xref: /freebsd/crypto/openssh/krl.c (revision 7447ca0eb235974642312b9555caec00b57d8fc1)
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 1.37 2015/12/31 00:33:52 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), NULL, 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 		sshbuf_free(subsect);
830 		subsect = NULL;
831 		if ((r = sshbuf_get_u8(buf, &type)) != 0 ||
832 		    (r = sshbuf_froms(buf, &subsect)) != 0)
833 			goto out;
834 		KRL_DBG(("%s: subsection type 0x%02x", __func__, type));
835 		/* sshbuf_dump(subsect, stderr); */
836 
837 		switch (type) {
838 		case KRL_SECTION_CERT_SERIAL_LIST:
839 			while (sshbuf_len(subsect) > 0) {
840 				if ((r = sshbuf_get_u64(subsect, &serial)) != 0)
841 					goto out;
842 				if ((r = ssh_krl_revoke_cert_by_serial(krl,
843 				    ca_key, serial)) != 0)
844 					goto out;
845 			}
846 			break;
847 		case KRL_SECTION_CERT_SERIAL_RANGE:
848 			if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 ||
849 			    (r = sshbuf_get_u64(subsect, &serial_hi)) != 0)
850 				goto out;
851 			if ((r = ssh_krl_revoke_cert_by_serial_range(krl,
852 			    ca_key, serial_lo, serial_hi)) != 0)
853 				goto out;
854 			break;
855 		case KRL_SECTION_CERT_SERIAL_BITMAP:
856 			if ((bitmap = bitmap_new()) == NULL) {
857 				r = SSH_ERR_ALLOC_FAIL;
858 				goto out;
859 			}
860 			if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 ||
861 			    (r = sshbuf_get_bignum2_bytes_direct(subsect,
862 			    &blob, &blen)) != 0)
863 				goto out;
864 			if (bitmap_from_string(bitmap, blob, blen) != 0) {
865 				r = SSH_ERR_INVALID_FORMAT;
866 				goto out;
867 			}
868 			nbits = bitmap_nbits(bitmap);
869 			for (serial = 0; serial < (u_int64_t)nbits; serial++) {
870 				if (serial > 0 && serial_lo + serial == 0) {
871 					error("%s: bitmap wraps u64", __func__);
872 					r = SSH_ERR_INVALID_FORMAT;
873 					goto out;
874 				}
875 				if (!bitmap_test_bit(bitmap, serial))
876 					continue;
877 				if ((r = ssh_krl_revoke_cert_by_serial(krl,
878 				    ca_key, serial_lo + serial)) != 0)
879 					goto out;
880 			}
881 			bitmap_free(bitmap);
882 			bitmap = NULL;
883 			break;
884 		case KRL_SECTION_CERT_KEY_ID:
885 			while (sshbuf_len(subsect) > 0) {
886 				if ((r = sshbuf_get_cstring(subsect,
887 				    &key_id, NULL)) != 0)
888 					goto out;
889 				if ((r = ssh_krl_revoke_cert_by_key_id(krl,
890 				    ca_key, key_id)) != 0)
891 					goto out;
892 				free(key_id);
893 				key_id = NULL;
894 			}
895 			break;
896 		default:
897 			error("Unsupported KRL certificate section %u", type);
898 			r = SSH_ERR_INVALID_FORMAT;
899 			goto out;
900 		}
901 		if (sshbuf_len(subsect) > 0) {
902 			error("KRL certificate section contains unparsed data");
903 			r = SSH_ERR_INVALID_FORMAT;
904 			goto out;
905 		}
906 	}
907 
908 	r = 0;
909  out:
910 	if (bitmap != NULL)
