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 1.54 2022/04/28 02:53:31 djm Exp $ */ 18 19 #include "includes.h" 20 21 #include <sys/types.h> 22 #include <openbsd-compat/sys-tree.h> 23 #include <openbsd-compat/sys-queue.h> 24 25 #include <errno.h> 26 #include <fcntl.h> 27 #include <limits.h> 28 #include <stdlib.h> 29 #include <string.h> 30 #include <time.h> 31 #include <unistd.h> 32 33 #include "sshbuf.h" 34 #include "ssherr.h" 35 #include "sshkey.h" 36 #include "authfile.h" 37 #include "misc.h" 38 #include "log.h" 39 #include "digest.h" 40 #include "bitmap.h" 41 #include "utf8.h" 42 43 #include "krl.h" 44 45 /* #define DEBUG_KRL */ 46 #ifdef DEBUG_KRL 47 # define KRL_DBG(x) debug3_f x 48 #else 49 # define KRL_DBG(x) 50 #endif 51 52 /* 53 * Trees of revoked serial numbers, key IDs and keys. This allows 54 * quick searching, querying and producing lists in canonical order. 55 */ 56 57 /* Tree of serial numbers. XXX make smarter: really need a real sparse bitmap */ 58 struct revoked_serial { 59 u_int64_t lo, hi; 60 RB_ENTRY(revoked_serial) tree_entry; 61 }; 62 static int serial_cmp(struct revoked_serial *a, struct revoked_serial *b); 63 RB_HEAD(revoked_serial_tree, revoked_serial); 64 RB_GENERATE_STATIC(revoked_serial_tree, revoked_serial, tree_entry, serial_cmp) 65 66 /* Tree of key IDs */ 67 struct revoked_key_id { 68 char *key_id; 69 RB_ENTRY(revoked_key_id) tree_entry; 70 }; 71 static int key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b); 72 RB_HEAD(revoked_key_id_tree, revoked_key_id); 73 RB_GENERATE_STATIC(revoked_key_id_tree, revoked_key_id, tree_entry, key_id_cmp) 74 75 /* Tree of blobs (used for keys and fingerprints) */ 76 struct revoked_blob { 77 u_char *blob; 78 size_t len; 79 RB_ENTRY(revoked_blob) tree_entry; 80 }; 81 static int blob_cmp(struct revoked_blob *a, struct revoked_blob *b); 82 RB_HEAD(revoked_blob_tree, revoked_blob); 83 RB_GENERATE_STATIC(revoked_blob_tree, revoked_blob, tree_entry, blob_cmp) 84 85 /* Tracks revoked certs for a single CA */ 86 struct revoked_certs { 87 struct sshkey *ca_key; 88 struct revoked_serial_tree revoked_serials; 89 struct revoked_key_id_tree revoked_key_ids; 90 TAILQ_ENTRY(revoked_certs) entry; 91 }; 92 TAILQ_HEAD(revoked_certs_list, revoked_certs); 93 94 struct ssh_krl { 95 u_int64_t krl_version; 96 u_int64_t generated_date; 97 u_int64_t flags; 98 char *comment; 99 struct revoked_blob_tree revoked_keys; 100 struct revoked_blob_tree revoked_sha1s; 101 struct revoked_blob_tree revoked_sha256s; 102 struct revoked_certs_list revoked_certs; 103 }; 104 105 /* Return equal if a and b overlap */ 106 static int 107 serial_cmp(struct revoked_serial *a, struct revoked_serial *b) 108 { 109 if (a->hi >= b->lo && a->lo <= b->hi) 110 return 0; 111 return a->lo < b->lo ? -1 : 1; 112 } 113 114 static int 115 key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b) 116 { 117 return strcmp(a->key_id, b->key_id); 118 } 119 120 static int 121 blob_cmp(struct revoked_blob *a, struct revoked_blob *b) 122 { 123 int r; 124 125 if (a->len != b->len) { 126 if ((r = memcmp(a->blob, b->blob, MINIMUM(a->len, b->len))) != 0) 127 return r; 128 return a->len > b->len ? 1 : -1; 129 } else 130 return memcmp(a->blob, b->blob, a->len); 131 } 132 133 struct ssh_krl * 134 ssh_krl_init(void) 135 { 136 struct ssh_krl *krl; 137 138 if ((krl = calloc(1, sizeof(*krl))) == NULL) 139 return NULL; 140 RB_INIT(&krl->revoked_keys); 141 RB_INIT(&krl->revoked_sha1s); 142 RB_INIT(&krl->revoked_sha256s); 143 TAILQ_INIT(&krl->revoked_certs); 144 return krl; 145 } 146 147 static void 148 revoked_certs_free(struct revoked_certs *rc) 149 { 150 struct revoked_serial *rs, *trs; 151 struct revoked_key_id *rki, *trki; 152 153 RB_FOREACH_SAFE(rs, revoked_serial_tree, &rc->revoked_serials, trs) { 154 RB_REMOVE(revoked_serial_tree, &rc->revoked_serials, rs); 