1 /* $OpenBSD: sshkey.c,v 1.163 2026/06/29 01:58:29 djm Exp $ */ 2 /* 3 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 4 * Copyright (c) 2008 Alexander von Gernler. All rights reserved. 5 * Copyright (c) 2010,2011 Damien Miller. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include "includes.h" 29 30 #include <sys/types.h> 31 #include <sys/mman.h> 32 #include <netinet/in.h> 33 34 #ifdef WITH_OPENSSL 35 #include <openssl/bn.h> 36 #include <openssl/evp.h> 37 #include <openssl/err.h> 38 #include <openssl/pem.h> 39 #endif 40 41 #include "crypto_api.h" 42 43 #include <errno.h> 44 #include <limits.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <resolv.h> 49 #include <time.h> 50 #include <util.h> 51 52 #include "ssh2.h" 53 #include "ssherr.h" 54 #include "misc.h" 55 #include "sshbuf.h" 56 #include "cipher.h" 57 #include "digest.h" 58 #define SSHKEY_INTERNAL 59 #include "sshkey.h" 60 #include "match.h" 61 #include "ssh-sk.h" 62 #include "ssh-pkcs11.h" 63 64 #include "openbsd-compat/openssl-compat.h" 65 66 /* openssh private key file format */ 67 #define MARK_BEGIN "-----BEGIN OPENSSH PRIVATE KEY-----\n" 68 #define MARK_END "-----END OPENSSH PRIVATE KEY-----\n" 69 #define MARK_BEGIN_LEN (sizeof(MARK_BEGIN) - 1) 70 #define MARK_END_LEN (sizeof(MARK_END) - 1) 71 #define KDFNAME "bcrypt" 72 #define AUTH_MAGIC "openssh-key-v1" 73 #define SALT_LEN 16 74 #define DEFAULT_CIPHERNAME "aes256-ctr" 75 #define DEFAULT_ROUNDS 24 76 77 /* 78 * Constants relating to "shielding" support; protection of keys expected 79 * to remain in memory for long durations 80 */ 81 #define SSHKEY_SHIELD_PREKEY_LEN (16 * 1024) 82 #define SSHKEY_SHIELD_CIPHER "aes256-ctr" /* XXX want AES-EME* */ 83 #define SSHKEY_SHIELD_PREKEY_HASH SSH_DIGEST_SHA512 84 85 static int sshkey_from_blob_internal(struct sshbuf *buf, 86 struct sshkey **keyp, int allow_cert); 87 88 /* Supported key types */ 89 extern const struct sshkey_impl sshkey_ed25519_impl; 90 extern const struct sshkey_impl sshkey_ed25519_cert_impl; 91 extern const struct sshkey_impl sshkey_ed25519_sk_impl; 92 extern const struct sshkey_impl sshkey_ed25519_sk_cert_impl; 93 #ifdef USE_MLDSA 94 extern const struct sshkey_impl sshkey_mldsa44_ed25519_impl; 95 extern const struct sshkey_impl sshkey_mldsa44_ed25519_cert_impl; 96 #endif /* USE_MLDSA */ 97 #ifdef WITH_OPENSSL 98 # ifdef OPENSSL_HAS_ECC 99 # ifdef ENABLE_SK 100 extern const struct sshkey_impl sshkey_ecdsa_sk_impl; 101 extern const struct sshkey_impl sshkey_ecdsa_sk_cert_impl; 102 extern const struct sshkey_impl sshkey_ecdsa_sk_webauthn_impl; 103 extern const struct sshkey_impl sshkey_ecdsa_sk_webauthn_cert_impl; 104 # endif /* ENABLE_SK */ 105 extern const struct sshkey_impl sshkey_ecdsa_nistp256_impl; 106 extern const struct sshkey_impl sshkey_ecdsa_nistp256_cert_impl; 107 extern const struct sshkey_impl sshkey_ecdsa_nistp384_impl; 108 extern const struct sshkey_impl sshkey_ecdsa_nistp384_cert_impl; 109 # ifdef OPENSSL_HAS_NISTP521 110 extern const struct sshkey_impl sshkey_ecdsa_nistp521_impl; 111 extern const struct sshkey_impl sshkey_ecdsa_nistp521_cert_impl; 112 # endif /* OPENSSL_HAS_NISTP521 */ 113 # endif /* OPENSSL_HAS_ECC */ 114 extern const struct sshkey_impl sshkey_rsa_impl; 115 extern const struct sshkey_impl sshkey_rsa_cert_impl; 116 extern const struct sshkey_impl sshkey_rsa_sha256_impl; 117 extern const struct sshkey_impl sshkey_rsa_sha256_cert_impl; 118 extern const struct sshkey_impl sshkey_rsa_sha512_impl; 119 extern const struct sshkey_impl sshkey_rsa_sha512_cert_impl; 120 #endif /* WITH_OPENSSL */ 121 122 const struct sshkey_impl * const keyimpls[] = { 123 &sshkey_ed25519_impl, 124 &sshkey_ed25519_cert_impl, 125 #ifdef ENABLE_SK 126 &sshkey_ed25519_sk_impl, 127 &sshkey_ed25519_sk_cert_impl, 128 #endif 129 #ifdef USE_MLDSA 130 &sshkey_mldsa44_ed25519_impl, 131 &sshkey_mldsa44_ed25519_cert_impl, 132 #endif /* USE_MLDSA */ 133 #ifdef WITH_OPENSSL 134 # ifdef OPENSSL_HAS_ECC 135 &sshkey_ecdsa_nistp256_impl, 136 &sshkey_ecdsa_nistp256_cert_impl, 137 &sshkey_ecdsa_nistp384_impl, 138 &sshkey_ecdsa_nistp384_cert_impl, 139 # ifdef OPENSSL_HAS_NISTP521 140 &sshkey_ecdsa_nistp521_impl, 141 &sshkey_ecdsa_nistp521_cert_impl, 142 # endif /* OPENSSL_HAS_NISTP521 */ 143 # ifdef ENABLE_SK 144 &sshkey_ecdsa_sk_impl, 145 &sshkey_ecdsa_sk_cert_impl, 146 &sshkey_ecdsa_sk_webauthn_impl, 147 &sshkey_ecdsa_sk_webauthn_cert_impl, 148 # endif /* ENABLE_SK */ 149 # endif /* OPENSSL_HAS_ECC */ 150 &sshkey_rsa_impl, 151 &sshkey_rsa_cert_impl, 152 &sshkey_rsa_sha256_impl, 153 &sshkey_rsa_sha256_cert_impl, 154 &sshkey_rsa_sha512_impl, 155 &sshkey_rsa_sha512_cert_impl, 156 #endif /* WITH_OPENSSL */ 157 NULL 158 }; 159 160 static const struct sshkey_impl * 161 sshkey_impl_from_type(int type) 162 { 163 int i; 164 165 for (i = 0; keyimpls[i] != NULL; i++) { 166 if (keyimpls[i]->type == type) 167 return keyimpls[i]; 168 } 169 return NULL; 170 } 171 172 static const struct sshkey_impl * 173 sshkey_impl_from_type_nid(int type, int nid) 174 { 175 int i; 176 177 for (i = 0; keyimpls[i] != NULL; i++) { 178 if (keyimpls[i]->type == type && 179 (keyimpls[i]->nid == 0 || keyimpls[i]->nid == nid)) 180 return keyimpls[i]; 181 } 182 return NULL; 183 } 184 185 static const struct sshkey_impl * 186 sshkey_impl_from_key(const struct sshkey *k) 187 { 188 if (k == NULL) 189 return NULL; 190 return sshkey_impl_from_type_nid(k->type, k->ecdsa_nid); 191 } 192 193 const char * 194 sshkey_type(const struct sshkey *k) 195 { 196 const struct sshkey_impl *impl; 197 198 if ((impl = sshkey_impl_from_key(k)) == NULL) 199 return "unknown"; 200 return impl->shortname; 201 } 202 203 static const char * 204 sshkey_ssh_name_from_type_nid(int type, int nid) 205 { 206 const struct sshkey_impl *impl; 207 208 if ((impl = sshkey_impl_from_type_nid(type, nid)) == NULL) 209 return "ssh-unknown"; 210 return impl->name; 211 } 212 213 int 214 sshkey_type_is_cert(int type) 215 { 216 const struct sshkey_impl *impl; 217 218 if ((impl = sshkey_impl_from_type(type)) == NULL) 219 return 0; 220 return impl->cert; 221 } 222 223 const char * 224 sshkey_ssh_name(const struct sshkey *k) 225 { 226 return sshkey_ssh_name_from_type_nid(k->type, k->ecdsa_nid); 227 } 228 229 const char * 230 sshkey_ssh_name_plain(const struct sshkey *k) 231 { 232 return sshkey_ssh_name_from_type_nid(sshkey_type_plain(k->type), 233 k->ecdsa_nid); 234 } 235 236 static int 237 type_from_name(const char *name, int allow_short) 238 { 239 int i; 240 const struct sshkey_impl *impl; 241 242 for (i = 0; keyimpls[i] != NULL; i++) { 243 impl = keyimpls[i]; 244 if (impl->name != NULL && strcmp(name, impl->name) == 0) 245 return impl->type; 246 /* Only allow shortname matches for plain key types */ 247 if (allow_short && !impl->cert && impl->shortname != NULL && 248 strcasecmp(impl->shortname, name) == 0) 249 return impl->type; 250 } 251 return KEY_UNSPEC; 252 } 253 254 int 255 sshkey_type_from_name(const char *name) 256 { 257 return type_from_name(name, 0); 258 } 259 260 int 261 sshkey_type_from_shortname(const char *name) 262 { 263 return type_from_name(name, 1); 264 } 265 266 static int 267 key_type_is_ecdsa_variant(int type) 268 { 269 switch (type) { 270 case KEY_ECDSA: 271 case KEY_ECDSA_CERT: 272 case KEY_ECDSA_SK: 273 case KEY_ECDSA_SK_CERT: 274 return 1; 275 } 276 return 0; 277 } 278 279 int 280 sshkey_ecdsa_nid_from_name(const char *name) 281 { 282 int i; 283 284 for (i = 0; keyimpls[i] != NULL; i++) { 285 if (!key_type_is_ecdsa_variant(keyimpls[i]->type)) 286 continue; 287 if (keyimpls[i]->name != NULL && 288 strcmp(name, keyimpls[i]->name) == 0) 289 return keyimpls[i]->nid; 290 } 291 return -1; 292 } 293 294 int 295 sshkey_match_keyname_to_sigalgs(const char *keyname, const char *sigalgs) 296 { 297 int ktype; 298 299 if (sigalgs == NULL || *sigalgs == '\0' || 300 (ktype = sshkey_type_from_name(keyname)) == KEY_UNSPEC) 301 return 0; 302 else if (ktype == KEY_RSA) { 303 return match_pattern_list("ssh-rsa", sigalgs, 0) == 1 || 304 match_pattern_list("rsa-sha2-256", sigalgs, 0) == 1 || 305 match_pattern_list("rsa-sha2-512", sigalgs, 0) == 1; 306 } else if (ktype == KEY_RSA_CERT) { 307 return match_pattern_list("ssh-rsa-cert-v01@openssh.com", 308 sigalgs, 0) == 1 || 309 match_pattern_list("rsa-sha2-256-cert-v01@openssh.com", 310 sigalgs, 0) == 1 || 311 match_pattern_list("rsa-sha2-512-cert-v01@openssh.com", 312 sigalgs, 0) == 1; 313 } else if (ktype == KEY_ECDSA_SK) { 314 return match_pattern_list("sk-ecdsa-sha2-nistp256@openssh.com", 315 sigalgs, 0) == 1 || match_pattern_list( 316 "webauthn-sk-ecdsa-sha2-nistp256@openssh.com", 317 sigalgs, 0) == 1; 318 } else if (ktype == KEY_ECDSA_SK_CERT) { 319 return match_pattern_list( 320 "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com", 321 sigalgs, 0) == 1 || match_pattern_list( 322 "webauthn-sk-ecdsa-sha2-nistp256-cert-v01@openssh.com", 323 sigalgs, 0) == 1; 324 } else 325 return match_pattern_list(keyname, sigalgs, 0) == 1; 326 } 327 328 char * 329 sshkey_alg_list(int certs_only, int plain_only, int include_sigonly, char sep) 330 { 331 char *ret = NULL; 332 size_t i; 333 const struct sshkey_impl *impl; 334 char sep_str[2] = {sep, '\0'}; 335 336 for (i = 0; keyimpls[i] != NULL; i++) { 337 impl = keyimpls[i]; 338 if (impl->name == NULL) 339 continue; 340 if (!include_sigonly && impl->sigonly) 341 continue; 342 if ((certs_only && !impl->cert) || (plain_only && impl->cert)) 343 continue; 344 xextendf(&ret, sep_str, "%s", impl->name); 345 } 346 return ret; 347 } 348 349 int 350 sshkey_names_valid2(const char *names, int allow_wildcard, int plain_only) 351 { 352 char *s, *cp, *p; 353 const struct sshkey_impl *impl; 354 int i, type; 355 356 if (names == NULL || strcmp(names, "") == 0) 357 return 0; 358 if ((s = cp = strdup(names)) == NULL) 359 return 0; 360 for ((p = strsep(&cp, ",")); p && *p != '\0'; 361 (p = strsep(&cp, ","))) { 362 type = sshkey_type_from_name(p); 363 if (type == KEY_UNSPEC) { 364 if (allow_wildcard) { 365 /* 366 * Try matching key types against the string. 367 * If any has a positive or negative match then 368 * the component is accepted. 369 */ 370 impl = NULL; 371 for (i = 0; keyimpls[i] != NULL; i++) { 372 if (match_pattern_list( 373 keyimpls[i]->name, p, 0) != 0) { 374 impl = keyimpls[i]; 375 break; 376 } 377 } 378 if (impl != NULL) 379 continue; 380 } 381 free(s); 382 return 0; 383 } else if (plain_only && sshkey_type_is_cert(type)) { 384 free(s); 385 return 0; 386 } 387 } 388 free(s); 389 return 1; 390 } 391 392 u_int 393 sshkey_size(const struct sshkey *k) 394 { 395 const struct sshkey_impl *impl; 396 397 if ((impl = sshkey_impl_from_key(k)) == NULL) 398 return 0; 399 if (impl->funcs->size != NULL) 400 return impl->funcs->size(k); 401 return impl->keybits; 402 } 403 404 static int 405 sshkey_type_is_valid_ca(int type) 406 { 407 const struct sshkey_impl *impl; 408 409 if ((impl = sshkey_impl_from_type(type)) == NULL) 410 return 0; 411 /* All non-certificate types may act as CAs */ 412 return !impl->cert; 413 } 414 415 int 416 sshkey_is_cert(const struct sshkey *k) 417 { 418 if (k == NULL) 419 return 0; 420 return sshkey_type_is_cert(k->type); 421 } 422 423 int 424 sshkey_is_sk(const struct sshkey *k) 425 { 426 if (k == NULL) 427 return 0; 428 switch (sshkey_type_plain(k->type)) { 429 case KEY_ECDSA_SK: 430 case KEY_ED25519_SK: 431 return 1; 432 default: 433 return 0; 434 } 435 } 436 437 /* Return the cert-less equivalent to a certified key type */ 438 int 439 sshkey_type_plain(int type) 440 { 441 switch (type) { 442 case KEY_RSA_CERT: 443 return KEY_RSA; 444 case KEY_ECDSA_CERT: 445 return KEY_ECDSA; 446 case KEY_ECDSA_SK_CERT: 447 return KEY_ECDSA_SK; 448 case KEY_ED25519_CERT: 449 return KEY_ED25519; 450 case KEY_MLDSA44_ED25519_CERT: 451 return KEY_MLDSA44_ED25519; 452 case KEY_ED25519_SK_CERT: 453 return KEY_ED25519_SK; 454 default: 455 return type; 456 } 457 } 458 459 /* Return the cert equivalent to a plain key type */ 460 static int 461 sshkey_type_certified(int type) 462 { 463 switch (type) { 464 case KEY_RSA: 465 return KEY_RSA_CERT; 466 case KEY_ECDSA: 467 return KEY_ECDSA_CERT; 468 case KEY_ECDSA_SK: 469 return KEY_ECDSA_SK_CERT; 470 case KEY_ED25519: 471 return KEY_ED25519_CERT; 472 case KEY_MLDSA44_ED25519: 473 return KEY_MLDSA44_ED25519_CERT; 474 case KEY_ED25519_SK: 475 return KEY_ED25519_SK_CERT; 476 default: 477 return -1; 478 } 479 } 480 481 #ifdef WITH_OPENSSL 482 static const EVP_MD * 483 ssh_digest_to_md(int hash_alg) 484 { 485 switch (hash_alg) { 486 case SSH_DIGEST_SHA1: 487 return EVP_sha1(); 488 case SSH_DIGEST_SHA256: 489 return EVP_sha256(); 490 case SSH_DIGEST_SHA384: 491 return EVP_sha384(); 492 case SSH_DIGEST_SHA512: 493 return EVP_sha512(); 494 } 495 return NULL; 496 } 497 498 int 499 sshkey_pkey_digest_sign(EVP_PKEY *pkey, int hash_alg, u_char **sigp, 500 size_t *lenp, const u_char *data, size_t datalen) 501 { 502 EVP_MD_CTX *ctx = NULL; 503 u_char *sig = NULL; 504 int ret; 505 size_t slen; 506 const EVP_MD *evpmd; 507 508 *sigp = NULL; 509 *lenp = 0; 