1 /* $OpenBSD: monitor.c,v 1.210 2020/03/13 03:17:07 djm Exp $ */ 2 /* 3 * Copyright 2002 Niels Provos <provos@citi.umich.edu> 4 * Copyright 2002 Markus Friedl <markus@openbsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include "includes.h" 29 30 #include <sys/types.h> 31 #include <sys/socket.h> 32 #include <sys/wait.h> 33 34 #include <errno.h> 35 #include <fcntl.h> 36 #include <limits.h> 37 #ifdef HAVE_PATHS_H 38 #include <paths.h> 39 #endif 40 #include <pwd.h> 41 #include <signal.h> 42 #ifdef HAVE_STDINT_H 43 # include <stdint.h> 44 #endif 45 #include <stdlib.h> 46 #include <string.h> 47 #include <stdarg.h> 48 #include <stdio.h> 49 #include <unistd.h> 50 #ifdef HAVE_POLL_H 51 #include <poll.h> 52 #else 53 # ifdef HAVE_SYS_POLL_H 54 # include <sys/poll.h> 55 # endif 56 #endif 57 58 #ifdef WITH_OPENSSL 59 #include <openssl/dh.h> 60 #endif 61 62 #include "openbsd-compat/sys-tree.h" 63 #include "openbsd-compat/sys-queue.h" 64 #include "openbsd-compat/openssl-compat.h" 65 66 #include "atomicio.h" 67 #include "xmalloc.h" 68 #include "ssh.h" 69 #include "sshkey.h" 70 #include "sshbuf.h" 71 #include "hostfile.h" 72 #include "auth.h" 73 #include "cipher.h" 74 #include "kex.h" 75 #include "dh.h" 76 #include "auth-pam.h" 77 #include "packet.h" 78 #include "auth-options.h" 79 #include "sshpty.h" 80 #include "channels.h" 81 #include "session.h" 82 #include "sshlogin.h" 83 #include "canohost.h" 84 #include "log.h" 85 #include "misc.h" 86 #include "servconf.h" 87 #include "monitor.h" 88 #ifdef GSSAPI 89 #include "ssh-gss.h" 90 #endif 91 #include "monitor_wrap.h" 92 #include "monitor_fdpass.h" 93 #include "compat.h" 94 #include "ssh2.h" 95 #include "authfd.h" 96 #include "match.h" 97 #include "ssherr.h" 98 #include "sk-api.h" 99 100 #ifdef GSSAPI 101 static Gssctxt *gsscontext = NULL; 102 #endif 103 104 /* Imports */ 105 extern ServerOptions options; 106 extern u_int utmp_len; 107 extern u_char session_id[]; 108 extern struct sshbuf *loginmsg; 109 extern struct sshauthopt *auth_opts; /* XXX move to permanent ssh->authctxt? */ 110 111 /* State exported from the child */ 112 static struct sshbuf *child_state; 113 114 /* Functions on the monitor that answer unprivileged requests */ 115 116 int mm_answer_moduli(struct ssh *, int, struct sshbuf *); 117 int mm_answer_sign(struct ssh *, int, struct sshbuf *); 118 int mm_answer_pwnamallow(struct ssh *, int, struct sshbuf *); 119 int mm_answer_auth2_read_banner(struct ssh *, int, struct sshbuf *); 120 int mm_answer_authserv(struct ssh *, int, struct sshbuf *); 121 int mm_answer_authpassword(struct ssh *, int, struct sshbuf *); 122 int mm_answer_bsdauthquery(struct ssh *, int, struct sshbuf *); 123 int mm_answer_bsdauthrespond(struct ssh *, int, struct sshbuf *); 124 int mm_answer_skeyquery(struct ssh *, int, struct sshbuf *); 125 int mm_answer_skeyrespond(struct ssh *, int, struct sshbuf *); 126 int mm_answer_keyallowed(struct ssh *, int, struct sshbuf *); 127 int mm_answer_keyverify(struct ssh *, int, struct sshbuf *); 128 int mm_answer_pty(struct ssh *, int, struct sshbuf *); 129 int mm_answer_pty_cleanup(struct ssh *, int, struct sshbuf *); 130 int mm_answer_term(struct ssh *, int, struct sshbuf *); 131 int mm_answer_rsa_keyallowed(struct ssh *, int, struct sshbuf *); 132 int mm_answer_rsa_challenge(struct ssh *, int, struct sshbuf *); 133 int mm_answer_rsa_response(struct ssh *, int, struct sshbuf *); 134 int mm_answer_sesskey(struct ssh *, int, struct sshbuf *); 135 int mm_answer_sessid(struct ssh *, int, struct sshbuf *); 136 137 #ifdef USE_PAM 138 int mm_answer_pam_start(struct ssh *, int, struct sshbuf *); 139 int mm_answer_pam_account(struct ssh *, int, struct sshbuf *); 140 int mm_answer_pam_init_ctx(struct ssh *, int, struct sshbuf *); 141 int mm_answer_pam_query(struct ssh *, int, struct sshbuf *); 142 int mm_answer_pam_respond(struct ssh *, int, struct sshbuf *); 143 int mm_answer_pam_free_ctx(struct ssh *, int, struct sshbuf *); 144 #endif 145 146 #ifdef GSSAPI 147 int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *); 148 int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *); 149 int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *); 150 int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *); 151 #endif 152 153 #ifdef SSH_AUDIT_EVENTS 154 int mm_answer_audit_event(struct ssh *, int, struct sshbuf *); 155 int mm_answer_audit_command(struct ssh *, int, struct sshbuf *); 156 #endif 157 158 static Authctxt *authctxt; 159 160 /* local state for key verify */ 161 static u_char *key_blob = NULL; 162 static size_t key_bloblen = 0; 163 static int key_blobtype = MM_NOKEY; 164 static struct sshauthopt *key_opts = NULL; 165 static char *hostbased_cuser = NULL; 166 static char *hostbased_chost = NULL; 167 static char *auth_method = "unknown"; 168 static char *auth_submethod = NULL; 169 static u_int session_id2_len = 0; 170 static u_char *session_id2 = NULL; 171 static pid_t monitor_child_pid; 172 173 struct mon_table { 174 enum monitor_reqtype type; 175 int flags; 176 int (*f)(struct ssh *, int, struct sshbuf *); 177 }; 178 179 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 180 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 181 #define MON_ONCE 0x0010 /* Disable after calling */ 182 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 183 184 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 185 186 #define MON_PERMIT 0x1000 /* Request is permitted */ 187 188 static int monitor_read(struct ssh *, struct monitor *, struct mon_table *, 189 struct mon_table **); 190 static int monitor_read_log(struct monitor *); 191 192 struct mon_table mon_dispatch_proto20[] = { 193 #ifdef WITH_OPENSSL 194 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 195 #endif 196 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 197 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 198 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 199 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 200 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 201 #ifdef USE_PAM 202 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 203 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 204 {MONITOR_REQ_PAM_INIT_CTX, MON_ONCE, mm_answer_pam_init_ctx}, 205 {MONITOR_REQ_PAM_QUERY, 0, mm_answer_pam_query}, 206 {MONITOR_REQ_PAM_RESPOND, MON_ONCE, mm_answer_pam_respond}, 207 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 208 #endif 209 #ifdef SSH_AUDIT_EVENTS 210 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 211 #endif 212 #ifdef BSD_AUTH 213 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 214 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 215 #endif 216 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 217 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 218 #ifdef GSSAPI 219 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 220 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx}, 221 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok}, 222 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic}, 223 #endif 224 {0, 0, NULL} 225 }; 226 227 struct mon_table mon_dispatch_postauth20[] = { 228 #ifdef WITH_OPENSSL 229 