1 /* $OpenBSD: monitor.c,v 1.197 2019/01/21 10:38:54 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 99 #ifdef GSSAPI 100 static Gssctxt *gsscontext = NULL; 101 #endif 102 103 /* Imports */ 104 extern ServerOptions options; 105 extern u_int utmp_len; 106 extern u_char session_id[]; 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_skeyquery(struct ssh *, int, struct sshbuf *); 124 int mm_answer_skeyrespond(struct ssh *, int, struct sshbuf *); 125 int mm_answer_keyallowed(struct ssh *, int, struct sshbuf *); 126 int mm_answer_keyverify(struct ssh *, int, struct sshbuf *); 127 int mm_answer_pty(struct ssh *, int, struct sshbuf *); 128 int mm_answer_pty_cleanup(struct ssh *, int, struct sshbuf *); 129 int mm_answer_term(struct ssh *, int, struct sshbuf *); 130 int mm_answer_rsa_keyallowed(struct ssh *, int, struct sshbuf *); 131 int mm_answer_rsa_challenge(struct ssh *, int, struct sshbuf *); 132 int mm_answer_rsa_response(struct ssh *, int, struct sshbuf *); 133 int mm_answer_sesskey(struct ssh *, int, struct sshbuf *); 134 int mm_answer_sessid(struct ssh *, int, struct sshbuf *); 135 136 #ifdef USE_PAM 137 int mm_answer_pam_start(struct ssh *, int, struct sshbuf *); 138 int mm_answer_pam_account(struct ssh *, int, struct sshbuf *); 139 int mm_answer_pam_init_ctx(struct ssh *, int, struct sshbuf *); 140 int mm_answer_pam_query(struct ssh *, int, struct sshbuf *); 141 int mm_answer_pam_respond(struct ssh *, int, struct sshbuf *); 142 int mm_answer_pam_free_ctx(struct ssh *, int, struct sshbuf *); 143 #endif 144 145 #ifdef GSSAPI 146 int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *); 147 int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *); 148 int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *); 149 int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *); 150 #endif 151 152 #ifdef SSH_AUDIT_EVENTS 153 int mm_answer_audit_event(struct ssh *, int, struct sshbuf *); 154 int mm_answer_audit_command(struct ssh *, int, struct sshbuf *); 155 #endif 156 157 static Authctxt *authctxt; 158 159 /* local state for key verify */ 160 static u_char *key_blob = NULL; 161 static size_t key_bloblen = 0; 162 static int key_blobtype = MM_NOKEY; 163 static struct sshauthopt *key_opts = NULL; 164 static char *hostbased_cuser = NULL; 165 static char *hostbased_chost = NULL; 166 static char *auth_method = "unknown"; 167 static char *auth_submethod = NULL; 168 static u_int session_id2_len = 0; 169 static u_char *session_id2 = NULL; 170 static pid_t monitor_child_pid; 171 172 struct mon_table { 173 enum monitor_reqtype type; 174 int flags; 175 int (*f)(struct ssh *, int, struct sshbuf *); 176 }; 177 178 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 179 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 180 #define MON_ONCE 0x0010 /* Disable after calling */ 181 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 182 183 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 184 185 #define MON_PERMIT 0x1000 /* Request is permitted */ 186 187 static int monitor_read(struct ssh *, struct monitor *, struct mon_table *, 188 struct mon_table **); 189 static int monitor_read_log(struct monitor *); 190 191 struct mon_table mon_dispatch_proto20[] = { 192 #ifdef WITH_OPENSSL 193 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 194 #endif 195 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 196 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 197 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 198 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 199 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 200 #ifdef USE_PAM 201 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 202 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 203 {MONITOR_REQ_PAM_INIT_CTX, MON_ONCE, mm_answer_pam_init_ctx}, 204 {MONITOR_REQ_PAM_QUERY, 0, mm_answer_pam_query}, 205 {MONITOR_REQ_PAM_RESPOND, MON_ONCE, mm_answer_pam_respond}, 206 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 207 #endif 208 #ifdef SSH_AUDIT_EVENTS 209 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 210 #endif 211 #ifdef BSD_AUTH 212 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 213 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 214 #endif 215 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 216 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 217 #ifdef GSSAPI 218 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 219 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx}, 220 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok}, 221 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic}, 222 #endif 223 {0, 0, NULL} 224 }; 225 226 struct mon_table mon_dispatch_postauth20[] = { 227 #ifdef WITH_OPENSSL 228 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 229 #endif 230 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 231 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 232 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 233 {MONITOR_REQ_TERM, 0, mm_answer_term}, 234 #ifdef SSH_AUDIT_EVENTS 235 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 236 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command}, 237 #endif 238 {0, 0, NULL} 239 }; 240 241 struct mon_table *mon_dispatch; 242 243 /* Specifies if a certain message is allowed at the moment */ 244 static void 245 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 246 { 247 while (ent->f != NULL) { 248 if (ent->type == type) { 249 ent->flags &= ~MON_PERMIT; 250 ent->flags |= permit ? MON_PERMIT : 0; 251 return; 252 } 253 ent++; 254 } 255 } 256 257 static void 258 monitor_permit_authentications(int permit) 259 { 260 struct mon_table *ent = mon_dispatch; 261 262 while (ent->f != NULL) { 263 if (ent->flags & MON_AUTH) { 264 ent->flags &= ~MON_PERMIT; 265 ent->flags |= permit ? MON_PERMIT : 0; 266 } 267 ent++; 268 } 269 } 270 271 void 272 monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor) 273 { 274 struct mon_table *ent; 275 int authenticated = 0, partial = 0; 276 277 debug3("preauth child monitor started"); 278 279 if (pmonitor->m_recvfd >= 0) 280 close(pmonitor->m_recvfd); 281 if (pmonitor->m_log_sendfd >= 0) 282 close(pmonitor->m_log_sendfd); 283 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 284 285 authctxt = (Authctxt *)ssh->authctxt; 286 memset(authctxt, 0, sizeof(*authctxt)); 287 ssh->authctxt = authctxt; 288 289 authctxt->loginmsg = loginmsg; 290 291 mon_dispatch = mon_dispatch_proto20; 292 /* Permit requests for moduli and signatures */ 293 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 294 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 295 296 /* The first few requests do not require asynchronous access */ 297 while (!authenticated) { 298 partial = 0; 299 auth_method = "unknown"; 300 auth_submethod = NULL; 301 auth2_authctxt_reset_info(authctxt); 302 303 authenticated = (monitor_read(ssh, pmonitor, 304 mon_dispatch, &ent) == 1); 305 306 /* Special handling for multiple required authentications */ 307 if (options.num_auth_methods != 0) { 308 if (authenticated && 309 !auth2_update_methods_lists(authctxt, 310 auth_method, auth_submethod)) { 311 debug3("%s: method %s: partial", __func__, 312 auth_method); 313 authenticated = 0; 314 partial = 1; 315 } 316 } 317 318 if (authenticated) { 319 if (!