510 511 slen = EVP_PKEY_size(pkey); 512 if (slen <= 0 || slen > SSHBUF_MAX_BIGNUM || 513 (evpmd = ssh_digest_to_md(hash_alg)) == NULL) 514 return SSH_ERR_INVALID_ARGUMENT; 515 516 if ((sig = malloc(slen)) == NULL) 517 return SSH_ERR_ALLOC_FAIL; 518 519 if ((ctx = EVP_MD_CTX_new()) == NULL) { 520 ret = SSH_ERR_ALLOC_FAIL; 521 goto out; 522 } 523 if (EVP_DigestSignInit(ctx, NULL, evpmd, NULL, pkey) != 1 || 524 EVP_DigestSign(ctx, sig, &slen, data, datalen) != 1) { 525 ret = SSH_ERR_LIBCRYPTO_ERROR; 526 goto out; 527 } 528 529 *sigp = sig; 530 *lenp = slen; 531 /* Now owned by the caller */ 532 sig = NULL; 533 ret = 0; 534 535 out: 536 EVP_MD_CTX_free(ctx); 537 free(sig); 538 return ret; 539 } 540 541 int 542 sshkey_pkey_digest_verify(EVP_PKEY *pkey, int hash_alg, const u_char *data, 543 size_t datalen, u_char *sigbuf, size_t siglen) 544 { 545 EVP_MD_CTX *ctx = NULL; 546 int ret = SSH_ERR_INTERNAL_ERROR; 547 const EVP_MD *evpmd; 548 549 if ((evpmd = ssh_digest_to_md(hash_alg)) == NULL) 550 return SSH_ERR_INVALID_ARGUMENT; 551 if ((ctx = EVP_MD_CTX_new()) == NULL) 552 return SSH_ERR_ALLOC_FAIL; 553 if (EVP_DigestVerifyInit(ctx, NULL, evpmd, NULL, pkey) != 1) { 554 ret = SSH_ERR_LIBCRYPTO_ERROR; 555 goto out; 556 } 557 switch (EVP_DigestVerify(ctx, sigbuf, siglen, data, datalen)) { 558 case 1: 559 ret = 0; 560 break; 561 case 0: 562 ret = SSH_ERR_SIGNATURE_INVALID; 563 break; 564 default: 565 ret = SSH_ERR_LIBCRYPTO_ERROR; 566 break; 567 } 568 569 out: 570 EVP_MD_CTX_free(ctx); 571 return ret; 572 } 573 574 /* XXX: these are really begging for a table-driven approach */ 575 int 576 sshkey_curve_name_to_nid(const char *name) 577 { 578 if (strcmp(name, "nistp256") == 0) 579 return NID_X9_62_prime256v1; 580 else if (strcmp(name, "nistp384") == 0) 581 return NID_secp384r1; 582 # ifdef OPENSSL_HAS_NISTP521 583 else if (strcmp(name, "nistp521") == 0) 584 return NID_secp521r1; 585 # endif /* OPENSSL_HAS_NISTP521 */ 586 else 587 return -1; 588 } 589 590 u_int 591 sshkey_curve_nid_to_bits(int nid) 592 { 593 switch (nid) { 594 case NID_X9_62_prime256v1: 595 return 256; 596 case NID_secp384r1: 597 return 384; 598 # ifdef OPENSSL_HAS_NISTP521 599 case NID_secp521r1: 600 return 521; 601 # endif /* OPENSSL_HAS_NISTP521 */ 602 default: 603 return 0; 604 } 605 } 606 607 int 608 sshkey_ecdsa_bits_to_nid(int bits) 609 { 610 switch (bits) { 611 case 256: 612 return NID_X9_62_prime256v1; 613 case 384: 614 return NID_secp384r1; 615 # ifdef OPENSSL_HAS_NISTP521 616 case 521: 617 return NID_secp521r1; 618 # endif /* OPENSSL_HAS_NISTP521 */ 619 default: 620 return -1; 621 } 622 } 623 624 const char * 625 sshkey_curve_nid_to_name(int nid) 626 { 627 switch (nid) { 628 case NID_X9_62_prime256v1: 629 return "nistp256"; 630 case NID_secp384r1: 631 return "nistp384"; 632 # ifdef OPENSSL_HAS_NISTP521 633 case NID_secp521r1: 634 return "nistp521"; 635 # endif /* OPENSSL_HAS_NISTP521 */ 636 default: 637 return NULL; 638 } 639 } 640 641 int 642 sshkey_ec_nid_to_hash_alg(int nid) 643 { 644 int kbits = sshkey_curve_nid_to_bits(nid); 645 646 if (kbits <= 0) 647 return -1; 648 649 /* RFC5656 section 6.2.1 */ 650 if (kbits <= 256) 651 return SSH_DIGEST_SHA256; 652 else if (kbits <= 384) 653 return SSH_DIGEST_SHA384; 654 else 655 return SSH_DIGEST_SHA512; 656 } 657 #endif /* WITH_OPENSSL */ 658 659 static void 660 cert_free(struct sshkey_cert *cert) 661 { 662 u_int i; 663 664 if (cert == NULL) 665 return; 666 sshbuf_free(cert->certblob); 667 sshbuf_free(cert->critical); 668 sshbuf_free(cert->extensions); 669 free(cert->key_id); 670 for (i = 0; i < cert->nprincipals; i++) 671 free(cert->principals[i]); 672 free(cert->principals); 673 sshkey_free(cert->signature_key); 674 free(cert->signature_type); 675 freezero(cert, sizeof(*cert)); 676 } 677 678 static struct sshkey_cert * 679 cert_new(void) 680 { 681 struct sshkey_cert *cert; 682 683 if ((cert = calloc(1, sizeof(*cert))) == NULL) 684 return NULL; 685 if ((cert->certblob = sshbuf_new()) == NULL || 686 (cert->critical = sshbuf_new()) == NULL || 687 (cert->extensions = sshbuf_new()) == NULL) { 688 cert_free(cert); 689 return NULL; 690 } 691 cert->key_id = NULL; 692 cert->principals = NULL; 693 cert->signature_key = NULL; 694 cert->signature_type = NULL; 695 return cert; 696 } 697 698 struct sshkey * 699 sshkey_new(int type) 700 { 701 struct sshkey *k; 702 const struct sshkey_impl *impl = NULL; 703 704 if (type != KEY_UNSPEC && 705 (impl = sshkey_impl_from_type(type)) == NULL) 706 return NULL; 707 708 /* All non-certificate types may act as CAs */ 709 if ((k = calloc(1, sizeof(*k))) == NULL) 710 return NULL; 711 k->type = type; 712 k->ecdsa_nid = -1; 713 if (impl != NULL && impl->funcs->alloc != NULL) { 714 if (impl->funcs->alloc(k) != 0) { 715 free(k); 716 return NULL; 717 } 718 } 719 if (sshkey_is_cert(k)) { 720 if ((k->cert = cert_new()) == NULL) { 721 sshkey_free(k); 722 return NULL; 723 } 724 } 725 726 return k; 727 } 728 729 /* Frees common FIDO fields */ 730 void 731 sshkey_sk_cleanup(struct sshkey *k) 732 { 733 free(k->sk_application); 734 sshbuf_free(k->sk_key_handle); 735 sshbuf_free(k->sk_reserved); 736 k->sk_application = NULL; 737 k->sk_key_handle = k->sk_reserved = NULL; 738 } 739 740 #if defined(MAP_CONCEAL) 741 # define PREKEY_MMAP_FLAG MAP_CONCEAL 742 #elif defined(MAP_NOCORE) 743 # define PREKEY_MMAP_FLAG MAP_NOCORE 744 #else 745 # define PREKEY_MMAP_FLAG 0 746 #endif 747 748 static int 749 sshkey_prekey_alloc(u_char **prekeyp, size_t len) 750 { 751 #if defined(HAVE_MMAP) && defined(MAP_ANON) && defined(MAP_PRIVATE) 752 u_char *prekey; 753 754 *prekeyp = NULL; 755 if ((prekey = mmap(NULL, len, PROT_READ|PROT_WRITE, 756 MAP_ANON|MAP_PRIVATE|PREKEY_MMAP_FLAG, -1, 0)) == MAP_FAILED) 757 return SSH_ERR_SYSTEM_ERROR; 758 #if defined(MADV_DONTDUMP) && !defined(MAP_CONCEAL) && !defined(MAP_NOCORE) 759 (void)madvise(prekey, len, MADV_DONTDUMP); 760 #endif 761 *prekeyp = prekey; 762 #else 763 *prekeyp = calloc(1, len); 764 #endif /* HAVE_MMAP et al */ 765 return 0; 766 } 767 768 static void 769 sshkey_prekey_free(void *prekey, size_t len) 770 { 771 #if defined(HAVE_MMAP) && defined(MAP_ANON) && defined(MAP_PRIVATE) 772 if (prekey == NULL) 773 return; 774 munmap(prekey, len); 775 #else 776 free(prekey); 777 #endif /* HAVE_MMAP et al */ 778 } 779 780 static void 781 sshkey_free_contents(struct sshkey *k) 782 { 783 const struct sshkey_impl *impl; 784 785 if (k == NULL) 786 return; 787 if ((k->flags & SSHKEY_FLAG_EXT) != 0) 788 pkcs11_key_free(k); 789 if ((impl = sshkey_impl_from_type(k->type)) != NULL && 790 impl->funcs->cleanup != NULL) 791 impl->funcs->cleanup(k); 792 if (sshkey_is_cert(k)) 793 cert_free(k->cert); 794 freezero(k->shielded_private, k->shielded_len); 795 sshkey_prekey_free(k->shield_prekey, k->shield_prekey_len); 796 } 797 798 void 799 sshkey_free(struct sshkey *k) 800 { 801 sshkey_free_contents(k); 802 freezero(k, sizeof(*k)); 803 } 804 805 static int 806 cert_compare(struct sshkey_cert *a, struct sshkey_cert *b) 807 { 808 if (a == NULL && b == NULL) 809 return 1; 810 if (a == NULL || b == NULL) 811 return 0; 812 if (sshbuf_len(a->certblob) != sshbuf_len(b->certblob)) 813 return 0; 814 if (timingsafe_bcmp(sshbuf_ptr(a->certblob), sshbuf_ptr(b->certblob), 815 sshbuf_len(a->certblob)) != 0) 816 return 0; 817 return 1; 818 } 819 820 /* Compares FIDO-specific pubkey fields only */ 821 int 822 sshkey_sk_fields_equal(const struct sshkey *a, const struct sshkey *b) 823 { 824 if (a->sk_application == NULL || b->sk_application == NULL) 825 return 0; 826 if (strcmp(a->sk_application, b->sk_application) != 0) 827 return 0; 828 return 1; 829 } 830 831 /* 832 * Compare public portions of key only, allowing comparisons between 833 * certificates and plain keys too. 834 */ 835 int 836 sshkey_equal_public(const struct sshkey *a, const struct sshkey *b) 837 { 838 const struct sshkey_impl *impl; 839 840 if (a == NULL || b == NULL || 841 sshkey_type_plain(a->type) != sshkey_type_plain(b->type)) 842 return 0; 843 if ((impl = sshkey_impl_from_type(a->type)) == NULL) 844 return 0; 845 return impl->funcs->equal(a, b); 846 } 847 848 int 849 sshkey_equal(const struct sshkey *a, const struct sshkey *b) 850 { 851 if (a == NULL || b == NULL || a->type != b->type) 852 return 0; 853 if (sshkey_is_cert(a)) { 854 if (!cert_compare(a->cert, b->cert)) 855 return 0; 856 } 857 return sshkey_equal_public(a, b); 858 } 859 860 861 /* Serialise common FIDO key parts */ 862 int 863 sshkey_serialize_sk(const struct sshkey *key, struct sshbuf *b) 864 { 865 int r; 866 867 if ((r = sshbuf_put_cstring(b, key->sk_application)) != 0) 868 return r; 869 870 return 0; 871 } 872 873 static int 874 to_blob_buf(const struct sshkey *key, struct sshbuf *b, int force_plain, 875 enum sshkey_serialize_rep opts) 876 { 877 int type, ret = SSH_ERR_INTERNAL_ERROR; 878 const char *typename; 879 const struct sshkey_impl *impl; 880 881 if (key == NULL) 882 return SSH_ERR_INVALID_ARGUMENT; 883 884 type = force_plain ? sshkey_type_plain(key->type) : key->type; 885 886 if (sshkey_type_is_cert(type)) { 887 if (key->cert == NULL) 888 return SSH_ERR_EXPECTED_CERT; 889 if (sshbuf_len(key->cert->certblob) == 0) 890 return SSH_ERR_KEY_LACKS_CERTBLOB; 891 /* Use the existing blob */ 892 if ((ret = sshbuf_putb(b, key->cert->certblob)) != 0) 893 return ret; 894 return 0; 895 } 896 if ((impl = sshkey_impl_from_type(type)) == NULL) 897 return SSH_ERR_KEY_TYPE_UNKNOWN; 898 899 typename = sshkey_ssh_name_from_type_nid(type, key->ecdsa_nid); 900 if ((ret = sshbuf_put_cstring(b, typename)) != 0) 901 return ret; 902 return impl->funcs->serialize_public(key, b, opts); 903 } 904 905 int 906 sshkey_putb(const struct sshkey *key, struct sshbuf *b) 907 { 908 return to_blob_buf(key, b, 0, SSHKEY_SERIALIZE_DEFAULT); 909 } 910 911 static int 912 sshkey_puts_opts_internal(const struct sshkey *key, struct sshbuf *b, 913 enum sshkey_serialize_rep opts, int force_plain) 914 { 915 struct sshbuf *tmp; 916 int r; 917 918 if ((tmp = sshbuf_new()) == NULL) 919 return SSH_ERR_ALLOC_FAIL; 920 r = to_blob_buf(key, tmp, force_plain, opts); 921 if (r == 0) 922 r = sshbuf_put_stringb(b, tmp); 923 sshbuf_free(tmp); 924 return r; 925 } 926 927 int 928 sshkey_puts(const struct sshkey *key, struct sshbuf *b) 929 { 930 return sshkey_puts_opts_internal(key, b, SSHKEY_SERIALIZE_DEFAULT, 0); 931 } 932 933 int 934 sshkey_putb_plain(const struct sshkey *key, struct sshbuf *b) 935 { 936 return to_blob_buf(key, b, 1, SSHKEY_SERIALIZE_DEFAULT); 937 } 938 939 int 940 sshkey_puts_plain(const struct sshkey *key, struct sshbuf *b) 941 { 942 return sshkey_puts_opts_internal(key, b, SSHKEY_SERIALIZE_DEFAULT, 1); 943 } 944 945 static int 946 to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp, int force_plain, 947 enum sshkey_serialize_rep opts) 948 { 949 int ret = SSH_ERR_INTERNAL_ERROR; 950 size_t len; 951 struct sshbuf *b = NULL; 952 953 if (lenp != NULL) 954 *lenp = 0; 955 if (blobp != NULL) 956 *blobp = NULL; 957 if ((b = sshbuf_new()) == NULL) 958 return SSH_ERR_ALLOC_FAIL; 959 if ((ret = to_blob_buf(key, b, force_plain, opts)) != 0) 960 goto out; 961 len = sshbuf_len(b); 962 if (lenp != NULL) 963 *lenp = len; 964 if (blobp != NULL) { 965 if ((*blobp = malloc(len)) == NULL) { 966 ret = SSH_ERR_ALLOC_FAIL; 967 goto out; 968 } 969 memcpy(*blobp, sshbuf_ptr(b), len); 970 } 971 ret = 0; 972 out: 973 sshbuf_free(b); 974 return ret; 975 } 976 977 int 978 sshkey_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp) 979 { 980 return to_blob(key, blobp, lenp, 0, SSHKEY_SERIALIZE_DEFAULT); 981 } 982 983 int 984 sshkey_plain_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp) 985 { 986 return to_blob(key, blobp, lenp, 1, SSHKEY_SERIALIZE_DEFAULT); 987 } 988 989 int 990 sshkey_fingerprint_raw(const struct sshkey *k, int dgst_alg, 991 u_char **retp, size_t *lenp) 992 { 993 u_char *blob = NULL, *ret = NULL; 994 size_t blob_len = 0; 995 int r = SSH_ERR_INTERNAL_ERROR; 996 997 if (retp != NULL) 998 *retp = NULL; 999 if (lenp != NULL) 1000 *lenp = 0; 1001 if (ssh_digest_bytes(dgst_alg) == 0) { 1002 r = SSH_ERR_INVALID_ARGUMENT; 1003 goto out; 1004 } 1005 if ((r = to_blob(k, &blob, &blob_len, 1, SSHKEY_SERIALIZE_DEFAULT)) 1006 != 0) 1007 goto out; 1008 if ((ret = calloc(1, SSH_DIGEST_MAX_LENGTH)) == NULL) { 1009 r = SSH_ERR_ALLOC_FAIL; 1010 goto out; 1011 } 1012 if ((r = ssh_digest_memory(dgst_alg, blob, blob_len, 1013 ret, SSH_DIGEST_MAX_LENGTH)) != 0) 1014 goto out; 1015 /* success */ 1016 if (retp != NULL) { 1017 *retp = ret; 1018 ret = NULL; 1019 } 1020 if (lenp != NULL) 1021 *lenp = ssh_digest_bytes(dgst_alg); 1022 r = 0; 1023 out: 1024 free(ret); 1025 if (blob != NULL) 1026 freezero(blob, blob_len); 1027 return r; 1028 } 1029 1030 static char * 1031 fingerprint_b64(const char *alg, u_char *dgst_raw, size_t dgst_raw_len) 1032 { 1033 char *ret; 1034 size_t plen = strlen(alg) + 1; 1035 size_t rlen = ((dgst_raw_len + 2) / 3) * 4 + plen + 1; 1036 1037 if (dgst_raw_len > 65536 || (ret = calloc(1, rlen)) == NULL) 1038 return NULL; 1039 strlcpy(ret, alg, rlen); 