1 /* $NetBSD: sshkey.c,v 1.39 2026/10/07 17:32:09 christos Exp $ */ 2 /* $OpenBSD: sshkey.c,v 1.165 2026/10/01 07:07:49 djm Exp $ */ 3 4 /* 5 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 6 * Copyright (c) 2008 Alexander von Gernler. All rights reserved. 7 * Copyright (c) 2010,2011 Damien Miller. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 #include "includes.h" 30 __RCSID("$NetBSD: sshkey.c,v 1.39 2026/10/07 17:32:09 christos Exp $"); 31 32 #include <sys/types.h> 33 #include <sys/mman.h> 34 #include <netinet/in.h> 35 36 #ifdef WITH_OPENSSL 37 #include <openssl/bn.h> 38 #include <openssl/evp.h> 39 #include <openssl/err.h> 40 #include <openssl/pem.h> 41 #endif 42 43 #ifndef MAP_CONCEAL 44 #define MAP_CONCEAL 0 45 #endif 46 47 #include "crypto_api.h" 48 49 #include <errno.h> 50 #include <limits.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 #include <resolv.h> 55 #include <time.h> 56 #include <util.h> 57 58 #include "ssh2.h" 59 #include "ssherr.h" 60 #include "misc.h" 61 #include "sshbuf.h" 62 #include "cipher.h" 63 #include "digest.h" 64 #define SSHKEY_INTERNAL 65 #include "sshkey.h" 66 #include "match.h" 67 #include "ssh-sk.h" 68 #include "ssh-pkcs11.h" 69 70 71 /* openssh private key file format */ 72 #define MARK_BEGIN "-----BEGIN OPENSSH PRIVATE KEY-----\n" 73 #define MARK_END "-----END OPENSSH PRIVATE KEY-----\n" 74 #define MARK_BEGIN_LEN (sizeof(MARK_BEGIN) - 1) 75 #define MARK_END_LEN (sizeof(MARK_END) - 1) 76 #define KDFNAME "bcrypt" 77 #define AUTH_MAGIC "openssh-key-v1" 78 #define SALT_LEN 16 79 #define DEFAULT_CIPHERNAME "aes256-ctr" 80 #define DEFAULT_ROUNDS 32 81 #define MAX_KDF_ROUNDS (1<<20) 82 83 /* 84 * Constants relating to "shielding" support; protection of keys expected 85 * to remain in memory for long durations 86 */ 87 #define SSHKEY_SHIELD_PREKEY_LEN (16 * 1024) 88 #define SSHKEY_SHIELD_CIPHER "aes256-ctr" /* XXX want AES-EME* */ 89 #define SSHKEY_SHIELD_PREKEY_HASH SSH_DIGEST_SHA512 90 91 static int sshkey_from_blob_internal(struct sshbuf *buf, 92 struct sshkey **keyp, int allow_cert, 93 const char *alg_allowlist, const char *ca_sigalg_allowlist); 94 95 /* Supported key types */ 96 extern const struct sshkey_impl sshkey_ed25519_impl; 97 extern const struct sshkey_impl sshkey_ed25519_cert_impl; 98 extern const struct sshkey_impl sshkey_ed25519_sk_impl; 99 extern const struct sshkey_impl sshkey_ed25519_sk_cert_impl; 100 extern const struct sshkey_impl sshkey_mldsa44_ed25519_impl; 101 extern const struct sshkey_impl sshkey_mldsa44_ed25519_cert_impl; 102 #ifdef WITH_OPENSSL 103 extern const struct sshkey_impl sshkey_ecdsa_sk_impl; 104 extern const struct sshkey_impl sshkey_ecdsa_sk_cert_impl; 105 extern const struct sshkey_impl sshkey_ecdsa_sk_webauthn_impl; 106 extern const struct sshkey_impl sshkey_ecdsa_sk_webauthn_cert_impl; 107 extern const struct sshkey_impl sshkey_ecdsa_nistp256_impl; 108 extern const struct sshkey_impl sshkey_ecdsa_nistp256_cert_impl; 109 extern const struct sshkey_impl sshkey_ecdsa_nistp384_impl; 110 extern const struct sshkey_impl sshkey_ecdsa_nistp384_cert_impl; 111 extern const struct sshkey_impl sshkey_ecdsa_nistp521_impl; 112 extern const struct sshkey_impl sshkey_ecdsa_nistp521_cert_impl; 113 extern const struct sshkey_impl sshkey_rsa_impl; 114 extern const struct sshkey_impl sshkey_rsa_cert_impl; 115 extern const struct sshkey_impl sshkey_rsa_sha256_impl; 116 extern const struct sshkey_impl sshkey_rsa_sha256_cert_impl; 117 extern const struct sshkey_impl sshkey_rsa_sha512_impl; 118 extern const struct sshkey_impl sshkey_rsa_sha512_cert_impl; 119 #endif /* WITH_OPENSSL */ 120 121 const struct sshkey_impl * const keyimpls[] = { 122 &sshkey_ed25519_impl, 123 &sshkey_ed25519_cert_impl, 124 &sshkey_ed25519_sk_impl, 125 &sshkey_ed25519_sk_cert_impl, 126 &sshkey_mldsa44_ed25519_impl, 127 &sshkey_mldsa44_ed25519_cert_impl, 128 #ifdef WITH_OPENSSL 129 &sshkey_ecdsa_nistp256_impl, 130 &sshkey_ecdsa_nistp256_cert_impl, 131 &sshkey_ecdsa_nistp384_impl, 132 &sshkey_ecdsa_nistp384_cert_impl, 133 &sshkey_ecdsa_nistp521_impl, 134 &sshkey_ecdsa_nistp521_cert_impl, 135 &sshkey_ecdsa_sk_impl, 136 &sshkey_ecdsa_sk_cert_impl, 137 &sshkey_ecdsa_sk_webauthn_impl, 138 &sshkey_ecdsa_sk_webauthn_cert_impl, 139 &sshkey_rsa_impl, 140 &sshkey_rsa_cert_impl, 141 &sshkey_rsa_sha256_impl, 142 &sshkey_rsa_sha256_cert_impl, 143 &sshkey_rsa_sha512_impl, 144 &sshkey_rsa_sha512_cert_impl, 145 #endif /* WITH_OPENSSL */ 146 NULL 147 }; 148 149 static const struct sshkey_impl * 150 sshkey_impl_from_type(int type) 151 { 152 int i; 153 154 for (i = 0; keyimpls[i] != NULL; i++) { 155 if (keyimpls[i]->type == type) 156 return keyimpls[i]; 157 } 158 return NULL; 159 } 160 161 static const struct sshkey_impl * 162 sshkey_impl_from_type_nid(int type, int nid) 163 { 164 int i; 165 166 for (i = 0; keyimpls[i] != NULL; i++) { 167 if (keyimpls[i]->type == type && 168 (keyimpls[i]->nid == 0 || keyimpls[i]->nid == nid)) 169 return keyimpls[i]; 170 } 171 return NULL; 172 } 173 174 static const struct sshkey_impl * 175 sshkey_impl_from_key(const struct sshkey *k) 176 { 177 if (k == NULL) 178 return NULL; 179 return sshkey_impl_from_type_nid(k->type, k->ecdsa_nid); 180 } 181 182 const char * 183 sshkey_type(const struct sshkey *k) 184 { 185 const struct sshkey_impl *impl; 186 187 if ((impl = sshkey_impl_from_key(k)) == NULL) 188 return "unknown"; 189 return impl->shortname; 190 } 191 192 static const char * 193 sshkey_ssh_name_from_type_nid(int type, int nid) 194 { 195 const struct sshkey_impl *impl; 196 197 if ((impl = sshkey_impl_from_type_nid(type, nid)) == NULL) 198 return "ssh-unknown"; 199 return impl->name; 200 } 201 202 int 203 sshkey_type_is_cert(int type) 204 { 205 const struct sshkey_impl *impl; 206 207 if ((impl = sshkey_impl_from_type(type)) == NULL) 208 return 0; 209 return impl->cert; 210 } 211 212 const char * 213 sshkey_ssh_name(const struct sshkey *k) 214 { 215 return sshkey_ssh_name_from_type_nid(k->type, k->ecdsa_nid); 216 } 217 218 const char * 219 sshkey_ssh_name_plain(const struct sshkey *k) 220 { 221 return sshkey_ssh_name_from_type_nid(sshkey_type_plain(k->type), 222 k->ecdsa_nid); 223 } 224 225 static int 226 type_from_name(const char *name, int allow_short) 227 { 228 int i; 229 const struct sshkey_impl *impl; 230 231 for (i = 0; keyimpls[i] != NULL; i++) { 232 impl = keyimpls[i]; 233 if (impl->name != NULL && strcmp(name, impl->name) == 0) 234 return impl->type; 235 /* Only allow shortname matches for plain key types */ 236 if (allow_short && !impl->cert && impl->shortname != NULL && 237 strcasecmp(impl->shortname, name) == 0) 238 return impl->type; 239 } 240 return KEY_UNSPEC; 241 } 242 243 int 244 sshkey_type_from_name(const char *name) 245 { 246 return type_from_name(name, 0); 247 } 248 249 int 250 sshkey_type_from_shortname(const char *name) 251 { 252 return type_from_name(name, 1); 253 } 254 255 static int 256 key_type_is_ecdsa_variant(int type) 257 { 258 switch (type) { 259 case KEY_ECDSA: 260 case KEY_ECDSA_CERT: 261 case KEY_ECDSA_SK: 262 case KEY_ECDSA_SK_CERT: 263 return 1; 264 } 265 return 0; 266 } 267 268 int 269 sshkey_ecdsa_nid_from_name(const char *name) 270 { 271 int i; 272 273 for (i = 0; keyimpls[i] != NULL; i++) { 274 if (!key_type_is_ecdsa_variant(keyimpls[i]->type)) 275 continue; 276 if (keyimpls[i]->name != NULL && 277 strcmp(name, keyimpls[i]->name) == 0) 278 return keyimpls[i]->nid; 279 } 280 return -1; 281 } 282 283 int 284 sshkey_match_keyname_to_sigalgs(const char *keyname, const char *sigalgs) 285 { 286 int ktype; 287 288 if (sigalgs == NULL || *sigalgs == '\0' || 289 (ktype = sshkey_type_from_name(keyname)) == KEY_UNSPEC) 290 return 0; 291 else if (ktype == KEY_RSA) { 292 return match_pattern_list("ssh-rsa", sigalgs, 0) == 1 || 293 match_pattern_list("rsa-sha2-256", sigalgs, 0) == 1 || 294 match_pattern_list("rsa-sha2-512", sigalgs, 0) == 1; 295 } else if (ktype == KEY_RSA_CERT) { 296 return match_pattern_list("ssh-rsa-cert-v01 (at) openssh.com", 297 sigalgs, 0) == 1 || 298 match_pattern_list("rsa-sha2-256-cert-v01 (at) openssh.com", 299 sigalgs, 0) == 1 || 300 match_pattern_list("rsa-sha2-512-cert-v01 (at) openssh.com", 301 sigalgs, 0) == 1; 302 } else if (ktype == KEY_ECDSA_SK) { 303 return match_pattern_list("sk-ecdsa-sha2-nistp256 (at) openssh.com", 304 sigalgs, 0) == 1 || match_pattern_list( 305 "webauthn-sk-ecdsa-sha2-nistp256 (at) openssh.com", 306 sigalgs, 0) == 1; 307 } else if (ktype == KEY_ECDSA_SK_CERT) { 308 return match_pattern_list( 309 "sk-ecdsa-sha2-nistp256-cert-v01 (at) openssh.com", 310 sigalgs, 0) == 1 || match_pattern_list( 311 "webauthn-sk-ecdsa-sha2-nistp256-cert-v01 (at) openssh.com", 312 sigalgs, 0) == 1; 313 } else 314 return match_pattern_list(keyname, sigalgs, 0) == 1; 315 } 316 317 char * 318 sshkey_alg_list(int certs_only, int plain_only, int include_sigonly, char sep) 319 { 320 char *ret = NULL; 321 size_t i; 322 const struct sshkey_impl *impl; 323 char sep_str[2] = {sep, '\0'}; 324 325 for (i = 0; keyimpls[i] != NULL; i++) { 326 impl = keyimpls[i]; 327 if (impl->name == NULL) 328 continue; 329 if (!include_sigonly && impl->sigonly) 330 continue; 331 if ((certs_only && !impl->cert) || (plain_only && impl->cert)) 332 continue; 333 xextendf(&ret, sep_str, "%s", impl->name); 334 } 335 return ret; 336 } 337 338 int 339 sshkey_names_valid2(const char *names, int allow_wildcard, int plain_only) 340 { 341 char *s, *cp, *p; 342 const struct sshkey_impl *impl; 343 int i, type; 344 345 if (names == NULL || strcmp(names, "") == 0) 346 return 0; 347 if ((s = cp = strdup(names)) == NULL) 348 return 0; 349 for ((p = strsep(&cp, ",")); p && *p != '\0'; 350 (p = strsep(&cp, ","))) { 351 type = sshkey_type_from_name(p); 352 if (type == KEY_UNSPEC) { 353 if (allow_wildcard) { 354 /* 355 * Try matching key types against the string. 356 * If any has a positive or negative match then 357 * the component is accepted. 358 */ 359 impl = NULL; 360 for (i = 0; keyimpls[i] != NULL; i++) { 361 if (match_pattern_list( 362 keyimpls[i]->name, p, 0) != 0) { 363 impl = keyimpls[i]; 364 break; 365 } 366 } 367 if (impl != NULL) 368 continue; 369 } 370 free(s); 371 return 0; 372 } else if (plain_only && sshkey_type_is_cert(type)) { 373 free(s); 374 return 0; 375 } 376 } 377 free(s); 378 return 1; 379 } 380 381 u_int 382 sshkey_size(const struct sshkey *k) 383 { 384 const struct sshkey_impl *impl; 385 386 if ((impl = sshkey_impl_from_key(k)) == NULL) 387 return 0; 388 if (impl->funcs->size != NULL) 389 return impl->funcs->size(k); 390 return impl->keybits; 391 } 392 393 static int 394 sshkey_type_is_valid_ca(int type) 395 { 396 const struct sshkey_impl *impl; 397 398 if ((impl = sshkey_impl_from_type(type)) == NULL) 399 return 0; 400 /* All non-certificate types may act as CAs */ 401 return !impl->cert; 402 } 403 404 int 405 sshkey_is_cert(const struct sshkey *k) 406 { 407 if (k == NULL) 408 return 0; 409 return sshkey_type_is_cert(k->type); 410 } 411 412 int 413 sshkey_is_sk(const struct sshkey *k) 414 { 415 if (k == NULL) 416 return 0; 417 switch (sshkey_type_plain(k->type)) { 418 case KEY_ECDSA_SK: 419 case KEY_ED25519_SK: 420 return 1; 421 default: 422 return 0; 423 } 424 } 425 426 /* Return the cert-less equivalent to a certified key type */ 427 int 428 sshkey_type_plain(int type) 429 { 430 switch (type) { 431 case KEY_RSA_CERT: 432 return KEY_RSA; 433 case KEY_ECDSA_CERT: 434 return KEY_ECDSA; 435 case KEY_ECDSA_SK_CERT: 436 return KEY_ECDSA_SK; 437 case KEY_ED25519_CERT: 438 return KEY_ED25519; 439 case KEY_MLDSA44_ED25519_CERT: 440 return KEY_MLDSA44_ED25519; 441 case KEY_ED25519_SK_CERT: 442 return KEY_ED25519_SK; 443 default: 444 return type; 445 } 446 } 447 448 /* Return the cert equivalent to a plain key type */ 449 static int 450 sshkey_type_certified(int type) 451 { 452 switch (type) { 453 case KEY_RSA: 454 return KEY_RSA_CERT; 455 case KEY_ECDSA: 456 return KEY_ECDSA_CERT; 457 case KEY_ECDSA_SK: 458 return KEY_ECDSA_SK_CERT; 459 case KEY_ED25519: 460 return KEY_ED25519_CERT; 461 case KEY_MLDSA44_ED25519: 462 return KEY_MLDSA44_ED25519_CERT; 463 case KEY_ED25519_SK: 464 return KEY_ED25519_SK_CERT; 465 default: 466 return -1; 467 } 468 } 469 470 #ifdef WITH_OPENSSL 471 static const EVP_MD * 472 ssh_digest_to_md(int hash_alg) 473 { 474 switch (hash_alg) { 475 case SSH_DIGEST_SHA1: 476 return EVP_sha1(); 477 case SSH_DIGEST_SHA256: 478 return EVP_sha256(); 479 case SSH_DIGEST_SHA384: 480 return EVP_sha384(); 481 case SSH_DIGEST_SHA512: 482 return EVP_sha512(); 483 } 484 return NULL; 485 } 486 487 int 488 sshkey_pkey_digest_sign(EVP_PKEY *pkey, int hash_alg, u_char **sigp, 489 size_t *lenp, const u_char *data, size_t datalen) 490 { 491 EVP_MD_CTX *ctx = NULL; 492 u_char *sig = NULL; 493 int ret; 494 size_t slen; 495 const EVP_MD *evpmd; 496 497 *sigp = NULL; 498 *lenp = 0; 499 500 slen = EVP_PKEY_size(pkey); 501 if (slen <= 0 || slen > SSHBUF_MAX_BIGNUM || 502 (evpmd = ssh_digest_to_md(hash_alg)) == NULL) 503 return SSH_ERR_INVALID_ARGUMENT; 504 505 if ((sig = malloc(slen)) == NULL) 506 return SSH_ERR_ALLOC_FAIL; 507 508 if ((ctx = EVP_MD_CTX_new()) == NULL) { 509 ret = SSH_ERR_ALLOC_FAIL; 510 goto out; 511 } 512 if (EVP_DigestSignInit(ctx, NULL, evpmd, NULL, pkey) != 1 || 513 EVP_DigestSign(ctx, sig, &slen, data, datalen) != 1) { 514 ret = SSH_ERR_LIBCRYPTO_ERROR; 515 goto out; 516 } 517 518 *sigp = sig; 519 *lenp = slen; 520 /* Now owned by the caller */ 521 sig = NULL; 522 ret = 0; 523 524 out: 525 EVP_MD_CTX_free(ctx); 526 free(sig); 527 return ret; 528 } 529 530 int 531 sshkey_pkey_digest_verify(EVP_PKEY *pkey, int hash_alg, const u_char *data, 532 size_t datalen, u_char *sigbuf, size_t siglen) 533 { 534 EVP_MD_CTX *ctx = NULL; 535 int ret = SSH_ERR_INTERNAL_ERROR; 536 const EVP_MD *evpmd; 537 538 if ((evpmd = ssh_digest_to_md(hash_alg)) == NULL) 539 return SSH_ERR_INVALID_ARGUMENT; 540 if ((ctx = EVP_MD_CTX_new()) == NULL) 541 return SSH_ERR_ALLOC_FAIL; 542 if (EVP_DigestVerifyInit(ctx, NULL, evpmd, NULL, pkey) != 1) { 543 ret = SSH_ERR_LIBCRYPTO_ERROR; 544 goto out; 545 } 546 switch (EVP_DigestVerify(ctx, sigbuf, siglen, data, datalen)) { 547 case 1: 548 ret = 0; 549 break; 550 case 0: 551 ret = SSH_ERR_SIGNATURE_INVALID; 552 break; 553 default: 554 ret = SSH_ERR_LIBCRYPTO_ERROR; 555 break; 556 } 557 558 out: 559 EVP_MD_CTX_free(ctx); 560 return ret; 561 } 562 563 /* XXX: these are really begging for a table-driven approach */ 564 int 565 sshkey_curve_name_to_nid(const char *name) 566 { 567 if (strcmp(name, "nistp256") == 0) 568 return NID_X9_62_prime256v1; 569 else if (strcmp(name, "nistp384") == 0) 570 return NID_secp384r1; 571 else if (strcmp(name, "nistp521") == 0) 572 return NID_secp521r1; 573 else 574 return -1; 575 } 576 577 u_int 578 sshkey_curve_nid_to_bits(int nid) 579 { 580 switch (nid) { 581 case NID_X9_62_prime256v1: 582 return 256; 583 case NID_secp384r1: 584 return 384; 585 case NID_secp521r1: 586 return 521; 587 default: 588 return 0; 589 } 590 } 591 592 int 593 sshkey_ecdsa_bits_to_nid(int bits) 594 { 595 switch (bits) { 596 case 256: 597 return NID_X9_62_prime256v1; 598 case 384: 599 return NID_secp384r1; 600 case 521: 601 return NID_secp521r1; 602 default: 603 return -1; 604 } 605 } 606 607 const char * 608 sshkey_curve_nid_to_name(int nid) 609 { 610 switch (nid) { 611 case NID_X9_62_prime256v1: 612 return "nistp256"; 613 case NID_secp384r1: 614 return "nistp384"; 615 case NID_secp521r1: 616 return "nistp521"; 617 default: 618 return NULL; 619 } 620 } 621 622 int 623 sshkey_ec_nid_to_hash_alg(int nid) 624 { 625 int kbits = sshkey_curve_nid_to_bits(nid); 626 627 if (kbits <= 0) 628 return -1; 629 630 /* RFC5656 section 6.2.1 */ 631 if (kbits <= 256) 632 return SSH_DIGEST_SHA256; 633 else if (kbits <= 384) 634 return SSH_DIGEST_SHA384; 635 else 636 return SSH_DIGEST_SHA512; 637 } 638 #endif /* WITH_OPENSSL */ 639 640 static void 641 cert_free(struct sshkey_cert *cert) 642 { 643 u_int i; 644 645 if (cert == NULL) 646 return; 647 sshbuf_free(cert->certblob); 648 sshbuf_free(cert->critical); 649 sshbuf_free(cert->extensions); 650 free(cert->key_id); 651 for (i = 0; i < cert->nprincipals; i++) 652 free(cert->principals[i]); 653 free(cert->principals); 654 sshkey_free(cert->signature_key); 655 free(cert->signature_type); 656 freezero(cert, sizeof(*cert)); 657 } 658 659 static struct sshkey_cert * 660 cert_new(void) 661 { 662 struct sshkey_cert *cert; 663 664 if ((cert = calloc(1, sizeof(*cert))) == NULL) 665 return NULL; 666 if ((cert->certblob = sshbuf_new()) == NULL || 667 (cert->critical = sshbuf_new()) == NULL || 668 (cert->extensions = sshbuf_new()) == NULL) { 669 cert_free(cert); 670 return NULL; 671 } 672 cert->key_id = NULL; 673 cert->principals = NULL; 674 cert->signature_key = NULL; 675 cert->signature_type = NULL; 676 return cert; 677 } 678 679 struct sshkey * 680 sshkey_new(int type) 681 { 682 struct sshkey *k; 683 const struct sshkey_impl *impl = NULL; 684 685 if (type != KEY_UNSPEC && 686 (impl = sshkey_impl_from_type(type)) == NULL) 687 return NULL; 688 689 /* All non-certificate types may act as CAs */ 690 if ((k = calloc(1, sizeof(*k))) == NULL) 691 return NULL; 692 k->type = type; 693 k->ecdsa_nid = -1; 694 if (impl != NULL && impl->funcs->alloc != NULL) { 695 if (impl->funcs->alloc(k) != 0) { 696 free(k); 697 return NULL; 698 } 699 } 700 if (sshkey_is_cert(k)) { 701 if ((k->cert = cert_new()) == NULL) { 702 sshkey_free(k); 703 return NULL; 704 } 705 } 706 707 return k; 708 } 709 710 /* Frees common FIDO fields */ 711 void 712 sshkey_sk_cleanup(struct sshkey *k) 713 { 714 free(k->sk_application); 715 sshbuf_free(k->sk_key_handle); 716 sshbuf_free(k->sk_reserved); 717 k->sk_application = NULL; 718 k->sk_key_handle = k->sk_reserved = NULL; 719 } 720 721 static int 722 sshkey_prekey_alloc(u_char **prekeyp, size_t len) 723 { 724 u_char *prekey; 725 726 *prekeyp = NULL; 727 if ((prekey = mmap(NULL, len, PROT_READ|PROT_WRITE, 728 MAP_ANON|MAP_PRIVATE|MAP_CONCEAL, -1, 0)) == MAP_FAILED) 729 return SSH_ERR_SYSTEM_ERROR; 730 *prekeyp = prekey; 731 return 0; 732 } 733 734 static void 735 sshkey_prekey_free(void *prekey, size_t len) 736 { 737 if (prekey == NULL) 738 return; 739 munmap(prekey, len); 740 } 741 742 static void 743 sshkey_free_contents(struct sshkey *k) 744 { 745 const struct sshkey_impl *impl; 746 747 if (k == NULL) 748 return; 749 if ((k->flags & SSHKEY_FLAG_EXT) != 0) 750 pkcs11_key_free(k); 751 if ((impl = sshkey_impl_from_type(k->type)) != NULL && 752 impl->funcs->cleanup != NULL) 753 impl->funcs->cleanup(k); 754 if (sshkey_is_cert(k)) 755 cert_free(k->cert); 756 freezero(k->shielded_private, k->shielded_len); 757 sshkey_prekey_free(k->shield_prekey, k->shield_prekey_len); 758 } 759 760 void 761 sshkey_free(struct sshkey *k) 762 { 763 sshkey_free_contents(k); 764 freezero(k, sizeof(*k)); 765 } 766 767 static int 768 cert_compare(struct sshkey_cert *a, struct sshkey_cert *b) 769 { 770 if (a == NULL && b == NULL) 771 return 1; 772 if (a == NULL || b == NULL) 773 return 0; 774 if (sshbuf_len(a->certblob) != sshbuf_len(b->certblob)) 775 return 0; 776 if (timingsafe_bcmp(sshbuf_ptr(a->certblob), sshbuf_ptr(b->certblob), 777 sshbuf_len(a->certblob)) != 0) 778 return 0; 779 return 1; 780 } 781 782 /* Compares FIDO-specific pubkey fields only */ 783 int 784 sshkey_sk_fields_equal(const struct sshkey *a, const struct sshkey *b) 785 { 786 if (a->sk_application == NULL || b->sk_application == NULL) 787 return 0; 788 if (strcmp(a->sk_application, b->sk_application) != 0) 789 return 0; 790 return 1; 791 } 792 793 /* 794 * Compare public portions of key only, allowing comparisons between 795 * certificates and plain keys too. 796 */ 797 int 798 sshkey_equal_public(const struct sshkey *a, const struct sshkey *b) 799 { 800 const struct sshkey_impl *impl; 801 802 if (a == NULL || b == NULL || 803 sshkey_type_plain(a->type) != sshkey_type_plain(b->type)) 804 return 0; 805 if ((impl = sshkey_impl_from_type(a->type)) == NULL) 806 return 0; 807 return impl->funcs->equal(a, b); 808 } 809 810 int 811 sshkey_equal(const struct sshkey *a, const struct sshkey *b) 812 { 813 if (a == NULL || b == NULL || a->type != b->type) 814 return 0; 815 if (sshkey_is_cert(a)) { 816 if (!cert_compare(a->cert, b->cert)) 817 return 0; 818 } 819 return sshkey_equal_public(a, b); 820 } 821 822 823 /* Serialise common FIDO key parts */ 824 int 825 sshkey_serialize_sk(const struct sshkey *key, struct sshbuf *b) 826 { 827 int r; 828 829 if ((r = sshbuf_put_cstring(b, key->sk_application)) != 0) 830 return r; 831 832 return 0; 833 } 834 835 static int 836 to_blob_buf(const struct sshkey *key, struct sshbuf *b, int force_plain, 837 enum sshkey_serialize_rep opts) 838 { 839 int type, ret = SSH_ERR_INTERNAL_ERROR; 840 const char *typename; 841 const struct sshkey_impl *impl; 842 843 if (key == NULL) 844 return SSH_ERR_INVALID_ARGUMENT; 845 846 type = force_plain ? sshkey_type_plain(key->type) : key->type; 847 848 if (sshkey_type_is_cert(type)) { 849 if (key->cert == NULL) 850 return SSH_ERR_EXPECTED_CERT; 851 if (sshbuf_len(key->cert->certblob) == 0) 852 return SSH_ERR_KEY_LACKS_CERTBLOB; 853 /* Use the existing blob */ 854 if ((ret = sshbuf_putb(b, key->cert->certblob)) != 0) 855 return ret; 856 return 0; 857 } 858 if ((impl = sshkey_impl_from_type(type)) == NULL) 859 return SSH_ERR_KEY_TYPE_UNKNOWN; 860 861 typename = sshkey_ssh_name_from_type_nid(type, key->ecdsa_nid); 862 if ((ret = sshbuf_put_cstring(b, typename)) != 0) 863 return ret; 864 return impl->funcs->serialize_public(key, b, opts); 865 } 866 867 int 868 sshkey_putb(const struct sshkey *key, struct sshbuf *b) 869 { 870 return to_blob_buf(key, b, 0, SSHKEY_SERIALIZE_DEFAULT); 871 } 872 873 static int 874 sshkey_puts_opts_internal(const struct sshkey *key, struct sshbuf *b, 875 enum sshkey_serialize_rep opts, int force_plain) 876 { 877 struct sshbuf *tmp; 878 int r; 879 880 if ((tmp = sshbuf_new()) == NULL) 881 return SSH_ERR_ALLOC_FAIL; 882 r = to_blob_buf(key, tmp, force_plain, opts); 883 if (r == 0) 884 r = sshbuf_put_stringb(b, tmp); 885 sshbuf_free(tmp); 886 return r; 887 } 888 889 int 890 sshkey_puts(const struct sshkey *key, struct sshbuf *b) 891 { 892 return sshkey_puts_opts_internal(key, b, SSHKEY_SERIALIZE_DEFAULT, 0); 893 } 894 895 int 896 sshkey_putb_plain(const struct sshkey *key, struct sshbuf *b) 897 { 898 return to_blob_buf(key, b, 1, SSHKEY_SERIALIZE_DEFAULT); 899 } 900 901 int 902 sshkey_puts_plain(const struct sshkey *key, struct sshbuf *b) 903 { 904 return sshkey_puts_opts_internal(key, b, SSHKEY_SERIALIZE_DEFAULT, 1); 905 } 906 907 static int 908 to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp, int force_plain, 909 enum sshkey_serialize_rep opts) 910 { 911 int ret = SSH_ERR_INTERNAL_ERROR; 912 size_t len; 913 struct sshbuf *b = NULL; 914 915 if (lenp != NULL) 916 *lenp = 0; 917 if (blobp != NULL) 918 *blobp = NULL; 919 if ((b = sshbuf_new()) == NULL) 920 return SSH_ERR_ALLOC_FAIL; 921 if ((ret = to_blob_buf(key, b, force_plain, opts)) != 0) 922 goto out; 923 len = sshbuf_len(b); 924 if (lenp != NULL) 925 *lenp = len; 926 if (blobp != NULL) { 927 if ((*blobp = malloc(len)) == NULL) { 928 ret = SSH_ERR_ALLOC_FAIL; 929 goto out; 930 } 931 memcpy(*blobp, sshbuf_ptr(b), len); 932 } 933 ret = 0; 934 out: 935 sshbuf_free(b); 936 return ret; 937 } 938 939 int 940 sshkey_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp) 941 { 942 return to_blob(key, blobp, lenp, 0, SSHKEY_SERIALIZE_DEFAULT); 943 } 944 945 int 946 sshkey_plain_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp) 947 { 948 return to_blob(key, blobp, lenp, 1, SSHKEY_SERIALIZE_DEFAULT); 949 } 950 951 int 952 sshkey_fingerprint_raw(const struct sshkey *k, int dgst_alg, 953 u_char **retp, size_t *lenp) 954 { 955 u_char *blob = NULL, *ret = NULL; 956 size_t blob_len = 0; 957 int r = SSH_ERR_INTERNAL_ERROR; 958 959 if (retp != NULL) 960 *retp = NULL; 961 if (lenp != NULL) 962 *lenp = 0; 963 if (ssh_digest_bytes(dgst_alg) == 0) { 964 r = SSH_ERR_INVALID_ARGUMENT; 965 goto out; 966 } 967 if ((r = to_blob(k, &blob, &blob_len, 1, SSHKEY_SERIALIZE_DEFAULT)) 968 != 0) 969 goto out; 970 if ((ret = calloc(1, SSH_DIGEST_MAX_LENGTH)) == NULL) { 971 r = SSH_ERR_ALLOC_FAIL; 972 goto out; 973 } 974 if ((r = ssh_digest_memory(dgst_alg, blob, blob_len, 975 ret, SSH_DIGEST_MAX_LENGTH)) != 0) 976 goto out; 977 /* success */ 978 if (retp != NULL) { 979 *retp = ret; 980 ret = NULL; 981 } 982 if (lenp != NULL) 983 *lenp = ssh_digest_bytes(dgst_alg); 984 r = 0; 985 out: 986 free(ret); 987 if (blob != NULL) 988 freezero(blob, blob_len); 989 return r; 990 } 991 992 static char * 993 fingerprint_b64(const char *alg, u_char *dgst_raw, size_t dgst_raw_len) 994 { 995 char *ret; 996 size_t plen = strlen(alg) + 1; 997 size_t rlen = ((dgst_raw_len + 2) / 3) * 4 + plen + 1; 998 999 if (dgst_raw_len > 65536 || (ret = calloc(1, rlen)) == NULL) 1000 return NULL; 1001 strlcpy(ret, alg, rlen); 1002 strlcat(ret, ":", rlen); 1003 if (dgst_raw_len == 0) 1004 return ret; 1005 if (b64_ntop(dgst_raw, dgst_raw_len, ret + plen, rlen - plen) == -1) { 1006 freezero(ret, rlen); 1007 return NULL; 1008 } 1009 /* Trim padding characters from end */ 1010 ret[strcspn(ret, "=")] = '\0'; 1011 return ret; 1012 } 1013 1014 static char * 1015 fingerprint_hex(const char *alg, u_char *dgst_raw, size_t dgst_raw_len) 1016 { 1017 char *retval, hex[5]; 1018 size_t i, rlen = dgst_raw_len * 3 + strlen(alg) + 2; 1019 1020 if (dgst_raw_len > 65536 || (retval = calloc(1, rlen)) == NULL) 1021 return NULL; 1022 strlcpy(retval, alg, rlen); 1023 strlcat(retval, ":", rlen); 1024 for (i = 0; i < dgst_raw_len; i++) { 1025 snprintf(hex, sizeof(hex), "%s%02x", 1026 i > 0 ? ":" : "", dgst_raw[i]); 1027 strlcat(retval, hex, rlen); 1028 } 1029 return retval; 1030 } 1031 1032 static char * 1033 fingerprint_bubblebabble(u_char *dgst_raw, size_t dgst_raw_len) 1034 { 1035 char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' }; 1036 char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm', 1037 'n', 'p', 'r', 's', 't', 'v', 'z', 'x' }; 1038 u_int i, j = 0, rounds, seed = 1; 1039 char *retval; 1040 1041 rounds = (dgst_raw_len / 2) + 1; 1042 if ((retval = calloc(rounds, 6)) == NULL) 1043 return NULL; 1044 retval[j++] = 'x'; 1045 for (i = 0; i < rounds; i++) { 1046 u_int idx0, idx1, idx2, idx3, idx4; 1047 if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) { 1048 idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) + 1049 seed) % 6; 1050 idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15; 1051 idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) + 1052 (seed / 6)) % 6; 1053 retval[j++] = vowels[idx0]; 1054 retval[j++] = consonants[idx1]; 1055 retval[j++] = vowels[idx2]; 1056 if ((i + 1) < rounds) { 1057 idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15; 1058 idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15; 1059 retval[j++] = consonants[idx3]; 1060 retval[j++] = '-'; 1061 retval[j++] = consonants[idx4]; 1062 seed = ((seed * 5) + 1063 ((((u_int)(dgst_raw[2 * i])) * 7) + 1064 ((u_int)(dgst_raw[(2 * i) + 1])))) % 36; 1065 } 1066 } else { 1067 idx0 = seed % 6; 1068 idx1 = 16; 1069 idx2 = seed / 6; 1070 retval[j++] = vowels[idx0]; 1071 retval[j++] = consonants[idx1]; 1072 retval[j++] = vowels[idx2]; 1073 } 1074 } 1075 retval[j++] = 'x'; 1076 retval[j++] = '\0'; 1077 return retval; 1078 } 1079 1080 /* 1081 * Draw an ASCII-Art representing the fingerprint so human brain can 1082 * profit from its built-in pattern recognition ability. 1083 * This technique is called "random art" and can be found in some 1084 * scientific publications like this original paper: 1085 * 1086 * "Hash Visualization: a New Technique to improve Real-World Security", 1087 * Perrig A. and Song D., 1999, International Workshop on Cryptographic 1088 * Techniques and E-Commerce (CrypTEC '99) 1089 * sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf 1090 * 1091 * The subject came up in a talk by Dan Kaminsky, too. 1092 * 1093 * If you see the picture is different, the key is different. 1094 * If the picture looks the same, you still know nothing. 1095 * 1096 * The algorithm used here is a worm crawling over a discrete plane, 1097 * leaving a trace (augmenting the field) everywhere it goes. 1098 * Movement is taken from dgst_raw 2bit-wise. Bumping into walls 1099 * makes the respective movement vector be ignored for this turn. 1100 * Graphs are not unambiguous, because circles in graphs can be 1101 * walked in either direction. 1102 */ 1103 1104 /* 1105 * Field sizes for the random art. Have to be odd, so the starting point 1106 * can be in the exact middle of the picture, and FLDBASE should be >=8 . 1107 * Else pictures would be too dense, and drawing the frame would 1108 * fail, too, because the key type would not fit in anymore. 1109 */ 1110 #define FLDBASE 8 1111 #define FLDSIZE_Y (FLDBASE + 1) 1112 #define FLDSIZE_X (FLDBASE * 2 + 1) 1113 static char * 1114 fingerprint_randomart(const char *alg, u_char *dgst_raw, size_t dgst_raw_len, 1115 const struct sshkey *k) 1116 { 1117 /* 1118 * Chars to be used after each other every time the worm 1119 * intersects with itself. Matter of taste. 1120 */ 1121 const char *augmentation_string = " .o+=*BOX@%&#/^SE"; 1122 char *retval, *p, title[FLDSIZE_X], hash[FLDSIZE_X]; 1123 u_char field[FLDSIZE_X][FLDSIZE_Y]; 1124 size_t i, tlen, hlen; 1125 u_int b; 1126 int x, y, r; 1127 size_t len = strlen(augmentation_string) - 1; 1128 1129 if ((retval = calloc((FLDSIZE_X + 3), (FLDSIZE_Y + 2))) == NULL) 1130 return NULL; 1131 1132 /* initialize field */ 1133 memset(field, 0, FLDSIZE_X * FLDSIZE_Y * sizeof(char)); 1134 x = FLDSIZE_X / 2; 1135 y = FLDSIZE_Y / 2; 1136 1137 /* process raw key */ 1138 for (i = 0; i < dgst_raw_len; i++) { 1139 int input; 1140 /* each byte conveys four 2-bit move commands */ 1141 input = dgst_raw[i]; 1142 for (b = 0; b < 4; b++) { 1143 /* evaluate 2 bit, rest is shifted later */ 1144 x += (input & 0x1) ? 1 : -1; 1145 y += (input & 0x2) ? 1 : -1; 1146 1147 /* assure we are still in bounds */ 1148 x = MAXIMUM(x, 0); 1149 y = MAXIMUM(y, 0); 1150 x = MINIMUM(x, FLDSIZE_X - 1); 1151 y = MINIMUM(y, FLDSIZE_Y - 1); 1152 1153 /* augment the field */ 1154 if (field[x][y] < len - 2) 1155 field[x][y]++; 1156 input = input >> 2; 1157 } 1158 } 1159 1160 /* mark starting point and end point*/ 1161 field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = len - 1; 1162 field[x][y] = len; 1163 1164 /* assemble title */ 1165 r = snprintf(title, sizeof(title), "[%s %u]", 1166 sshkey_type(k), sshkey_size(k)); 1167 /* If [type size] won't fit, then try [type]; fits "[ED25519-CERT]" */ 1168 if (r < 0 || r > (int)sizeof(title)) 1169 r = snprintf(title, sizeof(title), "[%s]", sshkey_type(k)); 1170 tlen = (r <= 0) ? 0 : strlen(title); 1171 1172 /* assemble hash ID. */ 1173 r = snprintf(hash, sizeof(hash), "[%s]", alg); 1174 hlen = (r <= 0) ? 0 : strlen(hash); 1175 1176 /* output upper border */ 1177 p = retval; 1178 *p++ = '+'; 1179 for (i = 0; i < (FLDSIZE_X - tlen) / 2; i++) 1180 *p++ = '-'; 1181 memcpy(p, title, tlen); 1182 p += tlen; 1183 for (i += tlen; i < FLDSIZE_X; i++) 1184 *p++ = '-'; 1185 *p++ = '+'; 1186 *p++ = '\n'; 1187 1188 /* output content */ 1189 for (y = 0; y < FLDSIZE_Y; y++) { 1190 *p++ = '|'; 1191 for (x = 0; x < FLDSIZE_X; x++) 1192 *p++ = augmentation_string[MINIMUM(field[x][y], len)]; 1193 *p++ = '|'; 1194 *p++ = '\n'; 1195 } 1196 1197 /* output lower border */ 1198 *p++ = '+'; 1199 for (i = 0; i < (FLDSIZE_X - hlen) / 2; i++) 1200 *p++ = '-'; 1201 memcpy(p, hash, hlen); 1202 p += hlen; 1203 for (i += hlen; i < FLDSIZE_X; i++) 1204 *p++ = '-'; 1205 *p++ = '+'; 1206 1207 return retval; 1208 } 1209 1210 char * 1211 sshkey_fingerprint(const struct sshkey *k, int dgst_alg, 1212 enum sshkey_fp_rep dgst_rep) 1213 { 1214 char *retval = NULL; 1215 u_char *dgst_raw; 1216 size_t dgst_raw_len; 1217 1218 if (sshkey_fingerprint_raw(k, dgst_alg, &dgst_raw, &dgst_raw_len) != 0) 1219 return NULL; 1220 switch (dgst_rep) { 1221 case SSH_FP_DEFAULT: 1222 if (dgst_alg == SSH_DIGEST_MD5) { 1223 retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg), 1224 dgst_raw, dgst_raw_len); 1225 } else { 1226 retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg), 1227 dgst_raw, dgst_raw_len); 1228 } 1229 break; 1230 case SSH_FP_HEX: 1231 retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg), 1232 dgst_raw, dgst_raw_len); 1233 break; 1234 case SSH_FP_BASE64: 1235 retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg), 1236 dgst_raw, dgst_raw_len); 1237 break; 1238 case SSH_FP_BUBBLEBABBLE: 1239 retval = fingerprint_bubblebabble(dgst_raw, dgst_raw_len); 1240 break; 1241 case SSH_FP_RANDOMART: 1242 retval = fingerprint_randomart(ssh_digest_alg_name(dgst_alg), 1243 dgst_raw, dgst_raw_len, k); 1244 break; 1245 default: 1246 freezero(dgst_raw, dgst_raw_len); 1247 return NULL; 1248 } 1249 freezero(dgst_raw, dgst_raw_len); 1250 return retval; 1251 } 1252 1253 static int 1254 peek_type_nid(const char *s, size_t l, int *nid) 1255 { 1256 const struct sshkey_impl *impl; 1257 int i; 1258 1259 for (i = 0; keyimpls[i] != NULL; i++) { 1260 impl = keyimpls[i]; 1261 if (impl->name == NULL || strlen(impl->name) != l) 1262 continue; 1263 if (memcmp(s, impl->name, l) == 0) { 1264 *nid = -1; 1265 if (key_type_is_ecdsa_variant(impl->type)) 1266 *nid = impl->nid; 1267 return impl->type; 1268 } 1269 } 1270 return KEY_UNSPEC; 1271 } 1272 1273 /* XXX this can now be made const char * */ 1274 int 1275 sshkey_read(struct sshkey *ret, char **cpp) 1276 { 1277 struct sshkey *k; 1278 char *cp, *blobcopy; 1279 size_t space; 1280 int r, type, curve_nid = -1; 1281 struct sshbuf *blob; 1282 1283 if (ret == NULL) 1284 return SSH_ERR_INVALID_ARGUMENT; 1285 if (ret->type != KEY_UNSPEC && sshkey_impl_from_type(ret->type) == NULL) 1286 return SSH_ERR_INVALID_ARGUMENT; 1287 1288 /* Decode type */ 1289 cp = *cpp; 1290 space = strcspn(cp, " \t"); 1291 if (space == strlen(cp)) 1292 return SSH_ERR_INVALID_FORMAT; 1293 if ((type = peek_type_nid(cp, space, &curve_nid)) == KEY_UNSPEC) 1294 return SSH_ERR_INVALID_FORMAT; 1295 1296 /* skip whitespace */ 1297 for (cp += space; *cp == ' ' || *cp == '\t'; cp++) 1298 ; 1299 if (*cp == '\0') 1300 return SSH_ERR_INVALID_FORMAT; 1301 if (ret->type != KEY_UNSPEC && ret->type != type) 1302 return SSH_ERR_KEY_TYPE_MISMATCH; 1303 if ((blob = sshbuf_new()) == NULL) 1304 return SSH_ERR_ALLOC_FAIL; 1305 1306 /* find end of keyblob and decode */ 1307 space = strcspn(cp, " \t"); 1308 if ((blobcopy = strndup(cp, space)) == NULL) { 1309 sshbuf_free(blob); 1310 return SSH_ERR_ALLOC_FAIL; 1311 } 1312 if ((r = sshbuf_b64tod(blob, blobcopy)) != 0) { 1313 free(blobcopy); 1314 sshbuf_free(blob); 1315 return r; 1316 } 1317 free(blobcopy); 1318 if ((r = sshkey_fromb(blob, &k)) != 0) { 1319 sshbuf_free(blob); 1320 return r; 1321 } 1322 sshbuf_free(blob); 1323 1324 /* skip whitespace and leave cp at start of comment */ 1325 for (cp += space; *cp == ' ' || *cp == '\t'; cp++) 1326 ; 1327 1328 /* ensure type of blob matches type at start of line */ 1329 if (k->type != type) { 1330 sshkey_free(k); 1331 return SSH_ERR_KEY_TYPE_MISMATCH; 1332 } 1333 if (key_type_is_ecdsa_variant(type) && curve_nid != k->ecdsa_nid) { 1334 sshkey_free(k); 1335 return SSH_ERR_EC_CURVE_MISMATCH; 1336 } 1337 1338 /* Fill in ret from parsed key */ 1339 sshkey_free_contents(ret); 1340 *ret = *k; 1341 freezero(k, sizeof(*k)); 1342 1343 /* success */ 1344 *cpp = cp; 1345 return 0; 1346 } 1347 1348 int 1349 sshkey_to_base64(const struct sshkey *key, char **b64p) 1350 { 1351 int r = SSH_ERR_INTERNAL_ERROR; 1352 struct sshbuf *b = NULL; 1353 char *uu = NULL; 1354 1355 if (b64p != NULL) 1356 *b64p = NULL; 1357 if ((b = sshbuf_new()) == NULL) 1358 return SSH_ERR_ALLOC_FAIL; 1359 if ((r = sshkey_putb(key, b)) != 0) 1360 goto out; 1361 if ((uu = sshbuf_dtob64_string(b, 0)) == NULL) { 1362 r = SSH_ERR_ALLOC_FAIL; 1363 goto out; 1364 } 1365 /* Success */ 1366 if (b64p != NULL) { 1367 *b64p = uu; 1368 uu = NULL; 1369 } 1370 r = 0; 1371 out: 1372 sshbuf_free(b); 1373 free(uu); 1374 return r; 1375 } 1376 1377 int 1378 sshkey_format_text(const struct sshkey *key, struct sshbuf *b) 1379 { 1380 int r = SSH_ERR_INTERNAL_ERROR; 1381 char *uu = NULL; 1382 1383 if ((r = sshkey_to_base64(key, &uu)) != 0) 1384 goto out; 1385 if ((r = sshbuf_putf(b, "%s %s", 1386 sshkey_ssh_name(key), uu)) != 0) 1387 goto out; 1388 r = 0; 1389 out: 1390 free(uu); 1391 return r; 1392 } 1393 1394 int 1395 sshkey_write(const struct sshkey *key, FILE *f) 1396 { 1397 struct sshbuf *b = NULL; 1398 int r = SSH_ERR_INTERNAL_ERROR; 1399 1400 if ((b = sshbuf_new()) == NULL) 1401 return SSH_ERR_ALLOC_FAIL; 1402 if ((r = sshkey_format_text(key, b)) != 0) 1403 goto out; 1404 if (fwrite(sshbuf_ptr(b), sshbuf_len(b), 1, f) != 1) { 1405 if (feof(f)) 1406 errno = EPIPE; 1407 r = SSH_ERR_SYSTEM_ERROR; 1408 goto out; 1409 } 1410 /* Success */ 1411 r = 0; 1412 out: 1413 sshbuf_free(b); 1414 return r; 1415 } 1416 1417 const char * 1418 sshkey_cert_type(const struct sshkey *k) 1419 { 1420 switch (k->cert->type) { 1421 case SSH2_CERT_TYPE_USER: 1422 return "user"; 1423 case SSH2_CERT_TYPE_HOST: 1424 return "host"; 1425 default: 1426 return "unknown"; 1427 } 1428 } 1429 1430 int 1431 sshkey_check_rsa_length(const struct sshkey *k, int min_size) 1432 { 1433 #ifdef WITH_OPENSSL 1434 int nbits; 1435 1436 if (k == NULL || k->pkey == NULL || 1437 (k->type != KEY_RSA && k->type != KEY_RSA_CERT)) 1438 return 0; 1439 nbits = EVP_PKEY_bits(k->pkey); 1440 if (nbits < SSH_RSA_MINIMUM_MODULUS_SIZE || 1441 (min_size > 0 && nbits < min_size)) 1442 return SSH_ERR_KEY_LENGTH; 1443 #endif /* WITH_OPENSSL */ 1444 return 0; 1445 } 1446 1447 #ifdef WITH_OPENSSL 1448 int 1449 sshkey_ecdsa_key_to_nid(const EC_KEY *k) 1450 { 1451 const EC_GROUP *g; 1452 int nid; 1453 