1/* $OpenBSD: monitor.c,v 1.240 2024/06/06 17:15:25 djm Exp $ */ 2/* 3 * Copyright 2002 Niels Provos <provos@citi.umich.edu> 4 * Copyright 2002 Markus Friedl <markus@openbsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28#include <sys/types.h> 29#include <sys/wait.h> 30#include <sys/socket.h> 31#include <sys/tree.h> 32#include <sys/queue.h> 33 34#ifdef WITH_OPENSSL 35#include <openssl/dh.h> 36#endif 37 38#include <errno.h> 39#include <fcntl.h> 40#include <limits.h> 41#include <paths.h> 42#include <poll.h> 43#include <pwd.h> 44#include <signal.h> 45#include <stdarg.h> 46#include <stdint.h> 47#include <stdio.h> 48#include <stdlib.h> 49#include <string.h> 50#include <unistd.h> 51 52#include "atomicio.h" 53#include "xmalloc.h" 54#include "ssh.h" 55#include "sshkey.h" 56#include "sshbuf.h" 57#include "hostfile.h" 58#include "auth.h" 59#include "cipher.h" 60#include "kex.h" 61#include "dh.h" 62#include "packet.h" 63#include "auth-options.h" 64#include "sshpty.h" 65#include "channels.h" 66#include "session.h" 67#include "sshlogin.h" 68#include "canohost.h" 69#include "log.h" 70#include "misc.h" 71#include "servconf.h" 72#include "monitor.h" 73#ifdef GSSAPI 74#include "ssh-gss.h" 75#endif 76#include "monitor_wrap.h" 77#include "monitor_fdpass.h" 78#include "compat.h" 79#include "ssh2.h" 80#include "authfd.h" 81#include "match.h" 82#include "ssherr.h" 83#include "sk-api.h" 84 85#ifdef GSSAPI 86static Gssctxt *gsscontext = NULL; 87#endif 88 89/* Imports */ 90extern ServerOptions options; 91extern u_int utmp_len; 92extern struct sshbuf *loginmsg; 93extern struct sshauthopt *auth_opts; /* XXX move to permanent ssh->authctxt? */ 94 95/* State exported from the child */ 96static struct sshbuf *child_state; 97 98/* Functions on the monitor that answer unprivileged requests */ 99 100int mm_answer_moduli(struct ssh *, int, struct sshbuf *); 101int mm_answer_sign(struct ssh *, int, struct sshbuf *); 102int mm_answer_pwnamallow(struct ssh *, int, struct sshbuf *); 103int mm_answer_auth2_read_banner(struct ssh *, int, struct sshbuf *); 104int mm_answer_authserv(struct ssh *, int, struct sshbuf *); 105int mm_answer_authpassword(struct ssh *, int, struct sshbuf *); 106int mm_answer_bsdauthquery(struct ssh *, int, struct sshbuf *); 107int mm_answer_bsdauthrespond(struct ssh *, int, struct sshbuf *); 108int mm_answer_keyallowed(struct ssh *, int, struct sshbuf *); 109int mm_answer_keyverify(struct ssh *, int, struct sshbuf *); 110int mm_answer_pty(struct ssh *, int, struct sshbuf *); 111int mm_answer_pty_cleanup(struct ssh *, int, struct sshbuf *); 112int mm_answer_term(struct ssh *, int, struct sshbuf *); 113 114#ifdef GSSAPI 115int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *); 116int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *); 117int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *); 118int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *); 119#endif 120 121static Authctxt *authctxt; 122 123/* local state for key verify */ 124static u_char *key_blob = NULL; 125static size_t key_bloblen = 0; 126static u_int key_blobtype = MM_NOKEY; 127static struct sshauthopt *key_opts = NULL; 128static char *hostbased_cuser = NULL; 129static char *hostbased_chost = NULL; 130static char *auth_method = "unknown"; 131static char *auth_submethod = NULL; 132static u_int session_id2_len = 0; 133static u_char *session_id2 = NULL; 134static pid_t monitor_child_pid; 135int auth_attempted = 0; 136 137struct mon_table { 138 enum monitor_reqtype type; 139 int flags; 140 int (*f)(struct ssh *, int, struct sshbuf *); 141}; 142 143#define MON_ISAUTH 0x0004 /* Required for Authentication */ 144#define MON_AUTHDECIDE 0x0008 /* Decides Authentication */ 145#define MON_ONCE 0x0010 /* Disable after calling */ 146#define MON_ALOG 0x0020 /* Log auth attempt without authenticating */ 147 148#define MON_AUTH (MON_ISAUTH|MON_AUTHDECIDE) 149 150#define MON_PERMIT 0x1000 /* Request is permitted */ 151 152static int monitor_read(struct ssh *, struct monitor *, struct mon_table *, 153 struct mon_table **); 154static int monitor_read_log(struct monitor *); 155 156struct mon_table mon_dispatch_proto20[] = { 157#ifdef WITH_OPENSSL 158 {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli}, 159#endif 160 {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, 161 {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, 162 {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, 163 {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, 164 {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, 165 {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery}, 166 {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond}, 167 {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed}, 168 {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify}, 169#ifdef GSSAPI 170 {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx}, 171 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx}, 172 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok}, 173 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic}, 174#endif 175 {0, 0, NULL} 176}; 177 178struct mon_table mon_dispatch_postauth20[] = { 179#ifdef WITH_OPENSSL 180 {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, 181#endif 182 {MONITOR_REQ_SIGN, 0, mm_answer_sign}, 183 {MONITOR_REQ_PTY, 0, mm_answer_pty}, 184 {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup}, 185 {MONITOR_REQ_TERM, 0, mm_answer_term}, 186 {0, 0, NULL} 187}; 188 189struct mon_table *mon_dispatch; 190 191/* Specifies if a certain message is allowed at the moment */ 192static void 193monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit) 194{ 195 while (ent->f != NULL) { 196 if (ent->type == type) { 197 ent->flags &= ~MON_PERMIT; 198 ent->flags |= permit ? MON_PERMIT : 0; 199 return; 200 } 201 ent++; 202 } 203} 204 205static void 206monitor_permit_authentications(int permit) 207{ 208 struct mon_table *ent = mon_dispatch; 209 210 while (ent->f != NULL) { 211 if (ent->flags & MON_AUTH) { 212 ent->flags &= ~MON_PERMIT; 213 ent->flags |= permit ? MON_PERMIT : 0; 214 } 215 ent++; 216 } 217} 218 219void 220monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor) 221{ 222 struct mon_table *ent; 223 int authenticated = 0, partial = 0; 224 225 debug3("preauth child monitor started"); 226 227 if (pmonitor->m_recvfd >= 0) 228 close(pmonitor->m_recvfd); 229 if (pmonitor->m_log_sendfd >= 0) 230 close(pmonitor->m_log_sendfd); 231 pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; 232 233 authctxt = (Authctxt *)ssh->authctxt; 234 memset(authctxt, 0, sizeof(*authctxt)); 235 ssh->authctxt = authctxt; 236 237 mon_dispatch = mon_dispatch_proto20; 238 /* Permit requests for moduli and signatures */ 239 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 240 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 241 242 /* The first few requests do not require asynchronous access */ 243 while (!authenticated) { 244 partial = 0; 245 auth_method = "unknown"; 246 auth_submethod = NULL; 247 auth2_authctxt_reset_info(authctxt); 248 249 authenticated = (monitor_read(ssh, pmonitor, 250 mon_dispatch, &ent) == 1); 251 252 /* Record that auth was attempted to set exit status later */ 253 if ((ent->flags & MON_AUTH) != 0) 254 auth_attempted = 1; 255 256 /* Special handling for multiple required authentications */ 257 if (options.num_auth_methods != 0) { 258 if (authenticated && 259 !auth2_update_methods_lists(authctxt, 260 auth_method, auth_submethod)) { 261 debug3_f("method %s: partial", auth_method); 262 authenticated = 0; 263 partial = 1; 264 } 265 } 266 267 if (authenticated) { 268 if (!(ent->flags & MON_AUTHDECIDE)) 269 fatal_f("unexpected authentication from %d", 270 ent->type); 271 if (authctxt->pw->pw_uid == 0 && 272 !auth_root_allowed(ssh, auth_method)) 273 authenticated = 0; 274 } 275 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { 276 auth_log(ssh, authenticated, partial, 277 auth_method, auth_submethod); 278 if (!partial && !authenticated) 279 authctxt->failures++; 280 if (authenticated || partial) { 281 auth2_update_session_info(authctxt, 282 auth_method, auth_submethod); 283 } 284 } 285 if (authctxt->failures > options.max_authtries) { 286 /* Shouldn't happen */ 287 fatal_f("privsep child made too many authentication " 288 "attempts"); 289 } 290 } 291 292 if (!authctxt->valid) 293 fatal_f("authenticated invalid user"); 294 if (strcmp(auth_method, "unknown") == 0) 295 fatal_f("authentication method name unknown"); 296 297 debug_f("user %s authenticated by privileged process", authctxt->user); 298 auth_attempted = 0; 299 ssh->authctxt = NULL; 300 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 301 302 mm_get_keystate(ssh, pmonitor); 303 304 /* Drain any buffered messages from the child */ 305 while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) 306 ; 307 308 if (pmonitor->m_recvfd >= 0) 309 close(pmonitor->m_recvfd); 310 if (pmonitor->m_log_sendfd >= 0) 311 close(pmonitor->m_log_sendfd); 312 pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; 313} 314 315static void 316monitor_set_child_handler(pid_t pid) 317{ 318 monitor_child_pid = pid; 319} 320 321static void 322monitor_child_handler(int sig) 323{ 324 kill(monitor_child_pid, sig); 325} 326 327void 328monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor) 329{ 330 close(pmonitor->m_recvfd); 331 pmonitor->m_recvfd = -1; 332 333 monitor_set_child_handler(pmonitor->m_pid); 334 ssh_signal(SIGHUP, &monitor_child_handler); 335 ssh_signal(SIGTERM, &monitor_child_handler); 336 ssh_signal(SIGINT, &monitor_child_handler); 337 338 mon_dispatch = mon_dispatch_postauth20; 339 340 /* Permit requests for moduli and signatures */ 341 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); 342 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); 343 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); 344 345 if (auth_opts->permit_pty_flag) { 346 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1); 347 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1); 348 } 349 350 for (;;) 351 monitor_read(ssh, pmonitor, mon_dispatch, NULL); 352} 353 354static int 355monitor_read_log(struct monitor *pmonitor) 356{ 357 struct sshbuf *logmsg; 358 u_int len, level, forced; 359 char *msg; 360 u_char *p; 361 int r; 362 363 if ((logmsg = sshbuf_new()) == NULL) 364 fatal_f("sshbuf_new"); 365 366 /* Read length */ 367 if ((r = sshbuf_reserve(logmsg, 4, &p)) != 0) 368 fatal_fr(r, "reserve len"); 369 if (atomicio(read, pmonitor->m_log_recvfd, p, 4) != 4) { 370 if (errno == EPIPE) { 371 sshbuf_free(logmsg); 372 debug_f("child log fd closed"); 373 close(pmonitor->m_log_recvfd); 374 pmonitor->m_log_recvfd = -1; 375 return -1; 376 } 377 fatal_f("log fd read: %s", strerror(errno)); 378 } 379 if ((r = sshbuf_get_u32(logmsg, &len)) != 0) 380 fatal_fr(r, "parse len"); 381 if (len <= 4 || len > 8192) 382 fatal_f("invalid log message length %u", len); 383 384 /* Read severity, message */ 385 sshbuf_reset(logmsg); 386 if ((r = sshbuf_reserve(logmsg, len, &p)) != 0) 387 fatal_fr(r, "reserve msg"); 388 if (atomicio(read, pmonitor->m_log_recvfd, p, len) != len) 389 fatal_f("log fd read: %s", strerror(errno)); 390 if ((r = sshbuf_get_u32(logmsg, &level)) != 0 || 391 (r = sshbuf_get_u32(logmsg, &forced)) != 0 || 392 (r = sshbuf_get_cstring(logmsg, &msg, NULL)) != 0) 393 fatal_fr(r, "parse"); 394 395 /* Log it */ 396 if (log_level_name(level) == NULL) 397 fatal_f("invalid log level %u (corrupted message?)", level); 398 sshlogdirect(level, forced, "%s [preauth]", msg); 399 400 sshbuf_free(logmsg); 401 free(msg); 402 403 return 0; 404} 405 406static int 407monitor_read(struct ssh *ssh, struct monitor *pmonitor, struct mon_table *ent, 408 struct mon_table **pent) 409{ 410 struct sshbuf *m; 411 int r, ret; 412 u_char type; 413 struct pollfd pfd[2]; 414 415 for (;;) { 416 memset(&pfd, 0, sizeof(pfd)); 417 pfd[0].fd = pmonitor->m_sendfd; 418 pfd[0].events = POLLIN; 419 pfd[1].fd = pmonitor->m_log_recvfd; 420 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN; 421 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) { 422 if (errno == EINTR || errno == EAGAIN) 423 continue; 424 fatal_f("poll: %s", strerror(errno)); 425 } 426 if (pfd[1].revents) { 427 /* 428 * Drain all log messages before processing next 429 * monitor request. 