xref: /freebsd/crypto/openssh/krl.c (revision 1f4bcc459a76b7aa664f3fd557684cd0ba6da352)
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 1.33 2015/07/03 03:43:18 djm Exp $ */
18 
19 #include "includes.h"
20 
21 #include <sys/param.h>	/* MIN */
22 #include <sys/types.h>
23 #include <openbsd-compat/sys-tree.h>
24 #include <openbsd-compat/sys-queue.h>
25 
26 #include <errno.h>
27 #include <fcntl.h>
28 #include <limits.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 
42 #include "krl.h"
43 
44 /* #define DEBUG_KRL */
45 #ifdef DEBUG_KRL
46 # define KRL_DBG(x) debug3 x
47 #else
48 # define KRL_DBG(x)
49 #endif
50 
51 /*
52  * Trees of revoked serial numbers, key IDs and keys. This allows
53  * quick searching, querying and producing lists in canonical order.
54  */
55 
56 /* Tree of serial numbers. XXX make smarter: really need a real sparse bitmap */
57 struct revoked_serial {
58 	u_int64_t lo, hi;
59 	RB_ENTRY(revoked_serial) tree_entry;
60 };
61 static int serial_cmp(struct revoked_serial *a, struct revoked_serial *b);
62 RB_HEAD(revoked_serial_tree, revoked_serial);
63 RB_GENERATE_STATIC(revoked_serial_tree, revoked_serial, tree_entry, serial_cmp);
64 
65 /* Tree of key IDs */
66 struct revoked_key_id {
67 	char *key_id;
68 	RB_ENTRY(revoked_key_id) tree_entry;
69 };
70 static int key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b);
71 RB_HEAD(revoked_key_id_tree, revoked_key_id);
72 RB_GENERATE_STATIC(revoked_key_id_tree, revoked_key_id, tree_entry, key_id_cmp);
73 
74 /* Tree of blobs (used for keys and fingerprints) */
75 struct revoked_blob {
76 	u_char *blob;
77 	size_t len;
78 	RB_ENTRY(revoked_blob) tree_entry;
79 };
80 static int blob_cmp(struct revoked_blob *a, struct revoked_blob *b);
81 RB_HEAD(revoked_blob_tree, revoked_blob);
82 RB_GENERATE_STATIC(revoked_blob_tree, revoked_blob, tree_entry, blob_cmp);
83 
84 /* Tracks revoked certs for a single CA */
85 struct revoked_certs {
86 	struct sshkey *ca_key;
87 	struct revoked_serial_tree revoked_serials;
88 	struct revoked_key_id_tree revoked_key_ids;
89 	TAILQ_ENTRY(revoked_certs) entry;
90 };
91 TAILQ_HEAD(revoked_certs_list, revoked_certs);
92 
93 struct ssh_krl {
94 	u_int64_t krl_version;
95 	u_int64_t generated_date;
96 	u_int64_t flags;
97 	char *comment;
98 	struct revoked_blob_tree revoked_keys;
99 	struct revoked_blob_tree revoked_sha1s;
100 	struct revoked_certs_list revoked_certs;
101 };
102 
103 /* Return equal if a and b overlap */
104 static int
105 serial_cmp(struct revoked_serial *a, struct revoked_serial *b)
106 {
107 	if (a->hi >= b->lo && a->lo <= b->hi)
108 		return 0;
109 	return a->lo < b->lo ? -1 : 1;
110 }
111 
112 static int
113 key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b)
114 {
115 	return strcmp(a->key_id, b->key_id);
116 }
117 
118 static int
119 blob_cmp(struct revoked_blob *a, struct revoked_blob *b)
120 {
121 	int r;
122 
123 	if (a->len != b->len) {
124 		if ((r = memcmp(a->blob, b->blob, MIN(a->len, b->len))) != 0)
125 			return r;
126 		return a->len > b->len ? 1 : -1;
127 	} else
128 		return memcmp(a->blob, b->blob, a->len);
129 }
130 
131 struct ssh_krl *
132 ssh_krl_init(void)
133 {
134 	struct ssh_krl *krl;
135 
136 	if ((krl = calloc(1, sizeof(*krl))) == NULL)
137 		return NULL;
138 	RB_INIT(&krl->revoked_keys);
139 	RB_INIT(&krl->revoked_sha1s);
140 	TAILQ_INIT(&krl->revoked_certs);
141 	return krl;
142 }
143 
144 static void
145 revoked_certs_free(struct revoked_certs *rc)
146 {
147 	struct revoked_serial *rs, *trs;
148 	struct revoked_key_id *rki, *trki;
149 
150 	RB_FOREACH_SAFE(rs, revoked_serial_tree, &rc->revoked_serials, trs) {
151 		RB_REMOVE(revoked_serial_tree, &rc->revoked_serials, rs);
152 		free(rs);
153 	}
154 	RB_FOREACH_SAFE(rki, revoked_key_id_tree, &rc->revoked_key_ids, trki) {
155 		RB_REMOVE(revoked_key_id_tree, &rc->revoked_key_ids, rki);
156 		free(rki->key_id);
157 		free(rki);
158 	}
159 	sshkey_free(rc->ca_key);
160 }
161 
162 void
163 ssh_krl_free(struct ssh_krl *krl)
164 {
165 	struct revoked_blob *rb, *trb;
166 	struct revoked_certs *rc, *trc;
167 
168 	if (krl == NULL)
169 		return;
170 
171 	free(krl->comment);
172 	RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_keys, trb) {
173 		RB_REMOVE(revoked_blob_tree, &krl->revoked_keys, rb);
174 		free(rb->blob);
175 		free(rb);
176 	}
177 	RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha1s, trb) {
178 		RB_REMOVE(revoked_blob_tree, &krl->revoked_sha1s, rb);
179 		free(rb->blob);
180 		free(rb);
181 	}
182 	TAILQ_FOREACH_SAFE(rc, &krl->revoked_certs, entry, trc) {
183 		TAILQ_REMOVE(&krl->revoked_certs, rc, entry);
184 		revoked_certs_free(rc);
185 	}
186 }
187 
188 void
189 ssh_krl_set_version(struct ssh_krl *krl, u_int64_t version)
190 {
191 	krl->krl_version = version;
192 }
193 
194 int
195 ssh_krl_set_comment(struct ssh_krl *krl, const char *comment)
196 {
197 	free(krl->comment);
198 	if ((krl->comment = strdup(comment)) == NULL)
199 		return SSH_ERR_ALLOC_FAIL;
200 	return 0;
201 }
202 
203 /*
204  * Find the revoked_certs struct for a CA key. If allow_create is set then
205  * create a new one in the tree if one did not exist already.