1040 strlcat(ret, ":", rlen); 1041 if (dgst_raw_len == 0) 1042 return ret; 1043 if (b64_ntop(dgst_raw, dgst_raw_len, ret + plen, rlen - plen) == -1) { 1044 freezero(ret, rlen); 1045 return NULL; 1046 } 1047 /* Trim padding characters from end */ 1048 ret[strcspn(ret, "=")] = '\0'; 1049 return ret; 1050 } 1051 1052 static char * 1053 fingerprint_hex(const char *alg, u_char *dgst_raw, size_t dgst_raw_len) 1054 { 1055 char *retval, hex[5]; 1056 size_t i, rlen = dgst_raw_len * 3 + strlen(alg) + 2; 1057 1058 if (dgst_raw_len > 65536 || (retval = calloc(1, rlen)) == NULL) 1059 return NULL; 1060 strlcpy(retval, alg, rlen); 1061 strlcat(retval, ":", rlen); 1062 for (i = 0; i < dgst_raw_len; i++) { 1063 snprintf(hex, sizeof(hex), "%s%02x", 1064 i > 0 ? ":" : "", dgst_raw[i]); 1065 strlcat(retval, hex, rlen); 1066 } 1067 return retval; 1068 } 1069 1070 static char * 1071 fingerprint_bubblebabble(u_char *dgst_raw, size_t dgst_raw_len) 1072 { 1073 char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' }; 1074 char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm', 1075 'n', 'p', 'r', 's', 't', 'v', 'z', 'x' }; 1076 u_int i, j = 0, rounds, seed = 1; 1077 char *retval; 1078 1079 rounds = (dgst_raw_len / 2) + 1; 1080 if ((retval = calloc(rounds, 6)) == NULL) 1081 return NULL; 1082 retval[j++] = 'x'; 1083 for (i = 0; i < rounds; i++) { 1084 u_int idx0, idx1, idx2, idx3, idx4; 1085 if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) { 1086 idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) + 1087 seed) % 6; 1088 idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15; 1089 idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) + 1090 (seed / 6)) % 6; 1091 retval[j++] = vowels[idx0]; 1092 retval[j++] = consonants[idx1]; 1093 retval[j++] = vowels[idx2]; 1094 if ((i + 1) < rounds) { 1095 idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15; 1096 idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15; 1097 retval[j++] = consonants[idx3]; 1098 retval[j++] = '-'; 1099 retval[j++] = consonants[idx4]; 1100 seed = ((seed * 5) + 1101 ((((u_int)(dgst_raw[2 * i])) * 7) + 1102 ((u_int)(dgst_raw[(2 * i) + 1])))) % 36; 1103 } 1104 } else { 1105 idx0 = seed % 6; 1106 idx1 = 16; 1107 idx2 = seed / 6; 1108 retval[j++] = vowels[idx0]; 1109 retval[j++] = consonants[idx1]; 1110 retval[j++] = vowels[idx2]; 1111 } 1112 } 1113 retval[j++] = 'x'; 1114 retval[j++] = '\0'; 1115 return retval; 1116 } 1117 1118 /* 1119 * Draw an ASCII-Art representing the fingerprint so human brain can 1120 * profit from its built-in pattern recognition ability. 1121 * This technique is called "random art" and can be found in some 1122 * scientific publications like this original paper: 1123 * 1124 * "Hash Visualization: a New Technique to improve Real-World Security", 1125 * Perrig A. and Song D., 1999, International Workshop on Cryptographic 1126 * Techniques and E-Commerce (CrypTEC '99) 1127 * sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf 1128 * 1129 * The subject came up in a talk by Dan Kaminsky, too. 1130 * 1131 * If you see the picture is different, the key is different. 1132 * If the picture looks the same, you still know nothing. 1133 * 1134 * The algorithm used here is a worm crawling over a discrete plane, 1135 * leaving a trace (augmenting the field) everywhere it goes. 1136 * Movement is taken from dgst_raw 2bit-wise. Bumping into walls 1137 * makes the respective movement vector be ignored for this turn. 1138 * Graphs are not unambiguous, because circles in graphs can be 1139 * walked in either direction. 1140 */ 1141 1142 /* 1143 * Field sizes for the random art. Have to be odd, so the starting point 1144 * can be in the exact middle of the picture, and FLDBASE should be >=8 . 1145 * Else pictures would be too dense, and drawing the frame would 1146 * fail, too, because the key type would not fit in anymore. 1147 */ 1148 #define FLDBASE 8 1149 #define FLDSIZE_Y (FLDBASE + 1) 1150 #define FLDSIZE_X (FLDBASE * 2 + 1) 1151 static char * 1152 fingerprint_randomart(const char *alg, u_char *dgst_raw, size_t dgst_raw_len, 1153 const struct sshkey *k) 1154 { 1155 /* 1156 * Chars to be used after each other every time the worm 1157 * intersects with itself. Matter of taste. 1158 */ 1159 char *augmentation_string = " .o+=*BOX@%&#/^SE"; 1160 char *retval, *p, title[FLDSIZE_X], hash[FLDSIZE_X]; 1161 u_char field[FLDSIZE_X][FLDSIZE_Y]; 1162 size_t i, tlen, hlen; 1163 u_int b; 1164 int x, y, r; 1165 size_t len = strlen(augmentation_string) - 1; 1166 1167 if ((retval = calloc((FLDSIZE_X + 3), (FLDSIZE_Y + 2))) == NULL) 1168 return NULL; 1169 1170 /* initialize field */ 1171 memset(field, 0, FLDSIZE_X * FLDSIZE_Y * sizeof(char)); 1172 x = FLDSIZE_X / 2; 1173 y = FLDSIZE_Y / 2; 1174 1175 /* process raw key */ 1176 for (i = 0; i < dgst_raw_len; i++) { 1177 int input; 1178 /* each byte conveys four 2-bit move commands */ 1179 input = dgst_raw[i]; 1180 for (b = 0; b < 4; b++) { 1181 /* evaluate 2 bit, rest is shifted later */ 1182 x += (input & 0x1) ? 1 : -1; 1183 y += (input & 0x2) ? 1 : -1; 1184 1185 /* assure we are still in bounds */ 1186 x = MAXIMUM(x, 0); 1187 y = MAXIMUM(y, 0); 1188 x = MINIMUM(x, FLDSIZE_X - 1); 1189 y = MINIMUM(y, FLDSIZE_Y - 1); 1190 1191 /* augment the field */ 1192 if (field[x][y] < len - 2) 1193 field[x][y]++; 1194 input = input >> 2; 1195 } 1196 } 1197 1198 /* mark starting point and end point*/ 1199 field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = len - 1; 1200 field[x][y] = len; 1201 1202 /* assemble title */ 1203 r = snprintf(title, sizeof(title), "[%s %u]", 1204 sshkey_type(k), sshkey_size(k)); 1205 /* If [type size] won't fit, then try [type]; fits "[ED25519-CERT]" */ 1206 if (r < 0 || r > (int)sizeof(title)) 1207 r = snprintf(title, sizeof(title), "[%s]", sshkey_type(k)); 1208 tlen = (r <= 0) ? 0 : strlen(title); 1209 1210 /* assemble hash ID. */ 1211 r = snprintf(hash, sizeof(hash), "[%s]", alg); 1212 hlen = (r <= 0) ? 0 : strlen(hash); 1213 1214 /* output upper border */ 1215 p = retval; 1216 *p++ = '+'; 1217 for (i = 0; i < (FLDSIZE_X - tlen) / 2; i++) 1218 *p++ = '-'; 1219 memcpy(p, title, tlen); 1220 p += tlen; 1221 for (i += tlen; i < FLDSIZE_X; i++) 1222 *p++ = '-'; 1223 *p++ = '+'; 1224 *p++ = '\n'; 1225 1226 /* output content */ 1227 for (y = 0; y < FLDSIZE_Y; y++) { 1228 *p++ = '|'; 1229 for (x = 0; x < FLDSIZE_X; x++) 1230 *p++ = augmentation_string[MINIMUM(field[x][y], len)]; 1231 *p++ = '|'; 1232 *p++ = '\n'; 1233 } 1234 1235 /* output lower border */ 1236 *p++ = '+'; 1237 for (i = 0; i < (FLDSIZE_X - hlen) / 2; i++) 1238 *p++ = '-'; 1239 memcpy(p, hash, hlen); 1240 p += hlen; 1241 for (i += hlen; i < FLDSIZE_X; i++) 1242 *p++ = '-'; 1243 *p++ = '+'; 1244 1245 return retval; 1246 } 1247 1248 char * 1249 sshkey_fingerprint(const struct sshkey *k, int dgst_alg, 1250 enum sshkey_fp_rep dgst_rep) 1251 { 1252 char *retval = NULL; 1253 u_char *dgst_raw; 1254 size_t dgst_raw_len; 1255 1256 if (sshkey_fingerprint_raw(k, dgst_alg, &dgst_raw, &dgst_raw_len) != 0) 1257 return NULL; 1258 switch (dgst_rep) { 1259 case SSH_FP_DEFAULT: 1260 if (dgst_alg == SSH_DIGEST_MD5) { 1261 retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg), 1262 dgst_raw, dgst_raw_len); 1263 } else { 1264 retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg), 1265 dgst_raw, dgst_raw_len); 1266 } 1267 break; 1268 case SSH_FP_HEX: 1269 retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg), 1270 dgst_raw, dgst_raw_len); 1271 break; 1272 case SSH_FP_BASE64: 1273 retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg), 1274 dgst_raw, dgst_raw_len); 1275 break; 1276 case SSH_FP_BUBBLEBABBLE: 1277 retval = fingerprint_bubblebabble(dgst_raw, dgst_raw_len); 1278 break; 1279 case SSH_FP_RANDOMART: 1280 retval = fingerprint_randomart(ssh_digest_alg_name(dgst_alg), 1281 dgst_raw, dgst_raw_len, k); 1282 break; 1283 default: 1284 freezero(dgst_raw, dgst_raw_len); 1285 return NULL; 1286 } 1287 freezero(dgst_raw, dgst_raw_len); 1288 return retval; 1289 } 1290 1291 static int 1292 peek_type_nid(const char *s, size_t l, int *nid) 1293 { 1294 const struct sshkey_impl *impl; 1295 int i; 1296 1297 for (i = 0; keyimpls[i] != NULL; i++) { 1298 impl = keyimpls[i]; 1299 if (impl->name == NULL || strlen(impl->name) != l) 1300 continue; 1301 if (memcmp(s, impl->name, l) == 0) { 1302 *nid = -1; 1303 if (key_type_is_ecdsa_variant(impl->type)) 1304 *nid = impl->nid; 1305 return impl->type; 1306 } 1307 } 1308 return KEY_UNSPEC; 1309 } 1310 1311 /* XXX this can now be made const char * */ 1312 int 1313 sshkey_read(struct sshkey *ret, char **cpp) 1314 { 1315 struct sshkey *k; 1316 char *cp, *blobcopy; 1317 size_t space; 1318 int r, type, curve_nid = -1; 1319 struct sshbuf *blob; 1320 1321 if (ret == NULL) 1322 return SSH_ERR_INVALID_ARGUMENT; 1323 if (ret->type != KEY_UNSPEC && sshkey_impl_from_type(ret->type) == NULL) 1324 return SSH_ERR_INVALID_ARGUMENT; 1325 1326 /* Decode type */ 1327 cp = *cpp; 1328 space = strcspn(cp, " \t"); 1329 if (space == strlen(cp)) 1330 return SSH_ERR_INVALID_FORMAT; 1331 if ((type = peek_type_nid(cp, space, &curve_nid)) == KEY_UNSPEC) 1332 return SSH_ERR_INVALID_FORMAT; 1333 1334 /* skip whitespace */ 1335 for (cp += space; *cp == ' ' || *cp == '\t'; cp++) 1336 ; 1337 if (*cp == '\0') 1338 return SSH_ERR_INVALID_FORMAT; 1339 if (ret->type != KEY_UNSPEC && ret->type != type) 1340 return SSH_ERR_KEY_TYPE_MISMATCH; 1341 if ((blob = sshbuf_new()) == NULL) 1342 return SSH_ERR_ALLOC_FAIL; 1343 1344 /* find end of keyblob and decode */ 1345 space = strcspn(cp, " \t"); 1346 if ((blobcopy = strndup(cp, space)) == NULL) { 1347 sshbuf_free(blob); 1348 return SSH_ERR_ALLOC_FAIL; 1349 } 1350 if ((r = sshbuf_b64tod(blob, blobcopy)) != 0) { 1351 free(blobcopy); 1352 sshbuf_free(blob); 1353 return r; 1354 } 1355 free(blobcopy); 1356 if ((r = sshkey_fromb(blob, &k)) != 0) { 1357 sshbuf_free(blob); 1358 return r; 1359 } 1360 sshbuf_free(blob); 1361 1362 /* skip whitespace and leave cp at start of comment */ 1363 for (cp += space; *cp == ' ' || *cp == '\t'; cp++) 1364 ; 1365 1366 /* ensure type of blob matches type at start of line */ 1367 if (k->type != type) { 1368 sshkey_free(k); 1369 return SSH_ERR_KEY_TYPE_MISMATCH; 1370 } 1371 if (key_type_is_ecdsa_variant(type) && curve_nid != k->ecdsa_nid) { 1372 sshkey_free(k); 1373 return SSH_ERR_EC_CURVE_MISMATCH; 1374 } 1375 1376 /* Fill in ret from parsed key */ 1377 sshkey_free_contents(ret); 1378 *ret = *k; 1379 freezero(k, sizeof(*k)); 1380 1381 /* success */ 1382 *cpp = cp; 1383 return 0; 1384 } 1385 1386 int 1387 sshkey_to_base64(const struct sshkey *key, char **b64p) 1388 { 1389 int r = SSH_ERR_INTERNAL_ERROR; 1390 struct sshbuf *b = NULL; 1391 char *uu = NULL; 1392 1393 if (b64p != NULL) 1394 *b64p = NULL; 1395 if ((b = sshbuf_new()) == NULL) 1396 return SSH_ERR_ALLOC_FAIL; 1397 if ((r = sshkey_putb(key, b)) != 0) 1398 goto out; 1399 if ((uu = sshbuf_dtob64_string(b, 0)) == NULL) { 1400 r = SSH_ERR_ALLOC_FAIL; 1401 goto out; 1402 } 1403 /* Success */ 1404 if (b64p != NULL) { 1405 *b64p = uu; 1406 uu = NULL; 1407 } 1408 r = 0; 1409 out: 1410 sshbuf_free(b); 1411 free(uu); 1412 return r; 1413 } 1414 1415 int 1416 sshkey_format_text(const struct sshkey *key, struct sshbuf *b) 1417 { 1418 int r = SSH_ERR_INTERNAL_ERROR; 1419 char *uu = NULL; 1420 1421 if ((r = sshkey_to_base64(key, &uu)) != 0) 1422 goto out; 1423 if ((r = sshbuf_putf(b, "%s %s", 1424 sshkey_ssh_name(key), uu)) != 0) 1425 goto out; 1426 r = 0; 1427 out: 1428 free(uu); 1429 return r; 1430 } 1431 1432 int 1433 sshkey_write(const struct sshkey *key, FILE *f) 1434 { 1435 struct sshbuf *b = NULL; 1436 int r = SSH_ERR_INTERNAL_ERROR; 1437 1438 if ((b = sshbuf_new()) == NULL) 1439 return SSH_ERR_ALLOC_FAIL; 1440 if ((r = sshkey_format_text(key, b)) != 0) 1441 goto out; 1442 if (fwrite(sshbuf_ptr(b), sshbuf_len(b), 1, f) != 1) { 1443 if (feof(f)) 1444 errno = EPIPE; 1445 r = SSH_ERR_SYSTEM_ERROR; 1446 goto out; 1447 } 1448 /* Success */ 1449 r = 0; 1450 out: 1451 sshbuf_free(b); 1452 return r; 1453 } 1454 1455 const char * 1456 sshkey_cert_type(const struct sshkey *k) 1457 { 1458 switch (k->cert->type) { 1459 case SSH2_CERT_TYPE_USER: 1460 return "user"; 1461 case SSH2_CERT_TYPE_HOST: 1462 return "host"; 1463 default: 1464 return "unknown"; 1465 } 1466 } 1467 1468 int 1469 sshkey_check_rsa_length(const struct sshkey *k, int min_size) 1470 { 1471 #ifdef WITH_OPENSSL 1472 int nbits; 1473 1474 if (k == NULL || k->pkey == NULL || 1475 (k->type != KEY_RSA && k->type != KEY_RSA_CERT)) 1476 return 0; 1477 nbits = EVP_PKEY_bits(k->pkey); 1478 if (nbits < SSH_RSA_MINIMUM_MODULUS_SIZE || 1479 (min_size > 0 && nbits < min_size)) 1480 return SSH_ERR_KEY_LENGTH; 1481 #endif /* WITH_OPENSSL */ 1482 return 0; 1483 } 1484 1485 #if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) 1486 int 1487 sshkey_ecdsa_key_to_nid(const EC_KEY *k) 1488 { 1489 const EC_GROUP *g; 1490 int nid; 1491 1492 if (k == NULL || (g = EC_KEY_get0_group(k)) == NULL) 1493 return -1; 1494 if ((nid = EC_GROUP_get_curve_name(g)) <= 0) 1495 return -1; 1496 return nid; 1497 } 1498 1499 int 1500 sshkey_ecdsa_pkey_to_nid(EVP_PKEY *pkey) 1501 { 1502 return sshkey_ecdsa_key_to_nid(EVP_PKEY_get0_EC_KEY(pkey)); 1503 } 1504 #endif /* defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) */ 1505 1506 int 1507 sshkey_generate(int type, u_int bits, struct sshkey **keyp) 1508 { 1509 struct sshkey *k; 1510 int ret = SSH_ERR_INTERNAL_ERROR; 1511 const struct sshkey_impl *impl; 1512 1513 if (keyp == NULL || sshkey_type_is_cert(type)) 1514 return SSH_ERR_INVALID_ARGUMENT; 1515 *keyp = NULL; 1516 if ((impl = sshkey_impl_from_type(type)) == NULL) 1517 return SSH_ERR_KEY_TYPE_UNKNOWN; 1518 if (impl->funcs->generate == NULL) 1519 return SSH_ERR_FEATURE_UNSUPPORTED; 1520 if ((k = sshkey_new(KEY_UNSPEC)) == NULL) 1521 return SSH_ERR_ALLOC_FAIL; 1522 k->type = type; 1523 if ((ret = impl->funcs->generate(k, bits)) != 0) { 1524 sshkey_free(k); 1525 return ret; 1526 } 1527 /* success */ 1528 *keyp = k; 1529 return 0; 1530 } 1531 1532 int 1533 sshkey_cert_copy(const struct sshkey *from_key, struct sshkey *to_key) 1534 { 1535 u_int i; 1536 const struct sshkey_cert *from; 1537 struct sshkey_cert *to; 1538 int r = SSH_ERR_INTERNAL_ERROR; 1539 1540 if (to_key == NULL || (from = from_key->cert) == NULL) 1541 return SSH_ERR_INVALID_ARGUMENT; 1542 1543 if ((to = cert_new()) == NULL) 1544 return SSH_ERR_ALLOC_FAIL; 1545 1546 if ((r = sshbuf_putb(to->certblob, from->certblob)) != 0 || 1547 (r = sshbuf_putb(to->critical, from->critical)) != 0 || 1548 (r = sshbuf_putb(to->extensions, from->extensions)) != 0) 1549 goto out; 1550 1551 to->serial = from->serial; 1552 to->type = from->type; 1553 if (from->key_id == NULL) 1554 to->key_id = NULL; 1555 else if ((to->key_id = strdup(from->key_id)) == NULL) { 1556 r = SSH_ERR_ALLOC_FAIL; 1557 goto out; 1558 } 1559 to->valid_after = from->valid_after; 1560 to->valid_before = from->valid_before; 1561 if (from->signature_key == NULL) 1562 to->signature_key = NULL; 1563 else if ((r = sshkey_from_private(from->signature_key, 1564 &to->signature_key)) != 0) 1565 goto out; 1566 if (from->signature_type != NULL && 1567 (to->signature_type = strdup(from->signature_type)) == NULL) { 1568 r = SSH_ERR_ALLOC_FAIL; 1569 goto out; 1570 } 1571 if (from->nprincipals > SSHKEY_CERT_MAX_PRINCIPALS) { 1572 r = SSH_ERR_INVALID_ARGUMENT; 1573 goto out; 1574 } 1575 if (from->nprincipals > 0) { 1576 if ((to->principals = calloc(from->nprincipals, 1577 sizeof(*to->principals))) == NULL) { 1578 r = SSH_ERR_ALLOC_FAIL; 1579 goto out; 1580 } 1581 for (i = 0; i < from->nprincipals; i++) { 1582 to->principals[i] = strdup(from->principals[i]); 1583 if (to->principals[i] == NULL) { 1584 to->nprincipals = i; 1585 r = SSH_ERR_ALLOC_FAIL; 1586 goto out; 1587 } 1588 } 1589 } 1590 to->nprincipals = from->nprincipals; 1591 1592 /* success */ 1593 cert_free(to_key->cert); 1594 to_key->cert = to; 1595 to = NULL; 1596 r = 0; 1597 out: 1598 cert_free(to); 1599 return r; 1600 } 1601 1602 int 1603 sshkey_copy_public_sk(const struct sshkey *from, struct sshkey *to) 1604 { 1605 /* Append security-key application string */ 1606 if ((to->sk_application = strdup(from->sk_application)) == NULL) 1607 return SSH_ERR_ALLOC_FAIL; 1608 return 0; 1609 } 1610 1611 int 1612 sshkey_from_private(const struct sshkey *k, struct sshkey **pkp) 1613 { 1614 struct sshkey *n = NULL; 1615 int r = SSH_ERR_INTERNAL_ERROR; 1616 const struct sshkey_impl *impl; 1617 1618 *pkp = NULL; 1619 if ((impl = sshkey_impl_from_key(k)) == NULL) 1620 return SSH_ERR_KEY_TYPE_UNKNOWN; 1621 if ((n = sshkey_new(k->type)) == NULL) { 1622 r = SSH_ERR_ALLOC_FAIL; 1623 goto out; 1624 } 1625 if ((r = impl->funcs->copy_public(k, n)) != 0) 1626 goto out; 1627 if (sshkey_is_cert(k) && (r = sshkey_cert_copy(k, n)) != 0) 1628 goto out; 1629 /* success */ 1630 *pkp = n; 1631 n = NULL; 1632 r = 0; 1633 out: 1634 sshkey_free(n); 1635 return r; 1636 } 1637 1638 int 1639 sshkey_is_shielded(struct sshkey *k) 1640 { 1641 return k != NULL && k->shielded_private != NULL; 1642 } 1643 1644 int 1645 sshkey_shield_private(struct sshkey *k) 1646 { 1647 struct sshbuf *prvbuf = NULL; 1648 u_char *prekey = NULL, *enc = NULL, keyiv[SSH_DIGEST_MAX_LENGTH]; 1649 struct sshcipher_ctx *cctx = NULL; 1650 const struct sshcipher *cipher; 1651 size_t i, enclen = 0; 1652 struct sshkey *kswap = NULL, tmp; 1653 int r = SSH_ERR_INTERNAL_ERROR; 1654 1655 #ifdef DEBUG_PK 1656 fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k)); 1657 #endif 1658 if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) { 1659 r = SSH_ERR_INVALID_ARGUMENT; 1660 goto out; 1661 } 1662 if (cipher_keylen(cipher) + cipher_ivlen(cipher) > 1663 ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) { 1664 r = SSH_ERR_INTERNAL_ERROR; 1665 goto out; 1666 } 1667 1668 /* Prepare a random pre-key, and from it an ephemeral key */ 1669 if ((r = sshkey_prekey_alloc(&prekey, SSHKEY_SHIELD_PREKEY_LEN)) != 0) 1670 goto out; 1671 arc4random_buf(prekey, SSHKEY_SHIELD_PREKEY_LEN); 1672 if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH, 1673 prekey, SSHKEY_SHIELD_PREKEY_LEN, 1674 keyiv, SSH_DIGEST_MAX_LENGTH)) != 0) 1675 goto out; 1676 #ifdef DEBUG_PK 1677 fprintf(stderr, "%s: key+iv\n", __func__); 1678 sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH), 1679 stderr); 1680 #endif 1681 if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher), 1682 keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 1)) != 0) 1683 goto out; 1684 1685 /* Serialise and encrypt the private key using the ephemeral key */ 1686 if ((prvbuf = sshbuf_new()) == NULL) { 1687 r = SSH_ERR_ALLOC_FAIL; 1688 goto out; 1689 } 1690 if (sshkey_is_shielded(k) && (r = sshkey_unshield_private(k)) != 0) 1691 goto out; 1692 if ((r = sshkey_private_serialize(k, prvbuf)) != 0) 1693 goto out; 1694 /* pad to cipher blocksize */ 1695 i = 0; 1696 while (sshbuf_len(prvbuf) % cipher_blocksize(cipher)) { 1697 if ((r = sshbuf_put_u8(prvbuf, ++i & 0xff)) != 0) 1698 goto out; 1699 } 1700 #ifdef DEBUG_PK 1701 fprintf(stderr, "%s: serialised\n", __func__); 1702 sshbuf_dump(prvbuf, stderr); 1703 #endif 1704 /* encrypt */ 1705 enclen = sshbuf_len(prvbuf); 1706 if ((enc = malloc(enclen)) == NULL) { 1707 r = SSH_ERR_ALLOC_FAIL; 1708 goto out; 1709 } 1710 if ((r = cipher_crypt(cctx, 0, enc, 1711 sshbuf_ptr(prvbuf), sshbuf_len(prvbuf), 0, 0)) != 0) 1712 goto out; 1713 #ifdef DEBUG_PK 1714 fprintf(stderr, "%s: encrypted\n", __func__); 1715 sshbuf_dump_data(enc, enclen, stderr); 1716 #endif 1717 1718 /* Make a scrubbed, public-only copy of our private key argument */ 1719 if ((r = sshkey_from_private(k, &kswap)) != 0) 1720 goto out; 1721 1722 /* Swap the private key out (it will be destroyed below) */ 1723 tmp = *kswap; 1724 *kswap = *k; 1725 *k = tmp; 1726 1727 /* Insert the shielded key into our argument */ 1728 k->shielded_private = enc; 1729 k->shielded_len = enclen; 1730 k->shield_prekey = prekey; 1731 k->shield_prekey_len = SSHKEY_SHIELD_PREKEY_LEN; 1732 enc = prekey = NULL; /* transferred */ 1733 enclen = 0; 1734 1735 /* preserve key fields that are required for correct operation */ 1736 k->sk_flags = kswap->sk_flags; 1737 1738 /* success */ 1739 r = 0; 1740 1741 out: 1742 /* XXX behaviour on error - invalidate original private key? */ 1743 cipher_free(cctx); 1744 explicit_bzero(keyiv, sizeof(keyiv)); 1745 explicit_bzero(&tmp, sizeof(tmp)); 1746 freezero(enc, enclen); 1747 sshkey_prekey_free(prekey, SSHKEY_SHIELD_PREKEY_LEN); 1748 sshkey_free(kswap); 1749 sshbuf_free(prvbuf); 1750 return r; 1751 } 1752 1753 /* Check deterministic padding after private key */ 1754 static int 1755 private2_check_padding(struct sshbuf *decrypted) 1756 { 1757 u_char pad; 1758 size_t i; 1759 int r; 1760 1761 i = 0; 1762 while (sshbuf_len(decrypted)) { 1763 if ((r = sshbuf_get_u8(decrypted, &pad)) != 0) 1764 goto out; 1765 if (pad != (++i & 0xff)) { 1766 r = SSH_ERR_INVALID_FORMAT; 1767 goto out; 1768 } 1769 } 1770 /* success */ 1771 r = 0; 1772 out: 1773 explicit_bzero(&pad, sizeof(pad)); 1774 explicit_bzero(&i, sizeof(i)); 1775 return r; 1776 } 1777 1778 int 1779 sshkey_unshield_private(struct sshkey *k) 1780 { 1781 struct sshbuf *prvbuf = NULL; 1782 u_char *cp, keyiv[SSH_DIGEST_MAX_LENGTH]; 1783 struct sshcipher_ctx *cctx = NULL; 1784 const struct sshcipher *cipher; 1785 struct sshkey *kswap = NULL, tmp; 1786 int r = SSH_ERR_INTERNAL_ERROR; 1787 1788 #ifdef DEBUG_PK 1789 fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k)); 1790 #endif 1791 if (!sshkey_is_shielded(k)) 1792 return 0; /* nothing to do */ 1793 1794 if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) { 1795 r = SSH_ERR_INVALID_ARGUMENT; 1796 goto out; 1797 } 1798 if (cipher_keylen(cipher) + cipher_ivlen(cipher) > 1799 ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) { 1800 r = SSH_ERR_INTERNAL_ERROR; 1801 goto out; 1802 } 1803 /* check size of shielded key blob */ 1804 if (k->shielded_len < cipher_blocksize(cipher) || 1805 (k->shielded_len % cipher_blocksize(cipher)) != 0) { 1806 r = SSH_ERR_INVALID_FORMAT; 1807 goto out; 1808 } 1809 1810 /* Calculate the ephemeral key from the prekey */ 1811 if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH, 1812 k->shield_prekey, k->shield_prekey_len, 1813 keyiv, SSH_DIGEST_MAX_LENGTH)) != 0) 1814 goto out; 1815 if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher), 1816 keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 0)) != 0) 1817 goto out; 1818 #ifdef DEBUG_PK 1819 fprintf(stderr, "%s: key+iv\n", __func__); 1820 sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH), 1821 stderr); 1822 #endif 1823 1824 /* Decrypt and parse the shielded private key using the ephemeral key */ 1825 if ((prvbuf = sshbuf_new()) == NULL) { 1826 r = SSH_ERR_ALLOC_FAIL; 1827 goto out; 1828 } 1829 if ((r = sshbuf_reserve(prvbuf, k->shielded_len, &cp)) != 0) 1830 goto out; 1831 /* decrypt */ 1832 #ifdef DEBUG_PK 1833 fprintf(stderr, "%s: encrypted\n", __func__); 1834 sshbuf_dump_data(k->shielded_private, k->shielded_len, stderr); 1835 #endif 1836 if ((r = cipher_crypt(cctx, 0, cp, 1837 k->shielded_private, k->shielded_len, 0, 0)) != 0) 1838 goto out; 1839 #ifdef DEBUG_PK 1840 fprintf(stderr, "%s: serialised\n", __func__); 1841 sshbuf_dump(prvbuf, stderr); 1842 #endif 1843 /* Parse private key */ 1844 if ((r = sshkey_private_deserialize(prvbuf, &kswap)) != 0) 1845 goto out; 1846 1847 if ((r = private2_check_padding(prvbuf)) != 0) 1848 goto out; 1849 1850 /* Swap the parsed key back into place */ 1851 tmp = *kswap; 1852 *kswap = *k; 1853 *k = tmp; 1854 1855 /* success */ 1856 r = 0; 1857 1858 out: 1859 cipher_free(cctx); 1860 explicit_bzero(keyiv, sizeof(keyiv)); 1861 explicit_bzero(&tmp, sizeof(tmp)); 1862 sshkey_free(kswap); 1863 sshbuf_free(prvbuf); 1864 return r; 1865 } 1866 1867 static int 1868 cert_parse(struct sshbuf *b, struct sshkey *key, struct sshbuf *certbuf) 1869 { 1870 struct sshbuf *principals = NULL, *crit = NULL; 1871 struct sshbuf *exts = NULL, *ca = NULL; 1872 u_char *sig = NULL; 1873 size_t signed_len = 0, slen = 0, kidlen = 0; 1874 int ret = SSH_ERR_INTERNAL_ERROR; 1875 1876 /* Copy the entire key blob for verification and later serialisation */ 1877 if ((ret = sshbuf_putb(key->cert->certblob, certbuf)) != 0) 1878 return ret; 1879 1880 /* Parse body of certificate up to signature */ 1881 if ((ret = sshbuf_get_u64(b, &key->cert->serial)) != 0 || 1882 (ret = sshbuf_get_u32(b, &key->cert->type)) != 0 || 1883 (ret = sshbuf_get_cstring(b, &key->cert->key_id, &kidlen)) != 0 || 1884 (ret = sshbuf_froms(b, &principals)) != 0 || 1885 (ret = sshbuf_get_u64(b, &key->cert->valid_after)) != 0 || 1886 (ret = sshbuf_get_u64(b, &key->cert->valid_before)) != 0 || 1887 (ret = sshbuf_froms(b, &crit)) != 0 || 1888 (ret = sshbuf_froms(b, &exts)) != 0 || 1889 (ret = sshbuf_get_string_direct(b, NULL, NULL)) != 0 || 1890 (ret = sshbuf_froms(b, &ca)) != 0) { 1891 /* XXX debug print error for ret */ 1892 ret = SSH_ERR_INVALID_FORMAT; 1893 goto out; 1894 } 1895 1896 /* Signature is left in the buffer so we can calculate this length */ 1897 signed_len = sshbuf_len(key->cert->certblob) - sshbuf_len(b); 1898 1899 if ((ret = sshbuf_get_string(b, &sig, &slen)) != 0) { 1900 ret = SSH_ERR_INVALID_FORMAT; 1901 goto out; 1902 } 1903 1904 if (key->cert->type != SSH2_CERT_TYPE_USER && 1905 key->cert->type != SSH2_CERT_TYPE_HOST) { 1906 ret = SSH_ERR_KEY_CERT_UNKNOWN_TYPE; 1907 goto out; 1908 } 1909 1910 /* Parse principals section */ 1911 while (sshbuf_len(principals) > 0) { 1912 char *principal = NULL; 1913 char **oprincipals = NULL; 1914 1915 if (key->cert->nprincipals >= SSHKEY_CERT_MAX_PRINCIPALS) { 1916 ret = SSH_ERR_INVALID_FORMAT; 1917 goto out; 1918 } 1919 if ((ret = sshbuf_get_cstring(principals, &principal, 1920 NULL)) != 0) { 1921 ret = SSH_ERR_INVALID_FORMAT; 1922 goto out; 1923 } 1924 oprincipals = key->cert->principals; 1925 key->cert->principals = recallocarray(key->cert->principals, 1926 key->cert->nprincipals, key->cert->nprincipals + 1, 1927 sizeof(*key->cert->principals)); 1928 if (key->cert->principals == NULL) { 1929 free(principal); 1930 key->cert->principals = oprincipals; 1931 ret = SSH_ERR_ALLOC_FAIL; 1932 goto out; 1933 } 1934 key->cert->principals[key->cert->nprincipals++] = principal; 1935 } 1936 1937 /* 1938 * Stash a copies of the critical options and extensions sections 1939 * for later use. 1940 */ 1941 if ((ret = sshbuf_putb(key->cert->critical, crit)) != 0 || 1942 (exts != NULL && 1943 (ret = sshbuf_putb(key->cert->extensions, exts)) != 0)) 1944 goto out; 1945 1946 /* 1947 * Validate critical options and extensions sections format. 