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 1.47 2020/01/25 23:02:13 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 #include <stdlib.h> 30 31 #include "sshbuf.h" 32 #include "ssherr.h" 33 #include "sshkey.h" 34 #include "authfile.h" 35 #include "misc.h" 36 #include "log.h" 37 #include "digest.h" 38 #include "bitmap.h" 39 40 #include "krl.h" 41 42 /* #define DEBUG_KRL */ 43 #ifdef DEBUG_KRL 44 # define KRL_DBG(x) debug3 x 45 #else 46 # define KRL_DBG(x) 47 #endif 48 49 /* 50 * Trees of revoked serial numbers, key IDs and keys. This allows 51 * quick searching, querying and producing lists in canonical order. 52 */ 53 54 /* Tree of serial numbers. XXX make smarter: really need a real sparse bitmap */ 55 struct revoked_serial { 56 u_int64_t lo, hi; 57 RB_ENTRY(revoked_serial) tree_entry; 58 }; 59 static int serial_cmp(struct revoked_serial *a, struct revoked_serial *b); 60 RB_HEAD(revoked_serial_tree, revoked_serial); 61 RB_GENERATE_STATIC(revoked_serial_tree, revoked_serial, tree_entry, serial_cmp); 62 63 /* Tree of key IDs */ 64 struct revoked_key_id { 65 char *key_id; 66 RB_ENTRY(revoked_key_id) tree_entry; 67 }; 68 static int key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b); 69 RB_HEAD(revoked_key_id_tree, revoked_key_id); 70 RB_GENERATE_STATIC(revoked_key_id_tree, revoked_key_id, tree_entry, key_id_cmp); 71 72 /* Tree of blobs (used for keys and fingerprints) */ 73 struct revoked_blob { 74 u_char *blob; 75 size_t len; 76 RB_ENTRY(revoked_blob) tree_entry; 77 }; 78 static int blob_cmp(struct revoked_blob *a, struct revoked_blob *b); 79 RB_HEAD(revoked_blob_tree, revoked_blob); 80 RB_GENERATE_STATIC(revoked_blob_tree, revoked_blob, tree_entry, blob_cmp); 81 82 /* Tracks revoked certs for a single CA */ 83 struct revoked_certs { 84 struct sshkey *ca_key; 85 struct revoked_serial_tree revoked_serials; 86 struct revoked_key_id_tree revoked_key_ids; 87 TAILQ_ENTRY(revoked_certs) entry; 88 }; 89 TAILQ_HEAD(revoked_certs_list, revoked_certs); 90 91 struct ssh_krl { 92 u_int64_t krl_version; 93 u_int64_t generated_date; 94 u_int64_t flags; 95 char *comment; 96 struct revoked_blob_tree revoked_keys; 97 struct revoked_blob_tree revoked_sha1s; 98 struct revoked_blob_tree revoked_sha256s; 99 struct revoked_certs_list revoked_certs; 100 }; 101 102 /* Return equal if a and b overlap */ 103 static int 104 serial_cmp(struct revoked_serial *a, struct revoked_serial *b) 105 { 106 if (a->hi >= b->lo && a->lo <= b->hi) 107 return 0; 108 return a->lo < b->lo ? -1 : 1; 109 } 110 111 static int 112 key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b) 113 { 114 return strcmp(a->key_id, b->key_id); 115 } 116 117 static int 118 blob_cmp(struct revoked_blob *a, struct revoked_blob *b) 119 { 120 int r; 121 122 if (a->len != b->len) { 123 if ((r = memcmp(a->blob, b->blob, MINIMUM(a->len, b->len))) != 0) 124 return r; 125 return a->len > b->len ? 1 : -1; 126 } else 127 return memcmp(a->blob, b->blob, a->len); 128 } 129 130 struct ssh_krl * 131 ssh_krl_init(void) 132 { 133 struct ssh_krl *krl; 134 135 if ((krl = calloc(1, sizeof(*krl))) == NULL) 136 return NULL; 137 RB_INIT(&krl->revoked_keys); 138 RB_INIT(&krl->revoked_sha1s); 139 RB_INIT(&krl->revoked_sha256s); 140 TAILQ_INIT(&krl->revoked_certs); 141 return krl; 142 } 143 144 static void 145 revoked_certs_free(struct revoked_certs *rc) 146 { 147 struct revoked_serial *rs, *trs; 148 struct revoked_key_id *rki, *trki; 149 150 RB_FOREACH_SAFE(rs, revoked_serial_tree, &rc->revoked_serials, trs) { 151 RB_REMOVE(revoked_serial_tree, &rc->revoked_serials, rs); 152 free(rs); 153 } 154 RB_FOREACH_SAFE(rki, revoked_key_id_tree, &rc->revoked_key_ids, trki) { 155 RB_REMOVE(revoked_key_id_tree, &rc->revoked_key_ids, rki); 156 free(rki->key_id); 157 free(rki); 158 } 159 sshkey_free(rc->ca_key); 160 } 161 162 void 163 ssh_krl_free(struct ssh_krl *krl) 164 { 165 struct revoked_blob *rb, *trb; 166 struct revoked_certs *rc, *trc; 167 168 if (krl == NULL) 169 return; 170 171 free(krl->comment); 172 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_keys, trb) { 173 RB_REMOVE(revoked_blob_tree, &krl->revoked_keys, rb); 174 free(rb->blob); 175 free(rb); 176 } 177 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha1s, trb) { 178 RB_REMOVE(revoked_blob_tree, &krl->revoked_sha1s, rb); 179 free(rb->blob); 180 free(rb); 181 } 182 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha256s, trb) { 183 RB_REMOVE(revoked_blob_tree, &krl->revoked_sha256s, rb); 184 free(rb->blob); 185 free(rb); 186 } 187 TAILQ_FOREACH_SAFE(rc, &krl->revoked_certs, entry, trc) { 188 TAILQ_REMOVE(&krl->revoked_certs, rc, entry); 189 revoked_certs_free(rc); 190 } 191 } 192 193 void 194 ssh_krl_set_version(struct ssh_krl *krl, u_int64_t version) 195 { 196 krl->krl_version = version; 197 } 198 199 int 200 ssh_krl_set_comment(struct ssh_krl *krl, const char *comment) 201 { 202 free(krl->comment); 203 if ((krl->comment = strdup(comment)) == NULL) 204 return SSH_ERR_ALLOC_FAIL; 205 return 0; 206 } 207 208 /* 209 * Find the revoked_certs struct for a CA key. If allow_create is set then 210 * create a new one in the tree if one did not exist already. 