1 /* $OpenBSD: auth-options.c,v 1.99 2023/03/29 00:18:35 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 <stdlib.h> 22 #include <netdb.h> 23 #include <pwd.h> 24 #include <string.h> 25 #include <stdio.h> 26 #include <stdarg.h> 27 #include <ctype.h> 28 #include <limits.h> 29 30 #include "xmalloc.h" 31 #include "ssherr.h" 32 #include "log.h" 33 #include "sshbuf.h" 34 #include "misc.h" 35 #include "sshkey.h" 36 #include "match.h" 37 #include "ssh2.h" 38 #include "auth-options.h" 39 40 static int 41 dup_strings(char ***dstp, size_t *ndstp, char **src, size_t nsrc) 42 { 43 char **dst; 44 size_t i, j; 45 46 *dstp = NULL; 47 *ndstp = 0; 48 if (nsrc == 0) 49 return 0; 50 51 if ((dst = calloc(nsrc, sizeof(*src))) == NULL) 52 return -1; 53 for (i = 0; i < nsrc; i++) { 54 if ((dst[i] = strdup(src[i])) == NULL) { 55 for (j = 0; j < i; j++) 56 free(dst[j]); 57 free(dst); 58 return -1; 59 } 60 } 61 /* success */ 62 *dstp = dst; 63 *ndstp = nsrc; 64 return 0; 65 } 66 67 #define OPTIONS_CRITICAL 1 68 #define OPTIONS_EXTENSIONS 2 69 static int 70 cert_option_list(struct sshauthopt *opts, struct sshbuf *oblob, 71 u_int which, int crit) 72 { 73 char *command, *allowed; 74 char *name = NULL; 75 struct sshbuf *c = NULL, *data = NULL; 76 int r, ret = -1, found; 77 78 if ((c = sshbuf_fromb(oblob)) == NULL) { 79 error_f("sshbuf_fromb failed"); 80 goto out; 81 } 82 83 while (sshbuf_len(c) > 0) { 84 sshbuf_free(data); 85 data = NULL; 86 if ((r = sshbuf_get_cstring(c, &name, NULL)) != 0 || 87 (r = sshbuf_froms(c, &data)) != 0) { 88 error_r(r, "Unable to parse certificate options"); 89 goto out; 90 } 91 debug3("found certificate option \"%.100s\" len %zu", 92 name, sshbuf_len(data)); 93 found = 0; 94 if ((which & OPTIONS_EXTENSIONS) != 0) { 95 if (strcmp(name, "no-touch-required") == 0) { 96 opts->no_require_user_presence = 1; 97 found = 1; 98 } else if (strcmp(name, "permit-X11-forwarding") == 0) { 99 opts->permit_x11_forwarding_flag = 1; 100 found = 1; 101 } else if (strcmp(name, 102 "permit-agent-forwarding") == 0) { 103 opts->permit_agent_forwarding_flag = 1; 104 found = 1; 105 } else if (strcmp(name, 106 "permit-port-forwarding") == 0) { 107 opts->permit_port_forwarding_flag = 1; 108 found = 1; 109 } else if (strcmp(name, "permit-pty") == 0) { 110 opts->permit_pty_flag = 1; 111 found = 1; 112 } else if (strcmp(name, "permit-user-rc") == 0) { 113 opts->permit_user_rc = 1; 114 found = 1; 115 } 116 } 117 if (!found && (which & OPTIONS_CRITICAL) != 0) { 118 if (strcmp(name, "verify-required") == 0) { 119 opts->require_verify = 1; 120 found = 1; 121 } else if (strcmp(name, "force-command") == 0) { 122 if ((r = sshbuf_get_cstring(data, &command, 123 NULL)) != 0) { 124 error_r(r, "Unable to parse \"%s\" " 125 "section", name); 126 goto out; 127 } 128 if (opts->force_command != NULL) { 129 error("Certificate has multiple " 130 "force-command options"); 131 free(command); 132 goto out; 133 } 134 opts->force_command = command; 135 found = 1; 136 } else if (strcmp(name, "source-address") == 0) { 137 if ((r = sshbuf_get_cstring(data, &allowed, 138 NULL)) != 0) { 139 