1 /* $NetBSD: monitor.c,v 1.46 2024/09/24 21:32:18 christos Exp $ */ 2 /* $OpenBSD: monitor.c,v 1.244 2024/09/15 01:09:40 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 1.46 2024/09/24 21:32:18 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 #include "srclimit.h" 90 91 #include "pfilter.h" 92 93 #ifdef GSSAPI 94 static Gssctxt *gsscontext = NULL; 95 #endif 96 97 /* Imports */ 98 extern ServerOptions options; 99 extern u_int utmp_len; 100 extern struct sshbuf *loginmsg; 101 extern struct sshauthopt *auth_opts; /* XXX move to permanent ssh->authctxt? */ 102 103 /* State exported from the child */ 104 static struct sshbuf *child_state; 105 106 /* Functions on the monitor that answer unprivileged requests */ 107 108 int mm_answer_moduli(struct ssh *, int, struct sshbuf *); 109 int mm_answer_sign(struct ssh *, int, struct sshbuf *); 110 int mm_answer_pwnamallow(struct ssh *, int, struct sshbuf *); 111 int mm_answer_auth2_read_banner(struct ssh *, int, struct sshbuf *); 112 int mm_answer_authserv(struct ssh *, int, struct sshbuf *); 113 int mm_answer_authpassword(struct ssh *, int, struct sshbuf *); 114 int mm_answer_bsdauthquery(struct ssh *, int, struct sshbuf *); 115 int mm_answer_bsdauthrespond(struct ssh *, int, struct sshbuf *); 116 int mm_answer_keyallowed(struct ssh *, int, struct sshbuf *); 117 int mm_answer_keyverify(struct ssh *, int, struct sshbuf *); 118 int mm_answer_pty(struct ssh *, int, struct sshbuf *); 119 int mm_answer_pty_cleanup(struct ssh *, int, struct sshbuf *); 120 int mm_answer_term(struct ssh *, int, struct sshbuf *); 121 122 #ifdef USE_PAM 123 int mm_answer_pam_start(struct ssh *, int, struct sshbuf *); 124 int mm_answer_pam_account(struct ssh *, int, struct sshbuf *); 125 int mm_answer_pam_init_ctx(struct ssh *, int, struct sshbuf *); 126 int mm_answer_pam_query(struct ssh *, int, struct sshbuf *); 127 int mm_answer_pam_respond(struct ssh *, int, struct sshbuf *); 128 int mm_answer_pam_free_ctx(struct ssh *, int, struct sshbuf *); 129 #endif 130 131 #ifdef KRB5 132 int mm_answer_krb5(struct ssh *, int, struct sshbuf *); 133 #endif 134 135 #ifdef GSSAPI 136 int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *); 137 int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *); 138 int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *); 139 int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *); 140 #endif 141 142 static Authctxt *authctxt; 143 144 /* local state for key verify */ 145 static u_char *key_blob = NULL; 146 static size_t key_bloblen = 0; 147 static u_int key_blobtype = MM_NOKEY; 148 static struct sshauthopt *key_opts = NULL; 149 static char *hostbased_cuser = NULL; 150 static char *hostbased_chost = NULL; 151 static const char *auth_method = "unknown"; 152 static const char *auth_submethod = NULL; 153 static u_int session_id2_len = 0; 154 static u_char *session_id2 = NULL; 155 static pid_t monitor_child_pid; 156 int auth_attempted = 0; 157 158 struct mon_table { 159 enum monitor_reqtype type; 160 int flags; 161 int (*f)(struct ssh *, int, struct sshbuf *); 162 }; 163 164 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 165 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 166 #define MON_ONCE 0x0010 /* Disable after calling */ 167 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 168 169 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 170 171 #define MON_PERMIT 0x1000 /* Request is permitted */ 172 173 static int monitor_read(struct ssh *, struct monitor *, struct mon_table *, 174 struct mon_table **); 175 static int monitor_read_log(struct monitor *); 176 177 struct mon_table mon_dispatch_proto20[] = { 178 #ifdef WITH_OPENSSL 179 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 180 #endif 181 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 182 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 183 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 184 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 185 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 186 #ifdef USE_PAM 187 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 188 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 189 {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx}, 190 {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query}, 191 {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond}, 192 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 193 #endif 194 #ifdef BSD_AUTH 195 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 196 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 197 #endif 198 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 199 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 200 #ifdef KRB5 201 {MONITOR_REQ_KRB5, MON_ONCE|MON_AUTH, mm_answer_krb5}, 202 #endif 203 #ifdef GSSAPI 204 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 205 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx}, 206 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok}, 207 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic}, 208 #endif 209 {0, 0, NULL} 210 }; 211 212 struct mon_table mon_dispatch_postauth20[] = { 213 #ifdef WITH_OPENSSL 214 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 215 #endif 216 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 217 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 218 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 219 {MONITOR_REQ_TERM, 0, mm_answer_term}, 220 {0, 0, NULL} 221 }; 222 223 struct mon_table *mon_dispatch; 224 225 /* Specifies if a certain message is allowed at the moment */ 226 static void 227 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 228 { 229 while (ent->f != NULL) { 230 if (ent->type == type) { 231 ent->flags &= ~MON_PERMIT; 232 ent->flags |= permit ? MON_PERMIT : 0; 233 return; 234 } 235 ent++; 236 } 237 } 238 239 static void 240 monitor_permit_authentications(int permit) 241 { 242 struct mon_table *ent = mon_dispatch; 243 244 while (ent->f != NULL) { 245 if (ent->flags & MON_AUTH) { 246 ent->flags &= ~MON_PERMIT; 247 ent->flags |= permit ? MON_PERMIT : 0; 248 } 249 ent++; 250 } 251 } 252 253 void 254 monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor) 255 { 256 struct mon_table *ent; 257 int authenticated = 0, partial = 0; 258 259 debug3("preauth child monitor started"); 260 261 authctxt = (Authctxt *)ssh->authctxt; 262 if (pmonitor->m_recvfd >= 0) 263 close(pmonitor->m_recvfd); 264 if (pmonitor->m_log_sendfd >= 0) 265 close(pmonitor->m_log_sendfd); 266 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 267 268 memset(authctxt, 0, sizeof(*authctxt)); 269 ssh->authctxt = authctxt; 270 271 mon_dispatch = mon_dispatch_proto20; 272 /* Permit requests for moduli and signatures */ 273 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 274 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 275 276 /* The first few requests do not require asynchronous access */ 277 while (!authenticated) { 278 partial = 0; 279 auth_method = "unknown"; 280 auth_submethod = NULL; 281 auth2_authctxt_reset_info(authctxt); 282 283 authenticated = (monitor_read(ssh, pmonitor, 284 mon_dispatch, &ent) == 1); 285 286 /* Record that auth was attempted to set exit status later */ 287 if ((ent->flags & MON_AUTH) != 0) 288 auth_attempted = 1; 289 290 /* Special handling for multiple required authentications */ 291 if (options.num_auth_methods != 0) { 292 if (authenticated && 293 !auth2_update_methods_lists(authctxt, 294 auth_method, auth_submethod)) { 295 debug3_f("method %s: partial", auth_method); 296 authenticated = 0; 297 partial = 1; 298 } 299 } 300 301 if (authenticated) { 302 if (!