1 /* $OpenBSD: monitor.c,v 1.161 2016/07/22 03:39:13 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 51 #include "atomicio.h" 52 #include "xmalloc.h" 53 #include "ssh.h" 54 #include "key.h" 55 #include "buffer.h" 56 #include "hostfile.h" 57 #include "auth.h" 58 #include "cipher.h" 59 #include "kex.h" 60 #include "dh.h" 61 #include <zlib.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 #include "monitor_mm.h" 74 #ifdef GSSAPI 75 #include "ssh-gss.h" 76 #endif 77 #include "monitor_wrap.h" 78 #include "monitor_fdpass.h" 79 #include "compat.h" 80 #include "ssh2.h" 81 #include "authfd.h" 82 #include "match.h" 83 #include "ssherr.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 Buffer auth_debug; 94 extern int auth_debug_init; 95 extern Buffer loginmsg; 96 97 /* State exported from the child */ 98 static struct sshbuf *child_state; 99 100 /* Functions on the monitor that answer unprivileged requests */ 101 102 int mm_answer_moduli(int, Buffer *); 103 int mm_answer_sign(int, Buffer *); 104 int mm_answer_pwnamallow(int, Buffer *); 105 int mm_answer_auth2_read_banner(int, Buffer *); 106 int mm_answer_authserv(int, Buffer *); 107 int mm_answer_authpassword(int, Buffer *); 108 int mm_answer_bsdauthquery(int, Buffer *); 109 int mm_answer_bsdauthrespond(int, Buffer *); 110 int mm_answer_skeyquery(int, Buffer *); 111 int mm_answer_skeyrespond(int, Buffer *); 112 int mm_answer_keyallowed(int, Buffer *); 113 int mm_answer_keyverify(int, Buffer *); 114 int mm_answer_pty(int, Buffer *); 115 int mm_answer_pty_cleanup(int, Buffer *); 116 int mm_answer_term(int, Buffer *); 117 int mm_answer_rsa_keyallowed(int, Buffer *); 118 int mm_answer_rsa_challenge(int, Buffer *); 119 int mm_answer_rsa_response(int, Buffer *); 120 int mm_answer_sesskey(int, Buffer *); 121 int mm_answer_sessid(int, Buffer *); 122 123 #ifdef GSSAPI 124 int mm_answer_gss_setup_ctx(int, Buffer *); 125 int mm_answer_gss_accept_ctx(int, Buffer *); 126 int mm_answer_gss_userok(int, Buffer *); 127 int mm_answer_gss_checkmic(int, Buffer *); 128 #endif 129 130 static int monitor_read_log(struct monitor *); 131 132 static Authctxt *authctxt; 133 134 #ifdef WITH_SSH1 135 static BIGNUM *ssh1_challenge = NULL; /* used for ssh1 rsa auth */ 136 #endif 137 138 /* local state for key verify */ 139 static u_char *key_blob = NULL; 140 static u_int key_bloblen = 0; 141 static int key_blobtype = MM_NOKEY; 142 static char *hostbased_cuser = NULL; 143 static char *hostbased_chost = NULL; 144 static char *auth_method = "unknown"; 145 static char *auth_submethod = NULL; 146 static u_int session_id2_len = 0; 147 static u_char *session_id2 = NULL; 148 static pid_t monitor_child_pid; 149 150 struct mon_table { 151 enum monitor_reqtype type; 152 int flags; 153 int (*f)(int, Buffer *); 154 }; 155 156 #define MON_ISAUTH 0x0004 /* Required for Authentication */ 157 #define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 158 #define MON_ONCE 0x0010 /* Disable after calling */ 159 #define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 160 161 #define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 162 163 #define MON_PERMIT 0x1000 /* Request is permitted */ 164 165 struct mon_table mon_dispatch_proto20[] = { 166 #ifdef WITH_OPENSSL 167 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 168 #endif 169 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 170 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 171 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 172 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 173 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 174 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 175 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 176 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 177 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 178 #ifdef GSSAPI 179 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 180 {MONITOR_REQ_GSSSTEP, MON_ISAUTH, mm_answer_gss_accept_ctx}, 181 {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok}, 182 {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, mm_answer_gss_checkmic}, 183 #endif 184 {0, 0, NULL} 185 }; 186 187 struct mon_table mon_dispatch_postauth20[] = { 188 #ifdef WITH_OPENSSL 189 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 190 #endif 191 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 192 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 193 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 194 {MONITOR_REQ_TERM, 0, mm_answer_term}, 195 {0, 0, NULL} 196 }; 197 198 struct mon_table mon_dispatch_proto15[] = { 199 #ifdef WITH_SSH1 200 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 201 {MONITOR_REQ_SESSKEY, MON_ONCE, mm_answer_sesskey}, 202 {MONITOR_REQ_SESSID, MON_ONCE, mm_answer_sessid}, 203 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 204 {MONITOR_REQ_RSAKEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_rsa_keyallowed}, 205 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_keyallowed}, 206 {MONITOR_REQ_RSACHALLENGE, MON_ONCE, mm_answer_rsa_challenge}, 207 {MONITOR_REQ_RSARESPONSE, MON_ONCE|MON_AUTHDECIDE, mm_answer_rsa_response}, 208 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 209 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 210 #endif 211 {0, 0, NULL} 212 }; 213 214 struct mon_table mon_dispatch_postauth15[] = { 215 #ifdef WITH_SSH1 216 {MONITOR_REQ_PTY, MON_ONCE, mm_answer_pty}, 217 {MONITOR_REQ_PTYCLEANUP, MON_ONCE, mm_answer_pty_cleanup}, 218 {MONITOR_REQ_TERM, 0, mm_answer_term}, 219 #endif 220 {0, 0, NULL} 221 }; 222 223 struct mon_table *mon_dispatch; 224 225 /* Specifies if a certain message is allowed at the moment */ 226 227 static void 228 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 229 { 230 while (ent->f != NULL) { 231 if (ent->type == type) { 232 