1 /* $OpenBSD: auth-options.c,v 1.92 2020/03/06 18:15:38 markus Exp $ */ 2 /* 3 * Copyright (c) 2018 Damien Miller <djm@mindrot.org> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #include "includes.h" 19 20 #include <sys/types.h> 21 22 #include <stdlib.h> 23 #include <netdb.h> 24 #include <pwd.h> 25 #include <string.h> 26 #include <stdio.h> 27 #include <stdarg.h> 28 #include <ctype.h> 29 #include <limits.h> 30 31 #include "openbsd-compat/sys-queue.h" 32 33 #include "xmalloc.h" 34 #include "ssherr.h" 35 #include "log.h" 36 #include "sshbuf.h" 37 #include "misc.h" 38 #include "sshkey.h" 39 #include "match.h" 40 #include "ssh2.h" 41 #include "auth-options.h" 42 43 static int 44 dup_strings(char ***dstp, size_t *ndstp, char **src, size_t nsrc) 45 { 46 char **dst; 47 size_t i, j; 48 49 *dstp = NULL; 50 *ndstp = 0; 51 if (nsrc == 0) 52 return 0; 53 54 if ((dst = calloc(nsrc, sizeof(*src))) == NULL) 55 return -1; 56 for (i = 0; i < nsrc; i++) { 57 if ((dst[i] = strdup(src[i])) == NULL) { 58 for (j = 0; j < i; j++) 59 free(dst[j]); 60 free(dst); 61 return -1; 62 } 63 } 64 /* success */ 65 *dstp = dst; 66 *ndstp = nsrc; 67 return 0; 68 } 69 70 #define OPTIONS_CRITICAL 1 71 #define OPTIONS_EXTENSIONS 2 72 static int 73 cert_option_list(struct sshauthopt *opts, struct sshbuf *oblob, 74 u_int which, int crit) 75 { 76 char *command, *allowed; 77 char *name = NULL; 78 struct sshbuf *c = NULL, *data = NULL; 79 int r, ret = -1, found; 80 81 if ((c = sshbuf_fromb(oblob)) == NULL) { 82 error("%s: sshbuf_fromb failed", __func__); 83 goto out; 84 } 85 86 while (sshbuf_len(c) > 0) { 87 sshbuf_free(data); 88 data = NULL; 89 if ((r = sshbuf_get_cstring(c, &name, NULL)) != 0 || 90 (r = sshbuf_froms(c, &data)) != 0) { 91 error("Unable to parse certificate options: %s", 92 ssh_err(r)); 93 goto out; 94 } 95 debug3("found certificate option \"%.100s\" len %zu", 96 name, sshbuf_len(data)); 97 found = 0; 98 if ((which & OPTIONS_EXTENSIONS) != 0) { 99 if (strcmp(name, "no-touch-required") == 0) { 100 opts->no_require_user_presence = 1; 101 found = 1; 102 } else if (strcmp(name, "permit-X11-forwarding") == 0) { 103 opts->permit_x11_forwarding_flag = 1; 104 found = 1; 105 } else if (strcmp(name, 106 "permit-agent-forwarding") == 0) { 107 opts->permit_agent_forwarding_flag = 1; 108 found = 1; 109 } else if (strcmp(name, 110 "permit-port-forwarding") == 0) { 111 opts->permit_port_forwarding_flag = 1; 112 found = 1; 113 } else if (strcmp(name, "permit-pty") == 0) { 114 opts->permit_pty_flag = 1; 115 found = 1; 116 } else if (strcmp(name, "permit-user-rc") == 0) { 117 opts->permit_user_rc = 1; 118 found = 1; 119 } 120 } 121 if (!found && (which & OPTIONS_CRITICAL) != 0) { 122 if (strcmp(name, "force-command") == 0) { 123 if ((r = sshbuf_get_cstring(data, &command, 124 NULL)) != 0) { 125 error("Unable to parse \"%s\" " 126 "section: %s", name, ssh_err(r)); 127 goto out; 128 } 129 if (opts->force_command != NULL) { 130 error("Certificate has multiple " 131 "force-command options"); 132 