auth-options.c revision 1.22
1 /* $NetBSD: auth-options.c,v 1.22 2020/02/27 00:24:40 christos Exp $ */ 2 /* $OpenBSD: auth-options.c,v 1.90 2019/11/25 00:54:23 djm Exp $ */ 3 /* 4 * Copyright (c) 2018 Damien Miller <djm (at) 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 1.22 2020/02/27 00:24:40 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("%s: sshbuf_fromb failed", __func__); 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("Unable to parse certificate options: %s", 93 ssh_err(r)); 94 goto out; 95 } 96 debug3("found certificate option \"%.100s\" len %zu", 97 name, sshbuf_len(data)); 98 found = 0; 99 if ((which & OPTIONS_EXTENSIONS) != 0) { 100 if (strcmp(name, "no-touch-required") == 0) { 101 opts->no_require_user_presence = 1; 102 found = 1; 103 } else if (strcmp(name, "permit-X11-forwarding") == 0) { 104 opts->permit_x11_forwarding_flag = 1; 105 found = 1; 106 } else if (strcmp(name, 107 "permit-agent-forwarding") == 0) { 108 opts->permit_agent_forwarding_flag = 1; 109 found = 1; 110 } else if (strcmp(name, 111 "permit-port-forwarding") == 0) { 112 opts->permit_port_forwarding_flag = 1; 113 found = 1; 114 } else if (strcmp(name, "permit-pty") == 0) { 115 opts->permit_pty_flag = 1; 116 found = 1; 117 } else if (strcmp(name, "permit-user-rc") == 0) { 118 opts->permit_user_rc = 1; 119 found = 1; 120 } 121 } 122 if (!found && (which & OPTIONS_CRITICAL) != 0) { 123 if (strcmp(name, "force-command") == 0) { 124 if ((r = sshbuf_get_cstring(data, &command, 125 NULL)) != 0) { 126 error("Unable to parse \"%s\" " 127 "section: %s", name, ssh_err(r)); 128 goto out; 129 } 130 if (opts->force_command != NULL) { 131 error("Certificate has multiple " 132 "force-command options"); 133 free(command); 134 goto out; 135 } 136 opts->force_command = command; 137 found = 1; 138 } 139 if (strcmp(name, "source-address") == 0) { 140 if ((r = sshbuf_get_cstring(data, &allowed, 141 NULL)) != 0) { 142 error("Unable to parse \"%s\" " 143 "section: %s", name, ssh_err(r)); 144 goto out; 145 } 146 if (opts->required_from_host_cert != NULL) { 147 error("Certificate has multiple " 148 "source-address options"); 149 free(allowed); 150 goto out; 151 } 152 /* Check syntax */ 153 if (addr_match_cidr_list(NULL, allowed) == -1) { 154 error("Certificate source-address " 155 "contents invalid"); 156 goto out; 157 } 158 opts->required_from_host_cert = allowed; 159 found = 1; 160 } 161 } 162 163 if (!found) { 164 if (crit) { 165 error("Certificate critical option \"%s\" " 166 "is not supported", name); 167 goto out; 168 } else { 169 logit("Certificate extension \"%s\" " 170 "is not supported", name); 171 } 172 } else if (sshbuf_len(data) != 0) { 173 error("Certificate option \"%s\" corrupt " 174 "(extra data)", name); 175 goto out; 176 } 177 free(name); 178 name = NULL; 179 } 180 /* successfully parsed all options */ 181 ret = 0; 182 183 out: 184 free(name); 185 sshbuf_free(data); 186 sshbuf_free(c); 187 return ret; 188 } 189 190 struct sshauthopt * 191 sshauthopt_new(void) 192 { 193 struct sshauthopt *ret; 194 195 if ((ret = calloc(1, sizeof(*ret))) == NULL) 196 return NULL; 197 ret->force_tun_device = -1; 198 return ret; 199 } 200 201 void 202 sshauthopt_free(struct sshauthopt *opts) 203 { 204 size_t i; 205 206 if (opts == NULL) 207 return; 208 209 free(opts->cert_principals); 210 free(opts->force_command); 211 free(opts->required_from_host_cert); 