430 */ 431 monitor_read_log(pmonitor); 432 continue; 433 } 434 if (pfd[0].revents) 435 break; /* Continues below */ 436 } 437 438 if ((m = sshbuf_new()) == NULL) 439 fatal_f("sshbuf_new"); 440 441 mm_request_receive(pmonitor->m_sendfd, m); 442 if ((r = sshbuf_get_u8(m, &type)) != 0) 443 fatal_fr(r, "parse type"); 444 445 debug3_f("checking request %d", type); 446 447 while (ent->f != NULL) { 448 if (ent->type == type) 449 break; 450 ent++; 451 } 452 453 if (ent->f != NULL) { 454 if (!(ent->flags & MON_PERMIT)) 455 fatal_f("unpermitted request %d", type); 456 ret = (*ent->f)(ssh, pmonitor->m_sendfd, m); 457 sshbuf_free(m); 458 459 /* The child may use this request only once, disable it */ 460 if (ent->flags & MON_ONCE) { 461 debug2_f("%d used once, disabling now", type); 462 ent->flags &= ~MON_PERMIT; 463 } 464 465 if (pent != NULL) 466 *pent = ent; 467 468 return ret; 469 } 470 471 fatal_f("unsupported request: %d", type); 472 473 /* NOTREACHED */ 474 return (-1); 475} 476 477/* allowed key state */ 478static int 479monitor_allowed_key(const u_char *blob, u_int bloblen) 480{ 481 /* make sure key is allowed */ 482 if (key_blob == NULL || key_bloblen != bloblen || 483 timingsafe_bcmp(key_blob, blob, key_bloblen)) 484 return (0); 485 return (1); 486} 487 488static void 489monitor_reset_key_state(void) 490{ 491 /* reset state */ 492 free(key_blob); 493 free(hostbased_cuser); 494 free(hostbased_chost); 495 sshauthopt_free(key_opts); 496 key_blob = NULL; 497 key_bloblen = 0; 498 key_blobtype = MM_NOKEY; 499 key_opts = NULL; 500 hostbased_cuser = NULL; 501 hostbased_chost = NULL; 502} 503 504#ifdef WITH_OPENSSL 505int 506mm_answer_moduli(struct ssh *ssh, int sock, struct sshbuf *m) 507{ 508 DH *dh; 509 const BIGNUM *dh_p, *dh_g; 510 int r; 511 u_int min, want, max; 512 513 if ((r = sshbuf_get_u32(m, &min)) != 0 || 514 (r = sshbuf_get_u32(m, &want)) != 0 || 515 (r = sshbuf_get_u32(m, &max)) != 0) 516 fatal_fr(r, "parse"); 517 518 debug3_f("got parameters: %d %d %d", min, want, max); 519 /* We need to check here, too, in case the child got corrupted */ 520 if (max < min || want < min || max < want) 521 fatal_f("bad parameters: %d %d %d", min, want, max); 522 523 sshbuf_reset(m); 524 525 dh = choose_dh(min, want, max); 526 if (dh == NULL) { 527 if ((r = sshbuf_put_u8(m, 0)) != 0) 528 fatal_fr(r, "assemble empty"); 529 return (0); 530 } else { 531 /* Send first bignum */ 532 DH_get0_pqg(dh, &dh_p, NULL, &dh_g); 533 if ((r = sshbuf_put_u8(m, 1)) != 0 || 534 (r = sshbuf_put_bignum2(m, dh_p)) != 0 || 535 (r = sshbuf_put_bignum2(m, dh_g)) != 0) 536 fatal_fr(r, "assemble"); 537 538 DH_free(dh); 539 } 540 mm_request_send(sock, MONITOR_ANS_MODULI, m); 541 return (0); 542} 543#endif 544 545int 546mm_answer_sign(struct ssh *ssh, int sock, struct sshbuf *m) 547{ 548 extern int auth_sock; /* XXX move to state struct? */ 549 struct sshkey *key; 550 struct sshbuf *sigbuf = NULL; 551 u_char *p = NULL, *signature = NULL; 552 char *alg = NULL; 553 size_t datlen, siglen, alglen; 554 int r, is_proof = 0; 555 u_int keyid, compat; 556 const char proof_req[] = "hostkeys-prove-00@openssh.com"; 557 558 debug3_f("entering"); 559 560 if ((r = sshbuf_get_u32(m, &keyid)) != 0 || 561 (r = sshbuf_get_string(m, &p, &datlen)) != 0 || 562 (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0 || 563 (r = sshbuf_get_u32(m, &compat)) != 0) 564 fatal_fr(r, "parse"); 565 if (keyid > INT_MAX) 566 fatal_f("invalid key ID"); 567 568 /* 569 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes), 570 * SHA384 (48 bytes) and SHA512 (64 bytes). 571 * 572 * Otherwise, verify the signature request is for a hostkey 573 * proof. 574 * 575 * XXX perform similar check for KEX signature requests too? 576 * it's not trivial, since what is signed is the hash, rather 577 * than the full kex structure... 578 */ 579 if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) { 580 /* 581 * Construct expected hostkey proof and compare it to what 582 * the client sent us. 583 */ 584 if (session_id2_len == 0) /* hostkeys is never first */ 585 fatal_f("bad data length: %zu", datlen); 586 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL) 587 fatal_f("no hostkey for index %d", keyid); 588 if ((sigbuf = sshbuf_new()) == NULL) 589 fatal_f("sshbuf_new"); 590 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 || 591 (r = sshbuf_put_string(sigbuf, session_id2, 592 session_id2_len)) != 0 || 593 (r = sshkey_puts(key, sigbuf)) != 0) 594 fatal_fr(r, "assemble private key proof"); 595 if (datlen != sshbuf_len(sigbuf) || 596 memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0) 597 fatal_f("bad data length: %zu, hostkey proof len %zu", 598 datlen, sshbuf_len(sigbuf)); 599 sshbuf_free(sigbuf); 600 is_proof = 1; 601 } 602 603 /* save session id, it will be passed on the first call */ 604 if (session_id2_len == 0) { 605 session_id2_len = datlen; 606 session_id2 = xmalloc(session_id2_len); 607 memcpy(session_id2, p, session_id2_len); 608 } 609 610 if ((key = get_hostkey_by_index(keyid)) != NULL) { 611 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg, 612 options.sk_provider, NULL, compat)) != 0) 613 fatal_fr(r, "sign"); 614 } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL && 615 auth_sock > 0) { 616 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen, 617 p, datlen, alg, compat)) != 0) 618 fatal_fr(r, "agent sign"); 619 } else 620 fatal_f("no hostkey from index %d", keyid); 621 622 debug3_f("%s %s signature len=%zu", alg, 623 is_proof ? "hostkey proof" : "KEX", siglen); 624 625 sshbuf_reset(m); 626 if ((r = sshbuf_put_string(m, signature, siglen)) != 0) 627 fatal_fr(r, "assemble"); 628 629 free(alg); 630 free(p); 631 free(signature); 632 633 mm_request_send(sock, MONITOR_ANS_SIGN, m); 634 635 /* Turn on permissions for getpwnam */ 636 monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); 637 638 