free(command); 133 goto out; 134 } 135 opts->force_command = command; 136 found = 1; 137 } 138 if (strcmp(name, "source-address") == 0) { 139 if ((r = sshbuf_get_cstring(data, &allowed, 140 NULL)) != 0) { 141 error("Unable to parse \"%s\" " 142 "section: %s", name, ssh_err(r)); 143 goto out; 144 } 145 if (opts->required_from_host_cert != NULL) { 146 error("Certificate has multiple " 147 "source-address options"); 148 free(allowed); 149 goto out; 150 } 151 /* Check syntax */ 152 if (addr_match_cidr_list(NULL, allowed) == -1) { 153 error("Certificate source-address " 154 "contents invalid"); 155 goto out; 156 } 157 opts->required_from_host_cert = allowed; 158 found = 1; 159 } 160 } 161 162 if (!found) { 163 if (crit) { 164 error("Certificate critical option \"%s\" " 165 "is not supported", name); 166 goto out; 167 } else { 168 logit("Certificate extension \"%s\" " 169 "is not supported", name); 170 } 171 } else if (sshbuf_len(data) != 0) { 172 error("Certificate option \"%s\" corrupt " 173 "(extra data)", name); 174 goto out; 175 } 176 free(name); 177 name = NULL; 178 } 179 /* successfully parsed all options */ 180 ret = 0; 181 182 out: 183 free(name); 184 sshbuf_free(data); 185 sshbuf_free(c); 186 return ret; 187 } 188 189 struct sshauthopt * 190 sshauthopt_new(void) 191 { 192 struct sshauthopt *ret; 193 194 if ((ret = calloc(1, sizeof(*ret))) == NULL) 195 return NULL; 196 ret->force_tun_device = -1; 197 return ret; 198 } 199 200 void 201 sshauthopt_free(struct sshauthopt *opts) 202 { 203 size_t i; 204 205 if (opts == NULL) 206 return; 207 208 free(opts->cert_principals); 209 free(opts->force_command); 210 free(opts->required_from_host_cert); 211 free(opts->required_from_host_keys); 212 213 for (i = 0; i < opts->nenv; i++) 214 free(opts->env[i]); 215 free(opts->env); 216 217 for (i = 0; i < opts->npermitopen; i++) 218 free(opts->permitopen[i]); 219 free(opts->permitopen); 220 221 for (i = 0; i < opts->npermitlisten; i++) 222 free(opts->permitlisten[i]); 223 free(opts->permitlisten); 224 225 freezero(opts, sizeof(*opts)); 226 } 227 228 struct sshauthopt * 229 sshauthopt_new_with_keys_defaults(void) 230 { 231 struct sshauthopt *ret = NULL; 232 233 if ((ret = sshauthopt_new()) == NULL) 234 return NULL; 235 236 /* Defaults for authorized_keys flags */ 237 ret->permit_port_forwarding_flag = 1; 238 ret->permit_agent_forwarding_flag = 1; 239 ret->permit_x11_forwarding_flag = 1; 240 ret->permit_pty_flag = 1; 241 ret->permit_user_rc = 1; 242 return ret; 243 } 244 245 /* 246 * Parse and record a permitopen/permitlisten directive. 247 * Return 0 on success. Return -1 on failure and sets *errstrp to error reason. 248 */ 249 static int 250 handle_permit(const char **optsp, int allow_bare_port, 251 char ***permitsp, size_t *npermitsp, const char **errstrp) 252 { 253 char *opt, *tmp, *cp, *host, **permits = *permitsp; 254 size_t npermits = *npermitsp; 255 const char *errstr = "unknown error"; 256 257 if (npermits > SSH_AUTHOPT_PERMIT_MAX) { 258 *errstrp = "too many permission directives"; 259 return -1; 260 } 261 if ((opt = opt_dequote(optsp, &errstr)) == NULL) { 262 return -1; 263 } 264 if (allow_bare_port && strchr(opt, ':') == NULL) { 265 /* 266 * Allow a bare port number in permitlisten to indicate a 267 * listen_host wildcard. 