(ent->flags & MON_AUTHDECIDE)) 303 fatal_f("unexpected authentication from %d", 304 ent->type); 305 if (authctxt->pw->pw_uid == 0 && 306 !auth_root_allowed(ssh, auth_method)) 307 authenticated = 0; 308 #ifdef USE_PAM 309 /* PAM needs to perform account checks after auth */ 310 if (options.use_pam && authenticated) { 311 struct sshbuf *m; 312 313 if ((m = sshbuf_new()) == NULL) 314 fatal("%s: sshbuf_new failed", __func__); 315 316 mm_request_receive_expect(pmonitor->m_sendfd, 317 MONITOR_REQ_PAM_ACCOUNT, m); 318 authenticated = mm_answer_pam_account(ssh, pmonitor->m_sendfd, m); 319 sshbuf_free(m); 320 } 321 #endif 322 } 323 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 324 auth_log(ssh, authenticated, partial, 325 auth_method, auth_submethod); 326 if (!partial && !authenticated) 327 authctxt->failures++; 328 if (authenticated || partial) { 329 auth2_update_session_info(authctxt, 330 auth_method, auth_submethod); 331 } 332 } 333 if (authctxt->failures > options.max_authtries) { 334 pfilter_notify(1); 335 /* Shouldn't happen */ 336 fatal_f("privsep child made too many authentication " 337 "attempts"); 338 } 339 } 340 341 if (!authctxt->valid) { 342 pfilter_notify(1); 343 fatal_f("authenticated invalid user"); 344 } 345 if (strcmp(auth_method, "unknown") == 0) { 346 pfilter_notify(1); 347 fatal_f("authentication method name unknown"); 348 } 349 350 debug_f("user %s authenticated by privileged process", authctxt->user); 351 auth_attempted = 0; 352 ssh->authctxt = NULL; 353 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 354 355 mm_get_keystate(ssh, pmonitor); 356 357 /* Drain any buffered messages from the child */ 358 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 359 ; 360 361 if (pmonitor->m_recvfd >= 0) 362 close(pmonitor->m_recvfd); 363 if (pmonitor->m_log_sendfd >= 0) 364 close(pmonitor->m_log_sendfd); 365 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 366 } 367 368 static void 369 monitor_set_child_handler(pid_t pid) 370 { 371 monitor_child_pid = pid; 372 } 373 374 static void 375 monitor_child_handler(int sig) 376 { 377 kill(monitor_child_pid, sig); 378 } 379 380 void 381 monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor) 382 { 383 close(pmonitor->m_recvfd); 384 pmonitor->m_recvfd = -1; 385 386 monitor_set_child_handler(pmonitor->m_pid); 387 ssh_signal(SIGHUP, &monitor_child_handler); 388 ssh_signal(SIGTERM, &monitor_child_handler); 389 ssh_signal(SIGINT, &monitor_child_handler); 390 391 mon_dispatch = mon_dispatch_postauth20; 392 393 /* Permit requests for moduli and signatures */ 394 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 395 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 396 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 397 398 if (auth_opts->permit_pty_flag) { 399 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 400 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 401 } 402 403 for (;;) 404 monitor_read(ssh, pmonitor, mon_dispatch, NULL); 405 } 406 407 static int 408 monitor_read_log(struct monitor *pmonitor) 409 { 410 struct sshbuf *logmsg; 411 u_int len, level, forced; 412 char *msg; 413 u_char *p; 414 int r; 415 416 if ((logmsg = sshbuf_new()) == NULL) 417 fatal_f("sshbuf_new"); 418 419 /* Read length */ 420 if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0) 421 fatal_fr(r, "reserve len"); 422 if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) { 423 if (errno == EPIPE) { 424 sshbuf_free(logmsg); 425 debug_f("child log fd closed"); 426 close(pmonitor->m_log_recvfd); 427 pmonitor->m_log_recvfd = -1; 428 return -1; 429 } 430 fatal_f("log fd read: %s", strerror(errno)); 431 } 432 if ((r = sshbuf_get_u32(logmsg, &len)) != 0) 433 fatal_fr(r, "parse len"); 434 if (len <= 4 || len > 8192) 435 fatal_f("invalid log message length %u", len); 436 437 /* Read severity, message */ 438 sshbuf_reset(logmsg); 439 if ((r = sshbuf_reserve(logmsg, len, &p)) != 0) 440 fatal_fr(r, "reserve msg"); 441 if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len) 442 fatal_f("log fd read: %s", strerror(errno)); 443 if ((r = sshbuf_get_u32(logmsg, &level)) != 0 || 444 (r = sshbuf_get_u32(logmsg, &forced)) != 0 || 445 (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0) 446 fatal_fr(r, "parse"); 447 448 /* Log it */ 449 if (log_level_name(level) == NULL) 450 fatal_f("invalid log level %u (corrupted message?)", level); 451 sshlogdirect(level, forced, "%s [preauth]", msg); 452 453 sshbuf_free(logmsg); 454 free(msg); 455 456 return 0; 457 } 458 459 static int 460 monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent, 461 struct mon_table **pent) 462 { 463 struct sshbuf *m; 464 int r, ret; 465 u_char type; 466 struct pollfd pfd[2]; 467 468 for (;;) { 469 memset(&pfd, 0, sizeof(pfd)); 470 pfd[0].fd = pmonitor->m_sendfd; 471 pfd[0].events = POLLIN; 472 pfd[1].fd = pmonitor->m_log_recvfd; 473 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 474 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 475 if (errno == EINTR || errno == EAGAIN) 476 continue; 477 fatal_f("poll: %s", strerror(errno)); 478 } 479 if (pfd[1].revents) { 480 /* 481 * Drain all log messages before processing next 482 * monitor request. 483 */ 484 monitor_read_log(pmonitor); 485 continue; 486 } 487 if (pfd[0].revents) 488 break; /* Continues below */ 489 } 490 491 if ((m = sshbuf_new()) == NULL) 492 fatal_f("sshbuf_new"); 493 494 mm_request_receive(pmonitor->m_sendfd, m); 495 if ((r = sshbuf_get_u8(m, &type)) != 0) 496 fatal_fr(r, "parse type"); 497 498 debug3_f("checking request %d", type); 499 500 while (ent->f != NULL) { 501 if (ent->type == type) 502 break; 503 ent++; 504 } 505 506 if (ent->f != NULL) { 507 if (!