1 /* $OpenBSD: monitor.c,v 1.247 2024/12/03 22:30:03 jsg 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 <sys/wait.h> 33 34 #include <errno.h> 35 #include <fcntl.h> 36 #include <limits.h> 37 #ifdef HAVE_PATHS_H 38 #include <paths.h> 39 #endif 40 #include <pwd.h> 41 #include <signal.h> 42 #ifdef HAVE_STDINT_H 43 # include <stdint.h> 44 #endif 45 #include <stdlib.h> 46 #include <string.h> 47 #include <stdarg.h> 48 #include <stdio.h> 49 #include <unistd.h> 50 #ifdef HAVE_POLL_H 51 #include <poll.h> 52 #else 53 # ifdef HAVE_SYS_POLL_H 54 # include <sys/poll.h> 55 # endif 56 #endif 57 58 #ifdef WITH_OPENSSL 59 #include <openssl/dh.h> 60 #endif 61 62 #include "openbsd-compat/sys-tree.h" 63 #include "openbsd-compat/sys-queue.h" 64 #include "openbsd-compat/openssl-compat.h" 65 66 #include "atomicio.h" 67 #include "xmalloc.h" 68 #include "ssh.h" 69 #include "sshkey.h" 70 #include "sshbuf.h" 71 #include "hostfile.h" 72 #include "auth.h" 73 #include "cipher.h" 74 #include "kex.h" 75 #include "dh.h" 76 #include "auth-pam.h" 77 #include "packet.h" 78 #include "auth-options.h" 79 #include "sshpty.h" 80 #include "channels.h" 81 #include "session.h" 82 #include "sshlogin.h" 83 #include "canohost.h" 84 #include "log.h" 85 #include "misc.h" 86 #include "servconf.h" 87 #include "monitor.h" 88 #include "blacklist_client.h" 89 90 #ifdef GSSAPI 91 #include "ssh-gss.h" 92 #endif 93 #include "monitor_wrap.h" 94 #include "monitor_fdpass.h" 95 #include "compat.h" 96 #include "ssh2.h" 97 #include "authfd.h" 98 #include "match.h" 99 #include "ssherr.h" 100 #include "sk-api.h" 101 #include "srclimit.h" 102 103 #ifdef GSSAPI 104 static Gssctxt *gsscontext = NULL; 105 #endif 106 107 /* Imports */ 108 extern ServerOptions options; 109 extern u_int utmp_len; 110 extern struct sshbuf *cfg; 111 extern struct sshbuf *loginmsg; 112 extern struct include_list includes; 113 extern struct sshauthopt *auth_opts; /* XXX move to permanent ssh->authctxt? */ 114 115 /* State exported from the child */ 116 static struct sshbuf *child_state; 117 118 /* Functions on the monitor that answer unprivileged requests */ 119 120 int mm_answer_moduli(struct ssh *, int, struct sshbuf *); 121 int mm_answer_sign(struct ssh *, int, struct sshbuf *); 122 int mm_answer_pwnamallow(struct ssh *, int, struct sshbuf *); 123 int mm_answer_auth2_read_banner(struct ssh *, int, struct sshbuf *); 124 int mm_answer_authserv(struct ssh *, int, struct sshbuf *); 125 int mm_answer_authpassword(struct ssh *, int, struct sshbuf *); 126 int mm_answer_bsdauthquery(struct ssh *, int, struct sshbuf *); 127 int mm_answer_bsdauthrespond(struct ssh *, int, struct sshbuf *); 128 int mm_answer_keyallowed(struct ssh *, int, struct sshbuf *); 129 int mm_answer_keyverify(struct ssh *, int, struct sshbuf *); 130 int mm_answer_pty(struct ssh *, int, struct sshbuf *); 131 int mm_answer_pty_cleanup(struct ssh *, int, struct sshbuf *); 132 int mm_answer_term(struct ssh *, int, struct sshbuf *); 133 int mm_answer_state(struct ssh *, int, struct sshbuf *); 134 135 #ifdef USE_PAM 136 int mm_answer_pam_start(struct ssh *, int, struct sshbuf *); 137 int mm_answer_pam_account(struct ssh *, int, struct sshbuf *); 138 int mm_answer_pam_init_ctx(struct ssh *, int, struct sshbuf *); 139 int mm_answer_pam_query(struct ssh *, int, struct sshbuf *); 140 int mm_answer_pam_respond(struct ssh *, int, struct sshbuf *); 141 int mm_answer_pam_free_ctx(struct ssh *, int, struct sshbuf *); 142 #endif 143 144 #ifdef GSSAPI 145 int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *); 146 int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *); 147 int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *); 148 int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *); 149 #endif 150 151 #ifdef SSH_AUDIT_EVENTS 152 int mm_answer_audit_event(struct ssh *, int, struct sshbuf *); 153 int mm_answer_audit_command(struct ssh *, int, struct sshbuf *); 154 #endif 155 156 static Authctxt *authctxt; 157 158 /* local state for key verify */ 159 static u_char *key_blob = NULL; 160 static size_t key_bloblen = 0; 161 static u_int key_blobtype = MM_NOKEY; 162 static struct sshauthopt *key_opts = NULL; 163 static char *hostbased_cuser = NULL; 164 static char *hostbased_chost = NULL; 165 static char *auth_method = "unknown"; 166 static char *auth_submethod = NULL; 167 static u_int session_id2_len = 0; 168 static u_char *session_id2 = NULL; 169 static pid_t monitor_child_pid; 170 int auth_attempted = 0; 171 172 struct mon_table { 173 enum monitor_reqtype type; 174 int flags; 175 int (*f)(struct ssh *, int, struct sshbuf *); 176 }; 177 178 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 179 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 180 #define MON_ONCE 0x0010 /* Disable after calling */ 181 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 182 183 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 184 185 #define MON_PERMIT 0x1000 /* Request is permitted */ 186 187 static int monitor_read(struct ssh *, struct monitor *, struct mon_table *, 188 struct mon_table **); 189 static int monitor_read_log(struct monitor *); 190 191 struct mon_table mon_dispatch_proto20[] = { 192 {MONITOR_REQ_STATE, MON_ONCE, mm_answer_state}, 193 #ifdef WITH_OPENSSL 194 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 195 #endif 196 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 197 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 198 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 199 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 200 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 201 #ifdef USE_PAM 202 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 203 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 204 {MONITOR_REQ_PAM_INIT_CTX, MON_ONCE, mm_answer_pam_init_ctx}, 205 {MONITOR_REQ_PAM_QUERY, 0, mm_answer_pam_query}, 206 {MONITOR_REQ_PAM_RESPOND, MON_ONCE, mm_answer_pam_respond}, 207 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 208 #endif 209 #ifdef SSH_AUDIT_EVENTS 210 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 211 #endif 212 #ifdef BSD_AUTH 213 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 214 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 215 #endif 216 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 217 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 218 #ifdef GSSAPI 219 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 220 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx}, 221 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok}, 222 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic}, 223 #endif 224 {0, 0, NULL} 225 }; 226 227 struct mon_table mon_dispatch_postauth20[] = { 228 {MONITOR_REQ_STATE, MON_ONCE, mm_answer_state}, 229 #ifdef WITH_OPENSSL 230 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 231 #endif 232 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 233 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 234 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 235 {MONITOR_REQ_TERM, 0, mm_answer_term}, 236 #ifdef SSH_AUDIT_EVENTS 237 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 238 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command}, 239 #endif 240 {0, 0, NULL} 241 }; 242 243 struct mon_table *mon_dispatch; 244 245 /* Specifies if a certain message is allowed at the moment */ 246 static void 247 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 248 { 249 while (ent->f != NULL) { 250 if (ent->type == type) { 251 ent->flags &= ~MON_PERMIT; 252 ent->flags |= permit ? MON_PERMIT : 0; 253 return; 254 } 255 ent++; 256 } 257 } 258 259 static void 260 