1 /* $OpenBSD: monitor.c,v 1.236 2023/05/10 10:04:20 dtucker 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 #ifdef GSSAPI 89 #include "ssh-gss.h" 90 #endif 91 #include "monitor_wrap.h" 92 #include "monitor_fdpass.h" 93 #include "compat.h" 94 #include "ssh2.h" 95 #include "authfd.h" 96 #include "match.h" 97 #include "ssherr.h" 98 #include "sk-api.h" 99 100 #ifdef GSSAPI 101 static Gssctxt *gsscontext = NULL; 102 #endif 103 104 /* Imports */ 105 extern ServerOptions options; 106 extern u_int utmp_len; 107 extern struct sshbuf *loginmsg; 108 extern struct sshauthopt *auth_opts; /* XXX move to permanent ssh->authctxt? */ 109 110 /* State exported from the child */ 111 static struct sshbuf *child_state; 112 113 /* Functions on the monitor that answer unprivileged requests */ 114 115 int mm_answer_moduli(struct ssh *, int, struct sshbuf *); 116 int mm_answer_sign(struct ssh *, int, struct sshbuf *); 117 int mm_answer_pwnamallow(struct ssh *, int, struct sshbuf *); 118 int mm_answer_auth2_read_banner(struct ssh *, int, struct sshbuf *); 119 int mm_answer_authserv(struct ssh *, int, struct sshbuf *); 120 int mm_answer_authpassword(struct ssh *, int, struct sshbuf *); 121 int mm_answer_bsdauthquery(struct ssh *, int, struct sshbuf *); 122 int mm_answer_bsdauthrespond(struct ssh *, int, struct sshbuf *); 123 int mm_answer_keyallowed(struct ssh *, int, struct sshbuf *); 124 int mm_answer_keyverify(struct ssh *, int, struct sshbuf *); 125 int mm_answer_pty(struct ssh *, int, struct sshbuf *); 126 int mm_answer_pty_cleanup(struct ssh *, int, struct sshbuf *); 127 int mm_answer_term(struct ssh *, int, struct sshbuf *); 128 int mm_answer_sesskey(struct ssh *, int, struct sshbuf *); 129 int mm_answer_sessid(struct ssh *, int, struct sshbuf *); 130 131 #ifdef USE_PAM 132 int mm_answer_pam_start(struct ssh *, int, struct sshbuf *); 133 int mm_answer_pam_account(struct ssh *, int, struct sshbuf *); 134 int mm_answer_pam_init_ctx(struct ssh *, int, struct sshbuf *); 135 int mm_answer_pam_query(struct ssh *, int, struct sshbuf *); 136 int mm_answer_pam_respond(struct ssh *, int, struct sshbuf *); 137 int mm_answer_pam_free_ctx(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 #ifdef SSH_AUDIT_EVENTS 148 int mm_answer_audit_event(struct ssh *, int, struct sshbuf *); 149 int mm_answer_audit_command(struct ssh *, int, struct sshbuf *); 150 #endif 151 152 static Authctxt *authctxt; 153 154 /* local state for key verify */ 155 static u_char *key_blob = NULL; 156 static size_t key_bloblen = 0; 157 static u_int key_blobtype = MM_NOKEY; 158 static struct sshauthopt *key_opts = NULL; 159 static char *hostbased_cuser = NULL; 160 static char *hostbased_chost = NULL; 161 static char *auth_method = "unknown"; 162 static char *auth_submethod = NULL; 163 static u_int session_id2_len = 0; 164 static u_char *session_id2 = NULL; 165 static pid_t monitor_child_pid; 166 167 struct mon_table { 168 enum monitor_reqtype type; 169 int flags; 170 int (*f)(struct ssh *, int, struct sshbuf *); 171 }; 172 173 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 174 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 175 #define MON_ONCE 0x0010 /* Disable after calling */ 176 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 177 178 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 179 180 #define MON_PERMIT 0x1000 /* Request is permitted */ 181 182 static int monitor_read(struct ssh *, struct monitor *, struct mon_table *, 183 struct mon_table **); 184 static int monitor_read_log(struct monitor *); 185 186 struct mon_table mon_dispatch_proto20[] = { 187 #ifdef WITH_OPENSSL 188 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 189 #endif 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_ONCE, mm_answer_pam_init_ctx}, 199 {MONITOR_REQ_PAM_QUERY, 0, mm_answer_pam_query}, 200 {MONITOR_REQ_PAM_RESPOND, MON_ONCE, mm_answer_pam_respond}, 201 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 202 #endif 203 #ifdef SSH_AUDIT_EVENTS 204 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 205 #endif 206 #ifdef BSD_AUTH 207 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 208 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 209 #endif 210 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 211 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 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 #ifdef WITH_OPENSSL 223 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 224 #endif 225 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 226 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 227 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 228 {MONITOR_REQ_TERM, 0, mm_answer_term}, 229 #ifdef SSH_AUDIT_EVENTS 230 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 231 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command}, 232 #endif 233 {0, 0, NULL} 234 }; 235 236 struct mon_table *mon_dispatch; 237 238 /* Specifies if a certain message is allowed at the moment */ 239 static void 240 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 241 { 242 while (ent->f != NULL) { 243 if (ent->type == type) { 244 ent->flags &= ~MON_PERMIT; 245 ent->flags |= permit ? MON_PERMIT : 0; 246 return; 247 } 248 ent++; 249 } 250 } 251 252 static void 253 monitor_permit_authentications(int permit) 254 { 255 struct mon_table *ent = mon_dispatch; 256 257 while (ent->f != NULL) { 258 if (ent->flags & MON_AUTH) { 259 ent->flags &= ~MON_PERMIT; 260 ent->flags |= permit ? MON_PERMIT : 0; 261 } 262 ent++; 263 } 264 } 265 266 void 267 monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor) 268 { 269 struct mon_table *ent; 270 int authenticated = 0, partial = 0; 271 272 debug3("preauth child monitor started"); 273 274 if (pmonitor->m_recvfd >= 0) 275 close(pmonitor->m_recvfd); 276 if (pmonitor->m_log_sendfd >= 0) 277 close(pmonitor->m_log_sendfd); 278 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 279 280 authctxt = (Authctxt *)ssh->authctxt; 281 memset(authctxt, 0, sizeof(*authctxt)); 282 ssh->authctxt = authctxt; 283 284 authctxt->loginmsg = loginmsg; 285 286 mon_dispatch = mon_dispatch_proto20; 287 /* Permit requests for moduli and signatures */ 288 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 289 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 290 291 /* The first few requests do not require asynchronous access */ 292 while (!authenticated) { 293 partial = 0; 294 auth_method = "unknown"; 295 auth_submethod = NULL; 296 auth2_authctxt_reset_info(authctxt); 297 298 authenticated = (monitor_read(ssh, pmonitor, 299 mon_dispatch, &ent) == 1); 300 301 /* Special handling for multiple required authentications */ 302 if (options.num_auth_methods != 0) { 303 if (authenticated && 304 !auth2_update_methods_lists(authctxt, 305 auth_method, auth_submethod)) { 306 debug3_f("method %s: partial", auth_method); 307 authenticated = 0; 308 partial = 1; 309 } 310 } 311 312 if (authenticated) { 313 if (!