1 /* $OpenBSD: monitor.c,v 1.228 2021/08/11 05:20:17 djm Exp $ */ 2 /* 3 * Copyright 2002 Niels Provos <provos@citi.umich.edu> 4 * Copyright 2002 Markus Friedl <markus@openbsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include "includes.h" 29 30 #include <sys/types.h> 31 #include <sys/socket.h> 32 #include <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_rsa_keyallowed(struct ssh *, int, struct sshbuf *); 129 int mm_answer_rsa_challenge(struct ssh *, int, struct sshbuf *); 130 int mm_answer_rsa_response(struct ssh *, int, struct sshbuf *); 131 int mm_answer_sesskey(struct ssh *, int, struct sshbuf *); 132 int mm_answer_sessid(struct ssh *, int, struct sshbuf *); 133 134 #ifdef USE_PAM 135 int mm_answer_pam_start(struct ssh *, int, struct sshbuf *); 136 int mm_answer_pam_account(struct ssh *, int, struct sshbuf *); 137 int mm_answer_pam_init_ctx(struct ssh *, int, struct sshbuf *); 138 int mm_answer_pam_query(struct ssh *, int, struct sshbuf *); 139 int mm_answer_pam_respond(struct ssh *, int, struct sshbuf *); 140 int mm_answer_pam_free_ctx(struct ssh *, int, struct sshbuf *); 141 #endif 142 143 #ifdef GSSAPI 144 int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *); 145 int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *); 146 int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *); 147 int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *); 148 #endif 149 150 #ifdef SSH_AUDIT_EVENTS 151 int mm_answer_audit_event(struct ssh *, int, struct sshbuf *); 152 int mm_answer_audit_command(struct ssh *, int, struct sshbuf *); 153 #endif 154 155 static Authctxt *authctxt; 156 157 /* local state for key verify */ 158 static u_char *key_blob = NULL; 159 static size_t key_bloblen = 0; 160 static u_int key_blobtype = MM_NOKEY; 161 static struct sshauthopt *key_opts = NULL; 162 static char *hostbased_cuser = NULL; 163 static char *hostbased_chost = NULL; 164 static char *auth_method = "unknown"; 165 static char *auth_submethod = NULL; 166 static u_int session_id2_len = 0; 167 static u_char *session_id2 = NULL; 168 static pid_t monitor_child_pid; 169 170 struct mon_table { 171 enum monitor_reqtype type; 172 int flags; 173 int (*f)(struct ssh *, int, struct sshbuf *); 174 }; 175 176 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 177 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 178 #define MON_ONCE 0x0010 /* Disable after calling */ 179 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 180 181 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 182 183 #define MON_PERMIT 0x1000 /* Request is permitted */ 184 185 static int monitor_read(struct ssh *, struct monitor *, struct mon_table *, 186 struct mon_table **); 187 static int monitor_read_log(struct monitor *); 188 189 struct mon_table mon_dispatch_proto20[] = { 190 #ifdef WITH_OPENSSL 191 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 192 #endif 193 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 194 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 195 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 196 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 197 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 198 #ifdef USE_PAM 199 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 200 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 201 {MONITOR_REQ_PAM_INIT_CTX, MON_ONCE, mm_answer_pam_init_ctx}, 202 {MONITOR_REQ_PAM_QUERY, 0, mm_answer_pam_query}, 203 {MONITOR_REQ_PAM_RESPOND, MON_ONCE, mm_answer_pam_respond}, 204 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 205 #endif 206 #ifdef SSH_AUDIT_EVENTS 207 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 208 #endif 209 #ifdef BSD_AUTH 210 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 211 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 212 #endif 213 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 214 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 215 #ifdef GSSAPI 216 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 217 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx}, 218 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok}, 219 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic}, 220 #endif 221 {0, 0, NULL} 222 }; 223 224 struct mon_table mon_dispatch_postauth20[] = { 225 #ifdef WITH_OPENSSL 226 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 227 #endif 228 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 229 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 230 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 231 {MONITOR_REQ_TERM, 0, mm_answer_term}, 232 #ifdef SSH_AUDIT_EVENTS 233 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 234 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command}, 235 #endif 236 {0, 0, NULL} 237 }; 238 239 struct mon_table *mon_dispatch; 240 241 /* Specifies if a certain message is allowed at the moment */ 242 static void 243 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 244 { 245 while (ent->f != NULL) { 246 if (ent->type == type) { 247 ent->flags &= ~MON_PERMIT; 248 ent->flags |= permit ? MON_PERMIT : 0; 249 return; 250 } 251 ent++; 252 } 253 } 254 255 static void 256 monitor_permit_authentications(int permit) 257 { 258 struct mon_table *ent = mon_dispatch; 259 260 while (ent->f != NULL) { 261 if (ent->flags & MON_AUTH) { 262 ent->flags &= ~MON_PERMIT; 263 ent->flags |= permit ? MON_PERMIT : 0; 264 } 265 ent++; 266 } 267 } 268 269 void 270 monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor) 271 { 272 struct mon_table *ent; 273 int authenticated = 0, partial = 0; 274 275 debug3("preauth child monitor started"); 276 277 if (pmonitor->m_recvfd >= 0) 278 close(pmonitor->m_recvfd); 279 if (pmonitor->m_log_sendfd >= 0) 280 close(pmonitor->m_log_sendfd); 281 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 282 283 authctxt = (Authctxt *)ssh->authctxt; 284 memset(authctxt, 0, sizeof(*authctxt)); 285 ssh->authctxt = authctxt; 286 287 authctxt->loginmsg = loginmsg; 288 289 mon_dispatch = mon_dispatch_proto20; 290 /* Permit requests for moduli and signatures */ 291 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 292 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 293 294 /* The first few requests do not require asynchronous access */ 295 while (!authenticated) { 296 partial = 0; 297 auth_method = "unknown"; 298 auth_submethod = NULL; 299 auth2_authctxt_reset_info(authctxt); 300 301 authenticated = (monitor_read(ssh, pmonitor, 302 mon_dispatch, &ent) == 1); 303 304 /* Special handling for multiple required authentications */ 305 if (options.num_auth_methods != 0) { 306 if (authenticated && 307 !auth2_update_methods_lists(authctxt, 308 auth_method, auth_submethod)) { 309 debug3_f("method %s: partial", auth_method); 310 authenticated = 0; 311 partial = 1; 312 } 313 } 314 315 if (authenticated) { 316 if (!