monitor_permit_authentications(int permit) 261 { 262 struct mon_table *ent = mon_dispatch; 263 264 while (ent->f != NULL) { 265 if (ent->flags & MON_AUTH) { 266 ent->flags &= ~MON_PERMIT; 267 ent->flags |= permit ? MON_PERMIT : 0; 268 } 269 ent++; 270 } 271 } 272 273 void 274 monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor) 275 { 276 struct mon_table *ent; 277 int authenticated = 0, partial = 0; 278 279 debug3("preauth child monitor started"); 280 281 if (pmonitor->m_recvfd >= 0) 282 close(pmonitor->m_recvfd); 283 if (pmonitor->m_log_sendfd >= 0) 284 close(pmonitor->m_log_sendfd); 285 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 286 287 authctxt = (Authctxt *)ssh->authctxt; 288 memset(authctxt, 0, sizeof(*authctxt)); 289 ssh->authctxt = authctxt; 290 291 authctxt->loginmsg = loginmsg; 292 293 mon_dispatch = mon_dispatch_proto20; 294 /* Permit requests for state, moduli and signatures */ 295 monitor_permit(mon_dispatch, MONITOR_REQ_STATE, 1); 296 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 297 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 298 299 /* The first few requests do not require asynchronous access */ 300 while (!authenticated) { 301 partial = 0; 302 auth_method = "unknown"; 303 auth_submethod = NULL; 304 auth2_authctxt_reset_info(authctxt); 305 306 authenticated = (monitor_read(ssh, pmonitor, 307 mon_dispatch, &ent) == 1); 308 309 /* Record that auth was attempted to set exit status later */ 310 if ((ent->flags & MON_AUTH) != 0) 311 auth_attempted = 1; 312 313 /* Special handling for multiple required authentications */ 314 if (options.num_auth_methods != 0) { 315 if (authenticated && 316 !auth2_update_methods_lists(authctxt, 317 auth_method, auth_submethod)) { 318 debug3_f("method %s: partial", auth_method); 319 authenticated = 0; 320 partial = 1; 321 } 322 } 323 324 if (authenticated) { 325 if (!(ent->flags & MON_AUTHDECIDE)) 326 fatal_f("unexpected authentication from %d", 327 ent->type); 328 if (authctxt->pw->pw_uid == 0 && 329 !auth_root_allowed(ssh, 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 struct sshbuf *m; 335 336 if ((m = sshbuf_new()) == NULL) 337 fatal("%s: sshbuf_new failed", 338 __func__); 339 mm_request_receive_expect(pmonitor->m_sendfd, 340 MONITOR_REQ_PAM_ACCOUNT, m); 341 authenticated = mm_answer_pam_account( 342 ssh, pmonitor->m_sendfd, m); 343 sshbuf_free(m); 344 } 345 #endif 346 } 347 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 348 auth_log(ssh, authenticated, partial, 349 auth_method, auth_submethod); 350 if (!partial && !authenticated) 351 authctxt->failures++; 352 if (authenticated || partial) { 353 auth2_update_session_info(authctxt, 354 auth_method, auth_submethod); 355 } 356 } 357 if (authctxt->failures > options.max_authtries) { 358 BLACKLIST_NOTIFY(ssh, BLACKLIST_AUTH_FAIL, 359 "Too many authentication attempts"); 360 /* Shouldn't happen */ 361 fatal_f("privsep child made too many authentication " 362 "attempts"); 363 } 364 } 365 366 if (!authctxt->valid) { 367 BLACKLIST_NOTIFY(ssh, BLACKLIST_AUTH_FAIL, 368 "Authenticated invalid user"); 369 fatal_f("authenticated invalid user"); 370 } 371 if (strcmp(auth_method, "unknown") == 0) { 372 BLACKLIST_NOTIFY(ssh, BLACKLIST_AUTH_FAIL, 373 "Authentication method name unknown"); 374 fatal_f("authentication method name unknown"); 375 } 376 377 debug_f("user %s authenticated by privileged process", authctxt->user); 378 auth_attempted = 0; 379 ssh->authctxt = NULL; 380 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 381 382 mm_get_keystate(ssh, pmonitor); 383 384 /* Drain any buffered messages from the child */ 385 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 386 ; 387 388 if (pmonitor->m_recvfd >= 0) 389 close(pmonitor->m_recvfd); 390 if (pmonitor->m_log_sendfd >= 0) 391 close(pmonitor->m_log_sendfd); 392 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 393 } 394 395 static void 396 monitor_set_child_handler(pid_t pid) 397 { 398 monitor_child_pid = pid; 399 } 400 401 static void 402 monitor_child_handler(int sig) 403 { 404 kill(monitor_child_pid, sig); 405 } 406 407 void 408 monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor) 409 { 410 close(pmonitor->m_recvfd); 411 pmonitor->m_recvfd = -1; 412 413 monitor_set_child_handler(pmonitor->m_pid); 414 ssh_signal(SIGHUP, &monitor_child_handler); 415 ssh_signal(SIGTERM, &monitor_child_handler); 416 ssh_signal(SIGINT, &monitor_child_handler); 417 #ifdef SIGXFSZ 418 ssh_signal(SIGXFSZ, SIG_IGN); 419 #endif 420 421 mon_dispatch = mon_dispatch_postauth20; 422 423 /* Permit requests for moduli and signatures */ 424 monitor_permit(mon_dispatch, MONITOR_REQ_STATE, 1); 425 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 426 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 427 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 428 429 if (auth_opts->permit_pty_flag) { 430 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 431 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 432 } 433 434 for (;;) 435 monitor_read(ssh, pmonitor, mon_dispatch, NULL); 436 } 437 438 static int 439 monitor_read_log(struct monitor *pmonitor) 440 { 441 struct sshbuf *logmsg; 442 u_int len, level, forced; 443 char *msg; 444 u_char *p; 445 int r; 446 447 if ((logmsg = sshbuf_new()) == NULL) 448 fatal_f("sshbuf_new"); 449 450 /* Read length */ 451 if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0) 452 fatal_fr(r, "reserve len"); 453 if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) { 454 if (errno == EPIPE) { 455 sshbuf_free(logmsg); 456 debug_f("child log fd closed"); 457 close(pmonitor->m_log_recvfd); 458 pmonitor->m_log_recvfd = -1; 459 return -1; 460 } 461 fatal_f("log fd read: %s", strerror(errno)); 462 } 463 if ((r = sshbuf_get_u32(logmsg, &len)) != 0) 464 fatal_fr(r, "parse len"); 465 if (len <= 4 || len > 8192) 466 fatal_f("invalid log message length %u", len); 467 468 /* Read severity, message */ 469 sshbuf_reset(logmsg); 470 if ((r = sshbuf_reserve(logmsg, len, &p)) != 0) 471 fatal_fr(r, "reserve msg"); 472 if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len) 473 fatal_f("log fd read: %s", strerror(errno)); 474 if ((r = sshbuf_get_u32(logmsg, &level)) != 0 || 475 (r = sshbuf_get_u32(logmsg, &forced)) != 0 || 476 (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0) 477 fatal_fr(r, "parse"); 478 479 /* Log it */ 480 if (log_level_name(level) == NULL) 481 fatal_f("invalid log level %u (corrupted message?)", level); 482 sshlogdirect(level, forced, "%s [%s]", msg, 483 mon_dispatch == mon_dispatch_postauth20 ? "postauth" : "preauth"); 484 485 sshbuf_free(logmsg); 486 free(msg); 487 488 return 0; 489 } 490 491 static int 492 monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent, 493 struct mon_table **pent) 494 { 495 struct sshbuf *m; 496 int r, ret; 497 u_char type; 498 struct pollfd pfd[2]; 499 500 for (;;) { 501 memset(&pfd, 0, sizeof(pfd)); 502 pfd[0].fd = pmonitor->m_sendfd; 503 pfd[0].events = POLLIN; 504 pfd[1].fd = pmonitor->m_log_recvfd; 505 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 506 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 507 if (errno == EINTR || errno == EAGAIN) 508 continue; 509 fatal_f("poll: %s", strerror(errno)); 510 } 511 if (pfd[1].revents) { 512 /* 513 * Drain all log messages before processing next 514 * monitor request. 515 */ 516 monitor_read_log(pmonitor); 517 continue; 518 } 519 if (pfd[0].revents) 520 break; /* Continues below */ 521 } 522 523 if ((m = sshbuf_new()) == NULL) 524 fatal_f("sshbuf_new"); 525 526 mm_request_receive(pmonitor->m_sendfd, m); 527 if ((r = sshbuf_get_u8(m, &type)) != 0) 528 fatal_fr(r, "parse type"); 529 530 debug3_f("checking request %d", type); 531 532 while (ent->f != NULL) { 533 if (ent->type == type) 534 break; 535 ent++; 536 } 537 538 if (ent->f != NULL) { 539 if (!