212 free(opts->required_from_host_keys); 213 214 for (i = 0; i < opts->nenv; i++) 215 free(opts->env[i]); 216 free(opts->env); 217 218 for (i = 0; i < opts->npermitopen; i++) 219 free(opts->permitopen[i]); 220 free(opts->permitopen); 221 222 for (i = 0; i < opts->npermitlisten; i++) 223 free(opts->permitlisten[i]); 224 free(opts->permitlisten); 225 226 explicit_bzero(opts, sizeof(*opts)); 227 free(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 = hpdelim(&cp); 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; 328 329 if (errstrp != NULL) 330 *errstrp = NULL; 331 if ((ret = sshauthopt_new_with_keys_defaults()) == NULL) 332 goto alloc_fail; 333 334 if (opts == NULL) 335 return ret; 336 337 while (*opts && *opts != ' ' && *opts != '\t') { 338 /* flag options */ 339 if ((r = opt_flag("restrict", 0, &opts)) != -1) { 340 ret->restricted = 1; 341 ret->permit_port_forwarding_flag = 0; 342 ret->permit_agent_forwarding_flag = 0; 343 ret->permit_x11_forwarding_flag = 0; 344 ret->permit_pty_flag = 0; 345 ret->permit_user_rc = 0; 346 } else if ((r = opt_flag("cert-authority", 0, &opts)) != -1) { 347 ret->cert_authority = r; 348 } else if ((r = opt_flag("port-forwarding", 1, &opts)) != -1) { 349 ret->permit_port_forwarding_flag = r == 1; 350 } else if ((r = opt_flag("agent-forwarding", 1, &opts)) != -1) { 351 ret->permit_agent_forwarding_flag = r == 1; 352 } else if ((r = opt_flag("x11-forwarding", 1, &opts)) != -1) { 353 ret->permit_x11_forwarding_flag = r == 1; 354 } else if ((r = opt_flag("touch-required", 1, &opts)) != -1) { 355 ret->no_require_user_presence = r != 1; /* NB. flip */ 356 } else if ((r = opt_flag("pty", 1, &opts)) != -1) { 357 ret->permit_pty_flag = r == 1; 358 } else if ((r = opt_flag("user-rc", 1, &opts)) != -1) { 359 ret->permit_user_rc = r == 1; 360 } else if (opt_match(&opts, "command")) { 361 if (ret->force_command != NULL) { 362 errstr = "multiple \"command\" clauses"; 363 goto fail; 364 } 365 ret->force_command = opt_dequote(&opts, &errstr); 366 if (ret->force_command == NULL) 367 goto fail; 368 } else if (opt_match(&opts, "principals")) { 369 if (ret->cert_principals != NULL) { 370 errstr = "multiple \"principals\" clauses"; 371 goto fail; 372 } 373 ret->cert_principals = opt_dequote(&opts, &errstr); 374 if (ret->cert_principals == NULL) 375 goto fail; 376 } else if (opt_match(&opts, "from")) { 377 if (ret->required_from_host_keys != NULL) { 378 errstr = "multiple \"from\" clauses"; 379 goto fail; 380 } 381 ret->required_from_host_keys = opt_dequote(&opts, 382 &errstr); 383 if (ret->required_from_host_keys == NULL) 384 goto fail; 385 } else if (opt_match(&opts, "expiry-time")) { 386 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 387 goto fail; 388 if (parse_absolute_time(opt, &valid_before) != 0 || 389 valid_before == 0) { 390 free(opt); 391 errstr = "invalid expires time"; 392 goto fail; 393 } 394 free(opt); 395 if (ret->valid_before == 0 || 396 valid_before < ret->valid_before) 397 ret->valid_before = valid_before; 398 } else if (opt_match(&opts, "environment")) { 399 if (ret->nenv > INT_MAX) { 400 errstr = "too many environment strings"; 401 goto fail; 402 } 403 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 404 goto fail; 405 /* env name must be alphanumeric and followed by '=' */ 406 if ((tmp = strchr(opt, '=')) == NULL) { 407 free(opt); 408 errstr = "invalid environment string"; 