268 */ 269 if (asprintf(&tmp, "*:%s", opt) == -1) { 270 free(opt); 271 *errstrp = "memory allocation failed"; 272 return -1; 273 } 274 free(opt); 275 opt = tmp; 276 } 277 if ((tmp = strdup(opt)) == NULL) { 278 free(opt); 279 *errstrp = "memory allocation failed"; 280 return -1; 281 } 282 cp = tmp; 283 /* validate syntax before recording it. */ 284 host = hpdelim(&cp); 285 if (host == NULL || strlen(host) >= NI_MAXHOST) { 286 free(tmp); 287 free(opt); 288 *errstrp = "invalid permission hostname"; 289 return -1; 290 } 291 /* 292 * don't want to use permitopen_port to avoid 293 * dependency on channels.[ch] here. 294 */ 295 if (cp == NULL || 296 (strcmp(cp, "*") != 0 && a2port(cp) <= 0)) { 297 free(tmp); 298 free(opt); 299 *errstrp = "invalid permission port"; 300 return -1; 301 } 302 /* XXX - add streamlocal support */ 303 free(tmp); 304 /* Record it */ 305 if ((permits = recallocarray(permits, npermits, npermits + 1, 306 sizeof(*permits))) == NULL) { 307 free(opt); 308 /* NB. don't update *permitsp if alloc fails */ 309 *errstrp = "memory allocation failed"; 310 return -1; 311 } 312 permits[npermits++] = opt; 313 *permitsp = permits; 314 *npermitsp = npermits; 315 return 0; 316 } 317 318 struct sshauthopt * 319 sshauthopt_parse(const char *opts, const char **errstrp) 320 { 321 char **oarray, *opt, *cp, *tmp; 322 int r; 323 struct sshauthopt *ret = NULL; 324 const char *errstr = "unknown error"; 325 uint64_t valid_before; 326 327 if (errstrp != NULL) 328 *errstrp = NULL; 329 if ((ret = sshauthopt_new_with_keys_defaults()) == NULL) 330 goto alloc_fail; 331 332 if (opts == NULL) 333 return ret; 334 335 while (*opts && *opts != ' ' && *opts != '\t') { 336 /* flag options */ 337 if ((r = opt_flag("restrict", 0, &opts)) != -1) { 338 ret->restricted = 1; 339 ret->permit_port_forwarding_flag = 0; 340 ret->permit_agent_forwarding_flag = 0; 341 ret->permit_x11_forwarding_flag = 0; 342 ret->permit_pty_flag = 0; 343 ret->permit_user_rc = 0; 344 } else if ((r = opt_flag("cert-authority", 0, &opts)) != -1) { 345 ret->cert_authority = r; 346 } else if ((r = opt_flag("port-forwarding", 1, &opts)) != -1) { 347 ret->permit_port_forwarding_flag = r == 1; 348 } else if ((r = opt_flag("agent-forwarding", 1, &opts)) != -1) { 349 ret->permit_agent_forwarding_flag = r == 1; 350 } else if ((r = opt_flag("x11-forwarding", 1, &opts)) != -1) { 351 ret->permit_x11_forwarding_flag = r == 1; 352 } else if ((r = opt_flag("touch-required", 1, &opts)) != -1) { 353 ret->no_require_user_presence = r != 1; /* NB. flip */ 354 } else if ((r = opt_flag("pty", 1, &opts)) != -1) { 355 ret->permit_pty_flag = r == 1; 356 } else if ((r = opt_flag("user-rc", 1, &opts)) != -1) { 357 ret->permit_user_rc = r == 1; 358 } else if (opt_match(&opts, "command")) { 359 