1 /* 2 * Copyright (c) 2012 Damien Miller <djm@mindrot.org> 3 * 4 * Permission to use, copy, modify, and distribute this software for any 5 * purpose with or without fee is hereby granted, provided that the above 6 * copyright notice and this permission notice appear in all copies. 7 * 8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 15 */ 16 17 /* $OpenBSD: krl.c,v 1.42 2018/09/12 01:21:34 djm Exp $ */ 18 19 #include <sys/types.h> 20 #include <sys/tree.h> 21 #include <sys/queue.h> 22 23 #include <errno.h> 24 #include <fcntl.h> 25 #include <limits.h> 26 #include <string.h> 27 #include <time.h> 28 #include <unistd.h> 29 30 #include "sshbuf.h" 31 #include "ssherr.h" 32 #include "sshkey.h" 33 #include "authfile.h" 34 #include "misc.h" 35 #include "log.h" 36 #include "digest.h" 37 #include "bitmap.h" 38 39 #include "krl.h" 40 41 /* #define DEBUG_KRL */ 42 #ifdef DEBUG_KRL 43 # define KRL_DBG(x) debug3 x 44 #else 45 # define KRL_DBG(x) 46 #endif 47 48 /* 49 * Trees of revoked serial numbers, key IDs and keys. This allows 50 * quick searching, querying and producing lists in canonical order. 51 */ 52 53 /* Tree of serial numbers. XXX make smarter: really need a real sparse bitmap */ 54 struct revoked_serial { 55 u_int64_t lo, hi; 56 RB_ENTRY(revoked_serial) tree_entry; 57 }; 58 static int serial_cmp(struct revoked_serial *a, struct revoked_serial *b); 59 RB_HEAD(revoked_serial_tree, revoked_serial); 60 RB_GENERATE_STATIC(revoked_serial_tree, revoked_serial, tree_entry, serial_cmp); 61 62 /* Tree of key IDs */ 63 struct revoked_key_id { 64 char *key_id; 65 RB_ENTRY(revoked_key_id) tree_entry; 66 }; 67 static int key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b); 68 RB_HEAD(revoked_key_id_tree, revoked_key_id); 69 RB_GENERATE_STATIC(revoked_key_id_tree, revoked_key_id, tree_entry, key_id_cmp); 70 71 /* Tree of blobs (used for keys and fingerprints) */ 72 struct revoked_blob { 73 u_char *blob; 74 size_t len; 75 RB_ENTRY(revoked_blob) tree_entry; 76 }; 77 static int blob_cmp(struct revoked_blob *a, struct revoked_blob *b); 78 RB_HEAD(revoked_blob_tree, revoked_blob); 79 RB_GENERATE_STATIC(revoked_blob_tree, revoked_blob, tree_entry, blob_cmp); 80 81 /* Tracks revoked certs for a single CA */ 82 struct revoked_certs { 83 struct sshkey *ca_key; 84 struct revoked_serial_tree revoked_serials; 85 struct revoked_key_id_tree revoked_key_ids; 86 TAILQ_ENTRY(revoked_certs) entry; 87 }; 88 TAILQ_HEAD(revoked_certs_list, revoked_certs); 89 90 struct ssh_krl { 91 u_int64_t krl_version; 92 u_int64_t generated_date; 93 u_int64_t flags; 94 char *comment; 95 struct revoked_blob_tree revoked_keys; 96 struct revoked_blob_tree revoked_sha1s; 97 struct revoked_blob_tree revoked_sha256s; 98 struct revoked_certs_list revoked_certs; 99 }; 100 101 /* Return equal if a and b overlap */ 102 static int 103 serial_cmp(struct revoked_serial *a, struct revoked_serial *b) 104 { 105 if (a->hi >= b->lo && a->lo <= b->hi) 106 return 0; 107 return a->lo < b->lo ? -1 : 1; 108 } 109 110 static int 111 key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b) 112 { 113 return strcmp(a->key_id, b->key_id); 114 } 115 116 static int 117 blob_cmp(struct revoked_blob *a, struct revoked_blob *b) 118 { 119 int r; 120 121 if (a->len != b->len) { 122 if ((r = memcmp(a->blob, b->blob, MINIMUM(a->len, b->len))) != 0) 123 return r; 124 return a->len > b->len ? 1 : -1; 125 } else 126 return memcmp(a->blob, b->blob, a->len); 127 } 128 129 struct ssh_krl * 130 ssh_krl_init(void) 131 { 132 struct ssh_krl *krl; 133 134 if ((krl = calloc(1, sizeof(*krl))) == NULL) 135 return NULL; 136 RB_INIT(&krl->revoked_keys); 137 RB_INIT(&krl->revoked_sha1s); 138 RB_INIT(&krl->revoked_sha256s); 139 TAILQ_INIT(&krl->revoked_certs); 140 return krl; 141 } 142 143 static void 144 revoked_certs_free(struct revoked_certs *rc) 145 { 146 struct revoked_serial *rs, *trs; 147 struct revoked_key_id *rki, *trki; 148 149 RB_FOREACH_SAFE(rs, revoked_serial_tree, &rc->revoked_serials, trs) { 150 RB_REMOVE(revoked_serial_tree, &rc->revoked_serials, rs); 151 free(rs); 152 } 153 RB_FOREACH_SAFE(rki, revoked_key_id_tree, &rc->revoked_key_ids, trki) { 154 RB_REMOVE(revoked_key_id_tree, &rc->revoked_key_ids, rki); 155 free(rki->key_id); 156 free(rki); 157 } 158 sshkey_free(rc->ca_key); 159 } 160 161 void 162 ssh_krl_free(struct ssh_krl *krl) 163 { 164 struct revoked_blob *rb, *trb; 165 struct revoked_certs *rc, *trc; 166 167 if (krl == NULL) 168 return; 169 170 free(krl->comment); 171 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_keys, trb) { 172 RB_REMOVE(revoked_blob_tree, &krl->revoked_keys, rb); 173 free(rb->blob); 174 free(rb); 175 } 176 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha1s, trb) { 177 RB_REMOVE(revoked_blob_tree, &krl->revoked_sha1s, rb); 178 free(rb->blob); 179 free(rb); 180 } 181 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha256s, trb) { 182 RB_REMOVE(revoked_blob_tree, &krl->revoked_sha256s, rb); 183 free(rb->blob); 184 free(rb); 185 } 186 TAILQ_FOREACH_SAFE(rc, &krl->revoked_certs, entry, trc) { 187 TAILQ_REMOVE(&krl->revoked_certs, rc, entry); 188 revoked_certs_free(rc); 189 } 190 } 191 192 void 193 ssh_krl_set_version(struct ssh_krl *krl, u_int64_t version) 194 { 195 krl->krl_version = version; 196 } 197 198 int 199 ssh_krl_set_comment(struct ssh_krl *krl, const char *comment) 200 { 201 free(krl->comment); 202 if ((krl->comment = strdup(comment)) == NULL) 203 return SSH_ERR_ALLOC_FAIL; 204 return 0; 205 } 206 207 /* 208 * Find the revoked_certs struct for a CA key. If allow_create is set then 209 * create a new one in the tree if one did not exist already. 