1 /* $OpenBSD: sshkey.c,v 1.155 2025/10/03 00:08:02 djm Exp $ */ 2 /* 3 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 4 * Copyright (c) 2008 Alexander von Gernler. All rights reserved. 5 * Copyright (c) 2010,2011 Damien Miller. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include "includes.h" 29 30 #include <sys/types.h> 31 #include <sys/mman.h> 32 #include <netinet/in.h> 33 34 #ifdef WITH_OPENSSL 35 #include <openssl/bn.h> 36 #include <openssl/evp.h> 37 #include <openssl/err.h> 38 #include <openssl/pem.h> 39 #endif 40 41 #include "crypto_api.h" 42 43 #include <errno.h> 44 #include <limits.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <resolv.h> 49 #include <time.h> 50 #include <util.h> 51 52 #include "ssh2.h" 53 #include "ssherr.h" 54 #include "misc.h" 55 #include "sshbuf.h" 56 #include "cipher.h" 57 #include "digest.h" 58 #define SSHKEY_INTERNAL 59 #include "sshkey.h" 60 #include "match.h" 61 #include "ssh-sk.h" 62 #include "ssh-pkcs11.h" 63 64 #include "openbsd-compat/openssl-compat.h" 65 66 /* openssh private key file format */ 67 #define MARK_BEGIN "-----BEGIN OPENSSH PRIVATE KEY-----\n" 68 #define MARK_END "-----END OPENSSH PRIVATE KEY-----\n" 69 #define MARK_BEGIN_LEN (sizeof(MARK_BEGIN) - 1) 70 #define MARK_END_LEN (sizeof(MARK_END) - 1) 71 #define KDFNAME "bcrypt" 72 #define AUTH_MAGIC "openssh-key-v1" 73 #define SALT_LEN 16 74 #define DEFAULT_CIPHERNAME "aes256-ctr" 75 #define DEFAULT_ROUNDS 24 76 77 /* 78 * Constants relating to "shielding" support; protection of keys expected 79 * to remain in memory for long durations 80 */ 81 #define SSHKEY_SHIELD_PREKEY_LEN (16 * 1024) 82 #define SSHKEY_SHIELD_CIPHER "aes256-ctr" /* XXX want AES-EME* */ 83 #define SSHKEY_SHIELD_PREKEY_HASH SSH_DIGEST_SHA512 84 85 static int sshkey_from_blob_internal(struct sshbuf *buf, 86 struct sshkey **keyp, int allow_cert); 87 88 /* Supported key types */ 89 extern const struct sshkey_impl sshkey_ed25519_impl; 90 extern const struct sshkey_impl sshkey_ed25519_cert_impl; 91 extern const struct sshkey_impl sshkey_ed25519_sk_impl; 92 extern const struct sshkey_impl sshkey_ed25519_sk_cert_impl; 93 #ifdef WITH_OPENSSL 94 # ifdef OPENSSL_HAS_ECC 95 # ifdef ENABLE_SK 96 extern const struct sshkey_impl sshkey_ecdsa_sk_impl; 97 extern const struct sshkey_impl sshkey_ecdsa_sk_cert_impl; 98 extern const struct sshkey_impl sshkey_ecdsa_sk_webauthn_impl; 99 # endif /* ENABLE_SK */ 100 extern const struct sshkey_impl sshkey_ecdsa_nistp256_impl; 101 extern const struct sshkey_impl sshkey_ecdsa_nistp256_cert_impl; 102 extern const struct sshkey_impl sshkey_ecdsa_nistp384_impl; 103 extern const struct sshkey_impl sshkey_ecdsa_nistp384_cert_impl; 104 # ifdef OPENSSL_HAS_NISTP521 105 extern const struct sshkey_impl sshkey_ecdsa_nistp521_impl; 106 extern const struct sshkey_impl sshkey_ecdsa_nistp521_cert_impl; 107 # endif /* OPENSSL_HAS_NISTP521 */ 108 # endif /* OPENSSL_HAS_ECC */ 109 extern const struct sshkey_impl sshkey_rsa_impl; 110 extern const struct sshkey_impl sshkey_rsa_cert_impl; 111 extern const struct sshkey_impl sshkey_rsa_sha256_impl; 112 extern const struct sshkey_impl sshkey_rsa_sha256_cert_impl; 113 extern const struct sshkey_impl sshkey_rsa_sha512_impl; 114 extern const struct sshkey_impl sshkey_rsa_sha512_cert_impl; 115 #endif /* WITH_OPENSSL */ 116 117 const struct sshkey_impl * const keyimpls[] = { 118 &sshkey_ed25519_impl, 119 &sshkey_ed25519_cert_impl, 120 #ifdef ENABLE_SK 121 &sshkey_ed25519_sk_impl, 122 &sshkey_ed25519_sk_cert_impl, 123 #endif 124 #ifdef WITH_OPENSSL 125 # ifdef OPENSSL_HAS_ECC 126 &sshkey_ecdsa_nistp256_impl, 127 &sshkey_ecdsa_nistp256_cert_impl, 128 &sshkey_ecdsa_nistp384_impl, 129 &sshkey_ecdsa_nistp384_cert_impl, 130 # ifdef OPENSSL_HAS_NISTP521 131 &sshkey_ecdsa_nistp521_impl, 132 &sshkey_ecdsa_nistp521_cert_impl, 133 # endif /* OPENSSL_HAS_NISTP521 */ 134 # ifdef ENABLE_SK 135 &sshkey_ecdsa_sk_impl, 136 &sshkey_ecdsa_sk_cert_impl, 137 &sshkey_ecdsa_sk_webauthn_impl, 138 # endif /* ENABLE_SK */ 139 # endif /* OPENSSL_HAS_ECC */ 140 &sshkey_rsa_impl, 141 &sshkey_rsa_cert_impl, 142 &sshkey_rsa_sha256_impl, 143 &sshkey_rsa_sha256_cert_impl, 144 &sshkey_rsa_sha512_impl, 145 &sshkey_rsa_sha512_cert_impl, 146 #endif /* WITH_OPENSSL */ 147 NULL 148 }; 149 150 static const struct sshkey_impl * 151 sshkey_impl_from_type(int type) 152 { 153 int i; 154 155 for (i = 0; keyimpls[i] != NULL; i++) { 156 if (keyimpls[i]->type == type) 157 return keyimpls[i]; 158 } 159 return NULL; 160 } 161 162 static const struct sshkey_impl * 163 sshkey_impl_from_type_nid(int type, int nid) 164 { 165 int i; 166 167 for (i = 0; keyimpls[i] != NULL; i++) { 168 if (keyimpls[i]->type == type && 169 (keyimpls[i]->nid == 0 || keyimpls[i]->nid == nid)) 170 return keyimpls[i]; 171 } 172 return NULL; 173 } 174 175 static const struct sshkey_impl * 176 sshkey_impl_from_key(const struct sshkey *k) 177 { 178 if (k == NULL) 179 return NULL; 180 return sshkey_impl_from_type_nid(k->type, k->ecdsa_nid); 181 } 182 183 const char * 184 sshkey_type(const struct sshkey *k) 185 { 186 const struct sshkey_impl *impl; 187 188 if ((impl = sshkey_impl_from_key(k)) == NULL) 189 return "unknown"; 190 return impl->shortname; 191 } 192 193 static const char * 194 sshkey_ssh_name_from_type_nid(int type, int nid) 195 { 196 const struct sshkey_impl *impl; 197 198 if ((impl = sshkey_impl_from_type_nid(type, nid)) == NULL) 199 return "ssh-unknown"; 200 return impl->name; 201 } 202 203 int 204 sshkey_type_is_cert(int type) 205 { 206 const struct sshkey_impl *impl; 207 208 if ((impl = sshkey_impl_from_type(type)) == NULL) 209 return 0; 210 return impl->cert; 211 } 212 213 const char * 214 sshkey_ssh_name(const struct sshkey *k) 215 { 216 return sshkey_ssh_name_from_type_nid(k->type, k->ecdsa_nid); 217 } 218 219 const char * 220 sshkey_ssh_name_plain(const struct sshkey *k) 221 { 222 return sshkey_ssh_name_from_type_nid(sshkey_type_plain(k->type), 223 k->ecdsa_nid); 224 } 225 226 static int 227 type_from_name(const char *name, int allow_short) 228 { 229 int i; 230 const struct sshkey_impl *impl; 231 232 for (i = 0; keyimpls[i] != NULL; i++) { 233 impl = keyimpls[i]; 234 if (impl->name != NULL && strcmp(name, impl->name) == 0) 235 return impl->type; 236 /* Only allow shortname matches for plain key types */ 237 if (allow_short && !impl->cert && impl->shortname != NULL && 238 strcasecmp(impl->shortname, name) == 0) 239 return impl->type; 240 } 241 return KEY_UNSPEC; 242 } 243 244 int 245 sshkey_type_from_name(const char *name) 246 { 247 return type_from_name(name, 0); 248 } 249 250 int 251 sshkey_type_from_shortname(const char *name) 252 { 253 return type_from_name(name, 1); 254 } 255 256 static int 257 key_type_is_ecdsa_variant(int type) 258 { 259 switch (type) { 260 case KEY_ECDSA: 261 case KEY_ECDSA_CERT: 262 case KEY_ECDSA_SK: 263 case KEY_ECDSA_SK_CERT: 264 return 1; 265 } 266 return 0; 267 } 268 269 int 270 sshkey_ecdsa_nid_from_name(const char *name) 271 { 272 int i; 273 274 for (i = 0; keyimpls[i] != NULL; i++) { 275 if (!key_type_is_ecdsa_variant(keyimpls[i]->type)) 276 continue; 277 if (keyimpls[i]->name != NULL && 278 strcmp(name, keyimpls[i]->name) == 0) 279 return keyimpls[i]->nid; 280 } 281 return -1; 282 } 283 284 int 285 sshkey_match_keyname_to_sigalgs(const char *keyname, const char *sigalgs) 286 { 287 int ktype; 288 289 if (sigalgs == NULL || *sigalgs == '\0' || 290 (ktype = sshkey_type_from_name(keyname)) == KEY_UNSPEC) 291 return 0; 292 else if (ktype == KEY_RSA) { 293 return match_pattern_list("ssh-rsa", sigalgs, 0) == 1 || 294 match_pattern_list("rsa-sha2-256", sigalgs, 0) == 1 || 295 match_pattern_list("rsa-sha2-512", sigalgs, 0) == 1; 296 } else if (ktype == KEY_RSA_CERT) { 297 return match_pattern_list("ssh-rsa-cert-v01@openssh.com", 298 sigalgs, 0) == 1 || 299 match_pattern_list("rsa-sha2-256-cert-v01@openssh.com", 300 sigalgs, 0) == 1 || 301 match_pattern_list("rsa-sha2-512-cert-v01@openssh.com", 302 sigalgs, 0) == 1; 303 } else 304 return match_pattern_list(keyname, sigalgs, 0) == 1; 305 } 306 307 char * 308 sshkey_alg_list(int certs_only, int plain_only, int include_sigonly, char sep) 309 { 310 char *ret = NULL; 311 size_t i; 312 const struct sshkey_impl *impl; 313 char sep_str[2] = {sep, '\0'}; 314 315 for (i = 0; keyimpls[i] != NULL; i++) { 316 impl = keyimpls[i]; 317 if (impl->name == NULL) 318 continue; 319 if (!include_sigonly && impl->sigonly) 320 continue; 321 if ((certs_only && !impl->cert) || (plain_only && impl->cert)) 322 continue; 323 xextendf(&ret, sep_str, "%s", impl->name); 324 } 325 return ret; 326 } 327 328 int 329 sshkey_names_valid2(const char *names, int allow_wildcard, int plain_only) 330 { 331 char *s, *cp, *p; 332 const struct sshkey_impl *impl; 333 int i, type; 334 335 if (names == NULL || strcmp(names, "") == 0) 336 return 0; 337 if ((s = cp = strdup(names)) == NULL) 338 return 0; 339 for ((p = strsep(&cp, ",")); p && *p != '\0'; 340 (p = strsep(&cp, ","))) { 341 type = sshkey_type_from_name(p); 342 if (type == KEY_UNSPEC) { 343 if (allow_wildcard) { 344 /* 345 * Try matching key types against the string. 346 * If any has a positive or negative match then 347 * the component is accepted. 348 */ 349 impl = NULL; 350 for (i = 0; keyimpls[i] != NULL; i++) { 351 if (match_pattern_list( 352 keyimpls[i]->name, p, 0) != 0) { 353 impl = keyimpls[i]; 354 break; 355 } 356 } 357 if (impl != NULL) 358 continue; 359 } 360 free(s); 361 return 0; 362 } else if (plain_only && sshkey_type_is_cert(type)) { 363 free(s); 364 return 0; 365 } 366 } 367 free(s); 368 return 1; 369 } 370 371 u_int 372 sshkey_size(const struct sshkey *k) 373 { 374 const struct sshkey_impl *impl; 375 376 if ((impl = sshkey_impl_from_key(k)) == NULL) 377 return 0; 378 if (impl->funcs->size != NULL) 379 return impl->funcs->size(k); 380 return impl->keybits; 381 } 382 383 static int 384 sshkey_type_is_valid_ca(int type) 385 { 386 const struct sshkey_impl *impl; 387 388 if ((impl = sshkey_impl_from_type(type)) == NULL) 389 return 0; 390 /* All non-certificate types may act as CAs */ 391 return !impl->cert; 392 } 393 394 int 395 sshkey_is_cert(const struct sshkey *k) 396 { 397 if (k == NULL) 398 return 0; 399 return sshkey_type_is_cert(k->type); 400 } 401 402 int 403 sshkey_is_sk(const struct sshkey *k) 404 { 405 if (k == NULL) 406 return 0; 407 switch (sshkey_type_plain(k->type)) { 408 case KEY_ECDSA_SK: 409 case KEY_ED25519_SK: 410 return 1; 411 default: 412 return 0; 413 } 414 } 415 416 /* Return the cert-less equivalent to a certified key type */ 417 int 418 sshkey_type_plain(int type) 419 { 420 switch (type) { 421 case KEY_RSA_CERT: 422 return KEY_RSA; 423 case KEY_ECDSA_CERT: 424 return KEY_ECDSA; 425 case KEY_ECDSA_SK_CERT: 426 return KEY_ECDSA_SK; 427 case KEY_ED25519_CERT: 428 return KEY_ED25519; 429 case KEY_ED25519_SK_CERT: 430 return KEY_ED25519_SK; 431 default: 432 return type; 433 } 434 } 435 436 /* Return the cert equivalent to a plain key type */ 437 static int 438 sshkey_type_certified(int type) 439 { 440 switch (type) { 441 case KEY_RSA: 442 return KEY_RSA_CERT; 443 case KEY_ECDSA: 444 return KEY_ECDSA_CERT; 445 case KEY_ECDSA_SK: 446 return KEY_ECDSA_SK_CERT; 447 case KEY_ED25519: 448 return KEY_ED25519_CERT; 449 case KEY_ED25519_SK: 450 return KEY_ED25519_SK_CERT; 451 default: 452 return -1; 453 } 454 } 455 456 #ifdef WITH_OPENSSL 457 static const EVP_MD * 458 ssh_digest_to_md(int hash_alg) 459 { 460 switch (hash_alg) { 461 case SSH_DIGEST_SHA1: 462 return EVP_sha1(); 463 case SSH_DIGEST_SHA256: 464 return EVP_sha256(); 465 case SSH_DIGEST_SHA384: 466 return EVP_sha384(); 467 case SSH_DIGEST_SHA512: 468 return EVP_sha512(); 469 } 470 return NULL; 471 } 472 473 int 474 sshkey_pkey_digest_sign(EVP_PKEY *pkey, int hash_alg, u_char **sigp, 475 size_t *lenp, const u_char *data, size_t datalen) 476 { 477 EVP_MD_CTX *ctx = NULL; 478 u_char *sig = NULL; 479 int ret; 480 size_t slen; 481 const EVP_MD *evpmd; 482 483 *sigp = NULL; 484 *lenp = 0; 485 486 slen = EVP_PKEY_size(pkey); 487 if (slen <= 0 || slen > SSHBUF_MAX_BIGNUM || 488 (evpmd = ssh_digest_to_md(hash_alg)) == NULL) 489 return SSH_ERR_INVALID_ARGUMENT; 490 491 if ((sig = malloc(slen)) == NULL) 492 return SSH_ERR_ALLOC_FAIL; 493 494 if ((ctx = EVP_MD_CTX_new()) == NULL) { 495 ret = SSH_ERR_ALLOC_FAIL; 496 goto out; 497 } 498 if (EVP_DigestSignInit(ctx, NULL, evpmd, NULL, pkey) != 1 || 499 EVP_DigestSign(ctx, sig, &slen, data, datalen) != 1) { 500 ret = SSH_ERR_LIBCRYPTO_ERROR; 501 goto out; 502 } 503 504 *sigp = sig; 505 *lenp = slen; 506 /* Now owned by the caller */ 507 sig = NULL; 508 ret = 0; 509 510 out: 511 EVP_MD_CTX_free(ctx); 512 free(sig); 513 return ret; 514 } 515 516 int 517 sshkey_pkey_digest_verify(EVP_PKEY *pkey, int hash_alg, const u_char *data, 518 size_t datalen, u_char *sigbuf, size_t siglen) 519 { 520 EVP_MD_CTX *ctx = NULL; 521 int ret = SSH_ERR_INTERNAL_ERROR; 