1 /* $OpenBSD: auth-options.c,v 1.101 2023/07/14 07:44:21 dtucker Exp $ */ 2 /* 3 * Copyright (c) 2018 Damien Miller <djm@mindrot.org> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #include "includes.h" 19 20 #include <sys/types.h> 21 22 #include <stdlib.h> 23 #include <netdb.h> 24 #include <pwd.h> 25 #include <string.h> 26 #include <stdio.h> 27 #ifdef HAVE_STDINT_H 28 # include <stdint.h> 29 #endif 30 #include <stdarg.h> 31 #include <ctype.h> 32 #include <limits.h> 33 34 #include "openbsd-compat/sys-queue.h" 35 36 #include "xmalloc.h" 37 #include "ssherr.h" 38 #include "log.h" 39 #include "sshbuf.h" 40 #include "misc.h" 41 #include "sshkey.h" 42 #include "match.h" 43 #include "ssh2.h" 44 #include "auth-options.h" 45 46 static int 47 dup_strings(char ***dstp, size_t *ndstp, char **src, size_t nsrc) 48 { 49 char **dst; 50 size_t i, j; 51 52 *dstp = NULL; 53 *ndstp = 0; 54 55 if (nsrc == 0) 56 return 0; 57 if (nsrc >= SIZE_MAX / sizeof(*src) || 58 (dst = calloc(nsrc, sizeof(*src))) == NULL) 59 return -1; 60 for (i = 0; i < nsrc; i++) { 61 if ((dst[i] = strdup(src[i])) == NULL) { 62 for (j = 0; j < i; j++) 63 free(dst[j]); 64 free(dst); 65 return -1; 66 } 67 } 68 /* success */ 69 *dstp = dst; 70 *ndstp = nsrc; 71 return 0; 72 } 73 74 #define OPTIONS_CRITICAL 1 75 #define OPTIONS_EXTENSIONS 2 76 static int 77 cert_option_list(struct sshauthopt *opts, struct sshbuf *oblob, 78 u_int which, int crit) 79 { 80 char *command, *allowed; 81 char *name = NULL; 82 struct sshbuf *c = NULL, *data = NULL; 83 int r, ret = -1, found; 84 85 if ((c = sshbuf_fromb(oblob)) == NULL) { 86 error_f("sshbuf_fromb failed"); 87 goto out; 88 } 89 90 while (sshbuf_len(c) > 0) { 91 sshbuf_free(data); 92 data = NULL; 93 if ((r = sshbuf_get_cstring(c, &name, NULL)) != 0 || 94 (r = sshbuf_froms(c, &data)) != 0) { 95 error_r(r, "Unable to parse certificate options"); 96 goto out; 97 } 98 debug3("found certificate option \"%.100s\" len %zu", 99 name, sshbuf_len(data)); 100 found = 0; 101 if ((which & OPTIONS_EXTENSIONS) != 0) { 102 if (strcmp(name, "no-touch-required") == 0) { 103 opts->no_require_user_presence = 1; 104 found = 1; 105 } else if (strcmp(name, "permit-X11-forwarding") == 0) { 106 opts->permit_x11_forwarding_flag = 1; 107 found = 1; 108 } else if (strcmp(name, 109 "permit-agent-forwarding") == 0) { 110 opts->permit_agent_forwarding_flag = 1; 111 found = 1; 112 } else if (strcmp(name, 113 "permit-port-forwarding") == 0) { 114 opts->permit_port_forwarding_flag = 1; 115 found = 1; 116 } else if (strcmp(name, "permit-pty") == 0) { 117 opts->permit_pty_flag = 1; 118 found = 1; 119 } else if (strcmp(name, "permit-user-rc") == 0) { 120 opts->permit_user_rc = 1; 121 found = 1; 122 } 123 } 124 if (!found && (which & OPTIONS_CRITICAL) != 0) { 125 if (strcmp(name, "verify-required") == 0) { 126 opts->require_verify = 1; 127 found = 1; 128 } else if (strcmp(name, "force-command") == 0) { 129 if ((r = sshbuf_get_cstring(data, &command, 130 NULL)) != 0) { 131 error_r(r, "Unable to parse \"%s\" " 132 "section", name); 133 goto out; 134 } 135 if (opts->force_command != NULL) { 136 error("Certificate has multiple " 137 "force-command options"); 138 free(command); 139 goto out; 140 } 141 opts->force_command = command; 142 found = 1; 143 } else if (strcmp(name, "source-address") == 0) { 144 if ((r = sshbuf_get_cstring(data, &allowed, 145 NULL)) != 0) { 146 error_r(r, "Unable to parse \"%s\" " 147 "section", name); 148 goto out; 149 } 150 if (opts->required_from_host_cert != NULL) { 151 error("Certificate has multiple " 152 "source-address options"); 153 free(allowed); 154 goto out; 155 } 156 /* Check syntax */ 157 if (addr_match_cidr_list(NULL, allowed) == -1) { 158 error("Certificate source-address " 159 "contents invalid"); 160 goto out; 161 } 162 opts->required_from_host_cert = allowed; 163 found = 1; 164 } 165 } 166 167 if (!found) { 168 if (crit) { 169 error("Certificate critical option \"%s\" " 170 "is not supported", name); 171 goto out; 172 } else { 173 logit("Certificate extension \"%s\" " 174 "is not supported", name); 175 } 176 } else if (sshbuf_len(data) != 0) { 177 error("Certificate option \"%s\" corrupt " 178 "(extra data)", name); 179 goto out; 180 } 181 free(name); 182 name = NULL; 183 } 184 /* successfully parsed all options */ 185 ret = 0; 186 187 out: 188 free(name); 189 sshbuf_free(data); 190 sshbuf_free(c); 191 return ret; 192 } 193 194 struct sshauthopt * 195 sshauthopt_new(void) 196 { 197 struct sshauthopt *ret; 198 199 if ((ret = calloc(1, sizeof(*ret))) == NULL) 200 return NULL; 201 ret->force_tun_device = -1; 202 return ret; 203 } 204 205 void 206 sshauthopt_free(struct sshauthopt *opts) 207 { 208 size_t i; 209 210 if (opts == NULL) 211 return; 212 213 free(opts->cert_principals); 214 free(opts->force_command); 215 free(opts->required_from_host_cert); 216 free(opts->required_from_host_keys); 217 218 for (i = 0; i < opts->nenv; i++) 219 free(opts->env[i]); 220 free(opts->env); 221 222 for (i = 0; i < opts->npermitopen; i++) 223 free(opts->permitopen[i]); 224 free(opts->permitopen); 225 226 for (i = 0; i < opts->npermitlisten; i++) 227 free(opts->permitlisten[i]); 228 free(opts->permitlisten); 229 230 freezero(opts, sizeof(*opts)); 231 } 232 233 struct sshauthopt * 234 sshauthopt_new_with_keys_defaults(void) 235 { 236 struct sshauthopt *ret = NULL; 237 238 if ((ret = sshauthopt_new()) == NULL) 239 return NULL; 240 241 /* Defaults for authorized_keys flags */ 242 ret->permit_port_forwarding_flag = 1; 243 ret->permit_agent_forwarding_flag = 1; 244 ret->permit_x11_forwarding_flag = 1; 245 ret->permit_pty_flag = 1; 246 ret->permit_user_rc = 1; 247 return ret; 248 } 249 250 /* 251 * Parse and record a permitopen/permitlisten directive. 252 * Return 0 on success. Return -1 on failure and sets *errstrp to error reason. 253 */ 254 static int 255 handle_permit(const char **optsp, int allow_bare_port, 256 char ***permitsp, size_t *npermitsp, const char **errstrp) 257 { 258 char *opt, *tmp, *cp, *host, **permits = *permitsp; 259 size_t npermits = *npermitsp; 260 const char *errstr = "unknown error"; 261 262 if (npermits > SSH_AUTHOPT_PERMIT_MAX) { 263 *errstrp = "too many permission directives"; 264 return -1; 265 } 266 if ((opt = opt_dequote(optsp, &errstr)) == NULL) { 267 return -1; 268 } 269 if (allow_bare_port && strchr(opt, ':') == NULL) { 270 /* 271 * Allow a bare port number in permitlisten to indicate a 272 * listen_host wildcard. 