monitor.c revision 323136
1/* $OpenBSD: monitor.c,v 1.167 2017/02/03 23:05:57 djm Exp $ */ 2/* 3 * Copyright 2002 Niels Provos <provos@citi.umich.edu> 4 * Copyright 2002 Markus Friedl <markus@openbsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28#include "includes.h" 29 30#include <sys/types.h> 31#include <sys/socket.h> 32#include "openbsd-compat/sys-tree.h" 33#include <sys/wait.h> 34 35#include <errno.h> 36#include <fcntl.h> 37#include <limits.h> 38#ifdef HAVE_PATHS_H 39#include <paths.h> 40#endif 41#include <pwd.h> 42#include <signal.h> 43#ifdef HAVE_STDINT_H 44#include <stdint.h> 45#endif 46#include <stdlib.h> 47#include <string.h> 48#include <stdarg.h> 49#include <stdio.h> 50#include <unistd.h> 51#ifdef HAVE_POLL_H 52#include <poll.h> 53#else 54# ifdef HAVE_SYS_POLL_H 55# include <sys/poll.h> 56# endif 57#endif 58 59#ifdef SKEY 60#include <skey.h> 61#endif 62 63#ifdef WITH_OPENSSL 64#include <openssl/dh.h> 65#endif 66 67#include "openbsd-compat/sys-queue.h" 68#include "atomicio.h" 69#include "xmalloc.h" 70#include "ssh.h" 71#include "key.h" 72#include "buffer.h" 73#include "hostfile.h" 74#include "auth.h" 75#include "cipher.h" 76#include "kex.h" 77#include "dh.h" 78#include "auth-pam.h" 79#ifdef TARGET_OS_MAC /* XXX Broken krb5 headers on Mac */ 80#undef TARGET_OS_MAC 81#include "zlib.h" 82#define TARGET_OS_MAC 1 83#else 84#include "zlib.h" 85#endif 86#include "packet.h" 87#include "auth-options.h" 88#include "sshpty.h" 89#include "channels.h" 90#include "session.h" 91#include "sshlogin.h" 92#include "canohost.h" 93#include "log.h" 94#include "misc.h" 95#include "servconf.h" 96#include "monitor.h" 97#ifdef GSSAPI 98#include "ssh-gss.h" 99#endif 100#include "monitor_wrap.h" 101#include "monitor_fdpass.h" 102#include "compat.h" 103#include "ssh2.h" 104#include "authfd.h" 105#include "match.h" 106#include "ssherr.h" 107 108#ifdef GSSAPI 109static Gssctxt *gsscontext = NULL; 110#endif 111 112/* Imports */ 113extern ServerOptions options; 114extern u_int utmp_len; 115extern u_char session_id[]; 116extern Buffer auth_debug; 117extern int auth_debug_init; 118extern Buffer loginmsg; 119 120/* State exported from the child */ 121static struct sshbuf *child_state; 122 123/* Functions on the monitor that answer unprivileged requests */ 124 125int mm_answer_moduli(int, Buffer *); 126int mm_answer_sign(int, Buffer *); 127int mm_answer_pwnamallow(int, Buffer *); 128int mm_answer_auth2_read_banner(int, Buffer *); 129int mm_answer_authserv(int, Buffer *); 130int mm_answer_authpassword(int, Buffer *); 131int mm_answer_bsdauthquery(int, Buffer *); 132int mm_answer_bsdauthrespond(int, Buffer *); 133int mm_answer_skeyquery(int, Buffer *); 134int mm_answer_skeyrespond(int, Buffer *); 135int mm_answer_keyallowed(int, Buffer *); 136int mm_answer_keyverify(int, Buffer *); 137int mm_answer_pty(int, Buffer *); 138int mm_answer_pty_cleanup(int, Buffer *); 139int mm_answer_term(int, Buffer *); 140int mm_answer_rsa_keyallowed(int, Buffer *); 141int mm_answer_rsa_challenge(int, Buffer *); 142int mm_answer_rsa_response(int, Buffer *); 143int mm_answer_sesskey(int, Buffer *); 144int mm_answer_sessid(int, Buffer *); 145 146#ifdef USE_PAM 147int mm_answer_pam_start(int, Buffer *); 148int mm_answer_pam_account(int, Buffer *); 149int mm_answer_pam_init_ctx(int, Buffer *); 150int mm_answer_pam_query(int, Buffer *); 151int mm_answer_pam_respond(int, Buffer *); 152int mm_answer_pam_free_ctx(int, Buffer *); 153#endif 154 155#ifdef GSSAPI 156int mm_answer_gss_setup_ctx(int, Buffer *); 157int mm_answer_gss_accept_ctx(int, Buffer *); 158int mm_answer_gss_userok(int, Buffer *); 159int mm_answer_gss_checkmic(int, Buffer *); 160#endif 161 162#ifdef SSH_AUDIT_EVENTS 163int mm_answer_audit_event(int, Buffer *); 164int mm_answer_audit_command(int, Buffer *); 165#endif 166 167static int monitor_read_log(struct monitor *); 168 169static Authctxt *authctxt; 170 171/* local state for key verify */ 172static u_char *key_blob = NULL; 173static u_int key_bloblen = 0; 174static int key_blobtype = MM_NOKEY; 175static char *hostbased_cuser = NULL; 176static char *hostbased_chost = NULL; 177static char *auth_method = "unknown"; 178static char *auth_submethod = NULL; 179static u_int session_id2_len = 0; 180static u_char *session_id2 = NULL; 181static pid_t monitor_child_pid; 182 183struct mon_table { 184 enum monitor_reqtype type; 185 int flags; 186 int (*f)(int, Buffer *); 187}; 188 189#define MON_ISAUTH 0x0004 /* Required for Authentication */ 190#define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 191#define MON_ONCE 0x0010 /* Disable after calling */ 192#define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 193 194#define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 195 196#define MON_PERMIT 0x1000 /* Request is permitted */ 197 198struct mon_table mon_dispatch_proto20[] = { 199#ifdef WITH_OPENSSL 200 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 201#endif 202 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 203 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 204 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 205 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 206 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 207#ifdef USE_PAM 208 {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start}, 209 {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account}, 210 {MONITOR_REQ_PAM_INIT_CTX, MON_ONCE, mm_answer_pam_init_ctx}, 211 {MONITOR_REQ_PAM_QUERY, 0, mm_answer_pam_query}, 212 {MONITOR_REQ_PAM_RESPOND, MON_ONCE, mm_answer_pam_respond}, 213 {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx}, 214#endif 215#ifdef SSH_AUDIT_EVENTS 216 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 217#endif 218#ifdef BSD_AUTH 219 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 220 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 221#endif 222#ifdef SKEY 223 {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery}, 224 {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond}, 225#endif 226 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 227 