error_r(r, "Unable to parse \"%s\" " 140 "section", name); 141 goto out; 142 } 143 if (opts->required_from_host_cert != NULL) { 144 error("Certificate has multiple " 145 "source-address options"); 146 free(allowed); 147 goto out; 148 } 149 /* Check syntax */ 150 if (addr_match_cidr_list(NULL, allowed) == -1) { 151 error("Certificate source-address " 152 "contents invalid"); 153 goto out; 154 } 155 opts->required_from_host_cert = allowed; 156 found = 1; 157 } 158 } 159 160 if (!found) { 161 if (crit) { 162 error("Certificate critical option \"%s\" " 163 "is not supported", name); 164 goto out; 165 } else { 166 logit("Certificate extension \"%s\" " 167 "is not supported", name); 168 } 169 } else if (sshbuf_len(data) != 0) { 170 error("Certificate option \"%s\" corrupt " 171 "(extra data)", name); 172 goto out; 173 } 174 free(name); 175 name = NULL; 176 } 177 /* successfully parsed all options */ 178 ret = 0; 179 180 out: 181 free(name); 182 sshbuf_free(data); 183 sshbuf_free(c); 184 return ret; 185 } 186 187 struct sshauthopt * 188 sshauthopt_new(void) 189 { 190 struct sshauthopt *ret; 191 192 if ((ret = calloc(1, sizeof(*ret))) == NULL) 193 return NULL; 194 ret->force_tun_device = -1; 195 return ret; 196 } 197 198 void 199 sshauthopt_free(struct sshauthopt *opts) 200 { 201 size_t i; 202 203 if (opts == NULL) 204 return; 205 206 free(opts->cert_principals); 207 free(opts->force_command); 208 free(opts->required_from_host_cert); 209 free(opts->required_from_host_keys); 210 211 for (i = 0; i < opts->nenv; i++) 212 free(opts->env[i]); 213 free(opts->env); 214 215 for (i = 0; i < opts->npermitopen; i++) 216 free(opts->permitopen[i]); 217 free(opts->permitopen); 218 219 for (i = 0; i < opts->npermitlisten; i++) 220 free(opts->permitlisten[i]); 221 free(opts->permitlisten); 222 223 freezero(opts, sizeof(*opts)); 224 } 225 226 struct sshauthopt * 227 sshauthopt_new_with_keys_defaults(void) 228 { 229 struct sshauthopt *ret = NULL; 230 231 if ((ret = sshauthopt_new()) == NULL) 232 return NULL; 233 234 /* Defaults for authorized_keys flags */ 235 ret->permit_port_forwarding_flag = 1; 236 ret->permit_agent_forwarding_flag = 1; 237 ret->permit_x11_forwarding_flag = 1; 238 ret->permit_pty_flag = 1; 239 ret->permit_user_rc = 1; 240 return ret; 241 } 242 243 /* 244 * Parse and record a permitopen/permitlisten directive. 245 * Return 0 on success. Return -1 on failure and sets *errstrp to error reason. 246 */ 247 static int 248 handle_permit(const char **optsp, int allow_bare_port, 249 char ***permitsp, size_t *npermitsp, const char **errstrp) 250 { 251 char *opt, *tmp, *cp, *host, **permits = *permitsp; 252 size_t npermits = *npermitsp; 253 const char *errstr = "unknown error"; 254 255 if (npermits > SSH_AUTHOPT_PERMIT_MAX) { 256 *errstrp = "too many permission directives"; 257 return -1; 258 } 259 if ((opt = opt_dequote(optsp, &errstr)) == NULL) { 260 return -1; 261 } 262 if (allow_bare_port && strchr(opt, ':') == NULL) { 263 /* 264 * Allow a bare port number in permitlisten to indicate a 265 * listen_host wildcard. 