(ent->flags & MON_AUTHDECIDE)) 320 fatal("%s: unexpected authentication from %d", 321 __func__, ent->type); 322 if (authctxt->pw->pw_uid == 0 && 323 !auth_root_allowed(ssh, auth_method)) 324 authenticated = 0; 325 #ifdef USE_PAM 326 /* PAM needs to perform account checks after auth */ 327 if (options.use_pam && authenticated) { 328 struct sshbuf *m; 329 330 if ((m = sshbuf_new()) == NULL) 331 fatal("%s: sshbuf_new failed", 332 __func__); 333 mm_request_receive_expect(pmonitor->m_sendfd, 334 MONITOR_REQ_PAM_ACCOUNT, m); 335 authenticated = mm_answer_pam_account( 336 ssh, pmonitor->m_sendfd, m); 337 sshbuf_free(m); 338 } 339 #endif 340 } 341 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 342 auth_log(ssh, authenticated, partial, 343 auth_method, auth_submethod); 344 if (!partial && !authenticated) 345 authctxt->failures++; 346 if (authenticated || partial) { 347 auth2_update_session_info(authctxt, 348 auth_method, auth_submethod); 349 } 350 } 351 } 352 353 if (!authctxt->valid) 354 fatal("%s: authenticated invalid user", __func__); 355 if (strcmp(auth_method, "unknown") == 0) 356 fatal("%s: authentication method name unknown", __func__); 357 358 debug("%s: %s has been authenticated by privileged process", 359 __func__, authctxt->user); 360 ssh->authctxt = NULL; 361 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 362 363 mm_get_keystate(ssh, pmonitor); 364 365 /* Drain any buffered messages from the child */ 366 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 367 ; 368 369 if (pmonitor->m_recvfd >= 0) 370 close(pmonitor->m_recvfd); 371 if (pmonitor->m_log_sendfd >= 0) 372 close(pmonitor->m_log_sendfd); 373 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 374 } 375 376 static void 377 monitor_set_child_handler(pid_t pid) 378 { 379 monitor_child_pid = pid; 380 } 381 382 static void 383 monitor_child_handler(int sig) 384 { 385 kill(monitor_child_pid, sig); 386 } 387 388 void 389 monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor) 390 { 391 close(pmonitor->m_recvfd); 392 pmonitor->m_recvfd = -1; 393 394 monitor_set_child_handler(pmonitor->m_pid); 395 signal(SIGHUP, &monitor_child_handler); 396 signal(SIGTERM, &monitor_child_handler); 397 signal(SIGINT, &monitor_child_handler); 398 #ifdef SIGXFSZ 399 signal(SIGXFSZ, SIG_IGN); 400 #endif 401 402 mon_dispatch = mon_dispatch_postauth20; 403 404 /* Permit requests for moduli and signatures */ 405 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 406 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 407 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 408 409 if (auth_opts->permit_pty_flag) { 410 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 411 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 412 } 413 414 for (;;) 415 monitor_read(ssh, pmonitor, mon_dispatch, NULL); 416 } 417 418 static int 419 monitor_read_log(struct monitor *pmonitor) 420 { 421 struct sshbuf *logmsg; 422 u_int len, level; 423 char *msg; 424 u_char *p; 425 int r; 426 427 if ((logmsg = sshbuf_new()) == NULL) 428 fatal("%s: sshbuf_new", __func__); 429 430 /* Read length */ 431 if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0) 432 fatal("%s: reserve: %s", __func__, ssh_err(r)); 433 if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) { 434 if (errno == EPIPE) { 435 sshbuf_free(logmsg); 436 debug("%s: child log fd closed", __func__); 437 close(pmonitor->m_log_recvfd); 438 pmonitor->m_log_recvfd = -1; 439 return -1; 440 } 441 fatal("%s: log fd read: %s", __func__, strerror(errno)); 442 } 443 if ((r = sshbuf_get_u32(logmsg, &len)) != 0) 444 fatal("%s: get len: %s", __func__, ssh_err(r)); 445 if (len <= 4 || len > 8192) 446 fatal("%s: invalid log message length %u", __func__, len); 447 448 /* Read severity, message */ 449 sshbuf_reset(logmsg); 450 if ((r = sshbuf_reserve(logmsg, len, &p)) != 0) 451 fatal("%s: reserve: %s", __func__, ssh_err(r)); 452 if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len) 453 fatal("%s: log fd read: %s", __func__, strerror(errno)); 454 if ((r = sshbuf_get_u32(logmsg, &level)) != 0 || 455 (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0) 456 fatal("%s: decode: %s", __func__, ssh_err(r)); 457 458 /* Log it */ 459 if (log_level_name(level) == NULL) 460 fatal("%s: invalid log level %u (corrupted message?)", 461 __func__, level); 462 do_log2(level, "%s [preauth]", msg); 463 464 sshbuf_free(logmsg); 465 free(msg); 466 467 return 0; 468 } 469 470 static int 471 monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent, 472 struct mon_table **pent) 473 { 474 struct sshbuf *m; 475 int r, ret; 476 u_char type; 477 struct pollfd pfd[2]; 478 479 for (;;) { 480 memset(&pfd, 0, sizeof(pfd)); 481 pfd[0].fd = pmonitor->m_sendfd; 482 pfd[0].events = POLLIN; 483 pfd[1].fd = pmonitor->m_log_recvfd; 484 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 485 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 486 if (errno == EINTR || errno == EAGAIN) 487 continue; 488 fatal("%s: poll: %s", __func__, strerror(errno)); 489 } 490 if (pfd[1].revents) { 491 /* 492 * Drain all log messages before processing next 493 * monitor request. 494 */ 495 monitor_read_log(pmonitor); 496 continue; 497 } 498 if (pfd[0].revents) 499 break; /* Continues below */ 500 } 501 502 if ((m = sshbuf_new()) == NULL) 503 fatal("%s: sshbuf_new", __func__); 504 505 mm_request_receive(pmonitor->m_sendfd, m); 506 if ((r = sshbuf_get_u8(m, &type)) != 0) 507 fatal("%s: decode: %s", __func__, ssh_err(r)); 508 509 debug3("%s: checking request %d", __func__, type); 510 511 while (ent->f != NULL) { 512 if (ent->type == type) 513 break; 514 ent++; 515 } 516 517 if (ent->f != NULL) { 518 if (!