155 free(rs); 156 } 157 RB_FOREACH_SAFE(rki, revoked_key_id_tree, &rc->revoked_key_ids, trki) { 158 RB_REMOVE(revoked_key_id_tree, &rc->revoked_key_ids, rki); 159 free(rki->key_id); 160 free(rki); 161 } 162 sshkey_free(rc->ca_key); 163 } 164 165 void 166 ssh_krl_free(struct ssh_krl *krl) 167 { 168 struct revoked_blob *rb, *trb; 169 struct revoked_certs *rc, *trc; 170 171 if (krl == NULL) 172 return; 173 174 free(krl->comment); 175 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_keys, trb) { 176 RB_REMOVE(revoked_blob_tree, &krl->revoked_keys, rb); 177 free(rb->blob); 178 free(rb); 179 } 180 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha1s, trb) { 181 RB_REMOVE(revoked_blob_tree, &krl->revoked_sha1s, rb); 182 free(rb->blob); 183 free(rb); 184 } 185 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha256s, trb) { 186 RB_REMOVE(revoked_blob_tree, &krl->revoked_sha256s, rb); 187 free(rb->blob); 188 free(rb); 189 } 190 TAILQ_FOREACH_SAFE(rc, &krl->revoked_certs, entry, trc) { 191 TAILQ_REMOVE(&krl->revoked_certs, rc, entry); 192 revoked_certs_free(rc); 193 } 194 } 195 196 void 197 ssh_krl_set_version(struct ssh_krl *krl, u_int64_t version) 198 { 199 krl->krl_version = version; 200 } 201 202 int 203 ssh_krl_set_comment(struct ssh_krl *krl, const char *comment) 204 { 205 free(krl->comment); 206 if ((krl->comment = strdup(comment)) == NULL) 207 return SSH_ERR_ALLOC_FAIL; 208 return 0; 209 } 210 211 /* 212 * Find the revoked_certs struct for a CA key. If allow_create is set then 213 * create a new one in the tree if one did not exist already. 214 */ 215 static int 216 revoked_certs_for_ca_key(struct ssh_krl *krl, const struct sshkey *ca_key, 217 struct revoked_certs **rcp, int allow_create) 218 { 219 struct revoked_certs *rc; 220 int r; 221 222 *rcp = NULL; 223 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { 224 if ((ca_key == NULL && rc->ca_key == NULL) || 225 sshkey_equal(rc->ca_key, ca_key)) { 226 *rcp = rc; 227 return 0; 228 } 229 } 230 if (!allow_create) 231 return 0; 232 /* If this CA doesn't exist in the list then add it now */ 233 if ((rc = calloc(1, sizeof(*rc))) == NULL) 234 return SSH_ERR_ALLOC_FAIL; 235 if (ca_key == NULL) 236 rc->ca_key = NULL; 237 else if ((r = sshkey_from_private(ca_key, &rc->ca_key)) != 0) { 238 free(rc); 239 return r; 240 } 241 RB_INIT(&rc->revoked_serials); 242 RB_INIT(&rc->revoked_key_ids); 243 TAILQ_INSERT_TAIL(&krl->revoked_certs, rc, entry); 244 KRL_DBG(("new CA %s", ca_key == NULL ? "*" : sshkey_type(ca_key))); 245 *rcp = rc; 246 return 0; 247 } 248 249 static int 250 insert_serial_range(struct revoked_serial_tree *rt, u_int64_t lo, u_int64_t hi) 251 { 252 struct revoked_serial rs, *ers, *crs, *irs; 253 254 KRL_DBG(("insert %llu:%llu", lo, hi)); 255 memset(&rs, 0, sizeof(rs)); 256 rs.lo = lo; 257 rs.hi = hi; 258 ers = RB_NFIND(revoked_serial_tree, rt, &rs); 259 if (ers == NULL || serial_cmp(ers, &rs) != 0) { 260 /* No entry matches. Just insert */ 261 if ((irs = malloc(sizeof(rs))) == NULL) 262 return SSH_ERR_ALLOC_FAIL; 263 memcpy(irs, &rs, sizeof(*irs)); 264 ers = RB_INSERT(revoked_serial_tree, rt, irs); 265 if (ers != NULL) { 266 KRL_DBG(("bad: ers != NULL")); 267 /* Shouldn't happen */ 268 free(irs); 269 return SSH_ERR_INTERNAL_ERROR; 270 } 271 ers = irs; 272 } else { 273 KRL_DBG(("overlap found %llu:%llu", ers->lo, ers->hi)); 274 /* 275 * The inserted entry overlaps an existing one. Grow the 276 * existing entry. 277 */ 278 if (ers->lo > lo) 279 ers->lo = lo; 280 if (ers->hi < hi) 281 ers->hi = hi; 282 } 283 284 /* 285 * The inserted or revised range might overlap or abut adjacent ones; 286 * coalesce as necessary. 