monitor.c revision 1.150
1/* $OpenBSD: monitor.c,v 1.150 2015/06/22 23:42:16 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 <paths.h> 41#include <poll.h> 42#include <pwd.h> 43#include <signal.h> 44#include <stdarg.h> 45#include <stdint.h> 46#include <stdio.h> 47#include <stdlib.h> 48#include <string.h> 49 50#include "atomicio.h" 51#include "xmalloc.h" 52#include "ssh.h" 53#include "key.h" 54#include "buffer.h" 55#include "hostfile.h" 56#include "auth.h" 57#include "cipher.h" 58#include "kex.h" 59#include "dh.h" 60#include <zlib.h> 61#include "packet.h" 62#include "auth-options.h" 63#include "sshpty.h" 64#include "channels.h" 65#include "session.h" 66#include "sshlogin.h" 67#include "canohost.h" 68#include "log.h" 69#include "misc.h" 70#include "servconf.h" 71#include "monitor.h" 72#include "monitor_mm.h" 73#ifdef GSSAPI 74#include "ssh-gss.h" 75#endif 76#include "monitor_wrap.h" 77#include "monitor_fdpass.h" 78#include "compat.h" 79#include "ssh2.h" 80#include "roaming.h" 81#include "authfd.h" 82#include "match.h" 83#include "ssherr.h" 84 85#ifdef GSSAPI 86static Gssctxt *gsscontext = NULL; 87#endif 88 89/* Imports */ 90extern ServerOptions options; 91extern u_int utmp_len; 92extern u_char session_id[]; 93extern Buffer auth_debug; 94extern int auth_debug_init; 95extern Buffer loginmsg; 96 97/* State exported from the child */ 98static struct sshbuf *child_state; 99 100/* Functions on the monitor that answer unprivileged requests */ 101 102int mm_answer_moduli(int, Buffer *); 103int mm_answer_sign(int, Buffer *); 104int mm_answer_pwnamallow(int, Buffer *); 105int mm_answer_auth2_read_banner(int, Buffer *); 106int mm_answer_authserv(int, Buffer *); 107int mm_answer_authpassword(int, Buffer *); 108int mm_answer_bsdauthquery(int, Buffer *); 109int mm_answer_bsdauthrespond(int, Buffer *); 110int mm_answer_skeyquery(int, Buffer *); 111int mm_answer_skeyrespond(int, Buffer *); 112int mm_answer_keyallowed(int, Buffer *); 113int mm_answer_keyverify(int, Buffer *); 114int mm_answer_pty(int, Buffer *); 115int mm_answer_pty_cleanup(int, Buffer *); 116int mm_answer_term(int, Buffer *); 117int mm_answer_rsa_keyallowed(int, Buffer *); 118int mm_answer_rsa_challenge(int, Buffer *); 119int mm_answer_rsa_response(int, Buffer *); 120int mm_answer_sesskey(int, Buffer *); 121int mm_answer_sessid(int, Buffer *); 122 123#ifdef GSSAPI 124int mm_answer_gss_setup_ctx(int, Buffer *); 125int mm_answer_gss_accept_ctx(int, Buffer *); 126int mm_answer_gss_userok(int, Buffer *); 127int mm_answer_gss_checkmic(int, Buffer *); 128#endif 129 130static int monitor_read_log(struct monitor *); 131 132static Authctxt *authctxt; 133 134#ifdef WITH_SSH1 135static BIGNUM *ssh1_challenge = NULL; /* used for ssh1 rsa auth */ 136#endif 137 138/* local state for key verify */ 139static u_char *key_blob = NULL; 140static u_int key_bloblen = 0; 141static int key_blobtype = MM_NOKEY; 142static char *hostbased_cuser = NULL; 143static char *hostbased_chost = NULL; 144static char *auth_method = "unknown"; 145static char *auth_submethod = NULL; 146static u_int session_id2_len = 0; 147static u_char *session_id2 = NULL; 148static pid_t monitor_child_pid; 149 150struct 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 165struct 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 187struct 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 198struct 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 214struct 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 223struct mon_table *mon_dispatch; 224 225/* Specifies if a certain message is allowed at the moment */ 226 227static void 228monitor_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 240static void 241monitor_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 254void 255monitor_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 338static void 339monitor_set_child_handler(pid_t pid) 340{ 341 monitor_child_pid = pid; 342} 343 344static void 345monitor_child_handler(int sig) 346{ 347 kill(monitor_child_pid, sig); 348} 349 350void 351monitor_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 381void 