(ent->flags & MON_PERMIT)) 519 fatal("%s: unpermitted request %d", __func__, 520 type); 521 ret = (*ent->f)(ssh, pmonitor->m_sendfd, m); 522 sshbuf_free(m); 523 524 /* The child may use this request only once, disable it */ 525 if (ent->flags & MON_ONCE) { 526 debug2("%s: %d used once, disabling now", __func__, 527 type); 528 ent->flags &= ~MON_PERMIT; 529 } 530 531 if (pent != NULL) 532 *pent = ent; 533 534 return ret; 535 } 536 537 fatal("%s: unsupported request: %d", __func__, type); 538 539 /* NOTREACHED */ 540 return (-1); 541 } 542 543 /* allowed key state */ 544 static int 545 monitor_allowed_key(u_char *blob, u_int bloblen) 546 { 547 /* make sure key is allowed */ 548 if (key_blob == NULL || key_bloblen != bloblen || 549 timingsafe_bcmp(key_blob, blob, key_bloblen)) 550 return (0); 551 return (1); 552 } 553 554 static void 555 monitor_reset_key_state(void) 556 { 557 /* reset state */ 558 free(key_blob); 559 free(hostbased_cuser); 560 free(hostbased_chost); 561 sshauthopt_free(key_opts); 562 key_blob = NULL; 563 key_bloblen = 0; 564 key_blobtype = MM_NOKEY; 565 key_opts = NULL; 566 hostbased_cuser = NULL; 567 hostbased_chost = NULL; 568 } 569 570 #ifdef WITH_OPENSSL 571 int 572 mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m) 573 { 574 DH *dh; 575 const BIGNUM *dh_p, *dh_g; 576 int r; 577 u_int min, want, max; 578 579 if ((r = sshbuf_get_u32(m, &min)) != 0 || 580 (r = sshbuf_get_u32(m, &want)) != 0 || 581 (r = sshbuf_get_u32(m, &max)) != 0) 582 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 583 584 debug3("%s: got parameters: %d %d %d", 585 __func__, min, want, max); 586 /* We need to check here, too, in case the child got corrupted */ 587 if (max < min || want < min || max < want) 588 fatal("%s: bad parameters: %d %d %d", 589 __func__, min, want, max); 590 591 sshbuf_reset(m); 592 593 dh = choose_dh(min, want, max); 594 if (dh == NULL) { 595 if ((r = sshbuf_put_u8(m, 0)) != 0) 596 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 597 return (0); 598 } else { 599 /* Send first bignum */ 600 DH_get0_pqg(dh, &dh_p, NULL, &dh_g); 601 if ((r = sshbuf_put_u8(m, 1)) != 0 || 602 (r = sshbuf_put_bignum2(m, dh_p)) != 0 || 603 (r = sshbuf_put_bignum2(m, dh_g)) != 0) 604 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 605 606 DH_free(dh); 607 } 608 mm_request_send(sock, MONITOR_ANS_MODULI, m); 609 return (0); 610 } 611 #endif 612 613 int 614 mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m) 615 { 616 extern int auth_sock; /* XXX move to state struct? */ 617 struct sshkey *key; 618 struct sshbuf *sigbuf = NULL; 619 u_char *p = NULL, *signature = NULL; 620 char *alg = NULL; 621 size_t datlen, siglen, alglen; 622 int r, is_proof = 0; 623 u_int keyid, compat; 624 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 625 626 debug3("%s", __func__); 627 628 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 629 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 630 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0 || 631 (r = sshbuf_get_u32(m, &compat)) != 0) 632 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 633 if (keyid > INT_MAX) 634 fatal("%s: invalid key ID", __func__); 635 636 /* 637 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 638 * SHA384 (48 bytes) and SHA512 (64 bytes). 639 * 640 * Otherwise, verify the signature request is for a hostkey 641 * proof. 642 * 643 * XXX perform similar check for KEX signature requests too? 644 * it's not trivial, since what is signed is the hash, rather 645 * than the full kex structure... 646 */ 647 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 648 /* 649 * Construct expected hostkey proof and compare it to what 650 * the client sent us. 651 */ 652 if (session_id2_len == 0) /* hostkeys is never first */ 653 fatal("%s: bad data length: %zu", __func__, datlen); 654 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 655 fatal("%s: no hostkey for index %d", __func__, keyid); 656 if ((sigbuf = sshbuf_new()) == NULL) 657 fatal("%s: sshbuf_new", __func__); 658 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 659 (r = sshbuf_put_string(sigbuf, session_id2, 660 session_id2_len)) != 0 || 661 (r = sshkey_puts(key, sigbuf)) != 0) 662 fatal("%s: couldn't prepare private key " 663 "proof buffer: %s", __func__, ssh_err(r)); 664 if (datlen != sshbuf_len(sigbuf) || 665 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 666 fatal("%s: bad data length: %zu, hostkey proof len %zu", 667 __func__, datlen, sshbuf_len(sigbuf)); 668 sshbuf_free(sigbuf); 669 is_proof = 1; 670 } 671 672 /* save session id, it will be passed on the first call */ 673 if (session_id2_len == 0) { 674 session_id2_len = datlen; 675 session_id2 = xmalloc(session_id2_len); 676 memcpy(session_id2, p, session_id2_len); 677 } 678 679 if ((key = get_hostkey_by_index(keyid)) != NULL) { 680 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 681 compat)) != 0) 682 fatal("%s: sshkey_sign failed: %s", 683 __func__, ssh_err(r)); 684 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 685 auth_sock > 0) { 686 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 687 p, datlen, alg, compat)) != 0) { 688 fatal("%s: ssh_agent_sign failed: %s", 689 __func__, ssh_err(r)); 690 } 691 } else 692 fatal("%s: no hostkey from index %d", __func__, keyid); 693 694 debug3("%s: %s signature %p(%zu)", __func__, 695 is_proof ? "KEX" : "hostkey proof", signature, siglen); 696 697 sshbuf_reset(m); 698 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 699 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 700 701 free(alg); 702 free(p); 703 free(signature); 704 705 mm_request_send(sock, MONITOR_ANS_SIGN, m); 706 707 /* Turn on permissions for getpwnam */ 708 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 709 710 return (0); 711 } 712 713 /* Retrieves the password entry and also checks if the user is permitted */ 714 715 int 716 mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m) 717 { 718 char *username; 719 struct passwd *pwent; 720 int r, allowed = 0; 721 u_int i; 722 723 debug3("%s", __func__); 724 725 if (authctxt->attempt++ != 0) 726 fatal("%s: multiple attempts for getpwnam", __func__); 727 728 if ((r = sshbuf_get_cstring(m, &username, NULL)) != 0) 729 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 730 731 pwent = getpwnamallow(ssh, username); 732 733 authctxt->user = xstrdup(username); 734 setproctitle("%s [priv]", pwent ? username : "unknown"); 735 free(username); 736 737 sshbuf_reset(m); 738 739 if (pwent == NULL) { 740 if ((r = sshbuf_put_u8(m, 0)) != 0) 741 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 742 authctxt->pw = fakepw(); 743 goto out; 744 } 745 746 allowed = 1; 747 authctxt->pw = pwent; 748 authctxt->valid = 1; 749 750 /* XXX don't sent pwent to unpriv; send fake class/dir/shell too */ 751 if ((r = sshbuf_put_u8(m, 1)) != 0 || 752 (r = sshbuf_put_string(m, pwent, sizeof(*pwent))) != 0 || 753 (r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || 754 (r = sshbuf_put_cstring(m, "*")) != 0 || 755 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS 756 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 || 757 #endif 758 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS 759 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 || 760 #endif 761 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 || 762 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0) 763 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 764 765 out: 766 ssh_packet_set_log_preamble(ssh, "%suser %s", 767 authctxt->valid ? "authenticating" : "invalid ", authctxt->user); 768 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0) 769 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 770 771 #define M_CP_STROPT(x) do { \ 772 if (options.x != NULL) { \ 773 if ((r = sshbuf_put_cstring(m, options.x)) != 0) \ 774 fatal("%s: buffer error: %s", \ 775 __func__, ssh_err(r)); \ 776 } \ 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("%s: buffer error: %s", \ 782 __func__, ssh_err(r)); \ 783 } \ 784 } while (0) 785 /* See comment in servconf.h */ 786 COPY_MATCH_STRING_OPTS(); 787 #undef M_CP_STROPT 788 #undef M_CP_STRARRAYOPT 789 790 /* Create valid auth method lists */ 791 if (auth2_setup_methods_lists(authctxt) != 0) { 792 /* 793 * The monitor will continue long enough to let the child 794 * run to it's packet_disconnect(), but it must not allow any 795 * authentication to succeed. 