211 */ 212 static int 213 revoked_certs_for_ca_key(struct ssh_krl *krl, const struct sshkey *ca_key, 214 struct revoked_certs **rcp, int allow_create) 215 { 216 struct revoked_certs *rc; 217 int r; 218 219 *rcp = NULL; 220 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { 221 if ((ca_key == NULL && rc->ca_key == NULL) || 222 sshkey_equal(rc->ca_key, ca_key)) { 223 *rcp = rc; 224 return 0; 225 } 226 } 227 if (!allow_create) 228 return 0; 229 /* If this CA doesn't exist in the list then add it now */ 230 if ((rc = calloc(1, sizeof(*rc))) == NULL) 231 return SSH_ERR_ALLOC_FAIL; 232 if (ca_key == NULL) 233 rc->ca_key = NULL; 234 else if ((r = sshkey_from_private(ca_key, &rc->ca_key)) != 0) { 235 free(rc); 236 return r; 237 } 238 RB_INIT(&rc->revoked_serials); 239 RB_INIT(&rc->revoked_key_ids); 240 TAILQ_INSERT_TAIL(&krl->revoked_certs, rc, entry); 241 KRL_DBG(("%s: new CA %s", __func__, 242 ca_key == NULL ? "*" : sshkey_type(ca_key))); 243 *rcp = rc; 244 return 0; 245 } 246 247 static int 248 insert_serial_range(struct revoked_serial_tree *rt, u_int64_t lo, u_int64_t hi) 249 { 250 struct revoked_serial rs, *ers, *crs, *irs; 251 252 KRL_DBG(("%s: insert %llu:%llu", __func__, lo, hi)); 253 memset(&rs, 0, sizeof(rs)); 254 rs.lo = lo; 255 rs.hi = hi; 256 ers = RB_NFIND(revoked_serial_tree, rt, &rs); 257 if (ers == NULL || serial_cmp(ers, &rs) != 0) { 258 /* No entry matches. Just insert */ 259 if ((irs = malloc(sizeof(rs))) == NULL) 260 return SSH_ERR_ALLOC_FAIL; 261 memcpy(irs, &rs, sizeof(*irs)); 262 ers = RB_INSERT(revoked_serial_tree, rt, irs); 263 if (ers != NULL) { 264 KRL_DBG(("%s: bad: ers != NULL", __func__)); 265 /* Shouldn't happen */ 266 free(irs); 267 return SSH_ERR_INTERNAL_ERROR; 268 } 269 ers = irs; 270 } else { 271 KRL_DBG(("%s: overlap found %llu:%llu", __func__, 272 ers->lo, ers->hi)); 273 /* 274 * The inserted entry overlaps an existing one. Grow the 275 * existing entry. 276 */ 277 if (ers->lo > lo) 278 ers->lo = lo; 279 if (ers->hi < hi) 280 ers->hi = hi; 281 } 282 283 /* 284 * The inserted or revised range might overlap or abut adjacent ones; 285 * coalesce as necessary. 286 */ 287 288 /* Check predecessors */ 289 while ((crs = RB_PREV(revoked_serial_tree, rt, ers)) != NULL) { 290 KRL_DBG(("%s: pred %llu:%llu", __func__, crs->lo, crs->hi)); 291 if (ers->lo != 0 && crs->hi < ers->lo - 1) 292 break; 293 /* This entry overlaps. */ 294 if (crs->lo < ers->lo) { 295 ers->lo = crs->lo; 296 KRL_DBG(("%s: pred extend %llu:%llu", __func__, 297 ers->lo, ers->hi)); 298 } 299 RB_REMOVE(revoked_serial_tree, rt, crs); 300 free(crs); 301 } 302 /* Check successors */ 303 while ((crs = RB_NEXT(revoked_serial_tree, rt, ers)) != NULL) { 304 KRL_DBG(("%s: succ %llu:%llu", __func__, crs->lo, crs->hi)); 305 if (ers->hi != (u_int64_t)-1 && crs->lo > ers->hi + 1) 306 break; 307 /* This entry overlaps. */ 308 if (crs->hi > ers->hi) { 309 ers->hi = crs->hi; 310 KRL_DBG(("%s: succ extend %llu:%llu", __func__, 311 ers->lo, ers->hi)); 312 } 313 RB_REMOVE(revoked_serial_tree, rt, crs); 314 free(crs); 315 } 316 KRL_DBG(("%s: done, final %llu:%llu", __func__, ers->lo, ers->hi)); 317 return 0; 318 } 319 320 int 321 ssh_krl_revoke_cert_by_serial(struct ssh_krl *krl, const struct sshkey *ca_key, 322 u_int64_t serial) 323 { 324 return ssh_krl_revoke_cert_by_serial_range(krl, ca_key, serial, serial); 325 } 326 327 int 328 ssh_krl_revoke_cert_by_serial_range(struct ssh_krl *krl, 329 const struct sshkey *ca_key, u_int64_t lo, u_int64_t hi) 330 { 331 struct revoked_certs *rc; 332 int r; 333 334 if (lo > hi || lo == 0) 335 return SSH_ERR_INVALID_ARGUMENT; 336 if ((r = revoked_certs_for_ca_key(krl, ca_key, &rc, 1)) != 0) 337 return r; 338 return insert_serial_range(&rc->revoked_serials, lo, hi); 339 } 340 341 int 342 ssh_krl_revoke_cert_by_key_id(struct ssh_krl *krl, const struct sshkey *ca_key, 343 const char *key_id) 344 { 345 struct revoked_key_id *rki, *erki; 346 struct revoked_certs *rc; 347 int r; 348 349 if ((r = revoked_certs_for_ca_key(krl, ca_key, &rc, 1)) != 0) 350 return r; 351 352 KRL_DBG(("%s: revoke %s", __func__, key_id)); 353 if ((rki = calloc(1, sizeof(*rki))) == NULL || 354 (rki->key_id = strdup(key_id)) == NULL) { 355 free(rki); 356 return SSH_ERR_ALLOC_FAIL; 357 } 358 erki = RB_INSERT(revoked_key_id_tree, &rc->revoked_key_ids, rki); 359 if (erki != NULL) { 360 free(rki->key_id); 361 free(rki); 362 } 363 return 0; 364 } 365 366 /* Convert "key" to a public key blob without any certificate information */ 367 static int 368 