273 */ 274 if (asprintf(&tmp, "*:%s", opt) == -1) { 275 free(opt); 276 *errstrp = "memory allocation failed"; 277 return -1; 278 } 279 free(opt); 280 opt = tmp; 281 } 282 if ((tmp = strdup(opt)) == NULL) { 283 free(opt); 284 *errstrp = "memory allocation failed"; 285 return -1; 286 } 287 cp = tmp; 288 /* validate syntax before recording it. */ 289 host = hpdelim2(&cp, NULL); 290 if (host == NULL || strlen(host) >= NI_MAXHOST) { 291 free(tmp); 292 free(opt); 293 *errstrp = "invalid permission hostname"; 294 return -1; 295 } 296 /* 297 * don't want to use permitopen_port to avoid 298 * dependency on channels.[ch] here. 299 */ 300 if (cp == NULL || 301 (strcmp(cp, "*") != 0 && a2port(cp) <= 0)) { 302 free(tmp); 303 free(opt); 304 *errstrp = "invalid permission port"; 305 return -1; 306 } 307 /* XXX - add streamlocal support */ 308 free(tmp); 309 /* Record it */ 310 if ((permits = recallocarray(permits, npermits, npermits + 1, 311 sizeof(*permits))) == NULL) { 312 free(opt); 313 /* NB. don't update *permitsp if alloc fails */ 314 *errstrp = "memory allocation failed"; 315 return -1; 316 } 317 permits[npermits++] = opt; 318 *permitsp = permits; 319 *npermitsp = npermits; 320 return 0; 321 } 322 323 struct sshauthopt * 324 sshauthopt_parse(const char *opts, const char **errstrp) 325 { 326 char **oarray, *opt, *cp, *tmp; 327 int r; 328 struct sshauthopt *ret = NULL; 329 const char *errstr = "unknown error"; 330 uint64_t valid_before; 331 size_t i, l; 332 333 if (errstrp != NULL) 334 *errstrp = NULL; 335 if ((ret = sshauthopt_new_with_keys_defaults()) == NULL) 336 goto alloc_fail; 337 338 if (opts == NULL) 339 return ret; 340 341 while (*opts && *opts != ' ' && *opts != '\t') { 342 /* flag options */ 343 if ((r = opt_flag("restrict", 0, &opts)) != -1) { 344 ret->restricted = 1; 345 ret->permit_port_forwarding_flag = 0; 346 ret->permit_agent_forwarding_flag = 0; 347 ret->permit_x11_forwarding_flag = 0; 348 ret->permit_pty_flag = 0; 349 ret->permit_user_rc = 0; 350 } else if ((r = opt_flag("cert-authority", 0, &opts)) != -1) { 351 ret->cert_authority = r; 352 } else if ((r = opt_flag("port-forwarding", 1, &opts)) != -1) { 353 ret->permit_port_forwarding_flag = r == 1; 354 } else if ((r = opt_flag("agent-forwarding", 1, &opts)) != -1) { 355 ret->permit_agent_forwarding_flag = r == 1; 356 } else if ((r = opt_flag("x11-forwarding", 1, &opts)) != -1) { 357 ret->permit_x11_forwarding_flag = r == 1; 358 } else if ((r = opt_flag("touch-required", 1, &opts)) != -1) { 359 ret->no_require_user_presence = r != 1; /* NB. flip */ 360 } else if ((r = opt_flag("verify-required", 1, &opts)) != -1) { 361 ret->require_verify = r == 1; 362 } else if ((r = opt_flag("pty", 1, &opts)) != -1) { 363 ret->permit_pty_flag = r == 1; 364 } else if ((r = opt_flag("user-rc", 1, &opts)) != -1) { 365 ret->permit_user_rc = r == 1; 366 } else if (opt_match(&opts, "command")) { 367 if (ret->force_command != NULL) { 368 errstr = "multiple \"command\" clauses"; 