1 /* $NetBSD: auth-options.c,v 1.28 2022/02/23 19:07:20 christos Exp $ */ 2 /* $OpenBSD: auth-options.c,v 1.98 2022/02/08 08:59:12 dtucker Exp $ */ 3 /* 4 * Copyright (c) 2018 Damien Miller <djm@mindrot.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include "includes.h" 20 __RCSID("$NetBSD: auth-options.c,v 1.28 2022/02/23 19:07:20 christos Exp $"); 21 #include <sys/types.h> 22 #include <sys/queue.h> 23 24 #include <stdlib.h> 25 #include <netdb.h> 26 #include <pwd.h> 27 #include <string.h> 28 #include <stdio.h> 29 #include <stdarg.h> 30 #include <time.h> 31 #include <ctype.h> 32 #include <limits.h> 33 34 #include "xmalloc.h" 35 #include "ssherr.h" 36 #include "log.h" 37 #include "sshbuf.h" 38 #include "misc.h" 39 #include "sshkey.h" 40 #include "match.h" 41 #include "ssh2.h" 42 #include "auth-options.h" 43 44 static int 45 dup_strings(char ***dstp, size_t *ndstp, char **src, size_t nsrc) 46 { 47 char **dst; 48 size_t i, j; 49 50 *dstp = NULL; 51 *ndstp = 0; 52 if (nsrc == 0) 53 return 0; 54 55 if ((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 goto out; 158 } 159 opts->required_from_host_cert = allowed; 160 found = 1; 161 } 162 } 163 164 if (!found) { 165 if (crit) { 166 error("Certificate critical option \"%s\" " 167 "is not supported", name); 168 goto out; 169 } else { 170 logit("Certificate extension \"%s\" " 171 "is not supported", name); 172 } 173 } else if (sshbuf_len(data) != 0) { 174 error("Certificate option \"%s\" corrupt " 175 "(extra data)", name); 176 goto out; 177 } 178 free(name); 179 name = NULL; 180 } 181 /* successfully parsed all options */ 182 ret = 0; 183 184 out: 185 free(name); 186 sshbuf_free(data); 187 sshbuf_free(c); 188 return ret; 189 } 190 191 struct sshauthopt * 192 sshauthopt_new(void) 193 { 194 struct sshauthopt *ret; 195 196 if ((ret = calloc(1, sizeof(*ret))) == NULL) 197 return NULL; 198 ret->force_tun_device = -1; 199 return ret; 200 } 201 202 void 203 sshauthopt_free(struct sshauthopt *opts) 204 { 205 size_t i; 206 207 if (opts == NULL) 208 return; 209 210 free(opts->cert_principals); 211 free(opts->force_command); 212 free(opts->required_from_host_cert); 213 free(opts->required_from_host_keys); 214 215 for (i = 0; i < opts->nenv; i++) 216 free(opts->env[i]); 217 free(opts->env); 218 219 for (i = 0; i < opts->npermitopen; i++) 220 free(opts->permitopen[i]); 221 free(opts->permitopen); 222 223 for (i = 0; i < opts->npermitlisten; i++) 224 free(opts->permitlisten[i]); 225 free(opts->permitlisten); 226 227 freezero(opts, sizeof(*opts)); 228 } 229 230 struct sshauthopt * 231 sshauthopt_new_with_keys_defaults(void) 232 { 233 struct sshauthopt *ret = NULL; 234 235 if ((ret = sshauthopt_new()) == NULL) 236 return NULL; 237 238 /* Defaults for authorized_keys flags */ 239 ret->permit_port_forwarding_flag = 1; 240 ret->permit_agent_forwarding_flag = 1; 241 ret->permit_x11_forwarding_flag = 1; 242 ret->permit_pty_flag = 1; 243 ret->permit_user_rc = 1; 244 return ret; 245 } 246 247 /* 248 * Parse and record a permitopen/permitlisten directive. 249 * Return 0 on success. Return -1 on failure and sets *errstrp to error reason. 250 */ 251 static int 252 handle_permit(const char **optsp, int allow_bare_port, 253 char ***permitsp, size_t *npermitsp, const char **errstrp) 254 { 255 char *opt, *tmp, *cp, *host, **permits = *permitsp; 256 size_t npermits = *npermitsp; 257 const char *errstr = "unknown error"; 258 259 if (npermits > SSH_AUTHOPT_PERMIT_MAX) { 260 *errstrp = "too many permission directives"; 261 return -1; 262 } 263 if ((opt = opt_dequote(optsp, &errstr)) == NULL) { 264 return -1; 265 } 266 if (allow_bare_port && strchr(opt, ':') == NULL) { 267 /* 268 * Allow a bare port number in permitlisten to indicate a 269 * listen_host wildcard. 