210 */ 211 static int 212 revoked_certs_for_ca_key(struct ssh_krl *krl, const struct sshkey *ca_key, 213 struct revoked_certs **rcp, int allow_create) 214 { 215 struct revoked_certs *rc; 216 int r; 217 218 *rcp = NULL; 219 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { 220 if ((ca_key == NULL && rc->ca_key == NULL) || 221 sshkey_equal(rc->ca_key, ca_key)) { 222 *rcp = rc; 223 return 0; 224 } 225 } 226 if (!allow_create) 227 return 0; 228 /* If this CA doesn't exist in the list then add it now */ 229 if ((rc = calloc(1, sizeof(*rc))) == NULL) 230 return SSH_ERR_ALLOC_FAIL; 231 if (ca_key == NULL) 232 rc->ca_key = NULL; 233 else if ((r = sshkey_from_private(ca_key, &rc->ca_key)) != 0) { 234 free(rc); 235 return r; 236 } 237 RB_INIT(&rc->revoked_serials); 238 RB_INIT(&rc->revoked_key_ids); 239 TAILQ_INSERT_TAIL(&krl->revoked_certs, rc, entry); 240 KRL_DBG(("%s: new CA %s", __func__, 241 ca_key == NULL ? "*" : sshkey_type(ca_key))); 242 *rcp = rc; 243 return 0; 244 } 245 246 static int 247 insert_serial_range(struct revoked_serial_tree *rt, u_int64_t lo, u_int64_t hi) 248 { 249 struct revoked_serial rs, *ers, *crs, *irs; 250 251 KRL_DBG(("%s: insert %llu:%llu", __func__, lo, hi)); 252 memset(&rs, 0, sizeof(rs)); 253 rs.lo = lo; 254 rs.hi = hi; 255 ers = RB_NFIND(revoked_serial_tree, rt, &rs); 256 if (ers == NULL || serial_cmp(ers, &rs) != 0) { 257 /* No entry matches. Just insert */ 258 if ((irs = malloc(sizeof(rs))) == NULL) 259 return SSH_ERR_ALLOC_FAIL; 260 memcpy(irs, &rs, sizeof(*irs)); 261 ers = RB_INSERT(revoked_serial_tree, rt, irs); 262 if (ers != NULL) { 263 KRL_DBG(("%s: bad: ers != NULL", __func__)); 264 /* Shouldn't happen */ 265 free(irs); 266 return SSH_ERR_INTERNAL_ERROR; 267 } 268 ers = irs; 269 } else { 270 KRL_DBG(("%s: overlap found %llu:%llu", __func__, 271 ers->lo, ers->hi)); 272 /* 273 * The inserted entry overlaps an existing one. Grow the 274 * existing entry. 275 */ 276 if (ers->lo > lo) 277 ers->lo = lo; 278 if (ers->hi < hi) 279 ers->hi = hi; 280 } 281 282 /* 283 * The inserted or revised range might overlap or abut adjacent ones; 284 * coalesce as necessary. 285 */ 286 287 /* Check predecessors */ 288 while ((crs = RB_PREV(revoked_serial_tree, rt, ers)) != NULL) { 289 KRL_DBG(("%s: pred %llu:%llu", __func__, crs->lo, crs->hi)); 290 if (ers->lo != 0 && crs->hi < ers->lo - 1) 291 break; 292 /* This entry overlaps. */ 293 if (crs->lo < ers->lo) { 294 ers->lo = crs->lo; 295 KRL_DBG(("%s: pred extend %llu:%llu", __func__, 296 ers->lo, ers->hi)); 297 } 298 RB_REMOVE(revoked_serial_tree, rt, crs); 299 free(crs); 300 } 301 /* Check successors */ 302 while ((crs = RB_NEXT(revoked_serial_tree, rt, ers)) != NULL) { 303 KRL_DBG(("%s: succ %llu:%llu", __func__, crs->lo, crs->hi)); 304 if (ers->hi != (u_int64_t)-1 && crs->lo > ers->hi + 1) 305 break; 306 /* This entry overlaps. */ 307 if (crs->hi > ers->hi) { 308 ers->hi = crs->hi; 309 KRL_DBG(("%s: succ extend %llu:%llu", __func__, 310 ers->lo, ers->hi)); 311 } 312 RB_REMOVE(revoked_serial_tree, rt, crs); 313 free(crs); 314 } 315 KRL_DBG(("%s: done, final %llu:%llu", __func__, ers->lo, ers->hi)); 316 return 0; 317 } 318 319 int 320 ssh_krl_revoke_cert_by_serial(struct ssh_krl *krl, const struct sshkey *ca_key, 321 u_int64_t serial) 322 { 323 return ssh_krl_revoke_cert_by_serial_range(krl, ca_key, serial, serial); 324 } 325 326 int 327 ssh_krl_revoke_cert_by_serial_range(struct ssh_krl *krl, 328 const struct sshkey *ca_key, u_int64_t lo, u_int64_t hi) 329 { 330 struct revoked_certs *rc; 331 int r; 332 333 if (lo > hi || lo == 0) 334 return SSH_ERR_INVALID_ARGUMENT; 335 if ((r = revoked_certs_for_ca_key(krl, ca_key, &rc, 1)) != 0) 336 return r; 337 return insert_serial_range(&rc->revoked_serials, lo, hi); 338 } 339 340 int 341 ssh_krl_revoke_cert_by_key_id(struct ssh_krl *krl, const struct sshkey *ca_key, 342 const char *key_id) 343 { 344 struct revoked_key_id *rki, *erki; 345 struct revoked_certs *rc; 346 int r; 347 348 if ((r = revoked_certs_for_ca_key(krl, ca_key, &rc, 1)) != 0) 349 return r; 350 351 KRL_DBG(("%s: revoke %s", __func__, key_id)); 352 if ((rki = calloc(1, sizeof(*rki))) == NULL || 353 (rki->key_id = strdup(key_id)) == NULL) { 354 free(rki); 