287 */ 288 289 /* Check predecessors */ 290 while ((crs = RB_PREV(revoked_serial_tree, rt, ers)) != NULL) { 291 KRL_DBG(("pred %llu:%llu", crs->lo, crs->hi)); 292 if (ers->lo != 0 && crs->hi < ers->lo - 1) 293 break; 294 /* This entry overlaps. */ 295 if (crs->lo < ers->lo) { 296 ers->lo = crs->lo; 297 KRL_DBG(("pred extend %llu:%llu", 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(("succ %llu:%llu", 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(("succ extend %llu:%llu", ers->lo, ers->hi)); 311 } 312 RB_REMOVE(revoked_serial_tree, rt, crs); 313 free(crs); 314 } 315 KRL_DBG(("done, final %llu:%llu", 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(("revoke %s", 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_f("revoke type %s", 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_f("revoke by sha1"); 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_f("revoke by sha256"); 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(("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", (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(("serial %llu:%llu state 0x%02x", 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(("finish state 0x%02x", 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(("start state 0x%02x", 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_f("insane bitmap gap"); 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(("serial final flush for state 0x%02x", state)); 694 switch (state) { 695 case KRL_SECTION_CERT_SERIAL_LIST: 696 case KRL_SECTION_CERT_SERIAL_RANGE: 697 break; 698 case KRL_SECTION_CERT_SERIAL_BITMAP: 699 if ((r = put_bitmap(sect, bitmap)) != 0) 700 goto out; 701 bitmap_free(bitmap); 702 bitmap = NULL; 703 break; 704 } 705 if ((r = sshbuf_put_u8(buf, state)) != 0 || 706 (r = sshbuf_put_stringb(buf, sect)) != 0) 707 goto out; 708 } 709 KRL_DBG(("serial done ")); 710 711 /* Now output a section for any revocations by key ID */ 712 sshbuf_reset(sect); 713 RB_FOREACH(rki, revoked_key_id_tree, &rc->revoked_key_ids) { 714 KRL_DBG(("key ID %s", rki->key_id)); 715 if ((r = sshbuf_put_cstring(sect, rki->key_id)) != 0) 716 goto out; 717 } 718 if (sshbuf_len(sect) != 0) { 719 if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERT_KEY_ID)) != 0 || 720 (r = sshbuf_put_stringb(buf, sect)) != 0) 721 goto out; 722 } 723 r = 0; 724 out: 725 bitmap_free(bitmap); 726 sshbuf_free(sect); 727 return r; 728 } 729 730 int 731 ssh_krl_to_blob(struct ssh_krl *krl, struct sshbuf *buf, 732 struct sshkey **sign_keys, u_int nsign_keys) 733 { 734 int r = SSH_ERR_INTERNAL_ERROR; 735 struct revoked_certs *rc; 736 struct revoked_blob *rb; 737 struct sshbuf *sect; 738 u_char *sblob = NULL; 739 size_t slen, i; 740 741 if (krl->generated_date == 0) 742 krl->generated_date = time(NULL); 743 744 if ((sect = sshbuf_new()) == NULL) 745 return SSH_ERR_ALLOC_FAIL; 746 747 /* Store the header */ 748 if ((r = sshbuf_put(buf, KRL_MAGIC, sizeof(KRL_MAGIC) - 1)) != 0 || 749 (r = sshbuf_put_u32(buf, KRL_FORMAT_VERSION)) != 0 || 750 (r = sshbuf_put_u64(buf, krl->krl_version)) != 0 || 751 (r = sshbuf_put_u64(buf, krl->generated_date)) != 0 || 752 (r = sshbuf_put_u64(buf, krl->flags)) != 0 || 753 (r = sshbuf_put_string(buf, NULL, 0)) != 0 || 754 (r = sshbuf_put_cstring(buf, krl->comment)) != 0) 755 goto out; 756 757 /* Store sections for revoked certificates */ 758 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { 759 sshbuf_reset(sect); 760 if ((r = revoked_certs_generate(rc, sect)) != 0) 761 goto out; 762 if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERTIFICATES)) != 0 || 763 (r = sshbuf_put_stringb(buf, sect)) != 0) 764 goto out; 765 } 766 767 /* Finally, output sections for revocations by public key/hash */ 768 sshbuf_reset(sect); 769 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_keys) { 770 KRL_DBG(("key len %zu ", rb->len)); 771 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 772 goto out; 773 } 774 if (sshbuf_len(sect) != 0) { 775 if ((r = sshbuf_put_u8(buf, KRL_SECTION_EXPLICIT_KEY)) != 0 || 776 (r = sshbuf_put_stringb(buf, sect)) != 0) 777 goto out; 778 } 779 sshbuf_reset(sect); 780 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha1s) { 781 KRL_DBG(("hash len %zu ", rb->len)); 782 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 783 goto out; 784 } 785 if (sshbuf_len(sect) != 0) { 786 if ((r = sshbuf_put_u8(buf, 787 KRL_SECTION_FINGERPRINT_SHA1)) != 0 || 788 (r = sshbuf_put_stringb(buf, sect)) != 0) 789 goto out; 790 } 791 sshbuf_reset(sect); 792 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha256s) { 793 KRL_DBG(("hash len %zu ", rb->len)); 794 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 795 goto out; 796 } 797 if (sshbuf_len(sect) != 0) { 798 if ((r = sshbuf_put_u8(buf, 799 KRL_SECTION_FINGERPRINT_SHA256)) != 0 || 800 (r = sshbuf_put_stringb(buf, sect)) != 0) 801 goto out; 802 } 803 804 for (i = 0; i < nsign_keys; i++) { 805 KRL_DBG(("sig key %s", sshkey_ssh_name(sign_keys[i]))); 806 if ((r = sshbuf_put_u8(buf, KRL_SECTION_SIGNATURE)) != 0 || 807 (r = sshkey_puts(sign_keys[i], buf)) != 0) 808 goto out; 809 /* XXX support sk-* keys */ 810 if ((r = sshkey_sign(sign_keys[i], &sblob, &slen, 811 sshbuf_ptr(buf), sshbuf_len(buf), NULL, NULL, 812 NULL, 0)) != 0) 813 goto out; 814 KRL_DBG(("signature sig len %zu", slen)); 815 if ((r = sshbuf_put_string(buf, sblob, slen)) != 0) 816 goto out; 817 } 818 819 r = 0; 820 out: 821 free(sblob); 822 sshbuf_free(sect); 823 return r; 824 } 825 826 static void 827 format_timestamp(u_int64_t timestamp, char *ts, size_t nts) 828 { 829 time_t t; 830 struct tm *tm; 831 832 t = timestamp; 833 tm = localtime(&t); 834 if (tm == NULL) 835 strlcpy(ts, "<INVALID>", nts); 836 else { 837 *ts = '\0'; 838 strftime(ts, nts, "%Y%m%dT%H%M%S", tm); 839 } 840 } 841 842 static int 843 parse_revoked_certs(struct sshbuf *buf, struct ssh_krl *krl) 844 { 845 int r = SSH_ERR_INTERNAL_ERROR; 846 u_char type; 847 const u_char *blob; 848 size_t blen, nbits; 849 struct sshbuf *subsect = NULL; 850 u_int64_t serial, serial_lo, serial_hi; 851 struct bitmap *bitmap = NULL; 852 char *key_id = NULL; 853 struct sshkey *ca_key = NULL; 854 855 if ((subsect = sshbuf_new()) == NULL) 856 return SSH_ERR_ALLOC_FAIL; 857 858 /* Header: key, reserved */ 859 if ((r = sshbuf_get_string_direct(buf, &blob, &blen)) != 0 || 860 (r = sshbuf_skip_string(buf)) != 0) 861 goto out; 862 if (blen != 0 && (r = sshkey_from_blob(blob, blen, &ca_key)) != 0) 863 goto out; 864 865 while (sshbuf_len(buf) > 0) { 866 sshbuf_free(subsect); 867 subsect = NULL; 868 if ((r = sshbuf_get_u8(buf, &type)) != 0 || 869 (r = sshbuf_froms(buf, &subsect)) != 0) 870 goto out; 871 KRL_DBG(("subsection type 0x%02x", type)); 872 /* sshbuf_dump(subsect, stderr); */ 873 874 switch (type) { 875 case KRL_SECTION_CERT_SERIAL_LIST: 876 while (sshbuf_len(subsect) > 0) { 877 if ((r = sshbuf_get_u64(subsect, &serial)) != 0) 878 goto out; 879 if ((r = ssh_krl_revoke_cert_by_serial(krl, 880 ca_key, serial)) != 0) 881 goto out; 882 } 883 break; 884 case KRL_SECTION_CERT_SERIAL_RANGE: 885 if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 || 886 (r = sshbuf_get_u64(subsect, &serial_hi)) != 0) 887 goto out; 888 if ((r = ssh_krl_revoke_cert_by_serial_range(krl, 889 ca_key, serial_lo, serial_hi)) != 0) 890 goto out; 891 break; 892 case KRL_SECTION_CERT_SERIAL_BITMAP: 893 if ((bitmap = bitmap_new()) == NULL) { 894 r = SSH_ERR_ALLOC_FAIL; 895 goto out; 896 } 897 if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 || 898 (r = sshbuf_get_bignum2_bytes_direct(subsect, 899 &blob, &blen)) != 0) 900 goto out; 901 if (bitmap_from_string(bitmap, blob, blen) != 0) { 902 r = SSH_ERR_INVALID_FORMAT; 903 goto out; 904 } 905 nbits = bitmap_nbits(bitmap); 906 for (serial = 0; serial < (u_int64_t)nbits; serial++) { 907 if (serial > 0 && serial_lo + serial == 0) { 908 error_f("bitmap wraps u64"); 909 r = SSH_ERR_INVALID_FORMAT; 910 goto out; 911 } 912 if (!bitmap_test_bit(bitmap, serial)) 913 continue; 914 if ((r = ssh_krl_revoke_cert_by_serial(krl, 915 ca_key, serial_lo + serial)) != 0) 916 goto out; 917 } 918 bitmap_free(bitmap); 919 bitmap = NULL; 920 break; 921 case KRL_SECTION_CERT_KEY_ID: 922 while (sshbuf_len(subsect) > 0) { 923 if ((r = sshbuf_get_cstring(subsect, 924 &key_id, NULL)) != 0) 925 goto out; 926 if ((r = ssh_krl_revoke_cert_by_key_id(krl, 927 ca_key, key_id)) != 0) 928 goto out; 929 free(key_id); 930 key_id = NULL; 931 } 932 break; 933 default: 934 error("Unsupported KRL certificate section %u", type); 935 r = SSH_ERR_INVALID_FORMAT; 936 goto out; 937 } 938 if (sshbuf_len(subsect) > 0) { 939 error("KRL certificate section contains unparsed data"); 940 r = SSH_ERR_INVALID_FORMAT; 941 goto out; 942 } 943 } 944 945 r = 0; 946 out: 947 if (bitmap != NULL) 948 bitmap_free(bitmap); 949 free(key_id); 950 sshkey_free(ca_key); 951 sshbuf_free(subsect); 952 return r; 953 } 954 955 static int 956 blob_section(struct sshbuf *sect, struct revoked_blob_tree *target_tree, 957 size_t expected_len) 958 { 959 u_char *rdata = NULL; 960 size_t rlen = 0; 961 int r; 962 963 while (sshbuf_len(sect) > 0) { 964 if ((r = sshbuf_get_string(sect, &rdata, &rlen)) != 0) 965 return r; 966 if (expected_len != 0 && rlen != expected_len) { 967 error_f("bad length"); 968 free(rdata); 969 return SSH_ERR_INVALID_FORMAT; 970 } 971 if ((r = revoke_blob(target_tree, rdata, rlen)) != 0) { 972 free(rdata); 973 return r; 974 } 975 } 976 return 0; 977 } 978 979 /* Attempt to parse a KRL, checking its signature (if any) with sign_ca_keys. */ 980 int 981 ssh_krl_from_blob(struct sshbuf *buf, struct ssh_krl **krlp, 982 const struct sshkey **sign_ca_keys, size_t nsign_ca_keys) 983 { 984 struct sshbuf *copy = NULL, *sect = NULL; 985 struct ssh_krl *krl = NULL; 986 char timestamp[64]; 987 int r = SSH_ERR_INTERNAL_ERROR, sig_seen; 988 struct sshkey *key = NULL, **ca_used = NULL, **tmp_ca_used; 989 u_char type; 990 const u_char *blob; 991 size_t i, j, sig_off, sects_off, blen, nca_used; 992 u_int format_version; 993 994 nca_used = 0; 995 *krlp = NULL; 996 if (sshbuf_len(buf) < sizeof(KRL_MAGIC) - 1 || 997 memcmp(sshbuf_ptr(buf), KRL_MAGIC, sizeof(KRL_MAGIC) - 1) != 0) { 998 debug3_f("not a KRL"); 999 return SSH_ERR_KRL_BAD_MAGIC; 1000 } 1001 1002 /* Take a copy of the KRL buffer so we can verify its signature later */ 1003 if ((copy = sshbuf_fromb(buf)) == NULL) { 1004 r = SSH_ERR_ALLOC_FAIL; 1005 goto out; 1006 } 1007 if ((r = sshbuf_consume(copy, sizeof(KRL_MAGIC) - 1)) != 0) 1008 goto out; 1009 1010 if ((krl = ssh_krl_init()) == NULL) { 1011 error_f("alloc failed"); 1012 goto out; 1013 } 1014 1015 if ((r = sshbuf_get_u32(copy, &format_version)) != 0) 1016 goto out; 1017 if (format_version != KRL_FORMAT_VERSION) { 1018 r = SSH_ERR_INVALID_FORMAT; 1019 goto out; 1020 } 1021 if ((r = sshbuf_get_u64(copy, &krl->krl_version)) != 0 || 1022 (r = sshbuf_get_u64(copy, &krl->generated_date)) != 0 || 1023 (r = sshbuf_get_u64(copy, &krl->flags)) != 0 || 1024 (r = sshbuf_skip_string(copy)) != 0 || 1025 (r = sshbuf_get_cstring(copy, &krl->comment, NULL)) != 0) 1026 goto out; 1027 1028 format_timestamp(krl->generated_date, timestamp, sizeof(timestamp)); 1029 debug("KRL version %llu generated at %s%s%s", 1030 (long long unsigned)krl->krl_version, timestamp, 1031 *krl->comment ? ": " : "", krl->comment); 1032 1033 /* 1034 * 1st pass: verify signatures, if any. This is done to avoid 1035 * detailed parsing of data whose provenance is unverified. 