(ent->flags & MON_PERMIT)) 508 fatal_f("unpermitted request %d", type); 509 ret = (*ent->f)(ssh, pmonitor->m_sendfd, m); 510 sshbuf_free(m); 511 512 /* The child may use this request only once, disable it */ 513 if (ent->flags & MON_ONCE) { 514 debug2_f("%d used once, disabling now", type); 515 ent->flags &= ~MON_PERMIT; 516 } 517 518 if (pent != NULL) 519 *pent = ent; 520 521 return ret; 522 } 523 524 fatal_f("unsupported request: %d", type); 525 526 /* NOTREACHED */ 527 return (-1); 528 } 529 530 /* allowed key state */ 531 static int 532 monitor_allowed_key(const u_char *blob, u_int bloblen) 533 { 534 /* make sure key is allowed */ 535 if (key_blob == NULL || key_bloblen != bloblen || 536 timingsafe_bcmp(key_blob, blob, key_bloblen)) 537 return (0); 538 return (1); 539 } 540 541 static void 542 monitor_reset_key_state(void) 543 { 544 /* reset state */ 545 free(key_blob); 546 free(hostbased_cuser); 547 free(hostbased_chost); 548 sshauthopt_free(key_opts); 549 key_blob = NULL; 550 key_bloblen = 0; 551 key_blobtype = MM_NOKEY; 552 key_opts = NULL; 553 hostbased_cuser = NULL; 554 hostbased_chost = NULL; 555 } 556 557 #ifdef WITH_OPENSSL 558 int 559 mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m) 560 { 561 DH *dh; 562 const BIGNUM *dh_p, *dh_g; 563 int r; 564 u_int min, want, max; 565 566 if ((r = sshbuf_get_u32(m, &min)) != 0 || 567 (r = sshbuf_get_u32(m, &want)) != 0 || 568 (r = sshbuf_get_u32(m, &max)) != 0) 569 fatal_fr(r, "parse"); 570 571 debug3_f("got parameters: %d %d %d", min, want, max); 572 /* We need to check here, too, in case the child got corrupted */ 573 if (max < min || want < min || max < want) 574 fatal_f("bad parameters: %d %d %d", min, want, max); 575 576 sshbuf_reset(m); 577 578 dh = choose_dh(min, want, max); 579 if (dh == NULL) { 580 if ((r = sshbuf_put_u8(m, 0)) != 0) 581 fatal_fr(r, "assemble empty"); 582 return (0); 583 } else { 584 /* Send first bignum */ 585 DH_get0_pqg(dh, &dh_p, NULL, &dh_g); 586 if ((r = sshbuf_put_u8(m, 1)) != 0 || 587 (r = sshbuf_put_bignum2(m, dh_p)) != 0 || 588 (r = sshbuf_put_bignum2(m, dh_g)) != 0) 589 fatal_fr(r, "assemble"); 590 591 DH_free(dh); 592 } 593 mm_request_send(sock, MONITOR_ANS_MODULI, m); 594 return (0); 595 } 596 #endif 597 598 int 599 mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m) 600 { 601 extern int auth_sock; /* XXX move to state struct? */ 602 struct sshkey *key; 603 struct sshbuf *sigbuf = NULL; 604 u_char *p = NULL, *signature = NULL; 605 char *alg = NULL; 606 size_t datlen, siglen, alglen; 607 int r, is_proof = 0; 608 u_int keyid, compat; 609 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 610 611 debug3_f("entering"); 612 613 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 614 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 615 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0 || 616 (r = sshbuf_get_u32(m, &compat)) != 0) 617 fatal_fr(r, "parse"); 618 if (keyid > INT_MAX) 619 fatal_f("invalid key ID"); 620 621 /* 622 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 623 * SHA384 (48 bytes) and SHA512 (64 bytes). 624 * 625 * Otherwise, verify the signature request is for a hostkey 626 * proof. 627 * 628 * XXX perform similar check for KEX signature requests too? 629 * it's not trivial, since what is signed is the hash, rather 630 * than the full kex structure... 631 */ 632 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 633 /* 634 * Construct expected hostkey proof and compare it to what 635 * the client sent us. 636 */ 637 if (session_id2_len == 0) /* hostkeys is never first */ 638 fatal_f("bad data length: %zu", datlen); 639 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 640 fatal_f("no hostkey for index %d", keyid); 641 if ((sigbuf = sshbuf_new()) == NULL) 642 fatal_f("sshbuf_new"); 643 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 644 (r = sshbuf_put_string(sigbuf, session_id2, 645 session_id2_len)) != 0 || 646 (r = sshkey_puts(key, sigbuf)) != 0) 647 fatal_fr(r, "assemble private key proof"); 648 if (datlen != sshbuf_len(sigbuf) || 649 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 650 fatal_f("bad data length: %zu, hostkey proof len %zu", 651 datlen, sshbuf_len(sigbuf)); 652 sshbuf_free(sigbuf); 653 is_proof = 1; 654 } 655 656 /* save session id, it will be passed on the first call */ 657 if (session_id2_len == 0) { 658 session_id2_len = datlen; 659 session_id2 = xmalloc(session_id2_len); 660 memcpy(session_id2, p, session_id2_len); 661 } 662 663 if ((key = get_hostkey_by_index(keyid)) != NULL) { 664 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 665 options.sk_provider, NULL, compat)) != 0) 666 fatal_fr(r, "sign"); 667 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 668 auth_sock > 0) { 669 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 670 p, datlen, alg, compat)) != 0) 671 fatal_fr(r, "agent sign"); 672 } else 673 fatal_f("no hostkey from index %d", keyid); 674 675 debug3_f("%s %s signature len=%zu", alg, 676 is_proof ? "hostkey proof" : "KEX", siglen); 677 678 sshbuf_reset(m); 679 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 680 fatal_fr(r, "assemble"); 681 682 free(alg); 683 free(p); 684 free(signature); 685 686 mm_request_send(sock, MONITOR_ANS_SIGN, m); 687 688 /* Turn on permissions for getpwnam */ 689 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 690 691 return (0); 692 } 693 694 #define PUTPW(b, id) \ 695 do { \ 696 if ((r = sshbuf_put_string(b, \ 697 &pwent->id, sizeof(pwent->id))) != 0) \ 698 fatal_fr(r, "assemble %s", #id); \ 699 } while (0) 700 701 void 702 mm_encode_server_options(struct sshbuf *m) 703 { 704 int r; 705 u_int i; 706 707 /* XXX this leaks raw pointers to the unpriv child processes */ 708 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0) 709 fatal_fr(r, "assemble options"); 710 711 #define M_CP_STROPT(x) do { \ 712 if (options.x != NULL && \ 713 (r = sshbuf_put_cstring(m, options.x)) != 0) \ 714 fatal_fr(r, "assemble %s", #x); \ 715 } while (0) 716 #define M_CP_STRARRAYOPT(x, nx) do { \ 717 for (i = 0; i < options.nx; i++) { \ 718 if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \ 719 fatal_fr(r, "assemble %s", #x); \ 720 } \ 721 } while (0) 722 /* See comment in servconf.h */ 723 COPY_MATCH_STRING_OPTS(); 724 #undef M_CP_STROPT 725 #undef M_CP_STRARRAYOPT 726 } 727 728 /* Retrieves the password entry and also checks if the user is permitted */ 729 int 730 mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m) 731 { 732 struct passwd *pwent; 733 int r, allowed = 0; 734 735 debug3_f("entering"); 736 737 if (authctxt->attempt++ != 0) 738 fatal_f("multiple attempts for getpwnam"); 739 740 if ((r = sshbuf_get_cstring(m, &authctxt->user, NULL)) != 0) 741 fatal_fr(r, "parse"); 742 743 pwent = getpwnamallow(ssh, authctxt->user); 744 745 setproctitle("%s [priv]", pwent ? authctxt->user : "unknown"); 746 747 sshbuf_reset(m); 748 749 if (pwent == NULL) { 750 if ((r = sshbuf_put_u8(m, 0)) != 0) 751 fatal_fr(r, "assemble fakepw"); 752 authctxt->pw = fakepw(); 753 goto out; 754 } 755 756 allowed = 1; 757 authctxt->pw = pwent; 758 authctxt->valid = 1; 759 760 /* XXX send fake class/dir/shell, etc. */ 761 if ((r = sshbuf_put_u8(m, 1)) != 0) 762 fatal_fr(r, "assemble ok"); 763 PUTPW(m, pw_uid); 764 PUTPW(m, pw_gid); 765 PUTPW(m, pw_change); 766 PUTPW(m, pw_expire); 767 if ((r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || 768 (r = sshbuf_put_cstring(m, "*")) != 0 || 769 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 || 770 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 || 771 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 || 772 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0) 773 fatal_fr(r, "assemble pw"); 774 775 out: 776 ssh_packet_set_log_preamble(ssh, "%suser %s", 777 authctxt->valid ? "authenticating" : "invalid ", authctxt->user); 778 779 if (options.refuse_connection) { 780 logit("administratively prohibited connection for " 781 "%s%s from %.128s port %d", 782 authctxt->valid ? "" : "invalid user ", 783 authctxt->user, ssh_remote_ipaddr(ssh), 784 ssh_remote_port(ssh)); 785 cleanup_exit(EXIT_CONFIG_REFUSED); 786 } 787 788 /* Send active options to unpriv */ 789 mm_encode_server_options(m); 790 791 /* Create valid auth method lists */ 792 if (auth2_setup_methods_lists(authctxt) != 0) { 793 /* 794 * The monitor will continue long enough to let the child 795 * run to its packet_disconnect(), but it must not allow any 796 * authentication to succeed. 