(ent->flags & MON_AUTHDECIDE)) 317 fatal_f("unexpected authentication from %d", 318 ent->type); 319 if (authctxt->pw->pw_uid == 0 && 320 !auth_root_allowed(ssh, auth_method)) 321 authenticated = 0; 322 #ifdef USE_PAM 323 /* PAM needs to perform account checks after auth */ 324 if (options.use_pam && authenticated) { 325 struct sshbuf *m; 326 327 if ((m = sshbuf_new()) == NULL) 328 fatal("%s: sshbuf_new failed", 329 __func__); 330 mm_request_receive_expect(pmonitor->m_sendfd, 331 MONITOR_REQ_PAM_ACCOUNT, m); 332 authenticated = mm_answer_pam_account( 333 ssh, pmonitor->m_sendfd, m); 334 sshbuf_free(m); 335 } 336 #endif 337 } 338 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 339 auth_log(ssh, authenticated, partial, 340 auth_method, auth_submethod); 341 if (!partial && !authenticated) 342 authctxt->failures++; 343 if (authenticated || partial) { 344 auth2_update_session_info(authctxt, 345 auth_method, auth_submethod); 346 } 347 } 348 } 349 350 if (!authctxt->valid) 351 fatal_f("authenticated invalid user"); 352 if (strcmp(auth_method, "unknown") == 0) 353 fatal_f("authentication method name unknown"); 354 355 debug_f("user %s authenticated by privileged process", authctxt->user); 356 ssh->authctxt = NULL; 357 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 358 359 mm_get_keystate(ssh, pmonitor); 360 361 /* Drain any buffered messages from the child */ 362 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 363 ; 364 365 if (pmonitor->m_recvfd >= 0) 366 close(pmonitor->m_recvfd); 367 if (pmonitor->m_log_sendfd >= 0) 368 close(pmonitor->m_log_sendfd); 369 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 370 } 371 372 static void 373 monitor_set_child_handler(pid_t pid) 374 { 375 monitor_child_pid = pid; 376 } 377 378 static void 379 monitor_child_handler(int sig) 380 { 381 kill(monitor_child_pid, sig); 382 } 383 384 void 385 monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor) 386 { 387 close(pmonitor->m_recvfd); 388 pmonitor->m_recvfd = -1; 389 390 monitor_set_child_handler(pmonitor->m_pid); 391 ssh_signal(SIGHUP, &monitor_child_handler); 392 ssh_signal(SIGTERM, &monitor_child_handler); 393 ssh_signal(SIGINT, &monitor_child_handler); 394 #ifdef SIGXFSZ 395 ssh_signal(SIGXFSZ, SIG_IGN); 396 #endif 397 398 mon_dispatch = mon_dispatch_postauth20; 399 400 /* Permit requests for moduli and signatures */ 401 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 402 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 403 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 404 405 if (auth_opts->permit_pty_flag) { 406 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 407 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 408 } 409 410 for (;;) 411 monitor_read(ssh, pmonitor, mon_dispatch, NULL); 412 } 413 414 static int 415 monitor_read_log(struct monitor *pmonitor) 416 { 417 struct sshbuf *logmsg; 418 u_int len, level, forced; 419 char *msg; 420 u_char *p; 421 int r; 422 423 if ((logmsg = sshbuf_new()) == NULL) 424 fatal_f("sshbuf_new"); 425 426 /* Read length */ 427 if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0) 428 fatal_fr(r, "reserve len"); 429 if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) { 430 if (errno == EPIPE) { 431 sshbuf_free(logmsg); 432 debug_f("child log fd closed"); 433 close(pmonitor->m_log_recvfd); 434 pmonitor->m_log_recvfd = -1; 435 return -1; 436 } 437 fatal_f("log fd read: %s", strerror(errno)); 438 } 439 if ((r = sshbuf_get_u32(logmsg, &len)) != 0) 440 fatal_fr(r, "parse len"); 441 if (len <= 4 || len > 8192) 442 fatal_f("invalid log message length %u", len); 443 444 /* Read severity, message */ 445 sshbuf_reset(logmsg); 446 if ((r = sshbuf_reserve(logmsg, len, &p)) != 0) 447 fatal_fr(r, "reserve msg"); 448 if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len) 449 fatal_f("log fd read: %s", strerror(errno)); 450 if ((r = sshbuf_get_u32(logmsg, &level)) != 0 || 451 (r = sshbuf_get_u32(logmsg, &forced)) != 0 || 452 (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0) 453 fatal_fr(r, "parse"); 454 455 /* Log it */ 456 if (log_level_name(level) == NULL) 457 fatal_f("invalid log level %u (corrupted message?)", level); 458 sshlogdirect(level, forced, "%s [preauth]", msg); 459 460 sshbuf_free(logmsg); 461 free(msg); 462 463 return 0; 464 } 465 466 static int 467 monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent, 468 struct mon_table **pent) 469 { 470 struct sshbuf *m; 471 int r, ret; 472 u_char type; 473 struct pollfd pfd[2]; 474 475 for (;;) { 476 memset(&pfd, 0, sizeof(pfd)); 477 pfd[0].fd = pmonitor->m_sendfd; 478 pfd[0].events = POLLIN; 479 pfd[1].fd = pmonitor->m_log_recvfd; 480 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 481 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 482 if (errno == EINTR || errno == EAGAIN) 483 continue; 484 fatal_f("poll: %s", strerror(errno)); 485 } 486 if (pfd[1].revents) { 487 /* 488 * Drain all log messages before processing next 489 * monitor request. 490 */ 491 monitor_read_log(pmonitor); 492 continue; 493 } 494 if (pfd[0].revents) 495 break; /* Continues below */ 496 } 497 498 if ((m = sshbuf_new()) == NULL) 499 fatal_f("sshbuf_new"); 500 501 mm_request_receive(pmonitor->m_sendfd, m); 502 if ((r = sshbuf_get_u8(m, &type)) != 0) 503 fatal_fr(r, "parse type"); 504 505 debug3_f("checking request %d", type); 506 507 while (ent->f != NULL) { 508 if (ent->type == type) 509 break; 510 ent++; 511 } 512 513 if (ent->f != NULL) { 514 if (!(ent->flags & MON_PERMIT)) 515 fatal_f("unpermitted request %d", type); 516 ret = (*ent->f)(ssh, pmonitor->m_sendfd, m); 517 sshbuf_free(m); 518 519 /* The child may use this request only once, disable it */ 520 if (ent->flags & MON_ONCE) { 521 debug2_f("%d used once, disabling now", type); 522 ent->flags &= ~MON_PERMIT; 523 } 524 525 if (pent != NULL) 526 *pent = ent; 527 528 return ret; 529 } 530 531 fatal_f("unsupported request: %d", type); 532 533 /* NOTREACHED */ 534 return (-1); 535 } 536 537 /* allowed key state */ 538 static int 539 monitor_allowed_key(const u_char *blob, u_int bloblen) 540 { 541 /* make sure key is allowed */ 542 if (key_blob == NULL || key_bloblen != bloblen || 543 timingsafe_bcmp(key_blob, blob, key_bloblen)) 544 return (0); 545 return (1); 546 } 547 548 static void 549 monitor_reset_key_state(void) 550 { 551 /* reset state */ 552 free(key_blob); 553 free(hostbased_cuser); 554 free(hostbased_chost); 555 sshauthopt_free(key_opts); 556 key_blob = NULL; 557 key_bloblen = 0; 558 key_blobtype = MM_NOKEY; 559 key_opts = NULL; 560 hostbased_cuser = NULL; 561 hostbased_chost = NULL; 562 } 563 564 #ifdef WITH_OPENSSL 565 int 566 mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m) 567 { 568 DH *dh; 569 const BIGNUM *dh_p, *dh_g; 570 int r; 571 