1 /* $NetBSD: monitor.c,v 1.51 2026/04/08 18:58:41 christos Exp $ */ 2 /* $OpenBSD: monitor.c,v 1.255 2026/03/28 05:06:16 djm Exp $ */ 3 4 /* 5 * Copyright 2002 Niels Provos <provos (at) citi.umich.edu> 6 * Copyright 2002 Markus Friedl <markus (at) openbsd.org> 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30 #include "includes.h" 31 __RCSID("$NetBSD: monitor.c,v 1.51 2026/04/08 18:58:41 christos Exp $"); 32 #include <sys/types.h> 33 #include <sys/wait.h> 34 #include <sys/socket.h> 35 #include <sys/tree.h> 36 #include <sys/queue.h> 37 38 #include <errno.h> 39 #include <fcntl.h> 40 #include <limits.h> 41 #include <paths.h> 42 #include <poll.h> 43 #include <pwd.h> 44 #include <signal.h> 45 #include <stdarg.h> 46 #include <unistd.h> 47 #include <stdint.h> 48 #include <stdio.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <unistd.h> 52 53 #ifdef WITH_OPENSSL 54 #include <openssl/dh.h> 55 #endif 56 57 58 #include "atomicio.h" 59 #include "xmalloc.h" 60 #include "ssh.h" 61 #include "sshkey.h" 62 #include "sshbuf.h" 63 #include "hostfile.h" 64 #include "auth.h" 65 #include "cipher.h" 66 #include "kex.h" 67 #include "dh.h" 68 #include "packet.h" 69 #include "auth-options.h" 70 #include "sshpty.h" 71 #include "channels.h" 72 #include "session.h" 73 #include "sshlogin.h" 74 #include "canohost.h" 75 #include "log.h" 76 #include "misc.h" 77 #include "servconf.h" 78 #include "monitor.h" 79 #ifdef GSSAPI 80 #include "ssh-gss.h" 81 #endif 82 #include "monitor_wrap.h" 83 #include "monitor_fdpass.h" 84 #include "compat.h" 85 #include "ssh2.h" 86 #include "authfd.h" 87 #include "match.h" 88 #include "ssherr.h" 89 #include "sk-api.h" 90 #include "srclimit.h" 91 92 #include "pfilter.h" 93 94 #ifdef GSSAPI 95 static Gssctxt *gsscontext = NULL; 96 #endif 97 98 /* Imports */ 99 extern ServerOptions options; 100 extern u_int utmp_len; 101 extern struct sshbuf *cfg; 102 extern struct sshbuf *loginmsg; 103 extern struct include_list includes; 104 extern struct sshauthopt *auth_opts; /* XXX move to permanent ssh->authctxt? */ 105 106 /* State exported from the child */ 107 static struct sshbuf *child_state; 108 109 /* Functions on the monitor that answer unprivileged requests */ 110 111 int mm_answer_moduli(struct ssh *, int, struct sshbuf *); 112 int mm_answer_setcompat(struct ssh *, int, struct sshbuf *); 113 int mm_answer_sign(struct ssh *, int, struct sshbuf *); 114 int mm_answer_pwnamallow(struct ssh *, int, struct sshbuf *); 115 int mm_answer_auth2_read_banner(struct ssh *, int, struct sshbuf *); 116 int mm_answer_authserv(struct ssh *, int, struct sshbuf *); 117 int mm_answer_authpassword(struct ssh *, int, struct sshbuf *); 118 int mm_answer_bsdauthquery(struct ssh *, int, struct sshbuf *); 119 int mm_answer_bsdauthrespond(struct ssh *, int, struct sshbuf *); 120 int mm_answer_keyallowed(struct ssh *, int, struct sshbuf *); 121 int mm_answer_keyverify(struct ssh *, int, struct sshbuf *); 122 int mm_answer_pty(struct ssh *, int, struct sshbuf *); 123 int mm_answer_pty_cleanup(struct ssh *, int, struct sshbuf *); 124 int mm_answer_term(struct ssh *, int, struct sshbuf *); 125 int mm_answer_state(struct ssh *, int, struct sshbuf *); 126 127 #ifdef USE_PAM 128 int mm_answer_pam_start(struct ssh *, int, struct sshbuf *); 129 int mm_answer_pam_account(struct ssh *, int, struct sshbuf *); 130 int mm_answer_pam_init_ctx(struct ssh *, int, struct sshbuf *); 131 int mm_answer_pam_query(struct ssh *, int, struct sshbuf *); 132 int mm_answer_pam_respond(struct ssh *, int, struct sshbuf *); 133 int mm_answer_pam_free_ctx(struct ssh *, int, struct sshbuf *); 134 #endif 135 136 #ifdef KRB5 137 int mm_answer_krb5(struct ssh *, int, struct sshbuf *); 138 #endif 139 140 #ifdef GSSAPI 141 int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *); 142 int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *); 143 int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *); 144 int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *); 145 #endif 146 147 static Authctxt *authctxt; 148 149 /* local state for key verify */ 150 static u_char *key_blob = NULL; 151 static size_t key_bloblen = 0; 152 static u_int key_blobtype = MM_NOKEY; 153 static struct sshauthopt *key_opts = NULL; 154 static char *hostbased_cuser = NULL; 155 static char *hostbased_chost = NULL; 156 static const char *auth_method = "unknown"; 157 static const char *auth_submethod = NULL; 158 static u_int session_id2_len = 0; 159 static u_char *session_id2 = NULL; 160 static pid_t monitor_child_pid; 161 static int auth_attempted = 0; 162 static int invalid_user = 0; 163 static int compat_set = 0; 164 165 struct mon_table { 166 enum monitor_reqtype type; 167 int flags; 168 int (*f)(struct ssh *, int, struct sshbuf *); 169 }; 170 171 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 172 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 173 #define MON_ONCE 0x0010 /* Disable after calling */ 174 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 175 176 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 177 178 #define MON_PERMIT 0x1000 /* Request is permitted */ 179 180 static int monitor_read(struct ssh *, struct monitor *, struct mon_table *, 181 struct mon_table **); 182 static int monitor_read_log(struct monitor *); 183 184 struct mon_table mon_dispatch_proto20[] = { 185 {MONITOR_REQ_STATE, MON_ONCE, mm_answer_state}, 186 #ifdef WITH_OPENSSL 187 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 188 #endif 189 {MONITOR_REQ_SETCOMPAT, MON_ONCE, mm_answer_setcompat}, 190 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 191 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 192 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 193 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 194 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 195 #ifdef USE_PAM 196 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 197 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 198 {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx}, 199 {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query}, 200 {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond}, 201 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 202 #endif 203 #ifdef BSD_AUTH 204 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 205 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 206 #endif 207 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 208 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 209 #ifdef KRB5 210 {MONITOR_REQ_KRB5, MON_ONCE|MON_AUTH, mm_answer_krb5}, 211 #endif 212 #ifdef GSSAPI 213 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 214 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx}, 215 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok}, 216 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic}, 217 #endif 218 {0, 0, NULL} 219 }; 220 221 struct mon_table mon_dispatch_postauth20[] = { 222 {MONITOR_REQ_STATE, MON_ONCE, mm_answer_state}, 223 #ifdef WITH_OPENSSL 224 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 225 #endif 226 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 227 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 228 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 229 {MONITOR_REQ_TERM, 0, mm_answer_term}, 230 {0, 0, NULL} 231 }; 232 