206  */
207 static int
208 revoked_certs_for_ca_key(struct ssh_krl *krl, const struct sshkey *ca_key,
209     struct revoked_certs **rcp, int allow_create)
210 {
211 	struct revoked_certs *rc;
212 	int r;
213 
214 	*rcp = NULL;
215 	TAILQ_FOREACH(rc, &krl->revoked_certs, entry) {
216 		if ((ca_key == NULL && rc->ca_key == NULL) ||
217 		    sshkey_equal(rc->ca_key, ca_key)) {
218 			*rcp = rc;
219 			return 0;
220 		}
221 	}
222 	if (!allow_create)
223 		return 0;
224 	/* If this CA doesn't exist in the list then add it now */
225 	if ((rc = calloc(1, sizeof(*rc))) == NULL)
226 		return SSH_ERR_ALLOC_FAIL;
227 	if (ca_key == NULL)
228 		rc->ca_key = NULL;
229 	else if ((r = sshkey_from_private(ca_key, &rc->ca_key)) != 0) {
230 		free(rc);
231 		return r;
232 	}
233 	RB_INIT(&rc->revoked_serials);
234 	RB_INIT(&rc->revoked_key_ids);
235 	TAILQ_INSERT_TAIL(&krl->revoked_certs, rc, entry);
236 	KRL_DBG(("%s: new CA %s", __func__,
237 	    ca_key == NULL ? "*" : sshkey_type(ca_key)));
238 	*rcp = rc;
239 	return 0;
240 }
241 
242 static int
243 insert_serial_range(struct revoked_serial_tree *rt, u_int64_t lo, u_int64_t hi)
244 {
245 	struct revoked_serial rs, *ers, *crs, *irs;
246 
247 	KRL_DBG(("%s: insert %llu:%llu", __func__, lo, hi));
248 	memset(&rs, 0, sizeof(rs));
249 	rs.lo = lo;
250 	rs.hi = hi;
251 	ers = RB_NFIND(revoked_serial_tree, rt, &rs);
252 	if (ers == NULL || serial_cmp(ers, &rs) != 0) {
253 		/* No entry matches. Just insert */
254 		if ((irs = malloc(sizeof(rs))) == NULL)
255 			return SSH_ERR_ALLOC_FAIL;
256 		memcpy(irs, &rs, sizeof(*irs));
257 		ers = RB_INSERT(revoked_serial_tree, rt, irs);
258 		if (ers != NULL) {
259 			KRL_DBG(("%s: bad: ers != NULL", __func__));
260 			/* Shouldn't happen */
261 			free(irs);
262 			return SSH_ERR_INTERNAL_ERROR;
263 		}
264 		ers = irs;
265 	} else {
266 		KRL_DBG(("%s: overlap found %llu:%llu", __func__,
267 		    ers->lo, ers->hi));
268 		/*
269 		 * The inserted entry overlaps an existing one. Grow the
270 		 * existing entry.
271 		 */
272 		if (ers->lo > lo)
273 			ers->lo = lo;
274 		if (ers->hi < hi)
275 			ers->hi = hi;
276 	}
277 
278 	/*
279 	 * The inserted or revised range might overlap or abut adjacent ones;
280 	 * coalesce as necessary.
281 	 */
282 
283 	/* Check predecessors */
284 	while ((crs = RB_PREV(revoked_serial_tree, rt, ers)) != NULL) {
285 		KRL_DBG(("%s: pred %llu:%llu", __func__, crs->lo, crs->hi));
286 		if (ers->lo != 0 && crs->hi < ers->lo - 1)
287 			break;
288 		/* This entry overlaps. */
289 		if (crs->lo < ers->lo) {
290 			ers->lo = crs->lo;
291 			KRL_DBG(("%s: pred extend %llu:%llu", __func__,
292 			    ers->lo, ers->hi));
293 		}
294 		RB_REMOVE(revoked_serial_tree, rt, crs);
295 		free(crs);
296 	}
297 	/* Check successors */
298 	while ((crs = RB_NEXT(revoked_serial_tree, rt, ers)) != NULL) {
299 		KRL_DBG(("%s: succ %llu:%llu", __func__, crs->lo, crs->hi));
300 		if (ers->hi != (u_int64_t)-1 && crs->lo > ers->hi + 1)
301 			break;
302 		/* This entry overlaps. */
303 		if (crs->hi > ers->hi) {
304 			ers->hi = crs->hi;
305 			KRL_DBG(("%s: succ extend %llu:%llu", __func__,
306 			    ers->lo, ers->hi));
307 		}
308 		RB_REMOVE(revoked_serial_tree, rt, crs);
309 		free(crs);
310 	}
311 	KRL_DBG(("%s: done, final %llu:%llu", __func__, ers->lo, ers->hi));
312 	return 0;
313 }
314 
315 int
316 ssh_krl_revoke_cert_by_serial(struct ssh_krl *krl, const struct sshkey *ca_key,
317     u_int64_t serial)
318 {
319 	return ssh_krl_revoke_cert_by_serial_range(krl, ca_key, serial, serial);
320 }
321 
322 int
323 ssh_krl_revoke_cert_by_serial_range(struct ssh_krl *krl,
324     const struct sshkey *ca_key, u_int64_t lo, u_int64_t hi)
325 {
326 	struct revoked_certs *rc;
327 	int r;
328 
329 	if (lo > hi || lo == 0)
330 		return SSH_ERR_INVALID_ARGUMENT;
331 	if ((r = revoked_certs_for_ca_key(krl, ca_key, &rc, 1)) != 0)
332 		return r;
333 	return insert_serial_range(&rc->revoked_serials, lo, hi);
334 }
335 
336 int
337 ssh_krl_revoke_cert_by_key_id(struct ssh_krl *krl, const struct sshkey *ca_key,
338     const char *key_id)
339 {
340 	struct revoked_key_id *rki, *erki;
341 	struct revoked_certs *rc;
342 	int r;
343 
344 	if ((r = revoked_certs_for_ca_key(krl, ca_key, &rc, 1)) != 0)
345 		return r;
346 
347 	KRL_DBG(("%s: revoke %s", __func__, key_id));
348 	if ((rki = calloc(1, sizeof(*rki))) == NULL ||
349 	    (rki->key_id = strdup(key_id)) == NULL) {
350 		free(rki);
351 		return SSH_ERR_ALLOC_FAIL;
352 	}
353 	erki = RB_INSERT(revoked_key_id_tree, &rc->revoked_key_ids, rki);
354 	if (erki != NULL) {
355 		free(rki->key_id);
356 		free(rki);
357 	}
358 	return 0;
359 }
360 
361 /* Convert "key" to a public key blob without any certificate information */
362 static int
363 plain_key_blob(const struct sshkey *key, u_char **blob, size_t *blen)
364 {
365 	struct sshkey *kcopy;
366 	int r;
367 