return (0); 639} 640 641#define PUTPW(b, id) \ 642 do { \ 643 if ((r = sshbuf_put_string(b, \ 644 &pwent->id, sizeof(pwent->id))) != 0) \ 645 fatal_fr(r, "assemble %s", #id); \ 646 } while (0) 647 648void 649mm_encode_server_options(struct sshbuf *m) 650{ 651 int r; 652 u_int i; 653 654 /* XXX this leaks raw pointers to the unpriv child processes */ 655 if ((r = sshbuf_put_string(m, &options, sizeof(options))) != 0) 656 fatal_fr(r, "assemble options"); 657 658#define M_CP_STROPT(x) do { \ 659 if (options.x != NULL && \ 660 (r = sshbuf_put_cstring(m, options.x)) != 0) \ 661 fatal_fr(r, "assemble %s", #x); \ 662 } while (0) 663#define M_CP_STRARRAYOPT(x, nx) do { \ 664 for (i = 0; i < options.nx; i++) { \ 665 if ((r = sshbuf_put_cstring(m, options.x[i])) != 0) \ 666 fatal_fr(r, "assemble %s", #x); \ 667 } \ 668 } while (0) 669 /* See comment in servconf.h */ 670 COPY_MATCH_STRING_OPTS(); 671#undef M_CP_STROPT 672#undef M_CP_STRARRAYOPT 673} 674 675/* Retrieves the password entry and also checks if the user is permitted */ 676int 677mm_answer_pwnamallow(struct ssh *ssh, int sock, struct sshbuf *m) 678{ 679 struct passwd *pwent; 680 int r, allowed = 0; 681 682 debug3_f("entering"); 683 684 if (authctxt->attempt++ != 0) 685 fatal_f("multiple attempts for getpwnam"); 686 687 if ((r = sshbuf_get_cstring(m, &authctxt->user, NULL)) != 0) 688 fatal_fr(r, "parse"); 689 690 pwent = getpwnamallow(ssh, authctxt->user); 691 692 setproctitle("%s [priv]", pwent ? authctxt->user : "unknown"); 693 694 sshbuf_reset(m); 695 696 if (pwent == NULL) { 697 if ((r = sshbuf_put_u8(m, 0)) != 0) 698 fatal_fr(r, "assemble fakepw"); 699 authctxt->pw = fakepw(); 700 goto out; 701 } 702 703 allowed = 1; 704 authctxt->pw = pwent; 705 authctxt->valid = 1; 706 707 /* XXX send fake class/dir/shell, etc. */ 708 if ((r = sshbuf_put_u8(m, 1)) != 0) 709 fatal_fr(r, "assemble ok"); 710 PUTPW(m, pw_uid); 711 PUTPW(m, pw_gid); 712 PUTPW(m, pw_change); 713 PUTPW(m, pw_expire); 714 if ((r = sshbuf_put_cstring(m, pwent->pw_name)) != 0 || 715 (r = sshbuf_put_cstring(m, "*")) != 0 || 716 (r = sshbuf_put_cstring(m, pwent->pw_gecos)) != 0 || 717 (r = sshbuf_put_cstring(m, pwent->pw_class)) != 0 || 718 (r = sshbuf_put_cstring(m, pwent->pw_dir)) != 0 || 719 (r = sshbuf_put_cstring(m, pwent->pw_shell)) != 0) 720 fatal_fr(r, "assemble pw"); 721 722 out: 723 ssh_packet_set_log_preamble(ssh, "%suser %s", 724 authctxt->valid ? "authenticating" : "invalid ", authctxt->user); 725 726 /* Send active options to unpriv */ 727 mm_encode_server_options(m); 728 729 /* Create valid auth method lists */ 730 if (auth2_setup_methods_lists(authctxt) != 0) { 731 /* 732 * The monitor will continue long enough to let the child 733 * run to its packet_disconnect(), but it must not allow any 734 * authentication to succeed. 735 */ 736 debug_f("no valid authentication method lists"); 737 } 738 739 debug3_f("sending MONITOR_ANS_PWNAM: %d", allowed); 740 mm_request_send(sock, MONITOR_ANS_PWNAM, m); 741 742 /* Allow service/style information on the auth context */ 743 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); 744 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); 745 746 return (0); 747} 748 749int mm_answer_auth2_read_banner(struct ssh *ssh, int sock, struct sshbuf *m) 750{ 751 char *banner; 752 int r; 753 754 sshbuf_reset(m); 755 banner = auth2_read_banner(); 756 if ((r = sshbuf_put_cstring(m, banner != NULL ? banner : "")) != 0) 757 fatal_fr(r, "assemble"); 758 mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m); 759 free(banner); 760 761 return (0); 762} 763 764int 765mm_answer_authserv(struct ssh *ssh, int sock, struct sshbuf *m) 766{ 767 int r; 768 769 monitor_permit_authentications(1); 770 771 if ((r = sshbuf_get_cstring(m, &authctxt->service, NULL)) != 0 || 772 (r = sshbuf_get_cstring(m, &authctxt->style, NULL)) != 0) 773 fatal_fr(r, "parse"); 774 debug3_f("service=%s, style=%s", authctxt->service, authctxt->style); 775 776 if (strlen(authctxt->style) == 0) { 777 free(authctxt->style); 778 authctxt->style = NULL; 779 } 780 781 return (0); 782} 783 784int 785mm_answer_authpassword(struct ssh *ssh, int sock, struct sshbuf *m) 786{ 787 static int call_count; 788 char *passwd; 789 int r, authenticated; 790 size_t plen; 791 792 if (!options.password_authentication) 793 fatal_f("password authentication not enabled"); 794 if ((r = sshbuf_get_cstring(m, &passwd, &plen)) != 0) 795 fatal_fr(r, "parse"); 796 /* Only authenticate if the context is valid */ 797 authenticated = options.password_authentication && 798 auth_password(ssh, passwd); 799 freezero(passwd, plen); 800 801 sshbuf_reset(m); 802 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 803 fatal_fr(r, "assemble"); 804 805 debug3_f("sending result %d", authenticated); 806 mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); 807 808 call_count++; 809 if (plen == 0 && call_count == 1) 810 auth_method = "none"; 811 else 812 auth_method = "password"; 813 814 /* Causes monitor loop to terminate if authenticated */ 815 return (authenticated); 816} 817 818int 819mm_answer_bsdauthquery(struct ssh *ssh, int sock, struct sshbuf *m) 820{ 821 char *name, *infotxt; 822 u_int numprompts, *echo_on, success; 823 char **prompts; 824 int r; 825 826 if (!options.kbd_interactive_authentication) 827 fatal_f("kbd-int authentication not enabled"); 828 success = bsdauth_query(authctxt, &name, &infotxt, &numprompts, 829 &prompts, &echo_on) < 0 ? 