1 /* $NetBSD: krl.c,v 1.14 2019/04/20 17:16:40 christos Exp $ */ 2 3 /* 4 * Copyright (c) 2012 Damien Miller <djm@mindrot.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 /* $OpenBSD: krl.c,v 1.42 2018/09/12 01:21:34 djm Exp $ */ 20 21 #include "includes.h" 22 __RCSID("$NetBSD: krl.c,v 1.14 2019/04/20 17:16:40 christos Exp $"); 23 #include <sys/param.h> /* MIN */ 24 #include <sys/types.h> 25 #include <sys/tree.h> 26 #include <sys/queue.h> 27 28 #include <errno.h> 29 #include <fcntl.h> 30 #include <limits.h> 31 #include <string.h> 32 #include <time.h> 33 #include <unistd.h> 34 35 #include "sshbuf.h" 36 #include "ssherr.h" 37 #include "sshkey.h" 38 #include "authfile.h" 39 #include "misc.h" 40 #include "log.h" 41 #include "digest.h" 42 #include "bitmap.h" 43 44 #include "krl.h" 45 46 /* #define DEBUG_KRL */ 47 #ifdef DEBUG_KRL 48 # define KRL_DBG(x) debug3 x 49 #else 50 # define KRL_DBG(x) 51 #endif 52 53 /* 54 * Trees of revoked serial numbers, key IDs and keys. This allows 55 * quick searching, querying and producing lists in canonical order. 56 */ 57 58 /* Tree of serial numbers. XXX make smarter: really need a real sparse bitmap */ 59 struct revoked_serial { 60 u_int64_t lo, hi; 61 RB_ENTRY(revoked_serial) tree_entry; 62 }; 63 static int serial_cmp(struct revoked_serial *a, struct revoked_serial *b); 64 RB_HEAD(revoked_serial_tree, revoked_serial); 65 RB_GENERATE_STATIC(revoked_serial_tree, revoked_serial, tree_entry, serial_cmp); 66 67 /* Tree of key IDs */ 68 struct revoked_key_id { 69 char *key_id; 70 RB_ENTRY(revoked_key_id) tree_entry; 71 }; 72 static int key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b); 73 RB_HEAD(revoked_key_id_tree, revoked_key_id); 74 RB_GENERATE_STATIC(revoked_key_id_tree, revoked_key_id, tree_entry, key_id_cmp); 75 76 /* Tree of blobs (used for keys and fingerprints) */ 77 struct revoked_blob { 78 u_char *blob; 79 size_t len; 80 RB_ENTRY(revoked_blob) tree_entry; 81 }; 82 static int blob_cmp(struct revoked_blob *a, struct revoked_blob *b); 83 RB_HEAD(revoked_blob_tree, revoked_blob); 84 RB_GENERATE_STATIC(revoked_blob_tree, revoked_blob, tree_entry, blob_cmp); 85 86 /* Tracks revoked certs for a single CA */ 87 struct revoked_certs { 88 struct sshkey *ca_key; 89 struct revoked_serial_tree revoked_serials; 90 struct revoked_key_id_tree revoked_key_ids; 91 TAILQ_ENTRY(revoked_certs) entry; 92 }; 93 TAILQ_HEAD(revoked_certs_list, revoked_certs); 94 95 struct ssh_krl { 96 u_int64_t krl_version; 97 u_int64_t generated_date; 98 u_int64_t flags; 99 char *comment; 100 struct revoked_blob_tree revoked_keys; 101 struct revoked_blob_tree revoked_sha1s; 102 struct revoked_blob_tree revoked_sha256s; 103 struct revoked_certs_list revoked_certs; 104 }; 105 106 /* Return equal if a and b overlap */ 107 static int 108 serial_cmp(struct revoked_serial *a, struct revoked_serial *b) 109 { 110 if (a->hi >= b->lo && a->lo <= b->hi) 111 return 0; 112 return a->lo < b->lo ? -1 : 1; 113 } 114 115 static int 116 key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b) 117 { 118 return strcmp(a->key_id, b->key_id); 119 } 120 121 static int 122 blob_cmp(struct revoked_blob *a, struct revoked_blob *b) 123 { 124 int r; 125 126 if (a->len != b->len) { 127 if ((r = memcmp(a->blob, b->blob, MINIMUM(a->len, b->len))) != 0) 128 return r; 129 return a->len > b->len ? 1 : -1; 130 } else 131 return memcmp(a->blob, b->blob, a->len); 132 } 133 134 struct ssh_krl * 135 ssh_krl_init(void) 136 { 137 struct ssh_krl *krl; 138 139 if ((krl = calloc(1, sizeof(*krl))) == NULL) 140 return NULL; 141 RB_INIT(&krl->revoked_keys); 142 RB_INIT(&krl->revoked_sha1s); 143 RB_INIT(&krl->revoked_sha256s); 144 TAILQ_INIT(&krl->revoked_certs); 145 return krl; 146 } 147 148 static void 149 revoked_certs_free(struct revoked_certs *rc) 150 { 151 struct revoked_serial *rs, *trs; 152 struct revoked_key_id *rki, *trki; 153 154 RB_FOREACH_SAFE(rs, revoked_serial_tree, &rc->revoked_serials, trs) { 155 RB_REMOVE(revoked_serial_tree, &rc->revoked_serials, rs); 156 free(rs); 157 } 158 RB_FOREACH_SAFE(rki, revoked_key_id_tree, &rc->revoked_key_ids, trki) { 159 RB_REMOVE(revoked_key_id_tree, &rc->revoked_key_ids, rki); 160 free(rki->key_id); 161 free(rki); 162 } 163 sshkey_free(rc->ca_key); 164 } 165 166 void 167 ssh_krl_free(struct ssh_krl *krl) 168 { 169 struct revoked_blob *rb, *trb; 170 struct revoked_certs *rc, *trc; 171 172 if (krl == NULL) 173 return; 174 175 free(krl->comment); 176 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_keys, trb) { 177 RB_REMOVE(revoked_blob_tree, &krl->revoked_keys, rb); 178 free(rb->blob); 179 free(rb); 180 } 181 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha1s, trb) { 182 RB_REMOVE(revoked_blob_tree, &krl->revoked_sha1s, rb); 183 free(rb->blob); 184 free(rb); 185 } 186 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha256s, trb) { 187 RB_REMOVE(revoked_blob_tree, &krl->revoked_sha256s, rb); 188 free(rb->blob); 189 free(rb); 190 } 191 TAILQ_FOREACH_SAFE(rc, &krl->revoked_certs, entry, trc) { 192 TAILQ_REMOVE(&krl->revoked_certs, rc, entry); 193 revoked_certs_free(rc); 194 } 195 } 196 197 void 198 ssh_krl_set_version(struct ssh_krl *krl, u_int64_t version) 199 { 200 krl->krl_version = version; 201 } 202 203 int 204 ssh_krl_set_comment(struct ssh_krl *krl, const char *comment) 205 { 206 free(krl->comment); 207 if ((krl->comment = strdup(comment)) == NULL) 208 return SSH_ERR_ALLOC_FAIL; 209 return 0; 210 } 211 212 /* 213 * Find the revoked_certs struct for a CA key. If allow_create is set then 214 * create a new one in the tree if one did not exist already. 