1 /* $OpenBSD: monitor.c,v 1.220 2021/01/22 02:44:58 dtucker 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_f("method %s: partial", auth_method); 265 authenticated = 0; 266 partial = 1; 267 } 268 } 269 270 if (authenticated) { 271 if (!(ent->flags & MON_AUTHDECIDE)) 272 fatal_f("unexpected authentication from %d", 273 ent->type); 274 if (authctxt->pw->pw_uid == 0 && 275 !auth_root_allowed(ssh, auth_method)) 276 authenticated = 0; 277 } 278 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 279 auth_log(ssh, authenticated, partial, 280 auth_method, auth_submethod); 281 if (!partial && !authenticated) 282 authctxt->failures++; 283 if (authenticated || partial) { 284 auth2_update_session_info(authctxt, 285 auth_method, auth_submethod); 286 } 287 } 288 } 289 290 if (!authctxt->valid) 291 fatal_f("authenticated invalid user"); 292 if (strcmp(auth_method, "unknown") == 0) 293 fatal_f("authentication method name unknown"); 294 295 debug_f("user %s authenticated by privileged process", authctxt->user); 296 ssh->authctxt = NULL; 297 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 298 299 mm_get_keystate(ssh, pmonitor); 300 301 /* Drain any buffered messages from the child */ 302 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 303 ; 304 305 if (pmonitor->m_recvfd >= 0) 306 close(pmonitor->m_recvfd); 307 if (pmonitor->m_log_sendfd >= 0) 308 close(pmonitor->m_log_sendfd); 309 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 310 } 311 312 static void 313 monitor_set_child_handler(pid_t pid) 314 { 315 monitor_child_pid = pid; 316 } 317 318 static void 319 monitor_child_handler(int sig) 320 { 321 kill(monitor_child_pid, sig); 322 } 323 324 void 325 monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor) 326 { 327 close(pmonitor->m_recvfd); 328 pmonitor->m_recvfd = -1; 329 330 monitor_set_child_handler(pmonitor->m_pid); 331 ssh_signal(SIGHUP, &monitor_child_handler); 332 ssh_signal(SIGTERM, &monitor_child_handler); 333 ssh_signal(SIGINT, &monitor_child_handler); 334 335 mon_dispatch = mon_dispatch_postauth20; 336 337 /* Permit requests for moduli and signatures */ 338 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 339 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 340 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 341 342 if (auth_opts->permit_pty_flag) { 343 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 344 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 345 } 346 347 for (;;) 348 monitor_read(ssh, pmonitor, mon_dispatch, NULL); 349 } 350 351 static int 352 monitor_read_log(struct monitor *pmonitor) 353 { 354 struct sshbuf *logmsg; 355 u_int len, level, line; 356 char *msg, *file, *func; 357 u_char *p; 358 int r; 359 360 if ((logmsg = sshbuf_new()) == NULL) 361 fatal_f("sshbuf_new"); 362 363 /* Read length */ 364 if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0) 365 fatal_fr(r, "reserve len"); 366 if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) { 367 if (errno == EPIPE) { 368 sshbuf_free(logmsg); 369 debug_f("child log fd closed"); 370 close(pmonitor->m_log_recvfd); 371 pmonitor->m_log_recvfd = -1; 372 return -1; 373 } 374 fatal_f("log fd read: %s", strerror(errno)); 375 } 376 if ((r = sshbuf_get_u32(logmsg, &len)) != 0) 377 fatal_fr(r, "parse len"); 378 if (len <= 4 || len > 8192) 379 fatal_f("invalid log message length %u", len); 380 381 /* Read severity, message */ 382 sshbuf_reset(logmsg); 383 if ((r = sshbuf_reserve(logmsg, len, &p)) != 0) 384 fatal_fr(r, "reserve msg"); 385 if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len) 386 fatal_f("log fd read: %s", strerror(errno)); 387 if ((r = sshbuf_get_cstring(logmsg, &file, NULL)) != 0 || 388 (r = sshbuf_get_cstring(logmsg, &func, NULL)) != 0 || 389 (r = sshbuf_get_u32(logmsg, &line)) != 0 || 390 (r = sshbuf_get_u32(logmsg, &level)) != 0 || 391 (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0) 392 