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 230 #endif 231 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 232 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 233 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 234 {MONITOR_REQ_TERM, 0, mm_answer_term}, 235 #ifdef SSH_AUDIT_EVENTS 236 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 237 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command}, 238 #endif 239 {0, 0, NULL} 240 }; 241 242 struct mon_table *mon_dispatch; 243 244 /* Specifies if a certain message is allowed at the moment */ 245 static void 246 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 247 { 248 while (ent->f != NULL) { 249 if (ent->type == type) { 250 ent->flags &= ~MON_PERMIT; 251 ent->flags |= permit ? MON_PERMIT : 0; 252 return; 253 } 254 ent++; 255 } 256 } 257 258 static void 259 monitor_permit_authentications(int permit) 260 { 261 struct mon_table *ent = mon_dispatch; 262 263 while (ent->f != NULL) { 264 if (ent->flags & MON_AUTH) { 265 ent->flags &= ~MON_PERMIT; 266 ent->flags |= permit ? MON_PERMIT : 0; 267 } 268 ent++; 269 } 270 } 271 272 void 273 monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor) 274 { 275 struct mon_table *ent; 276 int authenticated = 0, partial = 0; 277 278 debug3("preauth child monitor started"); 279 280 if (pmonitor->m_recvfd >= 0) 281 close(pmonitor->m_recvfd); 282 if (pmonitor->m_log_sendfd >= 0) 283 close(pmonitor->m_log_sendfd); 284 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 285 286 authctxt = (Authctxt *)ssh->authctxt; 287 memset(authctxt, 0, sizeof(*authctxt)); 288 ssh->authctxt = authctxt; 289 290 authctxt->loginmsg = loginmsg; 291 292 mon_dispatch = mon_dispatch_proto20; 293 /* Permit requests for moduli and signatures */ 294 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 295 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 296 297 /* The first few requests do not require asynchronous access */ 298 while (!authenticated) { 299 partial = 0; 300 auth_method = "unknown"; 301 auth_submethod = NULL; 302 auth2_authctxt_reset_info(authctxt); 303 304 authenticated = (monitor_read(ssh, pmonitor, 305 mon_dispatch, &ent) == 1); 306 307 /* Special handling for multiple required authentications */ 308 if (options.num_auth_methods != 0) { 309 if (authenticated && 310 !auth2_update_methods_lists(authctxt, 311 auth_method, auth_submethod)) { 312 debug3("%s: method %s: partial", __func__, 313 auth_method); 314 authenticated = 0; 315 partial = 1; 316 } 317 } 318 319 if (authenticated) { 320 if (!(ent->flags & MON_AUTHDECIDE)) 321 fatal("%s: unexpected authentication from %d", 322 __func__, ent->type); 323 if (authctxt->pw->pw_uid == 0 && 324 !auth_root_allowed(ssh, auth_method)) 325 authenticated = 0; 326 #ifdef USE_PAM 327 /* PAM needs to perform account checks after auth */ 328 if (options.use_pam && authenticated) { 329 struct sshbuf *m; 330 331 if ((m = sshbuf_new()) == NULL) 332 fatal("%s: sshbuf_new failed", 333 __func__); 334 mm_request_receive_expect(pmonitor->m_sendfd, 335 MONITOR_REQ_PAM_ACCOUNT, m); 336 authenticated = mm_answer_pam_account( 337 ssh, pmonitor->m_sendfd, m); 338 sshbuf_free(m); 339 } 340 #endif 341 } 342 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 343 auth_log(ssh, authenticated, partial, 344 auth_method, auth_submethod); 345 if (!partial && !authenticated) 346 authctxt->failures++; 347 if (authenticated || partial) { 348 auth2_update_session_info(authctxt, 349 auth_method, auth_submethod); 350 } 351 } 352 } 353 354 if (!authctxt->valid) 355 fatal("%s: authenticated invalid user", __func__); 356 if (strcmp(auth_method, "unknown") == 0) 357 fatal("%s: authentication method name unknown", __func__); 358 359 debug("%s: %s has been authenticated by privileged process", 360 __func__, authctxt->user); 361 ssh->authctxt = NULL; 362 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 363 364 mm_get_keystate(ssh, pmonitor); 365 366 /* Drain any buffered messages from the child */ 367 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 368 ; 369 370 if (pmonitor->m_recvfd >= 0) 371 close(pmonitor->m_recvfd); 372 if (pmonitor->m_log_sendfd >= 0) 373 close(pmonitor->m_log_sendfd); 374 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 375 } 376 377 static void 378 monitor_set_child_handler(pid_t pid) 379 { 380 monitor_child_pid = pid; 381 } 382 383 static void 384 monitor_child_handler(int sig) 385 { 386 kill(monitor_child_pid, sig); 387 } 388 389 void 390 monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor) 391 { 392 close(pmonitor->m_recvfd); 393 pmonitor->m_recvfd = -1; 394 395 monitor_set_child_handler(pmonitor->m_pid); 396 ssh_signal(SIGHUP, &monitor_child_handler); 397 ssh_signal(SIGTERM, &monitor_child_handler); 398 ssh_signal(SIGINT, &monitor_child_handler); 399 #ifdef SIGXFSZ 400 ssh_signal(SIGXFSZ, SIG_IGN); 401 #endif 402 403 mon_dispatch = mon_dispatch_postauth20; 404 405 /* Permit requests for moduli and signatures */ 406 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 407 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 408 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 409 410 if (auth_opts->permit_pty_flag) { 411 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 412 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 413 } 414 415 for (;;) 416 monitor_read(ssh, pmonitor, mon_dispatch, NULL); 417 } 418 419 static int 420 monitor_read_log(struct monitor *pmonitor) 421 { 422 struct sshbuf *logmsg; 423 u_int len, level; 424 char *msg; 425 u_char *p; 426 int r; 427 428 if ((logmsg = sshbuf_new()) == NULL) 429 fatal("%s: sshbuf_new", __func__); 430 431 /* Read length */ 432 if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0) 433 fatal("%s: reserve: %s", __func__, ssh_err(r)); 434 if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) { 435 if (errno == EPIPE) { 436 sshbuf_free(logmsg); 437 debug("%s: child log fd closed", __func__); 438 close(pmonitor->m_log_recvfd); 439 pmonitor->m_log_recvfd = -1; 440 return -1; 441 } 442 fatal("%s: log fd read: %s", __func__, strerror(errno)); 443 } 444 if ((r = sshbuf_get_u32(logmsg, &len)) != 0) 445 fatal("%s: get len: %s", __func__, ssh_err(r)); 446 if (len <= 4 || len > 8192) 447 fatal("%s: invalid log message length %u", __func__, len); 448 449 /* Read severity, message */ 450 sshbuf_reset(logmsg); 451 if ((r = sshbuf_reserve(logmsg, len, &p)) != 0) 452 fatal("%s: reserve: %s", __func__, ssh_err(r)); 453 if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len) 454 fatal("%s: log fd read: %s", __func__, strerror(errno)); 455 if ((r = sshbuf_get_u32(logmsg, &level)) != 0 || 456 (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0) 457 fatal("%s: decode: %s", __func__, ssh_err(r)); 458 459 /* Log it */ 460 if (log_level_name(level) == NULL) 461 fatal("%s: invalid log level %u (corrupted message?)", 462 __func__, level); 463 do_log2(level, "%s [preauth]", msg); 464 465 sshbuf_free(logmsg); 466 free(msg); 467 468 return 0; 469 } 470 471 static int 472 monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent, 473 struct mon_table **pent) 474 { 475 struct sshbuf *m; 476 int r, ret; 477 u_char type; 478 struct pollfd pfd[2]; 479 480 for (;;) { 481 memset(&pfd, 0, sizeof(pfd)); 482 pfd[0].fd = pmonitor->m_sendfd; 483 pfd[0].events = POLLIN; 484 pfd[1].fd = pmonitor->m_log_recvfd; 485 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 486 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 487 if (errno == EINTR || errno == EAGAIN) 488 continue; 489 fatal("%s: poll: %s", __func__, strerror(errno)); 490 } 491 if (pfd[1].revents) { 492 /* 493 * Drain all log messages before processing next 494 * monitor request. 