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 1.55 2023/03/14 07:28:47 dtucker 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 free(krl); 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(("new CA %s", ca_key == NULL ? "*" : sshkey_type(ca_key))); 246 *rcp = rc; 247 return 0; 248 } 249 250 static int 251 insert_serial_range(struct revoked_serial_tree *rt, u_int64_t lo, u_int64_t hi) 252 { 253 struct revoked_serial rs, *ers, *crs, *irs; 254 255 KRL_DBG(("insert %llu:%llu", lo, hi)); 256 memset(&rs, 0, sizeof(rs)); 257 rs.lo = lo; 258 rs.hi = hi; 259 ers = RB_NFIND(revoked_serial_tree, rt, &rs); 260 if (ers == NULL || serial_cmp(ers, &rs) != 0) { 261 /* No entry matches. Just insert */ 262 if ((irs = malloc(sizeof(rs))) == NULL) 263 return SSH_ERR_ALLOC_FAIL; 264 memcpy(irs, &rs, sizeof(*irs)); 265 ers = RB_INSERT(revoked_serial_tree, rt, irs); 266 if (ers != NULL) { 267 KRL_DBG(("bad: ers != NULL")); 268 /* Shouldn't happen */ 269 free(irs); 270 return SSH_ERR_INTERNAL_ERROR; 271 } 272 ers = irs; 273 } else { 274 KRL_DBG(("overlap found %llu:%llu", ers->lo, ers->hi)); 275 /* 276 * The inserted entry overlaps an existing one. Grow the 277 * existing entry. 278 */ 279 if (ers->lo > lo) 280 ers->lo = lo; 281 if (ers->hi < hi) 282 ers->hi = hi; 283 } 284 285 /* 286 * The inserted or revised range might overlap or abut adjacent ones; 287 * coalesce as necessary. 288 */ 289 290 /* Check predecessors */ 291 while ((crs = RB_PREV(revoked_serial_tree, rt, ers)) != NULL) { 292 KRL_DBG(("pred %llu:%llu", crs->lo, crs->hi)); 293 if (ers->lo != 0 && crs->hi < ers->lo - 1) 294 break; 295 /* This entry overlaps. */ 296 if (crs->lo < ers->lo) { 297 ers->lo = crs->lo; 298 KRL_DBG(("pred extend %llu:%llu", ers->lo, ers->hi)); 299 } 300 RB_REMOVE(revoked_serial_tree, rt, crs); 301 free(crs); 302 } 303 /* Check successors */ 304 while ((crs = RB_NEXT(revoked_serial_tree, rt, ers)) != NULL) { 305 KRL_DBG(("succ %llu:%llu", crs->lo, crs->hi)); 306 if (ers->hi != (u_int64_t)-1 && crs->lo > ers->hi + 1) 307 break; 308 /* This entry overlaps. */ 309 if (crs->hi > ers->hi) { 310 ers->hi = crs->hi; 311 KRL_DBG(("succ extend %llu:%llu", ers->lo, ers->hi)); 312 } 313 RB_REMOVE(revoked_serial_tree, rt, crs); 314 free(crs); 315 } 316 KRL_DBG(("done, final %llu:%llu", 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(("revoke %s", 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_f("revoke type %s", 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_f("revoke by sha1"); 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_f("revoke by sha256"); 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(("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", (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(("serial %llu:%llu state 0x%02x", 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(("finish state 0x%02x", 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(("start state 0x%02x", 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_f("insane bitmap gap"); 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(("serial final flush