if (ret->force_command != NULL) { 360 errstr = "multiple \"command\" clauses"; 361 goto fail; 362 } 363 ret->force_command = opt_dequote(&opts, &errstr); 364 if (ret->force_command == NULL) 365 goto fail; 366 } else if (opt_match(&opts, "principals")) { 367 if (ret->cert_principals != NULL) { 368 errstr = "multiple \"principals\" clauses"; 369 goto fail; 370 } 371 ret->cert_principals = opt_dequote(&opts, &errstr); 372 if (ret->cert_principals == NULL) 373 goto fail; 374 } else if (opt_match(&opts, "from")) { 375 if (ret->required_from_host_keys != NULL) { 376 errstr = "multiple \"from\" clauses"; 377 goto fail; 378 } 379 ret->required_from_host_keys = opt_dequote(&opts, 380 &errstr); 381 if (ret->required_from_host_keys == NULL) 382 goto fail; 383 } else if (opt_match(&opts, "expiry-time")) { 384 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 385 goto fail; 386 if (parse_absolute_time(opt, &valid_before) != 0 || 387 valid_before == 0) { 388 free(opt); 389 errstr = "invalid expires time"; 390 goto fail; 391 } 392 free(opt); 393 if (ret->valid_before == 0 || 394 valid_before < ret->valid_before) 395 ret->valid_before = valid_before; 396 } else if (opt_match(&opts, "environment")) { 397 if (ret->nenv > INT_MAX) { 398 errstr = "too many environment strings"; 399 goto fail; 400 } 401 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 402 goto fail; 403 /* env name must be alphanumeric and followed by '=' */ 404 if ((tmp = strchr(opt, '=')) == NULL) { 405 free(opt); 406 errstr = "invalid environment string"; 407 goto fail; 408 } 409 if ((cp = strdup(opt)) == NULL) 410 goto alloc_fail; 411 cp[tmp - opt] = '\0'; /* truncate at '=' */ 412 if (!valid_env_name(cp)) { 413 free(cp); 414 free(opt); 415 errstr = "invalid environment string"; 416 goto fail; 417 } 418 free(cp); 419 /* Append it. */ 420 oarray = ret->env; 421 if ((ret->env = recallocarray(ret->env, ret->nenv, 422 ret->nenv + 1, sizeof(*ret->env))) == NULL) { 423 free(opt); 424 ret->env = oarray; /* put it back for cleanup */ 425 goto alloc_fail; 426 } 427 ret->env[ret->nenv++] = opt; 428 } else if (opt_match(&opts, "permitopen")) { 429 if (handle_permit(&opts, 0, &ret->permitopen, 430 &ret->npermitopen, &errstr) != 0) 431 goto fail; 432 } else if (opt_match(&opts, "permitlisten")) { 433 if (handle_permit(&opts, 1, &ret->permitlisten, 434 &ret->npermitlisten, &errstr) != 0) 435 goto fail; 436 } else if (opt_match(&opts, "tunnel")) { 437 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 438 goto fail; 439 ret->force_tun_device = a2tun(opt, NULL); 440 free(opt); 441 if (ret->force_tun_device == SSH_TUNID_ERR) { 442 errstr = "invalid tun device"; 443 goto fail; 444 } 445 } 446 /* 447 * Skip the comma, and move to the next option 448 * (or break out if there are no more). 