522 const EVP_MD *evpmd; 523 524 if ((evpmd = ssh_digest_to_md(hash_alg)) == NULL) 525 return SSH_ERR_INVALID_ARGUMENT; 526 if ((ctx = EVP_MD_CTX_new()) == NULL) 527 return SSH_ERR_ALLOC_FAIL; 528 if (EVP_DigestVerifyInit(ctx, NULL, evpmd, NULL, pkey) != 1) { 529 ret = SSH_ERR_LIBCRYPTO_ERROR; 530 goto out; 531 } 532 switch (EVP_DigestVerify(ctx, sigbuf, siglen, data, datalen)) { 533 case 1: 534 ret = 0; 535 break; 536 case 0: 537 ret = SSH_ERR_SIGNATURE_INVALID; 538 break; 539 default: 540 ret = SSH_ERR_LIBCRYPTO_ERROR; 541 break; 542 } 543 544 out: 545 EVP_MD_CTX_free(ctx); 546 return ret; 547 } 548 549 /* XXX: these are really begging for a table-driven approach */ 550 int 551 sshkey_curve_name_to_nid(const char *name) 552 { 553 if (strcmp(name, "nistp256") == 0) 554 return NID_X9_62_prime256v1; 555 else if (strcmp(name, "nistp384") == 0) 556 return NID_secp384r1; 557 # ifdef OPENSSL_HAS_NISTP521 558 else if (strcmp(name, "nistp521") == 0) 559 return NID_secp521r1; 560 # endif /* OPENSSL_HAS_NISTP521 */ 561 else 562 return -1; 563 } 564 565 u_int 566 sshkey_curve_nid_to_bits(int nid) 567 { 568 switch (nid) { 569 case NID_X9_62_prime256v1: 570 return 256; 571 case NID_secp384r1: 572 return 384; 573 # ifdef OPENSSL_HAS_NISTP521 574 case NID_secp521r1: 575 return 521; 576 # endif /* OPENSSL_HAS_NISTP521 */ 577 default: 578 return 0; 579 } 580 } 581 582 int 583 sshkey_ecdsa_bits_to_nid(int bits) 584 { 585 switch (bits) { 586 case 256: 587 return NID_X9_62_prime256v1; 588 case 384: 589 return NID_secp384r1; 590 # ifdef OPENSSL_HAS_NISTP521 591 case 521: 592 return NID_secp521r1; 593 # endif /* OPENSSL_HAS_NISTP521 */ 594 default: 595 return -1; 596 } 597 } 598 599 const char * 600 sshkey_curve_nid_to_name(int nid) 601 { 602 switch (nid) { 603 case NID_X9_62_prime256v1: 604 return "nistp256"; 605 case NID_secp384r1: 606 return "nistp384"; 607 # ifdef OPENSSL_HAS_NISTP521 608 case NID_secp521r1: 609 return "nistp521"; 610 # endif /* OPENSSL_HAS_NISTP521 */ 611 default: 612 return NULL; 613 } 614 } 615 616 int 617 sshkey_ec_nid_to_hash_alg(int nid) 618 { 619 int kbits = sshkey_curve_nid_to_bits(nid); 620 621 if (kbits <= 0) 622 return -1; 623 624 /* RFC5656 section 6.2.1 */ 625 if (kbits <= 256) 626 return SSH_DIGEST_SHA256; 627 else if (kbits <= 384) 628 return SSH_DIGEST_SHA384; 629 else 630 return SSH_DIGEST_SHA512; 631 } 632 #endif /* WITH_OPENSSL */ 633 634 static void 635 cert_free(struct sshkey_cert *cert) 636 { 637 u_int i; 638 639 if (cert == NULL) 640 return; 641 sshbuf_free(cert->certblob); 642 sshbuf_free(cert->critical); 643 sshbuf_free(cert->extensions); 644 free(cert->key_id); 645 for (i = 0; i < cert->nprincipals; i++) 646 free(cert->principals[i]); 647 free(cert->principals); 648 sshkey_free(cert->signature_key); 649 free(cert->signature_type); 650 freezero(cert, sizeof(*cert)); 651 } 652 653 static struct sshkey_cert * 654 cert_new(void) 655 { 656 struct sshkey_cert *cert; 657 658 if ((cert = calloc(1, sizeof(*cert))) == NULL) 659 return NULL; 660 if ((cert->certblob = sshbuf_new()) == NULL || 661 (cert->critical = sshbuf_new()) == NULL || 662 (cert->extensions = sshbuf_new()) == NULL) { 663 cert_free(cert); 664 return NULL; 665 } 666 cert->key_id = NULL; 667 cert->principals = NULL; 668 cert->signature_key = NULL; 669 cert->signature_type = NULL; 670 return cert; 671 } 672 673 struct sshkey * 674 sshkey_new(int type) 675 { 676 struct sshkey *k; 677 const struct sshkey_impl *impl = NULL; 678 679 if (type != KEY_UNSPEC && 680 (impl = sshkey_impl_from_type(type)) == NULL) 681 return NULL; 682 683 /* All non-certificate types may act as CAs */ 684 if ((k = calloc(1, sizeof(*k))) == NULL) 685 return NULL; 686 k->type = type; 687 k->ecdsa_nid = -1; 688 if (impl != NULL && impl->funcs->alloc != NULL) { 689 if (impl->funcs->alloc(k) != 0) { 690 free(k); 691 return NULL; 692 } 693 } 694 if (sshkey_is_cert(k)) { 695 if ((k->cert = cert_new()) == NULL) { 696 sshkey_free(k); 697 return NULL; 698 } 699 } 700 701 return k; 702 } 703 704 /* Frees common FIDO fields */ 705 void 706 sshkey_sk_cleanup(struct sshkey *k) 707 { 708 free(k->sk_application); 709 sshbuf_free(k->sk_key_handle); 710 sshbuf_free(k->sk_reserved); 711 k->sk_application = NULL; 712 k->sk_key_handle = k->sk_reserved = NULL; 713 } 714 715 #if defined(MAP_CONCEAL) 716 # define PREKEY_MMAP_FLAG MAP_CONCEAL 717 #elif defined(MAP_NOCORE) 718 # define PREKEY_MMAP_FLAG MAP_NOCORE 719 #else 720 # define PREKEY_MMAP_FLAG 0 721 #endif 722 723 static int 724 sshkey_prekey_alloc(u_char **prekeyp, size_t len) 725 { 726 #if defined(HAVE_MMAP) && defined(MAP_ANON) && defined(MAP_PRIVATE) 727 u_char *prekey; 728 729 *prekeyp = NULL; 730 if ((prekey = mmap(NULL, len, PROT_READ|PROT_WRITE, 731 MAP_ANON|MAP_PRIVATE|PREKEY_MMAP_FLAG, -1, 0)) == MAP_FAILED) 732 return SSH_ERR_SYSTEM_ERROR; 733 #if defined(MADV_DONTDUMP) && !defined(MAP_CONCEAL) && !defined(MAP_NOCORE) 734 (void)madvise(prekey, len, MADV_DONTDUMP); 735 #endif 736 *prekeyp = prekey; 737 #else 738 *prekeyp = calloc(1, len); 739 #endif /* HAVE_MMAP et al */ 740 return 0; 741 } 742 743 static void 744 sshkey_prekey_free(void *prekey, size_t len) 745 { 746 #if defined(HAVE_MMAP) && defined(MAP_ANON) && defined(MAP_PRIVATE) 747 if (prekey == NULL) 748 return; 749 munmap(prekey, len); 750 #else 751 free(prekey); 752 #endif /* HAVE_MMAP et al */ 753 } 754 755 static void 756 sshkey_free_contents(struct sshkey *k) 757 { 758 const struct sshkey_impl *impl; 759 760 if (k == NULL) 761 return; 762 if ((k->flags & SSHKEY_FLAG_EXT) != 0) 763 pkcs11_key_free(k); 764 if ((impl = sshkey_impl_from_type(k->type)) != NULL && 765 impl->funcs->cleanup != NULL) 766 impl->funcs->cleanup(k); 767 if (sshkey_is_cert(k)) 768 cert_free(k->cert); 769 freezero(k->shielded_private, k->shielded_len); 770 sshkey_prekey_free(k->shield_prekey, k->shield_prekey_len); 771 } 772 773 void 774 sshkey_free(struct sshkey *k) 775 { 776 sshkey_free_contents(k); 777 freezero(k, sizeof(*k)); 778 } 779 780 static int 781 cert_compare(struct sshkey_cert *a, struct sshkey_cert *b) 782 { 783 if (a == NULL && b == NULL) 784 return 1; 785 if (a == NULL || b == NULL) 786 return 0; 787 if (sshbuf_len(a->certblob) != sshbuf_len(b->certblob)) 788 return 0; 789 if (timingsafe_bcmp(sshbuf_ptr(a->certblob), sshbuf_ptr(b->certblob), 790 sshbuf_len(a->certblob)) != 0) 791 return 0; 792 return 1; 793 } 794 795 /* Compares FIDO-specific pubkey fields only */ 796 int 797 sshkey_sk_fields_equal(const struct sshkey *a, const struct sshkey *b) 798 { 799 if (a->sk_application == NULL || b->sk_application == NULL) 800 return 0; 801 if (strcmp(a->sk_application, b->sk_application) != 0) 802 return 0; 803 return 1; 804 } 805 806 /* 807 * Compare public portions of key only, allowing comparisons between 808 * certificates and plain keys too. 809 */ 810 int 811 sshkey_equal_public(const struct sshkey *a, const struct sshkey *b) 812 { 813 const struct sshkey_impl *impl; 814 815 if (a == NULL || b == NULL || 816 sshkey_type_plain(a->type) != sshkey_type_plain(b->type)) 817 return 0; 818 if ((impl = sshkey_impl_from_type(a->type)) == NULL) 819 return 0; 820 return impl->funcs->equal(a, b); 821 } 822 823 int 824 sshkey_equal(const struct sshkey *a, const struct sshkey *b) 825 { 826 if (a == NULL || b == NULL || a->type != b->type) 827 return 0; 828 if (sshkey_is_cert(a)) { 829 if (!cert_compare(a->cert, b->cert)) 830 return 0; 831 } 832 return sshkey_equal_public(a, b); 833 } 834 835 836 /* Serialise common FIDO key parts */ 837 int 838 sshkey_serialize_sk(const struct sshkey *key, struct sshbuf *b) 839 { 840 int r; 841 842 if ((r = sshbuf_put_cstring(b, key->sk_application)) != 0) 843 return r; 844 845 return 0; 846 } 847 848 static int 849 to_blob_buf(const struct sshkey *key, struct sshbuf *b, int force_plain, 850 enum sshkey_serialize_rep opts) 851 { 852 int type, ret = SSH_ERR_INTERNAL_ERROR; 853 const char *typename; 854 const struct sshkey_impl *impl; 855 856 if (key == NULL) 857 return SSH_ERR_INVALID_ARGUMENT; 858 859 type = force_plain ? sshkey_type_plain(key->type) : key->type; 860 861 if (sshkey_type_is_cert(type)) { 862 if (key->cert == NULL) 863 return SSH_ERR_EXPECTED_CERT; 864 if (sshbuf_len(key->cert->certblob) == 0) 865 return SSH_ERR_KEY_LACKS_CERTBLOB; 866 /* Use the existing blob */ 867 if ((ret = sshbuf_putb(b, key->cert->certblob)) != 0) 868 return ret; 869 return 0; 870 } 871 if ((impl = sshkey_impl_from_type(type)) == NULL) 872 return SSH_ERR_KEY_TYPE_UNKNOWN; 873 874 typename = sshkey_ssh_name_from_type_nid(type, key->ecdsa_nid); 875 if ((ret = sshbuf_put_cstring(b, typename)) != 0) 876 return ret; 877 return impl->funcs->serialize_public(key, b, opts); 878 } 879 880 int 881 sshkey_putb(const struct sshkey *key, struct sshbuf *b) 882 { 883 return to_blob_buf(key, b, 0, SSHKEY_SERIALIZE_DEFAULT); 884 } 885 886 static int 887 sshkey_puts_opts_internal(const struct sshkey *key, struct sshbuf *b, 888 enum sshkey_serialize_rep opts, int force_plain) 889 { 890 struct sshbuf *tmp; 891 int r; 892 893 if ((tmp = sshbuf_new()) == NULL) 894 return SSH_ERR_ALLOC_FAIL; 895 r = to_blob_buf(key, tmp, force_plain, opts); 896 if (r == 0) 897 r = sshbuf_put_stringb(b, tmp); 898 sshbuf_free(tmp); 899 return r; 900 } 901 902 int 903 sshkey_puts(const struct sshkey *key, struct sshbuf *b) 904 { 905 return sshkey_puts_opts_internal(key, b, SSHKEY_SERIALIZE_DEFAULT, 0); 906 } 907 908 int 909 sshkey_putb_plain(const struct sshkey *key, struct sshbuf *b) 910 { 911 return to_blob_buf(key, b, 1, SSHKEY_SERIALIZE_DEFAULT); 912 } 913 914 int 915 sshkey_puts_plain(const struct sshkey *key, struct sshbuf *b) 916 { 917 return sshkey_puts_opts_internal(key, b, SSHKEY_SERIALIZE_DEFAULT, 1); 918 } 919 920 static int 921 to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp, int force_plain, 922 enum sshkey_serialize_rep opts) 923 { 924 int ret = SSH_ERR_INTERNAL_ERROR; 925 size_t len; 926 struct sshbuf *b = NULL; 927 928 if (lenp != NULL) 929 *lenp = 0; 930 if (blobp != NULL) 931 *blobp = NULL; 932 if ((b = sshbuf_new()) == NULL) 933 return SSH_ERR_ALLOC_FAIL; 934 if ((ret = to_blob_buf(key, b, force_plain, opts)) != 0) 935 goto out; 936 len = sshbuf_len(b); 937 if (lenp != NULL) 938 *lenp = len; 939 if (blobp != NULL) { 940 if ((*blobp = malloc(len)) == NULL) { 941 ret = SSH_ERR_ALLOC_FAIL; 942 goto out; 943 } 944 memcpy(*blobp, sshbuf_ptr(b), len); 945 } 946 ret = 0; 947 out: 948 sshbuf_free(b); 949 return ret; 950 } 951 952 int 953 sshkey_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp) 954 { 955 return to_blob(key, blobp, lenp, 0, SSHKEY_SERIALIZE_DEFAULT); 956 } 957 958 int 959 sshkey_plain_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp) 960 { 961 return to_blob(key, blobp, lenp, 1, SSHKEY_SERIALIZE_DEFAULT); 962 } 963 964 int 965 sshkey_fingerprint_raw(const struct sshkey *k, int dgst_alg, 966 u_char **retp, size_t *lenp) 967 { 968 u_char *blob = NULL, *ret = NULL; 969 size_t blob_len = 0; 970 int r = SSH_ERR_INTERNAL_ERROR; 971 972 if (retp != NULL) 973 *retp = NULL; 974 if (lenp != NULL) 975 *lenp = 0; 976 if (ssh_digest_bytes(dgst_alg) == 0) { 977 r = SSH_ERR_INVALID_ARGUMENT; 978 goto out; 979 } 980 if ((r = to_blob(k, &blob, &blob_len, 1, SSHKEY_SERIALIZE_DEFAULT)) 981 != 0) 982 goto out; 983 if ((ret = calloc(1, SSH_DIGEST_MAX_LENGTH)) == NULL) { 984 r = SSH_ERR_ALLOC_FAIL; 985 goto out; 986 } 987 if ((r = ssh_digest_memory(dgst_alg, blob, blob_len, 988 ret, SSH_DIGEST_MAX_LENGTH)) != 0) 989 goto out; 990 /* success */ 991 if (retp != NULL) { 992 *retp = ret; 993 ret = NULL; 994 } 995 if (lenp != NULL) 996 *lenp = ssh_digest_bytes(dgst_alg); 997 r = 0; 998 out: 999 free(ret); 1000 if (blob != NULL) 1001 freezero(blob, blob_len); 1002 return r; 1003 } 1004 1005 static char * 1006 fingerprint_b64(const char *alg, u_char *dgst_raw, size_t dgst_raw_len) 1007 { 1008 char *ret; 1009 size_t plen = strlen(alg) + 1; 1010 size_t rlen = ((dgst_raw_len + 2) / 3) * 4 + plen + 1; 1011 1012 if (dgst_raw_len > 65536 || (ret = calloc(1, rlen)) == NULL) 1013 return NULL; 1014 strlcpy(ret, alg, rlen); 1015 strlcat(ret, ":", rlen); 1016 if (dgst_raw_len == 0) 1017 return ret; 1018 if (b64_ntop(dgst_raw, dgst_raw_len, ret + plen, rlen - plen) == -1) { 1019 freezero(ret, rlen); 1020 return NULL; 1021 } 1022 /* Trim padding characters from end */ 1023 ret[strcspn(ret, "=")] = '\0'; 1024 return ret; 1025 } 1026 1027 static char * 1028 fingerprint_hex(const char *alg, u_char *dgst_raw, size_t dgst_raw_len) 1029 { 1030 char *retval, hex[5]; 1031 size_t i, rlen = dgst_raw_len * 3 + strlen(alg) + 2; 1032 1033 if (dgst_raw_len > 65536 || (retval = calloc(1, rlen)) == NULL) 1034 return NULL; 1035 strlcpy(retval, alg, rlen); 1036 strlcat(retval, ":", rlen); 1037 for (i = 0; i < dgst_raw_len; i++) { 1038 snprintf(hex, sizeof(hex), "%s%02x", 1039 i > 0 ? ":" : "", dgst_raw[i]); 1040 strlcat(retval, hex, rlen); 1041 } 1042 return retval; 1043 } 1044 1045 static char * 1046 fingerprint_bubblebabble(u_char *dgst_raw, size_t dgst_raw_len) 1047 { 1048 char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' }; 1049 char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm', 1050 'n', 'p', 'r', 's', 't', 'v', 'z', 'x' }; 1051 u_int i, j = 0, rounds, seed = 1; 1052 char *retval; 1053 1054 rounds = (dgst_raw_len / 2) + 1; 1055 if ((retval = calloc(rounds, 6)) == NULL) 1056 return NULL; 1057 retval[j++] = 'x'; 1058 for (i = 0; i < rounds; i++) { 1059 u_int idx0, idx1, idx2, idx3, idx4; 1060 if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) { 1061 idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) + 1062 seed) % 6; 1063 idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15; 1064 idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) + 1065 (seed / 6)) % 6; 1066 retval[j++] = vowels[idx0]; 1067 retval[j++] = consonants[idx1]; 1068 retval[j++] = vowels[idx2]; 1069 if ((i + 1) < rounds) { 1070 idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15; 1071 idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15; 1072 retval[j++] = consonants[idx3]; 1073 retval[j++] = '-'; 1074 retval[j++] = consonants[idx4]; 1075 seed = ((seed * 5) + 1076 ((((u_int)(dgst_raw[2 * i])) * 7) + 1077 ((u_int)(dgst_raw[(2 * i) + 1])))) % 36; 1078 } 1079 } else { 1080 idx0 = seed % 6; 1081 idx1 = 16; 1082 idx2 = seed / 6; 1083 retval[j++] = vowels[idx0]; 1084 retval[j++] = consonants[idx1]; 1085 retval[j++] = vowels[idx2]; 1086 } 1087 } 1088 retval[j++] = 'x'; 1089 retval[j++] = '\0'; 1090 return retval; 1091 } 1092 1093 /* 1094 * Draw an ASCII-Art representing the fingerprint so human brain can 1095 * profit from its built-in pattern recognition ability. 