(ent->flags & MON_AUTHDECIDE)) 314 fatal_f("unexpected authentication from %d", 315 ent->type); 316 if (authctxt->pw->pw_uid == 0 && 317 !auth_root_allowed(ssh, auth_method)) 318 authenticated = 0; 319 #ifdef USE_PAM 320 /* PAM needs to perform account checks after auth */ 321 if (options.use_pam && authenticated) { 322 struct sshbuf *m; 323 324 if ((m = sshbuf_new()) == NULL) 325 fatal("%s: sshbuf_new failed", 326 __func__); 327 mm_request_receive_expect(pmonitor->m_sendfd, 328 MONITOR_REQ_PAM_ACCOUNT, m); 329 authenticated = mm_answer_pam_account( 330 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 } 346 347 if (!authctxt->valid) 348 fatal_f("authenticated invalid user"); 349 if (strcmp(auth_method, "unknown") == 0) 350 fatal_f("authentication method name unknown"); 351 352 debug_f("user %s authenticated by privileged process", authctxt->user); 353 ssh->authctxt = NULL; 354 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 355 356 mm_get_keystate(ssh, pmonitor); 357 358 /* Drain any buffered messages from the child */ 359 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 360 ; 361 362 if (pmonitor->m_recvfd >= 0) 363 close(pmonitor->m_recvfd); 364 if (pmonitor->m_log_sendfd >= 0) 365 close(pmonitor->m_log_sendfd); 366 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 367 } 368 369 static void 370 monitor_set_child_handler(pid_t pid) 371 { 372 monitor_child_pid = pid; 373 } 374 375 static void 376 monitor_child_handler(int sig) 377 { 378 kill(monitor_child_pid, sig); 379 } 380 381 void 382 monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor) 383 { 384 close(pmonitor->m_recvfd); 385 pmonitor->m_recvfd = -1; 386 387 monitor_set_child_handler(pmonitor->m_pid); 388 ssh_signal(SIGHUP, &monitor_child_handler); 389 ssh_signal(SIGTERM, &monitor_child_handler); 390 ssh_signal(SIGINT, &monitor_child_handler); 391 #ifdef SIGXFSZ 392 ssh_signal(SIGXFSZ, SIG_IGN); 393 #endif 394 395 mon_dispatch = mon_dispatch_postauth20; 396 397 /* Permit requests for moduli and signatures */ 398 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 399 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 400 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 401 402 if (auth_opts->permit_pty_flag) { 403 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 404 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 405 } 406 407 for (;;) 408 monitor_read(ssh, pmonitor, mon_dispatch, NULL); 409 } 410 411 static int 412 monitor_read_log(struct monitor *pmonitor) 413 { 414 struct sshbuf *logmsg; 415 u_int len, level, forced; 416 char *msg; 417 u_char *p; 418 int r; 419 420 if ((logmsg = sshbuf_new()) == NULL) 421 fatal_f("sshbuf_new"); 422 423 /* Read length */ 424 if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0) 425 fatal_fr(r, "reserve len"); 426 if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) { 427 if (errno == EPIPE) { 428 sshbuf_free(logmsg); 429 debug_f("child log fd closed"); 430 close(pmonitor->m_log_recvfd); 431 pmonitor->m_log_recvfd = -1; 432 return -1; 433 } 434 fatal_f("log fd read: %s", strerror(errno)); 435 } 436 if ((r = sshbuf_get_u32(logmsg, &len)) != 0) 437 fatal_fr(r, "parse len"); 438 if (len <= 4 || len > 8192) 439 fatal_f("invalid log message length %u", len); 440 441 /* Read severity, message */ 442 sshbuf_reset(logmsg); 443 if ((r = sshbuf_reserve(logmsg, len, &p)) != 0) 444 fatal_fr(r, "reserve msg"); 445 if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len) 446 fatal_f("log fd read: %s", strerror(errno)); 447 if ((r = sshbuf_get_u32(logmsg, &level)) != 0 || 448 (r = sshbuf_get_u32(logmsg, &forced)) != 0 || 449 (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0) 450 fatal_fr(r, "parse"); 451 452 /* Log it */ 453 if (log_level_name(level) == NULL) 454 fatal_f("invalid log level %u (corrupted message?)", level); 455 sshlogdirect(level, forced, "%s [preauth]", msg); 456 457 sshbuf_free(logmsg); 458 free(msg); 459 460 return 0; 461 } 462 463 static int 464 monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent, 465 struct mon_table **pent) 466 { 467 struct sshbuf *m; 468 int r, ret; 469 u_char type; 470 struct pollfd pfd[2]; 471 472 for (;;) { 473 memset(&pfd, 0, sizeof(pfd)); 474 pfd[0].fd = pmonitor->m_sendfd; 475 pfd[0].events = POLLIN; 476 pfd[1].fd = pmonitor->m_log_recvfd; 477 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 478 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 479 if (errno == EINTR || errno == EAGAIN) 480 continue; 481 fatal_f("poll: %s", strerror(errno)); 482 } 483 if (pfd[1].revents) { 484 /* 485 * Drain all log messages before processing next 486 * monitor request. 487 */ 488 monitor_read_log(pmonitor); 489 continue; 490 } 491 if (pfd[0].revents) 492 break; /* Continues below */ 493 } 494 495 if ((m = sshbuf_new()) == NULL) 496 fatal_f("sshbuf_new"); 497 498 mm_request_receive(pmonitor->m_sendfd, m); 499 if ((r = sshbuf_get_u8(m, &type)) != 0) 500 fatal_fr(r, "parse type"); 501 502 debug3_f("checking request %d", type); 503 504 while (ent->f != NULL) { 505 if (ent->type == type) 506 break; 507 ent++; 508 } 509 510 if (ent->f != NULL) { 511 if (!(ent->flags & MON_PERMIT)) 512 fatal_f("unpermitted request %d", type); 513 ret = (*ent->f)(ssh, pmonitor->m_sendfd, m); 514 sshbuf_free(m); 515 516 /* The child may use this request only once, disable it */ 517 if (ent->flags & MON_ONCE) { 518 debug2_f("%d used once, disabling now", type); 519 ent->flags &= ~MON_PERMIT; 520 } 521 522 if (pent != NULL) 523 *pent = ent; 524 525 return ret; 526 } 527 528 fatal_f("unsupported request: %d", type); 529 530 /* NOTREACHED */ 531 return (-1); 532 } 533 534 /* allowed key state */ 535 static int 536 monitor_allowed_key(const u_char *blob, u_int bloblen) 537 { 538 /* make sure key is allowed */ 539 if (key_blob == NULL || key_bloblen != bloblen || 540 timingsafe_bcmp(key_blob, blob, key_bloblen)) 541 return (0); 542 return (1); 543 } 544 545 static void 546 monitor_reset_key_state(void) 547 { 548 /* reset state */ 549 free(key_blob); 550 free(hostbased_cuser); 551 free(hostbased_chost); 552 sshauthopt_free(key_opts); 553 key_blob = NULL; 554 key_bloblen = 0; 555 key_blobtype = MM_NOKEY; 556 key_opts = NULL; 557 hostbased_cuser = NULL; 558 hostbased_chost = NULL; 559 } 560 561 #ifdef WITH_OPENSSL 562 int 563 mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m) 564 { 565 DH *dh; 566 const BIGNUM *dh_p, *dh_g; 567 int r; 568 u_int min, want, max; 569 570 if ((r = sshbuf_get_u32(m, &min)) != 0 || 571 (r = sshbuf_get_u32(m, &want)) != 0 || 572 (r = sshbuf_get_u32(m, &max)) != 0) 573 fatal_fr(r, "parse"); 574 575 debug3_f("got parameters: %d %d %d", min, want, max); 576 /* We need to check here, too, in case the child got corrupted */ 577 