355 return SSH_ERR_ALLOC_FAIL; 356 } 357 erki = RB_INSERT(revoked_key_id_tree, &rc->revoked_key_ids, rki); 358 if (erki != NULL) { 359 free(rki->key_id); 360 free(rki); 361 } 362 return 0; 363 } 364 365 /* Convert "key" to a public key blob without any certificate information */ 366 static int 367 plain_key_blob(const struct sshkey *key, u_char **blob, size_t *blen) 368 { 369 struct sshkey *kcopy; 370 int r; 371 372 if ((r = sshkey_from_private(key, &kcopy)) != 0) 373 return r; 374 if (sshkey_is_cert(kcopy)) { 375 if ((r = sshkey_drop_cert(kcopy)) != 0) { 376 sshkey_free(kcopy); 377 return r; 378 } 379 } 380 r = sshkey_to_blob(kcopy, blob, blen); 381 sshkey_free(kcopy); 382 return r; 383 } 384 385 /* Revoke a key blob. Ownership of blob is transferred to the tree */ 386 static int 387 revoke_blob(struct revoked_blob_tree *rbt, u_char *blob, size_t len) 388 { 389 struct revoked_blob *rb, *erb; 390 391 if ((rb = calloc(1, sizeof(*rb))) == NULL) 392 return SSH_ERR_ALLOC_FAIL; 393 rb->blob = blob; 394 rb->len = len; 395 erb = RB_INSERT(revoked_blob_tree, rbt, rb); 396 if (erb != NULL) { 397 free(rb->blob); 398 free(rb); 399 } 400 return 0; 401 } 402 403 int 404 ssh_krl_revoke_key_explicit(struct ssh_krl *krl, const struct sshkey *key) 405 { 406 u_char *blob; 407 size_t len; 408 int r; 409 410 debug3("%s: revoke type %s", __func__, sshkey_type(key)); 411 if ((r = plain_key_blob(key, &blob, &len)) != 0) 412 return r; 413 return revoke_blob(&krl->revoked_keys, blob, len); 414 } 415 416 static int 417 revoke_by_hash(struct revoked_blob_tree *target, const u_char *p, size_t len) 418 { 419 u_char *blob; 420 int r; 421 422 /* need to copy hash, as revoke_blob steals ownership */ 423 if ((blob = malloc(len)) == NULL) 424 return SSH_ERR_SYSTEM_ERROR; 425 memcpy(blob, p, len); 426 if ((r = revoke_blob(target, blob, len)) != 0) { 427 free(blob); 428 return r; 429 } 430 return 0; 431 } 432 433 int 434 ssh_krl_revoke_key_sha1(struct ssh_krl *krl, const u_char *p, size_t len) 435 { 436 debug3("%s: revoke by sha1", __func__); 437 if (len != 20) 438 return SSH_ERR_INVALID_FORMAT; 439 return revoke_by_hash(&krl->revoked_sha1s, p, len); 440 } 441 442 int 443 ssh_krl_revoke_key_sha256(struct ssh_krl *krl, const u_char *p, size_t len) 444 { 445 debug3("%s: revoke by sha256", __func__); 446 if (len != 32) 447 return SSH_ERR_INVALID_FORMAT; 448 return revoke_by_hash(&krl->revoked_sha256s, p, len); 449 } 450 451 int 452 ssh_krl_revoke_key(struct ssh_krl *krl, const struct sshkey *key) 453 { 454 /* XXX replace with SHA256? */ 455 if (!sshkey_is_cert(key)) 456 return ssh_krl_revoke_key_explicit(krl, key); 457 458 if (key->cert->serial == 0) { 459 return ssh_krl_revoke_cert_by_key_id(krl, 460 key->cert->signature_key, 461 key->cert->key_id); 462 } else { 463 return ssh_krl_revoke_cert_by_serial(krl, 464 key->cert->signature_key, 465 key->cert->serial); 466 } 467 } 468 469 /* 470 * Select the most compact section type to emit next in a KRL based on 471 * the current section type, the run length of contiguous revoked serial 472 * numbers and the gaps from the last and to the next revoked serial. 473 * Applies a mostly-accurate bit cost model to select the section type 474 * that will minimise the size of the resultant KRL. 475 */ 476 static int 477 choose_next_state(int current_state, u_int64_t contig, int final, 478 u_int64_t last_gap, u_int64_t next_gap, int *force_new_section) 479 { 480 int new_state; 481 u_int64_t cost, cost_list, cost_range, cost_bitmap, cost_bitmap_restart; 482 483 /* 484 * Avoid unsigned overflows. 485 * The limits are high enough to avoid confusing the calculations. 486 */ 487 contig = MINIMUM(contig, 1ULL<<31); 488 last_gap = MINIMUM(last_gap, 1ULL<<31); 489 next_gap = MINIMUM(next_gap, 1ULL<<31); 490 491 /* 492 * Calculate the cost to switch from the current state to candidates. 493 * NB. range sections only ever contain a single range, so their 494 * switching cost is independent of the current_state. 495 */ 496 cost_list = cost_bitmap = cost_bitmap_restart = 0; 497 cost_range = 8; 498 switch (current_state) { 499 case KRL_SECTION_CERT_SERIAL_LIST: 500 cost_bitmap_restart = cost_bitmap = 8 + 64; 501 break; 502 case KRL_SECTION_CERT_SERIAL_BITMAP: 503 cost_list = 8; 504 cost_bitmap_restart = 8 + 64; 505 break; 506 case KRL_SECTION_CERT_SERIAL_RANGE: 507 case 0: 508 cost_bitmap_restart = cost_bitmap = 8 + 64; 509 cost_list = 8; 510 } 511 512 /* Estimate base cost in bits of each section type */ 513 cost_list += 64 * contig + (final ? 0 : 8+64); 514 cost_range += (2 * 64) + (final ? 0 : 8+64); 515 cost_bitmap += last_gap + contig + (final ? 0 : MINIMUM(next_gap, 8+64)); 516 cost_bitmap_restart += contig + (final ? 