797 */ 798 debug_f("no valid authentication method lists"); 799 } 800 801 debug3_f("sending MONITOR_ANS_PWNAM: %d", allowed); 802 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 803 804 /* Allow service/style information on the auth context */ 805 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 806 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 807 808 #ifdef USE_PAM 809 if (options.use_pam) 810 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); 811 #endif 812 813 return (0); 814 } 815 816 int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m) 817 { 818 char *banner; 819 int r; 820 821 sshbuf_reset(m); 822 banner = auth2_read_banner(); 823 if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0) 824 fatal_fr(r, "assemble"); 825 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 826 free(banner); 827 828 return (0); 829 } 830 831 int 832 mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m) 833 { 834 int r; 835 836 monitor_permit_authentications(1); 837 838 if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 || 839 (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0) 840 fatal_fr(r, "parse"); 841 debug3_f("service=%s, style=%s", authctxt->service, authctxt->style); 842 843 if (strlen(authctxt->style) == 0) { 844 free(authctxt->style); 845 authctxt->style = NULL; 846 } 847 848 return (0); 849 } 850 851 int 852 mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m) 853 { 854 static int call_count; 855 char *passwd; 856 int r, authenticated; 857 size_t plen; 858 859 if (!options.password_authentication) 860 fatal_f("password authentication not enabled"); 861 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0) 862 fatal_fr(r, "parse"); 863 /* Only authenticate if the context is valid */ 864 authenticated = options.password_authentication && 865 auth_password(ssh, passwd); 866 freezero(passwd, plen); 867 868 sshbuf_reset(m); 869 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 870 fatal_fr(r, "assemble"); 871 #ifdef USE_PAM 872 if ((r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0) 873 fatal_fr(r, "assemble PAM"); 874 #endif 875 debug3_f("sending result %d", authenticated); 876 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 877 878 call_count++; 879 if (plen == 0 && call_count == 1) 880 auth_method = "none"; 881 else 882 auth_method = "password"; 883 884 /* Causes monitor loop to terminate if authenticated */ 885 return (authenticated); 886 } 887 888 #ifdef BSD_AUTH 889 int 890 mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m) 891 { 892 char *name, *infotxt; 893 u_int numprompts, *echo_on, success; 894 char **prompts; 895 int r; 896 897 if (!options.kbd_interactive_authentication) 898 fatal_f("kbd-int authentication not enabled"); 899 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 900 &prompts, &echo_on) < 0 ? 0 : 1; 901 902 sshbuf_reset(m); 903 if ((r = sshbuf_put_u32(m, success)) != 0) 904 fatal_fr(r, "assemble"); 905 if (success) { 906 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0) 907 fatal_fr(r, "assemble prompt"); 908 } 909 910 debug3_f("sending challenge success: %u", success); 911 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 912 913 if (success) { 914 free(name); 915 free(infotxt); 916 free(prompts); 917 free(echo_on); 918 } 919 920 return (0); 921 } 922 923 int 924 mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m) 925 { 926 char *response; 927 int r, authok; 928 929 if (!options.kbd_interactive_authentication) 930 fatal_f("kbd-int authentication not enabled"); 931 if (authctxt->as == NULL) 932 fatal_f("no bsd auth session"); 933 934 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 935 fatal_fr(r, "parse"); 936 authok = options.kbd_interactive_authentication && 937 auth_userresponse(authctxt->as, response, 0); 938 authctxt->as = NULL; 939 debug3_f("<%s> = <%d>", response, authok); 940 free(response); 941 942 sshbuf_reset(m); 943 if ((r = sshbuf_put_u32(m, authok)) != 0) 944 fatal_fr(r, "assemble"); 945 946 debug3_f("sending authenticated: %d", authok); 947 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 948 949 auth_method = "keyboard-interactive"; 950 auth_submethod = "bsdauth"; 951 952 return (authok != 0); 953 } 954 #endif 955 956 #ifdef SKEY 957 int 958 mm_answer_skeyquery(int sock, struct sshbuf *m) 959 { 960 struct skey skey; 961 char challenge[1024]; 962 u_int success; 963 964 success = skeychallenge(&skey, authctxt->user, challenge, 965 sizeof(challenge)) < 0 ? 0 : 1; 966 967 sshbuf_reset(m); 968 sshbuf_put_int(m, success); 969 if (success) 970 sshbuf_put_cstring(m, challenge); 971 972 debug3("%s: sending challenge success: %u", __func__, success); 973 mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m); 974 975 return (0); 976 } 977 978 int 979 mm_answer_skeyrespond(int sock, struct sshbuf *m) 980 { 981 char *response; 982 int authok; 983 int r; 984 985 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 986 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 987 988 authok = (options.kbd_interactive_authentication && 989 authctxt->valid && 990 skey_haskey(authctxt->pw->pw_name) == 0 && 991 skey_passcheck(authctxt->pw->pw_name, response) != -1); 992 993 free(response); 994 995 sshbuf_reset(m); 996 sshbuf_put_int(m, authok); 997 998 debug3("%s: sending authenticated: %d", __func__, authok); 999 mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m); 1000 1001 auth_method = "skey"; 1002 auth_submethod = "bsdauth"; 1003 1004 return (authok != 0); 1005 } 1006 #endif 1007 1008 #ifdef USE_PAM 1009 int 1010 mm_answer_pam_start(struct ssh *ssh, int sock, struct sshbuf *m) 1011 { 1012 if (!options.use_pam) 1013 fatal("UsePAM not set, but ended up in %s anyway", __func__); 1014 1015 start_pam(ssh); 1016 1017 if (options.kbd_interactive_authentication) 1018 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); 1019 1020 return (0); 1021 } 1022 1023 int 1024 mm_answer_pam_account(struct ssh *ssh, int sock, struct sshbuf *m) 1025 { 1026 u_int ret; 1027 int r; 1028 1029 if (!options.use_pam) 1030 fatal("UsePAM not set, but ended up in %s anyway", __func__); 1031 1032 ret = do_pam_account(); 1033 1034 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1035 (r = sshbuf_put_stringb(m, loginmsg)) != 0) 1036 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1037 1038 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m); 1039 1040 return (ret); 1041 } 1042 1043 static void *sshpam_ctxt, *sshpam_authok; 1044 extern KbdintDevice sshpam_device; 1045 1046 int 1047 mm_answer_pam_init_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1048 { 1049 u_int ok = 0; 1050 int r; 1051 1052 debug3("%s", __func__); 1053 if (!options.kbd_interactive_authentication) 1054 fatal("%s: kbd-int authentication not enabled", __func__); 1055 if (sshpam_ctxt != NULL) 1056 fatal("%s: already called", __func__); 