if (max < min || want < min || max < want) 578 fatal_f("bad parameters: %d %d %d", min, want, max); 579 580 sshbuf_reset(m); 581 582 dh = choose_dh(min, want, max); 583 if (dh == NULL) { 584 if ((r = sshbuf_put_u8(m, 0)) != 0) 585 fatal_fr(r, "assemble empty"); 586 return (0); 587 } else { 588 /* Send first bignum */ 589 DH_get0_pqg(dh, &dh_p, NULL, &dh_g); 590 if ((r = sshbuf_put_u8(m, 1)) != 0 || 591 (r = sshbuf_put_bignum2(m, dh_p)) != 0 || 592 (r = sshbuf_put_bignum2(m, dh_g)) != 0) 593 fatal_fr(r, "assemble"); 594 595 DH_free(dh); 596 } 597 mm_request_send(sock, MONITOR_ANS_MODULI, m); 598 return (0); 599 } 600 #endif 601 602 int 603 mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m) 604 { 605 extern int auth_sock; /* XXX move to state struct? */ 606 struct sshkey *key; 607 struct sshbuf *sigbuf = NULL; 608 u_char *p = NULL, *signature = NULL; 609 char *alg = NULL; 610 size_t datlen, siglen, alglen; 611 int r, is_proof = 0; 612 u_int keyid, compat; 613 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 614 615 debug3_f("entering"); 616 617 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 618 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 619 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0 || 620 (r = sshbuf_get_u32(m, &compat)) != 0) 621 fatal_fr(r, "parse"); 622 if (keyid > INT_MAX) 623 fatal_f("invalid key ID"); 624 625 /* 626 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 627 * SHA384 (48 bytes) and SHA512 (64 bytes). 628 * 629 * Otherwise, verify the signature request is for a hostkey 630 * proof. 631 * 632 * XXX perform similar check for KEX signature requests too? 633 * it's not trivial, since what is signed is the hash, rather 634 * than the full kex structure... 635 */ 636 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 637 /* 638 * Construct expected hostkey proof and compare it to what 639 * the client sent us. 640 */ 641 if (session_id2_len == 0) /* hostkeys is never first */ 642 fatal_f("bad data length: %zu", datlen); 643 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 644 fatal_f("no hostkey for index %d", keyid); 645 if ((sigbuf = sshbuf_new()) == NULL) 646 fatal_f("sshbuf_new"); 647 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 648 (r = sshbuf_put_string(sigbuf, session_id2, 649 session_id2_len)) != 0 || 650 (r = sshkey_puts(key, sigbuf)) != 0) 651 fatal_fr(r, "assemble private key proof"); 652 if (datlen != sshbuf_len(sigbuf) || 653 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 654 fatal_f("bad data length: %zu, hostkey proof len %zu", 655 datlen, sshbuf_len(sigbuf)); 656 sshbuf_free(sigbuf); 657 is_proof = 1; 658 } 659 660 /* save session id, it will be passed on the first call */ 661 if (session_id2_len == 0) { 662 session_id2_len = datlen; 663 session_id2 = xmalloc(session_id2_len); 664 memcpy(session_id2, p, session_id2_len); 665 } 666 667 if ((key = get_hostkey_by_index(keyid)) != NULL) { 668 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 669 options.sk_provider, NULL, compat)) != 0) 670 fatal_fr(r, "sign"); 671 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 672 auth_sock > 0) { 673 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 674 p, datlen, alg, compat)) != 0) 675 fatal_fr(r, "agent sign"); 676 } else 677 fatal_f("no hostkey from index %d", keyid); 678 679 debug3_f("%s %s signature len=%zu", alg, 680 is_proof ? "hostkey proof" : "KEX", siglen); 681 682 sshbuf_reset(m); 683 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 684 fatal_fr(r, "assemble"); 685 686 free(alg); 687 free(p); 688 free(signature); 689 690 mm_request_send(sock, MONITOR_ANS_SIGN, m); 691 692 /* Turn on permissions for getpwnam */ 693 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 694 695 return (0); 696 } 697 698 #define PUTPW(b, id) \ 699 do { \ 700 if ((r = sshbuf_put_string(b, \ 701 &pwent->id, sizeof(pwent->id))) != 0) \ 702 fatal_fr(r, "assemble %s", #id); \ 703 } while (0) 704 705 /* Retrieves the password entry and also checks if the user is permitted */ 706 int 707 mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m) 708 { 709 struct passwd *pwent; 710 int r, allowed = 0; 711 u_int i; 712 713 debug3_f("entering"); 714 715 if (authctxt->attempt++ != 0) 716 fatal_f("multiple attempts for getpwnam"); 717 718 if ((r = sshbuf_get_cstring(m, &authctxt->user, NULL)) != 0) 719 fatal_fr(r, "parse"); 720 721 pwent = getpwnamallow(ssh, authctxt->user); 722 723 setproctitle("%s [priv]", pwent ? authctxt->user : "unknown"); 724 725 sshbuf_reset(m); 726 727 if (pwent == NULL) { 728 if ((r = sshbuf_put_u8(m, 0)) != 0) 729 fatal_fr(r, "assemble fakepw"); 730 authctxt->pw = fakepw(); 731 goto out; 732 } 733 734 allowed = 1; 735 authctxt->pw = pwent; 736 authctxt->valid = 1; 737 738 /* XXX send fake class/dir/shell, etc. */ 739 if ((r = sshbuf_put_u8(m, 1)) != 0) 740 fatal_fr(r, "assemble ok"); 741 PUTPW(m, pw_uid); 742 PUTPW(m, pw_gid); 743 #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE 744 PUTPW(m, pw_change); 745 #endif 746 #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE 747 PUTPW(m, pw_expire); 748 #endif 749 if ((r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || 750 (r = sshbuf_put_cstring(m, "*")) != 0 || 751 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS 752 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 || 753 #endif 754 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS 755 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 || 756 #endif 757 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 || 758 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0) 759 fatal_fr(r, "assemble pw"); 760 761 out: 762 ssh_packet_set_log_preamble(ssh, "%suser %s", 763 authctxt->valid ? "authenticating" : "invalid ", authctxt->user); 764 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0) 765 fatal_fr(r, "assemble options"); 766 767 #define M_CP_STROPT(x) do { \ 768 if (options.x != NULL && \ 769 (r = sshbuf_put_cstring(m, options.x)) != 0) \ 770 fatal_fr(r, "assemble %s", #x); \ 771 } while (0) 772 #define M_CP_STRARRAYOPT(x, nx) do { \ 773 for (i = 0; i < options.nx; i++) { \ 774 if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \ 775 fatal_fr(r, "assemble %s", #x); \ 776 } \ 777 } while (0) 778 /* See comment in servconf.h */ 779 COPY_MATCH_STRING_OPTS(); 780 #undef M_CP_STROPT 781 #undef M_CP_STRARRAYOPT 782 783 /* Create valid auth method lists */ 784 if (auth2_setup_methods_lists(authctxt) != 0) { 785 /* 786 * The monitor will continue long enough to let the child 787 * run to its packet_disconnect(), but it must not allow any 788 * authentication to succeed. 