(ent->flags & MON_PERMIT)) 540 fatal_f("unpermitted request %d", type); 541 ret = (*ent->f)(ssh, pmonitor->m_sendfd, m); 542 sshbuf_free(m); 543 544 /* The child may use this request only once, disable it */ 545 if (ent->flags & MON_ONCE) { 546 debug2_f("%d used once, disabling now", type); 547 ent->flags &= ~MON_PERMIT; 548 } 549 550 if (pent != NULL) 551 *pent = ent; 552 553 return ret; 554 } 555 556 fatal_f("unsupported request: %d", type); 557 558 /* NOTREACHED */ 559 return (-1); 560 } 561 562 /* allowed key state */ 563 static int 564 monitor_allowed_key(const u_char *blob, u_int bloblen) 565 { 566 /* make sure key is allowed */ 567 if (key_blob == NULL || key_bloblen != bloblen || 568 timingsafe_bcmp(key_blob, blob, key_bloblen)) 569 return (0); 570 return (1); 571 } 572 573 static void 574 monitor_reset_key_state(void) 575 { 576 /* reset state */ 577 free(key_blob); 578 free(hostbased_cuser); 579 free(hostbased_chost); 580 sshauthopt_free(key_opts); 581 key_blob = NULL; 582 key_bloblen = 0; 583 key_blobtype = MM_NOKEY; 584 key_opts = NULL; 585 hostbased_cuser = NULL; 586 hostbased_chost = NULL; 587 } 588 589 int 590 mm_answer_state(struct ssh *ssh, int sock, struct sshbuf *m) 591 { 592 struct sshbuf *inc = NULL, *hostkeys = NULL; 593 struct sshbuf *opts = NULL, *confdata = NULL; 594 struct include_item *item = NULL; 595 int postauth; 596 int r; 597 598 sshbuf_reset(m); 599 600 debug_f("config len %zu", sshbuf_len(cfg)); 601 602 if ((m = sshbuf_new()) == NULL || 603 (inc = sshbuf_new()) == NULL || 604 (opts = sshbuf_new()) == NULL || 605 (confdata = sshbuf_new()) == NULL) 606 fatal_f("sshbuf_new failed"); 607 608 /* XXX unnecessary? */ 609 /* pack includes into a string */ 610 TAILQ_FOREACH(item, &includes, entry) { 611 if ((r = sshbuf_put_cstring(inc, item->selector)) != 0 || 612 (r = sshbuf_put_cstring(inc, item->filename)) != 0 || 613 (r = sshbuf_put_stringb(inc, item->contents)) != 0) 614 fatal_fr(r, "compose includes"); 615 } 616 617 hostkeys = pack_hostkeys(); 618 619 /* 620 * Protocol from monitor to unpriv privsep process: 621 * string configuration 622 * uint64 timing_secret XXX move delays to monitor and remove 623 * string host_keys[] { 624 * string public_key 625 * string certificate 626 * } 627 * string server_banner 628 * string client_banner 629 * string included_files[] { 630 * string selector 631 * string filename 632 * string contents 633 * } 634 * string configuration_data (postauth) 635 * string keystate (postauth) 636 * string authenticated_user (postauth) 637 * string session_info (postauth) 638 * string authopts (postauth) 639 */ 640 if ((r = sshbuf_put_stringb(m, cfg)) != 0 || 641 (r = sshbuf_put_u64(m, options.timing_secret)) != 0 || 642 (r = sshbuf_put_stringb(m, hostkeys)) != 0 || 643 (r = sshbuf_put_stringb(m, ssh->kex->server_version)) != 0 || 644 (r = sshbuf_put_stringb(m, ssh->kex->client_version)) != 0 || 645 (r = sshbuf_put_stringb(m, inc)) != 0) 646 fatal_fr(r, "compose config"); 647 648 postauth = (authctxt && authctxt->pw && authctxt->authenticated); 649 if (postauth) { 650 /* XXX shouldn't be reachable */ 651 fatal_f("internal error: called in postauth"); 652 } 653 654 sshbuf_free(inc); 655 sshbuf_free(opts); 656 sshbuf_free(confdata); 657 658 mm_request_send(sock, MONITOR_ANS_STATE, m); 659 660 debug3_f("done"); 661 662 return (0); 663 } 664 665 #ifdef WITH_OPENSSL 666 int 667 mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m) 668 { 669 DH *dh; 670 const BIGNUM *dh_p, *dh_g; 671 int r; 672 u_int min, want, max; 673 674 if ((r = sshbuf_get_u32(m, &min)) != 0 || 675 (r = sshbuf_get_u32(m, &want)) != 0 || 676 (r = sshbuf_get_u32(m, &max)) != 0) 677 fatal_fr(r, "parse"); 678 679 debug3_f("got parameters: %d %d %d", min, want, max); 680 /* We need to check here, too, in case the child got corrupted */ 681 if (max < min || want < min || max < want) 682 fatal_f("bad parameters: %d %d %d", min, want, max); 683 684 sshbuf_reset(m); 685 686 dh = choose_dh(min, want, max); 687 if (dh == NULL) { 688 if ((r = sshbuf_put_u8(m, 0)) != 0) 689 fatal_fr(r, "assemble empty"); 690 return (0); 691 } else { 692 /* Send first bignum */ 693 DH_get0_pqg(dh, &dh_p, NULL, &dh_g); 694 if ((r = sshbuf_put_u8(m, 1)) != 0 || 695 (r = sshbuf_put_bignum2(m, dh_p)) != 0 || 696 (r = sshbuf_put_bignum2(m, dh_g)) != 0) 697 fatal_fr(r, "assemble"); 698 699 DH_free(dh); 700 } 701 mm_request_send(sock, MONITOR_ANS_MODULI, m); 702 return (0); 703 } 704 #endif 705 706 int 707 mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m) 708 { 709 extern int auth_sock; /* XXX move to state struct? */ 710 struct sshkey *pubkey, *key; 711 struct sshbuf *sigbuf = NULL; 712 u_char *p = NULL, *signature = NULL; 713 char *alg = NULL; 714 size_t datlen, siglen; 715 int r, is_proof = 0, keyid; 716 u_int compat; 717 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 718 719 debug3_f("entering"); 720 721 if ((r = sshkey_froms(m, &pubkey)) != 0 || 722 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 723 (r = sshbuf_get_cstring(m, &alg, NULL)) != 0 || 724 (r = sshbuf_get_u32(m, &compat)) != 0) 725 fatal_fr(r, "parse"); 726 727 if ((keyid = get_hostkey_index(pubkey, 1, ssh)) == -1) 728 fatal_f("unknown hostkey"); 729 debug_f("hostkey %s index %d", sshkey_ssh_name(pubkey), keyid); 730 sshkey_free(pubkey); 731 732 /* 733 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 734 * SHA384 (48 bytes) and SHA512 (64 bytes). 735 * 736 * Otherwise, verify the signature request is for a hostkey 737 * proof. 738 * 739 * XXX perform similar check for KEX signature requests too? 740 * it's not trivial, since what is signed is the hash, rather 741 * than the full kex structure... 742 */ 743 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 744 /* 745 * Construct expected hostkey proof and compare it to what 746 * the client sent us. 747 */ 748 if (session_id2_len == 0) /* hostkeys is never first */ 749 fatal_f("bad data length: %zu", datlen); 750 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 751 fatal_f("no hostkey for index %d", keyid); 752 if ((sigbuf = sshbuf_new()) == NULL) 753 fatal_f("sshbuf_new"); 754 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 755 (r = sshbuf_put_string(sigbuf, session_id2, 756 session_id2_len)) != 0 || 757 (r = sshkey_puts(key, sigbuf)) != 0) 758 fatal_fr(r, "assemble private key proof"); 759 if (datlen != sshbuf_len(sigbuf) || 760 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 761 fatal_f("bad data length: %zu, hostkey proof len %zu", 762 datlen, sshbuf_len(sigbuf)); 763 sshbuf_free(sigbuf); 764 is_proof = 1; 765 } 766 767 /* save session id, it will be passed on the first call */ 768 if (session_id2_len == 0) { 769 session_id2_len = datlen; 770 session_id2 = xmalloc(session_id2_len); 771 memcpy(session_id2, p, session_id2_len); 772 } 773 774 if ((key = get_hostkey_by_index(keyid)) != NULL) { 775 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 776 options.sk_provider, NULL, compat)) != 0) 777 fatal_fr(r, "sign"); 778 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 779 auth_sock > 0) { 780 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 781 p, datlen, alg, compat)) != 0) 782 fatal_fr(r, "agent sign"); 783 } else 784 fatal_f("no hostkey from index %d", keyid); 785 786 debug3_f("%s %s signature len=%zu", alg, 787 is_proof ? "hostkey proof" : "KEX", siglen); 788 789 sshbuf_reset(m); 790 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 791 