for state 0x%02x", state)); 695 switch (state) { 696 case KRL_SECTION_CERT_SERIAL_LIST: 697 case KRL_SECTION_CERT_SERIAL_RANGE: 698 break; 699 case KRL_SECTION_CERT_SERIAL_BITMAP: 700 if ((r = put_bitmap(sect, bitmap)) != 0) 701 goto out; 702 bitmap_free(bitmap); 703 bitmap = NULL; 704 break; 705 } 706 if ((r = sshbuf_put_u8(buf, state)) != 0 || 707 (r = sshbuf_put_stringb(buf, sect)) != 0) 708 goto out; 709 } 710 KRL_DBG(("serial done ")); 711 712 /* Now output a section for any revocations by key ID */ 713 sshbuf_reset(sect); 714 RB_FOREACH(rki, revoked_key_id_tree, &rc->revoked_key_ids) { 715 KRL_DBG(("key ID %s", rki->key_id)); 716 if ((r = sshbuf_put_cstring(sect, rki->key_id)) != 0) 717 goto out; 718 } 719 if (sshbuf_len(sect) != 0) { 720 if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERT_KEY_ID)) != 0 || 721 (r = sshbuf_put_stringb(buf, sect)) != 0) 722 goto out; 723 } 724 r = 0; 725 out: 726 bitmap_free(bitmap); 727 sshbuf_free(sect); 728 return r; 729 } 730 731 int 732 ssh_krl_to_blob(struct ssh_krl *krl, struct sshbuf *buf, 733 struct sshkey **sign_keys, u_int nsign_keys) 734 { 735 int r = SSH_ERR_INTERNAL_ERROR; 736 struct revoked_certs *rc; 737 struct revoked_blob *rb; 738 struct sshbuf *sect; 739 u_char *sblob = NULL; 740 size_t slen, i; 741 742 if (krl->generated_date == 0) 743 krl->generated_date = time(NULL); 744 745 if ((sect = sshbuf_new()) == NULL) 746 return SSH_ERR_ALLOC_FAIL; 747 748 /* Store the header */ 749 if ((r = sshbuf_put(buf, KRL_MAGIC, sizeof(KRL_MAGIC) - 1)) != 0 || 750 (r = sshbuf_put_u32(buf, KRL_FORMAT_VERSION)) != 0 || 751 (r = sshbuf_put_u64(buf, krl->krl_version)) != 0 || 752 (r = sshbuf_put_u64(buf, krl->generated_date)) != 0 || 753 (r = sshbuf_put_u64(buf, krl->flags)) != 0 || 754 (r = sshbuf_put_string(buf, NULL, 0)) != 0 || 755 (r = sshbuf_put_cstring(buf, krl->comment)) != 0) 756 goto out; 757 758 /* Store sections for revoked certificates */ 759 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { 760 sshbuf_reset(sect); 761 if ((r = revoked_certs_generate(rc, sect)) != 0) 762 goto out; 763 if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERTIFICATES)) != 0 || 764 (r = sshbuf_put_stringb(buf, sect)) != 0) 765 goto out; 766 } 767 768 /* Finally, output sections for revocations by public key/hash */ 769 sshbuf_reset(sect); 770 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_keys) { 771 KRL_DBG(("key len %zu ", rb->len)); 772 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 773 goto out; 774 } 775 if (sshbuf_len(sect) != 0) { 776 if ((r = sshbuf_put_u8(buf, KRL_SECTION_EXPLICIT_KEY)) != 0 || 777 (r = sshbuf_put_stringb(buf, sect)) != 0) 778 goto out; 779 } 780 sshbuf_reset(sect); 781 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha1s) { 782 KRL_DBG(("hash len %zu ", rb->len)); 783 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 784 goto out; 785 } 786 if (sshbuf_len(sect) != 0) { 787 if ((r = sshbuf_put_u8(buf, 788 KRL_SECTION_FINGERPRINT_SHA1)) != 0 || 789 (r = sshbuf_put_stringb(buf, sect)) != 0) 790 goto out; 791 } 792 sshbuf_reset(sect); 793 