796 */ 797 debug("%s: no valid authentication method lists", __func__); 798 } 799 800 debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed); 801 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 802 803 /* Allow service/style information on the auth context */ 804 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 805 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 806 807 #ifdef USE_PAM 808 if (options.use_pam) 809 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); 810 #endif 811 812 return (0); 813 } 814 815 int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m) 816 { 817 char *banner; 818 int r; 819 820 sshbuf_reset(m); 821 banner = auth2_read_banner(); 822 if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0) 823 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 824 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 825 free(banner); 826 827 return (0); 828 } 829 830 int 831 mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m) 832 { 833 int r; 834 835 monitor_permit_authentications(1); 836 837 if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 || 838 (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0) 839 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 840 debug3("%s: service=%s, style=%s", 841 __func__, authctxt->service, authctxt->style); 842 843 if (strlen(authctxt->style) == 0) { 844 free(authctxt->style); 845 authctxt->style = NULL; 846 } 847 848 return (0); 849 } 850 851 /* 852 * Check that the key type appears in the supplied pattern list, ignoring 853 * mismatches in the signature algorithm. (Signature algorithm checks are 854 * performed in the unprivileged authentication code). 855 * Returns 1 on success, 0 otherwise. 856 */ 857 static int 858 key_base_type_match(const char *method, const struct sshkey *key, 859 const char *list) 860 { 861 char *s, *l, *ol = xstrdup(list); 862 int found = 0; 863 864 l = ol; 865 for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) { 866 if (sshkey_type_from_name(s) == key->type) { 867 found = 1; 868 break; 869 } 870 } 871 if (!found) { 872 error("%s key type %s is not in permitted list %s", method, 873 sshkey_ssh_name(key), list); 874 } 875 876 free(ol); 877 return found; 878 } 879 880 int 881 mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m) 882 { 883 static int call_count; 884 char *passwd; 885 int r, authenticated; 886 size_t plen; 887 888 if (!options.password_authentication) 889 fatal("%s: password authentication not enabled", __func__); 890 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0) 891 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 892 /* Only authenticate if the context is valid */ 893 authenticated = options.password_authentication && 894 auth_password(ssh, passwd); 895 explicit_bzero(passwd, plen); 896 free(passwd); 897 898 sshbuf_reset(m); 899 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 900 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 901 #ifdef USE_PAM 902 if ((r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0) 903 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 904 #endif 905 906 debug3("%s: sending result %d", __func__, authenticated); 907 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 908 909 call_count++; 910 if (plen == 0 && call_count == 1) 911 auth_method = "none"; 912 else 913 auth_method = "password"; 914 915 /* Causes monitor loop to terminate if authenticated */ 916 return (authenticated); 917 } 918 919 #ifdef BSD_AUTH 920 int 921 mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m) 922 { 923 char *name, *infotxt; 924 u_int numprompts, *echo_on, success; 925 char **prompts; 926 int r; 927 928 if (!options.kbd_interactive_authentication) 929 fatal("%s: kbd-int authentication not enabled", __func__); 930 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 931 &prompts, &echo_on) < 0 ? 0 : 1; 932 933 sshbuf_reset(m); 934 if ((r = sshbuf_put_u32(m, success)) != 0) 935 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 936 if (success) { 937 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0) 938 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 939 } 940 941 debug3("%s: sending challenge success: %u", __func__, success); 942 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 943 944 if (success) { 945 free(name); 946 free(infotxt); 947 free(prompts); 948 free(echo_on); 949 } 950 951 return (0); 952 } 953 954 int 955 mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m) 956 { 957 char *response; 958 int r, authok; 959 960 if (!options.kbd_interactive_authentication) 961 fatal("%s: kbd-int authentication not enabled", __func__); 962 if (authctxt->as == NULL) 963 fatal("%s: no bsd auth session", __func__); 964 965 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 966 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 967 authok = options.challenge_response_authentication && 968 auth_userresponse(authctxt->as, response, 0); 969 authctxt->as = NULL; 970 debug3("%s: <%s> = <%d>", __func__, response, authok); 971 free(response); 972 973 sshbuf_reset(m); 974 if ((r = sshbuf_put_u32(m, authok)) != 0) 975 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 976 977 debug3("%s: sending authenticated: %d", __func__, authok); 978 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 979 980 auth_method = "keyboard-interactive"; 981 auth_submethod = "bsdauth"; 982 983 return (authok != 0); 984 } 985 #endif 986 987 #ifdef USE_PAM 988 int 989 mm_answer_pam_start(struct ssh *ssh, int sock, struct sshbuf *m) 990 { 991 if (!options.use_pam) 992 fatal("UsePAM not set, but ended up in %s anyway", __func__); 993 994 start_pam(ssh); 995 996 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); 997 if (options.kbd_interactive_authentication) 998 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 999 1000 return (0); 1001 } 1002 1003 int 1004 mm_answer_pam_account(struct ssh *ssh, int sock, struct sshbuf *m) 1005 { 1006 u_int