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 228#ifdef GSSAPI 229 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 230 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx}, 231 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok}, 232 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic}, 233#endif 234 {0, 0, NULL} 235}; 236 237struct mon_table mon_dispatch_postauth20[] = { 238#ifdef WITH_OPENSSL 239 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 240#endif 241 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 242 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 243 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 244 {MONITOR_REQ_TERM, 0, mm_answer_term}, 245#ifdef SSH_AUDIT_EVENTS 246 {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event}, 247 {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command}, 248#endif 249 {0, 0, NULL} 250}; 251 252struct mon_table *mon_dispatch; 253 254/* Specifies if a certain message is allowed at the moment */ 255 256static void 257monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 258{ 259 while (ent->f != NULL) { 260 if (ent->type == type) { 261 ent->flags &= ~MON_PERMIT; 262 ent->flags |= permit ? MON_PERMIT : 0; 263 return; 264 } 265 ent++; 266 } 267} 268 269static void 270monitor_permit_authentications(int permit) 271{ 272 struct mon_table *ent = mon_dispatch; 273 274 while (ent->f != NULL) { 275 if (ent->flags & MON_AUTH) { 276 ent->flags &= ~MON_PERMIT; 277 ent->flags |= permit ? MON_PERMIT : 0; 278 } 279 ent++; 280 } 281} 282 283void 284monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor) 285{ 286 struct ssh *ssh = active_state; /* XXX */ 287 struct mon_table *ent; 288 int authenticated = 0, partial = 0; 289 290 debug3("preauth child monitor started"); 291 292 close(pmonitor->m_recvfd); 293 close(pmonitor->m_log_sendfd); 294 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 295 296 authctxt = _authctxt; 297 memset(authctxt, 0, sizeof(*authctxt)); 298 299 authctxt->loginmsg = &loginmsg; 300 301 mon_dispatch = mon_dispatch_proto20; 302 /* Permit requests for moduli and signatures */ 303 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 304 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 305 306 /* The first few requests do not require asynchronous access */ 307 while (!authenticated) { 308 partial = 0; 309 auth_method = "unknown"; 310 auth_submethod = NULL; 311 authenticated = (monitor_read(pmonitor, mon_dispatch, &ent) == 1); 312 313 /* Special handling for multiple required authentications */ 314 if (options.num_auth_methods != 0) { 315 if (authenticated && 316 !auth2_update_methods_lists(authctxt, 317 auth_method, auth_submethod)) { 318 debug3("%s: method %s: partial", __func__, 319 auth_method); 320 authenticated = 0; 321 partial = 1; 322 } 323 } 324 325 if (authenticated) { 326 if (!(ent->flags & MON_AUTHDECIDE)) 327 fatal("%s: unexpected authentication from %d", 328 __func__, ent->type); 329 if (authctxt->pw->pw_uid == 0 && 330 !auth_root_allowed(auth_method)) 331 authenticated = 0; 332#ifdef USE_PAM 333 /* PAM needs to perform account checks after auth */ 334 if (options.use_pam && authenticated) { 335 Buffer m; 336 337 buffer_init(&m); 338 mm_request_receive_expect(pmonitor->m_sendfd, 339 MONITOR_REQ_PAM_ACCOUNT, &m); 340 authenticated = mm_answer_pam_account(pmonitor->m_sendfd, &m); 341 buffer_free(&m); 342 } 343#endif 344 } 345 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 346 auth_log(authctxt, authenticated, partial, 347 auth_method, auth_submethod); 348 if (!partial && !authenticated) 349 authctxt->failures++; 350 } 351 } 352 353 if (!authctxt->valid) 354 fatal("%s: authenticated invalid user", __func__); 355 if (strcmp(auth_method, "unknown") == 0) 356 fatal("%s: authentication method name unknown", __func__); 357 358 debug("%s: %s has been authenticated by privileged process", 359 __func__, authctxt->user); 360 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 361 362 mm_get_keystate(pmonitor); 363 364 /* Drain any buffered messages from the child */ 365 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 366 ; 367 368 close(pmonitor->m_sendfd); 369 close(pmonitor->m_log_recvfd); 370 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 371} 372 373static void 374monitor_set_child_handler(pid_t pid) 375{ 376 monitor_child_pid = pid; 377} 378 379static void 380monitor_child_handler(int sig) 381{ 382 kill(monitor_child_pid, sig); 383} 384 385void 386monitor_child_postauth(struct monitor *pmonitor) 387{ 388 close(pmonitor->m_recvfd); 389 pmonitor->m_recvfd = -1; 390 391 monitor_set_child_handler(pmonitor->m_pid); 392 signal(SIGHUP, &monitor_child_handler); 393 signal(SIGTERM, &monitor_child_handler); 394 signal(SIGINT, &monitor_child_handler); 395#ifdef SIGXFSZ 396 signal(SIGXFSZ, SIG_IGN); 397#endif 398 399 mon_dispatch = mon_dispatch_postauth20; 400 401 /* Permit requests for moduli and signatures */ 402 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 403 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 404 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 405 406 if (!no_pty_flag) { 407 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 408 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 409 } 410 411 for (;;) 412 monitor_read(pmonitor, mon_dispatch, NULL); 413} 414 415static int 416monitor_read_log(struct monitor *pmonitor) 417{ 418 Buffer logmsg; 419 u_int len, level; 420 char *msg; 421 422 buffer_init(&logmsg); 423 424 /* Read length */ 425 buffer_append_space(&logmsg, 4); 426 if (atomicio(read, pmonitor->m_log_recvfd, 427 buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) { 428 if (errno == EPIPE) { 429 buffer_free(&logmsg); 430 debug("%s: child log fd closed", __func__); 431 close(pmonitor->m_log_recvfd); 432 pmonitor->m_log_recvfd = -1; 433 return -1; 434 } 435 fatal("%s: log fd read: %s", __func__, strerror(errno)); 436 } 437 len = buffer_get_int(&logmsg); 438 if (len <= 4 || len > 8192) 439 fatal("%s: invalid log message length %u", __func__, len); 440 441 /* Read severity, message */ 442 buffer_clear(&logmsg); 