2 * Copyright (c) 2012 Damien Miller <djm@mindrot.org>
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.
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.
17 /* $OpenBSD: krl.c,v 1.9 2013/01/27 10:06:12 djm Exp $ */
21 #include <sys/types.h>
22 #include <sys/param.h>
23 #include <openbsd-compat/sys-tree.h>
24 #include <openbsd-compat/sys-queue.h>
42 /* #define DEBUG_KRL */
44 # define KRL_DBG(x) debug3 x
50 * Trees of revoked serial numbers, key IDs and keys. This allows
51 * quick searching, querying and producing lists in canonical order.
54 /* Tree of serial numbers. XXX make smarter: really need a real sparse bitmap */
55 struct revoked_serial {
57 RB_ENTRY(revoked_serial) tree_entry;
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);
64 struct revoked_key_id {
66 RB_ENTRY(revoked_key_id) tree_entry;
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);
72 /* Tree of blobs (used for keys and fingerprints) */
76 RB_ENTRY(revoked_blob) tree_entry;
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);
82 /* Tracks revoked certs for a single CA */
83 struct revoked_certs {
85 struct revoked_serial_tree revoked_serials;
86 struct revoked_key_id_tree revoked_key_ids;
87 TAILQ_ENTRY(revoked_certs) entry;
89 TAILQ_HEAD(revoked_certs_list, revoked_certs);
92 u_int64_t krl_version;
93 u_int64_t generated_date;
96 struct revoked_blob_tree revoked_keys;
97 struct revoked_blob_tree revoked_sha1s;
98 struct revoked_certs_list revoked_certs;
101 /* Return equal if a and b overlap */
103 serial_cmp(struct revoked_serial *a, struct revoked_serial *b)
105 if (a->hi >= b->lo && a->lo <= b->hi)
107 return a->lo < b->lo ? -1 : 1;
111 key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b)
113 return strcmp(a->key_id, b->key_id);
117 blob_cmp(struct revoked_blob *a, struct revoked_blob *b)
121 if (a->len != b->len) {
122 if ((r = memcmp(a->blob, b->blob, MIN(a->len, b->len))) != 0)
124 return a->len > b->len ? 1 : -1;
126 return memcmp(a->blob, b->blob, a->len);
134 if ((krl = calloc(1, sizeof(*krl))) == NULL)
136 RB_INIT(&krl->revoked_keys);
137 RB_INIT(&krl->revoked_sha1s);
138 TAILQ_INIT(&krl->revoked_certs);
143 revoked_certs_free(struct revoked_certs *rc)
145 struct revoked_serial *rs, *trs;
146 struct revoked_key_id *rki, *trki;
148 RB_FOREACH_SAFE(rs, revoked_serial_tree, &rc->revoked_serials, trs) {
149 RB_REMOVE(revoked_serial_tree, &rc->revoked_serials, rs);
152 RB_FOREACH_SAFE(rki, revoked_key_id_tree, &rc->revoked_key_ids, trki) {
153 RB_REMOVE(revoked_key_id_tree, &rc->revoked_key_ids, rki);
157 if (rc->ca_key != NULL)
158 key_free(rc->ca_key);
162 ssh_krl_free(struct ssh_krl *krl)
164 struct revoked_blob *rb, *trb;
165 struct revoked_certs *rc, *trc;
171 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_keys, trb) {
172 RB_REMOVE(revoked_blob_tree, &krl->revoked_keys, rb);
176 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha1s, trb) {
177 RB_REMOVE(revoked_blob_tree, &krl->revoked_sha1s, rb);
181 TAILQ_FOREACH_SAFE(rc, &krl->revoked_certs, entry, trc) {
182 TAILQ_REMOVE(&krl->revoked_certs, rc, entry);
183 revoked_certs_free(rc);
188 ssh_krl_set_version(struct ssh_krl *krl, u_int64_t version)
190 krl->krl_version = version;
194 ssh_krl_set_comment(struct ssh_krl *krl, const char *comment)
197 if ((krl->comment = strdup(comment)) == NULL)
198 fatal("%s: strdup", __func__);
202 * Find the revoked_certs struct for a CA key. If allow_create is set then
203 * create a new one in the tree if one did not exist already.
