1 /* $OpenBSD: sshkey.c,v 1.161 2026/02/06 22:59:18 dtucker 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 extern const struct sshkey_impl sshkey_ecdsa_sk_webauthn_cert_impl; 100 # endif /* ENABLE_SK */ 101 extern const struct sshkey_impl sshkey_ecdsa_nistp256_impl; 102 extern const struct sshkey_impl sshkey_ecdsa_nistp256_cert_impl; 103 extern const struct sshkey_impl sshkey_ecdsa_nistp384_impl; 104 extern const struct sshkey_impl sshkey_ecdsa_nistp384_cert_impl; 105 # ifdef OPENSSL_HAS_NISTP521 106 extern const struct sshkey_impl sshkey_ecdsa_nistp521_impl; 107 extern const struct sshkey_impl sshkey_ecdsa_nistp521_cert_impl; 108 # endif /* OPENSSL_HAS_NISTP521 */ 109 # endif /* OPENSSL_HAS_ECC */ 110 extern const struct sshkey_impl sshkey_rsa_impl; 111 extern const struct sshkey_impl sshkey_rsa_cert_impl; 112 extern const struct sshkey_impl sshkey_rsa_sha256_impl; 113 extern const struct sshkey_impl sshkey_rsa_sha256_cert_impl; 114 extern const struct sshkey_impl sshkey_rsa_sha512_impl; 115 extern const struct sshkey_impl sshkey_rsa_sha512_cert_impl; 116 #endif /* WITH_OPENSSL */ 117 118 const struct sshkey_impl * const keyimpls[] = { 119 &sshkey_ed25519_impl, 120 &sshkey_ed25519_cert_impl, 121 #ifdef ENABLE_SK 122 &sshkey_ed25519_sk_impl, 123 &sshkey_ed25519_sk_cert_impl, 124 #endif 125 #ifdef WITH_OPENSSL 126 # ifdef OPENSSL_HAS_ECC 127 &sshkey_ecdsa_nistp256_impl, 128 &sshkey_ecdsa_nistp256_cert_impl, 129 &sshkey_ecdsa_nistp384_impl, 130 &sshkey_ecdsa_nistp384_cert_impl, 131 # ifdef OPENSSL_HAS_NISTP521 132 &sshkey_ecdsa_nistp521_impl, 133 &sshkey_ecdsa_nistp521_cert_impl, 134 # endif /* OPENSSL_HAS_NISTP521 */ 135 # ifdef ENABLE_SK 136 &sshkey_ecdsa_sk_impl, 137 &sshkey_ecdsa_sk_cert_impl, 138 &sshkey_ecdsa_sk_webauthn_impl, 139 &sshkey_ecdsa_sk_webauthn_cert_impl, 140 # endif /* ENABLE_SK */ 141 # endif /* OPENSSL_HAS_ECC */ 142 &sshkey_rsa_impl, 143 &sshkey_rsa_cert_impl, 144 &sshkey_rsa_sha256_impl, 145 &sshkey_rsa_sha256_cert_impl, 146 &sshkey_rsa_sha512_impl, 147 &sshkey_rsa_sha512_cert_impl, 148 #endif /* WITH_OPENSSL */ 149 NULL 150 }; 151 152 static const struct sshkey_impl * 153 sshkey_impl_from_type(int type) 154 { 155 int i; 156 157 for (i = 0; keyimpls[i] != NULL; i++) { 158 if (keyimpls[i]->type == type) 159 return keyimpls[i]; 160 } 161 return NULL; 162 } 163 164 static const struct sshkey_impl * 165 sshkey_impl_from_type_nid(int type, int nid) 166 { 167 int i; 168 169 for (i = 0; keyimpls[i] != NULL; i++) { 170 if (keyimpls[i]->type == type && 171 (keyimpls[i]->nid == 0 || keyimpls[i]->nid == nid)) 172 return keyimpls[i]; 173 } 174 return NULL; 175 } 176 177 static const struct sshkey_impl * 178 sshkey_impl_from_key(const struct sshkey *k) 179 { 180 if (k == NULL) 181 return NULL; 182 return sshkey_impl_from_type_nid(k->type, k->ecdsa_nid); 183 } 184 185 const char * 186 sshkey_type(const struct sshkey *k) 187 { 188 const struct sshkey_impl *impl; 189 190 if ((impl = sshkey_impl_from_key(k)) == NULL) 191 return "unknown"; 192 return impl->shortname; 193 } 194 195 static const char * 196 sshkey_ssh_name_from_type_nid(int type, int nid) 197 { 198 const struct sshkey_impl *impl; 199 200 if ((impl = sshkey_impl_from_type_nid(type, nid)) == NULL) 201 return "ssh-unknown"; 202 return impl->name; 203 } 204 205 int 206 sshkey_type_is_cert(int type) 207 { 208 const struct sshkey_impl *impl; 209 210 if ((impl = sshkey_impl_from_type(type)) == NULL) 211 return 0; 212 return impl->cert; 213 } 214 215 const char * 216 sshkey_ssh_name(const struct sshkey *k) 217 { 218 return sshkey_ssh_name_from_type_nid(k->type, k->ecdsa_nid); 219 } 220 221 const char * 222 sshkey_ssh_name_plain(const struct sshkey *k) 223 { 224 return sshkey_ssh_name_from_type_nid(sshkey_type_plain(k->type), 225 k->ecdsa_nid); 226 } 227 228 static int 229 type_from_name(const char *name, int allow_short) 230 { 231 int i; 232 const struct sshkey_impl *impl; 233 234 for (i = 0; keyimpls[i] != NULL; i++) { 235 impl = keyimpls[i]; 236 if (impl->name != NULL && strcmp(name, impl->name) == 0) 237 return impl->type; 238 /* Only allow shortname matches for plain key types */ 239 if (allow_short && !impl->cert && impl->shortname != NULL && 240 strcasecmp(impl->shortname, name) == 0) 241 return impl->type; 242 } 243 return KEY_UNSPEC; 244 } 245 246 int 247 sshkey_type_from_name(const char *name) 248 { 249 return type_from_name(name, 0); 250 } 251 252 int 253 sshkey_type_from_shortname(const char *name) 254 { 255 return type_from_name(name, 1); 256 } 257 258 static int 259 key_type_is_ecdsa_variant(int type) 260 { 261 switch (type) { 262 case KEY_ECDSA: 263 case KEY_ECDSA_CERT: 264 case KEY_ECDSA_SK: 265 case KEY_ECDSA_SK_CERT: 266 return 1; 267 } 268 return 0; 269 } 270 271 int 272 sshkey_ecdsa_nid_from_name(const char *name) 273 { 274 int i; 275 276 for (i = 0; keyimpls[i] != NULL; i++) { 277 if (!key_type_is_ecdsa_variant(keyimpls[i]->type)) 278 continue; 279 if (keyimpls[i]->name != NULL && 280 strcmp(name, keyimpls[i]->name) == 0) 281 return keyimpls[i]->nid; 282 } 283 return -1; 284 } 285 286 int 287 sshkey_match_keyname_to_sigalgs(const char *keyname, const char *sigalgs) 288 { 289 int ktype; 290 291 if (sigalgs == NULL || *sigalgs == '\0' || 292 (ktype = sshkey_type_from_name(keyname)) == KEY_UNSPEC) 293 return 0; 294 else if (ktype == KEY_RSA) { 295 return match_pattern_list("ssh-rsa", sigalgs, 0) == 1 || 296 match_pattern_list("rsa-sha2-256", sigalgs, 0) == 1 || 297 match_pattern_list("rsa-sha2-512", sigalgs, 0) == 1; 298 } else if (ktype == KEY_RSA_CERT) { 299 return match_pattern_list("ssh-rsa-cert-v01@openssh.com", 300 sigalgs, 0) == 1 || 301 match_pattern_list("rsa-sha2-256-cert-v01@openssh.com", 302 sigalgs, 0) == 1 || 303 match_pattern_list("rsa-sha2-512-cert-v01@openssh.com", 304 sigalgs, 0) == 1; 305 } else if (ktype == KEY_ECDSA_SK) { 306 return match_pattern_list("sk-ecdsa-sha2-nistp256@openssh.com", 307 sigalgs, 0) == 1 || match_pattern_list( 308 "webauthn-sk-ecdsa-sha2-nistp256@openssh.com", 309 sigalgs, 0) == 1; 310 } else if (ktype == KEY_ECDSA_SK_CERT) { 311 return match_pattern_list( 312 "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com", 313 sigalgs, 0) == 1 || match_pattern_list( 314 "webauthn-sk-ecdsa-sha2-nistp256-cert-v01@openssh.com", 315 sigalgs, 0) == 1; 316 } else 317 return match_pattern_list(keyname, sigalgs, 0) == 1; 318 } 319 320 char * 321 sshkey_alg_list(int certs_only, int plain_only, int include_sigonly, char sep) 322 { 323 char *ret = NULL; 324 size_t i; 325 const struct sshkey_impl *impl; 326 char sep_str[2] = {sep, '\0'}; 327 328 for (i = 0; keyimpls[i] != NULL; i++) { 329 impl = keyimpls[i]; 330 if (impl->name == NULL) 331 continue; 332 if (!include_sigonly && impl->sigonly) 333 continue; 334 if ((certs_only && !impl->cert) || (plain_only && impl->cert)) 335 continue; 336 xextendf(&ret, sep_str, "%s", impl->name); 337 } 338 return ret; 339 } 340 341 int 342 sshkey_names_valid2(const char *names, int allow_wildcard, int plain_only) 343 { 344 char *s, *cp, *p; 345 const struct sshkey_impl *impl; 346 int i, type; 347 348 if (names == NULL || strcmp(names, "") == 0) 349 return 0; 350 if ((s = cp = strdup(names)) == NULL) 351 return 0; 352 for ((p = strsep(&cp, ",")); p && *p != '\0'; 353 (p = strsep(&cp, ","))) { 354 type = sshkey_type_from_name(p); 355 if (type == KEY_UNSPEC) { 356 if (allow_wildcard) { 357 /* 358 * Try matching key types against the string. 359 * If any has a positive or negative match then 360 * the component is accepted. 361 */ 362 impl = NULL; 363 for (i = 0; keyimpls[i] != NULL; i++) { 364 if (match_pattern_list( 365 keyimpls[i]->name, p, 0) != 0) { 366 impl = keyimpls[i]; 367 break; 368 } 369 } 370 if (impl != NULL) 371 continue; 372 } 373 free(s); 374 return 0; 375 } else if (plain_only && sshkey_type_is_cert(type)) { 376 free(s); 377 return 0; 378 } 379 } 380 free(s); 381 return 1; 382 } 383 384 u_int 385 sshkey_size(const struct sshkey *k) 386 { 387 const struct sshkey_impl *impl; 388 389 if ((impl = sshkey_impl_from_key(k)) == NULL) 390 return 0; 391 if (impl->funcs->size != NULL) 392 return impl->funcs->size(k); 393 return impl->keybits; 394 } 395 396 static int 397 sshkey_type_is_valid_ca(int type) 398 { 399 const struct sshkey_impl *impl; 400 401 if ((impl = sshkey_impl_from_type(type)) == NULL) 402 return 0; 403 /* All non-certificate types may act as CAs */ 404 return !impl->cert; 405 } 406 407 int 408 sshkey_is_cert(const struct sshkey *k) 409 { 410 if (k == NULL) 411 return 0; 412 return sshkey_type_is_cert(k->type); 413 } 414 415 int 416 sshkey_is_sk(const struct sshkey *k) 417 { 418 if (k == NULL) 419 return 0; 420 switch (sshkey_type_plain(k->type)) { 421 case KEY_ECDSA_SK: 422 case KEY_ED25519_SK: 423 return 1; 424 default: 425 return 0; 426 } 427 } 428 429 /* Return the cert-less equivalent to a certified key type */ 430 int 431 sshkey_type_plain(int type) 432 { 433 switch (type) { 434 case KEY_RSA_CERT: 435 return KEY_RSA; 436 case KEY_ECDSA_CERT: 437 return KEY_ECDSA; 438 case KEY_ECDSA_SK_CERT: 439 return KEY_ECDSA_SK; 440 case KEY_ED25519_CERT: 441 return KEY_ED25519; 442 case KEY_ED25519_SK_CERT: 443 return KEY_ED25519_SK; 444 default: 445 return type; 446 } 447 } 448 449 /* Return the cert equivalent to a plain key type */ 450 static int 451 sshkey_type_certified(int type) 452 { 453 switch (type) { 454 case KEY_RSA: 455 return KEY_RSA_CERT; 456 case KEY_ECDSA: 457 return KEY_ECDSA_CERT; 458 case KEY_ECDSA_SK: 459 return KEY_ECDSA_SK_CERT; 460 case KEY_ED25519: 461 return KEY_ED25519_CERT; 462 case KEY_ED25519_SK: 463 return KEY_ED25519_SK_CERT; 464 default: 465 return -1; 466 } 467 } 468 469 #ifdef WITH_OPENSSL 470 static const EVP_MD * 471 ssh_digest_to_md(int hash_alg) 472 { 473 switch (hash_alg) { 474 case SSH_DIGEST_SHA1: 475 return EVP_sha1(); 476 case SSH_DIGEST_SHA256: 477 return EVP_sha256(); 478 case SSH_DIGEST_SHA384: 479 return EVP_sha384(); 480 case SSH_DIGEST_SHA512: 481 return EVP_sha512(); 482 } 483 return NULL; 484 } 485 486 int 487 sshkey_pkey_digest_sign(EVP_PKEY *pkey, int hash_alg, u_char **sigp, 488 size_t *lenp, const u_char *data, size_t datalen) 489 { 490 EVP_MD_CTX *ctx = NULL; 491 u_char *sig = NULL; 492 int ret; 493 size_t slen; 494 const EVP_MD *evpmd; 495 496 *sigp = NULL; 497 *lenp = 0; 498 499 slen = EVP_PKEY_size(pkey); 500 if (slen <= 0 || slen > SSHBUF_MAX_BIGNUM || 501 (evpmd = ssh_digest_to_md(hash_alg)) == NULL) 502 return SSH_ERR_INVALID_ARGUMENT; 503 504 if ((sig = malloc(slen)) == NULL) 505 return