fatal_fr(r, "parse"); 393 394 /* Log it */ 395 if (log_level_name(level) == NULL) 396 fatal_f("invalid log level %u (corrupted message?)", level); 397 sshlog(file, func, line, 0, level, NULL, "%s [preauth]", msg); 398 399 sshbuf_free(logmsg); 400 free(file); 401 free(func); 402 free(msg); 403 404 return 0; 405 } 406 407 static int 408 monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent, 409 struct mon_table **pent) 410 { 411 struct sshbuf *m; 412 int r, ret; 413 u_char type; 414 struct pollfd pfd[2]; 415 416 for (;;) { 417 memset(&pfd, 0, sizeof(pfd)); 418 pfd[0].fd = pmonitor->m_sendfd; 419 pfd[0].events = POLLIN; 420 pfd[1].fd = pmonitor->m_log_recvfd; 421 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 422 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 423 if (errno == EINTR || errno == EAGAIN) 424 continue; 425 fatal_f("poll: %s", strerror(errno)); 426 } 427 if (pfd[1].revents) { 428 /* 429 * Drain all log messages before processing next 430 * monitor request. 431 */ 432 monitor_read_log(pmonitor); 433 continue; 434 } 435 if (pfd[0].revents) 436 break; /* Continues below */ 437 } 438 439 if ((m = sshbuf_new()) == NULL) 440 fatal_f("sshbuf_new"); 441 442 mm_request_receive(pmonitor->m_sendfd, m); 443 if ((r = sshbuf_get_u8(m, &type)) != 0) 444 fatal_fr(r, "parse type"); 445 446 debug3_f("checking request %d", type); 447 448 while (ent->f != NULL) { 449 if (ent->type == type) 450 break; 451 ent++; 452 } 453 454 if (ent->f != NULL) { 455 if (!(ent->flags & MON_PERMIT)) 456 fatal_f("unpermitted request %d", type); 457 ret = (*ent->f)(ssh, pmonitor->m_sendfd, m); 458 sshbuf_free(m); 459 460 /* The child may use this request only once, disable it */ 461 if (ent->flags & MON_ONCE) { 462 debug2_f("%d used once, disabling now", type); 463 ent->flags &= ~MON_PERMIT; 464 } 465 466 if (pent != NULL) 467 *pent = ent; 468 469 return ret; 470 } 471 472 fatal_f("unsupported request: %d", 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_fr(r, "parse"); 518 519 debug3_f("got parameters: %d %d %d", min, want, max); 520 /* We need to check here, too, in case the child got corrupted */ 521 if (max < min || want < min || max < want) 522 fatal_f("bad parameters: %d %d %d", min, want, max); 523 524 sshbuf_reset(m); 525 526 dh = choose_dh(min, want, max); 527 if (dh == NULL) { 528 if ((r = sshbuf_put_u8(m, 0)) != 0) 529 fatal_fr(r, "assemble empty"); 530 return (0); 531 } else { 532 /* Send first bignum */ 533 DH_get0_pqg(dh, &dh_p, NULL, &dh_g); 534 if ((r = sshbuf_put_u8(m, 1)) != 0 || 535 (r = sshbuf_put_bignum2(m, dh_p)) != 0 || 536 (r = sshbuf_put_bignum2(m, dh_g)) != 0) 537 fatal_fr(r, "assemble"); 538 539 DH_free(dh); 540 } 541 mm_request_send(sock, MONITOR_ANS_MODULI, m); 542 return (0); 543 } 544 #endif 545 546 int 547 mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m) 548 { 549 extern int auth_sock; /* XXX move to state struct? */ 550 struct sshkey *key; 551 struct sshbuf *sigbuf = NULL; 552 u_char *p = NULL, *signature = NULL; 553 char *alg = NULL; 554 size_t datlen, siglen, alglen; 555 int r, is_proof = 0; 556 u_int keyid, compat; 557 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 558 559 debug3_f("entering"); 560 561 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 562 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 563 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0 || 564 (r = sshbuf_get_u32(m, &compat)) != 0) 565 fatal_fr(r, "parse"); 566 if (keyid > INT_MAX) 567 fatal_f("invalid key ID"); 568 569 /* 570 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 571 * SHA384 (48 bytes) and SHA512 (64 bytes). 572 * 573 * Otherwise, verify the signature request is for a hostkey 574 * proof. 575 * 576 * XXX perform similar check for KEX signature requests too? 577 * it's not trivial, since what is signed is the hash, rather 578 * than the full kex structure... 