1 /* $OpenBSD: auth-options.c,v 1.78 2018/03/14 05:35:40 djm 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 <netdb.h> 23 #include <pwd.h> 24 #include <string.h> 25 #include <stdio.h> 26 #include <stdarg.h> 27 #include <ctype.h> 28 #include <limits.h> 29 30 #include "openbsd-compat/sys-queue.h" 31 32 #include "xmalloc.h" 33 #include "ssherr.h" 34 #include "log.h" 35 #include "sshbuf.h" 36 #include "misc.h" 37 #include "sshkey.h" 38 #include "match.h" 39 #include "ssh2.h" 40 #include "auth-options.h" 41 42 /* 43 * Match flag 'opt' in *optsp, and if allow_negate is set then also match 44 * 'no-opt'. Returns -1 if option not matched, 1 if option matches or 0 45 * if negated option matches. 46 * If the option or negated option matches, then *optsp is updated to 47 * point to the first character after the option. 48 */ 49 static int 50 opt_flag(const char *opt, int allow_negate, const char **optsp) 51 { 52 size_t opt_len = strlen(opt); 53 const char *opts = *optsp; 54 int negate = 0; 55 56 if (allow_negate && strncasecmp(opts, "no-", 3) == 0) { 57 opts += 3; 58 negate = 1; 59 } 60 if (strncasecmp(opts, opt, opt_len) == 0) { 61 *optsp = opts + opt_len; 62 return negate ? 0 : 1; 63 } 64 return -1; 65 } 66 67 static char * 68 opt_dequote(const char **sp, const char **errstrp) 69 { 70 const char *s = *sp; 71 char *ret; 72 size_t i; 73 74 *errstrp = NULL; 75 if (*s != '"') { 76 *errstrp = "missing start quote"; 77 return NULL; 78 } 79 s++; 80 if ((ret = malloc(strlen((s)) + 1)) == NULL) { 81 *errstrp = "memory allocation failed"; 82 return NULL; 83 } 84 for (i = 0; *s != '\0' && *s != '"';) { 85 if (s[0] == '\\' && s[1] == '"') 86 s++; 87 ret[i++] = *s++; 88 } 89 if (*s == '\0') { 90 *errstrp = "missing end quote"; 91 free(ret); 92 return NULL; 93 } 94 ret[i] = '\0'; 95 s++; 96 *sp = s; 97 return ret; 98 } 99 100 static int 101 opt_match(const char **opts, const char *term) 102 { 103 if (strncasecmp((*opts), term, strlen(term)) == 0 && 104 (*opts)[strlen(term)] == '=') { 105 *opts += strlen(term) + 1; 106 return 1; 107 } 108 return 0; 109 } 110 111 static int 112 dup_strings(char ***dstp, size_t *ndstp, char **src, size_t nsrc) 113 { 114 char **dst; 115 size_t i, j; 116 117 *dstp = NULL; 118 *ndstp = 0; 119 if (nsrc == 0) 120 return 0; 121 122 if ((dst = calloc(nsrc, sizeof(*src))) == NULL) 123 return -1; 124 for (i = 0; i < nsrc; i++) { 125 if ((dst[i] = strdup(src[i])) == NULL) { 126 for (j = 0; j < i; j++) 127 free(dst[j]); 128 free(dst); 129 return -1; 130 } 131 } 132 /* success */ 133 *dstp = dst; 134 *ndstp = nsrc; 135 return 0; 136 } 137 138 #define OPTIONS_CRITICAL 1 139 #define OPTIONS_EXTENSIONS 2 140 static int 141 cert_option_list(struct sshauthopt *opts, struct sshbuf *oblob, 142 u_int which, int crit) 143 { 144 char *command, *allowed; 145 char *name = NULL; 146 struct sshbuf *c = NULL, *data = NULL; 147 int r, ret = -1, found; 148 149 if ((c = sshbuf_fromb(oblob)) == NULL) { 150 error("%s: sshbuf_fromb failed", __func__); 151 goto out; 152 } 153 154 while (sshbuf_len(c) > 0) { 155 sshbuf_free(data); 156 data = NULL; 157 if ((r = sshbuf_get_cstring(c, &name, NULL)) != 0 || 158 (r = sshbuf_froms(c, &data)) != 0) { 159 error("Unable to parse certificate options: %s", 160 ssh_err(r)); 161 goto out; 162 } 163 debug3("found certificate option \"%.100s\" len %zu", 164 name, sshbuf_len(data)); 165 found = 0; 166 if ((which & OPTIONS_EXTENSIONS) != 0) { 167 if (strcmp(name, "permit-X11-forwarding") == 0) { 168 opts->permit_x11_forwarding_flag = 1; 169 found = 1; 170 } else if (strcmp(name, 171 "permit-agent-forwarding") == 0) { 172 opts->permit_agent_forwarding_flag = 1; 173 found = 1; 174 } else if (strcmp(name, 175 "permit-port-forwarding") == 0) { 176 opts->permit_port_forwarding_flag = 1; 177 found = 1; 178 } else if (strcmp(name, "permit-pty") == 0) { 179 opts->permit_pty_flag = 1; 180 found = 1; 181 } else if (strcmp(name, "permit-user-rc") == 0) { 182 opts->permit_user_rc = 1; 183 found = 1; 184 } 185 } 186 if (!found && (which & OPTIONS_CRITICAL) != 0) { 187 if (strcmp(name, "force-command") == 0) { 188 if ((r = sshbuf_get_cstring(data, &command, 189 NULL)) != 0) { 190 error("Unable to parse \"%s\" " 191 "section: %s", name, ssh_err(r)); 192 goto out; 193 } 194 if (opts->force_command != NULL) { 195 error("Certificate has multiple " 196 "force-command options"); 197 free(command); 198 goto out; 199 } 200 opts->force_command = command; 201 found = 1; 202 } 203 if (strcmp(name, "source-address") == 0) { 204 if ((r = sshbuf_get_cstring(data, &allowed, 205 NULL)) != 0) { 206 error("Unable to parse \"%s\" " 207 "section: %s", name, ssh_err(r)); 208 goto out; 209 } 210 if (opts->required_from_host_cert != NULL) { 211 error("Certificate has multiple " 212 "source-address options"); 213 free(allowed); 214 goto out; 215 } 216 /* Check syntax */ 217 if (addr_match_cidr_list(NULL, allowed) == -1) { 218 error("Certificate source-address " 219 "contents invalid"); 220 goto out; 221 } 222 opts->required_from_host_cert = allowed; 223 found = 1; 224 } 225 } 226 227 if (!found) { 228 if (crit) { 229 error("Certificate critical option \"%s\" " 230 "is not supported", name); 231 goto out; 232 } else { 233 logit("Certificate extension \"%s\" " 234 "is not supported", name); 235 } 236 } else if (sshbuf_len(data) != 0) { 237 error("Certificate option \"%s\" corrupt " 238 "(extra data)", name); 239 goto out; 240 } 241 free(name); 242 name = NULL; 243 } 244 /* successfully parsed all options */ 245 ret = 0; 246 247 out: 248 free(name); 249 sshbuf_free(data); 250 sshbuf_free(c); 251 return ret; 252 } 253 254 struct sshauthopt * 255 sshauthopt_new(void) 256 { 257 struct sshauthopt *ret; 258 259 if ((ret = calloc(1, sizeof(*ret))) == NULL) 260 return NULL; 261 ret->force_tun_device = -1; 262 return ret; 263 } 264 265 void 266 sshauthopt_free(struct sshauthopt *opts) 267 { 268 size_t i; 269 270 if (opts == NULL) 271 return; 272 273 free(opts->cert_principals); 274 free(opts->force_command); 275 free(opts->required_from_host_cert); 276 free(opts->required_from_host_keys); 277 278 for (i = 0; i < opts->nenv; i++) 279 free(opts->env[i]); 280 free(opts->env); 281 282 for (i = 0; i < opts->npermitopen; i++) 283 free(opts->permitopen[i]); 284 free(opts->permitopen); 285 286 