1036 */ 1037 sig_seen = 0; 1038 if (sshbuf_len(buf) < sshbuf_len(copy)) { 1039 /* Shouldn't happen */ 1040 r = SSH_ERR_INTERNAL_ERROR; 1041 goto out; 1042 } 1043 sects_off = sshbuf_len(buf) - sshbuf_len(copy); 1044 while (sshbuf_len(copy) > 0) { 1045 if ((r = sshbuf_get_u8(copy, &type)) != 0 || 1046 (r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0) 1047 goto out; 1048 KRL_DBG(("first pass, section 0x%02x", type)); 1049 if (type != KRL_SECTION_SIGNATURE) { 1050 if (sig_seen) { 1051 error("KRL contains non-signature section " 1052 "after signature"); 1053 r = SSH_ERR_INVALID_FORMAT; 1054 goto out; 1055 } 1056 /* Not interested for now. */ 1057 continue; 1058 } 1059 sig_seen = 1; 1060 /* First string component is the signing key */ 1061 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 1062 r = SSH_ERR_INVALID_FORMAT; 1063 goto out; 1064 } 1065 if (sshbuf_len(buf) < sshbuf_len(copy)) { 1066 /* Shouldn't happen */ 1067 r = SSH_ERR_INTERNAL_ERROR; 1068 goto out; 1069 } 1070 sig_off = sshbuf_len(buf) - sshbuf_len(copy); 1071 /* Second string component is the signature itself */ 1072 if ((r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0) { 1073 r = SSH_ERR_INVALID_FORMAT; 1074 goto out; 1075 } 1076 /* Check signature over entire KRL up to this point */ 1077 if ((r = sshkey_verify(key, blob, blen, 1078 sshbuf_ptr(buf), sig_off, NULL, 0, NULL)) != 0) 1079 goto out; 1080 /* Check if this key has already signed this KRL */ 1081 for (i = 0; i < nca_used; i++) { 1082 if (sshkey_equal(ca_used[i], key)) { 1083 error("KRL signed more than once with " 1084 "the same key"); 1085 r = SSH_ERR_INVALID_FORMAT; 1086 goto out; 1087 } 1088 } 1089 /* Record keys used to sign the KRL */ 1090 tmp_ca_used = recallocarray(ca_used, nca_used, nca_used + 1, 1091 sizeof(*ca_used)); 1092 if (tmp_ca_used == NULL) { 1093 r = SSH_ERR_ALLOC_FAIL; 1094 goto out; 1095 } 1096 ca_used = tmp_ca_used; 1097 ca_used[nca_used++] = key; 1098 key = NULL; 1099 } 1100 1101 if (sshbuf_len(copy) != 0) { 1102 /* Shouldn't happen */ 1103 r = SSH_ERR_INTERNAL_ERROR; 1104 goto out; 1105 } 1106 1107 /* 1108 * 2nd pass: parse and load the KRL, skipping the header to the point 1109 * where the section start. 1110 */ 1111 sshbuf_free(copy); 1112 if ((copy = sshbuf_fromb(buf)) == NULL) { 1113 r = SSH_ERR_ALLOC_FAIL; 1114 goto out; 1115 } 1116 if ((r = sshbuf_consume(copy, sects_off)) != 0) 1117 goto out; 1118 while (sshbuf_len(copy) > 0) { 1119 sshbuf_free(sect); 1120 sect = NULL; 1121 if ((r = sshbuf_get_u8(copy, &type)) != 0 || 1122 (r = sshbuf_froms(copy, §)) != 0) 1123 goto out; 1124 KRL_DBG(("second pass, section 0x%02x", type)); 1125 1126 switch (type) { 1127 case KRL_SECTION_CERTIFICATES: 1128 if ((r = parse_revoked_certs(sect, krl)) != 0) 1129 goto out; 1130 break; 1131 case KRL_SECTION_EXPLICIT_KEY: 1132 if ((r = blob_section(sect, 1133 &krl->revoked_keys, 0)) != 0) 1134 goto out; 1135 break; 1136 case KRL_SECTION_FINGERPRINT_SHA1: 1137 if ((r = blob_section(sect, 1138 &krl->revoked_sha1s, 20)) != 0) 1139 goto out; 1140 break; 1141 case KRL_SECTION_FINGERPRINT_SHA256: 1142 if ((r = blob_section(sect, 1143 &krl->revoked_sha256s, 32)) != 0) 1144 goto out; 1145 break; 1146 case KRL_SECTION_SIGNATURE: 1147 /* Handled above, but still need to stay in synch */ 1148 sshbuf_free(sect); 1149 sect = NULL; 1150 if ((r = sshbuf_skip_string(copy)) != 0) 1151 goto out; 1152 break; 1153 default: 1154 error("Unsupported KRL section %u", type); 1155 r = SSH_ERR_INVALID_FORMAT; 1156 goto out; 1157 } 1158 if (sect != NULL && sshbuf_len(sect) > 0) { 1159 error("KRL section contains unparsed data"); 1160 r = SSH_ERR_INVALID_FORMAT; 1161 goto out; 1162 } 1163 } 1164 1165 /* Check that the key(s) used to sign the KRL weren't revoked */ 1166 sig_seen = 0; 1167 for (i = 0; i < nca_used; i++) { 1168 if (ssh_krl_check_key(krl, ca_used[i]) == 0) 1169 sig_seen = 1; 1170 else { 1171 sshkey_free(ca_used[i]); 1172 ca_used[i] = NULL; 1173 } 1174 } 1175 if (nca_used && !sig_seen) { 1176 error("All keys used to