579 */ 580 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 581 /* 582 * Construct expected hostkey proof and compare it to what 583 * the client sent us. 584 */ 585 if (session_id2_len == 0) /* hostkeys is never first */ 586 fatal_f("bad data length: %zu", datlen); 587 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 588 fatal_f("no hostkey for index %d", keyid); 589 if ((sigbuf = sshbuf_new()) == NULL) 590 fatal_f("sshbuf_new"); 591 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 592 (r = sshbuf_put_string(sigbuf, session_id2, 593 session_id2_len)) != 0 || 594 (r = sshkey_puts(key, sigbuf)) != 0) 595 fatal_fr(r, "assemble private key proof"); 596 if (datlen != sshbuf_len(sigbuf) || 597 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 598 fatal_f("bad data length: %zu, hostkey proof len %zu", 599 datlen, sshbuf_len(sigbuf)); 600 sshbuf_free(sigbuf); 601 is_proof = 1; 602 } 603 604 /* save session id, it will be passed on the first call */ 605 if (session_id2_len == 0) { 606 session_id2_len = datlen; 607 session_id2 = xmalloc(session_id2_len); 608 memcpy(session_id2, p, session_id2_len); 609 } 610 611 if ((key = get_hostkey_by_index(keyid)) != NULL) { 612 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 613 options.sk_provider, NULL, compat)) != 0) 614 fatal_fr(r, "sign"); 615 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 616 auth_sock > 0) { 617 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 618 p, datlen, alg, compat)) != 0) 619 fatal_fr(r, "agent sign"); 620 } else 621 fatal_f("no hostkey from index %d", keyid); 622 623 debug3_f("%s signature %p(%zu)", is_proof ? "hostkey proof" : "KEX", 624 signature, siglen); 625 626 sshbuf_reset(m); 627 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 628 fatal_fr(r, "assemble"); 629 630 free(alg); 631 free(p); 632 free(signature); 633 634 mm_request_send(sock, MONITOR_ANS_SIGN, m); 635 636 /* Turn on permissions for getpwnam */ 637 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 638 639 return (0); 640 } 641 642 #define PUTPW(b, id) \ 643 do { \ 644 if ((r = sshbuf_put_string(b, \ 645 &pwent->id, sizeof(pwent->id))) != 0) \ 646 fatal_fr(r, "assemble %s", #id); \ 647 } while (0) 648 649 /* Retrieves the password entry and also checks if the user is permitted */ 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_f("entering"); 659 660 if (authctxt->attempt++ != 0) 661 fatal_f("multiple attempts for getpwnam"); 662 663 if ((r = sshbuf_get_cstring(m, &username, NULL)) != 0) 664 fatal_fr(r, "parse"); 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_fr(r, "assemble fakepw"); 677 authctxt->pw = fakepw(); 678 goto out; 679 } 680 681 allowed = 1; 682 authctxt->pw = pwent; 683 authctxt->valid = 1; 684 685 /* XXX send fake class/dir/shell, etc. */ 686 if ((r = sshbuf_put_u8(m, 1)) != 0) 687 fatal_fr(r, "assemble ok"); 688 PUTPW(m, pw_uid); 689 PUTPW(m, pw_gid); 690 PUTPW(m, pw_change); 691 PUTPW(m, pw_expire); 692 if ((r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || 693 (r = sshbuf_put_cstring(m, "*")) != 0 || 694 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 || 695 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 || 696 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 || 697 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0) 698 fatal_fr(r, "assemble pw"); 699 700 out: 701 ssh_packet_set_log_preamble(ssh, "%suser %s", 702 authctxt->valid ? "authenticating" : "invalid ", authctxt->user); 703 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0) 704 fatal_fr(r, "assemble options"); 705 706 #define M_CP_STROPT(x) do { \ 707 if (options.x != NULL && \ 708 (r = sshbuf_put_cstring(m, options.x)) != 0) \ 709 fatal_fr(r, "assemble %s", #x); \ 710 } while (0) 711 #define M_CP_STRARRAYOPT(x, nx) do { \ 712 for (i = 0; i < options.nx; i++) { \ 713 if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \ 714 fatal_fr(r, "assemble %s", #x); \ 715 } \ 716 } while (0) 717 /* See comment in servconf.h */ 718 COPY_MATCH_STRING_OPTS(); 719 #undef M_CP_STROPT 720 #undef M_CP_STRARRAYOPT 721 722 /* Create valid auth method lists */ 723 if (auth2_setup_methods_lists(authctxt) != 0) { 724 /* 725 * The monitor will continue long enough to let the child 726 * run to it's packet_disconnect(), but it must not allow any 727 * authentication to succeed. 