SSH_ERR_ALLOC_FAIL; 506 507 if ((ctx = EVP_MD_CTX_new()) == NULL) { 508 ret = SSH_ERR_ALLOC_FAIL; 509 goto out; 510 } 511 if (EVP_DigestSignInit(ctx, NULL, evpmd, NULL, pkey) != 1 || 512 EVP_DigestSign(ctx, sig, &slen, data, datalen) != 1) { 513 ret = SSH_ERR_LIBCRYPTO_ERROR; 514 goto out; 515 } 516 517 *sigp = sig; 518 *lenp = slen; 519 /* Now owned by the caller */ 520 sig = NULL; 521 ret = 0; 522 523 out: 524 EVP_MD_CTX_free(ctx); 525 free(sig); 526 return ret; 527 } 528 529 int 530 sshkey_pkey_digest_verify(EVP_PKEY *pkey, int hash_alg, const u_char *data, 531 size_t datalen, u_char *sigbuf, size_t siglen) 532 { 533 EVP_MD_CTX *ctx = NULL; 534 int ret = SSH_ERR_INTERNAL_ERROR; 535 const EVP_MD *evpmd; 536 537 if ((evpmd = ssh_digest_to_md(hash_alg)) == NULL) 538 return SSH_ERR_INVALID_ARGUMENT; 539 if ((ctx = EVP_MD_CTX_new()) == NULL) 540 return SSH_ERR_ALLOC_FAIL; 541 if (EVP_DigestVerifyInit(ctx, NULL, evpmd, NULL, pkey) != 1) { 542 ret = SSH_ERR_LIBCRYPTO_ERROR; 543 goto out; 544 } 545 switch (EVP_DigestVerify(ctx, sigbuf, siglen, data, datalen)) { 546 case 1: 547 ret = 0; 548 break; 549 case 0: 550 ret = SSH_ERR_SIGNATURE_INVALID; 551 break; 552 default: 553 ret = SSH_ERR_LIBCRYPTO_ERROR; 554 break; 555 } 556 557 out: 558 EVP_MD_CTX_free(ctx); 559 return ret; 560 } 561 562 /* XXX: these are really begging for a table-driven approach */ 563 int 564 sshkey_curve_name_to_nid(const char *name) 565 { 566 if (strcmp(name, "nistp256") == 0) 567 return NID_X9_62_prime256v1; 568 else if (strcmp(name, "nistp384") == 0) 569 return NID_secp384r1; 570 # ifdef OPENSSL_HAS_NISTP521 571 else if (strcmp(name, "nistp521") == 0) 572 return NID_secp521r1; 573 # endif /* OPENSSL_HAS_NISTP521 */ 574 else 575 return -1; 576 } 577 578 u_int 579 sshkey_curve_nid_to_bits(int nid) 580 { 581 switch (nid) { 582 case NID_X9_62_prime256v1: 583 return 256; 584 case NID_secp384r1: 585 return 384; 586 # ifdef OPENSSL_HAS_NISTP521 587 case NID_secp521r1: 588 return 521; 589 # endif /* OPENSSL_HAS_NISTP521 */ 590 default: 591 return 0; 592 } 593 } 594 595 int 596 sshkey_ecdsa_bits_to_nid(int bits) 597 { 598 switch (bits) { 599 case 256: 600 return NID_X9_62_prime256v1; 601 case 384: 602 return NID_secp384r1; 603 # ifdef OPENSSL_HAS_NISTP521 604 case 521: 605 return NID_secp521r1; 606 # endif /* OPENSSL_HAS_NISTP521 */ 607 default: 608 return -1; 609 } 610 } 611 612 const char * 613 sshkey_curve_nid_to_name(int nid) 614 { 615 switch (nid) { 616 case NID_X9_62_prime256v1: 617 return "nistp256"; 618 case NID_secp384r1: 619 return "nistp384"; 620 # ifdef OPENSSL_HAS_NISTP521 621 case NID_secp521r1: 622 return "nistp521"; 623 # endif /* OPENSSL_HAS_NISTP521 */ 624 default: 625 return NULL; 626 } 627 } 628 629 int 630 sshkey_ec_nid_to_hash_alg(int nid) 631 { 632 int kbits = sshkey_curve_nid_to_bits(nid); 633 634 if (kbits <= 0) 635 return -1; 636 637 /* RFC5656 section 6.2.1 */ 638 if (kbits <= 256) 639 return SSH_DIGEST_SHA256; 640 else if (kbits <= 384) 641 return SSH_DIGEST_SHA384; 642 else 643 return SSH_DIGEST_SHA512; 644 } 645 #endif /* WITH_OPENSSL */ 646 647 static void 648 cert_free(struct sshkey_cert *cert) 649 { 650 u_int i; 651 652 if (cert == NULL) 653 return; 654 sshbuf_free(cert->certblob); 655 sshbuf_free(cert->critical); 656 sshbuf_free(cert->extensions); 657 free(cert->key_id); 658 for (i = 0; i < cert->nprincipals; i++) 659 free(cert->principals[i]); 660 free(cert->principals); 661 sshkey_free(cert->signature_key); 662 free(cert->signature_type); 663 freezero(cert, sizeof(*cert)); 664 } 665 666 static struct sshkey_cert * 667 cert_new(void) 668 { 669 struct sshkey_cert *cert; 670 671 if ((cert = calloc(1, sizeof(*cert))) == NULL) 672 return NULL; 673 if ((cert->certblob = sshbuf_new()) == NULL || 674 (cert->critical = sshbuf_new()) == NULL || 675 (cert->extensions = sshbuf_new()) == NULL) { 676 cert_free(cert); 677 return NULL; 678 } 679 cert->key_id = NULL; 680 cert->principals = NULL; 681 cert->signature_key = NULL; 682 cert->signature_type = NULL; 683 return cert; 684 } 685 686 struct sshkey * 687 sshkey_new(int type) 688 { 689 struct sshkey *k; 690 const struct sshkey_impl *impl = NULL; 691 692 if (type != KEY_UNSPEC && 693 (impl = sshkey_impl_from_type(type)) == NULL) 694 return NULL; 695 696 /* All non-certificate types may act as CAs */ 697 if ((k = calloc(1, sizeof(*k))) == NULL) 698 return NULL; 699 k->type = type; 700 k->ecdsa_nid = -1; 701 if (impl != NULL && impl->funcs->alloc != NULL) { 702 if (impl->funcs->alloc(k) != 0) { 703 free(k); 704 return NULL; 705 } 706 } 707 if (sshkey_is_cert(k)) { 708 if ((k->cert = cert_new()) == NULL) { 709 sshkey_free(k); 710 return NULL; 711 } 712 } 713 714 return k; 715 } 716 717 /* Frees common FIDO fields */ 718 void 719 sshkey_sk_cleanup(struct sshkey *k) 720 { 721 free(k->sk_application); 722 sshbuf_free(k->sk_key_handle); 723 sshbuf_free(k->sk_reserved); 724 k->sk_application = NULL; 725 k->sk_key_handle = k->sk_reserved = NULL; 726 } 727 728 #if defined(MAP_CONCEAL) 729 # define PREKEY_MMAP_FLAG MAP_CONCEAL 730 #elif defined(MAP_NOCORE) 731 # define PREKEY_MMAP_FLAG MAP_NOCORE 732 #else 733 # define PREKEY_MMAP_FLAG 0 734 #endif 735 736 static int 737 sshkey_prekey_alloc(u_char **prekeyp, size_t len) 738 { 739 #if defined(HAVE_MMAP) && defined(MAP_ANON) && defined(MAP_PRIVATE) 740 u_char *prekey; 741 742 *prekeyp = NULL; 743 if ((prekey = mmap(NULL, len, PROT_READ|PROT_WRITE, 744 MAP_ANON|MAP_PRIVATE|PREKEY_MMAP_FLAG, -1, 0)) == MAP_FAILED) 745 return SSH_ERR_SYSTEM_ERROR; 746 #if defined(MADV_DONTDUMP) && !defined(MAP_CONCEAL) && !defined(MAP_NOCORE) 747 (void)madvise(prekey, len, MADV_DONTDUMP); 748 #endif 749 *prekeyp = prekey; 750 #else 751 *prekeyp = calloc(1, len); 752 #endif /* HAVE_MMAP et al */ 753 return 0; 754 } 755 756 static void 757 sshkey_prekey_free(void *prekey, size_t len) 758 { 759 #if defined(HAVE_MMAP) && defined(MAP_ANON) && defined(MAP_PRIVATE) 760 if (prekey == NULL) 761 return; 762 munmap(prekey, len); 763 #else 764 free(prekey); 765 #endif /* HAVE_MMAP et al */ 766 } 767 768 static void 769 sshkey_free_contents(struct sshkey *k) 770 { 771 const struct sshkey_impl *impl; 772 773 if (k == NULL) 774 return; 775 if ((k->flags & SSHKEY_FLAG_EXT) != 0) 776 pkcs11_key_free(k); 777 if ((impl = sshkey_impl_from_type(k->type)) != NULL && 778 impl->funcs->cleanup != NULL) 779 impl->funcs->cleanup(k); 780 if (sshkey_is_cert(k)) 781 cert_free(k->cert); 782 freezero(k->shielded_private, k->shielded_len); 783 sshkey_prekey_free(k->shield_prekey, k->shield_prekey_len); 784 } 785 786 void 787 sshkey_free(struct sshkey *k) 788 { 789 sshkey_free_contents(k); 790 freezero(k, sizeof(*k)); 791 } 792 793 static int 794 cert_compare(struct sshkey_cert *a, struct sshkey_cert *b) 795 { 796 if (a == NULL && b == NULL) 797 return 1; 798 if (a == NULL || b == NULL) 799 return 0; 800 if (sshbuf_len(a->certblob) != sshbuf_len(b->certblob)) 801 return 0; 802 if (timingsafe_bcmp(sshbuf_ptr(a->certblob), sshbuf_ptr(b->certblob), 803 sshbuf_len(a->certblob)) != 0) 804 return 0; 805 return 1; 806 } 807 808 /* Compares FIDO-specific pubkey fields only */ 809 int 810 sshkey_sk_fields_equal(const struct sshkey *a, const struct sshkey *b) 811 { 812 if (a->sk_application == NULL || b->sk_application == NULL) 813 return 0; 814 if (strcmp(a->sk_application, b->sk_application) != 0) 815 return 0; 816 return 1; 817 } 818 819 /* 820 * Compare public portions of key only, allowing comparisons between 821 * certificates and plain keys too. 822 */ 823 int 824 sshkey_equal_public(const struct sshkey *a, const struct sshkey *b) 825 { 826 const struct sshkey_impl *impl; 827 828 if (a == NULL || b == NULL || 829 sshkey_type_plain(a->type) != sshkey_type_plain(b->type)) 830 return 0; 831 if ((impl = sshkey_impl_from_type(a->type)) == NULL) 832 return 0; 833 return impl->funcs->equal(a, b); 834 } 835 836 int 837 sshkey_equal(const struct sshkey *a, const struct sshkey *b) 838 { 839 if (a == NULL || b == NULL || a->type != b->type) 840 return 0; 841 if (sshkey_is_cert(a)) { 842 if (!cert_compare(a->cert, b->cert)) 843 return 0; 844 } 845 return sshkey_equal_public(a, b); 846 } 847 848 849 /* Serialise common FIDO key parts */ 850 int 851 sshkey_serialize_sk(const struct sshkey *key, struct sshbuf *b) 852 { 853 int r; 854 855 if ((r = sshbuf_put_cstring(b, key->sk_application)) != 0) 856 return r; 857 858 return 0; 859 } 860 861 static int 862 to_blob_buf(const struct sshkey *key, struct sshbuf *b, int force_plain, 863 enum sshkey_serialize_rep opts) 864 { 865 int type, ret = SSH_ERR_INTERNAL_ERROR; 866 const char *typename; 867 const struct sshkey_impl *impl; 868 869 if (key == NULL) 870 return SSH_ERR_INVALID_ARGUMENT; 871 872 type = force_plain ? sshkey_type_plain(key->type) : key->type; 873 874 if (sshkey_type_is_cert(type)) { 875 if (key->cert == NULL) 876 return SSH_ERR_EXPECTED_CERT; 877 if (sshbuf_len(key->cert->certblob) == 0) 878 return SSH_ERR_KEY_LACKS_CERTBLOB; 879 /* Use the existing blob */ 880 if ((ret = sshbuf_putb(b, key->cert->certblob)) != 0) 881 return ret; 882 return 0; 883 } 884 if ((impl = sshkey_impl_from_type(type)) == NULL) 885 return SSH_ERR_KEY_TYPE_UNKNOWN; 886 887 typename = sshkey_ssh_name_from_type_nid(type, key->ecdsa_nid); 888 if ((ret = sshbuf_put_cstring(b, typename)) != 0) 889 return ret; 890 return impl->funcs->serialize_public(key, b, opts); 891 } 892 893 int 894 sshkey_putb(const struct sshkey *key, struct sshbuf *b) 895 { 896 return to_blob_buf(key, b, 0, SSHKEY_SERIALIZE_DEFAULT); 897 } 898 899 static int 900 sshkey_puts_opts_internal(const struct sshkey *key, struct sshbuf *b, 901 enum sshkey_serialize_rep opts, int force_plain) 902 { 903 struct sshbuf *tmp; 904 int r; 905 906 if ((tmp = sshbuf_new()) == NULL) 907 return SSH_ERR_ALLOC_FAIL; 908 r = to_blob_buf(key, tmp, force_plain, opts); 909 if (r == 0) 910 r = sshbuf_put_stringb(b, tmp); 911 sshbuf_free(tmp); 912 return r; 913 } 914 915 int 916 sshkey_puts(const struct sshkey *key, struct sshbuf *b) 917 { 918 return sshkey_puts_opts_internal(key, b, SSHKEY_SERIALIZE_DEFAULT, 0); 919 } 920 921 int 922 sshkey_putb_plain(const struct sshkey *key, struct sshbuf *b) 923 { 924 return to_blob_buf(key, b, 1, SSHKEY_SERIALIZE_DEFAULT); 925 } 926 927 int 928 sshkey_puts_plain(const struct sshkey *key, struct sshbuf *b) 929 { 930 return sshkey_puts_opts_internal(key, b, SSHKEY_SERIALIZE_DEFAULT, 1); 931 } 932 933 static int 934 to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp, int force_plain, 935 enum