0 : MINIMUM(next_gap, 8+64)); 517 518 /* Convert to byte costs for actual comparison */ 519 cost_list = (cost_list + 7) / 8; 520 cost_bitmap = (cost_bitmap + 7) / 8; 521 cost_bitmap_restart = (cost_bitmap_restart + 7) / 8; 522 cost_range = (cost_range + 7) / 8; 523 524 /* Now pick the best choice */ 525 *force_new_section = 0; 526 new_state = KRL_SECTION_CERT_SERIAL_BITMAP; 527 cost = cost_bitmap; 528 if (cost_range < cost) { 529 new_state = KRL_SECTION_CERT_SERIAL_RANGE; 530 cost = cost_range; 531 } 532 if (cost_list < cost) { 533 new_state = KRL_SECTION_CERT_SERIAL_LIST; 534 cost = cost_list; 535 } 536 if (cost_bitmap_restart < cost) { 537 new_state = KRL_SECTION_CERT_SERIAL_BITMAP; 538 *force_new_section = 1; 539 cost = cost_bitmap_restart; 540 } 541 KRL_DBG(("%s: contig %llu last_gap %llu next_gap %llu final %d, costs:" 542 "list %llu range %llu bitmap %llu new bitmap %llu, " 543 "selected 0x%02x%s", __func__, (long long unsigned)contig, 544 (long long unsigned)last_gap, (long long unsigned)next_gap, final, 545 (long long unsigned)cost_list, (long long unsigned)cost_range, 546 (long long unsigned)cost_bitmap, 547 (long long unsigned)cost_bitmap_restart, new_state, 548 *force_new_section ? " restart" : "")); 549 return new_state; 550 } 551 552 static int 553 put_bitmap(struct sshbuf *buf, struct bitmap *bitmap) 554 { 555 size_t len; 556 u_char *blob; 557 int r; 558 559 len = bitmap_nbytes(bitmap); 560 if ((blob = malloc(len)) == NULL) 561 return SSH_ERR_ALLOC_FAIL; 562 if (bitmap_to_string(bitmap, blob, len) != 0) { 563 free(blob); 564 return SSH_ERR_INTERNAL_ERROR; 565 } 566 r = sshbuf_put_bignum2_bytes(buf, blob, len); 567 free(blob); 568 return r; 569 } 570 571 /* Generate a KRL_SECTION_CERTIFICATES KRL section */ 572 static int 573 revoked_certs_generate(struct revoked_certs *rc, struct sshbuf *buf) 574 { 575 int final, force_new_sect, r = SSH_ERR_INTERNAL_ERROR; 576 u_int64_t i, contig, gap, last = 0, bitmap_start = 0; 577 struct revoked_serial *rs, *nrs; 578 struct revoked_key_id *rki; 579 int next_state, state = 0; 580 struct sshbuf *sect; 581 struct bitmap *bitmap = NULL; 582 583 if ((sect = sshbuf_new()) == NULL) 584 return SSH_ERR_ALLOC_FAIL; 585 586 /* Store the header: optional CA scope key, reserved */ 587 if (rc->ca_key == NULL) { 588 if ((r = sshbuf_put_string(buf, NULL, 0)) != 0) 589 goto out; 590 } else { 591 if ((r = sshkey_puts(rc->ca_key, buf)) != 0) 592 goto out; 593 } 594 if ((r = sshbuf_put_string(buf, NULL, 0)) != 0) 595 goto out; 596 597 /* Store the revoked serials. */ 598 for (rs = RB_MIN(revoked_serial_tree, &rc->revoked_serials); 599 rs != NULL; 600 rs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs)) { 601 KRL_DBG(("%s: serial %llu:%llu state 0x%02x", __func__, 602 (long long unsigned)rs->lo, (long long unsigned)rs->hi, 603 state)); 604 605 /* Check contiguous length and gap to next section (if any) */ 606 nrs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs); 607 final = nrs == NULL; 608 gap = nrs == NULL ? 0 : nrs->lo - rs->hi; 609 contig = 1 + (rs->hi - rs->lo); 610 611 /* Choose next state based on these */ 612 next_state = choose_next_state(state, contig, final, 613 state == 0 ? 0 : rs->lo - last, gap, &force_new_sect); 614 615 /* 616 * If the current section is a range section or has a different 617 * type to the next section, then finish it off now. 618 */ 619 if (state != 0 && (force_new_sect || next_state != state || 620 state == KRL_SECTION_CERT_SERIAL_RANGE)) { 621 KRL_DBG(("%s: finish state 0x%02x", __func__, state)); 622 switch (state) { 623 case KRL_SECTION_CERT_SERIAL_LIST: 624 case KRL_SECTION_CERT_SERIAL_RANGE: 625 break; 626 case KRL_SECTION_CERT_SERIAL_BITMAP: 627 if ((r = put_bitmap(sect, bitmap)) != 0) 628 goto out; 629 bitmap_free(bitmap); 630 bitmap = NULL; 631 break; 632 } 633 if ((r = sshbuf_put_u8(buf, state)) != 0 || 634 (r = sshbuf_put_stringb(buf, sect)) != 0) 635 goto out; 636 sshbuf_reset(sect); 637 } 638 639 /* If we are starting a new section then prepare it now */ 640 if (next_state != state || force_new_sect) { 641 KRL_DBG(("%s: start state 0x%02x", __func__, 642 next_state)); 643 state = next_state; 644 sshbuf_reset(sect); 645 switch (state) { 646 case KRL_SECTION_CERT_SERIAL_LIST: 647 case KRL_SECTION_CERT_SERIAL_RANGE: 648 break; 649 case KRL_SECTION_CERT_SERIAL_BITMAP: 650 if ((bitmap = bitmap_new()) == NULL) { 651 r = SSH_ERR_ALLOC_FAIL; 652 goto out; 653 } 654 bitmap_start = rs->lo; 655 if ((r = sshbuf_put_u64(sect, 656 bitmap_start)) != 0) 657 goto out; 658 break; 659 } 660 } 661 662 /* Perform section-specific processing */ 663 switch (state) { 664 case KRL_SECTION_CERT_SERIAL_LIST: 665 for (i = 0; i < contig; i++) { 666 if ((r = sshbuf_put_u64(sect, rs->lo + i)) != 0) 667 goto out; 668 } 669 break; 670 case KRL_SECTION_CERT_SERIAL_RANGE: 671 if ((r = sshbuf_put_u64(sect, rs->lo)) != 0 || 672 (r = sshbuf_put_u64(sect, rs->hi)) != 0) 673 goto out; 674 break; 675 case KRL_SECTION_CERT_SERIAL_BITMAP: 676 if (rs->lo - bitmap_start > INT_MAX) { 677 error("%s: insane bitmap gap", __func__); 678 goto out; 679 } 680 for (i = 0; i < contig; i++) { 681 if (bitmap_set_bit(bitmap, 