ret; 1007 int r; 1008 1009 if (!options.use_pam) 1010 fatal("%s: PAM not enabled", __func__); 1011 1012 ret = do_pam_account(); 1013 1014 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1015 (r = sshbuf_put_stringb(m, loginmsg)) != 0) 1016 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1017 1018 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m); 1019 1020 return (ret); 1021 } 1022 1023 static void *sshpam_ctxt, *sshpam_authok; 1024 extern KbdintDevice sshpam_device; 1025 1026 int 1027 mm_answer_pam_init_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1028 { 1029 u_int ok = 0; 1030 int r; 1031 1032 debug3("%s", __func__); 1033 if (!options.kbd_interactive_authentication) 1034 fatal("%s: kbd-int authentication not enabled", __func__); 1035 if (sshpam_ctxt != NULL) 1036 fatal("%s: already called", __func__); 1037 sshpam_ctxt = (sshpam_device.init_ctx)(authctxt); 1038 sshpam_authok = NULL; 1039 sshbuf_reset(m); 1040 if (sshpam_ctxt != NULL) { 1041 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 1042 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_QUERY, 1); 1043 ok = 1; 1044 } 1045 if ((r = sshbuf_put_u32(m, ok)) != 0) 1046 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1047 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); 1048 return (0); 1049 } 1050 1051 int 1052 mm_answer_pam_query(struct ssh *ssh, int sock, struct sshbuf *m) 1053 { 1054 char *name = NULL, *info = NULL, **prompts = NULL; 1055 u_int i, num = 0, *echo_on = 0; 1056 int r, ret; 1057 1058 debug3("%s", __func__); 1059 sshpam_authok = NULL; 1060 if (sshpam_ctxt == NULL) 1061 fatal("%s: no context", __func__); 1062 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, 1063 &num, &prompts, &echo_on); 1064 if (ret == 0 && num == 0) 1065 sshpam_authok = sshpam_ctxt; 1066 if (num > 1 || name == NULL || info == NULL) 1067 fatal("sshpam_device.query failed"); 1068 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_RESPOND, 1); 1069 sshbuf_reset(m); 1070 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1071 (r = sshbuf_put_cstring(m, name)) != 0 || 1072 (r = sshbuf_put_cstring(m, info)) != 0 || 1073 (r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0 || 1074 (r = sshbuf_put_u32(m, num)) != 0) 1075 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1076 free(name); 1077 free(info); 1078 for (i = 0; i < num; ++i) { 1079 if ((r = sshbuf_put_cstring(m, prompts[i])) != 0 || 1080 (r = sshbuf_put_u32(m, echo_on[i])) != 0) 1081 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1082 free(prompts[i]); 1083 } 1084 free(prompts); 1085 free(echo_on); 1086 auth_method = "keyboard-interactive"; 1087 auth_submethod = "pam"; 1088 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m); 1089 return (0); 1090 } 1091 1092 int 1093 mm_answer_pam_respond(struct ssh *ssh, int sock, struct sshbuf *m) 1094 { 1095 char **resp; 1096 u_int i, num; 1097 int r, ret; 1098 1099 debug3("%s", __func__); 1100 if (sshpam_ctxt == NULL) 1101 fatal("%s: no context", __func__); 1102 sshpam_authok = NULL; 1103 if ((r = sshbuf_get_u32(m, &num)) != 0) 1104 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1105 if (num > 0) { 1106 resp = xcalloc(num, sizeof(char *)); 1107 for (i = 0; i < num; ++i) { 1108 if ((r = sshbuf_get_cstring(m, &(resp[i]), NULL)) != 0) 1109 fatal("%s: buffer error: %s", 1110 __func__, ssh_err(r)); 1111 } 1112 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp); 1113 for (i = 0; i < num; ++i) 1114 free(resp[i]); 1115 free(resp); 1116 } else { 1117 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL); 1118 } 1119 sshbuf_reset(m); 1120 if ((r = sshbuf_put_u32(m, ret)) != 0) 1121 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1122 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m); 1123 auth_method = "keyboard-interactive"; 1124 auth_submethod = "pam"; 1125 if (ret == 0) 1126 sshpam_authok = sshpam_ctxt; 1127 return (0); 1128 } 1129 1130 int 1131 mm_answer_pam_free_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1132 { 1133 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt; 1134 1135 debug3("%s", __func__); 1136 if (sshpam_ctxt == NULL) 1137 fatal("%s: no context", __func__); 1138 (sshpam_device.free_ctx)(sshpam_ctxt); 1139 sshpam_ctxt = sshpam_authok = NULL; 1140 sshbuf_reset(m); 1141 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); 1142 /* Allow another attempt */ 1143 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 1144 auth_method = "keyboard-interactive"; 1145 auth_submethod = "pam"; 1146 return r; 1147 } 1148 #endif 1149 1150 int 1151 mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m) 1152 { 1153 struct sshkey *key = NULL; 1154 char *cuser, *chost; 1155 u_int pubkey_auth_attempt; 1156 enum mm_keytype type = 0; 1157 int r, allowed = 0; 1158 struct sshauthopt *opts = NULL; 1159 1160 debug3("%s entering", __func__); 1161 if ((r = sshbuf_get_u32(m, &type)) != 0 || 1162 (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 || 1163 (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 || 1164 (r = sshkey_froms(m, &key)) != 0 || 1165 (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0) 1166 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1167 1168 debug3("%s: key_from_blob: %p", __func__, key); 1169 1170 if (key != NULL && authctxt->valid) { 1171 /* These should not make it past the privsep child */ 1172 if (sshkey_type_plain(key->type) == KEY_RSA && 1173 (datafellows & SSH_BUG_RSASIGMD5) != 0) 1174 fatal("%s: passed a SSH_BUG_RSASIGMD5 key", __func__); 1175 1176 switch (type) { 1177 case MM_USERKEY: 1178 auth_method = "publickey"; 1179 if (!options.pubkey_authentication) 1180 break; 1181 if (auth2_key_already_used(authctxt, key)) 1182 break; 1183 if (!key_base_type_match(auth_method, key, 1184 options.pubkey_key_types)) 1185 break; 1186 allowed = user_key_allowed(ssh, authctxt->pw, key, 1187 pubkey_auth_attempt, &opts); 1188 break; 1189 case MM_HOSTKEY: 1190 auth_method = "hostbased"; 1191 if (!options.hostbased_authentication) 1192 break; 1193 if (auth2_key_already_used(authctxt, key)) 1194 break; 1195 if (!key_base_type_match(auth_method, key, 1196 options.hostbased_key_types)) 1197 break; 1198 allowed = hostbased_key_allowed(ssh, authctxt->pw, 1199 cuser, chost, key); 1200 auth2_record_info(authctxt, 1201 "client user \"%.100s\", client host \"%.100s\"", 1202 cuser, chost); 1203 break; 1204 default: 1205 fatal("%s: unknown key type %d", __func__, type); 1206 break; 1207 } 1208 } 1209 1210 debug3("%s: %s authentication%s: %s key is %s", __func__, 1211 auth_method, pubkey_auth_attempt ? "" : " test", 1212 (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key), 1213 allowed ? "allowed" : "not allowed"); 1214 1215 auth2_record_key(authctxt, 0, key); 1216 1217 /* clear temporarily storage (used by verify) */ 1218 monitor_reset_key_state(); 