monitor.c revision 1.155
1/* $OpenBSD: monitor.c,v 1.155 2015/12/04 16:41:28 markus 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 if (size == 0 || ncount == 0 || ncount > SIZE_MAX / size) 395 fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size); 396 397 return mm_malloc(mm, size * ncount); 398} 399 400static void 401mm_zfree(struct mm_master *mm, void *address) 402{ 403 mm_free(mm, address); 404} 405 406static int 407monitor_read_log(struct monitor *pmonitor) 408{ 409 Buffer logmsg; 410 u_int len, level; 411 char *msg; 412 413 buffer_init(&logmsg); 414 415 /* Read length */ 416 buffer_append_space(&logmsg, 4); 417 if (atomicio(read, pmonitor->m_log_recvfd, 418 buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) { 419 if (errno == EPIPE) { 420 buffer_free(&logmsg); 421 debug("%s: child log fd closed", __func__); 422 close(pmonitor->m_log_recvfd); 423 pmonitor->m_log_recvfd = -1; 424 return -1; 425 } 426 fatal("%s: log fd read: %s", __func__, strerror(errno)); 427 } 428 len = buffer_get_int(&logmsg); 429 if (len <= 4 || len > 8192) 430 fatal("%s: invalid log message length %u", __func__, len); 431 432 /* Read severity, message */ 433 buffer_clear(&logmsg); 434 buffer_append_space(&logmsg, len); 435 if (atomicio(read, pmonitor->m_log_recvfd, 436 buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) 437 fatal("%s: log fd read: %s", __func__, strerror(errno)); 438 439 /* Log it */ 440 level = buffer_get_int(&logmsg); 441 msg = buffer_get_string(&logmsg, NULL); 442 if (log_level_name(level) == NULL) 443 fatal("%s: invalid log level %u (corrupted message?)", 444 __func__, level); 445 do_log2(level, "%s [preauth]", msg); 446 447 buffer_free(&logmsg); 448 free(msg); 449 450 return 0; 451} 452 453int 454monitor_read(struct monitor *pmonitor, struct mon_table *ent, 455 struct mon_table **pent) 456{ 457 Buffer m; 458 int ret; 459 u_char type; 460 struct pollfd pfd[2]; 461 462 for (;;) { 463 memset(&pfd, 0, sizeof(pfd)); 464 pfd[0].fd = pmonitor->m_sendfd; 465 pfd[0].events = POLLIN; 466 pfd[1].fd = pmonitor->m_log_recvfd; 467 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 468 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 469 if (errno == EINTR || errno == EAGAIN) 470 continue; 471 fatal("%s: poll: %s", __func__, strerror(errno)); 472 } 473 if (pfd[1].revents) { 474 /* 475 * Drain all log messages before processing next 476 * monitor request. 477 */ 478 monitor_read_log(pmonitor); 479 continue; 480 } 481 if (pfd[0].revents) 482 break; /* Continues below */ 483 } 484 485 buffer_init(&m); 486 487 mm_request_receive(pmonitor->m_sendfd, &m); 488 type = buffer_get_char(&m); 489 490 debug3("%s: checking request %d", __func__, type); 491 492 while (ent->f != NULL) { 493 if (ent->type == type) 494 break; 495 ent++; 496 } 497 498 if (ent->f != NULL) { 499 if (!(ent->flags & MON_PERMIT)) 500 fatal("%s: unpermitted request %d", __func__, 501 type); 502 ret = (*ent->f)(pmonitor->m_sendfd, &m); 503 buffer_free(&m); 504 505 /* The child may use this request only once, disable it */ 506 if (ent->flags & MON_ONCE) { 507 debug2("%s: %d used once, disabling now", __func__, 508 type); 509 ent->flags &= ~MON_PERMIT; 510 } 511 512 if (pent != NULL) 513 *pent = ent; 514 515 return ret; 516 } 517 518 fatal("%s: unsupported request: %d", __func__, type); 519 520 /* NOTREACHED */ 521 return (-1); 522} 523 524/* allowed key state */ 525static int 526monitor_allowed_key(u_char *blob, u_int bloblen) 527{ 528 /* make sure key is allowed */ 529 if (key_blob == NULL || key_bloblen != bloblen || 530 timingsafe_bcmp(key_blob, blob, key_bloblen)) 531 return (0); 532 return (1); 533} 534 535static void 536monitor_reset_key_state(void) 537{ 538 /* reset state */ 539 free(key_blob); 540 free(hostbased_cuser); 541 free(hostbased_chost); 542 key_blob = NULL; 543 key_bloblen = 0; 544 key_blobtype = MM_NOKEY; 545 hostbased_cuser = NULL; 546 hostbased_chost = NULL; 547} 548 549#ifdef WITH_OPENSSL 550int 551mm_answer_moduli(int sock, Buffer *m) 552{ 553 DH *dh; 554 int min, want, max; 555 556 min = buffer_get_int(m); 557 want = buffer_get_int(m); 558 max = buffer_get_int(m); 559 560 debug3("%s: got parameters: %d %d %d", 561 __func__, min, want, max); 562 /* We need to check here, too, in case the child got corrupted */ 563 if (max < min || want < min || max < want) 564 fatal("%s: bad parameters: %d %d %d", 565 __func__, min, want, max); 566 567 buffer_clear(m); 568 569 dh = choose_dh(min, want, max); 570 if (dh == NULL) { 571 