explicit_bzero(opts, sizeof(*opts)); 287 free(opts); 288 } 289 290 struct sshauthopt * 291 sshauthopt_new_with_keys_defaults(void) 292 { 293 struct sshauthopt *ret = NULL; 294 295 if ((ret = sshauthopt_new()) == NULL) 296 return NULL; 297 298 /* Defaults for authorized_keys flags */ 299 ret->permit_port_forwarding_flag = 1; 300 ret->permit_agent_forwarding_flag = 1; 301 ret->permit_x11_forwarding_flag = 1; 302 ret->permit_pty_flag = 1; 303 ret->permit_user_rc = 1; 304 return ret; 305 } 306 307 struct sshauthopt * 308 sshauthopt_parse(const char *opts, const char **errstrp) 309 { 310 char **oarray, *opt, *cp, *tmp, *host; 311 int r; 312 struct sshauthopt *ret = NULL; 313 const char *errstr = "unknown error"; 314 uint64_t valid_before; 315 316 if (errstrp != NULL) 317 *errstrp = NULL; 318 if ((ret = sshauthopt_new_with_keys_defaults()) == NULL) 319 goto alloc_fail; 320 321 if (opts == NULL) 322 return ret; 323 324 while (*opts && *opts != ' ' && *opts != '\t') { 325 /* flag options */ 326 if ((r = opt_flag("restrict", 0, &opts)) != -1) { 327 ret->restricted = 1; 328 ret->permit_port_forwarding_flag = 0; 329 ret->permit_agent_forwarding_flag = 0; 330 ret->permit_x11_forwarding_flag = 0; 331 ret->permit_pty_flag = 0; 332 ret->permit_user_rc = 0; 333 } else if ((r = opt_flag("cert-authority", 0, &opts)) != -1) { 334 ret->cert_authority = r; 335 } else if ((r = opt_flag("port-forwarding", 1, &opts)) != -1) { 336 ret->permit_port_forwarding_flag = r == 1; 337 } else if ((r = opt_flag("agent-forwarding", 1, &opts)) != -1) { 338 ret->permit_agent_forwarding_flag = r == 1; 339 } else if ((r = opt_flag("x11-forwarding", 1, &opts)) != -1) { 340 ret->permit_x11_forwarding_flag = r == 1; 341 } else if ((r = opt_flag("pty", 1, &opts)) != -1) { 342 ret->permit_pty_flag = r == 1; 343 } else if ((r = opt_flag("user-rc", 1, &opts)) != -1) { 344 ret->permit_user_rc = r == 1; 345 } else if (opt_match(&opts, "command")) { 346 if (ret->force_command != NULL) { 347 errstr = "multiple \"command\" clauses"; 348 goto fail; 349 } 350 ret->force_command = opt_dequote(&opts, &errstr); 351 if (ret->force_command == NULL) 352 goto fail; 353 } else if (opt_match(&opts, "principals")) { 354 if (ret->cert_principals != NULL) { 355 errstr = "multiple \"principals\" clauses"; 356 goto fail; 357 } 358 ret->cert_principals = opt_dequote(&opts, &errstr); 359 if (ret->cert_principals == NULL) 360 goto fail; 361 } else if (opt_match(&opts, "from")) { 362 if (ret->required_from_host_keys != NULL) { 363 errstr = "multiple \"from\" clauses"; 364 goto fail; 365 } 366 ret->required_from_host_keys = opt_dequote(&opts, 367 &errstr); 368 if (ret->required_from_host_keys == NULL) 369 goto fail; 370 } else if (opt_match(&opts, "expiry-time")) { 371 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 372 goto fail; 373 if (parse_absolute_time(opt, &valid_before) != 0 || 374 valid_before == 0) { 375 free(opt); 376 errstr = "invalid expires time"; 377 goto fail; 378 } 379 free(opt); 380 if (ret->valid_before == 0 || 381 valid_before < ret->valid_before) 382 ret->valid_before = valid_before; 383 } else if (opt_match(&opts, "environment")) { 