369 goto fail; 370 } 371 ret->force_command = opt_dequote(&opts, &errstr); 372 if (ret->force_command == NULL) 373 goto fail; 374 } else if (opt_match(&opts, "principals")) { 375 if (ret->cert_principals != NULL) { 376 errstr = "multiple \"principals\" clauses"; 377 goto fail; 378 } 379 ret->cert_principals = opt_dequote(&opts, &errstr); 380 if (ret->cert_principals == NULL) 381 goto fail; 382 } else if (opt_match(&opts, "from")) { 383 if (ret->required_from_host_keys != NULL) { 384 errstr = "multiple \"from\" clauses"; 385 goto fail; 386 } 387 ret->required_from_host_keys = opt_dequote(&opts, 388 &errstr); 389 if (ret->required_from_host_keys == NULL) 390 goto fail; 391 } else if (opt_match(&opts, "expiry-time")) { 392 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 393 goto fail; 394 if (parse_absolute_time(opt, &valid_before) != 0 || 395 valid_before == 0) { 396 free(opt); 397 errstr = "invalid expires time"; 398 goto fail; 399 } 400 free(opt); 401 if (ret->valid_before == 0 || 402 valid_before < ret->valid_before) 403 ret->valid_before = valid_before; 404 } else if (opt_match(&opts, "environment")) { 405 if (ret->nenv > SSH_AUTHOPT_ENV_MAX) { 406 errstr = "too many environment strings"; 407 goto fail; 408 } 409 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 410 goto fail; 411 /* env name must be alphanumeric and followed by '=' */ 412 if ((tmp = strchr(opt, '=')) == NULL) { 413 free(opt); 414 errstr = "invalid environment string"; 415 goto fail; 416 } 417 if ((cp = strdup(opt)) == NULL) { 418 free(opt); 419 goto alloc_fail; 420 } 421 l = (size_t)(tmp - opt); 422 cp[l] = '\0'; /* truncate at '=' */ 423 if (!valid_env_name(cp)) { 424 free(cp); 425 free(opt); 426 errstr = "invalid environment string"; 427 goto fail; 428 } 429 /* Check for duplicates; XXX O(n*log(n)) */ 430 for (i = 0; i < ret->nenv; i++) { 431 if (strncmp(ret->env[i], cp, l) == 0 && 432 ret->env[i][l] == '=') 433 break; 434 } 435 free(cp); 436 /* First match wins */ 437 if (i >= ret->nenv) { 438 /* Append it. */ 439 oarray = ret->env; 440 if ((ret->env = recallocarray(ret->env, 441 ret->nenv, ret->nenv + 1, 442 sizeof(*ret->env))) == NULL) { 443 free(opt); 444 /* put it back for cleanup */ 445 ret->env = oarray; 446 goto alloc_fail; 447 } 448 ret->env[ret->nenv++] = opt; 449 opt = NULL; /* transferred */ 450 } 451 free(opt); 452 } else if (opt_match(&opts, "permitopen")) { 453 if (handle_permit(&opts, 0, &ret->permitopen, 454 &ret->npermitopen, &errstr) != 0) 455 goto fail; 456 } else if (opt_match(&opts, "permitlisten")) { 457 if (handle_permit(&opts, 1, &ret->permitlisten, 458 &ret->npermitlisten, &errstr) != 0) 459 goto fail; 460 } else if (opt_match(&opts, "tunnel")) { 461 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 462 goto fail; 463 ret->force_tun_device = a2tun(opt, NULL); 464 free(opt); 465 if (ret->force_tun_device == SSH_TUNID_ERR) { 466 errstr = "invalid tun device"; 467 goto fail; 468 } 469 } 470 /* 471 * Skip the comma, and move to the next option 472 * (or break out if there are no more). 