911 		bitmap_free(bitmap);
912 	free(key_id);
913 	sshkey_free(ca_key);
914 	sshbuf_free(subsect);
915 	return r;
916 }
917 
918 
919 /* Attempt to parse a KRL, checking its signature (if any) with sign_ca_keys. */
920 int
921 ssh_krl_from_blob(struct sshbuf *buf, struct ssh_krl **krlp,
922     const struct sshkey **sign_ca_keys, size_t nsign_ca_keys)
923 {
924 	struct sshbuf *copy = NULL, *sect = NULL;
925 	struct ssh_krl *krl = NULL;
926 	char timestamp[64];
927 	int r = SSH_ERR_INTERNAL_ERROR, sig_seen;
928 	struct sshkey *key = NULL, **ca_used = NULL, **tmp_ca_used;
929 	u_char type, *rdata = NULL;
930 	const u_char *blob;
931 	size_t i, j, sig_off, sects_off, rlen, blen, nca_used;
932 	u_int format_version;
933 
934 	nca_used = 0;
935 	*krlp = NULL;
936 	if (sshbuf_len(buf) < sizeof(KRL_MAGIC) - 1 ||
937 	    memcmp(sshbuf_ptr(buf), KRL_MAGIC, sizeof(KRL_MAGIC) - 1) != 0) {
938 		debug3("%s: not a KRL", __func__);
939 		return SSH_ERR_KRL_BAD_MAGIC;
940 	}
941 
942 	/* Take a copy of the KRL buffer so we can verify its signature later */
943 	if ((copy = sshbuf_fromb(buf)) == NULL) {
944 		r = SSH_ERR_ALLOC_FAIL;
945 		goto out;
946 	}
947 	if ((r = sshbuf_consume(copy, sizeof(KRL_MAGIC) - 1)) != 0)
948 		goto out;
949 
950 	if ((krl = ssh_krl_init()) == NULL) {
951 		error("%s: alloc failed", __func__);
952 		goto out;
953 	}
954 
955 	if ((r = sshbuf_get_u32(copy, &format_version)) != 0)
956 		goto out;
957 	if (format_version != KRL_FORMAT_VERSION) {
958 		r = SSH_ERR_INVALID_FORMAT;
959 		goto out;
960 	}
961 	if ((r = sshbuf_get_u64(copy, &krl->krl_version)) != 0 ||
962 	    (r = sshbuf_get_u64(copy, &krl->generated_date)) != 0 ||
963 	    (r = sshbuf_get_u64(copy, &krl->flags)) != 0 ||
964 	    (r = sshbuf_skip_string(copy)) != 0 ||
965 	    (r = sshbuf_get_cstring(copy, &krl->comment, NULL)) != 0)
966 		goto out;
967 
968 	format_timestamp(krl->generated_date, timestamp, sizeof(timestamp));
969 	debug("KRL version %llu generated at %s%s%s",
970 	    (long long unsigned)krl->krl_version, timestamp,
971 	    *krl->comment ? ": " : "", krl->comment);
972 
973 	/*
974 	 * 1st pass: verify signatures, if any. This is done to avoid
975 	 * detailed parsing of data whose provenance is unverified.
976 	 */
977 	sig_seen = 0;
978 	if (sshbuf_len(buf) < sshbuf_len(copy)) {
979 		/* Shouldn't happen */
980 		r = SSH_ERR_INTERNAL_ERROR;
981 		goto out;
982 	}
983 	sects_off = sshbuf_len(buf) - sshbuf_len(copy);
984 	while (sshbuf_len(copy) > 0) {
985 		if ((r = sshbuf_get_u8(copy, &type)) != 0 ||
986 		    (r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0)
987 			goto out;
988 		KRL_DBG(("%s: first pass, section 0x%02x", __func__, type));
989 		if (type != KRL_SECTION_SIGNATURE) {
990 			if (sig_seen) {
991 				error("KRL contains non-signature section "
992 				    "after signature");
993 				r = SSH_ERR_INVALID_FORMAT;