0 : 1; 830 831 sshbuf_reset(m); 832 if ((r = sshbuf_put_u32(m, success)) != 0) 833 fatal_fr(r, "assemble"); 834 if (success) { 835 if ((r = sshbuf_put_cstring(m, prompts[0])) != 0) 836 fatal_fr(r, "assemble prompt"); 837 } 838 839 debug3_f("sending challenge success: %u", success); 840 mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m); 841 842 if (success) { 843 free(name); 844 free(infotxt); 845 free(prompts); 846 free(echo_on); 847 } 848 849 return (0); 850} 851 852int 853mm_answer_bsdauthrespond(struct ssh *ssh, int sock, struct sshbuf *m) 854{ 855 char *response; 856 int r, authok; 857 858 if (!options.kbd_interactive_authentication) 859 fatal_f("kbd-int authentication not enabled"); 860 if (authctxt->as == NULL) 861 fatal_f("no bsd auth session"); 862 863 if ((r = sshbuf_get_cstring(m, &response, NULL)) != 0) 864 fatal_fr(r, "parse"); 865 authok = options.kbd_interactive_authentication && 866 auth_userresponse(authctxt->as, response, 0); 867 authctxt->as = NULL; 868 debug3_f("<%s> = <%d>", response, authok); 869 free(response); 870 871 sshbuf_reset(m); 872 if ((r = sshbuf_put_u32(m, authok)) != 0) 873 fatal_fr(r, "assemble"); 874 875 debug3_f("sending authenticated: %d", authok); 876 mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m); 877 878 auth_method = "keyboard-interactive"; 879 auth_submethod = "bsdauth"; 880 881 return (authok != 0); 882} 883 884/* 885 * Check that the key type appears in the supplied pattern list, ignoring 886 * mismatches in the signature algorithm. (Signature algorithm checks are 887 * performed in the unprivileged authentication code). 888 * Returns 1 on success, 0 otherwise. 889 */ 890static int 891key_base_type_match(const char *method, const struct sshkey *key, 892 const char *list) 893{ 894 char *s, *l, *ol = xstrdup(list); 895 int found = 0; 896 897 l = ol; 898 for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) { 899 if (sshkey_type_from_name(s) == key->type) { 900 found = 1; 901 break; 902 } 903 } 904 if (!found) { 905 error("%s key type %s is not in permitted list %s", method, 906 sshkey_ssh_name(key), list); 907 } 908 909 free(ol); 910 return found; 911} 912 913int 914mm_answer_keyallowed(struct ssh *ssh, int sock, struct sshbuf *m) 915{ 916 struct sshkey *key = NULL; 917 char *cuser, *chost; 918 u_int pubkey_auth_attempt; 919 u_int type = 0; 920 int r, allowed = 0; 921 struct sshauthopt *opts = NULL; 922 923 debug3_f("entering"); 924 if ((r = sshbuf_get_u32(m, &type)) != 0 || 925 (r = sshbuf_get_cstring(m, &cuser, NULL)) != 0 || 926 (r = sshbuf_get_cstring(m, &chost, NULL)) != 0 || 927 (r = sshkey_froms(m, &key)) != 0 || 928 (r = sshbuf_get_u32(m, &pubkey_auth_attempt)) != 0) 929 fatal_fr(r, "parse"); 930 931 if (key != NULL && authctxt->valid) { 932 switch (type) { 933 case MM_USERKEY: 934 auth_method = "publickey"; 935 if (!options.pubkey_authentication) 936 break; 937 if (auth2_key_already_used(authctxt, key)) 938 break; 939 if (!key_base_type_match(auth_method, key, 940 options.pubkey_accepted_algos)) 941 break; 942 allowed = user_key_allowed(ssh, authctxt->pw, key, 943 pubkey_auth_attempt, &opts); 944 break; 945 case MM_HOSTKEY: 946 auth_method = "hostbased"; 947 if (!options.hostbased_authentication) 948 break; 949 if (auth2_key_already_used(authctxt, key)) 950 break; 951 if (!key_base_type_match(auth_method, key, 952 options.hostbased_accepted_algos)) 953 break; 954 allowed = hostbased_key_allowed(ssh, authctxt->pw, 955 cuser, chost, key); 956 auth2_record_info(authctxt, 957 "client user \"%.100s\", client host \"%.100s\"", 958 cuser, chost); 959 break; 960 default: 961 fatal_f("unknown key type %u", type); 962 break; 963 } 964 } 965 966 debug3_f("%s authentication%s: %s key is %s", auth_method, 967 pubkey_auth_attempt ? "" : " test", 968 (key == NULL || !authctxt->valid) ? "invalid" : sshkey_type(key), 969 allowed ? "allowed" : "not allowed"); 970 971 auth2_record_key(authctxt, 0, key); 972 973 /* clear temporarily storage (used by verify) */ 974 monitor_reset_key_state(); 975 976 if (allowed) { 977 /* Save temporarily for comparison in verify */ 978 if ((r = sshkey_to_blob(key, &key_blob, &key_bloblen)) != 0) 979 fatal_fr(r, "sshkey_to_blob"); 980 key_blobtype = type; 981 key_opts = opts; 982 hostbased_cuser = cuser; 983 hostbased_chost = chost; 984 } else { 985 /* Log failed attempt */ 986 auth_log(ssh, 0, 0, auth_method, NULL); 987 free(cuser); 988 free(chost); 989 } 990 sshkey_free(key); 991 992 sshbuf_reset(m); 993 if ((r = sshbuf_put_u32(m, allowed)) != 0) 994 fatal_fr(r, "assemble"); 995 if (opts != NULL && (r = sshauthopt_serialise(opts, m, 1)) != 0) 996 fatal_fr(r, "sshauthopt_serialise"); 997 mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m); 998 999 if (!allowed) 1000 sshauthopt_free(opts); 1001 1002 return (0); 1003} 1004 1005static int 1006monitor_valid_userblob(struct ssh *ssh, const u_char *data, u_int datalen) 1007{ 1008 struct sshbuf *b; 1009 struct sshkey *hostkey = NULL; 1010 const u_char *p; 1011 char *userstyle, *cp; 1012 size_t len; 1013 u_char type; 1014 int hostbound = 0, r, fail = 0; 1015 1016 if ((b = sshbuf_from(data, datalen)) == NULL) 1017 fatal_f("sshbuf_from"); 1018 1019 if (ssh->compat & SSH_OLD_SESSIONID) { 1020 p = sshbuf_ptr(b); 1021 len = sshbuf_len(b); 1022 if ((session_id2 == NULL) || 1023 (len < session_id2_len) || 1024 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1025 fail++; 1026 if ((r = sshbuf_consume(b, session_id2_len)) != 0) 1027 fatal_fr(r, "consume"); 1028 } else { 1029 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1030 fatal_fr(r, "parse sessionid"); 1031 if ((session_id2 == NULL) || 1032 (len != session_id2_len) || 1033 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1034 fail++; 1035 } 1036 if ((r = sshbuf_get_u8(b, &type)) != 0) 1037 fatal_fr(r, "parse type"); 1038 if (type != SSH2_MSG_USERAUTH_REQUEST) 1039 fail++; 1040 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1041 fatal_fr(r, "parse userstyle"); 1042 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1043 authctxt->style ? ":" : "", 1044 authctxt->style ? authctxt->style : ""); 1045 if (strcmp(userstyle, cp) != 0) { 1046 logit("wrong user name passed to monitor: " 1047 "expected %s != %.100s", userstyle, cp); 1048 fail++; 1049 } 1050 free(userstyle); 1051 free(cp); 1052 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1053 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1054 fatal_fr(r, "parse method"); 1055 if (strcmp("publickey", cp) != 0) { 1056 if (strcmp("publickey-hostbound-v00@openssh.com", cp) == 0) 1057 hostbound = 1; 1058 else 1059 fail++; 1060 } 1061 free(cp); 1062 if ((r = sshbuf_get_u8(b, &type)) != 0) 1063 fatal_fr(r, "parse pktype"); 1064 if (type == 0) 1065 fail++; 1066 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1067 (r = sshbuf_skip_string(b)) != 0 || /* pkblob */ 1068 (hostbound && (r = sshkey_froms(b, &hostkey)) != 0)) 1069 fatal_fr(r, "parse pk"); 1070 if (sshbuf_len(b) != 0) 1071 fail++; 1072 sshbuf_free(b); 1073 if (hostkey != NULL) { 1074 /* 1075 * Ensure this is actually one of our hostkeys; unfortunately 1076 * can't check ssh->kex->initial_hostkey directly at this point 1077 * as packet state has not yet been exported to monitor. 