384 if (ret->nenv > INT_MAX) { 385 errstr = "too many environment strings"; 386 goto fail; 387 } 388 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 389 goto fail; 390 /* env name must be alphanumeric and followed by '=' */ 391 if ((tmp = strchr(opt, '=')) == NULL) { 392 free(opt); 393 errstr = "invalid environment string"; 394 goto fail; 395 } 396 for (cp = opt; cp < tmp; cp++) { 397 if (!isalnum((u_char)*cp)) { 398 free(opt); 399 errstr = "invalid environment string"; 400 goto fail; 401 } 402 } 403 /* Append it. */ 404 oarray = ret->env; 405 if ((ret->env = recallocarray(ret->env, ret->nenv, 406 ret->nenv + 1, sizeof(*ret->env))) == NULL) { 407 free(opt); 408 ret->env = oarray; /* put it back for cleanup */ 409 goto alloc_fail; 410 } 411 ret->env[ret->nenv++] = opt; 412 } else if (opt_match(&opts, "permitopen")) { 413 if (ret->npermitopen > INT_MAX) { 414 errstr = "too many permitopens"; 415 goto fail; 416 } 417 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 418 goto fail; 419 if ((tmp = strdup(opt)) == NULL) { 420 free(opt); 421 goto alloc_fail; 422 } 423 cp = tmp; 424 /* validate syntax of permitopen before recording it. */ 425 host = hpdelim(&cp); 426 if (host == NULL || strlen(host) >= NI_MAXHOST) { 427 free(tmp); 428 free(opt); 429 errstr = "invalid permitopen hostname"; 430 goto fail; 431 } 432 /* 433 * don't want to use permitopen_port to avoid 434 * dependency on channels.[ch] here. 435 */ 436 if (cp == NULL || 437 (strcmp(cp, "*") != 0 && a2port(cp) <= 0)) { 438 free(tmp); 439 free(opt); 440 errstr = "invalid permitopen port"; 441 goto fail; 442 } 443 /* XXX - add streamlocal support */ 444 free(tmp); 445 /* Record it */ 446 oarray = ret->permitopen; 447 if ((ret->permitopen = recallocarray(ret->permitopen, 448 ret->npermitopen, ret->npermitopen + 1, 449 sizeof(*ret->permitopen))) == NULL) { 450 free(opt); 451 ret->permitopen = oarray; 452 goto alloc_fail; 453 } 454 ret->permitopen[ret->npermitopen++] = opt; 455 } else if (opt_match(&opts, "tunnel")) { 456 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 457 goto fail; 458 ret->force_tun_device = a2tun(opt, NULL); 459 free(opt); 460 if (ret->force_tun_device == SSH_TUNID_ERR) { 461 errstr = "invalid tun device"; 462 goto fail; 463 } 464 } 465 /* 466 * Skip the comma, and move to the next option 467 * (or break out if there are no more). 468 */ 469 if (*opts == '\0' || *opts == ' ' || *opts == '\t') 470 break; /* End of options. */ 471 /* Anything other than a comma is an unknown option */ 472 if (*opts != ',') { 473 errstr = "unknown key option"; 474 goto fail; 475 } 476 opts++; 477 if (*opts == '\0') { 478 errstr = "unexpected end-of-options"; 479 goto fail; 480 } 481 } 482 483 /* success */ 484 if (errstrp != NULL) 485 *errstrp = NULL; 486 return ret; 487 488 alloc_fail: 489 errstr = "memory allocation failed"; 490 fail: 491 sshauthopt_free(ret); 492 if (errstrp != NULL) 493 *errstrp = errstr; 494 return NULL; 495 } 496 497 struct sshauthopt * 498 sshauthopt_from_cert(struct sshkey *k) 499 { 500 struct sshauthopt *ret; 501 502 if (k == NULL || !sshkey_type_is_cert(k->type) || k->cert == NULL || 