fatal_fr(r, "assemble"); 792 793 free(alg); 794 free(p); 795 free(signature); 796 797 mm_request_send(sock, MONITOR_ANS_SIGN, m); 798 799 /* Turn on permissions for getpwnam */ 800 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 801 802 return (0); 803 } 804 805 #define PUTPW(b, id) \ 806 do { \ 807 if ((r = sshbuf_put_string(b, \ 808 &pwent->id, sizeof(pwent->id))) != 0) \ 809 fatal_fr(r, "assemble %s", #id); \ 810 } while (0) 811 812 void 813 mm_encode_server_options(struct sshbuf *m) 814 { 815 int r; 816 u_int i; 817 818 /* XXX this leaks raw pointers to the unpriv child processes */ 819 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0) 820 fatal_fr(r, "assemble options"); 821 822 #define M_CP_STROPT(x) do { \ 823 if (options.x != NULL && \ 824 (r = sshbuf_put_cstring(m, options.x)) != 0) \ 825 fatal_fr(r, "assemble %s", #x); \ 826 } while (0) 827 #define M_CP_STRARRAYOPT(x, nx) do { \ 828 for (i = 0; i < options.nx; i++) { \ 829 if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \ 830 fatal_fr(r, "assemble %s", #x); \ 831 } \ 832 } while (0) 833 /* See comment in servconf.h */ 834 COPY_MATCH_STRING_OPTS(); 835 #undef M_CP_STROPT 836 #undef M_CP_STRARRAYOPT 837 } 838 839 /* Retrieves the password entry and also checks if the user is permitted */ 840 int 841 mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m) 842 { 843 struct passwd *pwent; 844 int r, allowed = 0; 845 846 debug3_f("entering"); 847 848 if (authctxt->attempt++ != 0) 849 fatal_f("multiple attempts for getpwnam"); 850 851 if ((r = sshbuf_get_cstring(m, &authctxt->user, NULL)) != 0) 852 fatal_fr(r, "parse"); 853 854 pwent = getpwnamallow(ssh, authctxt->user); 855 856 setproctitle("%s [priv]", pwent ? authctxt->user : "unknown"); 857 858 sshbuf_reset(m); 859 860 if (pwent == NULL) { 861 if ((r = sshbuf_put_u8(m, 0)) != 0) 862 fatal_fr(r, "assemble fakepw"); 863 authctxt->pw = fakepw(); 864 goto out; 865 } 866 867 allowed = 1; 868 authctxt->pw = pwent; 869 authctxt->valid = 1; 870 871 /* XXX send fake class/dir/shell, etc. */ 872 if ((r = sshbuf_put_u8(m, 1)) != 0) 873 fatal_fr(r, "assemble ok"); 874 PUTPW(m, pw_uid); 875 PUTPW(m, pw_gid); 876 #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE 877 PUTPW(m, pw_change); 878 #endif 879 #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE 880 PUTPW(m, pw_expire); 881 #endif 882 if ((r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || 883 (r = sshbuf_put_cstring(m, "*")) != 0 || 884 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS 885 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 || 886 #endif 887 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS 888 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 || 889 #endif 890 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 || 891 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0) 892 fatal_fr(r, "assemble pw"); 893 894 out: 895 ssh_packet_set_log_preamble(ssh, "%suser %s", 896 authctxt->valid ? "authenticating" : "invalid ", authctxt->user); 897 898 if (options.refuse_connection) { 899 logit("administratively prohibited connection for " 900 "%s%s from %.128s port %d", 901 authctxt->valid ? "" : "invalid user ", 902 authctxt->user, ssh_remote_ipaddr(ssh), 903 ssh_remote_port(ssh)); 904 cleanup_exit(EXIT_CONFIG_REFUSED); 905 } 906 907 /* Send active options to unpriv */ 908 mm_encode_server_options(m); 909 910 /* Create valid auth method lists */ 911 if (auth2_setup_methods_lists(authctxt) != 0) { 912 /* 913 * The monitor will continue long enough to let the child 914 * run to its packet_disconnect(), but it must not allow any 915 * authentication to succeed. 916 */ 917 debug_f("no valid authentication method lists"); 918 } 919 920 debug3_f("sending MONITOR_ANS_PWNAM: %d", allowed); 921 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 922 923 /* Allow service/style information on the auth context */ 924 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 925 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 926 927 #ifdef USE_PAM 928 if (options.use_pam) 929 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); 930 #endif 931 932 return (0); 933 } 934 935 int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m) 936 { 937 char *banner; 938 int r; 939 940 sshbuf_reset(m); 941 banner = auth2_read_banner(); 942 if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0) 943 fatal_fr(r, "assemble"); 944 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 945 free(banner); 946 947 return (0); 948 } 949 950 int 951 mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m) 952 { 953 int r; 954 955 monitor_permit_authentications(1); 956 957 if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 || 958 (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0) 959 fatal_fr(r, "parse"); 960 debug3_f("service=%s, style=%s", authctxt->service, authctxt->style); 961 962 if (strlen(authctxt->style) == 0) { 963 free(authctxt->style); 964 authctxt->style = NULL; 965 } 966 967 return (0); 968 } 969 970 /* 971 * Check that the key type appears in the supplied pattern list, ignoring 972 * mismatches in the signature algorithm. (Signature algorithm checks are 973 * performed in the unprivileged authentication code). 974 * Returns 1 on success, 0 otherwise. 975 */ 976 static int 977 key_base_type_match(const char *method, const struct sshkey *key, 978 const char *list) 979 { 980 char *s, *l, *ol = xstrdup(list); 981 int found = 0; 982 983 l = ol; 984 for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) { 985 if (sshkey_type_from_name(s) == key->type) { 986 found = 1; 987 break; 988 } 989 } 990 if (!found) { 991 error("%s key type %s is not in permitted list %s", method, 992 sshkey_ssh_name(key), list); 993 } 994 995 free(ol); 996 return found; 997 } 998 999 int 1000 mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m) 1001 { 1002 static int call_count; 1003 char *passwd; 1004 int r, authenticated; 1005 size_t plen; 1006 1007 if (!options.password_authentication) 1008 fatal_f("password authentication not enabled"); 1009 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0) 1010 fatal_fr(r, "parse"); 1011 /* Only authenticate if the context is valid */ 1012 authenticated = options.password_authentication && 1013 auth_password(ssh, passwd); 1014 freezero(passwd, plen); 1015 1016 sshbuf_reset(m); 1017 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 1018 fatal_fr(r, "assemble"); 1019 #ifdef USE_PAM 1020 if ((r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0) 1021 fatal_fr(r, "assemble PAM"); 1022 #endif 1023 1024 debug3("%s: sending result %d", __func__, authenticated); 1025 debug3_f("sending result %d", authenticated); 1026 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 1027 1028 call_count++; 1029 if (plen == 0 && call_count == 1) 1030 auth_method = "none"; 1031 else 1032 auth_method = "password"; 1033 1034 /* Causes monitor loop to terminate if authenticated */ 1035 return (authenticated); 1036 } 1037 1038 #ifdef BSD_AUTH 1039 int 1040 mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m) 1041 { 1042 char *name, *infotxt; 1043 u_int numprompts, *echo_on, success; 1044 char **prompts; 1045 int r; 1046 1047 if (!options.kbd_interactive_authentication) 1048 fatal_f("kbd-int authentication not enabled"); 1049 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 1050 &prompts, &echo_on) < 0 ? 