1078 */ 1079 if (get_hostkey_index(hostkey, 1, ssh) == -1) 1080 fatal_f("hostbound hostkey does not match"); 1081 sshkey_free(hostkey); 1082 } 1083 return (fail == 0); 1084} 1085 1086static int 1087monitor_valid_hostbasedblob(const u_char *data, u_int datalen, 1088 const char *cuser, const char *chost) 1089{ 1090 struct sshbuf *b; 1091 const u_char *p; 1092 char *cp, *userstyle; 1093 size_t len; 1094 int r, fail = 0; 1095 u_char type; 1096 1097 if ((b = sshbuf_from(data, datalen)) == NULL) 1098 fatal_f("sshbuf_new"); 1099 if ((r = sshbuf_get_string_direct(b, &p, &len)) != 0) 1100 fatal_fr(r, "parse sessionid"); 1101 1102 if ((session_id2 == NULL) || 1103 (len != session_id2_len) || 1104 (timingsafe_bcmp(p, session_id2, session_id2_len) != 0)) 1105 fail++; 1106 1107 if ((r = sshbuf_get_u8(b, &type)) != 0) 1108 fatal_fr(r, "parse type"); 1109 if (type != SSH2_MSG_USERAUTH_REQUEST) 1110 fail++; 1111 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1112 fatal_fr(r, "parse userstyle"); 1113 xasprintf(&userstyle, "%s%s%s", authctxt->user, 1114 authctxt->style ? ":" : "", 1115 authctxt->style ? authctxt->style : ""); 1116 if (strcmp(userstyle, cp) != 0) { 1117 logit("wrong user name passed to monitor: " 1118 "expected %s != %.100s", userstyle, cp); 1119 fail++; 1120 } 1121 free(userstyle); 1122 free(cp); 1123 if ((r = sshbuf_skip_string(b)) != 0 || /* service */ 1124 (r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1125 fatal_fr(r, "parse method"); 1126 if (strcmp(cp, "hostbased") != 0) 1127 fail++; 1128 free(cp); 1129 if ((r = sshbuf_skip_string(b)) != 0 || /* pkalg */ 1130 (r = sshbuf_skip_string(b)) != 0) /* pkblob */ 1131 fatal_fr(r, "parse pk"); 1132 1133 /* verify client host, strip trailing dot if necessary */ 1134 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1135 fatal_fr(r, "parse host"); 1136 if (((len = strlen(cp)) > 0) && cp[len - 1] == '.') 1137 cp[len - 1] = '\0'; 1138 if (strcmp(cp, chost) != 0) 1139 fail++; 1140 free(cp); 1141 1142 /* verify client user */ 1143 if ((r = sshbuf_get_cstring(b, &cp, NULL)) != 0) 1144 fatal_fr(r, "parse ruser"); 1145 if (strcmp(cp, cuser) != 0) 1146 fail++; 1147 free(cp); 1148 1149 if (sshbuf_len(b) != 0) 1150 fail++; 1151 sshbuf_free(b); 1152 return (fail == 0); 1153} 1154 1155int 1156mm_answer_keyverify(struct ssh *ssh, int sock, struct sshbuf *m) 1157{ 1158 struct sshkey *key; 1159 const u_char *signature, *data, *blob; 1160 char *sigalg = NULL, *fp = NULL; 1161 size_t signaturelen, datalen, bloblen; 1162 int r, ret, req_presence = 0, req_verify = 0, valid_data = 0; 1163 int encoded_ret; 1164 struct sshkey_sig_details *sig_details = NULL; 1165 1166 if ((r = sshbuf_get_string_direct(m, &blob, &bloblen)) != 0 || 1167 (r = sshbuf_get_string_direct(m, &signature, &signaturelen)) != 0 || 1168 (r = sshbuf_get_string_direct(m, &data, &datalen)) != 0 || 1169 (r = sshbuf_get_cstring(m, &sigalg, NULL)) != 0) 1170 fatal_fr(r, "parse"); 1171 1172 if (hostbased_cuser == NULL || hostbased_chost == NULL || 1173 !monitor_allowed_key(blob, bloblen)) 1174 fatal_f("bad key, not previously allowed"); 1175 1176 /* Empty signature algorithm means NULL. */ 1177 if (*sigalg == '\0') { 1178 free(sigalg); 1179 sigalg = NULL; 1180 } 1181 1182 /* XXX use sshkey_froms here; need to change key_blob, etc. */ 1183 if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0) 1184 fatal_fr(r, "parse key"); 1185 1186 switch (key_blobtype) { 1187 case MM_USERKEY: 1188 valid_data = monitor_valid_userblob(ssh, data, datalen); 1189 auth_method = "publickey"; 1190 break; 1191 case MM_HOSTKEY: 1192 valid_data = monitor_valid_hostbasedblob(data, datalen, 1193 hostbased_cuser, hostbased_chost); 1194 auth_method = "hostbased"; 1195 break; 1196 default: 1197 valid_data = 0; 1198 break; 1199 } 1200 if (!valid_data) 1201 fatal_f("bad %s signature data blob", 1202 key_blobtype == MM_USERKEY ? "userkey" : 1203 (key_blobtype == MM_HOSTKEY ? "hostkey" : "unknown")); 1204 1205 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 1206 SSH_FP_DEFAULT)) == NULL) 1207 fatal_f("sshkey_fingerprint failed"); 1208 1209 ret = sshkey_verify(key, signature, signaturelen, data, datalen, 1210 sigalg, ssh->compat, &sig_details); 1211 debug3_f("%s %s signature using %s %s%s%s", auth_method, 1212 sshkey_type(key), sigalg == NULL ? "default" : sigalg, 1213 (ret == 0) ? "verified" : "unverified", 1214 (ret != 0) ? ": " : "", (ret != 0) ? ssh_err(ret) : ""); 1215 1216 if (ret == 0 && key_blobtype == MM_USERKEY && sig_details != NULL) { 1217 req_presence = (options.pubkey_auth_options & 1218 PUBKEYAUTH_TOUCH_REQUIRED) || 1219 !key_opts->no_require_user_presence; 1220 if (req_presence && 1221 (sig_details->sk_flags & SSH_SK_USER_PRESENCE_REQD) == 0) { 1222 error("public key %s %s signature for %s%s from %.128s " 1223 "port %d rejected: user presence " 1224 "(authenticator touch) requirement not met ", 1225 sshkey_type(key), fp, 1226 authctxt->valid ? "" : "invalid user ", 1227 authctxt->user, ssh_remote_ipaddr(ssh), 1228 ssh_remote_port(ssh)); 1229 ret = SSH_ERR_SIGNATURE_INVALID; 1230 } 1231 req_verify = (options.pubkey_auth_options & 1232 PUBKEYAUTH_VERIFY_REQUIRED) || key_opts->require_verify; 1233 if (req_verify && 1234 (sig_details->sk_flags & SSH_SK_USER_VERIFICATION_REQD) == 0) { 1235 error("public key %s %s signature for %s%s from %.128s " 1236 "port %d rejected: user verification requirement " 1237 "not met ", sshkey_type(key), fp, 1238 authctxt->valid ? "" : "invalid user ", 1239 