368 	if ((r = sshkey_from_private(key, &kcopy)) != 0)
369 		return r;
370 	if (sshkey_is_cert(kcopy)) {
371 		if ((r = sshkey_drop_cert(kcopy)) != 0) {
372 			sshkey_free(kcopy);
373 			return r;
374 		}
375 	}
376 	r = sshkey_to_blob(kcopy, blob, blen);
377 	sshkey_free(kcopy);
378 	return r;
379 }
380 
381 /* Revoke a key blob. Ownership of blob is transferred to the tree */
382 static int
383 revoke_blob(struct revoked_blob_tree *rbt, u_char *blob, size_t len)
384 {
385 	struct revoked_blob *rb, *erb;
386 
387 	if ((rb = calloc(1, sizeof(*rb))) == NULL)
388 		return SSH_ERR_ALLOC_FAIL;
389 	rb->blob = blob;
390 	rb->len = len;
391 	erb = RB_INSERT(revoked_blob_tree, rbt, rb);
392 	if (erb != NULL) {
393 		free(rb->blob);
394 		free(rb);
395 	}
396 	return 0;
397 }
398 
399 int
400 ssh_krl_revoke_key_explicit(struct ssh_krl *krl, const struct sshkey *key)
401 {
402 	u_char *blob;
403 	size_t len;
404 	int r;
405 
406 	debug3("%s: revoke type %s", __func__, sshkey_type(key));
407 	if ((r = plain_key_blob(key, &blob, &len)) != 0)
408 		return r;
409 	return revoke_blob(&krl->revoked_keys, blob, len);
410 }
411 
412 int
413 ssh_krl_revoke_key_sha1(struct ssh_krl *krl, const struct sshkey *key)
414 {
415 	u_char *blob;
416 	size_t len;
417 	int r;
418 
419 	debug3("%s: revoke type %s by sha1", __func__, sshkey_type(key));
420 	if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA1,
421 	    &blob, &len)) != 0)
422 		return r;
423 	return revoke_blob(&krl->revoked_sha1s, blob, len);
424 }
425 
426 int
427 ssh_krl_revoke_key(struct ssh_krl *krl, const struct sshkey *key)
428 {
429 	if (!sshkey_is_cert(key))
430 		return ssh_krl_revoke_key_sha1(krl, key);
431 
432 	if (key->cert->serial == 0) {
433 		return ssh_krl_revoke_cert_by_key_id(krl,
434 		    key->cert->signature_key,
435 		    key->cert->key_id);
436 	} else {
437 		return ssh_krl_revoke_cert_by_serial(krl,
438 		    key->cert->signature_key,
439 		    key->cert->serial);
440 	}
441 }
442 
443 /*
444  * Select the most compact section type to emit next in a KRL based on
445  * the current section type, the run length of contiguous revoked serial
446  * numbers and the gaps from the last and to the next revoked serial.
447  * Applies a mostly-accurate bit cost model to select the section type
448  * that will minimise the size of the resultant KRL.
449  */
450 static int
451 choose_next_state(int current_state, u_int64_t contig, int final,
452     u_int64_t last_gap, u_int64_t next_gap, int *force_new_section)
453 {
454 	int new_state;
455 	u_int64_t cost, cost_list, cost_range, cost_bitmap, cost_bitmap_restart;
456 
457 	/*
458 	 * Avoid unsigned overflows.
459 	 * The limits are high enough to avoid confusing the calculations.
460 	 */
461 	contig = MIN(contig, 1ULL<<31);
462 	last_gap = MIN(last_gap, 1ULL<<31);
463 	next_gap = MIN(next_gap, 1ULL<<31);
464 
465 	/*
466 	 * Calculate the cost to switch from the current state to candidates.
467 	 * NB. range sections only ever contain a single range, so their
468 	 * switching cost is independent of the current_state.
469 	 */
470 	cost_list = cost_bitmap = cost_bitmap_restart = 0;
471 	cost_range = 8;
472 	switch (current_state) {
473 	case KRL_SECTION_CERT_SERIAL_LIST:
474 		cost_bitmap_restart = cost_bitmap = 8 + 64;
475 		break;
476 	case KRL_SECTION_CERT_SERIAL_BITMAP:
477 		cost_list = 8;
478 		cost_bitmap_restart = 8 + 64;
479 		break;
480 	case KRL_SECTION_CERT_SERIAL_RANGE:
481 	case 0:
482 		cost_bitmap_restart = cost_bitmap = 8 + 64;
483 		cost_list = 8;
484 	}
485 
486 	/* Estimate base cost in bits of each section type */
487 	cost_list += 64 * contig + (final ? 0 : 8+64);
488 	cost_range += (2 * 64) + (final ? 0 : 8+64);
489 	cost_bitmap += last_gap + contig + (final ? 0 : MIN(next_gap, 8+64));
490 	cost_bitmap_restart += contig + (final ? 0 : MIN(next_gap, 8+64));
491 
492 	/* Convert to byte costs for actual comparison */
493 	cost_list = (cost_list + 7) / 8;
494 	cost_bitmap = (cost_bitmap + 7) / 8;
495 	cost_bitmap_restart = (cost_bitmap_restart + 7) / 8;
496 	cost_range = (cost_range + 7) / 8;
497 
498 	/* Now pick the best choice */
499 	*force_new_section = 0;
500 	new_state = KRL_SECTION_CERT_SERIAL_BITMAP;
501 	cost = cost_bitmap;
502 	if (cost_range < cost) {
503 		new_state = KRL_SECTION_CERT_SERIAL_RANGE;
504 		cost = cost_range;
505 	}
506 	if (cost_list < cost) {
507 		new_state = KRL_SECTION_CERT_SERIAL_LIST;
508 		cost = cost_list;
509 	}
510 	if (cost_bitmap_restart < cost) {
511 		new_state = KRL_SECTION_CERT_SERIAL_BITMAP;
512 		*force_new_section = 1;
513 		cost = cost_bitmap_restart;
514 	}
515 	KRL_DBG(("%s: contig %llu last_gap %llu next_gap %llu final %d, costs:"
516 	    "list %llu range %llu bitmap %llu new bitmap %llu, "
517 	    "selected 0x%02x%s", __func__, (long long unsigned)contig,
518 	    (long long unsigned)last_gap, (long long unsigned)next_gap, final,
