1 /* $OpenBSD: monitor.c,v 1.213 2020/08/27 01:06:18 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 <sys/types.h> 29 #include <sys/wait.h> 30 #include <sys/socket.h> 31 #include <sys/tree.h> 32 #include <sys/queue.h> 33 34 #ifdef WITH_OPENSSL 35 #include <openssl/dh.h> 36 #endif 37 38 #include <errno.h> 39 #include <fcntl.h> 40 #include <limits.h> 41 #include <paths.h> 42 #include <poll.h> 43 #include <pwd.h> 44 #include <signal.h> 45 #include <stdarg.h> 46 #include <stdint.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <unistd.h> 51 52 #include "atomicio.h" 53 #include "xmalloc.h" 54 #include "ssh.h" 55 #include "sshkey.h" 56 #include "sshbuf.h" 57 #include "hostfile.h" 58 #include "auth.h" 59 #include "cipher.h" 60 #include "kex.h" 61 #include "dh.h" 62 #include "packet.h" 63 #include "auth-options.h" 64 #include "sshpty.h" 65 #include "channels.h" 66 #include "session.h" 67 #include "sshlogin.h" 68 #include "canohost.h" 69 #include "log.h" 70 #include "misc.h" 71 #include "servconf.h" 72 #include "monitor.h" 73 #ifdef GSSAPI 74 #include "ssh-gss.h" 75 #endif 76 #include "monitor_wrap.h" 77 #include "monitor_fdpass.h" 78 #include "compat.h" 79 #include "ssh2.h" 80 #include "authfd.h" 81 #include "match.h" 82 #include "ssherr.h" 83 #include "sk-api.h" 84 85 #ifdef GSSAPI 86 static Gssctxt *gsscontext = NULL; 87 #endif 88 89 /* Imports */ 90 extern ServerOptions options; 91 extern u_int utmp_len; 92 extern u_char session_id[]; 93 extern struct sshbuf *loginmsg; 94 extern struct sshauthopt *auth_opts; /* XXX move to permanent ssh->authctxt? */ 95 96 /* State exported from the child */ 97 static struct sshbuf *child_state; 98 99 /* Functions on the monitor that answer unprivileged requests */ 100 101 int mm_answer_moduli(struct ssh *, int, struct sshbuf *); 102 int mm_answer_sign(struct ssh *, int, struct sshbuf *); 103 int mm_answer_pwnamallow(struct ssh *, int, struct sshbuf *); 104 int mm_answer_auth2_read_banner(struct ssh *, int, struct sshbuf *); 105 int mm_answer_authserv(struct ssh *, int, struct sshbuf *); 106 int mm_answer_authpassword(struct ssh *, int, struct sshbuf *); 107 int mm_answer_bsdauthquery(struct ssh *, int, struct sshbuf *); 108 int mm_answer_bsdauthrespond(struct ssh *, int, struct sshbuf *); 109 int mm_answer_skeyquery(struct ssh *, int, struct sshbuf *); 110 int mm_answer_skeyrespond(struct ssh *, int, struct sshbuf *); 111 int mm_answer_keyallowed(struct ssh *, int, struct sshbuf *); 112 int mm_answer_keyverify(struct ssh *, int, struct sshbuf *); 113 int mm_answer_pty(struct ssh *, int, struct sshbuf *); 114 int mm_answer_pty_cleanup(struct ssh *, int, struct sshbuf *); 115 int mm_answer_term(struct ssh *, int, struct sshbuf *); 116 int mm_answer_rsa_keyallowed(struct ssh *, int, struct sshbuf *); 117 int mm_answer_rsa_challenge(struct ssh *, int, struct sshbuf *); 118 int mm_answer_rsa_response(struct ssh *, int, struct sshbuf *); 119 int mm_answer_sesskey(struct ssh *, int, struct sshbuf *); 120 int mm_answer_sessid(struct ssh *, int, struct sshbuf *); 121 122 #ifdef GSSAPI 123 int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *); 124 int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *); 125 int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *); 126 int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *); 127 #endif 128 129 static Authctxt *authctxt; 130 131 /* local state for key verify */ 132 static u_char *key_blob = NULL; 133 static size_t key_bloblen = 0; 134 static int key_blobtype = MM_NOKEY; 135 static struct sshauthopt *key_opts = NULL; 136 static char *hostbased_cuser = NULL; 137 static char *hostbased_chost = NULL; 138 static char *auth_method = "unknown"; 139 static char *auth_submethod = NULL; 140 static u_int session_id2_len = 0; 141 static u_char *session_id2 = NULL; 142 static pid_t monitor_child_pid; 143 144 struct mon_table { 145 enum monitor_reqtype type; 146 int flags; 147 int (*f)(struct ssh *, int, struct sshbuf *); 148 }; 149 150 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 151 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 152 #define MON_ONCE 0x0010 /* Disable after calling */ 153 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 154 155 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 156 157 #define MON_PERMIT 0x1000 /* Request is permitted */ 158 159 static int monitor_read(struct ssh *, struct monitor *, struct mon_table *, 160 struct mon_table **); 161 static int monitor_read_log(struct monitor *); 162 163 struct mon_table mon_dispatch_proto20[] = { 164 #ifdef WITH_OPENSSL 165 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 166 #endif 167 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 168 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 169 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 170 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 171 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 172 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 173 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 174 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 175 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 176 #ifdef GSSAPI 177 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 178 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx}, 179 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok}, 180 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic}, 181 #endif 182 {0, 0, NULL} 183 }; 184 185 struct mon_table mon_dispatch_postauth20[] = { 186 #ifdef WITH_OPENSSL 187 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 188 #endif 189 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 190 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 191 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 192 {MONITOR_REQ_TERM, 0, mm_answer_term}, 193 {0, 0, NULL} 194 }; 195 196 struct mon_table *mon_dispatch; 197 198 /* Specifies if a certain message is allowed at the moment */ 199 static void 200 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 201 { 202 while (ent->f != NULL) { 203 if (ent->type == type) { 204 ent->flags &= ~MON_PERMIT; 