ssh-sk.c revision 1.1.1.5
1 /* $OpenBSD: ssh-sk.c,v 1.38 2022/01/14 03:35:10 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_GENERAL: 338 default: 339 return SSH_ERR_INVALID_FORMAT; 340 } 341 } 342 343 static void 344 sshsk_free_options(struct sk_option **opts) 345 { 346 size_t i; 347 348 if (opts == NULL) 349 return; 350 for (i = 0; opts[i] != NULL; i++) { 351 free(opts[i]->name); 352 free(opts[i]->value); 353 free(opts[i]); 354 } 355 free(opts); 356 } 357 358 static int 359 sshsk_add_option(struct sk_option ***optsp, size_t *noptsp, 360 const char *name, const char *value, uint8_t required) 361 { 362 struct sk_option **opts = *optsp; 363 size_t nopts = *noptsp; 364 365 if ((opts = recallocarray(opts, nopts, nopts + 2, /* extra for NULL */ 366 sizeof(*opts))) == NULL) { 367 error_f("array alloc failed"); 368 return SSH_ERR_ALLOC_FAIL; 369 } 370 *optsp = opts; 371 *noptsp = nopts + 1; 372 if ((opts[nopts] = calloc(1, sizeof(**opts))) == NULL) { 373 error_f("alloc failed"); 374 return SSH_ERR_ALLOC_FAIL; 375 } 376 if ((opts[nopts]->name = strdup(name)) == NULL || 377 (opts[nopts]->value = strdup(value)) == NULL) { 378 error_f("alloc failed"); 379 return SSH_ERR_ALLOC_FAIL; 380 } 381 opts[nopts]->required = required; 382 return 0; 383 } 384 385 static int 386 make_options(const char *device, const char *user_id, 387 struct sk_option ***optsp) 388 { 389 struct sk_option **opts = NULL; 390 size_t nopts = 0; 391 int r, ret = SSH_ERR_INTERNAL_ERROR; 392 393 if (device != NULL && 394 (r = sshsk_add_option(&opts, &nopts, "device", device, 0)) != 0) { 395 ret = r; 396 goto out; 397 } 398 if (user_id != NULL && 399 (r = sshsk_add_option(&opts, &nopts, "user", user_id, 0)) != 0) { 400 ret = r; 401 goto out; 402 } 403 /* success */ 404 *optsp = opts; 405 opts = NULL; 406 nopts = 0; 407 ret = 0; 408 out: 409 sshsk_free_options(opts); 410 return ret; 411 } 412 413 414 static int 415 fill_attestation_blob(const struct sk_enroll_response *resp, 416 struct sshbuf *attest) 417 { 418 int r; 419 420 if (attest == NULL) 421 return 0; /* nothing to do */ 422 if ((r = sshbuf_put_cstring(attest, "ssh-sk-attest-v01")) != 0 || 423 (r = sshbuf_put_string(attest, 424 resp->attestation_cert, resp->attestation_cert_len)) != 0 || 425 (r = sshbuf_put_string(attest, 426 resp->signature, resp->signature_len)) != 0 || 427 (r = sshbuf_put_string(attest, 428 resp->authdata, resp->authdata_len)) != 0 || 429 (r = sshbuf_put_u32(attest, 0)) != 0 || /* resvd flags */ 430 (r = sshbuf_put_string(attest, NULL, 0)) != 0 /* resvd */) { 431 error_fr(r, "compose"); 432 return r; 433 } 434 /* success */ 435 return 0; 436 } 437 438 int 439 sshsk_enroll(int type, const char *provider_path, const char *device, 440 const char *application, const char *userid, uint8_t flags, 441 const char *pin, struct sshbuf *challenge_buf, 442 struct sshkey **keyp, struct sshbuf *attest) 443 { 444 struct sshsk_provider *skp = NULL; 445 struct sshkey *key = NULL; 446 u_char randchall[32]; 447 const u_char *challenge; 448 size_t challenge_len; 449 struct sk_enroll_response *resp = NULL; 450 struct sk_option **opts = NULL; 451 int r = SSH_ERR_INTERNAL_ERROR; 452 int alg; 453 454 debug_f("provider \"%s\", device \"%s\", application \"%s\", " 455 "userid \"%s\", flags 0x%02x, challenge len %zu%s", 456 provider_path, device, application, userid, flags, 457 challenge_buf == NULL ? 