206 revoked_certs_for_ca_key(struct ssh_krl *krl, const Key *ca_key,
207 struct revoked_certs **rcp, int allow_create)
209 struct revoked_certs *rc;
212 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) {
213 if (key_equal(rc->ca_key, ca_key)) {
220 /* If this CA doesn't exist in the list then add it now */
221 if ((rc = calloc(1, sizeof(*rc))) == NULL)
223 if ((rc->ca_key = key_from_private(ca_key)) == NULL) {
227 RB_INIT(&rc->revoked_serials);
228 RB_INIT(&rc->revoked_key_ids);
229 TAILQ_INSERT_TAIL(&krl->revoked_certs, rc, entry);
230 debug3("%s: new CA %s", __func__, key_type(ca_key));
236 insert_serial_range(struct revoked_serial_tree *rt, u_int64_t lo, u_int64_t hi)
238 struct revoked_serial rs, *ers, *crs, *irs;
240 KRL_DBG(("%s: insert %llu:%llu", __func__, lo, hi));
241 bzero(&rs, sizeof(rs));
244 ers = RB_NFIND(revoked_serial_tree, rt, &rs);
245 if (ers == NULL || serial_cmp(ers, &rs) != 0) {
246 /* No entry matches. Just insert */
247 if ((irs = malloc(sizeof(rs))) == NULL)
249 memcpy(irs, &rs, sizeof(*irs));
250 ers = RB_INSERT(revoked_serial_tree, rt, irs);
252 KRL_DBG(("%s: bad: ers != NULL", __func__));
253 /* Shouldn't happen */
259 KRL_DBG(("%s: overlap found %llu:%llu", __func__,
262 * The inserted entry overlaps an existing one. Grow the
271 * The inserted or revised range might overlap or abut adjacent ones;
272 * coalesce as necessary.
275 /* Check predecessors */
276 while ((crs = RB_PREV(revoked_serial_tree, rt, ers)) != NULL) {
277 KRL_DBG(("%s: pred %llu:%llu", __func__, crs->lo, crs->hi));
278 if (ers->lo != 0 && crs->hi < ers->lo - 1)
280 /* This entry overlaps. */
281 if (crs->lo < ers->lo) {
283 KRL_DBG(("%s: pred extend %llu:%llu", __func__,
286 RB_REMOVE(revoked_serial_tree, rt, crs);
289 /* Check successors */
290 while ((crs = RB_NEXT(revoked_serial_tree, rt, ers)) != NULL) {
291 KRL_DBG(("%s: succ %llu:%llu", __func__, crs->lo, crs->hi));
292 if (ers->hi != (u_int64_t)-1 && crs->lo > ers->hi + 1)
294 /* This entry overlaps. */
295 if (crs->hi > ers->hi) {
297 KRL_DBG(("%s: succ extend %llu:%llu", __func__,
300 RB_REMOVE(revoked_serial_tree, rt, crs);
303 KRL_DBG(("%s: done, final %llu:%llu", __func__, ers->lo, ers->hi));
308 ssh_krl_revoke_cert_by_serial(struct ssh_krl *krl, const Key *ca_key,
311 return ssh_krl_revoke_cert_by_serial_range(krl, ca_key, serial, serial);
315 ssh_krl_revoke_cert_by_serial_range(struct ssh_krl *krl, const Key *ca_key,
316 u_int64_t lo, u_int64_t hi)
318 struct revoked_certs *rc;
320 if (lo > hi || lo == 0)
322 if (revoked_certs_for_ca_key(krl, ca_key, &rc, 1) != 0)
324 return insert_serial_range(&rc->revoked_serials, lo, hi);
328 ssh_krl_revoke_cert_by_key_id(struct ssh_krl *krl, const Key *ca_key,
331 struct revoked_key_id *rki, *erki;
332 struct revoked_certs *rc;
334 if (revoked_certs_for_ca_key(krl, ca_key, &rc, 1) != 0)
337 debug3("%s: revoke %s", __func__, key_id);
338 if ((rki = calloc(1, sizeof(*rki))) == NULL ||
339 (rki->key_id = strdup(key_id)) == NULL) {
341 fatal("%s: strdup", __func__);
343 erki = RB_INSERT(revoked_key_id_tree, &rc->revoked_key_ids, rki);
351 /* Convert "key" to a public key blob without any certificate information */
353 plain_key_blob(const Key *key, u_char **blob, u_int *blen)
358 if ((kcopy = key_from_private(key)) == NULL)
360 if (key_is_cert(kcopy)) {
361 if (key_drop_cert(kcopy) != 0) {