473 */ 474 if (*opts == '\0' || *opts == ' ' || *opts == '\t') 475 break; /* End of options. */ 476 /* Anything other than a comma is an unknown option */ 477 if (*opts != ',') { 478 errstr = "unknown key option"; 479 goto fail; 480 } 481 opts++; 482 if (*opts == '\0') { 483 errstr = "unexpected end-of-options"; 484 goto fail; 485 } 486 } 487 488 /* success */ 489 if (errstrp != NULL) 490 *errstrp = NULL; 491 return ret; 492 493 alloc_fail: 494 errstr = "memory allocation failed"; 495 fail: 496 sshauthopt_free(ret); 497 if (errstrp != NULL) 498 *errstrp = errstr; 499 return NULL; 500 } 501 502 struct sshauthopt * 503 sshauthopt_from_cert(struct sshkey *k) 504 { 505 struct sshauthopt *ret; 506 507 if (k == NULL || !sshkey_type_is_cert(k->type) || k->cert == NULL || 508 k->cert->type != SSH2_CERT_TYPE_USER) 509 return NULL; 510 511 if ((ret = sshauthopt_new()) == NULL) 512 return NULL; 513 514 /* Handle options and critical extensions separately */ 515 if (cert_option_list(ret, k->cert->critical, 516 OPTIONS_CRITICAL, 1) == -1) { 517 sshauthopt_free(ret); 518 return NULL; 519 } 520 if (cert_option_list(ret, k->cert->extensions, 521 OPTIONS_EXTENSIONS, 0) == -1) { 522 sshauthopt_free(ret); 523 return NULL; 524 } 525 /* success */ 526 return ret; 527 } 528 529 /* 530 * Merges "additional" options to "primary" and returns the result. 531 * NB. Some options from primary have primacy. 532 */ 533 struct sshauthopt * 534 sshauthopt_merge(const struct sshauthopt *primary, 535 const struct sshauthopt *additional, const char **errstrp) 536 { 537 struct sshauthopt *ret; 538 const char *errstr = "internal error"; 539 const char *tmp; 540 541 if (errstrp != NULL) 542 *errstrp = NULL; 543 544 if ((ret = sshauthopt_new()) == NULL) 545 goto alloc_fail; 546 547 /* cert_authority and cert_principals are cleared in result */ 548 549 /* Prefer access lists from primary. */ 550 /* XXX err is both set and mismatch? */ 551 tmp = primary->required_from_host_cert; 552 if (tmp == NULL) 553 tmp = additional->required_from_host_cert; 554 if (tmp != NULL && (ret->required_from_host_cert = strdup(tmp)) == NULL) 555 goto alloc_fail; 556 tmp = primary->required_from_host_keys; 557 if (tmp == NULL) 558 tmp = additional->required_from_host_keys; 559 if (tmp != NULL && (ret->required_from_host_keys = strdup(tmp)) == NULL) 560 goto alloc_fail; 561 562 /* 563 * force_tun_device, permitopen/permitlisten and environment all 564 * prefer the primary. 565 */ 566 ret->force_tun_device = primary->force_tun_device; 567 if (ret->force_tun_device == -1) 568 ret->force_tun_device = additional->force_tun_device; 569 if (primary->nenv > 0) { 570 if (dup_strings(&ret->env, &ret->nenv, 571 primary->env, primary->nenv) != 0) 572 goto alloc_fail; 573 } else if (additional->nenv) { 574 if (dup_strings(&ret->env, &ret->nenv, 575 additional->env, additional->nenv) != 0) 576 goto alloc_fail; 577 } 578 if (primary->npermitopen > 0) { 579 if (dup_strings(&ret->permitopen, &ret->npermitopen, 580 primary->permitopen, primary->npermitopen) != 0) 581 goto alloc_fail; 582 } else if (additional->npermitopen > 0) { 583 if (dup_strings(&ret->permitopen, &ret->npermitopen, 584 additional->permitopen, additional->npermitopen) != 