728 */ 729 debug_f("no valid authentication method lists"); 730 } 731 732 debug3_f("sending MONITOR_ANS_PWNAM: %d", allowed); 733 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 734 735 /* Allow service/style information on the auth context */ 736 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 737 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 738 739 return (0); 740 } 741 742 int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m) 743 { 744 char *banner; 745 int r; 746 747 sshbuf_reset(m); 748 banner = auth2_read_banner(); 749 if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0) 750 fatal_fr(r, "assemble"); 751 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 752 free(banner); 753 754 return (0); 755 } 756 757 int 758 mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m) 759 { 760 int r; 761 762 monitor_permit_authentications(1); 763 764 if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 || 765 (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0) 766 fatal_fr(r, "parse"); 767 debug3_f("service=%s, style=%s", 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_f("password authentication not enabled"); 787 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0) 788 fatal_fr(r, "parse"); 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_fr(r, "assemble"); 797 798 debug3_f("sending result %d", 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_f("kbd-int authentication not enabled"); 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_fr(r, "assemble"); 827 if (success) { 828 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0) 829 fatal_fr(r, "assemble prompt"); 830 } 831 832 debug3_f("sending challenge success: %u", 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_f("kbd-int authentication not enabled"); 853 if (authctxt->as == NULL) 854 fatal_f("no bsd auth session"); 855 856 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 857 fatal_fr(r, "parse"); 858 authok = options.challenge_response_authentication && 859 auth_userresponse(authctxt->as, response, 0); 860 authctxt->as = NULL; 861 debug3_f("<%s> = <%d>", response, authok); 862 free(response); 863 864 sshbuf_reset(m); 865 if ((r = sshbuf_put_u32(m, authok)) != 0) 866 fatal_fr(r, "assemble"); 867 868 debug3_f("sending authenticated: %d", 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_f("entering"); 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_fr(r, "parse"); 923 924 debug3_f("key_from_blob: %p", 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_f("passed a SSH_BUG_RSASIGMD5 key"); 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_accepted_algos)) 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_f("unknown key type %d", type); 962 break; 963 } 964 } 965 966 debug3_f("%s authentication%s: %s key is %s", auth_method, 967 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_fr(r, "sshkey_to_blob"); 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_fr(r, "assemble"); 995 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0) 996 fatal_fr(r, "sshauthopt_serialise"); 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_f("sshbuf_from"); 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_fr(r, "consume"); 1027 } else { 1028 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1029 fatal_fr(r, "parse sessionid"); 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_fr(r, "parse type"); 1037 if (type != SSH2_MSG_USERAUTH_REQUEST) 1038 fail++; 1039 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1040 fatal_fr(r, "parse