1 /* $OpenBSD: auth-options.c,v 1.76 2018/03/03 03:15:51 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 <sys/types.h> 19 #include <sys/queue.h> 20 21 #include <netdb.h> 22 #include <pwd.h> 23 #include <string.h> 24 #include <stdio.h> 25 #include <stdarg.h> 26 #include <ctype.h> 27 #include <limits.h> 28 29 #include "xmalloc.h" 30 #include "ssherr.h" 31 #include "log.h" 32 #include "sshbuf.h" 33 #include "misc.h" 34 #include "sshkey.h" 35 #include "match.h" 36 #include "ssh2.h" 37 #include "auth-options.h" 38 39 /* 40 * Match flag 'opt' in *optsp, and if allow_negate is set then also match 41 * 'no-opt'. Returns -1 if option not matched, 1 if option matches or 0 42 * if negated option matches. 43 * If the option or negated option matches, then *optsp is updated to 44 * point to the first character after the option. 45 */ 46 static int 47 opt_flag(const char *opt, int allow_negate, const char **optsp) 48 { 49 size_t opt_len = strlen(opt); 50 const char *opts = *optsp; 51 int negate = 0; 52 53 if (allow_negate && strncasecmp(opts, "no-", 3) == 0) { 54 opts += 3; 55 negate = 1; 56 } 57 if (strncasecmp(opts, opt, opt_len) == 0) { 58 *optsp = opts + opt_len; 59 return negate ? 0 : 1; 60 } 61 return -1; 62 } 63 64 static char * 65 opt_dequote(const char **sp, const char **errstrp) 66 { 67 const char *s = *sp; 68 char *ret; 69 size_t i; 70 71 *errstrp = NULL; 72 if (*s != '"') { 73 *errstrp = "missing start quote"; 74 return NULL; 75 } 76 s++; 77 if ((ret = malloc(strlen((s)) + 1)) == NULL) { 78 *errstrp = "memory allocation failed"; 79 return NULL; 80 } 81 for (i = 0; *s != '\0' && *s != '"';) { 82 if (s[0] == '\\' && s[1] == '"') 83 s++; 84 ret[i++] = *s++; 85 } 86 if (*s == '\0') { 87 *errstrp = "missing end quote"; 88 free(ret); 89 return NULL; 90 } 91 ret[i] = '\0'; 92 s++; 93 *sp = s; 94 return ret; 95 } 96 97 static int 98 opt_match(const char **opts, const char *term) 99 { 100 if (strncasecmp((*opts), term, strlen(term)) == 0 && 101 (*opts)[strlen(term)] == '=') { 102 *opts += strlen(term) + 1; 103 return 1; 104 } 105 return 0; 106 } 107 108 static int 109 dup_strings(char ***dstp, size_t *ndstp, char **src, size_t nsrc) 110 { 111 char **dst; 112 size_t i, j; 113 114 *dstp = NULL; 115 *ndstp = 0; 116 if (nsrc == 0) 117 return 0; 118 119 if ((dst = calloc(nsrc, sizeof(*src))) == NULL) 120 return -1; 121 for (i = 0; i < nsrc; i++) { 122 if ((dst[i] = strdup(src[i])) == NULL) { 123 for (j = 0; j < i; j++) 124 free(dst[j]); 125 free(dst); 126 return -1; 127 } 128 } 129 /* success */ 130 *dstp = dst; 131 *ndstp = nsrc; 132 return 0; 133 } 134 135 #define OPTIONS_CRITICAL 1 136 #define OPTIONS_EXTENSIONS 2 137 static int 138 cert_option_list(struct sshauthopt *opts, struct sshbuf *oblob, 139 u_int which, int crit) 140 { 141 char *command, *allowed; 142 char *name = NULL; 143 struct sshbuf *c = NULL, *data = NULL; 144 int r, ret = -1, found; 145 146 if ((c = sshbuf_fromb(oblob)) == NULL) { 147 error("%s: sshbuf_fromb failed", __func__); 148 goto out; 149 } 150 151 while (sshbuf_len(c) > 0) { 152 sshbuf_free(data); 153 data = NULL; 154 if ((r = sshbuf_get_cstring(c, &name, NULL)) != 0 || 155 (r = sshbuf_froms(c, &data)) != 0) { 156 error("Unable to parse certificate options: %s", 157 ssh_err(r)); 158 goto out; 159 } 160 debug3("found certificate option \"%.100s\" len %zu", 161 name, sshbuf_len(data)); 162 found = 0; 163 if ((which & OPTIONS_EXTENSIONS) != 0) { 164 if (strcmp(name, "permit-X11-forwarding") == 0) { 165 opts->permit_x11_forwarding_flag = 1; 166 found = 1; 167 } else if (strcmp(name, 168 "permit-agent-forwarding") == 0) { 169 opts->permit_agent_forwarding_flag = 1; 170 found = 1; 171 } else if (strcmp(name, 172 "permit-port-forwarding") == 0) { 173 opts->permit_port_forwarding_flag = 1; 174 found = 1; 175 } else if (strcmp(name, "permit-pty") == 0) { 176 opts->permit_pty_flag = 1; 177 found = 1; 178 } else if (strcmp(name, "permit-user-rc") == 0) { 179 opts->permit_user_rc = 1; 180 found = 1; 181 } 182 } 183 if (!found && (which & OPTIONS_CRITICAL) != 0) { 184 if (strcmp(name, "force-command") == 0) { 185 if ((r = sshbuf_get_cstring(data, &command, 186 NULL)) != 0) { 187 error("Unable to parse \"%s\" " 188 "section: %s", name, ssh_err(r)); 189 goto out; 190 } 191 if (opts->force_command != NULL) { 192 error("Certificate has multiple " 193 "force-command options"); 194 free(command); 195 goto out; 196 } 197 opts->force_command = command; 198 found = 1; 199 } 200 if (strcmp(name, "source-address") == 0) { 201 if ((r = sshbuf_get_cstring(data, &allowed, 202 NULL)) != 0) { 203 error("Unable to parse \"%s\" " 204 "section: %s", name, ssh_err(r)); 205 goto out; 206 } 207 if (opts->required_from_host_cert != NULL) { 208 error("Certificate has multiple " 209 "source-address options"); 210 free(allowed); 211 goto out; 212 } 213 /* Check syntax */ 214 if (addr_match_cidr_list(NULL, allowed) == -1) { 215 error("Certificate source-address " 216 "contents invalid"); 217 goto out; 218 } 219 opts->required_from_host_cert = allowed; 220 found = 1; 221 } 222 } 223 224 if (!found) { 225 if (crit) { 226 error("Certificate critical option \"%s\" " 227 "is not supported", name); 228 goto out; 229 } else { 230 logit("Certificate extension \"%s\" " 231 "is not supported", name); 232 } 233 } else if (sshbuf_len(data) != 0) { 234 error("Certificate option \"%s\" corrupt " 235 "(extra data)", name); 236 goto out; 237 } 238 free(name); 239 name = NULL; 240 } 241 /* successfully parsed all options */ 242 ret = 0; 243 244 out: 245 free(name); 246 sshbuf_free(data); 247 sshbuf_free(c); 248 return ret; 249 } 250 251 struct sshauthopt * 252 sshauthopt_new(void) 253 { 254 struct sshauthopt *ret; 255 256 if ((ret = calloc(1, sizeof(*ret))) == NULL) 257 return NULL; 258 ret->force_tun_device = -1; 259 return ret; 260 } 261 262 void 263 sshauthopt_free(struct sshauthopt *opts) 264 { 265 size_t i; 266 267 if (opts == NULL) 268 return; 269 270 free(opts->cert_principals); 271 free(opts->force_command); 272 free(opts->required_from_host_cert); 273 free(opts->required_from_host_keys); 274 275 for (i = 0; i < opts->nenv; i++) 276 free(opts->env[i]); 277 free(opts->env); 278 279 for (i = 0; i < opts->npermitopen; i++) 280 free(opts->permitopen[i]); 281 free(opts->permitopen); 282 283 explicit_bzero(opts, sizeof(*opts)); 284 free(opts); 285 } 286 287 struct sshauthopt * 288 sshauthopt_new_with_keys_defaults(void) 289 { 290 struct sshauthopt *ret = NULL; 291 292 if ((ret = sshauthopt_new()) == NULL) 293 return NULL; 294 295 /* Defaults for authorized_keys flags */ 296 ret->permit_port_forwarding_flag = 1; 297 ret->permit_agent_forwarding_flag = 1; 298 ret->permit_x11_forwarding_flag = 1; 299 ret->permit_pty_flag = 1; 300 ret->permit_user_rc = 1; 301 return ret; 302 } 303 304 struct sshauthopt * 305 sshauthopt_parse(const char *opts, const char **errstrp) 306 { 307 char **oarray, *opt, *cp, *tmp, *host; 308 int r; 309 struct sshauthopt *ret = NULL; 310 const char *errstr = "unknown error"; 311 312 if (errstrp != NULL) 313 *errstrp = NULL; 314 if ((ret = sshauthopt_new_with_keys_defaults()) == NULL) 315 goto alloc_fail; 316 317 if (opts == NULL) 318 return ret; 319 320 while (*opts && *opts != ' ' && *opts != '\t') { 321 /* flag options */ 322 if ((r = opt_flag("restrict", 0, &opts)) != -1) { 323 ret->restricted = 1; 324 ret->permit_port_forwarding_flag = 0; 325 ret->permit_agent_forwarding_flag = 0; 326 ret->permit_x11_forwarding_flag = 0; 327 ret->permit_pty_flag = 0; 328 ret->permit_user_rc = 0; 329 } else if ((r = opt_flag("cert-authority", 0, &opts)) != -1) { 330 ret->cert_authority = r; 331 } else if ((r = opt_flag("port-forwarding", 1, &opts)) != -1) { 332 ret->permit_port_forwarding_flag = r == 1; 333 } else if ((r = opt_flag("agent-forwarding", 1, &opts)) != -1) { 334 ret->permit_agent_forwarding_flag = r == 1; 335 } else if ((r = opt_flag("x11-forwarding", 1, &opts)) != -1) { 336 ret->permit_x11_forwarding_flag = r == 1; 337 } else if ((r = opt_flag("pty", 1, &opts)) != -1) { 338 ret->permit_pty_flag = r == 1; 339 } else if ((r = opt_flag("user-rc", 1, &opts)) != -1) { 340 ret->permit_user_rc = r == 1; 341 } else if (opt_match(&opts, "command")) { 342 if (ret->force_command != NULL) { 343 errstr = "multiple \"command\" clauses"; 344 goto fail; 345 } 346 ret->force_command = opt_dequote(&opts, &errstr); 347 if (ret->force_command == NULL) 348 goto fail; 349 } else if (opt_match(&opts, "principals")) { 350 if (ret->cert_principals != NULL) { 351 errstr = "multiple \"principals\" clauses"; 352 goto fail; 353 } 354 ret->cert_principals = opt_dequote(&opts, &errstr); 355 if (ret->cert_principals == NULL) 356 goto fail; 357 } else if (opt_match(&opts, "from")) { 358 if (ret->required_from_host_keys != NULL) { 359 errstr = "multiple \"from\" clauses"; 360 goto fail; 361 } 362 ret->required_from_host_keys = opt_dequote(&opts, 363 &errstr); 364 if (ret->required_from_host_keys == NULL) 365 goto fail; 366 } else if (opt_match(&opts, "environment")) { 367 if (ret->nenv > INT_MAX) { 368 errstr = "too many environment strings"; 369 goto fail; 370 } 371 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 372 goto fail; 373 /* env name must be alphanumeric and followed by '=' */ 374 if ((tmp = strchr(opt, '=')) == NULL) { 375 free(opt); 376 errstr = "invalid environment string"; 377 goto fail; 378 } 379 for (cp = opt; cp < tmp; cp++) { 380 if (!isalnum((u_char)*cp)) { 381 free(opt); 382 errstr = "invalid environment string"; 383 goto fail; 384 } 