1 /* $NetBSD: monitor.c,v 1.44 2024/06/25 16:58:24 christos Exp $ */ 2 /* $OpenBSD: monitor.c,v 1.237 2023/08/16 16:14:11 djm Exp $ */ 3 4 /* 5 * Copyright 2002 Niels Provos <provos@citi.umich.edu> 6 * Copyright 2002 Markus Friedl <markus@openbsd.org> 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30 #include "includes.h" 31 __RCSID("$NetBSD: monitor.c,v 1.44 2024/06/25 16:58:24 christos Exp $"); 32 #include <sys/types.h> 33 #include <sys/wait.h> 34 #include <sys/socket.h> 35 #include <sys/tree.h> 36 #include <sys/queue.h> 37 38 #ifdef WITH_OPENSSL 39 #include <openssl/dh.h> 40 #endif 41 42 #include <errno.h> 43 #include <fcntl.h> 44 #include <limits.h> 45 #include <paths.h> 46 #include <poll.h> 47 #include <pwd.h> 48 #include <signal.h> 49 #include <stdarg.h> 50 #include <unistd.h> 51 #include <stdint.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <unistd.h> 56 57 #include "atomicio.h" 58 #include "xmalloc.h" 59 #include "ssh.h" 60 #include "sshkey.h" 61 #include "sshbuf.h" 62 #include "hostfile.h" 63 #include "auth.h" 64 #include "cipher.h" 65 #include "kex.h" 66 #include "dh.h" 67 #include "packet.h" 68 #include "auth-options.h" 69 #include "sshpty.h" 70 #include "channels.h" 71 #include "session.h" 72 #include "sshlogin.h" 73 #include "canohost.h" 74 #include "log.h" 75 #include "misc.h" 76 #include "servconf.h" 77 #include "monitor.h" 78 #ifdef GSSAPI 79 #include "ssh-gss.h" 80 #endif 81 #include "monitor_wrap.h" 82 #include "monitor_fdpass.h" 83 #include "compat.h" 84 #include "ssh2.h" 85 #include "authfd.h" 86 #include "match.h" 87 #include "ssherr.h" 88 #include "sk-api.h" 89 90 #include "pfilter.h" 91 92 #ifdef GSSAPI 93 static Gssctxt *gsscontext = NULL; 94 #endif 95 96 /* Imports */ 97 extern ServerOptions options; 98 extern u_int utmp_len; 99 extern struct sshbuf *loginmsg; 100 extern struct sshauthopt *auth_opts; /* XXX move to permanent ssh->authctxt? */ 101 102 /* State exported from the child */ 103 static struct sshbuf *child_state; 104 105 /* Functions on the monitor that answer unprivileged requests */ 106 107 int mm_answer_moduli(struct ssh *, int, struct sshbuf *); 108 int mm_answer_sign(struct ssh *, int, struct sshbuf *); 109 int mm_answer_pwnamallow(struct ssh *, int, struct sshbuf *); 110 int mm_answer_auth2_read_banner(struct ssh *, int, struct sshbuf *); 111 int mm_answer_authserv(struct ssh *, int, struct sshbuf *); 112 int mm_answer_authpassword(struct ssh *, int, struct sshbuf *); 113 int mm_answer_bsdauthquery(struct ssh *, int, struct sshbuf *); 114 int mm_answer_bsdauthrespond(struct ssh *, int, struct sshbuf *); 115 int mm_answer_keyallowed(struct ssh *, int, struct sshbuf *); 116 int mm_answer_keyverify(struct ssh *, int, struct sshbuf *); 117 int mm_answer_pty(struct ssh *, int, struct sshbuf *); 118 int mm_answer_pty_cleanup(struct ssh *, int, struct sshbuf *); 119 int mm_answer_term(struct ssh *, int, struct sshbuf *); 120 int mm_answer_sesskey(struct ssh *, int, struct sshbuf *); 121 int mm_answer_sessid(struct ssh *, int, struct sshbuf *); 122 123 #ifdef USE_PAM 124 int mm_answer_pam_start(struct ssh *, int, struct sshbuf *); 125 int mm_answer_pam_account(struct ssh *, int, struct sshbuf *); 126 int mm_answer_pam_init_ctx(struct ssh *, int, struct sshbuf *); 127 int mm_answer_pam_query(struct ssh *, int, struct sshbuf *); 128 int mm_answer_pam_respond(struct ssh *, int, struct sshbuf *); 129 int mm_answer_pam_free_ctx(struct ssh *, int, struct sshbuf *); 130 #endif 131 132 #ifdef KRB5 133 int mm_answer_krb5(struct ssh *, int, struct sshbuf *); 134 #endif 135 136 #ifdef GSSAPI 137 int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *); 138 int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *); 139 int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *); 140 int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *); 141 #endif 142 143 /* local state for key verify */ 144 static u_char *key_blob = NULL; 145 static size_t key_bloblen = 0; 146 static u_int key_blobtype = MM_NOKEY; 147 static struct sshauthopt *key_opts = NULL; 148 static char *hostbased_cuser = NULL; 149 static char *hostbased_chost = NULL; 150 static const char *auth_method = "unknown"; 151 static const char *auth_submethod = NULL; 152 static u_int session_id2_len = 0; 153 static u_char *session_id2 = NULL; 154 static pid_t monitor_child_pid; 155 156 struct mon_table { 157 enum monitor_reqtype type; 158 int flags; 159 int (*f)(struct ssh *, int, struct sshbuf *); 160 }; 161 162 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 163 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 164 #define MON_ONCE 0x0010 /* Disable after calling */ 165 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 166 167 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 168 169 #define MON_PERMIT 0x1000 /* Request is permitted */ 170 171 static int monitor_read(struct ssh *, struct monitor *, struct mon_table *, 172 struct mon_table **); 173 static int monitor_read_log(struct monitor *); 174 175 struct mon_table mon_dispatch_proto20[] = { 176 #ifdef WITH_OPENSSL 177 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 178 #endif 179 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 180 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 181 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 182 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 183 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 184 #ifdef USE_PAM 185 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 186 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 187 {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx}, 188 {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query}, 189 {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond}, 190 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 191 #endif 192 #ifdef BSD_AUTH 193 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 194 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 195 #endif 196 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 197 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 198 #ifdef KRB5 199 {MONITOR_REQ_KRB5, MON_ONCE|MON_AUTH, mm_answer_krb5}, 200 #endif 201 #ifdef GSSAPI 202 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 203 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx}, 204 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok}, 205 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic}, 206 #endif 207 {0, 0, NULL} 208 }; 209 210 struct mon_table mon_dispatch_postauth20[] = { 211 #ifdef WITH_OPENSSL 212 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 213 #endif 214 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 215 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 216 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 217 {MONITOR_REQ_TERM, 0, mm_answer_term}, 218 {0, 0, NULL} 219 }; 220 221 struct mon_table *mon_dispatch; 222 223 /* Specifies if a certain message is allowed at the moment */ 224 static void 225 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 