userstyle"); 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_fr(r, "parse method"); 1054 if (strcmp("publickey", cp) != 0) 1055 fail++; 1056 free(cp); 1057 if ((r = sshbuf_get_u8(b, &type)) != 0) 1058 fatal_fr(r, "parse pktype"); 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_fr(r, "parse pk"); 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_f("sshbuf_new"); 1083 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1084 fatal_fr(r, "parse sessionid"); 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_fr(r, "parse type"); 1093 if (type != SSH2_MSG_USERAUTH_REQUEST) 1094 fail++; 1095 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1096 fatal_fr(r, "parse userstyle"); 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_fr(r, "parse method"); 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_fr(r, "parse pk"); 1116 1117 /* verify client host, strip trailing dot if necessary */ 1118 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1119 fatal_fr(r, "parse host"); 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_fr(r, "parse ruser"); 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, req_verify = 0, valid_data = 0; 1147 int encoded_ret; 1148 struct sshkey_sig_details *sig_details = NULL; 1149 1150 if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 || 1151 (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 || 1152 (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 || 1153 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0) 1154 fatal_fr(r, "parse"); 1155 1156 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1157 !monitor_allowed_key(blob, bloblen)) 1158 fatal_f("bad key, not previously allowed"); 1159 1160 /* Empty signature algorithm means NULL. */ 1161 if (*sigalg == '\0') { 1162 free(sigalg); 1163 sigalg = NULL; 1164 } 1165 1166 /* XXX use sshkey_froms here; need to change key_blob, etc. */ 1167 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0) 1168 fatal_fr(r, "parse key"); 1169 1170 switch (key_blobtype) { 1171 case MM_USERKEY: 1172 valid_data = monitor_valid_userblob(data, datalen); 1173 auth_method = "publickey"; 1174 break; 1175 case MM_HOSTKEY: 1176 valid_data = monitor_valid_hostbasedblob(data, datalen, 1177 hostbased_cuser, hostbased_chost); 1178 auth_method = "hostbased"; 1179 break; 1180 default: 1181 valid_data = 0; 1182 break; 1183 } 1184 if (!valid_data) 1185 fatal_f("bad signature data blob"); 1186 1187 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 1188 SSH_FP_DEFAULT)) == NULL) 1189 fatal_f("sshkey_fingerprint failed"); 1190 1191 ret = sshkey_verify(key, signature, signaturelen, data, datalen, 1192 sigalg, ssh->compat, &sig_details); 1193 debug3_f("%s %p signature %s%s%s", auth_method, key, 1194 (ret == 0) ? "verified" : "unverified", 1195 (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : ""); 1196 1197 if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) { 1198 req_presence = (options.pubkey_auth_options & 1199 PUBKEYAUTH_TOUCH_REQUIRED) || 1200 !key_opts->no_require_user_presence; 1201 if (req_presence && 1202 (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) { 1203 error("public key %s %s signature for %s%s from %.128s " 1204 "port %d rejected: user presence " 1205 "(authenticator touch) requirement not met ", 1206 sshkey_type(key), fp, 1207 authctxt->valid ? "" : "invalid user ", 1208 authctxt->user, ssh_remote_ipaddr(ssh), 1209 ssh_remote_port(ssh)); 1210 ret = SSH_ERR_SIGNATURE_INVALID; 1211 } 1212 req_verify = (options.pubkey_auth_options & 1213 PUBKEYAUTH_VERIFY_REQUIRED) || key_opts->require_verify; 1214 if (req_verify && 1215 (sig_details->sk_flags & SSH_SK_USER_VERIFICATION_REQD) == 0) { 1216 error("public key %s %s signature for %s%s from %.128s " 1217 "port %d rejected: user verification requirement " 1218 "not met ", sshkey_type(key), fp, 1219 authctxt->valid ? "" : "invalid user ", 1220 authctxt->user, ssh_remote_ipaddr(ssh), 