1948 */ 1949 while (sshbuf_len(crit) != 0) { 1950 if ((ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0 || 1951 (ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0) { 1952 sshbuf_reset(key->cert->critical); 1953 ret = SSH_ERR_INVALID_FORMAT; 1954 goto out; 1955 } 1956 } 1957 while (exts != NULL && sshbuf_len(exts) != 0) { 1958 if ((ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0 || 1959 (ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0) { 1960 sshbuf_reset(key->cert->extensions); 1961 ret = SSH_ERR_INVALID_FORMAT; 1962 goto out; 1963 } 1964 } 1965 1966 /* Parse CA key and check signature */ 1967 if (sshkey_from_blob_internal(ca, &key->cert->signature_key, 0) != 0) { 1968 ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 1969 goto out; 1970 } 1971 if (!sshkey_type_is_valid_ca(key->cert->signature_key->type)) { 1972 ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 1973 goto out; 1974 } 1975 if ((ret = sshkey_verify(key->cert->signature_key, sig, slen, 1976 sshbuf_ptr(key->cert->certblob), signed_len, NULL, 0, NULL)) != 0) 1977 goto out; 1978 if ((ret = sshkey_get_sigtype(sig, slen, 1979 &key->cert->signature_type)) != 0) 1980 goto out; 1981 1982 /* Success */ 1983 ret = 0; 1984 out: 1985 sshbuf_free(ca); 1986 sshbuf_free(crit); 1987 sshbuf_free(exts); 1988 sshbuf_free(principals); 1989 free(sig); 1990 return ret; 1991 } 1992 1993 int 1994 sshkey_deserialize_sk(struct sshbuf *b, struct sshkey *key) 1995 { 1996 /* Parse additional security-key application string */ 1997 if (sshbuf_get_cstring(b, &key->sk_application, NULL) != 0) 1998 return SSH_ERR_INVALID_FORMAT; 1999 return 0; 2000 } 2001 2002 static int 2003 sshkey_from_blob_internal(struct sshbuf *b, struct sshkey **keyp, 2004 int allow_cert) 2005 { 2006 int type, ret = SSH_ERR_INTERNAL_ERROR; 2007 char *ktype = NULL; 2008 struct sshkey *key = NULL; 2009 struct sshbuf *copy; 2010 const struct sshkey_impl *impl; 2011 2012 #ifdef DEBUG_PK /* XXX */ 2013 sshbuf_dump(b, stderr); 2014 #endif 2015 if (keyp != NULL) 2016 *keyp = NULL; 2017 if ((copy = sshbuf_fromb(b)) == NULL) { 2018 ret = SSH_ERR_ALLOC_FAIL; 2019 goto out; 2020 } 2021 if (sshbuf_get_cstring(b, &ktype, NULL) != 0) { 2022 ret = SSH_ERR_INVALID_FORMAT; 2023 goto out; 2024 } 2025 2026 type = sshkey_type_from_name(ktype); 2027 if (!allow_cert && sshkey_type_is_cert(type)) { 2028 ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 2029 goto out; 2030 } 2031 if ((impl = sshkey_impl_from_type(type)) == NULL) { 2032 ret = SSH_ERR_KEY_TYPE_UNKNOWN; 2033 goto out; 2034 } 2035 if ((key = sshkey_new(type)) == NULL) { 2036 ret = SSH_ERR_ALLOC_FAIL; 2037 goto out; 2038 } 2039 if (sshkey_type_is_cert(type)) { 2040 /* Skip nonce that precedes all certificates */ 2041 if (sshbuf_get_string_direct(b, NULL, NULL) != 0) { 2042 ret = SSH_ERR_INVALID_FORMAT; 2043 goto out; 2044 } 2045 } 2046 if ((ret = impl->funcs->deserialize_public(ktype, b, key)) != 0) 2047 goto out; 2048 2049 /* Parse certificate potion */ 2050 if (sshkey_is_cert(key) && (ret = cert_parse(b, key, copy)) != 0) 2051 goto out; 2052 2053 if (key != NULL && sshbuf_len(b) != 0) { 2054 ret = SSH_ERR_INVALID_FORMAT; 2055 goto out; 2056 } 2057 ret = 0; 2058 if (keyp != NULL) { 2059 *keyp = key; 2060 key = NULL; 2061 } 2062 out: 2063 sshbuf_free(copy); 2064 sshkey_free(key); 2065 free(ktype); 2066 return ret; 2067 } 2068 2069 int 2070 sshkey_from_blob(const u_char *blob, size_t blen, struct sshkey **keyp) 2071 { 2072 struct sshbuf *b; 2073 int r; 2074 2075 if ((b = sshbuf_from(blob, blen)) == NULL) 2076 return SSH_ERR_ALLOC_FAIL; 2077 r = sshkey_from_blob_internal(b, keyp, 1); 2078 sshbuf_free(b); 2079 return r; 2080 } 2081 2082 int 2083 sshkey_fromb(struct sshbuf *b, struct sshkey **keyp) 2084 { 2085 return sshkey_from_blob_internal(b, keyp, 1); 2086 } 2087 2088 int 2089 sshkey_froms(struct sshbuf *buf, struct sshkey **keyp) 2090 { 2091 struct sshbuf *b; 2092 int r; 2093 2094 if ((r = sshbuf_froms(buf, &b)) != 0) 2095 return r; 2096 r = sshkey_from_blob_internal(b, keyp, 1); 2097 sshbuf_free(b); 2098 return r; 2099 } 2100 2101 int 2102 sshkey_get_sigtype(const u_char *sig, size_t siglen, char **sigtypep) 2103 { 2104 int r; 2105 struct sshbuf *b = NULL; 2106 char *sigtype = NULL; 2107 2108 if (sigtypep != NULL) 2109 *sigtypep = NULL; 2110 if ((b = sshbuf_from(sig, siglen)) == NULL) 2111 return SSH_ERR_ALLOC_FAIL; 2112 if ((r = sshbuf_get_cstring(b, &sigtype, NULL)) != 0) 2113 goto out; 2114 /* success */ 2115 if (sigtypep != NULL) { 2116 *sigtypep = sigtype; 2117 sigtype = NULL; 2118 } 2119 r = 0; 2120 out: 2121 free(sigtype); 2122 sshbuf_free(b); 2123 return r; 2124 } 2125 2126 /* 2127 * 2128 * Checks whether a certificate's signature type is allowed. 2129 * Returns 0 (success) if the certificate signature type appears in the 2130 * "allowed" pattern-list, or the key is not a certificate to begin with. 2131 * Otherwise returns a ssherr.h code. 2132 */ 2133 int 2134 sshkey_check_cert_sigtype(const struct sshkey *key, const char *allowed) 2135 { 2136 if (key == NULL || allowed == NULL) 2137 return SSH_ERR_INVALID_ARGUMENT; 2138 if (!sshkey_type_is_cert(key->type)) 2139 return 0; 2140 if (key->cert == NULL || key->cert->signature_type == NULL) 2141 return SSH_ERR_INVALID_ARGUMENT; 2142 if (match_pattern_list(key->cert->signature_type, allowed, 0) != 1) 2143 return SSH_ERR_SIGN_ALG_UNSUPPORTED; 2144 return 0; 2145 } 2146 2147 /* 2148 * Returns the expected signature algorithm for a given public key algorithm. 2149 */ 2150 const char * 2151 sshkey_sigalg_by_name(const char *name) 2152 { 2153 const struct sshkey_impl *impl; 2154 int i; 2155 2156 for (i = 0; keyimpls[i] != NULL; i++) { 2157 impl = keyimpls[i]; 2158 if (strcmp(impl->name, name) != 0) 2159 continue; 2160 if (impl->sigalg != NULL) 2161 return impl->sigalg; 2162 if (!impl->cert) 2163 return impl->name; 2164 return sshkey_ssh_name_from_type_nid( 2165 sshkey_type_plain(impl->type), impl->nid); 2166 } 2167 return NULL; 2168 } 2169 2170 /* 2171 * Verifies that the signature algorithm appearing inside the signature blob 2172 * matches that which was requested. 2173 */ 2174 int 2175 sshkey_check_sigtype(const u_char *sig, size_t siglen, 2176 const char *requested_alg) 2177 { 2178 const char *expected_alg; 2179 char *sigtype = NULL; 2180 int r; 2181 2182 if (requested_alg == NULL) 2183 return 0; 2184 if ((expected_alg = sshkey_sigalg_by_name(requested_alg)) == NULL) 2185 return SSH_ERR_INVALID_ARGUMENT; 2186 if ((r = sshkey_get_sigtype(sig, siglen, &sigtype)) != 0) 2187 return r; 2188 r = strcmp(expected_alg, sigtype) == 0; 2189 free(sigtype); 2190 return r ? 0 : SSH_ERR_SIGN_ALG_UNSUPPORTED; 2191 } 2192 2193 int 2194 sshkey_sign(struct sshkey *key, 2195 u_char **sigp, size_t *lenp, 2196 const u_char *data, size_t datalen, 2197 const char *alg, const char *sk_provider, const char *sk_pin, u_int compat) 2198 { 2199 int was_shielded = sshkey_is_shielded(key); 2200 int r2, r = SSH_ERR_INTERNAL_ERROR; 2201 const struct sshkey_impl *impl; 2202 2203 if (sigp != NULL) 2204 *sigp = NULL; 2205 if (lenp != NULL) 2206 *lenp = 0; 2207 if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE) 2208 return SSH_ERR_INVALID_ARGUMENT; 2209 if ((impl = sshkey_impl_from_key(key)) == NULL) 2210 return SSH_ERR_KEY_TYPE_UNKNOWN; 2211 if ((r = sshkey_unshield_private(key)) != 0) 2212 return r; 2213 if (sshkey_is_sk(key)) { 2214 r = sshsk_sign(sk_provider, key, sigp, lenp, data, 2215 datalen, compat, sk_pin); 2216 } else if ((key->flags & SSHKEY_FLAG_EXT) != 0) { 2217 r = pkcs11_sign(key, sigp, lenp, data, datalen, 2218 alg, sk_provider, sk_pin, compat); 2219 } else { 2220 if (impl->funcs->sign == NULL) 2221 r = SSH_ERR_SIGN_ALG_UNSUPPORTED; 2222 else { 2223 r = impl->funcs->sign(key, sigp, lenp, data, datalen, 2224 alg, sk_provider, sk_pin, compat); 2225 } 2226 } 2227 if (was_shielded && (r2 = sshkey_shield_private(key)) != 0) 2228 return r2; 2229 return r; 2230 } 2231 2232 /* 2233 * ssh_key_verify returns 0 for a correct signature and < 0 on error. 2234 * If "alg" specified, then the signature must use that algorithm. 2235 */ 2236 int 2237 sshkey_verify(const struct sshkey *key, 2238 const u_char *sig, size_t siglen, 2239 const u_char *data, size_t dlen, const char *alg, u_int compat, 2240 struct sshkey_sig_details **detailsp) 2241 { 2242 const struct sshkey_impl *impl; 2243 2244 if (detailsp != NULL) 2245 *detailsp = NULL; 2246 if (siglen == 0 || dlen > SSH_KEY_MAX_SIGN_DATA_SIZE) 2247 return SSH_ERR_INVALID_ARGUMENT; 2248 if ((impl = sshkey_impl_from_key(key)) == NULL) 2249 return SSH_ERR_KEY_TYPE_UNKNOWN; 2250 return impl->funcs->verify(key, sig, siglen, data, dlen, 2251 alg, compat, detailsp); 2252 } 2253 2254 /* Convert a plain key to their _CERT equivalent */ 2255 int 2256 sshkey_to_certified(struct sshkey *k) 2257 { 2258 int newtype; 2259 2260 if ((newtype = sshkey_type_certified(k->type)) == -1) 2261 return SSH_ERR_INVALID_ARGUMENT; 2262 if ((k->cert = cert_new()) == NULL) 2263 return SSH_ERR_ALLOC_FAIL; 2264 k->type = newtype; 2265 return 0; 2266 } 2267 2268 /* Convert a certificate to its raw key equivalent */ 2269 int 2270 sshkey_drop_cert(struct sshkey *k) 2271 { 2272 if (!sshkey_type_is_cert(k->type)) 2273 return SSH_ERR_KEY_TYPE_UNKNOWN; 2274 cert_free(k->cert); 2275 k->cert = NULL; 2276 k->type = sshkey_type_plain(k->type); 2277 return 0; 2278 } 2279 2280 /* Sign a certified key, (re-)generating the signed certblob. */ 2281 int 2282 sshkey_certify_custom(struct sshkey *k, struct sshkey *ca, const char *alg, 2283 const char *sk_provider, const char *sk_pin, 2284 sshkey_certify_signer *signer, void *signer_ctx) 2285 { 2286 const struct sshkey_impl *impl; 2287 struct sshbuf *principals = NULL; 2288 u_char *ca_blob = NULL, *sig_blob = NULL, nonce[32]; 2289 size_t i, ca_len, sig_len; 2290 int ret = SSH_ERR_INTERNAL_ERROR; 2291 struct sshbuf *cert = NULL; 2292 char *sigtype = NULL; 2293 2294 if (k == NULL || k->cert == NULL || 2295 k->cert->certblob == NULL || ca == NULL) 2296 return SSH_ERR_INVALID_ARGUMENT; 2297 if (!sshkey_is_cert(k)) 2298 return SSH_ERR_KEY_TYPE_UNKNOWN; 2299 if (!sshkey_type_is_valid_ca(ca->type)) 2300 return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 2301 if ((impl = sshkey_impl_from_key(k)) == NULL) 2302 return SSH_ERR_INTERNAL_ERROR; 2303 2304 /* 2305 * If no alg specified as argument but a signature_type was set, 2306 * then prefer that. If both were specified, then they must match. 2307 */ 2308 if (alg == NULL) 2309 alg = k->cert->signature_type; 2310 else if (k->cert->signature_type != NULL && 2311 strcmp(alg, k->cert->signature_type) != 0) 2312 return SSH_ERR_INVALID_ARGUMENT; 2313 2314 /* 2315 * If no signing algorithm or signature_type was specified and we're 2316 * using a RSA key, then default to a good signature algorithm. 