233 struct mon_table *mon_dispatch; 234 235 /* Specifies if a certain message is allowed at the moment */ 236 static void 237 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 238 { 239 while (ent->f != NULL) { 240 if (ent->type == type) { 241 ent->flags &= ~MON_PERMIT; 242 ent->flags |= permit ? MON_PERMIT : 0; 243 return; 244 } 245 ent++; 246 } 247 } 248 249 static void 250 monitor_permit_authentications(int permit) 251 { 252 struct mon_table *ent = mon_dispatch; 253 254 while (ent->f != NULL) { 255 if (ent->flags & MON_AUTH) { 256 ent->flags &= ~MON_PERMIT; 257 ent->flags |= permit ? MON_PERMIT : 0; 258 } 259 ent++; 260 } 261 } 262 263 void 264 monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor) 265 { 266 struct mon_table *ent; 267 int status, authenticated = 0, partial = 0; 268 269 debug3("preauth child monitor started"); 270 271 authctxt = (Authctxt *)ssh->authctxt; 272 if (pmonitor->m_recvfd >= 0) 273 close(pmonitor->m_recvfd); 274 if (pmonitor->m_log_sendfd >= 0) 275 close(pmonitor->m_log_sendfd); 276 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 277 278 memset(authctxt, 0, sizeof(*authctxt)); 279 ssh->authctxt = authctxt; 280 281 mon_dispatch = mon_dispatch_proto20; 282 /* Permit requests for state, moduli and signatures */ 283 monitor_permit(mon_dispatch, MONITOR_REQ_STATE, 1); 284 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 285 monitor_permit(mon_dispatch, MONITOR_REQ_SETCOMPAT, 1); 286 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 287 288 /* The first few requests do not require asynchronous access */ 289 while (!authenticated) { 290 partial = 0; 291 auth_method = "unknown"; 292 auth_submethod = NULL; 293 auth2_authctxt_reset_info(authctxt); 294 295 authenticated = (monitor_read(ssh, pmonitor, 296 mon_dispatch, &ent) == 1); 297 298 /* Record that auth was attempted to set exit status later */ 299 if ((ent->flags & MON_AUTH) != 0) 300 auth_attempted = 1; 301 302 /* Special handling for multiple required authentications */ 303 if (options.num_auth_methods != 0) { 304 if (authenticated && 305 !auth2_update_methods_lists(authctxt, 306 auth_method, auth_submethod)) { 307 debug3_f("method %s: partial", auth_method); 308 authenticated = 0; 309 partial = 1; 310 } 311 } 312 313 if (authenticated) { 314 if (!(ent->flags & MON_AUTHDECIDE)) 315 fatal_f("unexpected authentication from %d", 316 ent->type); 317 if (authctxt->pw->pw_uid == 0 && 318 !auth_root_allowed(ssh, auth_method)) 319 authenticated = 0; 320 #ifdef USE_PAM 321 /* PAM needs to perform account checks after auth */ 322 if (options.use_pam && authenticated) { 323 struct sshbuf *m; 324 325 if ((m = sshbuf_new()) == NULL) 326 fatal("%s: sshbuf_new failed", __func__); 327 328 mm_request_receive_expect(pmonitor->m_sendfd, 329 MONITOR_REQ_PAM_ACCOUNT, m); 330 authenticated = mm_answer_pam_account(ssh, pmonitor->m_sendfd, m); 331 sshbuf_free(m); 332 } 333 #endif 334 } 335 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 336 auth_log(ssh, authenticated, partial, 337 auth_method, auth_submethod); 338 if (!partial && !authenticated) 339 authctxt->failures++; 340 if (authenticated || partial) { 341 auth2_update_session_info(authctxt, 342 auth_method, auth_submethod); 343 } 344 } 345 if (authctxt->failures > options.max_authtries) { 346 pfilter_notify(1); 347 /* Shouldn't happen */ 348 fatal_f("privsep child made too many authentication " 349 "attempts"); 350 } 351 } 352 353 if (!authctxt->valid) { 354 pfilter_notify(1); 355 fatal_f("authenticated invalid user"); 356 } 357 if (strcmp(auth_method, "unknown") == 0) { 358 pfilter_notify(1); 359 fatal_f("authentication method name unknown"); 360 } 361 362 debug_f("user %s authenticated by privileged process", authctxt->user); 363 auth_attempted = 0; 364 ssh->authctxt = NULL; 365 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 366 367 mm_get_keystate(ssh, pmonitor); 368 369 /* Drain any buffered messages from the child */ 370 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 371 ; 372 373 /* Wait for the child's exit status */ 374 while (waitpid(pmonitor->m_pid, &status, 0) == -1) { 375 if (errno == EINTR) 376 continue; 377 fatal_f("waitpid: %s", strerror(errno)); 378 } 379 if (WIFEXITED(status)) { 380 if (WEXITSTATUS(status) != 0) 381 fatal_f("preauth child %ld exited with status %d", 382 (long)pmonitor->m_pid, WEXITSTATUS(status)); 383 } else if (WIFSIGNALED(status)) { 384 fatal_f("preauth child %ld terminated by signal %d", 385 (long)pmonitor->m_pid, WTERMSIG(status)); 386 } 387 debug3_f("preauth child %ld terminated successfully", 388 (long)pmonitor->m_pid); 389 390 if (pmonitor->m_recvfd >= 0) 391 close(pmonitor->m_recvfd); 392 if (pmonitor->m_log_sendfd >= 0) 393 close(pmonitor->m_log_sendfd); 394 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 395 pmonitor->m_pid = -1; 396 } 397 398 static void 399 monitor_set_child_handler(pid_t pid) 400 { 401 monitor_child_pid = pid; 402 } 403 404 static void 405 monitor_child_handler(int sig) 406 { 407 kill(monitor_child_pid, sig); 408 } 409 410 void 411 monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor) 412 { 413 close(pmonitor->m_recvfd); 414 pmonitor->m_recvfd = -1; 415 416 monitor_set_child_handler(pmonitor->m_pid); 417 ssh_signal(SIGHUP, &monitor_child_handler); 418 ssh_signal(SIGTERM, &monitor_child_handler); 419 ssh_signal(SIGINT, &monitor_child_handler); 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 *unused) 591 { 592 struct sshbuf *m = NULL, *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 debug_f("config len %zu", sshbuf_len(cfg)); 599 600 if ((m = sshbuf_new()) == NULL || 601 (inc = sshbuf_new()) == NULL || 602 (opts = sshbuf_new()) == NULL || 603 (confdata = sshbuf_new()) == NULL) 604 fatal_f("sshbuf_new failed"); 605 606 /* XXX unnecessary? */ 607 /* pack includes into a string */ 608 TAILQ_FOREACH(item, &includes, entry) { 609 if ((r = sshbuf_put_cstring(inc, item->selector)) != 0 || 610 (r = sshbuf_put_cstring(inc, item->filename)) != 0 || 611 (r = sshbuf_put_stringb(inc, item->contents)) != 0) 612 fatal_fr(r, "compose includes"); 613 } 614 615 hostkeys = pack_hostkeys(); 616 617 /* 618 * Protocol from monitor to unpriv privsep process: 619 * string configuration 620 * uint64 timing_secret XXX move delays to monitor and remove 621 * string host_keys[] { 622 * string public_key 623 * string certificate 624 * } 625 * string server_banner 626 * string client_banner 627 * string included_files[] { 628 * string selector 629 * string filename 630 * string contents 631 * } 632 * string configuration_data (postauth) 633 * string keystate (postauth) 634 * string authenticated_user (postauth) 635 * string session_info (postauth) 636 * string authopts (postauth) 637 */ 638 if ((r = sshbuf_put_stringb(m, cfg)) != 0 || 639 (r = sshbuf_put_u64(m, options.timing_secret)) != 0 || 640 (r = sshbuf_put_stringb(m, hostkeys)) != 0 || 641 (r = sshbuf_put_stringb(m, ssh->kex->server_version)) != 0 || 642 (r = sshbuf_put_stringb(m, ssh->kex->client_version)) != 0 || 643 (r = sshbuf_put_stringb(m, inc)) != 0) 644 fatal_fr(r, "compose config"); 645 646 postauth = (authctxt && authctxt->pw && authctxt->authenticated); 647 if (postauth) { 648 /* XXX shouldn't be reachable */ 649 fatal_f("internal error: called in postauth"); 650 } 651 652 sshbuf_free(inc); 