1221 ssh_remote_port(ssh)); 1222 ret = SSH_ERR_SIGNATURE_INVALID; 1223 } 1224 } 1225 auth2_record_key(authctxt, ret == 0, key); 1226 1227 if (key_blobtype == MM_USERKEY) 1228 auth_activate_options(ssh, key_opts); 1229 monitor_reset_key_state(); 1230 1231 sshbuf_reset(m); 1232 1233 /* encode ret != 0 as positive integer, since we're sending u32 */ 1234 encoded_ret = (ret != 0); 1235 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 || 1236 (r = sshbuf_put_u8(m, sig_details != NULL)) != 0) 1237 fatal_fr(r, "assemble"); 1238 if (sig_details != NULL) { 1239 if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 || 1240 (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0) 1241 fatal_fr(r, "assemble sk"); 1242 } 1243 sshkey_sig_details_free(sig_details); 1244 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1245 1246 free(sigalg); 1247 free(fp); 1248 sshkey_free(key); 1249 1250 return ret == 0; 1251 } 1252 1253 static void 1254 mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw) 1255 { 1256 socklen_t fromlen; 1257 struct sockaddr_storage from; 1258 1259 /* 1260 * Get IP address of client. If the connection is not a socket, let 1261 * the address be 0.0.0.0. 1262 */ 1263 memset(&from, 0, sizeof(from)); 1264 fromlen = sizeof(from); 1265 if (ssh_packet_connection_is_on_socket(ssh)) { 1266 if (getpeername(ssh_packet_get_connection_in(ssh), 1267 (struct sockaddr *)&from, &fromlen) == -1) { 1268 debug("getpeername: %.100s", strerror(errno)); 1269 cleanup_exit(255); 1270 } 1271 } 1272 /* Record that there was a login on that tty from the remote host. */ 1273 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1274 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1275 (struct sockaddr *)&from, fromlen); 1276 } 1277 1278 static void 1279 mm_session_close(Session *s) 1280 { 1281 debug3_f("session %d pid %ld", s->self, (long)s->pid); 1282 if (s->ttyfd != -1) { 1283 debug3_f("tty %s ptyfd %d", s->tty, s->ptyfd); 1284 session_pty_cleanup2(s); 1285 } 1286 session_unused(s->self); 1287 } 1288 1289 int 1290 mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m) 1291 { 1292 extern struct monitor *pmonitor; 1293 Session *s; 1294 int r, res, fd0; 1295 1296 debug3_f("entering"); 1297 1298 sshbuf_reset(m); 1299 s = session_new(); 1300 if (s == NULL) 1301 goto error; 1302 s->authctxt = authctxt; 1303 s->pw = authctxt->pw; 1304 s->pid = pmonitor->m_pid; 1305 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1306 if (res == 0) 1307 goto error; 1308 pty_setowner(authctxt->pw, s->tty); 1309 1310 if ((r = sshbuf_put_u32(m, 1)) != 0 || 1311 (r = sshbuf_put_cstring(m, s->tty)) != 0) 1312 fatal_fr(r, "assemble"); 1313 1314 /* We need to trick ttyslot */ 1315 if (dup2(s->ttyfd, 0) == -1) 1316 fatal_f("dup2"); 1317 1318 mm_record_login(ssh, s, authctxt->pw); 1319 1320 /* Now we can close the file descriptor again */ 1321 close(0); 1322 1323 /* send messages generated by record_login */ 1324 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0) 1325 fatal_fr(r, "assemble loginmsg"); 1326 sshbuf_reset(loginmsg); 1327 1328 mm_request_send(sock, MONITOR_ANS_PTY, m); 1329 1330 if (mm_send_fd(sock, s->ptyfd) == -1 || 1331 mm_send_fd(sock, s->ttyfd) == -1) 1332 fatal_f("send fds failed"); 1333 1334 /* make sure nothing uses fd 0 */ 1335 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1336 fatal_f("open(/dev/null): %s", strerror(errno)); 1337 if (fd0 != 0) 1338 error_f("fd0 %d != 0", fd0); 1339 1340 /* slave side of pty is not needed */ 1341 close(s->ttyfd); 1342 s->ttyfd = s->ptyfd; 1343 /* no need to dup() because nobody closes ptyfd */ 1344 s->ptymaster = s->ptyfd; 1345 1346 debug3_f("tty %s ptyfd %d", s->tty, s->ttyfd); 1347 1348 return (0); 1349 1350 error: 1351 if (s != NULL) 1352 mm_session_close(s); 1353 if ((r = sshbuf_put_u32(m, 0)) != 0) 1354 fatal_fr(r, "assemble 0"); 1355 mm_request_send(sock, MONITOR_ANS_PTY, m); 