ent->flags &= ~MON_PERMIT; 233 ent->flags |= permit ? MON_PERMIT : 0; 234 return; 235 } 236 ent++; 237 } 238 } 239 240 static void 241 monitor_permit_authentications(int permit) 242 { 243 struct mon_table *ent = mon_dispatch; 244 245 while (ent->f != NULL) { 246 if (ent->flags & MON_AUTH) { 247 ent->flags &= ~MON_PERMIT; 248 ent->flags |= permit ? MON_PERMIT : 0; 249 } 250 ent++; 251 } 252 } 253 254 void 255 monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor) 256 { 257 struct mon_table *ent; 258 int authenticated = 0, partial = 0; 259 260 debug3("preauth child monitor started"); 261 262 close(pmonitor->m_recvfd); 263 close(pmonitor->m_log_sendfd); 264 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 265 266 authctxt = _authctxt; 267 memset(authctxt, 0, sizeof(*authctxt)); 268 269 if (compat20) { 270 mon_dispatch = mon_dispatch_proto20; 271 272 /* Permit requests for moduli and signatures */ 273 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 274 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 275 } else { 276 mon_dispatch = mon_dispatch_proto15; 277 278 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1); 279 } 280 281 /* The first few requests do not require asynchronous access */ 282 while (!authenticated) { 283 partial = 0; 284 auth_method = "unknown"; 285 auth_submethod = NULL; 286 authenticated = (monitor_read(pmonitor, mon_dispatch, &ent) == 1); 287 288 /* Special handling for multiple required authentications */ 289 if (options.num_auth_methods != 0) { 290 if (!compat20) 291 fatal("AuthenticationMethods is not supported" 292 "with SSH protocol 1"); 293 if (authenticated && 294 !auth2_update_methods_lists(authctxt, 295 auth_method, auth_submethod)) { 296 debug3("%s: method %s: partial", __func__, 297 auth_method); 298 authenticated = 0; 299 partial = 1; 300 } 301 } 302 303 if (authenticated) { 304 if (!(ent->flags & MON_AUTHDECIDE)) 305 fatal("%s: unexpected authentication from %d", 306 __func__, ent->type); 307 if (authctxt->pw->pw_uid == 0 && 308 !auth_root_allowed(auth_method)) 309 authenticated = 0; 310 } 311 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 312 auth_log(authctxt, authenticated, partial, 313 auth_method, auth_submethod); 314 if (!partial && !authenticated) 315 authctxt->failures++; 316 } 317 } 318 319 if (!authctxt->valid) 320 fatal("%s: authenticated invalid user", __func__); 321 if (strcmp(auth_method, "unknown") == 0) 322 fatal("%s: authentication method name unknown", __func__); 323 324 debug("%s: %s has been authenticated by privileged process", 325 __func__, authctxt->user); 326 327 mm_get_keystate(pmonitor); 328 329 /* Drain any buffered messages from the child */ 330 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 331 ; 332 333 close(pmonitor->m_sendfd); 334 close(pmonitor->m_log_recvfd); 335 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 336 } 337 338 static void 339 monitor_set_child_handler(pid_t pid) 340 { 341 monitor_child_pid = pid; 342 } 343 344 static void 345 monitor_child_handler(int sig) 346 { 347 kill(monitor_child_pid, sig); 348 } 349 350 void 351 monitor_child_postauth(struct monitor *pmonitor) 352 { 353 close(pmonitor->m_recvfd); 354 pmonitor->m_recvfd = -1; 355 356 monitor_set_child_handler(pmonitor->m_pid); 357 signal(SIGHUP, &monitor_child_handler); 358 signal(SIGTERM, &monitor_child_handler); 359 signal(SIGINT, &monitor_child_handler); 360 361 if (compat20) { 362 mon_dispatch = mon_dispatch_postauth20; 363 364 /* Permit requests for moduli and signatures */ 365 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 366 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 367 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 368 } else { 369 mon_dispatch = mon_dispatch_postauth15; 370 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 371 } 372 if (!no_pty_flag) { 373 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 374 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 375 } 376 377 for (;;) 378 monitor_read(pmonitor, mon_dispatch, NULL); 379 } 380 381 void 382 monitor_sync(struct monitor *pmonitor) 383 { 384 if (options.compression) { 385 /* The member allocation is not visible, so sync it */ 386 mm_share_sync(&pmonitor->m_zlib, &pmonitor->m_zback); 387 } 388 } 389 390 /* Allocation functions for zlib */ 391 static void * 392 mm_zalloc(struct mm_master *mm, u_int ncount, u_int size) 393 { 394 if (size == 0 || ncount == 0 || ncount > SIZE_MAX / size) 395 fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size); 396 397 return mm_malloc(mm, size * ncount); 398 } 399 400 static void 401 mm_zfree(struct mm_master *mm, void *address) 402 { 403 mm_free(mm, address); 404 } 405 406 static int 407 monitor_read_log(struct monitor *pmonitor) 408 { 409 Buffer logmsg; 410 u_int len, level; 411 char *msg; 412 413 buffer_init(&logmsg); 414 415 /* Read length */ 416 buffer_append_space(&logmsg, 4); 417 if (atomicio(read, pmonitor->m_log_recvfd, 418 buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) { 419 if (errno == EPIPE) { 420 buffer_free(&logmsg); 421 debug("%s: child log fd closed", __func__); 422 close(pmonitor->m_log_recvfd); 423 pmonitor->m_log_recvfd = -1; 424 return -1; 425 } 426 fatal("%s: log fd read: %s", __func__, strerror(errno)); 427 } 428 len = buffer_get_int(&logmsg); 429 if (len <= 4 || len > 8192) 430 fatal("%s: invalid log message length %u", __func__, len); 431 432 /* Read severity, message */ 433 buffer_clear(&logmsg); 434 buffer_append_space(&logmsg, len); 435 if (atomicio(read, pmonitor->m_log_recvfd, 436 buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) 437 fatal("%s: log fd read: %s", __func__, strerror(errno)); 438 439 /* Log it */ 440 level = buffer_get_int(&logmsg); 441 msg = buffer_get_string(&logmsg, NULL); 442 if (log_level_name(level) == NULL) 443 fatal("%s: invalid log level %u (corrupted message?)", 444 __func__, level); 445 do_log2(level, "%s [preauth]", msg); 446 447 buffer_free(&logmsg); 448 free(msg); 449 450 return 0; 451 } 452 453 int 454 monitor_read(struct monitor *pmonitor, struct mon_table *ent, 455 struct mon_table **pent) 456 { 457 Buffer m; 458 int ret; 459 u_char type; 460 struct pollfd pfd[2]; 461 462 for (;;) { 463 memset(&pfd, 0, sizeof(pfd)); 464 pfd[0].fd = pmonitor->m_sendfd; 465 pfd[0].events = POLLIN; 466 pfd[1].fd = pmonitor->m_log_recvfd; 467 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 468 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 469 if (errno == EINTR || errno == EAGAIN) 470 continue; 471 fatal("%s: poll: %s", __func__, strerror(errno)); 472 } 473 if (pfd[1].revents) { 474 /* 475 * Drain all log messages before processing next 476 * monitor request. 