ssh-sk.c revision 1.1.1.6
1 /* $OpenBSD: ssh-sk.c,v 1.39 2022/07/20 03:29:14 djm Exp $ */ 2 /* 3 * Copyright (c) 2019 Google LLC 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 /* #define DEBUG_SK 1 */ 19 20 #include <dlfcn.h> 21 #include <stddef.h> 22 #include <stdint.h> 23 #include <string.h> 24 #include <stdio.h> 25 26 #ifdef WITH_OPENSSL 27 #include <openssl/objects.h> 28 #include <openssl/ec.h> 29 #endif /* WITH_OPENSSL */ 30 31 #include "log.h" 32 #include "misc.h" 33 #include "sshbuf.h" 34 #include "sshkey.h" 35 #include "ssherr.h" 36 #include "digest.h" 37 38 #include "ssh-sk.h" 39 #include "sk-api.h" 40 #include "crypto_api.h" 41 42 struct sshsk_provider { 43 char *path; 44 void *dlhandle; 45 46 /* Return the version of the middleware API */ 47 uint32_t (*sk_api_version)(void); 48 49 /* Enroll a U2F key (private key generation) */ 50 int (*sk_enroll)(int alg, const uint8_t *challenge, 51 size_t challenge_len, const char *application, uint8_t flags, 52 const char *pin, struct sk_option **opts, 53 struct sk_enroll_response **enroll_response); 54 55 /* Sign a challenge */ 56 int (*sk_sign)(int alg, const uint8_t *message, size_t message_len, 57 const char *application, 58 const uint8_t *key_handle, size_t key_handle_len, 59 uint8_t flags, const char *pin, struct sk_option **opts, 60 struct sk_sign_response **sign_response); 61 62 /* Enumerate resident keys */ 63 int (*sk_load_resident_keys)(const char *pin, struct sk_option **opts, 64 struct sk_resident_key ***rks, size_t *nrks); 65 }; 66 67 /* Built-in version */ 68 int ssh_sk_enroll(int alg, const uint8_t *challenge, 69 size_t challenge_len, const char *application, uint8_t flags, 70 const char *pin, struct sk_option **opts, 71 struct sk_enroll_response **enroll_response); 72 int ssh_sk_sign(int alg, const uint8_t *message, size_t message_len, 73 const char *application, 74 const uint8_t *key_handle, size_t key_handle_len, 75 uint8_t flags, const char *pin, struct sk_option **opts, 76 struct sk_sign_response **sign_response); 77 int ssh_sk_load_resident_keys(const char *pin, struct sk_option **opts, 78 struct sk_resident_key ***rks, size_t *nrks); 79 80 static void 81 sshsk_free(struct sshsk_provider *p) 82 { 83 if (p == NULL) 84 return; 85 free(p->path); 86 if (p->dlhandle != NULL) 87 dlclose(p->dlhandle); 88 free(p); 89 } 90 91 static struct sshsk_provider * 92 sshsk_open(const char *path) 93 { 94 struct sshsk_provider *ret = NULL; 95 uint32_t version; 96 97 if (path == NULL || *path == '\0') { 98 error("No FIDO SecurityKeyProvider specified"); 99 return NULL; 100 } 101 if ((ret = calloc(1, sizeof(*ret))) == NULL) { 102 error_f("calloc failed"); 103 return NULL; 104 } 105 if ((ret->path = strdup(path)) == NULL) { 106 error_f("strdup failed"); 107 goto fail; 108 } 109 /* Skip the rest if we're using the linked in middleware */ 110 if (strcasecmp(ret->path, "internal") == 0) { 111 ret->sk_enroll = ssh_sk_enroll; 112 ret->sk_sign = ssh_sk_sign; 113 ret->sk_load_resident_keys = ssh_sk_load_resident_keys; 114 return ret; 115 } 116 if ((ret->dlhandle = dlopen(path, RTLD_NOW)) == NULL) { 117 error("Provider \"%s\" dlopen failed: %s", path, dlerror()); 118 goto fail; 119 } 120 if ((ret->sk_api_version = dlsym(ret->dlhandle, 121 "sk_api_version")) == NULL) { 122 error("Provider \"%s\" dlsym(sk_api_version) failed: %s", 123 path, dlerror()); 124 goto fail; 125 } 126 version = ret->sk_api_version(); 127 debug_f("provider %s implements version 0x%08lx", ret->path, 128 (u_long)version); 129 if ((version & SSH_SK_VERSION_MAJOR_MASK) != SSH_SK_VERSION_MAJOR) { 130 error("Provider \"%s\" implements unsupported " 131 "version 0x%08lx (supported: 0x%08lx)", 132 path, (u_long)version, (u_long)SSH_SK_VERSION_MAJOR); 133 goto fail; 134 } 135 if ((ret->sk_enroll = dlsym(ret->dlhandle, "sk_enroll")) == NULL) { 136 error("Provider %s dlsym(sk_enroll) failed: %s", 137 path, dlerror()); 138 goto fail; 139 } 140 if ((ret->sk_sign = dlsym(ret->dlhandle, "sk_sign")) == NULL) { 141 error("Provider \"%s\" dlsym(sk_sign) failed: %s", 142 path, dlerror()); 143 goto fail; 144 } 145 if ((ret->sk_load_resident_keys = dlsym(ret->dlhandle, 146 "sk_load_resident_keys")) == NULL) { 147 error("Provider \"%s\" dlsym(sk_load_resident_keys) " 148 "failed: %s", path, dlerror()); 149 goto fail; 150 } 151 /* success */ 152 return ret; 153 fail: 154 sshsk_free(ret); 155 return NULL; 156 } 157 158 static void 159 sshsk_free_enroll_response(struct sk_enroll_response *r) 160 { 161 if (r == NULL) 162 return; 163 freezero(r->key_handle, r->key_handle_len); 164 freezero(r->public_key, r->public_key_len); 165 freezero(r->signature, r->signature_len); 166 freezero(r->attestation_cert, r->attestation_cert_len); 167 freezero(r->authdata, r->authdata_len); 168 freezero(r, sizeof(*r)); 169 } 170 171 static void 172 sshsk_free_sign_response(struct sk_sign_response *r) 173 { 174 if (r == NULL) 175 return; 176 freezero(r->sig_r, r->sig_r_len); 177 freezero(r->sig_s, r->sig_s_len); 178 freezero(r, sizeof(*r)); 179 } 180 181 #ifdef WITH_OPENSSL 182 /* Assemble key from response */ 183 static int 184 sshsk_ecdsa_assemble(struct sk_enroll_response *resp, struct sshkey **keyp) 185 { 186 struct sshkey *key = NULL; 187 struct sshbuf *b = NULL; 188 EC_POINT *q = NULL; 189 int r; 190 191 *keyp = NULL; 192 if ((key = sshkey_new(KEY_ECDSA_SK)) == NULL) { 193 error_f("sshkey_new failed"); 194 r = SSH_ERR_ALLOC_FAIL; 195 goto out; 196 } 197 key->ecdsa_nid = NID_X9_62_prime256v1; 198 if ((key->ecdsa = EC_KEY_new_by_curve_name(key->ecdsa_nid)) == NULL || 199 (q = EC_POINT_new(EC_KEY_get0_group(key->ecdsa))) == NULL || 200 (b = sshbuf_new()) == NULL) { 201 error_f("allocation failed"); 202 r = SSH_ERR_ALLOC_FAIL; 203 goto out; 204 } 205 if ((r = sshbuf_put_string(b, 206 resp->public_key, resp->public_key_len)) != 0) { 207 error_fr(r, "sshbuf_put_string"); 208 goto out; 209 } 210 if ((r = sshbuf_get_ec(b, q, EC_KEY_get0_group(key->ecdsa))) != 0) { 211 error_fr(r, "parse"); 