1 /* $NetBSD: monitor.c,v 1.45 2024/07/08 22:33:43 christos Exp $ */ 2 /* $OpenBSD: monitor.c,v 1.240 2024/06/06 17:15:25 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 1.45 2024/07/08 22:33:43 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 *); 120 121 #ifdef USE_PAM 122 int mm_answer_pam_start(struct ssh *, int, struct sshbuf *); 123 int mm_answer_pam_account(struct ssh *, int, struct sshbuf *); 124 int mm_answer_pam_init_ctx(struct ssh *, int, struct sshbuf *); 125 int mm_answer_pam_query(struct ssh *, int, struct sshbuf *); 126 int mm_answer_pam_respond(struct ssh *, int, struct sshbuf *); 127 int mm_answer_pam_free_ctx(struct ssh *, int, struct sshbuf *); 128 #endif 129 130 #ifdef KRB5 131 int mm_answer_krb5(struct ssh *, int, struct sshbuf *); 132 #endif 133 134 #ifdef GSSAPI 135 int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *); 136 int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *); 137 int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *); 138 int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *); 139 #endif 140 141 static Authctxt *authctxt; 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 int auth_attempted = 0; 156 157 struct mon_table { 158 enum monitor_reqtype type; 159 int flags; 160 int (*f)(struct ssh *, int, struct sshbuf *); 161 }; 162 163 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 164 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 165 #define MON_ONCE 0x0010 /* Disable after calling */ 166 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 167 168 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 169 170 #define MON_PERMIT 0x1000 /* Request is permitted */ 171 172 static int monitor_read(struct ssh *, struct monitor *, struct mon_table *, 173 struct mon_table **); 174 static int monitor_read_log(struct monitor *); 175 176 struct mon_table mon_dispatch_proto20[] = { 177 #ifdef WITH_OPENSSL 178 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 179 #endif 180 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 181 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 182 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 183 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 184 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 185 #ifdef USE_PAM 186 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 187 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 188 {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx}, 189 {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query}, 190 {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond}, 191 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 192 #endif 193 #ifdef BSD_AUTH 194 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 195 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 196 #endif 197 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 198 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 199 #ifdef KRB5 200 {MONITOR_REQ_KRB5, MON_ONCE|MON_AUTH, mm_answer_krb5}, 201 #endif 202 #ifdef GSSAPI 203 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 204 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx}, 205 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok}, 206 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic}, 207 #endif 208 {0, 0, NULL} 209 }; 210 211 struct mon_table mon_dispatch_postauth20[] = { 212 #ifdef WITH_OPENSSL 213 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 214 #endif 215 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 216 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 217 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 218 {MONITOR_REQ_TERM, 0, mm_answer_term}, 219 {0, 0, NULL} 220 }; 221 222 struct mon_table *mon_dispatch; 223 224 /* Specifies if a certain message is allowed at the moment */ 225 static void 226 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 227 { 228 while (ent->f != NULL) { 229 if (ent->type == type) { 230 ent->flags &= ~MON_PERMIT; 231 ent->flags |= permit ? MON_PERMIT : 0; 232 return; 233 } 234 ent++; 235 } 236 } 237 238 static void 239 monitor_permit_authentications(int permit) 240 { 241 struct mon_table *ent = mon_dispatch; 242 243 while (ent->f != NULL) { 244 if (ent->flags & MON_AUTH) { 245 ent->flags &= ~MON_PERMIT; 246 ent->flags |= permit ? MON_PERMIT : 0; 247 } 248 ent++; 249 } 250 } 251 252 void 253 monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor) 254 { 255 struct mon_table *ent; 256 int authenticated = 0, partial = 0; 257 258 debug3("preauth child monitor started"); 259 260 authctxt = (Authctxt *)ssh->authctxt; 261 if (pmonitor->m_recvfd >= 0) 262 close(pmonitor->m_recvfd); 263 if (pmonitor->m_log_sendfd >= 0) 264 close(pmonitor->m_log_sendfd); 265 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 266 267 memset(authctxt, 0, sizeof(*authctxt)); 268 ssh->authctxt = authctxt; 269 270 mon_dispatch = mon_dispatch_proto20; 271 /* Permit requests for moduli and signatures */ 272 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 273 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 274 275 /* The first few requests do not require asynchronous access */ 276 while (!authenticated) { 277 partial = 0; 278 auth_method = "unknown"; 279 auth_submethod = NULL; 280 auth2_authctxt_reset_info(authctxt); 281 282 authenticated = (monitor_read(ssh, pmonitor, 283 mon_dispatch, &ent) == 1); 284 285 /* Record that auth was attempted to set exit status later */ 286 if ((ent->flags & MON_AUTH) != 0) 287 auth_attempted = 1; 288 289 /* Special handling for multiple required authentications */ 290 if (options.num_auth_methods != 0) { 291 if (authenticated && 292 !auth2_update_methods_lists(authctxt, 293 auth_method, auth_submethod)) { 294 debug3_f("method %s: partial", auth_method); 295 authenticated = 0; 296 partial = 1; 297 } 298 } 299 300 if (authenticated) { 301 if (!