682 rs->lo + i - bitmap_start) != 0) { 683 r = SSH_ERR_ALLOC_FAIL; 684 goto out; 685 } 686 } 687 break; 688 } 689 last = rs->hi; 690 } 691 /* Flush the remaining section, if any */ 692 if (state != 0) { 693 KRL_DBG(("%s: serial final flush for state 0x%02x", 694 __func__, state)); 695 switch (state) { 696 case KRL_SECTION_CERT_SERIAL_LIST: 697 case KRL_SECTION_CERT_SERIAL_RANGE: 698 break; 699 case KRL_SECTION_CERT_SERIAL_BITMAP: 700 if ((r = put_bitmap(sect, bitmap)) != 0) 701 goto out; 702 bitmap_free(bitmap); 703 bitmap = NULL; 704 break; 705 } 706 if ((r = sshbuf_put_u8(buf, state)) != 0 || 707 (r = sshbuf_put_stringb(buf, sect)) != 0) 708 goto out; 709 } 710 KRL_DBG(("%s: serial done ", __func__)); 711 712 /* Now output a section for any revocations by key ID */ 713 sshbuf_reset(sect); 714 RB_FOREACH(rki, revoked_key_id_tree, &rc->revoked_key_ids) { 715 KRL_DBG(("%s: key ID %s", __func__, rki->key_id)); 716 if ((r = sshbuf_put_cstring(sect, rki->key_id)) != 0) 717 goto out; 718 } 719 if (sshbuf_len(sect) != 0) { 720 if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERT_KEY_ID)) != 0 || 721 (r = sshbuf_put_stringb(buf, sect)) != 0) 722 goto out; 723 } 724 r = 0; 725 out: 726 bitmap_free(bitmap); 727 sshbuf_free(sect); 728 return r; 729 } 730 731 int 732 ssh_krl_to_blob(struct ssh_krl *krl, struct sshbuf *buf, 733 const struct sshkey **sign_keys, u_int nsign_keys) 734 { 735 int r = SSH_ERR_INTERNAL_ERROR; 736 struct revoked_certs *rc; 737 struct revoked_blob *rb; 738 struct sshbuf *sect; 739 u_char *sblob = NULL; 740 size_t slen, i; 741 742 if (krl->generated_date == 0) 743 krl->generated_date = time(NULL); 744 745 if ((sect = sshbuf_new()) == NULL) 746 return SSH_ERR_ALLOC_FAIL; 747 748 /* Store the header */ 749 if ((r = sshbuf_put(buf, KRL_MAGIC, sizeof(KRL_MAGIC) - 1)) != 0 || 750 (r = sshbuf_put_u32(buf, KRL_FORMAT_VERSION)) != 0 || 751 (r = sshbuf_put_u64(buf, krl->krl_version)) != 0 || 752 (r = sshbuf_put_u64(buf, krl->generated_date)) != 0 || 753 (r = sshbuf_put_u64(buf, krl->flags)) != 0 || 754 (r = sshbuf_put_string(buf, NULL, 0)) != 0 || 755 (r = sshbuf_put_cstring(buf, krl->comment)) != 0) 756 goto out; 757 758 /* Store sections for revoked certificates */ 759 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { 760 sshbuf_reset(sect); 761 if ((r = revoked_certs_generate(rc, sect)) != 0) 762 goto out; 763 if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERTIFICATES)) != 0 || 764 (r = sshbuf_put_stringb(buf, sect)) != 0) 765 goto out; 766 } 767 768 /* Finally, output sections for revocations by public key/hash */ 769 sshbuf_reset(sect); 770 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_keys) { 771 KRL_DBG(("%s: key len %zu ", __func__, rb->len)); 772 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 773 goto out; 774 } 775 if (sshbuf_len(sect) != 0) { 776 if ((r = sshbuf_put_u8(buf, KRL_SECTION_EXPLICIT_KEY)) != 0 || 777 (r = sshbuf_put_stringb(buf, sect)) != 0) 778 goto out; 779 } 780 sshbuf_reset(sect); 781 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha1s) { 782 KRL_DBG(("%s: hash len %zu ", __func__, rb->len)); 783 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 784 goto out; 785 } 786 if (sshbuf_len(sect) != 0) { 787 if ((r = sshbuf_put_u8(buf, 788 KRL_SECTION_FINGERPRINT_SHA1)) != 0 || 789 (r = sshbuf_put_stringb(buf, sect)) != 0) 790 goto out; 791 } 792 sshbuf_reset(sect); 793 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha256s) { 794 KRL_DBG(("%s: hash len %zu ", __func__, rb->len)); 795 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 796 goto out; 797 } 798 if (sshbuf_len(sect) != 0) { 799 if ((r = sshbuf_put_u8(buf, 800 KRL_SECTION_FINGERPRINT_SHA256)) != 0 || 801 (r = sshbuf_put_stringb(buf, sect)) != 0) 802 goto out; 803 } 804 805 for (i = 0; i < nsign_keys; i++) { 806 KRL_DBG(("%s: signature key %s", __func__, 807 sshkey_ssh_name(sign_keys[i]))); 808 if ((r = sshbuf_put_u8(buf, KRL_SECTION_SIGNATURE)) != 0 || 809 (r = sshkey_puts(sign_keys[i], buf)) != 0) 810 goto out; 811 812 if ((r = sshkey_sign(sign_keys[i], &sblob, &slen, 813 sshbuf_ptr(buf), sshbuf_len(buf), NULL, 0)) != 0) 814 goto out; 815 KRL_DBG(("%s: signature sig len %zu", __func__, slen)); 816 if ((r = sshbuf_put_string(buf, sblob, slen)) != 0) 817 goto out; 818 } 819 820 r = 0; 821 out: 822 free(sblob); 823 sshbuf_free(sect); 824 return r; 825 } 826 827 static void 828 format_timestamp(u_int64_t timestamp, char *ts, size_t nts) 829 { 830 time_t t; 831 struct tm *tm; 832 833 t = timestamp; 834 tm = localtime(&t); 835 if (tm == NULL) 836 strlcpy(ts, "<INVALID>", nts); 837 else { 838 *ts = '\0'; 839 strftime(ts, nts, "%Y%m%dT%H%M%S", tm); 840 } 841 } 842 843 static int 844 parse_revoked_certs(struct sshbuf *buf, struct ssh_krl *krl) 845 { 846 int r = SSH_ERR_INTERNAL_ERROR; 847 u_char type; 848 const u_char *blob; 849 size_t blen, nbits; 850 struct sshbuf *subsect = NULL; 851 