449 */ 450 if (*opts == '\0' || *opts == ' ' || *opts == '\t') 451 break; /* End of options. */ 452 /* Anything other than a comma is an unknown option */ 453 if (*opts != ',') { 454 errstr = "unknown key option"; 455 goto fail; 456 } 457 opts++; 458 if (*opts == '\0') { 459 errstr = "unexpected end-of-options"; 460 goto fail; 461 } 462 } 463 464 /* success */ 465 if (errstrp != NULL) 466 *errstrp = NULL; 467 return ret; 468 469 alloc_fail: 470 errstr = "memory allocation failed"; 471 fail: 472 sshauthopt_free(ret); 473 if (errstrp != NULL) 474 *errstrp = errstr; 475 return NULL; 476 } 477 478 struct sshauthopt * 479 sshauthopt_from_cert(struct sshkey *k) 480 { 481 struct sshauthopt *ret; 482 483 if (k == NULL || !sshkey_type_is_cert(k->type) || k->cert == NULL || 484 k->cert->type != SSH2_CERT_TYPE_USER) 485 return NULL; 486 487 if ((ret = sshauthopt_new()) == NULL) 488 return NULL; 489 490 /* Handle options and critical extensions separately */ 491 if (cert_option_list(ret, k->cert->critical, 492 OPTIONS_CRITICAL, 1) == -1) { 493 sshauthopt_free(ret); 494 return NULL; 495 } 496 if (cert_option_list(ret, k->cert->extensions, 497 OPTIONS_EXTENSIONS, 0) == -1) { 498 sshauthopt_free(ret); 499 return NULL; 500 } 501 /* success */ 502 return ret; 503 } 504 505 /* 506 * Merges "additional" options to "primary" and returns the result. 507 * NB. Some options from primary have primacy. 508 */ 509 struct sshauthopt * 510 sshauthopt_merge(const struct sshauthopt *primary, 511 const struct sshauthopt *additional, const char **errstrp) 512 { 513 struct sshauthopt *ret; 514 const char *errstr = "internal error"; 515 const char *tmp; 516 517 if (errstrp != NULL) 518 *errstrp = NULL; 519 520 if ((ret = sshauthopt_new()) == NULL) 521 goto alloc_fail; 522 523 /* cert_authority and cert_principals are cleared in result */ 524 525 /* Prefer access lists from primary. */ 526 /* XXX err is both set and mismatch? */ 527 tmp = primary->required_from_host_cert; 528 if (tmp == NULL) 529 tmp = additional->required_from_host_cert; 530 if (tmp != NULL && (ret->required_from_host_cert = strdup(tmp)) == NULL) 531 goto alloc_fail; 532 tmp = primary->required_from_host_keys; 533 if (tmp == NULL) 534 tmp = additional->required_from_host_keys; 535 if (tmp != NULL && (ret->required_from_host_keys = strdup(tmp)) == NULL) 536 goto alloc_fail; 537 538 /* 539 * force_tun_device, permitopen/permitlisten and environment all 540 * prefer the primary. 541 */ 542 ret->force_tun_device = primary->force_tun_device; 543 if (ret->force_tun_device == -1) 544 ret->force_tun_device = additional->force_tun_device; 545 if (primary->nenv > 0) { 546 if (dup_strings(&ret->env, &ret->nenv, 547 primary->env, primary->nenv) != 0) 548 goto alloc_fail; 549 } else if (additional->nenv) { 550 if (dup_strings(&ret->env, &ret->nenv, 551 additional->env, additional->nenv) != 0) 552 goto alloc_fail; 553 } 554 if (primary->npermitopen > 0) { 555 if (dup_strings(&ret->permitopen, &ret->npermitopen, 556 primary->permitopen, primary->npermitopen) != 0) 557 goto alloc_fail; 558 } else if (additional->npermitopen > 0) { 559 if (dup_strings(&ret->permitopen, &ret->npermitopen, 560 additional->permitopen, additional->npermitopen) != 0) 561 goto alloc_fail; 562 } 