495 */ 496 monitor_read_log(pmonitor); 497 continue; 498 } 499 if (pfd[0].revents) 500 break; /* Continues below */ 501 } 502 503 if ((m = sshbuf_new()) == NULL) 504 fatal("%s: sshbuf_new", __func__); 505 506 mm_request_receive(pmonitor->m_sendfd, m); 507 if ((r = sshbuf_get_u8(m, &type)) != 0) 508 fatal("%s: decode: %s", __func__, ssh_err(r)); 509 510 debug3("%s: checking request %d", __func__, type); 511 512 while (ent->f != NULL) { 513 if (ent->type == type) 514 break; 515 ent++; 516 } 517 518 if (ent->f != NULL) { 519 if (!(ent->flags & MON_PERMIT)) 520 fatal("%s: unpermitted request %d", __func__, 521 type); 522 ret = (*ent->f)(ssh, pmonitor->m_sendfd, m); 523 sshbuf_free(m); 524 525 /* The child may use this request only once, disable it */ 526 if (ent->flags & MON_ONCE) { 527 debug2("%s: %d used once, disabling now", __func__, 528 type); 529 ent->flags &= ~MON_PERMIT; 530 } 531 532 if (pent != NULL) 533 *pent = ent; 534 535 return ret; 536 } 537 538 fatal("%s: unsupported request: %d", __func__, type); 539 540 /* NOTREACHED */ 541 return (-1); 542 } 543 544 /* allowed key state */ 545 static int 546 monitor_allowed_key(const u_char *blob, u_int bloblen) 547 { 548 /* make sure key is allowed */ 549 if (key_blob == NULL || key_bloblen != bloblen || 550 timingsafe_bcmp(key_blob, blob, key_bloblen)) 551 return (0); 552 return (1); 553 } 554 555 static void 556 monitor_reset_key_state(void) 557 { 558 /* reset state */ 559 free(key_blob); 560 free(hostbased_cuser); 561 free(hostbased_chost); 562 sshauthopt_free(key_opts); 563 key_blob = NULL; 564 key_bloblen = 0; 565 key_blobtype = MM_NOKEY; 566 key_opts = NULL; 567 hostbased_cuser = NULL; 568 hostbased_chost = NULL; 569 } 570 571 #ifdef WITH_OPENSSL 572 int 573 mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m) 574 { 575 DH *dh; 576 const BIGNUM *dh_p, *dh_g; 577 int r; 578 u_int min, want, max; 579 580 if ((r = sshbuf_get_u32(m, &min)) != 0 || 581 (r = sshbuf_get_u32(m, &want)) != 0 || 582 (r = sshbuf_get_u32(m, &max)) != 0) 583 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 584 585 debug3("%s: got parameters: %d %d %d", 586 __func__, min, want, max); 587 /* We need to check here, too, in case the child got corrupted */ 588 if (max < min || want < min || max < want) 589 fatal("%s: bad parameters: %d %d %d", 590 __func__, min, want, max); 591 592 sshbuf_reset(m); 593 594 dh = choose_dh(min, want, max); 595 if (dh == NULL) { 596 if ((r = sshbuf_put_u8(m, 0)) != 0) 597 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 598 return (0); 599 } else { 600 /* Send first bignum */ 601 DH_get0_pqg(dh, &dh_p, NULL, &dh_g); 602 if ((r = sshbuf_put_u8(m, 1)) != 0 || 603 (r = sshbuf_put_bignum2(m, dh_p)) != 0 || 604 (r = sshbuf_put_bignum2(m, dh_g)) != 0) 605 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 606 607 DH_free(dh); 608 } 609 mm_request_send(sock, MONITOR_ANS_MODULI, m); 610 return (0); 611 } 612 #endif 613 614 int 615 mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m) 616 { 617 extern int auth_sock; /* XXX move to state struct? */ 618 struct sshkey *key; 619 struct sshbuf *sigbuf = NULL; 620 u_char *p = NULL, *signature = NULL; 621 char *alg = NULL; 622 size_t datlen, siglen, alglen; 623 int r, is_proof = 0; 624 u_int keyid, compat; 625 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 626 627 debug3("%s", __func__); 628 629 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 630 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 631 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0 || 632 (r = sshbuf_get_u32(m, &compat)) != 0) 633 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 634 if (keyid > INT_MAX) 635 fatal("%s: invalid key ID", __func__); 636 637 /* 638 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 639 * SHA384 (48 bytes) and SHA512 (64 bytes). 640 * 641 * Otherwise, verify the signature request is for a hostkey 642 * proof. 643 * 644 * XXX perform similar check for KEX signature requests too? 645 * it's not trivial, since what is signed is the hash, rather 646 * than the full kex structure... 647 */ 648 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 649 /* 650 * Construct expected hostkey proof and compare it to what 651 * the client sent us. 652 */ 653 if (session_id2_len == 0) /* hostkeys is never first */ 654 fatal("%s: bad data length: %zu", __func__, datlen); 655 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 656 fatal("%s: no hostkey for index %d", __func__, keyid); 657 if ((sigbuf = sshbuf_new()) == NULL) 658 fatal("%s: sshbuf_new", __func__); 659 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 660 (r = sshbuf_put_string(sigbuf, session_id2, 661 session_id2_len)) != 0 || 662 (r = sshkey_puts(key, sigbuf)) != 0) 663 fatal("%s: couldn't prepare private key " 664 "proof buffer: %s", __func__, ssh_err(r)); 665 if (datlen != sshbuf_len(sigbuf) || 666 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 667 fatal("%s: bad data length: %zu, hostkey proof len %zu", 668 __func__, datlen, sshbuf_len(sigbuf)); 669 sshbuf_free(sigbuf); 670 is_proof = 1; 671 } 672 673 /* save session id, it will be passed on the first call */ 674 if (session_id2_len == 0) { 675 session_id2_len = datlen; 676 session_id2 = xmalloc(session_id2_len); 677 memcpy(session_id2, p, session_id2_len); 678 } 679 680 if ((key = get_hostkey_by_index(keyid)) != NULL) { 681 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 682 options.sk_provider, compat)) != 0) 683 fatal("%s: sshkey_sign failed: %s", 684 __func__, ssh_err(r)); 685 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 686 auth_sock > 0) { 687 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 688 p, datlen, alg, compat)) != 0) { 689 fatal("%s: ssh_agent_sign failed: %s", 690 __func__, ssh_err(r)); 691 } 692 } else 693 fatal("%s: no hostkey from index %d", __func__, keyid); 694 695 debug3("%s: %s signature %p(%zu)", __func__, 696 is_proof ? "hostkey proof" : "KEX", signature, siglen); 697 698 sshbuf_reset(m); 699 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 700 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 701 702 free(alg); 703 free(p); 704 free(signature); 705 706 mm_request_send(sock, MONITOR_ANS_SIGN, m); 707 708 /* Turn on permissions for getpwnam */ 709 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 710 711 return (0); 712 } 713 714 /* Retrieves the password entry and also checks if the user is permitted */ 715 716 int 717 mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m) 718 { 719 char *username; 720 struct passwd *pwent; 721 int r, allowed = 0; 722 u_int i; 723 724 debug3("%s", __func__); 725 