266 */ 267 if (asprintf(&tmp, "*:%s", opt) == -1) { 268 free(opt); 269 *errstrp = "memory allocation failed"; 270 return -1; 271 } 272 free(opt); 273 opt = tmp; 274 } 275 if ((tmp = strdup(opt)) == NULL) { 276 free(opt); 277 *errstrp = "memory allocation failed"; 278 return -1; 279 } 280 cp = tmp; 281 /* validate syntax before recording it. */ 282 host = hpdelim2(&cp, NULL); 283 if (host == NULL || strlen(host) >= NI_MAXHOST) { 284 free(tmp); 285 free(opt); 286 *errstrp = "invalid permission hostname"; 287 return -1; 288 } 289 /* 290 * don't want to use permitopen_port to avoid 291 * dependency on channels.[ch] here. 292 */ 293 if (cp == NULL || 294 (strcmp(cp, "*") != 0 && a2port(cp) <= 0)) { 295 free(tmp); 296 free(opt); 297 *errstrp = "invalid permission port"; 298 return -1; 299 } 300 /* XXX - add streamlocal support */ 301 free(tmp); 302 /* Record it */ 303 if ((permits = recallocarray(permits, npermits, npermits + 1, 304 sizeof(*permits))) == NULL) { 305 free(opt); 306 /* NB. don't update *permitsp if alloc fails */ 307 *errstrp = "memory allocation failed"; 308 return -1; 309 } 310 permits[npermits++] = opt; 311 *permitsp = permits; 312 *npermitsp = npermits; 313 return 0; 314 } 315 316 struct sshauthopt * 317 sshauthopt_parse(const char *opts, const char **errstrp) 318 { 319 char **oarray, *opt, *cp, *tmp; 320 int r; 321 struct sshauthopt *ret = NULL; 322 const char *errstr = "unknown error"; 323 uint64_t valid_before; 324 size_t i, l; 325 326 if (errstrp != NULL) 327 *errstrp = NULL; 328 if ((ret = sshauthopt_new_with_keys_defaults()) == NULL) 329 goto alloc_fail; 330 331 if (opts == NULL) 332 return ret; 333 334 while (*opts && *opts != ' ' && *opts != '\t') { 335 /* flag options */ 336 if ((r = opt_flag("restrict", 0, &opts)) != -1) { 337 ret->restricted = 1; 338 ret->permit_port_forwarding_flag = 0; 339 ret->permit_agent_forwarding_flag = 0; 340 ret->permit_x11_forwarding_flag = 0; 341 ret->permit_pty_flag = 0; 342 ret->permit_user_rc = 0; 343 } else if ((r = opt_flag("cert-authority", 0, &opts)) != -1) { 344 ret->cert_authority = r; 345 } else if ((r = opt_flag("port-forwarding", 1, &opts)) != -1) { 346 ret->permit_port_forwarding_flag = r == 1; 347 } else if ((r = opt_flag("agent-forwarding", 1, &opts)) != -1) { 348 ret->permit_agent_forwarding_flag = r == 1; 349 } else if ((r = opt_flag("x11-forwarding", 1, &opts)) != -1) { 350 ret->permit_x11_forwarding_flag = r == 1; 351 } else if ((r = opt_flag("touch-required", 1, &opts)) != -1) { 352 ret->no_require_user_presence = r != 1; /* NB. flip */ 353 } else if ((r = opt_flag("verify-required", 1, &opts)) != -1) { 354 ret->require_verify = r == 1; 355 } else if ((r = opt_flag("pty", 1, &opts)) != -1) { 356 ret->permit_pty_flag = r == 1; 357 } else if ((r = opt_flag("user-rc", 1, &opts)) != -1) { 358 ret->permit_user_rc = r == 1; 359 } else if (opt_match(&opts, "command")) { 360 if (ret->force_command != NULL) { 361 errstr = "multiple \"command\" clauses"; 362 goto fail; 363 } 364 ret->force_command = opt_dequote(&opts, &errstr); 365 if (ret->force_command == NULL) 366 goto fail; 367 } else if (opt_match(&opts, "principals")) { 