2317 */ 2318 if (alg == NULL && ca->type == KEY_RSA) 2319 alg = "rsa-sha2-512"; 2320 2321 if ((ret = sshkey_to_blob(ca, &ca_blob, &ca_len)) != 0) 2322 return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 2323 2324 cert = k->cert->certblob; /* for readability */ 2325 sshbuf_reset(cert); 2326 if ((ret = sshbuf_put_cstring(cert, sshkey_ssh_name(k))) != 0) 2327 goto out; 2328 2329 /* -v01 certs put nonce first */ 2330 arc4random_buf(&nonce, sizeof(nonce)); 2331 if ((ret = sshbuf_put_string(cert, nonce, sizeof(nonce))) != 0) 2332 goto out; 2333 2334 /* Public key next */ 2335 if ((ret = impl->funcs->serialize_public(k, cert, 2336 SSHKEY_SERIALIZE_DEFAULT)) != 0) 2337 goto out; 2338 2339 /* Then remaining cert fields */ 2340 if ((ret = sshbuf_put_u64(cert, k->cert->serial)) != 0 || 2341 (ret = sshbuf_put_u32(cert, k->cert->type)) != 0 || 2342 (ret = sshbuf_put_cstring(cert, k->cert->key_id)) != 0) 2343 goto out; 2344 2345 if ((principals = sshbuf_new()) == NULL) { 2346 ret = SSH_ERR_ALLOC_FAIL; 2347 goto out; 2348 } 2349 for (i = 0; i < k->cert->nprincipals; i++) { 2350 if ((ret = sshbuf_put_cstring(principals, 2351 k->cert->principals[i])) != 0) 2352 goto out; 2353 } 2354 if ((ret = sshbuf_put_stringb(cert, principals)) != 0 || 2355 (ret = sshbuf_put_u64(cert, k->cert->valid_after)) != 0 || 2356 (ret = sshbuf_put_u64(cert, k->cert->valid_before)) != 0 || 2357 (ret = sshbuf_put_stringb(cert, k->cert->critical)) != 0 || 2358 (ret = sshbuf_put_stringb(cert, k->cert->extensions)) != 0 || 2359 (ret = sshbuf_put_string(cert, NULL, 0)) != 0 || /* Reserved */ 2360 (ret = sshbuf_put_string(cert, ca_blob, ca_len)) != 0) 2361 goto out; 2362 2363 /* Sign the whole mess */ 2364 if ((ret = signer(ca, &sig_blob, &sig_len, sshbuf_ptr(cert), 2365 sshbuf_len(cert), alg, sk_provider, sk_pin, 0, signer_ctx)) != 0) 2366 goto out; 2367 /* Check and update signature_type against what was actually used */ 2368 if ((ret = sshkey_get_sigtype(sig_blob, sig_len, &sigtype)) != 0) 2369 goto out; 2370 if (alg != NULL && strcmp(alg, sigtype) != 0) { 2371 ret = SSH_ERR_SIGN_ALG_UNSUPPORTED; 2372 goto out; 2373 } 2374 if (k->cert->signature_type == NULL) { 2375 k->cert->signature_type = sigtype; 2376 sigtype = NULL; 2377 } 2378 /* Append signature and we are done */ 2379 if ((ret = sshbuf_put_string(cert, sig_blob, sig_len)) != 0) 2380 goto out; 2381 ret = 0; 2382 out: 2383 if (ret != 0) 2384 sshbuf_reset(cert); 2385 free(sig_blob); 2386 free(ca_blob); 2387 free(sigtype); 2388 sshbuf_free(principals); 2389 return ret; 2390 } 2391 2392 static int 2393 default_key_sign(struct sshkey *key, u_char **sigp, size_t *lenp, 2394 const u_char *data, size_t datalen, 2395 const char *alg, const char *sk_provider, const char *sk_pin, 2396 u_int compat, void *ctx) 2397 { 2398 if (ctx != NULL) 2399 return SSH_ERR_INVALID_ARGUMENT; 2400 return sshkey_sign(key, sigp, lenp, data, datalen, alg, 2401 sk_provider, sk_pin, compat); 2402 } 2403 2404 int 2405 sshkey_certify(struct sshkey *k, struct sshkey *ca, const char *alg, 2406 const char *sk_provider, const char *sk_pin) 2407 { 2408 return sshkey_certify_custom(k, ca, alg, sk_provider, sk_pin, 2409 default_key_sign, NULL); 2410 } 2411 2412 int 2413 sshkey_cert_check_authority(const struct sshkey *k, 2414 int want_host, int wildcard_pattern, uint64_t verify_time, 2415 const char *name, const char **reason) 2416 { 2417 u_int i, principal_matches; 2418 2419 if (reason == NULL) 2420 return SSH_ERR_INVALID_ARGUMENT; 2421 if (!sshkey_is_cert(k)) { 2422 *reason = "Key is not a certificate"; 2423 return SSH_ERR_KEY_CERT_INVALID; 2424 } 2425 if (want_host) { 2426 if (k->cert->type != SSH2_CERT_TYPE_HOST) { 2427 *reason = "Certificate invalid: not a host certificate"; 2428 return SSH_ERR_KEY_CERT_INVALID; 2429 } 2430 } else { 2431 if (k->cert->type != SSH2_CERT_TYPE_USER) { 2432 *reason = "Certificate invalid: not a user certificate"; 2433 return SSH_ERR_KEY_CERT_INVALID; 2434 } 2435 } 2436 if (verify_time < k->cert->valid_after) { 2437 *reason = "Certificate invalid: not yet valid"; 2438 return SSH_ERR_KEY_CERT_INVALID; 2439 } 2440 if (verify_time >= k->cert->valid_before) { 2441 *reason = "Certificate invalid: expired"; 2442 return SSH_ERR_KEY_CERT_INVALID; 2443 } 2444 if (k->cert->nprincipals == 0) { 2445 *reason = "Certificate lacks principal list"; 2446 return SSH_ERR_KEY_CERT_INVALID; 2447 } 2448 if (name == NULL) 2449 return 0; /* principal matching not requested */ 2450 2451 principal_matches = 0; 2452 for (i = 0; i < k->cert->nprincipals; i++) { 2453 if (wildcard_pattern) { 2454 if (match_pattern(name, k->cert->principals[i])) { 2455 principal_matches = 1; 2456 break; 2457 } 2458 } else if (strcmp(name, k->cert->principals[i]) == 0) { 2459 principal_matches = 1; 2460 break; 2461 } 2462 } 2463 if (!principal_matches) { 2464 *reason = "Certificate invalid: name is not a listed " 2465 "principal"; 2466 return SSH_ERR_KEY_CERT_INVALID; 2467 } 2468 return 0; 2469 } 2470 2471 int 2472 sshkey_cert_check_authority_now(const struct sshkey *k, 2473 int want_host, int wildcard_pattern, const char *name, 2474 const char **reason) 2475 { 2476 time_t now; 2477 2478 if ((now = time(NULL)) < 0) { 2479 /* yikes - system clock before epoch! */ 2480 *reason = "Certificate invalid: not yet valid"; 2481 return SSH_ERR_KEY_CERT_INVALID; 2482 } 2483 return sshkey_cert_check_authority(k, want_host, wildcard_pattern, 2484 (uint64_t)now, name, reason); 2485 } 2486 2487 int 2488 sshkey_cert_check_host(const struct sshkey *key, const char *host, 2489 const char *ca_sign_algorithms, const char **reason) 2490 { 2491 int r; 2492 2493 if ((r = sshkey_cert_check_authority_now(key, 1, 1, host, reason)) != 0) 2494 return r; 2495 if (sshbuf_len(key->cert->critical) != 0) { 2496 *reason = "Certificate contains unsupported critical options"; 2497 return SSH_ERR_KEY_CERT_INVALID; 2498 } 2499 if (ca_sign_algorithms != NULL && 2500 (r = sshkey_check_cert_sigtype(key, ca_sign_algorithms)) != 0) { 2501 *reason = "Certificate signed with disallowed algorithm"; 2502 return SSH_ERR_KEY_CERT_INVALID; 2503 } 2504 return 0; 2505 } 2506 2507 size_t 2508 sshkey_format_cert_validity(const struct sshkey_cert *cert, char *s, size_t l) 2509 { 2510 char from[32], to[32], ret[128]; 2511 2512 *from = *to = '\0'; 2513 if (cert->valid_after == 0 && 2514 cert->valid_before == 0xffffffffffffffffULL) 2515 return strlcpy(s, "forever", l); 2516 2517 if (cert->valid_after != 0) 2518 format_absolute_time(cert->valid_after, from, sizeof(from)); 2519 if (cert->valid_before != 0xffffffffffffffffULL) 2520 format_absolute_time(cert->valid_before, to, sizeof(to)); 2521 2522 if (cert->valid_after == 0) 2523 snprintf(ret, sizeof(ret), "before %s", to); 2524 else if (cert->valid_before == 0xffffffffffffffffULL) 2525 snprintf(ret, sizeof(ret), "after %s", from); 2526 else 2527 snprintf(ret, sizeof(ret), "from %s to %s", from, to); 2528 2529 return strlcpy(s, ret, l); 2530 } 2531 2532 /* Common serialization for FIDO private keys */ 2533 int 2534 sshkey_serialize_private_sk(const struct sshkey *key, struct sshbuf *b) 2535 { 2536 int r; 2537 2538 if ((r = sshbuf_put_cstring(b, key->sk_application)) != 0 || 2539 (r = sshbuf_put_u8(b, key->sk_flags)) != 0 || 2540 (r = sshbuf_put_stringb(b, key->sk_key_handle)) != 0 || 2541 (r = sshbuf_put_stringb(b, key->sk_reserved)) != 0) 2542 return r; 2543 2544 return 0; 2545 } 2546 2547 static int 2548 sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf, 2549 enum sshkey_serialize_rep opts) 2550 { 2551 int r = SSH_ERR_INTERNAL_ERROR; 2552 int was_shielded = sshkey_is_shielded(key); 2553 struct sshbuf *b = NULL; 2554 const struct sshkey_impl *impl; 2555 2556 if ((impl = sshkey_impl_from_key(key)) == NULL) 2557 return SSH_ERR_INTERNAL_ERROR; 2558 if ((r = sshkey_unshield_private(key)) != 0) 2559 return r; 2560 if ((b = sshbuf_new()) == NULL) 2561 return SSH_ERR_ALLOC_FAIL; 2562 if ((r = sshbuf_put_cstring(b, sshkey_ssh_name(key))) != 0) 2563 goto out; 2564 if (sshkey_is_cert(key)) { 2565 if (key->cert == NULL || 2566 sshbuf_len(key->cert->certblob) == 0) { 2567 r = SSH_ERR_INVALID_ARGUMENT; 2568 goto out; 2569 } 2570 if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0) 2571 goto out; 2572 } 2573 if ((r = impl->funcs->serialize_private(key, b, opts)) != 0) 2574 goto out; 2575 2576 /* 2577 * success (but we still need to append the output to buf after 2578 * possibly re-shielding the private key) 2579 */ 2580 r = 0; 2581 out: 2582 if (was_shielded) 2583 r = sshkey_shield_private(key); 2584 if (r == 0) 2585 r = sshbuf_putb(buf, b); 2586 sshbuf_free(b); 2587 2588 return r; 2589 } 2590 2591 int 2592 sshkey_private_serialize(struct sshkey *key, struct sshbuf *b) 2593 { 2594 return sshkey_private_serialize_opt(key, b, 2595 SSHKEY_SERIALIZE_DEFAULT); 2596 } 2597 2598 2599 /* Shared deserialization of FIDO private key components */ 2600 int 2601 sshkey_private_deserialize_sk(struct sshbuf *buf, struct sshkey *k) 2602 { 2603 int r; 2604 2605 if ((k->sk_key_handle = sshbuf_new()) == NULL || 2606 (k->sk_reserved = sshbuf_new()) == NULL) 2607 return SSH_ERR_ALLOC_FAIL; 2608 if ((r = sshbuf_get_cstring(buf, &k->sk_application, NULL)) != 0 || 2609 (r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 || 2610 (r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 || 2611 (r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0) 2612 return r; 2613 2614 return 0; 2615 } 2616 2617 int 2618 sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp) 2619 { 2620 const struct sshkey_impl *impl; 2621 char *tname = NULL; 2622 char *expect_sk_application = NULL; 2623 u_char *expect_ed25519_pk = NULL; 2624 struct sshkey *k = NULL; 2625 int type, r = SSH_ERR_INTERNAL_ERROR; 2626 2627 if (kp != NULL) 2628 *kp = NULL; 2629 if ((r = sshbuf_get_cstring(buf, &tname, NULL)) != 0) 2630 goto out; 2631 type = sshkey_type_from_name(tname); 2632 if (sshkey_type_is_cert(type)) { 2633 /* 2634 * Certificate key private keys begin with the certificate 2635 * itself. Make sure this matches the type of the enclosing 2636 * private key. 2637 */ 2638 if ((r = sshkey_froms(buf, &k)) != 0) 2639 goto out; 2640 if (k->type != type) { 2641 r = SSH_ERR_KEY_CERT_MISMATCH; 2642 goto out; 2643 } 2644 /* For ECDSA keys, the group must match too */ 2645 if (k->type == KEY_ECDSA && 2646 k->ecdsa_nid != sshkey_ecdsa_nid_from_name(tname)) { 2647 r = SSH_ERR_KEY_CERT_MISMATCH; 2648 goto out; 2649 } 2650 /* 2651 * Several fields are redundant between certificate and 2652 * private key body, we require these to match. 2653 */ 2654 expect_sk_application = k->sk_application; 2655 expect_ed25519_pk = k->ed25519_pk; 2656 k->sk_application = NULL; 2657 k->ed25519_pk = NULL; 2658 } else { 2659 if ((k = sshkey_new(type)) == NULL) { 2660 r = SSH_ERR_ALLOC_FAIL; 2661 goto out; 2662 } 2663 } 2664 if ((impl = sshkey_impl_from_type(type)) == NULL) { 2665 r = SSH_ERR_INTERNAL_ERROR; 2666 goto out; 2667 } 2668 if ((r = impl->funcs->deserialize_private(tname, buf, k)) != 0) 2669 goto out; 2670 2671 if ((expect_sk_application != NULL && (k->sk_application == NULL || 2672 strcmp(expect_sk_application, k->sk_application) != 0)) || 2673 (expect_ed25519_pk != NULL && (k->ed25519_pk == NULL || 2674 memcmp(expect_ed25519_pk, k->ed25519_pk, ED25519_PK_SZ) != 0))) { 2675 r = SSH_ERR_KEY_CERT_MISMATCH; 2676 goto out; 2677 } 2678 /* success */ 2679 r = 0; 2680 if (kp != NULL) { 2681 *kp = k; 2682 k = NULL; 2683 } 2684 out: 2685 free(tname); 2686 sshkey_free(k); 2687 free(expect_sk_application); 2688 free(expect_ed25519_pk); 2689 return r; 2690 } 2691 2692 #if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) 2693 int 2694 sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public) 2695 { 2696 EC_POINT *nq = NULL; 2697 BIGNUM *order = NULL, *cofactor = NULL; 2698 int ret = SSH_ERR_KEY_INVALID_EC_VALUE; 2699 2700 /* 2701 * NB. This assumes OpenSSL has already verified that the public 2702 * point lies on the curve and that its coordinates are in [0, p). 2703 * This is done by EC_POINT_oct2point() on at least OpenSSL >= 1.1, 2704 * LibreSSL and BoringSSL. 2705 */ 2706 2707 /* Q != infinity */ 2708 if (EC_POINT_is_at_infinity(group, public)) 2709 goto out; 2710 2711 if ((cofactor = BN_new()) == NULL) { 2712 ret = SSH_ERR_ALLOC_FAIL; 2713 goto out; 2714 } 2715 if (EC_GROUP_get_cofactor(group, cofactor, NULL) != 1) 2716 goto out; 2717 2718 /* 2719 * Verify nQ == infinity (n == order of subgroup) 2720 * This check may be skipped for curves with cofactor 1, as per 2721 * NIST SP 800-56A, 5.6.2.3. 2722 */ 2723 if (!BN_is_one(cofactor)) { 2724 if ((order = BN_new()) == NULL) { 2725 ret = SSH_ERR_ALLOC_FAIL; 2726 goto out; 2727 } 2728 if (EC_GROUP_get_order(group, order, NULL) != 1) { 2729 ret = SSH_ERR_LIBCRYPTO_ERROR; 2730 goto out; 2731 } 2732 if ((nq = EC_POINT_new(group)) == NULL) { 2733 ret = SSH_ERR_ALLOC_FAIL; 2734 goto out; 2735 } 2736 if (EC_POINT_mul(group, nq, NULL, public, order, NULL) != 1) { 2737 ret = SSH_ERR_LIBCRYPTO_ERROR; 2738 goto out; 2739 } 2740 if (EC_POINT_is_at_infinity(group, nq) != 1) 2741 goto out; 2742 } 2743 2744 /* success */ 2745 ret = 0; 2746 out: 2747 BN_clear_free(cofactor); 2748 BN_clear_free(order); 2749 EC_POINT_free(nq); 2750 return ret; 2751 } 2752 2753 int 2754 sshkey_ec_validate_private(const EC_KEY *key) 2755 { 2756 BIGNUM *order = NULL, *tmp = NULL; 2757 int ret = SSH_ERR_KEY_INVALID_EC_VALUE; 2758 2759 if ((order = BN_new()) == NULL || (tmp = BN_new()) == NULL) { 2760 ret = SSH_ERR_ALLOC_FAIL; 2761 goto out; 2762 } 2763 2764 /* log2(private) > log2(order)/2 */ 2765 if (EC_GROUP_get_order(EC_KEY_get0_group(key), order, NULL) != 1) { 2766 ret = SSH_ERR_LIBCRYPTO_ERROR; 2767 goto out; 2768 } 2769 if (BN_num_bits(EC_KEY_get0_private_key(key)) <= 2770 BN_num_bits(order) / 2) 2771 goto out; 2772 2773 /* private < order - 1 */ 2774 if (!BN_sub(tmp, order, BN_value_one())) { 2775 ret = SSH_ERR_LIBCRYPTO_ERROR; 2776 goto out; 2777 } 2778 if (BN_cmp(EC_KEY_get0_private_key(key), tmp) >= 0) 2779 goto out; 2780 ret = 0; 2781 out: 2782 BN_clear_free(order); 2783 BN_clear_free(tmp); 2784 return ret; 2785 } 2786 2787 void 2788 sshkey_dump_ec_point(const EC_GROUP *group, const EC_POINT *point) 2789 { 2790 BIGNUM *x = NULL, *y = NULL; 2791 2792 if (point == NULL) { 2793 fputs("point=(NULL)\n", stderr); 2794 return; 2795 } 2796 if ((x = BN_new()) == NULL || (y = BN_new()) == NULL) { 2797 fprintf(stderr, "%s: BN_new failed\n", __func__); 2798 goto out; 2799 } 2800 if (EC_POINT_get_affine_coordinates(group, point, x, y, NULL) != 1) { 2801 fprintf(stderr, "%s: EC_POINT_get_affine_coordinates\n", 