1 /* $OpenBSD: auth-options.c,v 1.102 2025/09/15 04:38:00 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 #include <sys/queue.h> 22 23 #include <stdlib.h> 24 #include <netdb.h> 25 #include <pwd.h> 26 #include <string.h> 27 #include <stdio.h> 28 #include <stdint.h> 29 #include <stdarg.h> 30 #include <ctype.h> 31 #include <limits.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 52 if (nsrc == 0) 53 return 0; 54 if (nsrc >= SIZE_MAX / sizeof(*src) || 55 (dst = calloc(nsrc, sizeof(*src))) == NULL) 56 return -1; 57 for (i = 0; i < nsrc; i++) { 58 if ((dst[i] = strdup(src[i])) == NULL) { 59 for (j = 0; j < i; j++) 60 free(dst[j]); 61 free(dst); 62 return -1; 63 } 64 } 65 /* success */ 66 *dstp = dst; 67 *ndstp = nsrc; 68 return 0; 69 } 70 71 #define OPTIONS_CRITICAL 1 72 #define OPTIONS_EXTENSIONS 2 73 static int 74 cert_option_list(struct sshauthopt *opts, struct sshbuf *oblob, 75 u_int which, int crit) 76 { 77 char *command, *allowed; 78 char *name = NULL; 79 struct sshbuf *c = NULL, *data = NULL; 80 int r, ret = -1, found; 81 82 if ((c = sshbuf_fromb(oblob)) == NULL) { 83 error_f("sshbuf_fromb failed"); 84 goto out; 85 } 86 87 while (sshbuf_len(c) > 0) { 88 sshbuf_free(data); 89 data = NULL; 90 if ((r = sshbuf_get_cstring(c, &name, NULL)) != 0 || 91 (r = sshbuf_froms(c, &data)) != 0) { 92 error_r(r, "Unable to parse certificate options"); 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, "verify-required") == 0) { 123 opts->require_verify = 1; 124 found = 1; 125 } else if (strcmp(name, "force-command") == 0) { 126 if ((r = sshbuf_get_cstring(data, &command, 127 NULL)) != 0) { 128 error_r(r, "Unable to parse \"%s\" " 129 "section", name); 130 goto out; 131 } 132 if (opts->force_command != NULL) { 133 error("Certificate has multiple " 134 "force-command options"); 135 free(command); 136 goto out; 137 } 138 opts->force_command = command; 139 found = 1; 140 } else if (strcmp(name, "source-address") == 0) { 141 if ((r = sshbuf_get_cstring(data, &allowed, 142 NULL)) != 0) { 143 error_r(r, "Unable to parse \"%s\" " 144 "section", name); 145 goto out; 146 } 147 if (opts->required_from_host_cert != NULL) { 148 error("Certificate has multiple " 149 "source-address options"); 150 free(allowed); 151 goto out; 152 } 153 /* Check syntax */ 154 if (addr_match_cidr_list(NULL, allowed) == -1) { 155 error("Certificate source-address " 156 "contents invalid"); 157 free(allowed); 158 goto out; 159 } 160 opts->required_from_host_cert = allowed; 161 found = 1; 162 } 163 } 164 165 if (!found) { 166 if (crit) { 167 error("Certificate critical option \"%s\" " 168 "is not supported", name); 169 goto out; 170 } else { 171 logit("Certificate extension \"%s\" " 172 "is not supported", name); 173 } 174 } else if (sshbuf_len(data) != 0) { 175 error("Certificate option \"%s\" corrupt " 176 "(extra data)", name); 177 goto out; 178 } 179 free(name); 180 name = NULL; 181 } 182 /* successfully parsed all options */ 183 ret = 0; 184 185 out: 186 free(name); 187 sshbuf_free(data); 188 sshbuf_free(c); 189 return ret; 190 } 191 192 struct sshauthopt * 193 sshauthopt_new(void) 194 { 195 struct sshauthopt *ret; 196 197 if ((ret = calloc(1, sizeof(*ret))) == NULL) 198 return NULL; 199 ret->force_tun_device = -1; 200 return ret; 201 } 202 203 void 204 sshauthopt_free(struct sshauthopt *opts) 205 { 206 size_t i; 207 208 if (opts == NULL) 209 return; 210 211 