385 } 386 /* Append it. */ 387 oarray = ret->env; 388 if ((ret->env = recallocarray(ret->env, ret->nenv, 389 ret->nenv + 1, sizeof(*ret->env))) == NULL) { 390 free(opt); 391 ret->env = oarray; /* put it back for cleanup */ 392 goto alloc_fail; 393 } 394 ret->env[ret->nenv++] = opt; 395 } else if (opt_match(&opts, "permitopen")) { 396 if (ret->npermitopen > INT_MAX) { 397 errstr = "too many permitopens"; 398 goto fail; 399 } 400 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 401 goto fail; 402 if ((tmp = strdup(opt)) == NULL) { 403 free(opt); 404 goto alloc_fail; 405 } 406 cp = tmp; 407 /* validate syntax of permitopen before recording it. */ 408 host = hpdelim(&cp); 409 if (host == NULL || strlen(host) >= NI_MAXHOST) { 410 free(tmp); 411 free(opt); 412 errstr = "invalid permitopen hostname"; 413 goto fail; 414 } 415 /* 416 * don't want to use permitopen_port to avoid 417 * dependency on channels.[ch] here. 418 */ 419 if (cp == NULL || 420 (strcmp(cp, "*") != 0 && a2port(cp) <= 0)) { 421 free(tmp); 422 free(opt); 423 errstr = "invalid permitopen port"; 424 goto fail; 425 } 426 /* XXX - add streamlocal support */ 427 free(tmp); 428 /* Record it */ 429 oarray = ret->permitopen; 430 if ((ret->permitopen = recallocarray(ret->permitopen, 431 ret->npermitopen, ret->npermitopen + 1, 432 sizeof(*ret->permitopen))) == NULL) { 433 free(opt); 434 ret->permitopen = oarray; 435 goto alloc_fail; 436 } 437 ret->permitopen[ret->npermitopen++] = opt; 438 } else if (opt_match(&opts, "tunnel")) { 439 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 440 goto fail; 441 ret->force_tun_device = a2tun(opt, NULL); 442 free(opt); 443 if (ret->force_tun_device == SSH_TUNID_ERR) { 444 errstr = "invalid tun device"; 445 goto fail; 446 } 447 } 448 /* 449 * Skip the comma, and move to the next option 450 * (or break out if there are no more). 451 */ 452 if (*opts == '\0' || *opts == ' ' || *opts == '\t') 453 break; /* End of options. */ 454 /* Anything other than a comma is an unknown option */ 455 if (*opts != ',') { 456 errstr = "unknown key option"; 457 goto fail; 458 } 459 opts++; 460 if (*opts == '\0') { 461 errstr = "unexpected end-of-options"; 462 goto fail; 463 } 464 } 465 466 /* success */ 467 if (errstrp != NULL) 468 *errstrp = NULL; 469 return ret; 470 471 alloc_fail: 472 errstr = "memory allocation failed"; 473 fail: 474 sshauthopt_free(ret); 475 if (errstrp != NULL) 476 *errstrp = errstr; 477 return NULL; 478 } 479 480 struct sshauthopt * 481 sshauthopt_from_cert(struct sshkey *k) 482 { 483 struct sshauthopt *ret; 484 485 if (k == NULL || !sshkey_type_is_cert(k->type) || k->cert == NULL || 486 k->cert->type != SSH2_CERT_TYPE_USER) 487 return NULL; 488 489 if ((ret = sshauthopt_new()) == NULL) 490 return NULL; 491 492 /* Handle options and critical extensions separately */ 493 if (cert_option_list(ret, k->cert->critical, 494 OPTIONS_CRITICAL, 1) == -1) { 495 sshauthopt_free(ret); 496 return NULL; 497 } 498 if (cert_option_list(ret, k->cert->extensions, 499 OPTIONS_EXTENSIONS, 0) == -1) { 500 sshauthopt_free(ret); 501 return NULL; 502 } 503 /* success */ 504 return ret; 505 } 506 507 /* 508 * Merges "additional" options to "primary" and returns the result. 