270 */ 271 if (asprintf(&tmp, "*:%s", opt) == -1) { 272 free(opt); 273 *errstrp = "memory allocation failed"; 274 return -1; 275 } 276 free(opt); 277 opt = tmp; 278 } 279 if ((tmp = strdup(opt)) == NULL) { 280 free(opt); 281 *errstrp = "memory allocation failed"; 282 return -1; 283 } 284 cp = tmp; 285 /* validate syntax before recording it. */ 286 host = hpdelim2(&cp, NULL); 287 if (host == NULL || strlen(host) >= NI_MAXHOST) { 288 free(tmp); 289 free(opt); 290 *errstrp = "invalid permission hostname"; 291 return -1; 292 } 293 /* 294 * don't want to use permitopen_port to avoid 295 * dependency on channels.[ch] here. 296 */ 297 if (cp == NULL || 298 (strcmp(cp, "*") != 0 && a2port(cp) <= 0)) { 299 free(tmp); 300 free(opt); 301 *errstrp = "invalid permission port"; 302 return -1; 303 } 304 /* XXX - add streamlocal support */ 305 free(tmp); 306 /* Record it */ 307 if ((permits = recallocarray(permits, npermits, npermits + 1, 308 sizeof(*permits))) == NULL) { 309 free(opt); 310 /* NB. don't update *permitsp if alloc fails */ 311 *errstrp = "memory allocation failed"; 312 return -1; 313 } 314 permits[npermits++] = opt; 315 *permitsp = permits; 316 *npermitsp = npermits; 317 return 0; 318 } 319 320 struct sshauthopt * 321 sshauthopt_parse(const char *opts, const char **errstrp) 322 { 323 char **oarray, *opt, *cp, *tmp; 324 int r; 325 struct sshauthopt *ret = NULL; 326 const char *errstr = "unknown error"; 327 uint64_t valid_before; 328 size_t i, l; 329 330 if (errstrp != NULL) 331 *errstrp = NULL; 332 if ((ret = sshauthopt_new_with_keys_defaults()) == NULL) 333 goto alloc_fail; 334 335 if (opts == NULL) 336 return ret; 337 338 while (*opts && *opts != ' ' && *opts != '\t') { 339 /* flag options */ 340 if ((r = opt_flag("restrict", 0, &opts)) != -1) { 341 ret->restricted = 1; 342 ret->permit_port_forwarding_flag = 0; 343 ret->permit_agent_forwarding_flag = 0; 344 ret->permit_x11_forwarding_flag = 0; 345 ret->permit_pty_flag = 0; 346 ret->permit_user_rc = 0; 347 } else if ((r = opt_flag("cert-authority", 0, &opts)) != -1) { 348 ret->cert_authority = r; 349 } else if ((r = opt_flag("port-forwarding", 1, &opts)) != -1) { 350 ret->permit_port_forwarding_flag = r == 1; 351 } else if ((r = opt_flag("agent-forwarding", 1, &opts)) != -1) { 352 ret->permit_agent_forwarding_flag = r == 1; 353 } else if ((r = opt_flag("x11-forwarding", 1, &opts)) != -1) { 354 ret->permit_x11_forwarding_flag = r == 1; 355 } else if ((r = opt_flag("touch-required", 1, &opts)) != -1) { 356 ret->no_require_user_presence = r != 1; /* NB. flip */ 357 } else if ((r = opt_flag("verify-required", 1, &opts)) != -1) { 358 ret->require_verify = r == 1; 359 } else if ((r = opt_flag("pty", 1, &opts)) != -1) { 360 ret->permit_pty_flag = r == 1; 361 } else if ((r = opt_flag("user-rc", 1, &opts)) != -1) { 362 ret->permit_user_rc = r == 1; 363 } else if (opt_match(&opts, "command")) { 364 if (ret->force_command != NULL) { 365 errstr = "multiple \"command\" clauses"; 366 goto fail; 367 } 368 ret->force_command = opt_dequote(&opts, &errstr); 369 if (ret->force_command == NULL) 370 goto fail; 371 } else if (opt_match(&opts, "principals")) { 372 if (ret->cert_principals != NULL) { 373 errstr = "multiple \"principals\" clauses"; 374 goto fail; 375 } 376 ret->cert_principals = opt_dequote(&opts, &errstr); 377 if (ret->cert_principals == NULL) 378 goto fail; 379 } else if (opt_match(&opts, "from")) { 380 if (ret->required_from_host_keys != NULL) { 381 errstr = "multiple \"from\" clauses"; 382 goto fail; 383 } 384 ret->required_from_host_keys = opt_dequote(&opts, 385 &errstr); 386 if (ret->required_from_host_keys == NULL) 387 goto fail; 388 } else if (opt_match(&opts, "expiry-time")) { 389 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 390 goto fail; 391 if (parse_absolute_time(opt, &valid_before) != 0 || 392 valid_before == 0) { 393 free(opt); 394 errstr = "invalid expires time"; 395 goto fail; 396 } 397 free(opt); 398 if (ret->valid_before == 0 || 399 valid_before < ret->valid_before) 400 ret->valid_before = valid_before; 401 } else if (opt_match(&opts, "environment")) { 402 if (ret->nenv > SSH_AUTHOPT_ENV_MAX) { 403 errstr = "too many environment strings"; 404 goto fail; 405 } 406 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 407 goto fail; 408 /* env name must be alphanumeric and followed by '=' */ 409 if ((tmp = strchr(opt, '=')) == NULL) { 410 free(opt); 411 errstr = "invalid environment string"; 412 goto fail; 413 } 414 if ((cp = strdup(opt)) == NULL) { 415 free(opt); 416 goto alloc_fail; 417 } 418 l = (size_t)(tmp - opt); 419 cp[l] = '\0'; /* truncate at '=' */ 420 if (!valid_env_name(cp)) { 421 free(cp); 422 free(opt); 423 errstr = "invalid environment string"; 424 goto fail; 425 } 426 /* Check for duplicates; XXX O(n*log(n)) */ 427 for (i = 0; i < ret->nenv; i++) { 428 if (strncmp(ret->env[i], cp, l) == 0 && 429 ret->env[i][l] == '=') 430 break; 431 } 432 free(cp); 433 /* First match wins */ 434 if (i >= ret->nenv) { 435 /* Append it. */ 436 oarray = ret->env; 437 if ((ret->env = recallocarray(ret->env, 438 ret->nenv, ret->nenv + 1, 439 sizeof(*ret->env))) == NULL) { 440 free(opt); 441 /* put it back for cleanup */ 442 ret->env = oarray; 443 goto alloc_fail; 444 } 445 ret->env[ret->nenv++] = opt; 446 opt = NULL; /* transferred */ 447 } 448 free(opt); 449 } else if (opt_match(&opts, "permitopen")) { 450 if (handle_permit(&opts, 0, &ret->permitopen, 451 &ret->npermitopen, &errstr) != 0) 452 goto fail; 453 } else if (opt_match(&opts, "permitlisten")) { 454 if (handle_permit(&opts, 1, &ret->permitlisten, 455 &ret->npermitlisten, &errstr) != 0) 456 goto fail; 457 } else if (opt_match(&opts, "tunnel")) { 458 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 459 goto fail; 460 ret->force_tun_device = a2tun(opt, NULL); 461 free(opt); 462 if (ret->force_tun_device == SSH_TUNID_ERR) { 463 errstr = "invalid tun device"; 464 goto fail; 465 } 466 } 467 /* 468 * Skip the comma, and move to the next option 469 * (or break out if there are no more). 470 */ 471 if (*opts == '\0' || *opts == ' ' || *opts == '\t') 472 break; /* End of options. */ 473 /* Anything other than a comma is an unknown option */ 474 if (*opts != ',') { 475 errstr = "unknown key option"; 476 goto fail; 477 } 478 opts++; 479 if (*opts == '\0') { 480 errstr = "unexpected end-of-options"; 481 goto fail; 482 } 483 } 484 485 /* success */ 486 if (errstrp != NULL) 487 *errstrp = NULL; 488 return ret; 489 490 alloc_fail: 491 errstr = "memory allocation failed"; 492 fail: 493 sshauthopt_free(ret); 494 if (errstrp != NULL) 495 *errstrp = errstr; 496 return NULL; 497 } 498 499 struct