428 extern struct monitor *pmonitor; 1429 Session *s; 1430 int res, fd0; 1431 1432 debug3("%s entering", __func__); 1433 1434 buffer_clear(m); 1435 s = session_new(); 1436 if (s == NULL) 1437 goto error; 1438 s->authctxt = authctxt; 1439 s->pw = authctxt->pw; 1440 s->pid = pmonitor->m_pid; 1441 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1442 if (res == 0) 1443 goto error; 1444 pty_setowner(authctxt->pw, s->tty); 1445 1446 buffer_put_int(m, 1); 1447 buffer_put_cstring(m, s->tty); 1448 1449 /* We need to trick ttyslot */ 1450 if (dup2(s->ttyfd, 0) == -1) 1451 fatal("%s: dup2", __func__); 1452 1453 mm_record_login(s, authctxt->pw); 1454 1455 /* Now we can close the file descriptor again */ 1456 close(0); 1457 1458 /* send messages generated by record_login */ 1459 buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg)); 1460 buffer_clear(&loginmsg); 1461 1462 mm_request_send(sock, MONITOR_ANS_PTY, m); 1463 1464 if (mm_send_fd(sock, s->ptyfd) == -1 || 1465 mm_send_fd(sock, s->ttyfd) == -1) 1466 fatal("%s: send fds failed", __func__); 1467 1468 /* make sure nothing uses fd 0 */ 1469 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0) 1470 fatal("%s: open(/dev/null): %s", __func__, strerror(errno)); 1471 if (fd0 != 0) 1472 error("%s: fd0 %d != 0", __func__, fd0); 1473 1474 /* slave is not needed */ 1475 close(s->ttyfd); 1476 s->ttyfd = s->ptyfd; 1477 /* no need to dup() because nobody closes ptyfd */ 1478 s->ptymaster = s->ptyfd; 1479 1480 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd); 1481 1482 return (0); 1483 1484 error: 1485 if (s != NULL) 1486 mm_session_close(s); 1487 buffer_put_int(m, 0); 1488 mm_request_send(sock, MONITOR_ANS_PTY, m); 1489 return (0); 1490 } 1491 1492 int 1493 mm_answer_pty_cleanup(int sock, Buffer *m) 1494 { 1495 Session *s; 1496 char *tty; 1497 1498 debug3("%s entering", __func__); 1499 1500 tty = buffer_get_string(m, NULL); 1501 if ((s = session_by_tty(tty)) != NULL) 1502 mm_session_close(s); 1503 buffer_clear(m); 1504 free(tty); 1505 return (0); 1506 } 1507 1508 int 1509 mm_answer_term(int sock, Buffer *req) 1510 { 1511 extern struct monitor *pmonitor; 1512 int res, status; 1513 1514 debug3("%s: tearing down sessions", __func__); 1515 1516 /* The child is terminating */ 1517 session_destroy_all(&mm_session_close); 1518 1519 #ifdef USE_PAM 1520 if (options.use_pam) 1521 sshpam_cleanup(); 1522 #endif 1523 1524 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1525 if (errno != EINTR) 1526 exit(1); 1527 1528 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1529 1530 /* Terminate process */ 1531 exit(res); 1532 } 1533 1534 #ifdef SSH_AUDIT_EVENTS 1535 /* Report that an audit event occurred */ 1536 int 1537 mm_answer_audit_event(int socket, Buffer *m) 1538 { 1539 ssh_audit_event_t event; 1540 1541 debug3("%s entering", __func__); 1542 1543 event = buffer_get_int(m); 1544 switch(event) { 1545 case SSH_AUTH_FAIL_PUBKEY: 1546 case SSH_AUTH_FAIL_HOSTBASED: 1547 case SSH_AUTH_FAIL_GSSAPI: 1548 case SSH_LOGIN_EXCEED_MAXTRIES: 1549 case SSH_LOGIN_ROOT_DENIED: 1550 case SSH_CONNECTION_CLOSE: 1551 case SSH_INVALID_USER: 1552 audit_event(event); 1553 break; 1554 default: 1555 fatal("Audit event type %d not permitted", event); 1556 } 1557 1558 return (0); 1559 } 1560 1561 int 1562 mm_answer_audit_command(int socket, Buffer *m) 1563 { 1564 u_int len; 1565 char *cmd; 1566 1567 debug3("%s entering", __func__); 1568 cmd = buffer_get_string(m, &len); 1569 /* sanity check command, if so how? */ 1570 audit_run_command(cmd); 1571 free(cmd); 1572 return (0); 1573 } 1574 #endif /* SSH_AUDIT_EVENTS */ 1575 1576 void 1577 monitor_apply_keystate(struct monitor *pmonitor) 1578 { 1579 struct ssh *ssh = active_state; /* XXX */ 1580 struct kex *kex; 1581 int r; 1582 1583 debug3("%s: packet_set_state", __func__); 1584 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1585 fatal("%s: packet_set_state: %s", __func__, ssh_err(r)); 1586 sshbuf_free(child_state); 1587 child_state = NULL; 1588 1589 if ((kex = ssh->kex) != NULL) { 1590 /* XXX set callbacks */ 1591 #ifdef WITH_OPENSSL 1592 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; 1593 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; 1594 kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server; 1595 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server; 1596 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server; 1597 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1598 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1599 # ifdef OPENSSL_HAS_ECC 1600 kex->kex[KEX_ECDH_SHA2] = kexecdh_server; 1601 # endif 1602 #endif /* WITH_OPENSSL */ 1603 kex->kex[KEX_C25519_SHA256] = kexc25519_server; 1604 kex->load_host_public_key=&get_hostkey_public_by_type; 1605 