382monitor_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 */ 391static void * 392mm_zalloc(struct mm_master *mm, u_int ncount, u_int size) 393{ 394 size_t len = (size_t) size * ncount; 395 void *address; 396 397 if (len == 0 || ncount > SIZE_MAX / size) 398 fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size); 399 400 address = mm_malloc(mm, len); 401 402 return (address); 403} 404 405static void 406mm_zfree(struct mm_master *mm, void *address) 407{ 408 mm_free(mm, address); 409} 410 411static int 412monitor_read_log(struct monitor *pmonitor) 413{ 414 Buffer logmsg; 415 u_int len, level; 416 char *msg; 417 418 buffer_init(&logmsg); 419 420 /* Read length */ 421 buffer_append_space(&logmsg, 4); 422 if (atomicio(read, pmonitor->m_log_recvfd, 423 buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) { 424 if (errno == EPIPE) { 425 buffer_free(&logmsg); 426 debug("%s: child log fd closed", __func__); 427 close(pmonitor->m_log_recvfd); 428 pmonitor->m_log_recvfd = -1; 429 return -1; 430 } 431 fatal("%s: log fd read: %s", __func__, strerror(errno)); 432 } 433 len = buffer_get_int(&logmsg); 434 if (len <= 4 || len > 8192) 435 fatal("%s: invalid log message length %u", __func__, len); 436 437 /* Read severity, message */ 438 buffer_clear(&logmsg); 439 buffer_append_space(&logmsg, len); 440 if (atomicio(read, pmonitor->m_log_recvfd, 441 buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) 442 fatal("%s: log fd read: %s", __func__, strerror(errno)); 443 444 /* Log it */ 445 level = buffer_get_int(&logmsg); 446 msg = buffer_get_string(&logmsg, NULL); 447 if (log_level_name(level) == NULL) 448 fatal("%s: invalid log level %u (corrupted message?)", 449 __func__, level); 450 do_log2(level, "%s [preauth]", msg); 451 452 buffer_free(&logmsg); 453 free(msg); 454 455 return 0; 456} 457 458int 459monitor_read(struct monitor *pmonitor, struct mon_table *ent, 460 struct mon_table **pent) 461{ 462 Buffer m; 463 int ret; 464 u_char type; 465 struct pollfd pfd[2]; 466 467 for (;;) { 468 memset(&pfd, 0, sizeof(pfd)); 469 pfd[0].fd = pmonitor->m_sendfd; 470 pfd[0].events = POLLIN; 471 pfd[1].fd = pmonitor->m_log_recvfd; 472 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 473 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 474 if (errno == EINTR || errno == EAGAIN) 475 continue; 476 fatal("%s: poll: %s", __func__, strerror(errno)); 477 } 478 if (pfd[1].revents) { 479 /* 480 * Drain all log messages before processing next 481 * monitor request. 482 */ 483 monitor_read_log(pmonitor); 484 continue; 485 } 486 if (pfd[0].revents) 487 break; /* Continues below */ 488 } 489 490 buffer_init(&m); 491 492 mm_request_receive(pmonitor->m_sendfd, &m); 493 type = buffer_get_char(&m); 494 495 debug3("%s: checking request %d", __func__, type); 496 497 while (ent->f != NULL) { 498 if (ent->type == type) 499 break; 500 ent++; 501 } 502 503 if (ent->f != NULL) { 504 if (!(ent->flags & MON_PERMIT)) 505 fatal("%s: unpermitted request %d", __func__, 506 type); 507 ret = (*ent->f)(pmonitor->m_sendfd, &m); 508 buffer_free(&m); 509 510 /* The child may use this request only once, disable it */ 511 if (ent->flags & MON_ONCE) { 512 debug2("%s: %d used once, disabling now", __func__, 513 type); 514 ent->flags &= ~MON_PERMIT; 515 } 516 517 if (pent != NULL) 518 *pent = ent; 519 520 return ret; 521 } 522 523 fatal("%s: unsupported request: %d", __func__, type); 524 525 /* NOTREACHED */ 526 return (-1); 527} 528 529/* allowed key state */ 530static int 531monitor_allowed_key(u_char *blob, u_int bloblen) 532{ 533 /* make sure key is allowed */ 534 if (key_blob == NULL || key_bloblen != bloblen || 535 timingsafe_bcmp(key_blob, blob, key_bloblen)) 536 return (0); 537 return (1); 538} 539 540static void 541monitor_reset_key_state(void) 542{ 543 /* reset state */ 544 free(key_blob); 545 free(hostbased_cuser); 546 free(hostbased_chost); 547 key_blob = NULL; 548 key_bloblen = 0; 549 key_blobtype = MM_NOKEY; 550 hostbased_cuser = NULL; 551 hostbased_chost = NULL; 552} 553 554#ifdef WITH_OPENSSL 555int 556mm_answer_moduli(int sock, Buffer *m) 557{ 558 DH *dh; 559 int