789 */ 790 debug_f("no valid authentication method lists"); 791 } 792 793 debug3_f("sending MONITOR_ANS_PWNAM: %d", allowed); 794 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 795 796 /* Allow service/style information on the auth context */ 797 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 798 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 799 800 #ifdef USE_PAM 801 if (options.use_pam) 802 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); 803 #endif 804 805 return (0); 806 } 807 808 int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m) 809 { 810 char *banner; 811 int r; 812 813 sshbuf_reset(m); 814 banner = auth2_read_banner(); 815 if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0) 816 fatal_fr(r, "assemble"); 817 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 818 free(banner); 819 820 return (0); 821 } 822 823 int 824 mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m) 825 { 826 int r; 827 828 monitor_permit_authentications(1); 829 830 if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 || 831 (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0) 832 fatal_fr(r, "parse"); 833 debug3_f("service=%s, style=%s", authctxt->service, authctxt->style); 834 835 if (strlen(authctxt->style) == 0) { 836 free(authctxt->style); 837 authctxt->style = NULL; 838 } 839 840 return (0); 841 } 842 843 /* 844 * Check that the key type appears in the supplied pattern list, ignoring 845 * mismatches in the signature algorithm. (Signature algorithm checks are 846 * performed in the unprivileged authentication code). 847 * Returns 1 on success, 0 otherwise. 848 */ 849 static int 850 key_base_type_match(const char *method, const struct sshkey *key, 851 const char *list) 852 { 853 char *s, *l, *ol = xstrdup(list); 854 int found = 0; 855 856 l = ol; 857 for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) { 858 if (sshkey_type_from_name(s) == key->type) { 859 found = 1; 860 break; 861 } 862 } 863 if (!found) { 864 error("%s key type %s is not in permitted list %s", method, 865 sshkey_ssh_name(key), list); 866 } 867 868 free(ol); 869 return found; 870 } 871 872 int 873 mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m) 874 { 875 static int call_count; 876 char *passwd; 877 int r, authenticated; 878 size_t plen; 879 880 if (!options.password_authentication) 881 fatal_f("password authentication not enabled"); 882 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0) 883 fatal_fr(r, "parse"); 884 /* Only authenticate if the context is valid */ 885 authenticated = options.password_authentication && 886 auth_password(ssh, passwd); 887 freezero(passwd, plen); 888 889 sshbuf_reset(m); 890 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 891 fatal_fr(r, "assemble"); 892 #ifdef USE_PAM 893 if ((r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0) 894 fatal_fr(r, "assemble PAM"); 895 #endif 896 897 debug3("%s: sending result %d", __func__, authenticated); 898 debug3_f("sending result %d", authenticated); 899 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 900 901 call_count++; 902 if (plen == 0 && call_count == 1) 903 auth_method = "none"; 904 else 905 auth_method = "password"; 906 907 /* Causes monitor loop to terminate if authenticated */ 908 return (authenticated); 909 } 910 911 #ifdef BSD_AUTH 912 int 913 mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m) 914 { 915 char *name, *infotxt; 916 u_int numprompts, *echo_on, success; 917 char **prompts; 918 int r; 919 920 if (!options.kbd_interactive_authentication) 921 fatal_f("kbd-int authentication not enabled"); 922 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 923 &prompts, &echo_on) < 0 ? 0 : 1; 924 925 sshbuf_reset(m); 926 if ((r = sshbuf_put_u32(m, success)) != 0) 927 fatal_fr(r, "assemble"); 928 if (success) { 929 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0) 930 fatal_fr(r, "assemble prompt"); 931 } 932 933 debug3_f("sending challenge success: %u", success); 934 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 935 936 if (success) { 937 free(name); 938 free(infotxt); 939 free(prompts); 940 free(echo_on); 941 } 942 943 return (0); 944 } 945 946 int 947 mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m) 948 { 949 char *response; 950 int r, authok; 951 952 if (!options.kbd_interactive_authentication) 953 fatal_f("kbd-int authentication not enabled"); 954 if (authctxt->as == NULL) 955 fatal_f("no bsd auth session"); 956 957 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 958 fatal_fr(r, "parse"); 959 authok = options.kbd_interactive_authentication && 960 auth_userresponse(authctxt->as, response, 0); 961 authctxt->as = NULL; 962 debug3_f("<%s> = <%d>", response, authok); 963 free(response); 964 965 sshbuf_reset(m); 966 if ((r = sshbuf_put_u32(m, authok)) != 0) 967 fatal_fr(r, "assemble"); 968 969 debug3_f("sending authenticated: %d", authok); 970 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 971 972 auth_method = "keyboard-interactive"; 973 auth_submethod = "bsdauth"; 974 975 return (authok != 0); 976 } 977 #endif 978 979 #ifdef USE_PAM 980 int 981 mm_answer_pam_start(struct ssh *ssh, int sock, struct sshbuf *m) 982 { 983 if (!options.use_pam) 984 fatal("UsePAM not set, but ended up in %s anyway", __func__); 985 986 start_pam(ssh); 987 988 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); 989 if (options.kbd_interactive_authentication) 990 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 991 992 return (0); 993 } 994 995 int 996 mm_answer_pam_account(struct ssh *ssh, int sock, struct sshbuf *m) 997 { 998 u_int ret; 999 int r; 1000 1001 if (!options.use_pam) 1002 fatal("%s: PAM not enabled", __func__); 1003 1004 ret = do_pam_account(); 1005 1006 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1007 (r = sshbuf_put_stringb(m, loginmsg)) != 0) 1008 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1009 1010 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m); 1011 1012 return (ret); 1013 } 1014 1015 static void *sshpam_ctxt, *sshpam_authok; 1016 extern KbdintDevice sshpam_device; 1017 1018 int 1019 mm_answer_pam_init_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1020 { 1021 u_int ok = 0; 1022 int r; 1023 1024 debug3("%s", __func__); 1025 if (!options.kbd_interactive_authentication) 1026 fatal("%s: kbd-int authentication not enabled", __func__); 1027 if (sshpam_ctxt != NULL) 1028 fatal("%s: already called", __func__); 1029 sshpam_ctxt = (sshpam_device.init_ctx)(authctxt); 1030 sshpam_authok = NULL; 1031 sshbuf_reset(m); 1032 if (sshpam_ctxt != NULL) { 1033 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 1034 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_QUERY, 1); 1035 ok = 1; 1036 } 1037 if ((r = sshbuf_put_u32(m, ok)) != 0) 1038 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1039 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); 1040 return (0); 1041 } 1042 1043 int 1044 mm_answer_pam_query(struct ssh *ssh, int sock, struct sshbuf *m) 1045 { 1046 char *name = NULL, *info = NULL, **prompts = NULL; 1047 