226 { 227 while (ent->f != NULL) { 228 if (ent->type == type) { 229 ent->flags &= ~MON_PERMIT; 230 ent->flags |= permit ? MON_PERMIT : 0; 231 return; 232 } 233 ent++; 234 } 235 } 236 237 static void 238 monitor_permit_authentications(int permit) 239 { 240 struct mon_table *ent = mon_dispatch; 241 242 while (ent->f != NULL) { 243 if (ent->flags & MON_AUTH) { 244 ent->flags &= ~MON_PERMIT; 245 ent->flags |= permit ? MON_PERMIT : 0; 246 } 247 ent++; 248 } 249 } 250 251 void 252 monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor) 253 { 254 struct mon_table *ent; 255 int authenticated = 0, partial = 0; 256 Authctxt *authctxt = ssh->authctxt; 257 258 debug3("preauth child monitor started"); 259 260 if (pmonitor->m_recvfd >= 0) 261 close(pmonitor->m_recvfd); 262 if (pmonitor->m_log_sendfd >= 0) 263 close(pmonitor->m_log_sendfd); 264 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 265 266 memset(authctxt, 0, sizeof(*authctxt)); 267 ssh->authctxt = authctxt; 268 269 mon_dispatch = mon_dispatch_proto20; 270 /* Permit requests for moduli and signatures */ 271 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 272 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 273 274 /* The first few requests do not require asynchronous access */ 275 while (!authenticated) { 276 partial = 0; 277 auth_method = "unknown"; 278 auth_submethod = NULL; 279 auth2_authctxt_reset_info(authctxt); 280 281 authenticated = (monitor_read(ssh, pmonitor, 282 mon_dispatch, &ent) == 1); 283 284 /* Special handling for multiple required authentications */ 285 if (options.num_auth_methods != 0) { 286 if (authenticated && 287 !auth2_update_methods_lists(authctxt, 288 auth_method, auth_submethod)) { 289 debug3_f("method %s: partial", auth_method); 290 authenticated = 0; 291 partial = 1; 292 } 293 } 294 295 if (authenticated) { 296 if (!(ent->flags & MON_AUTHDECIDE)) 297 fatal_f("unexpected authentication from %d", 298 ent->type); 299 if (authctxt->pw->pw_uid == 0 && 300 !auth_root_allowed(ssh, auth_method)) 301 authenticated = 0; 302 #ifdef USE_PAM 303 /* PAM needs to perform account checks after auth */ 304 if (options.use_pam && authenticated) { 305 struct sshbuf *m; 306 307 if ((m = sshbuf_new()) == NULL) 308 fatal("%s: sshbuf_new failed", __func__); 309 310 mm_request_receive_expect(pmonitor->m_sendfd, 311 MONITOR_REQ_PAM_ACCOUNT, m); 312 authenticated = mm_answer_pam_account(ssh, pmonitor->m_sendfd, m); 313 sshbuf_free(m); 314 } 315 #endif 316 } 317 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 318 auth_log(ssh, authenticated, partial, 319 auth_method, auth_submethod); 320 if (!partial && !authenticated) { 321 authctxt->failures++; 322 } 323 if (authenticated || partial) { 324 auth2_update_session_info(authctxt, 325 auth_method, auth_submethod); 326 } 327 } 328 if (authctxt->failures > options.max_authtries) { 329 pfilter_notify(1); 330 /* Shouldn't happen */ 331 fatal_f("privsep child made too many authentication " 332 "attempts"); 333 } 334 } 335 336 if (!authctxt->valid) { 337 pfilter_notify(1); 338 fatal_f("authenticated invalid user"); 339 } 340 if (strcmp(auth_method, "unknown") == 0) { 341 pfilter_notify(1); 342 fatal_f("authentication method name unknown"); 343 } 344 345 debug_f("user %s authenticated by privileged process", authctxt->user); 346 ssh->authctxt = NULL; 347 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 348 349 mm_get_keystate(ssh, pmonitor); 350 351 /* Drain any buffered messages from the child */ 352 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 353 ; 354 355 if (pmonitor->m_recvfd >= 0) 356 close(pmonitor->m_recvfd); 357 if (pmonitor->m_log_sendfd >= 0) 358 close(pmonitor->m_log_sendfd); 359 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 360 } 361 362 static void 363 monitor_set_child_handler(pid_t pid) 364 { 365 monitor_child_pid = pid; 366 } 367 368 static void 369 monitor_child_handler(int sig) 370 { 371 kill(monitor_child_pid, sig); 372 } 373 374 void 375 monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor) 376 { 377 close(pmonitor->m_recvfd); 378 pmonitor->m_recvfd = -1; 379 380 monitor_set_child_handler(pmonitor->m_pid); 381 ssh_signal(SIGHUP, &monitor_child_handler); 382 ssh_signal(SIGTERM, &monitor_child_handler); 383 ssh_signal(SIGINT, &monitor_child_handler); 384 385 mon_dispatch = mon_dispatch_postauth20; 386 387 /* Permit requests for moduli and signatures */ 388 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 389 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 390 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 391 392 if (auth_opts->permit_pty_flag) { 393 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 394 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 395 } 396 397 for (;;) 398 monitor_read(ssh, pmonitor, mon_dispatch, NULL); 399 } 400 401 static int 402 monitor_read_log(struct monitor *pmonitor) 403 { 404 struct sshbuf *logmsg; 405 u_int len, level, forced; 406 char *msg; 407 u_char *p; 408 int r; 409 410 if ((logmsg = sshbuf_new()) == NULL) 411 fatal_f("sshbuf_new"); 412 413 /* Read length */ 414 if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0) 415 fatal_fr(r, "reserve len"); 416 if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) { 417 if (errno == EPIPE) { 418 sshbuf_free(logmsg); 419 debug_f("child log fd closed"); 420 close(pmonitor->m_log_recvfd); 421 pmonitor->m_log_recvfd = -1; 422 return -1; 423 } 424 fatal_f("log fd read: %s", strerror(errno)); 425 } 426 if ((r = sshbuf_get_u32(logmsg, &len)) != 0) 427 fatal_fr(r, "parse len"); 428 if (len <= 4 || len > 8192) 429 fatal_f("invalid log message length %u", len); 430 431 /* Read severity, message */ 432 sshbuf_reset(logmsg); 433 if ((r = sshbuf_reserve(logmsg, len, &p)) != 0) 434 fatal_fr(r, "reserve msg"); 435 if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len) 436 fatal_f("log fd read: %s", strerror(errno)); 437 if ((r = sshbuf_get_u32(logmsg, &level)) != 0 || 438 (r = sshbuf_get_u32(logmsg, &forced)) != 0 || 439 (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0) 440 fatal_fr(r, "parse"); 441 442 /* Log it */ 443 if (log_level_name(level) == NULL) 444 fatal_f("invalid log level %u (corrupted message?)", level); 445 sshlogdirect(level, forced, "%s [preauth]", msg); 446 447 sshbuf_free(logmsg); 448 free(msg); 449 450 return 0; 451 } 452 453 static int 454 monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent, 455 struct mon_table **pent) 456 { 457 struct sshbuf *m; 458 int r, ret; 459 u_char type; 460 struct pollfd pfd[2]; 461 462 for (;;) { 463 memset(&pfd, 0, sizeof(pfd)); 464 pfd[0].fd = pmonitor->m_sendfd; 465 pfd[0].events = POLLIN; 466 pfd[1].fd = pmonitor->m_log_recvfd; 467 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 468 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 469 if (errno == EINTR || errno == EAGAIN) 470 continue; 471 fatal_f("poll: %s", strerror(errno)); 472 } 473 if (pfd[1].revents) { 474 /* 475 * Drain all log messages before processing next 476 * monitor request. 