1454 if (k == NULL || (g = EC_KEY_get0_group(k)) == NULL) 1455 return -1; 1456 if ((nid = EC_GROUP_get_curve_name(g)) <= 0) 1457 return -1; 1458 return nid; 1459 } 1460 1461 int 1462 sshkey_ecdsa_pkey_to_nid(EVP_PKEY *pkey) 1463 { 1464 return sshkey_ecdsa_key_to_nid(EVP_PKEY_get0_EC_KEY(pkey)); 1465 } 1466 #endif /* WITH_OPENSSL */ 1467 1468 int 1469 sshkey_generate(int type, u_int bits, struct sshkey **keyp) 1470 { 1471 struct sshkey *k; 1472 int ret = SSH_ERR_INTERNAL_ERROR; 1473 const struct sshkey_impl *impl; 1474 1475 if (keyp == NULL || sshkey_type_is_cert(type)) 1476 return SSH_ERR_INVALID_ARGUMENT; 1477 *keyp = NULL; 1478 if ((impl = sshkey_impl_from_type(type)) == NULL) 1479 return SSH_ERR_KEY_TYPE_UNKNOWN; 1480 if (impl->funcs->generate == NULL) 1481 return SSH_ERR_FEATURE_UNSUPPORTED; 1482 if ((k = sshkey_new(KEY_UNSPEC)) == NULL) 1483 return SSH_ERR_ALLOC_FAIL; 1484 k->type = type; 1485 if ((ret = impl->funcs->generate(k, bits)) != 0) { 1486 sshkey_free(k); 1487 return ret; 1488 } 1489 /* success */ 1490 *keyp = k; 1491 return 0; 1492 } 1493 1494 int 1495 sshkey_cert_copy(const struct sshkey *from_key, struct sshkey *to_key) 1496 { 1497 u_int i; 1498 const struct sshkey_cert *from; 1499 struct sshkey_cert *to; 1500 int r = SSH_ERR_INTERNAL_ERROR; 1501 1502 if (to_key == NULL || (from = from_key->cert) == NULL) 1503 return SSH_ERR_INVALID_ARGUMENT; 1504 1505 if ((to = cert_new()) == NULL) 1506 return SSH_ERR_ALLOC_FAIL; 1507 1508 if ((r = sshbuf_putb(to->certblob, from->certblob)) != 0 || 1509 (r = sshbuf_putb(to->critical, from->critical)) != 0 || 1510 (r = sshbuf_putb(to->extensions, from->extensions)) != 0) 1511 goto out; 1512 1513 to->serial = from->serial; 1514 to->type = from->type; 1515 if (from->key_id == NULL) 1516 to->key_id = NULL; 1517 else if ((to->key_id = strdup(from->key_id)) == NULL) { 1518 r = SSH_ERR_ALLOC_FAIL; 1519 goto out; 1520 } 1521 to->valid_after = from->valid_after; 1522 to->valid_before = from->valid_before; 1523 if (from->signature_key == NULL) 1524 to->signature_key = NULL; 1525 else if ((r = sshkey_from_private(from->signature_key, 1526 &to->signature_key)) != 0) 1527 goto out; 1528 if (from->signature_type != NULL && 1529 (to->signature_type = strdup(from->signature_type)) == NULL) { 1530 r = SSH_ERR_ALLOC_FAIL; 1531 goto out; 1532 } 1533 if (from->nprincipals > SSHKEY_CERT_MAX_PRINCIPALS) { 1534 r = SSH_ERR_INVALID_ARGUMENT; 1535 goto out; 1536 } 1537 if (from->nprincipals > 0) { 1538 if ((to->principals = calloc(from->nprincipals, 1539 sizeof(*to->principals))) == NULL) { 1540 r = SSH_ERR_ALLOC_FAIL; 1541 goto out; 1542 } 1543 for (i = 0; i < from->nprincipals; i++) { 1544 to->principals[i] = strdup(from->principals[i]); 1545 if (to->principals[i] == NULL) { 1546 to->nprincipals = i; 1547 r = SSH_ERR_ALLOC_FAIL; 1548 goto out; 1549 } 1550 } 1551 } 1552 to->nprincipals = from->nprincipals; 1553 1554 /* success */ 1555 cert_free(to_key->cert); 1556 to_key->cert = to; 1557 to = NULL; 1558 r = 0; 1559 out: 1560 cert_free(to); 1561 return r; 1562 } 1563 1564 int 1565 sshkey_copy_public_sk(const struct sshkey *from, struct sshkey *to) 1566 { 1567 /* Append security-key application string */ 1568 if ((to->sk_application = strdup(from->sk_application)) == NULL) 1569 return SSH_ERR_ALLOC_FAIL; 1570 return 0; 1571 } 1572 1573 int 1574 sshkey_from_private(const struct sshkey *k, struct sshkey **pkp) 1575 { 1576 struct sshkey *n = NULL; 1577 int r = SSH_ERR_INTERNAL_ERROR; 1578 const struct sshkey_impl *impl; 1579 1580 *pkp = NULL; 1581 if ((impl = sshkey_impl_from_key(k)) == NULL) 1582 return SSH_ERR_KEY_TYPE_UNKNOWN; 1583 if ((n = sshkey_new(k->type)) == NULL) { 1584 r = SSH_ERR_ALLOC_FAIL; 1585 goto out; 1586 } 1587 if ((r = impl->funcs->copy_public(k, n)) != 0) 1588 goto out; 1589 if (sshkey_is_cert(k) && (r = sshkey_cert_copy(k, n)) != 0) 1590 goto out; 1591 /* success */ 1592 *pkp = n; 1593 n = NULL; 1594 r = 0; 1595 out: 1596 sshkey_free(n); 1597 return r; 1598 } 1599 1600 int 1601 sshkey_is_shielded(struct sshkey *k) 1602 { 1603 return k != NULL && k->shielded_private != NULL; 1604 } 1605 1606 int 1607 sshkey_shield_private(struct sshkey *k) 1608 { 1609 struct sshbuf *prvbuf = NULL; 1610 u_char *prekey = NULL, *enc = NULL, keyiv[SSH_DIGEST_MAX_LENGTH]; 1611 struct sshcipher_ctx *cctx = NULL; 1612 const struct sshcipher *cipher; 1613 size_t i, enclen = 0; 1614 struct sshkey *kswap = NULL, tmp; 1615 int r = SSH_ERR_INTERNAL_ERROR; 1616 1617 #ifdef DEBUG_PK 1618 fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k)); 1619 #endif 1620 if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) { 1621 r = SSH_ERR_INVALID_ARGUMENT; 1622 goto out; 1623 } 1624 if (cipher_keylen(cipher) + cipher_ivlen(cipher) > 1625 ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) { 1626 r = SSH_ERR_INTERNAL_ERROR; 1627 goto out; 1628 } 1629 1630 /* Prepare a random pre-key, and from it an ephemeral key */ 1631 if ((r = sshkey_prekey_alloc(&prekey, SSHKEY_SHIELD_PREKEY_LEN)) != 0) 1632 goto out; 1633 arc4random_buf(prekey, SSHKEY_SHIELD_PREKEY_LEN); 1634 if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH, 1635 prekey, SSHKEY_SHIELD_PREKEY_LEN, 1636 keyiv, SSH_DIGEST_MAX_LENGTH)) != 0) 1637 goto out; 1638 #ifdef DEBUG_PK 1639 fprintf(stderr, "%s: key+iv\n", __func__); 1640 sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH), 1641 stderr); 1642 #endif 1643 if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher), 1644 keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 1)) != 0) 1645 goto out; 1646 1647 /* Serialise and encrypt the private key using the ephemeral key */ 1648 if ((prvbuf = sshbuf_new()) == NULL) { 1649 r = SSH_ERR_ALLOC_FAIL; 1650 goto out; 1651 } 1652 if (sshkey_is_shielded(k) && (r = sshkey_unshield_private(k)) != 0) 1653 goto out; 1654 if ((r = sshkey_private_serialize(k, prvbuf)) != 0) 1655 goto out; 1656 /* pad to cipher blocksize */ 1657 i = 0; 1658 while (sshbuf_len(prvbuf) % cipher_blocksize(cipher)) { 1659 if ((r = sshbuf_put_u8(prvbuf, ++i & 0xff)) != 0) 1660 goto out; 1661 } 1662 #ifdef DEBUG_PK 1663 fprintf(stderr, "%s: serialised\n", __func__); 1664 sshbuf_dump(prvbuf, stderr); 1665 #endif 1666 /* encrypt */ 1667 enclen = sshbuf_len(prvbuf); 1668 if ((enc = malloc(enclen)) == NULL) { 1669 r = SSH_ERR_ALLOC_FAIL; 1670 goto out; 1671 } 1672 if ((r = cipher_crypt(cctx, 0, enc, 1673 sshbuf_ptr(prvbuf), sshbuf_len(prvbuf), 0, 0)) != 0) 1674 goto out; 1675 #ifdef DEBUG_PK 1676 fprintf(stderr, "%s: encrypted\n", __func__); 1677 sshbuf_dump_data(enc, enclen, stderr); 1678 #endif 1679 1680 /* Make a scrubbed, public-only copy of our private key argument */ 1681 if ((r = sshkey_from_private(k, &kswap)) != 0) 1682 goto out; 1683 1684 /* Swap the private key out (it will be destroyed below) */ 1685 tmp = *kswap; 1686 *kswap = *k; 1687 *k = tmp; 1688 1689 /* Insert the shielded key into our argument */ 1690 k->shielded_private = enc; 1691 k->shielded_len = enclen; 1692 k->shield_prekey = prekey; 1693 k->shield_prekey_len = SSHKEY_SHIELD_PREKEY_LEN; 1694 enc = prekey = NULL; /* transferred */ 1695 enclen = 0; 1696 1697 /* preserve key fields that are required for correct operation */ 1698 k->sk_flags = kswap->sk_flags; 1699 1700 /* success */ 1701 r = 0; 1702 1703 out: 1704 /* XXX behaviour on error - invalidate original private key? */ 1705 cipher_free(cctx); 1706 explicit_bzero(keyiv, sizeof(keyiv)); 1707 explicit_bzero(&tmp, sizeof(tmp)); 1708 freezero(enc, enclen); 1709 sshkey_prekey_free(prekey, SSHKEY_SHIELD_PREKEY_LEN); 1710 sshkey_free(kswap); 1711 sshbuf_free(prvbuf); 1712 return r; 1713 } 1714 1715 /* Check deterministic padding after private key */ 1716 static int 1717 private2_check_padding(struct sshbuf *decrypted) 1718 { 1719 u_char pad; 1720 size_t i; 1721 int r; 1722 1723 i = 0; 1724 while (sshbuf_len(decrypted)) { 1725 if ((r = sshbuf_get_u8(decrypted, &pad)) != 0) 1726 goto out; 1727 if (pad != (++i & 0xff)) { 1728 r = SSH_ERR_INVALID_FORMAT; 1729 goto out; 1730 } 1731 } 1732 /* success */ 1733 r = 0; 1734 out: 1735 explicit_bzero(&pad, sizeof(pad)); 1736 explicit_bzero(&i, sizeof(i)); 1737 return r; 1738 } 1739 1740 int 1741 sshkey_unshield_private(struct sshkey *k) 1742 { 1743 struct sshbuf *prvbuf = NULL; 1744 u_char *cp, keyiv[SSH_DIGEST_MAX_LENGTH]; 1745 struct sshcipher_ctx *cctx = NULL; 1746 const struct sshcipher *cipher; 1747 struct sshkey *kswap = NULL, tmp; 1748 int r = SSH_ERR_INTERNAL_ERROR; 1749 1750 #ifdef DEBUG_PK 1751 fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k)); 1752 #endif 1753 if (!sshkey_is_shielded(k)) 1754 return 0; /* nothing to do */ 1755 1756 if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) { 1757 r = SSH_ERR_INVALID_ARGUMENT; 1758 goto out; 1759 } 1760 if (cipher_keylen(cipher) + cipher_ivlen(cipher) > 1761 ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) { 1762 r = SSH_ERR_INTERNAL_ERROR; 1763 goto out; 1764 } 1765 /* check size of shielded key blob */ 1766 if (k->shielded_len < cipher_blocksize(cipher) || 1767 (k->shielded_len % cipher_blocksize(cipher)) != 0) { 1768 r = SSH_ERR_INVALID_FORMAT; 1769 goto out; 1770 } 1771 1772 /* Calculate the ephemeral key from the prekey */ 1773 if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH, 1774 k->shield_prekey, k->shield_prekey_len, 1775 keyiv, SSH_DIGEST_MAX_LENGTH)) != 0) 1776 goto out; 1777 if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher), 1778 keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 0)) != 0) 1779 goto out; 1780 #ifdef DEBUG_PK 1781 fprintf(stderr, "%s: key+iv\n", __func__); 1782 sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH), 1783 stderr); 1784 #endif 1785 1786 /* Decrypt and parse the shielded private key using the ephemeral key */ 1787 if ((prvbuf = sshbuf_new()) == NULL) { 1788 r = SSH_ERR_ALLOC_FAIL; 1789 goto out; 1790 } 1791 if ((r = sshbuf_reserve(prvbuf, k->shielded_len, &cp)) != 0) 1792 goto out; 1793 /* decrypt */ 1794 #ifdef DEBUG_PK 1795 fprintf(stderr, "%s: encrypted\n", __func__); 1796 sshbuf_dump_data(k->shielded_private, k->shielded_len, stderr); 1797 #endif 1798 if ((r = cipher_crypt(cctx, 0, cp, 1799 k->shielded_private, k->shielded_len, 0, 0)) != 0) 1800 goto out; 1801 #ifdef DEBUG_PK 1802 fprintf(stderr, "%s: serialised\n", __func__); 1803 sshbuf_dump(prvbuf, stderr); 1804 #endif 1805 /* Parse private key */ 1806 if ((r = sshkey_private_deserialize(prvbuf, &kswap)) != 0) 1807 goto out; 1808 1809 if ((r = private2_check_padding(prvbuf)) != 0) 1810 goto out; 1811 1812 /* Swap the parsed key back into place */ 1813 tmp = *kswap; 1814 *kswap = *k; 1815 *k = tmp; 1816 1817 /* success */ 1818 r = 0; 1819 1820 out: 1821 cipher_free(cctx); 1822 explicit_bzero(keyiv, sizeof(keyiv)); 1823 explicit_bzero(&tmp, sizeof(tmp)); 1824 sshkey_free(kswap); 1825 sshbuf_free(prvbuf); 1826 return r; 1827 } 1828 1829 static int 1830 cert_parse(struct sshbuf *b, struct sshkey *key, struct sshbuf *certbuf, 1831 const char *ca_sigalg_allowlist) 1832 { 1833 struct sshbuf *principals = NULL, *crit = NULL; 1834 struct sshbuf *exts = NULL, *ca = NULL; 1835 u_char *sig = NULL; 1836 char *sigtype = NULL; 1837 size_t signed_len = 0, slen = 0, kidlen = 0; 1838 int ret = SSH_ERR_INTERNAL_ERROR; 1839 1840 /* Copy the entire key blob for verification and later serialisation */ 1841 if ((ret = sshbuf_putb(key->cert->certblob, certbuf)) != 0) 1842 return ret; 1843 1844 /* Parse body of certificate up to signature */ 1845 if ((ret = sshbuf_get_u64(b, &key->cert->serial)) != 0 || 1846 (ret = sshbuf_get_u32(b, &key->cert->type)) != 0 || 1847 (ret = sshbuf_get_cstring(b, &key->cert->key_id, &kidlen)) != 0 || 1848 (ret = sshbuf_froms(b, &principals)) != 0 || 1849 (ret = sshbuf_get_u64(b, &key->cert->valid_after)) != 0 || 1850 (ret = sshbuf_get_u64(b, &key->cert->valid_before)) != 0 || 1851 (ret = sshbuf_froms(b, &crit)) != 0 || 1852 (ret = sshbuf_froms(b, &exts)) != 0 || 1853 (ret = sshbuf_get_string_direct(b, NULL, NULL)) != 0 || 1854 (ret = sshbuf_froms(b, &ca)) != 0) { 1855 /* XXX debug print error for ret */ 1856 ret = SSH_ERR_INVALID_FORMAT; 1857 goto out; 1858 } 1859 1860 /* Signature is left in the buffer so we can calculate this length */ 1861 signed_len = sshbuf_len(key->cert->certblob) - sshbuf_len(b); 1862 1863 if ((ret = sshbuf_get_string(b, &sig, &slen)) != 0) { 1864 ret = SSH_ERR_INVALID_FORMAT; 1865 goto out; 1866 } 1867 1868 /* Is this a signature we're prepared to accept? */ 1869 if ((ret = sshkey_get_sigtype(sig, slen, &sigtype)) != 0) { 1870 ret = SSH_ERR_INVALID_FORMAT; 1871 goto out; 1872 } 1873 if (ca_sigalg_allowlist != NULL && 