min, want, max; 560 561 min = buffer_get_int(m); 562 want = buffer_get_int(m); 563 max = buffer_get_int(m); 564 565 debug3("%s: got parameters: %d %d %d", 566 __func__, min, want, max); 567 /* We need to check here, too, in case the child got corrupted */ 568 if (max < min || want < min || max < want) 569 fatal("%s: bad parameters: %d %d %d", 570 __func__, min, want, max); 571 572 buffer_clear(m); 573 574 dh = choose_dh(min, want, max); 575 if (dh == NULL) { 576 buffer_put_char(m, 0); 577 return (0); 578 } else { 579 /* Send first bignum */ 580 buffer_put_char(m, 1); 581 buffer_put_bignum2(m, dh->p); 582 buffer_put_bignum2(m, dh->g); 583 584 DH_free(dh); 585 } 586 mm_request_send(sock, MONITOR_ANS_MODULI, m); 587 return (0); 588} 589#endif 590 591int 592mm_answer_sign(int sock, Buffer *m) 593{ 594 struct ssh *ssh = active_state; /* XXX */ 595 extern int auth_sock; /* XXX move to state struct? */ 596 struct sshkey *key; 597 struct sshbuf *sigbuf; 598 u_char *p; 599 u_char *signature; 600 size_t datlen, siglen; 601 int r, keyid, is_proof = 0; 602 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 603 604 debug3("%s", __func__); 605 606 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 607 (r = sshbuf_get_string(m, &p, &datlen)) != 0) 608 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 609 610 /* 611 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 612 * SHA384 (48 bytes) and SHA512 (64 bytes). 613 * 614 * Otherwise, verify the signature request is for a hostkey 615 * proof. 616 * 617 * XXX perform similar check for KEX signature requests too? 618 * it's not trivial, since what is signed is the hash, rather 619 * than the full kex structure... 620 */ 621 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 622 /* 623 * Construct expected hostkey proof and compare it to what 624 * the client sent us. 625 */ 626 if (session_id2_len == 0) /* hostkeys is never first */ 627 fatal("%s: bad data length: %zu", __func__, datlen); 628 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 629 fatal("%s: no hostkey for index %d", __func__, keyid); 630 if ((sigbuf = sshbuf_new()) == NULL) 631 fatal("%s: sshbuf_new", __func__); 632 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 633 (r = sshbuf_put_string(sigbuf, session_id2, 634 session_id2_len) != 0) || 635 (r = sshkey_puts(key, sigbuf)) != 0) 636 fatal("%s: couldn't prepare private key " 637 "proof buffer: %s", __func__, ssh_err(r)); 638 if (datlen != sshbuf_len(sigbuf) || 639 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 640 fatal("%s: bad data length: %zu, hostkey proof len %zu", 641 __func__, datlen, sshbuf_len(sigbuf)); 642 sshbuf_free(sigbuf); 643 is_proof = 1; 644 } 645 646 /* save session id, it will be passed on the first call */ 647 if (session_id2_len == 0) { 648 session_id2_len = datlen; 649 session_id2 = xmalloc(session_id2_len); 650 memcpy(session_id2, p, session_id2_len); 651 } 652 653 if ((key = get_hostkey_by_index(keyid)) != NULL) { 654 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, 655 datafellows)) != 0) 656 fatal("%s: sshkey_sign failed: %s", 657 __func__, ssh_err(r)); 658 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 659 auth_sock > 0) { 660 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 661 p, datlen, datafellows)) != 0) { 662 fatal("%s: ssh_agent_sign failed: %s", 663 __func__, ssh_err(r)); 664 } 665 } else 666 fatal("%s: no hostkey from index %d", __func__, keyid); 667 668 debug3("%s: %s signature %p(%zu)", __func__, 669 is_proof ? "KEX" : "hostkey proof", signature, siglen); 670 671 sshbuf_reset(m); 672 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 673 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 674 675 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 688int 689mm_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 771int 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 784int 785mm_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 802int 803mm_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 833int 834mm_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 863int 864mm_answer_bsdauthrespond(int