409 goto fail; 410 } 411 if ((cp = strdup(opt)) == NULL) 412 goto alloc_fail; 413 cp[tmp - opt] = '\0'; /* truncate at '=' */ 414 if (!valid_env_name(cp)) { 415 free(cp); 416 free(opt); 417 errstr = "invalid environment string"; 418 goto fail; 419 } 420 free(cp); 421 /* Append it. */ 422 oarray = ret->env; 423 if ((ret->env = recallocarray(ret->env, ret->nenv, 424 ret->nenv + 1, sizeof(*ret->env))) == NULL) { 425 free(opt); 426 ret->env = oarray; /* put it back for cleanup */ 427 goto alloc_fail; 428 } 429 ret->env[ret->nenv++] = opt; 430 } else if (opt_match(&opts, "permitopen")) { 431 if (handle_permit(&opts, 0, &ret->permitopen, 432 &ret->npermitopen, &errstr) != 0) 433 goto fail; 434 } else if (opt_match(&opts, "permitlisten")) { 435 if (handle_permit(&opts, 1, &ret->permitlisten, 436 &ret->npermitlisten, &errstr) != 0) 437 goto fail; 438 } else if (opt_match(&opts, "tunnel")) { 439 if ((opt = opt_dequote(&opts, &errstr)) == NULL) 440 goto fail; 441 ret->force_tun_device = a2tun(opt, NULL); 442 free(opt); 443 if (ret->force_tun_device == SSH_TUNID_ERR) { 444 errstr = "invalid tun device"; 445 goto fail; 446 } 447 } 448 /* 449 * Skip the comma, and move to the next option 450 * (or break out if there are no more). 451 */ 452 if (*opts == '\0' || *opts == ' ' || *opts == '\t') 453 break; /* End of options. */ 454 /* Anything other than a comma is an unknown option */ 455 if (*opts != ',') { 456 errstr = "unknown key option"; 457 goto fail; 458 } 459 opts++; 460 if (*opts == '\0') { 461 errstr = "unexpected end-of-options"; 462 goto fail; 463 } 464 } 465 466 /* success */ 467 if (errstrp != NULL) 468 *errstrp = NULL; 469 return ret; 470 471 alloc_fail: 472 errstr = "memory allocation failed"; 473 fail: 474 sshauthopt_free(ret); 475 if (errstrp != NULL) 476 *errstrp = errstr; 477 return NULL; 478 } 479 480 struct sshauthopt * 481 sshauthopt_from_cert(struct sshkey *k) 482 { 483 struct sshauthopt *ret; 484 485 if (k == NULL || !sshkey_type_is_cert(k->type) || k->cert == NULL || 486 k->cert->type != SSH2_CERT_TYPE_USER) 487 return NULL; 488 489 if ((ret = sshauthopt_new()) == NULL) 490 return NULL; 491 492 /* Handle options and critical extensions separately */ 493 if (cert_option_list(ret, k->cert->critical, 494 OPTIONS_CRITICAL, 1) == -1) { 495 sshauthopt_free(ret); 496 return NULL; 497 } 498 if (cert_option_list(ret, k->cert->extensions, 499 OPTIONS_EXTENSIONS, 0) == -1) { 500 sshauthopt_free(ret); 501 return NULL; 502 } 503 /* success */ 504 return ret; 505 } 506 507 /* 508 * Merges "additional" options to "primary" and returns the result. 509 * NB. Some options from primary have primacy. 510 */ 511 struct sshauthopt * 512 sshauthopt_merge(const struct sshauthopt *primary, 513 const struct sshauthopt *additional, const char **errstrp) 514 { 515 struct sshauthopt *ret; 516 const char *errstr = "internal error"; 517 const char *tmp; 518 519 if (errstrp != NULL) 520 *errstrp = NULL; 521 522 if ((ret = sshauthopt_new()) == NULL) 523 goto alloc_fail; 524 525 /* cert_authority and cert_principals are cleared in result */ 526 527 /* Prefer access lists from primary. */ 528 /* XXX err is both set and mismatch? */ 529 tmp = primary->required_from_host_cert; 530 if (tmp == NULL) 531 tmp = additional->required_from_host_cert; 532 if (tmp != NULL && (ret->required_from_host_cert = strdup(tmp)) == NULL) 533 goto alloc_fail; 534 tmp = primary->required_from_host_keys; 535 if (tmp == NULL) 536 tmp = additional->required_from_host_keys; 537 if (tmp != NULL && (ret->required_from_host_keys = strdup(tmp)) == NULL) 538 goto alloc_fail; 539 540 /* 541 * force_tun_device, permitopen/permitlisten and environment all 542 * prefer the primary. 