205 ent->flags |= permit ? MON_PERMIT : 0; 206 return; 207 } 208 ent++; 209 } 210 } 211 212 static void 213 monitor_permit_authentications(int permit) 214 { 215 struct mon_table *ent = mon_dispatch; 216 217 while (ent->f != NULL) { 218 if (ent->flags & MON_AUTH) { 219 ent->flags &= ~MON_PERMIT; 220 ent->flags |= permit ? MON_PERMIT : 0; 221 } 222 ent++; 223 } 224 } 225 226 void 227 monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor) 228 { 229 struct mon_table *ent; 230 int authenticated = 0, partial = 0; 231 232 debug3("preauth child monitor started"); 233 234 if (pmonitor->m_recvfd >= 0) 235 close(pmonitor->m_recvfd); 236 if (pmonitor->m_log_sendfd >= 0) 237 close(pmonitor->m_log_sendfd); 238 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 239 240 authctxt = (Authctxt *)ssh->authctxt; 241 memset(authctxt, 0, sizeof(*authctxt)); 242 ssh->authctxt = authctxt; 243 244 mon_dispatch = mon_dispatch_proto20; 245 /* Permit requests for moduli and signatures */ 246 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 247 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 248 249 /* The first few requests do not require asynchronous access */ 250 while (!authenticated) { 251 partial = 0; 252 auth_method = "unknown"; 253 auth_submethod = NULL; 254 auth2_authctxt_reset_info(authctxt); 255 256 authenticated = (monitor_read(ssh, pmonitor, 257 mon_dispatch, &ent) == 1); 258 259 /* Special handling for multiple required authentications */ 260 if (options.num_auth_methods != 0) { 261 if (authenticated && 262 !auth2_update_methods_lists(authctxt, 263 auth_method, auth_submethod)) { 264 debug3("%s: method %s: partial", __func__, 265 auth_method); 266 authenticated = 0; 267 partial = 1; 268 } 269 } 270 271 if (authenticated) { 272 if (!(ent->flags & MON_AUTHDECIDE)) 273 fatal("%s: unexpected authentication from %d", 274 __func__, ent->type); 275 if (authctxt->pw->pw_uid == 0 && 276 !auth_root_allowed(ssh, auth_method)) 277 authenticated = 0; 278 } 279 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 280 auth_log(ssh, authenticated, partial, 281 auth_method, auth_submethod); 282 if (!partial && !authenticated) 283 authctxt->failures++; 284 if (authenticated || partial) { 285 auth2_update_session_info(authctxt, 286 auth_method, auth_submethod); 287 } 288 } 289 } 290 291 if (!authctxt->valid) 292 fatal("%s: authenticated invalid user", __func__); 293 if (strcmp(auth_method, "unknown") == 0) 294 fatal("%s: authentication method name unknown", __func__); 295 296 debug("%s: %s has been authenticated by privileged process", 297 __func__, authctxt->user); 298 ssh->authctxt = NULL; 299 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 300 301 mm_get_keystate(ssh, pmonitor); 302 303 /* Drain any buffered messages from the child */ 304 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 305 ; 306 307 if (pmonitor->m_recvfd >= 0) 308 close(pmonitor->m_recvfd); 309 if (pmonitor->m_log_sendfd >= 0) 310 close(pmonitor->m_log_sendfd); 311 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 312 } 313 314 static void 315 monitor_set_child_handler(pid_t pid) 316 { 317 monitor_child_pid = pid; 318 } 319 320 static void 321 monitor_child_handler(int sig) 322 { 323 kill(monitor_child_pid, sig); 324 } 325 326 void 327 monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor) 328 { 329 close(pmonitor->m_recvfd); 330 pmonitor->m_recvfd = -1; 331 332 monitor_set_child_handler(pmonitor->m_pid); 333 ssh_signal(SIGHUP, &monitor_child_handler); 334 ssh_signal(SIGTERM, &monitor_child_handler); 335 ssh_signal(SIGINT, &monitor_child_handler); 336 337 mon_dispatch = mon_dispatch_postauth20; 338 339 /* Permit requests for moduli and signatures */ 340 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 341 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 342 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 343 344 if (auth_opts->permit_pty_flag) { 345 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 346 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 347 } 348 349 for (;;) 350 monitor_read(ssh, pmonitor, mon_dispatch, NULL); 351 } 352 353 static int 354 monitor_read_log(struct monitor *pmonitor) 355 { 356 struct sshbuf *logmsg; 357 u_int len, level; 358 char *msg; 359 u_char *p; 360 int r; 361 362 if ((logmsg = sshbuf_new()) == NULL) 363 fatal("%s: sshbuf_new", __func__); 364 365 /* Read length */ 366 if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0) 367 fatal("%s: reserve: %s", __func__, ssh_err(r)); 368 if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) { 369 if (errno == EPIPE) { 370 sshbuf_free(logmsg); 371 debug("%s: child log fd closed", __func__); 372 close(pmonitor->m_log_recvfd); 373 pmonitor->m_log_recvfd = -1; 374 return -1; 375 } 376 fatal("%s: log fd read: %s", __func__, strerror(errno)); 377 } 378 if ((r = sshbuf_get_u32(logmsg, &len)) != 0) 379 fatal("%s: get len: %s", __func__, ssh_err(r)); 380 if (len <= 4 || len > 8192) 381 fatal("%s: invalid log message length %u", __func__, len); 382 383 /* Read severity, message */ 384 sshbuf_reset(logmsg); 385 if ((r = sshbuf_reserve(logmsg, len, &p)) != 0) 386 fatal("%s: reserve: %s", __func__, ssh_err(r)); 387 if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len) 388 fatal("%s: log fd read: %s", __func__, strerror(errno)); 389 if ((r = sshbuf_get_u32(logmsg, &level)) != 0 || 390 (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0) 391 fatal("%s: decode: %s", __func__, ssh_err(r)); 392 393 /* Log it */ 394 if (log_level_name(level) == NULL) 395 fatal("%s: invalid log level %u (corrupted message?)", 396 __func__, level); 397 do_log2(level, "%s [preauth]", msg); 398 399 sshbuf_free(logmsg); 400 free(msg); 401 402 return 0; 403 } 404 405 static int 406 monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent, 407 struct mon_table **pent) 408 { 409 struct sshbuf *m; 410 int r, ret; 411 u_char type; 412 struct pollfd pfd[2]; 413 414 for (;;) { 415 memset(&pfd, 0, sizeof(pfd)); 416 pfd[0].fd = pmonitor->m_sendfd; 417 pfd[0].events = POLLIN; 418 pfd[1].fd = pmonitor->m_log_recvfd; 419 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 420 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 421 if (errno == EINTR || errno == EAGAIN) 422 continue; 423 fatal("%s: poll: %s", __func__, strerror(errno)); 424 } 425 if (pfd[1].revents) { 426 /* 427 * Drain all log messages before processing next 428 * monitor request. 