563 564 if (primary->npermitlisten > 0) { 565 if (dup_strings(&ret->permitlisten, &ret->npermitlisten, 566 primary->permitlisten, primary->npermitlisten) != 0) 567 goto alloc_fail; 568 } else if (additional->npermitlisten > 0) { 569 if (dup_strings(&ret->permitlisten, &ret->npermitlisten, 570 additional->permitlisten, additional->npermitlisten) != 0) 571 goto alloc_fail; 572 } 573 574 #define OPTFLAG_AND(x) ret->x = (primary->x == 1) && (additional->x == 1) 575 /* Permissive flags are logical-AND (i.e. must be set in both) */ 576 OPTFLAG_AND(permit_port_forwarding_flag); 577 OPTFLAG_AND(permit_agent_forwarding_flag); 578 OPTFLAG_AND(permit_x11_forwarding_flag); 579 OPTFLAG_AND(permit_pty_flag); 580 OPTFLAG_AND(permit_user_rc); 581 OPTFLAG_AND(no_require_user_presence); 582 #undef OPTFLAG_AND 583 584 /* Earliest expiry time should win */ 585 if (primary->valid_before != 0) 586 ret->valid_before = primary->valid_before; 587 if (additional->valid_before != 0 && 588 additional->valid_before < ret->valid_before) 589 ret->valid_before = additional->valid_before; 590 591 /* 592 * When both multiple forced-command are specified, only 593 * proceed if they are identical, otherwise fail. 594 */ 595 if (primary->force_command != NULL && 596 additional->force_command != NULL) { 597 if (strcmp(primary->force_command, 598 additional->force_command) == 0) { 599 /* ok */ 600 ret->force_command = strdup(primary->force_command); 601 if (ret->force_command == NULL) 602 goto alloc_fail; 603 } else { 604 errstr = "forced command options do not match"; 605 goto fail; 606 } 607 } else if (primary->force_command != NULL) { 608 if ((ret->force_command = strdup( 609 primary->force_command)) == NULL) 610 goto alloc_fail; 611 } else if (additional->force_command != NULL) { 612 if ((ret->force_command = strdup( 613 additional->force_command)) == NULL) 614 goto alloc_fail; 615 } 616 /* success */ 617 if (errstrp != NULL) 618 *errstrp = NULL; 619 return ret; 620 621 alloc_fail: 622 errstr = "memory allocation failed"; 623 fail: 624 if (errstrp != NULL) 625 *errstrp = errstr; 626 sshauthopt_free(ret); 627 return NULL; 628 } 629 630 /* 631 * Copy options 632 */ 633 struct sshauthopt * 634 sshauthopt_copy(const struct sshauthopt *orig) 635 { 636 struct sshauthopt *ret; 637 638 if ((ret = sshauthopt_new()) == NULL) 639 return NULL; 640 641 #define OPTSCALAR(x) ret->x = orig->x 642 OPTSCALAR(permit_port_forwarding_flag); 643 OPTSCALAR(permit_agent_forwarding_flag); 644 OPTSCALAR(permit_x11_forwarding_flag); 645 OPTSCALAR(permit_pty_flag); 646 OPTSCALAR(permit_user_rc); 647 OPTSCALAR(restricted); 648 OPTSCALAR(cert_authority); 649 OPTSCALAR(force_tun_device); 650 OPTSCALAR(valid_before); 651 OPTSCALAR(no_require_user_presence); 652 #undef OPTSCALAR 653 #define OPTSTRING(x) \ 654 do { \ 655 if (orig->x != NULL && (ret->x = strdup(orig->x)) == NULL) { \ 656 sshauthopt_free(ret); \ 657 return NULL; \ 658 } \ 659 } while (0) 660 OPTSTRING(cert_principals); 661 OPTSTRING(force_command); 662 