sock, Buffer *m) 865{ 866 char *response; 867 int authok; 868 869 if (authctxt->as == 0) 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 894int 895mm_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 if (key != NULL) 968 key_free(key); 969 970 /* clear temporarily storage (used by verify) */ 971 monitor_reset_key_state(); 972 973 if (allowed) { 974 /* Save temporarily for comparison in verify */ 975 key_blob = blob; 976 key_bloblen = bloblen; 977 key_blobtype = type; 978 hostbased_cuser = cuser; 979 hostbased_chost = chost; 980 } else { 981 /* Log failed attempt */ 982 auth_log(authctxt, 0, 0, auth_method, NULL); 983 free(blob); 984 free(cuser); 985 free(chost); 986 } 987 988 debug3("%s: key %p is %s", 989 __func__, key, allowed ? "allowed" : "not allowed"); 990 991 buffer_clear(m); 992 buffer_put_int(m, allowed); 993 buffer_put_int(m, forced_command != NULL); 994 995 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 996 997 if (type == MM_RSAHOSTKEY) 998 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed); 999 1000 return (0); 1001} 1002 1003static int 1004monitor_valid_userblob(u_char *data, u_int datalen) 1005{ 1006 Buffer b; 1007 char *p, *userstyle; 1008 u_int len; 1009 int fail = 0; 1010 1011 buffer_init(&b); 1012 buffer_append(&b, data, datalen); 1013 1014 if (datafellows & SSH_OLD_SESSIONID) { 1015 p = buffer_ptr(&b); 1016 len = buffer_len(&b); 1017 if ((session_id2 == NULL) || 1018 (len < session_id2_len) || 1019 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1020 fail++; 1021 buffer_consume(&b, session_id2_len); 1022 } else { 1023 p = buffer_get_string(&b, &len); 1024 if ((session_id2 == NULL) || 1025 (len != session_id2_len) || 1026 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1027 fail++; 1028 free(p); 1029 } 1030 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 1031 fail++; 1032 p = buffer_get_cstring(&b, NULL); 1033 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1034 authctxt->style ? ":" : "", 1035 authctxt->style ? authctxt->style : ""); 1036 if (strcmp(userstyle, p) != 0) { 1037 logit("wrong user name passed to monitor: expected %s != %.100s", 1038 userstyle, p); 1039 fail++; 1040 } 1041 free(userstyle); 1042 free(p); 1043 buffer_skip_string(&b); 1044 if (datafellows & SSH_BUG_PKAUTH) { 1045 if (!buffer_get_char(&b)) 1046 fail++; 1047 } else { 1048 p = buffer_get_cstring(&b, NULL); 1049 if (strcmp("publickey", p) != 0) 1050 fail++; 1051 free(p); 1052 if (!buffer_get_char(&b)) 1053 fail++; 1054 buffer_skip_string(&b); 1055 } 1056 buffer_skip_string(&b); 1057 if (buffer_len(&b) != 0) 1058 fail++; 1059 buffer_free(&b); 1060 return (fail == 0); 1061} 1062 1063static int 1064monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser, 1065 char *chost) 1066{ 1067 Buffer b; 1068 char *p, *userstyle; 1069 u_int len; 1070 int fail = 0; 1071 1072 buffer_init(&b); 1073 buffer_append(&b, data, datalen); 1074 1075 p = buffer_get_string(&b, &len); 1076 if ((session_id2 == NULL) || 1077 (len != session_id2_len) || 1078 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1079 fail++; 1080 free(p); 1081 1082 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 1083 fail++; 1084 p = buffer_get_cstring(&b, NULL); 1085 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1086 authctxt->style ? ":" : "", 1087 authctxt->style ? authctxt->style : ""); 1088 if (strcmp(userstyle, p) != 0) { 1089 logit("wrong user name passed to monitor: expected %s != %.100s", 1090 userstyle, p); 1091 fail++; 1092 } 1093 free(userstyle); 1094 free(p); 1095 buffer_skip_string(&b); /* service */ 1096 p = buffer_get_cstring(&b, NULL); 1097 if (strcmp(p, "hostbased") != 0) 1098 fail++; 1099 free(p); 1100 buffer_skip_string(&b); /* pkalg */ 1101 buffer_skip_string(&b); /* pkblob */ 1102 1103 /* verify client host, strip trailing dot if necessary */ 1104 p = buffer_get_string(&b, NULL); 1105 if (((len = strlen(p)) > 0) && p[len - 1] == '.') 