u_int min, want, max; 572 573 if ((r = sshbuf_get_u32(m, &min)) != 0 || 574 (r = sshbuf_get_u32(m, &want)) != 0 || 575 (r = sshbuf_get_u32(m, &max)) != 0) 576 fatal_fr(r, "parse"); 577 578 debug3_f("got parameters: %d %d %d", min, want, max); 579 /* We need to check here, too, in case the child got corrupted */ 580 if (max < min || want < min || max < want) 581 fatal_f("bad parameters: %d %d %d", min, want, max); 582 583 sshbuf_reset(m); 584 585 dh = choose_dh(min, want, max); 586 if (dh == NULL) { 587 if ((r = sshbuf_put_u8(m, 0)) != 0) 588 fatal_fr(r, "assemble empty"); 589 return (0); 590 } else { 591 /* Send first bignum */ 592 DH_get0_pqg(dh, &dh_p, NULL, &dh_g); 593 if ((r = sshbuf_put_u8(m, 1)) != 0 || 594 (r = sshbuf_put_bignum2(m, dh_p)) != 0 || 595 (r = sshbuf_put_bignum2(m, dh_g)) != 0) 596 fatal_fr(r, "assemble"); 597 598 DH_free(dh); 599 } 600 mm_request_send(sock, MONITOR_ANS_MODULI, m); 601 return (0); 602 } 603 #endif 604 605 int 606 mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m) 607 { 608 extern int auth_sock; /* XXX move to state struct? */ 609 struct sshkey *key; 610 struct sshbuf *sigbuf = NULL; 611 u_char *p = NULL, *signature = NULL; 612 char *alg = NULL; 613 size_t datlen, siglen, alglen; 614 int r, is_proof = 0; 615 u_int keyid, compat; 616 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 617 618 debug3_f("entering"); 619 620 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 621 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 622 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0 || 623 (r = sshbuf_get_u32(m, &compat)) != 0) 624 fatal_fr(r, "parse"); 625 if (keyid > INT_MAX) 626 fatal_f("invalid key ID"); 627 628 /* 629 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 630 * SHA384 (48 bytes) and SHA512 (64 bytes). 631 * 632 * Otherwise, verify the signature request is for a hostkey 633 * proof. 634 * 635 * XXX perform similar check for KEX signature requests too? 636 * it's not trivial, since what is signed is the hash, rather 637 * than the full kex structure... 638 */ 639 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 640 /* 641 * Construct expected hostkey proof and compare it to what 642 * the client sent us. 643 */ 644 if (session_id2_len == 0) /* hostkeys is never first */ 645 fatal_f("bad data length: %zu", datlen); 646 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 647 fatal_f("no hostkey for index %d", keyid); 648 if ((sigbuf = sshbuf_new()) == NULL) 649 fatal_f("sshbuf_new"); 650 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 651 (r = sshbuf_put_string(sigbuf, session_id2, 652 session_id2_len)) != 0 || 653 (r = sshkey_puts(key, sigbuf)) != 0) 654 fatal_fr(r, "assemble private key proof"); 655 if (datlen != sshbuf_len(sigbuf) || 656 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 657 fatal_f("bad data length: %zu, hostkey proof len %zu", 658 datlen, sshbuf_len(sigbuf)); 659 sshbuf_free(sigbuf); 660 is_proof = 1; 661 } 662 663 /* save session id, it will be passed on the first call */ 664 if (session_id2_len == 0) { 665 session_id2_len = datlen; 666 session_id2 = xmalloc(session_id2_len); 667 memcpy(session_id2, p, session_id2_len); 668 } 669 670 if ((key = get_hostkey_by_index(keyid)) != NULL) { 671 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 672 options.sk_provider, NULL, compat)) != 0) 673 fatal_fr(r, "sign"); 674 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 675 auth_sock > 0) { 676 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 677 p, datlen, alg, compat)) != 0) 678 fatal_fr(r, "agent sign"); 679 } else 680 fatal_f("no hostkey from index %d", keyid); 681 682 debug3_f("%s %s signature len=%zu", alg, 683 is_proof ? "hostkey proof" : "KEX", siglen); 684 685 sshbuf_reset(m); 686 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 687 fatal_fr(r, "assemble"); 688 689 free(alg); 690 free(p); 691 free(signature); 692 693 mm_request_send(sock, MONITOR_ANS_SIGN, m); 694 695 /* Turn on permissions for getpwnam */ 696 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 697 698 return (0); 699 } 700 701 #define PUTPW(b, id) \ 702 do { \ 703 if ((r = sshbuf_put_string(b, \ 704 &pwent->id, sizeof(pwent->id))) != 0) \ 705 fatal_fr(r, "assemble %s", #id); \ 706 } while (0) 707 708 /* Retrieves the password entry and also checks if the user is permitted */ 709 int 710 mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m) 711 { 712 char *username; 713 struct passwd *pwent; 714 int r, allowed = 0; 715 u_int i; 716 717 debug3_f("entering"); 718 719 if (authctxt->attempt++ != 0) 720 fatal_f("multiple attempts for getpwnam"); 721 722 if ((r = sshbuf_get_cstring(m, &username, NULL)) != 0) 723 fatal_fr(r, "parse"); 724 725 pwent = getpwnamallow(ssh, username); 726 727 authctxt->user = xstrdup(username); 728 setproctitle("%s [priv]", pwent ? username : "unknown"); 729 free(username); 730 731 sshbuf_reset(m); 732 733 if (pwent == NULL) { 734 if ((r = sshbuf_put_u8(m, 0)) != 0) 735 fatal_fr(r, "assemble fakepw"); 736 authctxt->pw = fakepw(); 737 goto out; 738 } 739 740 allowed = 1; 741 authctxt->pw = pwent; 742 authctxt->valid = 1; 743 744 /* XXX send fake class/dir/shell, etc. */ 745 if ((r = sshbuf_put_u8(m, 1)) != 0) 746 fatal_fr(r, "assemble ok"); 747 PUTPW(m, pw_uid); 748 PUTPW(m, pw_gid); 749 #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE 750 PUTPW(m, pw_change); 751 #endif 752 #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE 753 PUTPW(m, pw_expire); 754 #endif 755 if ((r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || 756 (r = sshbuf_put_cstring(m, "*")) != 0 || 757 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS 758 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 || 759 #endif 760 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS 761 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 || 762 #endif 763 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 || 764 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0) 765 fatal_fr(r, "assemble pw"); 766 767 out: 768 ssh_packet_set_log_preamble(ssh, "%suser %s", 769 authctxt->valid ? "authenticating" : "invalid ", authctxt->user); 770 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0) 771 fatal_fr(r, "assemble options"); 772 773 #define M_CP_STROPT(x) do { \ 774 if (options.x != NULL && \ 775 (r = sshbuf_put_cstring(m, options.x)) != 0) \ 776 fatal_fr(r, "assemble %s", #x); \ 777 } while (0) 778 #define M_CP_STRARRAYOPT(x, nx) do { \ 779 for (i = 0; i < options.nx; i++) { \ 780 if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \ 781 fatal_fr(r, "assemble %s", #x); \ 782 } \ 783 } while (0) 784 /* See comment in servconf.h */ 785 COPY_MATCH_STRING_OPTS(); 786 #undef M_CP_STROPT 787 #undef M_CP_STRARRAYOPT 788 789 /* Create valid auth method lists */ 790 if (auth2_setup_methods_lists(authctxt) != 0) { 791 /* 792 * The monitor will continue long enough to let the child 793 * run to it's packet_disconnect(), but it must not allow any 794 * authentication to succeed. 