519 	    (long long unsigned)cost_list, (long long unsigned)cost_range,
520 	    (long long unsigned)cost_bitmap,
521 	    (long long unsigned)cost_bitmap_restart, new_state,
522 	    *force_new_section ? " restart" : ""));
523 	return new_state;
524 }
525 
526 static int
527 put_bitmap(struct sshbuf *buf, struct bitmap *bitmap)
528 {
529 	size_t len;
530 	u_char *blob;
531 	int r;
532 
533 	len = bitmap_nbytes(bitmap);
534 	if ((blob = malloc(len)) == NULL)
535 		return SSH_ERR_ALLOC_FAIL;
536 	if (bitmap_to_string(bitmap, blob, len) != 0) {
537 		free(blob);
538 		return SSH_ERR_INTERNAL_ERROR;
539 	}
540 	r = sshbuf_put_bignum2_bytes(buf, blob, len);
541 	free(blob);
542 	return r;
543 }
544 
545 /* Generate a KRL_SECTION_CERTIFICATES KRL section */
546 static int
547 revoked_certs_generate(struct revoked_certs *rc, struct sshbuf *buf)
548 {
549 	int final, force_new_sect, r = SSH_ERR_INTERNAL_ERROR;
550 	u_int64_t i, contig, gap, last = 0, bitmap_start = 0;
551 	struct revoked_serial *rs, *nrs;
552 	struct revoked_key_id *rki;
553 	int next_state, state = 0;
554 	struct sshbuf *sect;
555 	struct bitmap *bitmap = NULL;
556 
557 	if ((sect = sshbuf_new()) == NULL)
558 		return SSH_ERR_ALLOC_FAIL;
559 
560 	/* Store the header: optional CA scope key, reserved */
561 	if (rc->ca_key == NULL) {
562 		if ((r = sshbuf_put_string(buf, NULL, 0)) != 0)
563 			goto out;
564 	} else {
565 		if ((r = sshkey_puts(rc->ca_key, buf)) != 0)
566 			goto out;
567 	}
568 	if ((r = sshbuf_put_string(buf, NULL, 0)) != 0)
569 		goto out;
570 
571 	/* Store the revoked serials.  */
572 	for (rs = RB_MIN(revoked_serial_tree, &rc->revoked_serials);
573 	     rs != NULL;
574 	     rs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs)) {
575 		KRL_DBG(("%s: serial %llu:%llu state 0x%02x", __func__,
576 		    (long long unsigned)rs->lo, (long long unsigned)rs->hi,
577 		    state));
578 
579 		/* Check contiguous length and gap to next section (if any) */
580 		nrs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs);
581 		final = nrs == NULL;
582 		gap = nrs == NULL ? 0 : nrs->lo - rs->hi;
583 		contig = 1 + (rs->hi - rs->lo);
584 
585 		/* Choose next state based on these */
586 		next_state = choose_next_state(state, contig, final,
587 		    state == 0 ? 0 : rs->lo - last, gap, &force_new_sect);
588 
589 		/*
590 		 * If the current section is a range section or has a different
591 		 * type to the next section, then finish it off now.
592 		 */
593 		if (state != 0 && (force_new_sect || next_state != state ||
594 		    state == KRL_SECTION_CERT_SERIAL_RANGE)) {
595 			KRL_DBG(("%s: finish state 0x%02x", __func__, state));
596 			switch (state) {
597 			case KRL_SECTION_CERT_SERIAL_LIST:
598 			case KRL_SECTION_CERT_SERIAL_RANGE:
599 				break;
600 			case KRL_SECTION_CERT_SERIAL_BITMAP:
601 				if ((r = put_bitmap(sect, bitmap)) != 0)
602 					goto out;
603 				bitmap_free(bitmap);
604 				bitmap = NULL;
605 				break;
606 			}
607 			if ((r = sshbuf_put_u8(buf, state)) != 0 ||
608 			    (r = sshbuf_put_stringb(buf, sect)) != 0)
609 				goto out;
610 			sshbuf_reset(sect);
611 		}
612 
613 		/* If we are starting a new section then prepare it now */
614 		if (next_state != state || force_new_sect) {
615 			KRL_DBG(("%s: start state 0x%02x", __func__,
616 			    next_state));
617 			state = next_state;
618 			sshbuf_reset(sect);
619 			switch (state) {
620 			case KRL_SECTION_CERT_SERIAL_LIST:
621 			case KRL_SECTION_CERT_SERIAL_RANGE:
622 				break;
623 			case KRL_SECTION_CERT_SERIAL_BITMAP:
624 				if ((bitmap = bitmap_new()) == NULL) {
625 					r = SSH_ERR_ALLOC_FAIL;
626 					goto out;
627 				}
628 				bitmap_start = rs->lo;
629 				if ((r = sshbuf_put_u64(sect,
630 				    bitmap_start)) != 0)
631 					goto out;
632 				break;
633 			}
634 		}
635 
636 		/* Perform section-specific processing */
637 		switch (state) {
638 		case KRL_SECTION_CERT_SERIAL_LIST:
639 			for (i = 0; i < contig; i++) {
640 				if ((r = sshbuf_put_u64(sect, rs->lo + i)) != 0)
641 					goto out;
642 			}
643 			break;
644 		case KRL_SECTION_CERT_SERIAL_RANGE:
645 			if ((r = sshbuf_put_u64(sect, rs->lo)) != 0 ||
646 			    (r = sshbuf_put_u64(sect, rs->hi)) != 0)
647 				goto out;
648 			break;
649 		case KRL_SECTION_CERT_SERIAL_BITMAP:
650 			if (rs->lo - bitmap_start > INT_MAX) {
651 				error("%s: insane bitmap gap", __func__);
652 				goto out;
653 			}
654 			for (i = 0; i < contig; i++) {
655 				if (bitmap_set_bit(bitmap,
656 				    rs->lo + i - bitmap_start) != 0) {
657 					r = SSH_ERR_ALLOC_FAIL;
658 					goto out;
659 				}
660 			}
661 			break;
662 		}
663 		last = rs->hi;
664 	}
665 	/* Flush the remaining section, if any */
666 	if (state != 0) {
667 		KRL_DBG(("%s: serial final flush for state 0x%02x",
668 		    __func__, state));
669 		switch (state) {
670 		case KRL_SECTION_CERT_SERIAL_LIST:
671 		case KRL_SECTION_CERT_SERIAL_RANGE:
672 			break;
673 		case KRL_SECTION_CERT_SERIAL_BITMAP:
674 			if ((r = put_bitmap(sect, bitmap)) != 0)
675 				goto out;
676 			bitmap_free(bitmap);
677 			bitmap = NULL;
678 			break;
679 		}
680 		if ((r = sshbuf_put_u8(buf, state)) != 0 ||
681 		    (r = sshbuf_put_stringb(buf, sect)) != 0)
682 			goto out;
683 	}
684 	KRL_DBG(("%s: serial done ", __func__));
685 
686 	/* Now output a section for any revocations by key ID */
687 	sshbuf_reset(sect);
688 	RB_FOREACH(rki, revoked_key_id_tree, &rc->revoked_key_ids) {
689 		KRL_DBG(("%s: key ID %s", __func__, rki->key_id));
690 		if ((r = sshbuf_put_cstring(sect, rki->key_id)) != 0)
691 			goto out;
692 	}
693 	if (sshbuf_len(sect) != 0) {
694 		if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERT_KEY_ID)) != 0 ||
695 		    (r = sshbuf_put_stringb(buf, sect)) != 0)
696 			goto out;
697 	}
698 	r = 0;
699  out:
700 	bitmap_free(bitmap);
701 	sshbuf_free(sect);
702 	return r;
703 }
704 
705 int
706 ssh_krl_to_blob(struct ssh_krl *krl, struct sshbuf *buf,
707     const struct sshkey **sign_keys, u_int nsign_keys)
708 {
709 	int r = SSH_ERR_INTERNAL_ERROR;
710 	struct revoked_certs *rc;
711 	struct revoked_blob *rb;
712 	struct sshbuf *sect;
713 	u_char *sblob = NULL;
714 	size_t slen, i;
715 
716 	if (krl->generated_date == 0)
717 		krl->generated_date = time(NULL);
718 
719 	if ((sect = sshbuf_new()) == NULL)
720 		return SSH_ERR_ALLOC_FAIL;
721 
722 	/* Store the header */
723 	if ((r = sshbuf_put(buf, KRL_MAGIC, sizeof(KRL_MAGIC) - 1)) != 0 ||
724 	    (r = sshbuf_put_u32(buf, KRL_FORMAT_VERSION)) != 0 ||
725 	    (r = sshbuf_put_u64(buf, krl->krl_version)) != 0 ||
726 	    (r = sshbuf_put_u64(buf, krl->generated_date) != 0) ||
727 	    (r = sshbuf_put_u64(buf, krl->flags)) != 0 ||
728 	    (r = sshbuf_put_string(buf, NULL, 0)) != 0 ||
729 	    (r = sshbuf_put_cstring(buf, krl->comment)) != 0)
730 		goto out;
731 
732 	/* Store sections for revoked certificates */
733 	TAILQ_FOREACH(rc, &krl->revoked_certs, entry) {
734 		sshbuf_reset(sect);
735 		if ((r = revoked_certs_generate(rc, sect)) != 0)
736 			goto out;
737 		if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERTIFICATES)) != 0 ||
738 		    (r = sshbuf_put_stringb(buf, sect)) != 0)
739 			goto out;
740 	}
741 
742 	/* Finally, output sections for revocations by public key/hash */
743 	sshbuf_reset(sect);
744 	RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_keys) {
745 		KRL_DBG(("%s: key len %zu ", __func__, rb->len));
746 		if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0)
747 			goto out;
748 	}
749 	if (sshbuf_len(sect) != 0) {
750 		if ((r = sshbuf_put_u8(buf, KRL_SECTION_EXPLICIT_KEY)) != 0 ||
751 		    (r = sshbuf_put_stringb(buf, sect)) != 0)
752 			goto out;
753 	}
754 	sshbuf_reset(sect);
755 	RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha1s) {
756 		KRL_DBG(("%s: hash len %zu ", __func__, rb->len));
757 		if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0)
758 			goto out;
759 	}
760 	if (sshbuf_len(sect) != 0) {
761 		if ((r = sshbuf_put_u8(buf,
762 		    KRL_SECTION_FINGERPRINT_SHA1)) != 0 ||
763 		    (r = sshbuf_put_stringb(buf, sect)) != 0)
764 			goto out;
765 	}
766 
767 	for (i = 0; i < nsign_keys; i++) {
768 		KRL_DBG(("%s: signature key %s", __func__,
769 		    sshkey_ssh_name(sign_keys[i])));
770 		if ((r = sshbuf_put_u8(buf, KRL_SECTION_SIGNATURE)) != 0 ||
771 		    (r = sshkey_puts(sign_keys[i], buf)) != 0)
772 			goto out;
773 
774 		if ((r = sshkey_sign(sign_keys[i], &sblob, &slen,
775 		    sshbuf_ptr(buf), sshbuf_len(buf), 0)) != 0)
776 			goto out;
777 		KRL_DBG(("%s: signature sig len %zu", __func__, slen));
778 		if ((r = sshbuf_put_string(buf, sblob, slen)) != 0)
779 			goto out;
780 	}
781 
782 	r = 0;
783  out:
784 	free(sblob);
785 	sshbuf_free(sect);
786 	return r;
787 }
788 
789 static void
790 format_timestamp(u_int64_t timestamp, char *ts, size_t nts)
791 {
792 	time_t t;
793 	struct tm *tm;
794 
795 	t = timestamp;
796 	tm = localtime(&t);
797 	if (tm == NULL)
798 		strlcpy(ts, "<INVALID>", nts);
799 	else {
800 		*ts = '\0';
801 		strftime(ts, nts, "%Y%m%dT%H%M%S", tm);
802 	}
803 }
804 
805 static int
806 parse_revoked_certs(struct sshbuf *buf, struct ssh_krl *krl)
807 {
808 	int r = SSH_ERR_INTERNAL_ERROR;
809 	u_char type;
810 	const u_char *blob;
811 	size_t blen, nbits;
812 	struct sshbuf *subsect = NULL;
813 	u_int64_t serial, serial_lo, serial_hi;
814 	struct bitmap *bitmap = NULL;
815 	char *key_id = NULL;
816 	struct sshkey *ca_key = NULL;
817 
818 	if ((subsect = sshbuf_new()) == NULL)
819 		return SSH_ERR_ALLOC_FAIL;
820 
821 	/* Header: key, reserved */
822 	if ((r = sshbuf_get_string_direct(buf, &blob, &blen)) != 0 ||
823 	    (r = sshbuf_skip_string(buf)) != 0)
824 		goto out;
825 	if (blen != 0 && (r = sshkey_from_blob(blob, blen, &ca_key)) != 0)
826 		goto out;
827 