u_int i, num = 0, *echo_on = 0; 1048 int r, ret; 1049 1050 debug3("%s", __func__); 1051 sshpam_authok = NULL; 1052 if (sshpam_ctxt == NULL) 1053 fatal("%s: no context", __func__); 1054 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, 1055 &num, &prompts, &echo_on); 1056 if (ret == 0 && num == 0) 1057 sshpam_authok = sshpam_ctxt; 1058 if (num > 1 || name == NULL || info == NULL) 1059 fatal("sshpam_device.query failed"); 1060 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_RESPOND, 1); 1061 sshbuf_reset(m); 1062 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1063 (r = sshbuf_put_cstring(m, name)) != 0 || 1064 (r = sshbuf_put_cstring(m, info)) != 0 || 1065 (r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0 || 1066 (r = sshbuf_put_u32(m, num)) != 0) 1067 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1068 free(name); 1069 free(info); 1070 for (i = 0; i < num; ++i) { 1071 if ((r = sshbuf_put_cstring(m, prompts[i])) != 0 || 1072 (r = sshbuf_put_u32(m, echo_on[i])) != 0) 1073 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1074 free(prompts[i]); 1075 } 1076 free(prompts); 1077 free(echo_on); 1078 auth_method = "keyboard-interactive"; 1079 auth_submethod = "pam"; 1080 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m); 1081 return (0); 1082 } 1083 1084 int 1085 mm_answer_pam_respond(struct ssh *ssh, int sock, struct sshbuf *m) 1086 { 1087 char **resp; 1088 u_int i, num; 1089 int r, ret; 1090 1091 debug3("%s", __func__); 1092 if (sshpam_ctxt == NULL) 1093 fatal("%s: no context", __func__); 1094 sshpam_authok = NULL; 1095 if ((r = sshbuf_get_u32(m, &num)) != 0) 1096 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1097 if (num > PAM_MAX_NUM_MSG) { 1098 fatal_f("Too many PAM messages, got %u, expected <= %u", 1099 num, (unsigned)PAM_MAX_NUM_MSG); 1100 } 1101 if (num > 0) { 1102 resp = xcalloc(num, sizeof(char *)); 1103 for (i = 0; i < num; ++i) { 1104 if ((r = sshbuf_get_cstring(m, &(resp[i]), NULL)) != 0) 1105 fatal("%s: buffer error: %s", 1106 __func__, ssh_err(r)); 1107 } 1108 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp); 1109 for (i = 0; i < num; ++i) 1110 free(resp[i]); 1111 free(resp); 1112 } else { 1113 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL); 1114 } 1115 sshbuf_reset(m); 1116 if ((r = sshbuf_put_u32(m, ret)) != 0) 1117 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1118 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m); 1119 auth_method = "keyboard-interactive"; 1120 auth_submethod = "pam"; 1121 if (ret == 0) 1122 sshpam_authok = sshpam_ctxt; 1123 return (0); 1124 } 1125 1126 int 1127 mm_answer_pam_free_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1128 { 1129 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt; 1130 1131 debug3("%s", __func__); 1132 if (sshpam_ctxt == NULL) 1133 fatal("%s: no context", __func__); 1134 (sshpam_device.free_ctx)(sshpam_ctxt); 1135 sshpam_ctxt = sshpam_authok = NULL; 1136 sshbuf_reset(m); 1137 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); 1138 /* Allow another attempt */ 1139 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 1140 auth_method = "keyboard-interactive"; 1141 auth_submethod = "pam"; 1142 return r; 1143 } 1144 #endif 1145 1146 int 1147 mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m) 1148 { 1149 struct sshkey *key = NULL; 1150 char *cuser, *chost; 1151 u_int pubkey_auth_attempt; 1152 u_int type = 0; 1153 int r, allowed = 0; 1154 struct sshauthopt *opts = NULL; 1155 1156 debug3_f("entering"); 1157 if ((r = sshbuf_get_u32(m, &type)) != 0 || 1158 (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 || 1159 (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 || 1160 (r = sshkey_froms(m, &key)) != 0 || 1161 (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0) 1162 fatal_fr(r, "parse"); 1163 1164 if (key != NULL && authctxt->valid) { 1165 switch (type) { 1166 case MM_USERKEY: 1167 auth_method = "publickey"; 1168 if (!options.pubkey_authentication) 1169 break; 1170 if (auth2_key_already_used(authctxt, key)) 1171 break; 1172 if (!key_base_type_match(auth_method, key, 1173 options.pubkey_accepted_algos)) 1174 break; 1175 allowed = user_key_allowed(ssh, authctxt->pw, key, 1176 pubkey_auth_attempt, &opts); 1177 break; 1178 case MM_HOSTKEY: 1179 auth_method = "hostbased"; 1180 if (!options.hostbased_authentication) 1181 break; 1182 if (auth2_key_already_used(authctxt, key)) 1183 break; 1184 if (!key_base_type_match(auth_method, key, 1185 options.hostbased_accepted_algos)) 1186 break; 1187 allowed = hostbased_key_allowed(ssh, authctxt->pw, 1188 cuser, chost, key); 1189 auth2_record_info(authctxt, 1190 "client user \"%.100s\", client host \"%.100s\"", 1191 cuser, chost); 1192 break; 1193 default: 1194 fatal_f("unknown key type %u", type); 1195 break; 1196 } 1197 } 1198 1199 debug3_f("%s authentication%s: %s key is %s", auth_method, 1200 pubkey_auth_attempt ? "" : " test", 1201 (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key), 1202 allowed ? "allowed" : "not allowed"); 1203 1204 auth2_record_key(authctxt, 0, key); 1205 1206 /* clear temporarily storage (used by verify) */ 1207 monitor_reset_key_state(); 1208 1209 if (allowed) { 1210 /* Save temporarily for comparison in verify */ 1211 if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0) 1212 fatal_fr(r, "sshkey_to_blob"); 1213 key_blobtype = type; 1214 key_opts = opts; 1215 hostbased_cuser = cuser; 1216 hostbased_chost = chost; 1217 } else { 1218 /* Log failed attempt */ 1219 auth_log(ssh, 0, 0, auth_method, NULL); 1220 free(cuser); 1221 free(chost); 1222 } 1223 sshkey_free(key); 1224 1225 sshbuf_reset(m); 1226 if ((r = sshbuf_put_u32(m, allowed)) != 0) 1227 fatal_fr(r, "assemble"); 1228 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0) 1229 fatal_fr(r, "sshauthopt_serialise"); 1230 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 1231 1232 if (!allowed) 1233 sshauthopt_free(opts); 1234 1235 return (0); 1236 } 1237 1238 static int 1239 monitor_valid_userblob(struct ssh *ssh, const u_char *data, u_int datalen) 1240 { 1241 struct sshbuf *b; 1242 struct sshkey *hostkey = NULL; 1243 const u_char *p; 1244 char *userstyle, *cp; 1245 size_t len; 1246 u_char type; 1247 int hostbound = 0, r, fail = 0; 1248 1249 if ((b = sshbuf_from(data, datalen)) == NULL) 1250 fatal_f("sshbuf_from"); 1251 1252 if (ssh->compat & SSH_OLD_SESSIONID) { 1253 p = sshbuf_ptr(b); 1254 len = sshbuf_len(b); 1255 if ((session_id2 == NULL) || 1256 (len < session_id2_len) || 1257 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1258 fail++; 1259 if ((r = sshbuf_consume(b, session_id2_len)) != 0) 1260 fatal_fr(r, "consume"); 1261 } else { 1262 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1263 fatal_fr(r, "parse sessionid"); 1264 if ((session_id2 == NULL) || 1265 (len != session_id2_len) || 1266 