sign KRL were revoked"); 1177 r = SSH_ERR_KEY_REVOKED; 1178 goto out; 1179 } 1180 1181 /* If we have CA keys, then verify that one was used to sign the KRL */ 1182 if (sig_seen && nsign_ca_keys != 0) { 1183 sig_seen = 0; 1184 for (i = 0; !sig_seen && i < nsign_ca_keys; i++) { 1185 for (j = 0; j < nca_used; j++) { 1186 if (ca_used[j] == NULL) 1187 continue; 1188 if (sshkey_equal(ca_used[j], sign_ca_keys[i])) { 1189 sig_seen = 1; 1190 break; 1191 } 1192 } 1193 } 1194 if (!sig_seen) { 1195 r = SSH_ERR_SIGNATURE_INVALID; 1196 error("KRL not signed with any trusted key"); 1197 goto out; 1198 } 1199 } 1200 1201 *krlp = krl; 1202 r = 0; 1203 out: 1204 if (r != 0) 1205 ssh_krl_free(krl); 1206 for (i = 0; i < nca_used; i++) 1207 sshkey_free(ca_used[i]); 1208 free(ca_used); 1209 sshkey_free(key); 1210 sshbuf_free(copy); 1211 sshbuf_free(sect); 1212 return r; 1213 } 1214 1215 /* Checks certificate serial number and key ID revocation */ 1216 static int 1217 is_cert_revoked(const struct sshkey *key, struct revoked_certs *rc) 1218 { 1219 struct revoked_serial rs, *ers; 1220 struct revoked_key_id rki, *erki; 1221 1222 /* Check revocation by cert key ID */ 1223 memset(&rki, 0, sizeof(rki)); 1224 rki.key_id = key->cert->key_id; 1225 erki = RB_FIND(revoked_key_id_tree, &rc->revoked_key_ids, &rki); 1226 if (erki != NULL) { 1227 KRL_DBG(("revoked by key ID")); 1228 return SSH_ERR_KEY_REVOKED; 1229 } 1230 1231 /* 1232 * Zero serials numbers are ignored (it's the default when the 1233 * CA doesn't specify one). 1234 */ 1235 if (key->cert->serial == 0) 1236 return 0; 1237 1238 memset(&rs, 0, sizeof(rs)); 1239 rs.lo = rs.hi = key->cert->serial; 1240 ers = RB_FIND(revoked_serial_tree, &rc->revoked_serials, &rs); 1241 if (ers != NULL) { 1242 KRL_DBG(("revoked serial %llu matched %llu:%llu", 1243 key->cert->serial, ers->lo, ers->hi)); 1244 return SSH_ERR_KEY_REVOKED; 1245 } 1246 return 0; 1247 } 1248 1249 /* Checks whether a given key/cert is revoked. Does not check its CA */ 1250 static int 1251 is_key_revoked(struct ssh_krl *krl, const struct sshkey *key) 1252 { 1253 struct revoked_blob rb, *erb; 1254 struct revoked_certs *rc; 1255 int r; 1256 1257 /* Check explicitly revoked hashes first */ 1258 memset(&rb, 0, sizeof(rb)); 1259 if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA1, 1260 &rb.blob, &rb.len)) != 0) 1261 return r; 1262 erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha1s, &rb); 1263 free(rb.blob); 1264 if (erb != NULL) { 1265 KRL_DBG(("revoked by key SHA1")); 1266 return SSH_ERR_KEY_REVOKED; 1267 } 1268 memset(&rb, 0, sizeof(rb)); 1269 if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA256, 1270 &rb.blob, &rb.len)) != 0) 1271 return r; 1272 erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha256s, &rb); 1273 free(rb.blob); 1274 if (erb != NULL) { 1275 KRL_DBG(("revoked by key SHA256")); 1276 return SSH_ERR_KEY_REVOKED; 1277 } 1278 1279 /* Next, explicit keys */ 1280 memset(&rb, 0, sizeof(rb)); 1281 if ((r = plain_key_blob(key, &rb.blob, &rb.len)) != 0) 1282 return r; 1283 erb = RB_FIND(revoked_blob_tree, &krl->revoked_keys, &rb); 1284 free(rb.blob); 1285 if (erb != NULL) { 1286 KRL_DBG(("revoked by explicit key")); 1287 return SSH_ERR_KEY_REVOKED; 1288 } 1289 1290 if (!sshkey_is_cert(key)) 1291 return 0; 1292 1293 /* Check cert revocation for the specified CA */ 1294 if ((r = revoked_certs_for_ca_key(krl, key->cert->signature_key, 1295 &rc, 0)) != 0) 1296 return r; 1297 if (rc != NULL) { 1298 if ((r = is_cert_revoked(key, rc)) != 0) 1299 return r; 1300 } 1301 /* Check cert revocation for the wildcard CA */ 1302 if ((r = revoked_certs_for_ca_key(krl, NULL, &rc, 0)) != 0) 1303 return r; 1304 if (rc != NULL) { 1305 if ((r = is_cert_revoked(key, rc)) != 0) 1306 return r; 1307 } 1308 1309 KRL_DBG(("%llu no match", key->cert->serial)); 1310 return 