1874 match_pattern_list(sigtype, ca_sigalg_allowlist, 0) != 1) { 1875 ret = SSH_ERR_SIGN_ALG_UNSUPPORTED; 1876 goto out; 1877 } 1878 1879 /* Parse CA key and check whether we might accept it */ 1880 if (sshkey_from_blob_internal(ca, &key->cert->signature_key, 0, 1881 ca_sigalg_allowlist, NULL) != 0) { 1882 ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 1883 goto out; 1884 } 1885 if (!sshkey_type_is_valid_ca(key->cert->signature_key->type)) { 1886 ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 1887 goto out; 1888 } 1889 1890 if (key->cert->type != SSH2_CERT_TYPE_USER && 1891 key->cert->type != SSH2_CERT_TYPE_HOST) { 1892 ret = SSH_ERR_KEY_CERT_UNKNOWN_TYPE; 1893 goto out; 1894 } 1895 1896 /* Parse principals section */ 1897 while (sshbuf_len(principals) > 0) { 1898 char *principal = NULL; 1899 char **oprincipals = NULL; 1900 1901 if (key->cert->nprincipals >= SSHKEY_CERT_MAX_PRINCIPALS) { 1902 ret = SSH_ERR_INVALID_FORMAT; 1903 goto out; 1904 } 1905 if ((ret = sshbuf_get_cstring(principals, &principal, 1906 NULL)) != 0) { 1907 ret = SSH_ERR_INVALID_FORMAT; 1908 goto out; 1909 } 1910 oprincipals = key->cert->principals; 1911 key->cert->principals = recallocarray(key->cert->principals, 1912 key->cert->nprincipals, key->cert->nprincipals + 1, 1913 sizeof(*key->cert->principals)); 1914 if (key->cert->principals == NULL) { 1915 free(principal); 1916 key->cert->principals = oprincipals; 1917 ret = SSH_ERR_ALLOC_FAIL; 1918 goto out; 1919 } 1920 key->cert->principals[key->cert->nprincipals++] = principal; 1921 } 1922 1923 /* 1924 * Stash a copies of the critical options and extensions sections 1925 * for later use. 1926 */ 1927 if ((ret = sshbuf_putb(key->cert->critical, crit)) != 0 || 1928 (exts != NULL && 1929 (ret = sshbuf_putb(key->cert->extensions, exts)) != 0)) 1930 goto out; 1931 1932 /* 1933 * Validate critical options and extensions sections format. 1934 */ 1935 while (sshbuf_len(crit) != 0) { 1936 if ((ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0 || 1937 (ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0) { 1938 sshbuf_reset(key->cert->critical); 1939 ret = SSH_ERR_INVALID_FORMAT; 1940 goto out; 1941 } 1942 } 1943 while (exts != NULL && sshbuf_len(exts) != 0) { 1944 if ((ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0 || 1945 (ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0) { 1946 sshbuf_reset(key->cert->extensions); 1947 ret = SSH_ERR_INVALID_FORMAT; 1948 goto out; 1949 } 1950 } 1951 1952 /* Finally, validate signature */ 1953 if ((ret = sshkey_verify(key->cert->signature_key, sig, slen, 1954 sshbuf_ptr(key->cert->certblob), signed_len, NULL, 0, NULL)) != 0) 1955 goto out; 1956 1957 /* Success */ 1958 ret = 0; 1959 key->cert->signature_type = sigtype; 1960 sigtype = NULL; 1961 out: 1962 sshbuf_free(ca); 1963 sshbuf_free(crit); 1964 sshbuf_free(exts); 1965 sshbuf_free(principals); 1966 free(sig); 1967 free(sigtype); 1968 return ret; 1969 } 1970 1971 int 1972 sshkey_deserialize_sk(struct sshbuf *b, struct sshkey *key) 1973 { 1974 /* Parse additional security-key application string */ 1975 if (sshbuf_get_cstring(b, &key->sk_application, NULL) != 0) 1976 return SSH_ERR_INVALID_FORMAT; 1977 return 0; 1978 } 1979 1980 static int 1981 sshkey_from_blob_internal(struct sshbuf *b, struct sshkey **keyp, 1982 int allow_cert, const char *alg_allowlist, const char *ca_sigalg_allowlist) 1983 { 1984 int type, ret = SSH_ERR_INTERNAL_ERROR; 1985 char *ktype = NULL; 1986 struct sshkey *key = NULL; 1987 struct sshbuf *copy; 1988 const struct sshkey_impl *impl; 1989 1990 #ifdef DEBUG_PK /* XXX */ 1991 sshbuf_dump(b, stderr); 1992 #endif 1993 if (keyp != NULL) 1994 *keyp = NULL; 1995 if ((copy = sshbuf_fromb(b)) == NULL) { 1996 ret = SSH_ERR_ALLOC_FAIL; 1997 goto out; 1998 } 1999 if (sshbuf_get_cstring(b, &ktype, NULL) != 0) { 2000 ret = SSH_ERR_INVALID_FORMAT; 2001 goto out; 2002 } 2003 2004 type = sshkey_type_from_name(ktype); 2005 if (!allow_cert && sshkey_type_is_cert(type)) { 2006 ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 2007 goto out; 2008 } 2009 2010 if (alg_allowlist != NULL && 2011 !sshkey_match_keyname_to_sigalgs(ktype, alg_allowlist)) { 2012 ret = SSH_ERR_KEY_ALG_UNSUPPORTED; 2013 goto out; 2014 } 2015 2016 if ((impl = sshkey_impl_from_type(type)) == NULL) { 2017 ret = SSH_ERR_KEY_TYPE_UNKNOWN; 2018 goto out; 2019 } 2020 if ((key = sshkey_new(type)) == NULL) { 2021 ret = SSH_ERR_ALLOC_FAIL; 2022 goto out; 2023 } 2024 if (sshkey_type_is_cert(type)) { 2025 /* Skip nonce that precedes all certificates */ 2026 if (sshbuf_get_string_direct(b, NULL, NULL) != 0) { 2027 ret = SSH_ERR_INVALID_FORMAT; 2028 goto out; 2029 } 2030 } 2031 if ((ret = impl->funcs->deserialize_public(ktype, b, key)) != 0) 2032 goto out; 2033 2034 /* Parse certificate potion */ 2035 if (sshkey_is_cert(key) && 2036 (ret = cert_parse(b, key, copy, ca_sigalg_allowlist)) != 0) 2037 goto out; 2038 2039 if (key != NULL && sshbuf_len(b) != 0) { 2040 ret = SSH_ERR_INVALID_FORMAT; 2041 goto out; 2042 } 2043 ret = 0; 2044 if (keyp != NULL) { 2045 *keyp = key; 2046 key = NULL; 2047 } 2048 out: 2049 sshbuf_free(copy); 2050 sshkey_free(key); 2051 free(ktype); 2052 return ret; 2053 } 2054 2055 int 2056 sshkey_from_blob(const u_char *blob, size_t blen, struct sshkey **keyp) 2057 { 2058 struct sshbuf *b; 2059 int r; 2060 2061 if ((b = sshbuf_from(blob, blen)) == NULL) 2062 return SSH_ERR_ALLOC_FAIL; 2063 r = sshkey_from_blob_internal(b, keyp, 1, NULL, NULL); 2064 sshbuf_free(b); 2065 return r; 2066 } 2067 2068 int 2069 sshkey_fromb(struct sshbuf *b, struct sshkey **keyp) 2070 { 2071 return sshkey_from_blob_internal(b, keyp, 1, NULL, NULL); 2072 } 2073 2074 int 2075 sshkey_fromb_allowlist(struct sshbuf *b, struct sshkey **keyp, 2076 const char *alg_allowlist, const char *ca_sigalg_allowlist) 2077 { 2078 return sshkey_from_blob_internal(b, keyp, 1, 2079 alg_allowlist, ca_sigalg_allowlist); 2080 } 2081 2082 int 2083 sshkey_froms(struct sshbuf *buf, struct sshkey **keyp) 2084 { 2085 struct sshbuf *b; 2086 int r; 2087 2088 if ((r = sshbuf_froms(buf, &b)) != 0) 2089 return r; 2090 r = sshkey_from_blob_internal(b, keyp, 1, NULL, NULL); 2091 sshbuf_free(b); 2092 return r; 2093 } 2094 2095 int 2096 sshkey_get_sigtype(const u_char *sig, size_t siglen, char **sigtypep) 2097 { 2098 int r; 2099 struct sshbuf *b = NULL; 2100 char *sigtype = NULL; 2101 2102 if (sigtypep != NULL) 2103 *sigtypep = NULL; 2104 if ((b = sshbuf_from(sig, siglen)) == NULL) 2105 return SSH_ERR_ALLOC_FAIL; 2106 if ((r = sshbuf_get_cstring(b, &sigtype, NULL)) != 0) 2107 goto out; 2108 /* success */ 2109 if (sigtypep != NULL) { 2110 *sigtypep = sigtype; 2111 sigtype = NULL; 2112 } 2113 r = 0; 2114 out: 2115 free(sigtype); 2116 sshbuf_free(b); 2117 return r; 2118 } 2119 2120 /* 2121 * 2122 * Checks whether a certificate's signature type is allowed. 2123 * Returns 0 (success) if the certificate signature type appears in the 2124 * "allowed" pattern-list, or the key is not a certificate to begin with. 2125 * Otherwise returns a ssherr.h code. 2126 */ 2127 int 2128 sshkey_check_cert_sigtype(const struct sshkey *key, const char *allowed) 2129 { 2130 if (key == NULL || allowed == NULL) 2131 return SSH_ERR_INVALID_ARGUMENT; 2132 if (!sshkey_type_is_cert(key->type)) 2133 return 0; 2134 if (key->cert == NULL || key->cert->signature_type == NULL) 2135 return SSH_ERR_INVALID_ARGUMENT; 2136 if (match_pattern_list(key->cert->signature_type, allowed, 0) != 1) 2137 return SSH_ERR_SIGN_ALG_UNSUPPORTED; 2138 return 0; 2139 } 2140 2141 /* 2142 * Returns the expected signature algorithm for a given public key algorithm. 2143 */ 2144 const char * 2145 sshkey_sigalg_by_name(const char *name) 2146 { 2147 const struct sshkey_impl *impl; 2148 int i; 2149 2150 for (i = 0; keyimpls[i] != NULL; i++) { 2151 impl = keyimpls[i]; 2152 if (strcmp(impl->name, name) != 0) 2153 continue; 2154 if (impl->sigalg != NULL) 2155 return impl->sigalg; 2156 if (!impl->cert) 2157 return impl->name; 2158 return sshkey_ssh_name_from_type_nid( 2159 sshkey_type_plain(impl->type), impl->nid); 2160 } 2161 return NULL; 2162 } 2163 2164 /* 2165 * Verifies that the signature algorithm appearing inside the signature blob 2166 * matches that which was requested. 2167 */ 2168 int 2169 sshkey_check_sigtype(const u_char *sig, size_t siglen, 2170 const char *requested_alg) 2171 { 2172 const char *expected_alg; 2173 char *sigtype = NULL; 2174 int r; 2175 2176 if (requested_alg == NULL) 2177 return 0; 2178 if ((expected_alg = sshkey_sigalg_by_name(requested_alg)) == NULL) 2179 return SSH_ERR_INVALID_ARGUMENT; 2180 if ((r = sshkey_get_sigtype(sig, siglen, &sigtype)) != 0) 2181 return r; 2182 r = strcmp(expected_alg, sigtype) == 0; 2183 free(sigtype); 2184 return r ? 0 : SSH_ERR_SIGN_ALG_UNSUPPORTED; 2185 } 2186 2187 int 2188 sshkey_sign(struct sshkey *key, 2189 u_char **sigp, size_t *lenp, 2190 const u_char *data, size_t datalen, 2191 const char *alg, const char *sk_provider, const char *sk_pin, u_int compat) 2192 { 2193 int was_shielded = sshkey_is_shielded(key); 2194 int r2, r = SSH_ERR_INTERNAL_ERROR; 2195 const struct sshkey_impl *impl; 2196 2197 if (sigp != NULL) 2198 *sigp = NULL; 2199 if (lenp != NULL) 2200 *lenp = 0; 2201 if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE) 2202 return SSH_ERR_INVALID_ARGUMENT; 2203 if ((impl = sshkey_impl_from_key(key)) == NULL) 2204 return SSH_ERR_KEY_TYPE_UNKNOWN; 2205 if ((r = sshkey_unshield_private(key)) != 0) 2206 return r; 2207 if (sshkey_is_sk(key)) { 2208 r = sshsk_sign(sk_provider, key, sigp, lenp, data, 2209 datalen, compat, sk_pin); 2210 } else if ((key->flags & SSHKEY_FLAG_EXT) != 0) { 2211 r = pkcs11_sign(key, sigp, lenp, data, datalen, 2212 alg, sk_provider, sk_pin, compat); 2213 } else { 2214 if (impl->funcs->sign == NULL) 2215 r = SSH_ERR_SIGN_ALG_UNSUPPORTED; 2216 else { 2217 r = impl->funcs->sign(key, sigp, lenp, data, datalen, 2218 alg, sk_provider, sk_pin, compat); 2219 } 2220 } 2221 if (was_shielded && (r2 = sshkey_shield_private(key)) != 0) 2222 return r2; 2223 return r; 2224 } 2225 2226 /* 2227 * ssh_key_verify returns 0 for a correct signature and < 0 on error. 2228 * If "alg" specified, then the signature must use that algorithm. 2229 */ 2230 int 2231 sshkey_verify(const struct sshkey *key, 2232 const u_char *sig, size_t siglen, 2233 const u_char *data, size_t dlen, const char *alg, u_int compat, 2234 struct sshkey_sig_details **detailsp) 2235 { 2236 const struct sshkey_impl *impl; 2237 2238 if (detailsp != NULL) 2239 *detailsp = NULL; 2240 if (siglen == 0 || dlen > SSH_KEY_MAX_SIGN_DATA_SIZE) 2241 return SSH_ERR_INVALID_ARGUMENT; 2242 if ((impl = sshkey_impl_from_key(key)) == NULL) 2243 return SSH_ERR_KEY_TYPE_UNKNOWN; 2244 return impl->funcs->verify(key, sig, siglen, data, dlen, 2245 alg, compat, detailsp); 2246 } 2247 2248 /* Convert a plain key to their _CERT equivalent */ 2249 int 2250 sshkey_to_certified(struct sshkey *k) 2251 { 2252 int newtype; 2253 2254 if ((newtype = sshkey_type_certified(k->type)) == -1) 2255 return SSH_ERR_INVALID_ARGUMENT; 2256 if ((k->cert = cert_new()) == NULL) 2257 return SSH_ERR_ALLOC_FAIL; 2258 k->type = newtype; 2259 return 0; 2260 } 2261 2262 /* Convert a certificate to its raw key equivalent */ 2263 int 2264 sshkey_drop_cert(struct sshkey *k) 2265 { 2266 if (!sshkey_type_is_cert(k->type)) 2267 return SSH_ERR_KEY_TYPE_UNKNOWN; 2268 cert_free(k->cert); 2269 k->cert = NULL; 2270 k->type = sshkey_type_plain(k->type); 2271 return 0; 2272 } 2273 2274 /* Sign a certified key, (re-)generating the signed certblob. */ 2275 int 2276 sshkey_certify_custom(struct sshkey *k, struct sshkey *ca, const char *alg, 2277 const char *sk_provider, const char *sk_pin, 2278 sshkey_certify_signer *signer, void *signer_ctx) 2279 { 2280 const struct sshkey_impl *impl; 2281 struct sshbuf *principals = NULL; 2282 u_char *ca_blob = NULL, *sig_blob = NULL, nonce[32]; 2283 size_t i, ca_len, sig_len; 2284 int ret = SSH_ERR_INTERNAL_ERROR; 2285 struct sshbuf *cert = NULL; 2286 char *sigtype = NULL; 2287 2288 if (k == NULL || k->cert == NULL || 2289 k->cert->certblob == NULL || ca == NULL) 2290 return SSH_ERR_INVALID_ARGUMENT; 2291 if (!sshkey_is_cert(k)) 2292 return SSH_ERR_KEY_TYPE_UNKNOWN; 2293 if (!sshkey_type_is_valid_ca(ca->type)) 2294 return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 2295 if ((impl = sshkey_impl_from_key(k)) == NULL) 2296 return SSH_ERR_INTERNAL_ERROR; 2297 2298 /* 2299 * If no alg specified as argument but a signature_type was set, 2300 * then prefer that. If both were specified, then they must match. 