477 */ 478 monitor_read_log(pmonitor); 479 continue; 480 } 481 if (pfd[0].revents) 482 break; /* Continues below */ 483 } 484 485 buffer_init(&m); 486 487 mm_request_receive(pmonitor->m_sendfd, &m); 488 type = buffer_get_char(&m); 489 490 debug3("%s: checking request %d", __func__, type); 491 492 while (ent->f != NULL) { 493 if (ent->type == type) 494 break; 495 ent++; 496 } 497 498 if (ent->f != NULL) { 499 if (!(ent->flags & MON_PERMIT)) 500 fatal("%s: unpermitted request %d", __func__, 501 type); 502 ret = (*ent->f)(pmonitor->m_sendfd, &m); 503 buffer_free(&m); 504 505 /* The child may use this request only once, disable it */ 506 if (ent->flags & MON_ONCE) { 507 debug2("%s: %d used once, disabling now", __func__, 508 type); 509 ent->flags &= ~MON_PERMIT; 510 } 511 512 if (pent != NULL) 513 *pent = ent; 514 515 return ret; 516 } 517 518 fatal("%s: unsupported request: %d", __func__, type); 519 520 /* NOTREACHED */ 521 return (-1); 522 } 523 524 /* allowed key state */ 525 static int 526 monitor_allowed_key(u_char *blob, u_int bloblen) 527 { 528 /* make sure key is allowed */ 529 if (key_blob == NULL || key_bloblen != bloblen || 530 timingsafe_bcmp(key_blob, blob, key_bloblen)) 531 return (0); 532 return (1); 533 } 534 535 static void 536 monitor_reset_key_state(void) 537 { 538 /* reset state */ 539 free(key_blob); 540 free(hostbased_cuser); 541 free(hostbased_chost); 542 key_blob = NULL; 543 key_bloblen = 0; 544 key_blobtype = MM_NOKEY; 545 hostbased_cuser = NULL; 546 hostbased_chost = NULL; 547 } 548 549 #ifdef WITH_OPENSSL 550 int 551 mm_answer_moduli(int sock, Buffer *m) 552 { 553 DH *dh; 554 int min, want, max; 555 556 min = buffer_get_int(m); 557 want = buffer_get_int(m); 558 max = buffer_get_int(m); 559 560 debug3("%s: got parameters: %d %d %d", 561 __func__, min, want, max); 562 /* We need to check here, too, in case the child got corrupted */ 563 if (max < min || want < min || max < want) 564 fatal("%s: bad parameters: %d %d %d", 565 __func__, min, want, max); 566 567 buffer_clear(m); 568 569 dh = choose_dh(min, want, max); 570 if (dh == NULL) { 571 buffer_put_char(m, 0); 572 return (0); 573 } else { 574 /* Send first bignum */ 575 buffer_put_char(m, 1); 576 buffer_put_bignum2(m, dh->p); 577 buffer_put_bignum2(m, dh->g); 578 579 DH_free(dh); 580 } 581 mm_request_send(sock, MONITOR_ANS_MODULI, m); 582 return (0); 583 } 584 #endif 585 586 int 587 mm_answer_sign(int sock, Buffer *m) 588 { 589 struct ssh *ssh = active_state; /* XXX */ 590 extern int auth_sock; /* XXX move to state struct? */ 591 struct sshkey *key; 592 struct sshbuf *sigbuf = NULL; 593 u_char *p = NULL, *signature = NULL; 594 char *alg = NULL; 595 size_t datlen, siglen, alglen; 596 int r, is_proof = 0; 597 u_int keyid; 598 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 599 600 debug3("%s", __func__); 601 602 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 603 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 604 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0) 605 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 606 if (keyid > INT_MAX) 607 fatal("%s: invalid key ID", __func__); 608 609 /* 610 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 611 * SHA384 (48 bytes) and SHA512 (64 bytes). 612 * 613 * Otherwise, verify the signature request is for a hostkey 614 * proof. 615 * 616 * XXX perform similar check for KEX signature requests too? 617 * it's not trivial, since what is signed is the hash, rather 618 * than the full kex structure... 619 */ 620 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 621 /* 622 * Construct expected hostkey proof and compare it to what 623 * the client sent us. 624 */ 625 if (session_id2_len == 0) /* hostkeys is never first */ 626 fatal("%s: bad data length: %zu", __func__, datlen); 627 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 628 fatal("%s: no hostkey for index %d", __func__, keyid); 629 if ((sigbuf = sshbuf_new()) == NULL) 630 fatal("%s: sshbuf_new", __func__); 631 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 632 (r = sshbuf_put_string(sigbuf, session_id2, 633 session_id2_len)) != 0 || 634 (r = sshkey_puts(key, sigbuf)) != 0) 635 fatal("%s: couldn't prepare private key " 636 "proof buffer: %s", __func__, ssh_err(r)); 637 if (datlen != sshbuf_len(sigbuf) || 638 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 639 fatal("%s: bad data length: %zu, hostkey proof len %zu", 640 __func__, datlen, sshbuf_len(sigbuf)); 641 sshbuf_free(sigbuf); 642 is_proof = 1; 643 } 644 645 /* save session id, it will be passed on the first call */ 646 if (session_id2_len == 0) { 647 session_id2_len = datlen; 648 session_id2 = xmalloc(session_id2_len); 649 memcpy(session_id2, p, session_id2_len); 650 } 651 652 if ((key = get_hostkey_by_index(keyid)) != NULL) { 653 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 654 datafellows)) != 0) 655 fatal("%s: sshkey_sign failed: %s", 656 __func__, ssh_err(r)); 657 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 