795 */ 796 debug_f("no valid authentication method lists"); 797 } 798 799 debug3_f("sending MONITOR_ANS_PWNAM: %d", allowed); 800 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 801 802 /* Allow service/style information on the auth context */ 803 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 804 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 805 806 #ifdef USE_PAM 807 if (options.use_pam) 808 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); 809 #endif 810 811 return (0); 812 } 813 814 int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m) 815 { 816 char *banner; 817 int r; 818 819 sshbuf_reset(m); 820 banner = auth2_read_banner(); 821 if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0) 822 fatal_fr(r, "assemble"); 823 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 824 free(banner); 825 826 return (0); 827 } 828 829 int 830 mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m) 831 { 832 int r; 833 834 monitor_permit_authentications(1); 835 836 if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 || 837 (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0) 838 fatal_fr(r, "parse"); 839 debug3_f("service=%s, style=%s", authctxt->service, authctxt->style); 840 841 if (strlen(authctxt->style) == 0) { 842 free(authctxt->style); 843 authctxt->style = NULL; 844 } 845 846 return (0); 847 } 848 849 /* 850 * Check that the key type appears in the supplied pattern list, ignoring 851 * mismatches in the signature algorithm. (Signature algorithm checks are 852 * performed in the unprivileged authentication code). 853 * Returns 1 on success, 0 otherwise. 854 */ 855 static int 856 key_base_type_match(const char *method, const struct sshkey *key, 857 const char *list) 858 { 859 char *s, *l, *ol = xstrdup(list); 860 int found = 0; 861 862 l = ol; 863 for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) { 864 if (sshkey_type_from_name(s) == key->type) { 865 found = 1; 866 break; 867 } 868 } 869 if (!found) { 870 error("%s key type %s is not in permitted list %s", method, 871 sshkey_ssh_name(key), list); 872 } 873 874 free(ol); 875 return found; 876 } 877 878 int 879 mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m) 880 { 881 static int call_count; 882 char *passwd; 883 int r, authenticated; 884 size_t plen; 885 886 if (!options.password_authentication) 887 fatal_f("password authentication not enabled"); 888 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0) 889 fatal_fr(r, "parse"); 890 /* Only authenticate if the context is valid */ 891 authenticated = options.password_authentication && 892 auth_password(ssh, passwd); 893 freezero(passwd, plen); 894 895 sshbuf_reset(m); 896 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 897 fatal_fr(r, "assemble"); 898 #ifdef USE_PAM 899 if ((r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0) 900 fatal_fr(r, "assemble PAM"); 901 #endif 902 903 debug3("%s: sending result %d", __func__, authenticated); 904 debug3_f("sending result %d", authenticated); 905 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 906 907 call_count++; 908 if (plen == 0 && call_count == 1) 909 auth_method = "none"; 910 else 911 auth_method = "password"; 912 913 /* Causes monitor loop to terminate if authenticated */ 914 return (authenticated); 915 } 916 917 #ifdef BSD_AUTH 918 int 919 mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m) 920 { 921 char *name, *infotxt; 922 u_int numprompts, *echo_on, success; 923 char **prompts; 924 int r; 925 926 if (!options.kbd_interactive_authentication) 927 fatal_f("kbd-int authentication not enabled"); 928 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 929 &prompts, &echo_on) < 0 ? 0 : 1; 930 931 sshbuf_reset(m); 932 if ((r = sshbuf_put_u32(m, success)) != 0) 933 fatal_fr(r, "assemble"); 934 if (success) { 935 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0) 936 fatal_fr(r, "assemble prompt"); 937 } 938 939 debug3_f("sending challenge success: %u", success); 940 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 941 942 if (success) { 943 free(name); 944 free(infotxt); 945 free(prompts); 946 free(echo_on); 947 } 948 949 return (0); 950 } 951 952 int 953 mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m) 954 { 955 char *response; 956 int r, authok; 957 958 if (!options.kbd_interactive_authentication) 959 fatal_f("kbd-int authentication not enabled"); 960 if (authctxt->as == NULL) 961 fatal_f("no bsd auth session"); 962 963 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 964 fatal_fr(r, "parse"); 965 authok = options.kbd_interactive_authentication && 966 auth_userresponse(authctxt->as, response, 0); 967 authctxt->as = NULL; 968 debug3_f("<%s> = <%d>", response, authok); 969 free(response); 970 971 sshbuf_reset(m); 972 if ((r = sshbuf_put_u32(m, authok)) != 0) 973 fatal_fr(r, "assemble"); 974 975 debug3_f("sending authenticated: %d", authok); 976 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 977 978 auth_method = "keyboard-interactive"; 979 auth_submethod = "bsdauth"; 980 981 return (authok != 0); 982 } 983 #endif 984 985 #ifdef USE_PAM 986 int 987 mm_answer_pam_start(struct ssh *ssh, int sock, struct sshbuf *m) 988 { 989 if (!options.use_pam) 990 fatal("UsePAM not set, but ended up in %s anyway", __func__); 991 992 start_pam(ssh); 993 994 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); 995 if (options.kbd_interactive_authentication) 996 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 997 998 return (0); 999 } 1000 1001 int 1002 mm_answer_pam_account(struct ssh *ssh, int sock, struct sshbuf *m) 1003 { 1004 u_int ret; 1005 int r; 1006 1007 if (!options.use_pam) 1008 fatal("%s: PAM not enabled", __func__); 1009 1010 ret = do_pam_account(); 1011 1012 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1013 (r = sshbuf_put_stringb(m, loginmsg)) != 0) 1014 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1015 1016 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m); 1017 1018 return (ret); 1019 } 1020 1021 static void *sshpam_ctxt, *sshpam_authok; 1022 extern KbdintDevice sshpam_device; 1023 1024 int 1025 mm_answer_pam_init_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1026 { 1027 u_int ok = 0; 1028 int r; 1029 1030 debug3("%s", __func__); 1031 if (!options.kbd_interactive_authentication) 1032 fatal("%s: kbd-int authentication not enabled", __func__); 1033 if (sshpam_ctxt != NULL) 1034 fatal("%s: already called", __func__); 1035 sshpam_ctxt = (sshpam_device.init_ctx)(authctxt); 1036 sshpam_authok = NULL; 1037 sshbuf_reset(m); 1038 if (sshpam_ctxt != NULL) { 1039 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 