1096 * This technique is called "random art" and can be found in some 1097 * scientific publications like this original paper: 1098 * 1099 * "Hash Visualization: a New Technique to improve Real-World Security", 1100 * Perrig A. and Song D., 1999, International Workshop on Cryptographic 1101 * Techniques and E-Commerce (CrypTEC '99) 1102 * sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf 1103 * 1104 * The subject came up in a talk by Dan Kaminsky, too. 1105 * 1106 * If you see the picture is different, the key is different. 1107 * If the picture looks the same, you still know nothing. 1108 * 1109 * The algorithm used here is a worm crawling over a discrete plane, 1110 * leaving a trace (augmenting the field) everywhere it goes. 1111 * Movement is taken from dgst_raw 2bit-wise. Bumping into walls 1112 * makes the respective movement vector be ignored for this turn. 1113 * Graphs are not unambiguous, because circles in graphs can be 1114 * walked in either direction. 1115 */ 1116 1117 /* 1118 * Field sizes for the random art. Have to be odd, so the starting point 1119 * can be in the exact middle of the picture, and FLDBASE should be >=8 . 1120 * Else pictures would be too dense, and drawing the frame would 1121 * fail, too, because the key type would not fit in anymore. 1122 */ 1123 #define FLDBASE 8 1124 #define FLDSIZE_Y (FLDBASE + 1) 1125 #define FLDSIZE_X (FLDBASE * 2 + 1) 1126 static char * 1127 fingerprint_randomart(const char *alg, u_char *dgst_raw, size_t dgst_raw_len, 1128 const struct sshkey *k) 1129 { 1130 /* 1131 * Chars to be used after each other every time the worm 1132 * intersects with itself. Matter of taste. 1133 */ 1134 char *augmentation_string = " .o+=*BOX@%&#/^SE"; 1135 char *retval, *p, title[FLDSIZE_X], hash[FLDSIZE_X]; 1136 u_char field[FLDSIZE_X][FLDSIZE_Y]; 1137 size_t i, tlen, hlen; 1138 u_int b; 1139 int x, y, r; 1140 size_t len = strlen(augmentation_string) - 1; 1141 1142 if ((retval = calloc((FLDSIZE_X + 3), (FLDSIZE_Y + 2))) == NULL) 1143 return NULL; 1144 1145 /* initialize field */ 1146 memset(field, 0, FLDSIZE_X * FLDSIZE_Y * sizeof(char)); 1147 x = FLDSIZE_X / 2; 1148 y = FLDSIZE_Y / 2; 1149 1150 /* process raw key */ 1151 for (i = 0; i < dgst_raw_len; i++) { 1152 int input; 1153 /* each byte conveys four 2-bit move commands */ 1154 input = dgst_raw[i]; 1155 for (b = 0; b < 4; b++) { 1156 /* evaluate 2 bit, rest is shifted later */ 1157 x += (input & 0x1) ? 1 : -1; 1158 y += (input & 0x2) ? 1 : -1; 1159 1160 /* assure we are still in bounds */ 1161 x = MAXIMUM(x, 0); 1162 y = MAXIMUM(y, 0); 1163 x = MINIMUM(x, FLDSIZE_X - 1); 1164 y = MINIMUM(y, FLDSIZE_Y - 1); 1165 1166 /* augment the field */ 1167 if (field[x][y] < len - 2) 1168 field[x][y]++; 1169 input = input >> 2; 1170 } 1171 } 1172 1173 /* mark starting point and end point*/ 1174 field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = len - 1; 1175 field[x][y] = len; 1176 1177 /* assemble title */ 1178 r = snprintf(title, sizeof(title), "[%s %u]", 1179 sshkey_type(k), sshkey_size(k)); 1180 /* If [type size] won't fit, then try [type]; fits "[ED25519-CERT]" */ 1181 if (r < 0 || r > (int)sizeof(title)) 1182 r = snprintf(title, sizeof(title), "[%s]", sshkey_type(k)); 1183 tlen = (r <= 0) ? 0 : strlen(title); 1184 1185 /* assemble hash ID. */ 1186 r = snprintf(hash, sizeof(hash), "[%s]", alg); 1187 hlen = (r <= 0) ? 0 : strlen(hash); 1188 1189 /* output upper border */ 1190 p = retval; 1191 *p++ = '+'; 1192 for (i = 0; i < (FLDSIZE_X - tlen) / 2; i++) 1193 *p++ = '-'; 1194 memcpy(p, title, tlen); 1195 p += tlen; 1196 for (i += tlen; i < FLDSIZE_X; i++) 1197 *p++ = '-'; 1198 *p++ = '+'; 1199 *p++ = '\n'; 1200 1201 /* output content */ 1202 for (y = 0; y < FLDSIZE_Y; y++) { 1203 *p++ = '|'; 1204 for (x = 0; x < FLDSIZE_X; x++) 1205 *p++ = augmentation_string[MINIMUM(field[x][y], len)]; 1206 *p++ = '|'; 1207 *p++ = '\n'; 1208 } 1209 1210 /* output lower border */ 1211 *p++ = '+'; 1212 for (i = 0; i < (FLDSIZE_X - hlen) / 2; i++) 1213 *p++ = '-'; 1214 memcpy(p, hash, hlen); 1215 p += hlen; 1216 for (i += hlen; i < FLDSIZE_X; i++) 1217 *p++ = '-'; 1218 *p++ = '+'; 1219 1220 return retval; 1221 } 1222 1223 char * 1224 sshkey_fingerprint(const struct sshkey *k, int dgst_alg, 1225 enum sshkey_fp_rep dgst_rep) 1226 { 1227 char *retval = NULL; 1228 u_char *dgst_raw; 1229 size_t dgst_raw_len; 1230 1231 if (sshkey_fingerprint_raw(k, dgst_alg, &dgst_raw, &dgst_raw_len) != 0) 1232 return NULL; 1233 switch (dgst_rep) { 1234 case SSH_FP_DEFAULT: 1235 if (dgst_alg == SSH_DIGEST_MD5) { 1236 retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg), 1237 dgst_raw, dgst_raw_len); 1238 } else { 1239 retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg), 1240 dgst_raw, dgst_raw_len); 1241 } 1242 break; 1243 case SSH_FP_HEX: 1244 retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg), 1245 dgst_raw, dgst_raw_len); 1246 break; 1247 case SSH_FP_BASE64: 1248 retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg), 1249 dgst_raw, dgst_raw_len); 1250 break; 1251 case SSH_FP_BUBBLEBABBLE: 1252 retval = fingerprint_bubblebabble(dgst_raw, dgst_raw_len); 1253 break; 1254 case SSH_FP_RANDOMART: 1255 retval = fingerprint_randomart(ssh_digest_alg_name(dgst_alg), 1256 dgst_raw, dgst_raw_len, k); 1257 break; 1258 default: 1259 freezero(dgst_raw, dgst_raw_len); 1260 return NULL; 1261 } 1262 freezero(dgst_raw, dgst_raw_len); 1263 return retval; 1264 } 1265 1266 static int 1267 peek_type_nid(const char *s, size_t l, int *nid) 1268 { 1269 const struct sshkey_impl *impl; 1270 int i; 1271 1272 for (i = 0; keyimpls[i] != NULL; i++) { 1273 impl = keyimpls[i]; 1274 if (impl->name == NULL || strlen(impl->name) != l) 1275 continue; 1276 if (memcmp(s, impl->name, l) == 0) { 1277 *nid = -1; 1278 if (key_type_is_ecdsa_variant(impl->type)) 1279 *nid = impl->nid; 1280 return impl->type; 1281 } 1282 } 1283 return KEY_UNSPEC; 1284 } 1285 1286 /* XXX this can now be made const char * */ 1287 int 1288 sshkey_read(struct sshkey *ret, char **cpp) 1289 { 1290 struct sshkey *k; 1291 char *cp, *blobcopy; 1292 size_t space; 1293 int r, type, curve_nid = -1; 1294 struct sshbuf *blob; 1295 1296 if (ret == NULL) 1297 return SSH_ERR_INVALID_ARGUMENT; 1298 if (ret->type != KEY_UNSPEC && sshkey_impl_from_type(ret->type) == NULL) 1299 return SSH_ERR_INVALID_ARGUMENT; 1300 1301 /* Decode type */ 1302 cp = *cpp; 1303 space = strcspn(cp, " \t"); 1304 if (space == strlen(cp)) 1305 return SSH_ERR_INVALID_FORMAT; 1306 if ((type = peek_type_nid(cp, space, &curve_nid)) == KEY_UNSPEC) 1307 return SSH_ERR_INVALID_FORMAT; 1308 1309 /* skip whitespace */ 1310 for (cp += space; *cp == ' ' || *cp == '\t'; cp++) 1311 ; 1312 if (*cp == '\0') 1313 return SSH_ERR_INVALID_FORMAT; 1314 if (ret->type != KEY_UNSPEC && ret->type != type) 1315 return SSH_ERR_KEY_TYPE_MISMATCH; 1316 if ((blob = sshbuf_new()) == NULL) 1317 return SSH_ERR_ALLOC_FAIL; 1318 1319 /* find end of keyblob and decode */ 1320 space = strcspn(cp, " \t"); 1321 if ((blobcopy = strndup(cp, space)) == NULL) { 1322 sshbuf_free(blob); 1323 return SSH_ERR_ALLOC_FAIL; 1324 } 1325 if ((r = sshbuf_b64tod(blob, blobcopy)) != 0) { 1326 free(blobcopy); 1327 sshbuf_free(blob); 1328 return r; 1329 } 1330 free(blobcopy); 1331 if ((r = sshkey_fromb(blob, &k)) != 0) { 1332 sshbuf_free(blob); 1333 return r; 1334 } 1335 sshbuf_free(blob); 1336 1337 /* skip whitespace and leave cp at start of comment */ 1338 for (cp += space; *cp == ' ' || *cp == '\t'; cp++) 1339 ; 1340 1341 /* ensure type of blob matches type at start of line */ 1342 if (k->type != type) { 1343 sshkey_free(k); 1344 return SSH_ERR_KEY_TYPE_MISMATCH; 1345 } 1346 if (key_type_is_ecdsa_variant(type) && curve_nid != k->ecdsa_nid) { 1347 sshkey_free(k); 1348 return SSH_ERR_EC_CURVE_MISMATCH; 1349 } 1350 1351 /* Fill in ret from parsed key */ 1352 sshkey_free_contents(ret); 1353 *ret = *k; 1354 freezero(k, sizeof(*k)); 1355 1356 /* success */ 1357 *cpp = cp; 1358 return 0; 1359 } 1360 1361 int 1362 sshkey_to_base64(const struct sshkey *key, char **b64p) 1363 { 1364 int r = SSH_ERR_INTERNAL_ERROR; 1365 struct sshbuf *b = NULL; 1366 char *uu = NULL; 1367 1368 if (b64p != NULL) 1369 *b64p = NULL; 1370 if ((b = sshbuf_new()) == NULL) 1371 return SSH_ERR_ALLOC_FAIL; 1372 if ((r = sshkey_putb(key, b)) != 0) 1373 goto out; 1374 if ((uu = sshbuf_dtob64_string(b, 0)) == NULL) { 1375 r = SSH_ERR_ALLOC_FAIL; 1376 goto out; 1377 } 1378 /* Success */ 1379 if (b64p != NULL) { 1380 *b64p = uu; 1381 uu = NULL; 1382 } 1383 r = 0; 1384 out: 1385 sshbuf_free(b); 1386 free(uu); 1387 return r; 1388 } 1389 1390 int 1391 sshkey_format_text(const struct sshkey *key, struct sshbuf *b) 1392 { 1393 int r = SSH_ERR_INTERNAL_ERROR; 1394 char *uu = NULL; 1395 1396 if ((r = sshkey_to_base64(key, &uu)) != 0) 1397 goto out; 1398 if ((r = sshbuf_putf(b, "%s %s", 1399 sshkey_ssh_name(key), uu)) != 0) 1400 goto out; 1401 r = 0; 1402 out: 1403 free(uu); 1404 return r; 1405 } 1406 1407 int 1408 sshkey_write(const struct sshkey *key, FILE *f) 1409 { 1410 struct sshbuf *b = NULL; 1411 int r = SSH_ERR_INTERNAL_ERROR; 1412 1413 if ((b = sshbuf_new()) == NULL) 1414 return SSH_ERR_ALLOC_FAIL; 1415 if ((r = sshkey_format_text(key, b)) != 0) 1416 goto out; 1417 if (fwrite(sshbuf_ptr(b), sshbuf_len(b), 1, f) != 1) { 1418 if (feof(f)) 1419 errno = EPIPE; 1420 r = SSH_ERR_SYSTEM_ERROR; 1421 goto out; 1422 } 1423 /* Success */ 1424 r = 0; 1425 out: 1426 sshbuf_free(b); 1427 return r; 1428 } 1429 1430 const char * 1431 sshkey_cert_type(const struct sshkey *k) 1432 { 1433 switch (k->cert->type) { 1434 case SSH2_CERT_TYPE_USER: 1435 return "user"; 1436 case SSH2_CERT_TYPE_HOST: 1437 return "host"; 1438 default: 1439 return "unknown"; 1440 } 1441 } 1442 1443 int 1444 sshkey_check_rsa_length(const struct sshkey *k, int min_size) 1445 { 1446 #ifdef WITH_OPENSSL 1447 int nbits; 1448 1449 if (k == NULL || k->pkey == NULL || 1450 (k->type != KEY_RSA && k->type != KEY_RSA_CERT)) 1451 return 0; 1452 nbits = EVP_PKEY_bits(k->pkey); 1453 if (nbits < SSH_RSA_MINIMUM_MODULUS_SIZE || 1454 (min_size > 0 && nbits < min_size)) 1455 return SSH_ERR_KEY_LENGTH; 1456 #endif /* WITH_OPENSSL */ 1457 return 0; 1458 } 1459 1460 #if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) 1461 int 1462 sshkey_ecdsa_key_to_nid(const EC_KEY *k) 1463 { 1464 const EC_GROUP *g; 1465 int nid; 1466 1467 if (k == NULL || (g = EC_KEY_get0_group(k)) == NULL) 1468 return -1; 1469 if ((nid = EC_GROUP_get_curve_name(g)) <= 0) 1470 return -1; 1471 return nid; 1472 } 1473 1474 int 1475 sshkey_ecdsa_pkey_to_nid(EVP_PKEY *pkey) 1476 { 1477 return sshkey_ecdsa_key_to_nid(EVP_PKEY_get0_EC_KEY(pkey)); 1478 } 1479 #endif /* defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) */ 1480 1481 int 1482 sshkey_generate(int type, u_int bits, struct sshkey **keyp) 1483 { 1484 struct sshkey *k; 1485 int ret = SSH_ERR_INTERNAL_ERROR; 1486 const struct sshkey_impl *impl; 1487 1488 if (keyp == NULL || sshkey_type_is_cert(type)) 1489 return SSH_ERR_INVALID_ARGUMENT; 1490 *keyp = NULL; 1491 if ((impl = sshkey_impl_from_type(type)) == NULL) 