828 	while (sshbuf_len(buf) > 0) {
829 		if (subsect != NULL) {
830 			sshbuf_free(subsect);
831 			subsect = NULL;
832 		}
833 		if ((r = sshbuf_get_u8(buf, &type)) != 0 ||
834 		    (r = sshbuf_froms(buf, &subsect)) != 0)
835 			goto out;
836 		KRL_DBG(("%s: subsection type 0x%02x", __func__, type));
837 		/* sshbuf_dump(subsect, stderr); */
838 
839 		switch (type) {
840 		case KRL_SECTION_CERT_SERIAL_LIST:
841 			while (sshbuf_len(subsect) > 0) {
842 				if ((r = sshbuf_get_u64(subsect, &serial)) != 0)
843 					goto out;
844 				if ((r = ssh_krl_revoke_cert_by_serial(krl,
845 				    ca_key, serial)) != 0)
846 					goto out;
847 			}
848 			break;
849 		case KRL_SECTION_CERT_SERIAL_RANGE:
850 			if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 ||
851 			    (r = sshbuf_get_u64(subsect, &serial_hi)) != 0)
852 				goto out;
853 			if ((r = ssh_krl_revoke_cert_by_serial_range(krl,
854 			    ca_key, serial_lo, serial_hi)) != 0)
855 				goto out;
856 			break;
857 		case KRL_SECTION_CERT_SERIAL_BITMAP:
858 			if ((bitmap = bitmap_new()) == NULL) {
859 				r = SSH_ERR_ALLOC_FAIL;
860 				goto out;
861 			}
862 			if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 ||
863 			    (r = sshbuf_get_bignum2_bytes_direct(subsect,
864 			    &blob, &blen)) != 0)
865 				goto out;
866 			if (bitmap_from_string(bitmap, blob, blen) != 0) {
867 				r = SSH_ERR_INVALID_FORMAT;
868 				goto out;
869 			}
870 			nbits = bitmap_nbits(bitmap);
871 			for (serial = 0; serial < (u_int64_t)nbits; serial++) {
872 				if (serial > 0 && serial_lo + serial == 0) {
873 					error("%s: bitmap wraps u64", __func__);
874 					r = SSH_ERR_INVALID_FORMAT;
875 					goto out;
876 				}
877 				if (!bitmap_test_bit(bitmap, serial))
878 					continue;
879 				if ((r = ssh_krl_revoke_cert_by_serial(krl,
880 				    ca_key, serial_lo + serial)) != 0)
881 					goto out;
882 			}
883 			bitmap_free(bitmap);
884 			bitmap = NULL;
885 			break;
886 		case KRL_SECTION_CERT_KEY_ID:
887 			while (sshbuf_len(subsect) > 0) {
888 				if ((r = sshbuf_get_cstring(subsect,
889 				    &key_id, NULL)) != 0)
890 					goto out;
891 				if ((r = ssh_krl_revoke_cert_by_key_id(krl,
892 				    ca_key, key_id)) != 0)
893 					goto out;
894 				free(key_id);
895 				key_id = NULL;
896 			}
897 			break;
898 		default:
899 			error("Unsupported KRL certificate section %u", type);
900 			r = SSH_ERR_INVALID_FORMAT;
901 			goto out;
902 		}
903 		if (sshbuf_len(subsect) > 0) {
904 			error("KRL certificate section contains unparsed data");
905 			r = SSH_ERR_INVALID_FORMAT;
906 			goto out;
907 		}
908 	}
909 
910 	r = 0;
911  out:
912 	if (bitmap != NULL)
913 		bitmap_free(bitmap);
914 	free(key_id);
915 	sshkey_free(ca_key);
916 	sshbuf_free(subsect);
917 	return r;
918 }
919 
920 
921 /* Attempt to parse a KRL, checking its signature (if any) with sign_ca_keys. */
922 int
923 ssh_krl_from_blob(struct sshbuf *buf, struct ssh_krl **krlp,
924     const struct sshkey **sign_ca_keys, size_t nsign_ca_keys)
925 {
926 	struct sshbuf *copy = NULL, *sect = NULL;
927 	struct ssh_krl *krl = NULL;
928 	char timestamp[64];
929 	int r = SSH_ERR_INTERNAL_ERROR, sig_seen;
930 	struct sshkey *key = NULL, **ca_used = NULL, **tmp_ca_used;
931 	u_char type, *rdata = NULL;
932 	const u_char *blob;
933 	size_t i, j, sig_off, sects_off, rlen, blen, nca_used;
934 	u_int format_version;
935 
936 	nca_used = 0;
937 	*krlp = NULL;
938 	if (sshbuf_len(buf) < sizeof(KRL_MAGIC) - 1 ||
939 	    memcmp(sshbuf_ptr(buf), KRL_MAGIC, sizeof(KRL_MAGIC) - 1) != 0) {
940 		debug3("%s: not a KRL", __func__);
941 		return SSH_ERR_KRL_BAD_MAGIC;
942 	}
943 
944 	/* Take a copy of the KRL buffer so we can verify its signature later */
945 	if ((copy = sshbuf_fromb(buf)) == NULL) {
946 		r = SSH_ERR_ALLOC_FAIL;
947 		goto out;
948 	}
949 	if ((r = sshbuf_consume(copy, sizeof(KRL_MAGIC) - 1)) != 0)
950 		goto out;
951 
952 	if ((krl = ssh_krl_init()) == NULL) {
953 		error("%s: alloc failed", __func__);
954 		goto out;
955 	}
956 
957 	if ((r = sshbuf_get_u32(copy, &format_version)) != 0)
958 		goto out;
959 	if (format_version != KRL_FORMAT_VERSION) {
960 		r = SSH_ERR_INVALID_FORMAT;
961 		goto out;
962 	}
963 	if ((r = sshbuf_get_u64(copy, &krl->krl_version)) != 0 ||
964 	    (r = sshbuf_get_u64(copy, &krl->generated_date)) != 0 ||
965 	    (r = sshbuf_get_u64(copy, &krl->flags)) != 0 ||
966 	    (r = sshbuf_skip_string(copy)) != 0 ||
967 	    (r = sshbuf_get_cstring(copy, &krl->comment, NULL)) != 0)
968 		goto out;
969 
970 	format_timestamp(krl->generated_date, timestamp, sizeof(timestamp));
971 	debug("KRL version %llu generated at %s%s%s",
972 	    (long long unsigned)krl->krl_version, timestamp,
973 	    *krl->comment ? ": " : "", krl->comment);
974 
975 	/*
976 	 * 1st pass: verify signatures, if any. This is done to avoid
977 	 * detailed parsing of data whose provenance is unverified.