buffer_put_char(m, 0); 572 return (0); 573 } else { 574 /* Send first bignum */ 575 buffer_put_char(m, 1); 576 buffer_put_bignum2(m, dh->p); 577 buffer_put_bignum2(m, dh->g); 578 579 DH_free(dh); 580 } 581 mm_request_send(sock, MONITOR_ANS_MODULI, m); 582 return (0); 583} 584#endif 585 586int 587mm_answer_sign(int sock, Buffer *m) 588{ 589 struct ssh *ssh = active_state; /* XXX */ 590 extern int auth_sock; /* XXX move to state struct? */ 591 struct sshkey *key; 592 struct sshbuf *sigbuf; 593 u_char *p; 594 u_char *signature; 595 char *alg; 596 size_t datlen, siglen, alglen; 597 int r, keyid, is_proof = 0; 598 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 599 600 debug3("%s", __func__); 601 602 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 603 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 604 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0) 605 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 606 607 /* 608 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 609 * SHA384 (48 bytes) and SHA512 (64 bytes). 610 * 611 * Otherwise, verify the signature request is for a hostkey 612 * proof. 613 * 614 * XXX perform similar check for KEX signature requests too? 615 * it's not trivial, since what is signed is the hash, rather 616 * than the full kex structure... 617 */ 618 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 619 /* 620 * Construct expected hostkey proof and compare it to what 621 * the client sent us. 622 */ 623 if (session_id2_len == 0) /* hostkeys is never first */ 624 fatal("%s: bad data length: %zu", __func__, datlen); 625 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 626 fatal("%s: no hostkey for index %d", __func__, keyid); 627 if ((sigbuf = sshbuf_new()) == NULL) 628 fatal("%s: sshbuf_new", __func__); 629 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 630 (r = sshbuf_put_string(sigbuf, session_id2, 631 session_id2_len)) != 0 || 632 (r = sshkey_puts(key, sigbuf)) != 0) 633 fatal("%s: couldn't prepare private key " 634 "proof buffer: %s", __func__, ssh_err(r)); 635 if (datlen != sshbuf_len(sigbuf) || 636 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 637 fatal("%s: bad data length: %zu, hostkey proof len %zu", 638 __func__, datlen, sshbuf_len(sigbuf)); 639 sshbuf_free(sigbuf); 640 is_proof = 1; 641 } 642 643 /* save session id, it will be passed on the first call */ 644 if (session_id2_len == 0) { 645 session_id2_len = datlen; 646 session_id2 = xmalloc(session_id2_len); 647 memcpy(session_id2, p, session_id2_len); 648 } 649 650 if ((key = get_hostkey_by_index(keyid)) != NULL) { 651 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 652 datafellows)) != 0) 653 fatal("%s: sshkey_sign failed: %s", 654 __func__, ssh_err(r)); 655 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 656 auth_sock > 0) { 657 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 658 p, datlen, alg, datafellows)) != 0) { 659 fatal("%s: ssh_agent_sign failed: %s", 660 __func__, ssh_err(r)); 661 } 662 } else 663 fatal("%s: no hostkey from index %d", __func__, keyid); 664 665 debug3("%s: %s signature %p(%zu)", __func__, 666 is_proof ? "KEX" : "hostkey proof", signature, siglen); 667 668 sshbuf_reset(m); 669 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 670 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 671 672 free(p); 673 free(signature); 674 675 mm_request_send(sock, MONITOR_ANS_SIGN, m); 676 677 /* Turn on permissions for getpwnam */ 678 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 679 680 return (0); 681} 682 683/* Retrieves the password entry and also checks if the user is permitted */ 684 685int 686mm_answer_pwnamallow(int sock, Buffer *m) 687{ 688 char *username; 689 struct passwd *pwent; 690 int allowed = 0; 691 u_int i; 692 693 debug3("%s", __func__); 694 695 if (authctxt->attempt++ != 0) 696 fatal("%s: multiple attempts for getpwnam", __func__); 697 698 username = buffer_get_string(m, NULL); 699 700 pwent = getpwnamallow(username); 701 702 authctxt->user = xstrdup(username); 703 setproctitle("%s [priv]", pwent ? username : "unknown"); 704 free(username); 705 706 buffer_clear(m); 707 708 if (pwent == NULL) { 709 buffer_put_char(m, 0); 710 authctxt->pw = fakepw(); 711 goto out; 712 } 713 714 allowed = 1; 715 authctxt->pw = pwent; 716 authctxt->valid = 1; 717 718 buffer_put_char(m, 1); 719 buffer_put_string(m, pwent, sizeof(struct passwd)); 720 buffer_put_cstring(m, pwent->pw_name); 721 buffer_put_cstring(m, "*"); 722 buffer_put_cstring(m, pwent->pw_gecos); 