0; 1311 } 1312 1313 int 1314 ssh_krl_check_key(struct ssh_krl *krl, const struct sshkey *key) 1315 { 1316 int r; 1317 1318 KRL_DBG(("checking key")); 1319 if ((r = is_key_revoked(krl, key)) != 0) 1320 return r; 1321 if (sshkey_is_cert(key)) { 1322 debug2_f("checking CA key"); 1323 if ((r = is_key_revoked(krl, key->cert->signature_key)) != 0) 1324 return r; 1325 } 1326 KRL_DBG(("key okay")); 1327 return 0; 1328 } 1329 1330 int 1331 ssh_krl_file_contains_key(const char *path, const struct sshkey *key) 1332 { 1333 struct sshbuf *krlbuf = NULL; 1334 struct ssh_krl *krl = NULL; 1335 int oerrno = 0, r; 1336 1337 if (path == NULL) 1338 return 0; 1339 if ((r = sshbuf_load_file(path, &krlbuf)) != 0) { 1340 oerrno = errno; 1341 goto out; 1342 } 1343 if ((r = ssh_krl_from_blob(krlbuf, &krl, NULL, 0)) != 0) 1344 goto out; 1345 debug2_f("checking KRL %s", path); 1346 r = ssh_krl_check_key(krl, key); 1347 out: 1348 sshbuf_free(krlbuf); 1349 ssh_krl_free(krl); 1350 if (r != 0) 1351 errno = oerrno; 1352 return r; 1353 } 1354 1355 int 1356 krl_dump(struct ssh_krl *krl, FILE *f) 1357 { 1358 struct sshkey *key = NULL; 1359 struct revoked_blob *rb; 1360 struct revoked_certs *rc; 1361 struct revoked_serial *rs; 1362 struct revoked_key_id *rki; 1363 int r, ret = 0; 1364 char *fp, timestamp[64]; 1365 1366 /* Try to print in a KRL spec-compatible format */ 1367 format_timestamp(krl->generated_date, timestamp, sizeof(timestamp)); 1368 fprintf(f, "# KRL version %llu\n", 1369 (unsigned long long)krl->krl_version); 1370 fprintf(f, "# Generated at %s\n", timestamp); 1371 if (krl->comment != NULL && *krl->comment != '\0') { 1372 r = INT_MAX; 1373 asmprintf(&fp, INT_MAX, &r, "%s", krl->comment); 1374 fprintf(f, "# Comment: %s\n", fp); 1375 free(fp); 1376 } 1377 fputc('\n', f); 1378 1379 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_keys) { 1380 if ((r = sshkey_from_blob(rb->blob, rb->len, &key)) != 0) { 1381 ret = SSH_ERR_INVALID_FORMAT; 1382 error_r(r, "parse KRL key"); 1383 continue; 1384 } 1385 if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT, 1386 SSH_FP_DEFAULT)) == NULL) { 1387 ret = SSH_ERR_INVALID_FORMAT; 1388 error("sshkey_fingerprint failed"); 1389 continue; 1390 } 1391 fprintf(f, "hash: %s # %s\n", fp, sshkey_ssh_name(key)); 1392 free(fp); 1393 free(key); 1394 } 1395 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha256s) { 1396 fp = tohex(rb->blob, rb->len); 1397 fprintf(f, "hash: SHA256:%s\n", fp); 1398 free(fp); 1399 } 1400 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha1s) { 1401 /* 1402 * There is not KRL spec keyword for raw SHA1 hashes, so 1403 * print them as comments. 1404 */ 1405 fp = tohex(rb->blob, rb->len); 1406 fprintf(f, "# hash SHA1:%s\n", fp); 1407 free(fp); 1408 } 1409 1410 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { 1411 fputc('\n', f); 1412 if (rc->ca_key == NULL) 1413 fprintf(f, "# Wildcard CA\n"); 1414 else { 1415 if ((fp = sshkey_fingerprint(rc->ca_key, 1416 SSH_FP_HASH_DEFAULT, SSH_FP_DEFAULT)) == NULL) { 1417 ret = SSH_ERR_INVALID_FORMAT; 1418 error("sshkey_fingerprint failed"); 1419 continue; 1420 } 1421 fprintf(f, "# CA key %s %s\n", 1422 sshkey_ssh_name(rc->ca_key), fp); 1423 free(fp); 1424 } 1425 RB_FOREACH(rs, revoked_serial_tree, &rc->revoked_serials) { 1426 if (rs->lo == rs->hi) { 1427 fprintf(f, "serial: %llu\n", 1428 (unsigned long long)rs->lo); 1429 } else { 1430 fprintf(f, "serial: %llu-%llu\n", 1431 (unsigned long long)rs->lo, 1432 (unsigned long long)rs->hi); 1433 } 1434 } 1435 RB_FOREACH(rki, revoked_key_id_tree, &rc->revoked_key_ids) { 1436 /* 1437 * We don't want key IDs with embedded newlines to 1438 * mess up the display. 1439 */ 1440 r = INT_MAX; 1441 asmprintf(&fp, INT_MAX, &r, "%s", rki->key_id); 1442 fprintf(f, "id: %s\n", fp); 1443 free(fp); 1444 } 1445 } 1446 return ret; 1447 } 1448