1106 p[len - 1] = '\0'; 1107 if (strcmp(p, chost) != 0) 1108 fail++; 1109 free(p); 1110 1111 /* verify client user */ 1112 p = buffer_get_string(&b, NULL); 1113 if (strcmp(p, cuser) != 0) 1114 fail++; 1115 free(p); 1116 1117 if (buffer_len(&b) != 0) 1118 fail++; 1119 buffer_free(&b); 1120 return (fail == 0); 1121} 1122 1123int 1124mm_answer_keyverify(int sock, Buffer *m) 1125{ 1126 Key *key; 1127 u_char *signature, *data, *blob; 1128 u_int signaturelen, datalen, bloblen; 1129 int verified = 0; 1130 int valid_data = 0; 1131 1132 blob = buffer_get_string(m, &bloblen); 1133 signature = buffer_get_string(m, &signaturelen); 1134 data = buffer_get_string(m, &datalen); 1135 1136 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1137 !monitor_allowed_key(blob, bloblen)) 1138 fatal("%s: bad key, not previously allowed", __func__); 1139 1140 key = key_from_blob(blob, bloblen); 1141 if (key == NULL) 1142 fatal("%s: bad public key blob", __func__); 1143 1144 switch (key_blobtype) { 1145 case MM_USERKEY: 1146 valid_data = monitor_valid_userblob(data, datalen); 1147 break; 1148 case MM_HOSTKEY: 1149 valid_data = monitor_valid_hostbasedblob(data, datalen, 1150 hostbased_cuser, hostbased_chost); 1151 break; 1152 default: 1153 valid_data = 0; 1154 break; 1155 } 1156 if (!valid_data) 1157 fatal("%s: bad signature data blob", __func__); 1158 1159 verified = key_verify(key, signature, signaturelen, data, datalen); 1160 debug3("%s: key %p signature %s", 1161 __func__, key, (verified == 1) ? "verified" : "unverified"); 1162 1163 /* If auth was successful then record key to ensure it isn't reused */ 1164 if (verified == 1) 1165 auth2_record_userkey(authctxt, key); 1166 else 1167 key_free(key); 1168 1169 free(blob); 1170 free(signature); 1171 free(data); 1172 1173 auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased"; 1174 1175 monitor_reset_key_state(); 1176 1177 buffer_clear(m); 1178 buffer_put_int(m, verified); 1179 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1180 1181 return (verified == 1); 1182} 1183 1184static void 1185mm_record_login(Session *s, struct passwd *pw) 1186{ 1187 socklen_t fromlen; 1188 struct sockaddr_storage from; 1189 1190 if (options.use_login) 1191 return; 1192 1193 /* 1194 * Get IP address of client. If the connection is not a socket, let 1195 * the address be 0.0.0.0. 1196 */ 1197 memset(&from, 0, sizeof(from)); 1198 fromlen = sizeof(from); 1199 if (packet_connection_is_on_socket()) { 1200 if (getpeername(packet_get_connection_in(), 1201 (struct sockaddr *)&from, &fromlen) < 0) { 1202 debug("getpeername: %.100s", strerror(errno)); 1203 cleanup_exit(255); 1204 } 1205 } 1206 /* Record that there was a login on that tty from the remote host. */ 1207 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1208 get_remote_name_or_ip(utmp_len, options.use_dns), 1209 (struct sockaddr *)&from, fromlen); 1210} 1211 1212static void 1213mm_session_close(Session *s) 1214{ 1215 debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid); 1216 if (s->ttyfd != -1) { 1217 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd); 1218 session_pty_cleanup2(s); 1219 } 1220 session_unused(s->self); 1221} 1222 1223int 1224mm_answer_pty(int sock, Buffer *m) 1225{ 1226 extern struct monitor *pmonitor; 1227 Session *s; 1228 int res, fd0; 1229 1230 debug3("%s entering", __func__); 1231 1232 buffer_clear(m); 1233 s = session_new(); 1234 if (s == NULL) 1235 goto error; 1236 s->authctxt = authctxt; 1237 s->pw = authctxt->pw; 1238 s->pid = pmonitor->m_pid; 1239 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1240 if (res == 0) 1241 goto error; 1242 pty_setowner(authctxt->pw, s->tty); 1243 1244 buffer_put_int(m, 1); 1245 buffer_put_cstring(m, s->tty); 1246 1247 /* We need to trick ttyslot */ 1248 if (dup2(s->ttyfd, 0) == -1) 1249 fatal("%s: dup2", __func__); 1250 1251 mm_record_login(s, authctxt->pw); 1252 1253 /* Now we can close the file descriptor again */ 1254 close(0); 1255 1256 /* send messages generated by record_login */ 1257 buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg)); 1258 buffer_clear(&loginmsg); 1259 1260 mm_request_send(sock, MONITOR_ANS_PTY, m); 1261 1262 if (mm_send_fd(sock, s->ptyfd) == -1 || 1263 mm_send_fd(sock, s->ttyfd) == -1) 1264 fatal("%s: send fds failed", __func__); 