978 	 */
979 	sig_seen = 0;
980 	if (sshbuf_len(buf) < sshbuf_len(copy)) {
981 		/* Shouldn't happen */
982 		r = SSH_ERR_INTERNAL_ERROR;
983 		goto out;
984 	}
985 	sects_off = sshbuf_len(buf) - sshbuf_len(copy);
986 	while (sshbuf_len(copy) > 0) {
987 		if ((r = sshbuf_get_u8(copy, &type)) != 0 ||
988 		    (r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0)
989 			goto out;
990 		KRL_DBG(("%s: first pass, section 0x%02x", __func__, type));
991 		if (type != KRL_SECTION_SIGNATURE) {
992 			if (sig_seen) {
993 				error("KRL contains non-signature section "
994 				    "after signature");
995 				r = SSH_ERR_INVALID_FORMAT;
996 				goto out;
997 			}
998 			/* Not interested for now. */
999 			continue;
1000 		}
1001 		sig_seen = 1;
1002 		/* First string component is the signing key */
1003 		if ((r = sshkey_from_blob(blob, blen, &key)) != 0) {
1004 			r = SSH_ERR_INVALID_FORMAT;
1005 			goto out;
1006 		}
1007 		if (sshbuf_len(buf) < sshbuf_len(copy)) {
1008 			/* Shouldn't happen */
1009 			r = SSH_ERR_INTERNAL_ERROR;
1010 			goto out;
1011 		}
1012 		sig_off = sshbuf_len(buf) - sshbuf_len(copy);
1013 		/* Second string component is the signature itself */
1014 		if ((r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0) {
1015 			r = SSH_ERR_INVALID_FORMAT;
1016 			goto out;
1017 		}
1018 		/* Check signature over entire KRL up to this point */
1019 		if ((r = sshkey_verify(key, blob, blen,
1020 		    sshbuf_ptr(buf), sshbuf_len(buf) - sig_off, 0)) != 0)
1021 			goto out;
1022 		/* Check if this key has already signed this KRL */
1023 		for (i = 0; i < nca_used; i++) {
1024 			if (sshkey_equal(ca_used[i], key)) {
1025 				error("KRL signed more than once with "
1026 				    "the same key");
1027 				r = SSH_ERR_INVALID_FORMAT;
1028 				goto out;
1029 			}
1030 		}
1031 		/* Record keys used to sign the KRL */
1032 		tmp_ca_used = reallocarray(ca_used, nca_used + 1,
1033 		    sizeof(*ca_used));
1034 		if (tmp_ca_used == NULL) {
1035 			r = SSH_ERR_ALLOC_FAIL;
1036 			goto out;
1037 		}
1038 		ca_used = tmp_ca_used;
1039 		ca_used[nca_used++] = key;
1040 		key = NULL;
1041 		break;
1042 	}
1043 
1044 	if (sshbuf_len(copy) != 0) {
1045 		/* Shouldn't happen */
1046 		r = SSH_ERR_INTERNAL_ERROR;
1047 		goto out;
1048 	}
1049 
1050 	/*
1051 	 * 2nd pass: parse and load the KRL, skipping the header to the point
1052 	 * where the section start.
1053 	 */
1054 	sshbuf_free(copy);
1055 	if ((copy = sshbuf_fromb(buf)) == NULL) {
1056 		r = SSH_ERR_ALLOC_FAIL;
1057 		goto out;
1058 	}
1059 	if ((r = sshbuf_consume(copy, sects_off)) != 0)
1060 		goto out;
1061 	while (sshbuf_len(copy) > 0) {
1062 		if (sect != NULL) {
1063 			sshbuf_free(sect);
1064 			sect = NULL;
1065 		}
1066 		if ((r = sshbuf_get_u8(copy, &type)) != 0 ||
1067 		    (r = sshbuf_froms(copy, &sect)) != 0)
1068 			goto out;
1069 		KRL_DBG(("%s: second pass, section 0x%02x", __func__, type));
1070 
1071 		switch (type) {
1072 		case KRL_SECTION_CERTIFICATES:
1073 			if ((r = parse_revoked_certs(sect, krl)) != 0)
1074 				goto out;
1075 			break;
1076 		case KRL_SECTION_EXPLICIT_KEY:
1077 		case KRL_SECTION_FINGERPRINT_SHA1:
1078 			while (sshbuf_len(sect) > 0) {
1079 				if ((r = sshbuf_get_string(sect,
1080 				    &rdata, &rlen)) != 0)
1081 					goto out;
1082 				if (type == KRL_SECTION_FINGERPRINT_SHA1 &&
1083 				    rlen != 20) {
1084 					error("%s: bad SHA1 length", __func__);
1085 					r = SSH_ERR_INVALID_FORMAT;
1086 					goto out;
1087 				}
1088 				if ((r = revoke_blob(
1089 				    type == KRL_SECTION_EXPLICIT_KEY ?
1090 				    &krl->revoked_keys : &krl->revoked_sha1s,
1091 				    rdata, rlen)) != 0)
1092 					goto out;
1093 				rdata = NULL; /* revoke_blob frees rdata */
1094 			}
1095 			break;
1096 		case KRL_SECTION_SIGNATURE:
1097 			/* Handled above, but still need to stay in synch */
1098 			sshbuf_reset(sect);
1099 			sect = NULL;
1100 			if ((r = sshbuf_skip_string(copy)) != 0)
1101 				goto out;
1102 			break;
1103 		default:
1104 			error("Unsupported KRL section %u", type);
1105 			r = SSH_ERR_INVALID_FORMAT;
1106 			goto out;
1107 		}
1108 		if (sshbuf_len(sect) > 0) {
1109 			error("KRL section contains unparsed data");
1110 			r = SSH_ERR_INVALID_FORMAT;
1111 			goto out;
1112 		}
1113 	}
1114 
1115 	/* Check that the key(s) used to sign the KRL weren't revoked */
1116 	sig_seen = 0;
1117 	for (i = 0; i < nca_used; i++) {
1118 		if (ssh_krl_check_key(krl, ca_used[i]) == 0)
1119 			sig_seen = 1;
1120 		else {
1121 			sshkey_free(ca_used[i]);
1122 			ca_used[i] = NULL;
1123 		}
1124 	}
1125 	if (nca_used && !sig_seen) {
1126 		error("All keys used to sign KRL were revoked");
1127 		r = SSH_ERR_KEY_REVOKED;
1128 		goto out;
1129 	}
1130 
1131 	/* If we have CA keys, then verify that one was used to sign the KRL */
1132 	if (sig_seen && nsign_ca_keys != 0) {
1133 		sig_seen = 0;
1134 		for (i = 0; !sig_seen && i < nsign_ca_keys; i++) {
1135 			for (j = 0; j < nca_used; j++) {
1136 				if (ca_used[j] == NULL)
1137 					continue;
1138 				if (sshkey_equal(ca_used[j], sign_ca_keys[i])) {
1139 					sig_seen = 1;
1140 					break;
1141 				}
1142 			}
1143 		}
1144 		if (!sig_seen) {
1145 			r = SSH_ERR_SIGNATURE_INVALID;
1146 			error("KRL not signed with any trusted key");
1147 			goto out;
1148 		}
1149 	}
1150 
1151 	*krlp = krl;
1152 	r = 0;
1153  out:
1154 	if (r != 0)
1155 		ssh_krl_free(krl);
1156 	for (i = 0; i < nca_used; i++)
1157 		sshkey_free(ca_used[i]);
1158 	free(ca_used);
1159 	free(rdata);
1160 	sshkey_free(key);
1161 	sshbuf_free(copy);
1162 	sshbuf_free(sect);
1163 	return r;
1164 }
1165 
1166 /* Checks certificate serial number and key ID revocation */
1167 static int
1168 is_cert_revoked(const struct sshkey *key, struct revoked_certs *rc)
1169 {
1170 	struct revoked_serial rs, *ers;
1171 	struct revoked_key_id rki, *erki;
1172 
1173 	/* Check revocation by cert key ID */
1174 	memset(&rki, 0, sizeof(rki));
1175 	rki.key_id = key->cert->key_id;
1176 	erki = RB_FIND(revoked_key_id_tree, &rc->revoked_key_ids, &rki);
1177 	if (erki != NULL) {
1178 		KRL_DBG(("%s: revoked by key ID", __func__));
1179 		return SSH_ERR_KEY_REVOKED;
1180 	}
1181 
1182 	/*
1183 	 * Zero serials numbers are ignored (it's the default when the
1184 	 * CA doesn't specify one).