1040 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_QUERY, 1); 1041 ok = 1; 1042 } 1043 if ((r = sshbuf_put_u32(m, ok)) != 0) 1044 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1045 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); 1046 return (0); 1047 } 1048 1049 int 1050 mm_answer_pam_query(struct ssh *ssh, int sock, struct sshbuf *m) 1051 { 1052 char *name = NULL, *info = NULL, **prompts = NULL; 1053 u_int i, num = 0, *echo_on = 0; 1054 int r, ret; 1055 1056 debug3("%s", __func__); 1057 sshpam_authok = NULL; 1058 if (sshpam_ctxt == NULL) 1059 fatal("%s: no context", __func__); 1060 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, 1061 &num, &prompts, &echo_on); 1062 if (ret == 0 && num == 0) 1063 sshpam_authok = sshpam_ctxt; 1064 if (num > 1 || name == NULL || info == NULL) 1065 fatal("sshpam_device.query failed"); 1066 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_RESPOND, 1); 1067 sshbuf_reset(m); 1068 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1069 (r = sshbuf_put_cstring(m, name)) != 0 || 1070 (r = sshbuf_put_cstring(m, info)) != 0 || 1071 (r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0 || 1072 (r = sshbuf_put_u32(m, num)) != 0) 1073 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1074 free(name); 1075 free(info); 1076 for (i = 0; i < num; ++i) { 1077 if ((r = sshbuf_put_cstring(m, prompts[i])) != 0 || 1078 (r = sshbuf_put_u32(m, echo_on[i])) != 0) 1079 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1080 free(prompts[i]); 1081 } 1082 free(prompts); 1083 free(echo_on); 1084 auth_method = "keyboard-interactive"; 1085 auth_submethod = "pam"; 1086 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m); 1087 return (0); 1088 } 1089 1090 int 1091 mm_answer_pam_respond(struct ssh *ssh, int sock, struct sshbuf *m) 1092 { 1093 char **resp; 1094 u_int i, num; 1095 int r, ret; 1096 1097 debug3("%s", __func__); 1098 if (sshpam_ctxt == NULL) 1099 fatal("%s: no context", __func__); 1100 sshpam_authok = NULL; 1101 if ((r = sshbuf_get_u32(m, &num)) != 0) 1102 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1103 if (num > 0) { 1104 resp = xcalloc(num, sizeof(char *)); 1105 for (i = 0; i < num; ++i) { 1106 if ((r = sshbuf_get_cstring(m, &(resp[i]), NULL)) != 0) 1107 fatal("%s: buffer error: %s", 1108 __func__, ssh_err(r)); 1109 } 1110 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp); 1111 for (i = 0; i < num; ++i) 1112 free(resp[i]); 1113 free(resp); 1114 } else { 1115 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL); 1116 } 1117 sshbuf_reset(m); 1118 if ((r = sshbuf_put_u32(m, ret)) != 0) 1119 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1120 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m); 1121 auth_method = "keyboard-interactive"; 1122 auth_submethod = "pam"; 1123 if (ret == 0) 1124 sshpam_authok = sshpam_ctxt; 1125 return (0); 1126 } 1127 1128 int 1129 mm_answer_pam_free_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1130 { 1131 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt; 1132 1133 debug3("%s", __func__); 1134 if (sshpam_ctxt == NULL) 1135 fatal("%s: no context", __func__); 1136 (sshpam_device.free_ctx)(sshpam_ctxt); 1137 sshpam_ctxt = sshpam_authok = NULL; 1138 sshbuf_reset(m); 1139 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); 1140 /* Allow another attempt */ 1141 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 1142 auth_method = "keyboard-interactive"; 1143 auth_submethod = "pam"; 1144 return r; 1145 } 1146 #endif 1147 1148 int 1149 mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m) 1150 { 1151 struct sshkey *key = NULL; 1152 char *cuser, *chost; 1153 u_int pubkey_auth_attempt; 1154 u_int type = 0; 1155 int r, allowed = 0; 1156 struct sshauthopt *opts = NULL; 1157 1158 debug3_f("entering"); 1159 if ((r = sshbuf_get_u32(m, &type)) != 0 || 1160 (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 || 1161 (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 || 1162 (r = sshkey_froms(m, &key)) != 0 || 1163 (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0) 1164 fatal_fr(r, "parse"); 1165 1166 if (key != NULL && authctxt->valid) { 1167 /* These should not make it past the privsep child */ 1168 if (sshkey_type_plain(key->type) == KEY_RSA && 1169 (ssh->compat & SSH_BUG_RSASIGMD5) != 0) 1170 fatal_f("passed a SSH_BUG_RSASIGMD5 key"); 1171 1172 switch (type) { 1173 case MM_USERKEY: 1174 auth_method = "publickey"; 1175 if (!options.pubkey_authentication) 1176 break; 1177 if (auth2_key_already_used(authctxt, key)) 1178 break; 1179 if (!key_base_type_match(auth_method, key, 1180 options.pubkey_accepted_algos)) 1181 break; 1182 allowed = user_key_allowed(ssh, authctxt->pw, key, 1183 pubkey_auth_attempt, &opts); 1184 break; 1185 case MM_HOSTKEY: 1186 auth_method = "hostbased"; 1187 if (!options.hostbased_authentication) 1188 break; 1189 if (auth2_key_already_used(authctxt, key)) 1190 break; 1191 if (!key_base_type_match(auth_method, key, 1192 options.hostbased_accepted_algos)) 1193 break; 1194 allowed = hostbased_key_allowed(ssh, authctxt->pw, 1195 cuser, chost, key); 1196 auth2_record_info(authctxt, 1197 "client user \"%.100s\", client host \"%.100s\"", 1198 cuser, chost); 1199 break; 1200 default: 1201 fatal_f("unknown key type %u", type); 1202 break; 1203 } 1204 } 1205 1206 debug3_f("%s authentication%s: %s key is %s", auth_method, 1207 pubkey_auth_attempt ? "" : " test", 1208 (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key), 1209 allowed ? "allowed" : "not allowed"); 1210 1211 auth2_record_key(authctxt, 0, key); 1212 1213 /* clear temporarily storage (used by verify) */ 1214 monitor_reset_key_state(); 1215 1216 if (allowed) { 1217 /* Save temporarily for comparison in verify */ 1218 if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0) 1219 fatal_fr(r, "sshkey_to_blob"); 1220 key_blobtype = type; 1221 key_opts = opts; 1222 hostbased_cuser = cuser; 1223 hostbased_chost = chost; 1224 } else { 1225 /* Log failed attempt */ 1226 auth_log(ssh, 0, 0, auth_method, NULL); 1227 free(cuser); 1228 free(chost); 1229 } 1230 sshkey_free(key); 1231 1232 sshbuf_reset(m); 1233 if ((r = sshbuf_put_u32(m, allowed)) != 0) 1234 fatal_fr(r, "assemble"); 1235 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0) 1236 fatal_fr(r, "sshauthopt_serialise"); 1237 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 1238 1239 if (!allowed) 1240 sshauthopt_free(opts); 1241 1242 return (0); 1243 } 1244 1245 static int 1246 monitor_valid_userblob(struct ssh *ssh, const u_char *data, u_int datalen) 1247 { 1248 struct sshbuf *b; 1249 const u_char *p; 1250 char *userstyle, *cp; 1251 size_t len; 1252 u_char type; 1253 int r, fail = 0; 1254 1255 if ((b = sshbuf_from(data, datalen)) == NULL) 1256 fatal_f("sshbuf_from"); 1257 1258 if (ssh->compat & SSH_OLD_SESSIONID) { 1259 p = sshbuf_ptr(b); 1260 len = sshbuf_len(b); 1261 if ((session_id2 == NULL) || 1262 (len < session_id2_len) || 1263 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1264 fail++; 1265 if ((r = sshbuf_consume(b, session_id2_len)) != 0) 1266 fatal_fr(r, "consume"); 1267 } else { 1268 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1269 fatal_fr(r, "parse sessionid"); 1270 if ((session_id2 == NULL) || 1271 (len != session_id2_len) || 1272 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1273 fail++; 1274 } 1275 if ((r = sshbuf_get_u8(b, &type)) != 0) 1276 fatal_fr(r, "parse type"); 1277 if (type != SSH2_MSG_USERAUTH_REQUEST) 1278 fail++; 1279 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1280 fatal_fr(r, "parse userstyle"); 1281 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1282 authctxt->style ? ":" : "", 1283 authctxt->style ? authctxt->style : ""); 1284 if (strcmp(userstyle, cp) != 0) { 1285 logit("wrong user name passed to monitor: " 1286 "expected %s != %.100s", userstyle, cp); 1287 fail++; 1288 } 1289 free(userstyle); 1290 free(cp); 1291 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1292 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1293 fatal_fr(r, "parse method"); 1294 if (strcmp("publickey", cp) != 0) 1295 fail++; 1296 free(cp); 1297 if ((r = sshbuf_get_u8(b, &type)) != 0) 1298 fatal_fr(r, "parse pktype"); 1299 if (type == 0) 1300 fail++; 1301 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1302 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1303 fatal_fr(r, "parse pk"); 1304 if (sshbuf_len(b) != 0) 1305 fail++; 1306 sshbuf_free(b); 1307 return (fail == 0); 1308 } 1309 1310 static int 1311 monitor_valid_hostbasedblob(const u_char *data, u_int datalen, 1312 const char *cuser, const char *chost) 1313 { 1314 struct sshbuf *b; 1315 const u_char *p; 1316 char *cp, *userstyle; 1317 size_t len; 1318 int r, fail = 0; 1319 u_char type; 1320 1321 if ((b = sshbuf_from(data, datalen)) == NULL) 1322 fatal_f("sshbuf_new"); 1323 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1324 fatal_fr(r, "parse sessionid"); 1325 1326 if ((session_id2 == NULL) || 1327 (len != session_id2_len) || 1328 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1329 fail++; 1330 1331 if ((r = sshbuf_get_u8(b, &type)) != 0) 1332 fatal_fr(r, "parse type"); 1333 if (type != SSH2_MSG_USERAUTH_REQUEST) 1334 fail++; 1335 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1336 fatal_fr(r, "parse userstyle"); 1337 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1338 authctxt->style ? ":" : "", 1339 authctxt->style ? authctxt->style : ""); 1340 if (strcmp(userstyle, cp) != 0) { 1341 logit("wrong user name passed to monitor: " 1342 "expected %s != %.100s", userstyle, cp); 1343 fail++; 1344 } 1345 free(userstyle); 1346 free(cp); 1347 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1348 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1349 fatal_fr(r, "parse method"); 1350 if (strcmp(cp, "hostbased") != 0) 1351 fail++; 1352 free(cp); 1353 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1354 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1355 fatal_fr(r, "parse pk"); 1356 1357 /* verify client host, strip trailing dot if necessary */ 1358 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1359 fatal_fr(r, "parse host"); 1360 if (((len = strlen(cp)) > 0) && cp[len - 1] == '.') 1361 cp[len - 1] = '\0'; 1362 if (strcmp(cp, chost) != 0) 1363 fail++; 1364 free(cp); 1365 1366 /* verify client user */ 1367 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1368 fatal_fr(r, "parse ruser"); 1369 if (strcmp(cp, cuser) != 0) 1370 fail++; 1371 free(cp); 1372 1373 if (sshbuf_len(b) != 0) 1374 fail++; 1375 sshbuf_free(b); 1376 return (fail == 0); 1377 } 1378 1379 int 1380 mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m) 1381 { 1382 struct sshkey *key; 1383 const u_char *signature, *data, *blob; 1384 char *sigalg = NULL, *fp = NULL; 1385 size_t signaturelen, datalen, bloblen; 1386 int r, ret, req_presence = 0, req_verify = 0, valid_data = 0; 1387 int encoded_ret; 1388 struct sshkey_sig_details *sig_details = NULL; 1389 1390 if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 || 1391 (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 || 1392 (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 || 1393 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0) 1394 fatal_fr(r, "parse"); 1395 1396 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1397 !monitor_allowed_key(blob, bloblen)) 1398 fatal_f("bad key, not previously allowed"); 1399 1400 /* Empty signature algorithm means NULL. */ 1401 if (*sigalg == '\0') { 1402 free(sigalg); 1403 sigalg = NULL; 1404 } 1405 1406 /* XXX use sshkey_froms here; need to change key_blob, etc. */ 1407 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0) 1408 fatal_fr(r, "parse key"); 1409 1410 switch (key_blobtype) { 1411 case MM_USERKEY: 1412 valid_data = monitor_valid_userblob(ssh, data, datalen); 1413 auth_method = "publickey"; 1414 break; 1415 case MM_HOSTKEY: 1416 valid_data = monitor_valid_hostbasedblob(data, datalen, 1417 hostbased_cuser, hostbased_chost); 1418 auth_method = "hostbased"; 1419 break; 1420 default: 1421 valid_data = 0; 1422 break; 1423 } 1424 if (!valid_data) 1425 fatal_f("bad %s signature data blob", 1426 key_blobtype == MM_USERKEY ? "userkey" : 1427 (key_blobtype == MM_HOSTKEY ? "hostkey" : "unknown")); 1428 1429 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 1430 SSH_FP_DEFAULT)) == NULL) 1431 fatal_f("sshkey_fingerprint failed"); 1432 1433 ret = sshkey_verify(key, signature, signaturelen, data, datalen, 1434 sigalg, ssh->compat, &sig_details); 1435 debug3_f("%s %s signature %s%s%s", auth_method, sshkey_type(key), 1436 (ret == 0) ? "verified" : "unverified", 1437 (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : ""); 1438 1439 if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) { 1440 req_presence = (options.pubkey_auth_options & 1441 PUBKEYAUTH_TOUCH_REQUIRED) || 1442 !key_opts->no_require_user_presence; 1443 if (req_presence && 1444 (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) { 1445 error("public key %s %s signature for %s%s from %.128s " 1446 "port %d rejected: user presence " 1447 "(authenticator touch) requirement not met ", 1448 sshkey_type(key), fp, 1449 authctxt->valid ? "" : "invalid user ", 1450 authctxt->user, ssh_remote_ipaddr(ssh), 1451 ssh_remote_port(ssh)); 1452 ret = SSH_ERR_SIGNATURE_INVALID; 1453 } 1454 req_verify = (options.pubkey_auth_options & 1455 PUBKEYAUTH_VERIFY_REQUIRED) || key_opts->require_verify; 1456 if (req_verify && 1457 (sig_details->sk_flags & SSH_SK_USER_VERIFICATION_REQD) == 0) { 1458 error("public key %s %s signature for %s%s from %.128s " 1459 "port %d rejected: user