658 auth_sock > 0) { 659 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 660 p, datlen, alg, datafellows)) != 0) { 661 fatal("%s: ssh_agent_sign failed: %s", 662 __func__, ssh_err(r)); 663 } 664 } else 665 fatal("%s: no hostkey from index %d", __func__, keyid); 666 667 debug3("%s: %s signature %p(%zu)", __func__, 668 is_proof ? "KEX" : "hostkey proof", signature, siglen); 669 670 sshbuf_reset(m); 671 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 672 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 673 674 free(alg); 675 free(p); 676 free(signature); 677 678 mm_request_send(sock, MONITOR_ANS_SIGN, m); 679 680 /* Turn on permissions for getpwnam */ 681 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 682 683 return (0); 684 } 685 686 /* Retrieves the password entry and also checks if the user is permitted */ 687 688 int 689 mm_answer_pwnamallow(int sock, Buffer *m) 690 { 691 char *username; 692 struct passwd *pwent; 693 int allowed = 0; 694 u_int i; 695 696 debug3("%s", __func__); 697 698 if (authctxt->attempt++ != 0) 699 fatal("%s: multiple attempts for getpwnam", __func__); 700 701 username = buffer_get_string(m, NULL); 702 703 pwent = getpwnamallow(username); 704 705 authctxt->user = xstrdup(username); 706 setproctitle("%s [priv]", pwent ? username : "unknown"); 707 free(username); 708 709 buffer_clear(m); 710 711 if (pwent == NULL) { 712 buffer_put_char(m, 0); 713 authctxt->pw = fakepw(); 714 goto out; 715 } 716 717 allowed = 1; 718 authctxt->pw = pwent; 719 authctxt->valid = 1; 720 721 buffer_put_char(m, 1); 722 buffer_put_string(m, pwent, sizeof(struct passwd)); 723 buffer_put_cstring(m, pwent->pw_name); 724 buffer_put_cstring(m, "*"); 725 buffer_put_cstring(m, pwent->pw_gecos); 726 buffer_put_cstring(m, pwent->pw_class); 727 buffer_put_cstring(m, pwent->pw_dir); 728 buffer_put_cstring(m, pwent->pw_shell); 729 730 out: 731 buffer_put_string(m, &options, sizeof(options)); 732 733 #define M_CP_STROPT(x) do { \ 734 if (options.x != NULL) \ 735 buffer_put_cstring(m, options.x); \ 736 } while (0) 737 #define M_CP_STRARRAYOPT(x, nx) do { \ 738 for (i = 0; i < options.nx; i++) \ 739 buffer_put_cstring(m, options.x[i]); \ 740 } while (0) 741 /* See comment in servconf.h */ 742 COPY_MATCH_STRING_OPTS(); 743 #undef M_CP_STROPT 744 #undef M_CP_STRARRAYOPT 745 746 /* Create valid auth method lists */ 747 if (compat20 && auth2_setup_methods_lists(authctxt) != 0) { 748 /* 749 * The monitor will continue long enough to let the child 750 * run to it's packet_disconnect(), but it must not allow any 751 * authentication to succeed. 752 */ 753 debug("%s: no valid authentication method lists", __func__); 754 } 755 756 debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed); 757 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 758 759 /* For SSHv1 allow authentication now */ 760 if (!compat20) 761 monitor_permit_authentications(1); 762 else { 763 /* Allow service/style information on the auth context */ 764 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 765 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 766 } 767 768 return (0); 769 } 770 771 int mm_answer_auth2_read_banner(int sock, Buffer *m) 772 { 773 char *banner; 774 775 buffer_clear(m); 776 banner = auth2_read_banner(); 777 buffer_put_cstring(m, banner != NULL ? banner : ""); 778 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 779 free(banner); 780 781 return (0); 782 } 783 784 int 785 mm_answer_authserv(int sock, Buffer *m) 786 { 787 monitor_permit_authentications(1); 788 789 authctxt->service = buffer_get_string(m, NULL); 790 authctxt->style = buffer_get_string(m, NULL); 791 debug3("%s: service=%s, style=%s", 792 __func__, authctxt->service, authctxt->style); 793 794 if (strlen(authctxt->style) == 0) { 795 free(authctxt->style); 796 authctxt->style = NULL; 797 } 798 799 return (0); 800 } 801 802 int 803 mm_answer_authpassword(int sock, Buffer *m) 804 { 805 static int call_count; 806 char *passwd; 807 int authenticated; 808 u_int plen; 809 810 passwd = buffer_get_string(m, &plen); 811 /* Only authenticate if the context is valid */ 812 authenticated = options.password_authentication && 813 auth_password(authctxt, passwd); 814 explicit_bzero(passwd, strlen(passwd)); 815 free(passwd); 816 817 buffer_clear(m); 818 buffer_put_int(m, authenticated); 819 820 debug3("%s: sending result %d", __func__, authenticated); 821 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 822 823 call_count++; 824 if (plen == 0 && call_count == 1) 825 auth_method = "none"; 826 else 827 auth_method = "password"; 828 829 /* Causes monitor loop to terminate if authenticated */ 830 return (authenticated); 831 } 832 833 int 834 mm_answer_bsdauthquery(int sock, Buffer *m) 835 { 836 char *name, *infotxt; 837 u_int numprompts; 838 u_int *echo_on; 839 char **prompts; 840 u_int success; 841 842 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 843 &prompts, &echo_on) < 0 ? 