0 : 1; 1051 1052 sshbuf_reset(m); 1053 if ((r = sshbuf_put_u32(m, success)) != 0) 1054 fatal_fr(r, "assemble"); 1055 if (success) { 1056 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0) 1057 fatal_fr(r, "assemble prompt"); 1058 } 1059 1060 debug3_f("sending challenge success: %u", success); 1061 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 1062 1063 if (success) { 1064 free(name); 1065 free(infotxt); 1066 free(prompts); 1067 free(echo_on); 1068 } 1069 1070 return (0); 1071 } 1072 1073 int 1074 mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m) 1075 { 1076 char *response; 1077 int r, authok; 1078 1079 if (!options.kbd_interactive_authentication) 1080 fatal_f("kbd-int authentication not enabled"); 1081 if (authctxt->as == NULL) 1082 fatal_f("no bsd auth session"); 1083 1084 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 1085 fatal_fr(r, "parse"); 1086 authok = options.kbd_interactive_authentication && 1087 auth_userresponse(authctxt->as, response, 0); 1088 authctxt->as = NULL; 1089 debug3_f("<%s> = <%d>", response, authok); 1090 free(response); 1091 1092 sshbuf_reset(m); 1093 if ((r = sshbuf_put_u32(m, authok)) != 0) 1094 fatal_fr(r, "assemble"); 1095 1096 debug3_f("sending authenticated: %d", authok); 1097 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 1098 1099 auth_method = "keyboard-interactive"; 1100 auth_submethod = "bsdauth"; 1101 1102 return (authok != 0); 1103 } 1104 #endif 1105 1106 #ifdef USE_PAM 1107 int 1108 mm_answer_pam_start(struct ssh *ssh, int sock, struct sshbuf *m) 1109 { 1110 if (!options.use_pam) 1111 fatal("UsePAM not set, but ended up in %s anyway", __func__); 1112 1113 start_pam(ssh); 1114 1115 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); 1116 if (options.kbd_interactive_authentication) 1117 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 1118 1119 return (0); 1120 } 1121 1122 int 1123 mm_answer_pam_account(struct ssh *ssh, int sock, struct sshbuf *m) 1124 { 1125 u_int ret; 1126 int r; 1127 1128 if (!options.use_pam) 1129 fatal("%s: PAM not enabled", __func__); 1130 1131 ret = do_pam_account(); 1132 1133 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1134 (r = sshbuf_put_stringb(m, loginmsg)) != 0) 1135 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1136 1137 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m); 1138 1139 return (ret); 1140 } 1141 1142 static void *sshpam_ctxt, *sshpam_authok; 1143 extern KbdintDevice sshpam_device; 1144 1145 int 1146 mm_answer_pam_init_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1147 { 1148 u_int ok = 0; 1149 int r; 1150 1151 debug3("%s", __func__); 1152 if (!options.kbd_interactive_authentication) 1153 fatal("%s: kbd-int authentication not enabled", __func__); 1154 if (sshpam_ctxt != NULL) 1155 fatal("%s: already called", __func__); 1156 sshpam_ctxt = (sshpam_device.init_ctx)(authctxt); 1157 sshpam_authok = NULL; 1158 sshbuf_reset(m); 1159 if (sshpam_ctxt != NULL) { 1160 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 1161 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_QUERY, 1); 1162 ok = 1; 1163 } 1164 if ((r = sshbuf_put_u32(m, ok)) != 0) 1165 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1166 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); 1167 return (0); 1168 } 1169 1170 int 1171 mm_answer_pam_query(struct ssh *ssh, int sock, struct sshbuf *m) 1172 { 1173 char *name = NULL, *info = NULL, **prompts = NULL; 1174 u_int i, num = 0, *echo_on = 0; 1175 int r, ret; 1176 1177 debug3("%s", __func__); 1178 sshpam_authok = NULL; 1179 if (sshpam_ctxt == NULL) 1180 fatal("%s: no context", __func__); 1181 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, 1182 &num, &prompts, &echo_on); 1183 if (ret == 0 && num == 0) 1184 sshpam_authok = sshpam_ctxt; 1185 if (num > 1 || name == NULL || info == NULL) 1186 fatal("sshpam_device.query failed"); 1187 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_RESPOND, 1); 1188 sshbuf_reset(m); 1189 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1190 (r = sshbuf_put_cstring(m, name)) != 0 || 1191 (r = sshbuf_put_cstring(m, info)) != 0 || 1192 (r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0 || 1193 (r = sshbuf_put_u32(m, num)) != 0) 1194 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1195 free(name); 1196 free(info); 1197 for (i = 0; i < num; ++i) { 1198 if ((r = sshbuf_put_cstring(m, prompts[i])) != 0 || 1199 (r = sshbuf_put_u32(m, echo_on[i])) != 0) 1200 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1201 free(prompts[i]); 1202 } 1203 free(prompts); 1204 free(echo_on); 1205 auth_method = "keyboard-interactive"; 1206 auth_submethod = "pam"; 1207 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m); 1208 return (0); 1209 } 1210 1211 int 1212 mm_answer_pam_respond(struct ssh *ssh, int sock, struct sshbuf *m) 1213 { 1214 char **resp; 1215 u_int i, num; 1216 int r, ret; 1217 1218 debug3("%s", __func__); 1219 if (sshpam_ctxt == NULL) 1220 fatal("%s: no context", __func__); 1221 sshpam_authok = NULL; 1222 if ((r = sshbuf_get_u32(m, &num)) != 0) 1223 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1224 if (num > PAM_MAX_NUM_MSG) { 1225 fatal_f("Too many PAM messages, got %u, expected <= %u", 1226 num, (unsigned)PAM_MAX_NUM_MSG); 1227 } 1228 if (num > 0) { 1229 resp = xcalloc(num, sizeof(char *)); 1230 for (i = 0; i < num; ++i) { 1231 if ((r = sshbuf_get_cstring(m, &(resp[i]), NULL)) != 0) 1232 fatal("%s: buffer error: %s", 1233 __func__, ssh_err(r)); 1234 } 1235 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp); 1236 for (i = 0; i < num; ++i) 1237 free(resp[i]); 1238 free(resp); 1239 } else { 1240 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL); 1241 } 1242 sshbuf_reset(m); 1243 if ((r = sshbuf_put_u32(m, ret)) != 0) 1244 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1245 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m); 1246 auth_method = "keyboard-interactive"; 1247 auth_submethod = "pam"; 1248 if (ret == 0) 1249 sshpam_authok = sshpam_ctxt; 1250 return (0); 1251 } 1252 1253 int 1254 mm_answer_pam_free_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1255 { 1256 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt; 1257 1258 debug3("%s", __func__); 1259 if (sshpam_ctxt == NULL) 1260 fatal("%s: no context", __func__); 1261 (sshpam_device.free_ctx)(sshpam_ctxt); 1262 sshpam_ctxt = sshpam_authok = NULL; 1263 sshbuf_reset(m); 1264 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); 1265 /* Allow another attempt */ 1266 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 1267 auth_method = "keyboard-interactive"; 1268 auth_submethod = "pam"; 1269 return r; 1270 } 1271 #endif 1272 1273 int 1274 mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m) 1275 { 1276 struct sshkey *key = NULL; 1277 char *cuser, *chost; 1278 u_int pubkey_auth_attempt; 1279 u_int type = 0; 1280 int r, allowed = 0; 1281 struct sshauthopt *opts = NULL; 1282 1283 debug3_f("entering"); 1284 if ((r = sshbuf_get_u32(m, &type)) != 0 || 1285 (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 || 1286 (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 || 1287 (r = sshkey_froms(m, &key)) != 0 || 1288 (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0) 1289 fatal_fr(r, "parse"); 1290 1291 if (key != NULL && authctxt->valid) { 1292 switch (type) { 1293 case MM_USERKEY: 1294 auth_method = "publickey"; 1295 if (!options.pubkey_authentication) 1296 break; 1297 if (auth2_key_already_used(authctxt, key)) 1298 break; 1299 if (!key_base_type_match(auth_method, key, 1300 options.pubkey_accepted_algos)) 1301 break; 1302 allowed = user_key_allowed(ssh, authctxt->pw, key, 1303 pubkey_auth_attempt, &opts); 1304 break; 1305 case MM_HOSTKEY: 1306 auth_method = "hostbased"; 1307 if (!options.hostbased_authentication) 1308 break; 1309 if (auth2_key_already_used(authctxt, key)) 1310 break; 1311 if (!key_base_type_match(auth_method, key, 1312 