plain_key_blob(const struct sshkey *key, u_char **blob, size_t *blen) 369 { 370 struct sshkey *kcopy; 371 int r; 372 373 if ((r = sshkey_from_private(key, &kcopy)) != 0) 374 return r; 375 if (sshkey_is_cert(kcopy)) { 376 if ((r = sshkey_drop_cert(kcopy)) != 0) { 377 sshkey_free(kcopy); 378 return r; 379 } 380 } 381 r = sshkey_to_blob(kcopy, blob, blen); 382 sshkey_free(kcopy); 383 return r; 384 } 385 386 /* Revoke a key blob. Ownership of blob is transferred to the tree */ 387 static int 388 revoke_blob(struct revoked_blob_tree *rbt, u_char *blob, size_t len) 389 { 390 struct revoked_blob *rb, *erb; 391 392 if ((rb = calloc(1, sizeof(*rb))) == NULL) 393 return SSH_ERR_ALLOC_FAIL; 394 rb->blob = blob; 395 rb->len = len; 396 erb = RB_INSERT(revoked_blob_tree, rbt, rb); 397 if (erb != NULL) { 398 free(rb->blob); 399 free(rb); 400 } 401 return 0; 402 } 403 404 int 405 ssh_krl_revoke_key_explicit(struct ssh_krl *krl, const struct sshkey *key) 406 { 407 u_char *blob; 408 size_t len; 409 int r; 410 411 debug3("%s: revoke type %s", __func__, sshkey_type(key)); 412 if ((r = plain_key_blob(key, &blob, &len)) != 0) 413 return r; 414 return revoke_blob(&krl->revoked_keys, blob, len); 415 } 416 417 static int 418 revoke_by_hash(struct revoked_blob_tree *target, const u_char *p, size_t len) 419 { 420 u_char *blob; 421 int r; 422 423 /* need to copy hash, as revoke_blob steals ownership */ 424 if ((blob = malloc(len)) == NULL) 425 return SSH_ERR_SYSTEM_ERROR; 426 memcpy(blob, p, len); 427 if ((r = revoke_blob(target, blob, len)) != 0) { 428 free(blob); 429 return r; 430 } 431 return 0; 432 } 433 434 int 435 ssh_krl_revoke_key_sha1(struct ssh_krl *krl, const u_char *p, size_t len) 436 { 437 debug3("%s: revoke by sha1", __func__); 438 if (len != 20) 439 return SSH_ERR_INVALID_FORMAT; 440 return revoke_by_hash(&krl->revoked_sha1s, p, len); 441 } 442 443 int 444 ssh_krl_revoke_key_sha256(struct ssh_krl *krl, const u_char *p, size_t len) 445 { 446 debug3("%s: revoke by sha256", __func__); 447 if (len != 32) 448 return SSH_ERR_INVALID_FORMAT; 449 return revoke_by_hash(&krl->revoked_sha256s, p, len); 450 } 451 452 int 453 ssh_krl_revoke_key(struct ssh_krl *krl, const struct sshkey *key) 454 { 455 /* XXX replace with SHA256? */ 456 if (!sshkey_is_cert(key)) 457 return ssh_krl_revoke_key_explicit(krl, key); 458 459 if (key->cert->serial == 0) { 460 return ssh_krl_revoke_cert_by_key_id(krl, 461 key->cert->signature_key, 462 key->cert->key_id); 463 } else { 464 return ssh_krl_revoke_cert_by_serial(krl, 465 key->cert->signature_key, 466 key->cert->serial); 467 } 468 } 469 470 /* 471 * Select the most compact section type to emit next in a KRL based on 472 * the current section type, the run length of contiguous revoked serial 473 * numbers and the gaps from the last and to the next revoked serial. 474 * Applies a mostly-accurate bit cost model to select the section type 475 * that will minimise the size of the resultant KRL. 476 */ 477 static int 478 choose_next_state(int current_state, u_int64_t contig, int final, 479 u_int64_t last_gap, u_int64_t next_gap, int *force_new_section) 480 { 481 int new_state; 482 u_int64_t cost, cost_list, cost_range, cost_bitmap, cost_bitmap_restart; 483 484 /* 485 * Avoid unsigned overflows. 486 * The limits are high enough to avoid confusing the calculations. 487 */ 488 contig = MINIMUM(contig, 1ULL<<31); 489 last_gap = MINIMUM(last_gap, 1ULL<<31); 490 next_gap = MINIMUM(next_gap, 1ULL<<31); 491 492 /* 493 * Calculate the cost to switch from the current state to candidates. 494 * NB. range sections only ever contain a single range, so their 495 * switching cost is independent of the current_state. 496 */ 497 cost_list = cost_bitmap = cost_bitmap_restart = 0; 498 cost_range = 8; 499 switch (current_state) { 500 case KRL_SECTION_CERT_SERIAL_LIST: 501 cost_bitmap_restart = cost_bitmap = 8 + 64; 502 break; 503 case KRL_SECTION_CERT_SERIAL_BITMAP: 504 cost_list = 8; 505 cost_bitmap_restart = 8 + 64; 506 break; 507 case KRL_SECTION_CERT_SERIAL_RANGE: 508 case 0: 509 cost_bitmap_restart = cost_bitmap = 8 + 64; 510 cost_list = 8; 511 } 512 513 /* Estimate base cost in bits of each section type */ 514 cost_list += 64 * contig + (final ? 0 : 8+64); 515 cost_range += (2 * 64) + (final ? 0 : 8+64); 516 cost_bitmap += last_gap + contig + (final ? 0 : MINIMUM(next_gap, 8+64)); 517 cost_bitmap_restart += contig + (final ? 