0 : sshbuf_len(challenge_buf), 458 (pin != NULL && *pin != '\0') ? " with-pin" : ""); 459 460 *keyp = NULL; 461 if (attest) 462 sshbuf_reset(attest); 463 464 if ((r = make_options(device, userid, &opts)) != 0) 465 goto out; 466 467 switch (type) { 468 #ifdef WITH_OPENSSL 469 case KEY_ECDSA_SK: 470 alg = SSH_SK_ECDSA; 471 break; 472 #endif /* WITH_OPENSSL */ 473 case KEY_ED25519_SK: 474 alg = SSH_SK_ED25519; 475 break; 476 default: 477 error_f("unsupported key type"); 478 r = SSH_ERR_INVALID_ARGUMENT; 479 goto out; 480 } 481 if (provider_path == NULL) { 482 error_f("missing provider"); 483 r = SSH_ERR_INVALID_ARGUMENT; 484 goto out; 485 } 486 if (application == NULL || *application == '\0') { 487 error_f("missing application"); 488 r = SSH_ERR_INVALID_ARGUMENT; 489 goto out; 490 } 491 if (challenge_buf == NULL) { 492 debug_f("using random challenge"); 493 arc4random_buf(randchall, sizeof(randchall)); 494 challenge = randchall; 495 challenge_len = sizeof(randchall); 496 } else if (sshbuf_len(challenge_buf) == 0) { 497 error("Missing enrollment challenge"); 498 r = SSH_ERR_INVALID_ARGUMENT; 499 goto out; 500 } else { 501 challenge = sshbuf_ptr(challenge_buf); 502 challenge_len = sshbuf_len(challenge_buf); 503 debug3_f("using explicit challenge len=%zd", challenge_len); 504 } 505 if ((skp = sshsk_open(provider_path)) == NULL) { 506 r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */ 507 goto out; 508 } 509 /* XXX validate flags? */ 510 /* enroll key */ 511 if ((r = skp->sk_enroll(alg, challenge, challenge_len, application, 512 flags, pin, opts, &resp)) != 0) { 513 debug_f("provider \"%s\" failure %d", provider_path, r); 514 r = skerr_to_ssherr(r); 515 goto out; 516 } 517 518 if ((r = sshsk_key_from_response(alg, application, resp->flags, 519 resp, &key)) != 0) 520 goto out; 521 522 /* Optionally fill in the attestation information */ 523 if ((r = fill_attestation_blob(resp, attest)) != 0) 524 goto out; 525 526 /* success */ 527 *keyp = key; 528 key = NULL; /* transferred */ 529 r = 0; 530 out: 531 sshsk_free_options(opts); 532 sshsk_free(skp); 533 sshkey_free(key); 534 sshsk_free_enroll_response(resp); 535 explicit_bzero(randchall, sizeof(randchall)); 536 return r; 537 } 538 539 #ifdef WITH_OPENSSL 540 static int 541 sshsk_ecdsa_sig(struct sk_sign_response *resp, struct sshbuf *sig) 542 { 543 struct sshbuf *inner_sig = NULL; 544 int r = SSH_ERR_INTERNAL_ERROR; 545 546 /* Check response validity */ 547 if (resp->sig_r == NULL || resp->sig_s == NULL) { 548 error_f("sk_sign