0) 585 goto alloc_fail; 586 } 587 588 if (primary->npermitlisten > 0) { 589 if (dup_strings(&ret->permitlisten, &ret->npermitlisten, 590 primary->permitlisten, primary->npermitlisten) != 0) 591 goto alloc_fail; 592 } else if (additional->npermitlisten > 0) { 593 if (dup_strings(&ret->permitlisten, &ret->npermitlisten, 594 additional->permitlisten, additional->npermitlisten) != 0) 595 goto alloc_fail; 596 } 597 598 #define OPTFLAG_AND(x) ret->x = (primary->x == 1) && (additional->x == 1) 599 #define OPTFLAG_OR(x) ret->x = (primary->x == 1) || (additional->x == 1) 600 /* Permissive flags are logical-AND (i.e. must be set in both) */ 601 OPTFLAG_AND(permit_port_forwarding_flag); 602 OPTFLAG_AND(permit_agent_forwarding_flag); 603 OPTFLAG_AND(permit_x11_forwarding_flag); 604 OPTFLAG_AND(permit_pty_flag); 605 OPTFLAG_AND(permit_user_rc); 606 OPTFLAG_AND(no_require_user_presence); 607 /* Restrictive flags are logical-OR (i.e. must be set in either) */ 608 OPTFLAG_OR(require_verify); 609 #undef OPTFLAG_AND 610 611 /* Earliest expiry time should win */ 612 if (primary->valid_before != 0) 613 ret->valid_before = primary->valid_before; 614 if (additional->valid_before != 0 && 615 additional->valid_before < ret->valid_before) 616 ret->valid_before = additional->valid_before; 617 618 /* 619 * When both multiple forced-command are specified, only 620 * proceed if they are identical, otherwise fail. 621 */ 622 if (primary->force_command != NULL && 623 additional->force_command != NULL) { 624 if (strcmp(primary->force_command, 625 additional->force_command) == 0) { 626 /* ok */ 627 ret->force_command = strdup(primary->force_command); 628 if (ret->force_command == NULL) 629 goto alloc_fail; 630 } else { 631 errstr = "forced command options do not match"; 632 goto fail; 633 } 634 } else if (primary->force_command != NULL) { 635 if ((ret->force_command = strdup( 636 primary->force_command)) == NULL) 637 goto alloc_fail; 638 } else if (additional->force_command != NULL) { 639 if ((ret->force_command = strdup( 640 additional->force_command)) == NULL) 641 goto alloc_fail; 642 } 643 /* success */ 644 if (errstrp != NULL) 645 *errstrp = NULL; 646 return ret; 647 648 alloc_fail: 649 errstr = "memory allocation failed"; 650 fail: 651 if (errstrp != NULL) 652 *errstrp = errstr; 653 sshauthopt_free(ret); 654 return NULL; 655 } 656 657 /* 658 * Copy options 659 */ 660 struct sshauthopt * 661 sshauthopt_copy(const struct sshauthopt *orig) 662 { 663 struct sshauthopt *ret; 664 665 if ((ret = sshauthopt_new()) == NULL) 666 return NULL; 667 668 #define OPTSCALAR(x) ret->x = orig->x 669 OPTSCALAR(permit_port_forwarding_flag); 670 OPTSCALAR(permit_agent_forwarding_flag); 671 OPTSCALAR(permit_x11_forwarding_flag); 672 OPTSCALAR(permit_pty_flag); 673 OPTSCALAR(permit_user_rc); 674 OPTSCALAR(restricted); 675 OPTSCALAR(cert_authority); 676 OPTSCALAR(force_tun_device); 677 OPTSCALAR(valid_before); 678 OPTSCALAR(no_require_user_presence); 679 OPTSCALAR(require_verify); 680 #undef OPTSCALAR 681 #define OPTSTRING(x) \ 682 do { \ 683 if (orig->x != NULL && (ret->x = strdup(orig->x)) == NULL) { \ 684 