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha256s) { 794 KRL_DBG(("hash len %zu ", rb->len)); 795 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0) 796 goto out; 797 } 798 if (sshbuf_len(sect) != 0) { 799 if ((r = sshbuf_put_u8(buf, 800 KRL_SECTION_FINGERPRINT_SHA256)) != 0 || 801 (r = sshbuf_put_stringb(buf, sect)) != 0) 802 goto out; 803 } 804 805 for (i = 0; i < nsign_keys; i++) { 806 KRL_DBG(("sig key %s", sshkey_ssh_name(sign_keys[i]))); 807 if ((r = sshbuf_put_u8(buf, KRL_SECTION_SIGNATURE)) != 0 || 808 (r = sshkey_puts(sign_keys[i], buf)) != 0) 809 goto out; 810 /* XXX support sk-* keys */ 811 if ((r = sshkey_sign(sign_keys[i], &sblob, &slen, 812 sshbuf_ptr(buf), sshbuf_len(buf), NULL, NULL, 813 NULL, 0)) != 0) 814 goto out; 815 KRL_DBG(("signature sig len %zu", slen)); 816 if ((r = sshbuf_put_string(buf, sblob, slen)) != 0) 817 goto out; 818 } 819 820 r = 0; 821 out: 822 free(sblob); 823 sshbuf_free(sect); 824 return r; 825 } 826 827 static void 828 format_timestamp(u_int64_t timestamp, char *ts, size_t nts) 829 { 830 time_t t; 831 struct tm *tm; 832 833 t = timestamp; 834 tm = localtime(&t); 835 if (tm == NULL) 836 strlcpy(ts, "<INVALID>", nts); 837 else { 838 *ts = '\0'; 839 strftime(ts, nts, "%Y%m%dT%H%M%S", tm); 840 } 841 } 842 843 static int 844 parse_revoked_certs(struct sshbuf *buf, struct ssh_krl *krl) 845 { 846 int r = SSH_ERR_INTERNAL_ERROR; 847 u_char type; 848 const u_char *blob; 849 size_t blen, nbits; 850 struct sshbuf *subsect = NULL; 851 u_int64_t serial, serial_lo, serial_hi; 852 struct bitmap *bitmap = NULL; 853 char *key_id = NULL; 854 struct sshkey *ca_key = NULL; 855 856 if ((subsect = sshbuf_new()) == NULL) 857 return SSH_ERR_ALLOC_FAIL; 858 859 /* Header: key, reserved */ 860 if ((r = sshbuf_get_string_direct(buf, &blob, &blen)) != 0 || 861 (r = sshbuf_skip_string(buf)) != 0) 862 goto out; 863 if (blen != 0 && (r = sshkey_from_blob(blob, blen, &ca_key)) != 0) 864 goto out; 865 866 while (sshbuf_len(buf) > 0) { 867 sshbuf_free(subsect); 868 subsect = NULL; 869 if ((r = sshbuf_get_u8(buf, &type)) != 0 || 870 (r = sshbuf_froms(buf, &subsect)) != 0) 871 goto out; 872 KRL_DBG(("subsection type 0x%02x", type)); 873 /* sshbuf_dump(subsect, stderr); */ 874 875 switch (type) { 876 case KRL_SECTION_CERT_SERIAL_LIST: 877 while (sshbuf_len(subsect) > 0) { 878 if ((r = sshbuf_get_u64(subsect, &serial)) != 0) 879 goto out; 880 if ((r = ssh_krl_revoke_cert_by_serial(krl, 881 ca_key, serial)) != 0) 882 goto out; 883 } 884 break; 885 case KRL_SECTION_CERT_SERIAL_RANGE: 886 if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 || 887 (r = sshbuf_get_u64(subsect, &serial_hi)) != 0) 888 goto out; 889 if ((r = ssh_krl_revoke_cert_by_serial_range(krl, 890 ca_key, serial_lo, serial_hi)) != 0) 891 goto out; 892 break; 893 case KRL_SECTION_CERT_SERIAL_BITMAP: 894 if ((bitmap = bitmap_new()) == NULL) { 895 r = SSH_ERR_ALLOC_FAIL; 896 goto out; 897 } 898 if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 || 899 (r = sshbuf_get_bignum2_bytes_direct(subsect, 900 &blob, &blen)) != 0) 901 goto out; 902 if (bitmap_from_string(bitmap, blob, blen) != 