726 if (authctxt->attempt++ != 0) 727 fatal("%s: multiple attempts for getpwnam", __func__); 728 729 if ((r = sshbuf_get_cstring(m, &username, NULL)) != 0) 730 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 731 732 pwent = getpwnamallow(ssh, username); 733 734 authctxt->user = xstrdup(username); 735 setproctitle("%s [priv]", pwent ? username : "unknown"); 736 free(username); 737 738 sshbuf_reset(m); 739 740 if (pwent == NULL) { 741 if ((r = sshbuf_put_u8(m, 0)) != 0) 742 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 743 authctxt->pw = fakepw(); 744 goto out; 745 } 746 747 allowed = 1; 748 authctxt->pw = pwent; 749 authctxt->valid = 1; 750 751 /* XXX don't sent pwent to unpriv; send fake class/dir/shell too */ 752 if ((r = sshbuf_put_u8(m, 1)) != 0 || 753 (r = sshbuf_put_string(m, pwent, sizeof(*pwent))) != 0 || 754 (r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || 755 (r = sshbuf_put_cstring(m, "*")) != 0 || 756 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS 757 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 || 758 #endif 759 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS 760 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 || 761 #endif 762 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 || 763 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0) 764 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 765 766 out: 767 ssh_packet_set_log_preamble(ssh, "%suser %s", 768 authctxt->valid ? "authenticating" : "invalid ", authctxt->user); 769 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0) 770 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 771 772 #define M_CP_STROPT(x) do { \ 773 if (options.x != NULL) { \ 774 if ((r = sshbuf_put_cstring(m, options.x)) != 0) \ 775 fatal("%s: buffer error: %s", \ 776 __func__, ssh_err(r)); \ 777 } \ 778 } while (0) 779 #define M_CP_STRARRAYOPT(x, nx) do { \ 780 for (i = 0; i < options.nx; i++) { \ 781 if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \ 782 fatal("%s: buffer error: %s", \ 783 __func__, ssh_err(r)); \ 784 } \ 785 } while (0) 786 /* See comment in servconf.h */ 787 COPY_MATCH_STRING_OPTS(); 788 #undef M_CP_STROPT 789 #undef M_CP_STRARRAYOPT 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 it's packet_disconnect(), but it must not allow any 796 * authentication to succeed. 797 */ 798 debug("%s: no valid authentication method lists", __func__); 799 } 800 801 debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, 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("%s: buffer error: %s", __func__, ssh_err(r)); 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("%s: buffer error: %s", __func__, ssh_err(r)); 841 debug3("%s: service=%s, style=%s", 842 __func__, authctxt->service, authctxt->style); 843 844 if (strlen(authctxt->style) == 0) { 845 free(authctxt->style); 846 authctxt->style = NULL; 847 } 848 849 return (0); 850 } 851 852 /* 853 * Check that the key type appears in the supplied pattern list, ignoring 854 * mismatches in the signature algorithm. (Signature algorithm checks are 855 * performed in the unprivileged authentication code). 856 * Returns 1 on success, 0 otherwise. 857 */ 858 static int 859 key_base_type_match(const char *method, const struct sshkey *key, 860 const char *list) 861 { 862 char *s, *l, *ol = xstrdup(list); 863 int found = 0; 864 865 l = ol; 866 for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) { 867 if (sshkey_type_from_name(s) == key->type) { 868 found = 1; 869 break; 870 } 871 } 872 if (!found) { 873 error("%s key type %s is not in permitted list %s", method, 874 sshkey_ssh_name(key), list); 875 } 876 877 free(ol); 878 return found; 879 } 880 881 int 882 mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m) 883 { 884 static int call_count; 885 char *passwd; 886 int r, authenticated; 887 size_t plen; 888 889 if (!options.password_authentication) 890 fatal("%s: password authentication not enabled", __func__); 891 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0) 892 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 893 /* Only authenticate if the context is valid */ 894 authenticated = options.password_authentication && 895 auth_password(ssh, passwd); 896 freezero(passwd, plen); 897 898 sshbuf_reset(m); 899 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 900 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 901 #ifdef USE_PAM 902 if ((r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0) 903 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 904 #endif 905 906 debug3("%s: sending result %d", __func__, authenticated); 907 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 908 909 call_count++; 910 if (plen == 0 && call_count == 1) 911 auth_method = "none"; 912 else 913 auth_method = "password"; 914 915 /* Causes monitor loop to terminate if authenticated */ 916 return (authenticated); 917 } 918 919 #ifdef BSD_AUTH 920 int 921 mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m) 922 { 923 char *name, *infotxt; 924 u_int numprompts, *echo_on, success; 925 char **prompts; 926 int r; 927 928 if (!options.kbd_interactive_authentication) 929 fatal("%s: kbd-int authentication not enabled", __func__); 930 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 931 &prompts, &echo_on) < 0 ? 0 : 1; 932 933 sshbuf_reset(m); 934 if ((r = sshbuf_put_u32(m, success)) != 0) 935 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 936 if (success) { 937 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0) 938 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 939 } 940 941 debug3("%s: sending challenge success: %u", __func__, success); 942 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 943 944 if (success) { 945 free(name); 946 free(infotxt); 947 free(prompts); 948 free(echo_on); 949 } 950 951 return (0); 952 } 953 954 int 955 mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m) 956 { 957 char *response; 958 int r, authok; 959 960 if (!options.kbd_interactive_authentication) 961 fatal("%s: kbd-int authentication not enabled", __func__); 962 if (authctxt->as == NULL) 963 fatal("%s: no bsd auth session", __func__); 964 965 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 966 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 967 authok = options.challenge_response_authentication && 968 auth_userresponse(authctxt->as, response, 0); 969 authctxt->as = NULL; 970 debug3("%s: <%s> = <%d>", __func__, response, authok); 971 free(response); 972 973 sshbuf_reset(m); 974 if ((r = sshbuf_put_u32(m, authok)) != 0) 975 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 976 977 debug3("%s: sending authenticated: %d", __func__, authok); 978 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 979 980 auth_method = "keyboard-interactive"; 981 auth_submethod = "bsdauth"; 982 983 return (authok != 0); 984 } 985 #endif 986 987 #ifdef USE_PAM 988 int 989 mm_answer_pam_start(struct ssh *ssh, int sock, struct sshbuf *m) 990 { 991 if (!options.use_pam) 992 fatal("UsePAM not set, but ended up in %s anyway", __func__); 993 994 start_pam(ssh); 995 996 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); 997 if (options.kbd_interactive_authentication) 998 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 999 1000 return (0); 1001 } 1002 1003 int 1004 mm_answer_pam_account(struct ssh *ssh, int sock, struct sshbuf *m) 1005 { 1006 u_int ret; 1007 int r; 1008 1009 if (!options.use_pam) 1010 fatal("%s: PAM not enabled", __func__); 1011 1012 ret = do_pam_account(); 1013 1014 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1015 (r = sshbuf_put_stringb(m, loginmsg)) != 0) 1016 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1017 1018 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m); 1019 1020 return (ret); 1021 } 1022 1023 static void *sshpam_ctxt, *sshpam_authok; 1024 extern KbdintDevice sshpam_device; 1025 1026 int 1027 mm_answer_pam_init_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1028 { 1029 u_int ok = 0; 1030 int r; 1031 1032 debug3("%s", __func__); 1033 if (!options.kbd_interactive_authentication) 1034 fatal("%s: kbd-int authentication not enabled", __func__); 1035 if (sshpam_ctxt != NULL) 1036 fatal("%s: already called", __func__); 1037 sshpam_ctxt = (sshpam_device.init_ctx)(authctxt); 1038 sshpam_authok = NULL; 1039 sshbuf_reset(m); 1040 if (sshpam_ctxt != NULL) { 1041 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 1042 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_QUERY, 1); 1043 ok = 1; 1044 } 1045 if ((r = sshbuf_put_u32(m, ok)) != 0) 1046 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1047 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); 1048 return (0); 1049 } 1050 1051 int 1052 mm_answer_pam_query(struct ssh *ssh, int sock, struct sshbuf *m) 1053 { 1054 char *name = NULL, *info = NULL, **prompts = NULL; 1055 u_int i, num = 0, *echo_on = 0; 1056 int r, ret; 1057 1058 debug3("%s", __func__); 1059 sshpam_authok = NULL; 1060 if (sshpam_ctxt == NULL) 1061 fatal("%s: no context", __func__); 1062 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, 1063 &num, &prompts, &echo_on); 1064 if (ret == 0 && num == 0) 1065 sshpam_authok = sshpam_ctxt; 1066 if (num > 1 || name == NULL || info == NULL) 1067 fatal("sshpam_device.query failed"); 1068 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_RESPOND, 1); 1069 sshbuf_reset(m); 1070 if ((r = sshbuf_put_u32(m, ret)) != 0 || 1071 (r = sshbuf_put_cstring(m, name)) != 0 || 1072 (r = sshbuf_put_cstring(m, info)) != 0 || 1073 (r = sshbuf_put_u32(m, sshpam_get_maxtries_reached())) != 0 || 1074 (r = sshbuf_put_u32(m, num)) != 0) 1075 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1076 free(name); 1077 free(info); 1078 for (i = 0; i < num; ++i) { 1079 if ((r = sshbuf_put_cstring(m, prompts[i])) != 0 || 1080 (r = sshbuf_put_u32(m, echo_on[i])) != 0) 1081 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1082 free(prompts[i]); 1083 } 1084 free(prompts); 1085 free(echo_on); 1086 auth_method = "keyboard-interactive"; 1087 auth_submethod = "pam"; 1088 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m); 1089 return (0); 1090 } 1091 1092 int 1093 mm_answer_pam_respond(struct ssh *ssh, int sock, struct sshbuf *m) 1094 { 1095 char **resp; 1096 u_int i, num; 1097 int r, ret; 1098 1099 debug3("%s", __func__); 1100 if (sshpam_ctxt == NULL) 1101 fatal("%s: no context", __func__); 1102 sshpam_authok = NULL; 1103 if ((r = sshbuf_get_u32(m, &num)) != 0) 1104 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1105 if (num > 0) { 1106 resp = xcalloc(num, sizeof(char *)); 1107 for (i = 0; i < num; ++i) { 1108 if ((r = sshbuf_get_cstring(m, &(resp[i]), NULL)) != 0) 1109 fatal("%s: buffer error: %s", 1110 __func__, ssh_err(r)); 1111 } 1112 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp); 1113 for (i = 0; i < num; ++i) 1114 free(resp[i]); 1115 free(resp); 1116 } else { 1117 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL); 1118 } 1119 sshbuf_reset(m); 1120 if ((r = sshbuf_put_u32(m, ret)) != 0) 1121 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1122 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m); 1123 auth_method = "keyboard-interactive"; 1124 auth_submethod = "pam"; 1125 if (ret == 0) 1126 sshpam_authok = sshpam_ctxt; 1127 return (0); 1128 } 1129 1130 int 1131 mm_answer_pam_free_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1132 { 1133 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt; 1134 1135 debug3("%s", __func__); 1136 if (sshpam_ctxt == NULL) 1137 fatal("%s: no context", __func__); 1138 (sshpam_device.free_ctx)(sshpam_ctxt); 1139 sshpam_ctxt = sshpam_authok = NULL; 1140 sshbuf_reset(m); 1141 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); 1142 /* Allow another attempt */ 1143 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 1144 auth_method = "keyboard-interactive"; 1145 auth_submethod = "pam"; 1146 return r; 1147 } 1148 #endif 1149 1150 int 1151 mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m) 1152 { 1153 struct sshkey *key = NULL; 1154 char *cuser, *chost; 1155 u_int pubkey_auth_attempt; 1156 enum mm_keytype type = 0; 1157 int r, allowed = 0; 1158 struct sshauthopt *opts = NULL; 1159 1160 debug3("%s entering", __func__); 1161 if ((r = sshbuf_get_u32(m, &type)) != 0 || 1162 (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 || 1163 (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 || 1164 (r = sshkey_froms(m, &key)) != 0 || 1165 (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0) 1166 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1167 1168 debug3("%s: key_from_blob: %p", __func__, key); 1169 1170 if (key != NULL && authctxt->valid) { 1171 /* These should not make it past the privsep child */ 1172 if (sshkey_type_plain(key->type) == KEY_RSA && 1173 (datafellows & SSH_BUG_RSASIGMD5) != 0) 1174 fatal("%s: passed a SSH_BUG_RSASIGMD5 key", __func__); 1175 1176 switch (type) { 1177 case MM_USERKEY: 1178 auth_method = "publickey"; 1179 if (!options.pubkey_authentication) 1180 break; 1181 if (auth2_key_already_used(authctxt, key)) 1182 break; 1183 if (!key_base_type_match(auth_method, key, 1184 options.pubkey_key_types)) 1185 break; 1186 allowed = user_key_allowed(ssh, authctxt->pw, key, 1187 pubkey_auth_attempt, &opts); 1188 break; 1189 case MM_HOSTKEY: 1190 auth_method = "hostbased"; 1191 if (!options.hostbased_authentication) 1192 break; 1193 if (auth2_key_already_used(authctxt, key)) 1194 break; 1195 if (!key_base_type_match(auth_method, key, 1196 options.hostbased_key_types)) 1197 break; 1198 allowed = hostbased_key_allowed(ssh, authctxt->pw, 1199 cuser, chost, key); 1200 auth2_record_info(authctxt, 1201 "client user \"%.100s\", client host \"%.100s\"", 1202 cuser, chost); 1203 break; 1204 default: 1205 fatal("%s: unknown key type %d", __func__, type); 1206 break; 1207 } 1208 } 1209 1210 debug3("%s: %s authentication%s: %s key is %s", __func__, 1211 auth_method, pubkey_auth_attempt ? "" : " test", 1212 (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key), 1213 allowed ? "allowed" : "not allowed"); 1214 1215 auth2_record_key(authctxt, 0, key); 1216 1217 /* clear temporarily storage (used by verify) */ 1218 monitor_reset_key_state(); 1219 1220 if (allowed) { 1221 /* Save temporarily for comparison in verify */ 1222 if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0) 