212 r = SSH_ERR_INVALID_FORMAT; 213 goto out; 214 } 215 if (sshkey_ec_validate_public(EC_KEY_get0_group(key->ecdsa), q) != 0) { 216 error("Authenticator returned invalid ECDSA key"); 217 r = SSH_ERR_KEY_INVALID_EC_VALUE; 218 goto out; 219 } 220 if (EC_KEY_set_public_key(key->ecdsa, q) != 1) { 221 /* XXX assume it is a allocation error */ 222 error_f("allocation failed"); 223 r = SSH_ERR_ALLOC_FAIL; 224 goto out; 225 } 226 /* success */ 227 *keyp = key; 228 key = NULL; /* transferred */ 229 r = 0; 230 out: 231 EC_POINT_free(q); 232 sshkey_free(key); 233 sshbuf_free(b); 234 return r; 235 } 236 #endif /* WITH_OPENSSL */ 237 238 static int 239 sshsk_ed25519_assemble(struct sk_enroll_response *resp, struct sshkey **keyp) 240 { 241 struct sshkey *key = NULL; 242 int r; 243 244 *keyp = NULL; 245 if (resp->public_key_len != ED25519_PK_SZ) { 246 error_f("invalid size: %zu", resp->public_key_len); 247 r = SSH_ERR_INVALID_FORMAT; 248 goto out; 249 } 250 if ((key = sshkey_new(KEY_ED25519_SK)) == NULL) { 251 error_f("sshkey_new failed"); 252 r = SSH_ERR_ALLOC_FAIL; 253 goto out; 254 } 255 if ((key->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL) { 256 error_f("malloc failed"); 257 r = SSH_ERR_ALLOC_FAIL; 258 goto out; 259 } 260 memcpy(key->ed25519_pk, resp->public_key, ED25519_PK_SZ); 261 /* success */ 262 *keyp = key; 263 key = NULL; /* transferred */ 264 r = 0; 265 out: 266 sshkey_free(key); 267 return r; 268 } 269 270 static int 271 sshsk_key_from_response(int alg, const char *application, uint8_t flags, 272 struct sk_enroll_response *resp, struct sshkey **keyp) 273 { 274 struct sshkey *key = NULL; 275 int r = SSH_ERR_INTERNAL_ERROR; 276 277 *keyp = NULL; 278 279 /* Check response validity */ 280 if (resp->public_key == NULL || resp->key_handle == NULL) { 281 error_f("sk_enroll response invalid"); 282 r = SSH_ERR_INVALID_FORMAT; 283 goto out; 284 } 285 switch (alg) { 286 #ifdef WITH_OPENSSL 287 case SSH_SK_ECDSA: 288 if ((r = sshsk_ecdsa_assemble(resp, &key)) != 0) 289 goto out; 290 break; 291 #endif /* WITH_OPENSSL */ 292 case SSH_SK_ED25519: 293 if ((r = sshsk_ed25519_assemble(resp, &key)) != 0) 294 goto out; 295 break; 296 default: 297 error_f("unsupported algorithm %d", alg); 298 r = SSH_ERR_INVALID_ARGUMENT; 299 goto out; 300 } 301 key->sk_flags = flags; 302 if ((key->sk_key_handle = sshbuf_new()) == NULL || 303 (key->sk_reserved = sshbuf_new()) == NULL) { 304 error_f("allocation failed"); 305 r = SSH_ERR_ALLOC_FAIL; 306 goto out; 307 } 308 if ((key->sk_application = strdup(application)) == NULL) { 309 error_f("strdup application failed"); 310 r = SSH_ERR_ALLOC_FAIL; 311 goto out; 312 } 313 if ((r = sshbuf_put(key->sk_key_handle, resp->key_handle, 314 resp->key_handle_len)) != 0) { 315 error_fr(r, "put key handle"); 316 goto out; 317 } 318 /* success */ 319 r = 0; 320 *keyp = key; 321 key = NULL; 322 out: 323 sshkey_free(key); 324 return r; 325 } 326 327 static int 328 skerr_to_ssherr(int skerr) 329 { 330 switch (skerr) { 