(ent->flags & MON_AUTHDECIDE)) 302 fatal_f("unexpected authentication from %d", 303 ent->type); 304 if (authctxt->pw->pw_uid == 0 && 305 !auth_root_allowed(ssh, auth_method)) 306 authenticated = 0; 307 #ifdef USE_PAM 308 /* PAM needs to perform account checks after auth */ 309 if (options.use_pam && authenticated) { 310 struct sshbuf *m; 311 312 if ((m = sshbuf_new()) == NULL) 313 fatal("%s: sshbuf_new failed", __func__); 314 315 mm_request_receive_expect(pmonitor->m_sendfd, 316 MONITOR_REQ_PAM_ACCOUNT, m); 317 authenticated = mm_answer_pam_account(ssh, pmonitor->m_sendfd, m); 318 sshbuf_free(m); 319 } 320 #endif 321 } 322 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 323 auth_log(ssh, authenticated, partial, 324 auth_method, auth_submethod); 325 if (!partial && !authenticated) 326 authctxt->failures++; 327 if (authenticated || partial) { 328 auth2_update_session_info(authctxt, 329 auth_method, auth_submethod); 330 } 331 } 332 if (authctxt->failures > options.max_authtries) { 333 pfilter_notify(1); 334 /* Shouldn't happen */ 335 fatal_f("privsep child made too many authentication " 336 "attempts"); 337 } 338 } 339 340 if (!authctxt->valid) { 341 pfilter_notify(1); 342 fatal_f("authenticated invalid user"); 343 } 344 if (strcmp(auth_method, "unknown") == 0) { 345 pfilter_notify(1); 346 fatal_f("authentication method name unknown"); 347 } 348 349 debug_f("user %s authenticated by privileged process", authctxt->user); 350 auth_attempted = 0; 351 ssh->authctxt = NULL; 352 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 353 354 mm_get_keystate(ssh, pmonitor); 355 356 /* Drain any buffered messages from the child */ 357 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 358 ; 359 360 if (pmonitor->m_recvfd >= 0) 361 close(pmonitor->m_recvfd); 362 if (pmonitor->m_log_sendfd >= 0) 363 close(pmonitor->m_log_sendfd); 364 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 365 } 366 367 static void 368 monitor_set_child_handler(pid_t pid) 369 { 370 monitor_child_pid = pid; 371 } 372 373 static void 374 monitor_child_handler(int sig) 375 { 376 kill(monitor_child_pid, sig); 377 } 378 379 void 380 monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor) 381 { 382 close(pmonitor->m_recvfd); 383 pmonitor->m_recvfd = -1; 384 385 monitor_set_child_handler(pmonitor->m_pid); 386 ssh_signal(SIGHUP, &monitor_child_handler); 387 ssh_signal(SIGTERM, &monitor_child_handler); 388 ssh_signal(SIGINT, &monitor_child_handler); 389 390 mon_dispatch = mon_dispatch_postauth20; 391 392 /* Permit requests for moduli and signatures */ 393 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 394 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 395 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 396 397 if (auth_opts->permit_pty_flag) { 398 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 399 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 400 } 401 402 for (;;) 403 monitor_read(ssh, pmonitor, mon_dispatch, NULL); 404 } 405 406 static int 407 monitor_read_log(struct monitor *pmonitor) 408 { 409 struct sshbuf *logmsg; 410 u_int len, level, forced; 411 char *msg; 412 u_char *p; 413 int r; 414 415 if ((logmsg = sshbuf_new()) == NULL) 416 fatal_f("sshbuf_new"); 417 418 /* Read length */ 419 if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0) 420 fatal_fr(r, "reserve len"); 421 if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) { 422 if (errno == EPIPE) { 423 sshbuf_free(logmsg); 424 debug_f("child log fd closed"); 425 close(pmonitor->m_log_recvfd); 426 pmonitor->m_log_recvfd = -1; 427 return -1; 428 } 429 fatal_f("log fd read: %s", strerror(errno)); 430 } 431 if ((r = sshbuf_get_u32(logmsg, &len)) != 0) 432 fatal_fr(r, "parse len"); 433 if (len <= 4 || len > 8192) 434 fatal_f("invalid log message length %u", len); 435 436 /* Read severity, message */ 437 sshbuf_reset(logmsg); 438 if ((r = sshbuf_reserve(logmsg, len, &p)) != 0) 439 fatal_fr(r, "reserve msg"); 440 if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len) 441 fatal_f("log fd read: %s", strerror(errno)); 442 if ((r = sshbuf_get_u32(logmsg, &level)) != 0 || 443 (r = sshbuf_get_u32(logmsg, &forced)) != 0 || 444 (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0) 445 fatal_fr(r, "parse"); 446 447 /* Log it */ 448 if (log_level_name(level) == NULL) 449 fatal_f("invalid log level %u (corrupted message?)", level); 450 sshlogdirect(level, forced, "%s [preauth]", msg); 451 452 sshbuf_free(logmsg); 453 free(msg); 454 455 return 0; 456 } 457 458 static int 459 monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent, 460 struct mon_table **pent) 461 { 462 struct sshbuf *m; 463 int r, ret; 464 u_char type; 465 struct pollfd pfd[2]; 466 467 for (;;) { 468 memset(&pfd, 0, sizeof(pfd)); 469 pfd[0].fd = pmonitor->m_sendfd; 470 pfd[0].events = POLLIN; 471 pfd[1].fd = pmonitor->m_log_recvfd; 472 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 473 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 474 if (errno == EINTR || errno == EAGAIN) 475 continue; 476 fatal_f("poll: %s", strerror(errno)); 477 } 478 if (pfd[1].revents) { 479 /* 480 * Drain all log messages before processing next 481 * monitor request. 482 */ 483 monitor_read_log(pmonitor); 484 continue; 485 } 486 if (pfd[0].revents) 487 break; /* Continues below */ 488 } 489 490 if ((m = sshbuf_new()) == NULL) 491 fatal_f("sshbuf_new"); 492 493 mm_request_receive(pmonitor->m_sendfd, m); 494 if ((r = sshbuf_get_u8(m, &type)) != 0) 495 fatal_fr(r, "parse type"); 496 497 debug3_f("checking request %d", type); 498 499 while (ent->f != NULL) { 500 if (ent->type == type) 501 break; 502 ent++; 503 } 504 505 if (ent->f != NULL) { 506 if (!(ent->flags & MON_PERMIT)) 507 fatal_f("unpermitted request %d", type); 508 ret = (*ent->f)(ssh, pmonitor->m_sendfd, m); 509 sshbuf_free(m); 510 511 /* The child may use this request only once, disable it */ 512 if (ent->flags & MON_ONCE) { 513 debug2_f("%d used once, disabling now", type); 514 ent->flags &= ~MON_PERMIT; 515 } 516 517 if (pent != NULL) 518 *pent = ent; 519 520 return ret; 521 } 522 523 fatal_f("unsupported request: %d", type); 524 525 /* NOTREACHED */ 526 return (-1); 527 } 528 529 /* allowed key state */ 530 static int 531 monitor_allowed_key(const u_char *blob, u_int bloblen) 532 { 533 /* make sure key is allowed */ 534 if (key_blob == NULL || key_bloblen != bloblen || 535 timingsafe_bcmp(key_blob, blob, key_bloblen)) 536 return (0); 537 return (1); 538 } 539 540 static void 541 monitor_reset_key_state(void) 542 { 543 /* reset state */ 544 free(key_blob); 545 free(hostbased_cuser); 546 free(hostbased_chost); 547 sshauthopt_free(key_opts); 548 key_blob = NULL; 549 key_bloblen = 0; 550 key_blobtype = MM_NOKEY; 551 key_opts = NULL; 552 hostbased_cuser = NULL; 553 hostbased_chost = NULL; 554 } 555 556 #ifdef WITH_OPENSSL 557 int 558 mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m) 559 { 560 DH *dh; 561 const BIGNUM *dh_p, *dh_g; 562 int r; 563 u_int min, want, max; 564 565 if ((r = sshbuf_get_u32(m, &min)) != 0 || 566 (r = sshbuf_get_u32(m, &want)) != 0 || 567 (r = sshbuf_get_u32(m, &max)) != 0) 568 fatal_fr(r, "parse"); 569 570 debug3_f("got parameters: %d %d %d", min, want, max); 571 /* We need to check here, too, in case the child got corrupted */ 572 if (max < min || want < min || max < want) 573 fatal_f("bad parameters: %d %d %d", min, want, max); 574 575 sshbuf_reset(m); 576 577 dh = choose_dh(min, want, max); 578 if (dh == NULL) { 579 if ((r = sshbuf_put_u8(m, 0)) != 0) 580 fatal_fr(r, "assemble empty"); 581 return (0); 582 } else { 583 /* Send first bignum */ 584 DH_get0_pqg(dh, &dh_p, NULL, &dh_g); 585 if ((r = sshbuf_put_u8(m, 1)) != 0 || 586 (r = sshbuf_put_bignum2(m, dh_p)) != 0 || 587 (r = sshbuf_put_bignum2(m, dh_g)) != 0) 588 fatal_fr(r, "assemble"); 589 590 DH_free(dh); 591 } 592 mm_request_send(sock, MONITOR_ANS_MODULI, m); 593 return (0); 594 } 595 #endif 596 597 int 598 mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m) 599 { 600 extern int auth_sock; /* XXX move to state struct? */ 601 struct sshkey *key; 602 struct sshbuf *sigbuf = NULL; 603 u_char *p = NULL, *signature = NULL; 604 char *alg = NULL; 605 size_t datlen, siglen, alglen; 606 int r, is_proof = 0; 607 u_int keyid, compat; 608 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 609 610 debug3_f("entering"); 611 612 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 613 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 614 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0 || 615 (r = sshbuf_get_u32(m, &compat)) != 0) 616 fatal_fr(r, "parse"); 617 if (keyid > INT_MAX) 618 fatal_f("invalid key ID"); 619 620 /* 621 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 622 * SHA384 (48 bytes) and SHA512 (64 bytes). 