215 */ 216 static int 217 revoked_certs_for_ca_key(struct ssh_krl *krl, const struct sshkey *ca_key, 218 struct revoked_certs **rcp, int allow_create) 219 { 220 struct revoked_certs *rc; 221 int r; 222 223 *rcp = NULL; 224 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { 225 if ((ca_key == NULL && rc->ca_key == NULL) || 226 sshkey_equal(rc->ca_key, ca_key)) { 227 *rcp = rc; 228 return 0; 229 } 230 } 231 if (!allow_create) 232 return 0; 233 /* If this CA doesn't exist in the list then add it now */ 234 if ((rc = calloc(1, sizeof(*rc))) == NULL) 235 return SSH_ERR_ALLOC_FAIL; 236 if (ca_key == NULL) 237 rc->ca_key = NULL; 238 else if ((r = sshkey_from_private(ca_key, &rc->ca_key)) != 0) { 239 free(rc); 240 return r; 241 } 242 RB_INIT(&rc->revoked_serials); 243 RB_INIT(&rc->revoked_key_ids); 244 TAILQ_INSERT_TAIL(&krl->revoked_certs, rc, entry); 245 KRL_DBG(("%s: new CA %s", __func__, 246 ca_key == NULL ? "*" : sshkey_type(ca_key))); 247 *rcp = rc; 248 return 0; 249 } 250 251 static int 252 insert_serial_range(struct revoked_serial_tree *rt, u_int64_t lo, u_int64_t hi) 253 { 254 struct revoked_serial rs, *ers, *crs, *irs; 255 256 KRL_DBG(("%s: insert %"PRIu64":%"PRIu64, __func__, lo, hi)); 257 memset(&rs, 0, sizeof(rs)); 258 rs.lo = lo; 259 rs.hi = hi; 260 ers = RB_NFIND(revoked_serial_tree, rt, &rs); 261 if (ers == NULL || serial_cmp(ers, &rs) != 0) { 262 /* No entry matches. Just insert */ 263 if ((irs = malloc(sizeof(rs))) == NULL) 264 return SSH_ERR_ALLOC_FAIL; 265 memcpy(irs, &rs, sizeof(*irs)); 266 ers = RB_INSERT(revoked_serial_tree, rt, irs); 267 if (ers != NULL) { 268 KRL_DBG(("%s: bad: ers != NULL", __func__)); 269 /* Shouldn't happen */ 270 free(irs); 271 return SSH_ERR_INTERNAL_ERROR; 272 } 273 ers = irs; 274 } else { 275 KRL_DBG(("%s: overlap found %"PRIu64":%"PRIu64, __func__, 276 ers->lo, ers->hi)); 277 /* 278 * The inserted entry overlaps an existing one. Grow the 279 * existing entry. 280 */ 281 if (ers->lo > lo) 282 ers->lo = lo; 283 if (ers->hi < hi) 284 ers->hi = hi; 285 } 286 287 /* 288 * The inserted or revised range might overlap or abut adjacent ones; 289 * coalesce as necessary. 290 */ 291 292 /* Check predecessors */ 293 while ((crs = RB_PREV(revoked_serial_tree, rt, ers)) != NULL) { 294 KRL_DBG(("%s: pred %"PRIu64":%"PRIu64, __func__, 295 crs->lo, crs->hi)); 296 if (ers->lo != 0 && crs->hi < ers->lo - 1) 297 break; 298 /* This entry overlaps. */ 299 if (crs->lo < ers->lo) { 300 ers->lo = crs->lo; 301 KRL_DBG(("%s: pred extend %"PRIu64":%"PRIu64, __func__, 302 ers->lo, ers->hi)); 303 } 304 RB_REMOVE(revoked_serial_tree, rt, crs); 305 free(crs); 306 } 307 /* Check successors */ 308 while ((crs = RB_NEXT(revoked_serial_tree, rt, ers)) != NULL) { 309 KRL_DBG(("%s: succ %"PRIu64":%"PRIu64, __func__, crs->lo, 310 crs->hi)); 311 if (ers->hi != (u_int64_t)-1 && crs->lo > ers->hi + 1) 312 break; 313 /* This entry overlaps. */ 314 if (crs->hi > ers->hi) { 315 ers->hi = crs->hi; 316 KRL_DBG(("%s: succ extend %"PRIu64":%"PRIu64, __func__, 317 ers->lo, ers->hi)); 318 } 319 RB_REMOVE(revoked_serial_tree, rt, crs); 320 free(crs); 321 } 322 KRL_DBG(("%s: done, final %"PRIu64":%"PRIu64, __func__, ers->lo, 323 ers->hi)); 324 return 0; 325 } 326 327 int 328 ssh_krl_revoke_cert_by_serial(struct ssh_krl *krl, const struct sshkey *ca_key, 329 u_int64_t serial) 330 { 331 return ssh_krl_revoke_cert_by_serial_range(krl, ca_key, serial, serial); 332 } 333 334 int 335 ssh_krl_revoke_cert_by_serial_range(struct ssh_krl *krl, 336 const struct sshkey *ca_key, u_int64_t lo, u_int64_t hi) 337 { 338 struct revoked_certs *rc; 339 int r; 340 341 if (lo > hi || lo == 0) 342 return SSH_ERR_INVALID_ARGUMENT; 343 if ((r = revoked_certs_for_ca_key(krl, ca_key, &rc, 1)) != 0) 344 return r; 345 return insert_serial_range(&rc->revoked_serials, lo, hi); 346 } 347 348 int 349 ssh_krl_revoke_cert_by_key_id(struct ssh_krl *krl, const struct sshkey *ca_key, 350 const char *key_id) 351 { 352 struct revoked_key_id *rki, *erki; 353 struct revoked_certs *rc; 354 int r; 355 356 if ((r = revoked_certs_for_ca_key(krl, ca_key, &rc, 1)) != 0) 357 return r; 358 359 KRL_DBG(("%s: revoke %s", __func__, key_id)); 360 if ((rki = calloc(1, sizeof(*rki))) == NULL || 361 (rki->key_id = strdup(key_id)) == NULL) { 