1492 return SSH_ERR_KEY_TYPE_UNKNOWN; 1493 if (impl->funcs->generate == NULL) 1494 return SSH_ERR_FEATURE_UNSUPPORTED; 1495 if ((k = sshkey_new(KEY_UNSPEC)) == NULL) 1496 return SSH_ERR_ALLOC_FAIL; 1497 k->type = type; 1498 if ((ret = impl->funcs->generate(k, bits)) != 0) { 1499 sshkey_free(k); 1500 return ret; 1501 } 1502 /* success */ 1503 *keyp = k; 1504 return 0; 1505 } 1506 1507 int 1508 sshkey_cert_copy(const struct sshkey *from_key, struct sshkey *to_key) 1509 { 1510 u_int i; 1511 const struct sshkey_cert *from; 1512 struct sshkey_cert *to; 1513 int r = SSH_ERR_INTERNAL_ERROR; 1514 1515 if (to_key == NULL || (from = from_key->cert) == NULL) 1516 return SSH_ERR_INVALID_ARGUMENT; 1517 1518 if ((to = cert_new()) == NULL) 1519 return SSH_ERR_ALLOC_FAIL; 1520 1521 if ((r = sshbuf_putb(to->certblob, from->certblob)) != 0 || 1522 (r = sshbuf_putb(to->critical, from->critical)) != 0 || 1523 (r = sshbuf_putb(to->extensions, from->extensions)) != 0) 1524 goto out; 1525 1526 to->serial = from->serial; 1527 to->type = from->type; 1528 if (from->key_id == NULL) 1529 to->key_id = NULL; 1530 else if ((to->key_id = strdup(from->key_id)) == NULL) { 1531 r = SSH_ERR_ALLOC_FAIL; 1532 goto out; 1533 } 1534 to->valid_after = from->valid_after; 1535 to->valid_before = from->valid_before; 1536 if (from->signature_key == NULL) 1537 to->signature_key = NULL; 1538 else if ((r = sshkey_from_private(from->signature_key, 1539 &to->signature_key)) != 0) 1540 goto out; 1541 if (from->signature_type != NULL && 1542 (to->signature_type = strdup(from->signature_type)) == NULL) { 1543 r = SSH_ERR_ALLOC_FAIL; 1544 goto out; 1545 } 1546 if (from->nprincipals > SSHKEY_CERT_MAX_PRINCIPALS) { 1547 r = SSH_ERR_INVALID_ARGUMENT; 1548 goto out; 1549 } 1550 if (from->nprincipals > 0) { 1551 if ((to->principals = calloc(from->nprincipals, 1552 sizeof(*to->principals))) == NULL) { 1553 r = SSH_ERR_ALLOC_FAIL; 1554 goto out; 1555 } 1556 for (i = 0; i < from->nprincipals; i++) { 1557 to->principals[i] = strdup(from->principals[i]); 1558 if (to->principals[i] == NULL) { 1559 to->nprincipals = i; 1560 r = SSH_ERR_ALLOC_FAIL; 1561 goto out; 1562 } 1563 } 1564 } 1565 to->nprincipals = from->nprincipals; 1566 1567 /* success */ 1568 cert_free(to_key->cert); 1569 to_key->cert = to; 1570 to = NULL; 1571 r = 0; 1572 out: 1573 cert_free(to); 1574 return r; 1575 } 1576 1577 int 1578 sshkey_copy_public_sk(const struct sshkey *from, struct sshkey *to) 1579 { 1580 /* Append security-key application string */ 1581 if ((to->sk_application = strdup(from->sk_application)) == NULL) 1582 return SSH_ERR_ALLOC_FAIL; 1583 return 0; 1584 } 1585 1586 int 1587 sshkey_from_private(const struct sshkey *k, struct sshkey **pkp) 1588 { 1589 struct sshkey *n = NULL; 1590 int r = SSH_ERR_INTERNAL_ERROR; 1591 const struct sshkey_impl *impl; 1592 1593 *pkp = NULL; 1594 if ((impl = sshkey_impl_from_key(k)) == NULL) 1595 return SSH_ERR_KEY_TYPE_UNKNOWN; 1596 if ((n = sshkey_new(k->type)) == NULL) { 1597 r = SSH_ERR_ALLOC_FAIL; 1598 goto out; 1599 } 1600 if ((r = impl->funcs->copy_public(k, n)) != 0) 1601 goto out; 1602 if (sshkey_is_cert(k) && (r = sshkey_cert_copy(k, n)) != 0) 1603 goto out; 1604 /* success */ 1605 *pkp = n; 1606 n = NULL; 1607 r = 0; 1608 out: 1609 sshkey_free(n); 1610 return r; 1611 } 1612 1613 int 1614 sshkey_is_shielded(struct sshkey *k) 1615 { 1616 return k != NULL && k->shielded_private != NULL; 1617 } 1618 1619 int 1620 sshkey_shield_private(struct sshkey *k) 1621 { 1622 struct sshbuf *prvbuf = NULL; 1623 u_char *prekey = NULL, *enc = NULL, keyiv[SSH_DIGEST_MAX_LENGTH]; 1624 struct sshcipher_ctx *cctx = NULL; 1625 const struct sshcipher *cipher; 1626 size_t i, enclen = 0; 1627 struct sshkey *kswap = NULL, tmp; 1628 int r = SSH_ERR_INTERNAL_ERROR; 1629 1630 #ifdef DEBUG_PK 1631 fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k)); 1632 #endif 1633 if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) { 1634 r = SSH_ERR_INVALID_ARGUMENT; 1635 goto out; 1636 } 1637 if (cipher_keylen(cipher) + cipher_ivlen(cipher) > 1638 ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) { 1639 r = SSH_ERR_INTERNAL_ERROR; 1640 goto out; 1641 } 1642 1643 /* Prepare a random pre-key, and from it an ephemeral key */ 1644 if ((r = sshkey_prekey_alloc(&prekey, SSHKEY_SHIELD_PREKEY_LEN)) != 0) 1645 goto out; 1646 arc4random_buf(prekey, SSHKEY_SHIELD_PREKEY_LEN); 1647 if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH, 1648 prekey, SSHKEY_SHIELD_PREKEY_LEN, 1649 keyiv, SSH_DIGEST_MAX_LENGTH)) != 0) 1650 goto out; 1651 #ifdef DEBUG_PK 1652 fprintf(stderr, "%s: key+iv\n", __func__); 1653 sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH), 1654 stderr); 1655 #endif 1656 if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher), 1657 keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 1)) != 0) 1658 goto out; 1659 1660 /* Serialise and encrypt the private key using the ephemeral key */ 1661 if ((prvbuf = sshbuf_new()) == NULL) { 1662 r = SSH_ERR_ALLOC_FAIL; 1663 goto out; 1664 } 1665 if (sshkey_is_shielded(k) && (r = sshkey_unshield_private(k)) != 0) 1666 goto out; 1667 if ((r = sshkey_private_serialize(k, prvbuf)) != 0) 1668 goto out; 1669 /* pad to cipher blocksize */ 1670 i = 0; 1671 while (sshbuf_len(prvbuf) % cipher_blocksize(cipher)) { 1672 if ((r = sshbuf_put_u8(prvbuf, ++i & 0xff)) != 0) 1673 goto out; 1674 } 1675 #ifdef DEBUG_PK 1676 fprintf(stderr, "%s: serialised\n", __func__); 1677 sshbuf_dump(prvbuf, stderr); 1678 #endif 1679 /* encrypt */ 1680 enclen = sshbuf_len(prvbuf); 1681 if ((enc = malloc(enclen)) == NULL) { 1682 r = SSH_ERR_ALLOC_FAIL; 1683 goto out; 1684 } 1685 if ((r = cipher_crypt(cctx, 0, enc, 1686 sshbuf_ptr(prvbuf), sshbuf_len(prvbuf), 0, 0)) != 0) 1687 goto out; 1688 #ifdef DEBUG_PK 1689 fprintf(stderr, "%s: encrypted\n", __func__); 1690 sshbuf_dump_data(enc, enclen, stderr); 1691 #endif 1692 1693 /* Make a scrubbed, public-only copy of our private key argument */ 1694 if ((r = sshkey_from_private(k, &kswap)) != 0) 1695 goto out; 1696 1697 /* Swap the private key out (it will be destroyed below) */ 1698 tmp = *kswap; 1699 *kswap = *k; 1700 *k = tmp; 1701 1702 /* Insert the shielded key into our argument */ 1703 k->shielded_private = enc; 1704 k->shielded_len = enclen; 1705 k->shield_prekey = prekey; 1706 k->shield_prekey_len = SSHKEY_SHIELD_PREKEY_LEN; 1707 enc = prekey = NULL; /* transferred */ 1708 enclen = 0; 1709 1710 /* preserve key fields that are required for correct operation */ 1711 k->sk_flags = kswap->sk_flags; 1712 1713 /* success */ 1714 r = 0; 1715 1716 out: 1717 /* XXX behaviour on error - invalidate original private key? */ 1718 cipher_free(cctx); 1719 explicit_bzero(keyiv, sizeof(keyiv)); 1720 explicit_bzero(&tmp, sizeof(tmp)); 1721 freezero(enc, enclen); 1722 sshkey_prekey_free(prekey, SSHKEY_SHIELD_PREKEY_LEN); 1723 sshkey_free(kswap); 1724 sshbuf_free(prvbuf); 1725 return r; 1726 } 1727 1728 /* Check deterministic padding after private key */ 1729 static int 1730 private2_check_padding(struct sshbuf *decrypted) 1731 { 1732 u_char pad; 1733 size_t i; 1734 int r; 1735 1736 i = 0; 1737 while (sshbuf_len(decrypted)) { 1738 if ((r = sshbuf_get_u8(decrypted, &pad)) != 0) 1739 goto out; 1740 if (pad != (++i & 0xff)) { 1741 r = SSH_ERR_INVALID_FORMAT; 1742 goto out; 1743 } 1744 } 1745 /* success */ 1746 r = 0; 1747 out: 1748 explicit_bzero(&pad, sizeof(pad)); 1749 explicit_bzero(&i, sizeof(i)); 1750 return r; 1751 } 1752 1753 int 1754 sshkey_unshield_private(struct sshkey *k) 1755 { 1756 struct sshbuf *prvbuf = NULL; 1757 u_char *cp, keyiv[SSH_DIGEST_MAX_LENGTH]; 1758 struct sshcipher_ctx *cctx = NULL; 1759 const struct sshcipher *cipher; 1760 struct sshkey *kswap = NULL, tmp; 1761 int r = SSH_ERR_INTERNAL_ERROR; 1762 1763 #ifdef DEBUG_PK 1764 fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k)); 1765 #endif 1766 if (!sshkey_is_shielded(k)) 1767 return 0; /* nothing to do */ 1768 1769 if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) { 1770 r = SSH_ERR_INVALID_ARGUMENT; 1771 goto out; 1772 } 1773 if (cipher_keylen(cipher) + cipher_ivlen(cipher) > 1774 ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) { 1775 r = SSH_ERR_INTERNAL_ERROR; 1776 goto out; 1777 } 1778 /* check size of shielded key blob */ 1779 if (k->shielded_len < cipher_blocksize(cipher) || 1780 (k->shielded_len % cipher_blocksize(cipher)) != 0) { 1781 r = SSH_ERR_INVALID_FORMAT; 1782 goto out; 1783 } 1784 1785 /* Calculate the ephemeral key from the prekey */ 1786 if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH, 1787 k->shield_prekey, k->shield_prekey_len, 1788 keyiv, SSH_DIGEST_MAX_LENGTH)) != 0) 1789 goto out; 1790 if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher), 1791 keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 0)) != 0) 1792 goto out; 1793 #ifdef DEBUG_PK 1794 fprintf(stderr, "%s: key+iv\n", __func__); 1795 sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH), 1796 stderr); 1797 #endif 1798 1799 /* Decrypt and parse the shielded private key using the ephemeral key */ 1800 if ((prvbuf = sshbuf_new()) == NULL) { 1801 r = SSH_ERR_ALLOC_FAIL; 1802 goto out; 1803 } 1804 if ((r = sshbuf_reserve(prvbuf, k->shielded_len, &cp)) != 0) 1805 goto out; 1806 /* decrypt */ 1807 #ifdef DEBUG_PK 1808 fprintf(stderr, "%s: encrypted\n", __func__); 1809 sshbuf_dump_data(k->shielded_private, k->shielded_len, stderr); 1810 #endif 1811 if ((r = cipher_crypt(cctx, 0, cp, 1812 k->shielded_private, k->shielded_len, 0, 0)) != 0) 1813 goto out; 1814 #ifdef DEBUG_PK 1815 fprintf(stderr, "%s: serialised\n", __func__); 1816 sshbuf_dump(prvbuf, stderr); 1817 #endif 1818 /* Parse private key */ 1819 if ((r = sshkey_private_deserialize(prvbuf, &kswap)) != 0) 1820 goto out; 1821 1822 if ((r = private2_check_padding(prvbuf)) != 0) 1823 goto out; 1824 1825 /* Swap the parsed key back into place */ 1826 tmp = *kswap; 1827 *kswap = *k; 1828 *k = tmp; 1829 1830 /* success */ 1831 r = 0; 1832 1833 out: 1834 cipher_free(cctx); 1835 explicit_bzero(keyiv, sizeof(keyiv)); 1836 explicit_bzero(&tmp, sizeof(tmp)); 1837 sshkey_free(kswap); 1838 sshbuf_free(prvbuf); 1839 return r; 1840 } 1841 1842 static int 1843 cert_parse(struct sshbuf *b, struct sshkey *key, struct sshbuf *certbuf) 1844 { 1845 struct sshbuf *principals = NULL, *crit = NULL; 1846 struct sshbuf *exts = NULL, *ca = NULL; 1847 u_char *sig = NULL; 1848 size_t signed_len = 0, slen = 0, kidlen = 0; 1849 int ret = SSH_ERR_INTERNAL_ERROR; 1850 1851 /* Copy the entire key blob for verification and later serialisation */ 1852 if ((ret = sshbuf_putb(key->cert->certblob, certbuf)) != 0) 1853 return ret; 1854 1855 /* Parse body of certificate up to signature */ 1856 if ((ret = sshbuf_get_u64(b, &key->cert->serial)) != 0 || 1857 (ret = sshbuf_get_u32(b, &key->cert->type)) != 0 || 1858 (ret = sshbuf_get_cstring(b, &key->cert->key_id, &kidlen)) != 0 || 1859 (ret = sshbuf_froms(b, &principals)) != 0 || 1860 (ret = sshbuf_get_u64(b, &key->cert->valid_after)) != 0 || 1861 (ret = sshbuf_get_u64(b, &key->cert->valid_before)) != 0 || 1862 (ret = sshbuf_froms(b, &crit)) != 0 || 1863 (ret = sshbuf_froms(b, &exts)) != 0 || 1864 (ret = sshbuf_get_string_direct(b, NULL, NULL)) != 0 || 1865 (ret = sshbuf_froms(b, &ca)) != 0) { 1866 /* XXX debug print error for ret */ 1867 ret = SSH_ERR_INVALID_FORMAT; 1868 goto out; 1869 } 1870 1871 /* Signature is left in the buffer so we can calculate this length */ 1872 signed_len = sshbuf_len(key->cert->certblob) - sshbuf_len(b); 1873 1874 if ((ret = sshbuf_get_string(b, &sig, &slen)) != 0) { 1875 ret = SSH_ERR_INVALID_FORMAT; 1876 goto out; 1877 } 1878 1879 if (key->cert->type != SSH2_CERT_TYPE_USER && 1880 key->cert->type != SSH2_CERT_TYPE_HOST) { 1881 ret = SSH_ERR_KEY_CERT_UNKNOWN_TYPE; 1882 goto out; 1883 } 1884 1885 /* Parse principals section */ 1886 while (sshbuf_len(principals) > 0) { 1887 char *principal = NULL; 1888 char **oprincipals = NULL; 1889 1890 if (key->cert->nprincipals >= SSHKEY_CERT_MAX_PRINCIPALS) { 1891 ret = SSH_ERR_INVALID_FORMAT; 1892 goto out; 1893 } 1894 if ((ret = sshbuf_get_cstring(principals, &principal, 1895 NULL)) != 0) { 1896 ret = SSH_ERR_INVALID_FORMAT; 1897 goto out; 1898 } 1899 oprincipals = key->cert->principals; 1900 key->cert->principals = recallocarray(key->cert->principals, 1901 key->cert->nprincipals, key->cert->nprincipals + 1, 1902 sizeof(*key->cert->principals)); 1903 if (key->cert->principals == NULL) { 1904 free(principal); 1905 key->cert->principals = oprincipals; 1906 ret = SSH_ERR_ALLOC_FAIL; 1907 goto out; 1908 } 1909 key->cert->principals[key->cert->nprincipals++] = principal; 1910 } 1911 1912 /* 1913 * Stash a copies of the critical options and extensions sections 1914 * for later use. 1915 */ 1916 if ((ret = sshbuf_putb(key->cert->critical, crit)) != 0 || 1917 (exts != NULL && 1918 (ret = sshbuf_putb(key->cert->extensions, exts)) != 0)) 1919 goto out; 1920 1921 /* 1922 * Validate critical options and extensions sections format. 