2802 __func__); 2803 goto out; 2804 } 2805 fputs("x=", stderr); 2806 BN_print_fp(stderr, x); 2807 fputs("\ny=", stderr); 2808 BN_print_fp(stderr, y); 2809 fputs("\n", stderr); 2810 out: 2811 BN_clear_free(x); 2812 BN_clear_free(y); 2813 } 2814 2815 void 2816 sshkey_dump_ec_key(const EC_KEY *key) 2817 { 2818 const BIGNUM *exponent; 2819 2820 sshkey_dump_ec_point(EC_KEY_get0_group(key), 2821 EC_KEY_get0_public_key(key)); 2822 fputs("exponent=", stderr); 2823 if ((exponent = EC_KEY_get0_private_key(key)) == NULL) 2824 fputs("(NULL)", stderr); 2825 else 2826 BN_print_fp(stderr, EC_KEY_get0_private_key(key)); 2827 fputs("\n", stderr); 2828 } 2829 #endif /* WITH_OPENSSL && OPENSSL_HAS_ECC */ 2830 2831 static int 2832 sshkey_private_to_blob2(struct sshkey *prv, struct sshbuf *blob, 2833 const char *passphrase, const char *comment, const char *ciphername, 2834 int rounds) 2835 { 2836 u_char *cp, *key = NULL, *pubkeyblob = NULL; 2837 u_char salt[SALT_LEN]; 2838 size_t i, pubkeylen, keylen, ivlen, blocksize, authlen; 2839 u_int check; 2840 int r = SSH_ERR_INTERNAL_ERROR; 2841 struct sshcipher_ctx *ciphercontext = NULL; 2842 const struct sshcipher *cipher; 2843 const char *kdfname = KDFNAME; 2844 struct sshbuf *encoded = NULL, *encrypted = NULL, *kdf = NULL; 2845 2846 if (rounds <= 0) 2847 rounds = DEFAULT_ROUNDS; 2848 if (passphrase == NULL || !strlen(passphrase)) { 2849 ciphername = "none"; 2850 kdfname = "none"; 2851 } else if (ciphername == NULL) 2852 ciphername = DEFAULT_CIPHERNAME; 2853 if ((cipher = cipher_by_name(ciphername)) == NULL) { 2854 r = SSH_ERR_INVALID_ARGUMENT; 2855 goto out; 2856 } 2857 2858 if ((kdf = sshbuf_new()) == NULL || 2859 (encoded = sshbuf_new()) == NULL || 2860 (encrypted = sshbuf_new()) == NULL) { 2861 r = SSH_ERR_ALLOC_FAIL; 2862 goto out; 2863 } 2864 blocksize = cipher_blocksize(cipher); 2865 keylen = cipher_keylen(cipher); 2866 ivlen = cipher_ivlen(cipher); 2867 authlen = cipher_authlen(cipher); 2868 if ((key = calloc(1, keylen + ivlen)) == NULL) { 2869 r = SSH_ERR_ALLOC_FAIL; 2870 goto out; 2871 } 2872 if (strcmp(kdfname, "bcrypt") == 0) { 2873 arc4random_buf(salt, SALT_LEN); 2874 if (bcrypt_pbkdf(passphrase, strlen(passphrase), 2875 salt, SALT_LEN, key, keylen + ivlen, rounds) < 0) { 2876 r = SSH_ERR_INVALID_ARGUMENT; 2877 goto out; 2878 } 2879 if ((r = sshbuf_put_string(kdf, salt, SALT_LEN)) != 0 || 2880 (r = sshbuf_put_u32(kdf, rounds)) != 0) 2881 goto out; 2882 } else if (strcmp(kdfname, "none") != 0) { 2883 /* Unsupported KDF type */ 2884 r = SSH_ERR_KEY_UNKNOWN_CIPHER; 2885 goto out; 2886 } 2887 if ((r = cipher_init(&ciphercontext, cipher, key, keylen, 2888 key + keylen, ivlen, 1)) != 0) 2889 goto out; 2890 2891 if ((r = sshbuf_put(encoded, AUTH_MAGIC, sizeof(AUTH_MAGIC))) != 0 || 2892 (r = sshbuf_put_cstring(encoded, ciphername)) != 0 || 2893 (r = sshbuf_put_cstring(encoded, kdfname)) != 0 || 2894 (r = sshbuf_put_stringb(encoded, kdf)) != 0 || 2895 (r = sshbuf_put_u32(encoded, 1)) != 0 || /* number of keys */ 2896 (r = sshkey_to_blob(prv, &pubkeyblob, &pubkeylen)) != 0 || 2897 (r = sshbuf_put_string(encoded, pubkeyblob, pubkeylen)) != 0) 2898 goto out; 2899 2900 /* set up the buffer that will be encrypted */ 2901 2902 /* Random check bytes */ 2903 check = arc4random(); 2904 if ((r = sshbuf_put_u32(encrypted, check)) != 0 || 2905 (r = sshbuf_put_u32(encrypted, check)) != 0) 2906 goto out; 2907 2908 /* append private key and comment*/ 2909 if ((r = sshkey_private_serialize(prv, encrypted)) != 0 || 2910 (r = sshbuf_put_cstring(encrypted, comment)) != 0) 2911 goto out; 2912 2913 /* padding */ 2914 i = 0; 2915 while (sshbuf_len(encrypted) % blocksize) { 2916 if ((r = sshbuf_put_u8(encrypted, ++i & 0xff)) != 0) 2917 goto out; 2918 } 2919 2920 /* length in destination buffer */ 2921 if ((r = sshbuf_put_u32(encoded, sshbuf_len(encrypted))) != 0) 2922 goto out; 2923 2924 /* encrypt */ 2925 if ((r = sshbuf_reserve(encoded, 2926 sshbuf_len(encrypted) + authlen, &cp)) != 0) 2927 goto out; 2928 if ((r = cipher_crypt(ciphercontext, 0, cp, 2929 sshbuf_ptr(encrypted), sshbuf_len(encrypted), 0, authlen)) != 0) 2930 goto out; 2931 2932 sshbuf_reset(blob); 2933 2934 /* assemble uuencoded key */ 2935 if ((r = sshbuf_put(blob, MARK_BEGIN, MARK_BEGIN_LEN)) != 0 || 2936 (r = sshbuf_dtob64(encoded, blob, 1)) != 0 || 2937 (r = sshbuf_put(blob, MARK_END, MARK_END_LEN)) != 0) 2938 goto out; 2939 2940 /* success */ 2941 r = 0; 2942 2943 out: 2944 sshbuf_free(kdf); 2945 sshbuf_free(encoded); 2946 sshbuf_free(encrypted); 2947 cipher_free(ciphercontext); 2948 explicit_bzero(salt, sizeof(salt)); 2949 if (key != NULL) 2950 freezero(key, keylen + ivlen); 2951 if (pubkeyblob != NULL) 2952 freezero(pubkeyblob, pubkeylen); 2953 return r; 2954 } 2955 2956 static int 2957 private2_uudecode(struct sshbuf *blob, struct sshbuf **decodedp) 2958 { 2959 const u_char *cp; 2960 size_t encoded_len; 2961 int r; 2962 u_char last; 2963 struct sshbuf *encoded = NULL, *decoded = NULL; 2964 2965 if (blob == NULL || decodedp == NULL) 2966 return SSH_ERR_INVALID_ARGUMENT; 2967 2968 *decodedp = NULL; 2969 2970 if ((encoded = sshbuf_new()) == NULL || 2971 (decoded = sshbuf_new()) == NULL) { 2972 r = SSH_ERR_ALLOC_FAIL; 2973 goto out; 2974 } 2975 2976 /* check preamble */ 2977 cp = sshbuf_ptr(blob); 2978 encoded_len = sshbuf_len(blob); 2979 if (encoded_len < (MARK_BEGIN_LEN + MARK_END_LEN) || 2980 memcmp(cp, MARK_BEGIN, MARK_BEGIN_LEN) != 0) { 2981 r = SSH_ERR_INVALID_FORMAT; 2982 goto out; 2983 } 2984 cp += MARK_BEGIN_LEN; 2985 encoded_len -= MARK_BEGIN_LEN; 2986 2987 /* Look for end marker, removing whitespace as we go */ 2988 while (encoded_len > 0) { 2989 if (*cp != '\n' && *cp != '\r') { 2990 if ((r = sshbuf_put_u8(encoded, *cp)) != 0) 2991 goto out; 2992 } 2993 last = *cp; 2994 encoded_len--; 2995 cp++; 2996 if (last == '\n') { 2997 if (encoded_len >= MARK_END_LEN && 2998 memcmp(cp, MARK_END, MARK_END_LEN) == 0) { 2999 /* \0 terminate */ 3000 if ((r = sshbuf_put_u8(encoded, 0)) != 0) 3001 goto out; 3002 break; 3003 } 3004 } 3005 } 3006 if (encoded_len == 0) { 3007 r = SSH_ERR_INVALID_FORMAT; 3008 goto out; 3009 } 3010 3011 /* decode base64 */ 3012 if ((r = sshbuf_b64tod(decoded, (char *)sshbuf_ptr(encoded))) != 0) 3013 goto out; 3014 3015 /* check magic */ 3016 if (sshbuf_len(decoded) < sizeof(AUTH_MAGIC) || 3017 memcmp(sshbuf_ptr(decoded), AUTH_MAGIC, sizeof(AUTH_MAGIC))) { 3018 r = SSH_ERR_INVALID_FORMAT; 3019 goto out; 3020 } 3021 /* success */ 3022 *decodedp = decoded; 3023 decoded = NULL; 3024 r = 0; 3025 out: 3026 sshbuf_free(encoded); 3027 sshbuf_free(decoded); 3028 return r; 3029 } 3030 3031 static int 3032 private2_decrypt(struct sshbuf *decoded, const char *passphrase, 3033 struct sshbuf **decryptedp, struct sshkey **pubkeyp) 3034 { 3035 char *ciphername = NULL, *kdfname = NULL; 3036 const struct sshcipher *cipher = NULL; 3037 int r = SSH_ERR_INTERNAL_ERROR; 3038 size_t keylen = 0, ivlen = 0, authlen = 0, slen = 0; 3039 struct sshbuf *kdf = NULL, *decrypted = NULL; 3040 struct sshcipher_ctx *ciphercontext = NULL; 3041 struct sshkey *pubkey = NULL; 3042 u_char *key = NULL, *salt = NULL, *dp; 3043 u_int blocksize, rounds, nkeys, encrypted_len, check1, check2; 3044 3045 if (decoded == NULL || decryptedp == NULL || pubkeyp == NULL) 3046 return SSH_ERR_INVALID_ARGUMENT; 3047 3048 *decryptedp = NULL; 3049 *pubkeyp = NULL; 3050 3051 if ((decrypted = sshbuf_new()) == NULL) { 3052 r = SSH_ERR_ALLOC_FAIL; 3053 goto out; 3054 } 3055 3056 /* parse public portion of key */ 3057 if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 || 3058 (r = sshbuf_get_cstring(decoded, &ciphername, NULL)) != 0 || 3059 (r = sshbuf_get_cstring(decoded, &kdfname, NULL)) != 0 || 3060 (r = sshbuf_froms(decoded, &kdf)) != 0 || 3061 (r = sshbuf_get_u32(decoded, &nkeys)) != 0) 3062 goto out; 3063 3064 if (nkeys != 1) { 3065 /* XXX only one key supported at present */ 3066 r = SSH_ERR_INVALID_FORMAT; 3067 goto out; 3068 } 3069 3070 if ((r = sshkey_froms(decoded, &pubkey)) != 0 || 3071 (r = sshbuf_get_u32(decoded, &encrypted_len)) != 0) 3072 goto out; 3073 3074 if ((cipher = cipher_by_name(ciphername)) == NULL) { 3075 r = SSH_ERR_KEY_UNKNOWN_CIPHER; 3076 goto out; 3077 } 3078 if (strcmp(kdfname, "none") != 0 && strcmp(kdfname, "bcrypt") != 0) { 3079 r = SSH_ERR_KEY_UNKNOWN_CIPHER; 3080 goto out; 3081 } 3082 if (strcmp(kdfname, "none") == 0 && strcmp(ciphername, "none") != 0) { 3083 r = SSH_ERR_INVALID_FORMAT; 3084 goto out; 3085 } 3086 if ((passphrase == NULL || strlen(passphrase) == 0) && 3087 strcmp(kdfname, "none") != 0) { 3088 /* passphrase required */ 3089 r = SSH_ERR_KEY_WRONG_PASSPHRASE; 3090 goto out; 3091 } 3092 3093 /* check size of encrypted key blob */ 3094 blocksize = cipher_blocksize(cipher); 3095 if (encrypted_len < blocksize || (encrypted_len % blocksize) != 0) { 3096 r = SSH_ERR_INVALID_FORMAT; 3097 goto out; 3098 } 3099 3100 /* setup key */ 3101 keylen = cipher_keylen(cipher); 3102 ivlen = cipher_ivlen(cipher); 3103 authlen = cipher_authlen(cipher); 3104 if ((key = calloc(1, keylen + ivlen)) == NULL) { 3105 r = SSH_ERR_ALLOC_FAIL; 3106 goto out; 3107 } 3108 if (strcmp(kdfname, "bcrypt") == 0) { 3109 if ((r = sshbuf_get_string(kdf, &salt, &slen)) != 0 || 3110 (r = sshbuf_get_u32(kdf, &rounds)) != 0) 3111 goto out; 3112 if (bcrypt_pbkdf(passphrase, strlen(passphrase), salt, slen, 3113 key, keylen + ivlen, rounds) < 0) { 3114 r = SSH_ERR_INVALID_FORMAT; 3115 goto out; 3116 } 3117 } 3118 3119 /* check that an appropriate amount of auth data is present */ 3120 if (sshbuf_len(decoded) < authlen || 3121 sshbuf_len(decoded) - authlen < encrypted_len) { 3122 r = SSH_ERR_INVALID_FORMAT; 3123 goto out; 3124 } 3125 3126 /* decrypt private portion of key */ 3127 if ((r = sshbuf_reserve(decrypted, encrypted_len, &dp)) != 0 || 3128 (r = cipher_init(&ciphercontext, cipher, key, keylen, 3129 key + keylen, ivlen, 0)) != 0) 3130 goto out; 3131 if ((r = cipher_crypt(ciphercontext, 0, dp, sshbuf_ptr(decoded), 3132 encrypted_len, 0, authlen)) != 0) { 3133 /* an integrity error here indicates an incorrect passphrase */ 3134 if (r == SSH_ERR_MAC_INVALID) 3135 r = SSH_ERR_KEY_WRONG_PASSPHRASE; 3136 goto out; 3137 } 3138 if ((r = sshbuf_consume(decoded, encrypted_len + authlen)) != 0) 3139 goto out; 3140 /* there should be no trailing data */ 3141 if (sshbuf_len(decoded) != 0) { 3142 r = SSH_ERR_INVALID_FORMAT; 3143 goto out; 3144 } 3145 3146 /* check check bytes */ 3147 if ((r = sshbuf_get_u32(decrypted, &check1)) != 0 || 3148 (r = sshbuf_get_u32(decrypted, &check2)) != 0) 3149 goto out; 3150 if (check1 != check2) { 3151 r = SSH_ERR_KEY_WRONG_PASSPHRASE; 3152 goto out; 3153 } 3154 /* success */ 3155 *decryptedp = decrypted; 3156 decrypted = NULL; 3157 *pubkeyp = pubkey; 3158 pubkey = NULL; 3159 r = 0; 3160 out: 3161 cipher_free(ciphercontext); 3162 free(ciphername); 3163 free(kdfname); 3164 sshkey_free(pubkey); 3165 if (salt != NULL) { 3166 explicit_bzero(salt, slen); 3167 free(salt); 3168 } 3169 if (key != NULL) { 3170 explicit_bzero(key, keylen + ivlen); 3171 free(key); 3172 } 3173 sshbuf_free(kdf); 3174 sshbuf_free(decrypted); 3175 return r; 3176 } 3177 3178 static int 3179 sshkey_parse_private2(struct sshbuf *blob, int type, const char *passphrase, 3180 struct sshkey **keyp, char **commentp) 3181 { 3182 char *comment = NULL; 3183 int r = SSH_ERR_INTERNAL_ERROR; 3184 struct sshbuf *decoded = NULL, *decrypted = NULL; 3185 struct sshkey *k = NULL, *pubkey = NULL; 3186 3187 if (keyp != NULL) 3188 *keyp = NULL; 3189 if (commentp != NULL) 3190 *commentp = NULL; 3191 3192 /* Undo base64 encoding and decrypt the private section */ 3193 if ((r = private2_uudecode(blob, &decoded)) != 0 || 3194 (r = private2_decrypt(decoded, passphrase, 3195 &decrypted, &pubkey)) != 0) 3196 goto out; 3197 3198 if (type != KEY_UNSPEC && 3199 sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) { 3200 r = SSH_ERR_KEY_TYPE_MISMATCH; 3201 goto out; 3202 } 3203 3204 /* Load the private key and comment */ 3205 if ((r = sshkey_private_deserialize(decrypted, &k)) != 0 || 3206 (r = sshbuf_get_cstring(decrypted, &comment, NULL)) != 0) 3207 goto out; 3208 3209 /* Check deterministic padding after private section */ 3210 if ((r = private2_check_padding(decrypted)) != 0) 3211 goto out; 3212 3213 /* Check that the public key in the envelope matches the private key */ 3214 if (!sshkey_equal(pubkey, k)) { 3215 r = SSH_ERR_INVALID_FORMAT; 3216 goto out; 3217 } 3218 3219 /* success */ 3220 r = 0; 3221 if (keyp != NULL) { 3222 *keyp = k; 3223 k = NULL; 3224 } 3225 if (commentp != NULL) { 3226 *commentp = comment; 3227 comment = NULL; 3228 } 3229 out: 3230 free(comment); 3231 sshbuf_free(decoded); 3232 sshbuf_free(decrypted); 3233 sshkey_free(k); 3234 sshkey_free(pubkey); 3235 return r; 3236 } 3237 3238 static int 3239 sshkey_parse_private2_pubkey(struct sshbuf *blob, int type, 3240 struct sshkey **keyp) 3241 { 3242 int r = SSH_ERR_INTERNAL_ERROR; 3243 struct sshbuf *decoded = NULL; 3244 struct sshkey *pubkey = NULL; 3245 u_int nkeys = 0; 