477 */ 478 monitor_read_log(pmonitor); 479 continue; 480 } 481 if (pfd[0].revents) 482 break; /* Continues below */ 483 } 484 485 if ((m = sshbuf_new()) == NULL) 486 fatal_f("sshbuf_new"); 487 488 mm_request_receive(pmonitor->m_sendfd, m); 489 if ((r = sshbuf_get_u8(m, &type)) != 0) 490 fatal_fr(r, "parse type"); 491 492 debug3_f("checking request %d", type); 493 494 while (ent->f != NULL) { 495 if (ent->type == type) 496 break; 497 ent++; 498 } 499 500 if (ent->f != NULL) { 501 if (!(ent->flags & MON_PERMIT)) 502 fatal_f("unpermitted request %d", type); 503 ret = (*ent->f)(ssh, pmonitor->m_sendfd, m); 504 sshbuf_free(m); 505 506 /* The child may use this request only once, disable it */ 507 if (ent->flags & MON_ONCE) { 508 debug2_f("%d used once, disabling now", type); 509 ent->flags &= ~MON_PERMIT; 510 } 511 512 if (pent != NULL) 513 *pent = ent; 514 515 return ret; 516 } 517 518 fatal_f("unsupported request: %d", type); 519 520 /* NOTREACHED */ 521 return (-1); 522 } 523 524 /* allowed key state */ 525 static int 526 monitor_allowed_key(const u_char *blob, u_int bloblen) 527 { 528 /* make sure key is allowed */ 529 if (key_blob == NULL || key_bloblen != bloblen || 530 timingsafe_bcmp(key_blob, blob, key_bloblen)) 531 return (0); 532 return (1); 533 } 534 535 static void 536 monitor_reset_key_state(void) 537 { 538 /* reset state */ 539 free(key_blob); 540 free(hostbased_cuser); 541 free(hostbased_chost); 542 sshauthopt_free(key_opts); 543 key_blob = NULL; 544 key_bloblen = 0; 545 key_blobtype = MM_NOKEY; 546 key_opts = NULL; 547 hostbased_cuser = NULL; 548 hostbased_chost = NULL; 549 } 550 551 #ifdef WITH_OPENSSL 552 int 553 mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m) 554 { 555 DH *dh; 556 const BIGNUM *dh_p, *dh_g; 557 int r; 558 u_int min, want, max; 559 560 if ((r = sshbuf_get_u32(m, &min)) != 0 || 561 (r = sshbuf_get_u32(m, &want)) != 0 || 562 (r = sshbuf_get_u32(m, &max)) != 0) 563 fatal_fr(r, "parse"); 564 565 debug3_f("got parameters: %d %d %d", min, want, max); 566 /* We need to check here, too, in case the child got corrupted */ 567 if (max < min || want < min || max < want) 568 fatal_f("bad parameters: %d %d %d", min, want, max); 569 570 sshbuf_reset(m); 571 572 dh = choose_dh(min, want, max); 573 if (dh == NULL) { 574 if ((r = sshbuf_put_u8(m, 0)) != 0) 575 fatal_fr(r, "assemble empty"); 576 return (0); 577 } else { 578 /* Send first bignum */ 579 DH_get0_pqg(dh, &dh_p, NULL, &dh_g); 580 if ((r = sshbuf_put_u8(m, 1)) != 0 || 581 (r = sshbuf_put_bignum2(m, dh_p)) != 0 || 582 (r = sshbuf_put_bignum2(m, dh_g)) != 0) 583 fatal_fr(r, "assemble"); 584 585 DH_free(dh); 586 } 587 mm_request_send(sock, MONITOR_ANS_MODULI, m); 588 return (0); 589 } 590 #endif 591 592 int 593 mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m) 594 { 595 extern int auth_sock; /* XXX move to state struct? */ 596 struct sshkey *key; 597 struct sshbuf *sigbuf = NULL; 598 u_char *p = NULL, *signature = NULL; 599 char *alg = NULL; 600 size_t datlen, siglen, alglen; 601 int r, is_proof = 0; 602 u_int keyid, compat; 603 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 604 605 debug3_f("entering"); 606 607 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 608 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 609 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0 || 610 (r = sshbuf_get_u32(m, &compat)) != 0) 611 fatal_fr(r, "parse"); 612 if (keyid > INT_MAX) 613 fatal_f("invalid key ID"); 614 615 /* 616 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 617 * SHA384 (48 bytes) and SHA512 (64 bytes). 618 * 619 * Otherwise, verify the signature request is for a hostkey 620 * proof. 621 * 622 * XXX perform similar check for KEX signature requests too? 623 * it's not trivial, since what is signed is the hash, rather 624 * than the full kex structure... 625 */ 626 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 627 /* 628 * Construct expected hostkey proof and compare it to what 629 * the client sent us. 630 */ 631 if (session_id2_len == 0) /* hostkeys is never first */ 632 fatal_f("bad data length: %zu", datlen); 633 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 634 fatal_f("no hostkey for index %d", keyid); 635 if ((sigbuf = sshbuf_new()) == NULL) 636 fatal_f("sshbuf_new"); 637 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 638 (r = sshbuf_put_string(sigbuf, session_id2, 639 session_id2_len)) != 0 || 640 (r = sshkey_puts(key, sigbuf)) != 0) 641 fatal_fr(r, "assemble private key proof"); 642 if (datlen != sshbuf_len(sigbuf) || 643 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 644 fatal_f("bad data length: %zu, hostkey proof len %zu", 645 datlen, sshbuf_len(sigbuf)); 646 sshbuf_free(sigbuf); 647 is_proof = 1; 648 } 649 650 /* save session id, it will be passed on the first call */ 651 if (session_id2_len == 0) { 652 session_id2_len = datlen; 653 session_id2 = xmalloc(session_id2_len); 654 memcpy(session_id2, p, session_id2_len); 655 } 656 657 if ((key = get_hostkey_by_index(keyid)) != NULL) { 658 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 659 options.sk_provider, NULL, compat)) != 0) 660 fatal_fr(r, "sign"); 661 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 662 auth_sock > 0) { 663 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 664 p, datlen, alg, compat)) != 0) 665 fatal_fr(r, "agent sign"); 666 } else 667 fatal_f("no hostkey from index %d", keyid); 668 669 debug3_f("%s %s signature len=%zu", alg, 670 is_proof ? "hostkey proof" : "KEX", siglen); 671 672 sshbuf_reset(m); 673 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 674 fatal_fr(r, "assemble"); 675 676 free(alg); 677 free(p); 678 free(signature); 679 680 mm_request_send(sock, MONITOR_ANS_SIGN, m); 681 682 /* Turn on permissions for getpwnam */ 683 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 684 685 return (0); 686 } 687 688 #define PUTPW(b, id) \ 689 do { \ 690 if ((r = sshbuf_put_string(b, \ 691 &pwent->id, sizeof(pwent->id))) != 0) \ 692 fatal_fr(r, "assemble %s", #id); \ 693 } while (0) 694 695 /* Retrieves the password entry and also checks if the user is permitted */ 696 int 697 mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m) 698 { 699 struct passwd *pwent; 700 int r, allowed = 0; 701 u_int i; 702 Authctxt *authctxt = ssh->authctxt; 703 704 debug3_f("entering"); 705 706 if (authctxt->attempt++ != 0) 707 fatal_f("multiple attempts for getpwnam"); 708 709 if ((r = sshbuf_get_cstring(m, &authctxt->user, NULL)) != 0) 710 fatal_fr(r, "parse"); 711 712 pwent = getpwnamallow(ssh, authctxt->user); 713 714 setproctitle("%s [priv]", pwent ? authctxt->user : "unknown"); 715 716 sshbuf_reset(m); 717 718 if (pwent == NULL) { 719 if ((r = sshbuf_put_u8(m, 0)) != 0) 720 fatal_fr(r, "assemble fakepw"); 721 authctxt->pw = fakepw(); 722 goto out; 723 } 724 725 allowed = 1; 726 authctxt->pw = pwent; 727 authctxt->valid = 1; 728 729 /* XXX send fake class/dir/shell, etc. */ 730 if ((r = sshbuf_put_u8(m, 1)) != 0) 731 fatal_fr(r, "assemble ok"); 732 PUTPW(m, pw_uid); 733 PUTPW(m, pw_gid); 734 PUTPW(m, pw_change); 735 PUTPW(m, pw_expire); 