543 */ 544 ret->force_tun_device = primary->force_tun_device; 545 if (ret->force_tun_device == -1) 546 ret->force_tun_device = additional->force_tun_device; 547 if (primary->nenv > 0) { 548 if (dup_strings(&ret->env, &ret->nenv, 549 primary->env, primary->nenv) != 0) 550 goto alloc_fail; 551 } else if (additional->nenv) { 552 if (dup_strings(&ret->env, &ret->nenv, 553 additional->env, additional->nenv) != 0) 554 goto alloc_fail; 555 } 556 if (primary->npermitopen > 0) { 557 if (dup_strings(&ret->permitopen, &ret->npermitopen, 558 primary->permitopen, primary->npermitopen) != 0) 559 goto alloc_fail; 560 } else if (additional->npermitopen > 0) { 561 if (dup_strings(&ret->permitopen, &ret->npermitopen, 562 additional->permitopen, additional->npermitopen) != 0) 563 goto alloc_fail; 564 } 565 566 if (primary->npermitlisten > 0) { 567 if (dup_strings(&ret->permitlisten, &ret->npermitlisten, 568 primary->permitlisten, primary->npermitlisten) != 0) 569 goto alloc_fail; 570 } else if (additional->npermitlisten > 0) { 571 if (dup_strings(&ret->permitlisten, &ret->npermitlisten, 572 additional->permitlisten, additional->npermitlisten) != 0) 573 goto alloc_fail; 574 } 575 576 #define OPTFLAG_AND(x) ret->x = (primary->x == 1) && (additional->x == 1) 577 /* Permissive flags are logical-AND (i.e. must be set in both) */ 578 OPTFLAG_AND(permit_port_forwarding_flag); 579 OPTFLAG_AND(permit_agent_forwarding_flag); 580 OPTFLAG_AND(permit_x11_forwarding_flag); 581 OPTFLAG_AND(permit_pty_flag); 582 OPTFLAG_AND(permit_user_rc); 583 OPTFLAG_AND(no_require_user_presence); 584 #undef OPTFLAG_AND 585 586 /* Earliest expiry time should win */ 587 if (primary->valid_before != 0) 588 ret->valid_before = primary->valid_before; 589 if (additional->valid_before != 0 && 590 additional->valid_before < ret->valid_before) 591 ret->valid_before = additional->valid_before; 592 593 /* 594 * When both multiple forced-command are specified, only 595 * proceed if they are identical, otherwise fail. 596 */ 597 if (primary->force_command != NULL && 598 additional->force_command != NULL) { 599 if (strcmp(primary->force_command, 600 additional->force_command) == 0) { 601 /* ok */ 602 ret->force_command = strdup(primary->force_command); 603 if (ret->force_command == NULL) 604 goto alloc_fail; 605 } else { 606 errstr = "forced command options do not match"; 607 goto fail; 608 } 609 } else if (primary->force_command != NULL) { 610 if ((ret->force_command = strdup( 611 primary->force_command)) == NULL) 612 goto alloc_fail; 613 } else if (additional->force_command != NULL) { 614 if ((ret->force_command = strdup( 615 additional->force_command)) == NULL) 616 goto alloc_fail; 617 } 618 /* success */ 619 if (errstrp != NULL) 620 *errstrp = NULL; 621 return ret; 622 623 alloc_fail: 624 errstr = "memory allocation failed"; 625 fail: 626 if (errstrp != NULL) 627 *errstrp = errstr; 628 sshauthopt_free(ret); 629 return NULL; 630 } 631 632 /* 633 * Copy options 634 */ 635 struct sshauthopt * 636 sshauthopt_copy(const struct sshauthopt *orig) 637 { 638 struct sshauthopt *ret; 639 640 if ((ret = sshauthopt_new()) == NULL) 641 return NULL; 642 643 #define OPTSCALAR(x) ret->x = orig->x 644 OPTSCALAR(permit_port_forwarding_flag); 645 OPTSCALAR(permit_agent_forwarding_flag); 646 OPTSCALAR(permit_x11_forwarding_flag); 647 OPTSCALAR(permit_pty_flag); 648 OPTSCALAR(permit_user_rc); 649 OPTSCALAR(restricted); 650 OPTSCALAR(cert_authority); 651 OPTSCALAR(force_tun_device); 652 OPTSCALAR(valid_before); 653 OPTSCALAR(no_require_user_presence); 654 #undef OPTSCALAR 655 #define OPTSTRING(x) \ 656 do { \ 657 if (orig->x != NULL && (ret->x = strdup(orig->x)) == NULL) { \ 658 sshauthopt_free(ret); \ 659 return NULL; \ 660 } \ 661 } while (0) 662 OPTSTRING(cert_principals); 663 OPTSTRING(force_command); 664 OPTSTRING(required_from_host_cert); 665 OPTSTRING(required_from_host_keys); 666 #undef OPTSTRING 667 668 if (dup_strings(&ret->env, &ret->nenv, orig->env, orig->nenv) != 0 || 669 dup_strings(&ret->permitopen, &ret->npermitopen, 670 orig->permitopen, orig->npermitopen) != 0 || 671 dup_strings(&ret->permitlisten, &ret->npermitlisten, 672 orig->permitlisten, orig->npermitlisten) != 0) { 673 sshauthopt_free(ret); 674 return NULL; 675 } 676 return ret; 677 } 678 679 static int 680 serialise_array(struct sshbuf *m, char **a, size_t n) 681 { 682 struct sshbuf *b; 683 size_t i; 684 int r; 685 686 if (n > INT_MAX) 687 return SSH_ERR_INTERNAL_ERROR; 688 689 if ((b = sshbuf_new()) == NULL) { 690 return SSH_ERR_ALLOC_FAIL; 691 } 692 for (i = 0; i < n; i++) { 693 if ((r = sshbuf_put_cstring(b, a[i])) != 0) { 694 sshbuf_free(b); 695 return r; 696 } 697 } 698 if ((r = sshbuf_put_u32(m, n)) != 0 || 699 (r = sshbuf_put_stringb(m, b)) != 0) { 700 sshbuf_free(b); 701 return r; 702 } 703 /* success */ 704 return 0; 705 } 706 707 static int 708 deserialise_array(struct sshbuf *m, char ***ap, size_t *np) 709 { 710 char **a = NULL; 711 size_t i, n = 0; 712 struct sshbuf *b = NULL; 713 u_int tmp; 714 int r = SSH_ERR_INTERNAL_ERROR; 715 716 if ((r = sshbuf_get_u32(m, &tmp)) != 0 || 717 (r = sshbuf_froms(m, &b)) != 0) 718 goto out; 719 if (tmp > INT_MAX) { 720 r = SSH_ERR_INVALID_FORMAT; 721 goto out; 722 } 723 n = tmp; 724 if (n > 0 && (a = calloc(n, sizeof(*a))) == NULL) { 725 r = SSH_ERR_ALLOC_FAIL; 726 goto out; 727 } 728 for (i = 0; i < n; i++) { 729 if ((r = sshbuf_get_cstring(b, &a[i], NULL)) != 0) 730 goto out; 731 } 732 /* success */ 733 r = 0; 734 *ap = a; 735 a = NULL; 736 *np = n; 737 n = 0; 738 out: 739 for (i = 0; i < n; i++) 740 free(a[i]); 741 free(a); 742 sshbuf_free(b); 743 return r; 744 } 745 746 static int 747 serialise_nullable_string(struct sshbuf *m, const char *s) 748 { 749 int r; 750 751 if ((r = sshbuf_put_u8(m, s == NULL)) != 0 || 752 (r = sshbuf_put_cstring(m, s)) != 0) 753 return r; 754 return 0; 755 } 756 757 static int 758 deserialise_nullable_string(struct sshbuf *m, char **sp) 759 { 760 int r; 761 u_char flag; 762 763 *sp = NULL; 764 if ((r = sshbuf_get_u8(m, &flag)) != 0 || 765 (r = sshbuf_get_cstring(m, flag ? NULL : sp, NULL)) != 0) 766 return r; 767 return 0; 768 } 769 770 int 771 sshauthopt_serialise(const struct sshauthopt *opts, struct sshbuf *m, 772 int untrusted) 773 { 774 int r = SSH_ERR_INTERNAL_ERROR; 775 776 /* Flag options */ 777 if ((r = sshbuf_put_u8(m, opts->permit_port_forwarding_flag)) != 0 || 778 (r = sshbuf_put_u8(m, opts->permit_agent_forwarding_flag)) != 0 || 779 (r = sshbuf_put_u8(m, opts->permit_x11_forwarding_flag)) != 