2301 */ 2302 if (alg == NULL) 2303 alg = k->cert->signature_type; 2304 else if (k->cert->signature_type != NULL && 2305 strcmp(alg, k->cert->signature_type) != 0) 2306 return SSH_ERR_INVALID_ARGUMENT; 2307 2308 /* 2309 * If no signing algorithm or signature_type was specified and we're 2310 * using a RSA key, then default to a good signature algorithm. 2311 */ 2312 if (alg == NULL && ca->type == KEY_RSA) 2313 alg = "rsa-sha2-512"; 2314 2315 if ((ret = sshkey_to_blob(ca, &ca_blob, &ca_len)) != 0) 2316 return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY; 2317 2318 cert = k->cert->certblob; /* for readability */ 2319 sshbuf_reset(cert); 2320 if ((ret = sshbuf_put_cstring(cert, sshkey_ssh_name(k))) != 0) 2321 goto out; 2322 2323 /* -v01 certs put nonce first */ 2324 arc4random_buf(&nonce, sizeof(nonce)); 2325 if ((ret = sshbuf_put_string(cert, nonce, sizeof(nonce))) != 0) 2326 goto out; 2327 2328 /* Public key next */ 2329 if ((ret = impl->funcs->serialize_public(k, cert, 2330 SSHKEY_SERIALIZE_DEFAULT)) != 0) 2331 goto out; 2332 2333 /* Then remaining cert fields */ 2334 if ((ret = sshbuf_put_u64(cert, k->cert->serial)) != 0 || 2335 (ret = sshbuf_put_u32(cert, k->cert->type)) != 0 || 2336 (ret = sshbuf_put_cstring(cert, k->cert->key_id)) != 0) 2337 goto out; 2338 2339 if ((principals = sshbuf_new()) == NULL) { 2340 ret = SSH_ERR_ALLOC_FAIL; 2341 goto out; 2342 } 2343 for (i = 0; i < k->cert->nprincipals; i++) { 2344 if ((ret = sshbuf_put_cstring(principals, 2345 k->cert->principals[i])) != 0) 2346 goto out; 2347 } 2348 if ((ret = sshbuf_put_stringb(cert, principals)) != 0 || 2349 (ret = sshbuf_put_u64(cert, k->cert->valid_after)) != 0 || 2350 (ret = sshbuf_put_u64(cert, k->cert->valid_before)) != 0 || 2351 (ret = sshbuf_put_stringb(cert, k->cert->critical)) != 0 || 2352 (ret = sshbuf_put_stringb(cert, k->cert->extensions)) != 0 || 2353 (ret = sshbuf_put_string(cert, NULL, 0)) != 0 || /* Reserved */ 2354 (ret = sshbuf_put_string(cert, ca_blob, ca_len)) != 0) 2355 goto out; 2356 2357 /* Sign the whole mess */ 2358 if ((ret = signer(ca, &sig_blob, &sig_len, sshbuf_ptr(cert), 2359 sshbuf_len(cert), alg, sk_provider, sk_pin, 0, signer_ctx)) != 0) 2360 goto out; 2361 /* Check and update signature_type against what was actually used */ 2362 if ((ret = sshkey_get_sigtype(sig_blob, sig_len, &sigtype)) != 0) 2363 goto out; 2364 if (alg != NULL && strcmp(alg, sigtype) != 0) { 2365 ret = SSH_ERR_SIGN_ALG_UNSUPPORTED; 2366 goto out; 2367 } 2368 if (k->cert->signature_type == NULL) { 2369 k->cert->signature_type = sigtype; 2370 sigtype = NULL; 2371 } 2372 /* Append signature and we are done */ 2373 if ((ret = sshbuf_put_string(cert, sig_blob, sig_len)) != 0) 2374 goto out; 2375 ret = 0; 2376 out: 2377 if (ret != 0) 2378 sshbuf_reset(cert); 2379 free(sig_blob); 2380 free(ca_blob); 2381 free(sigtype); 2382 sshbuf_free(principals); 2383 return ret; 2384 } 2385 2386 static int 2387 default_key_sign(struct sshkey *key, u_char **sigp, size_t *lenp, 2388 const u_char *data, size_t datalen, 2389 const char *alg, const char *sk_provider, const char *sk_pin, 2390 u_int compat, void *ctx) 2391 { 2392 if (ctx != NULL) 2393 return SSH_ERR_INVALID_ARGUMENT; 2394 return sshkey_sign(key, sigp, lenp, data, datalen, alg, 2395 sk_provider, sk_pin, compat); 2396 } 2397 2398 int 2399 sshkey_certify(struct sshkey *k, struct sshkey *ca, const char *alg, 2400 const char *sk_provider, const char *sk_pin) 2401 { 2402 return sshkey_certify_custom(k, ca, alg, sk_provider, sk_pin, 2403 default_key_sign, NULL); 2404 } 2405 2406 int 2407 sshkey_cert_check_authority(const struct sshkey *k, 2408 int want_host, int wildcard_pattern, uint64_t verify_time, 2409 const char *name, const char **reason) 2410 { 2411 u_int i, principal_matches; 2412 2413 if (reason == NULL) 2414 return SSH_ERR_INVALID_ARGUMENT; 2415 if (!sshkey_is_cert(k)) { 2416 *reason = "Key is not a certificate"; 2417 return SSH_ERR_KEY_CERT_INVALID; 2418 } 2419 if (want_host) { 2420 if (k->cert->type != SSH2_CERT_TYPE_HOST) { 2421 *reason = "Certificate invalid: not a host certificate"; 2422 return SSH_ERR_KEY_CERT_INVALID; 2423 } 2424 } else { 2425 if (k->cert->type != SSH2_CERT_TYPE_USER) { 2426 *reason = "Certificate invalid: not a user certificate"; 2427 return SSH_ERR_KEY_CERT_INVALID; 2428 } 2429 } 2430 if (verify_time < k->cert->valid_after) { 2431 *reason = "Certificate invalid: not yet valid"; 2432 return SSH_ERR_KEY_CERT_INVALID; 2433 } 2434 if (verify_time >= k->cert->valid_before) { 2435 *reason = "Certificate invalid: expired"; 2436 return SSH_ERR_KEY_CERT_INVALID; 2437 } 2438 if (k->cert->nprincipals == 0) { 2439 *reason = "Certificate lacks principal list"; 2440 return SSH_ERR_KEY_CERT_INVALID; 2441 } 2442 if (name == NULL) 2443 return 0; /* principal matching not requested */ 2444 2445 principal_matches = 0; 2446 for (i = 0; i < k->cert->nprincipals; i++) { 2447 if (wildcard_pattern) { 2448 if (match_pattern(name, k->cert->principals[i])) { 2449 principal_matches = 1; 2450 break; 2451 } 2452 } else if (strcmp(name, k->cert->principals[i]) == 0) { 2453 principal_matches = 1; 2454 break; 2455 } 2456 } 2457 if (!principal_matches) { 2458 *reason = "Certificate invalid: name is not a listed " 2459 "principal"; 2460 return SSH_ERR_KEY_CERT_INVALID; 2461 } 2462 return 0; 2463 } 2464 2465 int 2466 sshkey_cert_check_authority_now(const struct sshkey *k, 2467 int want_host, int wildcard_pattern, const char *name, 2468 const char **reason) 2469 { 2470 time_t now; 2471 2472 if ((now = time(NULL)) < 0) { 2473 /* yikes - system clock before epoch! */ 2474 *reason = "Certificate invalid: not yet valid"; 2475 return SSH_ERR_KEY_CERT_INVALID; 2476 } 2477 return sshkey_cert_check_authority(k, want_host, wildcard_pattern, 2478 (uint64_t)now, name, reason); 2479 } 2480 2481 int 2482 sshkey_cert_check_host(const struct sshkey *key, const char *host, 2483 const char *ca_sign_algorithms, const char **reason) 2484 { 2485 int r; 2486 2487 if ((r = sshkey_cert_check_authority_now(key, 1, 1, host, reason)) != 0) 2488 return r; 2489 if (sshbuf_len(key->cert->critical) != 0) { 2490 *reason = "Certificate contains unsupported critical options"; 2491 return SSH_ERR_KEY_CERT_INVALID; 2492 } 2493 if (ca_sign_algorithms != NULL && 2494 (r = sshkey_check_cert_sigtype(key, ca_sign_algorithms)) != 0) { 2495 *reason = "Certificate signed with disallowed algorithm"; 2496 return SSH_ERR_KEY_CERT_INVALID; 2497 } 2498 return 0; 2499 } 2500 2501 size_t 2502 sshkey_format_cert_validity(const struct sshkey_cert *cert, char *s, size_t l) 2503 { 2504 char from[32], to[32], ret[128]; 2505 2506 *from = *to = '\0'; 2507 if (cert->valid_after == 0 && 2508 cert->valid_before == 0xffffffffffffffffULL) 2509 return strlcpy(s, "forever", l); 2510 2511 if (cert->valid_after != 0) 2512 format_absolute_time(cert->valid_after, from, sizeof(from)); 2513 if (cert->valid_before != 0xffffffffffffffffULL) 2514 format_absolute_time(cert->valid_before, to, sizeof(to)); 2515 2516 if (cert->valid_after == 0) 2517 snprintf(ret, sizeof(ret), "before %s", to); 2518 else if (cert->valid_before == 0xffffffffffffffffULL) 2519 snprintf(ret, sizeof(ret), "after %s", from); 2520 else 2521 snprintf(ret, sizeof(ret), "from %s to %s", from, to); 2522 2523 return strlcpy(s, ret, l); 2524 } 2525 2526 /* Common serialization for FIDO private keys */ 2527 int 2528 sshkey_serialize_private_sk(const struct sshkey *key, struct sshbuf *b) 2529 { 2530 int r; 2531 2532 if ((r = sshbuf_put_cstring(b, key->sk_application)) != 0 || 2533 (r = sshbuf_put_u8(b, key->sk_flags)) != 0 || 2534 (r = sshbuf_put_stringb(b, key->sk_key_handle)) != 0 || 2535 (r = sshbuf_put_stringb(b, key->sk_reserved)) != 0) 2536 return r; 2537 2538 return 0; 2539 } 2540 2541 static int 2542 sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf, 2543 enum sshkey_serialize_rep opts) 2544 { 2545 int r = SSH_ERR_INTERNAL_ERROR; 2546 int was_shielded = sshkey_is_shielded(key); 2547 struct sshbuf *b = NULL; 2548 const struct sshkey_impl *impl; 2549 2550 if ((impl = sshkey_impl_from_key(key)) == NULL) 2551 return SSH_ERR_INTERNAL_ERROR; 2552 if ((r = sshkey_unshield_private(key)) != 0) 2553 return r; 2554 if ((b = sshbuf_new()) == NULL) 2555 return SSH_ERR_ALLOC_FAIL; 2556 if ((r = sshbuf_put_cstring(b, sshkey_ssh_name(key))) != 0) 2557 goto out; 2558 if (sshkey_is_cert(key)) { 2559 if (key->cert == NULL || 2560 sshbuf_len(key->cert->certblob) == 0) { 2561 r = SSH_ERR_INVALID_ARGUMENT; 2562 goto out; 2563 } 2564 if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0) 2565 goto out; 2566 } 2567 if ((r = impl->funcs->serialize_private(key, b, opts)) != 0) 2568 goto out; 2569 2570 /* 2571 * success (but we still need to append the output to buf after 2572 * possibly re-shielding the private key) 2573 */ 2574 r = 0; 2575 out: 2576 if (was_shielded) 2577 r = sshkey_shield_private(key); 2578 if (r == 0) 2579 r = sshbuf_putb(buf, b); 2580 sshbuf_free(b); 2581 2582 return r; 2583 } 2584 2585 int 2586 sshkey_private_serialize(struct sshkey *key, struct sshbuf *b) 2587 { 2588 return sshkey_private_serialize_opt(key, b, 2589 SSHKEY_SERIALIZE_DEFAULT); 2590 } 2591 2592 2593 /* Shared deserialization of FIDO private key components */ 2594 int 2595 sshkey_private_deserialize_sk(struct sshbuf *buf, struct sshkey *k) 2596 { 2597 int r; 2598 2599 if ((k->sk_key_handle = sshbuf_new()) == NULL || 2600 (k->sk_reserved = sshbuf_new()) == NULL) 2601 return SSH_ERR_ALLOC_FAIL; 2602 if ((r = sshbuf_get_cstring(buf, &k->sk_application, NULL)) != 0 || 2603 (r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 || 2604 (r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 || 2605 (r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0) 2606 return r; 2607 2608 return 0; 2609 } 2610 2611 int 2612 sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp) 2613 { 2614 const struct sshkey_impl *impl; 2615 char *tname = NULL; 2616 char *expect_sk_application = NULL; 2617 u_char *expect_ed25519_pk = NULL; 2618 struct sshkey *k = NULL; 2619 int type, r = SSH_ERR_INTERNAL_ERROR; 2620 2621 if (kp != NULL) 2622 *kp = NULL; 2623 if ((r = sshbuf_get_cstring(buf, &tname, NULL)) != 0) 2624 goto out; 2625 type = sshkey_type_from_name(tname); 2626 if (sshkey_type_is_cert(type)) { 2627 /* 2628 * Certificate key private keys begin with the certificate 2629 * itself. Make sure this matches the type of the enclosing 2630 * private key. 2631 */ 2632 if ((r = sshkey_froms(buf, &k)) != 0) 2633 goto out; 2634 if (k->type != type) { 2635 r = SSH_ERR_KEY_CERT_MISMATCH; 2636 goto out; 2637 } 2638 /* For ECDSA keys, the group must match too */ 2639 if (k->type == KEY_ECDSA && 2640 k->ecdsa_nid != sshkey_ecdsa_nid_from_name(tname)) { 2641 r = SSH_ERR_KEY_CERT_MISMATCH; 2642 goto out; 2643 } 2644 /* 2645 * Several fields are redundant between certificate and 2646 * private key body, we require these to match. 2647 */ 2648 expect_sk_application = k->sk_application; 2649 expect_ed25519_pk = k->ed25519_pk; 2650 k->sk_application = NULL; 2651 k->ed25519_pk = NULL; 2652 } else { 2653 if ((k = sshkey_new(type)) == NULL) { 2654 r = SSH_ERR_ALLOC_FAIL; 2655 goto out; 2656 } 2657 } 2658 if ((impl = sshkey_impl_from_type(type)) == NULL) { 2659 r = SSH_ERR_INTERNAL_ERROR; 2660 goto out; 2661 } 2662 if ((r = impl->funcs->deserialize_private(tname, buf, k)) != 0) 2663 goto out; 2664 2665 if ((expect_sk_application != NULL && (k->sk_application == NULL || 2666 strcmp(expect_sk_application, k->sk_application) != 0)) || 2667 (expect_ed25519_pk != NULL && (k->ed25519_pk == NULL || 2668 memcmp(expect_ed25519_pk, k->ed25519_pk, ED25519_PK_SZ) != 0))) { 2669 r = SSH_ERR_KEY_CERT_MISMATCH; 2670 goto out; 2671 } 2672 /* success */ 2673 r = 0; 2674 if (kp != NULL) { 2675 *kp = k; 2676 k = NULL; 2677 } 2678 out: 2679 free(tname); 2680 sshkey_free(k); 2681 free(expect_sk_application); 2682 free(expect_ed25519_pk); 2683 return r; 2684 } 2685 2686 #ifdef WITH_OPENSSL 2687 int 2688 sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public) 2689 { 2690 EC_POINT *nq = NULL; 2691 BIGNUM *order = NULL, *cofactor = NULL; 2692 int ret = SSH_ERR_KEY_INVALID_EC_VALUE; 2693 2694 /* 2695 * NB. This assumes OpenSSL has already verified that the public 2696 * point lies on the curve and that its coordinates are in [0, p). 2697 * This is done by EC_POINT_oct2point() on at least OpenSSL >= 1.1, 2698 * LibreSSL and BoringSSL. 2699 */ 2700 2701 /* Q != infinity */ 2702 if (EC_POINT_is_at_infinity(group, public)) 2703 goto out; 2704 2705 if ((cofactor = BN_new()) == NULL) { 2706 ret = SSH_ERR_ALLOC_FAIL; 2707 goto out; 2708 } 2709 if (EC_GROUP_get_cofactor(group, cofactor, NULL) != 1) 2710 goto out; 2711 2712 /* 2713 * Verify nQ == infinity (n == order of subgroup) 2714 * This check may be skipped for curves with cofactor 1, as per 2715 * NIST SP 800-56A, 5.6.2.3. 