OPTSTRING(required_from_host_cert); 663 OPTSTRING(required_from_host_keys); 664 #undef OPTSTRING 665 666 if (dup_strings(&ret->env, &ret->nenv, orig->env, orig->nenv) != 0 || 667 dup_strings(&ret->permitopen, &ret->npermitopen, 668 orig->permitopen, orig->npermitopen) != 0 || 669 dup_strings(&ret->permitlisten, &ret->npermitlisten, 670 orig->permitlisten, orig->npermitlisten) != 0) { 671 sshauthopt_free(ret); 672 return NULL; 673 } 674 return ret; 675 } 676 677 static int 678 serialise_array(struct sshbuf *m, char **a, size_t n) 679 { 680 struct sshbuf *b; 681 size_t i; 682 int r; 683 684 if (n > INT_MAX) 685 return SSH_ERR_INTERNAL_ERROR; 686 687 if ((b = sshbuf_new()) == NULL) { 688 return SSH_ERR_ALLOC_FAIL; 689 } 690 for (i = 0; i < n; i++) { 691 if ((r = sshbuf_put_cstring(b, a[i])) != 0) { 692 sshbuf_free(b); 693 return r; 694 } 695 } 696 if ((r = sshbuf_put_u32(m, n)) != 0 || 697 (r = sshbuf_put_stringb(m, b)) != 0) { 698 sshbuf_free(b); 699 return r; 700 } 701 /* success */ 702 return 0; 703 } 704 705 static int 706 deserialise_array(struct sshbuf *m, char ***ap, size_t *np) 707 { 708 char **a = NULL; 709 size_t i, n = 0; 710 struct sshbuf *b = NULL; 711 u_int tmp; 712 int r = SSH_ERR_INTERNAL_ERROR; 713 714 if ((r = sshbuf_get_u32(m, &tmp)) != 0 || 715 (r = sshbuf_froms(m, &b)) != 0) 716 goto out; 717 if (tmp > INT_MAX) { 718 r = SSH_ERR_INVALID_FORMAT; 719 goto out; 720 } 721 n = tmp; 722 if (n > 0 && (a = calloc(n, sizeof(*a))) == NULL) { 723 r = SSH_ERR_ALLOC_FAIL; 724 goto out; 725 } 726 for (i = 0; i < n; i++) { 727 if ((r = sshbuf_get_cstring(b, &a[i], NULL)) != 0) 728 goto out; 729 } 730 /* success */ 731 r = 0; 732 *ap = a; 733 a = NULL; 734 *np = n; 735 n = 0; 736 out: 737 if (a != NULL) { 738 for (i = 0; i < n; i++) 739 free(a[i]); 740 free(a); 741 } 742 sshbuf_free(b); 743 return r; 744 } 745 746 static int 747 serialise_nullable_string(struct sshbuf *m, const char *s) 748 { 749 int r; 750 751 if ((r = sshbuf_put_u8(m, s == NULL)) != 0 || 752 (r = sshbuf_put_cstring(m, s)) != 0) 753 return r; 754 return 0; 755 } 756 757 static int 758 deserialise_nullable_string(struct sshbuf *m, char **sp) 759 { 760 int r; 761 u_char flag; 762 763 *sp = NULL; 764 if ((r = sshbuf_get_u8(m, &flag)) != 0 || 765 (r = sshbuf_get_cstring(m, flag ? NULL : sp, NULL)) != 0) 766 return r; 767 return 0; 768 } 769 770 int 771 sshauthopt_serialise(const struct sshauthopt *opts, struct sshbuf *m, 772 int untrusted) 773 { 774 int r = SSH_ERR_INTERNAL_ERROR; 775 776 /* Flag options */ 777 if ((r = sshbuf_put_u8(m, opts->permit_port_forwarding_flag)) != 0 || 778 (r = sshbuf_put_u8(m, opts->permit_agent_forwarding_flag)) != 0 || 779 (r = sshbuf_put_u8(m, opts->permit_x11_forwarding_flag)) != 0 || 780 (r = sshbuf_put_u8(m, opts->permit_pty_flag)) != 0 || 781 (r = sshbuf_put_u8(m, opts->permit_user_rc)) != 0 || 782 (r = sshbuf_put_u8(m, opts->restricted)) != 0 || 783 (r = sshbuf_put_u8(m, opts->cert_authority)) != 0 || 784 (r = sshbuf_put_u8(m, opts->no_require_user_presence)) != 0) 785 return r; 786 787 /* Simple integer options */ 788 if ((r = sshbuf_put_u64(m, opts->valid_before)) != 0) 789 return r; 790 791 /* tunnel number can be negative to indicate "unset" */ 792 if ((r = sshbuf_put_u8(m, opts->force_tun_device == -1)) != 0 || 793 (r = sshbuf_put_u32(m, (opts->force_tun_device < 0) ? 