623 * 624 * Otherwise, verify the signature request is for a hostkey 625 * proof. 626 * 627 * XXX perform similar check for KEX signature requests too? 628 * it's not trivial, since what is signed is the hash, rather 629 * than the full kex structure... 630 */ 631 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 632 /* 633 * Construct expected hostkey proof and compare it to what 634 * the client sent us. 635 */ 636 if (session_id2_len == 0) /* hostkeys is never first */ 637 fatal_f("bad data length: %zu", datlen); 638 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 639 fatal_f("no hostkey for index %d", keyid); 640 if ((sigbuf = sshbuf_new()) == NULL) 641 fatal_f("sshbuf_new"); 642 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 643 (r = sshbuf_put_string(sigbuf, session_id2, 644 session_id2_len)) != 0 || 645 (r = sshkey_puts(key, sigbuf)) != 0) 646 fatal_fr(r, "assemble private key proof"); 647 if (datlen != sshbuf_len(sigbuf) || 648 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 649 fatal_f("bad data length: %zu, hostkey proof len %zu", 650 datlen, sshbuf_len(sigbuf)); 651 sshbuf_free(sigbuf); 652 is_proof = 1; 653 } 654 655 /* save session id, it will be passed on the first call */ 656 if (session_id2_len == 0) { 657 session_id2_len = datlen; 658 session_id2 = xmalloc(session_id2_len); 659 memcpy(session_id2, p, session_id2_len); 660 } 661 662 if ((key = get_hostkey_by_index(keyid)) != NULL) { 663 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 664 options.sk_provider, NULL, compat)) != 0) 665 fatal_fr(r, "sign"); 666 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 667 auth_sock > 0) { 668 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 669 p, datlen, alg, compat)) != 0) 670 fatal_fr(r, "agent sign"); 671 } else 672 fatal_f("no hostkey from index %d", keyid); 673 674 debug3_f("%s %s signature len=%zu", alg, 675 is_proof ? "hostkey proof" : "KEX", siglen); 676 677 sshbuf_reset(m); 678 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 679 fatal_fr(r, "assemble"); 680 681 free(alg); 682 free(p); 683 free(signature); 684 685 mm_request_send(sock, MONITOR_ANS_SIGN, m); 686 687 /* Turn on permissions for getpwnam */ 688 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 689 690 return (0); 691 } 692 693 #define PUTPW(b, id) \ 694 do { \ 695 if ((r = sshbuf_put_string(b, \ 696 &pwent->id, sizeof(pwent->id))) != 0) \ 697 fatal_fr(r, "assemble %s", #id); \ 698 } while (0) 699 700 void 701 mm_encode_server_options(struct sshbuf *m) 702 { 703 int r; 704 u_int i; 705 706 /* XXX this leaks raw pointers to the unpriv child processes */ 707 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0) 708 fatal_fr(r, "assemble options"); 709 710 #define M_CP_STROPT(x) do { \ 711 if (options.x != NULL && \ 712 (r = sshbuf_put_cstring(m, options.x)) != 0) \ 713 fatal_fr(r, "assemble %s", #x); \ 714 } while (0) 715 #define M_CP_STRARRAYOPT(x, nx) do { \ 716 for (i = 0; i < options.nx; i++) { \ 717 if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \ 718 fatal_fr(r, "assemble %s", #x); \ 719 } \ 720 } while (0) 721 /* See comment in servconf.h */ 722 COPY_MATCH_STRING_OPTS(); 723 #undef M_CP_STROPT 724 #undef M_CP_STRARRAYOPT 725 } 726 727 /* Retrieves the password entry and also checks if the user is permitted */ 728 int 729 mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m) 730 { 731 struct passwd *pwent; 732 int r, allowed = 0; 733 734 debug3_f("entering"); 735 736 if (authctxt->attempt++ != 0) 737 fatal_f("multiple attempts for getpwnam"); 738 739 if ((r = sshbuf_get_cstring(m, &authctxt->user, NULL)) != 0) 740 fatal_fr(r, "parse"); 741 742 pwent = getpwnamallow(ssh, authctxt->user); 743 744 setproctitle("%s [priv]", pwent ? authctxt->user : "unknown"); 745 746 sshbuf_reset(m); 747 748 if (pwent == NULL) { 749 if ((r = sshbuf_put_u8(m, 0)) != 0) 750 fatal_fr(r, "assemble fakepw"); 751 authctxt->pw = fakepw(); 752 goto out; 753 } 754 755 allowed = 1; 756 authctxt->pw = pwent; 757 authctxt->valid = 1; 758 759 /* XXX send fake class/dir/shell, etc. */ 760 if ((r = sshbuf_put_u8(m, 1)) != 0) 761 fatal_fr(r, "assemble ok"); 762 PUTPW(m, pw_uid); 763 PUTPW(m, pw_gid); 764 PUTPW(m, pw_change); 765 PUTPW(m, pw_expire); 766 if ((r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || 767 (r = sshbuf_put_cstring(m, "*")) != 0 || 768 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 || 769 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 || 770 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 || 771 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0) 772 fatal_fr(r, "assemble pw"); 773 774 out: 775 ssh_packet_set_log_preamble(ssh, "%suser %s", 776 authctxt->valid ? "authenticating" : "invalid ", authctxt->user); 777 778 /* Send active options to unpriv */ 779 mm_encode_server_options(m); 780 781 /* Create valid auth method lists */ 782 if (auth2_setup_methods_lists(authctxt) != 0) { 783 /* 784 * The monitor will continue long enough to let the child 785 * run to its packet_disconnect(), but it must not allow any 786 * authentication to succeed. 