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1267 fail++; 1268 } 1269 if ((r = sshbuf_get_u8(b, &type)) != 0) 1270 fatal_fr(r, "parse type"); 1271 if (type != SSH2_MSG_USERAUTH_REQUEST) 1272 fail++; 1273 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1274 fatal_fr(r, "parse userstyle"); 1275 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1276 authctxt->style ? ":" : "", 1277 authctxt->style ? authctxt->style : ""); 1278 if (strcmp(userstyle, cp) != 0) { 1279 logit("wrong user name passed to monitor: " 1280 "expected %s != %.100s", userstyle, cp); 1281 fail++; 1282 } 1283 free(userstyle); 1284 free(cp); 1285 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1286 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1287 fatal_fr(r, "parse method"); 1288 if (strcmp("publickey", cp) != 0) { 1289 if (strcmp("publickey-hostbound-v00@openssh.com", cp) == 0) 1290 hostbound = 1; 1291 else 1292 fail++; 1293 } 1294 free(cp); 1295 if ((r = sshbuf_get_u8(b, &type)) != 0) 1296 fatal_fr(r, "parse pktype"); 1297 if (type == 0) 1298 fail++; 1299 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1300 (r = sshbuf_skip_string(b)) != 0 || /* pkblob */ 1301 (hostbound && (r = sshkey_froms(b, &hostkey)) != 0)) 1302 fatal_fr(r, "parse pk"); 1303 if (sshbuf_len(b) != 0) 1304 fail++; 1305 sshbuf_free(b); 1306 if (hostkey != NULL) { 1307 /* 1308 * Ensure this is actually one of our hostkeys; unfortunately 1309 * can't check ssh->kex->initial_hostkey directly at this point 1310 * as packet state has not yet been exported to monitor. 1311 */ 1312 if (get_hostkey_index(hostkey, 1, ssh) == -1) 1313 fatal_f("hostbound hostkey does not match"); 1314 sshkey_free(hostkey); 1315 } 1316 return (fail == 0); 1317 } 1318 1319 static int 1320 monitor_valid_hostbasedblob(const u_char *data, u_int datalen, 1321 const char *cuser, const char *chost) 1322 { 1323 struct sshbuf *b; 1324 const u_char *p; 1325 char *cp, *userstyle; 1326 size_t len; 1327 int r, fail = 0; 1328 u_char type; 1329 1330 if ((b = sshbuf_from(data, datalen)) == NULL) 1331 fatal_f("sshbuf_new"); 1332 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1333 fatal_fr(r, "parse sessionid"); 1334 1335 if ((session_id2 == NULL) || 1336 (len != session_id2_len) || 1337 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1338 fail++; 1339 1340 if ((r = sshbuf_get_u8(b, &type)) != 0) 1341 fatal_fr(r, "parse type"); 1342 if (type != SSH2_MSG_USERAUTH_REQUEST) 1343 fail++; 1344 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1345 fatal_fr(r, "parse userstyle"); 1346 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1347 authctxt->style ? ":" : "", 1348 authctxt->style ? authctxt->style : ""); 1349 if (strcmp(userstyle, cp) != 0) { 1350 logit("wrong user name passed to monitor: " 1351 "expected %s != %.100s", userstyle, cp); 1352 fail++; 1353 } 1354 free(userstyle); 1355 free(cp); 1356 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1357 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1358 fatal_fr(r, "parse method"); 1359 if (strcmp(cp, "hostbased") != 0) 1360 fail++; 1361 free(cp); 1362 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1363 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1364 fatal_fr(r, "parse pk"); 1365 1366 /* verify client host, strip trailing dot if necessary */ 1367 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1368 fatal_fr(r, "parse host"); 1369 if (((len = strlen(cp)) > 0) && cp[len - 1] == '.') 1370 cp[len - 1] = '\0'; 1371 if (strcmp(cp, chost) != 0) 1372 fail++; 1373 free(cp); 1374 1375 /* verify client user */ 1376 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1377 fatal_fr(r, "parse ruser"); 1378 if (strcmp(cp, cuser) != 0) 1379 fail++; 1380 free(cp); 1381 1382 if (sshbuf_len(b) != 0) 1383 fail++; 1384 sshbuf_free(b); 1385 return (fail == 0); 1386 } 1387 1388 int 1389 mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m) 1390 { 1391 struct sshkey *key; 1392 const u_char *signature, *data, *blob; 1393 char *sigalg = NULL, *fp = NULL; 1394 size_t signaturelen, datalen, bloblen; 1395 int r, ret, req_presence = 0, req_verify = 0, valid_data = 0; 1396 int encoded_ret; 1397 struct sshkey_sig_details *sig_details = NULL; 1398 1399 if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 || 1400 (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 || 1401 (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 || 1402 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0) 1403 fatal_fr(r, "parse"); 1404 1405 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1406 !monitor_allowed_key(blob, bloblen)) 1407 fatal_f("bad key, not previously allowed"); 1408 1409 /* Empty signature algorithm means NULL. */ 1410 if (*sigalg == '\0') { 1411 free(sigalg); 1412 sigalg = NULL; 1413 } 1414 1415 /* XXX use sshkey_froms here; need to change key_blob, etc. */ 1416 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0) 1417 fatal_fr(r, "parse key"); 1418 1419 switch (key_blobtype) { 1420 case MM_USERKEY: 1421 valid_data = monitor_valid_userblob(ssh, data, datalen); 1422 auth_method = "publickey"; 1423 break; 1424 case MM_HOSTKEY: 1425 valid_data = monitor_valid_hostbasedblob(data, datalen, 1426 hostbased_cuser, hostbased_chost); 1427 auth_method = "hostbased"; 1428 break; 1429 default: 1430 valid_data = 0; 1431 break; 1432 } 1433 if (!valid_data) 1434 fatal_f("bad %s signature data blob", 1435 key_blobtype == MM_USERKEY ? "userkey" : 1436 (key_blobtype == MM_HOSTKEY ? "hostkey" : "unknown")); 1437 1438 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 1439 SSH_FP_DEFAULT)) == NULL) 1440 fatal_f("sshkey_fingerprint failed"); 1441 1442 ret = sshkey_verify(key, signature, signaturelen, data, datalen, 1443 sigalg, ssh->compat, &sig_details); 1444 debug3_f("%s %s signature using %s %s%s%s", auth_method, 1445 sshkey_type(key), sigalg == NULL ? "default" : sigalg, 1446 (ret == 0) ? "verified" : "unverified", 1447 (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : ""); 1448 1449 if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) { 1450 req_presence = (options.pubkey_auth_options & 1451 PUBKEYAUTH_TOUCH_REQUIRED) || 1452 !key_opts->no_require_user_presence; 1453 if (req_presence && 1454 (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) { 1455 error("public key %s %s signature for %s%s from %.128s " 1456 "port %d rejected: user presence " 1457 "(authenticator touch) requirement not met ", 1458 sshkey_type(key), fp, 1459 authctxt->valid ? "" : "invalid user ", 1460 authctxt->user, ssh_remote_ipaddr(ssh), 1461 ssh_remote_port(ssh)); 1462 ret = SSH_ERR_SIGNATURE_INVALID; 1463 } 1464 req_verify = (options.pubkey_auth_options & 1465 PUBKEYAUTH_VERIFY_REQUIRED) || key_opts->require_verify; 1466 if (req_verify && 1467 (sig_details->sk_flags & SSH_SK_USER_VERIFICATION_REQD) == 0) { 1468 error("public key %s %s