1057 sshpam_ctxt = (sshpam_device.init_ctx)(ssh->authctxt); 1058 sshpam_authok = NULL; 1059 sshbuf_reset(m); 1060 if (sshpam_ctxt != NULL) { 1061 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 1062 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_QUERY, 1); 1063 ok = 1; 1064 } 1065 if ((r = sshbuf_put_u32(m, ok)) != 0) 1066 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1067 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); 1068 return (0); 1069 } 1070 1071 int 1072 mm_answer_pam_query(struct ssh *ssh, int sock, struct sshbuf *m) 1073 { 1074 char *name, *info, **prompts; 1075 u_int i, num, *echo_on; 1076 int r, ret; 1077 1078 debug3("%s", __func__); 1079 sshpam_authok = NULL; 1080 if (sshpam_ctxt == NULL) 1081 fatal("%s: no context", __func__); 1082 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, 1083 &num, &prompts, &echo_on); 1084 if (ret == 0 && num == 0) 1085 sshpam_authok = sshpam_ctxt; 1086 if (num > 1 || name == NULL || info == NULL) 1087 fatal("sshpam_device.query failed"); 1088 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_RESPOND, 1); 1089 sshbuf_reset(m); 1090 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1091 (r = sshbuf_put_cstring(m, name)) != 0 || 1092 (r = sshbuf_put_cstring(m, info)) != 0 || 1093 (r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0 || 1094 (r = sshbuf_put_u32(m, num)) != 0) 1095 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1096 free(name); 1097 free(info); 1098 for (i = 0; i < num; ++i) { 1099 if ((r = sshbuf_put_cstring(m, prompts[i])) != 0 || 1100 (r = sshbuf_put_u32(m, echo_on[i])) != 0) 1101 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1102 free(prompts[i]); 1103 } 1104 free(prompts); 1105 free(echo_on); 1106 auth_method = "keyboard-interactive/pam"; 1107 auth_submethod = "pam"; 1108 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m); 1109 return (0); 1110 } 1111 1112 int 1113 mm_answer_pam_respond(struct ssh *ssh, int sock, struct sshbuf *m) 1114 { 1115 char **resp; 1116 u_int i, num; 1117 int r, ret; 1118 1119 debug3("%s", __func__); 1120 if (sshpam_ctxt == NULL) 1121 fatal("%s: no context", __func__); 1122 sshpam_authok = NULL; 1123 if ((r = sshbuf_get_u32(m, &num)) != 0) 1124 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1125 if (num > PAM_MAX_NUM_MSG) { 1126 fatal_f("Too many PAM messages, got %u, expected <= %u", 1127 num, (unsigned)PAM_MAX_NUM_MSG); 1128 } 1129 if (num > 0) { 1130 resp = xmalloc(num * sizeof(char *)); 1131 for (i = 0; i < num; ++i) 1132 if ((r = sshbuf_get_cstring(m, &resp[i], NULL)) != 0) 1133 fatal("%s: buffer error: %s", __func__, 1134 ssh_err(r)); 1135 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp); 1136 for (i = 0; i < num; ++i) 1137 free(resp[i]); 1138 free(resp); 1139 } else { 1140 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL); 1141 } 1142 sshbuf_reset(m); 1143 if ((r = sshbuf_put_u32(m, ret)) != 0) 1144 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1145 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m); 1146 auth_method = "keyboard-interactive/pam"; 1147 auth_submethod = "pam"; 1148 if (ret == 0) 1149 sshpam_authok = sshpam_ctxt; 1150 return (0); 1151 } 1152 1153 int 1154 mm_answer_pam_free_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1155 { 1156 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt; 1157 1158 debug3("%s", __func__); 1159 if (sshpam_ctxt == NULL) 1160 fatal("%s: no context", __func__); 1161 (sshpam_device.free_ctx)(sshpam_ctxt); 1162 sshpam_ctxt = sshpam_authok = NULL; 1163 sshbuf_reset(m); 1164 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); 1165 /* Allow another attempt */ 1166 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 1167 auth_method = "keyboard-interactive/pam"; 1168 auth_submethod = "pam"; 1169 return r; 1170 } 1171 #endif 1172 1173 /* 1174 * Check that the key type appears in the supplied pattern list, ignoring 1175 * mismatches in the signature algorithm. (Signature algorithm checks are 1176 * performed in the unprivileged authentication code). 1177 * Returns 1 on success, 0 otherwise. 1178 */ 1179 static int 1180 key_base_type_match(const char *method, const struct sshkey *key, 1181 const char *list) 1182 { 1183 char *s, *l, *ol = xstrdup(list); 1184 int found = 0; 1185 1186 l = ol; 1187 for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) { 1188 if (sshkey_type_from_name(s) == key->type) { 1189 found = 1; 1190 break; 1191 } 1192 } 1193 if (!found) { 1194 error("%s key type %s is not in permitted list %s", method, 1195 sshkey_ssh_name(key), list); 1196 } 1197 1198 free(ol); 1199 return found; 1200 } 1201 1202 int 1203 mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m) 1204 { 1205 struct sshkey *key = NULL; 1206 char *cuser, *chost; 1207 u_int pubkey_auth_attempt; 1208 u_int type = 0; 1209 int r, allowed = 0; 1210 struct sshauthopt *opts = NULL; 1211 1212 debug3_f("entering"); 1213 if ((r = sshbuf_get_u32(m, &type)) != 0 || 1214 (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 || 1215 (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 || 1216 (r = sshkey_froms(m, &key)) != 0 || 1217 (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0) 1218 fatal_fr(r, "parse"); 1219 1220 if (key != NULL && authctxt->valid) { 1221 switch (type) { 1222 case MM_USERKEY: 1223 auth_method = "publickey"; 1224 if (!options.pubkey_authentication) 1225 break; 1226 if (auth2_key_already_used(authctxt, key)) 1227 break; 1228 if (!key_base_type_match(auth_method, key, 1229 options.pubkey_accepted_algos)) 1230 break; 1231 allowed = user_key_allowed(ssh, authctxt->pw, key, 1232 pubkey_auth_attempt, &opts); 1233 break; 1234 case MM_HOSTKEY: 1235 auth_method = "hostbased"; 1236 if (!options.hostbased_authentication) 1237 break; 1238 if (auth2_key_already_used(authctxt, key)) 1239 break; 1240 if (!key_base_type_match(auth_method, key, 1241 options.hostbased_accepted_algos)) 1242 break; 1243 allowed = hostbased_key_allowed(ssh, authctxt->pw, 1244 cuser, chost, key); 1245 auth2_record_info(authctxt, 1246 "client user \"%.100s\", client host \"%.100s\"", 1247 cuser, chost); 1248 break; 1249 default: 1250 fatal_f("unknown key type %u", type); 1251 break; 1252 } 1253 } 1254 1255 debug3_f("%s authentication%s: %s key is %s", auth_method, 1256 pubkey_auth_attempt ? "" : " test", 1257 (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key), 1258 allowed ? "allowed" : "not allowed"); 1259 1260 auth2_record_key(authctxt, 0, key); 1261 1262 /* clear temporarily storage (used by verify) */ 1263 monitor_reset_key_state(); 1264 1265 if (allowed) { 1266 /* Save temporarily for comparison in verify */ 1267 if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0) 1268 fatal_fr(r, "sshkey_to_blob"); 1269 key_blobtype = type; 1270 key_opts = opts; 1271 hostbased_cuser = cuser; 1272 hostbased_chost = chost; 1273 } else { 1274 /* Log failed attempt */ 1275 auth_log(ssh, 0, 0, auth_method, NULL); 1276 pfilter_notify(1); 1277 free(cuser); 1278 free(chost); 1279 } 1280 sshkey_free(key); 1281 1282 sshbuf_reset(m); 1283 if ((r = sshbuf_put_u32(m, allowed)) != 0) 1284 fatal_fr(r, "assemble"); 1285 