0 : MINIMUM(next_gap, 8+64)); 518 519 /* Convert to byte costs for actual comparison */ 520 cost_list = (cost_list + 7) / 8; 521 cost_bitmap = (cost_bitmap + 7) / 8; 522 cost_bitmap_restart = (cost_bitmap_restart + 7) / 8; 523 cost_range = (cost_range + 7) / 8; 524 525 /* Now pick the best choice */ 526 *force_new_section = 0; 527 new_state = KRL_SECTION_CERT_SERIAL_BITMAP; 528 cost = cost_bitmap; 529 if (cost_range < cost) { 530 new_state = KRL_SECTION_CERT_SERIAL_RANGE; 531 cost = cost_range; 532 } 533 if (cost_list < cost) { 534 new_state = KRL_SECTION_CERT_SERIAL_LIST; 535 cost = cost_list; 536 } 537 if (cost_bitmap_restart < cost) { 538 new_state = KRL_SECTION_CERT_SERIAL_BITMAP; 539 *force_new_section = 1; 540 cost = cost_bitmap_restart; 541 } 542 KRL_DBG(("%s: contig %llu last_gap %llu next_gap %llu final %d, costs:" 543 "list %llu range %llu bitmap %llu new bitmap %llu, " 544 "selected 0x%02x%s", __func__, (long long unsigned)contig, 545 (long long unsigned)last_gap, (long long unsigned)next_gap, final, 546 (long long unsigned)cost_list, (long long unsigned)cost_range, 547 (long long unsigned)cost_bitmap, 548 (long long unsigned)cost_bitmap_restart, new_state, 549 *force_new_section ? " restart" : "")); 550 return new_state; 551 } 552 553 static int 554 put_bitmap(struct sshbuf *buf, struct bitmap *bitmap) 555 { 556 size_t len; 557 u_char *blob; 558 int r; 559 560 len = bitmap_nbytes(bitmap); 561 if ((blob = malloc(len)) == NULL) 562 return SSH_ERR_ALLOC_FAIL; 563 if (bitmap_to_string(bitmap, blob, len) != 0) { 564 free(blob); 565 return SSH_ERR_INTERNAL_ERROR; 566 } 567 r = sshbuf_put_bignum2_bytes(buf, blob, len); 568 free(blob); 569 return r; 570 } 571 572 /* Generate a KRL_SECTION_CERTIFICATES KRL section */ 573 static int 574 revoked_certs_generate(struct revoked_certs *rc, struct sshbuf *buf) 575 { 576 int final, force_new_sect, r = SSH_ERR_INTERNAL_ERROR; 577 u_int64_t i, contig, gap, last = 0, bitmap_start = 0; 578 struct revoked_serial *rs, *nrs; 579 struct revoked_key_id *rki; 580 int next_state, state = 0; 581 struct sshbuf *sect; 582 struct bitmap *bitmap = NULL; 583 584 if ((sect = sshbuf_new()) == NULL) 585 return SSH_ERR_ALLOC_FAIL; 586 587 /* Store the header: optional CA scope key, reserved */ 588 if (rc->ca_key == NULL) { 589 if ((r = sshbuf_put_string(buf, NULL, 0)) != 0) 590 goto out; 591 } else { 592 if ((r = sshkey_puts(rc->ca_key, buf)) != 0) 593 goto out; 594 } 595 if ((r = sshbuf_put_string(buf, NULL, 0)) != 0) 596 goto out; 597 598 /* Store the revoked serials. */ 599 for (rs = RB_MIN(revoked_serial_tree, &rc->revoked_serials); 600 rs != NULL; 601 rs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs)) { 602 KRL_DBG(("%s: serial %llu:%llu state 0x%02x", __func__, 603 (long long unsigned)rs->lo, (long long unsigned)rs->hi, 604 state)); 605 606 /* Check contiguous length and gap to next section (if any) */ 607 nrs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs); 608 final = nrs == NULL; 609 gap = nrs == NULL ? 0 : nrs->lo - rs->hi; 610 contig = 1 + (rs->hi - rs->lo); 611 612 /* Choose next state based on these */ 613 next_state = choose_next_state(state, contig, final, 614 state == 0 ? 0 : rs->lo - last, gap, &force_new_sect); 615 616 /* 617 * If the current section is a range section or has a different 618 * type to the next section, then finish it off now. 619 */ 620 if (state != 0 && (force_new_sect || next_state != state || 621 state == KRL_SECTION_CERT_SERIAL_RANGE)) { 622 KRL_DBG(("%s: finish state 0x%02x", __func__, state)); 623 switch (state) { 624 case KRL_SECTION_CERT_SERIAL_LIST: 625 case KRL_SECTION_CERT_SERIAL_RANGE: 626 break; 627 case KRL_SECTION_CERT_SERIAL_BITMAP: 628 if ((r = put_bitmap(sect, bitmap)) != 0) 629 goto out; 630 bitmap_free(bitmap); 631 bitmap = NULL; 632 break; 633 } 634 if ((r = sshbuf_put_u8(buf, state)) != 0 || 635 (r = sshbuf_put_stringb(buf, sect)) != 0) 636 goto out; 637 sshbuf_reset(sect); 638 } 639 640 /* If we are starting a new section then prepare it now */ 641 if (next_state != state || force_new_sect) { 642 KRL_DBG(("%s: start state 0x%02x", __func__, 643 next_state)); 644 state = next_state; 645 sshbuf_reset(sect); 646 switch (state) { 647 case KRL_SECTION_CERT_SERIAL_LIST: 648 case KRL_SECTION_CERT_SERIAL_RANGE: 649 break; 650 case KRL_SECTION_CERT_SERIAL_BITMAP: 651 if ((bitmap = bitmap_new()) == NULL) { 652 r = SSH_ERR_ALLOC_FAIL; 653 goto out; 654 } 655 bitmap_start = rs->lo; 656 if ((r = sshbuf_put_u64(sect, 657 bitmap_start)) != 0) 658 goto out; 659 break; 660 } 661 } 662 663 /* Perform section-specific processing */ 664 switch (state) { 665 case KRL_SECTION_CERT_SERIAL_LIST: 666 for (i = 0; i < contig; i++) { 667 if ((r = sshbuf_put_u64(sect, rs->lo + i)) != 0) 668 goto out; 669 } 670 break; 671 case KRL_SECTION_CERT_SERIAL_RANGE: 672 if ((r = sshbuf_put_u64(sect, rs->lo)) != 0 || 673 (r = sshbuf_put_u64(sect, rs->hi)) != 0) 674 goto out; 675 break; 676 case KRL_SECTION_CERT_SERIAL_BITMAP: 677 if (rs->lo - bitmap_start > INT_MAX) { 678 error("%s: insane bitmap gap", __func__); 679 goto out; 680 } 681 for (i = 0; i < contig; i++) { 682 if (bitmap_set_bit(bitmap, 683 rs->lo + i - bitmap_start) != 0) { 684 r = SSH_ERR_ALLOC_FAIL; 685 goto out; 686 } 687 } 688 break; 689 } 690 