sshkey_serialize_rep opts) 936 { 937 int ret = SSH_ERR_INTERNAL_ERROR; 938 size_t len; 939 struct sshbuf *b = NULL; 940 941 if (lenp != NULL) 942 *lenp = 0; 943 if (blobp != NULL) 944 *blobp = NULL; 945 if ((b = sshbuf_new()) == NULL) 946 return SSH_ERR_ALLOC_FAIL; 947 if ((ret = to_blob_buf(key, b, force_plain, opts)) != 0) 948 goto out; 949 len = sshbuf_len(b); 950 if (lenp != NULL) 951 *lenp = len; 952 if (blobp != NULL) { 953 if ((*blobp = malloc(len)) == NULL) { 954 ret = SSH_ERR_ALLOC_FAIL; 955 goto out; 956 } 957 memcpy(*blobp, sshbuf_ptr(b), len); 958 } 959 ret = 0; 960 out: 961 sshbuf_free(b); 962 return ret; 963 } 964 965 int 966 sshkey_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp) 967 { 968 return to_blob(key, blobp, lenp, 0, SSHKEY_SERIALIZE_DEFAULT); 969 } 970 971 int 972 sshkey_plain_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp) 973 { 974 return to_blob(key, blobp, lenp, 1, SSHKEY_SERIALIZE_DEFAULT); 975 } 976 977 int 978 sshkey_fingerprint_raw(const struct sshkey *k, int dgst_alg, 979 u_char **retp, size_t *lenp) 980 { 981 u_char *blob = NULL, *ret = NULL; 982 size_t blob_len = 0; 983 int r = SSH_ERR_INTERNAL_ERROR; 984 985 if (retp != NULL) 986 *retp = NULL; 987 if (lenp != NULL) 988 *lenp = 0; 989 if (ssh_digest_bytes(dgst_alg) == 0) { 990 r = SSH_ERR_INVALID_ARGUMENT; 991 goto out; 992 } 993 if ((r = to_blob(k, &blob, &blob_len, 1, SSHKEY_SERIALIZE_DEFAULT)) 994 != 0) 995 goto out; 996 if ((ret = calloc(1, SSH_DIGEST_MAX_LENGTH)) == NULL) { 997 r = SSH_ERR_ALLOC_FAIL; 998 goto out; 999 } 1000 if ((r = ssh_digest_memory(dgst_alg, blob, blob_len, 1001 ret, SSH_DIGEST_MAX_LENGTH)) != 0) 1002 goto out; 1003 /* success */ 1004 if (retp != NULL) { 1005 *retp = ret; 1006 ret = NULL; 1007 } 1008 if (lenp != NULL) 1009 *lenp = ssh_digest_bytes(dgst_alg); 1010 r = 0; 1011 out: 1012 free(ret); 1013 if (blob != NULL) 1014 freezero(blob, blob_len); 1015 return r; 1016 } 1017 1018 static char * 1019 fingerprint_b64(const char *alg, u_char *dgst_raw, size_t dgst_raw_len) 1020 { 1021 char *ret; 1022 size_t plen = strlen(alg) + 1; 1023 size_t rlen = ((dgst_raw_len + 2) / 3) * 4 + plen + 1; 1024 1025 if (dgst_raw_len > 65536 || (ret = calloc(1, rlen)) == NULL) 1026 return NULL; 1027 strlcpy(ret, alg, rlen); 1028 strlcat(ret, ":", rlen); 1029 if (dgst_raw_len == 0) 1030 return ret; 1031 if (b64_ntop(dgst_raw, dgst_raw_len, ret + plen, rlen - plen) == -1) { 1032 freezero(ret, rlen); 1033 return NULL; 1034 } 1035 /* Trim padding characters from end */ 1036 ret[strcspn(ret, "=")] = '\0'; 1037 return ret; 1038 } 1039 1040 static char * 1041 fingerprint_hex(const char *alg, u_char *dgst_raw, size_t dgst_raw_len) 1042 { 1043 char *retval, hex[5]; 1044 size_t i, rlen = dgst_raw_len * 3 + strlen(alg) + 2; 1045 1046 if (dgst_raw_len > 65536 || (retval = calloc(1, rlen)) == NULL) 1047 return NULL; 1048 strlcpy(retval, alg, rlen); 1049 strlcat(retval, ":", rlen); 1050 for (i = 0; i < dgst_raw_len; i++) { 1051 snprintf(hex, sizeof(hex), "%s%02x", 1052 i > 0 ? ":" : "", dgst_raw[i]); 1053 strlcat(retval, hex, rlen); 1054 } 1055 return retval; 1056 } 1057 1058 static char * 1059 fingerprint_bubblebabble(u_char *dgst_raw, size_t dgst_raw_len) 1060 { 1061 char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' }; 1062 char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm', 1063 'n', 'p', 'r', 's', 't', 'v', 'z', 'x' }; 1064 u_int i, j = 0, rounds, seed = 1; 1065 char *retval; 1066 1067 rounds = (dgst_raw_len / 2) + 1; 1068 if ((retval = calloc(rounds, 6)) == NULL) 1069 return NULL; 1070 retval[j++] = 'x'; 1071 for (i = 0; i < rounds; i++) { 1072 u_int idx0, idx1, idx2, idx3, idx4; 1073 if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) { 1074 idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) + 1075 seed) % 6; 1076 idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15; 1077 idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) + 1078 (seed / 6)) % 6; 1079 retval[j++] = vowels[idx0]; 1080 retval[j++] = consonants[idx1]; 1081 retval[j++] = vowels[idx2]; 1082 if ((i + 1) < rounds) { 1083 idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15; 1084 idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15; 1085 retval[j++] = consonants[idx3]; 1086 retval[j++] = '-'; 1087 retval[j++] = consonants[idx4]; 1088 seed = ((seed * 5) + 1089 ((((u_int)(dgst_raw[2 * i])) * 7) + 1090 ((u_int)(dgst_raw[(2 * i) + 1])))) % 36; 1091 } 1092 } else { 1093 idx0 = seed % 6; 1094 idx1 = 16; 1095 idx2 = seed / 6; 1096 retval[j++] = vowels[idx0]; 1097 retval[j++] = consonants[idx1]; 1098 retval[j++] = vowels[idx2]; 1099 } 1100 } 1101 retval[j++] = 'x'; 1102 retval[j++] = '\0'; 1103 return retval; 1104 } 1105 1106 /* 1107 * Draw an ASCII-Art representing the fingerprint so human brain can 1108 * profit from its built-in pattern recognition ability. 1109 * This technique is called "random art" and can be found in some 1110 * scientific publications like this original paper: 1111 * 1112 * "Hash Visualization: a New Technique to improve Real-World Security", 1113 * Perrig A. and Song D., 1999, International Workshop on Cryptographic 1114 * Techniques and E-Commerce (CrypTEC '99) 1115 * sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf 1116 * 1117 * The subject came up in a talk by Dan Kaminsky, too. 1118 * 1119 * If you see the picture is different, the key is different. 1120 * If the picture looks the same, you still know nothing. 1121 * 1122 * The algorithm used here is a worm crawling over a discrete plane, 1123 * leaving a trace (augmenting the field) everywhere it goes. 1124 * Movement is taken from dgst_raw 2bit-wise. Bumping into walls 1125 * makes the respective movement vector be ignored for this turn. 1126 * Graphs are not unambiguous, because circles in graphs can be 1127 * walked in either direction. 1128 */ 1129 1130 /* 1131 * Field sizes for the random art. Have to be odd, so the starting point 1132 * can be in the exact middle of the picture, and FLDBASE should be >=8 . 1133 * Else pictures would be too dense, and drawing the frame would 1134 * fail, too, because the key type would not fit in anymore. 1135 */ 1136 #define FLDBASE 8 1137 #define FLDSIZE_Y (FLDBASE + 1) 1138 #define FLDSIZE_X (FLDBASE * 2 + 1) 1139 static char * 1140 fingerprint_randomart(const char *alg, u_char *dgst_raw, size_t dgst_raw_len, 1141 const struct sshkey *k) 1142 { 1143 /* 1144 * Chars to be used after each other every time the worm 1145 * intersects with itself. Matter of taste. 1146 */ 1147 char *augmentation_string = " .o+=*BOX@%&#/^SE"; 1148 char *retval, *p, title[FLDSIZE_X], hash[FLDSIZE_X]; 1149 u_char field[FLDSIZE_X][FLDSIZE_Y]; 1150 size_t i, tlen, hlen; 1151 u_int b; 1152 int x, y, r; 1153 size_t len = strlen(augmentation_string) - 1; 1154 1155 if ((retval = calloc((FLDSIZE_X + 3), (FLDSIZE_Y + 2))) == NULL) 1156 return NULL; 1157 1158 /* initialize field */ 1159 memset(field, 0, FLDSIZE_X * FLDSIZE_Y * sizeof(char)); 1160 x = FLDSIZE_X / 2; 1161 y = FLDSIZE_Y / 2; 1162 1163 /* process raw key */ 1164 for (i = 0; i < dgst_raw_len; i++) { 1165 int input; 1166 /* each byte conveys four 2-bit move commands */ 1167 input = dgst_raw[i]; 1168 for (b = 0; b < 4; b++) { 1169 /* evaluate 2 bit, rest is shifted later */ 1170 x += (input & 0x1) ? 1 : -1; 1171 y += (input & 0x2) ? 1 : -1; 1172 1173 /* assure we are still in bounds */ 1174 x = MAXIMUM(x, 0); 1175 y = MAXIMUM(y, 0); 1176 x = MINIMUM(x, FLDSIZE_X - 1); 1177 y = MINIMUM(y, FLDSIZE_Y - 1); 1178 1179 /* augment the field */ 1180 if (field[x][y] < len - 2) 1181 field[x][y]++; 1182 input = input >> 2; 1183 } 1184 } 1185 1186 /* mark starting point and end point*/ 1187 field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = len - 1; 1188 field[x][y] = len; 1189 1190 /* assemble title */ 1191 r = snprintf(title, sizeof(title), "[%s %u]", 1192 sshkey_type(k), sshkey_size(k)); 1193 /* If [type size] won't fit, then try [type]; fits "[ED25519-CERT]" */ 1194 if (r < 0 || r > (int)sizeof(title)) 1195 r = snprintf(title, sizeof(title), "[%s]", sshkey_type(k)); 1196 tlen = (r <= 0) ? 0 : strlen(title); 1197 1198 /* assemble hash ID. */ 1199 r = snprintf(hash, sizeof(hash), "[%s]", alg); 1200 hlen = (r <= 0) ? 0 : strlen(hash); 1201 1202 /* output upper border */ 1203 p = retval; 1204 *p++ = '+'; 1205 for (i = 0; i < (FLDSIZE_X - tlen) / 2; i++) 1206 *p++ = '-'; 1207 memcpy(p, title, tlen); 1208 p += tlen; 1209 for (i += tlen; i < FLDSIZE_X; i++) 1210 *p++ = '-'; 1211 *p++ = '+'; 1212 *p++ = '\n'; 1213 1214 /* output content */ 1215 for (y = 0; y < FLDSIZE_Y; y++) { 1216 *p++ = '|'; 1217 for (x = 0; x < FLDSIZE_X; x++) 1218 *p++ = augmentation_string[MINIMUM(field[x][y], len)]; 1219 *p++ = '|'; 1220 *p++ = '\n'; 1221 } 1222 1223 /* output lower border */ 1224 *p++ = '+'; 1225 for (i = 0; i < (FLDSIZE_X - hlen) / 2; i++) 1226 *p++ = '-'; 1227 memcpy(p, hash, hlen); 1228 p += hlen; 1229 for (i += hlen; i < FLDSIZE_X; i++) 1230 *p++ = '-'; 1231 *p++ = '+'; 1232 1233 return retval; 1234 } 1235 1236 char * 1237 sshkey_fingerprint(const struct sshkey *k, int dgst_alg, 1238 enum sshkey_fp_rep dgst_rep) 1239 { 1240 char *retval = NULL; 1241 u_char *dgst_raw; 1242 size_t dgst_raw_len; 1243 1244 if (sshkey_fingerprint_raw(k, dgst_alg, &dgst_raw, &dgst_raw_len) != 0) 1245 return NULL; 1246 switch (dgst_rep) { 1247 case SSH_FP_DEFAULT: 1248 if (dgst_alg == SSH_DIGEST_MD5) { 1249 retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg), 1250 dgst_raw, dgst_raw_len); 1251 } else { 1252 retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg), 1253 dgst_raw, dgst_raw_len); 1254 } 1255 break; 1256 case SSH_FP_HEX: 1257 retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg), 1258 dgst_raw, dgst_raw_len); 1259 break; 1260 case SSH_FP_BASE64: 1261 retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg), 1262 dgst_raw, dgst_raw_len); 1263 break; 1264 case SSH_FP_BUBBLEBABBLE: 1265 retval = fingerprint_bubblebabble(dgst_raw, dgst_raw_len); 1266 break; 1267 case SSH_FP_RANDOMART: 1268 retval = fingerprint_randomart(ssh_digest_alg_name(dgst_alg), 1269 dgst_raw, dgst_raw_len, k); 1270 break; 1271 default: 1272 freezero(dgst_raw, dgst_raw_len); 1273 return NULL; 1274 } 1275 freezero(dgst_raw, dgst_raw_len); 1276 return retval; 1277 } 1278 1279 static int 1280 peek_type_nid(const char *s, size_t l, int *nid) 1281 { 1282 const struct sshkey_impl *impl; 1283 int i; 1284 1285 for (i = 0; keyimpls[i] != NULL; i++) { 1286 impl = keyimpls[i]; 1287 if (impl->name == NULL || strlen(impl->name) != l) 1288 continue; 1289 if (memcmp(s, impl->name, l) == 0) { 1290 *nid = -1; 1291 if (key_type_is_ecdsa_variant(impl->type)) 1292 *nid = impl->nid; 1293 return impl->type; 1294 } 1295 } 1296 return KEY_UNSPEC; 1297 } 1298 1299 /* XXX this can now be made const char * */ 1300 int 1301 sshkey_read(struct sshkey *ret, char **cpp) 1302 { 1303 struct sshkey *k; 1304 char *cp, *blobcopy; 1305 size_t space; 1306 int r, type, curve_nid = -1; 1307 struct sshbuf *blob; 1308 1309 if (ret == NULL) 1310 return SSH_ERR_INVALID_ARGUMENT; 1311 if (ret->type != KEY_UNSPEC && sshkey_impl_from_type(ret->type) == NULL) 1312 return SSH_ERR_INVALID_ARGUMENT; 1313 1314 /* Decode type */ 1315 cp = *cpp; 1316 space = strcspn(cp, " \t"); 1317 if (space == strlen(cp)) 1318 return SSH_ERR_INVALID_FORMAT; 1319 if ((type = peek_type_nid(cp, space, &curve_nid)) == KEY_UNSPEC) 1320 return SSH_ERR_INVALID_FORMAT; 1321 1322 /* skip whitespace */ 1323 for (cp += space; *cp == ' ' || *cp == '\t'; cp++) 1324 ; 1325 if (*cp == '\0') 1326 return SSH_ERR_INVALID_FORMAT; 1327 if (ret->type != KEY_UNSPEC && ret->type != type) 1328 return SSH_ERR_KEY_TYPE_MISMATCH; 1329 if ((blob = sshbuf_new()) == NULL) 1330 return SSH_ERR_ALLOC_FAIL; 1331 1332 /* find end of keyblob and decode */ 1333 space = strcspn(cp, " \t"); 1334 if ((blobcopy = strndup(cp, space)) == NULL) { 1335 sshbuf_free(blob); 1336 return SSH_ERR_ALLOC_FAIL; 1337 } 1338 if ((r = sshbuf_b64tod(blob, blobcopy)) != 0) { 1339 free(blobcopy); 1340 sshbuf_free(blob); 1341 return r; 1342 } 1343 free(blobcopy); 1344 if ((r = sshkey_fromb(blob, &k)) != 0) { 1345 sshbuf_free(blob); 1346 return r; 1347 } 1348 sshbuf_free(blob); 1349 1350 /* skip whitespace and leave cp at start of comment */ 1351 for (cp += space; *cp == ' ' || *cp == '\t'; cp++) 1352 ; 1353 1354 /* ensure type of blob matches type at start of line */ 1355 if (k->type != type) { 1356 sshkey_free(k); 1357 return SSH_ERR_KEY_TYPE_MISMATCH; 1358 } 1359 if (key_type_is_ecdsa_variant(type) && curve_nid != k->ecdsa_nid) { 1360 sshkey_free(k); 1361 return SSH_ERR_EC_CURVE_MISMATCH; 1362 } 1363 1364 /* Fill in ret from parsed key */ 1365 sshkey_free_contents(ret); 1366 *ret = *k; 1367 freezero(k, sizeof(*k)); 1368 1369 /* success */ 1370 *cpp = cp; 1371 return 0; 1372 } 1373 1374 int 1375 sshkey_to_base64(const struct sshkey *key, char **b64p) 1376 { 1377 int r = SSH_ERR_INTERNAL_ERROR; 1378 struct sshbuf *b = NULL; 1379 char *uu = NULL; 1380 1381 if (b64p != NULL) 1382 *b64p = NULL; 1383 if ((b = sshbuf_new()) == NULL) 1384 return SSH_ERR_ALLOC_FAIL; 1385 if ((r = sshkey_putb(key, b)) != 0) 1386 goto out; 1387 if ((uu = sshbuf_dtob64_string(b, 0)) == NULL) { 1388 r = SSH_ERR_ALLOC_FAIL; 1389 goto out; 1390 } 1391 /* Success */ 1392 if (b64p != NULL) { 1393 *b64p = uu; 1394 uu = NULL; 1395 } 1396 r = 0; 1397 out: 1398 sshbuf_free(b); 1399 free(uu); 1400 return r; 1401 } 1402 1403 int 1404 sshkey_format_text(const struct sshkey *key, struct sshbuf *b) 1405 { 1406 int r = SSH_ERR_INTERNAL_ERROR; 1407 char *uu = NULL; 1408 1409 if ((r = sshkey_to_base64(key, &uu)) != 0) 1410 goto out; 1411 if ((r = sshbuf_putf(b, "%s %s", 1412 sshkey_ssh_name(key), uu)) != 0) 1413 goto out; 1414 r = 0; 1415 out: 1416 free(uu); 1417 return r; 1418 } 1419 1420 int 1421 sshkey_write(const struct sshkey *key, FILE *f) 1422 { 1423 struct sshbuf *b = NULL; 1424 int r = SSH_ERR_INTERNAL_ERROR; 1425 1426 if ((b = sshbuf_new()) == NULL) 1427 return SSH_ERR_ALLOC_FAIL; 1428 if ((r = sshkey_format_text(key, b)) != 0) 1429 goto out; 1430 if (fwrite(sshbuf_ptr(b), sshbuf_len(b), 1, f) != 1) { 1431 if (feof(f)) 1432 errno = EPIPE; 1433 r = SSH_ERR_SYSTEM_ERROR; 1434 goto out; 1435 } 1436 /* Success */ 1437 r = 0; 1438 out: 1439 sshbuf_free(b); 1440 return r; 1441 } 1442 1443 const char * 1444 sshkey_cert_type(const struct sshkey *k) 1445 { 1446 switch (k->cert->type) { 1447 case SSH2_CERT_TYPE_USER: 1448 return "user"; 1449 case SSH2_CERT_TYPE_HOST: 1450 return "host"; 1451 default: 1452 return "unknown"; 1453 } 1454 } 1455 1456 int 1457 sshkey_check_rsa_length(const struct sshkey *k, int min_size) 1458 { 1459 #ifdef WITH_OPENSSL 1460 int nbits; 1461 1462 if (k == NULL || k->pkey == NULL || 1463 (k->type != KEY_RSA && k->type != KEY_RSA_CERT)) 1464 return 0; 1465 nbits = EVP_PKEY_bits(k->pkey); 1466 if (nbits < SSH_RSA_MINIMUM_MODULUS_SIZE || 1467 (min_size > 0 && nbits < min_size)) 1468 return SSH_ERR_KEY_LENGTH; 1469 #endif /* WITH_OPENSSL */ 1470 return 0; 1471 } 1472 1473 #if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) 1474 int 1475 sshkey_ecdsa_key_to_nid(const EC_KEY *k) 1476 { 1477 const EC_GROUP *g; 1478 int nid; 1479 1480 if (k == NULL || (g = EC_KEY_get0_group(k)) == NULL) 1481 return -1; 1482 if ((nid = EC_GROUP_get_curve_name(g)) <= 0) 1483 return -1; 1484 return nid; 1485 } 1486 1487 int 1488 sshkey_ecdsa_pkey_to_nid(EVP_PKEY *pkey) 1489 { 1490 return sshkey_ecdsa_key_to_nid(EVP_PKEY_get0_EC_KEY(pkey)); 1491 } 1492 #endif /* defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) */ 1493 1494 int 1495 sshkey_generate(int type, u_int bits, struct sshkey **keyp) 1496 { 1497 struct sshkey *k; 1498 int ret = SSH_ERR_INTERNAL_ERROR; 1499 const struct sshkey_impl *impl; 1500 1501 if (keyp == NULL || sshkey_type_is_cert(type)) 1502 return SSH_ERR_INVALID_ARGUMENT; 1503 *keyp = NULL; 1504 if ((impl = sshkey_impl_from_type(type)) == NULL) 1505 return SSH_ERR_KEY_TYPE_UNKNOWN; 1506 if (impl->funcs->generate == NULL) 1507 return SSH_ERR_FEATURE_UNSUPPORTED; 1508 if ((k = sshkey_new(KEY_UNSPEC)) == NULL) 1509 return SSH_ERR_ALLOC_FAIL; 1510 k->type = type; 1511 if ((ret = impl->funcs->generate(k, bits)) != 0) { 1512 sshkey_free(k); 1513 return ret; 1514 } 1515 /* success */ 1516 *keyp = k; 1517 return 0; 1518 } 1519 1520 int 1521 sshkey_cert_copy(const struct sshkey *from_key, struct sshkey *to_key) 1522 { 1523 u_int i; 1524 const struct sshkey_cert *from; 1525 struct sshkey_cert *to; 1526 int r = SSH_ERR_INTERNAL_ERROR; 1527 1528 if (to_key == NULL || (from = from_key->cert) == NULL) 1529 return SSH_ERR_INVALID_ARGUMENT; 1530 1531 if ((to = cert_new()) == NULL) 1532 return SSH_ERR_ALLOC_FAIL; 1533 1534 if ((r = sshbuf_putb(to->certblob, from->certblob)) != 0 || 1535 (r = sshbuf_putb(to->critical, from->critical)) != 0 || 1536 (r = sshbuf_putb(to->extensions, from->extensions)) != 0) 1537 goto out; 1538 1539 to->serial = from->serial; 1540 to->type = from->type; 1541 if (from->key_id == NULL) 1542 to->key_id = NULL; 1543 else if ((to->key_id = strdup(from->key_id)) == NULL) { 1544 r = SSH_ERR_ALLOC_FAIL; 1545 goto out; 1546 } 1547 to->valid_after = from->valid_after; 1548 to->valid_before = from->valid_before; 1549 if (from->signature_key == NULL) 1550 to->signature_key = NULL; 1551 else if ((r = sshkey_from_private(from->signature_key, 1552 &to->signature_key)) != 0) 1553 goto out; 1554 if (from->signature_type != NULL && 1555 (to->signature_type = strdup(from->signature_type)) == NULL) { 1556 r = SSH_ERR_ALLOC_FAIL; 1557 goto out; 1558 } 1559 if (from->nprincipals > SSHKEY_CERT_MAX_PRINCIPALS) { 1560 r = SSH_ERR_INVALID_ARGUMENT; 1561 goto out; 1562 } 1563 if (from->nprincipals > 0) { 1564 if ((to->principals = calloc(from->nprincipals, 1565 sizeof(*to->principals))) == NULL) { 1566 r = SSH_ERR_ALLOC_FAIL; 1567 goto out; 1568 } 1569 for (i = 0; i < from->nprincipals; i++) { 1570 to->principals[i] = strdup(from->principals[i]); 1571 if (to->principals[i] == NULL) { 1572 to->nprincipals = i; 1573 r = SSH_ERR_ALLOC_FAIL; 1574 goto out; 1575 } 1576 } 1577 } 1578 to->nprincipals = from->nprincipals; 1579 1580 /* success */ 1581 cert_free(to_key->cert); 1582 to_key->cert = to; 1583 to = NULL; 1584 r = 0; 1585 out: 1586 cert_free(to); 1587 return r; 1588 } 1589 1590 int 1591 sshkey_copy_public_sk(const struct sshkey *from, struct sshkey *to) 1592 { 1593 /* Append security-key application string */ 1594 if ((to->sk_application = strdup(from->sk_application)) == NULL) 1595 return SSH_ERR_ALLOC_FAIL; 1596 return 0; 1597 } 1598 1599 int 1600 sshkey_from_private(const struct sshkey *k, struct sshkey **pkp) 1601 { 1602 struct sshkey *n = NULL; 1603 int r = SSH_ERR_INTERNAL_ERROR; 1604 const struct sshkey_impl *impl; 1605 1606 *pkp = NULL; 1607 if ((impl = sshkey_impl_from_key(k)) == NULL) 1608 return SSH_ERR_KEY_TYPE_UNKNOWN; 1609 if ((n = sshkey_new(k->type)) == NULL) { 1610 r = SSH_ERR_ALLOC_FAIL; 1611 goto out; 1612 } 1613 if ((r = impl->funcs->copy_public(k, n)) != 0) 1614 goto out; 1615 if (sshkey_is_cert(k) && (r = sshkey_cert_copy(k, n)) != 0) 1616 goto out; 1617 /* success */ 1618 *pkp = n; 1619 n = NULL; 1620 r = 0; 1621 out: 1622 sshkey_free(n); 1623 return r; 1624 } 1625 1626 int 1627 sshkey_is_shielded(struct sshkey *k) 1628 { 1629 return k != NULL && k->shielded_private != NULL; 1630 } 1631 1632 int 1633 sshkey_shield_private(struct sshkey *k) 1634 { 1635 struct sshbuf *prvbuf = NULL; 1636 u_char *prekey = NULL, *enc = NULL, keyiv[SSH_DIGEST_MAX_LENGTH]; 1637 struct sshcipher_ctx *cctx = NULL; 1638 const struct sshcipher *cipher; 1639 size_t i, enclen = 0; 1640 struct sshkey *kswap = NULL, tmp; 1641 int r = SSH_ERR_INTERNAL_ERROR; 1642 1643 #ifdef DEBUG_PK 1644 fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k)); 1645 #endif 1646 if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) { 1647 r = SSH_ERR_INVALID_ARGUMENT; 1648 goto out; 1649 } 1650 if (cipher_keylen(cipher) + cipher_ivlen(cipher) > 1651 ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) { 1652 r = SSH_ERR_INTERNAL_ERROR; 1653 goto out; 1654 } 1655 1656 /* Prepare a random pre-key, and from it an ephemeral key */ 1657 if ((r = sshkey_prekey_alloc(&prekey, SSHKEY_SHIELD_PREKEY_LEN)) != 0) 1658 goto out; 1659 arc4random_buf(prekey, SSHKEY_SHIELD_PREKEY_LEN); 1660 if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH, 1661 prekey, SSHKEY_SHIELD_PREKEY_LEN, 1662 keyiv, SSH_DIGEST_MAX_LENGTH)) != 0) 1663 goto out; 1664 #ifdef DEBUG_PK 1665 fprintf(stderr, "%s: key+iv\n", __func__); 1666 sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH), 1667 stderr); 1668 #endif 1669 if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher), 1670 keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 1)) != 0) 1671 goto out; 1672 1673 /* Serialise and encrypt the private key using the ephemeral key */ 1674 if ((prvbuf = sshbuf_new()) == NULL) { 1675 r = SSH_ERR_ALLOC_FAIL; 1676 goto out; 1677 } 1678 if (sshkey_is_shielded(k) && (r = sshkey_unshield_private(k)) != 0) 