sshauthopt_free(ret); \ 685 return NULL; \ 686 } \ 687 } while (0) 688 OPTSTRING(cert_principals); 689 OPTSTRING(force_command); 690 OPTSTRING(required_from_host_cert); 691 OPTSTRING(required_from_host_keys); 692 #undef OPTSTRING 693 694 if (dup_strings(&ret->env, &ret->nenv, orig->env, orig->nenv) != 0 || 695 dup_strings(&ret->permitopen, &ret->npermitopen, 696 orig->permitopen, orig->npermitopen) != 0 || 697 dup_strings(&ret->permitlisten, &ret->npermitlisten, 698 orig->permitlisten, orig->npermitlisten) != 0) { 699 sshauthopt_free(ret); 700 return NULL; 701 } 702 return ret; 703 } 704 705 static int 706 serialise_array(struct sshbuf *m, char **a, size_t n) 707 { 708 struct sshbuf *b; 709 size_t i; 710 int r = SSH_ERR_INTERNAL_ERROR; 711 712 if (n > INT_MAX) 713 return SSH_ERR_INTERNAL_ERROR; 714 715 if ((b = sshbuf_new()) == NULL) { 716 return SSH_ERR_ALLOC_FAIL; 717 } 718 for (i = 0; i < n; i++) { 719 if ((r = sshbuf_put_cstring(b, a[i])) != 0) 720 goto out; 721 } 722 if ((r = sshbuf_put_u32(m, n)) != 0 || 723 (r = sshbuf_put_stringb(m, b)) != 0) 724 goto out; 725 /* success */ 726 r = 0; 727 out: 728 sshbuf_free(b); 729 return r; 730 } 731 732 static int 733 deserialise_array(struct sshbuf *m, char ***ap, size_t *np) 734 { 735 char **a = NULL; 736 size_t i, n = 0; 737 struct sshbuf *b = NULL; 738 u_int tmp; 739 int r = SSH_ERR_INTERNAL_ERROR; 740 741 if ((r = sshbuf_get_u32(m, &tmp)) != 0 || 742 (r = sshbuf_froms(m, &b)) != 0) 743 goto out; 744 if (tmp > INT_MAX) { 745 r = SSH_ERR_INVALID_FORMAT; 746 goto out; 747 } 748 n = tmp; 749 if (n > 0 && (a = calloc(n, sizeof(*a))) == NULL) { 750 r = SSH_ERR_ALLOC_FAIL; 751 goto out; 752 } 753 for (i = 0; i < n; i++) { 754 if ((r = sshbuf_get_cstring(b, &a[i], NULL)) != 0) 755 goto out; 756 } 757 /* success */ 758 r = 0; 759 *ap = a; 760 a = NULL; 761 *np = n; 762 n = 0; 763 out: 764 if (a != NULL) { 765 for (i = 0; i < n; i++) 766 free(a[i]); 767 free(a); 768 } 769 sshbuf_free(b); 770 return r; 771 } 772 773 static int 774 serialise_nullable_string(struct sshbuf *m, const char *s) 775 { 776 int r; 777 778 if ((r = sshbuf_put_u8(m, s == NULL)) != 0 || 779 (r = sshbuf_put_cstring(m, s)) != 0) 780 return r; 781 return 0; 782 } 783 784 static int 785 deserialise_nullable_string(struct sshbuf *m, char **sp) 786 { 787 int r; 788 u_char flag; 789 790 *sp = NULL; 791 if ((r = sshbuf_get_u8(m, &flag)) != 0 || 792 (r = sshbuf_get_cstring(m, flag ? NULL : sp, NULL)) != 0) 793 return r; 794 return 0; 795 } 796 797 int 798 sshauthopt_serialise(const struct sshauthopt *opts, struct sshbuf *m, 799 int untrusted) 800 { 801 int r = SSH_ERR_INTERNAL_ERROR; 802 803 /* Flag options */ 804 if ((r = sshbuf_put_u8(m, opts->permit_port_forwarding_flag)) != 0 || 805 (r = sshbuf_put_u8(m, opts->permit_agent_forwarding_flag)) != 0 || 806 (r = sshbuf_put_u8(m, opts->permit_x11_forwarding_flag)) != 0 || 807 (r = sshbuf_put_u8(m, opts->permit_pty_flag)) != 0 || 808 (r = sshbuf_put_u8(m, opts->permit_user_rc)) != 0 || 809 (r = sshbuf_put_u8(m, opts->restricted)) != 0 || 810 (r = sshbuf_put_u8(m, opts->cert_authority)) != 0 || 811 (r = sshbuf_put_u8(m, opts->no_require_user_presence)) != 0 || 812 (r = sshbuf_put_u8(m, opts->require_verify)) != 0) 813 return r; 814 815 /* Simple integer options */ 816 if ((r = sshbuf_put_u64(m, opts->valid_before)) != 0) 817 return r; 818 819 /* tunnel number can be negative to indicate "unset" */ 820 if ((r = sshbuf_put_u8(m, opts->force_tun_device == -1)) != 0 || 821 (r = sshbuf_put_u32(m, (opts->force_tun_device < 0) ? 