509 * NB. Some options from primary have primacy. 510 */ 511 struct sshauthopt * 512 sshauthopt_merge(const struct sshauthopt *primary, 513 const struct sshauthopt *additional, const char **errstrp) 514 { 515 struct sshauthopt *ret; 516 const char *errstr = "internal error"; 517 const char *tmp; 518 519 if (errstrp != NULL) 520 *errstrp = NULL; 521 522 if ((ret = sshauthopt_new()) == NULL) 523 goto alloc_fail; 524 525 /* cert_authority and cert_principals are cleared in result */ 526 527 /* Prefer access lists from primary. */ 528 /* XXX err is both set and mismatch? */ 529 tmp = primary->required_from_host_cert; 530 if (tmp == NULL) 531 tmp = additional->required_from_host_cert; 532 if (tmp != NULL && (ret->required_from_host_cert = strdup(tmp)) == NULL) 533 goto alloc_fail; 534 tmp = primary->required_from_host_keys; 535 if (tmp == NULL) 536 tmp = additional->required_from_host_keys; 537 if (tmp != NULL && (ret->required_from_host_keys = strdup(tmp)) == NULL) 538 goto alloc_fail; 539 540 /* force_tun_device, permitopen and environment prefer the primary. */ 541 ret->force_tun_device = primary->force_tun_device; 542 if (ret->force_tun_device == -1) 543 ret->force_tun_device = additional->force_tun_device; 544 if (primary->nenv > 0) { 545 if (dup_strings(&ret->env, &ret->nenv, 546 primary->env, primary->nenv) != 0) 547 goto alloc_fail; 548 } else if (additional->nenv) { 549 if (dup_strings(&ret->env, &ret->nenv, 550 additional->env, additional->nenv) != 0) 551 goto alloc_fail; 552 } 553 if (primary->npermitopen > 0) { 554 if (dup_strings(&ret->permitopen, &ret->npermitopen, 555 primary->permitopen, primary->npermitopen) != 0) 556 goto alloc_fail; 557 } else if (additional->npermitopen > 0) { 558 if (dup_strings(&ret->permitopen, &ret->npermitopen, 559 additional->permitopen, additional->npermitopen) != 0) 560 goto alloc_fail; 561 } 562 563 /* Flags are logical-AND (i.e. must be set in both for permission) */ 564 #define OPTFLAG(x) ret->x = (primary->x == 1) && (additional->x == 1) 565 OPTFLAG(permit_port_forwarding_flag); 566 OPTFLAG(permit_agent_forwarding_flag); 567 OPTFLAG(permit_x11_forwarding_flag); 568 OPTFLAG(permit_pty_flag); 569 OPTFLAG(permit_user_rc); 570 #undef OPTFLAG 571 572 /* 573 * When both multiple forced-command are specified, only 574 * proceed if they are identical, otherwise fail. 575 */ 576 if (primary->force_command != NULL && 577 additional->force_command != NULL) { 578 if (strcmp(primary->force_command, 579 additional->force_command) == 0) { 580 /* ok */ 581 ret->force_command = strdup(primary->force_command); 582 if (ret->force_command == NULL) 583 goto alloc_fail; 584 } else { 585 errstr = "forced command options do not match"; 586 goto fail; 587 } 588 } else if (primary->force_command != NULL) { 589 if ((ret->force_command = strdup( 590 primary->force_command)) == NULL) 591 goto alloc_fail; 592 } else if (additional->force_command != NULL) { 593 if ((ret->force_command = strdup( 594 additional->force_command)) == NULL) 595 goto alloc_fail; 596 } 597 /* success */ 598 if (errstrp != NULL) 599 *errstrp = NULL; 600 return ret; 601 602 alloc_fail: 