331 case SSH_SK_ERR_UNSUPPORTED: 332 return SSH_ERR_FEATURE_UNSUPPORTED; 333 case SSH_SK_ERR_PIN_REQUIRED: 334 return SSH_ERR_KEY_WRONG_PASSPHRASE; 335 case SSH_SK_ERR_DEVICE_NOT_FOUND: 336 return SSH_ERR_DEVICE_NOT_FOUND; 337 case SSH_SK_ERR_CREDENTIAL_EXISTS: 338 return SSH_ERR_KEY_BAD_PERMISSIONS; 339 case SSH_SK_ERR_GENERAL: 340 default: 341 return SSH_ERR_INVALID_FORMAT; 342 } 343 } 344 345 static void 346 sshsk_free_options(struct sk_option **opts) 347 { 348 size_t i; 349 350 if (opts == NULL) 351 return; 352 for (i = 0; opts[i] != NULL; i++) { 353 free(opts[i]->name); 354 free(opts[i]->value); 355 free(opts[i]); 356 } 357 free(opts); 358 } 359 360 static int 361 sshsk_add_option(struct sk_option ***optsp, size_t *noptsp, 362 const char *name, const char *value, uint8_t required) 363 { 364 struct sk_option **opts = *optsp; 365 size_t nopts = *noptsp; 366 367 if ((opts = recallocarray(opts, nopts, nopts + 2, /* extra for NULL */ 368 sizeof(*opts))) == NULL) { 369 error_f("array alloc failed"); 370 return SSH_ERR_ALLOC_FAIL; 371 } 372 *optsp = opts; 373 *noptsp = nopts + 1; 374 if ((opts[nopts] = calloc(1, sizeof(**opts))) == NULL) { 375 error_f("alloc failed"); 376 return SSH_ERR_ALLOC_FAIL; 377 } 378 if ((opts[nopts]->name = strdup(name)) == NULL || 379 (opts[nopts]->value = strdup(value)) == NULL) { 380 error_f("alloc failed"); 381 return SSH_ERR_ALLOC_FAIL; 382 } 383 opts[nopts]->required = required; 384 return 0; 385 } 386 387 static int 388 make_options(const char *device, const char *user_id, 389 struct sk_option ***optsp) 390 { 391 struct sk_option **opts = NULL; 392 size_t nopts = 0; 393 int r, ret = SSH_ERR_INTERNAL_ERROR; 394 395 if (device != NULL && 396 (r = sshsk_add_option(&opts, &nopts, "device", device, 0)) != 0) { 397 ret = r; 398 goto out; 399 } 400 if (user_id != NULL && 401 (r = sshsk_add_option(&opts, &nopts, "user", user_id, 0)) != 0) { 402 ret = r; 403 goto out; 404 } 405 /* success */ 406 *optsp = opts; 407 opts = NULL; 408 nopts = 0; 409 ret = 0; 410 out: 411 sshsk_free_options(opts); 412 return ret; 413 } 414 415 416 static int 417 fill_attestation_blob(const struct sk_enroll_response *resp, 418 struct sshbuf *attest) 419 { 420 int r; 421 422 if (attest == NULL) 423 return 0; /* nothing to do */ 424 if ((r = sshbuf_put_cstring(attest, "ssh-sk-attest-v01")) != 0 || 425 (r = sshbuf_put_string(attest, 426 resp->attestation_cert, resp->attestation_cert_len)) != 0 || 427 (r = sshbuf_put_string(attest, 428 resp->signature, resp->signature_len)) != 0 || 429 (r = sshbuf_put_string(attest, 430 resp->authdata, resp->authdata_len)) != 0 || 431 (r = sshbuf_put_u32(attest, 0)) != 0 || /* resvd flags */ 432 (r = sshbuf_put_string(attest, NULL, 0)) != 0 /* resvd */) { 433 error_fr(r, "compose"); 434 return r; 435 } 436 /* success */ 437 return 0; 438 } 439 440 int 441 sshsk_enroll(int type, const char *provider_path, const char *device, 442 const char *application, const char *userid, uint8_t flags, 443 const