last = rs->hi; 691 } 692 /* Flush the remaining section, if any */ 693 if (state != 0) { 694 KRL_DBG(("%s: serial final flush for state 0x%02x", 695 __func__, state)); 696 switch (state) { 697 case KRL_SECTION_CERT_SERIAL_LIST: 698 case KRL_SECTION_CERT_SERIAL_RANGE: 699 break; 700 case KRL_SECTION_CERT_SERIAL_BITMAP: 701 if ((r = put_bitmap(sect, bitmap)) != 0) 702 goto out; 703 bitmap_free(bitmap); 704 bitmap = NULL; 705 break; 706 } 707 if ((r = sshbuf_put_u8(buf, state)) != 0 || 708 (r = sshbuf_put_stringb(buf, sect)) != 0) 709 goto out; 710 } 711 KRL_DBG(("%s: serial done ", __func__)); 712 713 /* Now output a section for any revocations by key ID */ 714 sshbuf_reset(sect); 715 RB_FOREACH(rki, revoked_key_id_tree, &rc->revoked_key_ids) { 716 KRL_DBG(("%s: key ID %s", __func__, rki->key_id)); 717 if ((r = sshbuf_put_cstring(sect, rki->key_id)) != 0) 718 goto out; 719 } 720 if (sshbuf_len(sect) != 0) { 721 if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERT_KEY_ID)) != 0 || 722 (r = sshbuf_put_stringb(buf, sect)) != 0) 723 goto out; 724 } 725 r = 0; 726 out: 727 bitmap_free(bitmap); 728 sshbuf_free(sect); 729 return r; 730 } 731 732 int 733 ssh_krl_to_blob(struct ssh_krl *krl, struct sshbuf *buf, 734 struct sshkey **sign_keys, u_int nsign_keys) 735 { 736 int r = SSH_ERR_INTERNAL_ERROR; 737 struct revoked_certs *rc; 738 struct revoked_blob *rb; 739 struct sshbuf *sect; 740 u_char *sblob = NULL; 741 size_t slen, i; 742 743 if (krl->generated_date == 0) 744 krl->generated_date = time(NULL); 745 746 if ((sect = sshbuf_new()) == NULL) 747 return SSH_ERR_ALLOC_FAIL; 748 749 /* Store the header */ 750 if ((r = sshbuf_put(buf, KRL_MAGIC, sizeof(KRL_MAGIC) - 1)) != 0 || 751 (r = sshbuf_put_u32(buf, KRL_FORMAT_VERSION)) != 0 || 752 (r = sshbuf_put_u64(buf, krl->krl_version)) != 0 || 753 (r = sshbuf_put_u64(buf, krl->generated_date)) != 0 || 754 (r = sshbuf_put_u64(buf, krl->flags)) != 0 || 755 (r = sshbuf_put_string(buf, NULL, 0)) != 0 || 756 (r = sshbuf_put_cstring(buf, krl->comment)) != 0) 757 goto out; 758 759 /* Store sections for revoked certificates */ 760 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { 761 sshbuf_reset(sect); 762 if ((r = revoked_certs_generate(rc, sect)) != 0) 763 goto out; 764 if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERTIFICATES)) != 0 || 765 (r = sshbuf_put_stringb(buf, sect)) != 0) 766 goto out; 767 } 768 769 /* Finally, output sections for revocations by public key/hash */ 770 sshbuf_reset(sect); 771 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_keys) { 772 KRL_DBG(("%s: key len %zu ", __func__, rb->len)); 773 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 774 goto out; 775 } 776 if (sshbuf_len(sect) != 0) { 777 if ((r = sshbuf_put_u8(buf, KRL_SECTION_EXPLICIT_KEY)) != 0 || 778 (r = sshbuf_put_stringb(buf, sect)) != 0) 779 goto out; 780 } 781 sshbuf_reset(sect); 782 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha1s) { 783 KRL_DBG(("%s: hash len %zu ", __func__, rb->len)); 784 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 785 goto out; 786 } 787 if (sshbuf_len(sect) != 0) { 788 if ((r = sshbuf_put_u8(buf, 789 KRL_SECTION_FINGERPRINT_SHA1)) != 0 || 790 (r = sshbuf_put_stringb(buf, sect)) != 0) 791 goto out; 792 } 793 sshbuf_reset(sect); 794 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha256s) { 795 KRL_DBG(("%s: hash len %zu ", __func__, rb->len)); 796 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 797 goto out; 798 } 799 if (sshbuf_len(sect) != 0) { 800 if ((r = sshbuf_put_u8(buf, 801 KRL_SECTION_FINGERPRINT_SHA256)) != 0 || 802 (r = sshbuf_put_stringb(buf, sect)) != 0) 803 goto out; 804 } 805 806 for (i = 0; i < nsign_keys; i++) { 807 KRL_DBG(("%s: signature key %s", __func__, 808 sshkey_ssh_name(sign_keys[i]))); 809 if ((r = sshbuf_put_u8(buf, KRL_SECTION_SIGNATURE)) != 0 || 810 (r = sshkey_puts(sign_keys[i], buf)) != 0) 811 goto out; 812 813 if ((r = sshkey_sign(sign_keys[i], &sblob, &slen, 814 sshbuf_ptr(buf), sshbuf_len(buf), NULL, NULL, 0)) != 0) 815 goto out; 816 KRL_DBG(("%s: signature sig len %zu", __func__, slen)); 817 if ((r = sshbuf_put_string(buf, sblob, slen)) != 0) 818 goto out; 819 } 820 821 r = 0; 822 out: 823 free(sblob); 824 sshbuf_free(sect); 825 return r; 826 } 827 828 static void 829 format_timestamp(u_int64_t timestamp, char *ts, size_t nts) 830 { 831 time_t t; 832 struct tm *tm; 833 834 t = timestamp; 835 tm = localtime(&t); 836 if (tm == NULL) 837 strlcpy(ts, "<INVALID>", nts); 838 else { 839 *ts = '\0'; 840 strftime(ts, nts, "%Y%m%dT%H%M%S", tm); 841 } 842 } 843 844 static int 845 parse_revoked_certs(struct sshbuf *buf, struct ssh_krl *krl) 846 { 847 int r = SSH_ERR_INTERNAL_ERROR; 848 u_char type; 849 const u_char *blob; 850 size_t blen, nbits; 851 struct sshbuf *subsect = NULL; 852 u_int64_t serial, serial_lo, serial_hi; 