603 errstr = "memory allocation failed"; 604 fail: 605 if (errstrp != NULL) 606 *errstrp = errstr; 607 sshauthopt_free(ret); 608 return NULL; 609 } 610 611 /* 612 * Copy options 613 */ 614 struct sshauthopt * 615 sshauthopt_copy(const struct sshauthopt *orig) 616 { 617 struct sshauthopt *ret; 618 619 if ((ret = sshauthopt_new()) == NULL) 620 return NULL; 621 622 #define OPTSCALAR(x) ret->x = orig->x 623 OPTSCALAR(permit_port_forwarding_flag); 624 OPTSCALAR(permit_agent_forwarding_flag); 625 OPTSCALAR(permit_x11_forwarding_flag); 626 OPTSCALAR(permit_pty_flag); 627 OPTSCALAR(permit_user_rc); 628 OPTSCALAR(restricted); 629 OPTSCALAR(cert_authority); 630 OPTSCALAR(force_tun_device); 631 #undef OPTSCALAR 632 #define OPTSTRING(x) \ 633 do { \ 634 if (orig->x != NULL && (ret->x = strdup(orig->x)) == NULL) { \ 635 sshauthopt_free(ret); \ 636 return NULL; \ 637 } \ 638 } while (0) 639 OPTSTRING(cert_principals); 640 OPTSTRING(force_command); 641 OPTSTRING(required_from_host_cert); 642 OPTSTRING(required_from_host_keys); 643 #undef OPTSTRING 644 645 if (dup_strings(&ret->env, &ret->nenv, orig->env, orig->nenv) != 0 || 646 dup_strings(&ret->permitopen, &ret->npermitopen, 647 orig->permitopen, orig->npermitopen) != 0) { 648 sshauthopt_free(ret); 649 return NULL; 650 } 651 return ret; 652 } 653 654 static int 655 serialise_array(struct sshbuf *m, char **a, size_t n) 656 { 657 struct sshbuf *b; 658 size_t i; 659 int r; 660 661 if (n > INT_MAX) 662 return SSH_ERR_INTERNAL_ERROR; 663 664 if ((b = sshbuf_new()) == NULL) { 665 return SSH_ERR_ALLOC_FAIL; 666 } 667 for (i = 0; i < n; i++) { 668 if ((r = sshbuf_put_cstring(b, a[i])) != 0) { 669 sshbuf_free(b); 670 return r; 671 } 672 } 673 if ((r = sshbuf_put_u32(m, n)) != 0 || 674 (r = sshbuf_put_stringb(m, b)) != 0) { 675 sshbuf_free(b); 676 return r; 677 } 678 /* success */ 679 return 0; 680 } 681 682 static int 683 deserialise_array(struct sshbuf *m, char ***ap, size_t *np) 684 { 685 char **a = NULL; 686 size_t i, n = 0; 687 struct sshbuf *b = NULL; 688 u_int tmp; 689 int r = SSH_ERR_INTERNAL_ERROR; 690 691 if ((r = sshbuf_get_u32(m, &tmp)) != 0 || 692 (r = sshbuf_froms(m, &b)) != 0) 693 goto out; 694 if (tmp > INT_MAX) { 695 r = SSH_ERR_INVALID_FORMAT; 696 goto out; 697 } 698 n = tmp; 699 if (n > 0 && (a = calloc(n, sizeof(*a))) == NULL) { 700 r = SSH_ERR_ALLOC_FAIL; 701 goto out; 702 } 703 for (i = 0; i < n; i++) { 704 if ((r = sshbuf_get_cstring(b, &a[i], NULL)) != 0) 705 goto out; 706 } 707 /* success */ 708 r = 0; 709 *ap = a; 710 a = NULL; 711 *np = n; 712 n = 0; 713 out: 714 for (i = 0; i < n; i++) 715 free(a[i]); 716 free(a); 717 sshbuf_free(b); 718 return r; 719 } 720 721 static int 722 serialise_nullable_string(struct sshbuf *m, const char *s) 723 { 724 int r; 725 726 if ((r = sshbuf_put_u8(m, s == NULL)) != 0 || 727 (r = sshbuf_put_cstring(m, s)) != 0) 728 return r; 729 return 0; 730 } 731 732 static int 733 deserialise_nullable_string(struct sshbuf *m, char **sp) 734 { 735 int r; 736 u_char flag; 737 738 *sp = NULL; 739 if ((r = sshbuf_get_u8(m, &flag)) != 0 || 740 (r = sshbuf_get_cstring(m, flag ? NULL : sp, NULL)) != 0) 741 return r; 742 return 0; 743 } 