verification requirement " 1460 "not met ", sshkey_type(key), fp, 1461 authctxt->valid ? "" : "invalid user ", 1462 authctxt->user, ssh_remote_ipaddr(ssh), 1463 ssh_remote_port(ssh)); 1464 ret = SSH_ERR_SIGNATURE_INVALID; 1465 } 1466 } 1467 auth2_record_key(authctxt, ret == 0, key); 1468 1469 if (key_blobtype == MM_USERKEY) 1470 auth_activate_options(ssh, key_opts); 1471 monitor_reset_key_state(); 1472 1473 sshbuf_reset(m); 1474 1475 /* encode ret != 0 as positive integer, since we're sending u32 */ 1476 encoded_ret = (ret != 0); 1477 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 || 1478 (r = sshbuf_put_u8(m, sig_details != NULL)) != 0) 1479 fatal_fr(r, "assemble"); 1480 if (sig_details != NULL) { 1481 if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 || 1482 (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0) 1483 fatal_fr(r, "assemble sk"); 1484 } 1485 sshkey_sig_details_free(sig_details); 1486 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1487 1488 free(sigalg); 1489 free(fp); 1490 sshkey_free(key); 1491 1492 return ret == 0; 1493 } 1494 1495 static void 1496 mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw) 1497 { 1498 socklen_t fromlen; 1499 struct sockaddr_storage from; 1500 1501 /* 1502 * Get IP address of client. If the connection is not a socket, let 1503 * the address be 0.0.0.0. 1504 */ 1505 memset(&from, 0, sizeof(from)); 1506 fromlen = sizeof(from); 1507 if (ssh_packet_connection_is_on_socket(ssh)) { 1508 if (getpeername(ssh_packet_get_connection_in(ssh), 1509 (struct sockaddr *)&from, &fromlen) == -1) { 1510 debug("getpeername: %.100s", strerror(errno)); 1511 cleanup_exit(255); 1512 } 1513 } 1514 /* Record that there was a login on that tty from the remote host. */ 1515 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1516 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1517 (struct sockaddr *)&from, fromlen); 1518 } 1519 1520 static void 1521 mm_session_close(Session *s) 1522 { 1523 debug3_f("session %d pid %ld", s->self, (long)s->pid); 1524 if (s->ttyfd != -1) { 1525 debug3_f("tty %s ptyfd %d", s->tty, s->ptyfd); 1526 session_pty_cleanup2(s); 1527 } 1528 session_unused(s->self); 1529 } 1530 1531 int 1532 mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m) 1533 { 1534 extern struct monitor *pmonitor; 1535 Session *s; 1536 int r, res, fd0; 1537 1538 debug3_f("entering"); 1539 1540 sshbuf_reset(m); 1541 s = session_new(); 1542 if (s == NULL) 1543 goto error; 1544 s->authctxt = authctxt; 1545 s->pw = authctxt->pw; 1546 s->pid = pmonitor->m_pid; 1547 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1548 if (res == 0) 1549 goto error; 1550 pty_setowner(authctxt->pw, s->tty); 1551 1552 if ((r = sshbuf_put_u32(m, 1)) != 0 || 1553 (r = sshbuf_put_cstring(m, s->tty)) != 0) 1554 fatal_fr(r, "assemble"); 1555 1556 /* We need to trick ttyslot */ 1557 if (dup2(s->ttyfd, 0) == -1) 1558 fatal_f("dup2"); 1559 1560 mm_record_login(ssh, s, authctxt->pw); 1561 1562 /* Now we can close the file descriptor again */ 1563 close(0); 1564 1565 /* send messages generated by record_login */ 1566 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0) 1567 fatal_fr(r, "assemble loginmsg"); 1568 sshbuf_reset(loginmsg); 1569 1570 mm_request_send(sock, MONITOR_ANS_PTY, m); 1571 1572 if (mm_send_fd(sock, s->ptyfd) == -1 || 1573 mm_send_fd(sock, s->ttyfd) == -1) 1574 fatal_f("send fds failed"); 1575 1576 /* make sure nothing uses fd 0 */ 1577 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1578 fatal_f("open(/dev/null): %s", strerror(errno)); 1579 if (fd0 != 0) 1580 error_f("fd0 %d != 0", fd0); 1581 1582 /* slave side of pty is not needed */ 1583 close(s->ttyfd); 1584 s->ttyfd = s->ptyfd; 1585 /* no need to dup() because nobody closes ptyfd */ 1586 s->ptymaster = s->ptyfd; 1587 1588 debug3_f("tty %s ptyfd %d", s->tty, s->ttyfd); 1589 1590 return (0); 1591 1592 error: 1593 if (s != NULL) 1594 mm_session_close(s); 1595 if ((r = sshbuf_put_u32(m, 0)) != 0) 1596 fatal_fr(r, "assemble 0"); 1597 mm_request_send(sock, MONITOR_ANS_PTY, m); 1598 return (0); 1599 } 1600 1601 int 1602 mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m) 1603 { 1604 Session *s; 1605 char *tty; 1606 int r; 1607 1608 debug3_f("entering"); 1609 1610 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0) 1611 fatal_fr(r, "parse tty"); 1612 if ((s = session_by_tty(tty)) != NULL) 1613 mm_session_close(s); 1614 sshbuf_reset(m); 1615 free(tty); 1616 return (0); 1617 } 1618 1619 int 1620 mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req) 1621 { 1622 extern struct monitor *pmonitor; 1623 int res, status; 1624 1625 debug3_f("tearing down sessions"); 1626 1627 /* The child is terminating */ 1628 session_destroy_all(ssh, &mm_session_close); 1629 1630 #ifdef USE_PAM 1631 if (options.use_pam) 1632 sshpam_cleanup(); 1633 #endif 1634 1635 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1636 if (errno != EINTR) 1637 exit(1); 1638 1639 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1640 1641 /* Terminate process */ 1642 exit(res); 1643 } 1644 1645 #ifdef SSH_AUDIT_EVENTS 1646 /* Report that an audit event occurred */ 1647 int 1648 mm_answer_audit_event(struct ssh *ssh, int socket, struct sshbuf *m) 1649 { 1650 u_int n; 1651 ssh_audit_event_t event; 1652 int r; 1653 1654 debug3("%s entering", __func__); 1655 1656 if ((r = sshbuf_get_u32(m, &n)) != 0) 1657 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1658 event = (ssh_audit_event_t)n; 1659 switch (event) { 1660 case SSH_AUTH_FAIL_PUBKEY: 1661 case SSH_AUTH_FAIL_HOSTBASED: 1662 case SSH_AUTH_FAIL_GSSAPI: 1663 case SSH_LOGIN_EXCEED_MAXTRIES: 1664 case SSH_LOGIN_ROOT_DENIED: 1665 case SSH_CONNECTION_CLOSE: 1666 case SSH_INVALID_USER: 1667 audit_event(ssh, event); 1668 break; 1669 default: 1670 fatal("Audit event type %d not permitted", event); 1671 } 1672 1673 return (0); 1674 } 1675 1676 int 1677 mm_answer_audit_command(struct ssh *ssh, int socket, struct sshbuf *m) 1678 { 1679 char *cmd; 1680 int r; 1681 1682 debug3("%s entering", __func__); 1683 if ((r = sshbuf_get_cstring(m, &cmd, NULL)) != 0) 1684 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1685 /* sanity check command, if so how? */ 1686 audit_run_command(cmd); 1687 free(cmd); 1688 return (0); 1689 } 1690 #endif /* SSH_AUDIT_EVENTS */ 1691 1692 void 1693 monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor) 1694 { 1695 ssh_clear_newkeys(ssh, MODE_IN); 1696 ssh_clear_newkeys(ssh, MODE_OUT); 1697 sshbuf_free(child_state); 1698 child_state = NULL; 1699 } 1700 1701 void 1702 monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor) 1703 { 1704 struct kex *kex; 1705 int r; 1706 1707 debug3_f("packet_set_state"); 1708 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1709 fatal_fr(r, "packet_set_state"); 1710 sshbuf_free(child_state); 