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 1.31 2015/01/30 01:10:33 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
serial_cmp(struct revoked_serial * a,struct revoked_serial * b)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
key_id_cmp(struct revoked_key_id * a,struct revoked_key_id * b)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
blob_cmp(struct revoked_blob * a,struct revoked_blob * b)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 *
ssh_krl_init(void)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
revoked_certs_free(struct revoked_certs * rc)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
ssh_krl_free(struct ssh_krl * krl)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
ssh_krl_set_version(struct ssh_krl * krl,u_int64_t version)189 ssh_krl_set_version(struct ssh_krl *krl, u_int64_t version)
190 {
191 krl->krl_version = version;
192 }
193
194 int
ssh_krl_set_comment(struct ssh_krl * krl,const char * comment)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
revoked_certs_for_ca_key(struct ssh_krl * krl,const struct sshkey * ca_key,struct revoked_certs ** rcp,int allow_create)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
insert_serial_range(struct revoked_serial_tree * rt,u_int64_t lo,u_int64_t hi)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
ssh_krl_revoke_cert_by_serial(struct ssh_krl * krl,const struct sshkey * ca_key,u_int64_t serial)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
ssh_krl_revoke_cert_by_serial_range(struct ssh_krl * krl,const struct sshkey * ca_key,u_int64_t lo,u_int64_t hi)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
ssh_krl_revoke_cert_by_key_id(struct ssh_krl * krl,const struct sshkey * ca_key,const char * key_id)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
plain_key_blob(const struct sshkey * key,u_char ** blob,size_t * blen)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
revoke_blob(struct revoked_blob_tree * rbt,u_char * blob,size_t len)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
ssh_krl_revoke_key_explicit(struct ssh_krl * krl,const struct sshkey * key)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
ssh_krl_revoke_key_sha1(struct ssh_krl * krl,const struct sshkey * key)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
ssh_krl_revoke_key(struct ssh_krl * krl,const struct sshkey * key)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 (sshkey_cert_is_legacy(key) || 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
choose_next_state(int current_state,u_int64_t contig,int final,u_int64_t last_gap,u_int64_t next_gap,int * force_new_section)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
put_bitmap(struct sshbuf * buf,struct bitmap * bitmap)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
revoked_certs_generate(struct revoked_certs * rc,struct sshbuf * buf)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
ssh_krl_to_blob(struct ssh_krl * krl,struct sshbuf * buf,const struct sshkey ** sign_keys,u_int nsign_keys)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)) == -1)
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
format_timestamp(u_int64_t timestamp,char * ts,size_t nts)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
parse_revoked_certs(struct sshbuf * buf,struct ssh_krl * krl)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
ssh_krl_from_blob(struct sshbuf * buf,struct ssh_krl ** krlp,const struct sshkey ** sign_ca_keys,size_t nsign_ca_keys)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, §)) != 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
is_cert_revoked(const struct sshkey * key,struct revoked_certs * rc)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 * Legacy cert formats lack serial numbers. Zero serials numbers
1184 * are ignored (it's the default when the CA doesn't specify one).
1185 */
1186 if (sshkey_cert_is_legacy(key) || 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
is_key_revoked(struct ssh_krl * krl,const struct sshkey * key)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
ssh_krl_check_key(struct ssh_krl * krl,const struct sshkey * key)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
ssh_krl_file_contains_key(const char * path,const struct sshkey * key)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