char *pin, struct sshbuf *challenge_buf, 444 struct sshkey **keyp, struct sshbuf *attest) 445 { 446 struct sshsk_provider *skp = NULL; 447 struct sshkey *key = NULL; 448 u_char randchall[32]; 449 const u_char *challenge; 450 size_t challenge_len; 451 struct sk_enroll_response *resp = NULL; 452 struct sk_option **opts = NULL; 453 int r = SSH_ERR_INTERNAL_ERROR; 454 int alg; 455 456 debug_f("provider \"%s\", device \"%s\", application \"%s\", " 457 "userid \"%s\", flags 0x%02x, challenge len %zu%s", 458 provider_path, device, application, userid, flags, 459 challenge_buf == NULL ? 0 : sshbuf_len(challenge_buf), 460 (pin != NULL && *pin != '\0') ? " with-pin" : ""); 461 462 *keyp = NULL; 463 if (attest) 464 sshbuf_reset(attest); 465 466 if ((r = make_options(device, userid, &opts)) != 0) 467 goto out; 468 469 switch (type) { 470 #ifdef WITH_OPENSSL 471 case KEY_ECDSA_SK: 472 alg = SSH_SK_ECDSA; 473 break; 474 #endif /* WITH_OPENSSL */ 475 case KEY_ED25519_SK: 476 alg = SSH_SK_ED25519; 477 break; 478 default: 479 error_f("unsupported key type"); 480 r = SSH_ERR_INVALID_ARGUMENT; 481 goto out; 482 } 483 if (provider_path == NULL) { 484 error_f("missing provider"); 485 r = SSH_ERR_INVALID_ARGUMENT; 486 goto out; 487 } 488 if (application == NULL || *application == '\0') { 489 error_f("missing application"); 490 r = SSH_ERR_INVALID_ARGUMENT; 491 goto out; 492 } 493 if (challenge_buf == NULL) { 494 debug_f("using random challenge"); 495 arc4random_buf(randchall, sizeof(randchall)); 496 challenge = randchall; 497 challenge_len = sizeof(randchall); 498 } else if (sshbuf_len(challenge_buf) == 0) { 499 error("Missing enrollment challenge"); 500 r = SSH_ERR_INVALID_ARGUMENT; 501 goto out; 502 } else { 503 challenge = sshbuf_ptr(challenge_buf); 504 challenge_len = sshbuf_len(challenge_buf); 505 debug3_f("using explicit challenge len=%zd", challenge_len); 506 } 507 if ((skp = sshsk_open(provider_path)) == NULL) { 508 r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */ 509 goto out; 510 } 511 /* XXX validate flags? */ 512 /* enroll key */ 513 if ((r = skp->sk_enroll(alg, challenge, challenge_len, application, 514 flags, pin, opts, &resp)) != 0) { 515 debug_f("provider \"%s\" failure %d", provider_path, r); 516 r = skerr_to_ssherr(r); 517 goto out; 518 } 519 520 if ((r = sshsk_key_from_response(alg, application, resp->flags, 521 resp, &key)) != 0) 522 goto out; 523 524 /* Optionally fill in the attestation information */ 525 if ((r = fill_attestation_blob(resp, attest)) != 0) 526 goto out; 527 528 /* success */ 529 *keyp = key; 530 key = NULL; /* transferred */ 531 r = 0; 532 out: 533 sshsk_free_options(opts); 534 sshsk_free(skp); 535 sshkey_free(key); 536 sshsk_free_enroll_response(resp); 537 explicit_bzero(randchall, sizeof(randchall)); 538 return r; 539 } 540 541 #ifdef WITH_OPENSSL 542 static int 543 sshsk_ecdsa_sig(struct sk_sign_response *resp, struct sshbuf *sig) 544 { 545 struct sshbuf *inner_sig = NULL; 546 int r = SSH_ERR_INTERNAL_ERROR; 