0 : 1; 844 845 buffer_clear(m); 846 buffer_put_int(m, success); 847 if (success) 848 buffer_put_cstring(m, prompts[0]); 849 850 debug3("%s: sending challenge success: %u", __func__, success); 851 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 852 853 if (success) { 854 free(name); 855 free(infotxt); 856 free(prompts); 857 free(echo_on); 858 } 859 860 return (0); 861 } 862 863 int 864 mm_answer_bsdauthrespond(int sock, Buffer *m) 865 { 866 char *response; 867 int authok; 868 869 if (authctxt->as == NULL) 870 fatal("%s: no bsd auth session", __func__); 871 872 response = buffer_get_string(m, NULL); 873 authok = options.challenge_response_authentication && 874 auth_userresponse(authctxt->as, response, 0); 875 authctxt->as = NULL; 876 debug3("%s: <%s> = <%d>", __func__, response, authok); 877 free(response); 878 879 buffer_clear(m); 880 buffer_put_int(m, authok); 881 882 debug3("%s: sending authenticated: %d", __func__, authok); 883 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 884 885 if (compat20) { 886 auth_method = "keyboard-interactive"; 887 auth_submethod = "bsdauth"; 888 } else 889 auth_method = "bsdauth"; 890 891 return (authok != 0); 892 } 893 894 int 895 mm_answer_keyallowed(int sock, Buffer *m) 896 { 897 Key *key; 898 char *cuser, *chost; 899 u_char *blob; 900 u_int bloblen, pubkey_auth_attempt; 901 enum mm_keytype type = 0; 902 int allowed = 0; 903 904 debug3("%s entering", __func__); 905 906 type = buffer_get_int(m); 907 cuser = buffer_get_string(m, NULL); 908 chost = buffer_get_string(m, NULL); 909 blob = buffer_get_string(m, &bloblen); 910 pubkey_auth_attempt = buffer_get_int(m); 911 912 key = key_from_blob(blob, bloblen); 913 914 if ((compat20 && type == MM_RSAHOSTKEY) || 915 (!compat20 && type != MM_RSAHOSTKEY)) 916 fatal("%s: key type and protocol mismatch", __func__); 917 918 debug3("%s: key_from_blob: %p", __func__, key); 919 920 if (key != NULL && authctxt->valid) { 921 /* These should not make it past the privsep child */ 922 if (key_type_plain(key->type) == KEY_RSA && 923 (datafellows & SSH_BUG_RSASIGMD5) != 0) 924 fatal("%s: passed a SSH_BUG_RSASIGMD5 key", __func__); 925 926 switch (type) { 927 case MM_USERKEY: 928 allowed = options.pubkey_authentication && 929 !auth2_userkey_already_used(authctxt, key) && 930 match_pattern_list(sshkey_ssh_name(key), 931 options.pubkey_key_types, 0) == 1 && 932 user_key_allowed(authctxt->pw, key, 933 pubkey_auth_attempt); 934 pubkey_auth_info(authctxt, key, NULL); 935 auth_method = "publickey"; 936 if (options.pubkey_authentication && 937 (!pubkey_auth_attempt || allowed != 1)) 938 auth_clear_options(); 939 break; 940 case MM_HOSTKEY: 941 allowed = options.hostbased_authentication && 942 match_pattern_list(sshkey_ssh_name(key), 943 options.hostbased_key_types, 0) == 1 && 944 hostbased_key_allowed(authctxt->pw, 945 cuser, chost, key); 946 pubkey_auth_info(authctxt, key, 947 "client user \"%.100s\", client host \"%.100s\"", 948 cuser, chost); 949 auth_method = "hostbased"; 950 break; 951 #ifdef WITH_SSH1 952 case MM_RSAHOSTKEY: 953 key->type = KEY_RSA1; /* XXX */ 954 allowed = options.rhosts_rsa_authentication && 955 auth_rhosts_rsa_key_allowed(authctxt->pw, 956 cuser, chost, key); 957 if (options.rhosts_rsa_authentication && allowed != 1) 958 auth_clear_options(); 959 auth_method = "rsa"; 960 break; 961 #endif 962 default: 963 fatal("%s: unknown key type %d", __func__, type); 964 break; 965 } 966 } 967 968 debug3("%s: key %p is %s", 969 __func__, key, allowed ? "allowed" : "not allowed"); 970 971 if (key != NULL) 972 key_free(key); 973 974 /* clear temporarily storage (used by verify) */ 975 monitor_reset_key_state(); 976 977 if (allowed) { 978 /* Save temporarily for comparison in verify */ 979 key_blob = blob; 980 key_bloblen = bloblen; 981 key_blobtype = type; 982 hostbased_cuser = cuser; 983 hostbased_chost = chost; 984 } else { 985 /* Log failed attempt */ 986 auth_log(authctxt, 0, 0, auth_method, NULL); 987 free(blob); 988 free(cuser); 989 free(chost); 990 } 991 992 buffer_clear(m); 993 buffer_put_int(m, allowed); 994 buffer_put_int(m, forced_command != NULL); 995 996 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 997 998 if (type == MM_RSAHOSTKEY) 999 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed); 1000 1001 return (0); 1002 } 1003 1004 static int 1005 monitor_valid_userblob(u_char *data, u_int datalen) 1006 { 1007 Buffer b; 1008 u_char *p; 1009 char *userstyle, *cp; 1010 u_int len; 1011 int fail = 0; 1012 1013 buffer_init(&b); 1014 buffer_append(&b, data, datalen); 1015 1016 if (datafellows & SSH_OLD_SESSIONID) { 1017 p = buffer_ptr(&b); 1018 len = buffer_len(&b); 1019 if ((session_id2 == NULL) || 1020 (len < session_id2_len) || 1021 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1022 fail++; 1023 buffer_consume(&b, session_id2_len); 1024 } else { 1025 p = buffer_get_string(&b, &len); 1026 if ((session_id2 == NULL) || 1027 (len != session_id2_len) || 1028 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1029 fail++; 1030 free(p); 1031 } 1032 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 1033 fail++; 1034 cp = buffer_get_cstring(&b, NULL); 1035 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1036 authctxt->style ? ":" : "", 1037 authctxt->style ? authctxt->style : ""); 1038 if (strcmp(userstyle, cp) != 0) { 1039 logit("wrong user name passed to monitor: " 1040 "expected %s != %.100s", userstyle, cp); 1041 fail++; 1042 } 1043 free(userstyle); 1044 free(cp); 1045 buffer_skip_string(&b); 1046 if (datafellows & SSH_BUG_PKAUTH) { 1047 if (!buffer_get_char(&b)) 1048 fail++; 1049 } else { 1050 cp = buffer_get_cstring(&b, NULL); 1051 if (strcmp("publickey", cp) != 0) 1052 fail++; 1053 free(cp); 1054 if (!buffer_get_char(&b)) 1055 fail++; 1056 buffer_skip_string(&b); 1057 } 1058 buffer_skip_string(&b); 1059 if (buffer_len(&b) != 0) 1060 fail++; 1061 buffer_free(&b); 1062 return (fail == 0); 1063 } 1064 1065 static int 1066 monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser, 1067 char *chost) 1068 { 1069 Buffer b; 1070 char *p, *userstyle; 1071 u_int len; 1072 int fail = 0; 1073 1074 buffer_init(&b); 1075 buffer_append(&b, data, datalen); 1076 1077 p = buffer_get_string(&b, &len); 1078 if ((session_id2 == NULL) || 1079 (len != session_id2_len) || 1080 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1081 fail++; 1082 free(p); 1083 1084 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 1085 fail++; 1086 p = buffer_get_cstring(&b, NULL); 1087 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1088 authctxt->style ? ":" : "", 1089 authctxt->style ? authctxt->style : ""); 1090 if (strcmp(userstyle, p) != 0) { 1091 logit("wrong user name passed to monitor: expected %s != %.100s", 1092 userstyle, p); 1093 fail++; 1094 } 1095 free(userstyle); 1096 free(p); 1097 buffer_skip_string(&b); /* service */ 1098 p = buffer_get_cstring(&b, NULL); 1099 if (strcmp(p, "hostbased") != 0) 1100 fail++; 1101 free(p); 1102 buffer_skip_string(&b); /* pkalg */ 1103 buffer_skip_string(&b); /* pkblob */ 1104 1105 /* verify client host, strip trailing dot if necessary */ 1106 p = buffer_get_string(&b, NULL); 1107 if (((len = strlen(p)) > 0) && p[len - 1] == '.') 