362 error("%s: key_drop_cert", __func__);
367 r = key_to_blob(kcopy, blob, blen);
369 return r == 0 ? -1 : 0;
372 /* Revoke a key blob. Ownership of blob is transferred to the tree */
374 revoke_blob(struct revoked_blob_tree *rbt, u_char *blob, u_int len)
376 struct revoked_blob *rb, *erb;
378 if ((rb = calloc(1, sizeof(*rb))) == NULL)
382 erb = RB_INSERT(revoked_blob_tree, rbt, rb);
391 ssh_krl_revoke_key_explicit(struct ssh_krl *krl, const Key *key)
396 debug3("%s: revoke type %s", __func__, key_type(key));
397 if (plain_key_blob(key, &blob, &len) != 0)
399 return revoke_blob(&krl->revoked_keys, blob, len);
403 ssh_krl_revoke_key_sha1(struct ssh_krl *krl, const Key *key)
408 debug3("%s: revoke type %s by sha1", __func__, key_type(key));
409 if ((blob = key_fingerprint_raw(key, SSH_FP_SHA1, &len)) == NULL)
411 return revoke_blob(&krl->revoked_sha1s, blob, len);
415 ssh_krl_revoke_key(struct ssh_krl *krl, const Key *key)
417 if (!key_is_cert(key))
418 return ssh_krl_revoke_key_sha1(krl, key);
420 if (key_cert_is_legacy(key) || key->cert->serial == 0) {
421 return ssh_krl_revoke_cert_by_key_id(krl,
422 key->cert->signature_key,
425 return ssh_krl_revoke_cert_by_serial(krl,
426 key->cert->signature_key,
432 * Select a copact next section type to emit in a KRL based on the
433 * current section type, the run length of contiguous revoked serial
434 * numbers and the gaps from the last and to the next revoked serial.
435 * Applies a mostly-accurate bit cost model to select the section type
436 * that will minimise the size of the resultant KRL.
439 choose_next_state(int current_state, u_int64_t contig, int final,
440 u_int64_t last_gap, u_int64_t next_gap, int *force_new_section)
443 u_int64_t cost, cost_list, cost_range, cost_bitmap, cost_bitmap_restart;
446 * Avoid unsigned overflows.
447 * The limits are high enough to avoid confusing the calculations.
449 contig = MIN(contig, 1ULL<<31);
450 last_gap = MIN(last_gap, 1ULL<<31);
451 next_gap = MIN(next_gap, 1ULL<<31);
454 * Calculate the cost to switch from the current state to candidates.
455 * NB. range sections only ever contain a single range, so their
456 * switching cost is independent of the current_state.
458 cost_list = cost_bitmap = cost_bitmap_restart = 0;
460 switch (current_state) {
461 case KRL_SECTION_CERT_SERIAL_LIST:
462 cost_bitmap_restart = cost_bitmap = 8 + 64;
464 case KRL_SECTION_CERT_SERIAL_BITMAP:
466 cost_bitmap_restart = 8 + 64;
468 case KRL_SECTION_CERT_SERIAL_RANGE:
470 cost_bitmap_restart = cost_bitmap = 8 + 64;
474 /* Estimate base cost in bits of each section type */
475 cost_list += 64 * contig + (final ? 0 : 8+64);
476 cost_range += (2 * 64) + (final ? 0 : 8+64);
477 cost_bitmap += last_gap + contig + (final ? 0 : MIN(next_gap, 8+64));
478 cost_bitmap_restart += contig + (final ? 0 : MIN(next_gap, 8+64));
480 /* Convert to byte costs for actual comparison */
481 cost_list = (cost_list + 7) / 8;
482 cost_bitmap = (cost_bitmap + 7) / 8;
483 cost_bitmap_restart = (cost_bitmap_restart + 7) / 8;
484 cost_range = (cost_range + 7) / 8;
486 /* Now pick the best choice */
487 *force_new_section = 0;
488 new_state = KRL_SECTION_CERT_SERIAL_BITMAP;
490 if (cost_range < cost) {
491 new_state = KRL_SECTION_CERT_SERIAL_RANGE;
494 if (cost_list < cost) {
495 new_state = KRL_SECTION_CERT_SERIAL_LIST;
498 if (cost_bitmap_restart < cost) {