853 struct bitmap *bitmap = NULL; 854 char *key_id = NULL; 855 struct sshkey *ca_key = NULL; 856 857 if ((subsect = sshbuf_new()) == NULL) 858 return SSH_ERR_ALLOC_FAIL; 859 860 /* Header: key, reserved */ 861 if ((r = sshbuf_get_string_direct(buf, &blob, &blen)) != 0 || 862 (r = sshbuf_skip_string(buf)) != 0) 863 goto out; 864 if (blen != 0 && (r = sshkey_from_blob(blob, blen, &ca_key)) != 0) 865 goto out; 866 867 while (sshbuf_len(buf) > 0) { 868 sshbuf_free(subsect); 869 subsect = NULL; 870 if ((r = sshbuf_get_u8(buf, &type)) != 0 || 871 (r = sshbuf_froms(buf, &subsect)) != 0) 872 goto out; 873 KRL_DBG(("%s: subsection type 0x%02x", __func__, type)); 874 /* sshbuf_dump(subsect, stderr); */ 875 876 switch (type) { 877 case KRL_SECTION_CERT_SERIAL_LIST: 878 while (sshbuf_len(subsect) > 0) { 879 if ((r = sshbuf_get_u64(subsect, &serial)) != 0) 880 goto out; 881 if ((r = ssh_krl_revoke_cert_by_serial(krl, 882 ca_key, serial)) != 0) 883 goto out; 884 } 885 break; 886 case KRL_SECTION_CERT_SERIAL_RANGE: 887 if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 || 888 (r = sshbuf_get_u64(subsect, &serial_hi)) != 0) 889 goto out; 890 if ((r = ssh_krl_revoke_cert_by_serial_range(krl, 891 ca_key, serial_lo, serial_hi)) != 0) 892 goto out; 893 break; 894 case KRL_SECTION_CERT_SERIAL_BITMAP: 895 if ((bitmap = bitmap_new()) == NULL) { 896 r = SSH_ERR_ALLOC_FAIL; 897 goto out; 898 } 899 if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 || 900 (r = sshbuf_get_bignum2_bytes_direct(subsect, 901 &blob, &blen)) != 0) 902 goto out; 903 if (bitmap_from_string(bitmap, blob, blen) != 0) { 904 r = SSH_ERR_INVALID_FORMAT; 905 goto out; 906 } 907 nbits = bitmap_nbits(bitmap); 908 for (serial = 0; serial < (u_int64_t)nbits; serial++) { 909 if (serial > 0 && serial_lo + serial == 0) { 910 error("%s: bitmap wraps u64", __func__); 911 r = SSH_ERR_INVALID_FORMAT; 912 goto out; 913 } 914 if (!bitmap_test_bit(bitmap, serial)) 915 continue; 916 if ((r = ssh_krl_revoke_cert_by_serial(krl, 917 ca_key, serial_lo + serial)) != 0) 918 goto out; 919 } 920 bitmap_free(bitmap); 921 bitmap = NULL; 922 break; 923 case KRL_SECTION_CERT_KEY_ID: 924 while (sshbuf_len(subsect) > 0) { 925 if ((r = sshbuf_get_cstring(subsect, 926 &key_id, NULL)) != 0) 927 goto out; 928 if ((r = ssh_krl_revoke_cert_by_key_id(krl, 929 ca_key, key_id)) != 0) 930 goto out; 931 free(key_id); 932 key_id = NULL; 933 } 934 break; 935 default: 936 error("Unsupported KRL certificate section %u", type); 937 r = SSH_ERR_INVALID_FORMAT; 938 goto out; 939 } 940 if (sshbuf_len(subsect) > 0) { 941 error("KRL certificate section contains unparsed data"); 942 r = SSH_ERR_INVALID_FORMAT; 943 goto out; 944 } 945 } 946 947 r = 0; 948 out: 949 if (bitmap != NULL) 950 bitmap_free(bitmap); 951 free(key_id); 952 sshkey_free(ca_key); 953 sshbuf_free(subsect); 954 return r; 955 } 956 957 static int 958 blob_section(struct sshbuf *sect, struct revoked_blob_tree *target_tree, 959 size_t expected_len) 960 { 961 u_char *rdata = NULL; 962 size_t rlen = 0; 963 int r; 964 965 while (sshbuf_len(sect) > 0) { 966 if ((r = sshbuf_get_string(sect, &rdata, &rlen)) != 0) 967 return r; 968 if (expected_len != 0 && rlen != expected_len) { 969 error("%s: bad length", __func__); 970 free(rdata); 971 return SSH_ERR_INVALID_FORMAT; 972 } 973 if ((r = revoke_blob(target_tree, rdata, rlen)) != 0) { 974 free(rdata); 975 return r; 976 } 977 } 978 return 0; 979 } 980 981 /* Attempt to parse a KRL, checking its signature (if any) with sign_ca_keys. */ 982 int 983 ssh_krl_from_blob(struct sshbuf *buf, struct ssh_krl **krlp, 984 const struct sshkey **sign_ca_keys, size_t nsign_ca_keys) 985 { 986 struct sshbuf *copy = NULL, *sect = NULL; 987 struct ssh_krl *krl = NULL; 988 char timestamp[64]; 989 int r = SSH_ERR_INTERNAL_ERROR, sig_seen; 990 struct sshkey *key = NULL, **ca_used = NULL, **tmp_ca_used; 991 u_char type; 992 const u_char *blob; 993 size_t i, j, sig_off, sects_off, blen, nca_used; 994 u_int format_version; 995 996 nca_used = 0; 997 *krlp = NULL; 998 if (sshbuf_len(buf) < sizeof(KRL_MAGIC) - 1 || 999 memcmp(sshbuf_ptr(buf), KRL_MAGIC, sizeof(KRL_MAGIC) - 1) != 0) { 1000 debug3("%s: not a KRL", __func__); 1001 return SSH_ERR_KRL_BAD_MAGIC; 1002 } 1003 1004 /* Take a copy of the KRL buffer so we can verify its signature later */ 1005 if ((copy = sshbuf_fromb(buf)) == NULL) { 1006 r = SSH_ERR_ALLOC_FAIL; 1007 goto out; 1008 } 1009 if ((r = sshbuf_consume(copy, sizeof(KRL_MAGIC) - 1)) != 0) 1010 goto out; 1011 1012 if ((krl = ssh_krl_init()) == NULL) { 1013 error("%s: alloc failed", __func__); 1014 goto out; 1015 } 1016 1017 if ((r = sshbuf_get_u32(copy, &format_version)) != 0) 1018 goto out; 1019 if (format_version != KRL_FORMAT_VERSION) { 1020 r = SSH_ERR_INVALID_FORMAT; 1021 goto out; 1022 } 1023 if ((r = sshbuf_get_u64(copy, &krl->krl_version)) != 0 || 1024 (r = sshbuf_get_u64(copy, &krl->generated_date)) != 0 || 1025 (r = sshbuf_get_u64(copy, &krl->flags)) != 0 || 1026 (r = sshbuf_skip_string(copy)) != 0 || 1027 (r = sshbuf_get_cstring(copy, &krl->comment, NULL)) != 0) 1028 goto out; 1029 1030 format_timestamp(krl->generated_date, timestamp, sizeof(timestamp)); 1031 debug("KRL version %llu generated at %s%s%s", 1032 (long long unsigned)krl->krl_version, timestamp, 1033 *krl->comment ? ": " : "", krl->comment); 1034 1035 /* 1036 * 1st pass: verify signatures, if any. This is done to avoid 1037 * detailed parsing of data whose provenance is unverified. 