1219 1220 if (allowed) { 1221 /* Save temporarily for comparison in verify */ 1222 if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0) 1223 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1224 key_blobtype = type; 1225 key_opts = opts; 1226 hostbased_cuser = cuser; 1227 hostbased_chost = chost; 1228 } else { 1229 /* Log failed attempt */ 1230 auth_log(ssh, 0, 0, auth_method, NULL); 1231 free(cuser); 1232 free(chost); 1233 } 1234 sshkey_free(key); 1235 1236 sshbuf_reset(m); 1237 if ((r = sshbuf_put_u32(m, allowed)) != 0) 1238 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1239 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0) 1240 fatal("%s: sshauthopt_serialise: %s", __func__, ssh_err(r)); 1241 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 1242 1243 if (!allowed) 1244 sshauthopt_free(opts); 1245 1246 return (0); 1247 } 1248 1249 static int 1250 monitor_valid_userblob(u_char *data, u_int datalen) 1251 { 1252 struct sshbuf *b; 1253 const u_char *p; 1254 char *userstyle, *cp; 1255 size_t len; 1256 u_char type; 1257 int r, fail = 0; 1258 1259 if ((b = sshbuf_new()) == NULL) 1260 fatal("%s: sshbuf_new", __func__); 1261 if ((r = sshbuf_put(b, data, datalen)) != 0) 1262 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1263 1264 if (datafellows & SSH_OLD_SESSIONID) { 1265 p = sshbuf_ptr(b); 1266 len = sshbuf_len(b); 1267 if ((session_id2 == NULL) || 1268 (len < session_id2_len) || 1269 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1270 fail++; 1271 if ((r = sshbuf_consume(b, session_id2_len)) != 0) 1272 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1273 } else { 1274 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1275 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1276 if ((session_id2 == NULL) || 1277 (len != session_id2_len) || 1278 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1279 fail++; 1280 } 1281 if ((r = sshbuf_get_u8(b, &type)) != 0) 1282 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1283 if (type != SSH2_MSG_USERAUTH_REQUEST) 1284 fail++; 1285 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1286 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1287 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1288 authctxt->style ? ":" : "", 1289 authctxt->style ? authctxt->style : ""); 1290 if (strcmp(userstyle, cp) != 0) { 1291 logit("wrong user name passed to monitor: " 1292 "expected %s != %.100s", userstyle, cp); 1293 fail++; 1294 } 1295 free(userstyle); 1296 free(cp); 1297 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1298 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1299 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1300 if (strcmp("publickey", cp) != 0) 1301 fail++; 1302 free(cp); 1303 if ((r = sshbuf_get_u8(b, &type)) != 0) 1304 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1305 if (type == 0) 1306 fail++; 1307 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1308 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1309 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1310 if (sshbuf_len(b) != 0) 1311 fail++; 1312 sshbuf_free(b); 1313 return (fail == 0); 1314 } 1315 1316 static int 1317 monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser, 1318 char *chost) 1319 { 1320 struct sshbuf *b; 1321 const u_char *p; 1322 char *cp, *userstyle; 1323 size_t len; 1324 int r, fail = 0; 1325 u_char type; 1326 1327 if ((b = sshbuf_new()) == NULL) 1328 fatal("%s: sshbuf_new", __func__); 1329 if ((r = sshbuf_put(b, data, datalen)) != 0 || 1330 (r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1331 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1332 1333 if ((session_id2 == NULL) || 1334 (len != session_id2_len) || 1335 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1336 fail++; 1337 1338 if ((r = sshbuf_get_u8(b, &type)) != 0) 1339 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1340 if (type != SSH2_MSG_USERAUTH_REQUEST) 1341 fail++; 1342 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1343 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1344 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1345 authctxt->style ? ":" : "", 1346 authctxt->style ? authctxt->style : ""); 1347 if (strcmp(userstyle, cp) != 0) { 1348 logit("wrong user name passed to monitor: " 1349 "expected %s != %.100s", userstyle, cp); 1350 fail++; 1351 } 1352 free(userstyle); 1353 free(cp); 1354 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1355 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1356 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1357 if (strcmp(cp, "hostbased") != 0) 1358 fail++; 1359 free(cp); 1360 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1361 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1362 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1363 1364 /* verify client host, strip trailing dot if necessary */ 1365 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1366 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1367 if (((len = strlen(cp)) > 0) && cp[len - 1] == '.') 1368 cp[len - 1] = '\0'; 1369 if (strcmp(cp, chost) != 0) 1370 fail++; 1371 free(cp); 1372 1373 /* verify client user */ 1374 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1375 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1376 if (strcmp(cp, cuser) != 0) 1377 fail++; 1378 free(cp); 1379 1380 if (sshbuf_len(b) != 0) 1381 fail++; 1382 sshbuf_free(b); 1383 return (fail == 0); 1384 } 1385 1386 int 1387 mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m) 1388 { 1389 struct sshkey *key; 1390 u_char *signature, *data, *blob; 1391 char *sigalg; 1392 size_t signaturelen, datalen, bloblen; 1393 int r, ret, valid_data = 0, encoded_ret; 1394 1395 if ((r = sshbuf_get_string(m, &blob, &bloblen)) != 0 || 1396 (r = sshbuf_get_string(m, &signature, &signaturelen)) != 0 || 1397 (r = sshbuf_get_string(m, &data, &datalen)) != 0 || 1398 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0) 1399 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1400 1401 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1402 !monitor_allowed_key(blob, bloblen)) 1403 fatal("%s: bad key, not previously allowed", __func__); 1404 1405 /* Empty signature algorithm means NULL. */ 1406 if (*sigalg == '\0') { 1407 free(sigalg); 1408 sigalg = NULL; 1409 } 1410 1411 /* XXX use sshkey_froms here; need to change key_blob, etc. */ 1412 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0) 1413 fatal("%s: bad public key blob: %s", __func__, ssh_err(r)); 1414 1415 switch (key_blobtype) { 1416 case MM_USERKEY: 1417 valid_data = monitor_valid_userblob(data, datalen); 1418 auth_method = "publickey"; 1419 break; 1420 case MM_HOSTKEY: 1421 valid_data = monitor_valid_hostbasedblob(data, datalen, 1422 hostbased_cuser, hostbased_chost); 1423 auth_method = "hostbased"; 1424 break; 