429 */ 430 monitor_read_log(pmonitor); 431 continue; 432 } 433 if (pfd[0].revents) 434 break; /* Continues below */ 435 } 436 437 if ((m = sshbuf_new()) == NULL) 438 fatal("%s: sshbuf_new", __func__); 439 440 mm_request_receive(pmonitor->m_sendfd, m); 441 if ((r = sshbuf_get_u8(m, &type)) != 0) 442 fatal("%s: decode: %s", __func__, ssh_err(r)); 443 444 debug3("%s: checking request %d", __func__, type); 445 446 while (ent->f != NULL) { 447 if (ent->type == type) 448 break; 449 ent++; 450 } 451 452 if (ent->f != NULL) { 453 if (!(ent->flags & MON_PERMIT)) 454 fatal("%s: unpermitted request %d", __func__, 455 type); 456 ret = (*ent->f)(ssh, pmonitor->m_sendfd, m); 457 sshbuf_free(m); 458 459 /* The child may use this request only once, disable it */ 460 if (ent->flags & MON_ONCE) { 461 debug2("%s: %d used once, disabling now", __func__, 462 type); 463 ent->flags &= ~MON_PERMIT; 464 } 465 466 if (pent != NULL) 467 *pent = ent; 468 469 return ret; 470 } 471 472 fatal("%s: unsupported request: %d", __func__, type); 473 474 /* NOTREACHED */ 475 return (-1); 476 } 477 478 /* allowed key state */ 479 static int 480 monitor_allowed_key(const u_char *blob, u_int bloblen) 481 { 482 /* make sure key is allowed */ 483 if (key_blob == NULL || key_bloblen != bloblen || 484 timingsafe_bcmp(key_blob, blob, key_bloblen)) 485 return (0); 486 return (1); 487 } 488 489 static void 490 monitor_reset_key_state(void) 491 { 492 /* reset state */ 493 free(key_blob); 494 free(hostbased_cuser); 495 free(hostbased_chost); 496 sshauthopt_free(key_opts); 497 key_blob = NULL; 498 key_bloblen = 0; 499 key_blobtype = MM_NOKEY; 500 key_opts = NULL; 501 hostbased_cuser = NULL; 502 hostbased_chost = NULL; 503 } 504 505 #ifdef WITH_OPENSSL 506 int 507 mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m) 508 { 509 DH *dh; 510 const BIGNUM *dh_p, *dh_g; 511 int r; 512 u_int min, want, max; 513 514 if ((r = sshbuf_get_u32(m, &min)) != 0 || 515 (r = sshbuf_get_u32(m, &want)) != 0 || 516 (r = sshbuf_get_u32(m, &max)) != 0) 517 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 518 519 debug3("%s: got parameters: %d %d %d", 520 __func__, min, want, max); 521 /* We need to check here, too, in case the child got corrupted */ 522 if (max < min || want < min || max < want) 523 fatal("%s: bad parameters: %d %d %d", 524 __func__, min, want, max); 525 526 sshbuf_reset(m); 527 528 dh = choose_dh(min, want, max); 529 if (dh == NULL) { 530 if ((r = sshbuf_put_u8(m, 0)) != 0) 531 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 532 return (0); 533 } else { 534 /* Send first bignum */ 535 DH_get0_pqg(dh, &dh_p, NULL, &dh_g); 536 if ((r = sshbuf_put_u8(m, 1)) != 0 || 537 (r = sshbuf_put_bignum2(m, dh_p)) != 0 || 538 (r = sshbuf_put_bignum2(m, dh_g)) != 0) 539 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 540 541 DH_free(dh); 542 } 543 mm_request_send(sock, MONITOR_ANS_MODULI, m); 544 return (0); 545 } 546 #endif 547 548 int 549 mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m) 550 { 551 extern int auth_sock; /* XXX move to state struct? */ 552 struct sshkey *key; 553 struct sshbuf *sigbuf = NULL; 554 u_char *p = NULL, *signature = NULL; 555 char *alg = NULL; 556 size_t datlen, siglen, alglen; 557 int r, is_proof = 0; 558 u_int keyid, compat; 559 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 560 561 debug3("%s", __func__); 562 563 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 564 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 565 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0 || 566 (r = sshbuf_get_u32(m, &compat)) != 0) 567 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 568 if (keyid > INT_MAX) 569 fatal("%s: invalid key ID", __func__); 570 571 /* 572 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 573 * SHA384 (48 bytes) and SHA512 (64 bytes). 574 * 575 * Otherwise, verify the signature request is for a hostkey 576 * proof. 577 * 578 * XXX perform similar check for KEX signature requests too? 579 * it's not trivial, since what is signed is the hash, rather 580 * than the full kex structure... 581 */ 582 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 583 /* 584 * Construct expected hostkey proof and compare it to what 585 * the client sent us. 586 */ 587 if (session_id2_len == 0) /* hostkeys is never first */ 588 fatal("%s: bad data length: %zu", __func__, datlen); 589 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 590 fatal("%s: no hostkey for index %d", __func__, keyid); 591 if ((sigbuf = sshbuf_new()) == NULL) 592 fatal("%s: sshbuf_new", __func__); 593 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 594 (r = sshbuf_put_string(sigbuf, session_id2, 595 session_id2_len)) != 0 || 596 (r = sshkey_puts(key, sigbuf)) != 0) 597 fatal("%s: couldn't prepare private key " 598 "proof buffer: %s", __func__, ssh_err(r)); 599 if (datlen != sshbuf_len(sigbuf) || 600 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 601 fatal("%s: bad data length: %zu, hostkey proof len %zu", 602 __func__, datlen, sshbuf_len(sigbuf)); 603 sshbuf_free(sigbuf); 604 is_proof = 1; 605 } 606 607 /* save session id, it will be passed on the first call */ 608 if (session_id2_len == 0) { 609 session_id2_len = datlen; 610 session_id2 = xmalloc(session_id2_len); 611 memcpy(session_id2, p, session_id2_len); 612 } 613 614 if ((key = get_hostkey_by_index(keyid)) != NULL) { 615 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 616 options.sk_provider, NULL, compat)) != 0) 617 fatal("%s: sshkey_sign failed: %s", 618 __func__, ssh_err(r)); 619 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 620 auth_sock > 0) { 621 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 622 p, datlen, alg, compat)) != 0) { 623 fatal("%s: ssh_agent_sign failed: %s", 624 __func__, ssh_err(r)); 625 } 626 } else 627 fatal("%s: no hostkey from index %d", __func__, keyid); 628 629 debug3("%s: %s signature %p(%zu)", __func__, 630 is_proof ? "hostkey proof" : "KEX", signature, siglen); 631 632 sshbuf_reset(m); 633 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 634 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 635 636 free(alg); 637 free(p); 638 free(signature); 639 640 mm_request_send(sock, MONITOR_ANS_SIGN, m); 641 642 /* Turn on permissions for getpwnam */ 643 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 644 645 return (0); 646 } 647 648 /* Retrieves the password entry and also checks if the user is permitted */ 649 650 int 651 mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m) 652 { 653 char *username; 654 struct passwd *pwent; 655 int r, allowed = 0; 656 u_int i; 657 658 debug3("%s", __func__); 659 660 if (authctxt->attempt++ != 0) 661 fatal("%s: multiple attempts for getpwnam", __func__); 662 663 if ((r = sshbuf_get_cstring(m, &username, NULL)) != 0) 664 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 665 666 pwent = getpwnamallow(ssh, username); 667 668 authctxt->user = xstrdup(username); 669 setproctitle("%s [priv]", pwent ? username : "unknown"); 670 free(username); 671 672 sshbuf_reset(m); 673 674 if (pwent == NULL) { 675 if ((r = sshbuf_put_u8(m, 0)) != 0) 676 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 677 authctxt->pw = fakepw(); 678 goto out; 679 } 680 681 allowed = 1; 682 authctxt->pw = pwent; 683 authctxt->valid = 1; 684 685 /* XXX don't sent pwent to unpriv; send fake class/dir/shell too */ 686 if ((r = sshbuf_put_u8(m, 1)) != 0 || 687 (r = sshbuf_put_string(m, pwent, sizeof(*pwent))) != 0 || 688 (r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || 689 (r = sshbuf_put_cstring(m, "*")) != 0 || 690 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 || 691 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 || 692 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 || 693 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0) 694 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 695 696 out: 697 ssh_packet_set_log_preamble(ssh, "%suser %s", 698 authctxt->valid ? "authenticating" : "invalid ", authctxt->user); 699 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0) 700 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 701 702 #define M_CP_STROPT(x) do { \ 703 if (options.x != NULL) { \ 704 if ((r = sshbuf_put_cstring(m, options.x)) != 0) \ 705 fatal("%s: buffer error: %s", \ 706 __func__, ssh_err(r)); \ 707 } \ 708 } while (0) 709 #define M_CP_STRARRAYOPT(x, nx) do { \ 710 for (i = 0; i < options.nx; i++) { \ 711 if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \ 712 fatal("%s: buffer error: %s", \ 713 __func__, ssh_err(r)); \ 714 } \ 715 } while (0) 716 /* See comment in servconf.h */ 717 COPY_MATCH_STRING_OPTS(); 718 #undef M_CP_STROPT 719 #undef M_CP_STRARRAYOPT 720 721 /* Create valid auth method lists */ 722 if (auth2_setup_methods_lists(authctxt) != 0) { 723 /* 724 * The monitor will continue long enough to let the child 725 * run to it's packet_disconnect(), but it must not allow any 726 * authentication to succeed. 727 */ 728 debug("%s: no valid authentication method lists", __func__); 729 } 730 731 debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed); 732 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 733 734 /* Allow service/style information on the auth context */ 735 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 736 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 737 738 return (0); 739 } 740 741 int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m) 742 { 743 char *banner; 744 int r; 745 746 sshbuf_reset(m); 747 banner = auth2_read_banner(); 748 if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0) 749 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 750 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 751 free(banner); 752 753 return (0); 754 } 755 756 int 757 mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m) 758 { 759 int r; 760 761 monitor_permit_authentications(1); 762 763 if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 || 764 (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0) 765 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 766 debug3("%s: service=%s, style=%s", 767 __func__, authctxt->service, authctxt->style); 768 769 if (strlen(authctxt->style) == 0) { 770 free(authctxt->style); 771 authctxt->style = NULL; 772 } 773 774 return (0); 775 } 776 777 int 778 mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m) 779 { 780 static int call_count; 781 char *passwd; 782 int r, authenticated; 783 size_t plen; 784 785 if (!options.password_authentication) 786 fatal("%s: password authentication not enabled", __func__); 787 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0) 788 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 789 /* Only authenticate if the context is valid */ 790 authenticated = options.password_authentication && 791 auth_password(ssh, passwd); 792 freezero(passwd, plen); 793 794 sshbuf_reset(m); 795 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 796 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 797 798 debug3("%s: sending result %d", __func__, authenticated); 799 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 800 801 call_count++; 802 if (plen == 0 && call_count == 1) 803 auth_method = "none"; 804 else 805 auth_method = "password"; 806 807 /* Causes monitor loop to terminate if authenticated */ 808 return (authenticated); 809 } 810 811 int 812 mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m) 813 { 814 char *name, *infotxt; 815 u_int numprompts, *echo_on, success; 816 char **prompts; 817 int r; 818 819 if (!options.kbd_interactive_authentication) 820 fatal("%s: kbd-int authentication not enabled", __func__); 821 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 822 &prompts, &echo_on) < 0 ? 