1223 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1224 key_blobtype = type; 1225 key_opts = opts; 1226 hostbased_cuser = cuser; 1227 hostbased_chost = chost; 1228 } else { 1229 /* Log failed attempt */ 1230 auth_log(ssh, 0, 0, auth_method, NULL); 1231 free(cuser); 1232 free(chost); 1233 } 1234 sshkey_free(key); 1235 1236 sshbuf_reset(m); 1237 if ((r = sshbuf_put_u32(m, allowed)) != 0) 1238 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1239 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0) 1240 fatal("%s: sshauthopt_serialise: %s", __func__, ssh_err(r)); 1241 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 1242 1243 if (!allowed) 1244 sshauthopt_free(opts); 1245 1246 return (0); 1247 } 1248 1249 static int 1250 monitor_valid_userblob(const u_char *data, u_int datalen) 1251 { 1252 struct sshbuf *b; 1253 const u_char *p; 1254 char *userstyle, *cp; 1255 size_t len; 1256 u_char type; 1257 int r, fail = 0; 1258 1259 if ((b = sshbuf_from(data, datalen)) == NULL) 1260 fatal("%s: sshbuf_from", __func__); 1261 1262 if (datafellows & SSH_OLD_SESSIONID) { 1263 p = sshbuf_ptr(b); 1264 len = sshbuf_len(b); 1265 if ((session_id2 == NULL) || 1266 (len < session_id2_len) || 1267 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1268 fail++; 1269 if ((r = sshbuf_consume(b, session_id2_len)) != 0) 1270 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1271 } else { 1272 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1273 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1274 if ((session_id2 == NULL) || 1275 (len != session_id2_len) || 1276 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1277 fail++; 1278 } 1279 if ((r = sshbuf_get_u8(b, &type)) != 0) 1280 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1281 if (type != SSH2_MSG_USERAUTH_REQUEST) 1282 fail++; 1283 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1284 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1285 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1286 authctxt->style ? ":" : "", 1287 authctxt->style ? authctxt->style : ""); 1288 if (strcmp(userstyle, cp) != 0) { 1289 logit("wrong user name passed to monitor: " 1290 "expected %s != %.100s", userstyle, cp); 1291 fail++; 1292 } 1293 free(userstyle); 1294 free(cp); 1295 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1296 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1297 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1298 if (strcmp("publickey", cp) != 0) 1299 fail++; 1300 free(cp); 1301 if ((r = sshbuf_get_u8(b, &type)) != 0) 1302 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1303 if (type == 0) 1304 fail++; 1305 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1306 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1307 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1308 if (sshbuf_len(b) != 0) 1309 fail++; 1310 sshbuf_free(b); 1311 return (fail == 0); 1312 } 1313 1314 static int 1315 monitor_valid_hostbasedblob(const u_char *data, u_int datalen, 1316 const char *cuser, const char *chost) 1317 { 1318 struct sshbuf *b; 1319 const u_char *p; 1320 char *cp, *userstyle; 1321 size_t len; 1322 int r, fail = 0; 1323 u_char type; 1324 1325 if ((b = sshbuf_from(data, datalen)) == NULL) 1326 fatal("%s: sshbuf_new", __func__); 1327 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1328 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1329 1330 if ((session_id2 == NULL) || 1331 (len != session_id2_len) || 1332 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1333 fail++; 1334 1335 if ((r = sshbuf_get_u8(b, &type)) != 0) 1336 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1337 if (type != SSH2_MSG_USERAUTH_REQUEST) 1338 fail++; 1339 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1340 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1341 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1342 authctxt->style ? ":" : "", 1343 authctxt->style ? authctxt->style : ""); 1344 if (strcmp(userstyle, cp) != 0) { 1345 logit("wrong user name passed to monitor: " 1346 "expected %s != %.100s", userstyle, cp); 1347 fail++; 1348 } 1349 free(userstyle); 1350 free(cp); 1351 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1352 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1353 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1354 if (strcmp(cp, "hostbased") != 0) 1355 fail++; 1356 free(cp); 1357 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1358 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1359 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1360 1361 /* verify client host, strip trailing dot if necessary */ 1362 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1363 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1364 if (((len = strlen(cp)) > 0) && cp[len - 1] == '.') 1365 cp[len - 1] = '\0'; 1366 if (strcmp(cp, chost) != 0) 1367 fail++; 1368 free(cp); 1369 1370 /* verify client user */ 1371 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1372 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1373 if (strcmp(cp, cuser) != 0) 1374 fail++; 1375 free(cp); 1376 1377 if (sshbuf_len(b) != 0) 1378 fail++; 1379 sshbuf_free(b); 1380 return (fail == 0); 1381 } 1382 1383 int 1384 mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m) 1385 { 1386 struct sshkey *key; 1387 const u_char *signature, *data, *blob; 1388 char *sigalg = NULL, *fp = NULL; 1389 size_t signaturelen, datalen, bloblen; 1390 int r, ret, req_presence = 0, valid_data = 0, encoded_ret; 1391 struct sshkey_sig_details *sig_details = NULL; 1392 1393 if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 || 1394 (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 || 1395 (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 || 1396 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0) 1397 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1398 1399 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1400 !monitor_allowed_key(blob, bloblen)) 1401 fatal("%s: bad key, not previously allowed", __func__); 1402 1403 /* Empty signature algorithm means NULL. */ 1404 if (*sigalg == '\0') { 1405 free(sigalg); 1406 sigalg = NULL; 1407 } 1408 1409 /* XXX use sshkey_froms here; need to change key_blob, etc. */ 1410 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0) 1411 fatal("%s: bad public key blob: %s", __func__, ssh_err(r)); 1412 1413 switch (key_blobtype) { 1414 case MM_USERKEY: 1415 valid_data = monitor_valid_userblob(data, datalen); 1416 auth_method = "publickey"; 1417 break; 1418 case MM_HOSTKEY: 1419 valid_data = monitor_valid_hostbasedblob(data, datalen, 1420 hostbased_cuser, hostbased_chost); 1421 auth_method = "hostbased"; 1422 break; 1423 default: 1424 valid_data = 0; 1425 break; 1426 } 1427 if (!valid_data) 1428 fatal("%s: bad signature data blob", __func__); 1429 1430 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 1431 SSH_FP_DEFAULT)) == NULL) 1432 fatal("%s: sshkey_fingerprint failed", __func__); 1433 1434 ret = sshkey_verify(key, signature, signaturelen, data, datalen, 1435 sigalg, ssh->compat, &sig_details); 1436 debug3("%s: %s %p signature %s%s%s", __func__, auth_method, key, 