sshauthopt * 500 sshauthopt_from_cert(struct sshkey *k) 501 { 502 struct sshauthopt *ret; 503 504 if (k == NULL || !sshkey_type_is_cert(k->type) || k->cert == NULL || 505 k->cert->type != SSH2_CERT_TYPE_USER) 506 return NULL; 507 508 if ((ret = sshauthopt_new()) == NULL) 509 return NULL; 510 511 /* Handle options and critical extensions separately */ 512 if (cert_option_list(ret, k->cert->critical, 513 OPTIONS_CRITICAL, 1) == -1) { 514 sshauthopt_free(ret); 515 return NULL; 516 } 517 if (cert_option_list(ret, k->cert->extensions, 518 OPTIONS_EXTENSIONS, 0) == -1) { 519 sshauthopt_free(ret); 520 return NULL; 521 } 522 /* success */ 523 return ret; 524 } 525 526 /* 527 * Merges "additional" options to "primary" and returns the result. 528 * NB. Some options from primary have primacy. 529 */ 530 struct sshauthopt * 531 sshauthopt_merge(const struct sshauthopt *primary, 532 const struct sshauthopt *additional, const char **errstrp) 533 { 534 struct sshauthopt *ret; 535 const char *errstr = "internal error"; 536 const char *tmp; 537 538 if (errstrp != NULL) 539 *errstrp = NULL; 540 541 if ((ret = sshauthopt_new()) == NULL) 542 goto alloc_fail; 543 544 /* cert_authority and cert_principals are cleared in result */ 545 546 /* Prefer access lists from primary. */ 547 /* XXX err is both set and mismatch? */ 548 tmp = primary->required_from_host_cert; 549 if (tmp == NULL) 550 tmp = additional->required_from_host_cert; 551 if (tmp != NULL && (ret->required_from_host_cert = strdup(tmp)) == NULL) 552 goto alloc_fail; 553 tmp = primary->required_from_host_keys; 554 if (tmp == NULL) 555 tmp = additional->required_from_host_keys; 556 if (tmp != NULL && (ret->required_from_host_keys = strdup(tmp)) == NULL) 557 goto alloc_fail; 558 559 /* 560 * force_tun_device, permitopen/permitlisten and environment all 561 * prefer the primary. 562 */ 563 ret->force_tun_device = primary->force_tun_device; 564 if (ret->force_tun_device == -1) 565 ret->force_tun_device = additional->force_tun_device; 566 if (primary->nenv > 0) { 567 if (dup_strings(&ret->env, &ret->nenv, 568 primary->env, primary->nenv) != 0) 569 goto alloc_fail; 570 } else if (additional->nenv) { 571 if (dup_strings(&ret->env, &ret->nenv, 572 additional->env, additional->nenv) != 0) 573 goto alloc_fail; 574 } 575 if (primary->npermitopen > 0) { 576 if (dup_strings(&ret->permitopen, &ret->npermitopen, 577 primary->permitopen, primary->npermitopen) != 0) 578 goto alloc_fail; 579 } else if (additional->npermitopen > 0) { 580 if (dup_strings(&ret->permitopen, &ret->npermitopen, 581 additional->permitopen, additional->npermitopen) != 0) 582 goto alloc_fail; 583 } 584 585 if (primary->npermitlisten > 0) { 586 if (dup_strings(&ret->permitlisten, &ret->npermitlisten, 587 primary->permitlisten, primary->npermitlisten) != 0) 588 goto alloc_fail; 589 } else if (additional->npermitlisten > 0) { 590 if (dup_strings(&ret->permitlisten, &ret->npermitlisten, 591 additional->permitlisten, additional->npermitlisten) != 0) 592 goto alloc_fail; 593 } 594 595 #define OPTFLAG_AND(x) ret->x = (primary->x == 1) && (additional->x == 1) 596 #define OPTFLAG_OR(x) ret->x = (primary->x == 1) || (additional->x == 1) 597 /* Permissive flags are logical-AND (i.e. must be set in both) */ 598 OPTFLAG_AND(permit_port_forwarding_flag); 599 OPTFLAG_AND(permit_agent_forwarding_flag); 600 OPTFLAG_AND(permit_x11_forwarding_flag); 601 OPTFLAG_AND(permit_pty_flag); 602 OPTFLAG_AND(permit_user_rc); 603 