u_int64_t serial, serial_lo, serial_hi; 852 struct bitmap *bitmap = NULL; 853 char *key_id = NULL; 854 struct sshkey *ca_key = NULL; 855 856 if ((subsect = sshbuf_new()) == NULL) 857 return SSH_ERR_ALLOC_FAIL; 858 859 /* Header: key, reserved */ 860 if ((r = sshbuf_get_string_direct(buf, &blob, &blen)) != 0 || 861 (r = sshbuf_skip_string(buf)) != 0) 862 goto out; 863 if (blen != 0 && (r = sshkey_from_blob(blob, blen, &ca_key)) != 0) 864 goto out; 865 866 while (sshbuf_len(buf) > 0) { 867 sshbuf_free(subsect); 868 subsect = NULL; 869 if ((r = sshbuf_get_u8(buf, &type)) != 0 || 870 (r = sshbuf_froms(buf, &subsect)) != 0) 871 goto out; 872 KRL_DBG(("%s: subsection type 0x%02x", __func__, type)); 873 /* sshbuf_dump(subsect, stderr); */ 874 875 switch (type) { 876 case KRL_SECTION_CERT_SERIAL_LIST: 877 while (sshbuf_len(subsect) > 0) { 878 if ((r = sshbuf_get_u64(subsect, &serial)) != 0) 879 goto out; 880 if ((r = ssh_krl_revoke_cert_by_serial(krl, 881 ca_key, serial)) != 0) 882 goto out; 883 } 884 break; 885 case KRL_SECTION_CERT_SERIAL_RANGE: 886 if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 || 887 (r = sshbuf_get_u64(subsect, &serial_hi)) != 0) 888 goto out; 889 if ((r = ssh_krl_revoke_cert_by_serial_range(krl, 890 ca_key, serial_lo, serial_hi)) != 0) 891 goto out; 892 break; 893 case KRL_SECTION_CERT_SERIAL_BITMAP: 894 if ((bitmap = bitmap_new()) == NULL) { 895 r = SSH_ERR_ALLOC_FAIL; 896 goto out; 897 } 898 if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 || 899 (r = sshbuf_get_bignum2_bytes_direct(subsect, 900 &blob, &blen)) != 0) 901 goto out; 902 if (bitmap_from_string(bitmap, blob, blen) != 0) { 903 r = SSH_ERR_INVALID_FORMAT; 904 goto out; 905 } 906 nbits = bitmap_nbits(bitmap); 907 for (serial = 0; serial < (u_int64_t)nbits; serial++) { 908 if (serial > 0 && serial_lo + serial == 0) { 909 error("%s: bitmap wraps u64", __func__); 910 r = SSH_ERR_INVALID_FORMAT; 911 goto out; 912 } 913 if (!bitmap_test_bit(bitmap, serial)) 914 continue; 915 if ((r = ssh_krl_revoke_cert_by_serial(krl, 916 ca_key, serial_lo + serial)) != 0) 917 goto out; 918 } 919 bitmap_free(bitmap); 920 bitmap = NULL; 921 break; 922 case KRL_SECTION_CERT_KEY_ID: 923 while (sshbuf_len(subsect) > 0) { 924 if ((r = sshbuf_get_cstring(subsect, 925 &key_id, NULL)) != 0) 926 goto out; 927 if ((r = ssh_krl_revoke_cert_by_key_id(krl, 928 ca_key, key_id)) != 0) 929 goto out; 930 free(key_id); 931 key_id = NULL; 932 } 933 break; 934 default: 935 error("Unsupported KRL certificate section %u", type); 936 r = SSH_ERR_INVALID_FORMAT; 937 goto out; 938 } 939 if (sshbuf_len(subsect) > 0) { 940 error("KRL certificate section contains unparsed data"); 941 r = SSH_ERR_INVALID_FORMAT; 942 goto out; 943 } 944 } 945 946 r = 0; 947 out: 948 if (bitmap != NULL) 949 bitmap_free(bitmap); 950 free(key_id); 951 sshkey_free(ca_key); 952 sshbuf_free(subsect); 953 return r; 954 } 955 956 static int 957 blob_section(struct sshbuf *sect, struct revoked_blob_tree *target_tree, 958 size_t expected_len) 959 { 960 u_char *rdata = NULL; 961 size_t rlen = 0; 962 int r; 963 964 while (sshbuf_len(sect) > 0) { 965 if ((r = sshbuf_get_string(sect, &rdata, &rlen)) != 0) 966 return r; 967 if (expected_len != 0 && rlen != expected_len) { 968 error("%s: bad length", __func__); 969 free(rdata); 970 return SSH_ERR_INVALID_FORMAT; 971 } 972 if ((r = revoke_blob(target_tree, rdata, rlen)) != 0) { 973 free(rdata); 974 return r; 975 } 976 } 977 return 0; 978 } 979 980 /* Attempt to parse a KRL, checking its signature (if any) with sign_ca_keys. */ 981 int 982 ssh_krl_from_blob(struct sshbuf *buf, struct ssh_krl **krlp, 983 const struct sshkey **sign_ca_keys, size_t nsign_ca_keys) 984 { 985 struct sshbuf *copy = NULL, *sect = NULL; 986 struct ssh_krl *krl = NULL; 987 char timestamp[64]; 988 int r = SSH_ERR_INTERNAL_ERROR, sig_seen; 989 struct sshkey *key = NULL, **ca_used = NULL, **tmp_ca_used; 990 u_char type; 991 const u_char *blob; 992 size_t i, j, sig_off, sects_off, blen, nca_used; 993 u_int format_version; 994 995 nca_used = 0; 996 *krlp = NULL; 997 if (sshbuf_len(buf) < sizeof(KRL_MAGIC) - 1 || 998 memcmp(sshbuf_ptr(buf), KRL_MAGIC, sizeof(KRL_MAGIC) - 1) != 0) { 999 debug3("%s: not a KRL", __func__); 1000 return SSH_ERR_KRL_BAD_MAGIC; 1001 } 1002 1003 /* Take a copy of the KRL buffer so we can verify its signature later */ 1004 if ((copy = sshbuf_fromb(buf)) == NULL) { 1005 r = SSH_ERR_ALLOC_FAIL; 1006 goto out; 1007 } 1008 if ((r = sshbuf_consume(copy, sizeof(KRL_MAGIC) - 1)) != 0) 1009 goto out; 1010 1011 if ((krl = ssh_krl_init()) == NULL) { 1012 error("%s: alloc failed", __func__); 1013 goto out; 1014 } 1015 1016 if ((r = sshbuf_get_u32(copy, &format_version)) != 0) 1017 goto out; 1018 if (format_version != KRL_FORMAT_VERSION) { 1019 r = SSH_ERR_INVALID_FORMAT; 1020 goto out; 1021 } 1022 if ((r = sshbuf_get_u64(copy, &krl->krl_version)) != 0 || 1023 (r = sshbuf_get_u64(copy, &krl->generated_date)) != 0 || 1024 (r = sshbuf_get_u64(copy, &krl->flags)) != 0 || 1025 (r = sshbuf_skip_string(copy)) != 0 || 1026 (r = sshbuf_get_cstring(copy, &krl->comment, NULL)) != 0) 1027 goto out; 1028 1029 format_timestamp(krl->generated_date, timestamp, sizeof(timestamp)); 1030 debug("KRL version %llu generated at %s%s%s", 1031 (long long unsigned)krl->krl_version, timestamp, 1032 *krl->comment ? ": " : "", krl->comment); 1033 1034 /* 1035 * 1st pass: verify signatures, if any. This is done to avoid 1036 * detailed parsing of data whose provenance is unverified. 