0 : 1; 823 824 sshbuf_reset(m); 825 if ((r = sshbuf_put_u32(m, success)) != 0) 826 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 827 if (success) { 828 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0) 829 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 830 } 831 832 debug3("%s: sending challenge success: %u", __func__, success); 833 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 834 835 if (success) { 836 free(name); 837 free(infotxt); 838 free(prompts); 839 free(echo_on); 840 } 841 842 return (0); 843 } 844 845 int 846 mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m) 847 { 848 char *response; 849 int r, authok; 850 851 if (!options.kbd_interactive_authentication) 852 fatal("%s: kbd-int authentication not enabled", __func__); 853 if (authctxt->as == NULL) 854 fatal("%s: no bsd auth session", __func__); 855 856 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 857 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 858 authok = options.challenge_response_authentication && 859 auth_userresponse(authctxt->as, response, 0); 860 authctxt->as = NULL; 861 debug3("%s: <%s> = <%d>", __func__, response, authok); 862 free(response); 863 864 sshbuf_reset(m); 865 if ((r = sshbuf_put_u32(m, authok)) != 0) 866 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 867 868 debug3("%s: sending authenticated: %d", __func__, authok); 869 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 870 871 auth_method = "keyboard-interactive"; 872 auth_submethod = "bsdauth"; 873 874 return (authok != 0); 875 } 876 877 /* 878 * Check that the key type appears in the supplied pattern list, ignoring 879 * mismatches in the signature algorithm. (Signature algorithm checks are 880 * performed in the unprivileged authentication code). 881 * Returns 1 on success, 0 otherwise. 882 */ 883 static int 884 key_base_type_match(const char *method, const struct sshkey *key, 885 const char *list) 886 { 887 char *s, *l, *ol = xstrdup(list); 888 int found = 0; 889 890 l = ol; 891 for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) { 892 if (sshkey_type_from_name(s) == key->type) { 893 found = 1; 894 break; 895 } 896 } 897 if (!found) { 898 error("%s key type %s is not in permitted list %s", method, 899 sshkey_ssh_name(key), list); 900 } 901 902 free(ol); 903 return found; 904 } 905 906 int 907 mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m) 908 { 909 struct sshkey *key = NULL; 910 char *cuser, *chost; 911 u_int pubkey_auth_attempt; 912 enum mm_keytype type = 0; 913 int r, allowed = 0; 914 struct sshauthopt *opts = NULL; 915 916 debug3("%s entering", __func__); 917 if ((r = sshbuf_get_u32(m, &type)) != 0 || 918 (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 || 919 (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 || 920 (r = sshkey_froms(m, &key)) != 0 || 921 (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0) 922 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 923 924 debug3("%s: key_from_blob: %p", __func__, key); 925 926 if (key != NULL && authctxt->valid) { 927 /* These should not make it past the privsep child */ 928 if (sshkey_type_plain(key->type) == KEY_RSA && 929 (datafellows & SSH_BUG_RSASIGMD5) != 0) 930 fatal("%s: passed a SSH_BUG_RSASIGMD5 key", __func__); 931 932 switch (type) { 933 case MM_USERKEY: 934 auth_method = "publickey"; 935 if (!options.pubkey_authentication) 936 break; 937 if (auth2_key_already_used(authctxt, key)) 938 break; 939 if (!key_base_type_match(auth_method, key, 940 options.pubkey_key_types)) 941 break; 942 allowed = user_key_allowed(ssh, authctxt->pw, key, 943 pubkey_auth_attempt, &opts); 944 break; 945 case MM_HOSTKEY: 946 auth_method = "hostbased"; 947 if (!options.hostbased_authentication) 948 break; 949 if (auth2_key_already_used(authctxt, key)) 950 break; 951 if (!key_base_type_match(auth_method, key, 952 options.hostbased_key_types)) 953 break; 954 allowed = hostbased_key_allowed(ssh, authctxt->pw, 955 cuser, chost, key); 956 auth2_record_info(authctxt, 957 "client user \"%.100s\", client host \"%.100s\"", 958 cuser, chost); 959 break; 960 default: 961 fatal("%s: unknown key type %d", __func__, type); 962 break; 963 } 964 } 965 966 debug3("%s: %s authentication%s: %s key is %s", __func__, 967 auth_method, pubkey_auth_attempt ? "" : " test", 968 (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key), 969 allowed ? "allowed" : "not allowed"); 970 971 auth2_record_key(authctxt, 0, key); 972 973 /* clear temporarily storage (used by verify) */ 974 monitor_reset_key_state(); 975 976 if (allowed) { 977 /* Save temporarily for comparison in verify */ 978 if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0) 979 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 980 key_blobtype = type; 981 key_opts = opts; 982 hostbased_cuser = cuser; 983 hostbased_chost = chost; 984 } else { 985 /* Log failed attempt */ 986 auth_log(ssh, 0, 0, auth_method, NULL); 987 free(cuser); 988 free(chost); 989 } 990 sshkey_free(key); 991 992 sshbuf_reset(m); 993 if ((r = sshbuf_put_u32(m, allowed)) != 0) 994 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 995 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0) 996 fatal("%s: sshauthopt_serialise: %s", __func__, ssh_err(r)); 997 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 998 999 if (!allowed) 1000 sshauthopt_free(opts); 1001 1002 return (0); 1003 } 1004 1005 static int 1006 monitor_valid_userblob(const u_char *data, u_int datalen) 1007 { 1008 struct sshbuf *b; 1009 const u_char *p; 1010 char *userstyle, *cp; 1011 size_t len; 1012 u_char type; 1013 int r, fail = 0; 1014 1015 if ((b = sshbuf_from(data, datalen)) == NULL) 1016 fatal("%s: sshbuf_from", __func__); 1017 1018 if (datafellows & SSH_OLD_SESSIONID) { 1019 p = sshbuf_ptr(b); 1020 len = sshbuf_len(b); 1021 if ((session_id2 == NULL) || 1022 (len < session_id2_len) || 1023 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1024 fail++; 1025 if ((r = sshbuf_consume(b, session_id2_len)) != 0) 1026 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1027 } else { 1028 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1029 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1030 if ((session_id2 == NULL) || 1031 (len != session_id2_len) || 1032 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1033 fail++; 1034 } 1035 if ((r = sshbuf_get_u8(b, &type)) != 0) 