368 if (ret->cert_principals != NULL) { 369 errstr = "multiple \"principals\" clauses"; 370 goto fail; 371 } 372 ret->cert_principals = opt_dequote(&opts, &errstr); 373 if (ret->cert_principals == NULL) 374 goto fail; 375 } else if (opt_match(&opts, "from")) { 376 if (ret->required_from_host_keys != NULL) { 377 errstr = "multiple \"from\" clauses"; 378 goto fail; 379 } 380 ret->required_from_host_keys = opt_dequote(&opts, 381 &errstr); 382 if (ret->required_from_host_keys == NULL) 383 goto fail; 384 } else if (opt_match(&opts, "expiry-time")) { 385 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 386 goto fail; 387 if (parse_absolute_time(opt, &valid_before) != 0 || 388 valid_before == 0) { 389 free(opt); 390 errstr = "invalid expires time"; 391 goto fail; 392 } 393 free(opt); 394 if (ret->valid_before == 0 || 395 valid_before < ret->valid_before) 396 ret->valid_before = valid_before; 397 } else if (opt_match(&opts, "environment")) { 398 if (ret->nenv > SSH_AUTHOPT_ENV_MAX) { 399 errstr = "too many environment strings"; 400 goto fail; 401 } 402 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 403 goto fail; 404 /* env name must be alphanumeric and followed by '=' */ 405 if ((tmp = strchr(opt, '=')) == NULL) { 406 free(opt); 407 errstr = "invalid environment string"; 408 goto fail; 409 } 410 if ((cp = strdup(opt)) == NULL) { 411 free(opt); 412 goto alloc_fail; 413 } 414 l = (size_t)(tmp - opt); 415 cp[l] = '\0'; /* truncate at '=' */ 416 if (!valid_env_name(cp)) { 417 free(cp); 418 free(opt); 419 errstr = "invalid environment string"; 420 goto fail; 421 } 422 /* Check for duplicates; XXX O(n*log(n)) */ 423 for (i = 0; i < ret->nenv; i++) { 424 if (strncmp(ret->env[i], cp, l) == 0 && 425 ret->env[i][l] == '=') 426 break; 427 } 428 free(cp); 429 /* First match wins */ 430 if (i >= ret->nenv) { 431 /* Append it. */ 432 oarray = ret->env; 433 if ((ret->env = recallocarray(ret->env, 434 ret->nenv, ret->nenv + 1, 435 sizeof(*ret->env))) == NULL) { 436 free(opt); 437 /* put it back for cleanup */ 438 ret->env = oarray; 439 goto alloc_fail; 440 } 441 ret->env[ret->nenv++] = opt; 442 opt = NULL; /* transferred */ 443 } 444 free(opt); 445 } else if (opt_match(&opts, "permitopen")) { 446 if (handle_permit(&opts, 0, &ret->permitopen, 447 &ret->npermitopen, &errstr) != 0) 448 goto fail; 449 } else if (opt_match(&opts, "permitlisten")) { 450 if (handle_permit(&opts, 1, &ret->permitlisten, 451 &ret->npermitlisten, &errstr) != 0) 452 goto fail; 453 } else if (opt_match(&opts, "tunnel")) { 454 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 455 goto fail; 456 ret->force_tun_device = a2tun(opt, NULL); 457 free(opt); 458 if (ret->force_tun_device == SSH_TUNID_ERR) { 459 errstr = "invalid tun device"; 460 goto fail; 461 } 462 } 463 /* 464 * Skip the comma, and move to the next option 465 * (or break out if there are no more). 