499 new_state = KRL_SECTION_CERT_SERIAL_BITMAP;
500 *force_new_section = 1;
501 cost = cost_bitmap_restart;
503 debug3("%s: contig %llu last_gap %llu next_gap %llu final %d, costs:"
504 "list %llu range %llu bitmap %llu new bitmap %llu, "
505 "selected 0x%02x%s", __func__, contig, last_gap, next_gap, final,
506 cost_list, cost_range, cost_bitmap, cost_bitmap_restart, new_state,
507 *force_new_section ? " restart" : "");
511 /* Generate a KRL_SECTION_CERTIFICATES KRL section */
513 revoked_certs_generate(struct revoked_certs *rc, Buffer *buf)
515 int final, force_new_sect, r = -1;
516 u_int64_t i, contig, gap, last = 0, bitmap_start = 0;
517 struct revoked_serial *rs, *nrs;
518 struct revoked_key_id *rki;
519 int next_state, state = 0;
521 u_char *kblob = NULL;
523 BIGNUM *bitmap = NULL;
525 /* Prepare CA scope key blob if we have one supplied */
526 if (key_to_blob(rc->ca_key, &kblob, &klen) == 0)
531 /* Store the header */
532 buffer_put_string(buf, kblob, klen);
533 buffer_put_string(buf, NULL, 0); /* Reserved */
537 /* Store the revoked serials. */
538 for (rs = RB_MIN(revoked_serial_tree, &rc->revoked_serials);
540 rs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs)) {
541 debug3("%s: serial %llu:%llu state 0x%02x", __func__,
542 rs->lo, rs->hi, state);
544 /* Check contiguous length and gap to next section (if any) */
545 nrs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs);
547 gap = nrs == NULL ? 0 : nrs->lo - rs->hi;
548 contig = 1 + (rs->hi - rs->lo);
550 /* Choose next state based on these */
551 next_state = choose_next_state(state, contig, final,
552 state == 0 ? 0 : rs->lo - last, gap, &force_new_sect);
555 * If the current section is a range section or has a different
556 * type to the next section, then finish it off now.
558 if (state != 0 && (force_new_sect || next_state != state ||
559 state == KRL_SECTION_CERT_SERIAL_RANGE)) {
560 debug3("%s: finish state 0x%02x", __func__, state);
562 case KRL_SECTION_CERT_SERIAL_LIST:
563 case KRL_SECTION_CERT_SERIAL_RANGE:
565 case KRL_SECTION_CERT_SERIAL_BITMAP:
566 buffer_put_bignum2(§, bitmap);
571 buffer_put_char(buf, state);
572 buffer_put_string(buf,
573 buffer_ptr(§), buffer_len(§));
576 /* If we are starting a new section then prepare it now */
577 if (next_state != state || force_new_sect) {
578 debug3("%s: start state 0x%02x", __func__, next_state);
582 case KRL_SECTION_CERT_SERIAL_LIST:
583 case KRL_SECTION_CERT_SERIAL_RANGE:
585 case KRL_SECTION_CERT_SERIAL_BITMAP:
586 if ((bitmap = BN_new()) == NULL)
588 bitmap_start = rs->lo;
589 buffer_put_int64(§, bitmap_start);
594 /* Perform section-specific processing */
596 case KRL_SECTION_CERT_SERIAL_LIST:
597 for (i = 0; i < contig; i++)
598 buffer_put_int64(§, rs->lo + i);
600 case KRL_SECTION_CERT_SERIAL_RANGE:
601 buffer_put_int64(§, rs->lo);
602 buffer_put_int64(§, rs->hi);
604 case KRL_SECTION_CERT_SERIAL_BITMAP:
605 if (rs->lo - bitmap_start > INT_MAX) {
606 error("%s: insane bitmap gap", __func__);
609 for (i = 0; i < contig; i++) {
610 if (BN_set_bit(bitmap,
611 rs->lo + i - bitmap_start) != 1)
618 /* Flush the remaining section, if any */
620 debug3("%s: serial final flush for state 0x%02x",
623 case KRL_SECTION_CERT_SERIAL_LIST:
624 case KRL_SECTION_CERT_SERIAL_RANGE:
626 case KRL_SECTION_CERT_SERIAL_BITMAP:
627 buffer_put_bignum2(§, bitmap);