1038 */ 1039 sig_seen = 0; 1040 if (sshbuf_len(buf) < sshbuf_len(copy)) { 1041 /* Shouldn't happen */ 1042 r = SSH_ERR_INTERNAL_ERROR; 1043 goto out; 1044 } 1045 sects_off = sshbuf_len(buf) - sshbuf_len(copy); 1046 while (sshbuf_len(copy) > 0) { 1047 if ((r = sshbuf_get_u8(copy, &type)) != 0 || 1048 (r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0) 1049 goto out; 1050 KRL_DBG(("%s: first pass, section 0x%02x", __func__, type)); 1051 if (type != KRL_SECTION_SIGNATURE) { 1052 if (sig_seen) { 1053 error("KRL contains non-signature section " 1054 "after signature"); 1055 r = SSH_ERR_INVALID_FORMAT; 1056 goto out; 1057 } 1058 /* Not interested for now. */ 1059 continue; 1060 } 1061 sig_seen = 1; 1062 /* First string component is the signing key */ 1063 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 1064 r = SSH_ERR_INVALID_FORMAT; 1065 goto out; 1066 } 1067 if (sshbuf_len(buf) < sshbuf_len(copy)) { 1068 /* Shouldn't happen */ 1069 r = SSH_ERR_INTERNAL_ERROR; 1070 goto out; 1071 } 1072 sig_off = sshbuf_len(buf) - sshbuf_len(copy); 1073 /* Second string component is the signature itself */ 1074 if ((r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0) { 1075 r = SSH_ERR_INVALID_FORMAT; 1076 goto out; 1077 } 1078 /* Check signature over entire KRL up to this point */ 1079 if ((r = sshkey_verify(key, blob, blen, 1080 sshbuf_ptr(buf), sig_off, NULL, 0, NULL)) != 0) 1081 goto out; 1082 /* Check if this key has already signed this KRL */ 1083 for (i = 0; i < nca_used; i++) { 1084 if (sshkey_equal(ca_used[i], key)) { 1085 error("KRL signed more than once with " 1086 "the same key"); 1087 r = SSH_ERR_INVALID_FORMAT; 1088 goto out; 1089 } 1090 } 1091 /* Record keys used to sign the KRL */ 1092 tmp_ca_used = recallocarray(ca_used, nca_used, nca_used + 1, 1093 sizeof(*ca_used)); 1094 if (tmp_ca_used == NULL) { 1095 r = SSH_ERR_ALLOC_FAIL; 1096 goto out; 1097 } 1098 ca_used = tmp_ca_used; 1099 ca_used[nca_used++] = key; 1100 key = NULL; 1101 } 1102 1103 if (sshbuf_len(copy) != 0) { 1104 /* Shouldn't happen */ 1105 r = SSH_ERR_INTERNAL_ERROR; 1106 goto out; 1107 } 1108 1109 /* 1110 * 2nd pass: parse and load the KRL, skipping the header to the point 1111 * where the section start. 1112 */ 1113 sshbuf_free(copy); 1114 if ((copy = sshbuf_fromb(buf)) == NULL) { 1115 r = SSH_ERR_ALLOC_FAIL; 1116 goto out; 1117 } 1118 if ((r = sshbuf_consume(copy, sects_off)) != 0) 1119 goto out; 1120 while (sshbuf_len(copy) > 0) { 1121 sshbuf_free(sect); 1122 sect = NULL; 1123 if ((r = sshbuf_get_u8(copy, &type)) != 0 || 1124 (r = sshbuf_froms(copy, §)) != 0) 1125 goto out; 1126 KRL_DBG(("%s: second pass, section 0x%02x", __func__, type)); 1127 1128 switch (type) { 1129 case KRL_SECTION_CERTIFICATES: 1130 if ((r = parse_revoked_certs(sect, krl)) != 0) 1131 goto out; 1132 break; 1133 case KRL_SECTION_EXPLICIT_KEY: 1134 if ((r = blob_section(sect, 1135 &krl->revoked_keys, 0)) != 0) 1136 goto out; 1137 break; 1138 case KRL_SECTION_FINGERPRINT_SHA1: 1139 if ((r = blob_section(sect, 1140 &krl->revoked_sha1s, 20)) != 0) 1141 goto out; 1142 break; 1143 case KRL_SECTION_FINGERPRINT_SHA256: 1144 if ((r = blob_section(sect, 1145 &krl->revoked_sha256s, 32)) != 0) 1146 goto out; 1147 break; 1148 case KRL_SECTION_SIGNATURE: 1149 /* Handled above, but still need to stay in synch */ 1150 sshbuf_free(sect); 1151 sect = NULL; 1152 if ((r = sshbuf_skip_string(copy)) != 0) 1153 goto out; 1154 break; 1155 default: 1156 error("Unsupported KRL section %u", type); 1157 r = SSH_ERR_INVALID_FORMAT; 1158 goto out; 1159 } 1160 if (sect != NULL && sshbuf_len(sect) > 0) { 1161 error("KRL section contains unparsed data"); 1162 r = SSH_ERR_INVALID_FORMAT; 1163 goto out; 1164 } 1165 } 1166 1167 /* Check that the key(s) used to sign the KRL weren't revoked */ 1168 sig_seen = 0; 1169 for (i = 0; i < nca_used; i++) { 1170 if (ssh_krl_check_key(krl, ca_used[i]) == 0) 1171 sig_seen = 1; 1172 else { 1173 sshkey_free(ca_used[i]); 1174 ca_used[i] = NULL; 1175 } 1176 } 1177 if (nca_used && !sig_seen) { 1178 error("All keys used to sign KRL were revoked"); 1179 r = SSH_ERR_KEY_REVOKED; 1180 goto out; 1181 } 1182 1183 /* If we have CA keys, then verify that one was used to sign the