736 if ((r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || 737 (r = sshbuf_put_cstring(m, "*")) != 0 || 738 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 || 739 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 || 740 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 || 741 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0) 742 fatal_fr(r, "assemble pw"); 743 744 out: 745 ssh_packet_set_log_preamble(ssh, "%suser %s", 746 authctxt->valid ? "authenticating" : "invalid ", authctxt->user); 747 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0) 748 fatal_fr(r, "assemble options"); 749 750 #define M_CP_STROPT(x) do { \ 751 if (options.x != NULL && \ 752 (r = sshbuf_put_cstring(m, options.x)) != 0) \ 753 fatal_fr(r, "assemble %s", #x); \ 754 } while (0) 755 #define M_CP_STRARRAYOPT(x, nx) do { \ 756 for (i = 0; i < options.nx; i++) { \ 757 if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \ 758 fatal_fr(r, "assemble %s", #x); \ 759 } \ 760 } while (0) 761 /* See comment in servconf.h */ 762 COPY_MATCH_STRING_OPTS(); 763 #undef M_CP_STROPT 764 #undef M_CP_STRARRAYOPT 765 766 /* Create valid auth method lists */ 767 if (auth2_setup_methods_lists(authctxt) != 0) { 768 /* 769 * The monitor will continue long enough to let the child 770 * run to its packet_disconnect(), but it must not allow any 771 * authentication to succeed. 772 */ 773 debug_f("no valid authentication method lists"); 774 } 775 776 debug3_f("sending MONITOR_ANS_PWNAM: %d", allowed); 777 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 778 779 /* Allow service/style information on the auth context */ 780 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 781 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 782 783 #ifdef USE_PAM 784 if (options.use_pam) 785 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); 786 #endif 787 788 return (0); 789 } 790 791 int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m) 792 { 793 char *banner; 794 int r; 795 796 sshbuf_reset(m); 797 banner = auth2_read_banner(); 798 if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0) 799 fatal_fr(r, "assemble"); 800 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 801 free(banner); 802 803 return (0); 804 } 805 806 int 807 mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m) 808 { 809 int r; 810 Authctxt *authctxt = ssh->authctxt; 811 812 monitor_permit_authentications(1); 813 814 if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 || 815 (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0) 816 fatal_fr(r, "parse"); 817 debug3_f("service=%s, style=%s", authctxt->service, authctxt->style); 818 819 if (strlen(authctxt->style) == 0) { 820 free(authctxt->style); 821 authctxt->style = NULL; 822 } 823 824 return (0); 825 } 826 827 int 828 mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m) 829 { 830 static int call_count; 831 char *passwd; 832 int r, authenticated; 833 size_t plen; 834 835 if (!options.password_authentication) 836 fatal_f("password authentication not enabled"); 837 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0) 838 fatal_fr(r, "parse"); 839 /* Only authenticate if the context is valid */ 840 authenticated = options.password_authentication && 841 auth_password(ssh, passwd); 842 freezero(passwd, plen); 843 844 sshbuf_reset(m); 845 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 846 fatal_fr(r, "assemble"); 847 848 debug3_f("sending result %d", authenticated); 849 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 850 851 call_count++; 852 if (plen == 0 && call_count == 1) 853 auth_method = "none"; 854 else 855 auth_method = "password"; 856 857 /* Causes monitor loop to terminate if authenticated */ 858 return (authenticated); 859 } 860 861 #ifdef BSD_AUTH 862 int 863 mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m) 864 { 865 char *name, *infotxt; 866 u_int numprompts, *echo_on, success; 867 char **prompts; 868 int r; 869 870 if (!options.kbd_interactive_authentication) 871 fatal_f("kbd-int authentication not enabled"); 872 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 873 &prompts, &echo_on) < 0 ? 0 : 1; 874 875 sshbuf_reset(m); 876 if ((r = sshbuf_put_u32(m, success)) != 0) 877 fatal_fr(r, "assemble"); 878 if (success) { 879 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0) 880 fatal_fr(r, "assemble prompt"); 881 } 882 883 debug3_f("sending challenge success: %u", success); 884 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 885 886 if (success) { 887 free(name); 888 free(infotxt); 889 free(prompts); 890 free(echo_on); 891 } 892 893 return (0); 894 } 895 896 int 897 mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m) 898 { 899 char *response; 900 int r, authok; 901 902 if (!options.kbd_interactive_authentication) 903 fatal_f("kbd-int authentication not enabled"); 904 if (authctxt->as == NULL) 905 fatal_f("no bsd auth session"); 906 907 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 908 fatal_fr(r, "parse"); 909 authok = options.kbd_interactive_authentication && 910 auth_userresponse(authctxt->as, response, 0); 911 authctxt->as = NULL; 912 debug3_f("<%s> = <%d>", response, authok); 913 free(response); 914 915 sshbuf_reset(m); 916 if ((r = sshbuf_put_u32(m, authok)) != 0) 917 fatal_fr(r, "assemble"); 918 919 debug3_f("sending authenticated: %d", authok); 920 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 921 922 auth_method = "keyboard-interactive"; 923 auth_submethod = "bsdauth"; 924 925 return (authok != 0); 926 } 927 #endif 928 929 #ifdef SKEY 930 int 931 mm_answer_skeyquery(int sock, struct sshbuf *m) 932 { 933 struct skey skey; 934 char challenge[1024]; 935 u_int success; 936 937 success = skeychallenge(&skey, authctxt->user, challenge, 938 sizeof(challenge)) < 0 ? 0 : 1; 939 940 sshbuf_reset(m); 941 sshbuf_put_int(m, success); 942 if (success) 943 sshbuf_put_cstring(m, challenge); 944 945 debug3("%s: sending challenge success: %u", __func__, success); 946 mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m); 947 948 return (0); 949 } 950 951 int 952 mm_answer_skeyrespond(int sock, struct sshbuf *m) 953 { 954 char *response; 955 int authok; 956 int r; 957 958 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 959 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 960 961 authok = (options.kbd_interactive_authentication && 962 authctxt->valid && 963 skey_haskey(authctxt->pw->pw_name) == 0 && 964 skey_passcheck(authctxt->pw->pw_name, response) != -1); 965 966 free(response); 967 968 sshbuf_reset(m); 969 sshbuf_put_int(m, authok); 970 971 debug3("%s: sending authenticated: %d", __func__, authok); 972 mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m); 973 974 auth_method = "skey"; 975 auth_submethod = "bsdauth"; 976 977 return (authok != 0); 978 } 979 #endif 980 981 #ifdef USE_PAM 982 int 983 mm_answer_pam_start(struct ssh *ssh, int sock, struct sshbuf *m) 984 { 985 if (!options.use_pam) 986 fatal("UsePAM not set, but ended up in %s anyway", __func__); 987 988 start_pam(ssh); 989 990 