632 buffer_put_char(buf, state);
633 buffer_put_string(buf,
634 buffer_ptr(§), buffer_len(§));
636 debug3("%s: serial done ", __func__);
638 /* Now output a section for any revocations by key ID */
640 RB_FOREACH(rki, revoked_key_id_tree, &rc->revoked_key_ids) {
641 debug3("%s: key ID %s", __func__, rki->key_id);
642 buffer_put_cstring(§, rki->key_id);
644 if (buffer_len(§) != 0) {
645 buffer_put_char(buf, KRL_SECTION_CERT_KEY_ID);
646 buffer_put_string(buf, buffer_ptr(§),
658 ssh_krl_to_blob(struct ssh_krl *krl, Buffer *buf, const Key **sign_keys,
662 struct revoked_certs *rc;
663 struct revoked_blob *rb;
665 u_char *kblob = NULL, *sblob = NULL;
668 if (krl->generated_date == 0)
669 krl->generated_date = time(NULL);
673 /* Store the header */
674 buffer_append(buf, KRL_MAGIC, sizeof(KRL_MAGIC) - 1);
675 buffer_put_int(buf, KRL_FORMAT_VERSION);
676 buffer_put_int64(buf, krl->krl_version);
677 buffer_put_int64(buf, krl->generated_date);
678 buffer_put_int64(buf, krl->flags);
679 buffer_put_string(buf, NULL, 0);
680 buffer_put_cstring(buf, krl->comment ? krl->comment : "");
682 /* Store sections for revoked certificates */
683 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) {
684 if (revoked_certs_generate(rc, §) != 0)
686 buffer_put_char(buf, KRL_SECTION_CERTIFICATES);
687 buffer_put_string(buf, buffer_ptr(§),
691 /* Finally, output sections for revocations by public key/hash */
693 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_keys) {
694 debug3("%s: key len %u ", __func__, rb->len);
695 buffer_put_string(§, rb->blob, rb->len);
697 if (buffer_len(§) != 0) {
698 buffer_put_char(buf, KRL_SECTION_EXPLICIT_KEY);
699 buffer_put_string(buf, buffer_ptr(§),
703 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha1s) {
704 debug3("%s: hash len %u ", __func__, rb->len);
705 buffer_put_string(§, rb->blob, rb->len);
707 if (buffer_len(§) != 0) {
708 buffer_put_char(buf, KRL_SECTION_FINGERPRINT_SHA1);
709 buffer_put_string(buf, buffer_ptr(§),
713 for (i = 0; i < nsign_keys; i++) {
714 if (key_to_blob(sign_keys[i], &kblob, &klen) == 0)
717 debug3("%s: signature key len %u", __func__, klen);
718 buffer_put_char(buf, KRL_SECTION_SIGNATURE);
719 buffer_put_string(buf, kblob, klen);
721 if (key_sign(sign_keys[i], &sblob, &slen,
722 buffer_ptr(buf), buffer_len(buf)) == -1)
724 debug3("%s: signature sig len %u", __func__, slen);
725 buffer_put_string(buf, sblob, slen);
737 format_timestamp(u_int64_t timestamp, char *ts, size_t nts)
745 strftime(ts, nts, "%Y%m%dT%H%M%S", tm);
749 parse_revoked_certs(Buffer *buf, struct ssh_krl *krl)
755 u_int64_t serial, serial_lo, serial_hi;
756 BIGNUM *bitmap = NULL;
760 buffer_init(&subsect);
762 if ((blob = buffer_get_string_ptr_ret(buf, &blen)) == NULL ||
763 buffer_get_string_ptr_ret(buf, NULL) == NULL) { /* reserved */
764 error("%s: buffer error", __func__);
767 if ((ca_key = key_from_blob(blob, blen)) == NULL)
770 while (buffer_len(buf) > 0) {
771 if (buffer_get_char_ret(&type, buf) != 0 ||
772 (blob = buffer_get_string_ptr_ret(buf, &blen)) == NULL) {
773 error("%s: buffer error", __func__);
776 buffer_clear(&subsect);
777 buffer_append(&subsect, blob, blen);
778 debug3("%s: subsection type 0x%02x", __func__, type);
779 /* buffer_dump(&subsect); */
782 case KRL_SECTION_CERT_SERIAL_LIST:
783 while (buffer_len(&subsect) > 0) {