authctxt->user, ssh_remote_ipaddr(ssh), 1240 ssh_remote_port(ssh)); 1241 ret = SSH_ERR_SIGNATURE_INVALID; 1242 } 1243 } 1244 auth2_record_key(authctxt, ret == 0, key); 1245 1246 if (key_blobtype == MM_USERKEY) 1247 auth_activate_options(ssh, key_opts); 1248 monitor_reset_key_state(); 1249 1250 sshbuf_reset(m); 1251 1252 /* encode ret != 0 as positive integer, since we're sending u32 */ 1253 encoded_ret = (ret != 0); 1254 if ((r = sshbuf_put_u32(m, encoded_ret)) != 0 || 1255 (r = sshbuf_put_u8(m, sig_details != NULL)) != 0) 1256 fatal_fr(r, "assemble"); 1257 if (sig_details != NULL) { 1258 if ((r = sshbuf_put_u32(m, sig_details->sk_counter)) != 0 || 1259 (r = sshbuf_put_u8(m, sig_details->sk_flags)) != 0) 1260 fatal_fr(r, "assemble sk"); 1261 } 1262 sshkey_sig_details_free(sig_details); 1263 mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m); 1264 1265 free(sigalg); 1266 free(fp); 1267 sshkey_free(key); 1268 1269 return ret == 0; 1270} 1271 1272static void 1273mm_record_login(struct ssh *ssh, Session *s, struct passwd *pw) 1274{ 1275 socklen_t fromlen; 1276 struct sockaddr_storage from; 1277 1278 /* 1279 * Get IP address of client. If the connection is not a socket, let 1280 * the address be 0.0.0.0. 1281 */ 1282 memset(&from, 0, sizeof(from)); 1283 fromlen = sizeof(from); 1284 if (ssh_packet_connection_is_on_socket(ssh)) { 1285 if (getpeername(ssh_packet_get_connection_in(ssh), 1286 (struct sockaddr *)&from, &fromlen) == -1) { 1287 debug("getpeername: %.100s", strerror(errno)); 1288 cleanup_exit(255); 1289 } 1290 } 1291 /* Record that there was a login on that tty from the remote host. */ 1292 record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid, 1293 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 1294 (struct sockaddr *)&from, fromlen); 1295} 1296 1297static void 1298mm_session_close(Session *s) 1299{ 1300 debug3_f("session %d pid %ld", s->self, (long)s->pid); 1301 if (s->ttyfd != -1) { 1302 debug3_f("tty %s ptyfd %d", s->tty, s->ptyfd); 1303 session_pty_cleanup2(s); 1304 } 1305 session_unused(s->self); 1306} 1307 1308int 1309mm_answer_pty(struct ssh *ssh, int sock, struct sshbuf *m) 1310{ 1311 extern struct monitor *pmonitor; 1312 Session *s; 1313 int r, res, fd0; 1314 1315 debug3_f("entering"); 1316 1317 sshbuf_reset(m); 1318 s = session_new(); 1319 if (s == NULL) 1320 goto error; 1321 s->authctxt = authctxt; 1322 s->pw = authctxt->pw; 1323 s->pid = pmonitor->m_pid; 1324 res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); 1325 if (res == 0) 1326 goto error; 1327 pty_setowner(authctxt->pw, s->tty); 1328 1329 if ((r = sshbuf_put_u32(m, 1)) != 0 || 1330 (r = sshbuf_put_cstring(m, s->tty)) != 0) 1331 fatal_fr(r, "assemble"); 1332 1333 /* We need to trick ttyslot */ 1334 if (dup2(s->ttyfd, 0) == -1) 1335 fatal_f("dup2"); 1336 1337 mm_record_login(ssh, s, authctxt->pw); 1338 1339 /* Now we can close the file descriptor again */ 1340 close(0); 1341 1342 /* send messages generated by record_login */ 1343 if ((r = sshbuf_put_stringb(m, loginmsg)) != 0) 1344 fatal_fr(r, "assemble loginmsg"); 1345 sshbuf_reset(loginmsg); 1346 1347 mm_request_send(sock, MONITOR_ANS_PTY, m); 1348 1349 if (mm_send_fd(sock, s->ptyfd) == -1 || 1350 mm_send_fd(sock, s->ttyfd) == -1) 1351 fatal_f("send fds failed"); 1352 1353 /* make sure nothing uses fd 0 */ 1354 if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1355 fatal_f("open(/dev/null): %s", strerror(errno)); 1356 if (fd0 != 0) 1357 error_f("fd0 %d != 0", fd0); 1358 1359 /* slave side of pty is not needed */ 1360 close(s->ttyfd); 1361 s->ttyfd = s->ptyfd; 1362 /* no need to dup() because nobody closes ptyfd */ 1363 s->ptymaster = s->ptyfd; 1364 1365 debug3_f("tty %s ptyfd %d", s->tty, s->ttyfd); 1366 1367 return (0); 1368 1369 error: 1370 if (s != NULL) 1371 mm_session_close(s); 1372 if ((r = sshbuf_put_u32(m, 0)) != 0) 1373 fatal_fr(r, "assemble 0"); 1374 mm_request_send(sock, MONITOR_ANS_PTY, m); 1375 return (0); 1376} 1377 1378int 1379mm_answer_pty_cleanup(struct ssh *ssh, int sock, struct sshbuf *m) 1380{ 1381 Session *s; 1382 char *tty; 1383 int r; 1384 1385 debug3_f("entering"); 1386 1387 if ((r = sshbuf_get_cstring(m, &tty, NULL)) != 0) 1388 fatal_fr(r, "parse tty"); 1389 if ((s = session_by_tty(tty)) != NULL) 1390 mm_session_close(s); 1391 sshbuf_reset(m); 1392 free(tty); 1393 return (0); 1394} 1395 1396int 1397mm_answer_term(struct ssh *ssh, int sock, struct sshbuf *req) 1398{ 1399 extern struct monitor *pmonitor; 1400 int res, status; 1401 1402 debug3_f("tearing down sessions"); 1403 1404 /* The child is terminating */ 1405 session_destroy_all(ssh, &mm_session_close); 1406 1407 while (waitpid(pmonitor->m_pid, &status, 0) == -1) 1408 if (errno != EINTR) 1409 exit(1); 1410 1411 res = WIFEXITED(status) ? WEXITSTATUS(status) : 1; 1412 1413 /* Terminate process */ 1414 exit(res); 1415} 1416 1417void 1418monitor_clear_keystate(struct ssh *ssh, struct monitor *pmonitor) 1419{ 1420 ssh_clear_newkeys(ssh, MODE_IN); 1421 ssh_clear_newkeys(ssh, MODE_OUT); 1422 sshbuf_free(child_state); 1423 child_state = NULL; 1424} 1425 1426void 1427monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor) 1428{ 1429 struct kex *kex; 1430 int r; 1431 1432 debug3_f("packet_set_state"); 1433 if ((r = ssh_packet_set_state(ssh, child_state)) != 0) 1434 fatal_fr(r, "packet_set_state"); 1435 sshbuf_free(child_state); 1436 child_state = NULL; 1437 if ((kex = ssh->kex) == NULL) 1438 fatal_f("internal error: ssh->kex == NULL"); 1439 if (session_id2_len != sshbuf_len(ssh->kex->session_id)) { 1440 fatal_f("incorrect session id length %zu (expected %u)", 1441 sshbuf_len(ssh->kex->session_id), session_id2_len); 1442 } 1443 if (memcmp(sshbuf_ptr(ssh->kex->session_id), session_id2, 1444 session_id2_len) != 0) 1445 fatal_f("session ID mismatch"); 1446 /* XXX set callbacks */ 1447#ifdef WITH_OPENSSL 1448 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server; 1449 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server; 1450 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server; 1451 