0) { 903 r = SSH_ERR_INVALID_FORMAT; 904 goto out; 905 } 906 nbits = bitmap_nbits(bitmap); 907 for (serial = 0; serial < (u_int64_t)nbits; serial++) { 908 if (serial > 0 && serial_lo + serial == 0) { 909 error_f("bitmap wraps u64"); 910 r = SSH_ERR_INVALID_FORMAT; 911 goto out; 912 } 913 if (!bitmap_test_bit(bitmap, serial)) 914 continue; 915 if ((r = ssh_krl_revoke_cert_by_serial(krl, 916 ca_key, serial_lo + serial)) != 0) 917 goto out; 918 } 919 bitmap_free(bitmap); 920 bitmap = NULL; 921 break; 922 case KRL_SECTION_CERT_KEY_ID: 923 while (sshbuf_len(subsect) > 0) { 924 if ((r = sshbuf_get_cstring(subsect, 925 &key_id, NULL)) != 0) 926 goto out; 927 if ((r = ssh_krl_revoke_cert_by_key_id(krl, 928 ca_key, key_id)) != 0) 929 goto out; 930 free(key_id); 931 key_id = NULL; 932 } 933 break; 934 default: 935 error("Unsupported KRL certificate section %u", type); 936 r = SSH_ERR_INVALID_FORMAT; 937 goto out; 938 } 939 if (sshbuf_len(subsect) > 0) { 940 error("KRL certificate section contains unparsed data"); 941 r = SSH_ERR_INVALID_FORMAT; 942 goto out; 943 } 944 } 945 946 r = 0; 947 out: 948 if (bitmap != NULL) 949 bitmap_free(bitmap); 950 free(key_id); 951 sshkey_free(ca_key); 952 sshbuf_free(subsect); 953 return r; 954 } 955 956 static int 957 blob_section(struct sshbuf *sect, struct revoked_blob_tree *target_tree, 958 size_t expected_len) 959 { 960 u_char *rdata = NULL; 961 size_t rlen = 0; 962 int r; 963 964 while (sshbuf_len(sect) > 0) { 965 if ((r = sshbuf_get_string(sect, &rdata, &rlen)) != 0) 966 return r; 967 if (expected_len != 0 && rlen != expected_len) { 968 error_f("bad length"); 969 free(rdata); 970 return SSH_ERR_INVALID_FORMAT; 971 } 972 if ((r = revoke_blob(target_tree, rdata, rlen)) != 0) { 973 free(rdata); 974 return r; 975 } 976 } 977 return 0; 978 } 979 980 /* Attempt to parse a KRL, checking its signature (if any) with sign_ca_keys. */ 981 int 982 ssh_krl_from_blob(struct sshbuf *buf, struct ssh_krl **krlp, 983 const struct sshkey **sign_ca_keys, size_t nsign_ca_keys) 984 { 985 struct sshbuf *copy = NULL, *sect = NULL; 986 struct ssh_krl *krl = NULL; 987 char timestamp[64]; 988 int r = SSH_ERR_INTERNAL_ERROR, sig_seen; 989 struct sshkey *key = NULL, **ca_used = NULL, **tmp_ca_used; 990 u_char type; 991 const u_char *blob; 992 size_t i, j, sig_off, sects_off, blen, nca_used; 993 u_int format_version; 994 995 nca_used = 0; 996 *krlp = NULL; 997 if (sshbuf_len(buf) < sizeof(KRL_MAGIC) - 1 || 998 memcmp(sshbuf_ptr(buf), KRL_MAGIC, sizeof(KRL_MAGIC) - 1) != 0) { 999 debug3_f("not a KRL"); 1000 return SSH_ERR_KRL_BAD_MAGIC; 1001 } 1002 1003 /* Take a copy of the KRL buffer so we can verify its signature later */ 1004 if ((copy = sshbuf_fromb(buf)) == NULL) { 1005 r = SSH_ERR_ALLOC_FAIL; 1006 goto out; 1007 } 1008 if ((r = sshbuf_consume(copy, sizeof(KRL_MAGIC) - 1)) != 0) 1009 goto out; 1010 1011 if ((krl = ssh_krl_init()) == NULL) { 1012 error_f("alloc failed"); 1013 goto out; 1014 } 1015 1016 if ((r = sshbuf_get_u32(copy, &format_version)) != 0) 1017 goto out; 1018 if (format_version != KRL_FORMAT_VERSION) { 