466 */ 467 if (*opts == '\0' || *opts == ' ' || *opts == '\t') 468 break; /* End of options. */ 469 /* Anything other than a comma is an unknown option */ 470 if (*opts != ',') { 471 errstr = "unknown key option"; 472 goto fail; 473 } 474 opts++; 475 if (*opts == '\0') { 476 errstr = "unexpected end-of-options"; 477 goto fail; 478 } 479 } 480 481 /* success */ 482 if (errstrp != NULL) 483 *errstrp = NULL; 484 return ret; 485 486 alloc_fail: 487 errstr = "memory allocation failed"; 488 fail: 489 sshauthopt_free(ret); 490 if (errstrp != NULL) 491 *errstrp = errstr; 492 return NULL; 493 } 494 495 struct sshauthopt * 496 sshauthopt_from_cert(struct sshkey *k) 497 { 498 struct sshauthopt *ret; 499 500 if (k == NULL || !sshkey_type_is_cert(k->type) || k->cert == NULL || 501 k->cert->type != SSH2_CERT_TYPE_USER) 502 return NULL; 503 504 if ((ret = sshauthopt_new()) == NULL) 505 return NULL; 506 507 /* Handle options and critical extensions separately */ 508 if (cert_option_list(ret, k->cert->critical, 509 OPTIONS_CRITICAL, 1) == -1) { 510 sshauthopt_free(ret); 511 return NULL; 512 } 513 if (cert_option_list(ret, k->cert->extensions, 514 OPTIONS_EXTENSIONS, 0) == -1) { 515 sshauthopt_free(ret); 516 return NULL; 517 } 518 /* success */ 519 return ret; 520 } 521 522 /* 523 * Merges "additional" options to "primary" and returns the result. 524 * NB. Some options from primary have primacy. 525 */ 526 struct sshauthopt * 527 sshauthopt_merge(const struct sshauthopt *primary, 528 const struct sshauthopt *additional, const char **errstrp) 529 { 530 struct sshauthopt *ret; 531 const char *errstr = "internal error"; 532 const char *tmp; 533 534 if (errstrp != NULL) 535 *errstrp = NULL; 536 537 if ((ret = sshauthopt_new()) == NULL) 538 goto alloc_fail; 539 540 /* cert_authority and cert_principals are cleared in result */ 541 542 /* Prefer access lists from primary. */ 543 /* XXX err is both set and mismatch? */ 544 tmp = primary->required_from_host_cert; 545 if (tmp == NULL) 546 tmp = additional->required_from_host_cert; 547 if (tmp != NULL && (ret->required_from_host_cert = strdup(tmp)) == NULL) 548 goto alloc_fail; 549 tmp = primary->required_from_host_keys; 550 if (tmp == NULL) 551 tmp = additional->required_from_host_keys; 552 if (tmp != NULL && (ret->required_from_host_keys = strdup(tmp)) == NULL) 553 goto alloc_fail; 554 555 /* 556 * force_tun_device, permitopen/permitlisten and environment all 557 * prefer the primary. 558 */ 559 ret->force_tun_device = primary->force_tun_device; 560 if (ret->force_tun_device == -1) 561 ret->force_tun_device = additional->force_tun_device; 562 if (primary->nenv > 0) { 563 if (dup_strings(&ret->env, &ret->nenv, 564 primary->env, primary->nenv) != 0) 565 goto alloc_fail; 566 } else if (additional->nenv) { 567 if (dup_strings(&ret->env, &ret->nenv, 568 additional->env, additional->nenv) != 0) 569 goto alloc_fail; 570 } 571 if (primary->npermitopen > 0) { 572 if (dup_strings(&ret->permitopen, &ret->npermitopen, 573 primary->permitopen, primary->npermitopen) != 0) 574 goto alloc_fail; 575 } else if (additional->npermitopen > 0) { 576 if (dup_strings(&ret->permitopen, &ret->npermitopen, 577 additional->permitopen, additional->npermitopen) != 0) 578 goto alloc_fail; 579 } 580 581 if (primary->npermitlisten > 0) { 582 if (dup_strings(&ret->permitlisten, &ret->npermitlisten, 583 primary->permitlisten, primary->npermitlisten) != 0) 584 goto alloc_fail; 585 } else if (additional->npermitlisten > 0) { 586 if (dup_strings(&ret->permitlisten, &ret->npermitlisten, 587 additional->permitlisten, additional->npermitlisten) != 0) 588 goto alloc_fail; 589 } 590 591 #define OPTFLAG_AND(x) ret->x = (primary->x == 1) && (additional->x == 1) 592 #define OPTFLAG_OR(x) ret->x = (primary->x == 1) || (additional->x == 1) 593 /* Permissive flags are logical-AND (i.e. must be set in both) */ 594 OPTFLAG_AND(permit_port_forwarding_flag); 595 OPTFLAG_AND(permit_agent_forwarding_flag); 596 OPTFLAG_AND(permit_x11_forwarding_flag); 597 OPTFLAG_AND(permit_pty_flag); 598 OPTFLAG_AND(permit_user_rc); 599 OPTFLAG_AND(no_require_user_presence); 600 /* Restrictive flags are logical-OR (i.e. must be set in either) */ 601 OPTFLAG_OR(require_verify); 602 #undef OPTFLAG_AND 603 604 /* Earliest expiry time should win */ 605 if (primary->valid_before != 0) 606 ret->valid_before = primary->valid_before; 607 if (additional->valid_before != 0 && 608 additional->valid_before < ret->valid_before) 609 ret->valid_before = additional->valid_before; 610 611 /* 612 * When both multiple forced-command are specified, only 613 * proceed if they are identical, otherwise fail. 614 */ 615 if (primary->force_command != NULL && 616 additional->force_command != NULL) { 617 if (strcmp(primary->force_command, 618 additional->force_command) == 0) { 619 /* ok */ 620 ret->force_command = strdup(primary->force_command); 621 if (ret->force_command == NULL) 622 goto alloc_fail; 623 } else { 624 errstr = "forced command options do not match"; 625 goto fail; 626 } 627 } else if (primary->force_command != NULL) { 628 if ((ret->force_command = strdup( 629 primary->force_command)) == NULL) 630 goto alloc_fail; 631 } else if (additional->force_command != NULL) { 632 if ((ret->force_command = strdup( 633 additional->force_command)) == NULL) 634 goto alloc_fail; 635 } 636 /* success */ 637 if (errstrp != NULL) 638 *errstrp = NULL; 639 return ret; 640 641 alloc_fail: 642 errstr = "memory allocation failed"; 643 fail: 644 if (errstrp != NULL) 645 *errstrp = errstr; 646 sshauthopt_free(ret); 647 return NULL; 648 } 649 650 /* 651 * Copy options 652 */ 653 struct sshauthopt * 654 sshauthopt_copy(const struct sshauthopt *orig) 655 { 656 struct sshauthopt *ret; 657 658 if ((ret = sshauthopt_new()) == NULL) 659 return NULL; 660 661 #define OPTSCALAR(x) ret->x = orig->x 662 OPTSCALAR(permit_port_forwarding_flag); 663 OPTSCALAR(permit_agent_forwarding_flag); 664 OPTSCALAR(permit_x11_forwarding_flag); 665 OPTSCALAR(permit_pty_flag); 666 OPTSCALAR(permit_user_rc); 667 OPTSCALAR(restricted); 668 OPTSCALAR(cert_authority); 669 OPTSCALAR(force_tun_device); 670 OPTSCALAR(valid_before); 671 OPTSCALAR(no_require_user_presence); 672 OPTSCALAR(require_verify); 673 #undef OPTSCALAR 674 #define OPTSTRING(x) \ 675 do { \ 676 if (orig->x != NULL && (ret->x = strdup(orig->x)) == NULL) { \ 677 sshauthopt_free(ret); \ 678 return NULL; \ 679 } \ 680 } while (0) 681 