1185 	 */
1186 	if (key->cert->serial == 0)
1187 		return 0;
1188 
1189 	memset(&rs, 0, sizeof(rs));
1190 	rs.lo = rs.hi = key->cert->serial;
1191 	ers = RB_FIND(revoked_serial_tree, &rc->revoked_serials, &rs);
1192 	if (ers != NULL) {
1193 		KRL_DBG(("%s: revoked serial %llu matched %llu:%llu", __func__,
1194 		    key->cert->serial, ers->lo, ers->hi));
1195 		return SSH_ERR_KEY_REVOKED;
1196 	}
1197 	return 0;
1198 }
1199 
1200 /* Checks whether a given key/cert is revoked. Does not check its CA */
1201 static int
1202 is_key_revoked(struct ssh_krl *krl, const struct sshkey *key)
1203 {
1204 	struct revoked_blob rb, *erb;
1205 	struct revoked_certs *rc;
1206 	int r;
1207 
1208 	/* Check explicitly revoked hashes first */
1209 	memset(&rb, 0, sizeof(rb));
1210 	if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA1,
1211 	    &rb.blob, &rb.len)) != 0)
1212 		return r;
1213 	erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha1s, &rb);
1214 	free(rb.blob);
1215 	if (erb != NULL) {
1216 		KRL_DBG(("%s: revoked by key SHA1", __func__));
1217 		return SSH_ERR_KEY_REVOKED;
1218 	}
1219 
1220 	/* Next, explicit keys */
1221 	memset(&rb, 0, sizeof(rb));
1222 	if ((r = plain_key_blob(key, &rb.blob, &rb.len)) != 0)
1223 		return r;
1224 	erb = RB_FIND(revoked_blob_tree, &krl->revoked_keys, &rb);
1225 	free(rb.blob);
1226 	if (erb != NULL) {
1227 		KRL_DBG(("%s: revoked by explicit key", __func__));
1228 		return SSH_ERR_KEY_REVOKED;
1229 	}
1230 
1231 	if (!sshkey_is_cert(key))
1232 		return 0;
1233 
1234 	/* Check cert revocation for the specified CA */
1235 	if ((r = revoked_certs_for_ca_key(krl, key->cert->signature_key,
1236 	    &rc, 0)) != 0)
1237 		return r;
1238 	if (rc != NULL) {
1239 		if ((r = is_cert_revoked(key, rc)) != 0)
1240 			return r;
1241 	}
1242 	/* Check cert revocation for the wildcard CA */
1243 	if ((r = revoked_certs_for_ca_key(krl, NULL, &rc, 0)) != 0)
1244 		return r;
1245 	if (rc != NULL) {
1246 		if ((r = is_cert_revoked(key, rc)) != 0)
1247 			return r;
1248 	}
1249 
1250 	KRL_DBG(("%s: %llu no match", __func__, key->cert->serial));
1251 	return 0;
1252 }
1253 
1254 int
1255 ssh_krl_check_key(struct ssh_krl *krl, const struct sshkey *key)
1256 {
1257 	int r;
1258 
1259 	KRL_DBG(("%s: checking key", __func__));
1260 	if ((r = is_key_revoked(krl, key)) != 0)
1261 		return r;
1262 	if (sshkey_is_cert(key)) {
1263 		debug2("%s: checking CA key", __func__);
1264 		if ((r = is_key_revoked(krl, key->cert->signature_key)) != 0)
1265 			return r;
1266 	}
1267 	KRL_DBG(("%s: key okay", __func__));
1268 	return 0;
1269 }
1270 
1271 int
1272 ssh_krl_file_contains_key(const char *path, const struct sshkey *key)
1273 {
1274 	struct sshbuf *krlbuf = NULL;
1275 	struct ssh_krl *krl = NULL;
1276 	int oerrno = 0, r, fd;
1277 
1278 	if (path == NULL)
1279 		return 0;
1280 
1281 	if ((krlbuf = sshbuf_new()) == NULL)
1282 		return SSH_ERR_ALLOC_FAIL;
1283 	if ((fd = open(path, O_RDONLY)) == -1) {
1284 		r = SSH_ERR_SYSTEM_ERROR;
1285 		oerrno = errno;
1286 		goto out;
1287 	}
1288 	if ((r = sshkey_load_file(fd, krlbuf)) != 0) {
1289 		oerrno = errno;
1290 		goto out;
1291 	}
1292 	if ((r = ssh_krl_from_blob(krlbuf, &krl, NULL, 0)) != 0)
1293 		goto out;
1294 	debug2("%s: checking KRL %s", __func__, path);
1295 	r = ssh_krl_check_key(krl, key);
1296  out:
1297 	close(fd);
1298 	sshbuf_free(krlbuf);
1299 	ssh_krl_free(krl);
1300 	if (r != 0)
1301 		errno = oerrno;
1302 	return r;
1303 }
1304