362 free(rki); 363 return SSH_ERR_ALLOC_FAIL; 364 } 365 erki = RB_INSERT(revoked_key_id_tree, &rc->revoked_key_ids, rki); 366 if (erki != NULL) { 367 free(rki->key_id); 368 free(rki); 369 } 370 return 0; 371 } 372 373 /* Convert "key" to a public key blob without any certificate information */ 374 static int 375 plain_key_blob(const struct sshkey *key, u_char **blob, size_t *blen) 376 { 377 struct sshkey *kcopy; 378 int r; 379 380 if ((r = sshkey_from_private(key, &kcopy)) != 0) 381 return r; 382 if (sshkey_is_cert(kcopy)) { 383 if ((r = sshkey_drop_cert(kcopy)) != 0) { 384 sshkey_free(kcopy); 385 return r; 386 } 387 } 388 r = sshkey_to_blob(kcopy, blob, blen); 389 sshkey_free(kcopy); 390 return r; 391 } 392 393 /* Revoke a key blob. Ownership of blob is transferred to the tree */ 394 static int 395 revoke_blob(struct revoked_blob_tree *rbt, u_char *blob, size_t len) 396 { 397 struct revoked_blob *rb, *erb; 398 399 if ((rb = calloc(1, sizeof(*rb))) == NULL) 400 return SSH_ERR_ALLOC_FAIL; 401 rb->blob = blob; 402 rb->len = len; 403 erb = RB_INSERT(revoked_blob_tree, rbt, rb); 404 if (erb != NULL) { 405 free(rb->blob); 406 free(rb); 407 } 408 return 0; 409 } 410 411 int 412 ssh_krl_revoke_key_explicit(struct ssh_krl *krl, const struct sshkey *key) 413 { 414 u_char *blob; 415 size_t len; 416 int r; 417 418 debug3("%s: revoke type %s", __func__, sshkey_type(key)); 419 if ((r = plain_key_blob(key, &blob, &len)) != 0) 420 return r; 421 return revoke_blob(&krl->revoked_keys, blob, len); 422 } 423 424 static int 425 revoke_by_hash(struct revoked_blob_tree *target, const u_char *p, size_t len) 426 { 427 u_char *blob; 428 int r; 429 430 /* need to copy hash, as revoke_blob steals ownership */ 431 if ((blob = malloc(len)) == NULL) 432 return SSH_ERR_SYSTEM_ERROR; 433 memcpy(blob, p, len); 434 if ((r = revoke_blob(target, blob, len)) != 0) { 435 free(blob); 436 return r; 437 } 438 return 0; 439 } 440 441 int 442 ssh_krl_revoke_key_sha1(struct ssh_krl *krl, const u_char *p, size_t len) 443 { 444 debug3("%s: revoke by sha1", __func__); 445 if (len != 20) 446 return SSH_ERR_INVALID_FORMAT; 447 return revoke_by_hash(&krl->revoked_sha1s, p, len); 448 } 449 450 int 451 ssh_krl_revoke_key_sha256(struct ssh_krl *krl, const u_char *p, size_t len) 452 { 453 debug3("%s: revoke by sha256", __func__); 454 if (len != 32) 455 return SSH_ERR_INVALID_FORMAT; 456 return revoke_by_hash(&krl->revoked_sha256s, p, len); 457 } 458 459 int 460 ssh_krl_revoke_key(struct ssh_krl *krl, const struct sshkey *key) 461 { 462 /* XXX replace with SHA256? */ 463 if (!sshkey_is_cert(key)) 464 return ssh_krl_revoke_key_explicit(krl, key); 465 466 if (key->cert->serial == 0) { 467 return ssh_krl_revoke_cert_by_key_id(krl, 468 key->cert->signature_key, 469 key->cert->key_id); 470 } else { 471 return ssh_krl_revoke_cert_by_serial(krl, 472 key->cert->signature_key, 473 key->cert->serial); 474 } 475 } 476 477 /* 478 * Select the most compact section type to emit next in a KRL based on 479 * the current section type, the run length of contiguous revoked serial 480 * numbers and the gaps from the last and to the next revoked serial. 481 * Applies a mostly-accurate bit cost model to select the section type 482 * that will minimise the size of the resultant KRL. 483 */ 484 static int 485 choose_next_state(int current_state, u_int64_t contig, int final, 486 u_int64_t last_gap, u_int64_t next_gap, int *force_new_section) 487 { 488 int new_state; 489 u_int64_t cost, cost_list, cost_range, cost_bitmap, cost_bitmap_restart; 490 491 /* 492 * Avoid unsigned overflows. 493 * The limits are high enough to avoid confusing the calculations. 494 */ 495 contig = MINIMUM(contig, 1ULL<<31); 496 last_gap = MINIMUM(last_gap, 1ULL<<31); 497 next_gap = MINIMUM(next_gap, 1ULL<<31); 498 499 /* 500 * Calculate the cost to switch from the current state to candidates. 501 * NB. range sections only ever contain a single range, so their 502 * switching cost is independent of the current_state. 503 */ 504 cost_list = cost_bitmap = cost_bitmap_restart = 0; 505 cost_range = 8; 506 switch (current_state) { 507 case KRL_SECTION_CERT_SERIAL_LIST: 508 cost_bitmap_restart = cost_bitmap = 8 + 64; 509 break; 510 case KRL_SECTION_CERT_SERIAL_BITMAP: 511 cost_list = 8; 512 cost_bitmap_restart = 8 + 64; 513 break; 514 case KRL_SECTION_CERT_SERIAL_RANGE: 515 case 0: 516 cost_bitmap_restart = cost_bitmap = 8 + 64; 517 cost_list = 8; 518 } 519 520 /* Estimate base cost in bits of each section type */ 521 cost_list += 64 * contig + (final ? 0 : 8+64); 522 cost_range += (2 * 64) + (final ? 0 : 8+64); 523 cost_bitmap += last_gap + contig + (final ? 0 : MINIMUM(next_gap, 8+64)); 524 cost_bitmap_restart += contig + (final ? 