1036 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1037 if (type != SSH2_MSG_USERAUTH_REQUEST) 1038 fail++; 1039 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1040 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1041 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1042 authctxt->style ? ":" : "", 1043 authctxt->style ? authctxt->style : ""); 1044 if (strcmp(userstyle, cp) != 0) { 1045 logit("wrong user name passed to monitor: " 1046 "expected %s != %.100s", userstyle, cp); 1047 fail++; 1048 } 1049 free(userstyle); 1050 free(cp); 1051 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1052 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1053 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1054 if (strcmp("publickey", cp) != 0) 1055 fail++; 1056 free(cp); 1057 if ((r = sshbuf_get_u8(b, &type)) != 0) 1058 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1059 if (type == 0) 1060 fail++; 1061 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1062 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1063 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1064 if (sshbuf_len(b) != 0) 1065 fail++; 1066 sshbuf_free(b); 1067 return (fail == 0); 1068 } 1069 1070 static int 1071 monitor_valid_hostbasedblob(const u_char *data, u_int datalen, 1072 const char *cuser, const char *chost) 1073 { 1074 struct sshbuf *b; 1075 const u_char *p; 1076 char *cp, *userstyle; 1077 size_t len; 1078 int r, fail = 0; 1079 u_char type; 1080 1081 if ((b = sshbuf_from(data, datalen)) == NULL) 1082 fatal("%s: sshbuf_new", __func__); 1083 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1084 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1085 1086 if ((session_id2 == NULL) || 1087 (len != session_id2_len) || 1088 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1089 fail++; 1090 1091 if ((r = sshbuf_get_u8(b, &type)) != 0) 1092 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1093 if (type != SSH2_MSG_USERAUTH_REQUEST) 1094 fail++; 1095 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1096 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1097 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1098 authctxt->style ? ":" : "", 1099 authctxt->style ? authctxt->style : ""); 1100 if (strcmp(userstyle, cp) != 0) { 1101 logit("wrong user name passed to monitor: " 1102 "expected %s != %.100s", userstyle, cp); 1103 fail++; 1104 } 1105 free(userstyle); 1106 free(cp); 1107 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1108 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1109 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1110 if (strcmp(cp, "hostbased") != 0) 1111 fail++; 1112 free(cp); 1113 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1114 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1115 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1116 1117 /* verify client host, strip trailing dot if necessary */ 1118 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1119 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1120 if (((len = strlen(cp)) > 0) && cp[len - 1] == '.') 1121 cp[len - 1] = '\0'; 1122 if (strcmp(cp, chost) != 0) 1123 fail++; 1124 free(cp); 1125 1126 /* verify client user */ 1127 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1128 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1129 if (strcmp(cp, cuser) != 0) 1130 fail++; 1131 free(cp); 1132 1133 if (sshbuf_len(b) != 0) 1134 fail++; 1135 sshbuf_free(b); 1136 return (fail == 0); 1137 } 1138 1139 int 1140 mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m) 1141 { 1142 struct sshkey *key; 1143 const u_char *signature, *data, *blob; 1144 char *sigalg = NULL, *fp = NULL; 1145 size_t signaturelen, datalen, bloblen; 1146 int r, ret, req_presence = 0, valid_data = 0, encoded_ret; 1147 struct sshkey_sig_details *sig_details = NULL; 1148 1149 if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 || 1150 (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 || 1151 (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 || 1152 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0) 1153 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1154 1155 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1156 !monitor_allowed_key(blob, bloblen)) 1157 fatal("%s: bad key, not previously allowed", __func__); 1158 1159 /* Empty signature algorithm means NULL. */ 1160 if (*sigalg == '\0') { 1161 free(sigalg); 1162 sigalg = NULL; 1163 } 1164 1165 /* XXX use sshkey_froms here; need to change key_blob, etc. */ 1166 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0) 1167 fatal("%s: bad public key blob: %s", __func__, ssh_err(r)); 1168 1169 switch (key_blobtype) { 1170 case MM_USERKEY: 1171 valid_data = monitor_valid_userblob(data, datalen); 1172 auth_method = "publickey"; 1173 break; 1174 case MM_HOSTKEY: 1175 valid_data = monitor_valid_hostbasedblob(data, datalen, 1176 hostbased_cuser, hostbased_chost); 1177 auth_method = "hostbased"; 1178 break; 1179 default: 1180 valid_data = 0; 1181 break; 1182 } 1183 if (!valid_data) 1184 fatal("%s: bad signature data blob", __func__); 1185 1186 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 1187 SSH_FP_DEFAULT)) == NULL) 1188 fatal("%s: sshkey_fingerprint failed", __func__); 1189 1190 ret = sshkey_verify(key, signature, signaturelen, data, datalen, 1191 sigalg, ssh->compat, &sig_details); 1192 debug3("%s: %s %p signature %s%s%s", __func__, auth_method, key, 1193 (ret == 0) ? "verified" : "unverified", 1194 (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : ""); 1195 1196 if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) { 1197 req_presence = (options.pubkey_auth_options & 1198 PUBKEYAUTH_TOUCH_REQUIRED) || 1199 !key_opts->no_require_user_presence; 1200 if (req_presence && 1201 (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) { 1202 error("public key %s %s signature for %s%s from %.128s " 1203 "port %d rejected: user presence " 1204 "(authenticator touch) requirement not met ", 1205 sshkey_type(key), fp, 1206 authctxt->valid ? "" : "invalid user ", 1207 authctxt->user, ssh_remote_ipaddr(ssh), 1208 ssh_remote_port(ssh)); 