787 */ 788 debug_f("no valid authentication method lists"); 789 } 790 791 debug3_f("sending MONITOR_ANS_PWNAM: %d", allowed); 792 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 793 794 /* Allow service/style information on the auth context */ 795 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 796 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 797 798 #ifdef USE_PAM 799 if (options.use_pam) 800 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); 801 #endif 802 803 return (0); 804 } 805 806 int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m) 807 { 808 char *banner; 809 int r; 810 811 sshbuf_reset(m); 812 banner = auth2_read_banner(); 813 if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0) 814 fatal_fr(r, "assemble"); 815 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 816 free(banner); 817 818 return (0); 819 } 820 821 int 822 mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m) 823 { 824 int r; 825 826 monitor_permit_authentications(1); 827 828 if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 || 829 (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0) 830 fatal_fr(r, "parse"); 831 debug3_f("service=%s, style=%s", authctxt->service, authctxt->style); 832 833 if (strlen(authctxt->style) == 0) { 834 free(authctxt->style); 835 authctxt->style = NULL; 836 } 837 838 return (0); 839 } 840 841 int 842 mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m) 843 { 844 static int call_count; 845 char *passwd; 846 int r, authenticated; 847 size_t plen; 848 849 if (!options.password_authentication) 850 fatal_f("password authentication not enabled"); 851 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0) 852 fatal_fr(r, "parse"); 853 /* Only authenticate if the context is valid */ 854 authenticated = options.password_authentication && 855 auth_password(ssh, passwd); 856 freezero(passwd, plen); 857 858 sshbuf_reset(m); 859 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 860 fatal_fr(r, "assemble"); 861 #ifdef USE_PAM 862 if ((r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0) 863 fatal_fr(r, "assemble PAM"); 864 #endif 865 debug3_f("sending result %d", authenticated); 866 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 867 868 call_count++; 869 if (plen == 0 && call_count == 1) 870 auth_method = "none"; 871 else 872 auth_method = "password"; 873 874 /* Causes monitor loop to terminate if authenticated */ 875 return (authenticated); 876 } 877 878 #ifdef BSD_AUTH 879 int 880 mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m) 881 { 882 char *name, *infotxt; 883 u_int numprompts, *echo_on, success; 884 char **prompts; 885 int r; 886 887 if (!options.kbd_interactive_authentication) 888 fatal_f("kbd-int authentication not enabled"); 889 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 890 &prompts, &echo_on) < 0 ? 0 : 1; 891 892 sshbuf_reset(m); 893 if ((r = sshbuf_put_u32(m, success)) != 0) 894 fatal_fr(r, "assemble"); 895 if (success) { 896 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0) 897 fatal_fr(r, "assemble prompt"); 898 } 899 900 debug3_f("sending challenge success: %u", success); 901 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 902 903 if (success) { 904 free(name); 905 free(infotxt); 906 free(prompts); 907 free(echo_on); 908 } 909 910 return (0); 911 } 912 913 int 914 mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m) 915 { 916 char *response; 917 int r, authok; 918 919 if (!options.kbd_interactive_authentication) 920 fatal_f("kbd-int authentication not enabled"); 921 if (authctxt->as == NULL) 922 fatal_f("no bsd auth session"); 923 924 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 925 fatal_fr(r, "parse"); 926 authok = options.kbd_interactive_authentication && 927 auth_userresponse(authctxt->as, response, 0); 928 authctxt->as = NULL; 929 debug3_f("<%s> = <%d>", response, authok); 930 free(response); 931 932 sshbuf_reset(m); 933 if ((r = sshbuf_put_u32(m, authok)) != 0) 934 fatal_fr(r, "assemble"); 935 936 debug3_f("sending authenticated: %d", authok); 937 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 938 939 auth_method = "keyboard-interactive"; 940 auth_submethod = "bsdauth"; 941 942 return (authok != 0); 943 } 944 #endif 945 946 #ifdef SKEY 947 int 948 mm_answer_skeyquery(int sock, struct sshbuf *m) 949 { 950 struct skey skey; 951 char challenge[1024]; 952 u_int success; 953 954 success = skeychallenge(&skey, authctxt->user, challenge, 955 sizeof(challenge)) < 0 ? 0 : 1; 956 957 sshbuf_reset(m); 958 sshbuf_put_int(m, success); 959 if (success) 960 sshbuf_put_cstring(m, challenge); 961 962 debug3("%s: sending challenge success: %u", __func__, success); 963 mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m); 964 965 return (0); 966 } 967 968 int 969 mm_answer_skeyrespond(int sock, struct sshbuf *m) 970 { 971 char *response; 972 int authok; 973 int r; 974 975 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 976 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 977 978 authok = (options.kbd_interactive_authentication && 979 authctxt->valid && 980 skey_haskey(authctxt->pw->pw_name) == 0 && 981 skey_passcheck(authctxt->pw->pw_name, response) != -1); 982 983 free(response); 984 985 sshbuf_reset(m); 986 sshbuf_put_int(m, authok); 987 988 debug3("%s: sending authenticated: %d", __func__, authok); 989 mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m); 990 991 auth_method = "skey"; 992 auth_submethod = "bsdauth"; 993 994 return (authok != 0); 995 } 996 #endif 997 998 #ifdef USE_PAM 999 int 1000 mm_answer_pam_start(struct ssh *ssh, int sock, struct sshbuf *m) 1001 { 1002 if (!options.use_pam) 1003 fatal("UsePAM not set, but ended up in %s anyway", __func__); 1004 1005 start_pam(ssh); 1006 1007 if (options.kbd_interactive_authentication) 1008 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); 1009 1010 return (0); 1011 } 1012 1013 int 1014 mm_answer_pam_account(struct ssh *ssh, int sock, struct sshbuf *m) 1015 { 1016 u_int ret; 1017 int r; 1018 1019 if (!options.use_pam) 1020 fatal("UsePAM not set, but ended up in %s anyway", __func__); 1021 1022 ret = do_pam_account(); 1023 1024 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1025 (r = sshbuf_put_stringb(m, loginmsg)) != 0) 1026 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1027 1028 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m); 1029 1030 return (ret); 1031 } 1032 1033 static void *sshpam_ctxt, *sshpam_authok; 1034 extern KbdintDevice sshpam_device; 1035 1036 int 1037 mm_answer_pam_init_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1038 { 1039 u_int ok = 0; 1040 int r; 1041 1042 debug3("%s", __func__); 1043 if (!options.kbd_interactive_authentication) 1044 fatal("%s: kbd-int authentication not enabled", __func__); 1045 if (sshpam_ctxt != NULL) 1046 fatal("%s: already called", __func__); 1047 sshpam_ctxt = (sshpam_device.init_ctx)(ssh->authctxt); 1048 sshpam_authok = NULL; 1049 sshbuf_reset(m); 1050 if (sshpam_ctxt != NULL) { 1051 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 1052 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_QUERY, 1); 1053 ok = 1; 1054 } 1055 if ((r = sshbuf_put_u32(m, ok)) != 0) 1056 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1057 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); 1058 return (0); 1059 } 1060 1061 int 1062 mm_answer_pam_query(struct ssh *ssh, int sock, struct sshbuf *m) 1063 { 1064 char *name, *info, **prompts; 1065 u_int i, num, *echo_on; 1066 int r, ret; 1067 1068 debug3("%s", __func__); 1069 sshpam_authok = NULL; 1070 if (sshpam_ctxt == NULL) 1071 fatal("%s: no context", __func__); 1072 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, 1073 &num, &prompts, &echo_on); 1074 if (ret == 0 && num == 0) 1075 sshpam_authok = sshpam_ctxt; 1076 if (num > 1 || name == NULL || info == NULL) 