1108 p[len - 1] = '\0'; 1109 if (strcmp(p, chost) != 0) 1110 fail++; 1111 free(p); 1112 1113 /* verify client user */ 1114 p = buffer_get_string(&b, NULL); 1115 if (strcmp(p, cuser) != 0) 1116 fail++; 1117 free(p); 1118 1119 if (buffer_len(&b) != 0) 1120 fail++; 1121 buffer_free(&b); 1122 return (fail == 0); 1123 } 1124 1125 int 1126 mm_answer_keyverify(int sock, Buffer *m) 1127 { 1128 Key *key; 1129 u_char *signature, *data, *blob; 1130 u_int signaturelen, datalen, bloblen; 1131 int verified = 0; 1132 int valid_data = 0; 1133 1134 blob = buffer_get_string(m, &bloblen); 1135 signature = buffer_get_string(m, &signaturelen); 1136 data = buffer_get_string(m, &datalen); 1137 1138 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1139 !monitor_allowed_key(blob, bloblen)) 1140 fatal("%s: bad key, not previously allowed", __func__); 1141 1142 key = key_from_blob(blob, bloblen); 1143 if (key == NULL) 1144 fatal("%s: bad public key blob", __func__); 1145 1146 switch (key_blobtype) { 1147 case MM_USERKEY: 1148 valid_data = monitor_valid_userblob(data, datalen); 1149 break; 1150 case MM_HOSTKEY: 1151 valid_data = monitor_valid_hostbasedblob(data, datalen, 1152 hostbased_cuser, hostbased_chost); 1153 break; 1154 default: 1155 valid_data = 0; 1156 break; 1157 } 1158 if (!valid_data) 1159 fatal("%s: bad signature data blob", __func__); 1160 1161 verified = key_verify(key, signature, signaturelen, data, datalen); 1162 debug3("%s: key %p signature %s", 1163 __func__, key, (verified == 1) ? "verified" : "unverified"); 1164 1165 /* If auth was successful then record key to ensure it isn't reused */ 1166 if (verified == 1 && key_blobtype == MM_USERKEY) 1167 auth2_record_userkey(authctxt, key); 1168 else 1169 key_free(key); 1170 1171 free(blob); 1172 free(signature); 1173 free(data); 1174 1175 auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased"; 1176 1177 monitor_reset_key_state(); 1178 1179 buffer_clear(m); 1180 buffer_put_int(m, verified); 1181 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1182 1183 return (verified == 1); 1184 } 1185 1186 static void 1187 mm_record_login(Session *s, struct passwd *pw) 1188 { 1189 struct ssh *ssh = active_state; /* XXX */ 1190 socklen_t fromlen; 1191 struct sockaddr_storage from; 1192 1193 if (options.use_login) 1194 return; 1195 1196 /* 1197 * Get IP address of client. If the connection is not a socket, let 1198 * the address be 0.0.0.0. 1199 */ 1200 memset(&from, 0, sizeof(from)); 1201 fromlen = sizeof(from); 1202 if (packet_connection_is_on_socket()) { 1203 if (getpeername(packet_get_connection_in(), 1204 (struct sockaddr *)&from, &fromlen) < 0) { 1205 debug("getpeername: %.100s", strerror(errno)); 1206 cleanup_exit(255); 1207 } 1208 } 1209 /* Record that there was a login on that tty from the remote host. */ 1210 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1211 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1212 (struct sockaddr *)&from, fromlen); 1213 } 1214 1215 static void 1216 mm_session_close(Session *s) 1217 { 1218 debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid); 1219 if (s->ttyfd != -1) { 1220 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd); 1221 session_pty_cleanup2(s); 1222 } 1223 session_unused(s->self); 1224 } 1225 1226 int 1227 mm_answer_pty(int sock, Buffer *m) 1228 { 1229 extern struct monitor *pmonitor; 1230 Session *s; 1231 int res, fd0; 1232 1233 debug3("%s entering", __func__); 1234 1235 buffer_clear(m); 1236 s = session_new(); 1237 if (s == NULL) 1238 goto error; 1239 s->authctxt = authctxt; 1240 s->pw = authctxt->pw; 1241 s->pid = pmonitor->m_pid; 1242 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1243 if (res == 0) 1244 goto error; 1245 pty_setowner(authctxt->pw, s->tty); 1246 1247 buffer_put_int(m, 1); 1248 buffer_put_cstring(m, s->tty); 1249 1250 /* We need to trick ttyslot */ 1251 if (dup2(s->ttyfd, 0) == -1) 1252 fatal("%s: dup2", __func__); 1253 1254 mm_record_login(s, authctxt->pw); 1255 1256 /* Now we can close the file descriptor again */ 1257 close(0); 1258 1259 /* send messages generated by record_login */ 1260 buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg)); 1261 buffer_clear(&loginmsg); 1262 1263 mm_request_send(sock, MONITOR_ANS_PTY, m); 1264 1265 if (mm_send_fd(sock, s->ptyfd) == -1 || 1266 mm_send_fd(sock, s->ttyfd) == -1) 1267 fatal("%s: send fds failed", __func__); 1268 1269 /* make sure nothing uses fd 0 */ 1270 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0) 1271 fatal("%s: open(/dev/null): %s", __func__, strerror(errno)); 1272 if (fd0 != 0) 1273 error("%s: fd0 %d != 0", __func__, fd0); 1274 1275 /* slave is not needed */ 1276 close(s->ttyfd); 1277 s->ttyfd = s->ptyfd; 1278 /* no need to dup() because nobody closes ptyfd */ 1279 s->ptymaster = s->ptyfd; 1280 1281 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd); 1282 1283 return (0); 1284 1285 error: 1286 if (s != NULL) 1287 mm_session_close(s); 1288 buffer_put_int(m, 0); 1289 mm_request_send(sock, MONITOR_ANS_PTY, m); 1290 return (0); 1291 } 1292 1293 int 1294 mm_answer_pty_cleanup(int sock, Buffer *m) 1295 { 1296 Session *s; 1297 char *tty; 1298 1299 debug3("%s entering", __func__); 1300 1301 tty = buffer_get_string(m, NULL); 1302 if ((s = session_by_tty(tty)) != NULL) 1303 mm_session_close(s); 1304 buffer_clear(m); 1305 free(tty); 