OPTSTRING(cert_principals); 682 OPTSTRING(force_command); 683 OPTSTRING(required_from_host_cert); 684 OPTSTRING(required_from_host_keys); 685 #undef OPTSTRING 686 687 if (dup_strings(&ret->env, &ret->nenv, orig->env, orig->nenv) != 0 || 688 dup_strings(&ret->permitopen, &ret->npermitopen, 689 orig->permitopen, orig->npermitopen) != 0 || 690 dup_strings(&ret->permitlisten, &ret->npermitlisten, 691 orig->permitlisten, orig->npermitlisten) != 0) { 692 sshauthopt_free(ret); 693 return NULL; 694 } 695 return ret; 696 } 697 698 static int 699 serialise_array(struct sshbuf *m, char **a, size_t n) 700 { 701 struct sshbuf *b; 702 size_t i; 703 int r = SSH_ERR_INTERNAL_ERROR; 704 705 if (n > INT_MAX) 706 return SSH_ERR_INTERNAL_ERROR; 707 708 if ((b = sshbuf_new()) == NULL) { 709 return SSH_ERR_ALLOC_FAIL; 710 } 711 for (i = 0; i < n; i++) { 712 if ((r = sshbuf_put_cstring(b, a[i])) != 0) 713 goto out; 714 } 715 if ((r = sshbuf_put_u32(m, n)) != 0 || 716 (r = sshbuf_put_stringb(m, b)) != 0) 717 goto out; 718 /* success */ 719 r = 0; 720 out: 721 sshbuf_free(b); 722 return r; 723 } 724 725 static int 726 deserialise_array(struct sshbuf *m, char ***ap, size_t *np) 727 { 728 char **a = NULL; 729 size_t i, n = 0; 730 struct sshbuf *b = NULL; 731 u_int tmp; 732 int r = SSH_ERR_INTERNAL_ERROR; 733 734 if ((r = sshbuf_get_u32(m, &tmp)) != 0 || 735 (r = sshbuf_froms(m, &b)) != 0) 736 goto out; 737 if (tmp > INT_MAX) { 738 r = SSH_ERR_INVALID_FORMAT; 739 goto out; 740 } 741 n = tmp; 742 if (n > 0 && (a = calloc(n, sizeof(*a))) == NULL) { 743 r = SSH_ERR_ALLOC_FAIL; 744 goto out; 745 } 746 for (i = 0; i < n; i++) { 747 if ((r = sshbuf_get_cstring(b, &a[i], NULL)) != 0) 748 goto out; 749 } 750 /* success */ 751 r = 0; 752 *ap = a; 753 a = NULL; 754 *np = n; 755 n = 0; 756 out: 757 if (a != NULL) { 758 for (i = 0; i < n; i++) 759 free(a[i]); 760 free(a); 761 } 762 sshbuf_free(b); 763 return r; 764 } 765 766 static int 767 serialise_nullable_string(struct sshbuf *m, const char *s) 768 { 769 int r; 770 771 if ((r = sshbuf_put_u8(m, s == NULL)) != 0 || 772 (r = sshbuf_put_cstring(m, s)) != 0) 773 return r; 774 return 0; 775 } 776 777 static int 778 deserialise_nullable_string(struct sshbuf *m, char **sp) 779 { 780 int r; 781 u_char flag; 782 783 *sp = NULL; 784 if ((r = sshbuf_get_u8(m, &flag)) != 0 || 785 (r = sshbuf_get_cstring(m, flag ? NULL : sp, NULL)) != 0) 786 return r; 787 return 0; 788 } 789 790 int 791 sshauthopt_serialise(const struct sshauthopt *opts, struct sshbuf *m, 792 int untrusted) 793 { 794 int r = SSH_ERR_INTERNAL_ERROR; 795 796 /* Flag options */ 797 if ((r = sshbuf_put_u8(m, opts->permit_port_forwarding_flag)) != 0 || 798 (r = sshbuf_put_u8(m, opts->permit_agent_forwarding_flag)) != 0 || 799 (r = sshbuf_put_u8(m, opts->permit_x11_forwarding_flag)) != 0 || 800 (r = sshbuf_put_u8(m, opts->permit_pty_flag)) != 0 || 801 (r = sshbuf_put_u8(m, opts->permit_user_rc)) != 0 || 802 (r = sshbuf_put_u8(m, opts->restricted)) != 0 || 803 (r = sshbuf_put_u8(m, opts->cert_authority)) != 0 || 804 (r = sshbuf_put_u8(m, opts->no_require_user_presence)) != 0 || 805 (r = sshbuf_put_u8(m, opts->require_verify)) != 0) 806 return r; 807 808 /* Simple integer options */ 809 if ((r = sshbuf_put_u64(m, opts->valid_before)) != 0) 810 return r; 811 812 /* tunnel number can be negative to indicate "unset" */ 813 if ((r = sshbuf_put_u8(m, opts->force_tun_device == -1)) != 0 || 814 (r = sshbuf_put_u32(m, (opts->force_tun_device < 0) ? 