1077 fatal("sshpam_device.query failed"); 1078 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_RESPOND, 1); 1079 sshbuf_reset(m); 1080 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1081 (r = sshbuf_put_cstring(m, name)) != 0 || 1082 (r = sshbuf_put_cstring(m, info)) != 0 || 1083 (r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0 || 1084 (r = sshbuf_put_u32(m, num)) != 0) 1085 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1086 free(name); 1087 free(info); 1088 for (i = 0; i < num; ++i) { 1089 if ((r = sshbuf_put_cstring(m, prompts[i])) != 0 || 1090 (r = sshbuf_put_u32(m, echo_on[i])) != 0) 1091 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1092 free(prompts[i]); 1093 } 1094 free(prompts); 1095 free(echo_on); 1096 auth_method = "keyboard-interactive/pam"; 1097 auth_submethod = "pam"; 1098 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m); 1099 return (0); 1100 } 1101 1102 int 1103 mm_answer_pam_respond(struct ssh *ssh, int sock, struct sshbuf *m) 1104 { 1105 char **resp; 1106 u_int i, num; 1107 int r, ret; 1108 1109 debug3("%s", __func__); 1110 if (sshpam_ctxt == NULL) 1111 fatal("%s: no context", __func__); 1112 sshpam_authok = NULL; 1113 if ((r = sshbuf_get_u32(m, &num)) != 0) 1114 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1115 if (num > PAM_MAX_NUM_MSG) { 1116 fatal_f("Too many PAM messages, got %u, expected <= %u", 1117 num, (unsigned)PAM_MAX_NUM_MSG); 1118 } 1119 if (num > 0) { 1120 resp = xmalloc(num * sizeof(char *)); 1121 for (i = 0; i < num; ++i) 1122 if ((r = sshbuf_get_cstring(m, &resp[i], NULL)) != 0) 1123 fatal("%s: buffer error: %s", __func__, 1124 ssh_err(r)); 1125 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp); 1126 for (i = 0; i < num; ++i) 1127 free(resp[i]); 1128 free(resp); 1129 } else { 1130 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL); 1131 } 1132 sshbuf_reset(m); 1133 if ((r = sshbuf_put_u32(m, ret)) != 0) 1134 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1135 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m); 1136 auth_method = "keyboard-interactive/pam"; 1137 auth_submethod = "pam"; 1138 if (ret == 0) 1139 sshpam_authok = sshpam_ctxt; 1140 return (0); 1141 } 1142 1143 int 1144 mm_answer_pam_free_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1145 { 1146 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt; 1147 1148 debug3("%s", __func__); 1149 if (sshpam_ctxt == NULL) 1150 fatal("%s: no context", __func__); 1151 (sshpam_device.free_ctx)(sshpam_ctxt); 1152 sshpam_ctxt = sshpam_authok = NULL; 1153 sshbuf_reset(m); 1154 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); 1155 /* Allow another attempt */ 1156 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 1157 auth_method = "keyboard-interactive/pam"; 1158 auth_submethod = "pam"; 1159 return r; 1160 } 1161 #endif 1162 1163 /* 1164 * Check that the key type appears in the supplied pattern list, ignoring 1165 * mismatches in the signature algorithm. (Signature algorithm checks are 1166 * performed in the unprivileged authentication code). 1167 * Returns 1 on success, 0 otherwise. 1168 */ 1169 static int 1170 key_base_type_match(const char *method, const struct sshkey *key, 1171 const char *list) 1172 { 1173 char *s, *l, *ol = xstrdup(list); 1174 int found = 0; 1175 1176 l = ol; 1177 for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) { 1178 if (sshkey_type_from_name(s) == key->type) { 1179 found = 1; 1180 break; 1181 } 1182 } 1183 if (!found) { 1184 error("%s key type %s is not in permitted list %s", method, 1185 sshkey_ssh_name(key), list); 1186 } 1187 1188 free(ol); 1189 return found; 1190 } 1191 1192 int 1193 mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m) 1194 { 1195 struct sshkey *key = NULL; 1196 char *cuser, *chost; 1197 u_int pubkey_auth_attempt; 1198 u_int type = 0; 1199 int r, allowed = 0; 1200 struct sshauthopt *opts = NULL; 1201 1202 debug3_f("entering"); 1203 if ((r = sshbuf_get_u32(m, &type)) != 0 || 1204 (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 || 1205 (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 || 1206 (r = sshkey_froms(m, &key)) != 0 || 1207 (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0) 1208 fatal_fr(r, "parse"); 1209 1210 if (key != NULL && authctxt->valid) { 1211 switch (type) { 1212 case MM_USERKEY: 1213 auth_method = "publickey"; 1214 if (!options.pubkey_authentication) 1215 break; 1216 if (auth2_key_already_used(authctxt, key)) 1217 break; 1218 if (!key_base_type_match(auth_method, key, 1219 options.pubkey_accepted_algos)) 1220 break; 1221 allowed = user_key_allowed(ssh, authctxt->pw, key, 1222 pubkey_auth_attempt, &opts); 1223 break; 1224 case MM_HOSTKEY: 1225 auth_method = "hostbased"; 1226 if (!options.hostbased_authentication) 1227 break; 1228 if (auth2_key_already_used(authctxt, key)) 1229 break; 1230 if (!key_base_type_match(auth_method, key, 1231 options.hostbased_accepted_algos)) 1232 break; 1233 allowed = hostbased_key_allowed(ssh, authctxt->pw, 1234 cuser, chost, key); 1235 auth2_record_info(authctxt, 1236 "client user \"%.100s\", client host \"%.100s\"", 1237 cuser, chost); 1238 break; 1239 default: 1240 fatal_f("unknown key type %u", type); 1241 break; 1242 } 1243 } 1244 1245 debug3_f("%s authentication%s: %s key is %s", auth_method, 1246 pubkey_auth_attempt ? "" : " test", 1247 (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key), 1248 allowed ? "allowed" : "not allowed"); 1249 1250 auth2_record_key(authctxt, 0, key); 1251 1252 /* clear temporarily storage (used by verify) */ 1253 monitor_reset_key_state(); 1254 1255 if (allowed) { 1256 /* Save temporarily for comparison in verify */ 1257 if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0) 1258 fatal_fr(r, "sshkey_to_blob"); 1259 key_blobtype = type; 1260 key_opts = opts; 1261 hostbased_cuser = cuser; 1262 hostbased_chost = chost; 1263 } else { 1264 /* Log failed attempt */ 1265 auth_log(ssh, 0, 0, auth_method, NULL); 1266 pfilter_notify(1); 1267 free(cuser); 1268 free(chost); 1269 } 1270 sshkey_free(key); 1271 1272 sshbuf_reset(m); 1273 if ((r = sshbuf_put_u32(m, allowed)) != 0) 1274 fatal_fr(r, "assemble"); 1275 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0) 1276 fatal_fr(r, "sshauthopt_serialise"); 1277 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 1278 1279 if (!allowed) 1280 sshauthopt_free(opts); 1281 1282 return (0); 1283 } 1284 1285 static int 1286 monitor_valid_userblob(struct ssh *ssh, const u_char *data, u_int datalen) 1287 { 1288 struct sshbuf *b; 1289 struct sshkey *hostkey = NULL; 1290 const u_char *p; 1291 char *userstyle, *cp; 1292 size_t len; 1293 u_char type; 1294 int hostbound = 0, r, fail = 0; 1295 1296 if ((b = sshbuf_from(data, datalen)) == NULL) 1297 fatal_f("sshbuf_from"); 1298 1299 if (ssh->compat & SSH_OLD_SESSIONID) { 1300 p = sshbuf_ptr(b); 1301 len = sshbuf_len(b); 1302 if ((session_id2 == NULL) || 1303 (len < session_id2_len) || 1304 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1305 fail++; 1306 if ((r = sshbuf_consume(b, session_id2_len)) != 0) 1307 fatal_fr(r, "consume"); 1308 } else { 1309 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1310 fatal_fr(r, "parse sessionid"); 1311 if ((session_id2 == NULL) || 1312 (len != session_id2_len) || 1313 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1314 fail++; 1315 } 1316 if ((r = sshbuf_get_u8(b, &type)) != 0) 1317 fatal_fr(r, "parse type"); 1318 if (type != SSH2_MSG_USERAUTH_REQUEST) 1319 fail++; 1320 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1321 fatal_fr(r, "parse userstyle"); 1322 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1323 authctxt->style ? ":" : "", 1324 authctxt->style ? authctxt->style : ""); 1325 if (strcmp(userstyle, cp) != 0) { 1326 logit("wrong user name passed to monitor: " 1327 "expected %s != %.100s", userstyle, cp); 1328 fail++; 1329 } 1330 free(userstyle); 1331 free(cp); 1332 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1333 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1334 fatal_fr(r, "parse method"); 1335 if (strcmp("publickey", cp) != 0) { 1336 if (strcmp("publickey-hostbound-v00@openssh.com", cp) == 0) 1337 hostbound = 1; 1338 else 1339 fail++; 1340 } 1341 free(cp); 1342 if ((r = sshbuf_get_u8(b, &type)) != 0) 1343 fatal_fr(r, "parse pktype"); 1344 if (type == 0) 1345 fail++; 1346 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1347 (r = sshbuf_skip_string(b)) != 0 || /* pkblob */ 1348 (hostbound && (r = sshkey_froms(b, &hostkey)) != 0)) 1349 fatal_fr(r, "parse pk"); 1350 if (sshbuf_len(b) != 0) 1351 fail++; 1352 sshbuf_free(b); 1353 if (hostkey != NULL) { 1354 /* 1355 * Ensure this is actually one of our hostkeys; unfortunately 1356 * can't check ssh->kex->initial_hostkey directly at this point 1357 * as packet state has not yet been exported to monitor. 1358 */ 1359 if (get_hostkey_index(hostkey, 1, ssh) == -1) 1360 fatal_f("hostbound hostkey does not match"); 1361 sshkey_free(hostkey); 1362 } 1363 return (fail == 0); 1364 } 1365 1366 static int 1367 monitor_valid_hostbasedblob(struct ssh *ssh, const u_char *data, u_int datalen, 1368 const char *cuser, const char *chost) 1369 { 1370 struct sshbuf *b; 1371 const u_char *p; 1372 char *cp, *userstyle; 1373 size_t len; 1374 int r, fail = 0; 1375 u_char type; 1376 1377 if ((b = sshbuf_from(data, datalen)) == NULL) 1378 fatal_f("sshbuf_new"); 1379 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1380 fatal_fr(r, "parse sessionid"); 1381 1382 if ((session_id2 == NULL) || 1383 (len != session_id2_len) || 1384 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1385 fail++; 1386 1387 if ((r = sshbuf_get_u8(b, &type)) != 0) 1388 fatal_fr(r, "parse type"); 1389 if (type != SSH2_MSG_USERAUTH_REQUEST) 1390 fail++; 1391 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1392 fatal_fr(r, "parse userstyle"); 1393 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1394 authctxt->style ? ":" : "", 1395 authctxt->style ? authctxt->style : ""); 1396 if (strcmp(userstyle, cp) != 0) { 1397 logit("wrong user name passed to monitor: " 1398 "expected %s != %.100s", userstyle, cp); 1399 fail++; 1400 } 1401 free(userstyle); 1402 free(cp); 1403 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1404 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1405 fatal_fr(r, "parse method"); 1406 if (strcmp(cp, "hostbased") != 0) 1407 fail++; 1408 free(cp); 1409 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1410 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1411 fatal_fr(r, "parse pk"); 1412 1413 /* verify client host, strip trailing dot if necessary */ 1414 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1415 fatal_fr(r, "parse host"); 1416 if (((len = strlen(cp)) > 0) && cp[len - 1] == '.') 1417 cp[len - 1] = '\0'; 1418 if (strcmp(cp, chost) != 0) 1419 fail++; 1420 free(cp); 1421 1422 /* verify client user */ 1423 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1424 fatal_fr(r, "parse ruser"); 1425 if (strcmp(cp, cuser) != 0) 1426 fail++; 1427 free(cp); 1428 1429 if (sshbuf_len(b) != 0) 1430 fail++; 1431 sshbuf_free(b); 1432 return (fail == 0); 1433 } 1434 1435 int 1436 mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m) 1437 { 1438 struct sshkey *key; 1439 const u_char *signature, *data, *blob; 1440 char *sigalg = NULL, *fp = NULL; 1441 size_t signaturelen, datalen, bloblen; 1442 int r, ret, req_presence = 0, req_verify = 0, valid_data = 0; 1443 int encoded_ret; 1444 struct sshkey_sig_details *sig_details = NULL; 1445 1446 if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 || 1447 (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 || 1448 (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 || 1449 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0) 1450 fatal_fr(r, "parse"); 1451 1452 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1453 !monitor_allowed_key(blob, bloblen)) 1454 fatal_f("bad key, not previously allowed"); 1455 1456 /* Empty signature algorithm means NULL. */ 1457 if (*sigalg == '\0') { 1458 free(sigalg); 1459 sigalg = NULL; 1460 } 1461 1462 /* XXX use sshkey_froms here; need to change key_blob, etc. */ 1463 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0) 1464 fatal_fr(r, "parse key"); 1465 1466 switch (key_blobtype) { 1467 case MM_USERKEY: 1468 valid_data = monitor_valid_userblob(ssh, data, datalen); 1469 auth_method = "publickey"; 1470 break; 1471 case MM_HOSTKEY: 1472 valid_data = monitor_valid_hostbasedblob(ssh, data, datalen, 1473 hostbased_cuser, hostbased_chost); 1474 auth_method = "hostbased"; 1475 break; 1476 default: 1477 valid_data = 0; 1478 break; 1479 } 1480 if (!valid_data) 1481 fatal_f("bad %s signature data blob", 1482 key_blobtype == MM_USERKEY ? "userkey" : 1483 (key_blobtype == MM_HOSTKEY ? "hostkey" : "unknown")); 1484 1485 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 1486 SSH_FP_DEFAULT)) == NULL) 1487 fatal_f("sshkey_fingerprint failed"); 1488 1489 ret = sshkey_verify(key, signature, signaturelen, data, datalen, 1490 sigalg, ssh->compat, &sig_details); 1491 debug3_f("%s %s signature using %s %s%s%s", auth_method, 1492 sshkey_type(key), sigalg == NULL ? "default" : sigalg, 1493 (ret == 0) ? "verified" : "unverified", 1494 (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : ""); 1495 1496 if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) { 1497 req_presence = (options.pubkey_auth_options & 1498 PUBKEYAUTH_TOUCH_REQUIRED) || 1499 !key_opts->no_require_user_presence; 1500 if (req_presence && 1501 (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) { 1502 error("public key %s %s signature for %s%s from %.128s " 1503 "port %d rejected: user presence " 1504 "(authenticator touch) requirement not met ", 1505 sshkey_type(key), fp, 1506 authctxt->valid ? "" : "invalid