0 : MINIMUM(next_gap, 8+64)); 525 526 /* Convert to byte costs for actual comparison */ 527 cost_list = (cost_list + 7) / 8; 528 cost_bitmap = (cost_bitmap + 7) / 8; 529 cost_bitmap_restart = (cost_bitmap_restart + 7) / 8; 530 cost_range = (cost_range + 7) / 8; 531 532 /* Now pick the best choice */ 533 *force_new_section = 0; 534 new_state = KRL_SECTION_CERT_SERIAL_BITMAP; 535 cost = cost_bitmap; 536 if (cost_range < cost) { 537 new_state = KRL_SECTION_CERT_SERIAL_RANGE; 538 cost = cost_range; 539 } 540 if (cost_list < cost) { 541 new_state = KRL_SECTION_CERT_SERIAL_LIST; 542 cost = cost_list; 543 } 544 if (cost_bitmap_restart < cost) { 545 new_state = KRL_SECTION_CERT_SERIAL_BITMAP; 546 *force_new_section = 1; 547 cost = cost_bitmap_restart; 548 } 549 KRL_DBG(("%s: contig %llu last_gap %llu next_gap %llu final %d, costs:" 550 "list %llu range %llu bitmap %llu new bitmap %llu, " 551 "selected 0x%02x%s", __func__, (long long unsigned)contig, 552 (long long unsigned)last_gap, (long long unsigned)next_gap, final, 553 (long long unsigned)cost_list, (long long unsigned)cost_range, 554 (long long unsigned)cost_bitmap, 555 (long long unsigned)cost_bitmap_restart, new_state, 556 *force_new_section ? " restart" : "")); 557 return new_state; 558 } 559 560 static int 561 put_bitmap(struct sshbuf *buf, struct bitmap *bitmap) 562 { 563 size_t len; 564 u_char *blob; 565 int r; 566 567 len = bitmap_nbytes(bitmap); 568 if ((blob = malloc(len)) == NULL) 569 return SSH_ERR_ALLOC_FAIL; 570 if (bitmap_to_string(bitmap, blob, len) != 0) { 571 free(blob); 572 return SSH_ERR_INTERNAL_ERROR; 573 } 574 r = sshbuf_put_bignum2_bytes(buf, blob, len); 575 free(blob); 576 return r; 577 } 578 579 /* Generate a KRL_SECTION_CERTIFICATES KRL section */ 580 static int 581 revoked_certs_generate(struct revoked_certs *rc, struct sshbuf *buf) 582 { 583 int final, force_new_sect, r = SSH_ERR_INTERNAL_ERROR; 584 u_int64_t i, contig, gap, last = 0, bitmap_start = 0; 585 struct revoked_serial *rs, *nrs; 586 struct revoked_key_id *rki; 587 int next_state, state = 0; 588 struct sshbuf *sect; 589 struct bitmap *bitmap = NULL; 590 591 if ((sect = sshbuf_new()) == NULL) 592 return SSH_ERR_ALLOC_FAIL; 593 594 /* Store the header: optional CA scope key, reserved */ 595 if (rc->ca_key == NULL) { 596 if ((r = sshbuf_put_string(buf, NULL, 0)) != 0) 597 goto out; 598 } else { 599 if ((r = sshkey_puts(rc->ca_key, buf)) != 0) 600 goto out; 601 } 602 if ((r = sshbuf_put_string(buf, NULL, 0)) != 0) 603 goto out; 604 605 /* Store the revoked serials. */ 606 for (rs = RB_MIN(revoked_serial_tree, &rc->revoked_serials); 607 rs != NULL; 608 rs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs)) { 609 KRL_DBG(("%s: serial %llu:%llu state 0x%02x", __func__, 610 (long long unsigned)rs->lo, (long long unsigned)rs->hi, 611 state)); 612 613 /* Check contiguous length and gap to next section (if any) */ 614 nrs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs); 615 final = nrs == NULL; 616 gap = nrs == NULL ? 0 : nrs->lo - rs->hi; 617 contig = 1 + (rs->hi - rs->lo); 618 619 /* Choose next state based on these */ 620 next_state = choose_next_state(state, contig, final, 621 state == 0 ? 0 : rs->lo - last, gap, &force_new_sect); 622 623 /* 624 * If the current section is a range section or has a different 625 * type to the next section, then finish it off now. 626 */ 627 if (state != 0 && (force_new_sect || next_state != state || 628 state == KRL_SECTION_CERT_SERIAL_RANGE)) { 629 KRL_DBG(("%s: finish state 0x%02x", __func__, state)); 630 switch (state) { 631 case KRL_SECTION_CERT_SERIAL_LIST: 632 case KRL_SECTION_CERT_SERIAL_RANGE: 633 break; 634 case KRL_SECTION_CERT_SERIAL_BITMAP: 635 if ((r = put_bitmap(sect, bitmap)) != 0) 636 goto out; 637 bitmap_free(bitmap); 638 bitmap = NULL; 639 break; 640 } 641 if ((r = sshbuf_put_u8(buf, state)) != 0 || 642 (r = sshbuf_put_stringb(buf, sect)) != 0) 643 goto out; 644 sshbuf_reset(sect); 645 } 646 647 /* If we are starting a new section then prepare it now */ 648 if (next_state != state || force_new_sect) { 649 KRL_DBG(("%s: start state 0x%02x", __func__, 650 next_state)); 651 state = next_state; 652 sshbuf_reset(sect); 653 switch (state) { 654 case KRL_SECTION_CERT_SERIAL_LIST: 655 case KRL_SECTION_CERT_SERIAL_RANGE: 656 break; 657 case KRL_SECTION_CERT_SERIAL_BITMAP: 658 if ((bitmap = bitmap_new()) == NULL) { 659 r = SSH_ERR_ALLOC_FAIL; 660 goto out; 661 } 662 bitmap_start = rs->lo; 663 if ((r = sshbuf_put_u64(sect, 664 bitmap_start)) != 0) 665 goto out; 666 break; 667 } 668 } 669 670 /* Perform section-specific processing */ 671 switch (state) { 672 case KRL_SECTION_CERT_SERIAL_LIST: 673 for (i = 0; i < contig; i++) { 674 if ((r = sshbuf_put_u64(sect, rs->lo + i)) != 0) 675 goto out; 676 } 677 break; 678 case KRL_SECTION_CERT_SERIAL_RANGE: 679 if ((r = sshbuf_put_u64(sect, rs->lo)) != 0 || 680 (r = sshbuf_put_u64(sect, rs->hi)) != 0) 681 goto out; 682 break; 683 case KRL_SECTION_CERT_SERIAL_BITMAP: 684 if (rs->lo - bitmap_start > INT_MAX) { 685 error("%s: insane bitmap gap", __func__); 686 goto out; 687 } 688 for (i = 0; i < contig; i++) { 689 if (bitmap_set_bit(bitmap, 690 rs->lo + i - bitmap_start) != 0) { 691 r = SSH_ERR_ALLOC_FAIL; 692 goto out; 693 } 694 } 695 break; 696 } 697 last = rs->hi; 698 } 699 /* Flush the remaining section, if any */ 700 if (state != 0) { 701 KRL_DBG(("%s: serial final flush for state 0x%02x", 702 __func__, state)); 703 switch (state) { 704 case KRL_SECTION_CERT_SERIAL_LIST: 705 case KRL_SECTION_CERT_SERIAL_RANGE: 706 break; 707 case KRL_SECTION_CERT_SERIAL_BITMAP: 708 if ((r = put_bitmap(sect, bitmap)) != 0) 709 goto out; 710 bitmap_free(bitmap); 711 bitmap = NULL; 712 break; 713 } 714 if ((r = sshbuf_put_u8(buf, state)) != 0 || 715 (r = sshbuf_put_stringb(buf, sect)) != 0) 716 goto out; 717 } 718 KRL_DBG(("%s: serial done ", __func__)); 719 720 /* Now output a section for any revocations by key ID */ 721 sshbuf_reset(sect); 722 RB_FOREACH(rki, revoked_key_id_tree, &rc->revoked_key_ids) { 723 KRL_DBG(("%s: key ID %s", __func__, rki->key_id)); 724 if ((r = sshbuf_put_cstring(sect, rki->key_id)) != 0) 725 goto out; 726 } 727 if (sshbuf_len(sect) != 0) { 728 if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERT_KEY_ID)) != 0 || 729 (r = sshbuf_put_stringb(buf, sect)) != 0) 730 goto out; 731 } 732 r = 0; 733 out: 734 bitmap_free(bitmap); 735 sshbuf_free(sect); 736 return r; 737 } 738 739 int 740 ssh_krl_to_blob(struct ssh_krl *krl, struct sshbuf *buf, 741 const struct sshkey **sign_keys, u_int nsign_keys) 742 { 743 int r = SSH_ERR_INTERNAL_ERROR; 744 struct revoked_certs *rc; 745 struct revoked_blob *rb; 746 struct sshbuf *sect; 747 u_char *sblob = NULL; 748 size_t slen, i; 749 750 if (krl->generated_date == 0) 751 krl->generated_date = time(NULL); 752 753 if ((sect = sshbuf_new()) == NULL) 754 return SSH_ERR_ALLOC_FAIL; 755 756 /* Store the header */ 757 if ((r = sshbuf_put(buf, KRL_MAGIC, sizeof(KRL_MAGIC) - 1)) != 0 || 758 (r = sshbuf_put_u32(buf, KRL_FORMAT_VERSION)) != 0 || 759 (r = sshbuf_put_u64(buf, krl->krl_version)) != 0 || 760 (r = sshbuf_put_u64(buf, krl->generated_date)) != 0 || 761 (r = sshbuf_put_u64(buf, krl->flags)) != 0 || 762 (r = sshbuf_put_string(buf, NULL, 0)) != 0 || 763 (r = sshbuf_put_cstring(buf, krl->comment)) != 0) 764 goto out; 765 766 /* Store sections for revoked certificates */ 767 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { 768 sshbuf_reset(sect); 769 if ((r = revoked_certs_generate(rc, sect)) != 0) 770 goto out; 771 if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERTIFICATES)) != 0 || 772 (r = sshbuf_put_stringb(buf, sect)) != 0) 773 goto out; 774 } 775 776 /* Finally, output sections for revocations by public key/hash */ 777 sshbuf_reset(sect); 778 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_keys) { 779 KRL_DBG(("%s: key len %zu ", __func__, rb->len)); 780 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 781 goto out; 782 } 783 if (sshbuf_len(sect) != 0) { 784 if ((r = sshbuf_put_u8(buf, KRL_SECTION_EXPLICIT_KEY)) != 0 || 785 (r = sshbuf_put_stringb(buf, sect)) != 0) 786 goto out; 787 } 788 sshbuf_reset(sect); 789 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha1s) { 790 KRL_DBG(("%s: hash len %zu ", __func__, rb->len)); 791 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 792 goto out; 793 } 794 if (sshbuf_len(sect) != 0) { 795 if ((r = sshbuf_put_u8(buf, 796 KRL_SECTION_FINGERPRINT_SHA1)) != 0 || 797 (r = sshbuf_put_stringb(buf, sect)) != 0) 798 goto out; 799 } 800 sshbuf_reset(sect); 801 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha256s) { 802 KRL_DBG(("%s: hash len %zu ", __func__, rb->len)); 803 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 804 goto out; 805 } 806 if (sshbuf_len(sect) != 0) { 807 if ((r = sshbuf_put_u8(buf, 808 KRL_SECTION_FINGERPRINT_SHA256)) != 0 || 809 (r = sshbuf_put_stringb(buf, sect)) != 0) 810 goto out; 811 } 812 813 for (i = 0; i < nsign_keys; i++) { 814 KRL_DBG(("%s: signature key %s", __func__, 815 sshkey_ssh_name(sign_keys[i]))); 816 if ((r = sshbuf_put_u8(buf, KRL_SECTION_SIGNATURE)) != 0 || 817 (r = sshkey_puts(sign_keys[i], buf)) != 0) 818 goto out; 819 820 if ((r = sshkey_sign(sign_keys[i], &sblob, &slen, 821 sshbuf_ptr(buf), sshbuf_len(buf), NULL, 0)) != 0) 822 goto out; 823 KRL_DBG(("%s: signature sig len %zu", __func__, slen)); 824 if ((r = sshbuf_put_string(buf, sblob, slen)) != 0) 825 goto out; 826 } 827 828 r = 0; 829 out: 830 free(sblob); 831 sshbuf_free(sect); 832 return r; 833 } 834 835 static void 836 format_timestamp(u_int64_t timestamp, char *ts, size_t nts) 837 { 838 time_t t; 839 struct tm *tm; 840 841 t = timestamp; 842 tm = localtime(&t); 843 if (tm == NULL) 844 strlcpy(ts, "<INVALID>", nts); 845 else { 846 *ts = '\0'; 847 strftime(ts, nts, "%Y%m%dT%H%M%S", tm); 848 } 849 } 850 851 static int 852 parse_revoked_certs(struct sshbuf *buf, struct ssh_krl *krl) 853 { 854 int r = SSH_ERR_INTERNAL_ERROR; 855 u_char type; 856 const u_char *blob; 857 size_t blen, nbits; 858 struct sshbuf *subsect = NULL; 