723 buffer_put_cstring(m, pwent->pw_class); 724 buffer_put_cstring(m, pwent->pw_dir); 725 buffer_put_cstring(m, pwent->pw_shell); 726 727 out: 728 buffer_put_string(m, &options, sizeof(options)); 729 730#define M_CP_STROPT(x) do { \ 731 if (options.x != NULL) \ 732 buffer_put_cstring(m, options.x); \ 733 } while (0) 734#define M_CP_STRARRAYOPT(x, nx) do { \ 735 for (i = 0; i < options.nx; i++) \ 736 buffer_put_cstring(m, options.x[i]); \ 737 } while (0) 738 /* See comment in servconf.h */ 739 COPY_MATCH_STRING_OPTS(); 740#undef M_CP_STROPT 741#undef M_CP_STRARRAYOPT 742 743 /* Create valid auth method lists */ 744 if (compat20 && auth2_setup_methods_lists(authctxt) != 0) { 745 /* 746 * The monitor will continue long enough to let the child 747 * run to it's packet_disconnect(), but it must not allow any 748 * authentication to succeed. 749 */ 750 debug("%s: no valid authentication method lists", __func__); 751 } 752 753 debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed); 754 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 755 756 /* For SSHv1 allow authentication now */ 757 if (!compat20) 758 monitor_permit_authentications(1); 759 else { 760 /* Allow service/style information on the auth context */ 761 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 762 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 763 } 764 765 return (0); 766} 767 768int mm_answer_auth2_read_banner(int sock, Buffer *m) 769{ 770 char *banner; 771 772 buffer_clear(m); 773 banner = auth2_read_banner(); 774 buffer_put_cstring(m, banner != NULL ? banner : ""); 775 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 776 free(banner); 777 778 return (0); 779} 780 781int 782mm_answer_authserv(int sock, Buffer *m) 783{ 784 monitor_permit_authentications(1); 785 786 authctxt->service = buffer_get_string(m, NULL); 787 authctxt->style = buffer_get_string(m, NULL); 788 debug3("%s: service=%s, style=%s", 789 __func__, authctxt->service, authctxt->style); 790 791 if (strlen(authctxt->style) == 0) { 792 free(authctxt->style); 793 authctxt->style = NULL; 794 } 795 796 return (0); 797} 798 799int 800mm_answer_authpassword(int sock, Buffer *m) 801{ 802 static int call_count; 803 char *passwd; 804 int authenticated; 805 u_int plen; 806 807 passwd = buffer_get_string(m, &plen); 808 /* Only authenticate if the context is valid */ 809 authenticated = options.password_authentication && 810 auth_password(authctxt, passwd); 811 explicit_bzero(passwd, strlen(passwd)); 812 free(passwd); 813 814 buffer_clear(m); 815 buffer_put_int(m, authenticated); 816 817 debug3("%s: sending result %d", __func__, authenticated); 818 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 819 820 call_count++; 821 if (plen == 0 && call_count == 1) 822 auth_method = "none"; 823 else 824 auth_method = "password"; 825 826 /* Causes monitor loop to terminate if authenticated */ 827 return (authenticated); 828} 829 830int 831mm_answer_bsdauthquery(int sock, Buffer *m) 832{ 833 char *name, *infotxt; 834 u_int numprompts; 835 u_int *echo_on; 836 char **prompts; 837 u_int success; 838 839 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 840 &prompts, &echo_on) < 0 ? 0 : 1; 841 842 buffer_clear(m); 843 buffer_put_int(m, success); 844 if (success) 845 buffer_put_cstring(m, prompts[0]); 846 847 debug3("%s: sending challenge success: %u", __func__, success); 848 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 849 850 if (success) { 851 free(name); 852 free(infotxt); 853 free(prompts); 854 free(echo_on); 855 } 856 857 return (0); 858} 859 860int 861mm_answer_bsdauthrespond(int sock, Buffer *m) 862{ 863 char *response; 864 int authok; 865 866 if (authctxt->as == NULL) 867 fatal("%s: no bsd auth session", __func__); 868 869 response = buffer_get_string(m, NULL); 870 authok = options.challenge_response_authentication && 871 auth_userresponse(authctxt->as, response, 0); 872 authctxt->as = NULL; 873 debug3("%s: <%s> = <%d>", __func__, response, authok); 874 free(response); 875 876 buffer_clear(m); 877 buffer_put_int(m, authok); 878 879 debug3("%s: sending authenticated: %d", __func__, authok); 880 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 881 882 if (compat20) { 883 auth_method = "keyboard-interactive"; 884 auth_submethod = "bsdauth"; 885 } else 886 auth_method = "bsdauth"; 887 888 return (authok != 0); 889} 890 891int 892mm_answer_keyallowed(int sock, Buffer *m) 893{ 894 Key *key; 895 char *cuser, *chost; 896 u_char *blob; 897 u_int