3246 3247 if (keyp != NULL) 3248 *keyp = NULL; 3249 3250 if ((r = private2_uudecode(blob, &decoded)) != 0) 3251 goto out; 3252 /* parse public key from unencrypted envelope */ 3253 if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 || 3254 (r = sshbuf_skip_string(decoded)) != 0 || /* cipher */ 3255 (r = sshbuf_skip_string(decoded)) != 0 || /* KDF alg */ 3256 (r = sshbuf_skip_string(decoded)) != 0 || /* KDF hint */ 3257 (r = sshbuf_get_u32(decoded, &nkeys)) != 0) 3258 goto out; 3259 3260 if (nkeys != 1) { 3261 /* XXX only one key supported at present */ 3262 r = SSH_ERR_INVALID_FORMAT; 3263 goto out; 3264 } 3265 3266 /* Parse the public key */ 3267 if ((r = sshkey_froms(decoded, &pubkey)) != 0) 3268 goto out; 3269 3270 if (type != KEY_UNSPEC && 3271 sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) { 3272 r = SSH_ERR_KEY_TYPE_MISMATCH; 3273 goto out; 3274 } 3275 3276 /* success */ 3277 r = 0; 3278 if (keyp != NULL) { 3279 *keyp = pubkey; 3280 pubkey = NULL; 3281 } 3282 out: 3283 sshbuf_free(decoded); 3284 sshkey_free(pubkey); 3285 return r; 3286 } 3287 3288 #ifdef WITH_OPENSSL 3289 /* convert SSH v2 key to PEM or PKCS#8 format */ 3290 static int 3291 sshkey_private_to_blob_pem_pkcs8(struct sshkey *key, struct sshbuf *buf, 3292 int format, const char *_passphrase, const char *comment) 3293 { 3294 int was_shielded = sshkey_is_shielded(key); 3295 int success, r; 3296 int blen, len = strlen(_passphrase); 3297 u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL; 3298 const EVP_CIPHER *cipher = (len > 0) ? EVP_aes_128_cbc() : NULL; 3299 char *bptr; 3300 BIO *bio = NULL; 3301 struct sshbuf *blob; 3302 EVP_PKEY *pkey = NULL; 3303 3304 if (len > 0 && len <= 4) 3305 return SSH_ERR_PASSPHRASE_TOO_SHORT; 3306 if ((blob = sshbuf_new()) == NULL) 3307 return SSH_ERR_ALLOC_FAIL; 3308 if ((bio = BIO_new(BIO_s_mem())) == NULL) { 3309 r = SSH_ERR_ALLOC_FAIL; 3310 goto out; 3311 } 3312 if ((r = sshkey_unshield_private(key)) != 0) 3313 goto out; 3314 3315 switch (key->type) { 3316 #ifdef OPENSSL_HAS_ECC 3317 case KEY_ECDSA: 3318 if (format == SSHKEY_PRIVATE_PEM) { 3319 success = PEM_write_bio_ECPrivateKey(bio, 3320 EVP_PKEY_get0_EC_KEY(key->pkey), 3321 cipher, passphrase, len, NULL, NULL); 3322 } else { 3323 pkey = key->pkey; 3324 EVP_PKEY_up_ref(key->pkey); 3325 success = 1; 3326 } 3327 break; 3328 #endif 3329 case KEY_RSA: 3330 if (format == SSHKEY_PRIVATE_PEM) { 3331 success = PEM_write_bio_RSAPrivateKey(bio, 3332 EVP_PKEY_get0_RSA(key->pkey), 3333 cipher, passphrase, len, NULL, NULL); 3334 } else { 3335 pkey = key->pkey; 3336 EVP_PKEY_up_ref(key->pkey); 3337 success = 1; 3338 } 3339 break; 3340 #ifdef OPENSSL_HAS_ED25519 3341 case KEY_ED25519: 3342 if (format == SSHKEY_PRIVATE_PEM) { 3343 r = SSH_ERR_INVALID_FORMAT; 3344 goto out; 3345 } else { 3346 pkey = EVP_PKEY_new_raw_private_key(EVP_PKEY_ED25519, 3347 NULL, key->ed25519_sk, 3348 ED25519_SK_SZ - ED25519_PK_SZ); 3349 success = pkey != NULL; 3350 } 3351 break; 3352 #endif 3353 default: 3354 success = 0; 3355 break; 3356 } 3357 if (success == 0) { 3358 r = SSH_ERR_LIBCRYPTO_ERROR; 3359 goto out; 3360 } 3361 if (format == SSHKEY_PRIVATE_PKCS8) { 3362 if ((success = PEM_write_bio_PrivateKey(bio, pkey, cipher, 3363 passphrase, len, NULL, NULL)) == 0) { 3364 r = SSH_ERR_LIBCRYPTO_ERROR; 3365 goto out; 3366 } 3367 } 3368 if ((blen = BIO_get_mem_data(bio, &bptr)) <= 0) { 3369 r = SSH_ERR_INTERNAL_ERROR; 3370 goto out; 3371 } 3372 if ((r = sshbuf_put(blob, bptr, blen)) != 0) 3373 goto out; 3374 r = 0; 3375 out: 3376 if (was_shielded) 3377 r = sshkey_shield_private(key); 3378 if (r == 0) 3379 r = sshbuf_putb(buf, blob); 3380 3381 EVP_PKEY_free(pkey); 3382 sshbuf_free(blob); 3383 BIO_free(bio); 3384 return r; 3385 } 3386 #endif /* WITH_OPENSSL */ 3387 3388 /* Serialise "key" to buffer "blob" */ 3389 int 3390 sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob, 3391 const char *passphrase, const char *comment, 3392 int format, const char *openssh_format_cipher, int openssh_format_rounds) 3393 { 3394 switch (key->type) { 3395 #ifdef WITH_OPENSSL 3396 case KEY_ECDSA: 3397 case KEY_RSA: 3398 case KEY_ED25519: 3399 break; /* see below */ 3400 #else /* WITH_OPENSSL */ 3401 case KEY_ED25519: 3402 #endif /* WITH_OPENSSL */ 3403 case KEY_ED25519_SK: 3404 #ifdef WITH_OPENSSL 3405 case KEY_ECDSA_SK: 3406 #endif /* WITH_OPENSSL */ 3407 case KEY_MLDSA44_ED25519: 3408 return sshkey_private_to_blob2(key, blob, passphrase, 3409 comment, openssh_format_cipher, openssh_format_rounds); 3410 default: 3411 return SSH_ERR_KEY_TYPE_UNKNOWN; 3412 } 3413 3414 #ifdef WITH_OPENSSL 3415 switch (format) { 3416 case SSHKEY_PRIVATE_OPENSSH: 3417 return sshkey_private_to_blob2(key, blob, passphrase, 3418 comment, openssh_format_cipher, openssh_format_rounds); 3419 case SSHKEY_PRIVATE_PEM: 3420 case SSHKEY_PRIVATE_PKCS8: 3421 return sshkey_private_to_blob_pem_pkcs8(key, blob, 3422 format, passphrase, comment); 3423 default: 3424 return SSH_ERR_INVALID_ARGUMENT; 3425 } 3426 #endif /* WITH_OPENSSL */ 3427 } 3428 3429 #ifdef WITH_OPENSSL 3430 static int 3431 translate_libcrypto_error(unsigned long pem_err) 3432 { 3433 int pem_reason = ERR_GET_REASON(pem_err); 3434 3435 switch (ERR_GET_LIB(pem_err)) { 3436 case ERR_LIB_PEM: 3437 switch (pem_reason) { 3438 case PEM_R_BAD_PASSWORD_READ: 3439 #ifdef PEM_R_PROBLEMS_GETTING_PASSWORD 3440 case PEM_R_PROBLEMS_GETTING_PASSWORD: 3441 #endif 3442 #ifdef PEM_R_BAD_DECRYPT 3443 case PEM_R_BAD_DECRYPT: 3444 #endif 3445 return SSH_ERR_KEY_WRONG_PASSPHRASE; 3446 default: 3447 return SSH_ERR_INVALID_FORMAT; 3448 } 3449 case ERR_LIB_EVP: 3450 switch (pem_reason) { 3451 #ifdef EVP_R_BAD_DECRYPT 3452 case EVP_R_BAD_DECRYPT: 3453 return SSH_ERR_KEY_WRONG_PASSPHRASE; 3454 #endif 3455 #ifdef EVP_R_BN_DECODE_ERROR 3456 case EVP_R_BN_DECODE_ERROR: 3457 #endif 3458 case EVP_R_DECODE_ERROR: 3459 #ifdef EVP_R_PRIVATE_KEY_DECODE_ERROR 3460 case EVP_R_PRIVATE_KEY_DECODE_ERROR: 3461 #endif 3462 return SSH_ERR_INVALID_FORMAT; 3463 default: 3464 return SSH_ERR_LIBCRYPTO_ERROR; 3465 } 3466 case ERR_LIB_ASN1: 3467 #ifdef ERR_LIB_OSSL_DECODER 3468 case ERR_LIB_OSSL_DECODER: 3469 #endif 3470 return SSH_ERR_INVALID_FORMAT; 3471 } 3472 return SSH_ERR_LIBCRYPTO_ERROR; 3473 } 3474 3475 static void 3476 clear_libcrypto_errors(void) 3477 { 3478 while (ERR_get_error() != 0) 3479 ; 3480 } 3481 3482 /* 3483 * Translate OpenSSL error codes to determine whether 3484 * passphrase is required/incorrect. 3485 */ 3486 static int 3487 convert_libcrypto_error(void) 3488 { 3489 /* 3490 * Some password errors are reported at the beginning 3491 * of the error queue. 3492 */ 3493 if (translate_libcrypto_error(ERR_peek_error()) == 3494 SSH_ERR_KEY_WRONG_PASSPHRASE) 3495 return SSH_ERR_KEY_WRONG_PASSPHRASE; 3496 return translate_libcrypto_error(ERR_peek_last_error()); 3497 } 3498 3499 static int 3500 pem_passphrase_cb(char *buf, int size, int rwflag, void *u) 3501 { 3502 char *p = (char *)u; 3503 size_t len; 3504 3505 if (p == NULL || (len = strlen(p)) == 0) 3506 return -1; 3507 if (size < 0 || len > (size_t)size) 3508 return -1; 3509 memcpy(buf, p, len); 3510 return (int)len; 3511 } 3512 3513 static int 3514 sshkey_parse_private_pem_fileblob(struct sshbuf *blob, int type, 3515 const char *passphrase, struct sshkey **keyp) 3516 { 3517 EVP_PKEY *pk = NULL; 3518 struct sshkey *prv = NULL; 3519 BIO *bio = NULL; 3520 int r; 3521 RSA *rsa = NULL; 3522 EC_KEY *ecdsa = NULL; 3523 3524 if (keyp != NULL) 3525 *keyp = NULL; 3526 3527 if ((bio = BIO_new(BIO_s_mem())) == NULL || sshbuf_len(blob) > INT_MAX) 3528 return SSH_ERR_ALLOC_FAIL; 3529 if (BIO_write(bio, sshbuf_ptr(blob), sshbuf_len(blob)) != 3530 (int)sshbuf_len(blob)) { 3531 r = SSH_ERR_ALLOC_FAIL; 3532 goto out; 3533 } 3534 3535 clear_libcrypto_errors(); 3536 if ((pk = PEM_read_bio_PrivateKey(bio, NULL, pem_passphrase_cb, 3537 (char *)passphrase)) == NULL) { 3538 /* 3539 * libcrypto may return various ASN.1 errors when attempting 3540 * to parse a key with an incorrect passphrase. 3541 * Treat all format errors as "incorrect passphrase" if a 3542 * passphrase was supplied. 3543 */ 3544 if (passphrase != NULL && *passphrase != '\0') 3545 r = SSH_ERR_KEY_WRONG_PASSPHRASE; 3546 else 3547 r = convert_libcrypto_error(); 3548 goto out; 3549 } 3550 if (EVP_PKEY_base_id(pk) == EVP_PKEY_RSA && 3551 (type == KEY_UNSPEC || type == KEY_RSA)) { 3552 if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) { 3553 r = SSH_ERR_ALLOC_FAIL; 3554 goto out; 3555 } 3556 if ((rsa = EVP_PKEY_get1_RSA(pk)) == NULL) { 3557 r = SSH_ERR_LIBCRYPTO_ERROR; 3558 goto out; 3559 } 3560 prv->type = KEY_RSA; 3561 #ifdef DEBUG_PK 3562 RSA_print_fp(stderr, rsa, 8); 3563 #endif 3564 if (RSA_blinding_on(rsa, NULL) != 1 || 3565 EVP_PKEY_set1_RSA(pk, rsa) != 1) { 3566 r = SSH_ERR_LIBCRYPTO_ERROR; 3567 goto out; 3568 } 3569 EVP_PKEY_up_ref(pk); 3570 prv->pkey = pk; 3571 if ((r = sshkey_check_rsa_length(prv, 0)) != 0) 3572 goto out; 3573 #ifdef OPENSSL_HAS_ECC 3574 } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_EC && 3575 (type == KEY_UNSPEC || type == KEY_ECDSA)) { 3576 if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) { 3577 r = SSH_ERR_ALLOC_FAIL; 3578 goto out; 3579 } 3580 if ((prv->ecdsa_nid = sshkey_ecdsa_fixup_group(pk)) == -1 || 3581 (ecdsa = EVP_PKEY_get1_EC_KEY(pk)) == NULL) { 3582 r = SSH_ERR_LIBCRYPTO_ERROR; 3583 goto out; 3584 } 3585 prv->type = KEY_ECDSA; 3586 if (sshkey_curve_nid_to_name(prv->ecdsa_nid) == NULL || 3587 sshkey_ec_validate_public(EC_KEY_get0_group(ecdsa), 3588 EC_KEY_get0_public_key(ecdsa)) != 0 || 3589 sshkey_ec_validate_private(ecdsa) != 0) { 3590 r = SSH_ERR_INVALID_FORMAT; 3591 goto out; 3592 } 3593 EVP_PKEY_up_ref(pk); 3594 prv->pkey = pk; 3595 #ifdef DEBUG_PK 3596 if (prv != NULL && prv->pkey != NULL) 3597 sshkey_dump_ec_key(EVP_PKEY_get0_EC_KEY(prv->pkey)); 3598 #endif 3599 #endif /* OPENSSL_HAS_ECC */ 3600 #ifdef OPENSSL_HAS_ED25519 3601 } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_ED25519 && 3602 (type == KEY_UNSPEC || type == KEY_ED25519)) { 3603 size_t len; 3604 3605 if ((prv = sshkey_new(KEY_UNSPEC)) == NULL || 3606 (prv->ed25519_sk = calloc(1, ED25519_SK_SZ)) == NULL || 3607 (prv->ed25519_pk = calloc(1, ED25519_PK_SZ)) == NULL) { 3608 r = SSH_ERR_ALLOC_FAIL; 3609 goto out; 3610 } 3611 prv->type = KEY_ED25519; 3612 len = ED25519_PK_SZ; 3613 if (!EVP_PKEY_get_raw_public_key(pk, prv->ed25519_pk, &len)) { 3614 r = SSH_ERR_LIBCRYPTO_ERROR; 3615 goto out; 3616 } 3617 if (len != ED25519_PK_SZ) { 3618 r = SSH_ERR_INVALID_FORMAT; 3619 goto out; 3620 } 3621 len = ED25519_SK_SZ - ED25519_PK_SZ; 3622 if (!EVP_PKEY_get_raw_private_key(pk, prv->ed25519_sk, &len)) { 3623 r = SSH_ERR_LIBCRYPTO_ERROR; 3624 goto out; 3625 } 3626 if (len != ED25519_SK_SZ - ED25519_PK_SZ) { 3627 r = SSH_ERR_INVALID_FORMAT; 3628 goto out; 3629 } 3630 /* Append the public key to our private key */ 3631 memcpy(prv->ed25519_sk + (ED25519_SK_SZ - ED25519_PK_SZ), 3632 prv->ed25519_pk, ED25519_PK_SZ); 3633 #ifdef DEBUG_PK 3634 sshbuf_dump_data(prv->ed25519_sk, ED25519_SK_SZ, stderr); 3635 #endif 3636 #endif /* OPENSSL_HAS_ED25519 */ 3637 } else { 3638 r = SSH_ERR_INVALID_FORMAT; 3639 goto out; 3640 } 3641 r = 0; 3642 if (keyp != NULL) { 3643 *keyp = prv; 3644 prv = NULL; 3645 } 3646 out: 3647 BIO_free(bio); 3648 EVP_PKEY_free(pk); 3649 RSA_free(rsa); 3650 #ifdef OPENSSL_HAS_ECC 3651 EC_KEY_free(ecdsa); 3652 #endif 3653 sshkey_free(prv); 3654 return r; 3655 } 3656 #endif /* WITH_OPENSSL */ 3657 3658 int 3659 sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type, 3660 const char *passphrase, struct sshkey **keyp, char **commentp) 3661 { 3662 int r = SSH_ERR_INTERNAL_ERROR; 3663 3664 if (keyp != NULL) 3665 *keyp = NULL; 3666 if (commentp != NULL) 3667 *commentp = NULL; 3668 3669 r = sshkey_parse_private2(blob, type, passphrase, keyp, commentp); 3670 /* Only fallback to PEM parser if a format error occurred. */ 3671 if (r != SSH_ERR_INVALID_FORMAT) 3672 return r; 3673 #ifdef WITH_OPENSSL 3674 return sshkey_parse_private_pem_fileblob(blob, type, 3675 passphrase, keyp); 3676 #else 3677 return SSH_ERR_INVALID_FORMAT; 3678 #endif /* WITH_OPENSSL */ 3679 } 3680 3681 int 3682 sshkey_parse_private_fileblob(struct sshbuf *buffer, const char *passphrase, 3683 struct sshkey **keyp, char **commentp) 3684 { 3685 if (keyp != NULL) 3686 *keyp = NULL; 3687 if (commentp != NULL) 3688 *commentp = NULL; 3689 3690 return sshkey_parse_private_fileblob_type(buffer, KEY_UNSPEC, 3691 passphrase, keyp, commentp); 3692 } 3693 3694 void 3695 sshkey_sig_details_free(struct sshkey_sig_details *details) 3696 { 3697 freezero(details, sizeof(*details)); 3698 } 3699 3700 int 3701 sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob, int type, 3702 struct sshkey **pubkeyp) 3703 { 3704 int r = SSH_ERR_INTERNAL_ERROR; 3705 3706 if (pubkeyp != NULL) 3707 *pubkeyp = NULL; 3708 /* only new-format private keys bundle a public key inside */ 3709 if ((r = sshkey_parse_private2_pubkey(blob, type, pubkeyp)) != 0) 3710 return r; 3711 return 0; 3712 } 3713