503 k->cert->type != SSH2_CERT_TYPE_USER) 504 return NULL; 505 506 if ((ret = sshauthopt_new()) == NULL) 507 return NULL; 508 509 /* Handle options and critical extensions separately */ 510 if (cert_option_list(ret, k->cert->critical, 511 OPTIONS_CRITICAL, 1) == -1) { 512 sshauthopt_free(ret); 513 return NULL; 514 } 515 if (cert_option_list(ret, k->cert->extensions, 516 OPTIONS_EXTENSIONS, 0) == -1) { 517 sshauthopt_free(ret); 518 return NULL; 519 } 520 /* success */ 521 return ret; 522 } 523 524 /* 525 * Merges "additional" options to "primary" and returns the result. 526 * NB. Some options from primary have primacy. 527 */ 528 struct sshauthopt * 529 sshauthopt_merge(const struct sshauthopt *primary, 530 const struct sshauthopt *additional, const char **errstrp) 531 { 532 struct sshauthopt *ret; 533 const char *errstr = "internal error"; 534 const char *tmp; 535 536 if (errstrp != NULL) 537 *errstrp = NULL; 538 539 if ((ret = sshauthopt_new()) == NULL) 540 goto alloc_fail; 541 542 /* cert_authority and cert_principals are cleared in result */ 543 544 /* Prefer access lists from primary. */ 545 /* XXX err is both set and mismatch? */ 546 tmp = primary->required_from_host_cert; 547 if (tmp == NULL) 548 tmp = additional->required_from_host_cert; 549 if (tmp != NULL && (ret->required_from_host_cert = strdup(tmp)) == NULL) 550 goto alloc_fail; 551 tmp = primary->required_from_host_keys; 552 if (tmp == NULL) 553 tmp = additional->required_from_host_keys; 554 if (tmp != NULL && (ret->required_from_host_keys = strdup(tmp)) == NULL) 555 goto alloc_fail; 556 557 /* force_tun_device, permitopen and environment prefer the primary. */ 558 ret->force_tun_device = primary->force_tun_device; 559 if (ret->force_tun_device == -1) 560 ret->force_tun_device = additional->force_tun_device; 561 if (primary->nenv > 0) { 562 if (dup_strings(&ret->env, &ret->nenv, 563 primary->env, primary->nenv) != 0) 564 goto alloc_fail; 565 } else if (additional->nenv) { 566 if (dup_strings(&ret->env, &ret->nenv, 567 additional->env, additional->nenv) != 0) 568 goto alloc_fail; 569 } 570 if (primary->npermitopen > 0) { 571 if (dup_strings(&ret->permitopen, &ret->npermitopen, 572 primary->permitopen, primary->npermitopen) != 0) 573 goto alloc_fail; 574 } else if (additional->npermitopen > 0) { 575 if (dup_strings(&ret->permitopen, &ret->npermitopen, 576 additional->permitopen, additional->npermitopen) != 0) 577 goto alloc_fail; 578 } 579 580 /* Flags are logical-AND (i.e. must be set in both for permission) */ 581 #define OPTFLAG(x) ret->x = (primary->x == 1) && (additional->x == 1) 582 OPTFLAG(permit_port_forwarding_flag); 583 OPTFLAG(permit_agent_forwarding_flag); 584 OPTFLAG(permit_x11_forwarding_flag); 585 OPTFLAG(permit_pty_flag); 586 OPTFLAG(permit_user_rc); 587 #undef OPTFLAG 588 589 /* Earliest expiry time should win */ 590 if (primary->valid_before != 0) 591 ret->valid_before = primary->valid_before; 592 if (additional->valid_before != 0 && 593 additional->valid_before < ret->valid_before) 594 ret->valid_before = additional->valid_before; 595 596 /* 597 * When both multiple forced-command are specified, only 