user ", 1507 authctxt->user, ssh_remote_ipaddr(ssh), 1508 ssh_remote_port(ssh)); 1509 ret = SSH_ERR_SIGNATURE_INVALID; 1510 } 1511 req_verify = (options.pubkey_auth_options & 1512 PUBKEYAUTH_VERIFY_REQUIRED) || key_opts->require_verify; 1513 if (req_verify && 1514 (sig_details->sk_flags & SSH_SK_USER_VERIFICATION_REQD) == 0) { 1515 error("public key %s %s signature for %s%s from %.128s " 1516 "port %d rejected: user verification requirement " 1517 "not met ", sshkey_type(key), fp, 1518 authctxt->valid ? "" : "invalid user ", 1519 authctxt->user, ssh_remote_ipaddr(ssh), 1520 ssh_remote_port(ssh)); 1521 ret = SSH_ERR_SIGNATURE_INVALID; 1522 } 1523 } 1524 auth2_record_key(authctxt, ret == 0, key); 1525 1526 if (key_blobtype == MM_USERKEY) 1527 auth_activate_options(ssh, key_opts); 1528 monitor_reset_key_state(); 1529 1530 sshbuf_reset(m); 1531 1532 /* encode ret != 0 as positive integer, since we're sending u32 */ 1533 encoded_ret = (ret != 0); 1534 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 || 1535 (r = sshbuf_put_u8(m, sig_details != NULL)) != 0) 1536 fatal_fr(r, "assemble"); 1537 if (sig_details != NULL) { 1538 if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 || 1539 (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0) 1540 fatal_fr(r, "assemble sk"); 1541 } 1542 sshkey_sig_details_free(sig_details); 1543 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1544 1545 free(sigalg); 1546 free(fp); 1547 sshkey_free(key); 1548 1549 return ret == 0; 1550 } 1551 1552 static void 1553 mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw) 1554 { 1555 socklen_t fromlen; 1556 struct sockaddr_storage from; 1557 1558 /* 1559 * Get IP address of client. If the connection is not a socket, let 1560 * the address be 0.0.0.0. 1561 */ 1562 memset(&from, 0, sizeof(from)); 1563 fromlen = sizeof(from); 1564 if (ssh_packet_connection_is_on_socket(ssh)) { 1565 if (getpeername(ssh_packet_get_connection_in(ssh), 1566 (struct sockaddr *)&from, &fromlen) == -1) { 1567 debug("getpeername: %.100s", strerror(errno)); 1568 cleanup_exit(254); 1569 } 1570 } 1571 /* Record that there was a login on that tty from the remote host. */ 1572 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1573 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1574 (struct sockaddr *)&from, fromlen); 1575 } 1576 1577 static void 1578 mm_session_close(Session *s) 1579 { 1580 debug3_f("session %d pid %ld", s->self, (long)s->pid); 1581 if (s->ttyfd != -1) { 1582 debug3_f("tty %s ptyfd %d", s->tty, s->ptyfd); 1583 session_pty_cleanup2(s); 1584 } 1585 session_unused(s->self); 1586 } 1587 1588 int 1589 mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m) 1590 { 1591 extern struct monitor *pmonitor; 1592 Session *s; 1593 int r, res, fd0; 1594 1595 debug3_f("entering"); 1596 1597 sshbuf_reset(m); 1598 s = session_new(); 1599 if (s == NULL) 1600 goto error; 1601 s->authctxt = authctxt; 1602 s->pw = authctxt->pw; 1603 s->pid = pmonitor->m_pid; 1604 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1605 if (res == 0) 1606 goto error; 1607 pty_setowner(authctxt->pw, s->tty); 1608 1609 if ((r = sshbuf_put_u32(m, 1)) != 0 || 1610 (r = sshbuf_put_cstring(m, s->tty)) != 0) 1611 fatal_fr(r, "assemble"); 1612 1613 /* We need to trick ttyslot */ 1614 if (dup2(s->ttyfd, 0) == -1) 1615 fatal_f("dup2"); 1616 1617 mm_record_login(ssh, s, authctxt->pw); 1618 1619 /* Now we can close the file descriptor again */ 1620 close(0); 1621 1622 /* send messages generated by record_login */ 1623 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0) 1624 fatal_fr(r, "assemble loginmsg"); 1625 sshbuf_reset(loginmsg); 1626 1627 mm_request_send(sock, MONITOR_ANS_PTY, m); 1628 1629 if (mm_send_fd(sock, s->ptyfd) == -1 || 1630 mm_send_fd(sock, s->ttyfd) == -1) 1631 fatal_f("send fds failed"); 1632 1633 /* make sure nothing uses fd 0 */ 1634 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1635 fatal_f("open(/dev/null): %s", strerror(errno)); 1636 if (fd0 != 0) 1637 error_f("fd0 %d != 0", fd0); 1638 1639 /* slave side of pty is not needed */ 1640 close(s->ttyfd); 1641 s->ttyfd = s->ptyfd; 1642 /* no need to dup() because nobody closes ptyfd */ 1643 s->ptymaster = s->ptyfd; 1644 1645 debug3_f("tty %s ptyfd %d", s->tty, s->ttyfd); 1646 1647 return (0); 1648 1649 error: 1650 if (s != NULL) 1651 mm_session_close(s); 1652 if ((r = sshbuf_put_u32(m, 0)) != 0) 1653 fatal_fr(r, "assemble 0"); 1654 mm_request_send(sock, MONITOR_ANS_PTY, m); 1655 return (0); 1656 } 1657 1658 int 1659 mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m) 1660 { 1661 Session *s; 1662 char *tty; 1663 int r; 1664 1665 debug3_f("entering"); 1666 1667 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0) 1668 fatal_fr(r, "parse tty"); 1669 if ((s = session_by_tty(tty)) != NULL) 1670 mm_session_close(s); 1671 sshbuf_reset(m); 1672 free(tty); 1673 return (0); 1674 } 1675 1676 #ifdef KRB5 1677 int 1678 mm_answer_krb5(struct ssh *ssh, int xsocket, struct sshbuf *m) 1679 { 1680 krb5_data tkt, reply; 1681 char *client_user; 1682 unsigned char *data; 1683 size_t len; 1684 int r; 1685 int success; 1686 1687 /* use temporary var to avoid size issues on 64bit arch */ 1688 if ((r = sshbuf_get_string(m, &data, &len)) != 0) 1689 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1690 tkt.data = data; 1691 tkt.length = len; 1692 1693 success = options.kerberos_authentication && 1694 authctxt->valid && 1695 auth_krb5(ssh, &tkt, &client_user, &reply); 1696 1697 if (tkt.length) 1698 free(tkt.data); 1699 1700 sshbuf_reset(m); 1701 sshbuf_put_u32(m, success); 1702 1703 if (success) { 1704 sshbuf_put_cstring(m, client_user); 1705 sshbuf_put_string(m, reply.data, reply.length); 1706 if (client_user) 1707 free(client_user); 1708 if (reply.length) 1709 free(reply.data); 1710 } 1711 mm_request_send(xsocket, MONITOR_ANS_KRB5, m); 1712 1713 auth_method = "kerberos"; 1714 1715 return success; 1716 } 1717 #endif 1718 1719 int 1720 mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req) 1721 { 1722 extern struct monitor *pmonitor; 1723 int res, status; 1724 1725 debug3_f("tearing down sessions"); 1726 1727 /* The child is terminating */ 1728 session_destroy_all(ssh, &mm_session_close); 1729 1730 #ifdef USE_PAM 1731 if (options.use_pam) 1732 sshpam_cleanup(); 1733 #endif 1734 1735 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1736 if (errno != EINTR) 1737 exit(1); 1738 1739 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1740 1741 /* Terminate process */ 1742 exit(res); 1743 } 1744 1745 void 1746 monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor) 1747 { 1748 ssh_clear_newkeys(ssh, MODE_IN); 1749 ssh_clear_newkeys(ssh, MODE_OUT); 1750 sshbuf_free(child_state); 1751 child_state = NULL; 1752 } 1753 1754 void 1755 monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor) 1756 { 1757 struct kex *kex; 1758 int r; 1759 1760 debug3_f("packet_set_state"); 