653 sshbuf_free(opts); 654 sshbuf_free(confdata); 655 sshbuf_free(hostkeys); 656 657 mm_request_send(sock, MONITOR_ANS_STATE, m); 658 sshbuf_free(m); 659 debug3_f("done"); 660 661 return (0); 662 } 663 664 #ifdef WITH_OPENSSL 665 int 666 mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m) 667 { 668 DH *dh; 669 const BIGNUM *dh_p, *dh_g; 670 int r; 671 u_int min, want, max; 672 673 if ((r = sshbuf_get_u32(m, &min)) != 0 || 674 (r = sshbuf_get_u32(m, &want)) != 0 || 675 (r = sshbuf_get_u32(m, &max)) != 0) 676 fatal_fr(r, "parse"); 677 678 debug3_f("got parameters: %d %d %d", min, want, max); 679 /* We need to check here, too, in case the child got corrupted */ 680 if (max < min || want < min || max < want) 681 fatal_f("bad parameters: %d %d %d", min, want, max); 682 683 sshbuf_reset(m); 684 685 dh = choose_dh(min, want, max); 686 if (dh == NULL) { 687 if ((r = sshbuf_put_u8(m, 0)) != 0) 688 fatal_fr(r, "assemble empty"); 689 } else { 690 /* Send first bignum */ 691 DH_get0_pqg(dh, &dh_p, NULL, &dh_g); 692 if ((r = sshbuf_put_u8(m, 1)) != 0 || 693 (r = sshbuf_put_bignum2(m, dh_p)) != 0 || 694 (r = sshbuf_put_bignum2(m, dh_g)) != 0) 695 fatal_fr(r, "assemble"); 696 697 DH_free(dh); 698 } 699 mm_request_send(sock, MONITOR_ANS_MODULI, m); 700 return (0); 701 } 702 #endif 703 704 int 705 mm_answer_setcompat(struct ssh *ssh, int sock, struct sshbuf *m) 706 { 707 int r; 708 709 debug3_f("entering"); 710 711 if ((r = sshbuf_get_u32(m, &ssh->compat)) != 0) 712 fatal_fr(r, "parse"); 713 compat_set = 1; 714 715 return (0); 716 } 717 718 int 719 mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m) 720 { 721 extern int auth_sock; /* XXX move to state struct? */ 722 struct sshkey *pubkey, *key; 723 struct sshbuf *sigbuf = NULL; 724 u_char *p = NULL, *signature = NULL; 725 char *alg = NULL; 726 size_t datlen, siglen; 727 int r, is_proof = 0, keyid; 728 u_int compat; 729 const char proof_req[] = "hostkeys-prove-00 (at) openssh.com"; 730 731 debug3_f("entering"); 732 733 /* Make sure the unpriv process sent the compat bits already */ 734 if (!compat_set) 735 fatal_f("state error: setcompat never called"); 736 737 if ((r = sshkey_froms(m, &pubkey)) != 0 || 738 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 739 (r = sshbuf_get_cstring(m, &alg, NULL)) != 0 || 740 (r = sshbuf_get_u32(m, &compat)) != 0) 741 fatal_fr(r, "parse"); 742 743 if ((keyid = get_hostkey_index(pubkey, 1, ssh)) == -1) 744 fatal_f("unknown hostkey"); 745 debug_f("hostkey %s index %d", sshkey_ssh_name(pubkey), keyid); 746 sshkey_free(pubkey); 747 748 /* 749 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 750 * SHA384 (48 bytes) and SHA512 (64 bytes). 751 * 752 * Otherwise, verify the signature request is for a hostkey 753 * proof. 754 * 755 * XXX perform similar check for KEX signature requests too? 756 * it's not trivial, since what is signed is the hash, rather 757 * than the full kex structure... 758 */ 759 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 760 /* 761 * Construct expected hostkey proof and compare it to what 762 * the client sent us. 763 */ 764 if (session_id2_len == 0) /* hostkeys is never first */ 765 fatal_f("bad data length: %zu", datlen); 766 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 767 fatal_f("no hostkey for index %d", keyid); 768 if ((sigbuf = sshbuf_new()) == NULL) 769 fatal_f("sshbuf_new"); 770 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 771 (r = sshbuf_put_string(sigbuf, session_id2, 772 session_id2_len)) != 0 || 773 (r = sshkey_puts(key, sigbuf)) != 0) 774 fatal_fr(r, "assemble private key proof"); 775 if (datlen != sshbuf_len(sigbuf) || 776 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 777 fatal_f("bad data length: %zu, hostkey proof len %zu", 778 datlen, sshbuf_len(sigbuf)); 779 sshbuf_free(sigbuf); 780 is_proof = 1; 781 } 782 783 /* save session id, it will be passed on the first call */ 784 if (session_id2_len == 0) { 785 session_id2_len = datlen; 786 session_id2 = xmalloc(session_id2_len); 787 memcpy(session_id2, p, session_id2_len); 788 } 789 790 if ((key = get_hostkey_by_index(keyid)) != NULL) { 791 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 792 options.sk_provider, NULL, compat)) != 0) 793 fatal_fr(r, "sign"); 794 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 795 auth_sock > 0) { 796 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 797 p, datlen, alg, compat)) != 0) 798 fatal_fr(r, "agent sign"); 799 } else 800 fatal_f("no hostkey from index %d", keyid); 801 802 debug3_f("%s %s signature len=%zu", alg, 803 is_proof ? "hostkey proof" : "KEX", siglen); 804 805 sshbuf_reset(m); 806 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 807 fatal_fr(r, "assemble"); 808 809 free(alg); 810 free(p); 811 free(signature); 812 813 mm_request_send(sock, MONITOR_ANS_SIGN, m); 814 815 /* Turn on permissions for getpwnam */ 816 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 817 818 return (0); 819 } 820 821 #define PUTPW(b, id) \ 822 do { \ 823 if ((r = sshbuf_put_string(b, \ 824 &pwent->id, sizeof(pwent->id))) != 0) \ 825 fatal_fr(r, "assemble %s", #id); \ 826 } while (0) 827 828 void 829 mm_encode_server_options(struct sshbuf *m) 830 { 831 int r; 832 u_int i; 833 834 /* XXX this leaks raw pointers to the unpriv child processes */ 835 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0) 836 fatal_fr(r, "assemble options"); 837 838 #define M_CP_STROPT(x) do { \ 839 if (options.x != NULL && \ 840 (r = sshbuf_put_cstring(m, options.x)) != 0) \ 841 fatal_fr(r, "assemble %s", #x); \ 842 } while (0) 843 #define M_CP_STRARRAYOPT(x, nx, clobber) do { \ 844 for (i = 0; i < options.nx; i++) { \ 845 if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \ 846 fatal_fr(r, "assemble %s", #x); \ 847 } \ 848 } while (0) 849 /* See comment in servconf.h */ 850 COPY_MATCH_STRING_OPTS(); 851 #undef M_CP_STROPT 852 #undef M_CP_STRARRAYOPT 853 } 854 855 /* Retrieves the password entry and also checks if the user is permitted */ 856 int 857 mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m) 858 { 859 struct passwd *pwent; 860 int r, allowed = 0; 861 862 debug3_f("entering"); 863 864 /* Make sure the unpriv process sent the compat bits already */ 865 if (!compat_set) 866 fatal_f("state error: setcompat never called"); 867 868 if (authctxt->attempt++ != 0) 869 fatal_f("multiple attempts for getpwnam"); 870 871 if ((r = sshbuf_get_cstring(m, &authctxt->user, NULL)) != 0) 872 fatal_fr(r, "parse"); 873 874 pwent = getpwnamallow(ssh, authctxt->user); 875 876 setproctitle("%s [priv]", pwent ? authctxt->user : "unknown"); 877 878 sshbuf_reset(m); 879 880 if (pwent == NULL) { 881 invalid_user = 1; 882 if ((r = sshbuf_put_u8(m, 0)) != 0) 883 fatal_fr(r, "assemble fakepw"); 884 authctxt->pw = fakepw(); 885 goto out; 886 } 887 888 allowed = 1; 889 authctxt->pw = pwent; 890 authctxt->valid = 1; 891 892 /* XXX send fake class/dir/shell, etc. */ 893 if ((r = sshbuf_put_u8(m, 1)) != 0) 894 fatal_fr(r, "assemble ok"); 895 PUTPW(m, pw_uid); 896 PUTPW(m, pw_gid); 897 PUTPW(m, pw_change); 898 PUTPW(m, pw_expire); 899 if ((r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || 900 (r = sshbuf_put_cstring(m, "*")) != 0 || 901 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 || 902 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 || 903 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 || 904 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0) 905 fatal_fr(r, "assemble pw"); 906 907 out: 908 ssh_packet_set_log_preamble(ssh, "%suser %s", 909 authctxt->valid ? "authenticating" : "invalid ", authctxt->user); 910 911 if (options.refuse_connection) { 912 logit("administratively prohibited connection for " 913 "%s%s from %.128s port %d", 914 authctxt->valid ? "" : "invalid user ", 915 authctxt->user, ssh_remote_ipaddr(ssh), 916 ssh_remote_port(ssh)); 917 cleanup_exit(EXIT_CONFIG_REFUSED); 918 } 919 920 /* Send active options to unpriv */ 921 mm_encode_server_options(m); 922 923 /* Create valid auth method lists */ 924 if (auth2_setup_methods_lists(authctxt) != 0) { 925 /* 926 * The monitor will continue long enough to let the child 927 * run to its packet_disconnect(), but it must not allow any 928 * authentication to succeed. 