744 745 int 746 sshauthopt_serialise(const struct sshauthopt *opts, struct sshbuf *m, 747 int untrusted) 748 { 749 int r = SSH_ERR_INTERNAL_ERROR; 750 751 /* Flag options */ 752 if ((r = sshbuf_put_u8(m, opts->permit_port_forwarding_flag)) != 0 || 753 (r = sshbuf_put_u8(m, opts->permit_agent_forwarding_flag)) != 0 || 754 (r = sshbuf_put_u8(m, opts->permit_x11_forwarding_flag)) != 0 || 755 (r = sshbuf_put_u8(m, opts->permit_pty_flag)) != 0 || 756 (r = sshbuf_put_u8(m, opts->permit_user_rc)) != 0 || 757 (r = sshbuf_put_u8(m, opts->restricted)) != 0 || 758 (r = sshbuf_put_u8(m, opts->cert_authority)) != 0) 759 return r; 760 761 /* tunnel number can be negative to indicate "unset" */ 762 if ((r = sshbuf_put_u8(m, opts->force_tun_device == -1)) != 0 || 763 (r = sshbuf_put_u32(m, (opts->force_tun_device < 0) ? 764 0 : (u_int)opts->force_tun_device)) != 0) 765 return r; 766 767 /* String options; these may be NULL */ 768 if ((r = serialise_nullable_string(m, 769 untrusted ? "yes" : opts->cert_principals)) != 0 || 770 (r = serialise_nullable_string(m, 771 untrusted ? "true" : opts->force_command)) != 0 || 772 (r = serialise_nullable_string(m, 773 untrusted ? NULL : opts->required_from_host_cert)) != 0 || 774 (r = serialise_nullable_string(m, 775 untrusted ? NULL : opts->required_from_host_keys)) != 0) 776 return r; 777 778 /* Array options */ 779 if ((r = serialise_array(m, opts->env, 780 untrusted ? 0 : opts->nenv)) != 0 || 781 (r = serialise_array(m, opts->permitopen, 782 untrusted ? 0 : opts->npermitopen)) != 0) 783 return r; 784 785 /* success */ 786 return 0; 787 } 788 789 int 790 sshauthopt_deserialise(struct sshbuf *m, struct sshauthopt **optsp) 791 { 792 struct sshauthopt *opts = NULL; 793 int r = SSH_ERR_INTERNAL_ERROR; 794 u_char f; 795 u_int tmp; 796 797 if ((opts = calloc(1, sizeof(*opts))) == NULL) 798 return SSH_ERR_ALLOC_FAIL; 799 800 #define OPT_FLAG(x) \ 801 do { \ 802 if ((r = sshbuf_get_u8(m, &f)) != 0) \ 803 goto out; \ 804 opts->x = f; \ 805 } while (0) 806 OPT_FLAG(permit_port_forwarding_flag); 807 OPT_FLAG(permit_agent_forwarding_flag); 808 OPT_FLAG(permit_x11_forwarding_flag); 809 OPT_FLAG(permit_pty_flag); 810 OPT_FLAG(permit_user_rc); 811 OPT_FLAG(restricted); 812 OPT_FLAG(cert_authority); 813 #undef OPT_FLAG 814 815 /* tunnel number can be negative to indicate "unset" */ 816 if ((r = sshbuf_get_u8(m, &f)) != 0 || 817 (r = sshbuf_get_u32(m, &tmp)) != 0) 818 goto out; 819 opts->force_tun_device = f ? -1 : (int)tmp; 820 821 /* String options may be NULL */ 822 if ((r = deserialise_nullable_string(m, &opts->cert_principals)) != 0 || 823 (r = deserialise_nullable_string(m, &opts->force_command)) != 0 || 824 (r = deserialise_nullable_string(m, 825 &opts->required_from_host_cert)) != 0 || 826 (r = deserialise_nullable_string(m, 827 &opts->required_from_host_keys)) != 0) 828 goto out; 829 830 /* Array options */ 831 if ((r = deserialise_array(m, &opts->env, &opts->nenv)) != 0 || 832 (r = deserialise_array(m, 833 &opts->permitopen, &opts->npermitopen)) != 0) 834 goto out; 835 836 /* success */ 837 r = 0; 838 *optsp = opts; 839 opts = NULL; 840 out: 841 sshauthopt_free(opts); 842 return r; 843 } 844