1265 1266 /* make sure nothing uses fd 0 */ 1267 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0) 1268 fatal("%s: open(/dev/null): %s", __func__, strerror(errno)); 1269 if (fd0 != 0) 1270 error("%s: fd0 %d != 0", __func__, fd0); 1271 1272 /* slave is not needed */ 1273 close(s->ttyfd); 1274 s->ttyfd = s->ptyfd; 1275 /* no need to dup() because nobody closes ptyfd */ 1276 s->ptymaster = s->ptyfd; 1277 1278 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd); 1279 1280 return (0); 1281 1282 error: 1283 if (s != NULL) 1284 mm_session_close(s); 1285 buffer_put_int(m, 0); 1286 mm_request_send(sock, MONITOR_ANS_PTY, m); 1287 return (0); 1288} 1289 1290int 1291mm_answer_pty_cleanup(int sock, Buffer *m) 1292{ 1293 Session *s; 1294 char *tty; 1295 1296 debug3("%s entering", __func__); 1297 1298 tty = buffer_get_string(m, NULL); 1299 if ((s = session_by_tty(tty)) != NULL) 1300 mm_session_close(s); 1301 buffer_clear(m); 1302 free(tty); 1303 return (0); 1304} 1305 1306#ifdef WITH_SSH1 1307int 1308mm_answer_sesskey(int sock, Buffer *m) 1309{ 1310 BIGNUM *p; 1311 int rsafail; 1312 1313 /* Turn off permissions */ 1314 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 0); 1315 1316 if ((p = BN_new()) == NULL) 1317 fatal("%s: BN_new", __func__); 1318 1319 buffer_get_bignum2(m, p); 1320 1321 rsafail = ssh1_session_key(p); 1322 1323 buffer_clear(m); 1324 buffer_put_int(m, rsafail); 1325 buffer_put_bignum2(m, p); 1326 1327 BN_clear_free(p); 1328 1329 mm_request_send(sock, MONITOR_ANS_SESSKEY, m); 1330 1331 /* Turn on permissions for sessid passing */ 1332 monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1); 1333 1334 return (0); 1335} 1336 1337int 1338mm_answer_sessid(int sock, Buffer *m) 1339{ 1340 int i; 1341 1342 debug3("%s entering", __func__); 1343 1344 if (buffer_len(m) != 16) 1345 fatal("%s: bad ssh1 session id", __func__); 1346 for (i = 0; i < 16; i++) 1347 session_id[i] = buffer_get_char(m); 1348 1349 /* Turn on permissions for getpwnam */ 1350 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 1351 1352 return (0); 1353} 1354 1355int 1356mm_answer_rsa_keyallowed(int sock, Buffer *m) 1357{ 1358 BIGNUM *client_n; 1359 Key *key = NULL; 1360 u_char *blob = NULL; 1361 u_int blen = 0; 1362 int allowed = 0; 1363 1364 debug3("%s entering", __func__); 1365 1366 auth_method = "rsa"; 1367 if (options.rsa_authentication && authctxt->valid) { 1368 if ((client_n = BN_new()) == NULL) 1369 fatal("%s: BN_new", __func__); 1370 buffer_get_bignum2(m, client_n); 1371 allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key); 1372 BN_clear_free(client_n); 1373 } 1374 buffer_clear(m); 1375 buffer_put_int(m, allowed); 1376 buffer_put_int(m, forced_command != NULL); 1377 1378 /* clear temporarily storage (used by generate challenge) */ 1379 monitor_reset_key_state(); 1380 1381 if (allowed && key != NULL) { 1382 key->type = KEY_RSA; /* cheat for key_to_blob */ 1383 if (key_to_blob(key, &blob, &blen) == 0) 1384 fatal("%s: key_to_blob failed", __func__); 1385 buffer_put_string(m, blob, blen); 1386 1387 /* Save temporarily for comparison in verify */ 1388 key_blob = blob; 1389 key_bloblen = blen; 1390 key_blobtype = MM_RSAUSERKEY; 1391 } 1392 if (key != NULL) 1393 key_free(key); 1394 1395 mm_request_send(sock, MONITOR_ANS_RSAKEYALLOWED, m); 1396 1397 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed); 1398 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0); 1399 return (0); 1400} 1401 1402int 1403mm_answer_rsa_challenge(int sock, Buffer *m) 1404{ 1405 Key *key = NULL; 1406 u_char *blob; 1407 u_int blen; 1408 1409 debug3("%s entering", __func__); 1410 1411 if (!authctxt->valid) 1412 fatal("%s: authctxt not valid", __func__); 1413 blob = buffer_get_string(m, &blen); 1414 if (!monitor_allowed_key(blob, blen)) 1415 fatal("%s: bad key, not previously allowed", __func__); 1416 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) 1417 fatal("%s: key type mismatch", __func__); 1418 if ((key = key_from_blob(blob, blen)) == NULL) 1419 fatal("%s: received bad key", __func__); 1420 if (key->type != KEY_RSA) 1421 fatal("%s: received bad key