994 				goto out;
995 			}
996 			/* Not interested for now. */
997 			continue;
998 		}
999 		sig_seen = 1;
1000 		/* First string component is the signing key */
1001 		if ((r = sshkey_from_blob(blob, blen, &key)) != 0) {
1002 			r = SSH_ERR_INVALID_FORMAT;
1003 			goto out;
1004 		}
1005 		if (sshbuf_len(buf) < sshbuf_len(copy)) {
1006 			/* Shouldn't happen */
1007 			r = SSH_ERR_INTERNAL_ERROR;
1008 			goto out;
1009 		}
1010 		sig_off = sshbuf_len(buf) - sshbuf_len(copy);
1011 		/* Second string component is the signature itself */
1012 		if ((r = sshbuf_get_string_direct(copy, &blob, &blen)) != 0) {
1013 			r = SSH_ERR_INVALID_FORMAT;
1014 			goto out;
1015 		}
1016 		/* Check signature over entire KRL up to this point */
1017 		if ((r = sshkey_verify(key, blob, blen,
1018 		    sshbuf_ptr(buf), sig_off, 0)) != 0)
1019 			goto out;
1020 		/* Check if this key has already signed this KRL */
1021 		for (i = 0; i < nca_used; i++) {
1022 			if (sshkey_equal(ca_used[i], key)) {
1023 				error("KRL signed more than once with "
1024 				    "the same key");
1025 				r = SSH_ERR_INVALID_FORMAT;
1026 				goto out;
1027 			}
1028 		}
1029 		/* Record keys used to sign the KRL */
1030 		tmp_ca_used = reallocarray(ca_used, nca_used + 1,
1031 		    sizeof(*ca_used));
1032 		if (tmp_ca_used == NULL) {
1033 			r = SSH_ERR_ALLOC_FAIL;
1034 			goto out;
1035 		}
1036 		ca_used = tmp_ca_used;
1037 		ca_used[nca_used++] = key;
1038 		key = NULL;
1039 	}
1040 
1041 	if (sshbuf_len(copy) != 0) {
1042 		/* Shouldn't happen */
1043 		r = SSH_ERR_INTERNAL_ERROR;
1044 		goto out;
1045 	}
1046 
1047 	/*
1048 	 * 2nd pass: parse and load the KRL, skipping the header to the point
1049 	 * where the section start.
1050 	 */
1051 	sshbuf_free(copy);
1052 	if ((copy = sshbuf_fromb(buf)) == NULL) {
1053 		r = SSH_ERR_ALLOC_FAIL;
1054 		goto out;
1055 	}
1056 	if ((r = sshbuf_consume(copy, sects_off)) != 0)
1057 		goto out;
1058 	while (sshbuf_len(copy) > 0) {
1059 		sshbuf_free(sect);
1060 		sect = NULL;
1061 		if ((r = sshbuf_get_u8(copy, &type)) != 0 ||
1062 		    (r = sshbuf_froms(copy, &sect)) != 0)
1063 			goto out;
1064 		KRL_DBG(("%s: second pass, section 0x%02x", __func__, type));
1065 
1066 		switch (type) {
1067 		case KRL_SECTION_CERTIFICATES:
1068 			if ((r = parse_revoked_certs(sect, krl)) != 0)
1069 				goto out;
1070 			break;
1071 		case KRL_SECTION_EXPLICIT_KEY:
1072 		case KRL_SECTION_FINGERPRINT_SHA1:
1073 			while (sshbuf_len(sect) > 0) {
1074 				if ((r = sshbuf_get_string(sect,
1075 				    &rdata, &rlen)) != 0)
1076 					goto out;
1077 				if (type == KRL_SECTION_FINGERPRINT_SHA1 &&
1078 				    rlen != 20) {
1079 					error("%s: bad SHA1 length", __func__);
1080 					r = SSH_ERR_INVALID_FORMAT;
1081 					goto out;
1082 				}
1083 				if ((r = revoke_blob(
1084 				    type == KRL_SECTION_EXPLICIT_KEY ?