859 u_int64_t serial, serial_lo, serial_hi; 860 struct bitmap *bitmap = NULL; 861 char *key_id = NULL; 862 struct sshkey *ca_key = NULL; 863 864 if ((subsect = sshbuf_new()) == NULL) 865 return SSH_ERR_ALLOC_FAIL; 866 867 /* Header: key, reserved */ 868 if ((r = sshbuf_get_string_direct(buf, &blob, &blen)) != 0 || 869 (r = sshbuf_skip_string(buf)) != 0) 870 goto out; 871 if (blen != 0 && (r = sshkey_from_blob(blob, blen, &ca_key)) != 0) 872 goto out; 873 874 while (sshbuf_len(buf) > 0) { 875 sshbuf_free(subsect); 876 subsect = NULL; 877 if ((r = sshbuf_get_u8(buf, &type)) != 0 || 878 (r = sshbuf_froms(buf, &subsect)) != 0) 879 goto out; 880 KRL_DBG(("%s: subsection type 0x%02x", __func__, type)); 881 /* sshbuf_dump(subsect, stderr); */ 882 883 switch (type) { 884 case KRL_SECTION_CERT_SERIAL_LIST: 885 while (sshbuf_len(subsect) > 0) { 886 if ((r = sshbuf_get_u64(subsect, &serial)) != 0) 887 goto out; 888 if ((r = ssh_krl_revoke_cert_by_serial(krl, 889 ca_key, serial)) != 0) 890 goto out; 891 } 892 break; 893 case KRL_SECTION_CERT_SERIAL_RANGE: 894 if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 || 895 (r = sshbuf_get_u64(subsect, &serial_hi)) != 0) 896 goto out; 897 if ((r = ssh_krl_revoke_cert_by_serial_range(krl, 898 ca_key, serial_lo, serial_hi)) != 0) 899 goto out; 900 break; 901 case KRL_SECTION_CERT_SERIAL_BITMAP: 902 if ((bitmap = bitmap_new()) == NULL) { 903 r = SSH_ERR_ALLOC_FAIL; 904 goto out; 905 } 906 if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 || 907 (r = sshbuf_get_bignum2_bytes_direct(subsect, 908 &blob, &blen)) != 0) 909 goto out; 910 if (bitmap_from_string(bitmap, blob, blen) != 0) { 911 r = SSH_ERR_INVALID_FORMAT; 912 goto out; 913 } 914 nbits = bitmap_nbits(bitmap); 915 for (serial = 0; serial < (u_int64_t)nbits; serial++) { 916 if (serial > 0 && serial_lo + serial == 0) { 917 error("%s: bitmap wraps u64", __func__); 918 r = SSH_ERR_INVALID_FORMAT; 919 goto out; 920 } 921 if (!bitmap_test_bit(bitmap, serial)) 922 continue; 923 if ((r = ssh_krl_revoke_cert_by_serial(krl, 924 ca_key, serial_lo + serial)) != 0) 925 goto out; 926 } 927 bitmap_free(bitmap); 928 bitmap = NULL; 929 break; 930 case KRL_SECTION_CERT_KEY_ID: 931 while (sshbuf_len(subsect) > 0) { 932 if ((r = sshbuf_get_cstring(subsect, 933 &key_id, NULL)) != 0) 934 goto out; 935 if ((r = ssh_krl_revoke_cert_by_key_id(krl, 936 ca_key, key_id)) != 0) 937 goto out; 938 free(key_id); 939 key_id = NULL; 940 } 941 break; 942 default: 943 error("Unsupported KRL certificate section %u", type); 944 r = SSH_ERR_INVALID_FORMAT; 945 goto out; 946 } 947 if (sshbuf_len(subsect) > 0) { 948 error("KRL certificate section contains unparsed data"); 949 r = SSH_ERR_INVALID_FORMAT; 950 goto out; 951 } 952 } 953 954 r = 0; 955 out: 956 if (bitmap != NULL) 957 bitmap_free(bitmap); 958 free(key_id); 959 sshkey_free(ca_key); 960 sshbuf_free(subsect); 961 return r; 962 } 963 964 static int 965 blob_section(struct sshbuf *sect, struct revoked_blob_tree *target_tree, 966 size_t expected_len) 967 { 968 u_char *rdata = NULL; 969 size_t rlen = 0; 970 int r; 971 972 while (sshbuf_len(sect) > 0) { 973 if ((r = sshbuf_get_string(sect, &rdata, &rlen)) != 0) 974 return r; 975 if (expected_len != 0 && rlen != expected_len) { 976 error("%s: bad length", __func__); 977 free(rdata); 978 return SSH_ERR_INVALID_FORMAT; 979 } 980 if ((r = revoke_blob(target_tree, rdata, rlen)) != 0) { 981 free(rdata); 982 return r; 983 } 984 } 985 return 0; 986 } 987 988 /* Attempt to parse a KRL, checking its signature (if any) with sign_ca_keys. */ 989 int 990 ssh_krl_from_blob(struct sshbuf *buf, struct ssh_krl **krlp, 991 const struct sshkey **sign_ca_keys, size_t nsign_ca_keys) 992 { 993 struct sshbuf *copy = NULL, *sect = NULL; 994 struct ssh_krl *krl = NULL; 995 char timestamp[64]; 996 int r = SSH_ERR_INTERNAL_ERROR, sig_seen; 997 struct sshkey *key = NULL, **ca_used = NULL, **tmp_ca_used; 998 u_char type; 999 const u_char *blob; 1000 size_t i, j, sig_off, sects_off, blen, nca_used; 1001 u_int format_version; 1002 1003 nca_used = 0; 1004 *krlp = NULL; 1005 if (sshbuf_len(buf) < sizeof(KRL_MAGIC) - 1 || 1006 memcmp(sshbuf_ptr(buf), KRL_MAGIC, sizeof(KRL_MAGIC) - 1) != 0) { 1007 debug3("%s: not a KRL", __func__); 1008 return SSH_ERR_KRL_BAD_MAGIC; 1009 } 1010 1011 /* Take a copy of the KRL buffer so we can verify its signature later */ 1012 if ((copy = sshbuf_fromb(buf)) == NULL) { 1013 r = SSH_ERR_ALLOC_FAIL; 1014 goto out; 1015 } 1016 if ((r = sshbuf_consume(copy, sizeof(KRL_MAGIC) - 1)) != 0) 1017 goto out; 1018 1019 if ((krl = ssh_krl_init()) == NULL) { 1020 error("%s: alloc failed", __func__); 1021 goto out; 1022 } 1023 1024 if ((r = sshbuf_get_u32(copy, &format_version)) != 0) 1025 goto out; 1026 if (format_version != KRL_FORMAT_VERSION) { 1027 r = SSH_ERR_INVALID_FORMAT; 1028 goto out; 1029 } 1030 if ((r = sshbuf_get_u64(copy, &krl->krl_version)) != 0 || 1031 (r = sshbuf_get_u64(copy, &krl->generated_date)) != 0 || 1032 (r = sshbuf_get_u64(copy, &krl->flags)) != 0 || 1033 (r = sshbuf_skip_string(copy)) != 0 || 1034 (r = sshbuf_get_cstring(copy, &krl->comment, NULL)) != 0) 1035 goto out; 1036 1037 format_timestamp(krl->generated_date, timestamp, sizeof(timestamp)); 1038 debug("KRL version %llu generated at %s%s%s", 1039 (long long unsigned)krl->krl_version, timestamp, 1040 *krl->comment ? ": " : "", krl->comment); 1041 1042 /* 1043 * 1st pass: verify signatures, if any. This is done to avoid 1044 * detailed parsing of data whose provenance is unverified. 