822 0 : (u_int)opts->force_tun_device)) != 0) 823 return r; 824 825 /* String options; these may be NULL */ 826 if ((r = serialise_nullable_string(m, 827 untrusted ? "yes" : opts->cert_principals)) != 0 || 828 (r = serialise_nullable_string(m, 829 untrusted ? "true" : opts->force_command)) != 0 || 830 (r = serialise_nullable_string(m, 831 untrusted ? NULL : opts->required_from_host_cert)) != 0 || 832 (r = serialise_nullable_string(m, 833 untrusted ? NULL : opts->required_from_host_keys)) != 0) 834 return r; 835 836 /* Array options */ 837 if ((r = serialise_array(m, opts->env, 838 untrusted ? 0 : opts->nenv)) != 0 || 839 (r = serialise_array(m, opts->permitopen, 840 untrusted ? 0 : opts->npermitopen)) != 0 || 841 (r = serialise_array(m, opts->permitlisten, 842 untrusted ? 0 : opts->npermitlisten)) != 0) 843 return r; 844 845 /* success */ 846 return 0; 847 } 848 849 int 850 sshauthopt_deserialise(struct sshbuf *m, struct sshauthopt **optsp) 851 { 852 struct sshauthopt *opts = NULL; 853 int r = SSH_ERR_INTERNAL_ERROR; 854 u_char f; 855 u_int tmp; 856 857 if ((opts = calloc(1, sizeof(*opts))) == NULL) 858 return SSH_ERR_ALLOC_FAIL; 859 860 /* Flag options */ 861 #define OPT_FLAG(x) \ 862 do { \ 863 if ((r = sshbuf_get_u8(m, &f)) != 0) \ 864 goto out; \ 865 opts->x = f; \ 866 } while (0) 867 OPT_FLAG(permit_port_forwarding_flag); 868 OPT_FLAG(permit_agent_forwarding_flag); 869 OPT_FLAG(permit_x11_forwarding_flag); 870 OPT_FLAG(permit_pty_flag); 871 OPT_FLAG(permit_user_rc); 872 OPT_FLAG(restricted); 873 OPT_FLAG(cert_authority); 874 OPT_FLAG(no_require_user_presence); 875 OPT_FLAG(require_verify); 876 #undef OPT_FLAG 877 878 /* Simple integer options */ 879 if ((r = sshbuf_get_u64(m, &opts->valid_before)) != 0) 880 goto out; 881 882 /* tunnel number can be negative to indicate "unset" */ 883 if ((r = sshbuf_get_u8(m, &f)) != 0 || 884 (r = sshbuf_get_u32(m, &tmp)) != 0) 885 goto out; 886 opts->force_tun_device = f ? -1 : (int)tmp; 887 888 /* String options may be NULL */ 889 if ((r = deserialise_nullable_string(m, &opts->cert_principals)) != 0 || 890 (r = deserialise_nullable_string(m, &opts->force_command)) != 0 || 891 (r = deserialise_nullable_string(m, 892 &opts->required_from_host_cert)) != 0 || 893 (r = deserialise_nullable_string(m, 894 &opts->required_from_host_keys)) != 0) 895 goto out; 896 897 /* Array options */ 898 if ((r = deserialise_array(m, &opts->env, &opts->nenv)) != 0 || 899 (r = deserialise_array(m, 900 &opts->permitopen, &opts->npermitopen)) != 0 || 901 (r = deserialise_array(m, 902 &opts->permitlisten, &opts->npermitlisten)) != 0) 903 goto out; 904 905 /* success */ 906 r = 0; 907 *optsp = opts; 908 opts = NULL; 909 out: 910 sshauthopt_free(opts); 911 return r; 912 } 913