443 buffer_append_space(&logmsg, len); 444 if (atomicio(read, pmonitor->m_log_recvfd, 445 buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) 446 fatal("%s: log fd read: %s", __func__, strerror(errno)); 447 448 /* Log it */ 449 level = buffer_get_int(&logmsg); 450 msg = buffer_get_string(&logmsg, NULL); 451 if (log_level_name(level) == NULL) 452 fatal("%s: invalid log level %u (corrupted message?)", 453 __func__, level); 454 do_log2(level, "%s [preauth]", msg); 455 456 buffer_free(&logmsg); 457 free(msg); 458 459 return 0; 460} 461 462int 463monitor_read(struct monitor *pmonitor, struct mon_table *ent, 464 struct mon_table **pent) 465{ 466 Buffer m; 467 int ret; 468 u_char type; 469 struct pollfd pfd[2]; 470 471 for (;;) { 472 memset(&pfd, 0, sizeof(pfd)); 473 pfd[0].fd = pmonitor->m_sendfd; 474 pfd[0].events = POLLIN; 475 pfd[1].fd = pmonitor->m_log_recvfd; 476 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 477 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 478 if (errno == EINTR || errno == EAGAIN) 479 continue; 480 fatal("%s: poll: %s", __func__, strerror(errno)); 481 } 482 if (pfd[1].revents) { 483 /* 484 * Drain all log messages before processing next 485 * monitor request. 486 */ 487 monitor_read_log(pmonitor); 488 continue; 489 } 490 if (pfd[0].revents) 491 break; /* Continues below */ 492 } 493 494 buffer_init(&m); 495 496 mm_request_receive(pmonitor->m_sendfd, &m); 497 type = buffer_get_char(&m); 498 499 debug3("%s: checking request %d", __func__, type); 500 501 while (ent->f != NULL) { 502 if (ent->type == type) 503 break; 504 ent++; 505 } 506 507 if (ent->f != NULL) { 508 if (!(ent->flags & MON_PERMIT)) 509 fatal("%s: unpermitted request %d", __func__, 510 type); 511 ret = (*ent->f)(pmonitor->m_sendfd, &m); 512 buffer_free(&m); 513 514 /* The child may use this request only once, disable it */ 515 if (ent->flags & MON_ONCE) { 516 debug2("%s: %d used once, disabling now", __func__, 517 type); 518 ent->flags &= ~MON_PERMIT; 519 } 520 521 if (pent != NULL) 522 *pent = ent; 523 524 return ret; 525 } 526 527 fatal("%s: unsupported request: %d", __func__, type); 528 529 /* NOTREACHED */ 530 return (-1); 531} 532 533/* allowed key state */ 534static int 535monitor_allowed_key(u_char *blob, u_int bloblen) 536{ 537 /* make sure key is allowed */ 538 if (key_blob == NULL || key_bloblen != bloblen || 539 timingsafe_bcmp(key_blob, blob, key_bloblen)) 540 return (0); 541 return (1); 542} 543 544static void 545monitor_reset_key_state(void) 546{ 547 /* reset state */ 548 free(key_blob); 549 free(hostbased_cuser); 550 free(hostbased_chost); 551 key_blob = NULL; 552 key_bloblen = 0; 553 key_blobtype = MM_NOKEY; 554 hostbased_cuser = NULL; 555 hostbased_chost = NULL; 556} 557 558#ifdef WITH_OPENSSL 559int 560mm_answer_moduli(int sock, Buffer *m) 561{ 562 DH *dh; 563 int min, want, max; 564 565 min = buffer_get_int(m); 566 want = buffer_get_int(m); 567 max = buffer_get_int(m); 568 569 debug3("%s: got parameters: %d %d %d", 570 __func__, min, want, max); 571 /* We need to check here, too, in case the child got corrupted */ 572 if (max < min || want < min || max < want) 573 fatal("%s: bad parameters: %d %d %d", 574 __func__, min, want, max); 575 576 buffer_clear(m); 577 578 dh = choose_dh(min, want, max); 579 if (dh == NULL) { 580 buffer_put_char(m, 0); 581 return (0); 582 } else { 583 /* Send first bignum */ 584 buffer_put_char(m, 1); 585 buffer_put_bignum2(m, dh->p); 586 buffer_put_bignum2(m, dh->g); 587 588 DH_free(dh); 589 } 590 mm_request_send(sock, MONITOR_ANS_MODULI, m); 591 return (0); 592} 593#endif 594 595int 596mm_answer_sign(int sock, Buffer *m) 597{ 598 struct ssh *ssh = active_state; /* XXX */ 599 extern int auth_sock; /* XXX move to state struct? */ 600 struct sshkey *key; 601 struct sshbuf *sigbuf = NULL; 602 u_char *p = NULL, *signature = NULL; 603 char *alg = NULL; 604 size_t datlen, siglen, alglen; 605 int r, is_proof = 0; 606 u_int keyid; 607 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 608 609 debug3("%s", __func__); 610 611 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 612 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 613 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0) 614 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 615 if (keyid > INT_MAX) 616 fatal("%s: invalid key ID", __func__); 617 618 /* 619 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 620 * SHA384 (48 bytes) and SHA512 (64 bytes). 621 * 622 * Otherwise, verify the signature request is for a hostkey 623 * proof. 624 * 625 * XXX perform similar check for KEX signature requests too? 626 * it's not trivial, since what is signed is the hash, rather 627 * than the full kex structure... 628 */ 629 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 630 /* 631 * Construct expected hostkey proof and compare it to what 632 * the client sent us. 633 */ 634 if (session_id2_len == 0) /* hostkeys is never first */ 635 fatal("%s: bad data length: %zu", __func__, datlen); 636 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 637 fatal("%s: no hostkey for index %d", __func__, keyid); 638 if ((sigbuf = sshbuf_new()) == NULL) 639 fatal("%s: sshbuf_new", __func__); 640 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 641 (r = sshbuf_put_string(sigbuf, session_id2, 642 session_id2_len)) != 0 || 643 (r = sshkey_puts(key, sigbuf)) != 0) 644 fatal("%s: couldn't prepare private key " 645 "proof buffer: %s", __func__, ssh_err(r)); 646 if (datlen != sshbuf_len(sigbuf) || 647 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 648 fatal("%s: bad data length: %zu, hostkey proof len %zu", 649 __func__, datlen, sshbuf_len(sigbuf)); 650 sshbuf_free(sigbuf); 651 is_proof = 1; 652 } 653 654 /* save session id, it will be passed on the first call */ 655 if (session_id2_len == 0) { 656 session_id2_len = datlen; 657 session_id2 = xmalloc(session_id2_len); 658 memcpy(session_id2, p, session_id2_len); 659 } 660 661 if ((key = get_hostkey_by_index(keyid)) != NULL) { 662 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 663 datafellows)) != 0) 664 fatal("%s: sshkey_sign