1306 return (0); 1307 } 1308 1309 #ifdef WITH_SSH1 1310 int 1311 mm_answer_sesskey(int sock, Buffer *m) 1312 { 1313 BIGNUM *p; 1314 int rsafail; 1315 1316 /* Turn off permissions */ 1317 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 0); 1318 1319 if ((p = BN_new()) == NULL) 1320 fatal("%s: BN_new", __func__); 1321 1322 buffer_get_bignum2(m, p); 1323 1324 rsafail = ssh1_session_key(p); 1325 1326 buffer_clear(m); 1327 buffer_put_int(m, rsafail); 1328 buffer_put_bignum2(m, p); 1329 1330 BN_clear_free(p); 1331 1332 mm_request_send(sock, MONITOR_ANS_SESSKEY, m); 1333 1334 /* Turn on permissions for sessid passing */ 1335 monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1); 1336 1337 return (0); 1338 } 1339 1340 int 1341 mm_answer_sessid(int sock, Buffer *m) 1342 { 1343 int i; 1344 1345 debug3("%s entering", __func__); 1346 1347 if (buffer_len(m) != 16) 1348 fatal("%s: bad ssh1 session id", __func__); 1349 for (i = 0; i < 16; i++) 1350 session_id[i] = buffer_get_char(m); 1351 1352 /* Turn on permissions for getpwnam */ 1353 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 1354 1355 return (0); 1356 } 1357 1358 int 1359 mm_answer_rsa_keyallowed(int sock, Buffer *m) 1360 { 1361 BIGNUM *client_n; 1362 Key *key = NULL; 1363 u_char *blob = NULL; 1364 u_int blen = 0; 1365 int allowed = 0; 1366 1367 debug3("%s entering", __func__); 1368 1369 auth_method = "rsa"; 1370 if (options.rsa_authentication && authctxt->valid) { 1371 if ((client_n = BN_new()) == NULL) 1372 fatal("%s: BN_new", __func__); 1373 buffer_get_bignum2(m, client_n); 1374 allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key); 1375 BN_clear_free(client_n); 1376 } 1377 buffer_clear(m); 1378 buffer_put_int(m, allowed); 1379 buffer_put_int(m, forced_command != NULL); 1380 1381 /* clear temporarily storage (used by generate challenge) */ 1382 monitor_reset_key_state(); 1383 1384 if (allowed && key != NULL) { 1385 key->type = KEY_RSA; /* cheat for key_to_blob */ 1386 if (key_to_blob(key, &blob, &blen) == 0) 1387 fatal("%s: key_to_blob failed", __func__); 1388 buffer_put_string(m, blob, blen); 1389 1390 /* Save temporarily for comparison in verify */ 1391 key_blob = blob; 1392 key_bloblen = blen; 1393 key_blobtype = MM_RSAUSERKEY; 1394 } 1395 if (key != NULL) 1396 key_free(key); 1397 1398 mm_request_send(sock, MONITOR_ANS_RSAKEYALLOWED, m); 1399 1400 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed); 1401 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0); 1402 return (0); 1403 } 1404 1405 int 1406 mm_answer_rsa_challenge(int sock, Buffer *m) 1407 { 1408 Key *key = NULL; 1409 u_char *blob; 1410 u_int blen; 1411 1412 debug3("%s entering", __func__); 1413 1414 if (!authctxt->valid) 1415 fatal("%s: authctxt not valid", __func__); 1416 blob = buffer_get_string(m, &blen); 1417 if (!monitor_allowed_key(blob, blen)) 1418 fatal("%s: bad key, not previously allowed", __func__); 1419 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) 1420 fatal("%s: key type mismatch", __func__); 1421 if ((key = key_from_blob(blob, blen)) == NULL) 1422 fatal("%s: received bad key", __func__); 1423 if (key->type != KEY_RSA) 1424 fatal("%s: received bad key type %d", __func__, key->type); 1425 key->type = KEY_RSA1; 1426 if (ssh1_challenge) 1427 BN_clear_free(ssh1_challenge); 1428 ssh1_challenge = auth_rsa_generate_challenge(key); 1429 1430 buffer_clear(m); 1431 buffer_put_bignum2(m, ssh1_challenge); 1432 1433 debug3("%s sending reply", __func__); 1434 mm_request_send(sock, MONITOR_ANS_RSACHALLENGE, m); 1435 1436 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1); 1437 1438 free(blob); 1439 key_free(key); 1440 return (0); 1441 } 1442 1443 int 1444 mm_answer_rsa_response(int sock, Buffer *m) 1445 { 1446 Key *key = NULL; 1447 u_char *blob, *response; 1448 u_int blen, len; 1449 int success; 1450 1451 debug3("%s entering", __func__); 1452 1453 if (!authctxt->valid) 1454 fatal("%s: authctxt not valid", __func__); 1455 if (ssh1_challenge == NULL) 1456 fatal("%s: no ssh1_challenge", __func__); 1457 1458 blob = buffer_get_string(m, &blen); 1459 if (!monitor_allowed_key(blob, blen)) 1460 fatal("%s: bad key, not previously allowed", __func__); 1461 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) 1462 fatal("%s: key type mismatch: %d", __func__, key_blobtype); 1463 if ((key = key_from_blob(blob, blen)) == NULL) 1464 fatal("%s: received bad key", __func__); 1465 response = buffer_get_string(m, &len); 1466 if (len != 16) 1467 fatal("%s: received bad response to challenge", __func__); 1468 success = auth_rsa_verify_response(key, ssh1_challenge, response); 1469 1470 free(blob); 1471 key_free(key); 1472 free(response); 1473 1474 auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa"; 1475 1476 /* reset state */ 1477 BN_clear_free(ssh1_challenge); 1478 ssh1_challenge = NULL; 1479 monitor_reset_key_state(); 1480 1481 buffer_clear(m); 1482 buffer_put_int(m, success); 1483 mm_request_send(sock, MONITOR_ANS_RSARESPONSE, m); 1484 1485 return (success); 1486 } 1487 #endif 1488 1489 int 1490 mm_answer_term(int sock, Buffer *req) 1491 { 1492 extern struct monitor *pmonitor; 1493 int res, status; 1494 1495 debug3("%s: tearing down sessions", __func__); 1496 1497 /* The child is terminating */ 1498 session_destroy_all(&mm_session_close); 1499 1500 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1501 if (errno != EINTR) 1502 exit(1); 1503 1504 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1505 1506 /* Terminate process */ 1507 exit(res); 1508 } 1509 1510 void 1511 monitor_apply_keystate(struct monitor *pmonitor) 1512 { 1513 struct ssh *ssh = active_state; /* XXX */ 1514 struct kex *kex; 1515 int r; 1516 1517 debug3("%s: packet_set_state", __func__); 1518 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1519 fatal("%s: packet_set_state: %s", __func__, ssh_err(r)); 