1019 r = SSH_ERR_INVALID_FORMAT; 1020 goto out; 1021 } 1022 if ((r = sshbuf_get_u64(copy, &krl->krl_version)) != 0 || 1023 (r = sshbuf_get_u64(copy, &krl->generated_date)) != 0 || 1024 (r = sshbuf_get_u64(copy, &krl->flags)) != 0 || 1025 (r = sshbuf_skip_string(copy)) != 0 || 1026 (r = sshbuf_get_cstring(copy, &krl->comment, NULL)) != 0) 1027 goto out; 1028 1029 format_timestamp(krl->generated_date, timestamp, sizeof(timestamp)); 1030 debug("KRL version %llu generated at %s%s%s", 1031 (long long unsigned)krl->krl_version, timestamp, 1032 *krl->comment ? ": " : "", krl->comment); 1033 1034 /* 1035 * 1st pass: verify signatures, if any. This is done to avoid 1036 * detailed parsing of data whose provenance is unverified. 1037 */ 1038 sig_seen = 0; 1039 if (sshbuf_len(buf) < sshbuf_len(copy)) { 1040 /* Shouldn't happen */ 1041 r = SSH_ERR_INTERNAL_ERROR; 1042 goto out; 1043 } 1044 sects_off = sshbuf_len(buf) - sshbuf_len(copy); 1045 while (sshbuf_len(copy) > 0) { 1046 if ((r = sshbuf_get_u8(copy, &type)) != 0 || 1047 (r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0) 1048 goto out; 1049 KRL_DBG(("first pass, section 0x%02x", type)); 1050 if (type != KRL_SECTION_SIGNATURE) { 1051 if (sig_seen) { 1052 error("KRL contains non-signature section " 1053 "after signature"); 1054 r = SSH_ERR_INVALID_FORMAT; 1055 goto out; 1056 } 1057 /* Not interested for now. */ 1058 continue; 1059 } 1060 sig_seen = 1; 1061 /* First string component is the signing key */ 1062 if ((r = sshkey_from_blob(blob, blen, &key)) != 0) { 1063 r = SSH_ERR_INVALID_FORMAT; 1064 goto out; 1065 } 1066 if (sshbuf_len(buf) < sshbuf_len(copy)) { 1067 /* Shouldn't happen */ 1068 r = SSH_ERR_INTERNAL_ERROR; 1069 goto out; 1070 } 1071 sig_off = sshbuf_len(buf) - sshbuf_len(copy); 1072 /* Second string component is the signature itself */ 1073 if ((r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0) { 1074 r = SSH_ERR_INVALID_FORMAT; 1075 goto out; 1076 } 1077 /* Check signature over entire KRL up to this point */ 1078 if ((r = sshkey_verify(key, blob, blen, 1079 sshbuf_ptr(buf), sig_off, NULL, 0, NULL)) != 0) 1080 goto out; 1081 /* Check if this key has already signed this KRL */ 1082 for (i = 0; i < nca_used; i++) { 1083 if (sshkey_equal(ca_used[i], key)) { 1084 error("KRL signed more than once with " 1085 "the same key"); 1086 r = SSH_ERR_INVALID_FORMAT; 1087 goto out; 1088 } 1089 } 1090 /* Record keys used to sign the KRL */ 1091 tmp_ca_used = recallocarray(ca_used, nca_used, nca_used + 1, 1092 sizeof(*ca_used)); 1093 if (tmp_ca_used == NULL) { 1094 r = SSH_ERR_ALLOC_FAIL; 1095 goto out; 1096 } 1097 ca_used = tmp_ca_used; 1098 ca_used[nca_used++] = key; 1099 key = NULL; 1100 } 1101 1102 if (sshbuf_len(copy) != 0) { 1103 /* Shouldn't happen */ 1104 r = SSH_ERR_INTERNAL_ERROR; 1105 goto out; 1106 } 1107 1108 /* 1109 * 2nd pass: parse and load the KRL, skipping the header to the point 1110 * where the section start. 