1923 */ 1924 while (sshbuf_len(crit) != 0) { 1925 if ((ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0 || 1926 (ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0) { 1927 sshbuf_reset(key->cert->critical); 1928 ret = SSH_ERR_INVALID_FORMAT; 1929 goto out; 1930 } 1931 } 1932 while (exts != NULL && sshbuf_len(exts) != 0) { 1933 if ((ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0 || 1934 (ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0) { 1935 sshbuf_reset(key->cert->extensions); 1936 ret = SSH_ERR_INVALID_FORMAT; 1937 goto out; 1938 } 1939 } 1940 1941 /* Parse CA key and check signature */ 1942 if (sshkey_from_blob_internal(ca, &key->cert->signature_key, 0) != 0) { 1943 ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 1944 goto out; 1945 } 1946 if (!sshkey_type_is_valid_ca(key->cert->signature_key->type)) { 1947 ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 1948 goto out; 1949 } 1950 if ((ret = sshkey_verify(key->cert->signature_key, sig, slen, 1951 sshbuf_ptr(key->cert->certblob), signed_len, NULL, 0, NULL)) != 0) 1952 goto out; 1953 if ((ret = sshkey_get_sigtype(sig, slen, 1954 &key->cert->signature_type)) != 0) 1955 goto out; 1956 1957 /* Success */ 1958 ret = 0; 1959 out: 1960 sshbuf_free(ca); 1961 sshbuf_free(crit); 1962 sshbuf_free(exts); 1963 sshbuf_free(principals); 1964 free(sig); 1965 return ret; 1966 } 1967 1968 int 1969 sshkey_deserialize_sk(struct sshbuf *b, struct sshkey *key) 1970 { 1971 /* Parse additional security-key application string */ 1972 if (sshbuf_get_cstring(b, &key->sk_application, NULL) != 0) 1973 return SSH_ERR_INVALID_FORMAT; 1974 return 0; 1975 } 1976 1977 static int 1978 sshkey_from_blob_internal(struct sshbuf *b, struct sshkey **keyp, 1979 int allow_cert) 1980 { 1981 int type, ret = SSH_ERR_INTERNAL_ERROR; 1982 char *ktype = NULL; 1983 struct sshkey *key = NULL; 1984 struct sshbuf *copy; 1985 const struct sshkey_impl *impl; 1986 1987 #ifdef DEBUG_PK /* XXX */ 1988 sshbuf_dump(b, stderr); 1989 #endif 1990 if (keyp != NULL) 1991 *keyp = NULL; 1992 if ((copy = sshbuf_fromb(b)) == NULL) { 1993 ret = SSH_ERR_ALLOC_FAIL; 1994 goto out; 1995 } 1996 if (sshbuf_get_cstring(b, &ktype, NULL) != 0) { 1997 ret = SSH_ERR_INVALID_FORMAT; 1998 goto out; 1999 } 2000 2001 type = sshkey_type_from_name(ktype); 2002 if (!allow_cert && sshkey_type_is_cert(type)) { 2003 ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 2004 goto out; 2005 } 2006 if ((impl = sshkey_impl_from_type(type)) == NULL) { 2007 ret = SSH_ERR_KEY_TYPE_UNKNOWN; 2008 goto out; 2009 } 2010 if ((key = sshkey_new(type)) == NULL) { 2011 ret = SSH_ERR_ALLOC_FAIL; 2012 goto out; 2013 } 2014 if (sshkey_type_is_cert(type)) { 2015 /* Skip nonce that precedes all certificates */ 2016 if (sshbuf_get_string_direct(b, NULL, NULL) != 0) { 2017 ret = SSH_ERR_INVALID_FORMAT; 2018 goto out; 2019 } 2020 } 2021 if ((ret = impl->funcs->deserialize_public(ktype, b, key)) != 0) 2022 goto out; 2023 2024 /* Parse certificate potion */ 2025 if (sshkey_is_cert(key) && (ret = cert_parse(b, key, copy)) != 0) 2026 goto out; 2027 2028 if (key != NULL && sshbuf_len(b) != 0) { 2029 ret = SSH_ERR_INVALID_FORMAT; 2030 goto out; 2031 } 2032 ret = 0; 2033 if (keyp != NULL) { 2034 *keyp = key; 2035 key = NULL; 2036 } 2037 out: 2038 sshbuf_free(copy); 2039 sshkey_free(key); 2040 free(ktype); 2041 return ret; 2042 } 2043 2044 int 2045 sshkey_from_blob(const u_char *blob, size_t blen, struct sshkey **keyp) 2046 { 2047 struct sshbuf *b; 2048 int r; 2049 2050 if ((b = sshbuf_from(blob, blen)) == NULL) 2051 return SSH_ERR_ALLOC_FAIL; 2052 r = sshkey_from_blob_internal(b, keyp, 1); 2053 sshbuf_free(b); 2054 return r; 2055 } 2056 2057 int 2058 sshkey_fromb(struct sshbuf *b, struct sshkey **keyp) 2059 { 2060 return sshkey_from_blob_internal(b, keyp, 1); 2061 } 2062 2063 int 2064 sshkey_froms(struct sshbuf *buf, struct sshkey **keyp) 2065 { 2066 struct sshbuf *b; 2067 int r; 2068 2069 if ((r = sshbuf_froms(buf, &b)) != 0) 2070 return r; 2071 r = sshkey_from_blob_internal(b, keyp, 1); 2072 sshbuf_free(b); 2073 return r; 2074 } 2075 2076 int 2077 sshkey_get_sigtype(const u_char *sig, size_t siglen, char **sigtypep) 2078 { 2079 int r; 2080 struct sshbuf *b = NULL; 2081 char *sigtype = NULL; 2082 2083 if (sigtypep != NULL) 2084 *sigtypep = NULL; 2085 if ((b = sshbuf_from(sig, siglen)) == NULL) 2086 return SSH_ERR_ALLOC_FAIL; 2087 if ((r = sshbuf_get_cstring(b, &sigtype, NULL)) != 0) 2088 goto out; 2089 /* success */ 2090 if (sigtypep != NULL) { 2091 *sigtypep = sigtype; 2092 sigtype = NULL; 2093 } 2094 r = 0; 2095 out: 2096 free(sigtype); 2097 sshbuf_free(b); 2098 return r; 2099 } 2100 2101 /* 2102 * 2103 * Checks whether a certificate's signature type is allowed. 2104 * Returns 0 (success) if the certificate signature type appears in the 2105 * "allowed" pattern-list, or the key is not a certificate to begin with. 2106 * Otherwise returns a ssherr.h code. 2107 */ 2108 int 2109 sshkey_check_cert_sigtype(const struct sshkey *key, const char *allowed) 2110 { 2111 if (key == NULL || allowed == NULL) 2112 return SSH_ERR_INVALID_ARGUMENT; 2113 if (!sshkey_type_is_cert(key->type)) 2114 return 0; 2115 if (key->cert == NULL || key->cert->signature_type == NULL) 2116 return SSH_ERR_INVALID_ARGUMENT; 2117 if (match_pattern_list(key->cert->signature_type, allowed, 0) != 1) 2118 return SSH_ERR_SIGN_ALG_UNSUPPORTED; 2119 return 0; 2120 } 2121 2122 /* 2123 * Returns the expected signature algorithm for a given public key algorithm. 2124 */ 2125 const char * 2126 sshkey_sigalg_by_name(const char *name) 2127 { 2128 const struct sshkey_impl *impl; 2129 int i; 2130 2131 for (i = 0; keyimpls[i] != NULL; i++) { 2132 impl = keyimpls[i]; 2133 if (strcmp(impl->name, name) != 0) 2134 continue; 2135 if (impl->sigalg != NULL) 2136 return impl->sigalg; 2137 if (!impl->cert) 2138 return impl->name; 2139 return sshkey_ssh_name_from_type_nid( 2140 sshkey_type_plain(impl->type), impl->nid); 2141 } 2142 return NULL; 2143 } 2144 2145 /* 2146 * Verifies that the signature algorithm appearing inside the signature blob 2147 * matches that which was requested. 2148 */ 2149 int 2150 sshkey_check_sigtype(const u_char *sig, size_t siglen, 2151 const char *requested_alg) 2152 { 2153 const char *expected_alg; 2154 char *sigtype = NULL; 2155 int r; 2156 2157 if (requested_alg == NULL) 2158 return 0; 2159 if ((expected_alg = sshkey_sigalg_by_name(requested_alg)) == NULL) 2160 return SSH_ERR_INVALID_ARGUMENT; 2161 if ((r = sshkey_get_sigtype(sig, siglen, &sigtype)) != 0) 2162 return r; 2163 r = strcmp(expected_alg, sigtype) == 0; 2164 free(sigtype); 2165 return r ? 0 : SSH_ERR_SIGN_ALG_UNSUPPORTED; 2166 } 2167 2168 int 2169 sshkey_sign(struct sshkey *key, 2170 u_char **sigp, size_t *lenp, 2171 const u_char *data, size_t datalen, 2172 const char *alg, const char *sk_provider, const char *sk_pin, u_int compat) 2173 { 2174 int was_shielded = sshkey_is_shielded(key); 2175 int r2, r = SSH_ERR_INTERNAL_ERROR; 2176 const struct sshkey_impl *impl; 2177 2178 if (sigp != NULL) 2179 *sigp = NULL; 2180 if (lenp != NULL) 2181 *lenp = 0; 2182 if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE) 2183 return SSH_ERR_INVALID_ARGUMENT; 2184 if ((impl = sshkey_impl_from_key(key)) == NULL) 2185 return SSH_ERR_KEY_TYPE_UNKNOWN; 2186 if ((r = sshkey_unshield_private(key)) != 0) 2187 return r; 2188 if (sshkey_is_sk(key)) { 2189 r = sshsk_sign(sk_provider, key, sigp, lenp, data, 2190 datalen, compat, sk_pin); 2191 } else if ((key->flags & SSHKEY_FLAG_EXT) != 0) { 2192 r = pkcs11_sign(key, sigp, lenp, data, datalen, 2193 alg, sk_provider, sk_pin, compat); 2194 } else { 2195 if (impl->funcs->sign == NULL) 2196 r = SSH_ERR_SIGN_ALG_UNSUPPORTED; 2197 else { 2198 r = impl->funcs->sign(key, sigp, lenp, data, datalen, 2199 alg, sk_provider, sk_pin, compat); 2200 } 2201 } 2202 if (was_shielded && (r2 = sshkey_shield_private(key)) != 0) 2203 return r2; 2204 return r; 2205 } 2206 2207 /* 2208 * ssh_key_verify returns 0 for a correct signature and < 0 on error. 2209 * If "alg" specified, then the signature must use that algorithm. 2210 */ 2211 int 2212 sshkey_verify(const struct sshkey *key, 2213 const u_char *sig, size_t siglen, 2214 const u_char *data, size_t dlen, const char *alg, u_int compat, 2215 struct sshkey_sig_details **detailsp) 2216 { 2217 const struct sshkey_impl *impl; 2218 2219 if (detailsp != NULL) 2220 *detailsp = NULL; 2221 if (siglen == 0 || dlen > SSH_KEY_MAX_SIGN_DATA_SIZE) 2222 return SSH_ERR_INVALID_ARGUMENT; 2223 if ((impl = sshkey_impl_from_key(key)) == NULL) 2224 return SSH_ERR_KEY_TYPE_UNKNOWN; 2225 return impl->funcs->verify(key, sig, siglen, data, dlen, 2226 alg, compat, detailsp); 2227 } 2228 2229 /* Convert a plain key to their _CERT equivalent */ 2230 int 2231 sshkey_to_certified(struct sshkey *k) 2232 { 2233 int newtype; 2234 2235 if ((newtype = sshkey_type_certified(k->type)) == -1) 2236 return SSH_ERR_INVALID_ARGUMENT; 2237 if ((k->cert = cert_new()) == NULL) 2238 return SSH_ERR_ALLOC_FAIL; 2239 k->type = newtype; 2240 return 0; 2241 } 2242 2243 /* Convert a certificate to its raw key equivalent */ 2244 int 2245 sshkey_drop_cert(struct sshkey *k) 2246 { 2247 if (!sshkey_type_is_cert(k->type)) 2248 return SSH_ERR_KEY_TYPE_UNKNOWN; 2249 cert_free(k->cert); 2250 k->cert = NULL; 2251 k->type = sshkey_type_plain(k->type); 2252 return 0; 2253 } 2254 2255 /* Sign a certified key, (re-)generating the signed certblob. */ 2256 int 2257 sshkey_certify_custom(struct sshkey *k, struct sshkey *ca, const char *alg, 2258 const char *sk_provider, const char *sk_pin, 2259 sshkey_certify_signer *signer, void *signer_ctx) 2260 { 2261 const struct sshkey_impl *impl; 2262 struct sshbuf *principals = NULL; 2263 u_char *ca_blob = NULL, *sig_blob = NULL, nonce[32]; 2264 size_t i, ca_len, sig_len; 2265 int ret = SSH_ERR_INTERNAL_ERROR; 2266 struct sshbuf *cert = NULL; 2267 char *sigtype = NULL; 2268 2269 if (k == NULL || k->cert == NULL || 2270 k->cert->certblob == NULL || ca == NULL) 2271 return SSH_ERR_INVALID_ARGUMENT; 2272 if (!sshkey_is_cert(k)) 2273 return SSH_ERR_KEY_TYPE_UNKNOWN; 2274 if (!sshkey_type_is_valid_ca(ca->type)) 2275 return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 2276 if ((impl = sshkey_impl_from_key(k)) == NULL) 2277 return SSH_ERR_INTERNAL_ERROR; 2278 2279 /* 2280 * If no alg specified as argument but a signature_type was set, 2281 * then prefer that. If both were specified, then they must match. 2282 */ 2283 if (alg == NULL) 2284 alg = k->cert->signature_type; 2285 else if (k->cert->signature_type != NULL && 2286 strcmp(alg, k->cert->signature_type) != 0) 2287 return SSH_ERR_INVALID_ARGUMENT; 2288 2289 /* 2290 * If no signing algorithm or signature_type was specified and we're 2291 * using a RSA key, then default to a good signature algorithm. 2292 */ 2293 if (alg == NULL && ca->type == KEY_RSA) 2294 alg = "rsa-sha2-512"; 2295 2296 if ((ret = sshkey_to_blob(ca, &ca_blob, &ca_len)) != 0) 2297 return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 2298 2299 cert = k->cert->certblob; /* for readability */ 2300 sshbuf_reset(cert); 2301 if ((ret = sshbuf_put_cstring(cert, sshkey_ssh_name(k))) != 0) 2302 goto out; 2303 2304 /* -v01 certs put nonce first */ 2305 arc4random_buf(&nonce, sizeof(nonce)); 2306 if ((ret = sshbuf_put_string(cert, nonce, sizeof(nonce))) != 0) 2307 goto out; 2308 2309 /* Public key next */ 2310 if ((ret = impl->funcs->serialize_public(k, cert, 2311 SSHKEY_SERIALIZE_DEFAULT)) != 0) 2312 goto out; 2313 2314 /* Then remaining cert fields */ 2315 if ((ret = sshbuf_put_u64(cert, k->cert->serial)) != 0 || 2316 (ret = sshbuf_put_u32(cert, k->cert->type)) != 0 || 2317 (ret = sshbuf_put_cstring(cert, k->cert->key_id)) != 0) 2318 goto out; 2319 2320 if ((principals = sshbuf_new()) == NULL) { 2321 ret = SSH_ERR_ALLOC_FAIL; 2322 goto out; 2323 } 2324 for (i = 0; i < k->cert->nprincipals; i++) { 2325 if ((ret = sshbuf_put_cstring(principals, 2326 k->cert->principals[i])) != 0) 2327 goto out; 2328 } 2329 if ((ret = sshbuf_put_stringb(cert, principals)) != 0 || 2330 (ret = sshbuf_put_u64(cert, k->cert->valid_after)) != 0 || 2331 (ret = sshbuf_put_u64(cert, k->cert->valid_before)) != 0 || 2332 (ret = sshbuf_put_stringb(cert, k->cert->critical)) != 0 || 2333 (ret = sshbuf_put_stringb(cert, k->cert->extensions)) != 0 || 2334 (ret = sshbuf_put_string(cert, NULL, 0)) != 0 || /* Reserved */ 2335 (ret = sshbuf_put_string(cert, ca_blob, ca_len)) != 0) 2336 goto out; 2337 2338 /* Sign the whole mess */ 2339 if ((ret = signer(ca, &sig_blob, &sig_len, sshbuf_ptr(cert), 2340 sshbuf_len(cert), alg, sk_provider, sk_pin, 0, signer_ctx)) != 0) 2341 goto out; 2342 /* Check and update signature_type against what was actually used */ 2343 if ((ret = sshkey_get_sigtype(sig_blob, sig_len, &sigtype)) != 