1761 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1762 fatal_fr(r, "packet_set_state"); 1763 sshbuf_free(child_state); 1764 child_state = NULL; 1765 if ((kex = ssh->kex) == NULL) 1766 fatal_f("internal error: ssh->kex == NULL"); 1767 if (session_id2_len != sshbuf_len(ssh->kex->session_id)) { 1768 fatal_f("incorrect session id length %zu (expected %u)", 1769 sshbuf_len(ssh->kex->session_id), session_id2_len); 1770 } 1771 if (memcmp(sshbuf_ptr(ssh->kex->session_id), session_id2, 1772 session_id2_len) != 0) 1773 fatal_f("session ID mismatch"); 1774 /* XXX set callbacks */ 1775 #ifdef WITH_OPENSSL 1776 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server; 1777 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server; 1778 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server; 1779 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server; 1780 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server; 1781 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1782 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1783 kex->kex[KEX_ECDH_SHA2] = kex_gen_server; 1784 #endif 1785 kex->kex[KEX_C25519_SHA256] = kex_gen_server; 1786 kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server; 1787 kex->load_host_public_key=&get_hostkey_public_by_type; 1788 kex->load_host_private_key=&get_hostkey_private_by_type; 1789 kex->host_key_index=&get_hostkey_index; 1790 kex->sign = sshd_hostkey_sign; 1791 } 1792 1793 /* This function requires careful sanity checking */ 1794 1795 void 1796 mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor) 1797 { 1798 debug3_f("Waiting for new keys"); 1799 1800 if ((child_state = sshbuf_new()) == NULL) 1801 fatal_f("sshbuf_new failed"); 1802 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1803 child_state); 1804 debug3_f("GOT new keys"); 1805 } 1806 1807 1808 /* XXX */ 1809 1810 #define FD_CLOSEONEXEC(x) do { \ 1811 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1812 fatal("fcntl(%d, F_SETFD)", x); \ 1813 } while (0) 1814 1815 static void 1816 monitor_openfds(struct monitor *mon, int do_logfds) 1817 { 1818 int pair[2]; 1819 #ifdef SO_ZEROIZE 1820 int on = 1; 1821 #endif 1822 1823 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1824 fatal_f("socketpair: %s", strerror(errno)); 1825 #ifdef SO_ZEROIZE 1826 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1827 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno)); 1828 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1829 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno)); 1830 #endif 1831 FD_CLOSEONEXEC(pair[0]); 1832 FD_CLOSEONEXEC(pair[1]); 1833 mon->m_recvfd = pair[0]; 1834 mon->m_sendfd = pair[1]; 1835 1836 if (do_logfds) { 1837 if (pipe(pair) == -1) 1838 fatal_f("pipe: %s", strerror(errno)); 1839 FD_CLOSEONEXEC(pair[0]); 1840 FD_CLOSEONEXEC(pair[1]); 1841 mon->m_log_recvfd = pair[0]; 1842 mon->m_log_sendfd = pair[1]; 1843 } else 1844 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1845 } 1846 1847 #define MM_MEMSIZE 65536 1848 1849 struct monitor * 1850 monitor_init(void) 1851 { 1852 struct monitor *mon; 1853 1854 mon = xcalloc(1, sizeof(*mon)); 1855 monitor_openfds(mon, 1); 1856 1857 return mon; 1858 } 1859 1860 void 1861 monitor_reinit(struct monitor *mon) 1862 { 1863 monitor_openfds(mon, 0); 1864 } 1865 1866 #ifdef GSSAPI 1867 int 1868 mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1869 { 1870 gss_OID_desc goid; 1871 OM_uint32 major; 1872 size_t len; 1873 u_char *p; 1874 int r; 1875 1876 if (!options.gss_authentication) 1877 fatal_f("GSSAPI authentication not enabled"); 1878 1879 if ((r = sshbuf_get_string(m, &p, &len)) != 0) 1880 fatal_fr(r, "parse"); 1881 goid.elements = p; 1882 goid.length = len; 1883 1884 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1885 1886 free(goid.elements); 1887 1888 sshbuf_reset(m); 1889 if ((r = sshbuf_put_u32(m, major)) != 0) 1890 fatal_fr(r, "assemble"); 1891 1892 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1893 1894 /* Now we have a context, enable the step */ 1895 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1896 1897 return (0); 1898 } 1899 1900 int 1901 mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1902 { 1903 gss_buffer_desc in; 1904 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1905 OM_uint32 major, minor; 1906 OM_uint32 flags = 0; /* GSI needs this */ 1907 int r; 1908 1909 if (!options.gss_authentication) 1910 fatal_f("GSSAPI authentication not enabled"); 1911 1912 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0) 1913 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1914 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1915 free(in.value); 1916 1917 sshbuf_reset(m); 1918 if ((r = sshbuf_put_u32(m, major)) != 0 || 1919 (r = sshbuf_put_string(m, out.value, out.length)) != 0 || 1920 (r = sshbuf_put_u32(m, flags)) != 0) 1921 fatal_fr(r, "assemble"); 1922 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1923 1924 gss_release_buffer(&minor, &out); 1925 1926 if (major == GSS_S_COMPLETE) { 1927 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1928 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1929 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1930 } 1931 return (0); 1932 } 1933 1934 int 1935 mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m) 1936 { 1937 gss_buffer_desc gssbuf, mic; 1938 OM_uint32 ret; 1939 int r; 1940 1941 if (!options.gss_authentication) 1942 fatal_f("GSSAPI authentication not enabled"); 1943 1944 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 || 1945 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0) 1946 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1947 1948 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1949 1950 free(gssbuf.value); 1951 free(mic.value); 1952 1953 sshbuf_reset(m); 1954 if ((r = sshbuf_put_u32(m, ret)) != 0) 1955 fatal_fr(r, "assemble"); 1956 1957 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1958 1959 if (!GSS_ERROR(ret)) 1960 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1961 1962 return (0); 1963 } 1964 1965 int 1966 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m) 1967 { 1968 int r, authenticated; 1969 const char *displayname; 1970 1971 if (!options.gss_authentication) 1972 fatal_f("GSSAPI authentication not enabled"); 1973 1974 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1975 1976 sshbuf_reset(m); 1977 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 1978 fatal_fr(r, "assemble"); 1979 1980 debug3_f("sending result %d", authenticated); 1981 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1982 1983 auth_method = "gssapi-with-mic"; 1984 1985 if ((displayname = ssh_gssapi_displayname()) != NULL) 1986 auth2_record_info(authctxt, "%s", displayname); 1987 1988 /* Monitor loop will terminate if authenticated */ 1989 return (authenticated); 1990 } 1991 #endif /* GSSAPI */ 1992 1993