1111 */ 1112 sshbuf_free(copy); 1113 if ((copy = sshbuf_fromb(buf)) == NULL) { 1114 r = SSH_ERR_ALLOC_FAIL; 1115 goto out; 1116 } 1117 if ((r = sshbuf_consume(copy, sects_off)) != 0) 1118 goto out; 1119 while (sshbuf_len(copy) > 0) { 1120 sshbuf_free(sect); 1121 sect = NULL; 1122 if ((r = sshbuf_get_u8(copy, &type)) != 0 || 1123 (r = sshbuf_froms(copy, §)) != 0) 1124 goto out; 1125 KRL_DBG(("second pass, section 0x%02x", type)); 1126 1127 switch (type) { 1128 case KRL_SECTION_CERTIFICATES: 1129 if ((r = parse_revoked_certs(sect, krl)) != 0) 1130 goto out; 1131 break; 1132 case KRL_SECTION_EXPLICIT_KEY: 1133 if ((r = blob_section(sect, 1134 &krl->revoked_keys, 0)) != 0) 1135 goto out; 1136 break; 1137 case KRL_SECTION_FINGERPRINT_SHA1: 1138 if ((r = blob_section(sect, 1139 &krl->revoked_sha1s, 20)) != 0) 1140 goto out; 1141 break; 1142 case KRL_SECTION_FINGERPRINT_SHA256: 1143 if ((r = blob_section(sect, 1144 &krl->revoked_sha256s, 32)) != 0) 1145 goto out; 1146 break; 1147 case KRL_SECTION_SIGNATURE: 1148 /* Handled above, but still need to stay in synch */ 1149 sshbuf_free(sect); 1150 sect = NULL; 1151 if ((r = sshbuf_skip_string(copy)) != 0) 1152 goto out; 1153 break; 1154 default: 1155 error("Unsupported KRL section %u", type); 1156 r = SSH_ERR_INVALID_FORMAT; 1157 goto out; 1158 } 1159 if (sect != NULL && sshbuf_len(sect) > 0) { 1160 error("KRL section contains unparsed data"); 1161 r = SSH_ERR_INVALID_FORMAT; 1162 goto out; 1163 } 1164 } 1165 1166 /* Check that the key(s) used to sign the KRL weren't revoked */ 1167 sig_seen = 0; 1168 for (i = 0; i < nca_used; i++) { 1169 if (ssh_krl_check_key(krl, ca_used[i]) == 0) 1170 sig_seen = 1; 1171 else { 1172 sshkey_free(ca_used[i]); 1173 ca_used[i] = NULL; 1174 } 1175 } 1176 if (nca_used && !sig_seen) { 1177 error("All keys used to sign KRL were revoked"); 1178 r = SSH_ERR_KEY_REVOKED; 1179 goto out; 1180 } 1181 1182 /* If we have CA keys, then verify that one was used to sign the KRL */ 1183 if (sig_seen && nsign_ca_keys != 0) { 1184 sig_seen = 0; 1185 for (i = 0; !sig_seen && i < nsign_ca_keys; i++) { 1186 for (j = 0; j < nca_used; j++) { 1187 if (ca_used[j] == NULL) 1188 continue; 1189 if (sshkey_equal(ca_used[j], sign_ca_keys[i])) { 1190 sig_seen = 1; 1191 break; 1192 } 1193 } 1194 } 1195 if (!sig_seen) { 1196 r = SSH_ERR_SIGNATURE_INVALID; 1197 error("KRL not signed with any trusted key"); 1198 goto out; 1199 } 1200 } 1201 1202 *krlp = krl; 1203 r = 0; 1204 out: 1205 if (r != 0) 1206 ssh_krl_free(krl); 1207 for (i = 0; i < nca_used; i++) 1208 sshkey_free(ca_used[i]); 1209 free(ca_used); 1210 sshkey_free(key); 1211 sshbuf_free(copy); 1212 sshbuf_free(sect); 1213 return r; 1214 } 1215 1216 /* Checks certificate serial number and key ID revocation */ 1217 static int 1218 is_cert_revoked(const struct sshkey *key, struct revoked_certs *rc) 1219 { 1220 struct revoked_serial rs, *ers; 1221 struct revoked_key_id rki, *erki; 1222 1223 /* Check revocation by cert key ID */ 1224 memset(&rki, 0, sizeof(rki)); 1225 rki.key_id = key->cert->key_id; 1226 erki = RB_FIND(revoked_key_id_tree, &rc->revoked_key_ids, &rki); 1227 if (erki != NULL) { 1228 KRL_DBG(("revoked by key ID")); 1229 return SSH_ERR_KEY_REVOKED; 1230 } 1231 1232 /* 1233 * Zero serials numbers are ignored (it's the default when the 1234 * CA doesn't specify one). 