1045 */ 1046 sig_seen = 0; 1047 if (sshbuf_len(buf) < sshbuf_len(copy)) { 1048 /* Shouldn't happen */ 1049 r = SSH_ERR_INTERNAL_ERROR; 1050 goto out; 1051 } 1052 sects_off = sshbuf_len(buf) - sshbuf_len(copy); 1053 while (sshbuf_len(copy) > 0) { 1054 if ((r = sshbuf_get_u8(copy, &type)) != 0 || 1055 (r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0) 1056 goto out; 1057 KRL_DBG(("%s: first pass, section 0x%02x", __func__, type)); 1058 if (type != KRL_SECTION_SIGNATURE) { 1059 if (sig_seen) { 1060 error("KRL contains non-signature section " 1061 "after signature"); 1062 r = SSH_ERR_INVALID_FORMAT; 1063 goto out; 1064 } 1065 /* Not interested for now. */ 1066 continue; 1067 } 1068 sig_seen = 1; 1069 /* First string component is the signing key */ 1070 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 1071 r = SSH_ERR_INVALID_FORMAT; 1072 goto out; 1073 } 1074 if (sshbuf_len(buf) < sshbuf_len(copy)) { 1075 /* Shouldn't happen */ 1076 r = SSH_ERR_INTERNAL_ERROR; 1077 goto out; 1078 } 1079 sig_off = sshbuf_len(buf) - sshbuf_len(copy); 1080 /* Second string component is the signature itself */ 1081 if ((r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0) { 1082 r = SSH_ERR_INVALID_FORMAT; 1083 goto out; 1084 } 1085 /* Check signature over entire KRL up to this point */ 1086 if ((r = sshkey_verify(key, blob, blen, 1087 sshbuf_ptr(buf), sig_off, NULL, 0)) != 0) 1088 goto out; 1089 /* Check if this key has already signed this KRL */ 1090 for (i = 0; i < nca_used; i++) { 1091 if (sshkey_equal(ca_used[i], key)) { 1092 error("KRL signed more than once with " 1093 "the same key"); 1094 r = SSH_ERR_INVALID_FORMAT; 1095 goto out; 1096 } 1097 } 1098 /* Record keys used to sign the KRL */ 1099 tmp_ca_used = recallocarray(ca_used, nca_used, nca_used + 1, 1100 sizeof(*ca_used)); 1101 if (tmp_ca_used == NULL) { 1102 r = SSH_ERR_ALLOC_FAIL; 1103 goto out; 1104 } 1105 ca_used = tmp_ca_used; 1106 ca_used[nca_used++] = key; 1107 key = NULL; 1108 } 1109 1110 if (sshbuf_len(copy) != 0) { 1111 /* Shouldn't happen */ 1112 r = SSH_ERR_INTERNAL_ERROR; 1113 goto out; 1114 } 1115 1116 /* 1117 * 2nd pass: parse and load the KRL, skipping the header to the point 1118 * where the section start. 1119 */ 1120 sshbuf_free(copy); 1121 if ((copy = sshbuf_fromb(buf)) == NULL) { 1122 r = SSH_ERR_ALLOC_FAIL; 1123 goto out; 1124 } 1125 if ((r = sshbuf_consume(copy, sects_off)) != 0) 1126 goto out; 1127 while (sshbuf_len(copy) > 0) { 1128 sshbuf_free(sect); 1129 sect = NULL; 1130 if ((r = sshbuf_get_u8(copy, &type)) != 0 || 1131 (r = sshbuf_froms(copy, §)) != 0) 1132 goto out; 1133 KRL_DBG(("%s: second pass, section 0x%02x", __func__, type)); 1134 1135 switch (type) { 1136 case KRL_SECTION_CERTIFICATES: 1137 if ((r = parse_revoked_certs(sect, krl)) != 0) 1138 goto out; 1139 break; 1140 case KRL_SECTION_EXPLICIT_KEY: 1141 if ((r = blob_section(sect, 1142 &krl->revoked_keys, 0)) != 0) 1143 goto out; 1144 break; 1145 case KRL_SECTION_FINGERPRINT_SHA1: 1146 if ((r = blob_section(sect, 1147 &krl->revoked_sha1s, 20)) != 0) 1148 goto out; 1149 break; 1150 case KRL_SECTION_FINGERPRINT_SHA256: 1151 if ((r = blob_section(sect, 1152 &krl->revoked_sha256s, 32)) != 0) 1153 goto out; 1154 break; 1155 case KRL_SECTION_SIGNATURE: 1156 /* Handled above, but still need to stay in synch */ 1157 sshbuf_free(sect); 1158 sect = NULL; 1159 if ((r = sshbuf_skip_string(copy)) != 0) 1160 goto out; 1161 break; 1162 default: 1163 error("Unsupported KRL section %u", type); 1164 r = SSH_ERR_INVALID_FORMAT; 1165 goto out; 1166 } 1167 if (sect != NULL && sshbuf_len(sect) > 0) { 1168 error("KRL section contains unparsed data"); 1169 r = SSH_ERR_INVALID_FORMAT; 1170 goto out; 1171 } 1172 } 1173 1174 /* Check that the key(s) used to sign the KRL weren't revoked */ 1175 sig_seen = 0; 1176 for (i = 0; i < nca_used; i++) { 1177 if (ssh_krl_check_key(krl, ca_used[i]) == 0) 1178 sig_seen = 1; 1179 else { 1180 sshkey_free(ca_used[i]); 1181 ca_used[i] = NULL; 1182 } 1183 } 1184 if (nca_used && !sig_seen) { 1185 error("All keys used to sign KRL were revoked"); 1186 r = SSH_ERR_KEY_REVOKED; 1187 goto out; 1188 } 1189 1190 /* If we have CA keys, then verify that one was used to sign the KRL */ 1191 if (sig_seen && nsign_ca_keys != 0) { 1192 sig_seen = 0; 1193 for (i = 0; !sig_seen && i < nsign_ca_keys; i++) { 1194 for (j = 0; j < nca_used; j++) { 1195 if (ca_used[j] == NULL) 1196 continue; 1197 if (sshkey_equal(ca_used[j], sign_ca_keys[i])) { 1198 sig_seen = 1; 1199 break; 1200 } 1201 } 1202 } 1203 if (!sig_seen) { 1204 r = SSH_ERR_SIGNATURE_INVALID; 1205 error("KRL not signed with any trusted key"); 1206 goto out; 1207 } 1208 } 1209 1210 *krlp = krl; 1211 r = 0; 1212 out: 1213 if (r != 0) 1214 ssh_krl_free(krl); 1215 for (i = 0; i < nca_used; i++) 1216 sshkey_free(ca_used[i]); 1217 free(ca_used); 1218 sshkey_free(key); 1219 sshbuf_free(copy); 1220 sshbuf_free(sect); 1221 return r; 1222 } 1223 1224 /* Checks certificate serial number and key ID revocation */ 1225 static int 1226 is_cert_revoked(const struct sshkey *key, struct revoked_certs *rc) 1227 { 1228 struct revoked_serial rs, *ers; 1229 struct revoked_key_id rki, *erki; 1230 1231 /* Check revocation by cert key ID */ 1232 memset(&rki, 0, sizeof(rki)); 1233 rki.key_id = key->cert->key_id; 1234 erki = RB_FIND(revoked_key_id_tree, &rc->revoked_key_ids, &rki); 1235 if (erki != NULL) { 1236 KRL_DBG(("%s: revoked by key ID", __func__)); 1237 return SSH_ERR_KEY_REVOKED; 1238 } 1239 1240 /* 1241 * Zero serials numbers are ignored (it's the default when the 1242 * CA doesn't specify one). 1243 */ 1244 if (key->cert->serial == 0) 1245 return 0; 1246 1247 memset(&rs, 0, sizeof(rs)); 1248 rs.lo = rs.hi = key->cert->serial; 1249 ers = RB_FIND(revoked_serial_tree, &rc->revoked_serials, &rs); 1250 if (ers != NULL) { 1251 KRL_DBG(("%s: revoked serial %llu matched %llu:%llu", __func__, 1252 key->cert->serial, ers->lo, ers->hi)); 1253 return SSH_ERR_KEY_REVOKED; 1254 } 1255 return 0; 1256 } 1257 1258 /* Checks whether a given key/cert is revoked. Does not check its CA */ 1259 static int 1260 is_key_revoked(struct ssh_krl *krl, const struct sshkey *key) 1261 { 1262 struct revoked_blob rb, *erb; 1263 struct revoked_certs *rc; 1264 int r; 1265 1266 /* Check explicitly revoked hashes first */ 1267 memset(&rb, 0, sizeof(rb)); 1268 if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA1, 1269 &rb.blob, &rb.len)) != 0) 1270 return r; 1271 erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha1s, &rb); 1272 free(rb.blob); 1273 if (erb != NULL) { 1274 KRL_DBG(("%s: revoked by key SHA1", __func__)); 1275 return SSH_ERR_KEY_REVOKED; 1276 } 1277 memset(&rb, 0, sizeof(rb)); 1278 if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA256, 1279 &rb.blob, &rb.len)) != 0) 1280 return r; 1281 erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha256s, &rb); 1282 free(rb.blob); 1283 if (erb != NULL) { 1284 KRL_DBG(("%s: revoked by key SHA256", __func__)); 1285 return SSH_ERR_KEY_REVOKED; 1286 } 1287 1288 /* Next, explicit keys */ 1289 memset(&rb, 0, sizeof(rb)); 1290 if ((r = plain_key_blob(key, &rb.blob, &rb.len)) != 0) 1291 return r; 1292 erb = RB_FIND(revoked_blob_tree, &krl->revoked_keys, &rb); 1293 free(rb.blob); 1294 if (erb != NULL) { 1295 KRL_DBG(("%s: revoked by explicit key", __func__)); 1296 return SSH_ERR_KEY_REVOKED; 1297 } 1298 1299 if (!sshkey_is_cert(key)) 1300 return 0; 1301 1302 /* Check cert revocation for the specified CA */ 1303 if ((r = revoked_certs_for_ca_key(krl, key->cert->signature_key, 1304 &rc, 0)) != 0) 1305 return r; 1306 if (rc != NULL) { 1307 if ((r = is_cert_revoked(key, rc)) != 0) 1308 return r; 1309 } 1310 /* Check cert revocation for the wildcard CA */ 1311 if ((r = revoked_certs_for_ca_key(krl, NULL, &rc, 0)) != 0) 1312 return r; 1313 if (rc != NULL) { 1314 if ((r = is_cert_revoked(key, rc)) != 0) 1315 return r; 1316 } 1317 1318 KRL_DBG(("%s: %llu no match", __func__, key->cert->serial)); 1319 return 0; 1320 } 1321 1322 int 1323 ssh_krl_check_key(struct ssh_krl *krl, const struct sshkey *key) 1324 { 1325 int r; 1326 1327 KRL_DBG(("%s: checking key", __func__)); 1328 if ((r = is_key_revoked(krl, key)) != 0) 1329 return r; 1330 if (sshkey_is_cert(key)) { 1331 debug2("%s: checking CA key", __func__); 1332 if ((r = is_key_revoked(krl, key->cert->signature_key)) != 0) 1333 return r; 1334 } 1335 KRL_DBG(("%s: key okay", __func__)); 1336 return 0; 1337 } 1338 1339 int 1340 ssh_krl_file_contains_key(const char *path, const struct sshkey *key) 1341 { 1342 struct sshbuf *krlbuf = NULL; 1343 struct ssh_krl *krl = NULL; 1344 int oerrno = 0, r, fd; 1345 1346 if (path == NULL) 1347 return 0; 1348 1349 if ((krlbuf = sshbuf_new()) == NULL) 1350 return SSH_ERR_ALLOC_FAIL; 1351 if ((fd = open(path, O_RDONLY)) == -1) { 1352 r = SSH_ERR_SYSTEM_ERROR; 1353 oerrno = errno; 1354 goto out; 1355 } 1356 if ((r = sshkey_load_file(fd, krlbuf)) != 0) { 1357 oerrno = errno; 1358 goto out; 1359 } 1360 if ((r = ssh_krl_from_blob(krlbuf, &krl, NULL, 0)) != 0) 1361 goto out; 1362 debug2("%s: checking KRL %s", __func__, path); 1363 r = ssh_krl_check_key(krl, key); 1364 out: 1365 if (fd != -1) 1366 close(fd); 1367 sshbuf_free(krlbuf); 1368 ssh_krl_free(krl); 1369 if (r != 0) 1370 errno = oerrno; 1371 return r; 1372 } 1373