784 if (buffer_get_int64_ret(&serial,
786 error("%s: buffer error", __func__);
789 if (ssh_krl_revoke_cert_by_serial(krl, ca_key,
791 error("%s: update failed", __func__);
796 case KRL_SECTION_CERT_SERIAL_RANGE:
797 if (buffer_get_int64_ret(&serial_lo, &subsect) != 0 ||
798 buffer_get_int64_ret(&serial_hi, &subsect) != 0) {
799 error("%s: buffer error", __func__);
802 if (ssh_krl_revoke_cert_by_serial_range(krl, ca_key,
803 serial_lo, serial_hi) != 0) {
804 error("%s: update failed", __func__);
808 case KRL_SECTION_CERT_SERIAL_BITMAP:
809 if ((bitmap = BN_new()) == NULL) {
810 error("%s: BN_new", __func__);
813 if (buffer_get_int64_ret(&serial_lo, &subsect) != 0 ||
814 buffer_get_bignum2_ret(&subsect, bitmap) != 0) {
815 error("%s: buffer error", __func__);
818 if ((nbits = BN_num_bits(bitmap)) < 0) {
819 error("%s: bitmap bits < 0", __func__);
822 for (serial = 0; serial < (u_int)nbits; serial++) {
823 if (serial > 0 && serial_lo + serial == 0) {
824 error("%s: bitmap wraps u64", __func__);
827 if (!BN_is_bit_set(bitmap, serial))
829 if (ssh_krl_revoke_cert_by_serial(krl, ca_key,
830 serial_lo + serial) != 0) {
831 error("%s: update failed", __func__);
838 case KRL_SECTION_CERT_KEY_ID:
839 while (buffer_len(&subsect) > 0) {
840 if ((key_id = buffer_get_cstring_ret(&subsect,
842 error("%s: buffer error", __func__);
845 if (ssh_krl_revoke_cert_by_key_id(krl, ca_key,
847 error("%s: update failed", __func__);
855 error("Unsupported KRL certificate section %u", type);
858 if (buffer_len(&subsect) > 0) {
859 error("KRL certificate section contains unparsed data");
871 buffer_free(&subsect);
876 /* Attempt to parse a KRL, checking its signature (if any) with sign_ca_keys. */
878 ssh_krl_from_blob(Buffer *buf, struct ssh_krl **krlp,
879 const Key **sign_ca_keys, u_int nsign_ca_keys)
884 int ret = -1, r, sig_seen;
885 Key *key = NULL, **ca_used = NULL;
887 u_int i, j, sig_off, sects_off, blen, format_version, nca_used = 0;
890 if (buffer_len(buf) < sizeof(KRL_MAGIC) - 1 ||
891 memcmp(buffer_ptr(buf), KRL_MAGIC, sizeof(KRL_MAGIC) - 1) != 0) {
892 debug3("%s: not a KRL", __func__);
894 * Return success but a NULL *krlp here to signal that the
895 * file might be a simple list of keys.
900 /* Take a copy of the KRL buffer so we can verify its signature later */
902 buffer_append(©, buffer_ptr(buf), buffer_len(buf));
905 buffer_consume(©, sizeof(KRL_MAGIC) - 1);
907 if ((krl = ssh_krl_init()) == NULL) {
908 error("%s: alloc failed", __func__);
912 if (buffer_get_int_ret(&format_version, ©) != 0) {
913 error("%s: KRL truncated", __func__);
916 if (format_version != KRL_FORMAT_VERSION) {
917 error("%s: KRL unsupported format version %u",
918 __func__, format_version);
921 if (buffer_get_int64_ret(&krl->krl_version, ©) != 0 ||
922 buffer_get_int64_ret(&krl->generated_date, ©) != 0 ||
923 buffer_get_int64_ret(&krl->flags, ©) != 0 ||
924 buffer_get_string_ptr_ret(©, NULL) == NULL || /* reserved */
925 (krl->comment = buffer_get_cstring_ret(©, NULL)) == NULL) {
926 error("%s: buffer error", __func__);
930 format_timestamp(krl->generated_date, timestamp, sizeof(timestamp));
931 debug("KRL version %llu generated at %s%s%s", krl->krl_version,
932 timestamp, *krl->comment ? ": " : "", krl->comment);
935 * 1st pass: verify signatures, if any. This is done to avoid
936 * detailed parsing of data whose provenance is unverified.