failed: %s", 665 __func__, ssh_err(r)); 666 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 667 auth_sock > 0) { 668 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 669 p, datlen, alg, datafellows)) != 0) { 670 fatal("%s: ssh_agent_sign failed: %s", 671 __func__, ssh_err(r)); 672 } 673 } else 674 fatal("%s: no hostkey from index %d", __func__, keyid); 675 676 debug3("%s: %s signature %p(%zu)", __func__, 677 is_proof ? "KEX" : "hostkey proof", signature, siglen); 678 679 sshbuf_reset(m); 680 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 681 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 682 683 free(alg); 684 free(p); 685 free(signature); 686 687 mm_request_send(sock, MONITOR_ANS_SIGN, m); 688 689 /* Turn on permissions for getpwnam */ 690 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 691 692 return (0); 693} 694 695/* Retrieves the password entry and also checks if the user is permitted */ 696 697int 698mm_answer_pwnamallow(int sock, Buffer *m) 699{ 700 struct ssh *ssh = active_state; /* XXX */ 701 char *username; 702 struct passwd *pwent; 703 int allowed = 0; 704 u_int i; 705 706 debug3("%s", __func__); 707 708 if (authctxt->attempt++ != 0) 709 fatal("%s: multiple attempts for getpwnam", __func__); 710 711 username = buffer_get_string(m, NULL); 712 713 pwent = getpwnamallow(username); 714 715 authctxt->user = xstrdup(username); 716 setproctitle("%s [priv]", pwent ? username : "unknown"); 717 free(username); 718 719 buffer_clear(m); 720 721 if (pwent == NULL) { 722 buffer_put_char(m, 0); 723 authctxt->pw = fakepw(); 724 goto out; 725 } 726 727 allowed = 1; 728 authctxt->pw = pwent; 729 authctxt->valid = 1; 730 731 buffer_put_char(m, 1); 732 buffer_put_string(m, pwent, sizeof(struct passwd)); 733 buffer_put_cstring(m, pwent->pw_name); 734 buffer_put_cstring(m, "*"); 735#ifdef HAVE_STRUCT_PASSWD_PW_GECOS 736 buffer_put_cstring(m, pwent->pw_gecos); 737#endif 738#ifdef HAVE_STRUCT_PASSWD_PW_CLASS 739 buffer_put_cstring(m, pwent->pw_class); 740#endif 741 buffer_put_cstring(m, pwent->pw_dir); 742 buffer_put_cstring(m, pwent->pw_shell); 743 744 out: 745 ssh_packet_set_log_preamble(ssh, "%suser %s", 746 authctxt->valid ? "authenticating" : "invalid ", authctxt->user); 747 buffer_put_string(m, &options, sizeof(options)); 748 749#define M_CP_STROPT(x) do { \ 750 if (options.x != NULL) \ 751 buffer_put_cstring(m, options.x); \ 752 } while (0) 753#define M_CP_STRARRAYOPT(x, nx) do { \ 754 for (i = 0; i < options.nx; i++) \ 755 buffer_put_cstring(m, options.x[i]); \ 756 } while (0) 757 /* See comment in servconf.h */ 758 COPY_MATCH_STRING_OPTS(); 759#undef M_CP_STROPT 760#undef M_CP_STRARRAYOPT 761 762 /* Create valid auth method lists */ 763 if (auth2_setup_methods_lists(authctxt) != 0) { 764 /* 765 * The monitor will continue long enough to let the child 766 * run to it's packet_disconnect(), but it must not allow any 767 * authentication to succeed. 768 */ 769 debug("%s: no valid authentication method lists", __func__); 770 } 771 772 debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed); 773 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 774 775 /* Allow service/style information on the auth context */ 776 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 777 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 778 779#ifdef USE_PAM 780 if (options.use_pam) 781 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); 782#endif 783 784 return (0); 785} 786 787int mm_answer_auth2_read_banner(int sock, Buffer *m) 788{ 789 char *banner; 790 791 buffer_clear(m); 792 banner = auth2_read_banner(); 793 buffer_put_cstring(m, banner != NULL ? banner : ""); 794 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 795 free(banner); 796 797 return (0); 798} 799 800int 801mm_answer_authserv(int sock, Buffer *m) 802{ 803 monitor_permit_authentications(1); 804 805 authctxt->service = buffer_get_string(m, NULL); 806 authctxt->style = buffer_get_string(m, NULL); 807 debug3("%s: service=%s, style=%s", 808 __func__, authctxt->service, authctxt->style); 809 810 if (strlen(authctxt->style) == 0) { 811 free(authctxt->style); 812 authctxt->style = NULL; 813 } 814 815 return (0); 816} 817 818int 819mm_answer_authpassword(int sock, Buffer *m) 820{ 821 static int call_count; 822 char *passwd; 823 int authenticated; 824 u_int plen; 825 826 if (!options.password_authentication) 827 fatal("%s: password authentication not enabled", __func__); 828 passwd = buffer_get_string(m, &plen); 829 /* Only authenticate if the context is valid */ 830 authenticated = options.password_authentication && 831 auth_password(authctxt, passwd); 832 explicit_bzero(passwd, strlen(passwd)); 833 free(passwd); 834 835 buffer_clear(m); 836 buffer_put_int(m, authenticated); 837#ifdef USE_PAM 838 buffer_put_int(m, sshpam_get_maxtries_reached()); 839#endif 840 841 debug3("%s: sending result %d", __func__, authenticated); 842 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 843 844 call_count++; 845 if (plen == 0 && call_count == 1) 846 auth_method = "none"; 847 else 848 auth_method = "password"; 849 850 /* Causes monitor loop to terminate if authenticated */ 851 return (authenticated); 852} 853 854#ifdef BSD_AUTH 855int 856mm_answer_bsdauthquery(int sock, Buffer *m) 857{ 858 char *name, *infotxt; 859 u_int numprompts; 860 u_int *echo_on; 861 char **prompts; 862 u_int success; 863 864 if (!options.kbd_interactive_authentication) 865 fatal("%s: kbd-int authentication not enabled", __func__); 866 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 867 &prompts, &echo_on) < 0 ? 