1235 */ 1236 if (key->cert->serial == 0) 1237 return 0; 1238 1239 memset(&rs, 0, sizeof(rs)); 1240 rs.lo = rs.hi = key->cert->serial; 1241 ers = RB_FIND(revoked_serial_tree, &rc->revoked_serials, &rs); 1242 if (ers != NULL) { 1243 KRL_DBG(("revoked serial %llu matched %llu:%llu", 1244 key->cert->serial, ers->lo, ers->hi)); 1245 return SSH_ERR_KEY_REVOKED; 1246 } 1247 return 0; 1248 } 1249 1250 /* Checks whether a given key/cert is revoked. Does not check its CA */ 1251 static int 1252 is_key_revoked(struct ssh_krl *krl, const struct sshkey *key) 1253 { 1254 struct revoked_blob rb, *erb; 1255 struct revoked_certs *rc; 1256 int r; 1257 1258 /* Check explicitly revoked hashes first */ 1259 memset(&rb, 0, sizeof(rb)); 1260 if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA1, 1261 &rb.blob, &rb.len)) != 0) 1262 return r; 1263 erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha1s, &rb); 1264 free(rb.blob); 1265 if (erb != NULL) { 1266 KRL_DBG(("revoked by key SHA1")); 1267 return SSH_ERR_KEY_REVOKED; 1268 } 1269 memset(&rb, 0, sizeof(rb)); 1270 if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA256, 1271 &rb.blob, &rb.len)) != 0) 1272 return r; 1273 erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha256s, &rb); 1274 free(rb.blob); 1275 if (erb != NULL) { 1276 KRL_DBG(("revoked by key SHA256")); 1277 return SSH_ERR_KEY_REVOKED; 1278 } 1279 1280 /* Next, explicit keys */ 1281 memset(&rb, 0, sizeof(rb)); 1282 if ((r = plain_key_blob(key, &rb.blob, &rb.len)) != 0) 1283 return r; 1284 erb = RB_FIND(revoked_blob_tree, &krl->revoked_keys, &rb); 1285 free(rb.blob); 1286 if (erb != NULL) { 1287 KRL_DBG(("revoked by explicit key")); 1288 return SSH_ERR_KEY_REVOKED; 1289 } 1290 1291 if (!sshkey_is_cert(key)) 1292 return 0; 1293 1294 /* Check cert revocation for the specified CA */ 1295 if ((r = revoked_certs_for_ca_key(krl, key->cert->signature_key, 1296 &rc, 0)) != 0) 1297 return r; 1298 if (rc != NULL) { 1299 if ((r = is_cert_revoked(key, rc)) != 0) 1300 return r; 1301 } 1302 /* Check cert revocation for the wildcard CA */ 1303 if ((r = revoked_certs_for_ca_key(krl, NULL, &rc, 0)) != 0) 1304 return r; 1305 if (rc != NULL) { 1306 if ((r = is_cert_revoked(key, rc)) != 0) 1307 return r; 1308 } 1309 1310 KRL_DBG(("%llu no match", key->cert->serial)); 1311 return 0; 1312 } 1313 1314 int 1315 ssh_krl_check_key(struct ssh_krl *krl, const struct sshkey *key) 1316 { 1317 int r; 1318 1319 KRL_DBG(("checking key")); 1320 if ((r = is_key_revoked(krl, key)) != 0) 1321 return r; 1322 if (sshkey_is_cert(key)) { 1323 debug2_f("checking CA key"); 1324 if ((r = is_key_revoked(krl, key->cert->signature_key)) != 0) 1325 return r; 1326 } 1327 KRL_DBG(("key okay")); 1328 return 0; 1329 } 1330 1331 int 1332 ssh_krl_file_contains_key(const char *path, const struct sshkey *key) 1333 { 1334 struct sshbuf *krlbuf = NULL; 1335 struct ssh_krl *krl = NULL; 1336 int oerrno = 0, r; 1337 1338 if (path == NULL) 1339 return 0; 1340 if ((r = sshbuf_load_file(path, &krlbuf)) != 0) { 1341 oerrno = errno; 