KRL */ 1184 if (sig_seen && nsign_ca_keys != 0) { 1185 sig_seen = 0; 1186 for (i = 0; !sig_seen && i < nsign_ca_keys; i++) { 1187 for (j = 0; j < nca_used; j++) { 1188 if (ca_used[j] == NULL) 1189 continue; 1190 if (sshkey_equal(ca_used[j], sign_ca_keys[i])) { 1191 sig_seen = 1; 1192 break; 1193 } 1194 } 1195 } 1196 if (!sig_seen) { 1197 r = SSH_ERR_SIGNATURE_INVALID; 1198 error("KRL not signed with any trusted key"); 1199 goto out; 1200 } 1201 } 1202 1203 *krlp = krl; 1204 r = 0; 1205 out: 1206 if (r != 0) 1207 ssh_krl_free(krl); 1208 for (i = 0; i < nca_used; i++) 1209 sshkey_free(ca_used[i]); 1210 free(ca_used); 1211 sshkey_free(key); 1212 sshbuf_free(copy); 1213 sshbuf_free(sect); 1214 return r; 1215 } 1216 1217 /* Checks certificate serial number and key ID revocation */ 1218 static int 1219 is_cert_revoked(const struct sshkey *key, struct revoked_certs *rc) 1220 { 1221 struct revoked_serial rs, *ers; 1222 struct revoked_key_id rki, *erki; 1223 1224 /* Check revocation by cert key ID */ 1225 memset(&rki, 0, sizeof(rki)); 1226 rki.key_id = key->cert->key_id; 1227 erki = RB_FIND(revoked_key_id_tree, &rc->revoked_key_ids, &rki); 1228 if (erki != NULL) { 1229 KRL_DBG(("%s: revoked by key ID", __func__)); 1230 return SSH_ERR_KEY_REVOKED; 1231 } 1232 1233 /* 1234 * Zero serials numbers are ignored (it's the default when the 1235 * CA doesn't specify one). 1236 */ 1237 if (key->cert->serial == 0) 1238 return 0; 1239 1240 memset(&rs, 0, sizeof(rs)); 1241 rs.lo = rs.hi = key->cert->serial; 1242 ers = RB_FIND(revoked_serial_tree, &rc->revoked_serials, &rs); 1243 if (ers != NULL) { 1244 KRL_DBG(("%s: revoked serial %llu matched %llu:%llu", __func__, 1245 key->cert->serial, ers->lo, ers->hi)); 1246 return SSH_ERR_KEY_REVOKED; 1247 } 1248 return 0; 1249 } 1250 1251 /* Checks whether a given key/cert is revoked. Does not check its CA */ 1252 static int 1253 is_key_revoked(struct ssh_krl *krl, const struct sshkey *key) 1254 { 1255 struct revoked_blob rb, *erb; 1256 struct revoked_certs *rc; 1257 int r; 1258 1259 /* Check explicitly revoked hashes first */ 1260 memset(&rb, 0, sizeof(rb)); 1261 if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA1, 1262 &rb.blob, &rb.len)) != 0) 1263 return r; 1264 erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha1s, &rb); 1265 free(rb.blob); 1266 if (erb != NULL) { 1267 KRL_DBG(("%s: revoked by key SHA1", __func__)); 1268 return SSH_ERR_KEY_REVOKED; 1269 } 1270 memset(&rb, 0, sizeof(rb)); 1271 if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA256, 1272 &rb.blob, &rb.len)) != 0) 1273 return r; 1274 erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha256s, &rb); 1275 free(rb.blob); 1276 if (erb != NULL) { 1277 KRL_DBG(("%s: revoked by key SHA256", __func__)); 1278 return SSH_ERR_KEY_REVOKED; 1279 } 1280 1281 /* Next, explicit keys */ 1282 memset(&rb, 0, sizeof(rb)); 1283 if ((r = plain_key_blob(key, &rb.blob, &rb.len)) != 0) 1284 return r; 1285 erb = RB_FIND(revoked_blob_tree, &krl->revoked_keys, &rb); 1286 free(rb.blob); 1287 if (erb != NULL) { 1288 KRL_DBG(("%s: revoked by explicit key", __func__)); 1289 return SSH_ERR_KEY_REVOKED; 1290 } 1291 1292 if (!sshkey_is_cert(key)) 1293 return 0; 1294 1295 /* Check cert revocation for the specified CA */ 1296 if ((r = revoked_certs_for_ca_key(krl, key->cert->signature_key, 1297 &rc, 0)) != 0) 1298 return r; 1299 if (rc != NULL) { 1300 if ((r = is_cert_revoked(key, rc)) != 0) 1301 return r; 1302 } 1303 /* Check cert revocation for the wildcard CA */ 1304 if ((r = revoked_certs_for_ca_key(krl, NULL, &rc, 0)) != 0) 1305 return r; 1306 if (rc != NULL) { 1307 if ((r = is_cert_revoked(key, rc)) != 0) 1308 return r; 1309 } 1310 1311 KRL_DBG(("%s: %llu no match", __func__, key->cert->serial)); 1312 return 0; 1313 } 1314 1315 int 1316 ssh_krl_check_key(struct ssh_krl *krl, const struct sshkey *key) 1317 { 1318 int r; 1319 1320 KRL_DBG(("%s: checking key", __func__)); 1321 if ((r = is_key_revoked(krl, key)) != 0) 1322 return r; 1323 if (sshkey_is_cert(key)) { 1324 debug2("%s: checking CA key", __func__); 1325 if ((r = is_key_revoked(krl, key->cert->signature_key)) != 0) 1326 return r; 1327 } 1328 KRL_DBG(("%s: key okay", __func__)); 1329 return 0; 1330 } 1331 1332 int 1333 ssh_krl_file_contains_key(const char *path, const struct sshkey *key) 1334 { 1335 struct sshbuf *krlbuf = NULL; 1336 struct ssh_krl *krl = NULL; 1337 int oerrno = 0, r; 1338 1339 if (path == NULL) 1340 return 0; 1341 if ((r = sshbuf_load_file(path, &krlbuf)) != 0) { 1342 oerrno = errno; 1343 goto out; 1344 } 1345 if ((r = ssh_krl_from_blob(krlbuf, &krl, NULL, 0)) != 0) 1346 goto out; 1347 debug2("%s: checking KRL %s", __func__, path); 1348 r = ssh_krl_check_key(krl, key); 1349 out: 1350 sshbuf_free(krlbuf); 1351 ssh_krl_free(krl); 1352 if (r != 0) 1353 errno = oerrno; 1354 return r; 1355 } 1356