0 : 1; 868 869 buffer_clear(m); 870 buffer_put_int(m, success); 871 if (success) 872 buffer_put_cstring(m, prompts[0]); 873 874 debug3("%s: sending challenge success: %u", __func__, success); 875 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 876 877 if (success) { 878 free(name); 879 free(infotxt); 880 free(prompts); 881 free(echo_on); 882 } 883 884 return (0); 885} 886 887int 888mm_answer_bsdauthrespond(int sock, Buffer *m) 889{ 890 char *response; 891 int authok; 892 893 if (!options.kbd_interactive_authentication) 894 fatal("%s: kbd-int authentication not enabled", __func__); 895 if (authctxt->as == NULL) 896 fatal("%s: no bsd auth session", __func__); 897 898 response = buffer_get_string(m, NULL); 899 authok = options.challenge_response_authentication && 900 auth_userresponse(authctxt->as, response, 0); 901 authctxt->as = NULL; 902 debug3("%s: <%s> = <%d>", __func__, response, authok); 903 free(response); 904 905 buffer_clear(m); 906 buffer_put_int(m, authok); 907 908 debug3("%s: sending authenticated: %d", __func__, authok); 909 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 910 911 auth_method = "keyboard-interactive"; 912 auth_submethod = "bsdauth"; 913 914 return (authok != 0); 915} 916#endif 917 918#ifdef SKEY 919int 920mm_answer_skeyquery(int sock, Buffer *m) 921{ 922 struct skey skey; 923 char challenge[1024]; 924 u_int success; 925 926 success = _compat_skeychallenge(&skey, authctxt->user, challenge, 927 sizeof(challenge)) < 0 ? 0 : 1; 928 929 buffer_clear(m); 930 buffer_put_int(m, success); 931 if (success) 932 buffer_put_cstring(m, challenge); 933 934 debug3("%s: sending challenge success: %u", __func__, success); 935 mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m); 936 937 return (0); 938} 939 940int 941mm_answer_skeyrespond(int sock, Buffer *m) 942{ 943 char *response; 944 int authok; 945 946 response = buffer_get_string(m, NULL); 947 948 authok = (options.challenge_response_authentication && 949 authctxt->valid && 950 skey_haskey(authctxt->pw->pw_name) == 0 && 951 skey_passcheck(authctxt->pw->pw_name, response) != -1); 952 953 free(response); 954 955 buffer_clear(m); 956 buffer_put_int(m, authok); 957 958 debug3("%s: sending authenticated: %d", __func__, authok); 959 mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m); 960 961 auth_method = "keyboard-interactive"; 962 auth_submethod = "skey"; 963 964 return (authok != 0); 965} 966#endif 967 968#ifdef USE_PAM 969int 970mm_answer_pam_start(int sock, Buffer *m) 971{ 972 if (!options.use_pam) 973 fatal("UsePAM not set, but ended up in %s anyway", __func__); 974 975 start_pam(authctxt); 976 977 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1); 978 if (options.kbd_interactive_authentication) 979 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 980 981 return (0); 982} 983 984int 985mm_answer_pam_account(int sock, Buffer *m) 986{ 987 u_int ret; 988 989 if (!options.use_pam) 990 fatal("%s: PAM not enabled", __func__); 991 992 ret = do_pam_account(); 993 994 buffer_put_int(m, ret); 995 buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg)); 996 997 mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m); 998 999 return (ret); 1000} 1001 1002static void *sshpam_ctxt, *sshpam_authok; 1003extern KbdintDevice sshpam_device; 1004 1005int 1006mm_answer_pam_init_ctx(int sock, Buffer *m) 1007{ 1008 debug3("%s", __func__); 1009 if (!options.kbd_interactive_authentication) 1010 fatal("%s: kbd-int authentication not enabled", __func__); 1011 if (sshpam_ctxt != NULL) 1012 fatal("%s: already called", __func__); 1013 sshpam_ctxt = (sshpam_device.init_ctx)(authctxt); 1014 sshpam_authok = NULL; 1015 buffer_clear(m); 1016 if (sshpam_ctxt != NULL) { 1017 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1); 1018 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_QUERY, 1); 1019 buffer_put_int(m, 1); 1020 } else { 1021 buffer_put_int(m, 0); 1022 } 1023 mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m); 1024 return (0); 1025} 1026 1027int 1028mm_answer_pam_query(int sock, Buffer *m) 1029{ 1030 char *name = NULL, *info = NULL, **prompts = NULL; 1031 u_int i, num = 0, *echo_on = 0; 1032 int ret; 1033 1034 debug3("%s", __func__); 1035 sshpam_authok = NULL; 1036 if (sshpam_ctxt == NULL) 1037 fatal("%s: no context", __func__); 1038 ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, 1039 &num, &prompts, &echo_on); 1040 if (ret == 0 && num == 0) 1041 sshpam_authok = sshpam_ctxt; 1042 if (num > 1 || name == NULL || info == NULL) 1043 fatal("sshpam_device.query failed"); 1044 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_RESPOND, 1); 1045 buffer_clear(m); 1046 buffer_put_int(m, ret); 1047 buffer_put_cstring(m, name); 1048 free(name); 1049 buffer_put_cstring(m, info); 1050 free(info); 1051 buffer_put_int(m, sshpam_get_maxtries_reached()); 1052 buffer_put_int(m, num); 1053 for (i = 0; i < num; ++i) { 1054 buffer_put_cstring(m, prompts[i]); 1055 free(prompts[i]); 1056 buffer_put_int(m, echo_on[i]); 1057 } 1058 free(prompts); 1059 free(echo_on); 1060 auth_method = "keyboard-interactive"; 1061 auth_submethod = "pam"; 1062 mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m); 1063 return (0); 1064} 1065 1066int 1067mm_answer_pam_respond(int sock, Buffer *m) 1068{ 1069 char **resp; 1070 u_int i, num; 1071 int ret; 1072 1073 debug3("%s", __func__); 1074 if (sshpam_ctxt == NULL) 1075 fatal("%s: no context", __func__); 1076 sshpam_authok = NULL; 1077 num = buffer_get_int(m); 1078 if (num > 0) { 1079 resp = xcalloc(num, sizeof(char *)); 1080 for (i = 0; i < num; ++i) 1081 resp[i] = buffer_get_string(m, NULL); 1082 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp); 1083 for (i = 0; i < num; ++i) 1084 free(resp[i]); 1085 free(resp); 1086 } else { 1087 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL); 1088 } 1089 buffer_clear(m); 1090 buffer_put_int(m, ret); 1091 mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m); 1092 auth_method = "keyboard-interactive"; 1093 auth_submethod = "pam"; 1094 if (ret == 0) 1095 sshpam_authok = sshpam_ctxt; 1096 return (0); 1097} 1098 1099int 1100mm_answer_pam_free_ctx(int sock, Buffer *m) 1101{ 1102 int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt; 1103 1104 debug3("%s", __func__); 1105 if (sshpam_ctxt == NULL) 1106 fatal("%s: no context", __func__); 1107 (sshpam_device.free_ctx)(sshpam_ctxt); 1108 sshpam_ctxt = sshpam_authok = NULL; 1109 buffer_clear(m); 1110 mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m); 1111 /* Allow another attempt */ 1112 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_INIT_CTX, 1); 1113 auth_method = "keyboard-interactive"; 