939 sects_off = buffer_len(buf) - buffer_len(©);
940 while (buffer_len(©) > 0) {
941 if (buffer_get_char_ret(&type, ©) != 0 ||
942 (blob = buffer_get_string_ptr_ret(©, &blen)) == NULL) {
943 error("%s: buffer error", __func__);
946 debug3("%s: first pass, section 0x%02x", __func__, type);
947 if (type != KRL_SECTION_SIGNATURE) {
949 error("KRL contains non-signature section "
953 /* Not interested for now. */
957 /* First string component is the signing key */
958 if ((key = key_from_blob(blob, blen)) == NULL) {
959 error("%s: invalid signature key", __func__);
962 sig_off = buffer_len(buf) - buffer_len(©);
963 /* Second string component is the signature itself */
964 if ((blob = buffer_get_string_ptr_ret(©, &blen)) == NULL) {
965 error("%s: buffer error", __func__);
968 /* Check signature over entire KRL up to this point */
969 if (key_verify(key, blob, blen,
970 buffer_ptr(buf), buffer_len(buf) - sig_off) == -1) {
971 error("bad signaure on KRL");
974 /* Check if this key has already signed this KRL */
975 for (i = 0; i < nca_used; i++) {
976 if (key_equal(ca_used[i], key)) {
977 error("KRL signed more than once with "
982 /* Record keys used to sign the KRL */
983 ca_used = xrealloc(ca_used, nca_used + 1, sizeof(*ca_used));
984 ca_used[nca_used++] = key;
990 * 2nd pass: parse and load the KRL, skipping the header to the point
991 * where the section start.
993 buffer_append(©, (u_char*)buffer_ptr(buf) + sects_off,
994 buffer_len(buf) - sects_off);
995 while (buffer_len(©) > 0) {
996 if (buffer_get_char_ret(&type, ©) != 0 ||
997 (blob = buffer_get_string_ptr_ret(©, &blen)) == NULL) {
998 error("%s: buffer error", __func__);
1001 debug3("%s: second pass, section 0x%02x", __func__, type);
1002 buffer_clear(§);
1003 buffer_append(§, blob, blen);
1006 case KRL_SECTION_CERTIFICATES:
1007 if ((r = parse_revoked_certs(§, krl)) != 0)
1010 case KRL_SECTION_EXPLICIT_KEY:
1011 case KRL_SECTION_FINGERPRINT_SHA1:
1012 while (buffer_len(§) > 0) {
1013 if ((blob = buffer_get_string_ret(§,
1015 error("%s: buffer error", __func__);
1018 if (type == KRL_SECTION_FINGERPRINT_SHA1 &&
1020 error("%s: bad SHA1 length", __func__);
1024 type == KRL_SECTION_EXPLICIT_KEY ?