1085 				    &krl->revoked_keys : &krl->revoked_sha1s,
1086 				    rdata, rlen)) != 0)
1087 					goto out;
1088 				rdata = NULL; /* revoke_blob frees rdata */
1089 			}
1090 			break;
1091 		case KRL_SECTION_SIGNATURE:
1092 			/* Handled above, but still need to stay in synch */
1093 			sshbuf_reset(sect);
1094 			sect = NULL;
1095 			if ((r = sshbuf_skip_string(copy)) != 0)
1096 				goto out;
1097 			break;
1098 		default:
1099 			error("Unsupported KRL section %u", type);
1100 			r = SSH_ERR_INVALID_FORMAT;
1101 			goto out;
1102 		}
1103 		if (sect != NULL && sshbuf_len(sect) > 0) {
1104 			error("KRL section contains unparsed data");
1105 			r = SSH_ERR_INVALID_FORMAT;
1106 			goto out;
1107 		}
1108 	}
1109 
1110 	/* Check that the key(s) used to sign the KRL weren't revoked */
1111 	sig_seen = 0;
1112 	for (i = 0; i < nca_used; i++) {
1113 		if (ssh_krl_check_key(krl, ca_used[i]) == 0)
1114 			sig_seen = 1;
1115 		else {
1116 			sshkey_free(ca_used[i]);
1117 			ca_used[i] = NULL;
1118 		}
1119 	}
1120 	if (nca_used && !sig_seen) {
1121 		error("All keys used to sign KRL were revoked");
1122 		r = SSH_ERR_KEY_REVOKED;
1123 		goto out;
1124 	}
1125 
1126 	/* If we have CA keys, then verify that one was used to sign the KRL */
1127 	if (sig_seen && nsign_ca_keys != 0) {
1128 		sig_seen = 0;
1129 		for (i = 0; !sig_seen && i < nsign_ca_keys; i++) {
1130 			for (j = 0; j < nca_used; j++) {
1131 				if (ca_used[j] == NULL)
1132 					continue;
1133 				if (sshkey_equal(ca_used[j], sign_ca_keys[i])) {
1134 					sig_seen = 1;
1135 					break;
1136 				}
1137 			}
1138 		}
1139 		if (!sig_seen) {
1140 			r = SSH_ERR_SIGNATURE_INVALID;
1141 			error("KRL not signed with any trusted key");
1142 			goto out;
1143 		}
1144 	}
1145 
1146 	*krlp = krl;
1147 	r = 0;
1148  out:
1149 	if (r != 0)
1150 		ssh_krl_free(krl);
1151 	for (i = 0; i < nca_used; i++)
1152 		sshkey_free(ca_used[i]);
1153 	free(ca_used);
1154 	free(rdata);
1155 	sshkey_free(key);
1156 	sshbuf_free(copy);
1157 	sshbuf_free(sect);
1158 	return r;
1159 }
1160 
1161 /* Checks certificate serial number and key ID revocation */
1162 static int
1163 is_cert_revoked(const struct sshkey *key, struct revoked_certs *rc)
1164 {
1165 	struct revoked_serial rs, *ers;
1166 	struct revoked_key_id rki, *erki;
1167 
1168 	/* Check revocation by cert key ID */
1169 	memset(&rki, 0, sizeof(rki));
1170 	rki.key_id = key->cert->key_id;
1171 	erki = RB_FIND(revoked_key_id_tree, &rc->revoked_key_ids, &rki);
1172 	if (erki != NULL) {
1173 		KRL_DBG(("%s: revoked by key ID", __func__));
1174 		return SSH_ERR_KEY_REVOKED;
1175 	}
1176 
1177 	/*
1178 	 * Zero serials numbers are ignored (it's the default when the
1179 	 * CA doesn't specify one).