1114 auth_submethod = "pam"; 1115 return r; 1116} 1117#endif 1118 1119int 1120mm_answer_keyallowed(int sock, Buffer *m) 1121{ 1122 Key *key; 1123 char *cuser, *chost; 1124 u_char *blob; 1125 u_int bloblen, pubkey_auth_attempt; 1126 enum mm_keytype type = 0; 1127 int allowed = 0; 1128 1129 debug3("%s entering", __func__); 1130 1131 type = buffer_get_int(m); 1132 cuser = buffer_get_string(m, NULL); 1133 chost = buffer_get_string(m, NULL); 1134 blob = buffer_get_string(m, &bloblen); 1135 pubkey_auth_attempt = buffer_get_int(m); 1136 1137 key = key_from_blob(blob, bloblen); 1138 1139 debug3("%s: key_from_blob: %p", __func__, key); 1140 1141 if (key != NULL && authctxt->valid) { 1142 /* These should not make it past the privsep child */ 1143 if (key_type_plain(key->type) == KEY_RSA && 1144 (datafellows & SSH_BUG_RSASIGMD5) != 0) 1145 fatal("%s: passed a SSH_BUG_RSASIGMD5 key", __func__); 1146 1147 switch (type) { 1148 case MM_USERKEY: 1149 allowed = options.pubkey_authentication && 1150 !auth2_userkey_already_used(authctxt, key) && 1151 match_pattern_list(sshkey_ssh_name(key), 1152 options.pubkey_key_types, 0) == 1 && 1153 user_key_allowed(authctxt->pw, key, 1154 pubkey_auth_attempt); 1155 pubkey_auth_info(authctxt, key, NULL); 1156 auth_method = "publickey"; 1157 if (options.pubkey_authentication && 1158 (!pubkey_auth_attempt || allowed != 1)) 1159 auth_clear_options(); 1160 break; 1161 case MM_HOSTKEY: 1162 allowed = options.hostbased_authentication && 1163 match_pattern_list(sshkey_ssh_name(key), 1164 options.hostbased_key_types, 0) == 1 && 1165 hostbased_key_allowed(authctxt->pw, 1166 cuser, chost, key); 1167 pubkey_auth_info(authctxt, key, 1168 "client user \"%.100s\", client host \"%.100s\"", 1169 cuser, chost); 1170 auth_method = "hostbased"; 1171 break; 1172 default: 1173 fatal("%s: unknown key type %d", __func__, type); 1174 break; 1175 } 1176 } 1177 1178 debug3("%s: key %p is %s", 1179 __func__, key, allowed ? "allowed" : "not allowed"); 1180 1181 if (key != NULL) 1182 key_free(key); 1183 1184 /* clear temporarily storage (used by verify) */ 1185 monitor_reset_key_state(); 1186 1187 if (allowed) { 1188 /* Save temporarily for comparison in verify */ 1189 key_blob = blob; 1190 key_bloblen = bloblen; 1191 key_blobtype = type; 1192 hostbased_cuser = cuser; 1193 hostbased_chost = chost; 1194 } else { 1195 /* Log failed attempt */ 1196 auth_log(authctxt, 0, 0, auth_method, NULL); 1197 free(blob); 1198 free(cuser); 1199 free(chost); 1200 } 1201 1202 buffer_clear(m); 1203 buffer_put_int(m, allowed); 1204 buffer_put_int(m, forced_command != NULL); 1205 1206 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 1207 1208 return (0); 1209} 1210 1211static int 1212monitor_valid_userblob(u_char *data, u_int datalen) 1213{ 1214 Buffer b; 1215 u_char *p; 1216 char *userstyle, *cp; 1217 u_int len; 1218 int fail = 0; 1219 1220 buffer_init(&b); 1221 buffer_append(&b, data, datalen); 1222 1223 if (datafellows & SSH_OLD_SESSIONID) { 1224 p = buffer_ptr(&b); 1225 len = buffer_len(&b); 1226 if ((session_id2 == NULL) || 1227 (len < session_id2_len) || 1228 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1229 fail++; 1230 buffer_consume(&b, session_id2_len); 1231 } else { 1232 p = buffer_get_string(&b, &len); 1233 if ((session_id2 == NULL) || 1234 (len != session_id2_len) || 1235 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1236 fail++; 1237 free(p); 1238 } 1239 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 1240 fail++; 1241 cp = buffer_get_cstring(&b, NULL); 1242 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1243 authctxt->style ? ":" : "", 1244 authctxt->style ? authctxt->style : ""); 1245 if (strcmp(userstyle, cp) != 0) { 1246 logit("wrong user name passed to monitor: " 1247 "expected %s != %.100s", userstyle, cp); 1248 fail++; 1249 } 1250 free(userstyle); 1251 free(cp); 1252 buffer_skip_string(&b); 1253 if (datafellows & SSH_BUG_PKAUTH) { 1254 if (!buffer_get_char(&b)) 1255 fail++; 1256 } else { 1257 cp = buffer_get_cstring(&b, NULL); 1258 if (strcmp("publickey", cp) != 0) 1259 fail++; 1260 free(cp); 1261 if (!buffer_get_char(&b)) 1262 fail++; 1263 buffer_skip_string(&b); 1264 } 1265 buffer_skip_string(&b); 1266 if (buffer_len(&b) != 0) 1267 fail++; 1268 buffer_free(&b); 1269 return (fail == 0); 1270} 1271 1272static int 1273monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser, 1274 char *chost) 1275{ 1276 Buffer b; 1277 char *p, *userstyle; 1278 u_int len; 1279 int fail = 0; 1280 1281 buffer_init(&b); 1282 buffer_append(&b, data, datalen); 1283 1284 p = buffer_get_string(&b, &len); 1285 if ((session_id2 == NULL) || 1286 (len != session_id2_len) || 1287 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1288 fail++; 1289 free(p); 1290 1291 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 1292 fail++; 1293 p = buffer_get_cstring(&b, NULL); 1294 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1295 authctxt->style ? ":" : "", 1296 authctxt->style ? authctxt->style : ""); 1297 if (strcmp(userstyle, p) != 0) { 1298 logit("wrong user name passed to monitor: expected %s != %.100s", 1299 userstyle, p); 1300 fail++; 1301 } 1302 free(userstyle); 1303 free(p); 1304 buffer_skip_string(&b); /* service */ 1305 p = buffer_get_cstring(&b, NULL); 1306 if (strcmp(p, "hostbased") != 0) 1307 fail++; 1308 free(p); 1309 buffer_skip_string(&b); /* pkalg */ 1310 buffer_skip_string(&b); /* pkblob */ 1311 1312 /* verify client host, strip trailing dot if necessary */ 1313 p = buffer_get_string(&b, NULL); 1314 if (((len = strlen(p)) > 0) && p[len - 1] == '.') 