1679 goto out; 1680 if ((r = sshkey_private_serialize(k, prvbuf)) != 0) 1681 goto out; 1682 /* pad to cipher blocksize */ 1683 i = 0; 1684 while (sshbuf_len(prvbuf) % cipher_blocksize(cipher)) { 1685 if ((r = sshbuf_put_u8(prvbuf, ++i & 0xff)) != 0) 1686 goto out; 1687 } 1688 #ifdef DEBUG_PK 1689 fprintf(stderr, "%s: serialised\n", __func__); 1690 sshbuf_dump(prvbuf, stderr); 1691 #endif 1692 /* encrypt */ 1693 enclen = sshbuf_len(prvbuf); 1694 if ((enc = malloc(enclen)) == NULL) { 1695 r = SSH_ERR_ALLOC_FAIL; 1696 goto out; 1697 } 1698 if ((r = cipher_crypt(cctx, 0, enc, 1699 sshbuf_ptr(prvbuf), sshbuf_len(prvbuf), 0, 0)) != 0) 1700 goto out; 1701 #ifdef DEBUG_PK 1702 fprintf(stderr, "%s: encrypted\n", __func__); 1703 sshbuf_dump_data(enc, enclen, stderr); 1704 #endif 1705 1706 /* Make a scrubbed, public-only copy of our private key argument */ 1707 if ((r = sshkey_from_private(k, &kswap)) != 0) 1708 goto out; 1709 1710 /* Swap the private key out (it will be destroyed below) */ 1711 tmp = *kswap; 1712 *kswap = *k; 1713 *k = tmp; 1714 1715 /* Insert the shielded key into our argument */ 1716 k->shielded_private = enc; 1717 k->shielded_len = enclen; 1718 k->shield_prekey = prekey; 1719 k->shield_prekey_len = SSHKEY_SHIELD_PREKEY_LEN; 1720 enc = prekey = NULL; /* transferred */ 1721 enclen = 0; 1722 1723 /* preserve key fields that are required for correct operation */ 1724 k->sk_flags = kswap->sk_flags; 1725 1726 /* success */ 1727 r = 0; 1728 1729 out: 1730 /* XXX behaviour on error - invalidate original private key? */ 1731 cipher_free(cctx); 1732 explicit_bzero(keyiv, sizeof(keyiv)); 1733 explicit_bzero(&tmp, sizeof(tmp)); 1734 freezero(enc, enclen); 1735 sshkey_prekey_free(prekey, SSHKEY_SHIELD_PREKEY_LEN); 1736 sshkey_free(kswap); 1737 sshbuf_free(prvbuf); 1738 return r; 1739 } 1740 1741 /* Check deterministic padding after private key */ 1742 static int 1743 private2_check_padding(struct sshbuf *decrypted) 1744 { 1745 u_char pad; 1746 size_t i; 1747 int r; 1748 1749 i = 0; 1750 while (sshbuf_len(decrypted)) { 1751 if ((r = sshbuf_get_u8(decrypted, &pad)) != 0) 1752 goto out; 1753 if (pad != (++i & 0xff)) { 1754 r = SSH_ERR_INVALID_FORMAT; 1755 goto out; 1756 } 1757 } 1758 /* success */ 1759 r = 0; 1760 out: 1761 explicit_bzero(&pad, sizeof(pad)); 1762 explicit_bzero(&i, sizeof(i)); 1763 return r; 1764 } 1765 1766 int 1767 sshkey_unshield_private(struct sshkey *k) 1768 { 1769 struct sshbuf *prvbuf = NULL; 1770 u_char *cp, keyiv[SSH_DIGEST_MAX_LENGTH]; 1771 struct sshcipher_ctx *cctx = NULL; 1772 const struct sshcipher *cipher; 1773 struct sshkey *kswap = NULL, tmp; 1774 int r = SSH_ERR_INTERNAL_ERROR; 1775 1776 #ifdef DEBUG_PK 1777 fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k)); 1778 #endif 1779 if (!sshkey_is_shielded(k)) 1780 return 0; /* nothing to do */ 1781 1782 if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) { 1783 r = SSH_ERR_INVALID_ARGUMENT; 1784 goto out; 1785 } 1786 if (cipher_keylen(cipher) + cipher_ivlen(cipher) > 1787 ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) { 1788 r = SSH_ERR_INTERNAL_ERROR; 1789 goto out; 1790 } 1791 /* check size of shielded key blob */ 1792 if (k->shielded_len < cipher_blocksize(cipher) || 1793 (k->shielded_len % cipher_blocksize(cipher)) != 0) { 1794 r = SSH_ERR_INVALID_FORMAT; 1795 goto out; 1796 } 1797 1798 /* Calculate the ephemeral key from the prekey */ 1799 if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH, 1800 k->shield_prekey, k->shield_prekey_len, 1801 keyiv, SSH_DIGEST_MAX_LENGTH)) != 0) 1802 goto out; 1803 if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher), 1804 keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 0)) != 0) 1805 goto out; 1806 #ifdef DEBUG_PK 1807 fprintf(stderr, "%s: key+iv\n", __func__); 1808 sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH), 1809 stderr); 1810 #endif 1811 1812 /* Decrypt and parse the shielded private key using the ephemeral key */ 1813 if ((prvbuf = sshbuf_new()) == NULL) { 1814 r = SSH_ERR_ALLOC_FAIL; 1815 goto out; 1816 } 1817 if ((r = sshbuf_reserve(prvbuf, k->shielded_len, &cp)) != 0) 1818 goto out; 1819 /* decrypt */ 1820 #ifdef DEBUG_PK 1821 fprintf(stderr, "%s: encrypted\n", __func__); 1822 sshbuf_dump_data(k->shielded_private, k->shielded_len, stderr); 1823 #endif 1824 if ((r = cipher_crypt(cctx, 0, cp, 1825 k->shielded_private, k->shielded_len, 0, 0)) != 0) 1826 goto out; 1827 #ifdef DEBUG_PK 1828 fprintf(stderr, "%s: serialised\n", __func__); 1829 sshbuf_dump(prvbuf, stderr); 1830 #endif 1831 /* Parse private key */ 1832 if ((r = sshkey_private_deserialize(prvbuf, &kswap)) != 0) 1833 goto out; 1834 1835 if ((r = private2_check_padding(prvbuf)) != 0) 1836 goto out; 1837 1838 /* Swap the parsed key back into place */ 1839 tmp = *kswap; 1840 *kswap = *k; 1841 *k = tmp; 1842 1843 /* success */ 1844 r = 0; 1845 1846 out: 1847 cipher_free(cctx); 1848 explicit_bzero(keyiv, sizeof(keyiv)); 1849 explicit_bzero(&tmp, sizeof(tmp)); 1850 sshkey_free(kswap); 1851 sshbuf_free(prvbuf); 1852 return r; 1853 } 1854 1855 static int 1856 cert_parse(struct sshbuf *b, struct sshkey *key, struct sshbuf *certbuf) 1857 { 1858 struct sshbuf *principals = NULL, *crit = NULL; 1859 struct sshbuf *exts = NULL, *ca = NULL; 1860 u_char *sig = NULL; 1861 size_t signed_len = 0, slen = 0, kidlen = 0; 1862 int ret = SSH_ERR_INTERNAL_ERROR; 1863 1864 /* Copy the entire key blob for verification and later serialisation */ 1865 if ((ret = sshbuf_putb(key->cert->certblob, certbuf)) != 0) 1866 return ret; 1867 1868 /* Parse body of certificate up to signature */ 1869 if ((ret = sshbuf_get_u64(b, &key->cert->serial)) != 0 || 1870 (ret = sshbuf_get_u32(b, &key->cert->type)) != 0 || 1871 (ret = sshbuf_get_cstring(b, &key->cert->key_id, &kidlen)) != 0 || 1872 (ret = sshbuf_froms(b, &principals)) != 0 || 1873 (ret = sshbuf_get_u64(b, &key->cert->valid_after)) != 0 || 1874 (ret = sshbuf_get_u64(b, &key->cert->valid_before)) != 0 || 1875 (ret = sshbuf_froms(b, &crit)) != 0 || 1876 (ret = sshbuf_froms(b, &exts)) != 0 || 1877 (ret = sshbuf_get_string_direct(b, NULL, NULL)) != 0 || 1878 (ret = sshbuf_froms(b, &ca)) != 0) { 1879 /* XXX debug print error for ret */ 1880 ret = SSH_ERR_INVALID_FORMAT; 1881 goto out; 1882 } 1883 1884 /* Signature is left in the buffer so we can calculate this length */ 1885 signed_len = sshbuf_len(key->cert->certblob) - sshbuf_len(b); 1886 1887 if ((ret = sshbuf_get_string(b, &sig, &slen)) != 0) { 1888 ret = SSH_ERR_INVALID_FORMAT; 1889 goto out; 1890 } 1891 1892 if (key->cert->type != SSH2_CERT_TYPE_USER && 1893 key->cert->type != SSH2_CERT_TYPE_HOST) { 1894 ret = SSH_ERR_KEY_CERT_UNKNOWN_TYPE; 1895 goto out; 1896 } 1897 1898 /* Parse principals section */ 1899 while (sshbuf_len(principals) > 0) { 1900 char *principal = NULL; 1901 char **oprincipals = NULL; 1902 1903 if (key->cert->nprincipals >= SSHKEY_CERT_MAX_PRINCIPALS) { 1904 ret = SSH_ERR_INVALID_FORMAT; 1905 goto out; 1906 } 1907 if ((ret = sshbuf_get_cstring(principals, &principal, 1908 NULL)) != 0) { 1909 ret = SSH_ERR_INVALID_FORMAT; 1910 goto out; 1911 } 1912 oprincipals = key->cert->principals; 1913 key->cert->principals = recallocarray(key->cert->principals, 1914 key->cert->nprincipals, key->cert->nprincipals + 1, 1915 sizeof(*key->cert->principals)); 1916 if (key->cert->principals == NULL) { 1917 free(principal); 1918 key->cert->principals = oprincipals; 1919 ret = SSH_ERR_ALLOC_FAIL; 1920 goto out; 1921 } 1922 key->cert->principals[key->cert->nprincipals++] = principal; 1923 } 1924 1925 /* 1926 * Stash a copies of the critical options and extensions sections 1927 * for later use. 1928 */ 1929 if ((ret = sshbuf_putb(key->cert->critical, crit)) != 0 || 1930 (exts != NULL && 1931 (ret = sshbuf_putb(key->cert->extensions, exts)) != 0)) 1932 goto out; 1933 1934 /* 1935 * Validate critical options and extensions sections format. 1936 */ 1937 while (sshbuf_len(crit) != 0) { 1938 if ((ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0 || 1939 (ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0) { 1940 sshbuf_reset(key->cert->critical); 1941 ret = SSH_ERR_INVALID_FORMAT; 1942 goto out; 1943 } 1944 } 1945 while (exts != NULL && sshbuf_len(exts) != 0) { 1946 if ((ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0 || 1947 (ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0) { 1948 sshbuf_reset(key->cert->extensions); 1949 ret = SSH_ERR_INVALID_FORMAT; 1950 goto out; 1951 } 1952 } 1953 1954 /* Parse CA key and check signature */ 1955 if (sshkey_from_blob_internal(ca, &key->cert->signature_key, 0) != 0) { 1956 ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 1957 goto out; 1958 } 1959 if (!sshkey_type_is_valid_ca(key->cert->signature_key->type)) { 1960 ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 1961 goto out; 1962 } 1963 if ((ret = sshkey_verify(key->cert->signature_key, sig, slen, 1964 sshbuf_ptr(key->cert->certblob), signed_len, NULL, 0, NULL)) != 0) 1965 goto out; 1966 if ((ret = sshkey_get_sigtype(sig, slen, 1967 &key->cert->signature_type)) != 0) 1968 goto out; 1969 1970 /* Success */ 1971 ret = 0; 1972 out: 1973 sshbuf_free(ca); 1974 sshbuf_free(crit); 1975 sshbuf_free(exts); 1976 sshbuf_free(principals); 1977 free(sig); 1978 return ret; 1979 } 1980 1981 int 1982 sshkey_deserialize_sk(struct sshbuf *b, struct sshkey *key) 1983 { 1984 /* Parse additional security-key application string */ 1985 if (sshbuf_get_cstring(b, &key->sk_application, NULL) != 0) 1986 return SSH_ERR_INVALID_FORMAT; 1987 return 0; 1988 } 1989 1990 static int 1991 sshkey_from_blob_internal(struct sshbuf *b, struct sshkey **keyp, 1992 int allow_cert) 1993 { 1994 int type, ret = SSH_ERR_INTERNAL_ERROR; 1995 char *ktype = NULL; 1996 struct sshkey *key = NULL; 1997 struct sshbuf *copy; 1998 const struct sshkey_impl *impl; 1999 2000 #ifdef DEBUG_PK /* XXX */ 2001 sshbuf_dump(b, stderr); 2002 #endif 2003 if (keyp != NULL) 2004 *keyp = NULL; 2005 if ((copy = sshbuf_fromb(b)) == NULL) { 2006 ret = SSH_ERR_ALLOC_FAIL; 2007 goto out; 2008 } 2009 if (sshbuf_get_cstring(b, &ktype, NULL) != 0) { 2010 ret = SSH_ERR_INVALID_FORMAT; 2011 goto out; 2012 } 2013 2014 type = sshkey_type_from_name(ktype); 2015 if (!allow_cert && sshkey_type_is_cert(type)) { 2016 ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 2017 goto out; 2018 } 2019 if ((impl = sshkey_impl_from_type(type)) == NULL) { 2020 ret = SSH_ERR_KEY_TYPE_UNKNOWN; 2021 goto out; 2022 } 2023 if ((key = sshkey_new(type)) == NULL) { 2024 ret = SSH_ERR_ALLOC_FAIL; 2025 