free(opts->cert_principals); 212 free(opts->force_command); 213 free(opts->required_from_host_cert); 214 free(opts->required_from_host_keys); 215 216 for (i = 0; i < opts->nenv; i++) 217 free(opts->env[i]); 218 free(opts->env); 219 220 for (i = 0; i < opts->npermitopen; i++) 221 free(opts->permitopen[i]); 222 free(opts->permitopen); 223 224 for (i = 0; i < opts->npermitlisten; i++) 225 free(opts->permitlisten[i]); 226 free(opts->permitlisten); 227 228 freezero(opts, sizeof(*opts)); 229 } 230 231 struct sshauthopt * 232 sshauthopt_new_with_keys_defaults(void) 233 { 234 struct sshauthopt *ret = NULL; 235 236 if ((ret = sshauthopt_new()) == NULL) 237 return NULL; 238 239 /* Defaults for authorized_keys flags */ 240 ret->permit_port_forwarding_flag = 1; 241 ret->permit_agent_forwarding_flag = 1; 242 ret->permit_x11_forwarding_flag = 1; 243 ret->permit_pty_flag = 1; 244 ret->permit_user_rc = 1; 245 return ret; 246 } 247 248 /* 249 * Parse and record a permitopen/permitlisten directive. 250 * Return 0 on success. Return -1 on failure and sets *errstrp to error reason. 251 */ 252 static int 253 handle_permit(const char **optsp, int allow_bare_port, 254 char ***permitsp, size_t *npermitsp, const char **errstrp) 255 { 256 char *opt, *tmp, *cp, *host, **permits = *permitsp; 257 size_t npermits = *npermitsp; 258 const char *errstr = "unknown error"; 259 260 if (npermits > SSH_AUTHOPT_PERMIT_MAX) { 261 *errstrp = "too many permission directives"; 262 return -1; 263 } 264 if ((opt = opt_dequote(optsp, &errstr)) == NULL) { 265 return -1; 266 } 267 if (allow_bare_port && strchr(opt, ':') == NULL) { 268 /* 269 * Allow a bare port number in permitlisten to indicate a 270 * listen_host wildcard. 271 */ 272 if (asprintf(&tmp, "*:%s", opt) == -1) { 273 free(opt); 274 *errstrp = "memory allocation failed"; 275 return -1; 276 } 277 free(opt); 278 opt = tmp; 279 } 280 if ((tmp = strdup(opt)) == NULL) { 281 free(opt); 282 *errstrp = "memory allocation failed"; 283 return -1; 284 } 285 cp = tmp; 286 /* validate syntax before recording it. */ 287 host = hpdelim2(&cp, NULL); 288 if (host == NULL || strlen(host) >= NI_MAXHOST) { 289 free(tmp); 290 free(opt); 291 *errstrp = "invalid permission hostname"; 292 return -1; 293 } 294 /* 295 * don't want to use permitopen_port to avoid 296 * dependency on channels.[ch] here. 297 */ 298 if (cp == NULL || 299 (strcmp(cp, "*") != 0 && a2port(cp) <= 0)) { 300 free(tmp); 301 free(opt); 302 *errstrp = "invalid permission port"; 303 return -1; 304 } 305 /* XXX - add streamlocal support */ 306 free(tmp); 307 /* Record it */ 308 if ((permits = recallocarray(permits, npermits, npermits + 1, 309 sizeof(*permits))) == NULL) { 310 free(opt); 311 /* NB. don't update *permitsp if alloc fails */ 312 *errstrp = "memory allocation failed"; 313 return -1; 314 } 315 permits[npermits++] = opt; 316 *permitsp = permits; 317 *npermitsp = npermits; 318 return 0; 319 } 320 321 struct sshauthopt * 322 sshauthopt_parse(const char *opts, const char **errstrp) 323 { 324 char **oarray, *opt, *cp, *tmp; 325 int r; 326 struct sshauthopt *ret = NULL; 327 const char *errstr = "unknown error"; 328 uint64_t valid_before; 329 size_t i, l; 330 331 if (errstrp != NULL) 332 *errstrp = NULL; 333 if ((ret = sshauthopt_new_with_keys_defaults()) == NULL) 334 goto alloc_fail; 335 336 if (opts == NULL) 337 return ret; 338 339 while (*opts && *opts != ' ' && *opts != '\t') { 340 /* flag options */ 341 if ((r = opt_flag("restrict", 0, &opts)) != -1) { 342 ret->restricted = 1; 343 ret->permit_port_forwarding_flag = 0; 344 ret->permit_agent_forwarding_flag = 0; 345 ret->permit_x11_forwarding_flag = 0; 346 ret->permit_pty_flag = 0; 347 ret->permit_user_rc = 0; 348 } else if ((r = opt_flag("cert-authority", 0, &opts)) != -1) { 349 ret->cert_authority = r; 350 } else if ((r = opt_flag("port-forwarding", 1, &opts)) != -1) { 351 ret->permit_port_forwarding_flag = r == 1; 352 } else if ((r = opt_flag("agent-forwarding", 1, &opts)) != -1) { 353 ret->permit_agent_forwarding_flag = r == 1; 354 } else if ((r = opt_flag("x11-forwarding", 1, &opts)) != -1) { 355 ret->permit_x11_forwarding_flag = r == 1; 356 } else if ((r = opt_flag("touch-required", 1, &opts)) != -1) { 357 ret->no_require_user_presence = r != 1; /* NB. flip */ 358 } else if ((r = opt_flag("verify-required", 1, &opts)) != -1) { 359 ret->require_verify = r == 1; 360 } else if ((r = opt_flag("pty", 1, &opts)) != -1) { 361 ret->permit_pty_flag = r == 1; 362 } else if ((r = opt_flag("user-rc", 1, &opts)) != -1) { 363 ret->permit_user_rc = r == 1; 364 } else if (opt_match(&opts, "command")) { 365 if (ret->force_command != NULL) { 366 errstr = "multiple \"command\" clauses"; 367 goto fail; 368 } 369 ret->force_command = opt_dequote(&opts, &errstr); 370 if (ret->force_command == NULL) 371 goto fail; 372 } else if (opt_match(&opts, "principals")) { 373 if (ret->cert_principals != NULL) { 374 errstr = "multiple \"principals\" clauses"; 375 goto fail; 376 } 377 ret->cert_principals = opt_dequote(&opts, &errstr); 378 if (ret->cert_principals == NULL) 379 goto fail; 380 } else if (opt_match(&opts, "from")) { 381 if (ret->required_from_host_keys != NULL) { 382 errstr = "multiple \"from\" clauses"; 383 goto fail; 384 } 385 ret->required_from_host_keys = opt_dequote(&opts, 386 &errstr); 387 if (ret->required_from_host_keys == NULL) 388 goto fail; 389 } else if (opt_match(&opts, "expiry-time")) { 390 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 391 goto fail; 392 if (parse_absolute_time(opt, &valid_before) != 0 || 393 valid_before == 0) { 394 free(opt); 395 errstr = "invalid expires time"; 396 goto fail; 397 } 398 free(opt); 399 if (ret->valid_before == 0 || 400 valid_before < ret->valid_before) 401 ret->valid_before = valid_before; 402 } else if (opt_match(&opts, "environment")) { 403 if (ret->nenv > SSH_AUTHOPT_ENV_MAX) { 404 errstr = "too many environment strings"; 405 goto fail; 406 } 407 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 408 goto fail; 409 /* env name must be alphanumeric and followed by '=' */ 410 if ((tmp = strchr(opt, '=')) == NULL) { 411 free(opt); 412 errstr = "invalid environment string"; 413 goto fail; 414 } 415 if ((cp = strdup(opt)) == NULL) { 416 free(opt); 417 goto alloc_fail; 418 } 419 l = (size_t)(tmp - opt); 420 cp[l] = '\0'; /* truncate at '=' */ 421 if (!valid_env_name(cp)) { 422 free(cp); 423 free(opt); 424 errstr = "invalid environment string"; 425 goto fail; 426 } 427 /* Check for duplicates; XXX O(n*log(n)) */ 428 for (i = 0; i < ret->nenv; i++) { 429 if (strncmp(ret->env[i], cp, l) == 0 && 430 ret->env[i][l] == '=') 431 break; 432 } 433 free(cp); 434 /* First match wins */ 435 if (i >= ret->nenv) { 436 /* Append it. */ 437 oarray = ret->env; 438 if ((ret->env = recallocarray(ret->env, 439 