929 */ 930 debug_f("no valid authentication method lists"); 931 } 932 933 debug3_f("sending MONITOR_ANS_PWNAM: %d", allowed); 934 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 935 936 /* Allow service/style information on the auth context */ 937 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 938 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 939 940 #ifdef USE_PAM 941 if (options.use_pam) 942 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); 943 #endif 944 945 return (0); 946 } 947 948 int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m) 949 { 950 char *banner; 951 int r; 952 953 sshbuf_reset(m); 954 banner = auth2_read_banner(); 955 if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0) 956 fatal_fr(r, "assemble"); 957 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 958 free(banner); 959 960 return (0); 961 } 962 963 int 964 mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m) 965 { 966 int r; 967 968 monitor_permit_authentications(1); 969 970 if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 || 971 (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0) 972 fatal_fr(r, "parse"); 973 debug3_f("service=%s, style=%s", authctxt->service, authctxt->style); 974 975 if (strlen(authctxt->style) == 0) { 976 free(authctxt->style); 977 authctxt->style = NULL; 978 } 979 980 return (0); 981 } 982 983 int 984 mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m) 985 { 986 static int call_count; 987 char *passwd; 988 int r, authenticated; 989 size_t plen; 990 991 if (!options.password_authentication) 992 fatal_f("password authentication not enabled"); 993 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0) 994 fatal_fr(r, "parse"); 995 /* Only authenticate if the context is valid */ 996 authenticated = options.password_authentication && 997 auth_password(ssh, passwd); 998 freezero(passwd, plen); 999 1000 sshbuf_reset(m); 1001 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 1002 fatal_fr(r, "assemble"); 1003 #ifdef USE_PAM 1004 if ((r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0) 1005 fatal_fr(r, "assemble PAM"); 1006 #endif 1007 debug3_f("sending result %d", authenticated); 1008 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 1009 1010 call_count++; 1011 if (plen == 0 && call_count == 1) 1012 auth_method = "none"; 1013 else 1014 auth_method = "password"; 1015 1016 /* Causes monitor loop to terminate if authenticated */ 1017 return (authenticated); 1018 } 1019 1020 #ifdef BSD_AUTH 1021 int 1022 mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m) 1023 { 1024 char *name, *infotxt; 1025 u_int numprompts, *echo_on, success; 1026 char **prompts; 1027 int r; 1028 1029 if (!options.kbd_interactive_authentication) 1030 fatal_f("kbd-int authentication not enabled"); 1031 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 1032 &prompts, &echo_on) < 0 ? 0 : 1; 1033 1034 sshbuf_reset(m); 1035 if ((r = sshbuf_put_u32(m, success)) != 0) 1036 fatal_fr(r, "assemble"); 1037 if (success) { 1038 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0) 1039 fatal_fr(r, "assemble prompt"); 1040 } 1041 1042 debug3_f("sending challenge success: %u", success); 1043 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 1044 1045 if (success) { 1046 free(name); 1047 free(infotxt); 1048 free(prompts); 1049 free(echo_on); 1050 } 1051 1052 return (0); 1053 } 1054 1055 int 1056 mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m) 1057 { 1058 char *response; 1059 int r, authok; 1060 1061 if (!options.kbd_interactive_authentication) 1062 fatal_f("kbd-int authentication not enabled"); 1063 if (authctxt->as == NULL) 1064 fatal_f("no bsd auth session"); 1065 1066 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 1067 fatal_fr(r, "parse"); 1068 authok = options.kbd_interactive_authentication && 1069 auth_userresponse(authctxt->as, response, 0); 1070 authctxt->as = NULL; 1071 debug3_f("<%s> = <%d>", response, authok); 1072 free(response); 1073 1074 sshbuf_reset(m); 1075 if ((r = sshbuf_put_u32(m, authok)) != 0) 1076 fatal_fr(r, "assemble"); 1077 1078 debug3_f("sending authenticated: %d", authok); 1079 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 1080 1081 auth_method = "keyboard-interactive"; 1082 auth_submethod = "bsdauth"; 1083 1084 return (authok != 0); 1085 } 1086 #endif 1087 1088 #ifdef SKEY 1089 int 1090 mm_answer_skeyquery(int sock, struct sshbuf *m) 1091 { 1092 struct skey skey; 1093 char challenge[1024]; 1094 u_int success; 1095 1096 success = skeychallenge(&skey, authctxt->user, challenge, 1097 sizeof(challenge)) < 0 ? 0 : 1; 1098 1099 sshbuf_reset(m); 1100 sshbuf_put_int(m, success); 1101 if (success) 1102 sshbuf_put_cstring(m, challenge); 1103 1104 debug3("%s: sending challenge success: %u", __func__, success); 1105 mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m); 1106 1107 return (0); 1108 } 1109 1110 int 1111 mm_answer_skeyrespond(int sock, struct sshbuf *m) 1112 { 1113 char *response; 1114 int authok; 1115 int r; 1116 1117 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 1118 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1119 1120 authok = (options.kbd_interactive_authentication && 1121 authctxt->valid && 1122 skey_haskey(authctxt->pw->pw_name) == 0 && 1123 skey_passcheck(authctxt->pw->pw_name, response) != -1); 1124 1125 free(response); 1126 1127 sshbuf_reset(m); 1128 sshbuf_put_int(m, authok); 1129 1130 debug3("%s: sending authenticated: %d", __func__, authok); 1131 mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m); 1132 1133 auth_method = "skey"; 1134 auth_submethod = "bsdauth"; 1135 1136 return (authok != 0); 1137 } 1138 #endif 1139 1140 #ifdef USE_PAM 1141 int 1142 mm_answer_pam_start(struct ssh *ssh, int sock, struct sshbuf *m) 1143 { 1144 if (!options.use_pam) 1145 fatal("UsePAM not set, but ended up in %s anyway", __func__); 1146 1147 start_pam(ssh); 1148 1149 if (options.kbd_interactive_authentication) 1150 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); 1151 1152 return (0); 1153 } 1154 1155 int 1156 mm_answer_pam_account(struct ssh *ssh, int sock, struct sshbuf *m) 1157 { 1158 u_int ret; 1159 int r; 1160 1161 if (!options.use_pam) 1162 fatal("UsePAM not set, but ended up in %s anyway", __func__); 1163 1164 ret = do_pam_account(); 1165 1166 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1167 (r = sshbuf_put_stringb(m, loginmsg)) != 0) 1168 