598 * proceed if they are identical, otherwise fail. 599 */ 600 if (primary->force_command != NULL && 601 additional->force_command != NULL) { 602 if (strcmp(primary->force_command, 603 additional->force_command) == 0) { 604 /* ok */ 605 ret->force_command = strdup(primary->force_command); 606 if (ret->force_command == NULL) 607 goto alloc_fail; 608 } else { 609 errstr = "forced command options do not match"; 610 goto fail; 611 } 612 } else if (primary->force_command != NULL) { 613 if ((ret->force_command = strdup( 614 primary->force_command)) == NULL) 615 goto alloc_fail; 616 } else if (additional->force_command != NULL) { 617 if ((ret->force_command = strdup( 618 additional->force_command)) == NULL) 619 goto alloc_fail; 620 } 621 /* success */ 622 if (errstrp != NULL) 623 *errstrp = NULL; 624 return ret; 625 626 alloc_fail: 627 errstr = "memory allocation failed"; 628 fail: 629 if (errstrp != NULL) 630 *errstrp = errstr; 631 sshauthopt_free(ret); 632 return NULL; 633 } 634 635 /* 636 * Copy options 637 */ 638 struct sshauthopt * 639 sshauthopt_copy(const struct sshauthopt *orig) 640 { 641 struct sshauthopt *ret; 642 643 if ((ret = sshauthopt_new()) == NULL) 644 return NULL; 645 646 #define OPTSCALAR(x) ret->x = orig->x 647 OPTSCALAR(permit_port_forwarding_flag); 648 OPTSCALAR(permit_agent_forwarding_flag); 649 OPTSCALAR(permit_x11_forwarding_flag); 650 OPTSCALAR(permit_pty_flag); 651 OPTSCALAR(permit_user_rc); 652 OPTSCALAR(restricted); 653 OPTSCALAR(cert_authority); 654 OPTSCALAR(force_tun_device); 655 OPTSCALAR(valid_before); 656 #undef OPTSCALAR 657 #define OPTSTRING(x) \ 658 do { \ 659 if (orig->x != NULL && (ret->x = strdup(orig->x)) == NULL) { \ 660 sshauthopt_free(ret); \ 661 return NULL; \ 662 } \ 663 } while (0) 664 OPTSTRING(cert_principals); 665 OPTSTRING(force_command); 666 OPTSTRING(required_from_host_cert); 667 OPTSTRING(required_from_host_keys); 668 #undef OPTSTRING 669 670 if (dup_strings(&ret->env, &ret->nenv, orig->env, orig->nenv) != 0 || 671 dup_strings(&ret->permitopen, &ret->npermitopen, 672 orig->permitopen, orig->npermitopen) != 0) { 673 sshauthopt_free(ret); 674 return NULL; 675 } 676 return ret; 677 } 678 679 static int 680 serialise_array(struct sshbuf *m, char **a, size_t n) 681 { 682 struct sshbuf *b; 683 size_t i; 684 int r; 685 686 if (n > INT_MAX) 687 return SSH_ERR_INTERNAL_ERROR; 688 689 if ((b = sshbuf_new()) == NULL) { 690 return SSH_ERR_ALLOC_FAIL; 691 } 692 for (i = 0; i < n; i++) { 693 if ((r = sshbuf_put_cstring(b, a[i])) != 0) { 694 sshbuf_free(b); 695 return r; 696 } 697 } 698 if ((r = sshbuf_put_u32(m, n)) != 0 || 699 (r = sshbuf_put_stringb(m, b)) != 0) { 700 sshbuf_free(b); 701 return r; 702 } 703 /* success */ 704 return 0; 705 } 706 707 static int 708 deserialise_array(struct sshbuf *m, char ***ap, size_t *np) 709 { 710 char **a = NULL; 711 size_t i, n = 0; 712 struct sshbuf *b = NULL; 713 u_int tmp; 714 int r = SSH_ERR_INTERNAL_ERROR; 715 716 if ((r = sshbuf_get_u32(m, &tmp)) != 0 || 717 (r = sshbuf_froms(m, &b)) != 0) 718 goto out; 719 if (tmp > INT_MAX) { 720 r = SSH_ERR_INVALID_FORMAT; 721 goto out; 722 } 723 n = tmp; 724 if (n > 0 && (a = calloc(n, sizeof(*a))) == NULL) { 725 r = SSH_ERR_ALLOC_FAIL; 726 goto out; 727 } 728 for (i = 0; i < n; i++) { 729 if ((r = sshbuf_get_cstring(b, &a[i], NULL)) != 0) 730 goto out; 731 } 732 /* success */ 733 r = 0; 734 *ap = a; 735 a = NULL; 736 *np = n; 737 n = 0; 738 out: 739 for (i = 0; i < n; i++) 740 free(a[i]); 741 free(a); 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 and simple integer 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_u64(m, opts->valid_before)) != 0) 785 return r; 786 787 /* tunnel number can be negative to indicate "unset" */ 788 if ((r = sshbuf_put_u8(m, opts->force_tun_device == -1)) != 0 || 789 (r = sshbuf_put_u32(m, (opts->force_tun_device < 0) ? 790 0 : (u_int)opts->force_tun_device)) != 0) 791 return r; 792 793 /* String options; these may be NULL */ 794 if ((r = serialise_nullable_string(m, 795 untrusted ? "yes" : opts->cert_principals)) != 0 || 796 (r = serialise_nullable_string(m, 797 untrusted ? "true" : opts->force_command)) != 0 || 798 (r = serialise_nullable_string(m, 799 untrusted ? NULL : opts->required_from_host_cert)) != 0 || 800 (r = serialise_nullable_string(m, 801 untrusted ? NULL : opts->required_from_host_keys)) != 0) 802 return r; 803 804 /* Array options */ 805 if ((r = serialise_array(m, opts->env, 806 untrusted ? 0 : opts->nenv)) != 0 || 807 (r = serialise_array(m, opts->permitopen, 808 untrusted ? 0 : opts->npermitopen)) != 0) 809 return r; 810 811 /* success */ 812 return 0; 813 } 814 815 int 816 sshauthopt_deserialise(struct sshbuf *m, struct sshauthopt **optsp) 817 { 818 struct sshauthopt *opts = NULL; 819 int r = SSH_ERR_INTERNAL_ERROR; 820 u_char f; 821 u_int tmp; 822 823 if ((opts = calloc(1, sizeof(*opts))) == NULL) 824 return SSH_ERR_ALLOC_FAIL; 825 826 #define OPT_FLAG(x) \ 827 do { \ 828 if ((r = sshbuf_get_u8(m, &f)) != 0) \ 829 goto out; \ 830 opts->x = f; \ 831 } while (0) 832 OPT_FLAG(permit_port_forwarding_flag); 833 OPT_FLAG(permit_agent_forwarding_flag); 834 OPT_FLAG(permit_x11_forwarding_flag); 835 OPT_FLAG(permit_pty_flag); 836 OPT_FLAG(permit_user_rc); 837 OPT_FLAG(restricted); 838 OPT_FLAG(cert_authority); 839 #undef OPT_FLAG 840 841 if ((r = sshbuf_get_u64(m, &opts->valid_before)) != 0) 842 goto out; 843 844 /* tunnel number can be negative to indicate "unset" */ 845 if ((r = sshbuf_get_u8(m, &f)) != 0 || 846 (r = sshbuf_get_u32(m, &tmp)) != 0) 847 goto out; 848 opts->force_tun_device = f ? -1 : (int)tmp; 849 850 /* String options may be NULL */ 851 if ((r = deserialise_nullable_string(m, &opts->cert_principals)) != 0 || 852 (r = deserialise_nullable_string(m, &opts->force_command)) != 0 || 853 (r = deserialise_nullable_string(m, 854 &opts->required_from_host_cert)) != 0 || 855 (r = deserialise_nullable_string(m, 856 &opts->required_from_host_keys)) != 0) 857 goto out; 858 859 /* Array options */ 860 if ((r = deserialise_array(m, &opts->env, &opts->nenv)) != 0 || 861 (r = deserialise_array(m, 862 &opts->permitopen, &opts->npermitopen)) != 0) 863 goto out; 864 865 /* success */ 866 r = 0; 867 *optsp = opts; 868 opts = NULL; 869 out: 870 sshauthopt_free(opts); 871 return r; 872 } 873