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); 991 992 return (0); 993 } 994 995 int 996 mm_answer_pam_account(struct ssh *ssh, int sock, struct sshbuf *m) 997 { 998 u_int ret; 999 1000 if (!options.use_pam) 1001 fatal("UsePAM not set, but ended up in %s anyway", __func__); 1002 1003 ret = do_pam_account(); 1004 1005 sshbuf_put_u32(m, ret); 1006 sshbuf_put_string(m, sshbuf_ptr(loginmsg), sshbuf_len(loginmsg)); 1007 1008 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m); 1009 1010 return (ret); 1011 } 1012 1013 static void *sshpam_ctxt, *sshpam_authok; 1014 extern KbdintDevice sshpam_device; 1015 1016 int 1017 mm_answer_pam_init_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1018 { 1019 debug3("%s", __func__); 1020 sshpam_ctxt = (sshpam_device.init_ctx)(ssh->authctxt); 1021 sshpam_authok = NULL; 1022 sshbuf_reset(m); 1023 if (sshpam_ctxt != NULL) { 1024 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 1025 sshbuf_put_u32(m, 1); 1026 } else { 1027 sshbuf_put_u32(m, 0); 1028 } 1029 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); 1030 return (0); 1031 } 1032 1033 int 1034 mm_answer_pam_query(struct ssh *ssh, int sock, struct sshbuf *m) 1035 { 1036 char *name, *info, **prompts; 1037 u_int i, num, *echo_on; 1038 int ret; 1039 1040 debug3("%s", __func__); 1041 sshpam_authok = NULL; 1042 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, &num, &prompts, &echo_on); 1043 if (ret == 0 && num == 0) 1044 sshpam_authok = sshpam_ctxt; 1045 if (num > 1 || name == NULL || info == NULL) 1046 ret = -1; 1047 sshbuf_reset(m); 1048 sshbuf_put_u32(m, ret); 1049 sshbuf_put_cstring(m, name); 1050 free(name); 1051 sshbuf_put_cstring(m, info); 1052 free(info); 1053 sshbuf_put_u32(m, num); 1054 for (i = 0; i < num; ++i) { 1055 sshbuf_put_cstring(m, prompts[i]); 1056 free(prompts[i]); 1057 sshbuf_put_u32(m, echo_on[i]); 1058 } 1059 if (prompts != NULL) 1060 free(prompts); 1061 if (echo_on != NULL) 1062 free(echo_on); 1063 auth_method = "keyboard-interactive/pam"; 1064 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m); 1065 return (0); 1066 } 1067 1068 int 1069 mm_answer_pam_respond(struct ssh *ssh, int sock, struct sshbuf *m) 1070 { 1071 char **resp; 1072 u_int i, num; 1073 int ret, r; 1074 1075 debug3("%s", __func__); 1076 sshpam_authok = NULL; 1077 if ((r = sshbuf_get_u32(m, &num)) != 0) 1078 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1079 if (num > 0) { 1080 resp = xmalloc(num * sizeof(char *)); 1081 for (i = 0; i < num; ++i) 1082 if ((r = sshbuf_get_cstring(m, &resp[i], NULL)) != 0) 1083 fatal("%s: buffer error: %s", __func__, 1084 ssh_err(r)); 1085 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp); 1086 for (i = 0; i < num; ++i) 1087 free(resp[i]); 1088 free(resp); 1089 } else { 1090 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL); 1091 } 1092 sshbuf_reset(m); 1093 sshbuf_put_u32(m, ret); 1094 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m); 1095 auth_method = "keyboard-interactive/pam"; 1096 if (ret == 0) 1097 sshpam_authok = sshpam_ctxt; 1098 return (0); 1099 } 1100 1101 int 1102 mm_answer_pam_free_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1103 { 1104 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt; 1105 1106 debug3("%s", __func__); 1107 (sshpam_device.free_ctx)(sshpam_ctxt); 1108 sshpam_ctxt = sshpam_authok = NULL; 1109 sshbuf_reset(m); 1110 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); 1111 auth_method = "keyboard-interactive/pam"; 1112 return r; 1113 } 1114 #endif 1115 1116 /* 1117 * Check that the key type appears in the supplied pattern list, ignoring 1118 * mismatches in the signature algorithm. (Signature algorithm checks are 1119 * performed in the unprivileged authentication code). 1120 * Returns 1 on success, 0 otherwise. 1121 */ 1122 static int 1123 key_base_type_match(const char *method, const struct sshkey *key, 1124 const char *list) 1125 { 1126 char *s, *l, *ol = xstrdup(list); 1127 int found = 0; 1128 1129 l = ol; 1130 for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) { 1131 if (sshkey_type_from_name(s) == key->type) { 1132 found = 1; 1133 break; 1134 } 1135 } 1136 if (!found) { 1137 error("%s key type %s is not in permitted list %s", method, 1138 sshkey_ssh_name(key), list); 1139 } 1140 1141 free(ol); 1142 return found; 1143 } 1144 1145 int 1146 mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m) 1147 { 1148 struct sshkey *key = NULL; 1149 char *cuser, *chost; 1150 u_int pubkey_auth_attempt; 1151 u_int type = 0; 1152 int r, allowed = 0; 1153 struct sshauthopt *opts = NULL; 1154 Authctxt *authctxt = ssh->authctxt; 1155 1156 debug3_f("entering"); 1157 if ((r = sshbuf_get_u32(m, &type)) != 0 || 1158 (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 || 1159 (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 || 1160 (r = sshkey_froms(m, &key)) != 0 || 1161 (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0) 1162 fatal_fr(r, "parse"); 1163 1164 if (key != NULL && authctxt->valid) { 1165 switch (type) { 1166 case MM_USERKEY: 1167 auth_method = "publickey"; 1168 if (!options.pubkey_authentication) 1169 break; 1170 if (auth2_key_already_used(authctxt, key)) 1171 break; 1172 if (!key_base_type_match(auth_method, key, 1173 options.pubkey_accepted_algos)) 1174 break; 1175 allowed = user_key_allowed(ssh, authctxt->pw, key, 1176 pubkey_auth_attempt, &opts); 1177 break; 1178 case MM_HOSTKEY: 1179 auth_method = "hostbased"; 1180 if (!options.hostbased_authentication) 1181 break; 1182 if (auth2_key_already_used(authctxt, key)) 1183 break; 1184 if (!key_base_type_match(auth_method, key, 1185 options.hostbased_accepted_algos)) 1186 break; 1187 allowed = hostbased_key_allowed(ssh, authctxt->pw, 1188 cuser, chost, key); 1189 auth2_record_info(authctxt, 1190 "client user \"%.100s\", client host \"%.100s\"", 1191 cuser, chost); 1192 break; 1193 default: 1194 fatal_f("unknown key type %u", type); 1195 break; 1196 } 1197 } 1198 1199 debug3_f("%s authentication%s: %s key is %s", auth_method, 1200 pubkey_auth_attempt ? "" : " test", 1201 (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key), 1202 allowed ? "allowed" : "not allowed"); 1203 1204 auth2_record_key(authctxt, 0, key); 1205 1206 /* clear temporarily storage (used by verify) */ 1207 monitor_reset_key_state(); 1208 1209 if (allowed) { 1210 /* Save temporarily for comparison in verify */ 1211 if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0) 1212 fatal_fr(r, "sshkey_to_blob"); 1213 key_blobtype = type; 1214 key_opts = opts; 1215 hostbased_cuser = cuser; 1216 hostbased_chost = chost; 1217 } else { 1218 /* Log failed attempt */ 1219 auth_log(ssh, 0, 0, auth_method, NULL); 1220 pfilter_notify(1); 1221 free(cuser); 1222 free(chost); 1223 } 1224 sshkey_free(key); 1225 1226 sshbuf_reset(m); 1227 if ((r = sshbuf_put_u32(m, allowed)) != 0) 1228 fatal_fr(r, "assemble"); 1229 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0) 1230 fatal_fr(r, "sshauthopt_serialise"); 1231 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 1232 1233 if (!allowed) 1234 sshauthopt_free(opts); 