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1169 1170 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m); 1171 1172 return (ret); 1173 } 1174 1175 static void *sshpam_ctxt, *sshpam_authok; 1176 extern KbdintDevice sshpam_device; 1177 1178 int 1179 mm_answer_pam_init_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1180 { 1181 u_int ok = 0; 1182 int r; 1183 1184 debug3("%s", __func__); 1185 if (!options.kbd_interactive_authentication) 1186 fatal("%s: kbd-int authentication not enabled", __func__); 1187 if (sshpam_ctxt != NULL) 1188 fatal("%s: already called", __func__); 1189 sshpam_ctxt = (sshpam_device.init_ctx)(ssh->authctxt); 1190 sshpam_authok = NULL; 1191 sshbuf_reset(m); 1192 if (sshpam_ctxt != NULL) { 1193 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 1194 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_QUERY, 1); 1195 ok = 1; 1196 } 1197 if ((r = sshbuf_put_u32(m, ok)) != 0) 1198 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1199 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); 1200 return (0); 1201 } 1202 1203 int 1204 mm_answer_pam_query(struct ssh *ssh, int sock, struct sshbuf *m) 1205 { 1206 char *name, *info, **prompts; 1207 u_int i, num, *echo_on; 1208 int r, ret; 1209 1210 debug3("%s", __func__); 1211 sshpam_authok = NULL; 1212 if (sshpam_ctxt == NULL) 1213 fatal("%s: no context", __func__); 1214 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, 1215 &num, &prompts, &echo_on); 1216 if (ret == 0 && num == 0) 1217 sshpam_authok = sshpam_ctxt; 1218 if (num > 1 || name == NULL || info == NULL) 1219 fatal("sshpam_device.query failed"); 1220 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_RESPOND, 1); 1221 sshbuf_reset(m); 1222 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1223 (r = sshbuf_put_cstring(m, name)) != 0 || 1224 (r = sshbuf_put_cstring(m, info)) != 0 || 1225 (r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0 || 1226 (r = sshbuf_put_u32(m, num)) != 0) 1227 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1228 free(name); 1229 free(info); 1230 for (i = 0; i < num; ++i) { 1231 if ((r = sshbuf_put_cstring(m, prompts[i])) != 0 || 1232 (r = sshbuf_put_u32(m, echo_on[i])) != 0) 1233 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1234 free(prompts[i]); 1235 } 1236 free(prompts); 1237 free(echo_on); 1238 auth_method = "keyboard-interactive/pam"; 1239 auth_submethod = "pam"; 1240 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m); 1241 return (0); 1242 } 1243 1244 int 1245 mm_answer_pam_respond(struct ssh *ssh, int sock, struct sshbuf *m) 1246 { 1247 char **resp; 1248 u_int i, num; 1249 int r, ret; 1250 1251 debug3("%s", __func__); 1252 if (sshpam_ctxt == NULL) 1253 fatal("%s: no context", __func__); 1254 sshpam_authok = NULL; 1255 if ((r = sshbuf_get_u32(m, &num)) != 0) 1256 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1257 if (num > PAM_MAX_NUM_MSG) { 1258 fatal_f("Too many PAM messages, got %u, expected <= %u", 1259 num, (unsigned)PAM_MAX_NUM_MSG); 1260 } 1261 if (num > 0) { 1262 resp = xmalloc(num * sizeof(char *)); 1263 for (i = 0; i < num; ++i) 1264 if ((r = sshbuf_get_cstring(m, &resp[i], NULL)) != 0) 1265 fatal("%s: buffer error: %s", __func__, 1266 ssh_err(r)); 1267 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp); 1268 for (i = 0; i < num; ++i) 1269 free(resp[i]); 1270 free(resp); 1271 } else { 1272 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL); 1273 } 1274 sshbuf_reset(m); 1275 if ((r = sshbuf_put_u32(m, ret)) != 0) 1276 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1277 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m); 1278 auth_method = "keyboard-interactive/pam"; 1279 auth_submethod = "pam"; 1280 if (ret == 0) 1281 sshpam_authok = sshpam_ctxt; 1282 return (0); 1283 } 1284 1285 int 1286 mm_answer_pam_free_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1287 { 1288 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt; 1289 1290 debug3("%s", __func__); 1291 if (sshpam_ctxt == NULL) 1292 fatal("%s: no context", __func__); 1293 (sshpam_device.free_ctx)(sshpam_ctxt); 1294 sshpam_ctxt = sshpam_authok = NULL; 1295 sshbuf_reset(m); 1296 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); 1297 /* Allow another attempt */ 1298 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 1299 auth_method = "keyboard-interactive/pam"; 1300 auth_submethod = "pam"; 1301 return r; 1302 } 1303 #endif 1304 1305 /* 1306 * Check that the key type appears in the supplied pattern list, ignoring 1307 * mismatches in the signature algorithm. (Signature algorithm checks are 1308 * performed in the unprivileged authentication code). 1309 * Returns 1 on success, 0 otherwise. 1310 */ 1311 static int 1312 key_base_type_match(const char *method, const struct sshkey *key, 1313 const char *list) 1314 { 1315 char *s, *l, *ol = xstrdup(list); 1316 int found = 0; 1317 1318 l = ol; 1319 for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) { 1320 if (sshkey_type_from_name(s) == key->type) { 1321 found = 1; 1322 break; 1323 } 1324 } 1325 if (!found) { 1326 error("%s key type %s is not in permitted list %s", method, 1327 sshkey_ssh_name(key), list); 1328 } 1329 1330 free(ol); 1331 return found; 1332 } 1333 1334 int 1335 mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m) 1336 { 1337 struct sshkey *key = NULL; 1338 char *cuser, *chost; 1339 u_int pubkey_auth_attempt; 1340 u_int type = 0; 1341 int r, allowed = 0; 1342 struct sshauthopt *opts = NULL; 1343 1344 debug3_f("entering"); 1345 if ((r = sshbuf_get_u32(m, &type)) != 0 || 1346 (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 || 1347 (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 || 1348 (r = sshkey_froms(m, &key)) != 0 || 1349 (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0) 1350 fatal_fr(r, "parse"); 1351 1352 if (key != NULL && authctxt->valid) { 1353 switch (type) { 1354 case MM_USERKEY: 1355 auth_method = "publickey"; 1356 if (!options.pubkey_authentication) 1357 break; 1358 if (auth2_key_already_used(authctxt, key)) 1359 break; 1360 if (!key_base_type_match(auth_method, key, 1361 options.pubkey_accepted_algos)) 1362 break; 1363 allowed = user_key_allowed(ssh, authctxt->pw, key, 1364 pubkey_auth_attempt, &opts); 1365 break; 1366 case MM_HOSTKEY: 1367 auth_method = "hostbased"; 1368 if (!options.hostbased_authentication) 1369 break; 1370 if (auth2_key_already_used(authctxt, key)) 1371 break; 1372 if (!key_base_type_match(auth_method, key, 1373 options.hostbased_accepted_algos)) 1374 break; 1375 allowed = hostbased_key_allowed(ssh, authctxt->pw, 1376 cuser, chost, key); 1377 auth2_record_info(authctxt, 1378 "client user \"%.100s\", client host \"%.100s\"", 1379 cuser, chost); 1380 break; 1381 default: 1382 fatal_f("unknown key type %u", type); 1383 break; 1384 } 1385 } 1386 1387 debug3_f("%s authentication%s: %s key is %s", auth_method, 1388 pubkey_auth_attempt ? "" : " test", 1389 (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key), 1390 allowed ? "allowed" : "not allowed"); 1391 1392 auth2_record_key(authctxt, 0, key); 1393 1394 /* clear temporarily storage (used by verify) */ 1395 monitor_reset_key_state(); 1396 1397 if (allowed) { 1398 /* Save temporarily for comparison in verify */ 1399 if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0) 1400 