signature for %s%s from %.128s " 1469 "port %d rejected: user verification requirement " 1470 "not met ", sshkey_type(key), fp, 1471 authctxt->valid ? "" : "invalid user ", 1472 authctxt->user, ssh_remote_ipaddr(ssh), 1473 ssh_remote_port(ssh)); 1474 ret = SSH_ERR_SIGNATURE_INVALID; 1475 } 1476 } 1477 auth2_record_key(authctxt, ret == 0, key); 1478 1479 if (key_blobtype == MM_USERKEY) 1480 auth_activate_options(ssh, key_opts); 1481 monitor_reset_key_state(); 1482 1483 sshbuf_reset(m); 1484 1485 /* encode ret != 0 as positive integer, since we're sending u32 */ 1486 encoded_ret = (ret != 0); 1487 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 || 1488 (r = sshbuf_put_u8(m, sig_details != NULL)) != 0) 1489 fatal_fr(r, "assemble"); 1490 if (sig_details != NULL) { 1491 if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 || 1492 (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0) 1493 fatal_fr(r, "assemble sk"); 1494 } 1495 sshkey_sig_details_free(sig_details); 1496 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1497 1498 free(sigalg); 1499 free(fp); 1500 sshkey_free(key); 1501 1502 return ret == 0; 1503 } 1504 1505 static void 1506 mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw) 1507 { 1508 socklen_t fromlen; 1509 struct sockaddr_storage from; 1510 1511 /* 1512 * Get IP address of client. If the connection is not a socket, let 1513 * the address be 0.0.0.0. 1514 */ 1515 memset(&from, 0, sizeof(from)); 1516 fromlen = sizeof(from); 1517 if (ssh_packet_connection_is_on_socket(ssh)) { 1518 if (getpeername(ssh_packet_get_connection_in(ssh), 1519 (struct sockaddr *)&from, &fromlen) == -1) { 1520 debug("getpeername: %.100s", strerror(errno)); 1521 cleanup_exit(255); 1522 } 1523 } 1524 /* Record that there was a login on that tty from the remote host. */ 1525 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1526 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1527 (struct sockaddr *)&from, fromlen); 1528 } 1529 1530 static void 1531 mm_session_close(Session *s) 1532 { 1533 debug3_f("session %d pid %ld", s->self, (long)s->pid); 1534 if (s->ttyfd != -1) { 1535 debug3_f("tty %s ptyfd %d", s->tty, s->ptyfd); 1536 session_pty_cleanup2(s); 1537 } 1538 session_unused(s->self); 1539 } 1540 1541 int 1542 mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m) 1543 { 1544 extern struct monitor *pmonitor; 1545 Session *s; 1546 int r, res, fd0; 1547 1548 debug3_f("entering"); 1549 1550 sshbuf_reset(m); 1551 s = session_new(); 1552 if (s == NULL) 1553 goto error; 1554 s->authctxt = authctxt; 1555 s->pw = authctxt->pw; 1556 s->pid = pmonitor->m_pid; 1557 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1558 if (res == 0) 1559 goto error; 1560 pty_setowner(authctxt->pw, s->tty); 1561 1562 if ((r = sshbuf_put_u32(m, 1)) != 0 || 1563 (r = sshbuf_put_cstring(m, s->tty)) != 0) 1564 fatal_fr(r, "assemble"); 1565 1566 /* We need to trick ttyslot */ 1567 if (dup2(s->ttyfd, 0) == -1) 1568 fatal_f("dup2"); 1569 1570 mm_record_login(ssh, s, authctxt->pw); 1571 1572 /* Now we can close the file descriptor again */ 1573 close(0); 1574 1575 /* send messages generated by record_login */ 1576 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0) 1577 fatal_fr(r, "assemble loginmsg"); 1578 sshbuf_reset(loginmsg); 1579 1580 mm_request_send(sock, MONITOR_ANS_PTY, m); 1581 1582 if (mm_send_fd(sock, s->ptyfd) == -1 || 1583 mm_send_fd(sock, s->ttyfd) == -1) 1584 fatal_f("send fds failed"); 1585 1586 /* make sure nothing uses fd 0 */ 1587 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1588 fatal_f("open(/dev/null): %s", strerror(errno)); 1589 if (fd0 != 0) 1590 error_f("fd0 %d != 0", fd0); 1591 1592 /* slave side of pty is not needed */ 1593 close(s->ttyfd); 1594 s->ttyfd = s->ptyfd; 1595 /* no need to dup() because nobody closes ptyfd */ 1596 s->ptymaster = s->ptyfd; 1597 1598 debug3_f("tty %s ptyfd %d", s->tty, s->ttyfd); 1599 1600 return (0); 1601 1602 error: 1603 if (s != NULL) 1604 mm_session_close(s); 1605 if ((r = sshbuf_put_u32(m, 0)) != 0) 1606 fatal_fr(r, "assemble 0"); 1607 mm_request_send(sock, MONITOR_ANS_PTY, m); 1608 return (0); 1609 } 1610 1611 int 1612 mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m) 1613 { 1614 Session *s; 1615 char *tty; 1616 int r; 1617 1618 debug3_f("entering"); 1619 1620 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0) 1621 fatal_fr(r, "parse tty"); 1622 if ((s = session_by_tty(tty)) != NULL) 1623 mm_session_close(s); 1624 sshbuf_reset(m); 1625 free(tty); 1626 return (0); 1627 } 1628 1629 int 1630 mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req) 1631 { 1632 extern struct monitor *pmonitor; 1633 int res, status; 1634 1635 debug3_f("tearing down sessions"); 1636 1637 /* The child is terminating */ 1638 session_destroy_all(ssh, &mm_session_close); 1639 1640 #ifdef USE_PAM 1641 if (options.use_pam) 1642 sshpam_cleanup(); 1643 #endif 1644 1645 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1646 if (errno != EINTR) 1647 exit(1); 1648 1649 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1650 1651 /* Terminate process */ 1652 exit(res); 1653 } 1654 1655 #ifdef SSH_AUDIT_EVENTS 1656 /* Report that an audit event occurred */ 1657 int 1658 mm_answer_audit_event(struct ssh *ssh, int socket, struct sshbuf *m) 1659 { 1660 u_int n; 1661 ssh_audit_event_t event; 1662 int r; 1663 1664 debug3("%s entering", __func__); 1665 1666 if ((r = sshbuf_get_u32(m, &n)) != 0) 1667 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1668 event = (ssh_audit_event_t)n; 1669 switch (event) { 1670 case SSH_AUTH_FAIL_PUBKEY: 1671 case SSH_AUTH_FAIL_HOSTBASED: 1672 case SSH_AUTH_FAIL_GSSAPI: 1673 case SSH_LOGIN_EXCEED_MAXTRIES: 1674 case SSH_LOGIN_ROOT_DENIED: 1675 case SSH_CONNECTION_CLOSE: 1676 case SSH_INVALID_USER: 1677 audit_event(ssh, event); 1678 break; 1679 default: 1680 fatal("Audit event type %d not permitted", event); 1681 } 1682 1683 return (0); 1684 } 1685 1686 int 1687 mm_answer_audit_command(struct ssh *ssh, int socket, struct sshbuf *m) 1688 { 1689 char *cmd; 1690 int r; 1691 1692 debug3("%s entering", __func__); 1693 if ((r = sshbuf_get_cstring(m, &cmd, NULL)) != 0) 1694 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1695 /* sanity check command, if so how? */ 1696 audit_run_command(cmd); 1697 free(cmd); 1698 return (0); 1699 } 1700 #endif /* SSH_AUDIT_EVENTS */ 1701 1702 void 1703 monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor) 1704 { 1705 ssh_clear_newkeys(ssh, MODE_IN); 1706 ssh_clear_newkeys(ssh, MODE_OUT); 1707 sshbuf_free(child_state); 1708 child_state = NULL; 1709 } 1710 1711 void 1712 monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor) 1713 { 1714 struct kex *kex; 1715 int r; 1716 1717 debug3_f("packet_set_state"); 1718 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1719 fatal_fr(r, "packet_set_state"); 1720 