ret->nenv, ret->nenv + 1, 440 sizeof(*ret->env))) == NULL) { 441 free(opt); 442 /* put it back for cleanup */ 443 ret->env = oarray; 444 goto alloc_fail; 445 } 446 ret->env[ret->nenv++] = opt; 447 opt = NULL; /* transferred */ 448 } 449 free(opt); 450 } else if (opt_match(&opts, "permitopen")) { 451 if (handle_permit(&opts, 0, &ret->permitopen, 452 &ret->npermitopen, &errstr) != 0) 453 goto fail; 454 } else if (opt_match(&opts, "permitlisten")) { 455 if (handle_permit(&opts, 1, &ret->permitlisten, 456 &ret->npermitlisten, &errstr) != 0) 457 goto fail; 458 } else if (opt_match(&opts, "tunnel")) { 459 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 460 goto fail; 461 ret->force_tun_device = a2tun(opt, NULL); 462 free(opt); 463 if (ret->force_tun_device == SSH_TUNID_ERR) { 464 errstr = "invalid tun device"; 465 goto fail; 466 } 467 } 468 /* 469 * Skip the comma, and move to the next option 470 * (or break out if there are no more). 471 */ 472 if (*opts == '\0' || *opts == ' ' || *opts == '\t') 473 break; /* End of options. */ 474 /* Anything other than a comma is an unknown option */ 475 if (*opts != ',') { 476 errstr = "unknown key option"; 477 goto fail; 478 } 479 opts++; 480 if (*opts == '\0') { 481 errstr = "unexpected end-of-options"; 482 goto fail; 483 } 484 } 485 486 /* success */ 487 if (errstrp != NULL) 488 *errstrp = NULL; 489 return ret; 490 491 alloc_fail: 492 errstr = "memory allocation failed"; 493 fail: 494 sshauthopt_free(ret); 495 if (errstrp != NULL) 496 *errstrp = errstr; 497 return NULL; 498 } 499 500 struct sshauthopt * 501 sshauthopt_from_cert(struct sshkey *k) 502 { 503 struct sshauthopt *ret; 504 505 if (k == NULL || !sshkey_type_is_cert(k->type) || k->cert == NULL || 506 k->cert->type != SSH2_CERT_TYPE_USER) 507 return NULL; 508 509 if ((ret = sshauthopt_new()) == NULL) 510 return NULL; 511 512 /* Handle options and critical extensions separately */ 513 if (cert_option_list(ret, k->cert->critical, 514 OPTIONS_CRITICAL, 1) == -1) { 515 sshauthopt_free(ret); 516 return NULL; 517 } 518 if (cert_option_list(ret, k->cert->extensions, 519 OPTIONS_EXTENSIONS, 0) == -1) { 520 sshauthopt_free(ret); 521 return NULL; 522 } 523 /* success */ 524 return ret; 525 } 526 527 /* 528 * Merges "additional" options to "primary" and returns the result. 529 * NB. Some options from primary have primacy. 530 */ 531 struct sshauthopt * 532 sshauthopt_merge(const struct sshauthopt *primary, 533 const struct sshauthopt *additional, const char **errstrp) 534 { 535 struct sshauthopt *ret; 536 const char *errstr = "internal error"; 537 const char *tmp; 538 539 if (errstrp != NULL) 540 *errstrp = NULL; 541 542 if ((ret = sshauthopt_new()) == NULL) 543 goto alloc_fail; 544 545 /* cert_authority and cert_principals are cleared in result */ 546 547 /* Prefer access lists from primary. */ 548 /* XXX err is both set and mismatch? */ 549 tmp = primary->required_from_host_cert; 550 if (tmp == NULL) 551 tmp = additional->required_from_host_cert; 552 if (tmp != NULL && (ret->required_from_host_cert = strdup(tmp)) == NULL) 553 goto alloc_fail; 554 tmp = primary->required_from_host_keys; 555 if (tmp == NULL) 556 tmp = additional->required_from_host_keys; 557 if (tmp != NULL && (ret->required_from_host_keys = strdup(tmp)) == NULL) 558 goto alloc_fail; 559 560 /* 561 * force_tun_device, permitopen/permitlisten and environment all 562 * prefer the primary. 