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0) 1286 fatal_fr(r, "sshauthopt_serialise"); 1287 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 1288 1289 if (!allowed) 1290 sshauthopt_free(opts); 1291 1292 return (0); 1293 } 1294 1295 static int 1296 monitor_valid_userblob(struct ssh *ssh, const u_char *data, u_int datalen) 1297 { 1298 struct sshbuf *b; 1299 struct sshkey *hostkey = NULL; 1300 const u_char *p; 1301 char *userstyle, *cp; 1302 size_t len; 1303 u_char type; 1304 int hostbound = 0, r, fail = 0; 1305 1306 if ((b = sshbuf_from(data, datalen)) == NULL) 1307 fatal_f("sshbuf_from"); 1308 1309 if (ssh->compat & SSH_OLD_SESSIONID) { 1310 p = sshbuf_ptr(b); 1311 len = sshbuf_len(b); 1312 if ((session_id2 == NULL) || 1313 (len < session_id2_len) || 1314 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1315 fail++; 1316 if ((r = sshbuf_consume(b, session_id2_len)) != 0) 1317 fatal_fr(r, "consume"); 1318 } else { 1319 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1320 fatal_fr(r, "parse sessionid"); 1321 if ((session_id2 == NULL) || 1322 (len != session_id2_len) || 1323 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1324 fail++; 1325 } 1326 if ((r = sshbuf_get_u8(b, &type)) != 0) 1327 fatal_fr(r, "parse type"); 1328 if (type != SSH2_MSG_USERAUTH_REQUEST) 1329 fail++; 1330 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1331 fatal_fr(r, "parse userstyle"); 1332 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1333 authctxt->style ? ":" : "", 1334 authctxt->style ? authctxt->style : ""); 1335 if (strcmp(userstyle, cp) != 0) { 1336 logit("wrong user name passed to monitor: " 1337 "expected %s != %.100s", userstyle, cp); 1338 fail++; 1339 } 1340 free(userstyle); 1341 free(cp); 1342 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1343 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1344 fatal_fr(r, "parse method"); 1345 if (strcmp("publickey", cp) != 0) { 1346 if (strcmp("publickey-hostbound-v00@openssh.com", cp) == 0) 1347 hostbound = 1; 1348 else 1349 fail++; 1350 } 1351 free(cp); 1352 if ((r = sshbuf_get_u8(b, &type)) != 0) 1353 fatal_fr(r, "parse pktype"); 1354 if (type == 0) 1355 fail++; 1356 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1357 (r = sshbuf_skip_string(b)) != 0 || /* pkblob */ 1358 (hostbound && (r = sshkey_froms(b, &hostkey)) != 0)) 1359 fatal_fr(r, "parse pk"); 1360 if (sshbuf_len(b) != 0) 1361 fail++; 1362 sshbuf_free(b); 1363 if (hostkey != NULL) { 1364 /* 1365 * Ensure this is actually one of our hostkeys; unfortunately 1366 * can't check ssh->kex->initial_hostkey directly at this point 1367 * as packet state has not yet been exported to monitor. 1368 */ 1369 if (get_hostkey_index(hostkey, 1, ssh) == -1) 1370 fatal_f("hostbound hostkey does not match"); 1371 sshkey_free(hostkey); 1372 } 1373 return (fail == 0); 1374 } 1375 1376 static int 1377 monitor_valid_hostbasedblob(struct ssh *ssh, const u_char *data, u_int datalen, 1378 const char *cuser, const char *chost) 1379 { 1380 struct sshbuf *b; 1381 const u_char *p; 1382 char *cp, *userstyle; 1383 size_t len; 1384 int r, fail = 0; 1385 u_char type; 1386 1387 if ((b = sshbuf_from(data, datalen)) == NULL) 1388 fatal_f("sshbuf_new"); 1389 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1390 fatal_fr(r, "parse sessionid"); 1391 1392 if ((session_id2 == NULL) || 1393 (len != session_id2_len) || 1394 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1395 fail++; 1396 1397 if ((r = sshbuf_get_u8(b, &type)) != 0) 1398 fatal_fr(r, "parse type"); 1399 if (type != SSH2_MSG_USERAUTH_REQUEST) 1400 fail++; 1401 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1402 fatal_fr(r, "parse userstyle"); 1403 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1404 authctxt->style ? ":" : "", 1405 authctxt->style ? authctxt->style : ""); 1406 if (strcmp(userstyle, cp) != 0) { 1407 logit("wrong user name passed to monitor: " 1408 "expected %s != %.100s", userstyle, cp); 1409 fail++; 1410 } 1411 free(userstyle); 1412 free(cp); 1413 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1414 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1415 fatal_fr(r, "parse method"); 1416 if (strcmp(cp, "hostbased") != 0) 1417 fail++; 1418 free(cp); 1419 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1420 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1421 fatal_fr(r, "parse pk"); 1422 1423 /* verify client host, strip trailing dot if necessary */ 1424 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1425 fatal_fr(r, "parse host"); 1426 if (((len = strlen(cp)) > 0) && cp[len - 1] == '.') 1427 cp[len - 1] = '\0'; 1428 if (strcmp(cp, chost) != 0) 1429 fail++; 1430 free(cp); 1431 1432 /* verify client user */ 1433 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1434 fatal_fr(r, "parse ruser"); 1435 if (strcmp(cp, cuser) != 0) 1436 fail++; 1437 free(cp); 1438 1439 if (sshbuf_len(b) != 0) 1440 fail++; 1441 sshbuf_free(b); 1442 return (fail == 0); 1443 } 1444 1445 int 1446 mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m) 1447 { 1448 struct sshkey *key; 1449 const u_char *signature, *data, *blob; 1450 char *sigalg = NULL, *fp = NULL; 1451 size_t signaturelen, datalen, bloblen; 1452 int r, ret, req_presence = 0, req_verify = 0, valid_data = 0; 1453 int encoded_ret; 1454 struct sshkey_sig_details *sig_details = NULL; 1455 1456 if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 || 1457 (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 || 1458 (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 || 1459 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0) 1460 fatal_fr(r, "parse"); 1461 1462 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1463 !monitor_allowed_key(blob, bloblen)) 1464 fatal_f("bad key, not previously allowed"); 1465 1466 /* Empty signature algorithm means NULL. */ 1467 if (*sigalg == '\0') { 1468 free(sigalg); 1469 sigalg = NULL; 1470 } 1471 1472 /* XXX use sshkey_froms here; need to change key_blob, etc. */ 1473 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0) 1474 fatal_fr(r, "parse key"); 1475 1476 switch (key_blobtype) { 1477 case MM_USERKEY: 1478 valid_data = monitor_valid_userblob(ssh, data, datalen); 1479 auth_method = "publickey"; 1480 break; 1481 case MM_HOSTKEY: 1482 valid_data = monitor_valid_hostbasedblob(ssh, data, datalen, 1483 hostbased_cuser, hostbased_chost); 1484 auth_method = "hostbased"; 1485 break; 1486 default: 1487 valid_data = 0; 1488 break; 1489 } 1490 if (!valid_data) 1491 fatal_f("bad %s signature data blob", 1492 key_blobtype == MM_USERKEY ? "userkey" : 1493 (key_blobtype == MM_HOSTKEY ? "hostkey" : "unknown")); 1494 1495 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 1496 SSH_FP_DEFAULT)) == NULL) 1497 fatal_f("sshkey_fingerprint failed"); 1498 1499 ret = sshkey_verify(key, signature, signaturelen, data, datalen, 1500 sigalg, ssh->compat, &sig_details); 1501 debug3_f("%s %s signature using %s %s%s%s", auth_method, 1502 sshkey_type(key), sigalg == NULL ? "default" : sigalg, 1503 (ret == 0) ? "verified" : "unverified", 1504 (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : ""); 1505 1506 if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) { 