bloblen, pubkey_auth_attempt; 898 enum mm_keytype type = 0; 899 int allowed = 0; 900 901 debug3("%s entering", __func__); 902 903 type = buffer_get_int(m); 904 cuser = buffer_get_string(m, NULL); 905 chost = buffer_get_string(m, NULL); 906 blob = buffer_get_string(m, &bloblen); 907 pubkey_auth_attempt = buffer_get_int(m); 908 909 key = key_from_blob(blob, bloblen); 910 911 if ((compat20 && type == MM_RSAHOSTKEY) || 912 (!compat20 && type != MM_RSAHOSTKEY)) 913 fatal("%s: key type and protocol mismatch", __func__); 914 915 debug3("%s: key_from_blob: %p", __func__, key); 916 917 if (key != NULL && authctxt->valid) { 918 /* These should not make it past the privsep child */ 919 if (key_type_plain(key->type) == KEY_RSA && 920 (datafellows & SSH_BUG_RSASIGMD5) != 0) 921 fatal("%s: passed a SSH_BUG_RSASIGMD5 key", __func__); 922 923 switch (type) { 924 case MM_USERKEY: 925 allowed = options.pubkey_authentication && 926 !auth2_userkey_already_used(authctxt, key) && 927 match_pattern_list(sshkey_ssh_name(key), 928 options.pubkey_key_types, 0) == 1 && 929 user_key_allowed(authctxt->pw, key, 930 pubkey_auth_attempt); 931 pubkey_auth_info(authctxt, key, NULL); 932 auth_method = "publickey"; 933 if (options.pubkey_authentication && 934 (!pubkey_auth_attempt || allowed != 1)) 935 auth_clear_options(); 936 break; 937 case MM_HOSTKEY: 938 allowed = options.hostbased_authentication && 939 match_pattern_list(sshkey_ssh_name(key), 940 options.hostbased_key_types, 0) == 1 && 941 hostbased_key_allowed(authctxt->pw, 942 cuser, chost, key); 943 pubkey_auth_info(authctxt, key, 944 "client user \"%.100s\", client host \"%.100s\"", 945 cuser, chost); 946 auth_method = "hostbased"; 947 break; 948#ifdef WITH_SSH1 949 case MM_RSAHOSTKEY: 950 key->type = KEY_RSA1; /* XXX */ 951 allowed = options.rhosts_rsa_authentication && 952 auth_rhosts_rsa_key_allowed(authctxt->pw, 953 cuser, chost, key); 954 if (options.rhosts_rsa_authentication && allowed != 1) 955 auth_clear_options(); 956 auth_method = "rsa"; 957 break; 958#endif 959 default: 960 fatal("%s: unknown key type %d", __func__, type); 961 break; 962 } 963 } 964 if (key != NULL) 965 key_free(key); 966 967 /* clear temporarily storage (used by verify) */ 968 monitor_reset_key_state(); 969 970 if (allowed) { 971 /* Save temporarily for comparison in verify */ 972 key_blob = blob; 973 key_bloblen = bloblen; 974 key_blobtype = type; 975 hostbased_cuser = cuser; 976 hostbased_chost = chost; 977 } else { 978 /* Log failed attempt */ 979 auth_log(authctxt, 0, 0, auth_method, NULL); 980 free(blob); 981 free(cuser); 982 free(chost); 983 } 984 985 debug3("%s: key %p is %s", 986 __func__, key, allowed ? "allowed" : "not allowed"); 987 988 buffer_clear(m); 989 buffer_put_int(m, allowed); 990 buffer_put_int(m, forced_command != NULL); 991 992 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 993 994 if (type == MM_RSAHOSTKEY) 995 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed); 996 997 return (0); 998} 999 1000static int 1001monitor_valid_userblob(u_char *data, u_int datalen) 1002{ 1003 Buffer b; 1004 char *p, *userstyle; 1005 u_int len; 1006 int fail = 0; 1007 1008 buffer_init(&b); 1009 buffer_append(&b, data, datalen); 1010 1011 if (datafellows & SSH_OLD_SESSIONID) { 1012 p = buffer_ptr(&b); 1013 len = buffer_len(&b); 1014 if ((session_id2 == NULL) || 1015 (len < session_id2_len) || 1016 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1017 fail++; 1018 buffer_consume(&b, session_id2_len); 1019 } else { 1020 p = buffer_get_string(&b, &len); 1021 if ((session_id2 == NULL) || 1022 (len != session_id2_len) || 1023 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1024 fail++; 1025 free(p); 1026 } 1027 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 1028 fail++; 1029 p = buffer_get_cstring(&b, NULL); 1030 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1031 authctxt->style ? ":" : "", 1032 authctxt->style ? authctxt->style : ""); 1033 if (strcmp(userstyle, p) != 0) { 1034 logit("wrong user name passed to monitor: expected %s != %.100s", 1035 userstyle, p); 1036 fail++; 1037 } 1038 free(userstyle); 1039 free(p); 1040 buffer_skip_string(&b); 1041 if (datafellows & SSH_BUG_PKAUTH) { 1042 if (!buffer_get_char(&b)) 1043 fail++; 1044 } else { 1045 p = buffer_get_cstring(&b, NULL); 1046 if (strcmp("publickey", p) != 0) 1047 fail++; 1048 free(p); 1049 if (!buffer_get_char(&b)) 1050 fail++; 1051 buffer_skip_string(&b); 1052 } 1053 buffer_skip_string(&b); 1054 if (buffer_len(&b) != 0) 