fatal_fr(r, "sshkey_to_blob"); 1401 key_blobtype = type; 1402 key_opts = opts; 1403 hostbased_cuser = cuser; 1404 hostbased_chost = chost; 1405 } else { 1406 /* Log failed attempt */ 1407 auth_log(ssh, 0, 0, auth_method, NULL); 1408 free(cuser); 1409 free(chost); 1410 } 1411 sshkey_free(key); 1412 1413 sshbuf_reset(m); 1414 if ((r = sshbuf_put_u32(m, allowed)) != 0) 1415 fatal_fr(r, "assemble"); 1416 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0) 1417 fatal_fr(r, "sshauthopt_serialise"); 1418 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 1419 1420 if (!allowed) 1421 sshauthopt_free(opts); 1422 1423 return (0); 1424 } 1425 1426 static int 1427 monitor_valid_userblob(struct ssh *ssh, const u_char *data, u_int datalen) 1428 { 1429 struct sshbuf *b; 1430 struct sshkey *hostkey = NULL; 1431 const u_char *p; 1432 char *userstyle, *cp; 1433 size_t len; 1434 u_char type; 1435 int hostbound = 0, r, fail = 0; 1436 1437 if ((b = sshbuf_from(data, datalen)) == NULL) 1438 fatal_f("sshbuf_from"); 1439 1440 if (ssh->compat & SSH_OLD_SESSIONID) { 1441 p = sshbuf_ptr(b); 1442 len = sshbuf_len(b); 1443 if ((session_id2 == NULL) || 1444 (len < session_id2_len) || 1445 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1446 fail++; 1447 if ((r = sshbuf_consume(b, session_id2_len)) != 0) 1448 fatal_fr(r, "consume"); 1449 } else { 1450 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1451 fatal_fr(r, "parse sessionid"); 1452 if ((session_id2 == NULL) || 1453 (len != session_id2_len) || 1454 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1455 fail++; 1456 } 1457 if ((r = sshbuf_get_u8(b, &type)) != 0) 1458 fatal_fr(r, "parse type"); 1459 if (type != SSH2_MSG_USERAUTH_REQUEST) 1460 fail++; 1461 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1462 fatal_fr(r, "parse userstyle"); 1463 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1464 authctxt->style ? ":" : "", 1465 authctxt->style ? authctxt->style : ""); 1466 if (strcmp(userstyle, cp) != 0) { 1467 logit("wrong user name passed to monitor: " 1468 "expected %s != %.100s", userstyle, cp); 1469 fail++; 1470 } 1471 free(userstyle); 1472 free(cp); 1473 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1474 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1475 fatal_fr(r, "parse method"); 1476 if (strcmp("publickey", cp) != 0) { 1477 if (strcmp("publickey-hostbound-v00 (at) openssh.com", cp) == 0) 1478 hostbound = 1; 1479 else 1480 fail++; 1481 } 1482 free(cp); 1483 if ((r = sshbuf_get_u8(b, &type)) != 0) 1484 fatal_fr(r, "parse pktype"); 1485 if (type == 0) 1486 fail++; 1487 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1488 (r = sshbuf_skip_string(b)) != 0 || /* pkblob */ 1489 (hostbound && (r = sshkey_froms(b, &hostkey)) != 0)) 1490 fatal_fr(r, "parse pk"); 1491 if (sshbuf_len(b) != 0) 1492 fail++; 1493 sshbuf_free(b); 1494 if (hostkey != NULL) { 1495 /* 1496 * Ensure this is actually one of our hostkeys; unfortunately 1497 * can't check ssh->kex->initial_hostkey directly at this point 1498 * as packet state has not yet been exported to monitor. 1499 */ 1500 if (get_hostkey_index(hostkey, 1, ssh) == -1) 1501 fatal_f("hostbound hostkey does not match"); 1502 sshkey_free(hostkey); 1503 } 1504 return (fail == 0); 1505 } 1506 1507 static int 1508 monitor_valid_hostbasedblob(struct ssh *ssh, const u_char *data, u_int datalen, 1509 const char *cuser, const char *chost) 1510 { 1511 struct sshbuf *b; 1512 const u_char *p; 1513 char *cp, *userstyle; 1514 size_t len; 1515 int r, fail = 0; 1516 u_char type; 1517 1518 if ((b = sshbuf_from(data, datalen)) == NULL) 1519 fatal_f("sshbuf_new"); 1520 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1521 fatal_fr(r, "parse sessionid"); 1522 1523 if ((session_id2 == NULL) || 1524 (len != session_id2_len) || 1525 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1526 fail++; 1527 1528 if ((r = sshbuf_get_u8(b, &type)) != 0) 1529 fatal_fr(r, "parse type"); 1530 if (type != SSH2_MSG_USERAUTH_REQUEST) 1531 fail++; 1532 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1533 fatal_fr(r, "parse userstyle"); 1534 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1535 authctxt->style ? ":" : "", 1536 authctxt->style ? authctxt->style : ""); 1537 if (strcmp(userstyle, cp) != 0) { 1538 logit("wrong user name passed to monitor: " 1539 "expected %s != %.100s", userstyle, cp); 1540 fail++; 1541 } 1542 free(userstyle); 1543 free(cp); 1544 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1545 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1546 fatal_fr(r, "parse method"); 1547 if (strcmp(cp, "hostbased") != 0) 1548 fail++; 1549 free(cp); 1550 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1551 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1552 fatal_fr(r, "parse pk"); 1553 1554 /* verify client host, strip trailing dot if necessary */ 1555 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1556 fatal_fr(r, "parse host"); 1557 if (((len = strlen(cp)) > 0) && cp[len - 1] == '.') 1558 cp[len - 1] = '\0'; 1559 if (strcmp(cp, chost) != 0) 1560 fail++; 1561 free(cp); 1562 1563 /* verify client user */ 1564 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1565 fatal_fr(r, "parse ruser"); 1566 if (strcmp(cp, cuser) != 0) 1567 fail++; 1568 free(cp); 1569 1570 if (sshbuf_len(b) != 0) 1571 fail++; 1572 sshbuf_free(b); 1573 return (fail == 0); 1574 } 1575 1576 int 1577 mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m) 1578 { 1579 struct sshkey *key; 1580 const u_char *signature, *data, *blob; 1581 char *sigalg = NULL, *fp = NULL; 1582 size_t signaturelen, datalen, bloblen; 1583 int r, ret, req_presence = 0, req_verify = 0, valid_data = 0; 1584 int encoded_ret; 1585 struct sshkey_sig_details *sig_details = NULL; 1586 1587 if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 || 1588 (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 || 1589 (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 || 1590 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0) 1591 fatal_fr(r, "parse"); 1592 1593 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1594 !monitor_allowed_key(blob, bloblen)) 1595 fatal_f("bad key, not previously allowed"); 1596 1597 /* Empty signature algorithm means NULL. */ 1598 if (*sigalg == '\0') { 1599 free(sigalg); 1600 sigalg = NULL; 1601 } 1602 1603 /* XXX use sshkey_froms here; need to change key_blob, etc. */ 1604 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0) 1605 fatal_fr(r, "parse key"); 1606 1607 switch (key_blobtype) { 1608 case MM_USERKEY: 1609 valid_data = monitor_valid_userblob(ssh, data, datalen); 1610 auth_method = "publickey"; 1611 break; 1612 case MM_HOSTKEY: 1613 valid_data = monitor_valid_hostbasedblob(ssh, data, datalen, 1614 hostbased_cuser, hostbased_chost); 1615 auth_method = "hostbased"; 1616 break; 1617 default: 1618 valid_data = 0; 1619 break; 1620 } 1621 if (!valid_data) 1622 fatal_f("bad %s signature data blob", 1623 key_blobtype == MM_USERKEY ? "userkey" : 1624 (key_blobtype == MM_HOSTKEY ? "hostkey" : "unknown")); 1625 1626 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 1627 SSH_FP_DEFAULT)) == NULL) 1628 fatal_f("sshkey_fingerprint failed"); 1629 1630 ret = sshkey_verify(key, signature, signaturelen, data, datalen, 1631 sigalg, ssh->compat, &sig_details); 1632 debug3_f("%s %s signature using %s %s%s%s", auth_method, 1633 sshkey_type(key), sigalg == NULL ? "default" : sigalg, 1634 (ret == 0) ? "verified" : "unverified", 1635 (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : ""); 1636 1637 if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) { 1638 req_presence = (options.pubkey_auth_options & 1639 PUBKEYAUTH_TOUCH_REQUIRED) || 1640 !key_opts->no_require_user_presence; 1641 if (req_presence && 1642 (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) { 1643 error("public key %s %s signature for %s%s from %.128s " 1644 "port %d rejected: user presence " 1645 "(authenticator touch) requirement not met ", 1646 sshkey_type(key), fp, 1647 authctxt->valid ? "" : "invalid user ", 1648 authctxt->user, ssh_remote_ipaddr(ssh), 1649 ssh_remote_port(ssh)); 1650 ret = SSH_ERR_SIGNATURE_INVALID; 1651 } 1652 req_verify = (options.pubkey_auth_options & 1653 PUBKEYAUTH_VERIFY_REQUIRED) || key_opts->require_verify; 1654 if (req_verify && 1655 (sig_details->sk_flags & SSH_SK_USER_VERIFICATION_REQD) == 0) { 1656 error("public key %s %s signature for %s%s from %.128s " 1657 "port %d rejected: user verification requirement " 1658 "not met ", sshkey_type(key), fp, 1659 authctxt->valid ? "" : "invalid user ", 1660 authctxt->user, ssh_remote_ipaddr(ssh), 1661 ssh_remote_port(ssh)); 1662 ret = SSH_ERR_SIGNATURE_INVALID; 1663 } 1664 } 1665 auth2_record_key(authctxt, ret == 0, key); 1666 1667 if (key_blobtype == MM_USERKEY && ret == 0) 1668 auth_activate_options(ssh, key_opts); 1669 monitor_reset_key_state(); 1670 1671 sshbuf_reset(m); 1672 1673 /* encode ret != 0 as positive integer, since we're sending u32 */ 1674 encoded_ret = (ret != 0); 1675 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 || 1676 (r = sshbuf_put_u8(m, sig_details != NULL)) != 0) 1677 fatal_fr(r, "assemble"); 1678 if (sig_details != NULL) { 1679 if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 || 1680 (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0) 1681 fatal_fr(r, "assemble sk"); 1682 } 1683 sshkey_sig_details_free(sig_details); 1684 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1685 1686 free(sigalg); 1687 free(fp); 1688 sshkey_free(key); 1689 1690 return ret == 0; 1691 } 1692 1693 static void 1694 mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw) 1695 { 1696 socklen_t fromlen; 1697 struct sockaddr_storage from; 1698 1699 /* 1700 * Get IP address of client. If the connection is not a socket, let 1701 * the address be 0.0.0.0. 1702 */ 1703 memset(&from, 0, sizeof(from)); 1704 fromlen = sizeof(from); 1705 if (ssh_packet_connection_is_on_socket(ssh)) { 1706 if (getpeername(ssh_packet_get_connection_in(ssh), 1707 (struct sockaddr *)&from, &fromlen) == -1) { 1708 debug("getpeername: %.100s", strerror(errno)); 1709 cleanup_exit(255); 1710 } 1711 } 1712 /* Record that there was a login on that tty from the remote host. */ 1713 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1714 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1715 (struct sockaddr *)&from, fromlen); 1716 } 1717 1718 static void 1719 mm_session_close(Session *s) 1720 { 1721 debug3_f("session %d pid %ld", s->self, (long)s->pid); 1722 if (s->ttyfd != -1) { 1723 debug3_f("tty %s ptyfd %d", s->tty, s->ptyfd); 1724 session_pty_cleanup2(s); 1725 } 1726 session_unused(s->self); 1727 } 1728 1729 int 1730 mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m) 1731 { 1732 extern struct monitor *pmonitor; 1733 Session *s; 1734 int r, res, fd0; 1735 1736 debug3_f("entering"); 1737 1738 sshbuf_reset(m); 1739 s = session_new(); 1740 if (s == NULL) 1741 goto error; 1742 s->authctxt = authctxt; 1743 s->pw = authctxt->pw; 1744 s->pid = pmonitor->m_pid; 1745 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1746 if (res == 0) 1747 goto error; 1748 pty_setowner(authctxt->pw, s->tty); 1749 1750 if ((r = sshbuf_put_u32(m, 1)) != 0 || 1751 (r = sshbuf_put_cstring(m, s->tty)) != 0) 1752 fatal_fr(r, "assemble"); 1753 1754 /* We need to trick ttyslot */ 1755 if (dup2(s->ttyfd, 0) == -1) 1756 fatal_f("dup2"); 1757 1758 mm_record_login(ssh, s, authctxt->pw); 1759 1760 /* Now we can close the file descriptor again */ 1761 close(0); 1762 1763 /* send messages generated by record_login */ 1764 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0) 1765 fatal_fr(r, "assemble loginmsg"); 1766 sshbuf_reset(loginmsg); 1767 1768 mm_request_send(sock, MONITOR_ANS_PTY, m); 1769 1770 if (mm_send_fd(sock, s->ptyfd) == -1 || 1771 mm_send_fd(sock, s->ttyfd) == -1) 1772 fatal_f("send fds failed"); 1773 1774 /* make sure nothing uses fd 0 */ 1775 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1776 fatal_f("open(/dev/null): %s", strerror(errno)); 1777 if (fd0 != 0) 1778 error_f("fd0 %d != 0", fd0); 1779 1780 /* slave side of pty is not needed */ 1781 close(s->ttyfd); 1782 s->ttyfd = s->ptyfd; 1783 /* no need to dup() because nobody closes ptyfd */ 1784 s->ptymaster = s->ptyfd; 1785 1786 debug3_f("tty %s ptyfd %d", s->tty, s->ttyfd); 1787 1788 return (0); 1789 1790 error: 1791 if (s != NULL) 1792 mm_session_close(s); 1793 if ((r = sshbuf_put_u32(m, 0)) != 0) 1794 fatal_fr(r, "assemble 0"); 1795 mm_request_send(sock, MONITOR_ANS_PTY, m); 1796 return (0); 1797 } 1798 1799 int 1800 mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m) 1801 { 1802 Session *s; 1803 char *tty; 1804 int r; 1805 1806 debug3_f("entering"); 1807 1808 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0) 1809 fatal_fr(r, "parse tty"); 1810 if ((s = session_by_tty(tty)) != NULL) 1811 mm_session_close(s); 1812 sshbuf_reset(m); 1813 free(tty); 1814 return (0); 1815 } 1816 1817 #ifdef KRB5 1818 int 1819 mm_answer_krb5(struct ssh *ssh, int xsocket, struct sshbuf *m) 1820 { 1821 krb5_data tkt, reply; 1822 char *client_user; 1823 unsigned char *data; 1824 size_t len; 1825 int r; 1826 int success; 1827 1828 /* use temporary var to avoid size issues on 64bit arch */ 1829 if ((r = sshbuf_get_string(m, &data, &len)) != 0) 1830 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1831 tkt.data = data; 1832 tkt.length = len; 1833 1834 success = options.kerberos_authentication && 1835 authctxt->valid && 1836 auth_krb5(ssh, &tkt, &client_user, &reply); 1837 1838 if (tkt.length) 1839 free(tkt.data); 1840 1841 sshbuf_reset(m); 1842 sshbuf_put_u32(m, success); 1843 1844 if (success) { 1845 sshbuf_put_cstring(m, client_user); 1846 sshbuf_put_string(m, reply.data, reply.length); 1847 if (client_user) 1848 free(client_user); 1849 if (reply.length) 1850 free(reply.data); 1851 } 1852 mm_request_send(xsocket, MONITOR_ANS_KRB5, m); 1853 1854 auth_method = "kerberos"; 1855 1856 return success; 1857 } 1858 #endif 1859 1860 int 1861 mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req) 1862 { 1863 extern struct monitor *pmonitor; 1864 int res, status; 1865 1866 debug3_f("tearing down sessions"); 1867 1868 /* The child is terminating */ 1869 session_destroy_all(ssh, &mm_session_close); 1870 1871 #ifdef USE_PAM 1872 if (options.use_pam) 1873 sshpam_cleanup(); 1874 #endif 1875 1876 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1877 if (errno != EINTR) 1878 exit(1); 1879 1880 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1881 1882 /* Terminate process */ 1883 exit(res); 1884 } 1885 1886 void 1887 monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor) 