1507 req_presence = (options.pubkey_auth_options & 1508 PUBKEYAUTH_TOUCH_REQUIRED) || 1509 !key_opts->no_require_user_presence; 1510 if (req_presence && 1511 (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) { 1512 error("public key %s %s signature for %s%s from %.128s " 1513 "port %d rejected: user presence " 1514 "(authenticator touch) requirement not met ", 1515 sshkey_type(key), fp, 1516 authctxt->valid ? "" : "invalid user ", 1517 authctxt->user, ssh_remote_ipaddr(ssh), 1518 ssh_remote_port(ssh)); 1519 ret = SSH_ERR_SIGNATURE_INVALID; 1520 } 1521 req_verify = (options.pubkey_auth_options & 1522 PUBKEYAUTH_VERIFY_REQUIRED) || key_opts->require_verify; 1523 if (req_verify && 1524 (sig_details->sk_flags & SSH_SK_USER_VERIFICATION_REQD) == 0) { 1525 error("public key %s %s signature for %s%s from %.128s " 1526 "port %d rejected: user verification requirement " 1527 "not met ", sshkey_type(key), fp, 1528 authctxt->valid ? "" : "invalid user ", 1529 authctxt->user, ssh_remote_ipaddr(ssh), 1530 ssh_remote_port(ssh)); 1531 ret = SSH_ERR_SIGNATURE_INVALID; 1532 } 1533 } 1534 auth2_record_key(authctxt, ret == 0, key); 1535 1536 if (key_blobtype == MM_USERKEY && ret == 0) 1537 auth_activate_options(ssh, key_opts); 1538 monitor_reset_key_state(); 1539 1540 sshbuf_reset(m); 1541 1542 /* encode ret != 0 as positive integer, since we're sending u32 */ 1543 encoded_ret = (ret != 0); 1544 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 || 1545 (r = sshbuf_put_u8(m, sig_details != NULL)) != 0) 1546 fatal_fr(r, "assemble"); 1547 if (sig_details != NULL) { 1548 if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 || 1549 (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0) 1550 fatal_fr(r, "assemble sk"); 1551 } 1552 sshkey_sig_details_free(sig_details); 1553 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1554 1555 free(sigalg); 1556 free(fp); 1557 sshkey_free(key); 1558 1559 return ret == 0; 1560 } 1561 1562 static void 1563 mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw) 1564 { 1565 socklen_t fromlen; 1566 struct sockaddr_storage from; 1567 1568 /* 1569 * Get IP address of client. If the connection is not a socket, let 1570 * the address be 0.0.0.0. 1571 */ 1572 memset(&from, 0, sizeof(from)); 1573 fromlen = sizeof(from); 1574 if (ssh_packet_connection_is_on_socket(ssh)) { 1575 if (getpeername(ssh_packet_get_connection_in(ssh), 1576 (struct sockaddr *)&from, &fromlen) == -1) { 1577 debug("getpeername: %.100s", strerror(errno)); 1578 cleanup_exit(254); 1579 } 1580 } 1581 /* Record that there was a login on that tty from the remote host. */ 1582 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1583 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1584 (struct sockaddr *)&from, fromlen); 1585 } 1586 1587 static void 1588 mm_session_close(Session *s) 1589 { 1590 debug3_f("session %d pid %ld", s->self, (long)s->pid); 1591 if (s->ttyfd != -1) { 1592 debug3_f("tty %s ptyfd %d", s->tty, s->ptyfd); 1593 session_pty_cleanup2(s); 1594 } 1595 session_unused(s->self); 1596 } 1597 1598 int 1599 mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m) 1600 { 1601 extern struct monitor *pmonitor; 1602 Session *s; 1603 int r, res, fd0; 1604 1605 debug3_f("entering"); 1606 1607 sshbuf_reset(m); 1608 s = session_new(); 1609 if (s == NULL) 1610 goto error; 1611 s->authctxt = authctxt; 1612 s->pw = authctxt->pw; 1613 s->pid = pmonitor->m_pid; 1614 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1615 if (res == 0) 1616 goto error; 1617 pty_setowner(authctxt->pw, s->tty); 1618 1619 if ((r = sshbuf_put_u32(m, 1)) != 0 || 1620 (r = sshbuf_put_cstring(m, s->tty)) != 0) 1621 fatal_fr(r, "assemble"); 1622 1623 /* We need to trick ttyslot */ 1624 if (dup2(s->ttyfd, 0) == -1) 1625 fatal_f("dup2"); 1626 1627 mm_record_login(ssh, s, authctxt->pw); 1628 1629 /* Now we can close the file descriptor again */ 1630 close(0); 1631 1632 /* send messages generated by record_login */ 1633 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0) 1634 fatal_fr(r, "assemble loginmsg"); 1635 sshbuf_reset(loginmsg); 1636 1637 mm_request_send(sock, MONITOR_ANS_PTY, m); 1638 1639 if (mm_send_fd(sock, s->ptyfd) == -1 || 1640 mm_send_fd(sock, s->ttyfd) == -1) 1641 fatal_f("send fds failed"); 1642 1643 /* make sure nothing uses fd 0 */ 1644 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1645 fatal_f("open(/dev/null): %s", strerror(errno)); 1646 if (fd0 != 0) 1647 error_f("fd0 %d != 0", fd0); 1648 1649 /* slave side of pty is not needed */ 1650 close(s->ttyfd); 1651 s->ttyfd = s->ptyfd; 1652 /* no need to dup() because nobody closes ptyfd */ 1653 s->ptymaster = s->ptyfd; 1654 1655 debug3_f("tty %s ptyfd %d", s->tty, s->ttyfd); 1656 1657 return (0); 1658 1659 error: 1660 if (s != NULL) 1661 mm_session_close(s); 1662 if ((r = sshbuf_put_u32(m, 0)) != 0) 1663 fatal_fr(r, "assemble 0"); 1664 mm_request_send(sock, MONITOR_ANS_PTY, m); 1665 return (0); 1666 } 1667 1668 int 1669 mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m) 1670 { 1671 Session *s; 1672 char *tty; 1673 int r; 1674 1675 debug3_f("entering"); 1676 1677 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0) 1678 fatal_fr(r, "parse tty"); 1679 if ((s = session_by_tty(tty)) != NULL) 1680 mm_session_close(s); 1681 sshbuf_reset(m); 1682 free(tty); 1683 return (0); 1684 } 1685 1686 #ifdef KRB5 1687 int 1688 mm_answer_krb5(struct ssh *ssh, int xsocket, struct sshbuf *m) 1689 { 1690 krb5_data tkt, reply; 1691 char *client_user; 1692 unsigned char *data; 1693 size_t len; 1694 int r; 1695 int success; 1696 1697 /* use temporary var to avoid size issues on 64bit arch */ 1698 if ((r = sshbuf_get_string(m, &data, &len)) != 0) 1699 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1700 tkt.data = data; 1701 tkt.length = len; 1702 1703 success = options.kerberos_authentication && 1704 authctxt->valid && 1705 auth_krb5(ssh, &tkt, &client_user, &reply); 1706 1707 if (tkt.length) 1708 free(tkt.data); 1709 1710 sshbuf_reset(m); 1711 sshbuf_put_u32(m, success); 1712 1713 if (success) { 1714 sshbuf_put_cstring(m, client_user); 1715 sshbuf_put_string(m, reply.data, reply.length); 1716 if (client_user) 1717 free(client_user); 1718 if (reply.length) 1719 free(reply.data); 1720 } 1721 mm_request_send(xsocket, MONITOR_ANS_KRB5, m); 1722 1723 auth_method = "kerberos"; 1724 1725 return success; 1726 } 1727 #endif 1728 1729 int 1730 mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req) 1731 { 1732 extern struct monitor *pmonitor; 1733 int res, status; 1734 1735 debug3_f("tearing down sessions"); 1736 1737 /* The child is terminating */ 1738 session_destroy_all(ssh, &mm_session_close); 1739 1740 #ifdef USE_PAM 1741 if (options.use_pam) 1742 sshpam_cleanup(); 1743 #endif 1744 1745 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1746 if (errno != EINTR) 1747 exit(1); 1748 1749 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1750 1751 /* Terminate process */ 1752 exit(res); 1753 } 1754 1755 void 1756 monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor) 1757 { 1758 ssh_clear_newkeys(ssh, MODE_IN); 1759 ssh_clear_newkeys(ssh, MODE_OUT); 1760 