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server; 1452 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server; 1453 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 1454 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 1455 kex->kex[KEX_ECDH_SHA2] = kex_gen_server; 1456#endif 1457 kex->kex[KEX_C25519_SHA256] = kex_gen_server; 1458 kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server; 1459 kex->load_host_public_key=&get_hostkey_public_by_type; 1460 kex->load_host_private_key=&get_hostkey_private_by_type; 1461 kex->host_key_index=&get_hostkey_index; 1462 kex->sign = sshd_hostkey_sign; 1463} 1464 1465/* This function requires careful sanity checking */ 1466 1467void 1468mm_get_keystate(struct ssh *ssh, struct monitor *pmonitor) 1469{ 1470 debug3_f("Waiting for new keys"); 1471 1472 if ((child_state = sshbuf_new()) == NULL) 1473 fatal_f("sshbuf_new failed"); 1474 mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, 1475 child_state); 1476 debug3_f("GOT new keys"); 1477} 1478 1479 1480/* XXX */ 1481 1482#define FD_CLOSEONEXEC(x) do { \ 1483 if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \ 1484 fatal("fcntl(%d, F_SETFD)", x); \ 1485} while (0) 1486 1487static void 1488monitor_openfds(struct monitor *mon, int do_logfds) 1489{ 1490 int pair[2]; 1491#ifdef SO_ZEROIZE 1492 int on = 1; 1493#endif 1494 1495 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) 1496 fatal_f("socketpair: %s", strerror(errno)); 1497#ifdef SO_ZEROIZE 1498 if (setsockopt(pair[0], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1499 error("setsockopt SO_ZEROIZE(0): %.100s", strerror(errno)); 1500 if (setsockopt(pair[1], SOL_SOCKET, SO_ZEROIZE, &on, sizeof(on)) == -1) 1501 error("setsockopt SO_ZEROIZE(1): %.100s", strerror(errno)); 1502#endif 1503 FD_CLOSEONEXEC(pair[0]); 1504 FD_CLOSEONEXEC(pair[1]); 1505 mon->m_recvfd = pair[0]; 1506 mon->m_sendfd = pair[1]; 1507 1508 if (do_logfds) { 1509 if (pipe(pair) == -1) 1510 fatal_f("pipe: %s", strerror(errno)); 1511 FD_CLOSEONEXEC(pair[0]); 1512 FD_CLOSEONEXEC(pair[1]); 1513 mon->m_log_recvfd = pair[0]; 1514 mon->m_log_sendfd = pair[1]; 1515 } else 1516 mon->m_log_recvfd = mon->m_log_sendfd = -1; 1517} 1518 1519#define MM_MEMSIZE 65536 1520 1521struct monitor * 1522monitor_init(void) 1523{ 1524 struct monitor *mon; 1525 1526 mon = xcalloc(1, sizeof(*mon)); 1527 monitor_openfds(mon, 1); 1528 1529 return mon; 1530} 1531 1532void 1533monitor_reinit(struct monitor *mon) 1534{ 1535 monitor_openfds(mon, 0); 1536} 1537 1538#ifdef GSSAPI 1539int 1540mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1541{ 1542 gss_OID_desc goid; 1543 OM_uint32 major; 1544 size_t len; 1545 u_char *p; 1546 int r; 1547 1548 if (!options.gss_authentication) 1549 fatal_f("GSSAPI authentication not enabled"); 1550 1551 if ((r = sshbuf_get_string(m, &p, &len)) != 0) 1552 fatal_fr(r, "parse"); 1553 goid.elements = p; 1554 goid.length = len; 1555 1556 major = ssh_gssapi_server_ctx(&gsscontext, &goid); 1557 1558 free(goid.elements); 1559 1560 sshbuf_reset(m); 1561 if ((r = sshbuf_put_u32(m, major)) != 0) 1562 fatal_fr(r, "assemble"); 1563 1564 mm_request_send(sock, MONITOR_ANS_GSSSETUP, m); 1565 1566 /* Now we have a context, enable the step */ 1567 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1); 1568 1569 return (0); 1570} 1571 1572int 1573mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m) 1574{ 1575 gss_buffer_desc in; 1576 gss_buffer_desc out = GSS_C_EMPTY_BUFFER; 1577 OM_uint32 major, minor; 1578 OM_uint32 flags = 0; /* GSI needs this */ 1579 int r; 1580 1581 if (!options.gss_authentication) 1582 fatal_f("GSSAPI authentication not enabled"); 1583 1584 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0) 1585 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1586 major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); 1587 free(in.value); 1588 1589 sshbuf_reset(m); 1590 if ((r = sshbuf_put_u32(m, major)) != 0 || 1591 (r = sshbuf_put_string(m, out.value, out.length)) != 0 || 1592 (r = sshbuf_put_u32(m, flags)) != 0) 1593 fatal_fr(r, "assemble"); 1594 mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); 1595 1596 gss_release_buffer(&minor, &out); 1597 1598 if (major == GSS_S_COMPLETE) { 1599 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); 1600 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1601 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); 1602 } 1603 return (0); 1604} 1605 1606int 1607mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m) 1608{ 1609 gss_buffer_desc gssbuf, mic; 1610 OM_uint32 ret; 1611 int r; 1612 1613 if (!options.gss_authentication) 1614 fatal_f("GSSAPI authentication not enabled"); 1615 1616 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 || 1617 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0) 1618 fatal_fr(r, "ssh_gssapi_get_buffer_desc"); 1619 1620 ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic); 1621 1622 free(gssbuf.value); 1623 free(mic.value); 1624 1625 sshbuf_reset(m); 1626 if ((r = sshbuf_put_u32(m, ret)) != 0) 1627 fatal_fr(r, "assemble"); 1628 1629 mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m); 1630 1631 if (!GSS_ERROR(ret)) 1632 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); 1633 1634 return (0); 1635} 1636 1637int 1638mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m) 1639{ 1640 int r, authenticated; 1641 const char *displayname; 1642 1643 if (!options.gss_authentication) 1644 fatal_f("GSSAPI authentication not enabled"); 1645 1646 authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); 1647 1648 sshbuf_reset(m); 1649 if ((r = sshbuf_put_u32(m, authenticated)) != 0) 1650 fatal_fr(r, "assemble"); 1651 1652 debug3_f("sending result %d", authenticated); 1653 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m); 1654 1655 auth_method = "gssapi-with-mic"; 1656 1657 if ((displayname = ssh_gssapi_displayname()) != NULL) 1658 auth2_record_info(authctxt, "%s", displayname); 1659 1660 /* Monitor loop will terminate if authenticated */ 1661 return (authenticated); 1662} 1663#endif /* GSSAPI */ 1664 1665