1055 fail++; 1056 buffer_free(&b); 1057 return (fail == 0); 1058} 1059 1060static int 1061monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser, 1062 char *chost) 1063{ 1064 Buffer b; 1065 char *p, *userstyle; 1066 u_int len; 1067 int fail = 0; 1068 1069 buffer_init(&b); 1070 buffer_append(&b, data, datalen); 1071 1072 p = buffer_get_string(&b, &len); 1073 if ((session_id2 == NULL) || 1074 (len != session_id2_len) || 1075 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1076 fail++; 1077 free(p); 1078 1079 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST) 1080 fail++; 1081 p = buffer_get_cstring(&b, NULL); 1082 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1083 authctxt->style ? ":" : "", 1084 authctxt->style ? authctxt->style : ""); 1085 if (strcmp(userstyle, p) != 0) { 1086 logit("wrong user name passed to monitor: expected %s != %.100s", 1087 userstyle, p); 1088 fail++; 1089 } 1090 free(userstyle); 1091 free(p); 1092 buffer_skip_string(&b); /* service */ 1093 p = buffer_get_cstring(&b, NULL); 1094 if (strcmp(p, "hostbased") != 0) 1095 fail++; 1096 free(p); 1097 buffer_skip_string(&b); /* pkalg */ 1098 buffer_skip_string(&b); /* pkblob */ 1099 1100 /* verify client host, strip trailing dot if necessary */ 1101 p = buffer_get_string(&b, NULL); 1102 if (((len = strlen(p)) > 0) && p[len - 1] == '.') 1103 p[len - 1] = '\0'; 1104 if (strcmp(p, chost) != 0) 1105 fail++; 1106 free(p); 1107 1108 /* verify client user */ 1109 p = buffer_get_string(&b, NULL); 1110 if (strcmp(p, cuser) != 0) 1111 fail++; 1112 free(p); 1113 1114 if (buffer_len(&b) != 0) 1115 fail++; 1116 buffer_free(&b); 1117 return (fail == 0); 1118} 1119 1120int 1121mm_answer_keyverify(int sock, Buffer *m) 1122{ 1123 Key *key; 1124 u_char *signature, *data, *blob; 1125 u_int signaturelen, datalen, bloblen; 1126 int verified = 0; 1127 int valid_data = 0; 1128 1129 blob = buffer_get_string(m, &bloblen); 1130 signature = buffer_get_string(m, &signaturelen); 1131 data = buffer_get_string(m, &datalen); 1132 1133 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1134 !monitor_allowed_key(blob, bloblen)) 1135 fatal("%s: bad key, not previously allowed", __func__); 1136 1137 key = key_from_blob(blob, bloblen); 1138 if (key == NULL) 1139 fatal("%s: bad public key blob", __func__); 1140 1141 switch (key_blobtype) { 1142 case MM_USERKEY: 1143 valid_data = monitor_valid_userblob(data, datalen); 1144 break; 1145 case MM_HOSTKEY: 1146 valid_data = monitor_valid_hostbasedblob(data, datalen, 1147 hostbased_cuser, hostbased_chost); 1148 break; 1149 default: 1150 valid_data = 0; 1151 break; 1152 } 1153 if (!valid_data) 1154 fatal("%s: bad signature data blob", __func__); 1155 1156 verified = key_verify(key, signature, signaturelen, data, datalen); 1157 debug3("%s: key %p signature %s", 1158 __func__, key, (verified == 1) ? "verified" : "unverified"); 1159 1160 /* If auth was successful then record key to ensure it isn't reused */ 1161 if (verified == 1 && key_blobtype == MM_USERKEY) 1162 auth2_record_userkey(authctxt, key); 1163 else 1164 key_free(key); 1165 1166 free(blob); 1167 free(signature); 1168 free(data); 1169 1170 auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased"; 1171 1172 monitor_reset_key_state(); 1173 1174 buffer_clear(m); 1175 buffer_put_int(m, verified); 1176 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1177 1178 return (verified == 1); 1179} 1180 1181static void 1182mm_record_login(Session *s, struct passwd *pw) 1183{ 1184 socklen_t fromlen; 1185 struct sockaddr_storage from; 1186 1187 if (options.use_login) 1188 return; 1189 1190 /* 1191 * Get IP address of client. If the connection is not a socket, let 1192 * the address be 0.0.0.0. 1193 */ 1194 memset(&from, 0, sizeof(from)); 1195 fromlen = sizeof(from); 1196 if (packet_connection_is_on_socket()) { 1197 if (getpeername(packet_get_connection_in(), 1198 (struct sockaddr *)&from, &fromlen) < 0) { 1199 debug("getpeername: %.100s", strerror(errno)); 1200 cleanup_exit(255); 1201 } 1202 } 1203 /* Record that there was a login on that tty from the remote host. */ 1204 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1205 get_remote_name_or_ip(utmp_len, options.use_dns), 1206 (struct sockaddr *)&from, fromlen); 1207} 1208 1209static void 1210mm_session_close(Session *s) 1211{ 1212 debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid); 1213 if (s->ttyfd != -1) { 1214 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd); 1215 session_pty_cleanup2(s); 1216 } 