563 */ 564 ret->force_tun_device = primary->force_tun_device; 565 if (ret->force_tun_device == -1) 566 ret->force_tun_device = additional->force_tun_device; 567 if (primary->nenv > 0) { 568 if (dup_strings(&ret->env, &ret->nenv, 569 primary->env, primary->nenv) != 0) 570 goto alloc_fail; 571 } else if (additional->nenv) { 572 if (dup_strings(&ret->env, &ret->nenv, 573 additional->env, additional->nenv) != 0) 574 goto alloc_fail; 575 } 576 if (primary->npermitopen > 0) { 577 if (dup_strings(&ret->permitopen, &ret->npermitopen, 578 primary->permitopen, primary->npermitopen) != 0) 579 goto alloc_fail; 580 } else if (additional->npermitopen > 0) { 581 if (dup_strings(&ret->permitopen, &ret->npermitopen, 582 additional->permitopen, additional->npermitopen) != 0) 583 goto alloc_fail; 584 } 585 586 if (primary->npermitlisten > 0) { 587 if (dup_strings(&ret->permitlisten, &ret->npermitlisten, 588 primary->permitlisten, primary->npermitlisten) != 0) 589 goto alloc_fail; 590 } else if (additional->npermitlisten > 0) { 591 if (dup_strings(&ret->permitlisten, &ret->npermitlisten, 592 additional->permitlisten, additional->npermitlisten) != 0) 593 goto alloc_fail; 594 } 595 596 #define OPTFLAG_AND(x) ret->x = (primary->x == 1) && (additional->x == 1) 597 #define OPTFLAG_OR(x) ret->x = (primary->x == 1) || (additional->x == 1) 598 /* Permissive flags are logical-AND (i.e. must be set in both) */ 599 OPTFLAG_AND(permit_port_forwarding_flag); 600 OPTFLAG_AND(permit_agent_forwarding_flag); 601 OPTFLAG_AND(permit_x11_forwarding_flag); 602 OPTFLAG_AND(permit_pty_flag); 603 OPTFLAG_AND(permit_user_rc); 604 OPTFLAG_AND(no_require_user_presence); 605 /* Restrictive flags are logical-OR (i.e. must be set in either) */ 606 OPTFLAG_OR(require_verify); 607 #undef OPTFLAG_AND 608 609 /* Earliest expiry time should win */ 610 if (primary->valid_before != 0) 611 ret->valid_before = primary->valid_before; 612 if (additional->valid_before != 0 && 613 additional->valid_before < ret->valid_before) 614 ret->valid_before = additional->valid_before; 615 616 /* 617 * When both multiple forced-command are specified, only 618 * proceed if they are identical, otherwise fail. 619 */ 620 if (primary->force_command != NULL && 621 additional->force_command != NULL) { 622 if (strcmp(primary->force_command, 623 additional->force_command) == 0) { 624 /* ok */ 625 ret->force_command = strdup(primary->force_command); 626 if (ret->force_command == NULL) 627 goto alloc_fail; 628 } else { 629 errstr = "forced command options do not match"; 630 goto fail; 631 } 632 } else if (primary->force_command != NULL) { 633 if ((ret->force_command = strdup( 634 primary->force_command)) == NULL) 635 goto alloc_fail; 636 } else if (additional->force_command != NULL) { 637 if ((ret->force_command = strdup( 638 additional->force_command)) == NULL) 639 goto alloc_fail; 640 } 641 /* success */ 642 if (errstrp != NULL) 643 *errstrp = NULL; 644 return ret; 645 646 alloc_fail: 647 errstr = "memory allocation failed"; 648 fail: 649 if (errstrp != NULL) 650 *errstrp = errstr; 651 sshauthopt_free(ret); 652 return NULL; 653 } 654 655 /* 656 * Copy options 657 */ 658 struct sshauthopt * 659 sshauthopt_copy(const struct sshauthopt *orig) 660 { 661 struct sshauthopt *ret; 662 663 if ((ret = sshauthopt_new()) == NULL) 664 return NULL; 665 666 #define OPTSCALAR(x) ret->x = orig->x 667 