1888 { 1889 ssh_clear_newkeys(ssh, MODE_IN); 1890 ssh_clear_newkeys(ssh, MODE_OUT); 1891 sshbuf_free(child_state); 1892 child_state = NULL; 1893 } 1894 1895 void 1896 monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor) 1897 { 1898 struct kex *kex; 1899 int r; 1900 1901 debug3_f("packet_set_state"); 1902 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1903 fatal_fr(r, "packet_set_state"); 1904 sshbuf_free(child_state); 1905 child_state = NULL; 1906 if ((kex = ssh->kex) == NULL) 1907 fatal_f("internal error: ssh->kex == NULL"); 1908 if (session_id2_len != sshbuf_len(ssh->kex->session_id)) { 1909 fatal_f("incorrect session id length %zu (expected %u)", 1910 sshbuf_len(ssh->kex->session_id), session_id2_len); 1911 } 1912 if (memcmp(sshbuf_ptr(ssh->kex->session_id), session_id2, 1913 session_id2_len) != 0) 1914 fatal_f("session ID mismatch"); 1915 /* XXX set callbacks */ 1916 #ifdef WITH_OPENSSL 1917 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server; 1918 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server; 1919 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server; 1920 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server; 1921 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server; 1922 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1923 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1924 kex->kex[KEX_ECDH_SHA2] = kex_gen_server; 1925 #endif 1926 kex->kex[KEX_C25519_SHA256] = kex_gen_server; 1927 kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server; 1928 kex->kex[KEX_KEM_MLKEM768X25519_SHA256] = kex_gen_server; 1929 kex->load_host_public_key=&get_hostkey_public_by_type; 1930 kex->load_host_private_key=&get_hostkey_private_by_type; 1931 kex->host_key_index=&get_hostkey_index; 1932 kex->sign = sshd_hostkey_sign; 1933 } 1934 1935 /* This function requires careful sanity checking */ 1936 1937 void 1938 mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor) 1939 { 1940 debug3_f("Waiting for new keys"); 1941 1942 if ((child_state = sshbuf_new()) == NULL) 1943 fatal_f("sshbuf_new failed"); 1944 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1945 child_state); 1946 debug3_f("GOT new keys"); 1947 } 1948 1949 1950 /* XXX */ 1951 1952 static void 1953 monitor_openfds(struct monitor *mon, int do_logfds) 1954 { 1955 int pair[2]; 1956 #ifdef SO_ZEROIZE 1957 int on = 1; 1958 #endif 1959 1960 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1961 fatal_f("socketpair: %s", strerror(errno)); 1962 #ifdef SO_ZEROIZE 1963 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1964 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno)); 1965 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1966 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno)); 1967 #endif 1968 FD_CLOSEONEXEC(pair[0]); 1969 FD_CLOSEONEXEC(pair[1]); 1970 mon->m_recvfd = pair[0]; 1971 mon->m_sendfd = pair[1]; 1972 1973 if (do_logfds) { 1974 if (pipe(pair) == -1) 1975 fatal_f("pipe: %s", strerror(errno)); 1976 FD_CLOSEONEXEC(pair[0]); 1977 FD_CLOSEONEXEC(pair[1]); 1978 mon->m_log_recvfd = pair[0]; 1979 mon->m_log_sendfd = pair[1]; 1980 } else 1981 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1982 } 1983 1984 struct monitor * 1985 monitor_init(void) 1986 { 1987 struct monitor *mon; 1988 1989 mon = xcalloc(1, sizeof(*mon)); 1990 monitor_openfds(mon, 1); 1991 1992 return mon; 1993 } 1994 1995 void 1996 monitor_reinit(struct monitor *mon) 1997 { 1998 monitor_openfds(mon, 0); 1999 } 2000 2001 int 2002 monitor_auth_attempted(void) 2003 { 2004 return auth_attempted; 2005 } 2006 2007 int 2008 monitor_invalid_user(void) 2009 { 2010 return invalid_user; 2011 } 2012 2013 #ifdef GSSAPI 2014 int 2015 mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 2016 { 2017 gss_OID_desc goid; 2018 OM_uint32 major; 2019 size_t len; 2020 u_char *p; 2021 int r; 2022 2023 if (!options.gss_authentication) 2024 fatal_f("GSSAPI authentication not enabled"); 2025 2026 if ((r = sshbuf_get_string(m, &p, &len)) != 0) 2027 fatal_fr(r, "parse"); 2028 goid.elements = p; 2029 goid.length = len; 2030 2031 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 2032 2033 free(goid.elements); 2034 2035 sshbuf_reset(m); 2036 if ((r = sshbuf_put_u32(m, major)) != 0) 2037 fatal_fr(r, "assemble"); 2038 2039 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 2040 2041 /* Now we have a context, enable the step */ 2042 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 2043 2044 return (0); 2045 } 2046 2047 int 2048 mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 2049 { 2050 gss_buffer_desc in; 2051 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 2052 OM_uint32 major, minor; 2053 OM_uint32 flags = 0; /* GSI needs this */ 2054 int r; 2055 2056 if (!options.gss_authentication) 2057 fatal_f("GSSAPI authentication not enabled"); 2058 2059 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0) 2060 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 2061 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 2062 free(in.value); 2063 2064 sshbuf_reset(m); 2065 if ((r = sshbuf_put_u32(m, major)) != 0 || 2066 (r = sshbuf_put_string(m, out.value, out.length)) != 0 || 2067 (r = sshbuf_put_u32(m, flags)) != 0) 2068 fatal_fr(r, "assemble"); 2069 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 2070 2071 gss_release_buffer(&minor, &out); 2072 2073 if (major == GSS_S_COMPLETE) { 2074 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 2075 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 2076 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 2077 } 2078 return (0); 2079 } 2080 2081 int 2082 mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m) 2083 { 2084 gss_buffer_desc gssbuf, mic; 2085 OM_uint32 ret; 2086 int r; 2087 2088 if (!options.gss_authentication) 2089 fatal_f("GSSAPI authentication not enabled"); 2090 2091 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 || 2092 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0) 2093 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 2094 2095 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 2096 2097 free(gssbuf.value); 2098 free(mic.value); 2099 2100 sshbuf_reset(m); 2101 if ((r = sshbuf_put_u32(m, ret)) != 0) 2102 fatal_fr(r, "assemble"); 2103 2104 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 2105 2106 if (!GSS_ERROR(ret)) 2107 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 2108 2109 return (0); 2110 } 2111 2112 int 2113 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m) 2114 { 2115 int r, authenticated; 2116 const char *displayname; 2117 2118 if (!options.gss_authentication) 2119 fatal_f("GSSAPI authentication not enabled"); 2120 2121 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 2122 2123 sshbuf_reset(m); 2124 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 2125 fatal_fr(r, "assemble"); 2126 2127 debug3_f("sending result %d", authenticated); 2128 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 2129 2130 auth_method = "gssapi-with-mic"; 2131 2132 if ((displayname = ssh_gssapi_displayname()) != NULL) 2133 auth2_record_info(authctxt, "%s", displayname); 2134 2135 /* Monitor loop will terminate if authenticated */ 2136 return (authenticated); 2137 } 2138 #endif /* GSSAPI */ 2139 2140
Indexes created Fri Jun 19 00:25:02 UTC 2026