1437 (ret == 0) ? "verified" : "unverified", 1438 (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : ""); 1439 1440 if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) { 1441 req_presence = (options.pubkey_auth_options & 1442 PUBKEYAUTH_TOUCH_REQUIRED) || 1443 !key_opts->no_require_user_presence; 1444 if (req_presence && 1445 (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) { 1446 error("public key %s %s signature for %s%s from %.128s " 1447 "port %d rejected: user presence " 1448 "(authenticator touch) requirement not met ", 1449 sshkey_type(key), fp, 1450 authctxt->valid ? "" : "invalid user ", 1451 authctxt->user, ssh_remote_ipaddr(ssh), 1452 ssh_remote_port(ssh)); 1453 ret = SSH_ERR_SIGNATURE_INVALID; 1454 } 1455 } 1456 auth2_record_key(authctxt, ret == 0, key); 1457 1458 if (key_blobtype == MM_USERKEY) 1459 auth_activate_options(ssh, key_opts); 1460 monitor_reset_key_state(); 1461 1462 sshbuf_reset(m); 1463 1464 /* encode ret != 0 as positive integer, since we're sending u32 */ 1465 encoded_ret = (ret != 0); 1466 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 || 1467 (r = sshbuf_put_u8(m, sig_details != NULL)) != 0) 1468 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1469 if (sig_details != NULL) { 1470 if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 || 1471 (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0) 1472 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1473 } 1474 sshkey_sig_details_free(sig_details); 1475 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1476 1477 free(sigalg); 1478 free(fp); 1479 sshkey_free(key); 1480 1481 return ret == 0; 1482 } 1483 1484 static void 1485 mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw) 1486 { 1487 socklen_t fromlen; 1488 struct sockaddr_storage from; 1489 1490 /* 1491 * Get IP address of client. If the connection is not a socket, let 1492 * the address be 0.0.0.0. 1493 */ 1494 memset(&from, 0, sizeof(from)); 1495 fromlen = sizeof(from); 1496 if (ssh_packet_connection_is_on_socket(ssh)) { 1497 if (getpeername(ssh_packet_get_connection_in(ssh), 1498 (struct sockaddr *)&from, &fromlen) == -1) { 1499 debug("getpeername: %.100s", strerror(errno)); 1500 cleanup_exit(255); 1501 } 1502 } 1503 /* Record that there was a login on that tty from the remote host. */ 1504 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1505 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1506 (struct sockaddr *)&from, fromlen); 1507 } 1508 1509 static void 1510 mm_session_close(Session *s) 1511 { 1512 debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid); 1513 if (s->ttyfd != -1) { 1514 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd); 1515 session_pty_cleanup2(s); 1516 } 1517 session_unused(s->self); 1518 } 1519 1520 int 1521 mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m) 1522 { 1523 extern struct monitor *pmonitor; 1524 Session *s; 1525 int r, res, fd0; 1526 1527 debug3("%s entering", __func__); 1528 1529 sshbuf_reset(m); 1530 s = session_new(); 1531 if (s == NULL) 1532 goto error; 1533 s->authctxt = authctxt; 1534 s->pw = authctxt->pw; 1535 s->pid = pmonitor->m_pid; 1536 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1537 if (res == 0) 1538 goto error; 1539 pty_setowner(authctxt->pw, s->tty); 1540 1541 if ((r = sshbuf_put_u32(m, 1)) != 0 || 1542 (r = sshbuf_put_cstring(m, s->tty)) != 0) 1543 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1544 1545 /* We need to trick ttyslot */ 1546 if (dup2(s->ttyfd, 0) == -1) 1547 fatal("%s: dup2", __func__); 1548 1549 mm_record_login(ssh, s, authctxt->pw); 1550 1551 /* Now we can close the file descriptor again */ 1552 close(0); 1553 1554 /* send messages generated by record_login */ 1555 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0) 1556 fatal("%s: put login message: %s", __func__, ssh_err(r)); 1557 sshbuf_reset(loginmsg); 1558 1559 mm_request_send(sock, MONITOR_ANS_PTY, m); 1560 1561 if (mm_send_fd(sock, s->ptyfd) == -1 || 1562 mm_send_fd(sock, s->ttyfd) == -1) 1563 fatal("%s: send fds failed", __func__); 1564 1565 /* make sure nothing uses fd 0 */ 1566 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1567 fatal("%s: open(/dev/null): %s", __func__, strerror(errno)); 1568 if (fd0 != 0) 1569 error("%s: fd0 %d != 0", __func__, fd0); 1570 1571 /* slave is not needed */ 1572 close(s->ttyfd); 1573 s->ttyfd = s->ptyfd; 1574 /* no need to dup() because nobody closes ptyfd */ 1575 s->ptymaster = s->ptyfd; 1576 1577 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd); 1578 1579 return (0); 1580 1581 error: 1582 if (s != NULL) 1583 mm_session_close(s); 1584 if ((r = sshbuf_put_u32(m, 0)) != 0) 1585 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1586 mm_request_send(sock, MONITOR_ANS_PTY, m); 1587 return (0); 1588 } 1589 1590 int 1591 mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m) 1592 { 1593 Session *s; 1594 char *tty; 1595 int r; 1596 1597 debug3("%s entering", __func__); 1598 1599 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0) 1600 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1601 if ((s = session_by_tty(tty)) != NULL) 1602 mm_session_close(s); 1603 sshbuf_reset(m); 1604 free(tty); 1605 return (0); 1606 } 1607 1608 int 1609 mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req) 1610 { 1611 extern struct monitor *pmonitor; 1612 int res, status; 1613 1614 debug3("%s: tearing down sessions", __func__); 1615 1616 /* The child is terminating */ 1617 session_destroy_all(ssh, &mm_session_close); 1618 1619 #ifdef USE_PAM 1620 if (options.use_pam) 1621 sshpam_cleanup(); 1622 #endif 1623 1624 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1625 if (errno != EINTR) 1626 exit(1); 1627 1628 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1629 1630 /* Terminate process */ 1631 exit(res); 1632 } 1633 1634 #ifdef SSH_AUDIT_EVENTS 1635 /* Report that an audit event occurred */ 1636 int 1637 mm_answer_audit_event(struct ssh *ssh, int socket, struct sshbuf *m) 1638 { 1639 u_int n; 1640 ssh_audit_event_t event; 1641 int r; 1642 1643 debug3("%s entering", __func__); 1644 1645 if ((r = sshbuf_get_u32(m, &n)) != 0) 1646 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1647 event = (ssh_audit_event_t)n; 1648 switch (event) { 1649 case SSH_AUTH_FAIL_PUBKEY: 1650 case SSH_AUTH_FAIL_HOSTBASED: 1651 case SSH_AUTH_FAIL_GSSAPI: 1652 case SSH_LOGIN_EXCEED_MAXTRIES: 1653 case SSH_LOGIN_ROOT_DENIED: 1654 case SSH_CONNECTION_CLOSE: 1655 case SSH_INVALID_USER: 1656 audit_event(ssh, event); 1657 break; 1658 default: 1659 fatal("Audit event type %d not permitted", event); 1660 } 1661 1662 return (0); 1663 } 1664 1665 int 1666 mm_answer_audit_command(struct ssh *ssh, int socket, struct sshbuf *m) 1667 { 1668 char *cmd; 1669 int r; 1670 1671 debug3("%s entering", __func__); 1672 if ((r = sshbuf_get_cstring(m, &cmd, NULL)) != 0) 1673 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1674 /* sanity check command, if so how? */ 1675 audit_run_command(cmd); 1676 free(cmd); 1677 return (0); 1678 } 1679 #endif /* SSH_AUDIT_EVENTS */ 1680 1681 void 1682 monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor) 1683 { 1684 