794 0 : (u_int)opts->force_tun_device)) != 0) 795 return r; 796 797 /* String options; these may be NULL */ 798 if ((r = serialise_nullable_string(m, 799 untrusted ? "yes" : opts->cert_principals)) != 0 || 800 (r = serialise_nullable_string(m, 801 untrusted ? "true" : opts->force_command)) != 0 || 802 (r = serialise_nullable_string(m, 803 untrusted ? NULL : opts->required_from_host_cert)) != 0 || 804 (r = serialise_nullable_string(m, 805 untrusted ? NULL : opts->required_from_host_keys)) != 0) 806 return r; 807 808 /* Array options */ 809 if ((r = serialise_array(m, opts->env, 810 untrusted ? 0 : opts->nenv)) != 0 || 811 (r = serialise_array(m, opts->permitopen, 812 untrusted ? 0 : opts->npermitopen)) != 0 || 813 (r = serialise_array(m, opts->permitlisten, 814 untrusted ? 0 : opts->npermitlisten)) != 0) 815 return r; 816 817 /* success */ 818 return 0; 819 } 820 821 int 822 sshauthopt_deserialise(struct sshbuf *m, struct sshauthopt **optsp) 823 { 824 struct sshauthopt *opts = NULL; 825 int r = SSH_ERR_INTERNAL_ERROR; 826 u_char f; 827 u_int tmp; 828 829 if ((opts = calloc(1, sizeof(*opts))) == NULL) 830 return SSH_ERR_ALLOC_FAIL; 831 832 /* Flag options */ 833 #define OPT_FLAG(x) \ 834 do { \ 835 if ((r = sshbuf_get_u8(m, &f)) != 0) \ 836 goto out; \ 837 opts->x = f; \ 838 } while (0) 839 OPT_FLAG(permit_port_forwarding_flag); 840 OPT_FLAG(permit_agent_forwarding_flag); 841 OPT_FLAG(permit_x11_forwarding_flag); 842 OPT_FLAG(permit_pty_flag); 843 OPT_FLAG(permit_user_rc); 844 OPT_FLAG(restricted); 845 OPT_FLAG(cert_authority); 846 OPT_FLAG(no_require_user_presence); 847 #undef OPT_FLAG 848 849 /* Simple integer options */ 850 if ((r = sshbuf_get_u64(m, &opts->valid_before)) != 0) 851 goto out; 852 853 /* tunnel number can be negative to indicate "unset" */ 854 if ((r = sshbuf_get_u8(m, &f)) != 0 || 855 (r = sshbuf_get_u32(m, &tmp)) != 0) 856 goto out; 857 opts->force_tun_device = f ? -1 : (int)tmp; 858 859 /* String options may be NULL */ 860 if ((r = deserialise_nullable_string(m, &opts->cert_principals)) != 0 || 861 (r = deserialise_nullable_string(m, &opts->force_command)) != 0 || 862 (r = deserialise_nullable_string(m, 863 &opts->required_from_host_cert)) != 0 || 864 (r = deserialise_nullable_string(m, 865 &opts->required_from_host_keys)) != 0) 866 goto out; 867 868 /* Array options */ 869 if ((r = deserialise_array(m, &opts->env, &opts->nenv)) != 0 || 870 (r = deserialise_array(m, 871 &opts->permitopen, &opts->npermitopen)) != 0 || 872 (r = deserialise_array(m, 873 &opts->permitlisten, &opts->npermitlisten)) != 0) 874 goto out; 875 876 /* success */ 877 r = 0; 878 *optsp = opts; 879 opts = NULL; 880 out: 881 sshauthopt_free(opts); 882 return r; 883 } 884