response invalid"); 549 r = SSH_ERR_INVALID_FORMAT; 550 goto out; 551 } 552 if ((inner_sig = sshbuf_new()) == NULL) { 553 r = SSH_ERR_ALLOC_FAIL; 554 goto out; 555 } 556 /* Prepare and append inner signature object */ 557 if ((r = sshbuf_put_bignum2_bytes(inner_sig, 558 resp->sig_r, resp->sig_r_len)) != 0 || 559 (r = sshbuf_put_bignum2_bytes(inner_sig, 560 resp->sig_s, resp->sig_s_len)) != 0) { 561 error_fr(r, "compose inner"); 562 goto out; 563 } 564 if ((r = sshbuf_put_stringb(sig, inner_sig)) != 0 || 565 (r = sshbuf_put_u8(sig, resp->flags)) != 0 || 566 (r = sshbuf_put_u32(sig, resp->counter)) != 0) { 567 error_fr(r, "compose"); 568 goto out; 569 } 570 #ifdef DEBUG_SK 571 fprintf(stderr, "%s: sig_r:\n", __func__); 572 sshbuf_dump_data(resp->sig_r, resp->sig_r_len, stderr); 573 fprintf(stderr, "%s: sig_s:\n", __func__); 574 sshbuf_dump_data(resp->sig_s, resp->sig_s_len, stderr); 575 fprintf(stderr, "%s: inner:\n", __func__); 576 sshbuf_dump(inner_sig, stderr); 577 #endif 578 r = 0; 579 out: 580 sshbuf_free(inner_sig); 581 return r; 582 } 583 #endif /* WITH_OPENSSL */ 584 585 static int 586 sshsk_ed25519_sig(struct sk_sign_response *resp, struct sshbuf *sig) 587 { 588 int r = SSH_ERR_INTERNAL_ERROR; 589 590 /* Check response validity */ 591 if (resp->sig_r == NULL) { 592 error_f("sk_sign response invalid"); 593 r = SSH_ERR_INVALID_FORMAT; 594 goto out; 595 } 596 if ((r = sshbuf_put_string(sig, 597 resp->sig_r, resp->sig_r_len)) != 0 || 598 (r = sshbuf_put_u8(sig, resp->flags)) != 0 || 599 (r = sshbuf_put_u32(sig, resp->counter)) != 0) { 600 error_fr(r, "compose"); 601 goto out; 602 } 603 #ifdef DEBUG_SK 604 fprintf(stderr, "%s: sig_r:\n", __func__); 605 sshbuf_dump_data(resp->sig_r, resp->sig_r_len, stderr); 606 #endif 607 r = 0; 608 out: 609 return r; 610 } 611 612 int 613 sshsk_sign(const char *provider_path, struct sshkey *key, 614 u_char **sigp, size_t *lenp, const u_char *data, size_t datalen, 615 u_int compat, const char *pin) 616 { 617 struct sshsk_provider *skp = NULL; 618 int r = SSH_ERR_INTERNAL_ERROR; 619 int type, alg; 620 struct sk_sign_response *resp = NULL; 621 struct sshbuf *inner_sig = NULL, *sig = NULL; 622 struct sk_option **opts = NULL; 623 624 debug_f("provider \"%s\", key %s, flags 0x%02x%s", 625 provider_path, sshkey_type(key), key->sk_flags, 626 (pin != NULL && *pin != '\0') ? " with-pin" : ""); 627 628 if (sigp != NULL) 629 *sigp = NULL; 630 if (lenp != NULL) 631 *lenp = 0; 632 type = sshkey_type_plain(key->type); 633 switch (type) { 634 #ifdef WITH_OPENSSL 635 case KEY_ECDSA_SK: 636 alg = SSH_SK_ECDSA; 637 break; 638 #endif /* WITH_OPENSSL */ 639 case KEY_ED25519_SK: 640 alg = SSH_SK_ED25519; 641 break; 642 default: 643 return SSH_ERR_INVALID_ARGUMENT; 644 } 645 if (provider_path == NULL || 646 key->sk_key_handle == NULL || 647 key->sk_application == NULL || *key->sk_application == '\0') { 648 r = SSH_ERR_INVALID_ARGUMENT; 649 goto out; 650 } 651 if ((skp = sshsk_open(provider_path)) == NULL) { 652 r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */ 653 goto out; 654 } 655 #ifdef DEBUG_SK 656 fprintf(stderr, "%s: sk_flags = 0x%02x, sk_application = \"%s\"\n", 657 __func__, key->sk_flags, key->sk_application); 658 fprintf(stderr, "%s: sk_key_handle:\n", __func__); 659 sshbuf_dump(key->sk_key_handle, stderr); 660 #endif 661 if ((r = skp->sk_sign(alg, data, datalen, key->sk_application, 662 sshbuf_ptr(key->sk_key_handle), sshbuf_len(key->sk_key_handle), 663 key->sk_flags, pin, opts, &resp)) != 0) { 664 debug_f("sk_sign failed with code %d", r); 665 r = skerr_to_ssherr(r); 666 goto out; 667 } 668 /* Assemble signature */ 669 if ((sig = sshbuf_new()) == NULL) { 670 r = SSH_ERR_ALLOC_FAIL; 671 goto out; 672 } 673 if ((r = sshbuf_put_cstring(sig, sshkey_ssh_name_plain(key))) != 0) { 674 error_fr(r, "compose outer"); 675 goto out; 676 } 677 switch (type) { 678 #ifdef WITH_OPENSSL 679 case KEY_ECDSA_SK: 680 if ((r = sshsk_ecdsa_sig(resp, sig)) != 0) 681 goto out; 682 break; 683 #endif /* WITH_OPENSSL */ 684 case KEY_ED25519_SK: 685 if ((r = sshsk_ed25519_sig(resp, sig)) != 0) 686 goto out; 687 break; 688 } 689 #ifdef DEBUG_SK 690 fprintf(stderr, "%s: sig_flags = 0x%02x, sig_counter = %u\n", 691 __func__, resp->flags, resp->counter); 692 fprintf(stderr, "%s: data to sign:\n", __func__); 693 sshbuf_dump_data(data, datalen, stderr); 694 fprintf(stderr, "%s: sigbuf:\n", __func__); 695 sshbuf_dump(sig, stderr); 696 #endif 697 if (sigp != NULL) { 698 if ((*sigp = malloc(sshbuf_len(sig))) == NULL) { 699 r = SSH_ERR_ALLOC_FAIL; 700 goto out; 701 } 702 memcpy(*sigp, sshbuf_ptr(sig), sshbuf_len(sig)); 703 } 704 if (lenp != NULL) 705 *lenp = sshbuf_len(sig); 706 /* success */ 707 r = 0; 708 out: 709 sshsk_free_options(opts); 710 sshsk_free(skp); 711 sshsk_free_sign_response(resp); 712 sshbuf_free(sig); 713 sshbuf_free(inner_sig); 714 return r; 715 } 716 717 static void 718 sshsk_free_sk_resident_keys(struct sk_resident_key **rks, size_t nrks) 719 { 720 size_t i; 721 722 if (nrks == 0 || rks == NULL) 723 return; 724 for (i = 0; i < nrks; i++) { 725 free(rks[i]->application); 726 freezero(rks[i]->user_id, rks[i]->user_id_len); 727 freezero(rks[i]->key.key_handle, rks[i]->key.key_handle_len); 728 freezero(rks[i]->key.public_key, rks[i]->key.public_key_len); 729 freezero(rks[i]->key.signature, rks[i]->key.signature_len); 730 freezero(rks[i]->key.attestation_cert, 731 rks[i]->key.attestation_cert_len); 732 freezero(rks[i], sizeof(**rks)); 733 } 734 free(rks); 735 } 736 737 static void 738 sshsk_free_resident_key(struct sshsk_resident_key *srk) 739 { 740 if (srk == NULL) 741 return; 742 sshkey_free(srk->key); 743 freezero(srk->user_id, srk->user_id_len); 744 free(srk); 745 } 746 747 748 void 749 sshsk_free_resident_keys(struct sshsk_resident_key **srks, size_t nsrks) 750 { 751 size_t i; 752 753 if (srks == NULL || nsrks == 0) 754 return; 755 756 for (i = 0; i < nsrks; i++) 757 sshsk_free_resident_key(srks[i]); 758 free(srks); 759 } 760 761 int 762 sshsk_load_resident(const char *provider_path, const char *device, 763 const char *pin, u_int flags, struct sshsk_resident_key ***srksp, 764 size_t *nsrksp) 765 { 766 struct sshsk_provider *skp = NULL; 767 int r = SSH_ERR_INTERNAL_ERROR; 768 struct sk_resident_key **rks = NULL; 769 size_t i, nrks = 0, nsrks = 0; 770 struct sshkey *key = NULL; 771 struct sshsk_resident_key *srk = NULL, **srks = NULL, **tmp; 772 uint8_t sk_flags; 773 struct sk_option **opts = NULL; 774 775 debug_f("provider \"%s\"%s", provider_path, 776 (pin != NULL && *pin != '\0') ? ", have-pin": ""); 777 778 if (srksp == NULL || nsrksp == NULL) 779 return SSH_ERR_INVALID_ARGUMENT; 780 *srksp = NULL; 781 *nsrksp = 0; 782 783 if ((r = make_options(device, NULL, &opts)) != 0) 784 goto out; 785 if ((skp = sshsk_open(provider_path)) == NULL) { 786 r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */ 787 goto out; 788 } 789 if ((r = skp->sk_load_resident_keys(pin, opts, &rks, &nrks)) != 0) { 790 error("Provider \"%s\" returned failure %d", provider_path, r); 791 r = skerr_to_ssherr(r); 792 goto out; 793 } 794 for (i = 0; i < nrks; i++) { 795 debug3_f("rk %zu: slot %zu, alg %d, app \"%s\", uidlen %zu", 796 i, rks[i]->slot, rks[i]->alg, rks[i]->application, 797 rks[i]->user_id_len); 798 /* XXX need better filter here */ 799 if (strncmp(rks[i]->application, "ssh:", 4) != 0) 800 continue; 801 switch (rks[i]->alg) { 802 case SSH_SK_ECDSA: 803 case SSH_SK_ED25519: 804 break; 805 default: 806 continue; 807 } 808 sk_flags = SSH_SK_USER_PRESENCE_REQD|SSH_SK_RESIDENT_KEY; 809 if ((rks[i]->flags & SSH_SK_USER_VERIFICATION_REQD)) 810 sk_flags |= SSH_SK_USER_VERIFICATION_REQD; 811 if ((r = sshsk_key_from_response(rks[i]->alg, 812 rks[i]->application, sk_flags, &rks[i]->key, &key)) != 0) 813 goto out; 814 if ((srk = calloc(1, sizeof(*srk))) == NULL) { 815 error_f("calloc failed"); 816 r = SSH_ERR_ALLOC_FAIL; 817 goto out; 818 } 819 srk->key = key; 820 key = NULL; /* transferred */ 821 if ((srk->user_id = calloc(1, rks[i]->user_id_len)) == NULL) { 822 error_f("calloc failed"); 823 r = SSH_ERR_ALLOC_FAIL; 824 goto out; 825 } 826 memcpy(srk->user_id, rks[i]->user_id, rks[i]->user_id_len); 827 srk->user_id_len = rks[i]->user_id_len; 828 if ((tmp = recallocarray(srks, nsrks, nsrks + 1, 829 sizeof(*tmp))) == NULL) { 830 error_f("recallocarray failed"); 831 r = SSH_ERR_ALLOC_FAIL; 832 goto out; 833 } 834 srks = tmp; 835 srks[nsrks++] = srk; 836 srk = NULL; 837 /* XXX synthesise comment */ 838 } 839 /* success */ 840 *srksp = srks; 841 *nsrksp = nsrks; 842 srks = NULL; 843 nsrks = 0; 844 r = 0; 845 out: 846 sshsk_free_options(opts); 847 sshsk_free(skp); 848 sshsk_free_sk_resident_keys(rks, nrks); 849 sshkey_free(key); 850 sshsk_free_resident_key(srk); 851 sshsk_free_resident_keys(srks, nsrks); 852 return r; 853 } 854 855
Indexes created Mon Mar 16 00:23:04 UTC 2026