sshbuf_free(child_state); 1761 child_state = NULL; 1762 } 1763 1764 void 1765 monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor) 1766 { 1767 struct kex *kex; 1768 int r; 1769 1770 debug3_f("packet_set_state"); 1771 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1772 fatal_fr(r, "packet_set_state"); 1773 sshbuf_free(child_state); 1774 child_state = NULL; 1775 if ((kex = ssh->kex) == NULL) 1776 fatal_f("internal error: ssh->kex == NULL"); 1777 if (session_id2_len != sshbuf_len(ssh->kex->session_id)) { 1778 fatal_f("incorrect session id length %zu (expected %u)", 1779 sshbuf_len(ssh->kex->session_id), session_id2_len); 1780 } 1781 if (memcmp(sshbuf_ptr(ssh->kex->session_id), session_id2, 1782 session_id2_len) != 0) 1783 fatal_f("session ID mismatch"); 1784 /* XXX set callbacks */ 1785 #ifdef WITH_OPENSSL 1786 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server; 1787 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server; 1788 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server; 1789 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server; 1790 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server; 1791 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1792 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1793 kex->kex[KEX_ECDH_SHA2] = kex_gen_server; 1794 #endif 1795 kex->kex[KEX_C25519_SHA256] = kex_gen_server; 1796 kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server; 1797 kex->kex[KEX_KEM_MLKEM768X25519_SHA256] = kex_gen_server; 1798 kex->load_host_public_key=&get_hostkey_public_by_type; 1799 kex->load_host_private_key=&get_hostkey_private_by_type; 1800 kex->host_key_index=&get_hostkey_index; 1801 kex->sign = sshd_hostkey_sign; 1802 } 1803 1804 /* This function requires careful sanity checking */ 1805 1806 void 1807 mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor) 1808 { 1809 debug3_f("Waiting for new keys"); 1810 1811 if ((child_state = sshbuf_new()) == NULL) 1812 fatal_f("sshbuf_new failed"); 1813 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1814 child_state); 1815 debug3_f("GOT new keys"); 1816 } 1817 1818 1819 /* XXX */ 1820 1821 #define FD_CLOSEONEXEC(x) do { \ 1822 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1823 fatal("fcntl(%d, F_SETFD)", x); \ 1824 } while (0) 1825 1826 static void 1827 monitor_openfds(struct monitor *mon, int do_logfds) 1828 { 1829 int pair[2]; 1830 #ifdef SO_ZEROIZE 1831 int on = 1; 1832 #endif 1833 1834 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1835 fatal_f("socketpair: %s", strerror(errno)); 1836 #ifdef SO_ZEROIZE 1837 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1838 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno)); 1839 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1840 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno)); 1841 #endif 1842 FD_CLOSEONEXEC(pair[0]); 1843 FD_CLOSEONEXEC(pair[1]); 1844 mon->m_recvfd = pair[0]; 1845 mon->m_sendfd = pair[1]; 1846 1847 if (do_logfds) { 1848 if (pipe(pair) == -1) 1849 fatal_f("pipe: %s", strerror(errno)); 1850 FD_CLOSEONEXEC(pair[0]); 1851 FD_CLOSEONEXEC(pair[1]); 1852 mon->m_log_recvfd = pair[0]; 1853 mon->m_log_sendfd = pair[1]; 1854 } else 1855 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1856 } 1857 1858 #define MM_MEMSIZE 65536 1859 1860 struct monitor * 1861 monitor_init(void) 1862 { 1863 struct monitor *mon; 1864 1865 mon = xcalloc(1, sizeof(*mon)); 1866 monitor_openfds(mon, 1); 1867 1868 return mon; 1869 } 1870 1871 void 1872 monitor_reinit(struct monitor *mon) 1873 { 1874 monitor_openfds(mon, 0); 1875 } 1876 1877 #ifdef GSSAPI 1878 int 1879 mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1880 { 1881 gss_OID_desc goid; 1882 OM_uint32 major; 1883 size_t len; 1884 u_char *p; 1885 int r; 1886 1887 if (!options.gss_authentication) 1888 fatal_f("GSSAPI authentication not enabled"); 1889 1890 if ((r = sshbuf_get_string(m, &p, &len)) != 0) 1891 fatal_fr(r, "parse"); 1892 goid.elements = p; 1893 goid.length = len; 1894 1895 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1896 1897 free(goid.elements); 1898 1899 sshbuf_reset(m); 1900 if ((r = sshbuf_put_u32(m, major)) != 0) 1901 fatal_fr(r, "assemble"); 1902 1903 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1904 1905 /* Now we have a context, enable the step */ 1906 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1907 1908 return (0); 1909 } 1910 1911 int 1912 mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1913 { 1914 gss_buffer_desc in; 1915 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1916 OM_uint32 major, minor; 1917 OM_uint32 flags = 0; /* GSI needs this */ 1918 int r; 1919 1920 if (!options.gss_authentication) 1921 fatal_f("GSSAPI authentication not enabled"); 1922 1923 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0) 1924 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1925 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1926 free(in.value); 1927 1928 sshbuf_reset(m); 1929 if ((r = sshbuf_put_u32(m, major)) != 0 || 1930 (r = sshbuf_put_string(m, out.value, out.length)) != 0 || 1931 (r = sshbuf_put_u32(m, flags)) != 0) 1932 fatal_fr(r, "assemble"); 1933 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1934 1935 gss_release_buffer(&minor, &out); 1936 1937 if (major == GSS_S_COMPLETE) { 1938 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1939 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1940 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1941 } 1942 return (0); 1943 } 1944 1945 int 1946 mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m) 1947 { 1948 gss_buffer_desc gssbuf, mic; 1949 OM_uint32 ret; 1950 int r; 1951 1952 if (!options.gss_authentication) 1953 fatal_f("GSSAPI authentication not enabled"); 1954 1955 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 || 1956 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0) 1957 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1958 1959 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1960 1961 free(gssbuf.value); 1962 free(mic.value); 1963 1964 sshbuf_reset(m); 1965 if ((r = sshbuf_put_u32(m, ret)) != 0) 1966 fatal_fr(r, "assemble"); 1967 1968 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1969 1970 if (!GSS_ERROR(ret)) 1971 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1972 1973 return (0); 1974 } 1975 1976 int 1977 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m) 1978 { 1979 int r, authenticated; 1980 const char *displayname; 1981 1982 if (!options.gss_authentication) 1983 fatal_f("GSSAPI authentication not enabled"); 1984 1985 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1986 1987 sshbuf_reset(m); 1988 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 1989 fatal_fr(r, "assemble"); 1990 1991 debug3_f("sending result %d", authenticated); 1992 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1993 1994 auth_method = "gssapi-with-mic"; 1995 1996 if ((displayname = ssh_gssapi_displayname()) != NULL) 1997 auth2_record_info(authctxt, "%s", displayname); 1998 1999 /* Monitor loop will terminate if authenticated */ 2000 return (authenticated); 2001 } 2002 #endif /* GSSAPI */ 2003 2004