547 548 /* Check response validity */ 549 if (resp->sig_r == NULL || resp->sig_s == NULL) { 550 error_f("sk_sign response invalid"); 551 r = SSH_ERR_INVALID_FORMAT; 552 goto out; 553 } 554 if ((inner_sig = sshbuf_new()) == NULL) { 555 r = SSH_ERR_ALLOC_FAIL; 556 goto out; 557 } 558 /* Prepare and append inner signature object */ 559 if ((r = sshbuf_put_bignum2_bytes(inner_sig, 560 resp->sig_r, resp->sig_r_len)) != 0 || 561 (r = sshbuf_put_bignum2_bytes(inner_sig, 562 resp->sig_s, resp->sig_s_len)) != 0) { 563 error_fr(r, "compose inner"); 564 goto out; 565 } 566 if ((r = sshbuf_put_stringb(sig, inner_sig)) != 0 || 567 (r = sshbuf_put_u8(sig, resp->flags)) != 0 || 568 (r = sshbuf_put_u32(sig, resp->counter)) != 0) { 569 error_fr(r, "compose"); 570 goto out; 571 } 572 #ifdef DEBUG_SK 573 fprintf(stderr, "%s: sig_r:\n", __func__); 574 sshbuf_dump_data(resp->sig_r, resp->sig_r_len, stderr); 575 fprintf(stderr, "%s: sig_s:\n", __func__); 576 sshbuf_dump_data(resp->sig_s, resp->sig_s_len, stderr); 577 fprintf(stderr, "%s: inner:\n", __func__); 578 sshbuf_dump(inner_sig, stderr); 579 #endif 580 r = 0; 581 out: 582 sshbuf_free(inner_sig); 583 return r; 584 } 585 #endif /* WITH_OPENSSL */ 586 587 static int 588 sshsk_ed25519_sig(struct sk_sign_response *resp, struct sshbuf *sig) 589 { 590 int r = SSH_ERR_INTERNAL_ERROR; 591 592 /* Check response validity */ 593 if (resp->sig_r == NULL) { 594 error_f("sk_sign response invalid"); 595 r = SSH_ERR_INVALID_FORMAT; 596 goto out; 597 } 598 if ((r = sshbuf_put_string(sig, 599 resp->sig_r, resp->sig_r_len)) != 0 || 600 (r = sshbuf_put_u8(sig, resp->flags)) != 0 || 601 (r = sshbuf_put_u32(sig, resp->counter)) != 0) { 602 error_fr(r, "compose"); 603 goto out; 604 } 605 #ifdef DEBUG_SK 606 fprintf(stderr, "%s: sig_r:\n", __func__); 607 sshbuf_dump_data(resp->sig_r, resp->sig_r_len, stderr); 608 #endif 609 r = 0; 610 out: 611 return r; 612 } 613 614 int 615 sshsk_sign(const char *provider_path, struct sshkey *key, 616 u_char **sigp, size_t *lenp, const u_char *data, size_t datalen, 617 u_int compat, const char *pin) 618 { 619 struct sshsk_provider *skp = NULL; 620 int r = SSH_ERR_INTERNAL_ERROR; 621 int type, alg; 622 struct sk_sign_response *resp = NULL; 623 struct sshbuf *inner_sig = NULL, *sig = NULL; 624 struct sk_option **opts = NULL; 625 626 debug_f("provider \"%s\", key %s, flags 0x%02x%s", 627 provider_path, sshkey_type(key), key->sk_flags, 628 (pin != NULL && *pin != '\0') ? " with-pin" : ""); 629 630 if (sigp != NULL) 631 *sigp = NULL; 632 if (lenp != NULL) 633 *lenp = 0; 634 type = sshkey_type_plain(key->type); 635 switch (type) { 636 #ifdef WITH_OPENSSL 637 case KEY_ECDSA_SK: 638 alg = SSH_SK_ECDSA; 639 break; 640 #endif /* WITH_OPENSSL */ 641 case KEY_ED25519_SK: 642 alg = SSH_SK_ED25519; 643 break; 644 default: 645 return SSH_ERR_INVALID_ARGUMENT; 646 } 647 if (provider_path == NULL || 648 key->sk_key_handle == NULL || 649 key->sk_application == NULL || *key->sk_application == '\0') { 650 r = SSH_ERR_INVALID_ARGUMENT; 651 goto out; 652 } 653 if ((skp = sshsk_open(provider_path)) == NULL) { 654 r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */ 655 goto out; 656 } 657 #ifdef DEBUG_SK 658 fprintf(stderr, "%s: sk_flags = 0x%02x, sk_application = \"%s\"\n", 659 __func__, key->sk_flags, key->sk_application); 660 fprintf(stderr, "%s: sk_key_handle:\n", __func__); 661 sshbuf_dump(key->sk_key_handle, stderr); 662 #endif 663 if ((r = skp->sk_sign(alg, data, datalen, key->sk_application, 664 sshbuf_ptr(key->sk_key_handle), sshbuf_len(key->sk_key_handle), 665 key->sk_flags, pin, opts, &resp)) != 0) { 666 debug_f("sk_sign failed with code %d", r); 667 r = skerr_to_ssherr(r); 668 goto out; 669 } 670 /* Assemble signature */ 671 if ((sig = sshbuf_new()) == NULL) { 672 r = SSH_ERR_ALLOC_FAIL; 673 goto out; 674 } 675 if ((r = sshbuf_put_cstring(sig, sshkey_ssh_name_plain(key))) != 0) { 676 error_fr(r, "compose outer"); 677 goto out; 678 } 679 switch (type) { 680 #ifdef WITH_OPENSSL 681 case KEY_ECDSA_SK: 682 if ((r = sshsk_ecdsa_sig(resp, sig)) != 0) 683 goto out; 684 break; 685 #endif /* WITH_OPENSSL */ 686 case KEY_ED25519_SK: 687 if ((r = sshsk_ed25519_sig(resp, sig)) != 0) 688 goto out; 689 break; 690 } 691 #ifdef DEBUG_SK 692 fprintf(stderr, "%s: sig_flags = 0x%02x, sig_counter = %u\n", 693 __func__, resp->flags, resp->counter); 694 fprintf(stderr, "%s: data to sign:\n", __func__); 695 sshbuf_dump_data(data, datalen, stderr); 696 fprintf(stderr, "%s: sigbuf:\n", __func__); 697 sshbuf_dump(sig, stderr); 698 #endif 699 if (sigp != NULL) { 700 if ((*sigp = malloc(sshbuf_len(sig))) == NULL) { 701 r = SSH_ERR_ALLOC_FAIL; 702 goto out; 703 } 704 memcpy(*sigp, sshbuf_ptr(sig), sshbuf_len(sig)); 705 } 706 if (lenp != NULL) 707 *lenp = sshbuf_len(sig); 708 /* success */ 709 r = 0; 710 out: 711 sshsk_free_options(opts); 712 sshsk_free(skp); 713 sshsk_free_sign_response(resp); 714 sshbuf_free(sig); 715 sshbuf_free(inner_sig); 716 return r; 717 } 718 719 static void 720 sshsk_free_sk_resident_keys(struct sk_resident_key **rks, size_t nrks) 721 { 722 size_t i; 723 724 if (nrks == 0 || rks == NULL) 725 return; 726 for (i = 0; i < nrks; i++) { 727 free(rks[i]->application); 728 freezero(rks[i]->user_id, rks[i]->user_id_len); 729 freezero(rks[i]->key.key_handle, rks[i]->key.key_handle_len); 730 freezero(rks[i]->key.public_key, rks[i]->key.public_key_len); 731 freezero(rks[i]->key.signature, rks[i]->key.signature_len); 732 freezero(rks[i]->key.attestation_cert, 733 rks[i]->key.attestation_cert_len); 734 freezero(rks[i], sizeof(**rks)); 735 } 736 free(rks); 737 } 738 739 static void 740 sshsk_free_resident_key(struct sshsk_resident_key *srk) 741 { 742 if (srk == NULL) 743 return; 744 sshkey_free(srk->key); 745 freezero(srk->user_id, srk->user_id_len); 746 free(srk); 747 } 748 749 750 void 751 sshsk_free_resident_keys(struct sshsk_resident_key **srks, size_t nsrks) 752 { 753 size_t i; 754 755 if (srks == NULL || nsrks == 0) 