OPTFLAG_AND(no_require_user_presence); 604 /* Restrictive flags are logical-OR (i.e. must be set in either) */ 605 OPTFLAG_OR(require_verify); 606 #undef OPTFLAG_AND 607 608 /* Earliest expiry time should win */ 609 if (primary->valid_before != 0) 610 ret->valid_before = primary->valid_before; 611 if (additional->valid_before != 0 && 612 additional->valid_before < ret->valid_before) 613 ret->valid_before = additional->valid_before; 614 615 /* 616 * When both multiple forced-command are specified, only 617 * proceed if they are identical, otherwise fail. 618 */ 619 if (primary->force_command != NULL && 620 additional->force_command != NULL) { 621 if (strcmp(primary->force_command, 622 additional->force_command) == 0) { 623 /* ok */ 624 ret->force_command = strdup(primary->force_command); 625 if (ret->force_command == NULL) 626 goto alloc_fail; 627 } else { 628 errstr = "forced command options do not match"; 629 goto fail; 630 } 631 } else if (primary->force_command != NULL) { 632 if ((ret->force_command = strdup( 633 primary->force_command)) == NULL) 634 goto alloc_fail; 635 } else if (additional->force_command != NULL) { 636 if ((ret->force_command = strdup( 637 additional->force_command)) == NULL) 638 goto alloc_fail; 639 } 640 /* success */ 641 if (errstrp != NULL) 642 *errstrp = NULL; 643 return ret; 644 645 alloc_fail: 646 errstr = "memory allocation failed"; 647 fail: 648 if (errstrp != NULL) 649 *errstrp = errstr; 650 sshauthopt_free(ret); 651 return NULL; 652 } 653 654 /* 655 * Copy options 656 */ 657 struct sshauthopt * 658 sshauthopt_copy(const struct sshauthopt *orig) 659 { 660 struct sshauthopt *ret; 661 662 if ((ret = sshauthopt_new()) == NULL) 663 return NULL; 664 665 #define OPTSCALAR(x) ret->x = orig->x 666 OPTSCALAR(permit_port_forwarding_flag); 667 OPTSCALAR(permit_agent_forwarding_flag); 668 OPTSCALAR(permit_x11_forwarding_flag); 669 OPTSCALAR(permit_pty_flag); 670 OPTSCALAR(permit_user_rc); 671 OPTSCALAR(restricted); 672 OPTSCALAR(cert_authority); 673 OPTSCALAR(force_tun_device); 674 OPTSCALAR(valid_before); 675 OPTSCALAR(no_require_user_presence); 676 OPTSCALAR(require_verify); 677 #undef OPTSCALAR 678 #define OPTSTRING(x) \ 679 do { \ 680 if (orig->x != NULL && (ret->x = strdup(orig->x)) == NULL) { \ 681 sshauthopt_free(ret); \ 682 return NULL; \ 683 } \ 684 } while (0) 685 OPTSTRING(cert_principals); 686 OPTSTRING(force_command); 687 OPTSTRING(required_from_host_cert); 688 OPTSTRING(required_from_host_keys); 689 #undef OPTSTRING 690 691 if (dup_strings(&ret->env, &ret->nenv, orig->env, orig->nenv) != 0 || 692 dup_strings(&ret->permitopen, &ret->npermitopen, 693 orig->permitopen, orig->npermitopen) != 0 || 694 dup_strings(&ret->permitlisten, &ret->npermitlisten, 695 orig->permitlisten, orig->npermitlisten) != 0) { 696 sshauthopt_free(ret); 697 return NULL; 698 } 699 return ret; 700 } 701 702 static int 703 serialise_array(struct sshbuf *m, char **a, size_t n) 704 { 705 struct sshbuf *b; 706 size_t i; 707 int r; 708 709 if (n > INT_MAX) 710 return SSH_ERR_INTERNAL_ERROR; 711 712 if ((b = sshbuf_new()) == NULL) { 713 return SSH_ERR_ALLOC_FAIL; 714 } 715 for (i = 0; i < n; i++) { 716 if ((r = sshbuf_put_cstring(b, a[i])) != 0) { 717 sshbuf_free(b); 718 return r; 719 } 720 } 721 if ((r = sshbuf_put_u32(m, n)) != 0 || 722 (r = sshbuf_put_stringb(m, b)) != 0) { 723 sshbuf_free(b); 724 return r; 725 } 726 /* success */ 727 return 0; 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