type %d", __func__, key->type); 1422 key->type = KEY_RSA1; 1423 if (ssh1_challenge) 1424 BN_clear_free(ssh1_challenge); 1425 ssh1_challenge = auth_rsa_generate_challenge(key); 1426 1427 buffer_clear(m); 1428 buffer_put_bignum2(m, ssh1_challenge); 1429 1430 debug3("%s sending reply", __func__); 1431 mm_request_send(sock, MONITOR_ANS_RSACHALLENGE, m); 1432 1433 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1); 1434 1435 free(blob); 1436 key_free(key); 1437 return (0); 1438} 1439 1440int 1441mm_answer_rsa_response(int sock, Buffer *m) 1442{ 1443 Key *key = NULL; 1444 u_char *blob, *response; 1445 u_int blen, len; 1446 int success; 1447 1448 debug3("%s entering", __func__); 1449 1450 if (!authctxt->valid) 1451 fatal("%s: authctxt not valid", __func__); 1452 if (ssh1_challenge == NULL) 1453 fatal("%s: no ssh1_challenge", __func__); 1454 1455 blob = buffer_get_string(m, &blen); 1456 if (!monitor_allowed_key(blob, blen)) 1457 fatal("%s: bad key, not previously allowed", __func__); 1458 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) 1459 fatal("%s: key type mismatch: %d", __func__, key_blobtype); 1460 if ((key = key_from_blob(blob, blen)) == NULL) 1461 fatal("%s: received bad key", __func__); 1462 response = buffer_get_string(m, &len); 1463 if (len != 16) 1464 fatal("%s: received bad response to challenge", __func__); 1465 success = auth_rsa_verify_response(key, ssh1_challenge, response); 1466 1467 free(blob); 1468 key_free(key); 1469 free(response); 1470 1471 auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa"; 1472 1473 /* reset state */ 1474 BN_clear_free(ssh1_challenge); 1475 ssh1_challenge = NULL; 1476 monitor_reset_key_state(); 1477 1478 buffer_clear(m); 1479 buffer_put_int(m, success); 1480 mm_request_send(sock, MONITOR_ANS_RSARESPONSE, m); 1481 1482 return (success); 1483} 1484#endif 1485 1486int 1487mm_answer_term(int sock, Buffer *req) 1488{ 1489 extern struct monitor *pmonitor; 1490 int res, status; 1491 1492 debug3("%s: tearing down sessions", __func__); 1493 1494 /* The child is terminating */ 1495 session_destroy_all(&mm_session_close); 1496 1497 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1498 if (errno != EINTR) 1499 exit(1); 1500 1501 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1502 1503 /* Terminate process */ 1504 exit(res); 1505} 1506 1507void 1508monitor_apply_keystate(struct monitor *pmonitor) 1509{ 1510 struct ssh *ssh = active_state; /* XXX */ 1511 struct kex *kex; 1512 int r; 1513 1514 debug3("%s: packet_set_state", __func__); 1515 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1516 fatal("%s: packet_set_state: %s", __func__, ssh_err(r)); 1517 sshbuf_free(child_state); 1518 child_state = NULL; 1519 1520 if ((kex = ssh->kex) != 0) { 1521 /* XXX set callbacks */ 1522#ifdef WITH_OPENSSL 1523 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; 1524 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; 1525 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1526 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1527 kex->kex[KEX_ECDH_SHA2] = kexecdh_server; 1528#endif 1529 kex->kex[KEX_C25519_SHA256] = kexc25519_server; 1530 kex->load_host_public_key=&get_hostkey_public_by_type; 1531 kex->load_host_private_key=&get_hostkey_private_by_type; 1532 kex->host_key_index=&get_hostkey_index; 1533 kex->sign = sshd_hostkey_sign; 1534 } 1535 1536 /* Update with new address */ 1537 if (options.compression) { 1538 ssh_packet_set_compress_hooks(ssh, pmonitor->m_zlib, 1539 (ssh_packet_comp_alloc_func *)mm_zalloc, 1540 (ssh_packet_comp_free_func *)mm_zfree); 1541 } 1542} 1543 1544/* This function requries careful sanity checking */ 1545 1546void 1547mm_get_keystate(struct monitor *pmonitor) 1548{ 1549 debug3("%s: Waiting for new keys", __func__); 1550 1551 if ((child_state = sshbuf_new()) == NULL) 1552 fatal("%s: sshbuf_new failed", __func__); 1553 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1554 child_state); 1555 debug3("%s: GOT new keys", __func__); 1556} 1557 1558 1559/* XXX */ 1560 1561#define FD_CLOSEONEXEC(x) do { \ 1562 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1563 