1315 p[len - 1] = '\0'; 1316 if (strcmp(p, chost) != 0) 1317 fail++; 1318 free(p); 1319 1320 /* verify client user */ 1321 p = buffer_get_string(&b, NULL); 1322 if (strcmp(p, cuser) != 0) 1323 fail++; 1324 free(p); 1325 1326 if (buffer_len(&b) != 0) 1327 fail++; 1328 buffer_free(&b); 1329 return (fail == 0); 1330} 1331 1332int 1333mm_answer_keyverify(int sock, Buffer *m) 1334{ 1335 Key *key; 1336 u_char *signature, *data, *blob; 1337 u_int signaturelen, datalen, bloblen; 1338 int verified = 0; 1339 int valid_data = 0; 1340 1341 blob = buffer_get_string(m, &bloblen); 1342 signature = buffer_get_string(m, &signaturelen); 1343 data = buffer_get_string(m, &datalen); 1344 1345 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1346 !monitor_allowed_key(blob, bloblen)) 1347 fatal("%s: bad key, not previously allowed", __func__); 1348 1349 key = key_from_blob(blob, bloblen); 1350 if (key == NULL) 1351 fatal("%s: bad public key blob", __func__); 1352 1353 switch (key_blobtype) { 1354 case MM_USERKEY: 1355 valid_data = monitor_valid_userblob(data, datalen); 1356 break; 1357 case MM_HOSTKEY: 1358 valid_data = monitor_valid_hostbasedblob(data, datalen, 1359 hostbased_cuser, hostbased_chost); 1360 break; 1361 default: 1362 valid_data = 0; 1363 break; 1364 } 1365 if (!valid_data) 1366 fatal("%s: bad signature data blob", __func__); 1367 1368 verified = key_verify(key, signature, signaturelen, data, datalen); 1369 debug3("%s: key %p signature %s", 1370 __func__, key, (verified == 1) ? "verified" : "unverified"); 1371 1372 /* If auth was successful then record key to ensure it isn't reused */ 1373 if (verified == 1 && key_blobtype == MM_USERKEY) 1374 auth2_record_userkey(authctxt, key); 1375 else 1376 key_free(key); 1377 1378 free(blob); 1379 free(signature); 1380 free(data); 1381 1382 auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased"; 1383 1384 monitor_reset_key_state(); 1385 1386 buffer_clear(m); 1387 buffer_put_int(m, verified); 1388 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1389 1390 return (verified == 1); 1391} 1392 1393static void 1394mm_record_login(Session *s, struct passwd *pw) 1395{ 1396 struct ssh *ssh = active_state; /* XXX */ 1397 socklen_t fromlen; 1398 struct sockaddr_storage from; 1399 1400 /* 1401 * Get IP address of client. If the connection is not a socket, let 1402 * the address be 0.0.0.0. 1403 */ 1404 memset(&from, 0, sizeof(from)); 1405 fromlen = sizeof(from); 1406 if (packet_connection_is_on_socket()) { 1407 if (getpeername(packet_get_connection_in(), 1408 (struct sockaddr *)&from, &fromlen) < 0) { 1409 debug("getpeername: %.100s", strerror(errno)); 1410 cleanup_exit(255); 1411 } 1412 } 1413 /* Record that there was a login on that tty from the remote host. */ 1414 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1415 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1416 (struct sockaddr *)&from, fromlen); 1417} 1418 1419static void 1420mm_session_close(Session *s) 1421{ 1422 debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid); 1423 if (s->ttyfd != -1) { 1424 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd); 1425 session_pty_cleanup2(s); 1426 } 1427 session_unused(s->self); 1428} 1429 1430int 1431mm_answer_pty(int sock, Buffer *m) 1432{ 1433 extern struct monitor *pmonitor; 1434 Session *s; 1435 int res, fd0; 1436 1437 debug3("%s entering", __func__); 1438 1439 buffer_clear(m); 1440 s = session_new(); 1441 if (s == NULL) 1442 goto error; 1443 s->authctxt = authctxt; 1444 s->pw = authctxt->pw; 1445 s->pid = pmonitor->m_pid; 1446 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1447 if (res == 0) 1448 goto error; 1449 pty_setowner(authctxt->pw, s->tty); 1450 1451 buffer_put_int(m, 1); 1452 buffer_put_cstring(m, s->tty); 1453 1454 /* We need to trick ttyslot */ 1455 if (dup2(s->ttyfd, 0) == -1) 1456 fatal("%s: dup2", __func__); 1457 1458 mm_record_login(s, authctxt->pw); 1459 1460 /* Now we can close the file descriptor again */ 1461 close(0); 1462 1463 /* send messages generated by record_login */ 1464 buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg)); 1465 buffer_clear(&loginmsg); 1466 1467 mm_request_send(sock, MONITOR_ANS_PTY, m); 1468 1469 if (mm_send_fd(sock, s->ptyfd) == -1 || 1470 mm_send_fd(sock, s->ttyfd) == -1) 1471 fatal("%s: send fds failed", __func__); 1472 1473 /* make sure nothing uses fd 0 */ 1474 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0) 1475 fatal("%s: open(/dev/null): %s", __func__, strerror(errno)); 1476 if (fd0 != 0) 1477 error("%s: fd0 %d != 0", __func__, fd0); 1478 1479 /* slave is not needed */ 1480 close(s->ttyfd); 1481 s->ttyfd = s->ptyfd; 1482 /* no need to dup() because nobody closes ptyfd */ 1483 s->ptymaster = s->ptyfd; 1484 1485 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd); 1486 1487 return (0); 1488 1489 error: 1490 if (s != NULL) 1491 mm_session_close(s); 1492 buffer_put_int(m, 0); 1493 mm_request_send(sock, MONITOR_ANS_PTY, m); 1494 return (0); 1495} 1496 1497int 1498mm_answer_pty_cleanup(int sock, Buffer *m) 1499{ 1500 Session *s; 1501 char *tty; 1502 1503 debug3("%s entering", __func__); 1504 1505 tty = buffer_get_string(m, NULL); 1506 if ((s = session_by_tty(tty)) != NULL) 1507 mm_session_close(s); 1508 buffer_clear(m); 1509 free(tty); 1510 return (0); 1511} 1512 1513int 1514mm_answer_term(int sock, Buffer *req) 1515{ 1516 extern struct monitor *pmonitor; 1517 int res, status; 1518 1519 debug3("%s: tearing down sessions", __func__); 1520 1521 /* The child is terminating */ 1522 session_destroy_all(&mm_session_close); 1523 1524#ifdef USE_PAM 1525 if (options.use_pam) 1526 sshpam_cleanup(); 1527#endif 1528 1529 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1530 if (errno != EINTR) 1531 exit(1); 1532 1533 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1534 1535 /* Terminate process */ 1536 exit(res); 1537} 1538 1539#ifdef SSH_AUDIT_EVENTS 1540/* Report that an audit event occurred */ 1541int 1542mm_answer_audit_event(int socket, Buffer *m) 1543{ 1544 ssh_audit_event_t event; 1545 1546 debug3("%s entering", __func__); 1547 1548 event = buffer_get_int(m); 1549 switch(event) { 1550 case SSH_AUTH_FAIL_PUBKEY: 1551 case SSH_AUTH_FAIL_HOSTBASED: 1552 case SSH_AUTH_FAIL_GSSAPI: 1553 case SSH_LOGIN_EXCEED_MAXTRIES: 1554 case SSH_LOGIN_ROOT_DENIED: 1555 case SSH_CONNECTION_CLOSE: 1556 case SSH_INVALID_USER: 1557 audit_event(event); 1558 break; 1559 default: 1560 fatal("Audit event type %d not permitted", event); 1561 } 1562 1563 return (0); 1564} 1565 1566int 1567mm_answer_audit_command(int socket, Buffer *m) 1568{ 1569 u_int len; 1570 char *cmd; 1571 1572 debug3("%s