1217 session_unused(s->self); 1218} 1219 1220int 1221mm_answer_pty(int sock, Buffer *m) 1222{ 1223 extern struct monitor *pmonitor; 1224 Session *s; 1225 int res, fd0; 1226 1227 debug3("%s entering", __func__); 1228 1229 buffer_clear(m); 1230 s = session_new(); 1231 if (s == NULL) 1232 goto error; 1233 s->authctxt = authctxt; 1234 s->pw = authctxt->pw; 1235 s->pid = pmonitor->m_pid; 1236 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1237 if (res == 0) 1238 goto error; 1239 pty_setowner(authctxt->pw, s->tty); 1240 1241 buffer_put_int(m, 1); 1242 buffer_put_cstring(m, s->tty); 1243 1244 /* We need to trick ttyslot */ 1245 if (dup2(s->ttyfd, 0) == -1) 1246 fatal("%s: dup2", __func__); 1247 1248 mm_record_login(s, authctxt->pw); 1249 1250 /* Now we can close the file descriptor again */ 1251 close(0); 1252 1253 /* send messages generated by record_login */ 1254 buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg)); 1255 buffer_clear(&loginmsg); 1256 1257 mm_request_send(sock, MONITOR_ANS_PTY, m); 1258 1259 if (mm_send_fd(sock, s->ptyfd) == -1 || 1260 mm_send_fd(sock, s->ttyfd) == -1) 1261 fatal("%s: send fds failed", __func__); 1262 1263 /* make sure nothing uses fd 0 */ 1264 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0) 1265 fatal("%s: open(/dev/null): %s", __func__, strerror(errno)); 1266 if (fd0 != 0) 1267 error("%s: fd0 %d != 0", __func__, fd0); 1268 1269 /* slave is not needed */ 1270 close(s->ttyfd); 1271 s->ttyfd = s->ptyfd; 1272 /* no need to dup() because nobody closes ptyfd */ 1273 s->ptymaster = s->ptyfd; 1274 1275 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd); 1276 1277 return (0); 1278 1279 error: 1280 if (s != NULL) 1281 mm_session_close(s); 1282 buffer_put_int(m, 0); 1283 mm_request_send(sock, MONITOR_ANS_PTY, m); 1284 return (0); 1285} 1286 1287int 1288mm_answer_pty_cleanup(int sock, Buffer *m) 1289{ 1290 Session *s; 1291 char *tty; 1292 1293 debug3("%s entering", __func__); 1294 1295 tty = buffer_get_string(m, NULL); 1296 if ((s = session_by_tty(tty)) != NULL) 1297 mm_session_close(s); 1298 buffer_clear(m); 1299 free(tty); 1300 return (0); 1301} 1302 1303#ifdef WITH_SSH1 1304int 1305mm_answer_sesskey(int sock, Buffer *m) 1306{ 1307 BIGNUM *p; 1308 int rsafail; 1309 1310 /* Turn off permissions */ 1311 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 0); 1312 1313 if ((p = BN_new()) == NULL) 1314 fatal("%s: BN_new", __func__); 1315 1316 buffer_get_bignum2(m, p); 1317 1318 rsafail = ssh1_session_key(p); 1319 1320 buffer_clear(m); 1321 buffer_put_int(m, rsafail); 1322 buffer_put_bignum2(m, p); 1323 1324 BN_clear_free(p); 1325 1326 mm_request_send(sock, MONITOR_ANS_SESSKEY, m); 1327 1328 /* Turn on permissions for sessid passing */ 1329 monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1); 1330 1331 return (0); 1332} 1333 1334int 1335mm_answer_sessid(int sock, Buffer *m) 1336{ 1337 int i; 1338 1339 debug3("%s entering", __func__); 1340 1341 if (buffer_len(m) != 16) 1342 fatal("%s: bad ssh1 session id", __func__); 1343 for (i = 0; i < 16; i++) 1344 session_id[i] = buffer_get_char(m); 1345 1346 /* Turn on permissions for getpwnam */ 1347 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 1348 1349 return (0); 1350} 1351 1352int 1353mm_answer_rsa_keyallowed(int sock, Buffer *m) 1354{ 1355 BIGNUM *client_n; 1356 Key *key = NULL; 1357 u_char *blob = NULL; 1358 u_int blen = 0; 1359 int allowed = 0; 1360 1361 debug3("%s entering", __func__); 1362 1363 auth_method = "rsa"; 1364 if (options.rsa_authentication && authctxt->valid) { 1365 if ((client_n = BN_new()) == NULL) 1366 fatal("%s: BN_new", __func__); 1367 buffer_get_bignum2(m, client_n); 1368 allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key); 1369 BN_clear_free(client_n); 1370 } 1371 buffer_clear(m); 1372 buffer_put_int(m, allowed); 1373 buffer_put_int(m, forced_command != NULL); 1374 1375 /* clear temporarily storage (used by generate challenge) */ 1376 monitor_reset_key_state(); 1377 1378 if (allowed && key != NULL) { 1379 key->type = KEY_RSA; /* cheat for key_to_blob */ 1380 if (key_to_blob(key, &blob, &blen) == 0) 1381 fatal("%s: key_to_blob failed", __func__); 1382 buffer_put_string(m, blob, blen); 1383 1384 /* Save temporarily for comparison in verify */ 1385 key_blob = blob; 1386 key_bloblen = blen; 1387 key_blobtype = MM_RSAUSERKEY; 1388 } 1389 if (key != NULL) 1390 key_free(key); 1391 1392 mm_request_send(sock, MONITOR_ANS_RSAKEYALLOWED, m); 1393 1394 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed); 