0) 2344 goto out; 2345 if (alg != NULL && strcmp(alg, sigtype) != 0) { 2346 ret = SSH_ERR_SIGN_ALG_UNSUPPORTED; 2347 goto out; 2348 } 2349 if (k->cert->signature_type == NULL) { 2350 k->cert->signature_type = sigtype; 2351 sigtype = NULL; 2352 } 2353 /* Append signature and we are done */ 2354 if ((ret = sshbuf_put_string(cert, sig_blob, sig_len)) != 0) 2355 goto out; 2356 ret = 0; 2357 out: 2358 if (ret != 0) 2359 sshbuf_reset(cert); 2360 free(sig_blob); 2361 free(ca_blob); 2362 free(sigtype); 2363 sshbuf_free(principals); 2364 return ret; 2365 } 2366 2367 static int 2368 default_key_sign(struct sshkey *key, u_char **sigp, size_t *lenp, 2369 const u_char *data, size_t datalen, 2370 const char *alg, const char *sk_provider, const char *sk_pin, 2371 u_int compat, void *ctx) 2372 { 2373 if (ctx != NULL) 2374 return SSH_ERR_INVALID_ARGUMENT; 2375 return sshkey_sign(key, sigp, lenp, data, datalen, alg, 2376 sk_provider, sk_pin, compat); 2377 } 2378 2379 int 2380 sshkey_certify(struct sshkey *k, struct sshkey *ca, const char *alg, 2381 const char *sk_provider, const char *sk_pin) 2382 { 2383 return sshkey_certify_custom(k, ca, alg, sk_provider, sk_pin, 2384 default_key_sign, NULL); 2385 } 2386 2387 int 2388 sshkey_cert_check_authority(const struct sshkey *k, 2389 int want_host, int require_principal, int wildcard_pattern, 2390 uint64_t verify_time, const char *name, const char **reason) 2391 { 2392 u_int i, principal_matches; 2393 2394 if (reason == NULL) 2395 return SSH_ERR_INVALID_ARGUMENT; 2396 if (!sshkey_is_cert(k)) { 2397 *reason = "Key is not a certificate"; 2398 return SSH_ERR_KEY_CERT_INVALID; 2399 } 2400 if (want_host) { 2401 if (k->cert->type != SSH2_CERT_TYPE_HOST) { 2402 *reason = "Certificate invalid: not a host certificate"; 2403 return SSH_ERR_KEY_CERT_INVALID; 2404 } 2405 } else { 2406 if (k->cert->type != SSH2_CERT_TYPE_USER) { 2407 *reason = "Certificate invalid: not a user certificate"; 2408 return SSH_ERR_KEY_CERT_INVALID; 2409 } 2410 } 2411 if (verify_time < k->cert->valid_after) { 2412 *reason = "Certificate invalid: not yet valid"; 2413 return SSH_ERR_KEY_CERT_INVALID; 2414 } 2415 if (verify_time >= k->cert->valid_before) { 2416 *reason = "Certificate invalid: expired"; 2417 return SSH_ERR_KEY_CERT_INVALID; 2418 } 2419 if (k->cert->nprincipals == 0) { 2420 if (require_principal) { 2421 *reason = "Certificate lacks principal list"; 2422 return SSH_ERR_KEY_CERT_INVALID; 2423 } 2424 } else if (name != NULL) { 2425 principal_matches = 0; 2426 for (i = 0; i < k->cert->nprincipals; i++) { 2427 if (wildcard_pattern) { 2428 if (match_pattern(k->cert->principals[i], 2429 name)) { 2430 principal_matches = 1; 2431 break; 2432 } 2433 } else if (strcmp(name, k->cert->principals[i]) == 0) { 2434 principal_matches = 1; 2435 break; 2436 } 2437 } 2438 if (!principal_matches) { 2439 *reason = "Certificate invalid: name is not a listed " 2440 "principal"; 2441 return SSH_ERR_KEY_CERT_INVALID; 2442 } 2443 } 2444 return 0; 2445 } 2446 2447 int 2448 sshkey_cert_check_authority_now(const struct sshkey *k, 2449 int want_host, int require_principal, int wildcard_pattern, 2450 const char *name, const char **reason) 2451 { 2452 time_t now; 2453 2454 if ((now = time(NULL)) < 0) { 2455 /* yikes - system clock before epoch! */ 2456 *reason = "Certificate invalid: not yet valid"; 2457 return SSH_ERR_KEY_CERT_INVALID; 2458 } 2459 return sshkey_cert_check_authority(k, want_host, require_principal, 2460 wildcard_pattern, (uint64_t)now, name, reason); 2461 } 2462 2463 int 2464 sshkey_cert_check_host(const struct sshkey *key, const char *host, 2465 int wildcard_principals, const char *ca_sign_algorithms, 2466 const char **reason) 2467 { 2468 int r; 2469 2470 if ((r = sshkey_cert_check_authority_now(key, 1, 0, wildcard_principals, 2471 host, reason)) != 0) 2472 return r; 2473 if (sshbuf_len(key->cert->critical) != 0) { 2474 *reason = "Certificate contains unsupported critical options"; 2475 return SSH_ERR_KEY_CERT_INVALID; 2476 } 2477 if (ca_sign_algorithms != NULL && 2478 (r = sshkey_check_cert_sigtype(key, ca_sign_algorithms)) != 0) { 2479 *reason = "Certificate signed with disallowed algorithm"; 2480 return SSH_ERR_KEY_CERT_INVALID; 2481 } 2482 return 0; 2483 } 2484 2485 size_t 2486 sshkey_format_cert_validity(const struct sshkey_cert *cert, char *s, size_t l) 2487 { 2488 char from[32], to[32], ret[128]; 2489 2490 *from = *to = '\0'; 2491 if (cert->valid_after == 0 && 2492 cert->valid_before == 0xffffffffffffffffULL) 2493 return strlcpy(s, "forever", l); 2494 2495 if (cert->valid_after != 0) 2496 format_absolute_time(cert->valid_after, from, sizeof(from)); 2497 if (cert->valid_before != 0xffffffffffffffffULL) 2498 format_absolute_time(cert->valid_before, to, sizeof(to)); 2499 2500 if (cert->valid_after == 0) 2501 snprintf(ret, sizeof(ret), "before %s", to); 2502 else if (cert->valid_before == 0xffffffffffffffffULL) 2503 snprintf(ret, sizeof(ret), "after %s", from); 2504 else 2505 snprintf(ret, sizeof(ret), "from %s to %s", from, to); 2506 2507 return strlcpy(s, ret, l); 2508 } 2509 2510 /* Common serialization for FIDO private keys */ 2511 int 2512 sshkey_serialize_private_sk(const struct sshkey *key, struct sshbuf *b) 2513 { 2514 int r; 2515 2516 if ((r = sshbuf_put_cstring(b, key->sk_application)) != 0 || 2517 (r = sshbuf_put_u8(b, key->sk_flags)) != 0 || 2518 (r = sshbuf_put_stringb(b, key->sk_key_handle)) != 0 || 2519 (r = sshbuf_put_stringb(b, key->sk_reserved)) != 0) 2520 return r; 2521 2522 return 0; 2523 } 2524 2525 static int 2526 sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf, 2527 enum sshkey_serialize_rep opts) 2528 { 2529 int r = SSH_ERR_INTERNAL_ERROR; 2530 int was_shielded = sshkey_is_shielded(key); 2531 struct sshbuf *b = NULL; 2532 const struct sshkey_impl *impl; 2533 2534 if ((impl = sshkey_impl_from_key(key)) == NULL) 2535 return SSH_ERR_INTERNAL_ERROR; 2536 if ((r = sshkey_unshield_private(key)) != 0) 2537 return r; 2538 if ((b = sshbuf_new()) == NULL) 2539 return SSH_ERR_ALLOC_FAIL; 2540 if ((r = sshbuf_put_cstring(b, sshkey_ssh_name(key))) != 0) 2541 goto out; 2542 if (sshkey_is_cert(key)) { 2543 if (key->cert == NULL || 2544 sshbuf_len(key->cert->certblob) == 0) { 2545 r = SSH_ERR_INVALID_ARGUMENT; 2546 goto out; 2547 } 2548 if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0) 2549 goto out; 2550 } 2551 if ((r = impl->funcs->serialize_private(key, b, opts)) != 0) 2552 goto out; 2553 2554 /* 2555 * success (but we still need to append the output to buf after 2556 * possibly re-shielding the private key) 2557 */ 2558 r = 0; 2559 out: 2560 if (was_shielded) 2561 r = sshkey_shield_private(key); 2562 if (r == 0) 2563 r = sshbuf_putb(buf, b); 2564 sshbuf_free(b); 2565 2566 return r; 2567 } 2568 2569 int 2570 sshkey_private_serialize(struct sshkey *key, struct sshbuf *b) 2571 { 2572 return sshkey_private_serialize_opt(key, b, 2573 SSHKEY_SERIALIZE_DEFAULT); 2574 } 2575 2576 2577 /* Shared deserialization of FIDO private key components */ 2578 int 2579 sshkey_private_deserialize_sk(struct sshbuf *buf, struct sshkey *k) 2580 { 2581 int r; 2582 2583 if ((k->sk_key_handle = sshbuf_new()) == NULL || 2584 (k->sk_reserved = sshbuf_new()) == NULL) 2585 return SSH_ERR_ALLOC_FAIL; 2586 if ((r = sshbuf_get_cstring(buf, &k->sk_application, NULL)) != 0 || 2587 (r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 || 2588 (r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 || 2589 (r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0) 2590 return r; 2591 2592 return 0; 2593 } 2594 2595 int 2596 sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp) 2597 { 2598 const struct sshkey_impl *impl; 2599 char *tname = NULL; 2600 char *expect_sk_application = NULL; 2601 u_char *expect_ed25519_pk = NULL; 2602 struct sshkey *k = NULL; 2603 int type, r = SSH_ERR_INTERNAL_ERROR; 2604 2605 if (kp != NULL) 2606 *kp = NULL; 2607 if ((r = sshbuf_get_cstring(buf, &tname, NULL)) != 0) 2608 goto out; 2609 type = sshkey_type_from_name(tname); 2610 if (sshkey_type_is_cert(type)) { 2611 /* 2612 * Certificate key private keys begin with the certificate 2613 * itself. Make sure this matches the type of the enclosing 2614 * private key. 2615 */ 2616 if ((r = sshkey_froms(buf, &k)) != 0) 2617 goto out; 2618 if (k->type != type) { 2619 r = SSH_ERR_KEY_CERT_MISMATCH; 2620 goto out; 2621 } 2622 /* For ECDSA keys, the group must match too */ 2623 if (k->type == KEY_ECDSA && 2624 k->ecdsa_nid != sshkey_ecdsa_nid_from_name(tname)) { 2625 r = SSH_ERR_KEY_CERT_MISMATCH; 2626 goto out; 2627 } 2628 /* 2629 * Several fields are redundant between certificate and 2630 * private key body, we require these to match. 2631 */ 2632 expect_sk_application = k->sk_application; 2633 expect_ed25519_pk = k->ed25519_pk; 2634 k->sk_application = NULL; 2635 k->ed25519_pk = NULL; 2636 } else { 2637 if ((k = sshkey_new(type)) == NULL) { 2638 r = SSH_ERR_ALLOC_FAIL; 2639 goto out; 2640 } 2641 } 2642 if ((impl = sshkey_impl_from_type(type)) == NULL) { 2643 r = SSH_ERR_INTERNAL_ERROR; 2644 goto out; 2645 } 2646 if ((r = impl->funcs->deserialize_private(tname, buf, k)) != 0) 2647 goto out; 2648 2649 if ((expect_sk_application != NULL && (k->sk_application == NULL || 2650 strcmp(expect_sk_application, k->sk_application) != 0)) || 2651 (expect_ed25519_pk != NULL && (k->ed25519_pk == NULL || 2652 memcmp(expect_ed25519_pk, k->ed25519_pk, ED25519_PK_SZ) != 0))) { 2653 r = SSH_ERR_KEY_CERT_MISMATCH; 2654 goto out; 2655 } 2656 /* success */ 2657 r = 0; 2658 if (kp != NULL) { 2659 *kp = k; 2660 k = NULL; 2661 } 2662 out: 2663 free(tname); 2664 sshkey_free(k); 2665 free(expect_sk_application); 2666 free(expect_ed25519_pk); 2667 return r; 2668 } 2669 2670 #if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) 2671 int 2672 sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public) 2673 { 2674 EC_POINT *nq = NULL; 2675 BIGNUM *order = NULL, *x = NULL, *y = NULL, *tmp = NULL; 2676 int ret = SSH_ERR_KEY_INVALID_EC_VALUE; 2677 2678 /* 2679 * NB. This assumes OpenSSL has already verified that the public 2680 * point lies on the curve. This is done by EC_POINT_oct2point() 2681 * implicitly calling EC_POINT_is_on_curve(). If this code is ever 2682 * reachable with public points not unmarshalled using 2683 * EC_POINT_oct2point then the caller will need to explicitly check. 2684 */ 2685 2686 /* Q != infinity */ 2687 if (EC_POINT_is_at_infinity(group, public)) 2688 goto out; 2689 2690 if ((x = BN_new()) == NULL || 2691 (y = BN_new()) == NULL || 2692 (order = BN_new()) == NULL || 2693 (tmp = BN_new()) == NULL) { 2694 ret = SSH_ERR_ALLOC_FAIL; 2695 goto out; 2696 } 2697 2698 /* log2(x) > log2(order)/2, log2(y) > log2(order)/2 */ 2699 if (EC_GROUP_get_order(group, order, NULL) != 1 || 2700 EC_POINT_get_affine_coordinates(group, public, x, y, NULL) != 1) { 2701 ret = SSH_ERR_LIBCRYPTO_ERROR; 2702 goto out; 2703 } 2704 if (BN_num_bits(x) <= BN_num_bits(order) / 2 || 2705 BN_num_bits(y) <= BN_num_bits(order) / 2) 2706 goto out; 2707 2708 /* nQ == infinity (n == order of subgroup) */ 2709 if ((nq = EC_POINT_new(group)) == NULL) { 2710 ret = SSH_ERR_ALLOC_FAIL; 2711 goto out; 2712 } 2713 if (EC_POINT_mul(group, nq, NULL, public, order, NULL) != 1) { 2714 ret = SSH_ERR_LIBCRYPTO_ERROR; 2715 goto out; 2716 } 2717 if (EC_POINT_is_at_infinity(group, nq) != 1) 2718 goto out; 2719 2720 /* x < order - 1, y < order - 1 */ 2721 if (!BN_sub(tmp, order, BN_value_one())) { 2722 ret = SSH_ERR_LIBCRYPTO_ERROR; 2723 goto out; 2724 } 2725 if (BN_cmp(x, tmp) >= 0 || BN_cmp(y, tmp) >= 0) 2726 goto out; 2727 ret = 0; 2728 out: 2729 BN_clear_free(x); 2730 BN_clear_free(y); 2731 BN_clear_free(order); 2732 BN_clear_free(tmp); 2733 EC_POINT_free(nq); 2734 return ret; 2735 } 2736 2737 int 2738 sshkey_ec_validate_private(const EC_KEY *key) 2739 { 2740 BIGNUM *order = NULL, *tmp = NULL; 2741 int ret = SSH_ERR_KEY_INVALID_EC_VALUE; 2742 2743 if ((order = BN_new()) == NULL || (tmp = BN_new()) == NULL) { 2744 ret = SSH_ERR_ALLOC_FAIL; 2745 goto out; 2746 } 2747 2748 /* log2(private) > log2(order)/2 */ 2749 if (EC_GROUP_get_order(EC_KEY_get0_group(key), order, NULL) != 1) { 2750 ret = SSH_ERR_LIBCRYPTO_ERROR; 2751 goto out; 2752 } 2753 if (BN_num_bits(EC_KEY_get0_private_key(key)) <= 2754 BN_num_bits(order) / 2) 2755 goto out; 2756 2757 /* private < order - 1 */ 2758 if (!BN_sub(tmp, order, BN_value_one())) { 2759 ret = SSH_ERR_LIBCRYPTO_ERROR; 2760 goto out; 2761 } 2762 if (BN_cmp(EC_KEY_get0_private_key(key), tmp) >= 0) 2763 goto out; 2764 ret = 0; 2765 out: 2766 BN_clear_free(order); 2767 BN_clear_free(tmp); 2768 return ret; 2769 } 2770 2771 void 2772 sshkey_dump_ec_point(const EC_GROUP *group, const EC_POINT *point) 2773 { 2774 BIGNUM *x = NULL, *y = NULL; 2775 2776 if (point == NULL) { 2777 fputs("point=(NULL)\n", stderr); 2778 return; 2779 } 2780 if ((x = BN_new()) == NULL || (y = BN_new()) == NULL) { 2781 fprintf(stderr, "%s: BN_new failed\n", __func__); 2782 goto out; 2783 } 2784 if (EC_POINT_get_affine_coordinates(group, point, x, y, NULL) != 1) { 2785 fprintf(stderr, "%s: EC_POINT_get_affine_coordinates\n", 2786 __func__); 2787 goto out; 2788 } 2789 fputs("x=", stderr); 2790 BN_print_fp(stderr, x); 2791 fputs("\ny=", stderr); 2792 BN_print_fp(stderr, y); 2793 fputs("\n", stderr); 2794 out: 2795 BN_clear_free(x); 2796 BN_clear_free(y); 2797 } 2798 2799 void 2800 sshkey_dump_ec_key(const EC_KEY *key) 2801 { 2802 const BIGNUM *exponent; 2803 2804 sshkey_dump_ec_point(EC_KEY_get0_group(key), 2805 EC_KEY_get0_public_key(key)); 2806 fputs("exponent=", stderr); 2807 if ((exponent = EC_KEY_get0_private_key(key)) == NULL) 2808 fputs("(NULL)", stderr); 2809 else 2810 BN_print_fp(stderr, EC_KEY_get0_private_key(key)); 2811 fputs("\n", stderr); 2812 } 2813 #endif /* WITH_OPENSSL && OPENSSL_HAS_ECC */ 2814 2815 static int 2816 sshkey_private_to_blob2(struct sshkey *prv, struct sshbuf *blob, 2817 const char *passphrase, const char *comment, const char *ciphername, 2818 int rounds) 2819 { 2820 u_char *cp, *key = NULL, *pubkeyblob = NULL; 2821 u_char salt[SALT_LEN]; 2822 size_t i, pubkeylen, keylen, ivlen, blocksize, authlen; 2823 u_int check; 2824 int r = SSH_ERR_INTERNAL_ERROR; 2825 struct sshcipher_ctx *ciphercontext = NULL; 2826 const struct sshcipher *cipher; 2827 const char *kdfname = KDFNAME; 2828 struct sshbuf *encoded = NULL, *encrypted = NULL, *kdf = NULL; 2829 2830 if (rounds <= 0) 2831 rounds = DEFAULT_ROUNDS; 2832 if (passphrase == NULL || !strlen(passphrase)) { 2833 ciphername = "none"; 2834 kdfname = "none"; 2835 } else if (ciphername == NULL) 2836 ciphername = DEFAULT_CIPHERNAME; 2837 if ((cipher = cipher_by_name(ciphername)) == NULL) { 2838 r = SSH_ERR_INVALID_ARGUMENT; 2839 goto out; 2840 } 2841 2842 if ((kdf = sshbuf_new()) == NULL || 2843 (encoded = sshbuf_new()) == NULL || 2844 (encrypted = sshbuf_new()) == NULL) { 2845 r = SSH_ERR_ALLOC_FAIL; 2846 goto out; 2847 } 2848 blocksize = cipher_blocksize(cipher); 2849 keylen = cipher_keylen(cipher); 2850 ivlen = cipher_ivlen(cipher); 2851 authlen = cipher_authlen(cipher); 2852 if ((key = calloc(1, keylen + ivlen)) == NULL) { 2853 r = SSH_ERR_ALLOC_FAIL; 2854 goto out; 2855 } 2856 if (strcmp(kdfname, "bcrypt") == 0) { 2857 arc4random_buf(salt, SALT_LEN); 2858 if (bcrypt_pbkdf(passphrase, strlen(passphrase), 2859 salt, SALT_LEN, key, keylen + ivlen, rounds) < 0) { 2860 r = SSH_ERR_INVALID_ARGUMENT; 2861 goto out; 2862 } 2863 if ((r = sshbuf_put_string(kdf, salt, SALT_LEN)) != 0 || 2864 (r = sshbuf_put_u32(kdf, rounds)) != 0) 2865 goto out; 2866 } else if (strcmp(kdfname, "none") != 0) { 2867 /* Unsupported KDF type */ 2868 r = SSH_ERR_KEY_UNKNOWN_CIPHER; 2869 goto out; 2870 } 2871 if ((r = cipher_init(&ciphercontext, cipher, key, keylen, 2872 key + keylen, ivlen, 1)) != 0) 2873 goto out; 2874 2875 if ((r = sshbuf_put(encoded, AUTH_MAGIC, sizeof(AUTH_MAGIC))) != 0 || 2876 (r = sshbuf_put_cstring(encoded, ciphername)) != 0 || 2877 (r = sshbuf_put_cstring(encoded, kdfname)) != 0 || 2878 (r = sshbuf_put_stringb(encoded, kdf)) != 0 || 2879 (r = sshbuf_put_u32(encoded, 1)) != 0 || /* number of keys */ 2880 (r = sshkey_to_blob(prv, &pubkeyblob, &pubkeylen)) != 0 || 2881 (r = sshbuf_put_string(encoded, pubkeyblob, pubkeylen)) != 0) 2882 goto out; 2883 2884 /* set up the buffer that will be encrypted */ 2885 2886 /* Random check bytes */ 2887 check = arc4random(); 2888 if ((r = sshbuf_put_u32(encrypted, check)) != 0 || 2889 (r = sshbuf_put_u32(encrypted, check)) != 0) 2890 goto out; 2891 2892 /* append private key and comment*/ 2893 if ((r = sshkey_private_serialize(prv, encrypted)) != 0 || 2894 (r = sshbuf_put_cstring(encrypted, comment)) != 0) 2895 goto out; 2896 2897 /* padding */ 2898 i = 0; 2899 while (sshbuf_len(encrypted) % blocksize) { 2900 if ((r = sshbuf_put_u8(encrypted, ++i & 0xff)) != 0) 2901 goto out; 2902 } 2903 2904 /* length in destination buffer */ 2905 if ((r = sshbuf_put_u32(encoded, sshbuf_len(encrypted))) != 0) 2906 goto out; 2907 2908 /* encrypt */ 2909 if ((r = sshbuf_reserve(encoded, 2910 sshbuf_len(encrypted) + authlen, &cp)) != 0) 2911 goto out; 2912 if ((r = cipher_crypt(ciphercontext, 0, cp, 2913 sshbuf_ptr(encrypted), sshbuf_len(encrypted), 0, authlen)) != 0) 2914 goto out; 2915 2916 sshbuf_reset(blob); 2917 2918 /* assemble uuencoded key */ 2919 if ((r = sshbuf_put(blob, MARK_BEGIN, MARK_BEGIN_LEN)) != 0 || 2920 (r = sshbuf_dtob64(encoded, blob, 1)) != 0 || 2921 (r = sshbuf_put(blob, MARK_END, MARK_END_LEN)) != 0) 2922 goto out; 2923 2924 /* success */ 2925 r = 0; 2926 2927 out: 2928 sshbuf_free(kdf); 2929 sshbuf_free(encoded); 2930 sshbuf_free(encrypted); 2931 cipher_free(ciphercontext); 2932 explicit_bzero(salt, sizeof(salt)); 2933 if (key != NULL) 2934 freezero(key, keylen + ivlen); 2935 if (pubkeyblob != NULL) 2936 freezero(pubkeyblob, pubkeylen); 2937 return r; 2938 } 2939 2940 static int 2941 private2_uudecode(struct sshbuf *blob, struct sshbuf **decodedp) 2942 { 2943 const u_char *cp; 2944 size_t encoded_len; 2945 int r; 2946 u_char last; 2947 struct sshbuf *encoded = NULL, *decoded = NULL; 2948 2949 if (blob == NULL || decodedp == NULL) 2950 return SSH_ERR_INVALID_ARGUMENT; 2951 2952 *decodedp = NULL; 2953 2954 if ((encoded = sshbuf_new()) == NULL || 2955 (decoded = sshbuf_new()) == NULL) { 2956 r = SSH_ERR_ALLOC_FAIL; 2957 goto out; 2958 } 2959 2960 /* check preamble */ 2961 cp = sshbuf_ptr(blob); 2962 encoded_len = sshbuf_len(blob); 2963 if (encoded_len < (MARK_BEGIN_LEN + MARK_END_LEN) || 2964 memcmp(cp, MARK_BEGIN, MARK_BEGIN_LEN) != 0) { 2965 r = SSH_ERR_INVALID_FORMAT; 2966 goto out; 2967 } 2968 cp += MARK_BEGIN_LEN; 2969 encoded_len -= MARK_BEGIN_LEN; 2970 2971 /* Look for end marker, removing whitespace as we go */ 2972 while (encoded_len > 0) { 2973 if (*cp != '\n' && *cp != '\r') { 2974 if ((r = sshbuf_put_u8(encoded, *cp)) != 0) 2975 goto out; 2976 } 2977 last = *cp; 2978 encoded_len--; 2979 cp++; 2980 if (last == '\n') { 2981 if (encoded_len >= MARK_END_LEN && 2982 memcmp(cp, MARK_END, MARK_END_LEN) == 0) { 2983 /* \0 terminate */ 2984 if ((r = sshbuf_put_u8(encoded, 0)) != 0) 2985 goto out; 2986 break; 2987 } 2988 } 2989 } 2990 if (encoded_len == 0) { 2991 r = SSH_ERR_INVALID_FORMAT; 2992 goto out; 2993 } 2994 2995 /* decode base64 */ 2996 if ((r = sshbuf_b64tod(decoded, (char *)sshbuf_ptr(encoded))) != 0) 2997 goto out; 2998 2999 /* check magic */ 3000 if (sshbuf_len(decoded) < sizeof(AUTH_MAGIC) || 3001 memcmp(sshbuf_ptr(decoded), AUTH_MAGIC, sizeof(AUTH_MAGIC))) { 3002 r = SSH_ERR_INVALID_FORMAT; 3003 goto out; 3004 } 3005 /* success */ 3006 *decodedp = decoded; 3007 decoded = NULL; 3008 r = 0; 3009 out: 3010 sshbuf_free(encoded); 3011 sshbuf_free(decoded); 3012 return r; 3013 } 3014 3015 static int 3016 private2_decrypt(struct sshbuf *decoded, const char *passphrase, 3017 struct sshbuf **decryptedp, struct sshkey **pubkeyp) 3018 { 3019 char *ciphername = NULL, *kdfname = NULL; 3020 const struct sshcipher *cipher = NULL; 3021 int r = SSH_ERR_INTERNAL_ERROR; 3022 size_t keylen = 0, ivlen = 0, authlen = 0, slen = 0; 3023 struct sshbuf *kdf = NULL, *decrypted = NULL; 3024 struct sshcipher_ctx *ciphercontext = NULL; 3025 struct sshkey *pubkey = NULL; 3026 u_char *key = NULL, *salt = NULL, *dp; 3027 u_int blocksize, rounds, nkeys, encrypted_len, check1, check2; 3028 3029 if (decoded == NULL || decryptedp == NULL || pubkeyp == NULL) 3030 return SSH_ERR_INVALID_ARGUMENT; 3031 3032 *decryptedp = NULL; 3033 *pubkeyp = NULL; 3034 3035 if ((decrypted = sshbuf_new()) == NULL) { 3036 r = SSH_ERR_ALLOC_FAIL; 3037 goto out; 3038 } 3039 3040 /* parse public portion of key */ 3041 if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 || 3042 (r = sshbuf_get_cstring(decoded, &ciphername, NULL)) != 0 || 3043 (r = sshbuf_get_cstring(decoded, &kdfname, NULL)) != 0 || 3044 (r = sshbuf_froms(decoded, &kdf)) != 0 || 3045 (r = sshbuf_get_u32(decoded, &nkeys)) != 0) 3046 goto out; 3047 3048 if (nkeys != 1) { 3049 /* XXX only one key supported at present */ 3050 r = SSH_ERR_INVALID_FORMAT; 3051 goto out; 3052 } 3053 3054 if ((r = sshkey_froms(decoded, &pubkey)) != 0 || 3055 (r = sshbuf_get_u32(decoded, &encrypted_len)) != 0) 3056 goto out; 3057 3058 if ((cipher = cipher_by_name(ciphername)) == NULL) { 3059 r = SSH_ERR_KEY_UNKNOWN_CIPHER; 3060 goto out; 3061 } 3062 if (strcmp(kdfname, "none") != 0 && strcmp(kdfname, "bcrypt") != 0) { 3063 r = SSH_ERR_KEY_UNKNOWN_CIPHER; 3064 goto out; 3065 } 3066 if (strcmp(kdfname, "none") == 0 && strcmp(ciphername, "none") != 0) { 3067 r = SSH_ERR_INVALID_FORMAT; 3068 goto out; 3069 } 3070 if ((passphrase == NULL || strlen(passphrase) == 0) && 3071 strcmp(kdfname, "none") != 0) { 3072 /* passphrase required */ 3073 r = SSH_ERR_KEY_WRONG_PASSPHRASE; 3074 goto out; 3075 } 3076 3077 /* check size of encrypted key blob */ 3078 blocksize = cipher_blocksize(cipher); 3079 if (encrypted_len < blocksize || (encrypted_len % blocksize) != 0) { 3080 r = SSH_ERR_INVALID_FORMAT; 3081 goto out; 3082 } 3083 3084 /* setup key */ 3085 keylen = cipher_keylen(cipher); 3086 ivlen = cipher_ivlen(cipher); 3087 authlen = cipher_authlen(cipher); 3088 if ((key = calloc(1, keylen + ivlen)) == NULL) { 3089 r = SSH_ERR_ALLOC_FAIL; 3090 goto out; 3091 } 3092 if (strcmp(kdfname, "bcrypt") == 0) { 3093 if ((r = sshbuf_get_string(kdf, &salt, &slen)) != 0 || 3094 (r = sshbuf_get_u32(kdf, &rounds)) != 0) 3095 goto out; 3096 if (bcrypt_pbkdf(passphrase, strlen(passphrase), salt, slen, 3097 key, keylen + ivlen, rounds) < 0) { 3098 r = SSH_ERR_INVALID_FORMAT; 3099 goto out; 3100 } 3101 } 3102 3103 /* check that an appropriate amount of auth data is present */ 3104 if (sshbuf_len(decoded) < authlen || 3105 sshbuf_len(decoded) - authlen < encrypted_len) { 3106 r = SSH_ERR_INVALID_FORMAT; 3107 goto out; 3108 } 3109 3110 /* decrypt private portion of key */ 3111 if ((r = sshbuf_reserve(decrypted, encrypted_len, &dp)) != 0 || 3112 (r = cipher_init(&ciphercontext, cipher, key, keylen, 3113 key + keylen, ivlen, 0)) != 0) 3114 goto out; 3115 if ((r = cipher_crypt(ciphercontext, 0, dp, sshbuf_ptr(decoded), 3116 encrypted_len, 0, authlen)) != 0) { 3117 /* an integrity error here indicates an incorrect passphrase */ 3118 if (r == SSH_ERR_MAC_INVALID) 3119 r = SSH_ERR_KEY_WRONG_PASSPHRASE; 3120 goto out; 3121 } 3122 if ((r = sshbuf_consume(decoded, encrypted_len + authlen)) != 0) 3123 goto out; 3124 /* there should be no trailing data */ 3125 if (sshbuf_len(decoded) != 0) { 3126 r = SSH_ERR_INVALID_FORMAT; 3127 goto out; 3128 } 3129 3130 /* check check bytes */ 3131 if ((r = sshbuf_get_u32(decrypted, &check1)) != 0 || 3132 (r = sshbuf_get_u32(decrypted, &check2)) != 0) 3133 goto out; 3134 if (check1 != check2) { 3135 r = SSH_ERR_KEY_WRONG_PASSPHRASE; 3136 goto out; 3137 } 3138 /* success */ 3139 *decryptedp = decrypted; 3140 decrypted = NULL; 3141 *pubkeyp = pubkey; 3142 pubkey = NULL; 3143 r = 0; 3144 out: 3145 cipher_free(ciphercontext); 3146 free(ciphername); 3147 free(kdfname); 3148 sshkey_free(pubkey); 3149 if (salt != NULL) { 3150 explicit_bzero(salt, slen); 3151 free(salt); 3152 } 3153 if (key != NULL) { 3154 explicit_bzero(key, keylen + ivlen); 3155 free(key); 3156 } 3157 sshbuf_free(kdf); 3158 sshbuf_free(decrypted); 3159 return r; 3160 } 3161 3162 static int 3163 sshkey_parse_private2(struct sshbuf *blob, int type, const char *passphrase, 3164 struct sshkey **keyp, char **commentp) 3165 { 3166 char *comment = NULL; 3167 int r = SSH_ERR_INTERNAL_ERROR; 3168 struct sshbuf *decoded = NULL, *decrypted = NULL; 3169 struct sshkey *k = NULL, *pubkey = NULL; 3170 3171 if (keyp != NULL) 3172 *keyp = NULL; 3173 if (commentp != NULL) 3174 *commentp = NULL; 3175 3176 /* Undo base64 encoding and decrypt the private section */ 3177 if ((r = private2_uudecode(blob, &decoded)) != 0 || 3178 (r = private2_decrypt(decoded, passphrase, 3179 &decrypted, &pubkey)) != 0) 3180 goto out; 3181 3182 if (type != KEY_UNSPEC && 3183 sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) { 3184 r = SSH_ERR_KEY_TYPE_MISMATCH; 3185 goto out; 3186 } 3187 3188 /* Load the private key and comment */ 3189 if ((r = sshkey_private_deserialize(decrypted, &k)) != 0 || 3190 (r = sshbuf_get_cstring(decrypted, &comment, NULL)) != 0) 3191 goto out; 3192 3193 /* Check deterministic padding after private section */ 3194 if ((r = private2_check_padding(decrypted)) != 0) 3195 goto out; 3196 3197 /* Check that the public key in the envelope matches the private key */ 3198 if (!sshkey_equal(pubkey, k)) { 3199 r = SSH_ERR_INVALID_FORMAT; 3200 goto out; 3201 } 3202 3203 /* success */ 3204 r = 0; 3205 if (keyp != NULL) { 3206 *keyp = k; 3207 k = NULL; 3208 } 3209 if (commentp != NULL) { 3210 *commentp = comment; 3211 comment = NULL; 3212 } 3213 out: 3214 free(comment); 3215 