goto out; 2026 } 2027 if (sshkey_type_is_cert(type)) { 2028 /* Skip nonce that precedes all certificates */ 2029 if (sshbuf_get_string_direct(b, NULL, NULL) != 0) { 2030 ret = SSH_ERR_INVALID_FORMAT; 2031 goto out; 2032 } 2033 } 2034 if ((ret = impl->funcs->deserialize_public(ktype, b, key)) != 0) 2035 goto out; 2036 2037 /* Parse certificate potion */ 2038 if (sshkey_is_cert(key) && (ret = cert_parse(b, key, copy)) != 0) 2039 goto out; 2040 2041 if (key != NULL && sshbuf_len(b) != 0) { 2042 ret = SSH_ERR_INVALID_FORMAT; 2043 goto out; 2044 } 2045 ret = 0; 2046 if (keyp != NULL) { 2047 *keyp = key; 2048 key = NULL; 2049 } 2050 out: 2051 sshbuf_free(copy); 2052 sshkey_free(key); 2053 free(ktype); 2054 return ret; 2055 } 2056 2057 int 2058 sshkey_from_blob(const u_char *blob, size_t blen, struct sshkey **keyp) 2059 { 2060 struct sshbuf *b; 2061 int r; 2062 2063 if ((b = sshbuf_from(blob, blen)) == NULL) 2064 return SSH_ERR_ALLOC_FAIL; 2065 r = sshkey_from_blob_internal(b, keyp, 1); 2066 sshbuf_free(b); 2067 return r; 2068 } 2069 2070 int 2071 sshkey_fromb(struct sshbuf *b, struct sshkey **keyp) 2072 { 2073 return sshkey_from_blob_internal(b, keyp, 1); 2074 } 2075 2076 int 2077 sshkey_froms(struct sshbuf *buf, struct sshkey **keyp) 2078 { 2079 struct sshbuf *b; 2080 int r; 2081 2082 if ((r = sshbuf_froms(buf, &b)) != 0) 2083 return r; 2084 r = sshkey_from_blob_internal(b, keyp, 1); 2085 sshbuf_free(b); 2086 return r; 2087 } 2088 2089 int 2090 sshkey_get_sigtype(const u_char *sig, size_t siglen, char **sigtypep) 2091 { 2092 int r; 2093 struct sshbuf *b = NULL; 2094 char *sigtype = NULL; 2095 2096 if (sigtypep != NULL) 2097 *sigtypep = NULL; 2098 if ((b = sshbuf_from(sig, siglen)) == NULL) 2099 return SSH_ERR_ALLOC_FAIL; 2100 if ((r = sshbuf_get_cstring(b, &sigtype, NULL)) != 0) 2101 goto out; 2102 /* success */ 2103 if (sigtypep != NULL) { 2104 *sigtypep = sigtype; 2105 sigtype = NULL; 2106 } 2107 r = 0; 2108 out: 2109 free(sigtype); 2110 sshbuf_free(b); 2111 return r; 2112 } 2113 2114 /* 2115 * 2116 * Checks whether a certificate's signature type is allowed. 2117 * Returns 0 (success) if the certificate signature type appears in the 2118 * "allowed" pattern-list, or the key is not a certificate to begin with. 2119 * Otherwise returns a ssherr.h code. 2120 */ 2121 int 2122 sshkey_check_cert_sigtype(const struct sshkey *key, const char *allowed) 2123 { 2124 if (key == NULL || allowed == NULL) 2125 return SSH_ERR_INVALID_ARGUMENT; 2126 if (!sshkey_type_is_cert(key->type)) 2127 return 0; 2128 if (key->cert == NULL || key->cert->signature_type == NULL) 2129 return SSH_ERR_INVALID_ARGUMENT; 2130 if (match_pattern_list(key->cert->signature_type, allowed, 0) != 1) 2131 return SSH_ERR_SIGN_ALG_UNSUPPORTED; 2132 return 0; 2133 } 2134 2135 /* 2136 * Returns the expected signature algorithm for a given public key algorithm. 2137 */ 2138 const char * 2139 sshkey_sigalg_by_name(const char *name) 2140 { 2141 const struct sshkey_impl *impl; 2142 int i; 2143 2144 for (i = 0; keyimpls[i] != NULL; i++) { 2145 impl = keyimpls[i]; 2146 if (strcmp(impl->name, name) != 0) 2147 continue; 2148 if (impl->sigalg != NULL) 2149 return impl->sigalg; 2150 if (!impl->cert) 2151 return impl->name; 2152 return sshkey_ssh_name_from_type_nid( 2153 sshkey_type_plain(impl->type), impl->nid); 2154 } 2155 return NULL; 2156 } 2157 2158 /* 2159 * Verifies that the signature algorithm appearing inside the signature blob 2160 * matches that which was requested. 2161 */ 2162 int 2163 sshkey_check_sigtype(const u_char *sig, size_t siglen, 2164 const char *requested_alg) 2165 { 2166 const char *expected_alg; 2167 char *sigtype = NULL; 2168 int r; 2169 2170 if (requested_alg == NULL) 2171 return 0; 2172 if ((expected_alg = sshkey_sigalg_by_name(requested_alg)) == NULL) 2173 return SSH_ERR_INVALID_ARGUMENT; 2174 if ((r = sshkey_get_sigtype(sig, siglen, &sigtype)) != 0) 2175 return r; 2176 r = strcmp(expected_alg, sigtype) == 0; 2177 free(sigtype); 2178 return r ? 0 : SSH_ERR_SIGN_ALG_UNSUPPORTED; 2179 } 2180 2181 int 2182 sshkey_sign(struct sshkey *key, 2183 u_char **sigp, size_t *lenp, 2184 const u_char *data, size_t datalen, 2185 const char *alg, const char *sk_provider, const char *sk_pin, u_int compat) 2186 { 2187 int was_shielded = sshkey_is_shielded(key); 2188 int r2, r = SSH_ERR_INTERNAL_ERROR; 2189 const struct sshkey_impl *impl; 2190 2191 if (sigp != NULL) 2192 *sigp = NULL; 2193 if (lenp != NULL) 2194 *lenp = 0; 2195 if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE) 2196 return SSH_ERR_INVALID_ARGUMENT; 2197 if ((impl = sshkey_impl_from_key(key)) == NULL) 2198 return SSH_ERR_KEY_TYPE_UNKNOWN; 2199 if ((r = sshkey_unshield_private(key)) != 0) 2200 return r; 2201 if (sshkey_is_sk(key)) { 2202 r = sshsk_sign(sk_provider, key, sigp, lenp, data, 2203 datalen, compat, sk_pin); 2204 } else if ((key->flags & SSHKEY_FLAG_EXT) != 0) { 2205 r = pkcs11_sign(key, sigp, lenp, data, datalen, 2206 alg, sk_provider, sk_pin, compat); 2207 } else { 2208 if (impl->funcs->sign == NULL) 2209 r = SSH_ERR_SIGN_ALG_UNSUPPORTED; 2210 else { 2211 r = impl->funcs->sign(key, sigp, lenp, data, datalen, 2212 alg, sk_provider, sk_pin, compat); 2213 } 2214 } 2215 if (was_shielded && (r2 = sshkey_shield_private(key)) != 0) 2216 return r2; 2217 return r; 2218 } 2219 2220 /* 2221 * ssh_key_verify returns 0 for a correct signature and < 0 on error. 2222 * If "alg" specified, then the signature must use that algorithm. 2223 */ 2224 int 2225 sshkey_verify(const struct sshkey *key, 2226 const u_char *sig, size_t siglen, 2227 const u_char *data, size_t dlen, const char *alg, u_int compat, 2228 struct sshkey_sig_details **detailsp) 2229 { 2230 const struct sshkey_impl *impl; 2231 2232 if (detailsp != NULL) 2233 *detailsp = NULL; 2234 if (siglen == 0 || dlen > SSH_KEY_MAX_SIGN_DATA_SIZE) 2235 return SSH_ERR_INVALID_ARGUMENT; 2236 if ((impl = sshkey_impl_from_key(key)) == NULL) 2237 return SSH_ERR_KEY_TYPE_UNKNOWN; 2238 return impl->funcs->verify(key, sig, siglen, data, dlen, 2239 alg, compat, detailsp); 2240 } 2241 2242 /* Convert a plain key to their _CERT equivalent */ 2243 int 2244 sshkey_to_certified(struct sshkey *k) 2245 { 2246 int newtype; 2247 2248 if ((newtype = sshkey_type_certified(k->type)) == -1) 2249 return SSH_ERR_INVALID_ARGUMENT; 2250 if ((k->cert = cert_new()) == NULL) 2251 return SSH_ERR_ALLOC_FAIL; 2252 k->type = newtype; 2253 return 0; 2254 } 2255 2256 /* Convert a certificate to its raw key equivalent */ 2257 int 2258 sshkey_drop_cert(struct sshkey *k) 2259 { 2260 if (!sshkey_type_is_cert(k->type)) 2261 return SSH_ERR_KEY_TYPE_UNKNOWN; 2262 cert_free(k->cert); 2263 k->cert = NULL; 2264 k->type = sshkey_type_plain(k->type); 2265 return 0; 2266 } 2267 2268 /* Sign a certified key, (re-)generating the signed certblob. */ 2269 int 2270 sshkey_certify_custom(struct sshkey *k, struct sshkey *ca, const char *alg, 2271 const char *sk_provider, const char *sk_pin, 2272 sshkey_certify_signer *signer, void *signer_ctx) 2273 { 2274 const struct sshkey_impl *impl; 2275 struct sshbuf *principals = NULL; 2276 u_char *ca_blob = NULL, *sig_blob = NULL, nonce[32]; 2277 size_t i, ca_len, sig_len; 2278 int ret = SSH_ERR_INTERNAL_ERROR; 2279 struct sshbuf *cert = NULL; 2280 char *sigtype = NULL; 2281 2282 if (k == NULL || k->cert == NULL || 2283 k->cert->certblob == NULL || ca == NULL) 2284 return SSH_ERR_INVALID_ARGUMENT; 2285 if (!sshkey_is_cert(k)) 2286 return SSH_ERR_KEY_TYPE_UNKNOWN; 2287 if (!sshkey_type_is_valid_ca(ca->type)) 2288 return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 2289 if ((impl = sshkey_impl_from_key(k)) == NULL) 2290 return SSH_ERR_INTERNAL_ERROR; 2291 2292 /* 2293 * If no alg specified as argument but a signature_type was set, 2294 * then prefer that. If both were specified, then they must match. 2295 */ 2296 if (alg == NULL) 2297 alg = k->cert->signature_type; 2298 else if (k->cert->signature_type != NULL && 2299 strcmp(alg, k->cert->signature_type) != 0) 2300 return SSH_ERR_INVALID_ARGUMENT; 2301 2302 /* 2303 * If no signing algorithm or signature_type was specified and we're 2304 * using a RSA key, then default to a good signature algorithm. 2305 */ 2306 if (alg == NULL && ca->type == KEY_RSA) 2307 alg = "rsa-sha2-512"; 2308 2309 if ((ret = sshkey_to_blob(ca, &ca_blob, &ca_len)) != 0) 2310 return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 2311 2312 cert = k->cert->certblob; /* for readability */ 2313 sshbuf_reset(cert); 2314 if ((ret = sshbuf_put_cstring(cert, sshkey_ssh_name(k))) != 0) 2315 goto out; 2316 2317 /* -v01 certs put nonce first */ 2318 arc4random_buf(&nonce, sizeof(nonce)); 2319 if ((ret = sshbuf_put_string(cert, nonce, sizeof(nonce))) != 0) 2320 goto out; 2321 2322 /* Public key next */ 2323 if ((ret = impl->funcs->serialize_public(k, cert, 2324 SSHKEY_SERIALIZE_DEFAULT)) != 0) 2325 goto out; 2326 2327 /* Then remaining cert fields */ 2328 if ((ret = sshbuf_put_u64(cert, k->cert->serial)) != 0 || 2329 (ret = sshbuf_put_u32(cert, k->cert->type)) != 0 || 2330 (ret = sshbuf_put_cstring(cert, k->cert->key_id)) != 0) 2331 goto out; 2332 2333 if ((principals = sshbuf_new()) == NULL) { 2334 ret = SSH_ERR_ALLOC_FAIL; 2335 goto out; 2336 } 2337 for (i = 0; i < k->cert->nprincipals; i++) { 2338 if ((ret = sshbuf_put_cstring(principals, 2339 k->cert->principals[i])) != 0) 2340 goto out; 2341 } 2342 if ((ret = sshbuf_put_stringb(cert, principals)) != 0 || 2343 (ret = sshbuf_put_u64(cert, k->cert->valid_after)) != 0 || 2344 (ret = sshbuf_put_u64(cert, k->cert->valid_before)) != 0 || 2345 (ret = sshbuf_put_stringb(cert, k->cert->critical)) != 0 || 2346 (ret = sshbuf_put_stringb(cert, k->cert->extensions)) != 0 || 2347 (ret = sshbuf_put_string(cert, NULL, 0)) != 0 || /* Reserved */ 2348 (ret = sshbuf_put_string(cert, ca_blob, ca_len)) != 0) 2349 goto out; 2350 2351 /* Sign the whole mess */ 2352 if ((ret = signer(ca, &sig_blob, &sig_len, sshbuf_ptr(cert), 2353 sshbuf_len(cert), alg, sk_provider, sk_pin, 0, signer_ctx)) != 0) 2354 goto out; 2355 /* Check and update signature_type against what was actually used */ 2356 if ((ret = sshkey_get_sigtype(sig_blob, sig_len, &sigtype)) != 0) 2357 goto out; 2358 if (alg != NULL && strcmp(alg, sigtype) != 0) { 2359 ret = SSH_ERR_SIGN_ALG_UNSUPPORTED; 2360 goto out; 2361 } 2362 if (k->cert->signature_type == NULL) { 2363 k->cert->signature_type = sigtype; 2364 sigtype = NULL; 2365 } 2366 /* Append signature and we are done */ 2367 if ((ret = sshbuf_put_string(cert, sig_blob, sig_len)) != 0) 