1342 goto out; 1343 } 1344 if ((r = ssh_krl_from_blob(krlbuf, &krl, NULL, 0)) != 0) 1345 goto out; 1346 debug2_f("checking KRL %s", path); 1347 r = ssh_krl_check_key(krl, key); 1348 out: 1349 sshbuf_free(krlbuf); 1350 ssh_krl_free(krl); 1351 if (r != 0) 1352 errno = oerrno; 1353 return r; 1354 } 1355 1356 int 1357 krl_dump(struct ssh_krl *krl, FILE *f) 1358 { 1359 struct sshkey *key = NULL; 1360 struct revoked_blob *rb; 1361 struct revoked_certs *rc; 1362 struct revoked_serial *rs; 1363 struct revoked_key_id *rki; 1364 int r, ret = 0; 1365 char *fp, timestamp[64]; 1366 1367 /* Try to print in a KRL spec-compatible format */ 1368 format_timestamp(krl->generated_date, timestamp, sizeof(timestamp)); 1369 fprintf(f, "# KRL version %llu\n", 1370 (unsigned long long)krl->krl_version); 1371 fprintf(f, "# Generated at %s\n", timestamp); 1372 if (krl->comment != NULL && *krl->comment != '\0') { 1373 r = INT_MAX; 1374 asmprintf(&fp, INT_MAX, &r, "%s", krl->comment); 1375 fprintf(f, "# Comment: %s\n", fp); 1376 free(fp); 1377 } 1378 fputc('\n', f); 1379 1380 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_keys) { 1381 if ((r = sshkey_from_blob(rb->blob, rb->len, &key)) != 0) { 1382 ret = SSH_ERR_INVALID_FORMAT; 1383 error_r(r, "parse KRL key"); 1384 continue; 1385 } 1386 if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT, 1387 SSH_FP_DEFAULT)) == NULL) { 1388 ret = SSH_ERR_INVALID_FORMAT; 1389 error("sshkey_fingerprint failed"); 1390 continue; 1391 } 1392 fprintf(f, "hash: %s # %s\n", fp, sshkey_ssh_name(key)); 1393 free(fp); 1394 free(key); 1395 } 1396 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha256s) { 1397 fp = tohex(rb->blob, rb->len); 1398 fprintf(f, "hash: SHA256:%s\n", fp); 1399 free(fp); 1400 } 1401 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha1s) { 1402 /* 1403 * There is not KRL spec keyword for raw SHA1 hashes, so 1404 * print them as comments. 1405 */ 1406 fp = tohex(rb->blob, rb->len); 1407 fprintf(f, "# hash SHA1:%s\n", fp); 1408 free(fp); 1409 } 1410 1411 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { 1412 fputc('\n', f); 1413 if (rc->ca_key == NULL) 1414 fprintf(f, "# Wildcard CA\n"); 1415 else { 1416 if ((fp = sshkey_fingerprint(rc->ca_key, 1417 SSH_FP_HASH_DEFAULT, SSH_FP_DEFAULT)) == NULL) { 1418 ret = SSH_ERR_INVALID_FORMAT; 1419 error("sshkey_fingerprint failed"); 1420 continue; 1421 } 1422 fprintf(f, "# CA key %s %s\n", 1423 sshkey_ssh_name(rc->ca_key), fp); 1424 free(fp); 1425 } 1426 RB_FOREACH(rs, revoked_serial_tree, &rc->revoked_serials) { 1427 if (rs->lo == rs->hi) { 1428 fprintf(f, "serial: %llu\n", 1429 (unsigned long long)rs->lo); 1430 } else { 1431 fprintf(f, "serial: %llu-%llu\n", 1432 (unsigned long long)rs->lo, 1433 (unsigned long long)rs->hi); 1434 } 1435 } 1436 RB_FOREACH(rki, revoked_key_id_tree, &rc->revoked_key_ids) { 1437 /* 1438 * We don't want key IDs with embedded newlines to 1439 * mess up the display. 1440 */ 1441 r = INT_MAX; 1442 asmprintf(&fp, INT_MAX, &r, "%s", rki->key_id); 1443 fprintf(f, "id: %s\n", fp); 1444 free(fp); 1445 } 1446 } 1447 return ret; 1448 } 1449