1209 ret = SSH_ERR_SIGNATURE_INVALID; 1210 } 1211 } 1212 auth2_record_key(authctxt, ret == 0, key); 1213 1214 if (key_blobtype == MM_USERKEY) 1215 auth_activate_options(ssh, key_opts); 1216 monitor_reset_key_state(); 1217 1218 sshbuf_reset(m); 1219 1220 /* encode ret != 0 as positive integer, since we're sending u32 */ 1221 encoded_ret = (ret != 0); 1222 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 || 1223 (r = sshbuf_put_u8(m, sig_details != NULL)) != 0) 1224 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1225 if (sig_details != NULL) { 1226 if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 || 1227 (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0) 1228 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1229 } 1230 sshkey_sig_details_free(sig_details); 1231 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1232 1233 free(sigalg); 1234 free(fp); 1235 sshkey_free(key); 1236 1237 return ret == 0; 1238 } 1239 1240 static void 1241 mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw) 1242 { 1243 socklen_t fromlen; 1244 struct sockaddr_storage from; 1245 1246 /* 1247 * Get IP address of client. If the connection is not a socket, let 1248 * the address be 0.0.0.0. 1249 */ 1250 memset(&from, 0, sizeof(from)); 1251 fromlen = sizeof(from); 1252 if (ssh_packet_connection_is_on_socket(ssh)) { 1253 if (getpeername(ssh_packet_get_connection_in(ssh), 1254 (struct sockaddr *)&from, &fromlen) == -1) { 1255 debug("getpeername: %.100s", strerror(errno)); 1256 cleanup_exit(255); 1257 } 1258 } 1259 /* Record that there was a login on that tty from the remote host. */ 1260 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1261 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1262 (struct sockaddr *)&from, fromlen); 1263 } 1264 1265 static void 1266 mm_session_close(Session *s) 1267 { 1268 debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid); 1269 if (s->ttyfd != -1) { 1270 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd); 1271 session_pty_cleanup2(s); 1272 } 1273 session_unused(s->self); 1274 } 1275 1276 int 1277 mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m) 1278 { 1279 extern struct monitor *pmonitor; 1280 Session *s; 1281 int r, res, fd0; 1282 1283 debug3("%s entering", __func__); 1284 1285 sshbuf_reset(m); 1286 s = session_new(); 1287 if (s == NULL) 1288 goto error; 1289 s->authctxt = authctxt; 1290 s->pw = authctxt->pw; 1291 s->pid = pmonitor->m_pid; 1292 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1293 if (res == 0) 1294 goto error; 1295 pty_setowner(authctxt->pw, s->tty); 1296 1297 if ((r = sshbuf_put_u32(m, 1)) != 0 || 1298 (r = sshbuf_put_cstring(m, s->tty)) != 0) 1299 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1300 1301 /* We need to trick ttyslot */ 1302 if (dup2(s->ttyfd, 0) == -1) 1303 fatal("%s: dup2", __func__); 1304 1305 mm_record_login(ssh, s, authctxt->pw); 1306 1307 /* Now we can close the file descriptor again */ 1308 close(0); 1309 1310 /* send messages generated by record_login */ 1311 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0) 1312 fatal("%s: put login message: %s", __func__, ssh_err(r)); 1313 sshbuf_reset(loginmsg); 1314 1315 mm_request_send(sock, MONITOR_ANS_PTY, m); 1316 1317 if (mm_send_fd(sock, s->ptyfd) == -1 || 1318 mm_send_fd(sock, s->ttyfd) == -1) 1319 fatal("%s: send fds failed", __func__); 1320 1321 /* make sure nothing uses fd 0 */ 1322 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1323 fatal("%s: open(/dev/null): %s", __func__, strerror(errno)); 1324 if (fd0 != 0) 1325 error("%s: fd0 %d != 0", __func__, fd0); 1326 1327 /* slave side of pty is not needed */ 1328 close(s->ttyfd); 1329 s->ttyfd = s->ptyfd; 1330 /* no need to dup() because nobody closes ptyfd */ 1331 s->ptymaster = s->ptyfd; 1332 1333 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd); 1334 1335 return (0); 1336 1337 error: 1338 if (s != NULL) 1339 mm_session_close(s); 1340 if ((r = sshbuf_put_u32(m, 0)) != 0) 1341 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1342 mm_request_send(sock, MONITOR_ANS_PTY, m); 1343 return (0); 1344 } 1345 1346 int 1347 mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m) 1348 { 1349 Session *s; 1350 char *tty; 1351 int r; 1352 1353 debug3("%s entering", __func__); 1354 1355 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0) 1356 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1357 if ((s = session_by_tty(tty)) != NULL) 1358 mm_session_close(s); 1359 sshbuf_reset(m); 1360 free(tty); 1361 return (0); 1362 } 1363 1364 int 1365 mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req) 1366 { 1367 extern struct monitor *pmonitor; 1368 int res, status; 1369 1370 debug3("%s: tearing down sessions", __func__); 1371 1372 /* The child is terminating */ 1373 session_destroy_all(ssh, &mm_session_close); 1374 1375 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1376 if (errno != EINTR) 1377 exit(1); 1378 1379 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1380 1381 /* Terminate process */ 1382 exit(res); 1383 } 1384 1385 void 1386 monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor) 1387 { 1388 ssh_clear_newkeys(ssh, MODE_IN); 1389 ssh_clear_newkeys(ssh, MODE_OUT); 1390 sshbuf_free(child_state); 1391 child_state = NULL; 1392 } 1393 1394 void 1395 monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor) 1396 { 1397 struct kex *kex; 1398 int r; 1399 1400 debug3("%s: packet_set_state", __func__); 1401 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1402 fatal("%s: packet_set_state: %s", __func__, ssh_err(r)); 1403 sshbuf_free(child_state); 1404 child_state = NULL; 1405 1406 if ((kex = ssh->kex) != NULL) { 1407 /* XXX set callbacks */ 1408 #ifdef WITH_OPENSSL 1409 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server; 1410 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server; 1411 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server; 1412 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server; 1413 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server; 1414 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1415 