1037 */ 1038 sig_seen = 0; 1039 if (sshbuf_len(buf) < sshbuf_len(copy)) { 1040 /* Shouldn't happen */ 1041 r = SSH_ERR_INTERNAL_ERROR; 1042 goto out; 1043 } 1044 sects_off = sshbuf_len(buf) - sshbuf_len(copy); 1045 while (sshbuf_len(copy) > 0) { 1046 if ((r = sshbuf_get_u8(copy, &type)) != 0 || 1047 (r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0) 1048 goto out; 1049 KRL_DBG(("%s: first pass, section 0x%02x", __func__, type)); 1050 if (type != KRL_SECTION_SIGNATURE) { 1051 if (sig_seen) { 1052 error("KRL contains non-signature section " 1053 "after signature"); 1054 r = SSH_ERR_INVALID_FORMAT; 1055 goto out; 1056 } 1057 /* Not interested for now. */ 1058 continue; 1059 } 1060 sig_seen = 1; 1061 /* First string component is the signing key */ 1062 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 1063 r = SSH_ERR_INVALID_FORMAT; 1064 goto out; 1065 } 1066 if (sshbuf_len(buf) < sshbuf_len(copy)) { 1067 /* Shouldn't happen */ 1068 r = SSH_ERR_INTERNAL_ERROR; 1069 goto out; 1070 } 1071 sig_off = sshbuf_len(buf) - sshbuf_len(copy); 1072 /* Second string component is the signature itself */ 1073 if ((r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0) { 1074 r = SSH_ERR_INVALID_FORMAT; 1075 goto out; 1076 } 1077 /* Check signature over entire KRL up to this point */ 1078 if ((r = sshkey_verify(key, blob, blen, 1079 sshbuf_ptr(buf), sig_off, NULL, 0)) != 0) 1080 goto out; 1081 /* Check if this key has already signed this KRL */ 1082 for (i = 0; i < nca_used; i++) { 1083 if (sshkey_equal(ca_used[i], key)) { 1084 error("KRL signed more than once with " 1085 "the same key"); 1086 r = SSH_ERR_INVALID_FORMAT; 1087 goto out; 1088 } 1089 } 1090 /* Record keys used to sign the KRL */ 1091 tmp_ca_used = recallocarray(ca_used, nca_used, nca_used + 1, 1092 sizeof(*ca_used)); 1093 if (tmp_ca_used == NULL) { 1094 r = SSH_ERR_ALLOC_FAIL; 1095 goto out; 1096 } 1097 ca_used = tmp_ca_used; 1098 ca_used[nca_used++] = key; 1099 key = NULL; 1100 } 1101 1102 if (sshbuf_len(copy) != 0) { 1103 /* Shouldn't happen */ 1104 r = SSH_ERR_INTERNAL_ERROR; 1105 goto out; 1106 } 1107 1108 /* 1109 * 2nd pass: parse and load the KRL, skipping the header to the point 1110 * where the section start. 1111 */ 1112 sshbuf_free(copy); 1113 if ((copy = sshbuf_fromb(buf)) == NULL) { 1114 r = SSH_ERR_ALLOC_FAIL; 1115 goto out; 1116 } 1117 if ((r = sshbuf_consume(copy, sects_off)) != 0) 1118 goto out; 1119 while (sshbuf_len(copy) > 0) { 1120 sshbuf_free(sect); 1121 sect = NULL; 1122 if ((r = sshbuf_get_u8(copy, &type)) != 0 || 1123 (r = sshbuf_froms(copy, §)) != 0) 1124 goto out; 1125 KRL_DBG(("%s: second pass, section 0x%02x", __func__, type)); 1126 1127 switch (type) { 1128 case KRL_SECTION_CERTIFICATES: 1129 if ((r = parse_revoked_certs(sect, krl)) != 0) 1130 goto out; 1131 break; 1132 case KRL_SECTION_EXPLICIT_KEY: 1133 if ((r = blob_section(sect, 1134 &krl->revoked_keys, 0)) != 0) 1135 goto out; 1136 break; 1137 case KRL_SECTION_FINGERPRINT_SHA1: 1138 if ((r = blob_section(sect, 1139 &krl->revoked_sha1s, 20)) != 0) 1140 goto out; 1141 break; 1142 case KRL_SECTION_FINGERPRINT_SHA256: 1143 if ((r = blob_section(sect, 1144 &krl->revoked_sha256s, 32)) != 0) 1145 goto out; 1146 break; 1147 case KRL_SECTION_SIGNATURE: 1148 /* Handled above, but still need to stay in synch */ 1149 sshbuf_free(sect); 1150 sect = NULL; 1151 if ((r = sshbuf_skip_string(copy)) != 0) 1152 goto out; 1153 break; 1154 default: 1155 error("Unsupported KRL section %u", type); 1156 r = SSH_ERR_INVALID_FORMAT; 1157 goto out; 1158 } 1159 if (sect != NULL && sshbuf_len(sect) > 0) { 1160 error("KRL section contains unparsed data"); 1161 r = SSH_ERR_INVALID_FORMAT; 1162 goto out; 1163 } 1164 } 1165 1166 /* Check that the key(s) used to sign the KRL weren't revoked */ 1167 sig_seen = 0; 1168 for (i = 0; i < nca_used; i++) { 1169 if (ssh_krl_check_key(krl, ca_used[i]) == 0) 1170 sig_seen = 1; 1171 else { 1172 sshkey_free(ca_used[i]); 1173 ca_used[i] = NULL; 1174 } 1175 } 1176 if (nca_used && !sig_seen) { 1177 error("All keys used to sign KRL were revoked"); 1178 r = SSH_ERR_KEY_REVOKED; 1179 goto out; 1180 } 1181 1182 /* If we have CA keys, then verify that one was used to sign the KRL */ 1183 if (sig_seen && nsign_ca_keys != 0) { 1184 sig_seen = 0; 1185 for (i = 0; !sig_seen && i < nsign_ca_keys; i++) { 1186 for (j = 0; j < nca_used; j++) { 1187 if (ca_used[j] == NULL) 1188 continue; 1189 if (sshkey_equal(ca_used[j], sign_ca_keys[i])) { 1190 sig_seen = 1; 1191 break; 1192 } 1193 } 1194 } 1195 if (!sig_seen) { 1196 r = SSH_ERR_SIGNATURE_INVALID; 1197 error("KRL not signed with any trusted key"); 1198 goto out; 1199 } 1200 } 1201 1202 *krlp = krl; 1203 r = 0; 1204 out: 1205 if (r != 0) 1206 ssh_krl_free(krl); 1207 for (i = 0; i < nca_used; i++) 1208 sshkey_free(ca_used[i]); 1209 free(ca_used); 1210 sshkey_free(key); 1211 sshbuf_free(copy); 1212 sshbuf_free(sect); 1213 return r; 1214 } 1215 1216 /* Checks certificate serial number and key ID revocation */ 1217 static int 1218 is_cert_revoked(const struct sshkey *key, struct revoked_certs *rc) 1219 { 1220 struct revoked_serial rs, *ers; 1221 struct revoked_key_id rki, *erki; 1222 1223 /* Check revocation by cert key ID */ 1224 memset(&rki, 0, sizeof(rki)); 1225 rki.key_id = key->cert->key_id; 1226 erki = RB_FIND(revoked_key_id_tree, &rc->revoked_key_ids, &rki); 1227 if (erki != NULL) { 1228 KRL_DBG(("%s: revoked by key ID", __func__)); 1229 return SSH_ERR_KEY_REVOKED; 1230 } 1231 1232 /* 1233 * Zero serials numbers are ignored (it's the default when the 1234 * CA doesn't specify one). 1235 */ 1236 if (key->cert->serial == 0) 1237 return 0; 1238 1239 memset(&rs, 0, sizeof(rs)); 1240 rs.lo = rs.hi = key->cert->serial; 1241 ers = RB_FIND(revoked_serial_tree, &rc->revoked_serials, &rs); 1242 if (ers != NULL) { 1243 KRL_DBG(("%s: revoked serial %llu matched %llu:%llu", __func__, 1244 key->cert->serial, ers->lo, ers->hi)); 1245 return SSH_ERR_KEY_REVOKED; 1246 } 1247 return 0; 1248 } 1249 1250 /* Checks whether a given key/cert is revoked. Does not check its CA */ 1251 static int 1252 is_key_revoked(struct ssh_krl *krl, const struct sshkey *key) 1253 { 1254 struct revoked_blob rb, *erb; 1255 struct revoked_certs *rc; 1256 int r; 1257 1258 /* Check explicitly revoked hashes first */ 1259 memset(&rb, 0, sizeof(rb)); 1260 if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA1, 1261 &rb.blob, &rb.len)) != 0) 1262 return r; 1263 erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha1s, &rb); 1264 free(rb.blob); 1265 if (erb != NULL) { 1266 KRL_DBG(("%s: revoked by key SHA1", __func__)); 1267 return SSH_ERR_KEY_REVOKED; 1268 } 1269 memset(&rb, 0, sizeof(rb)); 1270 if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA256, 1271 &rb.blob, &rb.len)) != 0) 1272 return r; 1273 erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha256s, &rb); 1274 free(rb.blob); 1275 if (erb != NULL) { 1276 KRL_DBG(("%s: revoked by key SHA256", __func__)); 1277 return SSH_ERR_KEY_REVOKED; 1278 } 1279 1280 /* Next, explicit keys */ 1281 memset(&rb, 0, sizeof(rb)); 1282 if ((r = plain_key_blob(key, &rb.blob, &rb.len)) != 0) 1283 return r; 1284 erb = RB_FIND(revoked_blob_tree, &krl->revoked_keys, &rb); 1285 free(rb.blob); 1286 if (erb != NULL) { 1287 KRL_DBG(("%s: revoked by explicit key", __func__)); 1288 return SSH_ERR_KEY_REVOKED; 1289 } 1290 1291 if (!sshkey_is_cert(key)) 1292 return 0; 1293 1294 /* Check cert revocation for the specified CA */ 1295 if ((r = revoked_certs_for_ca_key(krl, key->cert->signature_key, 1296 &rc, 0)) != 0) 1297 return r; 1298 if (rc != NULL) { 1299 if ((r = is_cert_revoked(key, rc)) != 0) 1300 return r; 1301 } 1302 /* Check cert revocation for the wildcard CA */ 1303 if ((r = revoked_certs_for_ca_key(krl, NULL, &rc, 0)) != 0) 1304 return r; 1305 if (rc != NULL) { 1306 if ((r = is_cert_revoked(key, rc)) != 0) 1307 return r; 1308 } 1309 1310 KRL_DBG(("%s: %llu no match", __func__, key->cert->serial)); 1311 return 0; 1312 } 1313 1314 int 1315 ssh_krl_check_key(struct ssh_krl *krl, const struct sshkey *key) 1316 { 1317 int r; 1318 1319 KRL_DBG(("%s: checking key", __func__)); 1320 if ((r = is_key_revoked(krl, key)) != 0) 1321 return r; 1322 if (sshkey_is_cert(key)) { 1323 debug2("%s: checking CA key", __func__); 1324 if ((r = is_key_revoked(krl, key->cert->signature_key)) != 0) 1325 return r; 1326 } 1327 KRL_DBG(("%s: key okay", __func__)); 1328 return 0; 1329 } 1330 1331 int 1332 ssh_krl_file_contains_key(const char *path, const struct sshkey *key) 1333 { 1334 struct sshbuf *krlbuf = NULL; 1335 struct ssh_krl *krl = NULL; 1336 int oerrno = 0, r, fd; 1337 1338 if (path == NULL) 1339 return 0; 1340 1341 if ((krlbuf = sshbuf_new()) == NULL) 1342 return SSH_ERR_ALLOC_FAIL; 1343 if ((fd = open(path, O_RDONLY)) == -1) { 1344 r = SSH_ERR_SYSTEM_ERROR; 1345 oerrno = errno; 1346 goto out; 1347 } 1348 if ((r = sshkey_load_file(fd, krlbuf)) != 0) { 1349 oerrno = errno; 1350 goto out; 1351 } 1352 if ((r = ssh_krl_from_blob(krlbuf, &krl, NULL, 0)) != 0) 1353 goto out; 1354 debug2("%s: checking KRL %s", __func__, path); 1355 r = ssh_krl_check_key(krl, key); 1356 out: 1357 if (fd != -1) 1358 close(fd); 1359 sshbuf_free(krlbuf); 1360 ssh_krl_free(krl); 1361 if (r != 0) 1362 errno = oerrno; 1363 return r; 1364 } 1365