options.hostbased_accepted_algos)) 1313 break; 1314 allowed = hostbased_key_allowed(ssh, authctxt->pw, 1315 cuser, chost, key); 1316 auth2_record_info(authctxt, 1317 "client user \"%.100s\", client host \"%.100s\"", 1318 cuser, chost); 1319 break; 1320 default: 1321 fatal_f("unknown key type %u", type); 1322 break; 1323 } 1324 } 1325 1326 debug3_f("%s authentication%s: %s key is %s", auth_method, 1327 pubkey_auth_attempt ? "" : " test", 1328 (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key), 1329 allowed ? "allowed" : "not allowed"); 1330 1331 auth2_record_key(authctxt, 0, key); 1332 1333 /* clear temporarily storage (used by verify) */ 1334 monitor_reset_key_state(); 1335 1336 if (allowed) { 1337 /* Save temporarily for comparison in verify */ 1338 if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0) 1339 fatal_fr(r, "sshkey_to_blob"); 1340 key_blobtype = type; 1341 key_opts = opts; 1342 hostbased_cuser = cuser; 1343 hostbased_chost = chost; 1344 } else { 1345 /* Log failed attempt */ 1346 auth_log(ssh, 0, 0, auth_method, NULL); 1347 free(cuser); 1348 free(chost); 1349 } 1350 sshkey_free(key); 1351 1352 sshbuf_reset(m); 1353 if ((r = sshbuf_put_u32(m, allowed)) != 0) 1354 fatal_fr(r, "assemble"); 1355 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0) 1356 fatal_fr(r, "sshauthopt_serialise"); 1357 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 1358 1359 if (!allowed) 1360 sshauthopt_free(opts); 1361 1362 return (0); 1363 } 1364 1365 static int 1366 monitor_valid_userblob(struct ssh *ssh, const u_char *data, u_int datalen) 1367 { 1368 struct sshbuf *b; 1369 struct sshkey *hostkey = NULL; 1370 const u_char *p; 1371 char *userstyle, *cp; 1372 size_t len; 1373 u_char type; 1374 int hostbound = 0, r, fail = 0; 1375 1376 if ((b = sshbuf_from(data, datalen)) == NULL) 1377 fatal_f("sshbuf_from"); 1378 1379 if (ssh->compat & SSH_OLD_SESSIONID) { 1380 p = sshbuf_ptr(b); 1381 len = sshbuf_len(b); 1382 if ((session_id2 == NULL) || 1383 (len < session_id2_len) || 1384 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1385 fail++; 1386 if ((r = sshbuf_consume(b, session_id2_len)) != 0) 1387 fatal_fr(r, "consume"); 1388 } else { 1389 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1390 fatal_fr(r, "parse sessionid"); 1391 if ((session_id2 == NULL) || 1392 (len != session_id2_len) || 1393 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1394 fail++; 1395 } 1396 if ((r = sshbuf_get_u8(b, &type)) != 0) 1397 fatal_fr(r, "parse type"); 1398 if (type != SSH2_MSG_USERAUTH_REQUEST) 1399 fail++; 1400 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1401 fatal_fr(r, "parse userstyle"); 1402 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1403 authctxt->style ? ":" : "", 1404 authctxt->style ? authctxt->style : ""); 1405 if (strcmp(userstyle, cp) != 0) { 1406 logit("wrong user name passed to monitor: " 1407 "expected %s != %.100s", userstyle, cp); 1408 fail++; 1409 } 1410 free(userstyle); 1411 free(cp); 1412 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1413 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1414 fatal_fr(r, "parse method"); 1415 if (strcmp("publickey", cp) != 0) { 1416 if (strcmp("publickey-hostbound-v00@openssh.com", cp) == 0) 1417 hostbound = 1; 1418 else 1419 fail++; 1420 } 1421 free(cp); 1422 if ((r = sshbuf_get_u8(b, &type)) != 0) 1423 fatal_fr(r, "parse pktype"); 1424 if (type == 0) 1425 fail++; 1426 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1427 (r = sshbuf_skip_string(b)) != 0 || /* pkblob */ 1428 (hostbound && (r = sshkey_froms(b, &hostkey)) != 0)) 1429 fatal_fr(r, "parse pk"); 1430 if (sshbuf_len(b) != 0) 1431 fail++; 1432 sshbuf_free(b); 1433 if (hostkey != NULL) { 1434 /* 1435 * Ensure this is actually one of our hostkeys; unfortunately 1436 * can't check ssh->kex->initial_hostkey directly at this point 1437 * as packet state has not yet been exported to monitor. 1438 */ 1439 if (get_hostkey_index(hostkey, 1, ssh) == -1) 1440 fatal_f("hostbound hostkey does not match"); 1441 sshkey_free(hostkey); 1442 } 1443 return (fail == 0); 1444 } 1445 1446 static int 1447 monitor_valid_hostbasedblob(const u_char *data, u_int datalen, 1448 const char *cuser, const char *chost) 1449 { 1450 struct sshbuf *b; 1451 const u_char *p; 1452 char *cp, *userstyle; 1453 size_t len; 1454 int r, fail = 0; 1455 u_char type; 1456 1457 if ((b = sshbuf_from(data, datalen)) == NULL) 1458 fatal_f("sshbuf_new"); 1459 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1460 fatal_fr(r, "parse sessionid"); 1461 1462 if ((session_id2 == NULL) || 1463 (len != session_id2_len) || 1464 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1465 fail++; 1466 1467 if ((r = sshbuf_get_u8(b, &type)) != 0) 1468 fatal_fr(r, "parse type"); 1469 if (type != SSH2_MSG_USERAUTH_REQUEST) 1470 fail++; 1471 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1472 fatal_fr(r, "parse userstyle"); 1473 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1474 authctxt->style ? ":" : "", 1475 authctxt->style ? authctxt->style : ""); 1476 if (strcmp(userstyle, cp) != 0) { 1477 logit("wrong user name passed to monitor: " 1478 "expected %s != %.100s", userstyle, cp); 1479 fail++; 1480 } 1481 free(userstyle); 1482 free(cp); 1483 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1484 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1485 fatal_fr(r, "parse method"); 1486 if (strcmp(cp, "hostbased") != 0) 1487 fail++; 1488 free(cp); 1489 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1490 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1491 fatal_fr(r, "parse pk"); 1492 1493 /* verify client host, strip trailing dot if necessary */ 1494 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1495 fatal_fr(r, "parse host"); 1496 if (((len = strlen(cp)) > 0) && cp[len - 1] == '.') 1497 cp[len - 1] = '\0'; 1498 if (strcmp(cp, chost) != 0) 1499 fail++; 1500 free(cp); 1501 1502 /* verify client user */ 1503 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1504 fatal_fr(r, "parse ruser"); 1505 if (strcmp(cp, cuser) != 0) 1506 fail++; 1507 free(cp); 1508 1509 if (sshbuf_len(b) != 0) 1510 fail++; 1511 sshbuf_free(b); 1512 return (fail == 0); 1513 } 1514 1515 int 1516 mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m) 1517 { 1518 struct sshkey *key; 1519 const u_char *signature, *data, *blob; 1520 char *sigalg = NULL, *fp = NULL; 1521 size_t signaturelen, datalen, bloblen; 1522 int r, ret, req_presence = 0, req_verify = 0, valid_data = 0; 1523 int encoded_ret; 1524 struct sshkey_sig_details *sig_details = NULL; 1525 1526 if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 || 1527 (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 || 1528 (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 || 1529 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0) 1530 fatal_fr(r, "parse"); 1531 1532 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1533 !monitor_allowed_key(blob, bloblen)) 1534 fatal_f("bad key, not previously allowed"); 1535 1536 /* Empty signature algorithm means NULL. */ 1537 if (*sigalg == '\0') { 1538 free(sigalg); 1539 sigalg = NULL; 1540 } 1541 1542 /* XXX use sshkey_froms here; need to change key_blob, etc. */ 1543 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0) 1544 fatal_fr(r, "parse key"); 1545 1546 switch (key_blobtype) { 1547 case MM_USERKEY: 1548 valid_data = monitor_valid_userblob(ssh, data, datalen); 1549 auth_method = "publickey"; 1550 break; 1551 case MM_HOSTKEY: 1552 valid_data = monitor_valid_hostbasedblob(data, datalen, 1553 hostbased_cuser, hostbased_chost); 1554 auth_method = "hostbased"; 1555 break; 1556 default: 1557 