1425 default: 1426 valid_data = 0; 1427 break; 1428 } 1429 if (!valid_data) 1430 fatal("%s: bad signature data blob", __func__); 1431 1432 ret = sshkey_verify(key, signature, signaturelen, data, datalen, 1433 sigalg, ssh->compat); 1434 debug3("%s: %s %p signature %s", __func__, auth_method, key, 1435 (ret == 0) ? "verified" : "unverified"); 1436 auth2_record_key(authctxt, ret == 0, key); 1437 1438 free(blob); 1439 free(signature); 1440 free(data); 1441 free(sigalg); 1442 1443 if (key_blobtype == MM_USERKEY) 1444 auth_activate_options(ssh, key_opts); 1445 monitor_reset_key_state(); 1446 1447 sshkey_free(key); 1448 sshbuf_reset(m); 1449 1450 /* encode ret != 0 as positive integer, since we're sending u32 */ 1451 encoded_ret = (ret != 0); 1452 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0) 1453 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1454 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1455 1456 return ret == 0; 1457 } 1458 1459 static void 1460 mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw) 1461 { 1462 socklen_t fromlen; 1463 struct sockaddr_storage from; 1464 1465 /* 1466 * Get IP address of client. If the connection is not a socket, let 1467 * the address be 0.0.0.0. 1468 */ 1469 memset(&from, 0, sizeof(from)); 1470 fromlen = sizeof(from); 1471 if (ssh_packet_connection_is_on_socket(ssh)) { 1472 if (getpeername(ssh_packet_get_connection_in(ssh), 1473 (struct sockaddr *)&from, &fromlen) < 0) { 1474 debug("getpeername: %.100s", strerror(errno)); 1475 cleanup_exit(255); 1476 } 1477 } 1478 /* Record that there was a login on that tty from the remote host. */ 1479 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1480 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1481 (struct sockaddr *)&from, fromlen); 1482 } 1483 1484 static void 1485 mm_session_close(Session *s) 1486 { 1487 debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid); 1488 if (s->ttyfd != -1) { 1489 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd); 1490 session_pty_cleanup2(s); 1491 } 1492 session_unused(s->self); 1493 } 1494 1495 int 1496 mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m) 1497 { 1498 extern struct monitor *pmonitor; 1499 Session *s; 1500 int r, res, fd0; 1501 1502 debug3("%s entering", __func__); 1503 1504 sshbuf_reset(m); 1505 s = session_new(); 1506 if (s == NULL) 1507 goto error; 1508 s->authctxt = authctxt; 1509 s->pw = authctxt->pw; 1510 s->pid = pmonitor->m_pid; 1511 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1512 if (res == 0) 1513 goto error; 1514 pty_setowner(authctxt->pw, s->tty); 1515 1516 if ((r = sshbuf_put_u32(m, 1)) != 0 || 1517 (r = sshbuf_put_cstring(m, s->tty)) != 0) 1518 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1519 1520 /* We need to trick ttyslot */ 1521 if (dup2(s->ttyfd, 0) == -1) 1522 fatal("%s: dup2", __func__); 1523 1524 mm_record_login(ssh, s, authctxt->pw); 1525 1526 /* Now we can close the file descriptor again */ 1527 close(0); 1528 1529 /* send messages generated by record_login */ 1530 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0) 1531 fatal("%s: put login message: %s", __func__, ssh_err(r)); 1532 sshbuf_reset(loginmsg); 1533 1534 mm_request_send(sock, MONITOR_ANS_PTY, m); 1535 1536 if (mm_send_fd(sock, s->ptyfd) == -1 || 1537 mm_send_fd(sock, s->ttyfd) == -1) 1538 fatal("%s: send fds failed", __func__); 1539 1540 /* make sure nothing uses fd 0 */ 1541 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0) 1542 fatal("%s: open(/dev/null): %s", __func__, strerror(errno)); 1543 if (fd0 != 0) 1544 error("%s: fd0 %d != 0", __func__, fd0); 1545 1546 /* slave is not needed */ 1547 close(s->ttyfd); 1548 s->ttyfd = s->ptyfd; 1549 /* no need to dup() because nobody closes ptyfd */ 1550 s->ptymaster = s->ptyfd; 1551 1552 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd); 1553 1554 return (0); 1555 1556 error: 1557 if (s != NULL) 1558 mm_session_close(s); 1559 if ((r = sshbuf_put_u32(m, 0)) != 0) 1560 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1561 mm_request_send(sock, MONITOR_ANS_PTY, m); 1562 return (0); 1563 } 1564 1565 int 1566 mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m) 1567 { 1568 Session *s; 1569 char *tty; 1570 int r; 1571 1572 debug3("%s entering", __func__); 1573 1574 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0) 1575 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1576 if ((s = session_by_tty(tty)) != NULL) 1577 mm_session_close(s); 1578 sshbuf_reset(m); 1579 free(tty); 1580 return (0); 1581 } 1582 1583 int 1584 mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req) 1585 { 1586 extern struct monitor *pmonitor; 1587 int res, status; 1588 1589 debug3("%s: tearing down sessions", __func__); 1590 1591 /* The child is terminating */ 1592 session_destroy_all(ssh, &mm_session_close); 1593 1594 #ifdef USE_PAM 1595 if (options.use_pam) 1596 sshpam_cleanup(); 1597 #endif 1598 1599 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1600 if (errno != EINTR) 1601 exit(1); 1602 1603 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1604 1605 /* Terminate process */ 1606 exit(res); 1607 } 1608 1609 #ifdef SSH_AUDIT_EVENTS 1610 /* Report that an audit event occurred */ 1611 int 1612 mm_answer_audit_event(struct ssh *ssh, int socket, struct sshbuf *m) 1613 { 1614 u_int n; 1615 ssh_audit_event_t event; 1616 int r; 1617 1618 debug3("%s entering", __func__); 1619 1620 if ((r = sshbuf_get_u32(m, &n)) != 0) 1621 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1622 event = (ssh_audit_event_t)n; 1623 switch (event) { 1624 case SSH_AUTH_FAIL_PUBKEY: 1625 case SSH_AUTH_FAIL_HOSTBASED: 1626 case SSH_AUTH_FAIL_GSSAPI: 1627 case SSH_LOGIN_EXCEED_MAXTRIES: 1628 case SSH_LOGIN_ROOT_DENIED: 1629 case SSH_CONNECTION_CLOSE: 1630 case SSH_INVALID_USER: 1631 audit_event(ssh, event); 1632 break; 1633 default: 1634 fatal("Audit event type %d not permitted", event); 1635 } 1636 1637 return (0); 1638 } 1639 1640 int 1641 mm_answer_audit_command(struct ssh *ssh, int socket, struct sshbuf *m) 1642 { 1643 char *cmd; 1644 int r; 1645 1646 debug3("%s entering", __func__); 1647 if ((r = sshbuf_get_cstring(m, &cmd, NULL)) != 0) 1648 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1649 /* sanity check command, if so how? */ 1650 audit_run_command(cmd); 1651 free(cmd); 1652 return (0); 1653 } 1654 #endif /* SSH_AUDIT_EVENTS */ 1655 1656 void 1657 monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor) 1658 { 1659 ssh_clear_newkeys(ssh, MODE_IN); 1660 ssh_clear_newkeys(ssh, MODE_OUT); 1661 sshbuf_free(child_state); 1662 child_state = NULL; 1663 } 1664 1665 void 1666 monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor) 1667 { 1668 struct kex *kex; 1669 int r; 1670 1671 debug3("%s: packet_set_state", __func__); 1672 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1673 