OPTSCALAR(permit_port_forwarding_flag); 668 OPTSCALAR(permit_agent_forwarding_flag); 669 OPTSCALAR(permit_x11_forwarding_flag); 670 OPTSCALAR(permit_pty_flag); 671 OPTSCALAR(permit_user_rc); 672 OPTSCALAR(restricted); 673 OPTSCALAR(cert_authority); 674 OPTSCALAR(force_tun_device); 675 OPTSCALAR(valid_before); 676 OPTSCALAR(no_require_user_presence); 677 OPTSCALAR(require_verify); 678 #undef OPTSCALAR 679 #define OPTSTRING(x) \ 680 do { \ 681 if (orig->x != NULL && (ret->x = strdup(orig->x)) == NULL) { \ 682 sshauthopt_free(ret); \ 683 return NULL; \ 684 } \ 685 } while (0) 686 OPTSTRING(cert_principals); 687 OPTSTRING(force_command); 688 OPTSTRING(required_from_host_cert); 689 OPTSTRING(required_from_host_keys); 690 #undef OPTSTRING 691 692 if (dup_strings(&ret->env, &ret->nenv, orig->env, orig->nenv) != 0 || 693 dup_strings(&ret->permitopen, &ret->npermitopen, 694 orig->permitopen, orig->npermitopen) != 0 || 695 dup_strings(&ret->permitlisten, &ret->npermitlisten, 696 orig->permitlisten, orig->npermitlisten) != 0) { 697 sshauthopt_free(ret); 698 return NULL; 699 } 700 return ret; 701 } 702 703 static int 704 serialise_array(struct sshbuf *m, char **a, size_t n) 705 { 706 struct sshbuf *b; 707 size_t i; 708 int r = SSH_ERR_INTERNAL_ERROR; 709 710 if (n > INT_MAX) 711 return SSH_ERR_INTERNAL_ERROR; 712 713 if ((b = sshbuf_new()) == NULL) { 714 return SSH_ERR_ALLOC_FAIL; 715 } 716 for (i = 0; i < n; i++) { 717 if ((r = sshbuf_put_cstring(b, a[i])) != 0) 718 goto out; 719 } 720 if ((r = sshbuf_put_u32(m, n)) != 0 || 721 (r = sshbuf_put_stringb(m, b)) != 0) 722 goto out; 723 /* success */ 724 r = 0; 725 out: 726 sshbuf_free(b); 727 return r; 728 } 729 730 static int 731 deserialise_array(struct sshbuf *m, char ***ap, size_t *np) 732 { 733 char **a = NULL; 734 size_t i, n = 0; 735 struct sshbuf *b = NULL; 736 u_int tmp; 737 int r = SSH_ERR_INTERNAL_ERROR; 738 739 if ((r = sshbuf_get_u32(m, &tmp)) != 0 || 740 (r = sshbuf_froms(m, &b)) != 0) 741 goto out; 742 if (tmp > INT_MAX) { 743 r = SSH_ERR_INVALID_FORMAT; 744 goto out; 745 } 746 n = tmp; 747 if (n > 0 && (a = calloc(n, sizeof(*a))) == NULL) { 748 r = SSH_ERR_ALLOC_FAIL; 749 goto out; 750 } 751 for (i = 0; i < n; i++) { 752 if ((r = sshbuf_get_cstring(b, &a[i], NULL)) != 0) 753 goto out; 754 } 755 /* success */ 756 r = 0; 757 *ap = a; 758 a = NULL; 759 *np = n; 760 n = 0; 761 out: 762 if (a != NULL) { 763 for (i = 0; i < n; i++) 764 free(a[i]); 765 free(a); 766 } 767 sshbuf_free(b); 768 return r; 769 } 770 771 static int 772 serialise_nullable_string(struct sshbuf *m, const char *s) 773 { 774 int r; 775 776 if ((r = sshbuf_put_u8(m, s == NULL)) != 0 || 777 (r = sshbuf_put_cstring(m, s)) != 0) 778 return r; 779 return 0; 780 } 781 782 static int 783 deserialise_nullable_string(struct sshbuf *m, char **sp) 784 { 785 int r; 786 u_char flag; 787 788 *sp = NULL; 789 if ((r = sshbuf_get_u8(m, &flag)) != 0 || 790 (r = sshbuf_get_cstring(m, flag ? NULL : sp, NULL)) != 0) 791 return r; 792 return 0; 793 } 794 795 int 796 sshauthopt_serialise(const struct sshauthopt *opts, struct sshbuf *m, 797 int untrusted) 798 { 799 int r = SSH_ERR_INTERNAL_ERROR; 800 801 /* Flag options */ 802 if ((r = sshbuf_put_u8(m, opts->permit_port_forwarding_flag)) != 0 || 803 (r = sshbuf_put_u8(m, opts->permit_agent_forwarding_flag)) != 0 || 804 (r = sshbuf_put_u8(m, opts->permit_x11_forwarding_flag)) != 0 || 805 (r = sshbuf_put_u8(m, opts->permit_pty_flag)) != 0 || 806 (r = sshbuf_put_u8(m, opts->permit_user_rc)) != 0 || 807 (r = sshbuf_put_u8(m, opts->restricted)) != 0 || 808 (r = sshbuf_put_u8(m, opts->cert_authority)) != 0 || 809 (r = sshbuf_put_u8(m, opts->no_require_user_presence)) != 0 || 810 (r = sshbuf_put_u8(m, opts->require_verify)) != 0) 811 return r; 812 813 /* Simple integer options */ 814 if ((r = sshbuf_put_u64(m, opts->valid_before)) != 0) 815 return r; 816 817 /* tunnel number can be negative to indicate "unset" */ 818 if ((r = sshbuf_put_u8(m, opts->force_tun_device == -1)) != 0 || 819 (r = sshbuf_put_u32(m, (opts->force_tun_device < 0) ? 820 0 : (u_int)opts->force_tun_device)) != 0) 821 return r; 822 823 /* String options; these may be NULL */ 824 if ((r = serialise_nullable_string(m, 825 untrusted ? "yes" : opts->cert_principals)) != 0 || 826 (r = serialise_nullable_string(m, 827 untrusted ? "true" : opts->force_command)) != 0 || 828 (r = serialise_nullable_string(m, 829 untrusted ? NULL : opts->required_from_host_cert)) != 0 || 830 (r = serialise_nullable_string(m, 831 untrusted ? NULL : opts->required_from_host_keys)) != 0) 832 return r; 833 834 /* Array options */ 835 if ((r = serialise_array(m, opts->env, 836 untrusted ? 0 : opts->nenv)) != 0 || 837 (r = serialise_array(m, opts->permitopen, 838 untrusted ? 0 : opts->npermitopen)) != 0 || 839 (r = serialise_array(m, opts->permitlisten, 840 untrusted ? 0 : opts->npermitlisten)) != 0) 841 return r; 842 843 /* success */ 844 return 0; 845 } 846 847 int 848 sshauthopt_deserialise(struct sshbuf *m, struct sshauthopt **optsp) 849 { 850 struct sshauthopt *opts = NULL; 851 int r = SSH_ERR_INTERNAL_ERROR; 852 u_char f; 853 u_int tmp; 854 855 if ((opts = calloc(1, sizeof(*opts))) == NULL) 856 return SSH_ERR_ALLOC_FAIL; 857 858 /* Flag options */ 859 #define OPT_FLAG(x) \ 860 do { \ 861 if ((r = sshbuf_get_u8(m, &f)) != 0) \ 862 goto out; \ 863 opts->x = f; \ 864 } while (0) 865 OPT_FLAG(permit_port_forwarding_flag); 866 OPT_FLAG(permit_agent_forwarding_flag); 867 OPT_FLAG(permit_x11_forwarding_flag); 868 OPT_FLAG(permit_pty_flag); 869 OPT_FLAG(permit_user_rc); 870 OPT_FLAG(restricted); 871 OPT_FLAG(cert_authority); 872 OPT_FLAG(no_require_user_presence); 873 OPT_FLAG(require_verify); 874 #undef OPT_FLAG 875 876 /* Simple integer options */ 877 if ((r = sshbuf_get_u64(m, &opts->valid_before)) != 0) 878 goto out; 879 880 /* tunnel number can be negative to indicate "unset" */ 881 if ((r = sshbuf_get_u8(m, &f)) != 0 || 882 (r = sshbuf_get_u32(m, &tmp)) != 0) 883 goto out; 884 opts->force_tun_device = f ? -1 : (int)tmp; 885 886 /* String options may be NULL */ 887 if ((r = deserialise_nullable_string(m, &opts->cert_principals)) != 0 || 888 (r = deserialise_nullable_string(m, &opts->force_command)) != 0 || 889 (r = deserialise_nullable_string(m, 890 &opts->required_from_host_cert)) != 0 || 891 (r = deserialise_nullable_string(m, 892 &opts->required_from_host_keys)) != 0) 893 goto out; 894 895 /* Array options */ 896 if ((r = deserialise_array(m, &opts->env, &opts->nenv)) != 0 || 897 (r = deserialise_array(m, 898 &opts->permitopen, &opts->npermitopen)) != 0 || 899 (r = deserialise_array(m, 900 &opts->permitlisten, &opts->npermitlisten)) != 0) 901 goto out; 902 903 /* success */ 904 r = 0; 905 *optsp = opts; 906 opts = NULL; 907 out: 908 sshauthopt_free(opts); 909 return r; 910 } 911