entering", __func__); 1573 cmd = buffer_get_string(m, &len); 1574 /* sanity check command, if so how? */ 1575 audit_run_command(cmd); 1576 free(cmd); 1577 return (0); 1578} 1579#endif /* SSH_AUDIT_EVENTS */ 1580 1581void 1582monitor_apply_keystate(struct monitor *pmonitor) 1583{ 1584 struct ssh *ssh = active_state; /* XXX */ 1585 struct kex *kex; 1586 int r; 1587 1588 debug3("%s: packet_set_state", __func__); 1589 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1590 fatal("%s: packet_set_state: %s", __func__, ssh_err(r)); 1591 sshbuf_free(child_state); 1592 child_state = NULL; 1593 1594 if ((kex = ssh->kex) != NULL) { 1595 /* XXX set callbacks */ 1596#ifdef WITH_OPENSSL 1597 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; 1598 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; 1599 kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server; 1600 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server; 1601 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server; 1602 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1603 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1604# ifdef OPENSSL_HAS_ECC 1605 kex->kex[KEX_ECDH_SHA2] = kexecdh_server; 1606# endif 1607#endif /* WITH_OPENSSL */ 1608 kex->kex[KEX_C25519_SHA256] = kexc25519_server; 1609 kex->load_host_public_key=&get_hostkey_public_by_type; 1610 kex->load_host_private_key=&get_hostkey_private_by_type; 1611 kex->host_key_index=&get_hostkey_index; 1612 kex->sign = sshd_hostkey_sign; 1613 } 1614} 1615 1616/* This function requries careful sanity checking */ 1617 1618void 1619mm_get_keystate(struct monitor *pmonitor) 1620{ 1621 debug3("%s: Waiting for new keys", __func__); 1622 1623 if ((child_state = sshbuf_new()) == NULL) 1624 fatal("%s: sshbuf_new failed", __func__); 1625 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1626 child_state); 1627 debug3("%s: GOT new keys", __func__); 1628} 1629 1630 1631/* XXX */ 1632 1633#define FD_CLOSEONEXEC(x) do { \ 1634 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1635 fatal("fcntl(%d, F_SETFD)", x); \ 1636} while (0) 1637 1638static void 1639monitor_openfds(struct monitor *mon, int do_logfds) 1640{ 1641 int pair[2]; 1642 1643 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1644 fatal("%s: socketpair: %s", __func__, strerror(errno)); 1645 FD_CLOSEONEXEC(pair[0]); 1646 FD_CLOSEONEXEC(pair[1]); 1647 mon->m_recvfd = pair[0]; 1648 mon->m_sendfd = pair[1]; 1649 1650 if (do_logfds) { 1651 if (pipe(pair) == -1) 1652 fatal("%s: pipe: %s", __func__, strerror(errno)); 1653 FD_CLOSEONEXEC(pair[0]); 1654 FD_CLOSEONEXEC(pair[1]); 1655 mon->m_log_recvfd = pair[0]; 1656 mon->m_log_sendfd = pair[1]; 1657 } else 1658 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1659} 1660 1661#define MM_MEMSIZE 65536 1662 1663struct monitor * 1664monitor_init(void) 1665{ 1666 struct monitor *mon; 1667 1668 mon = xcalloc(1, sizeof(*mon)); 1669 monitor_openfds(mon, 1); 1670 1671 return mon; 1672} 1673 1674void 1675monitor_reinit(struct monitor *mon) 1676{ 1677 monitor_openfds(mon, 0); 1678} 1679 1680#ifdef GSSAPI 1681int 1682mm_answer_gss_setup_ctx(int sock, Buffer *m) 1683{ 1684 gss_OID_desc goid; 1685 OM_uint32 major; 1686 u_int len; 1687 1688 if (!options.gss_authentication) 1689 fatal("%s: GSSAPI authentication not enabled", __func__); 1690 1691 goid.elements = buffer_get_string(m, &len); 1692 goid.length = len; 1693 1694 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1695 1696 free(goid.elements); 1697 1698 buffer_clear(m); 1699 buffer_put_int(m, major); 1700 1701 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1702 1703 /* Now we have a context, enable the step */ 1704 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1705 1706 return (0); 1707} 1708 1709int 1710mm_answer_gss_accept_ctx(int sock, Buffer *m) 1711{ 1712 gss_buffer_desc in; 1713 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1714 OM_uint32 major, minor; 1715 OM_uint32 flags = 0; /* GSI needs this */ 1716 u_int len; 1717 1718 if (!options.gss_authentication) 1719 fatal("%s: GSSAPI authentication not enabled", __func__); 1720 1721 in.value = buffer_get_string(m, &len); 1722 in.length = len; 1723 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1724 free(in.value); 1725 1726 buffer_clear(m); 1727 buffer_put_int(m, major); 1728 buffer_put_string(m, out.value, out.length); 1729 buffer_put_int(m, flags); 1730 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1731 1732 gss_release_buffer(&minor, &out); 1733 1734 if (major == GSS_S_COMPLETE) { 1735 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1736 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1737 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1738 } 1739 return (0); 1740} 1741 1742int 1743mm_answer_gss_checkmic(int sock, Buffer *m) 1744{ 1745 gss_buffer_desc gssbuf, mic; 1746 OM_uint32 ret; 1747 u_int len; 1748 1749 if (!options.gss_authentication) 1750 fatal("%s: GSSAPI authentication not enabled", __func__); 1751 1752 gssbuf.value = buffer_get_string(m, &len); 1753 gssbuf.length = len; 1754 mic.value = buffer_get_string(m, &len); 1755 mic.length = len; 1756 1757 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1758 1759 free(gssbuf.value); 1760 free(mic.value); 1761 1762 buffer_clear(m); 1763 buffer_put_int(m, ret); 1764 1765 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1766 1767 if (!GSS_ERROR(ret)) 1768 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1769 1770 return (0); 1771} 1772 1773int 1774mm_answer_gss_userok(int sock, Buffer *m) 1775{ 1776 int authenticated; 1777 1778 if (!options.gss_authentication) 1779 fatal("%s: GSSAPI authentication not enabled", __func__); 1780 1781 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1782 1783 buffer_clear(m); 1784 buffer_put_int(m, authenticated); 1785 1786 debug3("%s: sending result %d", __func__, authenticated); 1787 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1788 1789 auth_method = "gssapi-with-mic"; 1790 1791 /* Monitor loop will terminate if authenticated */ 1792 return (authenticated); 1793} 1794#endif /* GSSAPI */ 1795 1796