valid_data = 0; 1558 break; 1559 } 1560 if (!valid_data) 1561 fatal_f("bad %s signature data blob", 1562 key_blobtype == MM_USERKEY ? "userkey" : 1563 (key_blobtype == MM_HOSTKEY ? "hostkey" : "unknown")); 1564 1565 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 1566 SSH_FP_DEFAULT)) == NULL) 1567 fatal_f("sshkey_fingerprint failed"); 1568 1569 ret = sshkey_verify(key, signature, signaturelen, data, datalen, 1570 sigalg, ssh->compat, &sig_details); 1571 debug3_f("%s %s signature using %s %s%s%s", auth_method, 1572 sshkey_type(key), sigalg == NULL ? "default" : sigalg, 1573 (ret == 0) ? "verified" : "unverified", 1574 (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : ""); 1575 1576 if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) { 1577 req_presence = (options.pubkey_auth_options & 1578 PUBKEYAUTH_TOUCH_REQUIRED) || 1579 !key_opts->no_require_user_presence; 1580 if (req_presence && 1581 (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) { 1582 error("public key %s %s signature for %s%s from %.128s " 1583 "port %d rejected: user presence " 1584 "(authenticator touch) requirement not met ", 1585 sshkey_type(key), fp, 1586 authctxt->valid ? "" : "invalid user ", 1587 authctxt->user, ssh_remote_ipaddr(ssh), 1588 ssh_remote_port(ssh)); 1589 ret = SSH_ERR_SIGNATURE_INVALID; 1590 } 1591 req_verify = (options.pubkey_auth_options & 1592 PUBKEYAUTH_VERIFY_REQUIRED) || key_opts->require_verify; 1593 if (req_verify && 1594 (sig_details->sk_flags & SSH_SK_USER_VERIFICATION_REQD) == 0) { 1595 error("public key %s %s signature for %s%s from %.128s " 1596 "port %d rejected: user verification requirement " 1597 "not met ", sshkey_type(key), fp, 1598 authctxt->valid ? "" : "invalid user ", 1599 authctxt->user, ssh_remote_ipaddr(ssh), 1600 ssh_remote_port(ssh)); 1601 ret = SSH_ERR_SIGNATURE_INVALID; 1602 } 1603 } 1604 auth2_record_key(authctxt, ret == 0, key); 1605 1606 if (key_blobtype == MM_USERKEY && ret == 0) 1607 auth_activate_options(ssh, key_opts); 1608 monitor_reset_key_state(); 1609 1610 sshbuf_reset(m); 1611 1612 /* encode ret != 0 as positive integer, since we're sending u32 */ 1613 encoded_ret = (ret != 0); 1614 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 || 1615 (r = sshbuf_put_u8(m, sig_details != NULL)) != 0) 1616 fatal_fr(r, "assemble"); 1617 if (sig_details != NULL) { 1618 if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 || 1619 (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0) 1620 fatal_fr(r, "assemble sk"); 1621 } 1622 sshkey_sig_details_free(sig_details); 1623 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1624 1625 free(sigalg); 1626 free(fp); 1627 sshkey_free(key); 1628 1629 return ret == 0; 1630 } 1631 1632 static void 1633 mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw) 1634 { 1635 socklen_t fromlen; 1636 struct sockaddr_storage from; 1637 1638 /* 1639 * Get IP address of client. If the connection is not a socket, let 1640 * the address be 0.0.0.0. 1641 */ 1642 memset(&from, 0, sizeof(from)); 1643 fromlen = sizeof(from); 1644 if (ssh_packet_connection_is_on_socket(ssh)) { 1645 if (getpeername(ssh_packet_get_connection_in(ssh), 1646 (struct sockaddr *)&from, &fromlen) == -1) { 1647 debug("getpeername: %.100s", strerror(errno)); 1648 cleanup_exit(255); 1649 } 1650 } 1651 /* Record that there was a login on that tty from the remote host. */ 1652 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1653 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1654 (struct sockaddr *)&from, fromlen); 1655 } 1656 1657 static void 1658 mm_session_close(Session *s) 1659 { 1660 debug3_f("session %d pid %ld", s->self, (long)s->pid); 1661 if (s->ttyfd != -1) { 1662 debug3_f("tty %s ptyfd %d", s->tty, s->ptyfd); 1663 session_pty_cleanup2(s); 1664 } 1665 session_unused(s->self); 1666 } 1667 1668 int 1669 mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m) 1670 { 1671 extern struct monitor *pmonitor; 1672 Session *s; 1673 int r, res, fd0; 1674 1675 debug3_f("entering"); 1676 1677 sshbuf_reset(m); 1678 s = session_new(); 1679 if (s == NULL) 1680 goto error; 1681 s->authctxt = authctxt; 1682 s->pw = authctxt->pw; 1683 s->pid = pmonitor->m_pid; 1684 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1685 if (res == 0) 1686 goto error; 1687 pty_setowner(authctxt->pw, s->tty); 1688 1689 if ((r = sshbuf_put_u32(m, 1)) != 0 || 1690 (r = sshbuf_put_cstring(m, s->tty)) != 0) 1691 fatal_fr(r, "assemble"); 1692 1693 /* We need to trick ttyslot */ 1694 if (dup2(s->ttyfd, 0) == -1) 1695 fatal_f("dup2"); 1696 1697 mm_record_login(ssh, s, authctxt->pw); 1698 1699 /* Now we can close the file descriptor again */ 1700 close(0); 1701 1702 /* send messages generated by record_login */ 1703 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0) 1704 fatal_fr(r, "assemble loginmsg"); 1705 sshbuf_reset(loginmsg); 1706 1707 mm_request_send(sock, MONITOR_ANS_PTY, m); 1708 1709 if (mm_send_fd(sock, s->ptyfd) == -1 || 1710 mm_send_fd(sock, s->ttyfd) == -1) 1711 fatal_f("send fds failed"); 1712 1713 /* make sure nothing uses fd 0 */ 1714 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1715 fatal_f("open(/dev/null): %s", strerror(errno)); 1716 if (fd0 != 0) 1717 error_f("fd0 %d != 0", fd0); 1718 1719 /* slave side of pty is not needed */ 1720 close(s->ttyfd); 1721 s->ttyfd = s->ptyfd; 1722 /* no need to dup() because nobody closes ptyfd */ 1723 s->ptymaster = s->ptyfd; 1724 1725 debug3_f("tty %s ptyfd %d", s->tty, s->ttyfd); 1726 1727 return (0); 1728 1729 error: 1730 if (s != NULL) 1731 mm_session_close(s); 1732 if ((r = sshbuf_put_u32(m, 0)) != 0) 1733 fatal_fr(r, "assemble 0"); 1734 mm_request_send(sock, MONITOR_ANS_PTY, m); 1735 return (0); 1736 } 1737 1738 int 1739 mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m) 1740 { 1741 Session *s; 1742 char *tty; 1743 int r; 1744 1745 debug3_f("entering"); 1746 1747 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0) 1748 fatal_fr(r, "parse tty"); 1749 if ((s = session_by_tty(tty)) != NULL) 1750 mm_session_close(s); 1751 sshbuf_reset(m); 1752 free(tty); 1753 return (0); 1754 } 1755 1756 int 1757 mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req) 1758 { 1759 extern struct monitor *pmonitor; 1760 int res, status; 1761 1762 debug3_f("tearing down sessions"); 1763 1764 /* The child is terminating */ 1765 session_destroy_all(ssh, &mm_session_close); 1766 1767 #ifdef USE_PAM 1768 if (options.use_pam) 1769 sshpam_cleanup(); 1770 #endif 1771 1772 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1773 if (errno != EINTR) 1774 exit(1); 1775 1776 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1777 1778 /* Terminate process */ 1779 exit(res); 1780 } 1781 1782 #ifdef SSH_AUDIT_EVENTS 1783 /* Report that an audit event occurred */ 1784 int 1785 mm_answer_audit_event(struct ssh *ssh, int socket, struct sshbuf *m) 1786 { 1787 u_int n; 1788 ssh_audit_event_t event; 1789 int r; 1790 1791 debug3("%s entering", __func__); 1792 1793 if ((r = sshbuf_get_u32(m, &n)) != 0) 1794 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1795 event = (ssh_audit_event_t)n; 1796 switch (event) { 1797 case SSH_AUTH_FAIL_PUBKEY: 1798 case SSH_AUTH_FAIL_HOSTBASED: 1799 case SSH_AUTH_FAIL_GSSAPI: 1800 case SSH_LOGIN_EXCEED_MAXTRIES: 1801 case SSH_LOGIN_ROOT_DENIED: 1802 case SSH_CONNECTION_CLOSE: 1803 case SSH_INVALID_USER: 1804 audit_event(ssh, event); 1805 break; 1806 default: 1807 fatal("Audit event type %d not permitted", event); 1808 } 1809 1810 return (0); 1811 } 1812 1813 int 1814 mm_answer_audit_command(struct ssh *ssh, int socket, struct sshbuf *m) 1815 { 1816 char *cmd; 1817 int r; 1818 1819 debug3("%s