sshbuf_free(child_state); 1721 child_state = NULL; 1722 if ((kex = ssh->kex) == NULL) 1723 fatal_f("internal error: ssh->kex == NULL"); 1724 if (session_id2_len != sshbuf_len(ssh->kex->session_id)) { 1725 fatal_f("incorrect session id length %zu (expected %u)", 1726 sshbuf_len(ssh->kex->session_id), session_id2_len); 1727 } 1728 if (memcmp(sshbuf_ptr(ssh->kex->session_id), session_id2, 1729 session_id2_len) != 0) 1730 fatal_f("session ID mismatch"); 1731 /* XXX set callbacks */ 1732 #ifdef WITH_OPENSSL 1733 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server; 1734 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server; 1735 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server; 1736 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server; 1737 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server; 1738 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1739 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1740 # ifdef OPENSSL_HAS_ECC 1741 kex->kex[KEX_ECDH_SHA2] = kex_gen_server; 1742 # endif 1743 #endif /* WITH_OPENSSL */ 1744 kex->kex[KEX_C25519_SHA256] = kex_gen_server; 1745 kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server; 1746 kex->load_host_public_key=&get_hostkey_public_by_type; 1747 kex->load_host_private_key=&get_hostkey_private_by_type; 1748 kex->host_key_index=&get_hostkey_index; 1749 kex->sign = sshd_hostkey_sign; 1750 } 1751 1752 /* This function requires careful sanity checking */ 1753 1754 void 1755 mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor) 1756 { 1757 debug3_f("Waiting for new keys"); 1758 1759 if ((child_state = sshbuf_new()) == NULL) 1760 fatal_f("sshbuf_new failed"); 1761 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1762 child_state); 1763 debug3_f("GOT new keys"); 1764 } 1765 1766 1767 /* XXX */ 1768 1769 #define FD_CLOSEONEXEC(x) do { \ 1770 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1771 fatal("fcntl(%d, F_SETFD)", x); \ 1772 } while (0) 1773 1774 static void 1775 monitor_openfds(struct monitor *mon, int do_logfds) 1776 { 1777 int pair[2]; 1778 #ifdef SO_ZEROIZE 1779 int on = 1; 1780 #endif 1781 1782 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1783 fatal_f("socketpair: %s", strerror(errno)); 1784 #ifdef SO_ZEROIZE 1785 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1786 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno)); 1787 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1788 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno)); 1789 #endif 1790 FD_CLOSEONEXEC(pair[0]); 1791 FD_CLOSEONEXEC(pair[1]); 1792 mon->m_recvfd = pair[0]; 1793 mon->m_sendfd = pair[1]; 1794 1795 if (do_logfds) { 1796 if (pipe(pair) == -1) 1797 fatal_f("pipe: %s", strerror(errno)); 1798 FD_CLOSEONEXEC(pair[0]); 1799 FD_CLOSEONEXEC(pair[1]); 1800 mon->m_log_recvfd = pair[0]; 1801 mon->m_log_sendfd = pair[1]; 1802 } else 1803 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1804 } 1805 1806 #define MM_MEMSIZE 65536 1807 1808 struct monitor * 1809 monitor_init(void) 1810 { 1811 struct monitor *mon; 1812 1813 mon = xcalloc(1, sizeof(*mon)); 1814 monitor_openfds(mon, 1); 1815 1816 return mon; 1817 } 1818 1819 void 1820 monitor_reinit(struct monitor *mon) 1821 { 1822 monitor_openfds(mon, 0); 1823 } 1824 1825 #ifdef GSSAPI 1826 int 1827 mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1828 { 1829 gss_OID_desc goid; 1830 OM_uint32 major; 1831 size_t len; 1832 u_char *p; 1833 int r; 1834 1835 if (!options.gss_authentication) 1836 fatal_f("GSSAPI authentication not enabled"); 1837 1838 if ((r = sshbuf_get_string(m, &p, &len)) != 0) 1839 fatal_fr(r, "parse"); 1840 goid.elements = p; 1841 goid.length = len; 1842 1843 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1844 1845 free(goid.elements); 1846 1847 sshbuf_reset(m); 1848 if ((r = sshbuf_put_u32(m, major)) != 0) 1849 fatal_fr(r, "assemble"); 1850 1851 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1852 1853 /* Now we have a context, enable the step */ 1854 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1855 1856 return (0); 1857 } 1858 1859 int 1860 mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1861 { 1862 gss_buffer_desc in; 1863 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1864 OM_uint32 major, minor; 1865 OM_uint32 flags = 0; /* GSI needs this */ 1866 int r; 1867 1868 if (!options.gss_authentication) 1869 fatal_f("GSSAPI authentication not enabled"); 1870 1871 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0) 1872 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1873 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1874 free(in.value); 1875 1876 sshbuf_reset(m); 1877 if ((r = sshbuf_put_u32(m, major)) != 0 || 1878 (r = sshbuf_put_string(m, out.value, out.length)) != 0 || 1879 (r = sshbuf_put_u32(m, flags)) != 0) 1880 fatal_fr(r, "assemble"); 1881 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1882 1883 gss_release_buffer(&minor, &out); 1884 1885 if (major == GSS_S_COMPLETE) { 1886 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1887 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1888 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1889 } 1890 return (0); 1891 } 1892 1893 int 1894 mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m) 1895 { 1896 gss_buffer_desc gssbuf, mic; 1897 OM_uint32 ret; 1898 int r; 1899 1900 if (!options.gss_authentication) 1901 fatal_f("GSSAPI authentication not enabled"); 1902 1903 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 || 1904 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0) 1905 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1906 1907 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1908 1909 free(gssbuf.value); 1910 free(mic.value); 1911 1912 sshbuf_reset(m); 1913 if ((r = sshbuf_put_u32(m, ret)) != 0) 1914 fatal_fr(r, "assemble"); 1915 1916 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1917 1918 if (!GSS_ERROR(ret)) 1919 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1920 1921 return (0); 1922 } 1923 1924 int 1925 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m) 1926 { 1927 int r, authenticated; 1928 const char *displayname; 1929 1930 if (!options.gss_authentication) 1931 fatal_f("GSSAPI authentication not enabled"); 1932 1933 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1934 1935 sshbuf_reset(m); 1936 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 1937 fatal_fr(r, "assemble"); 1938 1939 debug3_f("sending result %d", authenticated); 1940 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1941 1942 auth_method = "gssapi-with-mic"; 1943 1944 if ((displayname = ssh_gssapi_displayname()) != NULL) 1945 auth2_record_info(authctxt, "%s", displayname); 1946 1947 /* Monitor loop will terminate if authenticated */ 1948 return (authenticated); 1949 } 1950 #endif /* GSSAPI */ 1951 1952