ssh_clear_newkeys(ssh, MODE_IN); 1685 ssh_clear_newkeys(ssh, MODE_OUT); 1686 sshbuf_free(child_state); 1687 child_state = NULL; 1688 } 1689 1690 void 1691 monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor) 1692 { 1693 struct kex *kex; 1694 int r; 1695 1696 debug3("%s: packet_set_state", __func__); 1697 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1698 fatal("%s: packet_set_state: %s", __func__, ssh_err(r)); 1699 sshbuf_free(child_state); 1700 child_state = NULL; 1701 1702 if ((kex = ssh->kex) != NULL) { 1703 /* XXX set callbacks */ 1704 #ifdef WITH_OPENSSL 1705 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server; 1706 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server; 1707 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server; 1708 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server; 1709 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server; 1710 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1711 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1712 # ifdef OPENSSL_HAS_ECC 1713 kex->kex[KEX_ECDH_SHA2] = kex_gen_server; 1714 # endif 1715 #endif /* WITH_OPENSSL */ 1716 kex->kex[KEX_C25519_SHA256] = kex_gen_server; 1717 kex->kex[KEX_KEM_SNTRUP4591761X25519_SHA512] = kex_gen_server; 1718 kex->load_host_public_key=&get_hostkey_public_by_type; 1719 kex->load_host_private_key=&get_hostkey_private_by_type; 1720 kex->host_key_index=&get_hostkey_index; 1721 kex->sign = sshd_hostkey_sign; 1722 } 1723 } 1724 1725 /* This function requires careful sanity checking */ 1726 1727 void 1728 mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor) 1729 { 1730 debug3("%s: Waiting for new keys", __func__); 1731 1732 if ((child_state = sshbuf_new()) == NULL) 1733 fatal("%s: sshbuf_new failed", __func__); 1734 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1735 child_state); 1736 debug3("%s: GOT new keys", __func__); 1737 } 1738 1739 1740 /* XXX */ 1741 1742 #define FD_CLOSEONEXEC(x) do { \ 1743 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1744 fatal("fcntl(%d, F_SETFD)", x); \ 1745 } while (0) 1746 1747 static void 1748 monitor_openfds(struct monitor *mon, int do_logfds) 1749 { 1750 int pair[2]; 1751 #ifdef SO_ZEROIZE 1752 int on = 1; 1753 #endif 1754 1755 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1756 fatal("%s: socketpair: %s", __func__, strerror(errno)); 1757 #ifdef SO_ZEROIZE 1758 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1759 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno)); 1760 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1761 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno)); 1762 #endif 1763 FD_CLOSEONEXEC(pair[0]); 1764 FD_CLOSEONEXEC(pair[1]); 1765 mon->m_recvfd = pair[0]; 1766 mon->m_sendfd = pair[1]; 1767 1768 if (do_logfds) { 1769 if (pipe(pair) == -1) 1770 fatal("%s: pipe: %s", __func__, strerror(errno)); 1771 FD_CLOSEONEXEC(pair[0]); 1772 FD_CLOSEONEXEC(pair[1]); 1773 mon->m_log_recvfd = pair[0]; 1774 mon->m_log_sendfd = pair[1]; 1775 } else 1776 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1777 } 1778 1779 #define MM_MEMSIZE 65536 1780 1781 struct monitor * 1782 monitor_init(void) 1783 { 1784 struct monitor *mon; 1785 1786 mon = xcalloc(1, sizeof(*mon)); 1787 monitor_openfds(mon, 1); 1788 1789 return mon; 1790 } 1791 1792 void 1793 monitor_reinit(struct monitor *mon) 1794 { 1795 monitor_openfds(mon, 0); 1796 } 1797 1798 #ifdef GSSAPI 1799 int 1800 mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1801 { 1802 gss_OID_desc goid; 1803 OM_uint32 major; 1804 size_t len; 1805 u_char *p; 1806 int r; 1807 1808 if (!options.gss_authentication) 1809 fatal("%s: GSSAPI authentication not enabled", __func__); 1810 1811 if ((r = sshbuf_get_string(m, &p, &len)) != 0) 1812 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1813 goid.elements = p; 1814 goid.length = len; 1815 1816 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1817 1818 free(goid.elements); 1819 1820 sshbuf_reset(m); 1821 if ((r = sshbuf_put_u32(m, major)) != 0) 1822 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1823 1824 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1825 1826 /* Now we have a context, enable the step */ 1827 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1828 1829 return (0); 1830 } 1831 1832 int 1833 mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1834 { 1835 gss_buffer_desc in; 1836 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1837 OM_uint32 major, minor; 1838 OM_uint32 flags = 0; /* GSI needs this */ 1839 int r; 1840 1841 if (!options.gss_authentication) 1842 fatal("%s: GSSAPI authentication not enabled", __func__); 1843 1844 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0) 1845 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1846 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1847 free(in.value); 1848 1849 sshbuf_reset(m); 1850 if ((r = sshbuf_put_u32(m, major)) != 0 || 1851 (r = sshbuf_put_string(m, out.value, out.length)) != 0 || 1852 (r = sshbuf_put_u32(m, flags)) != 0) 1853 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1854 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1855 1856 gss_release_buffer(&minor, &out); 1857 1858 if (major == GSS_S_COMPLETE) { 1859 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1860 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1861 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1862 } 1863 return (0); 1864 } 1865 1866 int 1867 mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m) 1868 { 1869 gss_buffer_desc gssbuf, mic; 1870 OM_uint32 ret; 1871 int r; 1872 1873 if (!options.gss_authentication) 1874 fatal("%s: GSSAPI authentication not enabled", __func__); 1875 1876 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 || 1877 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0) 1878 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1879 1880 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1881 1882 free(gssbuf.value); 1883 free(mic.value); 1884 1885 sshbuf_reset(m); 1886 if ((r = sshbuf_put_u32(m, ret)) != 0) 1887 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1888 1889 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1890 1891 if (!GSS_ERROR(ret)) 1892 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1893 1894 return (0); 1895 } 1896 1897 int 1898 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m) 1899 { 1900 int r, authenticated; 1901 const char *displayname; 1902 1903 if (!options.gss_authentication) 1904 fatal("%s: GSSAPI authentication not enabled", __func__); 1905 1906 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1907 1908 sshbuf_reset(m); 1909 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 1910 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1911 1912 debug3("%s: sending result %d", __func__, authenticated); 1913 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1914 1915 auth_method = "gssapi-with-mic"; 1916 1917 if ((displayname = ssh_gssapi_displayname()) != NULL) 1918 auth2_record_info(authctxt, "%s", displayname); 1919 1920 /* Monitor loop will terminate if authenticated */ 1921 return (authenticated); 1922 } 1923 #endif /* GSSAPI */ 1924 1925