1180 	 */
1181 	if (key->cert->serial == 0)
1182 		return 0;
1183 
1184 	memset(&rs, 0, sizeof(rs));
1185 	rs.lo = rs.hi = key->cert->serial;
1186 	ers = RB_FIND(revoked_serial_tree, &rc->revoked_serials, &rs);
1187 	if (ers != NULL) {
1188 		KRL_DBG(("%s: revoked serial %llu matched %llu:%llu", __func__,
1189 		    key->cert->serial, ers->lo, ers->hi));
1190 		return SSH_ERR_KEY_REVOKED;
1191 	}
1192 	return 0;
1193 }
1194 
1195 /* Checks whether a given key/cert is revoked. Does not check its CA */
1196 static int
1197 is_key_revoked(struct ssh_krl *krl, const struct sshkey *key)
1198 {
1199 	struct revoked_blob rb, *erb;
1200 	struct revoked_certs *rc;
1201 	int r;
1202 
1203 	/* Check explicitly revoked hashes first */
1204 	memset(&rb, 0, sizeof(rb));
1205 	if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA1,
1206 	    &rb.blob, &rb.len)) != 0)
1207 		return r;
1208 	erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha1s, &rb);
1209 	free(rb.blob);
1210 	if (erb != NULL) {
1211 		KRL_DBG(("%s: revoked by key SHA1", __func__));
1212 		return SSH_ERR_KEY_REVOKED;
1213 	}
1214 
1215 	/* Next, explicit keys */
1216 	memset(&rb, 0, sizeof(rb));
1217 	if ((r = plain_key_blob(key, &rb.blob, &rb.len)) != 0)
1218 		return r;
1219 	erb = RB_FIND(revoked_blob_tree, &krl->revoked_keys, &rb);
1220 	free(rb.blob);
1221 	if (erb != NULL) {
1222 		KRL_DBG(("%s: revoked by explicit key", __func__));
1223 		return SSH_ERR_KEY_REVOKED;
1224 	}
1225 
1226 	if (!sshkey_is_cert(key))
1227 		return 0;
1228 
1229 	/* Check cert revocation for the specified CA */
1230 	if ((r = revoked_certs_for_ca_key(krl, key->cert->signature_key,
1231 	    &rc, 0)) != 0)
1232 		return r;
1233 	if (rc != NULL) {
1234 		if ((r = is_cert_revoked(key, rc)) != 0)
1235 			return r;
1236 	}
1237 	/* Check cert revocation for the wildcard CA */
1238 	if ((r = revoked_certs_for_ca_key(krl, NULL, &rc, 0)) != 0)
1239 		return r;
1240 	if (rc != NULL) {
1241 		if ((r = is_cert_revoked(key, rc)) != 0)
1242 			return r;
1243 	}
1244 
1245 	KRL_DBG(("%s: %llu no match", __func__, key->cert->serial));
1246 	return 0;
1247 }
1248 
1249 int
1250 ssh_krl_check_key(struct ssh_krl *krl, const struct sshkey *key)
1251 {
1252 	int r;
1253 
1254 	KRL_DBG(("%s: checking key", __func__));
1255 	if ((r = is_key_revoked(krl, key)) != 0)
1256 		return r;
1257 	if (sshkey_is_cert(key)) {
1258 		debug2("%s: checking CA key", __func__);
1259 		if ((r = is_key_revoked(krl, key->cert->signature_key)) != 0)
1260 			return r;
1261 	}
1262 	KRL_DBG(("%s: key okay", __func__));
1263 	return 0;
1264 }
1265 
1266 int
1267 ssh_krl_file_contains_key(const char *path, const struct sshkey *key)
1268 {
1269 	struct sshbuf *krlbuf = NULL;
1270 	struct ssh_krl *krl = NULL;
1271 	int oerrno = 0, r, fd;
1272 
1273 	if (path == NULL)
1274 		return 0;
1275 
1276 	if ((krlbuf = sshbuf_new()) == NULL)
1277 		return SSH_ERR_ALLOC_FAIL;
1278 	if ((fd = open(path, O_RDONLY)) == -1) {
1279 		r = SSH_ERR_SYSTEM_ERROR;
1280 		oerrno = errno;
1281 		goto out;
1282 	}
1283 	if ((r = sshkey_load_file(fd, krlbuf)) != 0) {
1284 		oerrno = errno;
1285 		goto out;
1286 	}
1287 	if ((r = ssh_krl_from_blob(krlbuf, &krl, NULL, 0)) != 0)
1288 		goto out;
1289 	debug2("%s: checking KRL %s", __func__, path);
1290 	r = ssh_krl_check_key(krl, key);
1291  out:
1292 	close(fd);
1293 	sshbuf_free(krlbuf);
1294 	ssh_krl_free(krl);
1295 	if (r != 0)
1296 		errno = oerrno;
1297 	return r;
1298 }
1299