815 0 : (u_int)opts->force_tun_device)) != 0) 816 return r; 817 818 /* String options; these may be NULL */ 819 if ((r = serialise_nullable_string(m, 820 untrusted ? "yes" : opts->cert_principals)) != 0 || 821 (r = serialise_nullable_string(m, 822 untrusted ? "true" : opts->force_command)) != 0 || 823 (r = serialise_nullable_string(m, 824 untrusted ? NULL : opts->required_from_host_cert)) != 0 || 825 (r = serialise_nullable_string(m, 826 untrusted ? NULL : opts->required_from_host_keys)) != 0) 827 return r; 828 829 /* Array options */ 830 if ((r = serialise_array(m, opts->env, 831 untrusted ? 0 : opts->nenv)) != 0 || 832 (r = serialise_array(m, opts->permitopen, 833 untrusted ? 0 : opts->npermitopen)) != 0 || 834 (r = serialise_array(m, opts->permitlisten, 835 untrusted ? 0 : opts->npermitlisten)) != 0) 836 return r; 837 838 /* success */ 839 return 0; 840 } 841 842 int 843 sshauthopt_deserialise(struct sshbuf *m, struct sshauthopt **optsp) 844 { 845 struct sshauthopt *opts = NULL; 846 int r = SSH_ERR_INTERNAL_ERROR; 847 u_char f; 848 u_int tmp; 849 850 if ((opts = calloc(1, sizeof(*opts))) == NULL) 851 return SSH_ERR_ALLOC_FAIL; 852 853 /* Flag options */ 854 #define OPT_FLAG(x) \ 855 do { \ 856 if ((r = sshbuf_get_u8(m, &f)) != 0) \ 857 goto out; \ 858 opts->x = f; \ 859 } while (0) 860 OPT_FLAG(permit_port_forwarding_flag); 861 OPT_FLAG(permit_agent_forwarding_flag); 862 OPT_FLAG(permit_x11_forwarding_flag); 863 OPT_FLAG(permit_pty_flag); 864 OPT_FLAG(permit_user_rc); 865 OPT_FLAG(restricted); 866 OPT_FLAG(cert_authority); 867 OPT_FLAG(no_require_user_presence); 868 OPT_FLAG(require_verify); 869 #undef OPT_FLAG 870 871 /* Simple integer options */ 872 if ((r = sshbuf_get_u64(m, &opts->valid_before)) != 0) 873 goto out; 874 875 /* tunnel number can be negative to indicate "unset" */ 876 if ((r = sshbuf_get_u8(m, &f)) != 0 || 877 (r = sshbuf_get_u32(m, &tmp)) != 0) 878 goto out; 879 opts->force_tun_device = f ? -1 : (int)tmp; 880 881 /* String options may be NULL */ 882 if ((r = deserialise_nullable_string(m, &opts->cert_principals)) != 0 || 883 (r = deserialise_nullable_string(m, &opts->force_command)) != 0 || 884 (r = deserialise_nullable_string(m, 885 &opts->required_from_host_cert)) != 0 || 886 (r = deserialise_nullable_string(m, 887 &opts->required_from_host_keys)) != 0) 888 goto out; 889 890 /* Array options */ 891 if ((r = deserialise_array(m, &opts->env, &opts->nenv)) != 0 || 892 (r = deserialise_array(m, 893 &opts->permitopen, &opts->npermitopen)) != 0 || 894 (r = deserialise_array(m, 895 &opts->permitlisten, &opts->npermitlisten)) != 0) 896 goto out; 897 898 /* success */ 899 r = 0; 900 *optsp = opts; 901 opts = NULL; 902 out: 903 sshauthopt_free(opts); 904 return r; 905 } 906