2716 */ 2717 if (!BN_is_one(cofactor)) { 2718 if ((order = BN_new()) == NULL) { 2719 ret = SSH_ERR_ALLOC_FAIL; 2720 goto out; 2721 } 2722 if (EC_GROUP_get_order(group, order, NULL) != 1) { 2723 ret = SSH_ERR_LIBCRYPTO_ERROR; 2724 goto out; 2725 } 2726 if ((nq = EC_POINT_new(group)) == NULL) { 2727 ret = SSH_ERR_ALLOC_FAIL; 2728 goto out; 2729 } 2730 if (EC_POINT_mul(group, nq, NULL, public, order, NULL) != 1) { 2731 ret = SSH_ERR_LIBCRYPTO_ERROR; 2732 goto out; 2733 } 2734 if (EC_POINT_is_at_infinity(group, nq) != 1) 2735 goto out; 2736 } 2737 2738 /* success */ 2739 ret = 0; 2740 out: 2741 BN_clear_free(cofactor); 2742 BN_clear_free(order); 2743 EC_POINT_free(nq); 2744 return ret; 2745 } 2746 2747 int 2748 sshkey_ec_validate_private(const EC_KEY *key) 2749 { 2750 BIGNUM *order = NULL, *tmp = NULL; 2751 int ret = SSH_ERR_KEY_INVALID_EC_VALUE; 2752 2753 if ((order = BN_new()) == NULL || (tmp = BN_new()) == NULL) { 2754 ret = SSH_ERR_ALLOC_FAIL; 2755 goto out; 2756 } 2757 2758 /* log2(private) > log2(order)/2 */ 2759 if (EC_GROUP_get_order(EC_KEY_get0_group(key), order, NULL) != 1) { 2760 ret = SSH_ERR_LIBCRYPTO_ERROR; 2761 goto out; 2762 } 2763 if (BN_num_bits(EC_KEY_get0_private_key(key)) <= 2764 BN_num_bits(order) / 2) 2765 goto out; 2766 2767 /* private < order - 1 */ 2768 if (!BN_sub(tmp, order, BN_value_one())) { 2769 ret = SSH_ERR_LIBCRYPTO_ERROR; 2770 goto out; 2771 } 2772 if (BN_cmp(EC_KEY_get0_private_key(key), tmp) >= 0) 2773 goto out; 2774 ret = 0; 2775 out: 2776 BN_clear_free(order); 2777 BN_clear_free(tmp); 2778 return ret; 2779 } 2780 2781 void 2782 sshkey_dump_ec_point(const EC_GROUP *group, const EC_POINT *point) 2783 { 2784 BIGNUM *x = NULL, *y = NULL; 2785 2786 if (point == NULL) { 2787 fputs("point=(NULL)\n", stderr); 2788 return; 2789 } 2790 if ((x = BN_new()) == NULL || (y = BN_new()) == NULL) { 2791 fprintf(stderr, "%s: BN_new failed\n", __func__); 2792 goto out; 2793 } 2794 if (EC_POINT_get_affine_coordinates(group, point, x, y, NULL) != 1) { 2795 fprintf(stderr, "%s: EC_POINT_get_affine_coordinates\n", 2796 __func__); 2797 goto out; 2798 } 2799 fputs("x=", stderr); 2800 BN_print_fp(stderr, x); 2801 fputs("\ny=", stderr); 2802 BN_print_fp(stderr, y); 2803 fputs("\n", stderr); 2804 out: 2805 BN_clear_free(x); 2806 BN_clear_free(y); 2807 } 2808 2809 void 2810 sshkey_dump_ec_key(const EC_KEY *key) 2811 { 2812 const BIGNUM *exponent; 2813 2814 sshkey_dump_ec_point(EC_KEY_get0_group(key), 2815 EC_KEY_get0_public_key(key)); 2816 fputs("exponent=", stderr); 2817 if ((exponent = EC_KEY_get0_private_key(key)) == NULL) 2818 fputs("(NULL)", stderr); 2819 else 2820 BN_print_fp(stderr, EC_KEY_get0_private_key(key)); 2821 fputs("\n", stderr); 2822 } 2823 #endif /* WITH_OPENSSL */ 2824 2825 static int 2826 sshkey_private_to_blob2(struct sshkey *prv, struct sshbuf *blob, 2827 const char *passphrase, const char *comment, const char *ciphername, 2828 int rounds) 2829 { 2830 u_char *cp, *key = NULL, *pubkeyblob = NULL; 2831 u_char salt[SALT_LEN]; 2832 size_t i, pubkeylen, keylen, ivlen, blocksize, authlen; 2833 u_int check; 2834 int r = SSH_ERR_INTERNAL_ERROR; 2835 struct sshcipher_ctx *ciphercontext = NULL; 2836 const struct sshcipher *cipher; 2837 const char *kdfname = KDFNAME; 2838 struct sshbuf *encoded = NULL, *encrypted = NULL, *kdf = NULL; 2839 2840 if (rounds <= 0) 2841 rounds = DEFAULT_ROUNDS; 2842 if (rounds > MAX_KDF_ROUNDS) { 2843 r = SSH_ERR_INVALID_ARGUMENT; 2844 goto out; 2845 } 2846 if (passphrase == NULL || !strlen(passphrase)) { 2847 ciphername = "none"; 2848 kdfname = "none"; 2849 } else if (ciphername == NULL) 2850 ciphername = DEFAULT_CIPHERNAME; 2851 if ((cipher = cipher_by_name(ciphername)) == NULL) { 2852 r = SSH_ERR_INVALID_ARGUMENT; 2853 goto out; 2854 } 2855 2856 if ((kdf = sshbuf_new()) == NULL || 2857 (encoded = sshbuf_new()) == NULL || 2858 (encrypted = sshbuf_new()) == NULL) { 2859 r = SSH_ERR_ALLOC_FAIL; 2860 goto out; 2861 } 2862 blocksize = cipher_blocksize(cipher); 2863 keylen = cipher_keylen(cipher); 2864 ivlen = cipher_ivlen(cipher); 2865 authlen = cipher_authlen(cipher); 2866 if ((key = calloc(1, keylen + ivlen)) == NULL) { 2867 r = SSH_ERR_ALLOC_FAIL; 2868 goto out; 2869 } 2870 if (strcmp(kdfname, "bcrypt") == 0) { 2871 arc4random_buf(salt, SALT_LEN); 2872 if (bcrypt_pbkdf(passphrase, strlen(passphrase), 2873 salt, SALT_LEN, key, keylen + ivlen, rounds) < 0) { 2874 r = SSH_ERR_INVALID_ARGUMENT; 2875 goto out; 2876 } 2877 if ((r = sshbuf_put_string(kdf, salt, SALT_LEN)) != 0 || 2878 (r = sshbuf_put_u32(kdf, rounds)) != 0) 2879 goto out; 2880 } else if (strcmp(kdfname, "none") != 0) { 2881 /* Unsupported KDF type */ 2882 r = SSH_ERR_KEY_UNKNOWN_CIPHER; 2883 goto out; 2884 } 2885 if ((r = cipher_init(&ciphercontext, cipher, key, keylen, 2886 key + keylen, ivlen, 1)) != 0) 2887 goto out; 2888 2889 if ((r = sshbuf_put(encoded, AUTH_MAGIC, sizeof(AUTH_MAGIC))) != 0 || 2890 (r = sshbuf_put_cstring(encoded, ciphername)) != 0 || 2891 (r = sshbuf_put_cstring(encoded, kdfname)) != 0 || 2892 (r = sshbuf_put_stringb(encoded, kdf)) != 0 || 2893 (r = sshbuf_put_u32(encoded, 1)) != 0 || /* number of keys */ 2894 (r = sshkey_to_blob(prv, &pubkeyblob, &pubkeylen)) != 0 || 2895 (r = sshbuf_put_string(encoded, pubkeyblob, pubkeylen)) != 0) 2896 goto out; 2897 2898 /* set up the buffer that will be encrypted */ 2899 2900 /* Random check bytes */ 2901 check = arc4random(); 2902 if ((r = sshbuf_put_u32(encrypted, check)) != 0 || 2903 (r = sshbuf_put_u32(encrypted, check)) != 0) 2904 goto out; 2905 2906 /* append private key and comment*/ 2907 if ((r = sshkey_private_serialize(prv, encrypted)) != 0 || 2908 (r = sshbuf_put_cstring(encrypted, comment)) != 0) 2909 goto out; 2910 2911 /* padding */ 2912 i = 0; 2913 while (sshbuf_len(encrypted) % blocksize) { 2914 if ((r = sshbuf_put_u8(encrypted, ++i & 0xff)) != 0) 2915 goto out; 2916 } 2917 2918 /* length in destination buffer */ 2919 if ((r = sshbuf_put_u32(encoded, sshbuf_len(encrypted))) != 0) 2920 goto out; 2921 2922 /* encrypt */ 2923 if ((r = sshbuf_reserve(encoded, 2924 sshbuf_len(encrypted) + authlen, &cp)) != 0) 2925 goto out; 2926 if ((r = cipher_crypt(ciphercontext, 0, cp, 2927 sshbuf_ptr(encrypted), sshbuf_len(encrypted), 0, authlen)) != 0) 2928 goto out; 2929 2930 sshbuf_reset(blob); 2931 2932 /* assemble uuencoded key */ 2933 if ((r = sshbuf_put(blob, MARK_BEGIN, MARK_BEGIN_LEN)) != 0 || 2934 (r = sshbuf_dtob64(encoded, blob, 1)) != 0 || 2935 (r = sshbuf_put(blob, MARK_END, MARK_END_LEN)) != 0) 2936 goto out; 2937 2938 /* success */ 2939 r = 0; 2940 2941 out: 2942 sshbuf_free(kdf); 2943 sshbuf_free(encoded); 2944 sshbuf_free(encrypted); 2945 cipher_free(ciphercontext); 2946 explicit_bzero(salt, sizeof(salt)); 2947 if (key != NULL) 2948 freezero(key, keylen + ivlen); 2949 if (pubkeyblob != NULL) 2950 freezero(pubkeyblob, pubkeylen); 2951 return r; 2952 } 2953 2954 static int 2955 private2_uudecode(struct sshbuf *blob, struct sshbuf **decodedp) 2956 { 2957 const u_char *cp; 2958 size_t encoded_len; 2959 int r; 2960 u_char last; 2961 struct sshbuf *encoded = NULL, *decoded = NULL; 2962 2963 if (blob == NULL || decodedp == NULL) 2964 return SSH_ERR_INVALID_ARGUMENT; 2965 2966 *decodedp = NULL; 2967 2968 if ((encoded = sshbuf_new()) == NULL || 2969 (decoded = sshbuf_new()) == NULL) { 2970 r = SSH_ERR_ALLOC_FAIL; 2971 goto out; 2972 } 2973 2974 /* check preamble */ 2975 cp = sshbuf_ptr(blob); 2976 encoded_len = sshbuf_len(blob); 2977 if (encoded_len < (MARK_BEGIN_LEN + MARK_END_LEN) || 2978 memcmp(cp, MARK_BEGIN, MARK_BEGIN_LEN) != 0) { 2979 r = SSH_ERR_INVALID_FORMAT; 2980 goto out; 2981 } 2982 cp += MARK_BEGIN_LEN; 2983 encoded_len -= MARK_BEGIN_LEN; 2984 2985 /* Look for end marker, removing whitespace as we go */ 2986 while (encoded_len > 0) { 2987 if (*cp != '\n' && *cp != '\r') { 2988 if ((r = sshbuf_put_u8(encoded, *cp)) != 0) 2989 goto out; 2990 } 2991 last = *cp; 2992 encoded_len--; 2993 cp++; 2994 if (last == '\n') { 2995 if (encoded_len >= MARK_END_LEN && 2996 memcmp(cp, MARK_END, MARK_END_LEN) == 0) { 2997 /* \0 terminate */ 2998 if ((r = sshbuf_put_u8(encoded, 0)) != 0) 2999 goto out; 3000 break; 3001 } 3002 } 3003 } 3004 if (encoded_len == 0) { 3005 r = SSH_ERR_INVALID_FORMAT; 3006 goto out; 3007 } 3008 3009 /* decode base64 */ 3010 if ((r = sshbuf_b64tod(decoded, (const char *)sshbuf_ptr(encoded))) != 0) 3011 goto out; 3012 3013 /* check magic */ 3014 if (sshbuf_len(decoded) < sizeof(AUTH_MAGIC) || 3015 memcmp(sshbuf_ptr(decoded), AUTH_MAGIC, sizeof(AUTH_MAGIC))) { 3016 r = SSH_ERR_INVALID_FORMAT; 3017 goto out; 3018 } 3019 /* success */ 3020 *decodedp = decoded; 3021 decoded = NULL; 3022 r = 0; 3023 out: 3024 sshbuf_free(encoded); 3025 sshbuf_free(decoded); 3026 return r; 3027 } 3028 3029 static int 3030 private2_decrypt(struct sshbuf *decoded, const char *passphrase, 3031 struct sshbuf **decryptedp, struct sshkey **pubkeyp) 3032 { 3033 char *ciphername = NULL, *kdfname = NULL; 3034 const struct sshcipher *cipher = NULL; 3035 int r = SSH_ERR_INTERNAL_ERROR; 3036 size_t keylen = 0, ivlen = 0, authlen = 0, slen = 0; 3037 struct sshbuf *kdf = NULL, *decrypted = NULL; 3038 struct sshcipher_ctx *ciphercontext = NULL; 3039 struct sshkey *pubkey = NULL; 3040 u_char *key = NULL, *salt = NULL, *dp; 3041 u_int blocksize, rounds, nkeys, encrypted_len, check1, check2; 3042 3043 if (decoded == NULL || decryptedp == NULL || pubkeyp == NULL) 3044 return SSH_ERR_INVALID_ARGUMENT; 3045 3046 *decryptedp = NULL; 3047 *pubkeyp = NULL; 3048 3049 if ((decrypted = sshbuf_new()) == NULL) { 3050 r = SSH_ERR_ALLOC_FAIL; 3051 goto out; 3052 } 3053 3054 /* parse public portion of key */ 3055 if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 || 3056 (r = sshbuf_get_cstring(decoded, &ciphername, NULL)) != 0 || 3057 (r = sshbuf_get_cstring(decoded, &kdfname, NULL)) != 0 || 3058 (r = sshbuf_froms(decoded, &kdf)) != 0 || 3059 (r = sshbuf_get_u32(decoded, &nkeys)) != 0) 3060 goto out; 3061 3062 if (nkeys != 1) { 3063 /* XXX only one key supported at present */ 3064 r = SSH_ERR_INVALID_FORMAT; 3065 goto out; 3066 } 3067 3068 if ((r = sshkey_froms(decoded, &pubkey)) != 0 || 3069 (r = sshbuf_get_u32(decoded, &encrypted_len)) != 0) 3070 goto out; 3071 3072 if ((cipher = cipher_by_name(ciphername)) == NULL) { 3073 r = SSH_ERR_KEY_UNKNOWN_CIPHER; 3074 goto out; 3075 } 3076 if (strcmp(kdfname, "none") != 0 && strcmp(kdfname, "bcrypt") != 0) { 3077 r = SSH_ERR_KEY_UNKNOWN_CIPHER; 3078 goto out; 3079 } 3080 if (strcmp(kdfname, "none") == 0 && strcmp(ciphername, "none") != 0) { 3081 r = SSH_ERR_INVALID_FORMAT; 3082 goto out; 3083 } 3084 if ((passphrase == NULL || strlen(passphrase) == 0) && 3085 strcmp(kdfname, "none") != 0) { 3086 /* passphrase required */ 3087 r = SSH_ERR_KEY_WRONG_PASSPHRASE; 3088 goto out; 3089 } 3090 3091 /* check size of encrypted key blob */ 3092 blocksize = cipher_blocksize(cipher); 3093 if (encrypted_len < blocksize || (encrypted_len % blocksize) != 0) { 3094 r = SSH_ERR_INVALID_FORMAT; 3095 goto out; 3096 } 3097 3098 /* setup key */ 3099 keylen = cipher_keylen(cipher); 3100 ivlen = cipher_ivlen(cipher); 3101 authlen = cipher_authlen(cipher); 3102 if ((key = calloc(1, keylen + ivlen)) == NULL) { 3103 r = SSH_ERR_ALLOC_FAIL; 3104 goto out; 3105 } 3106 if (strcmp(kdfname, "bcrypt") == 0) { 3107 if ((r = sshbuf_get_string(kdf, &salt, &slen)) != 0 || 3108 (r = sshbuf_get_u32(kdf, &rounds)) != 0) 3109 goto out; 3110 if (rounds > MAX_KDF_ROUNDS) { 3111 r = SSH_ERR_INVALID_FORMAT; 3112 goto out; 3113 } 3114 if (bcrypt_pbkdf(passphrase, strlen(passphrase), salt, slen, 3115 key, keylen + ivlen, rounds) < 0) { 3116 r = SSH_ERR_INVALID_FORMAT; 3117 goto out; 3118 } 3119 } 3120 3121 /* check that an appropriate amount of auth data is present */ 3122 if (sshbuf_len(decoded) < authlen || 3123 sshbuf_len(decoded) - authlen < encrypted_len) { 3124 r = SSH_ERR_INVALID_FORMAT; 3125 goto out; 3126 } 3127 3128 /* decrypt private portion of key */ 3129 if ((r = sshbuf_reserve(decrypted, encrypted_len, &dp)) != 0 || 3130 (r = cipher_init(&ciphercontext, cipher, key, keylen, 3131 key + keylen, ivlen, 0)) != 0) 3132 goto out; 3133 if ((r = cipher_crypt(ciphercontext, 0, dp, sshbuf_ptr(decoded), 3134 encrypted_len, 0, authlen)) != 0) { 3135 /* an integrity error here indicates an incorrect passphrase */ 3136 if (r == SSH_ERR_MAC_INVALID) 3137 r = SSH_ERR_KEY_WRONG_PASSPHRASE; 3138 