entering", __func__); 1820 if ((r = sshbuf_get_cstring(m, &cmd, NULL)) != 0) 1821 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1822 /* sanity check command, if so how? */ 1823 audit_run_command(cmd); 1824 free(cmd); 1825 return (0); 1826 } 1827 #endif /* SSH_AUDIT_EVENTS */ 1828 1829 void 1830 monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor) 1831 { 1832 ssh_clear_newkeys(ssh, MODE_IN); 1833 ssh_clear_newkeys(ssh, MODE_OUT); 1834 sshbuf_free(child_state); 1835 child_state = NULL; 1836 } 1837 1838 void 1839 monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor) 1840 { 1841 struct kex *kex; 1842 int r; 1843 1844 debug3_f("packet_set_state"); 1845 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1846 fatal_fr(r, "packet_set_state"); 1847 sshbuf_free(child_state); 1848 child_state = NULL; 1849 if ((kex = ssh->kex) == NULL) 1850 fatal_f("internal error: ssh->kex == NULL"); 1851 if (session_id2_len != sshbuf_len(ssh->kex->session_id)) { 1852 fatal_f("incorrect session id length %zu (expected %u)", 1853 sshbuf_len(ssh->kex->session_id), session_id2_len); 1854 } 1855 if (memcmp(sshbuf_ptr(ssh->kex->session_id), session_id2, 1856 session_id2_len) != 0) 1857 fatal_f("session ID mismatch"); 1858 /* XXX set callbacks */ 1859 #ifdef WITH_OPENSSL 1860 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server; 1861 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server; 1862 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server; 1863 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server; 1864 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server; 1865 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1866 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1867 # ifdef OPENSSL_HAS_ECC 1868 kex->kex[KEX_ECDH_SHA2] = kex_gen_server; 1869 # endif 1870 #endif /* WITH_OPENSSL */ 1871 kex->kex[KEX_C25519_SHA256] = kex_gen_server; 1872 kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server; 1873 kex->kex[KEX_KEM_MLKEM768X25519_SHA256] = kex_gen_server; 1874 kex->load_host_public_key=&get_hostkey_public_by_type; 1875 kex->load_host_private_key=&get_hostkey_private_by_type; 1876 kex->host_key_index=&get_hostkey_index; 1877 kex->sign = sshd_hostkey_sign; 1878 } 1879 1880 /* This function requires careful sanity checking */ 1881 1882 void 1883 mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor) 1884 { 1885 debug3_f("Waiting for new keys"); 1886 1887 if ((child_state = sshbuf_new()) == NULL) 1888 fatal_f("sshbuf_new failed"); 1889 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1890 child_state); 1891 debug3_f("GOT new keys"); 1892 } 1893 1894 1895 /* XXX */ 1896 1897 #define FD_CLOSEONEXEC(x) do { \ 1898 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1899 fatal("fcntl(%d, F_SETFD)", x); \ 1900 } while (0) 1901 1902 static void 1903 monitor_openfds(struct monitor *mon, int do_logfds) 1904 { 1905 int pair[2]; 1906 #ifdef SO_ZEROIZE 1907 int on = 1; 1908 #endif 1909 1910 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1911 fatal_f("socketpair: %s", strerror(errno)); 1912 #ifdef SO_ZEROIZE 1913 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1914 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno)); 1915 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1916 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno)); 1917 #endif 1918 FD_CLOSEONEXEC(pair[0]); 1919 FD_CLOSEONEXEC(pair[1]); 1920 mon->m_recvfd = pair[0]; 1921 mon->m_sendfd = pair[1]; 1922 1923 if (do_logfds) { 1924 if (pipe(pair) == -1) 1925 fatal_f("pipe: %s", strerror(errno)); 1926 FD_CLOSEONEXEC(pair[0]); 1927 FD_CLOSEONEXEC(pair[1]); 1928 mon->m_log_recvfd = pair[0]; 1929 mon->m_log_sendfd = pair[1]; 1930 } else 1931 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1932 } 1933 1934 struct monitor * 1935 monitor_init(void) 1936 { 1937 struct monitor *mon; 1938 1939 mon = xcalloc(1, sizeof(*mon)); 1940 monitor_openfds(mon, 1); 1941 1942 return mon; 1943 } 1944 1945 void 1946 monitor_reinit(struct monitor *mon) 1947 { 1948 monitor_openfds(mon, 0); 1949 } 1950 1951 #ifdef GSSAPI 1952 int 1953 mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1954 { 1955 gss_OID_desc goid; 1956 OM_uint32 major; 1957 size_t len; 1958 u_char *p; 1959 int r; 1960 1961 if (!options.gss_authentication) 1962 fatal_f("GSSAPI authentication not enabled"); 1963 1964 if ((r = sshbuf_get_string(m, &p, &len)) != 0) 1965 fatal_fr(r, "parse"); 1966 goid.elements = p; 1967 goid.length = len; 1968 1969 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1970 1971 free(goid.elements); 1972 1973 sshbuf_reset(m); 1974 if ((r = sshbuf_put_u32(m, major)) != 0) 1975 fatal_fr(r, "assemble"); 1976 1977 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1978 1979 /* Now we have a context, enable the step */ 1980 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1981 1982 return (0); 1983 } 1984 1985 int 1986 mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1987 { 1988 gss_buffer_desc in; 1989 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1990 OM_uint32 major, minor; 1991 OM_uint32 flags = 0; /* GSI needs this */ 1992 int r; 1993 1994 if (!options.gss_authentication) 1995 fatal_f("GSSAPI authentication not enabled"); 1996 1997 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0) 1998 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1999 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 2000 free(in.value); 2001 2002 sshbuf_reset(m); 2003 if ((r = sshbuf_put_u32(m, major)) != 0 || 2004 (r = sshbuf_put_string(m, out.value, out.length)) != 0 || 2005 (r = sshbuf_put_u32(m, flags)) != 0) 2006 fatal_fr(r, "assemble"); 2007 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 2008 2009 gss_release_buffer(&minor, &out); 2010 2011 if (major == GSS_S_COMPLETE) { 2012 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 2013 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 2014 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 2015 } 2016 return (0); 2017 } 2018 2019 int 2020 mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m) 2021 { 2022 gss_buffer_desc gssbuf, mic; 2023 OM_uint32 ret; 2024 int r; 2025 2026 if (!options.gss_authentication) 2027 fatal_f("GSSAPI authentication not enabled"); 2028 2029 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 || 2030 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0) 2031 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 2032 2033 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 2034 2035 free(gssbuf.value); 2036 free(mic.value); 2037 2038 sshbuf_reset(m); 2039 if ((r = sshbuf_put_u32(m, ret)) != 0) 2040 fatal_fr(r, "assemble"); 2041 2042 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 2043 2044 if (!GSS_ERROR(ret)) 2045 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 2046 2047 return (0); 2048 } 2049 2050 int 2051 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m) 2052 { 2053 int r, authenticated; 2054 const char *displayname; 2055 2056 if (!options.gss_authentication) 2057 fatal_f("GSSAPI authentication not enabled"); 2058 2059 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 2060 2061 sshbuf_reset(m); 2062 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 2063 fatal_fr(r, "assemble"); 2064 2065 debug3_f("sending result %d", authenticated); 2066 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 2067 2068 auth_method = "gssapi-with-mic"; 2069 2070 if ((displayname = ssh_gssapi_displayname()) != NULL) 2071 auth2_record_info(authctxt, "%s", displayname); 2072 2073 /* Monitor loop will terminate if authenticated */ 2074 return (authenticated); 2075 } 2076 #endif /* GSSAPI */ 2077 2078