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1416 kex->kex[KEX_ECDH_SHA2] = kex_gen_server; 1417 #endif 1418 kex->kex[KEX_C25519_SHA256] = kex_gen_server; 1419 kex->kex[KEX_KEM_SNTRUP4591761X25519_SHA512] = kex_gen_server; 1420 kex->load_host_public_key=&get_hostkey_public_by_type; 1421 kex->load_host_private_key=&get_hostkey_private_by_type; 1422 kex->host_key_index=&get_hostkey_index; 1423 kex->sign = sshd_hostkey_sign; 1424 } 1425 } 1426 1427 /* This function requires careful sanity checking */ 1428 1429 void 1430 mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor) 1431 { 1432 debug3("%s: Waiting for new keys", __func__); 1433 1434 if ((child_state = sshbuf_new()) == NULL) 1435 fatal("%s: sshbuf_new failed", __func__); 1436 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1437 child_state); 1438 debug3("%s: GOT new keys", __func__); 1439 } 1440 1441 1442 /* XXX */ 1443 1444 #define FD_CLOSEONEXEC(x) do { \ 1445 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1446 fatal("fcntl(%d, F_SETFD)", x); \ 1447 } while (0) 1448 1449 static void 1450 monitor_openfds(struct monitor *mon, int do_logfds) 1451 { 1452 int pair[2]; 1453 #ifdef SO_ZEROIZE 1454 int on = 1; 1455 #endif 1456 1457 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1458 fatal("%s: socketpair: %s", __func__, strerror(errno)); 1459 #ifdef SO_ZEROIZE 1460 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1461 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno)); 1462 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1463 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno)); 1464 #endif 1465 FD_CLOSEONEXEC(pair[0]); 1466 FD_CLOSEONEXEC(pair[1]); 1467 mon->m_recvfd = pair[0]; 1468 mon->m_sendfd = pair[1]; 1469 1470 if (do_logfds) { 1471 if (pipe(pair) == -1) 1472 fatal("%s: pipe: %s", __func__, strerror(errno)); 1473 FD_CLOSEONEXEC(pair[0]); 1474 FD_CLOSEONEXEC(pair[1]); 1475 mon->m_log_recvfd = pair[0]; 1476 mon->m_log_sendfd = pair[1]; 1477 } else 1478 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1479 } 1480 1481 #define MM_MEMSIZE 65536 1482 1483 struct monitor * 1484 monitor_init(void) 1485 { 1486 struct monitor *mon; 1487 1488 mon = xcalloc(1, sizeof(*mon)); 1489 monitor_openfds(mon, 1); 1490 1491 return mon; 1492 } 1493 1494 void 1495 monitor_reinit(struct monitor *mon) 1496 { 1497 monitor_openfds(mon, 0); 1498 } 1499 1500 #ifdef GSSAPI 1501 int 1502 mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1503 { 1504 gss_OID_desc goid; 1505 OM_uint32 major; 1506 size_t len; 1507 u_char *p; 1508 int r; 1509 1510 if (!options.gss_authentication) 1511 fatal("%s: GSSAPI authentication not enabled", __func__); 1512 1513 if ((r = sshbuf_get_string(m, &p, &len)) != 0) 1514 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1515 goid.elements = p; 1516 goid.length = len; 1517 1518 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1519 1520 free(goid.elements); 1521 1522 sshbuf_reset(m); 1523 if ((r = sshbuf_put_u32(m, major)) != 0) 1524 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1525 1526 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1527 1528 /* Now we have a context, enable the step */ 1529 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1530 1531 return (0); 1532 } 1533 1534 int 1535 mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1536 { 1537 gss_buffer_desc in; 1538 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1539 OM_uint32 major, minor; 1540 OM_uint32 flags = 0; /* GSI needs this */ 1541 int r; 1542 1543 if (!options.gss_authentication) 1544 fatal("%s: GSSAPI authentication not enabled", __func__); 1545 1546 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0) 1547 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1548 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1549 free(in.value); 1550 1551 sshbuf_reset(m); 1552 if ((r = sshbuf_put_u32(m, major)) != 0 || 1553 (r = sshbuf_put_string(m, out.value, out.length)) != 0 || 1554 (r = sshbuf_put_u32(m, flags)) != 0) 1555 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1556 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1557 1558 gss_release_buffer(&minor, &out); 1559 1560 if (major == GSS_S_COMPLETE) { 1561 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1562 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1563 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1564 } 1565 return (0); 1566 } 1567 1568 int 1569 mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m) 1570 { 1571 gss_buffer_desc gssbuf, mic; 1572 OM_uint32 ret; 1573 int r; 1574 1575 if (!options.gss_authentication) 1576 fatal("%s: GSSAPI authentication not enabled", __func__); 1577 1578 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 || 1579 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0) 1580 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1581 1582 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1583 1584 free(gssbuf.value); 1585 free(mic.value); 1586 1587 sshbuf_reset(m); 1588 if ((r = sshbuf_put_u32(m, ret)) != 0) 1589 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1590 1591 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1592 1593 if (!GSS_ERROR(ret)) 1594 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1595 1596 return (0); 1597 } 1598 1599 int 1600 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m) 1601 { 1602 int r, authenticated; 1603 const char *displayname; 1604 1605 if (!options.gss_authentication) 1606 fatal("%s: GSSAPI authentication not enabled", __func__); 1607 1608 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1609 1610 sshbuf_reset(m); 1611 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 1612 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1613 1614 debug3("%s: sending result %d", __func__, authenticated); 1615 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1616 1617 auth_method = "gssapi-with-mic"; 1618 1619 if ((displayname = ssh_gssapi_displayname()) != NULL) 1620 auth2_record_info(authctxt, "%s", displayname); 1621 1622 /* Monitor loop will terminate if authenticated */ 1623 return (authenticated); 1624 } 1625 #endif /* GSSAPI */ 1626 1627