2368 goto out; 2369 ret = 0; 2370 out: 2371 if (ret != 0) 2372 sshbuf_reset(cert); 2373 free(sig_blob); 2374 free(ca_blob); 2375 free(sigtype); 2376 sshbuf_free(principals); 2377 return ret; 2378 } 2379 2380 static int 2381 default_key_sign(struct sshkey *key, u_char **sigp, size_t *lenp, 2382 const u_char *data, size_t datalen, 2383 const char *alg, const char *sk_provider, const char *sk_pin, 2384 u_int compat, void *ctx) 2385 { 2386 if (ctx != NULL) 2387 return SSH_ERR_INVALID_ARGUMENT; 2388 return sshkey_sign(key, sigp, lenp, data, datalen, alg, 2389 sk_provider, sk_pin, compat); 2390 } 2391 2392 int 2393 sshkey_certify(struct sshkey *k, struct sshkey *ca, const char *alg, 2394 const char *sk_provider, const char *sk_pin) 2395 { 2396 return sshkey_certify_custom(k, ca, alg, sk_provider, sk_pin, 2397 default_key_sign, NULL); 2398 } 2399 2400 int 2401 sshkey_cert_check_authority(const struct sshkey *k, 2402 int want_host, int wildcard_pattern, uint64_t verify_time, 2403 const char *name, const char **reason) 2404 { 2405 u_int i, principal_matches; 2406 2407 if (reason == NULL) 2408 return SSH_ERR_INVALID_ARGUMENT; 2409 if (!sshkey_is_cert(k)) { 2410 *reason = "Key is not a certificate"; 2411 return SSH_ERR_KEY_CERT_INVALID; 2412 } 2413 if (want_host) { 2414 if (k->cert->type != SSH2_CERT_TYPE_HOST) { 2415 *reason = "Certificate invalid: not a host certificate"; 2416 return SSH_ERR_KEY_CERT_INVALID; 2417 } 2418 } else { 2419 if (k->cert->type != SSH2_CERT_TYPE_USER) { 2420 *reason = "Certificate invalid: not a user certificate"; 2421 return SSH_ERR_KEY_CERT_INVALID; 2422 } 2423 } 2424 if (verify_time < k->cert->valid_after) { 2425 *reason = "Certificate invalid: not yet valid"; 2426 return SSH_ERR_KEY_CERT_INVALID; 2427 } 2428 if (verify_time >= k->cert->valid_before) { 2429 *reason = "Certificate invalid: expired"; 2430 return SSH_ERR_KEY_CERT_INVALID; 2431 } 2432 if (k->cert->nprincipals == 0) { 2433 *reason = "Certificate lacks principal list"; 2434 return SSH_ERR_KEY_CERT_INVALID; 2435 } 2436 if (name == NULL) 2437 return 0; /* principal matching not requested */ 2438 2439 principal_matches = 0; 2440 for (i = 0; i < k->cert->nprincipals; i++) { 2441 if (wildcard_pattern) { 2442 if (match_pattern(name, k->cert->principals[i])) { 2443 principal_matches = 1; 2444 break; 2445 } 2446 } else if (strcmp(name, k->cert->principals[i]) == 0) { 2447 principal_matches = 1; 2448 break; 2449 } 2450 } 2451 if (!principal_matches) { 2452 *reason = "Certificate invalid: name is not a listed " 2453 "principal"; 2454 return SSH_ERR_KEY_CERT_INVALID; 2455 } 2456 return 0; 2457 } 2458 2459 int 2460 sshkey_cert_check_authority_now(const struct sshkey *k, 2461 int want_host, int wildcard_pattern, const char *name, 2462 const char **reason) 2463 { 2464 time_t now; 2465 2466 if ((now = time(NULL)) < 0) { 2467 /* yikes - system clock before epoch! */ 2468 *reason = "Certificate invalid: not yet valid"; 2469 return SSH_ERR_KEY_CERT_INVALID; 2470 } 2471 return sshkey_cert_check_authority(k, want_host, wildcard_pattern, 2472 (uint64_t)now, name, reason); 2473 } 2474 2475 int 2476 sshkey_cert_check_host(const struct sshkey *key, const char *host, 2477 const char *ca_sign_algorithms, const char **reason) 2478 { 2479 int r; 2480 2481 if ((r = sshkey_cert_check_authority_now(key, 1, 1, host, reason)) != 0) 2482 return r; 2483 if (sshbuf_len(key->cert->critical) != 0) { 2484 *reason = "Certificate contains unsupported critical options"; 2485 return SSH_ERR_KEY_CERT_INVALID; 2486 } 2487 if (ca_sign_algorithms != NULL && 2488 (r = sshkey_check_cert_sigtype(key, ca_sign_algorithms)) != 0) { 2489 *reason = "Certificate signed with disallowed algorithm"; 2490 return SSH_ERR_KEY_CERT_INVALID; 2491 } 2492 return 0; 2493 } 2494 2495 size_t 2496 sshkey_format_cert_validity(const struct sshkey_cert *cert, char *s, size_t l) 2497 { 2498 char from[32], to[32], ret[128]; 2499 2500 *from = *to = '\0'; 2501 if (cert->valid_after == 0 && 2502 cert->valid_before == 0xffffffffffffffffULL) 2503 return strlcpy(s, "forever", l); 2504 2505 if (cert->valid_after != 0) 2506 format_absolute_time(cert->valid_after, from, sizeof(from)); 2507 if (cert->valid_before != 0xffffffffffffffffULL) 2508 format_absolute_time(cert->valid_before, to, sizeof(to)); 2509 2510 if (cert->valid_after == 0) 2511 snprintf(ret, sizeof(ret), "before %s", to); 2512 else if (cert->valid_before == 0xffffffffffffffffULL) 2513 snprintf(ret, sizeof(ret), "after %s", from); 2514 else 2515 snprintf(ret, sizeof(ret), "from %s to %s", from, to); 2516 2517 return strlcpy(s, ret, l); 2518 } 2519 2520 /* Common serialization for FIDO private keys */ 2521 int 2522 sshkey_serialize_private_sk(const struct sshkey *key, struct sshbuf *b) 2523 { 2524 int r; 2525 2526 if ((r = sshbuf_put_cstring(b, key->sk_application)) != 0 || 2527 (r = sshbuf_put_u8(b, key->sk_flags)) != 0 || 2528 (r = sshbuf_put_stringb(b, key->sk_key_handle)) != 0 || 2529 (r = sshbuf_put_stringb(b, key->sk_reserved)) != 0) 2530 return r; 2531 2532 return 0; 2533 } 2534 2535 static int 2536 sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf, 2537 enum sshkey_serialize_rep opts) 2538 { 2539 int r = SSH_ERR_INTERNAL_ERROR; 2540 int was_shielded = sshkey_is_shielded(key); 2541 struct sshbuf *b = NULL; 2542 const struct sshkey_impl *impl; 2543 2544 if ((impl = sshkey_impl_from_key(key)) == NULL) 2545 return SSH_ERR_INTERNAL_ERROR; 2546 if ((r = sshkey_unshield_private(key)) != 0) 2547 return r; 2548 if ((b = sshbuf_new()) == NULL) 2549 return SSH_ERR_ALLOC_FAIL; 2550 if ((r = sshbuf_put_cstring(b, sshkey_ssh_name(key))) != 0) 2551 goto out; 2552 if (sshkey_is_cert(key)) { 2553 if (key->cert == NULL || 2554 sshbuf_len(key->cert->certblob) == 0) { 2555 r = SSH_ERR_INVALID_ARGUMENT; 2556 goto out; 2557 } 2558 if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0) 2559 goto out; 2560 } 2561 if ((r = impl->funcs->serialize_private(key, b, opts)) != 0) 2562 goto out; 2563 2564 /* 2565 * success (but we still need to append the output to buf after 2566 * possibly re-shielding the private key) 2567 */ 2568 r = 0; 2569 out: 2570 if (was_shielded) 2571 r = sshkey_shield_private(key); 2572 if (r == 0) 2573 r = sshbuf_putb(buf, b); 2574 sshbuf_free(b); 2575 2576 return r; 2577 } 2578 2579 int 2580 sshkey_private_serialize(struct sshkey *key, struct sshbuf *b) 2581 { 2582 return sshkey_private_serialize_opt(key, b, 2583 SSHKEY_SERIALIZE_DEFAULT); 2584 } 2585 2586 2587 /* Shared deserialization of FIDO private key components */ 2588 int 2589 sshkey_private_deserialize_sk(struct sshbuf *buf, struct sshkey *k) 2590 { 2591 int r; 2592 2593 if ((k->sk_key_handle = sshbuf_new()) == NULL || 2594 (k->sk_reserved = sshbuf_new()) == NULL) 2595 return SSH_ERR_ALLOC_FAIL; 2596 if ((r = sshbuf_get_cstring(buf, &k->sk_application, NULL)) != 0 || 2597 (r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 || 2598 (r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 || 2599 (r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0) 2600 return r; 2601 2602 return 0; 2603 } 2604 2605 int 2606 sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp) 2607 { 2608 const struct sshkey_impl *impl; 2609 char *tname = NULL; 2610 char *expect_sk_application = NULL; 2611 u_char *expect_ed25519_pk = NULL; 2612 struct sshkey *k = NULL; 2613 int type, r = SSH_ERR_INTERNAL_ERROR; 2614 2615 if (kp != NULL) 2616 *kp = NULL; 2617 if ((r = sshbuf_get_cstring(buf, &tname, NULL)) != 0) 2618 goto out; 2619 type = sshkey_type_from_name(tname); 2620 if (sshkey_type_is_cert(type)) { 2621 /* 2622 * Certificate key private keys begin with the certificate 2623 * itself. Make sure this matches the type of the enclosing 2624 * private key. 2625 */ 2626 if ((r = sshkey_froms(buf, &k)) != 0) 2627 goto out; 2628 if (k->type != type) { 2629 r = SSH_ERR_KEY_CERT_MISMATCH; 2630 goto out; 2631 } 2632 /* For ECDSA keys, the group must match too */ 2633 if (k->type == KEY_ECDSA && 2634 k->ecdsa_nid != sshkey_ecdsa_nid_from_name(tname)) { 2635 r = SSH_ERR_KEY_CERT_MISMATCH; 2636 goto out; 2637 } 2638 /* 2639 * Several fields are redundant between certificate and 2640 * private key body, we require these to match. 2641 */ 2642 expect_sk_application = k->sk_application; 2643 expect_ed25519_pk = k->ed25519_pk; 2644 k->sk_application = NULL; 2645 k->ed25519_pk = NULL; 2646 } else { 2647 if ((k = sshkey_new(type)) == NULL) { 2648 r = SSH_ERR_ALLOC_FAIL; 2649 goto out; 2650 } 2651 } 2652 if ((impl = sshkey_impl_from_type(type)) == NULL) { 2653 r = SSH_ERR_INTERNAL_ERROR; 2654 goto out; 2655 } 2656 if ((r = impl->funcs->deserialize_private(tname, buf, k)) != 0) 2657 goto out; 2658 2659 if ((expect_sk_application != NULL && (k->sk_application == NULL || 2660 strcmp(expect_sk_application, k->sk_application) != 0)) || 2661 (expect_ed25519_pk != NULL && (k->ed25519_pk == NULL || 2662 memcmp(expect_ed25519_pk, k->ed25519_pk, ED25519_PK_SZ) != 0))) { 2663 r = SSH_ERR_KEY_CERT_MISMATCH; 2664 goto out; 2665 } 2666 /* success */ 2667 r = 0; 2668 if (kp != NULL) { 2669 *kp = k; 2670 k = NULL; 2671 } 2672 out: 2673 free(tname); 2674 sshkey_free(k); 2675 free(expect_sk_application); 2676 free(expect_ed25519_pk); 2677 return r; 2678 } 2679 2680 #if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) 2681 int 2682 sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public) 2683 { 2684 EC_POINT *nq = NULL; 2685 BIGNUM *order = NULL, *cofactor = NULL; 2686 int ret = SSH_ERR_KEY_INVALID_EC_VALUE; 2687 2688 /* 2689 * NB. This assumes OpenSSL has already verified that the public 2690 * point lies on the curve and that its coordinates are in [0, p). 2691 * This is done by EC_POINT_oct2point() on at least OpenSSL >= 1.1, 2692 * LibreSSL and BoringSSL. 2693 */ 2694 2695 /* Q != infinity */ 2696 if (EC_POINT_is_at_infinity(group, public)) 2697 goto out; 2698 2699 if ((cofactor = BN_new()) == NULL) { 2700 ret = SSH_ERR_ALLOC_FAIL; 2701 goto out; 2702 } 2703 if (EC_GROUP_get_cofactor(group, cofactor, NULL) != 1) 2704 goto out; 2705 2706 /* 2707 * Verify nQ == infinity (n == order of subgroup) 2708 * This check may be skipped for curves with cofactor 1, as per 2709 * NIST SP 800-56A, 5.6.2.3. 