1025 &krl->revoked_keys : &krl->revoked_sha1s,
1027 goto out; /* revoke_blob frees blob */
1030 case KRL_SECTION_SIGNATURE:
1031 /* Handled above, but still need to stay in synch */
1032 buffer_clear(§);
1033 if ((blob = buffer_get_string_ptr_ret(©,
1035 error("%s: buffer error", __func__);
1040 error("Unsupported KRL section %u", type);
1043 if (buffer_len(§) > 0) {
1044 error("KRL section contains unparsed data");
1049 /* Check that the key(s) used to sign the KRL weren't revoked */
1051 for (i = 0; i < nca_used; i++) {
1052 if (ssh_krl_check_key(krl, ca_used[i]) == 0)
1055 key_free(ca_used[i]);
1059 if (nca_used && !sig_seen) {
1060 error("All keys used to sign KRL were revoked");
1064 /* If we have CA keys, then verify that one was used to sign the KRL */
1065 if (sig_seen && nsign_ca_keys != 0) {
1067 for (i = 0; !sig_seen && i < nsign_ca_keys; i++) {
1068 for (j = 0; j < nca_used; j++) {
1069 if (ca_used[j] == NULL)
1071 if (key_equal(ca_used[j], sign_ca_keys[i])) {
1078 error("KRL not signed with any trusted key");
1088 for (i = 0; i < nca_used; i++) {
1089 if (ca_used[i] != NULL)
1090 key_free(ca_used[i]);
1100 /* Checks whether a given key/cert is revoked. Does not check its CA */
1102 is_key_revoked(struct ssh_krl *krl, const Key *key)
1104 struct revoked_blob rb, *erb;
1105 struct revoked_serial rs, *ers;
1106 struct revoked_key_id rki, *erki;
1107 struct revoked_certs *rc;
1109 /* Check explicitly revoked hashes first */
1110 bzero(&rb, sizeof(rb));
1111 if ((rb.blob = key_fingerprint_raw(key, SSH_FP_SHA1, &rb.len)) == NULL)
1113 erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha1s, &rb);
1116 debug("%s: revoked by key SHA1", __func__);
1120 /* Next, explicit keys */
1121 bzero(&rb, sizeof(rb));
1122 if (plain_key_blob(key, &rb.blob, &rb.len) != 0)
1124 erb = RB_FIND(revoked_blob_tree, &krl->revoked_keys, &rb);
1127 debug("%s: revoked by explicit key", __func__);
1131 if (!key_is_cert(key))
1134 /* Check cert revocation */
1135 if (revoked_certs_for_ca_key(krl, key->cert->signature_key,
1139 return 0; /* No entry for this CA */
1141 /* Check revocation by cert key ID */
1142 bzero(&rki, sizeof(rki));
1143 rki.key_id = key->cert->key_id;
1144 erki = RB_FIND(revoked_key_id_tree, &rc->revoked_key_ids, &rki);
1146 debug("%s: revoked by key ID", __func__);
1151 * Legacy cert formats lack serial numbers. Zero serials numbers
1152 * are ignored (it's the default when the CA doesn't specify one).
1154 if (key_cert_is_legacy(key) || key->cert->serial == 0)
1157 bzero(&rs, sizeof(rs));
1158 rs.lo = rs.hi = key->cert->serial;
1159 ers = RB_FIND(revoked_serial_tree, &rc->revoked_serials, &rs);
1161 KRL_DBG(("%s: %llu matched %llu:%llu", __func__,
1162 key->cert->serial, ers->lo, ers->hi));
1163 debug("%s: revoked by serial", __func__);
1166 KRL_DBG(("%s: %llu no match", __func__, key->cert->serial));
1172 ssh_krl_check_key(struct ssh_krl *krl, const Key *key)
1176 debug2("%s: checking key", __func__);
1177 if ((r = is_key_revoked(krl, key)) != 0)
1179 if (key_is_cert(key)) {
1180 debug2("%s: checking CA key", __func__);
1181 if ((r = is_key_revoked(krl, key->cert->signature_key)) != 0)
1184 debug3("%s: key okay", __func__);
1188 /* Returns 0 on success, -1 on error or key revoked, -2 if path is not a KRL */
1190 ssh_krl_file_contains_key(const char *path, const Key *key)
1193 struct ssh_krl *krl;
1199 if ((fd = open(path, O_RDONLY)) == -1) {
1200 error("open %s: %s", path, strerror(errno));
1201 error("Revoked keys file not accessible - refusing public key "
1205 buffer_init(&krlbuf);
1206 if (!key_load_file(fd, path, &krlbuf)) {
1208 buffer_free(&krlbuf);
1209 error("Revoked keys file not readable - refusing public key "
1214 if (ssh_krl_from_blob(&krlbuf, &krl, NULL, 0) != 0) {
1215 buffer_free(&krlbuf);
1216 error("Invalid KRL, refusing public key "
1220 buffer_free(&krlbuf);
1222 debug3("%s: %s is not a KRL file", __func__, path);
1225 debug2("%s: checking KRL %s", __func__, path);
1226 revoked = ssh_krl_check_key(krl, key) != 0;
1228 return revoked ? -1 : 0;