1356 return (0); 1357 } 1358 1359 int 1360 mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m) 1361 { 1362 Session *s; 1363 char *tty; 1364 int r; 1365 1366 debug3_f("entering"); 1367 1368 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0) 1369 fatal_fr(r, "parse tty"); 1370 if ((s = session_by_tty(tty)) != NULL) 1371 mm_session_close(s); 1372 sshbuf_reset(m); 1373 free(tty); 1374 return (0); 1375 } 1376 1377 int 1378 mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req) 1379 { 1380 extern struct monitor *pmonitor; 1381 int res, status; 1382 1383 debug3_f("tearing down sessions"); 1384 1385 /* The child is terminating */ 1386 session_destroy_all(ssh, &mm_session_close); 1387 1388 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1389 if (errno != EINTR) 1390 exit(1); 1391 1392 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1393 1394 /* Terminate process */ 1395 exit(res); 1396 } 1397 1398 void 1399 monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor) 1400 { 1401 ssh_clear_newkeys(ssh, MODE_IN); 1402 ssh_clear_newkeys(ssh, MODE_OUT); 1403 sshbuf_free(child_state); 1404 child_state = NULL; 1405 } 1406 1407 void 1408 monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor) 1409 { 1410 struct kex *kex; 1411 int r; 1412 1413 debug3_f("packet_set_state"); 1414 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1415 fatal_fr(r, "packet_set_state"); 1416 sshbuf_free(child_state); 1417 child_state = NULL; 1418 1419 if ((kex = ssh->kex) != NULL) { 1420 /* XXX set callbacks */ 1421 #ifdef WITH_OPENSSL 1422 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server; 1423 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server; 1424 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server; 1425 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server; 1426 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server; 1427 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1428 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1429 kex->kex[KEX_ECDH_SHA2] = kex_gen_server; 1430 #endif 1431 kex->kex[KEX_C25519_SHA256] = kex_gen_server; 1432 kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server; 1433 kex->load_host_public_key=&get_hostkey_public_by_type; 1434 kex->load_host_private_key=&get_hostkey_private_by_type; 1435 kex->host_key_index=&get_hostkey_index; 1436 kex->sign = sshd_hostkey_sign; 1437 } 1438 } 1439 1440 /* This function requires careful sanity checking */ 1441 1442 void 1443 mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor) 1444 { 1445 debug3_f("Waiting for new keys"); 1446 1447 if ((child_state = sshbuf_new()) == NULL) 1448 fatal_f("sshbuf_new failed"); 1449 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1450 child_state); 1451 debug3_f("GOT new keys"); 1452 } 1453 1454 1455 /* XXX */ 1456 1457 #define FD_CLOSEONEXEC(x) do { \ 1458 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1459 fatal("fcntl(%d, F_SETFD)", x); \ 1460 } while (0) 1461 1462 static void 1463 monitor_openfds(struct monitor *mon, int do_logfds) 1464 { 1465 int pair[2]; 1466 #ifdef SO_ZEROIZE 1467 int on = 1; 1468 #endif 1469 1470 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1471 fatal_f("socketpair: %s", strerror(errno)); 1472 #ifdef SO_ZEROIZE 1473 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1474 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno)); 1475 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1476 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno)); 1477 #endif 1478 FD_CLOSEONEXEC(pair[0]); 1479 FD_CLOSEONEXEC(pair[1]); 1480 mon->m_recvfd = pair[0]; 1481 mon->m_sendfd = pair[1]; 1482 1483 if (do_logfds) { 1484 if (pipe(pair) == -1) 1485 fatal_f("pipe: %s", strerror(errno)); 1486 FD_CLOSEONEXEC(pair[0]); 1487 FD_CLOSEONEXEC(pair[1]); 1488 mon->m_log_recvfd = pair[0]; 1489 mon->m_log_sendfd = pair[1]; 1490 } else 1491 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1492 } 1493 1494 #define MM_MEMSIZE 65536 1495 1496 struct monitor * 1497 monitor_init(void) 1498 { 1499 struct monitor *mon; 1500 1501 mon = xcalloc(1, sizeof(*mon)); 1502 monitor_openfds(mon, 1); 1503 1504 return mon; 1505 } 1506 1507 void 1508 monitor_reinit(struct monitor *mon) 1509 { 1510 monitor_openfds(mon, 0); 1511 } 1512 1513 #ifdef GSSAPI 1514 int 1515 mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1516 { 1517 gss_OID_desc goid; 1518 OM_uint32 major; 1519 size_t len; 1520 u_char *p; 1521 int r; 1522 1523 if (!options.gss_authentication) 1524 fatal_f("GSSAPI authentication not enabled"); 1525 1526 if ((r = sshbuf_get_string(m, &p, &len)) != 0) 1527 fatal_fr(r, "parse"); 1528 goid.elements = p; 1529 goid.length = len; 1530 1531 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1532 1533 free(goid.elements); 1534 1535 sshbuf_reset(m); 1536 if ((r = sshbuf_put_u32(m, major)) != 0) 1537 fatal_fr(r, "assemble"); 1538 1539 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1540 1541 /* Now we have a context, enable the step */ 1542 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1543 1544 return (0); 1545 } 1546 1547 int 1548 mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1549 { 1550 gss_buffer_desc in; 1551 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1552 OM_uint32 major, minor; 1553 OM_uint32 flags = 0; /* GSI needs this */ 1554 int r; 1555 1556 if (!options.gss_authentication) 1557 fatal_f("GSSAPI authentication not enabled"); 1558 1559 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0) 1560 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1561 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1562 free(in.value); 1563 1564 sshbuf_reset(m); 1565 if ((r = sshbuf_put_u32(m, major)) != 0 || 1566 (r = sshbuf_put_string(m, out.value, out.length)) != 0 || 1567 (r = sshbuf_put_u32(m, flags)) != 0) 1568 fatal_fr(r, "assemble"); 1569 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1570 1571 gss_release_buffer(&minor, &out); 1572 1573 if (major == GSS_S_COMPLETE) { 1574 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1575 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1576 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1577 } 1578 return (0); 1579 } 1580 1581 int 1582 mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m) 1583 { 1584 gss_buffer_desc gssbuf, mic; 1585 OM_uint32 ret; 1586 int r; 1587 1588 if (!options.gss_authentication) 1589 fatal_f("GSSAPI authentication not enabled"); 1590 1591 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 || 1592 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0) 1593 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1594 1595 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1596 1597 free(gssbuf.value); 1598 free(mic.value); 1599 1600 sshbuf_reset(m); 1601 if ((r = sshbuf_put_u32(m, ret)) != 0) 1602 fatal_fr(r, "assemble"); 1603 1604 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1605 1606 if (!GSS_ERROR(ret)) 1607 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1608 1609 return (0); 1610 } 1611 1612 int 1613 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m) 1614 { 1615 int r, authenticated; 1616 const char *displayname; 1617 1618 if (!options.gss_authentication) 1619 fatal_f("GSSAPI authentication not enabled"); 1620 1621 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1622 1623 sshbuf_reset(m); 1624 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 1625 fatal_fr(r, "assemble"); 1626 1627 debug3_f("sending result %d", authenticated); 1628 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1629 1630 auth_method = "gssapi-with-mic"; 1631 1632 if ((displayname = ssh_gssapi_displayname()) != NULL) 1633 auth2_record_info(authctxt, "%s", displayname); 1634 1635 /* Monitor loop will terminate if authenticated */ 1636 return (authenticated); 1637 } 1638 #endif /* GSSAPI */ 1639 1640