1395 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0); 1396 return (0); 1397} 1398 1399int 1400mm_answer_rsa_challenge(int sock, Buffer *m) 1401{ 1402 Key *key = NULL; 1403 u_char *blob; 1404 u_int blen; 1405 1406 debug3("%s entering", __func__); 1407 1408 if (!authctxt->valid) 1409 fatal("%s: authctxt not valid", __func__); 1410 blob = buffer_get_string(m, &blen); 1411 if (!monitor_allowed_key(blob, blen)) 1412 fatal("%s: bad key, not previously allowed", __func__); 1413 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) 1414 fatal("%s: key type mismatch", __func__); 1415 if ((key = key_from_blob(blob, blen)) == NULL) 1416 fatal("%s: received bad key", __func__); 1417 if (key->type != KEY_RSA) 1418 fatal("%s: received bad key type %d", __func__, key->type); 1419 key->type = KEY_RSA1; 1420 if (ssh1_challenge) 1421 BN_clear_free(ssh1_challenge); 1422 ssh1_challenge = auth_rsa_generate_challenge(key); 1423 1424 buffer_clear(m); 1425 buffer_put_bignum2(m, ssh1_challenge); 1426 1427 debug3("%s sending reply", __func__); 1428 mm_request_send(sock, MONITOR_ANS_RSACHALLENGE, m); 1429 1430 monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1); 1431 1432 free(blob); 1433 key_free(key); 1434 return (0); 1435} 1436 1437int 1438mm_answer_rsa_response(int sock, Buffer *m) 1439{ 1440 Key *key = NULL; 1441 u_char *blob, *response; 1442 u_int blen, len; 1443 int success; 1444 1445 debug3("%s entering", __func__); 1446 1447 if (!authctxt->valid) 1448 fatal("%s: authctxt not valid", __func__); 1449 if (ssh1_challenge == NULL) 1450 fatal("%s: no ssh1_challenge", __func__); 1451 1452 blob = buffer_get_string(m, &blen); 1453 if (!monitor_allowed_key(blob, blen)) 1454 fatal("%s: bad key, not previously allowed", __func__); 1455 if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY) 1456 fatal("%s: key type mismatch: %d", __func__, key_blobtype); 1457 if ((key = key_from_blob(blob, blen)) == NULL) 1458 fatal("%s: received bad key", __func__); 1459 response = buffer_get_string(m, &len); 1460 if (len != 16) 1461 fatal("%s: received bad response to challenge", __func__); 1462 success = auth_rsa_verify_response(key, ssh1_challenge, response); 1463 1464 free(blob); 1465 key_free(key); 1466 free(response); 1467 1468 auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa"; 1469 1470 /* reset state */ 1471 BN_clear_free(ssh1_challenge); 1472 ssh1_challenge = NULL; 1473 monitor_reset_key_state(); 1474 1475 buffer_clear(m); 1476 buffer_put_int(m, success); 1477 mm_request_send(sock, MONITOR_ANS_RSARESPONSE, m); 1478 1479 return (success); 1480} 1481#endif 1482 1483int 1484mm_answer_term(int sock, Buffer *req) 1485{ 1486 extern struct monitor *pmonitor; 1487 int res, status; 1488 1489 debug3("%s: tearing down sessions", __func__); 1490 1491 /* The child is terminating */ 1492 session_destroy_all(&mm_session_close); 1493 1494 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1495 if (errno != EINTR) 1496 exit(1); 1497 1498 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1499 1500 /* Terminate process */ 1501 exit(res); 1502} 1503 1504void 1505monitor_apply_keystate(struct monitor *pmonitor) 1506{ 1507 struct ssh *ssh = active_state; /* XXX */ 1508 struct kex *kex; 1509 int r; 1510 1511 debug3("%s: packet_set_state", __func__); 1512 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1513 fatal("%s: packet_set_state: %s", __func__, ssh_err(r)); 1514 sshbuf_free(child_state); 1515 child_state = NULL; 1516 1517 if ((kex = ssh->kex) != NULL) { 1518 /* XXX set callbacks */ 1519#ifdef WITH_OPENSSL 1520 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; 1521 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; 1522 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1523 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1524 kex->kex[KEX_ECDH_SHA2] = kexecdh_server; 1525#endif 1526 kex->kex[KEX_C25519_SHA256] = kexc25519_server; 1527 kex->load_host_public_key=&get_hostkey_public_by_type; 1528 kex->load_host_private_key=&get_hostkey_private_by_type; 1529 kex->host_key_index=&get_hostkey_index; 1530 kex->sign = sshd_hostkey_sign; 1531 } 1532 1533 /* Update with new address */ 1534 if (options.compression) { 1535 ssh_packet_set_compress_hooks(ssh, pmonitor->m_zlib, 1536 (ssh_packet_comp_alloc_func *)mm_zalloc, 1537 (ssh_packet_comp_free_func *)mm_zfree); 1538 } 1539} 1540 1541/* This function requries careful sanity checking */ 1542 1543void 1544mm_get_keystate(struct monitor *pmonitor) 1545{ 1546 