1235 1236 return (0); 1237 } 1238 1239 static int 1240 monitor_valid_userblob(struct ssh *ssh, const u_char *data, u_int datalen) 1241 { 1242 struct sshbuf *b; 1243 struct sshkey *hostkey = NULL; 1244 const u_char *p; 1245 char *userstyle, *cp; 1246 size_t len; 1247 u_char type; 1248 int hostbound = 0, r, fail = 0; 1249 Authctxt *authctxt = ssh->authctxt; 1250 1251 if ((b = sshbuf_from(data, datalen)) == NULL) 1252 fatal_f("sshbuf_from"); 1253 1254 if (ssh->compat & SSH_OLD_SESSIONID) { 1255 p = sshbuf_ptr(b); 1256 len = sshbuf_len(b); 1257 if ((session_id2 == NULL) || 1258 (len < session_id2_len) || 1259 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1260 fail++; 1261 if ((r = sshbuf_consume(b, session_id2_len)) != 0) 1262 fatal_fr(r, "consume"); 1263 } else { 1264 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1265 fatal_fr(r, "parse sessionid"); 1266 if ((session_id2 == NULL) || 1267 (len != session_id2_len) || 1268 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1269 fail++; 1270 } 1271 if ((r = sshbuf_get_u8(b, &type)) != 0) 1272 fatal_fr(r, "parse type"); 1273 if (type != SSH2_MSG_USERAUTH_REQUEST) 1274 fail++; 1275 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1276 fatal_fr(r, "parse userstyle"); 1277 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1278 authctxt->style ? ":" : "", 1279 authctxt->style ? authctxt->style : ""); 1280 if (strcmp(userstyle, cp) != 0) { 1281 logit("wrong user name passed to monitor: " 1282 "expected %s != %.100s", userstyle, cp); 1283 fail++; 1284 } 1285 free(userstyle); 1286 free(cp); 1287 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1288 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1289 fatal_fr(r, "parse method"); 1290 if (strcmp("publickey", cp) != 0) { 1291 if (strcmp("publickey-hostbound-v00@openssh.com", cp) == 0) 1292 hostbound = 1; 1293 else 1294 fail++; 1295 } 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 (hostbound && (r = sshkey_froms(b, &hostkey)) != 0)) 1304 fatal_fr(r, "parse pk"); 1305 if (sshbuf_len(b) != 0) 1306 fail++; 1307 sshbuf_free(b); 1308 if (hostkey != NULL) { 1309 /* 1310 * Ensure this is actually one of our hostkeys; unfortunately 1311 * can't check ssh->kex->initial_hostkey directly at this point 1312 * as packet state has not yet been exported to monitor. 1313 */ 1314 if (get_hostkey_index(hostkey, 1, ssh) == -1) 1315 fatal_f("hostbound hostkey does not match"); 1316 sshkey_free(hostkey); 1317 } 1318 return (fail == 0); 1319 } 1320 1321 static int 1322 monitor_valid_hostbasedblob(struct ssh *ssh, const u_char *data, u_int datalen, 1323 const char *cuser, const char *chost) 1324 { 1325 struct sshbuf *b; 1326 const u_char *p; 1327 char *cp, *userstyle; 1328 size_t len; 1329 int r, fail = 0; 1330 u_char type; 1331 Authctxt *authctxt = ssh->authctxt; 1332 1333 if ((b = sshbuf_from(data, datalen)) == NULL) 1334 fatal_f("sshbuf_new"); 1335 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1336 fatal_fr(r, "parse sessionid"); 1337 1338 if ((session_id2 == NULL) || 1339 (len != session_id2_len) || 1340 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1341 fail++; 1342 1343 if ((r = sshbuf_get_u8(b, &type)) != 0) 1344 fatal_fr(r, "parse type"); 1345 if (type != SSH2_MSG_USERAUTH_REQUEST) 1346 fail++; 1347 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1348 fatal_fr(r, "parse userstyle"); 1349 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1350 authctxt->style ? ":" : "", 1351 authctxt->style ? authctxt->style : ""); 1352 if (strcmp(userstyle, cp) != 0) { 1353 logit("wrong user name passed to monitor: " 1354 "expected %s != %.100s", userstyle, cp); 1355 fail++; 1356 } 1357 free(userstyle); 1358 free(cp); 1359 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1360 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1361 fatal_fr(r, "parse method"); 1362 if (strcmp(cp, "hostbased") != 0) 1363 fail++; 1364 free(cp); 1365 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1366 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1367 fatal_fr(r, "parse pk"); 1368 1369 /* verify client host, strip trailing dot if necessary */ 1370 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1371 fatal_fr(r, "parse host"); 1372 if (((len = strlen(cp)) > 0) && cp[len - 1] == '.') 1373 cp[len - 1] = '\0'; 1374 if (strcmp(cp, chost) != 0) 1375 fail++; 1376 free(cp); 1377 1378 /* verify client user */ 1379 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1380 fatal_fr(r, "parse ruser"); 1381 if (strcmp(cp, cuser) != 0) 1382 fail++; 1383 free(cp); 1384 1385 if (sshbuf_len(b) != 0) 1386 fail++; 1387 sshbuf_free(b); 1388 return (fail == 0); 1389 } 1390 1391 int 1392 mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m) 1393 { 1394 struct sshkey *key; 1395 const u_char *signature, *data, *blob; 1396 char *sigalg = NULL, *fp = NULL; 1397 size_t signaturelen, datalen, bloblen; 1398 int r, ret, req_presence = 0, req_verify = 0, valid_data = 0; 1399 int encoded_ret; 1400 struct sshkey_sig_details *sig_details = NULL; 1401 Authctxt *authctxt = ssh->authctxt; 1402 1403 if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 || 1404 (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 || 1405 (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 || 1406 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0) 1407 fatal_fr(r, "parse"); 1408 1409 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1410 !monitor_allowed_key(blob, bloblen)) 1411 fatal_f("bad key, not previously allowed"); 1412 1413 /* Empty signature algorithm means NULL. */ 1414 if (*sigalg == '\0') { 1415 free(sigalg); 1416 sigalg = NULL; 1417 } 1418 1419 /* XXX use sshkey_froms here; need to change key_blob, etc. */ 1420 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0) 1421 fatal_fr(r, "parse key"); 1422 1423 switch (key_blobtype) { 1424 case MM_USERKEY: 1425 valid_data = monitor_valid_userblob(ssh, data, datalen); 1426 auth_method = "publickey"; 1427 break; 1428 case MM_HOSTKEY: 1429 valid_data = monitor_valid_hostbasedblob(ssh, data, datalen, 1430 hostbased_cuser, hostbased_chost); 1431 auth_method = "hostbased"; 1432 break; 1433 default: 1434 valid_data = 0; 1435 break; 1436 } 1437 if (!valid_data) 1438 fatal_f("bad %s signature data blob", 1439 key_blobtype == MM_USERKEY ? "userkey" : 1440 (key_blobtype == MM_HOSTKEY ? "hostkey" : "unknown")); 1441 1442 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 1443 SSH_FP_DEFAULT)) == NULL) 1444 fatal_f("sshkey_fingerprint failed"); 1445 1446 ret = sshkey_verify(key, signature, signaturelen, data, datalen, 1447 sigalg, ssh->compat, &sig_details); 1448 debug3_f("%s %s signature using %s %s%s%s", auth_method, 1449 sshkey_type(key), sigalg == NULL ? "default" : sigalg, 1450 (ret == 0) ? "verified" : "unverified", 1451 (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : ""); 1452 1453 if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) { 1454 req_presence = (options.pubkey_auth_options & 1455 PUBKEYAUTH_TOUCH_REQUIRED) || 1456 !key_opts->no_require_user_presence; 1457 if (req_presence && 1458 (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) { 1459 error("public key %s %s signature for %s%s from %.128s " 1460 "port %d rejected: user presence " 1461 "(authenticator touch) requirement not met ", 1462 sshkey_type(key), fp, 1463 authctxt->valid ? "" : "invalid user ", 1464 authctxt->user, ssh_remote_ipaddr(ssh), 1465 ssh_remote_port(ssh)); 1466 ret = SSH_ERR_SIGNATURE_INVALID; 1467 } 1468 req_verify = (options.pubkey_auth_options & 1469 PUBKEYAUTH_VERIFY_REQUIRED) || key_opts->require_verify; 1470 if (req_verify && 1471 (sig_details->sk_flags & SSH_SK_USER_VERIFICATION_REQD) == 0) { 1472 error("public key %s %s signature for %s%s from %.128s " 1473 "port %d rejected: user verification requirement " 1474 "not met ", sshkey_type(key), fp, 1475 authctxt->valid ? "" : "invalid user ", 1476 authctxt->user, ssh_remote_ipaddr(ssh), 1477 ssh_remote_port(ssh)); 1478 ret = SSH_ERR_SIGNATURE_INVALID; 1479 } 1480 } 1481 auth2_record_key(authctxt, ret == 0, key); 1482 1483 if (key_blobtype == MM_USERKEY) 1484 auth_activate_options(ssh, key_opts); 1485 monitor_reset_key_state(); 1486 1487 sshbuf_reset(m); 1488 1489 /* encode ret != 0 as positive integer, since we're sending u32 */ 1490 encoded_ret = (ret != 0); 1491 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 || 1492 (r = sshbuf_put_u8(m, sig_details != NULL)) != 0) 1493 fatal_fr(r, "assemble"); 1494 if (sig_details != NULL) { 1495 if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 || 1496 (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0) 1497 fatal_fr(r, "assemble sk"); 1498 } 1499 sshkey_sig_details_free(sig_details); 1500 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1501 1502 free(sigalg); 1503 free(fp); 1504 sshkey_free(key); 1505 1506 return ret == 0; 1507 } 1508 1509 static void 1510 mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw) 1511 { 1512 socklen_t fromlen; 1513 struct sockaddr_storage from; 1514 1515 /* 1516 * Get IP address of client. If the connection is not a socket, let 1517 * the address be 0.0.0.0. 1518 */ 1519 memset(&from, 0, sizeof(from)); 1520 fromlen = sizeof(from); 1521 if (ssh_packet_connection_is_on_socket(ssh)) { 1522 if (getpeername(ssh_packet_get_connection_in(ssh), 1523 (struct sockaddr *)&from, &fromlen) == -1) { 1524 debug("getpeername: %.100s", strerror(errno)); 1525 cleanup_exit(254); 1526 } 1527 } 1528 /* Record that there was a login on that tty from the remote host. */ 1529 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1530 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1531 (struct sockaddr *)&from, fromlen); 1532 } 1533 1534 static void 1535 mm_session_close(Session *s) 1536 { 1537 debug3_f("session %d pid %ld", s->self, (long)s->pid); 1538 if (s->ttyfd != -1) { 1539 debug3_f("tty %s ptyfd %d", s->tty, s->ptyfd); 1540 session_pty_cleanup2(s); 1541 } 1542 session_unused(s->self); 1543 } 1544 1545 int 1546 mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m) 1547 { 1548 extern struct monitor *pmonitor; 1549 Session *s; 1550 int r, res, fd0; 1551 Authctxt *authctxt = ssh->authctxt; 1552 1553 debug3_f("entering"); 1554 1555 sshbuf_reset(m); 1556 s = session_new(); 1557 if (s == NULL) 1558 goto error; 1559 s->authctxt = authctxt; 1560 s->pw = authctxt->pw; 1561 s->pid = pmonitor->m_pid; 1562 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1563 if (res == 0) 1564 goto error; 1565 pty_setowner(authctxt->pw, s->tty); 1566 1567 if ((r = sshbuf_put_u32(m, 1)) != 0 || 1568 (r = sshbuf_put_cstring(m, s->tty)) != 0) 1569 fatal_fr(r, "assemble"); 1570 1571 /* We need to trick ttyslot */ 1572 if (dup2(s->ttyfd, 0) == -1) 1573 fatal_f("dup2"); 1574 1575 mm_record_login(ssh, s, authctxt->pw); 1576 1577 /* Now we can close the file descriptor again */ 1578 close(0); 1579 1580 /* send messages generated by record_login */ 1581 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0) 1582 fatal_fr(r, "assemble loginmsg"); 1583 sshbuf_reset(loginmsg); 1584 1585 mm_request_send(sock, MONITOR_ANS_PTY, m); 1586 1587 if (mm_send_fd(sock, s->ptyfd) == -1 || 1588 mm_send_fd(sock, s->ttyfd) == -1) 1589 fatal_f("send fds failed"); 1590 1591 /* make sure nothing uses fd 0 */ 1592 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1593 fatal_f("open(/dev/null): %s", strerror(errno)); 1594 if (fd0 != 0) 1595 error_f("fd0 %d != 0", fd0); 1596 1597 /* slave side of pty is not needed */ 1598 close(s->ttyfd); 1599 s->ttyfd = s->ptyfd; 1600 /* no need to dup() because nobody closes ptyfd */ 1601 s->ptymaster = s->ptyfd; 1602 1603 debug3_f("tty %s ptyfd %d", s->tty, s->ttyfd); 1604 1605 return (0); 1606 1607 error: 1608 if (s != NULL) 1609 mm_session_close(s); 1610 if ((r = sshbuf_put_u32(m, 0)) != 0) 1611 fatal_fr(r, "assemble 0"); 1612 mm_request_send(sock, MONITOR_ANS_PTY, m); 1613 return (0); 1614 } 1615 1616 int 1617 mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m) 1618 { 1619 Session *s; 1620 char *tty; 1621 int r; 1622 1623 debug3_f("entering"); 1624 1625 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0) 1626 fatal_fr(r, "parse tty"); 1627 if ((s = session_by_tty(tty)) != NULL) 1628 mm_session_close(s); 1629 sshbuf_reset(m); 1630 free(tty); 1631 return (0); 1632 } 1633 1634 #ifdef KRB5 1635 int 1636 mm_answer_krb5(struct ssh *ssh, int xsocket, struct sshbuf *m) 1637 { 1638 krb5_data tkt, reply; 1639 char *client_user; 1640 unsigned char *data; 1641 size_t len; 1642 int r; 1643 int success; 1644 Authctxt *authctxt = ssh->authctxt; 1645 1646 /* use temporary var to avoid size issues on 64bit arch */ 1647 if ((r = sshbuf_get_string(m, &data, &len)) != 0) 1648 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1649 tkt.data = data; 1650 tkt.length = len; 1651 1652 success = options.kerberos_authentication && 1653 authctxt->valid && 1654 auth_krb5(ssh, &tkt, &client_user, &reply); 1655 1656 if (tkt.length) 1657 free(tkt.data); 1658 1659 sshbuf_reset(m); 1660 sshbuf_put_u32(m, success); 1661 1662 if (success) { 1663 sshbuf_put_cstring(m, client_user); 1664 sshbuf_put_string(m, reply.data, reply.length); 1665 if (client_user) 1666 free(client_user); 1667 if (reply.length) 1668 free(reply.data); 1669 } 1670 mm_request_send(xsocket, MONITOR_ANS_KRB5, m); 1671 1672 auth_method = "kerberos"; 1673 1674 return success; 1675 } 1676 #endif 1677 1678 int 1679 mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req) 1680 { 1681 extern struct monitor *pmonitor; 1682 int res, status; 1683 1684 debug3_f("tearing down sessions"); 1685 1686 /* The child is terminating */ 1687 session_destroy_all(ssh, &mm_session_close); 1688 1689 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1690 if (errno != EINTR) 1691 exit(1); 1692 1693 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1694 1695 /* Terminate process */ 1696 exit(res); 1697 } 1698 1699 void 1700 monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor) 1701 { 1702 ssh_clear_newkeys(ssh, MODE_IN); 1703 ssh_clear_newkeys(ssh, MODE_OUT); 1704 sshbuf_free(child_state); 1705 child_state = NULL; 1706 } 1707 1708 void 1709 monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor) 1710 { 1711 struct kex *kex; 1712 int r; 1713 1714 debug3_f("packet_set_state"); 1715 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1716 fatal_fr(r, "packet_set_state"); 1717 sshbuf_free(child_state); 1718 child_state = NULL; 1719 if ((kex = ssh->kex) == NULL) 1720 fatal_f("internal error: ssh->kex == NULL"); 1721 if (session_id2_len != sshbuf_len(ssh->kex->session_id)) { 1722 fatal_f("incorrect session id length %zu (expected %u)", 1723 sshbuf_len(ssh->kex->session_id), session_id2_len); 1724 } 1725 if (memcmp(sshbuf_ptr(ssh->kex->session_id), session_id2, 1726 session_id2_len) != 0) 1727 fatal_f("session ID mismatch"); 1728 /* XXX set callbacks */ 1729 #ifdef WITH_OPENSSL 1730 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server; 1731 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server; 1732 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server; 1733 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server; 1734 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server; 1735 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1736 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1737 kex->kex[KEX_ECDH_SHA2] = kex_gen_server; 1738 #endif 1739 kex->kex[KEX_C25519_SHA256] = kex_gen_server; 1740 kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server; 1741 kex->load_host_public_key=&get_hostkey_public_by_type; 1742 kex->load_host_private_key=&get_hostkey_private_by_type; 1743 kex->host_key_index=&get_hostkey_index; 1744 kex->sign = sshd_hostkey_sign; 1745 } 1746 1747 /* This function requires careful sanity checking */ 1748 1749 void 1750 mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor) 1751 { 1752 debug3_f("Waiting for new keys"); 1753 1754 if ((child_state = sshbuf_new()) == NULL) 1755 fatal_f("sshbuf_new failed"); 1756 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1757 child_state); 1758 debug3_f("GOT new keys"); 1759 } 1760 1761 1762 /* XXX */ 1763 1764 #define FD_CLOSEONEXEC(x) do { \ 1765 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1766 fatal("fcntl(%d, F_SETFD)", x); \ 1767 } while (0) 1768 1769 static void 1770 monitor_openfds(struct monitor *mon, int do_logfds) 1771 { 1772 int pair[2]; 1773 #ifdef SO_ZEROIZE 1774 int on = 1; 1775 #endif 1776 1777 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1778 fatal_f("socketpair: %s", strerror(errno)); 1779 #ifdef SO_ZEROIZE 1780 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1781 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno)); 1782 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1783 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno)); 1784 #endif 1785 FD_CLOSEONEXEC(pair[0]); 1786 FD_CLOSEONEXEC(pair[1]); 1787 mon->m_recvfd = pair[0]; 1788 mon->m_sendfd = pair[1]; 1789 1790 if (do_logfds) { 1791 if (pipe(pair) == -1) 1792 fatal_f("pipe: %s", strerror(errno)); 1793 FD_CLOSEONEXEC(pair[0]); 1794 FD_CLOSEONEXEC(pair[1]); 1795 mon->m_log_recvfd = pair[0]; 1796 mon->m_log_sendfd = pair[1]; 1797 } else 1798 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1799 } 1800 1801 #define MM_MEMSIZE 65536 1802 1803 struct monitor * 1804 monitor_init(void) 1805 { 1806 struct monitor *mon; 1807 1808 mon = xcalloc(1, sizeof(*mon)); 1809 monitor_openfds(mon, 1); 1810 1811 return mon; 1812 } 1813 1814 void 1815 monitor_reinit(struct monitor *mon) 1816 { 1817 monitor_openfds(mon, 0); 1818 } 1819 1820 #ifdef GSSAPI 1821 int 1822 mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1823 { 1824 gss_OID_desc goid; 1825 OM_uint32 major; 1826 size_t len; 1827 u_char *p; 1828 int r; 1829 1830 if (!options.gss_authentication) 1831 fatal_f("GSSAPI authentication not enabled"); 1832 1833 if ((r = sshbuf_get_string(m, &p, &len)) != 0) 1834 fatal_fr(r, "parse"); 1835 goid.elements = p; 1836 goid.length = len; 1837 1838 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1839 1840 free(goid.elements); 1841 1842 sshbuf_reset(m); 1843 if ((r = sshbuf_put_u32(m, major)) != 0) 1844 fatal_fr(r, "assemble"); 1845 1846 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1847 1848 /* Now we have a context, enable the step */ 1849 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1850 1851 return (0); 1852 } 1853 1854 int 1855 mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1856 { 1857 gss_buffer_desc in; 1858 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1859 OM_uint32 major, minor; 1860 OM_uint32 flags = 0; /* GSI needs this */ 1861 int r; 1862 1863 if (!options.gss_authentication) 1864 fatal_f("GSSAPI authentication not enabled"); 1865 1866 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0) 1867 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1868 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1869 free(in.value); 1870 1871 sshbuf_reset(m); 1872 if ((r = sshbuf_put_u32(m, major)) != 0 || 1873 (r = sshbuf_put_string(m, out.value, out.length)) != 0 || 1874 (r = sshbuf_put_u32(m, flags)) != 0) 1875 fatal_fr(r, "assemble"); 1876 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1877 1878 gss_release_buffer(&minor, &out); 1879 1880 if (major == GSS_S_COMPLETE) { 1881 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1882 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1883 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1884 } 1885 return (0); 1886 } 1887 1888 int 1889 mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m) 1890 { 1891 gss_buffer_desc gssbuf, mic; 1892 OM_uint32 ret; 1893 int r; 1894 1895 if (!options.gss_authentication) 1896 fatal_f("GSSAPI authentication not enabled"); 1897 1898 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 || 1899 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0) 1900 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1901 1902 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1903 1904 free(gssbuf.value); 1905 free(mic.value); 1906 1907 sshbuf_reset(m); 1908 if ((r = sshbuf_put_u32(m, ret)) != 0) 1909 fatal_fr(r, "assemble"); 1910 1911 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1912 1913 if (!GSS_ERROR(ret)) 1914 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1915 1916 return (0); 1917 } 1918 1919 int 1920 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m) 1921 { 1922 int r, authenticated; 1923 const char *displayname; 1924 Authctxt *authctxt = ssh->authctxt; 1925 1926 if (!options.gss_authentication) 1927 fatal_f("GSSAPI authentication not enabled"); 1928 1929 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1930 1931 sshbuf_reset(m); 1932 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 1933 fatal_fr(r, "assemble"); 1934 1935 debug3_f("sending result %d", authenticated); 1936 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1937 1938 auth_method = "gssapi-with-mic"; 1939 1940 if ((displayname = ssh_gssapi_displayname()) != NULL) 1941 auth2_record_info(authctxt, "%s", displayname); 1942 1943 /* Monitor loop will terminate if authenticated */ 1944 return (authenticated); 1945 } 1946 #endif /* GSSAPI */ 1947 1948