fatal("fcntl(%d, F_SETFD)", x); \ 1564} while (0) 1565 1566static void 1567monitor_openfds(struct monitor *mon, int do_logfds) 1568{ 1569 int pair[2]; 1570 1571 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1572 fatal("%s: socketpair: %s", __func__, strerror(errno)); 1573 FD_CLOSEONEXEC(pair[0]); 1574 FD_CLOSEONEXEC(pair[1]); 1575 mon->m_recvfd = pair[0]; 1576 mon->m_sendfd = pair[1]; 1577 1578 if (do_logfds) { 1579 if (pipe(pair) == -1) 1580 fatal("%s: pipe: %s", __func__, strerror(errno)); 1581 FD_CLOSEONEXEC(pair[0]); 1582 FD_CLOSEONEXEC(pair[1]); 1583 mon->m_log_recvfd = pair[0]; 1584 mon->m_log_sendfd = pair[1]; 1585 } else 1586 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1587} 1588 1589#define MM_MEMSIZE 65536 1590 1591struct monitor * 1592monitor_init(void) 1593{ 1594 struct ssh *ssh = active_state; /* XXX */ 1595 struct monitor *mon; 1596 1597 mon = xcalloc(1, sizeof(*mon)); 1598 1599 monitor_openfds(mon, 1); 1600 1601 /* Used to share zlib space across processes */ 1602 if (options.compression) { 1603 mon->m_zback = mm_create(NULL, MM_MEMSIZE); 1604 mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE); 1605 1606 /* Compression needs to share state across borders */ 1607 ssh_packet_set_compress_hooks(ssh, mon->m_zlib, 1608 (ssh_packet_comp_alloc_func *)mm_zalloc, 1609 (ssh_packet_comp_free_func *)mm_zfree); 1610 } 1611 1612 return mon; 1613} 1614 1615void 1616monitor_reinit(struct monitor *mon) 1617{ 1618 monitor_openfds(mon, 0); 1619} 1620 1621#ifdef GSSAPI 1622int 1623mm_answer_gss_setup_ctx(int sock, Buffer *m) 1624{ 1625 gss_OID_desc goid; 1626 OM_uint32 major; 1627 u_int len; 1628 1629 goid.elements = buffer_get_string(m, &len); 1630 goid.length = len; 1631 1632 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1633 1634 free(goid.elements); 1635 1636 buffer_clear(m); 1637 buffer_put_int(m, major); 1638 1639 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1640 1641 /* Now we have a context, enable the step */ 1642 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1643 1644 return (0); 1645} 1646 1647int 1648mm_answer_gss_accept_ctx(int sock, Buffer *m) 1649{ 1650 gss_buffer_desc in; 1651 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1652 OM_uint32 major, minor; 1653 OM_uint32 flags = 0; /* GSI needs this */ 1654 u_int len; 1655 1656 in.value = buffer_get_string(m, &len); 1657 in.length = len; 1658 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1659 free(in.value); 1660 1661 buffer_clear(m); 1662 buffer_put_int(m, major); 1663 buffer_put_string(m, out.value, out.length); 1664 buffer_put_int(m, flags); 1665 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1666 1667 gss_release_buffer(&minor, &out); 1668 1669 if (major == GSS_S_COMPLETE) { 1670 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1671 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1672 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1673 } 1674 return (0); 1675} 1676 1677int 1678mm_answer_gss_checkmic(int sock, Buffer *m) 1679{ 1680 gss_buffer_desc gssbuf, mic; 1681 OM_uint32 ret; 1682 u_int len; 1683 1684 gssbuf.value = buffer_get_string(m, &len); 1685 gssbuf.length = len; 1686 mic.value = buffer_get_string(m, &len); 1687 mic.length = len; 1688 1689 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1690 1691 free(gssbuf.value); 1692 free(mic.value); 1693 1694 buffer_clear(m); 1695 buffer_put_int(m, ret); 1696 1697 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1698 1699 if (!GSS_ERROR(ret)) 1700 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1701 1702 return (0); 1703} 1704 1705int 1706mm_answer_gss_userok(int sock, Buffer *m) 1707{ 1708 int authenticated; 1709 1710 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1711 1712 buffer_clear(m); 1713 buffer_put_int(m, authenticated); 1714 1715 debug3("%s: sending result %d", __func__, authenticated); 1716 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1717 1718 auth_method = "gssapi-with-mic"; 1719 1720 /* Monitor loop will terminate if authenticated */ 1721 return (authenticated); 1722} 1723#endif /* GSSAPI */ 1724 1725