756 return; 757 758 for (i = 0; i < nsrks; i++) 759 sshsk_free_resident_key(srks[i]); 760 free(srks); 761 } 762 763 int 764 sshsk_load_resident(const char *provider_path, const char *device, 765 const char *pin, u_int flags, struct sshsk_resident_key ***srksp, 766 size_t *nsrksp) 767 { 768 struct sshsk_provider *skp = NULL; 769 int r = SSH_ERR_INTERNAL_ERROR; 770 struct sk_resident_key **rks = NULL; 771 size_t i, nrks = 0, nsrks = 0; 772 struct sshkey *key = NULL; 773 struct sshsk_resident_key *srk = NULL, **srks = NULL, **tmp; 774 uint8_t sk_flags; 775 struct sk_option **opts = NULL; 776 777 debug_f("provider \"%s\"%s", provider_path, 778 (pin != NULL && *pin != '\0') ? ", have-pin": ""); 779 780 if (srksp == NULL || nsrksp == NULL) 781 return SSH_ERR_INVALID_ARGUMENT; 782 *srksp = NULL; 783 *nsrksp = 0; 784 785 if ((r = make_options(device, NULL, &opts)) != 0) 786 goto out; 787 if ((skp = sshsk_open(provider_path)) == NULL) { 788 r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */ 789 goto out; 790 } 791 if ((r = skp->sk_load_resident_keys(pin, opts, &rks, &nrks)) != 0) { 792 error("Provider \"%s\" returned failure %d", provider_path, r); 793 r = skerr_to_ssherr(r); 794 goto out; 795 } 796 for (i = 0; i < nrks; i++) { 797 debug3_f("rk %zu: slot %zu, alg %d, app \"%s\", uidlen %zu", 798 i, rks[i]->slot, rks[i]->alg, rks[i]->application, 799 rks[i]->user_id_len); 800 /* XXX need better filter here */ 801 if (strncmp(rks[i]->application, "ssh:", 4) != 0) 802 continue; 803 switch (rks[i]->alg) { 804 case SSH_SK_ECDSA: 805 case SSH_SK_ED25519: 806 break; 807 default: 808 continue; 809 } 810 sk_flags = SSH_SK_USER_PRESENCE_REQD|SSH_SK_RESIDENT_KEY; 811 if ((rks[i]->flags & SSH_SK_USER_VERIFICATION_REQD)) 812 sk_flags |= SSH_SK_USER_VERIFICATION_REQD; 813 if ((r = sshsk_key_from_response(rks[i]->alg, 814 rks[i]->application, sk_flags, &rks[i]->key, &key)) != 0) 815 goto out; 816 if ((srk = calloc(1, sizeof(*srk))) == NULL) { 817 error_f("calloc failed"); 818 r = SSH_ERR_ALLOC_FAIL; 819 goto out; 820 } 821 srk->key = key; 822 key = NULL; /* transferred */ 823 if ((srk->user_id = calloc(1, rks[i]->user_id_len)) == NULL) { 824 error_f("calloc failed"); 825 r = SSH_ERR_ALLOC_FAIL; 826 goto out; 827 } 828 memcpy(srk->user_id, rks[i]->user_id, rks[i]->user_id_len); 829 srk->user_id_len = rks[i]->user_id_len; 830 if ((tmp = recallocarray(srks, nsrks, nsrks + 1, 831 sizeof(*tmp))) == NULL) { 832 error_f("recallocarray failed"); 833 r = SSH_ERR_ALLOC_FAIL; 834 goto out; 835 } 836 srks = tmp; 837 srks[nsrks++] = srk; 838 srk = NULL; 839 /* XXX synthesise comment */ 840 } 841 /* success */ 842 *srksp = srks; 843 *nsrksp = nsrks; 844 srks = NULL; 845 nsrks = 0; 846 r = 0; 847 out: 848 sshsk_free_options(opts); 849 sshsk_free(skp); 850 sshsk_free_sk_resident_keys(rks, nrks); 851 sshkey_free(key); 852 sshsk_free_resident_key(srk); 853 sshsk_free_resident_keys(srks, nsrks); 854 return r; 855 } 856 857
Indexes created Mon Mar 16 00:23:04 UTC 2026