0 || 780 (r = sshbuf_put_u8(m, opts->permit_pty_flag)) != 0 || 781 (r = sshbuf_put_u8(m, opts->permit_user_rc)) != 0 || 782 (r = sshbuf_put_u8(m, opts->restricted)) != 0 || 783 (r = sshbuf_put_u8(m, opts->cert_authority)) != 0 || 784 (r = sshbuf_put_u8(m, opts->no_require_user_presence)) != 0) 785 return r; 786 787 /* Simple integer options */ 788 if ((r = sshbuf_put_u64(m, opts->valid_before)) != 0) 789 return r; 790 791 /* tunnel number can be negative to indicate "unset" */ 792 if ((r = sshbuf_put_u8(m, opts->force_tun_device == -1)) != 0 || 793 (r = sshbuf_put_u32(m, (opts->force_tun_device < 0) ? 794 0 : (u_int)opts->force_tun_device)) != 0) 795 return r; 796 797 /* String options; these may be NULL */ 798 if ((r = serialise_nullable_string(m, 799 untrusted ? "yes" : opts->cert_principals)) != 0 || 800 (r = serialise_nullable_string(m, 801 untrusted ? "true" : opts->force_command)) != 0 || 802 (r = serialise_nullable_string(m, 803 untrusted ? NULL : opts->required_from_host_cert)) != 0 || 804 (r = serialise_nullable_string(m, 805 untrusted ? NULL : opts->required_from_host_keys)) != 0) 806 return r; 807 808 /* Array options */ 809 if ((r = serialise_array(m, opts->env, 810 untrusted ? 0 : opts->nenv)) != 0 || 811 (r = serialise_array(m, opts->permitopen, 812 untrusted ? 0 : opts->npermitopen)) != 0 || 813 (r = serialise_array(m, opts->permitlisten, 814 untrusted ? 0 : opts->npermitlisten)) != 0) 815 return r; 816 817 /* success */ 818 return 0; 819 } 820 821 int 822 sshauthopt_deserialise(struct sshbuf *m, struct sshauthopt **optsp) 823 { 824 struct sshauthopt *opts = NULL; 825 int r = SSH_ERR_INTERNAL_ERROR; 826 u_char f; 827 u_int tmp; 828 829 if ((opts = calloc(1, sizeof(*opts))) == NULL) 830 return SSH_ERR_ALLOC_FAIL; 831 832 /* Flag options */ 833 #define OPT_FLAG(x) \ 834 do { \ 835 if ((r = sshbuf_get_u8(m, &f)) != 0) \ 836 goto out; \ 837 opts->x = f; \ 838 } while (0) 839 OPT_FLAG(permit_port_forwarding_flag); 840 OPT_FLAG(permit_agent_forwarding_flag); 841 OPT_FLAG(permit_x11_forwarding_flag); 842 OPT_FLAG(permit_pty_flag); 843 OPT_FLAG(permit_user_rc); 844 OPT_FLAG(restricted); 845 OPT_FLAG(cert_authority); 846 OPT_FLAG(no_require_user_presence); 847 #undef OPT_FLAG 848 849 /* Simple integer options */ 850 if ((r = sshbuf_get_u64(m, &opts->valid_before)) != 0) 851 goto out; 852 853 /* tunnel number can be negative to indicate "unset" */ 854 if ((r = sshbuf_get_u8(m, &f)) != 0 || 855 (r = sshbuf_get_u32(m, &tmp)) != 0) 856 goto out; 857 opts->force_tun_device = f ? -1 : (int)tmp; 858 859 /* String options may be NULL */ 860 if ((r = deserialise_nullable_string(m, &opts->cert_principals)) != 0 || 861 (r = deserialise_nullable_string(m, &opts->force_command)) != 0 || 862 (r = deserialise_nullable_string(m, 863 &opts->required_from_host_cert)) != 0 || 864 (r = deserialise_nullable_string(m, 865 &opts->required_from_host_keys)) != 0) 866 goto out; 867 868 /* Array options */ 869 if ((r = deserialise_array(m, &opts->env, &opts->nenv)) != 0 || 870 (r = deserialise_array(m, 871 &opts->permitopen, &opts->npermitopen)) != 0 || 872 (r = deserialise_array(m, 873 &opts->permitlisten, &opts->npermitlisten)) != 0) 874 goto out; 875 876 /* success */ 877 r = 0; 878 *optsp = opts; 879 opts = NULL; 880 out: 881 sshauthopt_free(opts); 882 return r; 883 } 884
Indexes created Sat May 02 00:23:24 UTC 2026