sshbuf_free(decoded); 3216 sshbuf_free(decrypted); 3217 sshkey_free(k); 3218 sshkey_free(pubkey); 3219 return r; 3220 } 3221 3222 static int 3223 sshkey_parse_private2_pubkey(struct sshbuf *blob, int type, 3224 struct sshkey **keyp) 3225 { 3226 int r = SSH_ERR_INTERNAL_ERROR; 3227 struct sshbuf *decoded = NULL; 3228 struct sshkey *pubkey = NULL; 3229 u_int nkeys = 0; 3230 3231 if (keyp != NULL) 3232 *keyp = NULL; 3233 3234 if ((r = private2_uudecode(blob, &decoded)) != 0) 3235 goto out; 3236 /* parse public key from unencrypted envelope */ 3237 if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 || 3238 (r = sshbuf_skip_string(decoded)) != 0 || /* cipher */ 3239 (r = sshbuf_skip_string(decoded)) != 0 || /* KDF alg */ 3240 (r = sshbuf_skip_string(decoded)) != 0 || /* KDF hint */ 3241 (r = sshbuf_get_u32(decoded, &nkeys)) != 0) 3242 goto out; 3243 3244 if (nkeys != 1) { 3245 /* XXX only one key supported at present */ 3246 r = SSH_ERR_INVALID_FORMAT; 3247 goto out; 3248 } 3249 3250 /* Parse the public key */ 3251 if ((r = sshkey_froms(decoded, &pubkey)) != 0) 3252 goto out; 3253 3254 if (type != KEY_UNSPEC && 3255 sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) { 3256 r = SSH_ERR_KEY_TYPE_MISMATCH; 3257 goto out; 3258 } 3259 3260 /* success */ 3261 r = 0; 3262 if (keyp != NULL) { 3263 *keyp = pubkey; 3264 pubkey = NULL; 3265 } 3266 out: 3267 sshbuf_free(decoded); 3268 sshkey_free(pubkey); 3269 return r; 3270 } 3271 3272 #ifdef WITH_OPENSSL 3273 /* convert SSH v2 key to PEM or PKCS#8 format */ 3274 static int 3275 sshkey_private_to_blob_pem_pkcs8(struct sshkey *key, struct sshbuf *buf, 3276 int format, const char *_passphrase, const char *comment) 3277 { 3278 int was_shielded = sshkey_is_shielded(key); 3279 int success, r; 3280 int blen, len = strlen(_passphrase); 3281 u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL; 3282 const EVP_CIPHER *cipher = (len > 0) ? EVP_aes_128_cbc() : NULL; 3283 char *bptr; 3284 BIO *bio = NULL; 3285 struct sshbuf *blob; 3286 EVP_PKEY *pkey = NULL; 3287 3288 if (len > 0 && len <= 4) 3289 return SSH_ERR_PASSPHRASE_TOO_SHORT; 3290 if ((blob = sshbuf_new()) == NULL) 3291 return SSH_ERR_ALLOC_FAIL; 3292 if ((bio = BIO_new(BIO_s_mem())) == NULL) { 3293 r = SSH_ERR_ALLOC_FAIL; 3294 goto out; 3295 } 3296 if ((r = sshkey_unshield_private(key)) != 0) 3297 goto out; 3298 3299 switch (key->type) { 3300 #ifdef OPENSSL_HAS_ECC 3301 case KEY_ECDSA: 3302 if (format == SSHKEY_PRIVATE_PEM) { 3303 success = PEM_write_bio_ECPrivateKey(bio, 3304 EVP_PKEY_get0_EC_KEY(key->pkey), 3305 cipher, passphrase, len, NULL, NULL); 3306 } else { 3307 pkey = key->pkey; 3308 EVP_PKEY_up_ref(key->pkey); 3309 success = 1; 3310 } 3311 break; 3312 #endif 3313 case KEY_RSA: 3314 if (format == SSHKEY_PRIVATE_PEM) { 3315 success = PEM_write_bio_RSAPrivateKey(bio, 3316 EVP_PKEY_get0_RSA(key->pkey), 3317 cipher, passphrase, len, NULL, NULL); 3318 } else { 3319 pkey = key->pkey; 3320 EVP_PKEY_up_ref(key->pkey); 3321 success = 1; 3322 } 3323 break; 3324 default: 3325 success = 0; 3326 break; 3327 } 3328 if (success == 0) { 3329 r = SSH_ERR_LIBCRYPTO_ERROR; 3330 goto out; 3331 } 3332 if (format == SSHKEY_PRIVATE_PKCS8) { 3333 if ((success = PEM_write_bio_PrivateKey(bio, pkey, cipher, 3334 passphrase, len, NULL, NULL)) == 0) { 3335 r = SSH_ERR_LIBCRYPTO_ERROR; 3336 goto out; 3337 } 3338 } 3339 if ((blen = BIO_get_mem_data(bio, &bptr)) <= 0) { 3340 r = SSH_ERR_INTERNAL_ERROR; 3341 goto out; 3342 } 3343 if ((r = sshbuf_put(blob, bptr, blen)) != 0) 3344 goto out; 3345 r = 0; 3346 out: 3347 if (was_shielded) 3348 r = sshkey_shield_private(key); 3349 if (r == 0) 3350 r = sshbuf_putb(buf, blob); 3351 3352 EVP_PKEY_free(pkey); 3353 sshbuf_free(blob); 3354 BIO_free(bio); 3355 return r; 3356 } 3357 #endif /* WITH_OPENSSL */ 3358 3359 /* Serialise "key" to buffer "blob" */ 3360 int 3361 sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob, 3362 const char *passphrase, const char *comment, 3363 int format, const char *openssh_format_cipher, int openssh_format_rounds) 3364 { 3365 switch (key->type) { 3366 #ifdef WITH_OPENSSL 3367 case KEY_ECDSA: 3368 case KEY_RSA: 3369 break; /* see below */ 3370 #endif /* WITH_OPENSSL */ 3371 case KEY_ED25519: 3372 case KEY_ED25519_SK: 3373 #ifdef WITH_OPENSSL 3374 case KEY_ECDSA_SK: 3375 #endif /* WITH_OPENSSL */ 3376 return sshkey_private_to_blob2(key, blob, passphrase, 3377 comment, openssh_format_cipher, openssh_format_rounds); 3378 default: 3379 return SSH_ERR_KEY_TYPE_UNKNOWN; 3380 } 3381 3382 #ifdef WITH_OPENSSL 3383 switch (format) { 3384 case SSHKEY_PRIVATE_OPENSSH: 3385 return sshkey_private_to_blob2(key, blob, passphrase, 3386 comment, openssh_format_cipher, openssh_format_rounds); 3387 case SSHKEY_PRIVATE_PEM: 3388 case SSHKEY_PRIVATE_PKCS8: 3389 return sshkey_private_to_blob_pem_pkcs8(key, blob, 3390 format, passphrase, comment); 3391 default: 3392 return SSH_ERR_INVALID_ARGUMENT; 3393 } 3394 #endif /* WITH_OPENSSL */ 3395 } 3396 3397 #ifdef WITH_OPENSSL 3398 static int 3399 translate_libcrypto_error(unsigned long pem_err) 3400 { 3401 int pem_reason = ERR_GET_REASON(pem_err); 3402 3403 switch (ERR_GET_LIB(pem_err)) { 3404 case ERR_LIB_PEM: 3405 switch (pem_reason) { 3406 case PEM_R_BAD_PASSWORD_READ: 3407 #ifdef PEM_R_PROBLEMS_GETTING_PASSWORD 3408 case PEM_R_PROBLEMS_GETTING_PASSWORD: 3409 #endif 3410 #ifdef PEM_R_BAD_DECRYPT 3411 case PEM_R_BAD_DECRYPT: 3412 #endif 3413 return SSH_ERR_KEY_WRONG_PASSPHRASE; 3414 default: 3415 return SSH_ERR_INVALID_FORMAT; 3416 } 3417 case ERR_LIB_EVP: 3418 switch (pem_reason) { 3419 #ifdef EVP_R_BAD_DECRYPT 3420 case EVP_R_BAD_DECRYPT: 3421 return SSH_ERR_KEY_WRONG_PASSPHRASE; 3422 #endif 3423 #ifdef EVP_R_BN_DECODE_ERROR 3424 case EVP_R_BN_DECODE_ERROR: 3425 #endif 3426 case EVP_R_DECODE_ERROR: 3427 #ifdef EVP_R_PRIVATE_KEY_DECODE_ERROR 3428 case EVP_R_PRIVATE_KEY_DECODE_ERROR: 3429 #endif 3430 return SSH_ERR_INVALID_FORMAT; 3431 default: 3432 return SSH_ERR_LIBCRYPTO_ERROR; 3433 } 3434 case ERR_LIB_ASN1: 3435 return SSH_ERR_INVALID_FORMAT; 3436 } 3437 return SSH_ERR_LIBCRYPTO_ERROR; 3438 } 3439 3440 static void 3441 clear_libcrypto_errors(void) 3442 { 3443 while (ERR_get_error() != 0) 3444 ; 3445 } 3446 3447 /* 3448 * Translate OpenSSL error codes to determine whether 3449 * passphrase is required/incorrect. 3450 */ 3451 static int 3452 convert_libcrypto_error(void) 3453 { 3454 /* 3455 * Some password errors are reported at the beginning 3456 * of the error queue. 3457 */ 3458 if (translate_libcrypto_error(ERR_peek_error()) == 3459 SSH_ERR_KEY_WRONG_PASSPHRASE) 3460 return SSH_ERR_KEY_WRONG_PASSPHRASE; 3461 return translate_libcrypto_error(ERR_peek_last_error()); 3462 } 3463 3464 static int 3465 pem_passphrase_cb(char *buf, int size, int rwflag, void *u) 3466 { 3467 char *p = (char *)u; 3468 size_t len; 3469 3470 if (p == NULL || (len = strlen(p)) == 0) 3471 return -1; 3472 if (size < 0 || len > (size_t)size) 3473 return -1; 3474 memcpy(buf, p, len); 3475 return (int)len; 3476 } 3477 3478 static int 3479 sshkey_parse_private_pem_fileblob(struct sshbuf *blob, int type, 3480 const char *passphrase, struct sshkey **keyp) 3481 { 3482 EVP_PKEY *pk = NULL; 3483 struct sshkey *prv = NULL; 3484 BIO *bio = NULL; 3485 int r; 3486 RSA *rsa = NULL; 3487 EC_KEY *ecdsa = NULL; 3488 3489 if (keyp != NULL) 3490 *keyp = NULL; 3491 3492 if ((bio = BIO_new(BIO_s_mem())) == NULL || sshbuf_len(blob) > INT_MAX) 3493 return SSH_ERR_ALLOC_FAIL; 3494 if (BIO_write(bio, sshbuf_ptr(blob), sshbuf_len(blob)) != 3495 (int)sshbuf_len(blob)) { 3496 r = SSH_ERR_ALLOC_FAIL; 3497 goto out; 3498 } 3499 3500 clear_libcrypto_errors(); 3501 if ((pk = PEM_read_bio_PrivateKey(bio, NULL, pem_passphrase_cb, 3502 (char *)passphrase)) == NULL) { 3503 /* 3504 * libcrypto may return various ASN.1 errors when attempting 3505 * to parse a key with an incorrect passphrase. 3506 * Treat all format errors as "incorrect passphrase" if a 3507 * passphrase was supplied. 3508 */ 3509 if (passphrase != NULL && *passphrase != '\0') 3510 r = SSH_ERR_KEY_WRONG_PASSPHRASE; 3511 else 3512 r = convert_libcrypto_error(); 3513 goto out; 3514 } 3515 if (EVP_PKEY_base_id(pk) == EVP_PKEY_RSA && 3516 (type == KEY_UNSPEC || type == KEY_RSA)) { 3517 if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) { 3518 r = SSH_ERR_ALLOC_FAIL; 3519 goto out; 3520 } 3521 if ((rsa = EVP_PKEY_get1_RSA(pk)) == NULL) { 3522 r = SSH_ERR_LIBCRYPTO_ERROR; 3523 goto out; 3524 } 3525 prv->type = KEY_RSA; 3526 #ifdef DEBUG_PK 3527 RSA_print_fp(stderr, rsa, 8); 3528 #endif 3529 if (RSA_blinding_on(rsa, NULL) != 1 || 3530 EVP_PKEY_set1_RSA(pk, rsa) != 1) { 3531 r = SSH_ERR_LIBCRYPTO_ERROR; 3532 goto out; 3533 } 3534 EVP_PKEY_up_ref(pk); 3535 prv->pkey = pk; 3536 if ((r = sshkey_check_rsa_length(prv, 0)) != 0) 3537 goto out; 3538 #ifdef OPENSSL_HAS_ECC 3539 } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_EC && 3540 (type == KEY_UNSPEC || type == KEY_ECDSA)) { 3541 if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) { 3542 r = SSH_ERR_ALLOC_FAIL; 3543 goto out; 3544 } 3545 if ((prv->ecdsa_nid = sshkey_ecdsa_fixup_group(pk)) == -1 || 3546 (ecdsa = EVP_PKEY_get1_EC_KEY(pk)) == NULL) { 3547 r = SSH_ERR_LIBCRYPTO_ERROR; 3548 goto out; 3549 } 3550 prv->type = KEY_ECDSA; 3551 if (sshkey_curve_nid_to_name(prv->ecdsa_nid) == NULL || 3552 sshkey_ec_validate_public(EC_KEY_get0_group(ecdsa), 3553 EC_KEY_get0_public_key(ecdsa)) != 0 || 3554 sshkey_ec_validate_private(ecdsa) != 0) { 3555 r = SSH_ERR_INVALID_FORMAT; 3556 goto out; 3557 } 3558 EVP_PKEY_up_ref(pk); 3559 prv->pkey = pk; 3560 #ifdef DEBUG_PK 3561 if (prv != NULL && prv->pkey != NULL) 3562 sshkey_dump_ec_key(EVP_PKEY_get0_EC_KEY(prv->pkey)); 3563 #endif 3564 #endif /* OPENSSL_HAS_ECC */ 3565 #ifdef OPENSSL_HAS_ED25519 3566 } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_ED25519 && 3567 (type == KEY_UNSPEC || type == KEY_ED25519)) { 3568 size_t len; 3569 3570 if ((prv = sshkey_new(KEY_UNSPEC)) == NULL || 3571 (prv->ed25519_sk = calloc(1, ED25519_SK_SZ)) == NULL || 3572 (prv->ed25519_pk = calloc(1, ED25519_PK_SZ)) == NULL) { 3573 r = SSH_ERR_ALLOC_FAIL; 3574 goto out; 3575 } 3576 prv->type = KEY_ED25519; 3577 len = ED25519_PK_SZ; 3578 if (!EVP_PKEY_get_raw_public_key(pk, prv->ed25519_pk, &len)) { 3579 r = SSH_ERR_LIBCRYPTO_ERROR; 3580 goto out; 3581 } 3582 if (len != ED25519_PK_SZ) { 3583 r = SSH_ERR_INVALID_FORMAT; 3584 goto out; 3585 } 3586 len = ED25519_SK_SZ - ED25519_PK_SZ; 3587 if (!EVP_PKEY_get_raw_private_key(pk, prv->ed25519_sk, &len)) { 3588 r = SSH_ERR_LIBCRYPTO_ERROR; 3589 goto out; 3590 } 3591 if (len != ED25519_SK_SZ - ED25519_PK_SZ) { 3592 r = SSH_ERR_INVALID_FORMAT; 3593 goto out; 3594 } 3595 /* Append the public key to our private key */ 3596 memcpy(prv->ed25519_sk + (ED25519_SK_SZ - ED25519_PK_SZ), 3597 prv->ed25519_pk, ED25519_PK_SZ); 3598 #ifdef DEBUG_PK 3599 sshbuf_dump_data(prv->ed25519_sk, ED25519_SK_SZ, stderr); 3600 #endif 3601 #endif /* OPENSSL_HAS_ED25519 */ 3602 } else { 3603 r = SSH_ERR_INVALID_FORMAT; 3604 goto out; 3605 } 3606 r = 0; 3607 if (keyp != NULL) { 3608 *keyp = prv; 3609 prv = NULL; 3610 } 3611 out: 3612 BIO_free(bio); 3613 EVP_PKEY_free(pk); 3614 RSA_free(rsa); 3615 #ifdef OPENSSL_HAS_ECC 3616 EC_KEY_free(ecdsa); 3617 #endif 3618 sshkey_free(prv); 3619 return r; 3620 } 3621 #endif /* WITH_OPENSSL */ 3622 3623 int 3624 sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type, 3625 const char *passphrase, struct sshkey **keyp, char **commentp) 3626 { 3627 int r = SSH_ERR_INTERNAL_ERROR; 3628 3629 if (keyp != NULL) 3630 *keyp = NULL; 3631 if (commentp != NULL) 3632 *commentp = NULL; 3633 3634 r = sshkey_parse_private2(blob, type, passphrase, keyp, commentp); 3635 /* Only fallback to PEM parser if a format error occurred. */ 3636 if (r != SSH_ERR_INVALID_FORMAT) 3637 return r; 3638 #ifdef WITH_OPENSSL 3639 return sshkey_parse_private_pem_fileblob(blob, type, 3640 passphrase, keyp); 3641 #else 3642 return SSH_ERR_INVALID_FORMAT; 3643 #endif /* WITH_OPENSSL */ 3644 } 3645 3646 int 3647 sshkey_parse_private_fileblob(struct sshbuf *buffer, const char *passphrase, 3648 struct sshkey **keyp, char **commentp) 3649 { 3650 if (keyp != NULL) 3651 *keyp = NULL; 3652 if (commentp != NULL) 3653 *commentp = NULL; 3654 3655 return sshkey_parse_private_fileblob_type(buffer, KEY_UNSPEC, 3656 passphrase, keyp, commentp); 3657 } 3658 3659 void 3660 sshkey_sig_details_free(struct sshkey_sig_details *details) 3661 { 3662 freezero(details, sizeof(*details)); 3663 } 3664 3665 int 3666 sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob, int type, 3667 struct sshkey **pubkeyp) 3668 { 3669 int r = SSH_ERR_INTERNAL_ERROR; 3670 3671 if (pubkeyp != NULL) 3672 *pubkeyp = NULL; 3673 /* only new-format private keys bundle a public key inside */ 3674 if ((r = sshkey_parse_private2_pubkey(blob, type, pubkeyp)) != 0) 3675 return r; 3676 return 0; 3677 } 3678