debug3("%s: Waiting for new keys", __func__); 1547 1548 if ((child_state = sshbuf_new()) == NULL) 1549 fatal("%s: sshbuf_new failed", __func__); 1550 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1551 child_state); 1552 debug3("%s: GOT new keys", __func__); 1553} 1554 1555 1556/* XXX */ 1557 1558#define FD_CLOSEONEXEC(x) do { \ 1559 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1560 fatal("fcntl(%d, F_SETFD)", x); \ 1561} while (0) 1562 1563static void 1564monitor_openfds(struct monitor *mon, int do_logfds) 1565{ 1566 int pair[2]; 1567 1568 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1569 fatal("%s: socketpair: %s", __func__, strerror(errno)); 1570 FD_CLOSEONEXEC(pair[0]); 1571 FD_CLOSEONEXEC(pair[1]); 1572 mon->m_recvfd = pair[0]; 1573 mon->m_sendfd = pair[1]; 1574 1575 if (do_logfds) { 1576 if (pipe(pair) == -1) 1577 fatal("%s: pipe: %s", __func__, strerror(errno)); 1578 FD_CLOSEONEXEC(pair[0]); 1579 FD_CLOSEONEXEC(pair[1]); 1580 mon->m_log_recvfd = pair[0]; 1581 mon->m_log_sendfd = pair[1]; 1582 } else 1583 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1584} 1585 1586#define MM_MEMSIZE 65536 1587 1588struct monitor * 1589monitor_init(void) 1590{ 1591 struct ssh *ssh = active_state; /* XXX */ 1592 struct monitor *mon; 1593 1594 mon = xcalloc(1, sizeof(*mon)); 1595 1596 monitor_openfds(mon, 1); 1597 1598 /* Used to share zlib space across processes */ 1599 if (options.compression) { 1600 mon->m_zback = mm_create(NULL, MM_MEMSIZE); 1601 mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE); 1602 1603 /* Compression needs to share state across borders */ 1604 ssh_packet_set_compress_hooks(ssh, mon->m_zlib, 1605 (ssh_packet_comp_alloc_func *)mm_zalloc, 1606 (ssh_packet_comp_free_func *)mm_zfree); 1607 } 1608 1609 return mon; 1610} 1611 1612void 1613monitor_reinit(struct monitor *mon) 1614{ 1615 monitor_openfds(mon, 0); 1616} 1617 1618#ifdef GSSAPI 1619int 1620mm_answer_gss_setup_ctx(int sock, Buffer *m) 1621{ 1622 gss_OID_desc goid; 1623 OM_uint32 major; 1624 u_int len; 1625 1626 goid.elements = buffer_get_string(m, &len); 1627 goid.length = len; 1628 1629 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1630 1631 free(goid.elements); 1632 1633 buffer_clear(m); 1634 buffer_put_int(m, major); 1635 1636 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1637 1638 /* Now we have a context, enable the step */ 1639 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1640 1641 return (0); 1642} 1643 1644int 1645mm_answer_gss_accept_ctx(int sock, Buffer *m) 1646{ 1647 gss_buffer_desc in; 1648 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1649 OM_uint32 major, minor; 1650 OM_uint32 flags = 0; /* GSI needs this */ 1651 u_int len; 1652 1653 in.value = buffer_get_string(m, &len); 1654 in.length = len; 1655 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1656 free(in.value); 1657 1658 buffer_clear(m); 1659 buffer_put_int(m, major); 1660 buffer_put_string(m, out.value, out.length); 1661 buffer_put_int(m, flags); 1662 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1663 1664 gss_release_buffer(&minor, &out); 1665 1666 if (major == GSS_S_COMPLETE) { 1667 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1668 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1669 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1670 } 1671 return (0); 1672} 1673 1674int 1675mm_answer_gss_checkmic(int sock, Buffer *m) 1676{ 1677 gss_buffer_desc gssbuf, mic; 1678 OM_uint32 ret; 1679 u_int len; 1680 1681 gssbuf.value = buffer_get_string(m, &len); 1682 gssbuf.length = len; 1683 mic.value = buffer_get_string(m, &len); 1684 mic.length = len; 1685 1686 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1687 1688 free(gssbuf.value); 1689 free(mic.value); 1690 1691 buffer_clear(m); 1692 buffer_put_int(m, ret); 1693 1694 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1695 1696 if (!GSS_ERROR(ret)) 1697 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1698 1699 return (0); 1700} 1701 1702int 1703mm_answer_gss_userok(int sock, Buffer *m) 1704{ 1705 int authenticated; 1706 1707 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1708 1709 buffer_clear(m); 1710 buffer_put_int(m, authenticated); 1711 1712 debug3("%s: sending result %d", __func__, authenticated); 1713 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1714 1715 auth_method = "gssapi-with-mic"; 1716 1717 /* Monitor loop will terminate if authenticated */ 1718 return (authenticated); 1719} 1720#endif /* GSSAPI */ 1721 1722