kex->load_host_private_key=&get_hostkey_private_by_type; 1606 kex->host_key_index=&get_hostkey_index; 1607 kex->sign = sshd_hostkey_sign; 1608 } 1609 } 1610 1611 /* This function requries careful sanity checking */ 1612 1613 void 1614 mm_get_keystate(struct monitor *pmonitor) 1615 { 1616 debug3("%s: Waiting for new keys", __func__); 1617 1618 if ((child_state = sshbuf_new()) == NULL) 1619 fatal("%s: sshbuf_new failed", __func__); 1620 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1621 child_state); 1622 debug3("%s: GOT new keys", __func__); 1623 } 1624 1625 1626 /* XXX */ 1627 1628 #define FD_CLOSEONEXEC(x) do { \ 1629 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1630 fatal("fcntl(%d, F_SETFD)", x); \ 1631 } while (0) 1632 1633 static void 1634 monitor_openfds(struct monitor *mon, int do_logfds) 1635 { 1636 int pair[2]; 1637 1638 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1639 fatal("%s: socketpair: %s", __func__, strerror(errno)); 1640 FD_CLOSEONEXEC(pair[0]); 1641 FD_CLOSEONEXEC(pair[1]); 1642 mon->m_recvfd = pair[0]; 1643 mon->m_sendfd = pair[1]; 1644 1645 if (do_logfds) { 1646 if (pipe(pair) == -1) 1647 fatal("%s: pipe: %s", __func__, strerror(errno)); 1648 FD_CLOSEONEXEC(pair[0]); 1649 FD_CLOSEONEXEC(pair[1]); 1650 mon->m_log_recvfd = pair[0]; 1651 mon->m_log_sendfd = pair[1]; 1652 } else 1653 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1654 } 1655 1656 #define MM_MEMSIZE 65536 1657 1658 struct monitor * 1659 monitor_init(void) 1660 { 1661 struct monitor *mon; 1662 1663 mon = xcalloc(1, sizeof(*mon)); 1664 monitor_openfds(mon, 1); 1665 1666 return mon; 1667 } 1668 1669 void 1670 monitor_reinit(struct monitor *mon) 1671 { 1672 monitor_openfds(mon, 0); 1673 } 1674 1675 #ifdef GSSAPI 1676 int 1677 mm_answer_gss_setup_ctx(int sock, Buffer *m) 1678 { 1679 gss_OID_desc goid; 1680 OM_uint32 major; 1681 u_int len; 1682 1683 if (!options.gss_authentication) 1684 fatal("%s: GSSAPI authentication not enabled", __func__); 1685 1686 goid.elements = buffer_get_string(m, &len); 1687 goid.length = len; 1688 1689 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1690 1691 free(goid.elements); 1692 1693 buffer_clear(m); 1694 buffer_put_int(m, major); 1695 1696 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1697 1698 /* Now we have a context, enable the step */ 1699 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1700 1701 return (0); 1702 } 1703 1704 int 1705 mm_answer_gss_accept_ctx(int sock, Buffer *m) 1706 { 1707 gss_buffer_desc in; 1708 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1709 OM_uint32 major, minor; 1710 OM_uint32 flags = 0; /* GSI needs this */ 1711 u_int len; 1712 1713 if (!options.gss_authentication) 1714 fatal("%s: GSSAPI authentication not enabled", __func__); 1715 1716 in.value = buffer_get_string(m, &len); 1717 in.length = len; 1718 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1719 free(in.value); 1720 1721 buffer_clear(m); 1722 buffer_put_int(m, major); 1723 buffer_put_string(m, out.value, out.length); 1724 buffer_put_int(m, flags); 1725 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1726 1727 gss_release_buffer(&minor, &out); 1728 1729 if (major == GSS_S_COMPLETE) { 1730 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1731 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1732 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1733 } 1734 return (0); 1735 } 1736 1737 int 1738 mm_answer_gss_checkmic(int sock, Buffer *m) 1739 { 1740 gss_buffer_desc gssbuf, mic; 1741 OM_uint32 ret; 1742 u_int len; 1743 1744 if (!options.gss_authentication) 1745 fatal("%s: GSSAPI authentication not enabled", __func__); 1746 1747 gssbuf.value = buffer_get_string(m, &len); 1748 gssbuf.length = len; 1749 mic.value = buffer_get_string(m, &len); 1750 mic.length = len; 1751 1752 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1753 1754 free(gssbuf.value); 1755 free(mic.value); 1756 1757 buffer_clear(m); 1758 buffer_put_int(m, ret); 1759 1760 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1761 1762 if (!GSS_ERROR(ret)) 1763 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1764 1765 return (0); 1766 } 1767 1768 int 1769 mm_answer_gss_userok(int sock, Buffer *m) 1770 { 1771 int authenticated; 1772 1773 if (!options.gss_authentication) 1774 fatal("%s: GSSAPI authentication not enabled", __func__); 1775 1776 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1777 1778 buffer_clear(m); 1779 buffer_put_int(m, authenticated); 1780 1781 debug3("%s: sending result %d", __func__, authenticated); 1782 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1783 1784 auth_method = "gssapi-with-mic"; 1785 1786 /* Monitor loop will terminate if authenticated */ 1787 return (authenticated); 1788 } 1789 #endif /* GSSAPI */ 1790 1791