fatal("%s: packet_set_state: %s", __func__, ssh_err(r)); 1674 sshbuf_free(child_state); 1675 child_state = NULL; 1676 1677 if ((kex = ssh->kex) != NULL) { 1678 /* XXX set callbacks */ 1679 #ifdef WITH_OPENSSL 1680 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server; 1681 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server; 1682 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server; 1683 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server; 1684 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server; 1685 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1686 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1687 # ifdef OPENSSL_HAS_ECC 1688 kex->kex[KEX_ECDH_SHA2] = kex_gen_server; 1689 # endif 1690 #endif /* WITH_OPENSSL */ 1691 kex->kex[KEX_C25519_SHA256] = kex_gen_server; 1692 kex->kex[KEX_KEM_SNTRUP4591761X25519_SHA512] = kex_gen_server; 1693 kex->load_host_public_key=&get_hostkey_public_by_type; 1694 kex->load_host_private_key=&get_hostkey_private_by_type; 1695 kex->host_key_index=&get_hostkey_index; 1696 kex->sign = sshd_hostkey_sign; 1697 } 1698 } 1699 1700 /* This function requries careful sanity checking */ 1701 1702 void 1703 mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor) 1704 { 1705 debug3("%s: Waiting for new keys", __func__); 1706 1707 if ((child_state = sshbuf_new()) == NULL) 1708 fatal("%s: sshbuf_new failed", __func__); 1709 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1710 child_state); 1711 debug3("%s: GOT new keys", __func__); 1712 } 1713 1714 1715 /* XXX */ 1716 1717 #define FD_CLOSEONEXEC(x) do { \ 1718 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1719 fatal("fcntl(%d, F_SETFD)", x); \ 1720 } while (0) 1721 1722 static void 1723 monitor_openfds(struct monitor *mon, int do_logfds) 1724 { 1725 int pair[2]; 1726 #ifdef SO_ZEROIZE 1727 int on = 1; 1728 #endif 1729 1730 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1731 fatal("%s: socketpair: %s", __func__, strerror(errno)); 1732 #ifdef SO_ZEROIZE 1733 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) < 0) 1734 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno)); 1735 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) < 0) 1736 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno)); 1737 #endif 1738 FD_CLOSEONEXEC(pair[0]); 1739 FD_CLOSEONEXEC(pair[1]); 1740 mon->m_recvfd = pair[0]; 1741 mon->m_sendfd = pair[1]; 1742 1743 if (do_logfds) { 1744 if (pipe(pair) == -1) 1745 fatal("%s: pipe: %s", __func__, strerror(errno)); 1746 FD_CLOSEONEXEC(pair[0]); 1747 FD_CLOSEONEXEC(pair[1]); 1748 mon->m_log_recvfd = pair[0]; 1749 mon->m_log_sendfd = pair[1]; 1750 } else 1751 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1752 } 1753 1754 #define MM_MEMSIZE 65536 1755 1756 struct monitor * 1757 monitor_init(void) 1758 { 1759 struct monitor *mon; 1760 1761 mon = xcalloc(1, sizeof(*mon)); 1762 monitor_openfds(mon, 1); 1763 1764 return mon; 1765 } 1766 1767 void 1768 monitor_reinit(struct monitor *mon) 1769 { 1770 monitor_openfds(mon, 0); 1771 } 1772 1773 #ifdef GSSAPI 1774 int 1775 mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1776 { 1777 gss_OID_desc goid; 1778 OM_uint32 major; 1779 size_t len; 1780 u_char *p; 1781 int r; 1782 1783 if (!options.gss_authentication) 1784 fatal("%s: GSSAPI authentication not enabled", __func__); 1785 1786 if ((r = sshbuf_get_string(m, &p, &len)) != 0) 1787 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1788 goid.elements = p; 1789 goid.length = len; 1790 1791 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1792 1793 free(goid.elements); 1794 1795 sshbuf_reset(m); 1796 if ((r = sshbuf_put_u32(m, major)) != 0) 1797 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1798 1799 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1800 1801 /* Now we have a context, enable the step */ 1802 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1803 1804 return (0); 1805 } 1806 1807 int 1808 mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1809 { 1810 gss_buffer_desc in; 1811 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1812 OM_uint32 major, minor; 1813 OM_uint32 flags = 0; /* GSI needs this */ 1814 int r; 1815 1816 if (!options.gss_authentication) 1817 fatal("%s: GSSAPI authentication not enabled", __func__); 1818 1819 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0) 1820 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1821 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1822 free(in.value); 1823 1824 sshbuf_reset(m); 1825 if ((r = sshbuf_put_u32(m, major)) != 0 || 1826 (r = sshbuf_put_string(m, out.value, out.length)) != 0 || 1827 (r = sshbuf_put_u32(m, flags)) != 0) 1828 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1829 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1830 1831 gss_release_buffer(&minor, &out); 1832 1833 if (major == GSS_S_COMPLETE) { 1834 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1835 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1836 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1837 } 1838 return (0); 1839 } 1840 1841 int 1842 mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m) 1843 { 1844 gss_buffer_desc gssbuf, mic; 1845 OM_uint32 ret; 1846 int r; 1847 1848 if (!options.gss_authentication) 1849 fatal("%s: GSSAPI authentication not enabled", __func__); 1850 1851 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 || 1852 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0) 1853 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1854 1855 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1856 1857 free(gssbuf.value); 1858 free(mic.value); 1859 1860 sshbuf_reset(m); 1861 if ((r = sshbuf_put_u32(m, ret)) != 0) 1862 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1863 1864 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1865 1866 if (!GSS_ERROR(ret)) 1867 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1868 1869 return (0); 1870 } 1871 1872 int 1873 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m) 1874 { 1875 int r, authenticated; 1876 const char *displayname; 1877 1878 if (!options.gss_authentication) 1879 fatal("%s: GSSAPI authentication not enabled", __func__); 1880 1881 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1882 1883 sshbuf_reset(m); 1884 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 1885 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1886 1887 debug3("%s: sending result %d", __func__, authenticated); 1888 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1889 1890 auth_method = "gssapi-with-mic"; 1891 1892 if ((displayname = ssh_gssapi_displayname()) != NULL) 1893 auth2_record_info(authctxt, "%s", displayname); 1894 1895 /* Monitor loop will terminate if authenticated */ 1896 return (authenticated); 1897 } 1898 #endif /* GSSAPI */ 1899 1900