1520 sshbuf_free(child_state); 1521 child_state = NULL; 1522 1523 if ((kex = ssh->kex) != NULL) { 1524 /* XXX set callbacks */ 1525 #ifdef WITH_OPENSSL 1526 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; 1527 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; 1528 kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server; 1529 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server; 1530 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server; 1531 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1532 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1533 kex->kex[KEX_ECDH_SHA2] = kexecdh_server; 1534 #endif 1535 kex->kex[KEX_C25519_SHA256] = kexc25519_server; 1536 kex->load_host_public_key=&get_hostkey_public_by_type; 1537 kex->load_host_private_key=&get_hostkey_private_by_type; 1538 kex->host_key_index=&get_hostkey_index; 1539 kex->sign = sshd_hostkey_sign; 1540 } 1541 1542 /* Update with new address */ 1543 if (options.compression) { 1544 ssh_packet_set_compress_hooks(ssh, pmonitor->m_zlib, 1545 (ssh_packet_comp_alloc_func *)mm_zalloc, 1546 (ssh_packet_comp_free_func *)mm_zfree); 1547 } 1548 } 1549 1550 /* This function requries careful sanity checking */ 1551 1552 void 1553 mm_get_keystate(struct monitor *pmonitor) 1554 { 1555 debug3("%s: Waiting for new keys", __func__); 1556 1557 if ((child_state = sshbuf_new()) == NULL) 1558 fatal("%s: sshbuf_new failed", __func__); 1559 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1560 child_state); 1561 debug3("%s: GOT new keys", __func__); 1562 } 1563 1564 1565 /* XXX */ 1566 1567 #define FD_CLOSEONEXEC(x) do { \ 1568 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1569 fatal("fcntl(%d, F_SETFD)", x); \ 1570 } while (0) 1571 1572 static void 1573 monitor_openfds(struct monitor *mon, int do_logfds) 1574 { 1575 int pair[2]; 1576 1577 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1578 fatal("%s: socketpair: %s", __func__, strerror(errno)); 1579 FD_CLOSEONEXEC(pair[0]); 1580 FD_CLOSEONEXEC(pair[1]); 1581 mon->m_recvfd = pair[0]; 1582 mon->m_sendfd = pair[1]; 1583 1584 if (do_logfds) { 1585 if (pipe(pair) == -1) 1586 fatal("%s: pipe: %s", __func__, strerror(errno)); 1587 FD_CLOSEONEXEC(pair[0]); 1588 FD_CLOSEONEXEC(pair[1]); 1589 mon->m_log_recvfd = pair[0]; 1590 mon->m_log_sendfd = pair[1]; 1591 } else 1592 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1593 } 1594 1595 #define MM_MEMSIZE 65536 1596 1597 struct monitor * 1598 monitor_init(void) 1599 { 1600 struct ssh *ssh = active_state; /* XXX */ 1601 struct monitor *mon; 1602 1603 mon = xcalloc(1, sizeof(*mon)); 1604 1605 monitor_openfds(mon, 1); 1606 1607 /* Used to share zlib space across processes */ 1608 if (options.compression) { 1609 mon->m_zback = mm_create(NULL, MM_MEMSIZE); 1610 mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE); 1611 1612 /* Compression needs to share state across borders */ 1613 ssh_packet_set_compress_hooks(ssh, mon->m_zlib, 1614 (ssh_packet_comp_alloc_func *)mm_zalloc, 1615 (ssh_packet_comp_free_func *)mm_zfree); 1616 } 1617 1618 return mon; 1619 } 1620 1621 void 1622 monitor_reinit(struct monitor *mon) 1623 { 1624 monitor_openfds(mon, 0); 1625 } 1626 1627 #ifdef GSSAPI 1628 int 1629 mm_answer_gss_setup_ctx(int sock, Buffer *m) 1630 { 1631 gss_OID_desc goid; 1632 OM_uint32 major; 1633 u_int len; 1634 1635 goid.elements = buffer_get_string(m, &len); 1636 goid.length = len; 1637 1638 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1639 1640 free(goid.elements); 1641 1642 buffer_clear(m); 1643 buffer_put_int(m, major); 1644 1645 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1646 1647 /* Now we have a context, enable the step */ 1648 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1649 1650 return (0); 1651 } 1652 1653 int 1654 mm_answer_gss_accept_ctx(int sock, Buffer *m) 1655 { 1656 gss_buffer_desc in; 1657 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1658 OM_uint32 major, minor; 1659 OM_uint32 flags = 0; /* GSI needs this */ 1660 u_int len; 1661 1662 in.value = buffer_get_string(m, &len); 1663 in.length = len; 1664 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1665 free(in.value); 1666 1667 buffer_clear(m); 1668 buffer_put_int(m, major); 1669 buffer_put_string(m, out.value, out.length); 1670 buffer_put_int(m, flags); 1671 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1672 1673 gss_release_buffer(&minor, &out); 1674 1675 if (major == GSS_S_COMPLETE) { 1676 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1677 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1678 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1679 } 1680 return (0); 1681 } 1682 1683 int 1684 mm_answer_gss_checkmic(int sock, Buffer *m) 1685 { 1686 gss_buffer_desc gssbuf, mic; 1687 OM_uint32 ret; 1688 u_int len; 1689 1690 gssbuf.value = buffer_get_string(m, &len); 1691 gssbuf.length = len; 1692 mic.value = buffer_get_string(m, &len); 1693 mic.length = len; 1694 1695 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1696 1697 free(gssbuf.value); 1698 free(mic.value); 1699 1700 buffer_clear(m); 1701 buffer_put_int(m, ret); 1702 1703 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1704 1705 if (!GSS_ERROR(ret)) 1706 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1707 1708 return (0); 1709 } 1710 1711 int 1712 mm_answer_gss_userok(int sock, Buffer *m) 1713 { 1714 int authenticated; 1715 1716 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1717 1718 buffer_clear(m); 1719 buffer_put_int(m, authenticated); 1720 1721 debug3("%s: sending result %d", __func__, authenticated); 1722 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1723 1724 auth_method = "gssapi-with-mic"; 1725 1726 /* Monitor loop will terminate if authenticated */ 1727 return (authenticated); 1728 } 1729 #endif /* GSSAPI */ 1730 1731