1711 child_state = NULL; 1712 if ((kex = ssh->kex) == NULL) 1713 fatal_f("internal error: ssh->kex == NULL"); 1714 if (session_id2_len != sshbuf_len(ssh->kex->session_id)) { 1715 fatal_f("incorrect session id length %zu (expected %u)", 1716 sshbuf_len(ssh->kex->session_id), session_id2_len); 1717 } 1718 if (memcmp(sshbuf_ptr(ssh->kex->session_id), session_id2, 1719 session_id2_len) != 0) 1720 fatal_f("session ID mismatch"); 1721 /* XXX set callbacks */ 1722 #ifdef WITH_OPENSSL 1723 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server; 1724 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server; 1725 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server; 1726 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server; 1727 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server; 1728 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1729 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1730 # ifdef OPENSSL_HAS_ECC 1731 kex->kex[KEX_ECDH_SHA2] = kex_gen_server; 1732 # endif 1733 #endif /* WITH_OPENSSL */ 1734 kex->kex[KEX_C25519_SHA256] = kex_gen_server; 1735 kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server; 1736 kex->load_host_public_key=&get_hostkey_public_by_type; 1737 kex->load_host_private_key=&get_hostkey_private_by_type; 1738 kex->host_key_index=&get_hostkey_index; 1739 kex->sign = sshd_hostkey_sign; 1740 } 1741 1742 /* This function requires careful sanity checking */ 1743 1744 void 1745 mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor) 1746 { 1747 debug3_f("Waiting for new keys"); 1748 1749 if ((child_state = sshbuf_new()) == NULL) 1750 fatal_f("sshbuf_new failed"); 1751 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1752 child_state); 1753 debug3_f("GOT new keys"); 1754 } 1755 1756 1757 /* XXX */ 1758 1759 #define FD_CLOSEONEXEC(x) do { \ 1760 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1761 fatal("fcntl(%d, F_SETFD)", x); \ 1762 } while (0) 1763 1764 static void 1765 monitor_openfds(struct monitor *mon, int do_logfds) 1766 { 1767 int pair[2]; 1768 #ifdef SO_ZEROIZE 1769 int on = 1; 1770 #endif 1771 1772 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1773 fatal_f("socketpair: %s", strerror(errno)); 1774 #ifdef SO_ZEROIZE 1775 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1776 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno)); 1777 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1778 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno)); 1779 #endif 1780 FD_CLOSEONEXEC(pair[0]); 1781 FD_CLOSEONEXEC(pair[1]); 1782 mon->m_recvfd = pair[0]; 1783 mon->m_sendfd = pair[1]; 1784 1785 if (do_logfds) { 1786 if (pipe(pair) == -1) 1787 fatal_f("pipe: %s", strerror(errno)); 1788 FD_CLOSEONEXEC(pair[0]); 1789 FD_CLOSEONEXEC(pair[1]); 1790 mon->m_log_recvfd = pair[0]; 1791 mon->m_log_sendfd = pair[1]; 1792 } else 1793 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1794 } 1795 1796 #define MM_MEMSIZE 65536 1797 1798 struct monitor * 1799 monitor_init(void) 1800 { 1801 struct monitor *mon; 1802 1803 mon = xcalloc(1, sizeof(*mon)); 1804 monitor_openfds(mon, 1); 1805 1806 return mon; 1807 } 1808 1809 void 1810 monitor_reinit(struct monitor *mon) 1811 { 1812 monitor_openfds(mon, 0); 1813 } 1814 1815 #ifdef GSSAPI 1816 int 1817 mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1818 { 1819 gss_OID_desc goid; 1820 OM_uint32 major; 1821 size_t len; 1822 u_char *p; 1823 int r; 1824 1825 if (!options.gss_authentication) 1826 fatal_f("GSSAPI authentication not enabled"); 1827 1828 if ((r = sshbuf_get_string(m, &p, &len)) != 0) 1829 fatal_fr(r, "parse"); 1830 goid.elements = p; 1831 goid.length = len; 1832 1833 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1834 1835 free(goid.elements); 1836 1837 sshbuf_reset(m); 1838 if ((r = sshbuf_put_u32(m, major)) != 0) 1839 fatal_fr(r, "assemble"); 1840 1841 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1842 1843 /* Now we have a context, enable the step */ 1844 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1845 1846 return (0); 1847 } 1848 1849 int 1850 mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1851 { 1852 gss_buffer_desc in; 1853 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1854 OM_uint32 major, minor; 1855 OM_uint32 flags = 0; /* GSI needs this */ 1856 int r; 1857 1858 if (!options.gss_authentication) 1859 fatal_f("GSSAPI authentication not enabled"); 1860 1861 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0) 1862 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1863 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1864 free(in.value); 1865 1866 sshbuf_reset(m); 1867 if ((r = sshbuf_put_u32(m, major)) != 0 || 1868 (r = sshbuf_put_string(m, out.value, out.length)) != 0 || 1869 (r = sshbuf_put_u32(m, flags)) != 0) 1870 fatal_fr(r, "assemble"); 1871 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1872 1873 gss_release_buffer(&minor, &out); 1874 1875 if (major == GSS_S_COMPLETE) { 1876 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1877 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1878 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1879 } 1880 return (0); 1881 } 1882 1883 int 1884 mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m) 1885 { 1886 gss_buffer_desc gssbuf, mic; 1887 OM_uint32 ret; 1888 int r; 1889 1890 if (!options.gss_authentication) 1891 fatal_f("GSSAPI authentication not enabled"); 1892 1893 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 || 1894 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0) 1895 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1896 1897 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1898 1899 free(gssbuf.value); 1900 free(mic.value); 1901 1902 sshbuf_reset(m); 1903 if ((r = sshbuf_put_u32(m, ret)) != 0) 1904 fatal_fr(r, "assemble"); 1905 1906 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1907 1908 if (!GSS_ERROR(ret)) 1909 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1910 1911 return (0); 1912 } 1913 1914 int 1915 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m) 1916 { 1917 int r, authenticated; 1918 const char *displayname; 1919 1920 if (!options.gss_authentication) 1921 fatal_f("GSSAPI authentication not enabled"); 1922 1923 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1924 1925 sshbuf_reset(m); 1926 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 1927 fatal_fr(r, "assemble"); 1928 1929 debug3_f("sending result %d", authenticated); 1930 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1931 1932 auth_method = "gssapi-with-mic"; 1933 1934 if ((displayname = ssh_gssapi_displayname()) != NULL) 1935 auth2_record_info(authctxt, "%s", displayname); 1936 1937 /* Monitor loop will terminate if authenticated */ 1938 return (authenticated); 1939 } 1940 #endif /* GSSAPI */ 1941 1942