goto out; 3139 } 3140 if ((r = sshbuf_consume(decoded, encrypted_len + authlen)) != 0) 3141 goto out; 3142 /* there should be no trailing data */ 3143 if (sshbuf_len(decoded) != 0) { 3144 r = SSH_ERR_INVALID_FORMAT; 3145 goto out; 3146 } 3147 3148 /* check check bytes */ 3149 if ((r = sshbuf_get_u32(decrypted, &check1)) != 0 || 3150 (r = sshbuf_get_u32(decrypted, &check2)) != 0) 3151 goto out; 3152 if (check1 != check2) { 3153 r = SSH_ERR_KEY_WRONG_PASSPHRASE; 3154 goto out; 3155 } 3156 /* success */ 3157 *decryptedp = decrypted; 3158 decrypted = NULL; 3159 *pubkeyp = pubkey; 3160 pubkey = NULL; 3161 r = 0; 3162 out: 3163 cipher_free(ciphercontext); 3164 free(ciphername); 3165 free(kdfname); 3166 sshkey_free(pubkey); 3167 if (salt != NULL) { 3168 explicit_bzero(salt, slen); 3169 free(salt); 3170 } 3171 if (key != NULL) { 3172 explicit_bzero(key, keylen + ivlen); 3173 free(key); 3174 } 3175 sshbuf_free(kdf); 3176 sshbuf_free(decrypted); 3177 return r; 3178 } 3179 3180 static int 3181 sshkey_parse_private2(struct sshbuf *blob, int type, const char *passphrase, 3182 struct sshkey **keyp, char **commentp) 3183 { 3184 char *comment = NULL; 3185 int r = SSH_ERR_INTERNAL_ERROR; 3186 struct sshbuf *decoded = NULL, *decrypted = NULL; 3187 struct sshkey *k = NULL, *pubkey = NULL; 3188 3189 if (keyp != NULL) 3190 *keyp = NULL; 3191 if (commentp != NULL) 3192 *commentp = NULL; 3193 3194 /* Undo base64 encoding and decrypt the private section */ 3195 if ((r = private2_uudecode(blob, &decoded)) != 0 || 3196 (r = private2_decrypt(decoded, passphrase, 3197 &decrypted, &pubkey)) != 0) 3198 goto out; 3199 3200 if (type != KEY_UNSPEC && 3201 sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) { 3202 r = SSH_ERR_KEY_TYPE_MISMATCH; 3203 goto out; 3204 } 3205 3206 /* Load the private key and comment */ 3207 if ((r = sshkey_private_deserialize(decrypted, &k)) != 0 || 3208 (r = sshbuf_get_cstring(decrypted, &comment, NULL)) != 0) 3209 goto out; 3210 3211 /* Check deterministic padding after private section */ 3212 if ((r = private2_check_padding(decrypted)) != 0) 3213 goto out; 3214 3215 /* Check that the public key in the envelope matches the private key */ 3216 if (!sshkey_equal(pubkey, k)) { 3217 r = SSH_ERR_INVALID_FORMAT; 3218 goto out; 3219 } 3220 3221 /* success */ 3222 r = 0; 3223 if (keyp != NULL) { 3224 *keyp = k; 3225 k = NULL; 3226 } 3227 if (commentp != NULL) { 3228 *commentp = comment; 3229 comment = NULL; 3230 } 3231 out: 3232 free(comment); 3233 sshbuf_free(decoded); 3234 sshbuf_free(decrypted); 3235 sshkey_free(k); 3236 sshkey_free(pubkey); 3237 return r; 3238 } 3239 3240 static int 3241 sshkey_parse_private2_pubkey(struct sshbuf *blob, int type, 3242 struct sshkey **keyp) 3243 { 3244 int r = SSH_ERR_INTERNAL_ERROR; 3245 struct sshbuf *decoded = NULL; 3246 struct sshkey *pubkey = NULL; 3247 u_int nkeys = 0; 3248 3249 if (keyp != NULL) 3250 *keyp = NULL; 3251 3252 if ((r = private2_uudecode(blob, &decoded)) != 0) 3253 goto out; 3254 /* parse public key from unencrypted envelope */ 3255 if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 || 3256 (r = sshbuf_skip_string(decoded)) != 0 || /* cipher */ 3257 (r = sshbuf_skip_string(decoded)) != 0 || /* KDF alg */ 3258 (r = sshbuf_skip_string(decoded)) != 0 || /* KDF hint */ 3259 (r = sshbuf_get_u32(decoded, &nkeys)) != 0) 3260 goto out; 3261 3262 if (nkeys != 1) { 3263 /* XXX only one key supported at present */ 3264 r = SSH_ERR_INVALID_FORMAT; 3265 goto out; 3266 } 3267 3268 /* Parse the public key */ 3269 if ((r = sshkey_froms(decoded, &pubkey)) != 0) 3270 goto out; 3271 3272 if (type != KEY_UNSPEC && 3273 sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) { 3274 r = SSH_ERR_KEY_TYPE_MISMATCH; 3275 goto out; 3276 } 3277 3278 /* success */ 3279 r = 0; 3280 if (keyp != NULL) { 3281 *keyp = pubkey; 3282 pubkey = NULL; 3283 } 3284 out: 3285 sshbuf_free(decoded); 3286 sshkey_free(pubkey); 3287 return r; 3288 } 3289 3290 #ifdef WITH_OPENSSL 3291 /* convert SSH v2 key to PEM or PKCS#8 format */ 3292 static int 3293 sshkey_private_to_blob_pem_pkcs8(struct sshkey *key, struct sshbuf *buf, 3294 int format, const char *_passphrase, const char *comment) 3295 { 3296 int was_shielded = sshkey_is_shielded(key); 3297 int success, r; 3298 int blen, len = strlen(_passphrase); 3299 u_char *passphrase = (len > 0) ? __UNCONST(_passphrase) : NULL; 3300 const EVP_CIPHER *cipher = (len > 0) ? EVP_aes_128_cbc() : NULL; 3301 char *bptr; 3302 BIO *bio = NULL; 3303 struct sshbuf *blob; 3304 EVP_PKEY *pkey = NULL; 3305 3306 if (len > 0 && len <= 4) 3307 return SSH_ERR_PASSPHRASE_TOO_SHORT; 3308 if ((blob = sshbuf_new()) == NULL) 3309 return SSH_ERR_ALLOC_FAIL; 3310 if ((bio = BIO_new(BIO_s_mem())) == NULL) { 3311 r = SSH_ERR_ALLOC_FAIL; 3312 goto out; 3313 } 3314 if ((r = sshkey_unshield_private(key)) != 0) 3315 goto out; 3316 3317 switch (key->type) { 3318 case KEY_ECDSA: 3319 if (format == SSHKEY_PRIVATE_PEM) { 3320 success = PEM_write_bio_ECPrivateKey(bio, 3321 EVP_PKEY_get0_EC_KEY(key->pkey), 3322 cipher, passphrase, len, NULL, NULL); 3323 } else { 3324 pkey = key->pkey; 3325 EVP_PKEY_up_ref(key->pkey); 3326 success = 1; 3327 } 3328 break; 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 case PEM_R_PROBLEMS_GETTING_PASSWORD: 3440 case PEM_R_BAD_DECRYPT: 3441 return SSH_ERR_KEY_WRONG_PASSPHRASE; 3442 default: 3443 return SSH_ERR_INVALID_FORMAT; 3444 } 3445 case ERR_LIB_EVP: 3446 switch (pem_reason) { 3447 case EVP_R_BAD_DECRYPT: 3448 return SSH_ERR_KEY_WRONG_PASSPHRASE; 3449 #ifdef EVP_R_BN_DECODE_ERROR 3450 case EVP_R_BN_DECODE_ERROR: 3451 #endif 3452 case EVP_R_DECODE_ERROR: 3453 #ifdef EVP_R_PRIVATE_KEY_DECODE_ERROR 3454 case EVP_R_PRIVATE_KEY_DECODE_ERROR: 3455 #endif 3456 return SSH_ERR_INVALID_FORMAT; 3457 default: 3458 return SSH_ERR_LIBCRYPTO_ERROR; 3459 } 3460 case ERR_LIB_ASN1: 3461 return SSH_ERR_INVALID_FORMAT; 3462 } 3463 return SSH_ERR_LIBCRYPTO_ERROR; 3464 } 3465 3466 static void 3467 clear_libcrypto_errors(void) 3468 { 3469 while (ERR_get_error() != 0) 3470 ; 3471 } 3472 3473 /* 3474 * Translate OpenSSL error codes to determine whether 3475 * passphrase is required/incorrect. 3476 */ 3477 static int 3478 convert_libcrypto_error(void) 3479 { 3480 /* 3481 * Some password errors are reported at the beginning 3482 * of the error queue. 3483 */ 3484 if (translate_libcrypto_error(ERR_peek_error()) == 3485 SSH_ERR_KEY_WRONG_PASSPHRASE) 3486 return SSH_ERR_KEY_WRONG_PASSPHRASE; 3487 return translate_libcrypto_error(ERR_peek_last_error()); 3488 } 3489 3490 #if 0 3491 static int 3492 pem_passphrase_cb(char *buf, int size, int rwflag, void *u) 3493 { 3494 char *p = (char *)u; 3495 size_t len; 3496 3497 if (p == NULL || (len = strlen(p)) == 0) 3498 return -1; 3499 if (size < 0 || len > (size_t)size) 3500 return -1; 3501 memcpy(buf, p, len); 3502 return (int)len; 3503 } 3504 #endif 3505 3506 static int 3507 sshkey_parse_private_pem_fileblob(struct sshbuf *blob, int type, 3508 const char *passphrase, struct sshkey **keyp) 3509 { 3510 EVP_PKEY *pk = NULL; 3511 struct sshkey *prv = NULL; 3512 BIO *bio = NULL; 3513 int r; 3514 RSA *rsa = NULL; 3515 EC_KEY *ecdsa = NULL; 3516 3517 if (keyp != NULL) 3518 *keyp = NULL; 3519 3520 if ((bio = BIO_new(BIO_s_mem())) == NULL || sshbuf_len(blob) > INT_MAX) 3521 return SSH_ERR_ALLOC_FAIL; 3522 if (BIO_write(bio, sshbuf_ptr(blob), sshbuf_len(blob)) != 3523 (int)sshbuf_len(blob)) { 3524 r = SSH_ERR_ALLOC_FAIL; 3525 goto out; 3526 } 3527 3528 clear_libcrypto_errors(); 3529 if ((pk = PEM_read_bio_PrivateKey(bio, NULL, NULL, 3530 __UNCONST(passphrase))) == NULL) { 3531 /* 3532 * libcrypto may return various ASN.1 errors when attempting 3533 * to parse a key with an incorrect passphrase. 3534 * Treat all format errors as "incorrect passphrase" if a 3535 * passphrase was supplied. 3536 */ 3537 if (passphrase != NULL && *passphrase != '\0') 3538 r = SSH_ERR_KEY_WRONG_PASSPHRASE; 3539 else 3540 r = convert_libcrypto_error(); 3541 goto out; 3542 } 3543 if (EVP_PKEY_base_id(pk) == EVP_PKEY_RSA && 3544 (type == KEY_UNSPEC || type == KEY_RSA)) { 3545 if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) { 3546 r = SSH_ERR_ALLOC_FAIL; 3547 goto out; 3548 } 3549 if ((rsa = EVP_PKEY_get1_RSA(pk)) == NULL) { 3550 r = SSH_ERR_LIBCRYPTO_ERROR; 3551 goto out; 3552 } 3553 prv->type = KEY_RSA; 3554 #ifdef DEBUG_PK 3555 RSA_print_fp(stderr, rsa, 8); 3556 #endif 3557 if (RSA_blinding_on(rsa, NULL) != 1 || 3558 EVP_PKEY_set1_RSA(pk, rsa) != 1) { 3559 r = SSH_ERR_LIBCRYPTO_ERROR; 3560 goto out; 3561 } 3562 EVP_PKEY_up_ref(pk); 3563 prv->pkey = pk; 3564 if ((r = sshkey_check_rsa_length(prv, 0)) != 0) 3565 goto out; 3566 } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_EC && 3567 (type == KEY_UNSPEC || type == KEY_ECDSA)) { 3568 if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) { 3569 r = SSH_ERR_ALLOC_FAIL; 3570 goto out; 3571 } 3572 if ((prv->ecdsa_nid = sshkey_ecdsa_fixup_group(pk)) == -1 || 3573 (ecdsa = EVP_PKEY_get1_EC_KEY(pk)) == NULL) { 3574 r = SSH_ERR_LIBCRYPTO_ERROR; 3575 goto out; 3576 } 3577 prv->type = KEY_ECDSA; 3578 if (sshkey_curve_nid_to_name(prv->ecdsa_nid) == NULL || 3579 sshkey_ec_validate_public(EC_KEY_get0_group(ecdsa), 3580 EC_KEY_get0_public_key(ecdsa)) != 0 || 3581 sshkey_ec_validate_private(ecdsa) != 0) { 3582 r = SSH_ERR_INVALID_FORMAT; 3583 goto out; 3584 } 3585 EVP_PKEY_up_ref(pk); 3586 prv->pkey = pk; 3587 #ifdef DEBUG_PK 3588 if (prv != NULL && prv->pkey != NULL) 3589 sshkey_dump_ec_key(EVP_PKEY_get0_EC_KEY(prv->pkey)); 3590 #endif 3591 } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_ED25519 && 3592 (type == KEY_UNSPEC || type == KEY_ED25519)) { 3593 size_t len; 3594 3595 if ((prv = sshkey_new(KEY_UNSPEC)) == NULL || 3596 (prv->ed25519_sk = calloc(1, ED25519_SK_SZ)) == NULL || 3597 (prv->ed25519_pk = calloc(1, ED25519_PK_SZ)) == NULL) { 3598 r = SSH_ERR_ALLOC_FAIL; 3599 goto out; 3600 } 3601 prv->type = KEY_ED25519; 3602 len = ED25519_PK_SZ; 3603 if (!EVP_PKEY_get_raw_public_key(pk, prv->ed25519_pk, &len)) { 3604 r = SSH_ERR_LIBCRYPTO_ERROR; 3605 goto out; 3606 } 3607 if (len != ED25519_PK_SZ) { 3608 r = SSH_ERR_INVALID_FORMAT; 3609 goto out; 3610 } 3611 len = ED25519_SK_SZ - ED25519_PK_SZ; 3612 if (!EVP_PKEY_get_raw_private_key(pk, prv->ed25519_sk, &len)) { 3613 r = SSH_ERR_LIBCRYPTO_ERROR; 3614 goto out; 3615 } 3616 if (len != ED25519_SK_SZ - ED25519_PK_SZ) { 3617 r = SSH_ERR_INVALID_FORMAT; 3618 goto out; 3619 } 3620 /* Append the public key to our private key */ 3621 memcpy(prv->ed25519_sk + (ED25519_SK_SZ - ED25519_PK_SZ), 3622 prv->ed25519_pk, ED25519_PK_SZ); 3623 #ifdef DEBUG_PK 3624 sshbuf_dump_data(prv->ed25519_sk, ED25519_SK_SZ, stderr); 3625 #endif 3626 } else { 3627 r = SSH_ERR_INVALID_FORMAT; 3628 goto out; 3629 } 3630 r = 0; 3631 if (keyp != NULL) { 3632 *keyp = prv; 3633 prv = NULL; 3634 } 3635 out: 3636 BIO_free(bio); 3637 EVP_PKEY_free(pk); 3638 RSA_free(rsa); 3639 EC_KEY_free(ecdsa); 3640 sshkey_free(prv); 3641 return r; 3642 } 3643 #endif /* WITH_OPENSSL */ 3644 3645 int 3646 sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type, 3647 const char *passphrase, struct sshkey **keyp, char **commentp) 3648 { 3649 int r = SSH_ERR_INTERNAL_ERROR; 3650 3651 if (keyp != NULL) 3652 *keyp = NULL; 3653 if (commentp != NULL) 3654 *commentp = NULL; 3655 3656 r = sshkey_parse_private2(blob, type, passphrase, keyp, commentp); 3657 /* Only fallback to PEM parser if a format error occurred. */ 3658 if (r != SSH_ERR_INVALID_FORMAT) 3659 return r; 3660 #ifdef WITH_OPENSSL 3661 return sshkey_parse_private_pem_fileblob(blob, type, 3662 passphrase, keyp); 3663 #else 3664 return SSH_ERR_INVALID_FORMAT; 3665 #endif /* WITH_OPENSSL */ 3666 } 3667 3668 int 3669 sshkey_parse_private_fileblob(struct sshbuf *buffer, const char *passphrase, 3670 struct sshkey **keyp, char **commentp) 3671 { 3672 if (keyp != NULL) 3673 *keyp = NULL; 3674 if (commentp != NULL) 3675 *commentp = NULL; 3676 3677 return sshkey_parse_private_fileblob_type(buffer, KEY_UNSPEC, 3678 passphrase, keyp, commentp); 3679 } 3680 3681 void 3682 sshkey_sig_details_free(struct sshkey_sig_details *details) 3683 { 3684 freezero(details, sizeof(*details)); 3685 } 3686 3687 int 3688 sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob, int type, 3689 struct sshkey **pubkeyp) 3690 { 3691 int r = SSH_ERR_INTERNAL_ERROR; 3692 3693 if (pubkeyp != NULL) 3694 *pubkeyp = NULL; 3695 /* only new-format private keys bundle a public key inside */ 3696 if ((r = sshkey_parse_private2_pubkey(blob, type, pubkeyp)) != 0) 3697 return r; 3698 return 0; 3699 } 3700
Indexes created Thu Oct 08 00:26:19 UTC 2026