2710 */ 2711 if (!BN_is_one(cofactor)) { 2712 if ((order = BN_new()) == NULL) { 2713 ret = SSH_ERR_ALLOC_FAIL; 2714 goto out; 2715 } 2716 if ((nq = EC_POINT_new(group)) == NULL) { 2717 ret = SSH_ERR_ALLOC_FAIL; 2718 goto out; 2719 } 2720 if (EC_POINT_mul(group, nq, NULL, public, order, NULL) != 1) { 2721 ret = SSH_ERR_LIBCRYPTO_ERROR; 2722 goto out; 2723 } 2724 if (EC_POINT_is_at_infinity(group, nq) != 1) 2725 goto out; 2726 } 2727 2728 /* success */ 2729 ret = 0; 2730 out: 2731 BN_clear_free(cofactor); 2732 BN_clear_free(order); 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 #ifdef OPENSSL_HAS_ED25519 3325 case KEY_ED25519: 3326 if (format == SSHKEY_PRIVATE_PEM) { 3327 r = SSH_ERR_INVALID_FORMAT; 3328 goto out; 3329 } else { 3330 pkey = EVP_PKEY_new_raw_private_key(EVP_PKEY_ED25519, 3331 NULL, key->ed25519_sk, 3332 ED25519_SK_SZ - ED25519_PK_SZ); 3333 success = pkey != NULL; 3334 } 3335 break; 3336 #endif 3337 default: 3338 success = 0; 3339 break; 3340 } 3341 if (success == 0) { 3342 r = SSH_ERR_LIBCRYPTO_ERROR; 3343 goto out; 3344 } 3345 if (format == SSHKEY_PRIVATE_PKCS8) { 3346 if ((success = PEM_write_bio_PrivateKey(bio, pkey, cipher, 3347 passphrase, len, NULL, NULL)) == 0) { 3348 r = SSH_ERR_LIBCRYPTO_ERROR; 3349 goto out; 3350 } 3351 } 3352 if ((blen = BIO_get_mem_data(bio, &bptr)) <= 0) { 3353 r = SSH_ERR_INTERNAL_ERROR; 3354 goto out; 3355 } 3356 if ((r = sshbuf_put(blob, bptr, blen)) != 0) 3357 goto out; 3358 r = 0; 3359 out: 3360 if (was_shielded) 3361 r = sshkey_shield_private(key); 3362 if (r == 0) 3363 r = sshbuf_putb(buf, blob); 3364 3365 EVP_PKEY_free(pkey); 3366 sshbuf_free(blob); 3367 BIO_free(bio); 3368 return r; 3369 } 3370 #endif /* WITH_OPENSSL */ 3371 3372 /* Serialise "key" to buffer "blob" */ 3373 int 3374 sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob, 3375 const char *passphrase, const char *comment, 3376 int format, const char *openssh_format_cipher, int openssh_format_rounds) 3377 { 3378 switch (key->type) { 3379 #ifdef WITH_OPENSSL 3380 case KEY_ECDSA: 3381 case KEY_RSA: 3382 case KEY_ED25519: 3383 break; /* see below */ 3384 #else /* WITH_OPENSSL */ 3385 case KEY_ED25519: 3386 #endif /* WITH_OPENSSL */ 3387 case KEY_ED25519_SK: 3388 #ifdef WITH_OPENSSL 3389 case KEY_ECDSA_SK: 3390 #endif /* WITH_OPENSSL */ 3391 return sshkey_private_to_blob2(key, blob, passphrase, 3392 comment, openssh_format_cipher, openssh_format_rounds); 3393 default: 3394 return SSH_ERR_KEY_TYPE_UNKNOWN; 3395 } 3396 3397 #ifdef WITH_OPENSSL 3398 switch (format) { 3399 case SSHKEY_PRIVATE_OPENSSH: 3400 return sshkey_private_to_blob2(key, blob, passphrase, 3401 comment, openssh_format_cipher, openssh_format_rounds); 3402 case SSHKEY_PRIVATE_PEM: 3403 case SSHKEY_PRIVATE_PKCS8: 3404 return sshkey_private_to_blob_pem_pkcs8(key, blob, 3405 format, passphrase, comment); 3406 default: 3407 return SSH_ERR_INVALID_ARGUMENT; 3408 } 3409 #endif /* WITH_OPENSSL */ 3410 } 3411 3412 #ifdef WITH_OPENSSL 3413 static int 3414 translate_libcrypto_error(unsigned long pem_err) 3415 { 3416 int pem_reason = ERR_GET_REASON(pem_err); 3417 3418 switch (ERR_GET_LIB(pem_err)) { 3419 case ERR_LIB_PEM: 3420 switch (pem_reason) { 3421 case PEM_R_BAD_PASSWORD_READ: 3422 #ifdef PEM_R_PROBLEMS_GETTING_PASSWORD 3423 case PEM_R_PROBLEMS_GETTING_PASSWORD: 3424 #endif 3425 #ifdef PEM_R_BAD_DECRYPT 3426 case PEM_R_BAD_DECRYPT: 3427 #endif 3428 return SSH_ERR_KEY_WRONG_PASSPHRASE; 3429 default: 3430 return SSH_ERR_INVALID_FORMAT; 3431 } 3432 case ERR_LIB_EVP: 3433 switch (pem_reason) { 3434 #ifdef EVP_R_BAD_DECRYPT 3435 case EVP_R_BAD_DECRYPT: 3436 return SSH_ERR_KEY_WRONG_PASSPHRASE; 3437 #endif 3438 #ifdef EVP_R_BN_DECODE_ERROR 3439 case EVP_R_BN_DECODE_ERROR: 3440 #endif 3441 case EVP_R_DECODE_ERROR: 3442 #ifdef EVP_R_PRIVATE_KEY_DECODE_ERROR 3443 case EVP_R_PRIVATE_KEY_DECODE_ERROR: 3444 #endif 3445 return SSH_ERR_INVALID_FORMAT; 3446 default: 3447 return SSH_ERR_LIBCRYPTO_ERROR; 3448 } 3449 case ERR_LIB_ASN1: 3450 return SSH_ERR_INVALID_FORMAT; 3451 } 3452 return SSH_ERR_LIBCRYPTO_ERROR; 3453 } 3454 3455 static void 3456 clear_libcrypto_errors(void) 3457 { 3458 while (ERR_get_error() != 0) 3459 ; 3460 } 3461 3462 /* 3463 * Translate OpenSSL error codes to determine whether 3464 * passphrase is required/incorrect. 3465 */ 3466 static int 3467 convert_libcrypto_error(void) 3468 { 3469 /* 3470 * Some password errors are reported at the beginning 3471 * of the error queue. 3472 */ 3473 if (translate_libcrypto_error(ERR_peek_error()) == 3474 SSH_ERR_KEY_WRONG_PASSPHRASE) 3475 return SSH_ERR_KEY_WRONG_PASSPHRASE; 3476 return translate_libcrypto_error(ERR_peek_last_error()); 3477 } 3478 3479 static int 3480 pem_passphrase_cb(char *buf, int size, int rwflag, void *u) 3481 { 3482 char *p = (char *)u; 3483 size_t len; 3484 3485 if (p == NULL || (len = strlen(p)) == 0) 3486 return -1; 3487 if (size < 0 || len > (size_t)size) 3488 return -1; 3489 memcpy(buf, p, len); 3490 return (int)len; 3491 } 3492 3493 static int 3494 sshkey_parse_private_pem_fileblob(struct sshbuf *blob, int type, 3495 const char *passphrase, struct sshkey **keyp) 3496 { 3497 EVP_PKEY *pk = NULL; 3498 struct sshkey *prv = NULL; 3499 BIO *bio = NULL; 3500 int r; 3501 RSA *rsa = NULL; 3502 EC_KEY *ecdsa = NULL; 3503 3504 if (keyp != NULL) 3505 *keyp = NULL; 3506 3507 if ((bio = BIO_new(BIO_s_mem())) == NULL || sshbuf_len(blob) > INT_MAX) 3508 return SSH_ERR_ALLOC_FAIL; 3509 if (BIO_write(bio, sshbuf_ptr(blob), sshbuf_len(blob)) != 3510 (int)sshbuf_len(blob)) { 3511 r = SSH_ERR_ALLOC_FAIL; 3512 goto out; 3513 } 3514 3515 clear_libcrypto_errors(); 3516 if ((pk = PEM_read_bio_PrivateKey(bio, NULL, pem_passphrase_cb, 3517 (char *)passphrase)) == NULL) { 3518 /* 3519 * libcrypto may return various ASN.1 errors when attempting 3520 * to parse a key with an incorrect passphrase. 3521 * Treat all format errors as "incorrect passphrase" if a 3522 * passphrase was supplied. 3523 */ 3524 if (passphrase != NULL && *passphrase != '\0') 3525 r = SSH_ERR_KEY_WRONG_PASSPHRASE; 3526 else 3527 r = convert_libcrypto_error(); 3528 goto out; 3529 } 3530 if (EVP_PKEY_base_id(pk) == EVP_PKEY_RSA && 3531 (type == KEY_UNSPEC || type == KEY_RSA)) { 3532 if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) { 3533 r = SSH_ERR_ALLOC_FAIL; 3534 goto out; 3535 } 3536 if ((rsa = EVP_PKEY_get1_RSA(pk)) == NULL) { 3537 r = SSH_ERR_LIBCRYPTO_ERROR; 3538 goto out; 3539 } 3540 prv->type = KEY_RSA; 3541 #ifdef DEBUG_PK 3542 RSA_print_fp(stderr, rsa, 8); 3543 #endif 3544 if (RSA_blinding_on(rsa, NULL) != 1 || 3545 EVP_PKEY_set1_RSA(pk, rsa) != 1) { 3546 r = SSH_ERR_LIBCRYPTO_ERROR; 3547 goto out; 3548 } 3549 EVP_PKEY_up_ref(pk); 3550 prv->pkey = pk; 3551 if ((r = sshkey_check_rsa_length(prv, 0)) != 0) 3552 goto out; 3553 #ifdef OPENSSL_HAS_ECC 3554 } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_EC && 3555 (type == KEY_UNSPEC || type == KEY_ECDSA)) { 3556 if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) { 3557 r = SSH_ERR_ALLOC_FAIL; 3558 goto out; 3559 } 3560 if ((prv->ecdsa_nid = sshkey_ecdsa_fixup_group(pk)) == -1 || 3561 (ecdsa = EVP_PKEY_get1_EC_KEY(pk)) == NULL) { 3562 r = SSH_ERR_LIBCRYPTO_ERROR; 3563 goto out; 3564 } 3565 prv->type = KEY_ECDSA; 3566 if (sshkey_curve_nid_to_name(prv->ecdsa_nid) == NULL || 3567 sshkey_ec_validate_public(EC_KEY_get0_group(ecdsa), 3568 EC_KEY_get0_public_key(ecdsa)) != 0 || 3569 sshkey_ec_validate_private(ecdsa) != 0) { 3570 r = SSH_ERR_INVALID_FORMAT; 3571 goto out; 3572 } 3573 EVP_PKEY_up_ref(pk); 3574 prv->pkey = pk; 3575 #ifdef DEBUG_PK 3576 if (prv != NULL && prv->pkey != NULL) 3577 sshkey_dump_ec_key(EVP_PKEY_get0_EC_KEY(prv->pkey)); 3578 #endif 3579 #endif /* OPENSSL_HAS_ECC */ 3580 #ifdef OPENSSL_HAS_ED25519 3581 } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_ED25519 && 3582 (type == KEY_UNSPEC || type == KEY_ED25519)) { 3583 size_t len; 3584 3585 if ((prv = sshkey_new(KEY_UNSPEC)) == NULL || 3586 (prv->ed25519_sk = calloc(1, ED25519_SK_SZ)) == NULL || 3587 (prv->ed25519_pk = calloc(1, ED25519_PK_SZ)) == NULL) { 3588 r = SSH_ERR_ALLOC_FAIL; 3589 goto out; 3590 } 3591 prv->type = KEY_ED25519; 3592 len = ED25519_PK_SZ; 3593 if (!EVP_PKEY_get_raw_public_key(pk, prv->ed25519_pk, &len)) { 3594 r = SSH_ERR_LIBCRYPTO_ERROR; 3595 goto out; 3596 } 3597 if (len != ED25519_PK_SZ) { 3598 r = SSH_ERR_INVALID_FORMAT; 3599 goto out; 3600 } 3601 len = ED25519_SK_SZ - ED25519_PK_SZ; 3602 if (!EVP_PKEY_get_raw_private_key(pk, prv->ed25519_sk, &len)) { 3603 r = SSH_ERR_LIBCRYPTO_ERROR; 3604 goto out; 3605 } 3606 if (len != ED25519_SK_SZ - ED25519_PK_SZ) { 3607 r = SSH_ERR_INVALID_FORMAT; 3608 goto out; 3609 } 3610 /* Append the public key to our private key */ 3611 memcpy(prv->ed25519_sk + (ED25519_SK_SZ - ED25519_PK_SZ), 3612 prv->ed25519_pk, ED25519_PK_SZ); 3613 #ifdef DEBUG_PK 3614 sshbuf_dump_data(prv->ed25519_sk, ED25519_SK_SZ, stderr); 3615 #endif 3616 #endif /* OPENSSL_HAS_ED25519 */ 3617 } else { 3618 r = SSH_ERR_INVALID_FORMAT; 3619 goto out; 3620 } 3621 r = 0; 3622 if (keyp != NULL) { 3623 *keyp = prv; 3624 prv = NULL; 3625 } 3626 out: 3627 BIO_free(bio); 3628 EVP_PKEY_free(pk); 3629 RSA_free(rsa); 3630 #ifdef OPENSSL_HAS_ECC 3631 EC_KEY_free(ecdsa); 3632 #endif 3633 sshkey_free(prv); 3634 return r; 3635 } 3636 #endif /* WITH_OPENSSL */ 3637 3638 int 3639 sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type, 3640 const char *passphrase, struct sshkey **keyp, char **commentp) 3641 { 3642 int r = SSH_ERR_INTERNAL_ERROR; 3643 3644 if (keyp != NULL) 3645 *keyp = NULL; 3646 if (commentp != NULL) 3647 *commentp = NULL; 3648 3649 r = sshkey_parse_private2(blob, type, passphrase, keyp, commentp); 3650 /* Only fallback to PEM parser if a format error occurred. */ 3651 if (r != SSH_ERR_INVALID_FORMAT) 3652 return r; 3653 #ifdef WITH_OPENSSL 3654 return sshkey_parse_private_pem_fileblob(blob, type, 3655 passphrase, keyp); 3656 #else 3657 return SSH_ERR_INVALID_FORMAT; 3658 #endif /* WITH_OPENSSL */ 3659 } 3660 3661 int 3662 sshkey_parse_private_fileblob(struct sshbuf *buffer, const char *passphrase, 3663 struct sshkey **keyp, char **commentp) 3664 { 3665 if (keyp != NULL) 3666 *keyp = NULL; 3667 if (commentp != NULL) 3668 *commentp = NULL; 3669 3670 return sshkey_parse_private_fileblob_type(buffer, KEY_UNSPEC, 3671 passphrase, keyp, commentp); 3672 } 3673 3674 void 3675 sshkey_sig_details_free(struct sshkey_sig_details *details) 3676 { 3677 freezero(details, sizeof(*details)); 3678 } 3679 3680 int 3681 sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob, int type, 3682 struct sshkey **pubkeyp) 3683 { 3684 int r = SSH_ERR_INTERNAL_ERROR; 3685 3686 if (pubkeyp != NULL) 3687 *pubkeyp = NULL; 3688 /* only new-format private keys bundle a public key inside */ 3689 if ((r = sshkey_parse_private2_pubkey(blob, type, pubkeyp)) != 0) 3690 return r; 3691 return 0; 3692 } 3693