1 /* $OpenBSD: krl.c,v 1.59 2023/07/17 05:22:30 djm Exp $ */
2 /*
3 * Copyright (c) 2012 Damien Miller <djm@mindrot.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 #include "includes.h"
19
20 #include <sys/types.h>
21 #include <openbsd-compat/sys-tree.h>
22 #include <openbsd-compat/sys-queue.h>
23
24 #include <errno.h>
25 #include <fcntl.h>
26 #include <limits.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <time.h>
30 #include <unistd.h>
31
32 #include "sshbuf.h"
33 #include "ssherr.h"
34 #include "sshkey.h"
35 #include "authfile.h"
36 #include "misc.h"
37 #include "log.h"
38 #include "digest.h"
39 #include "bitmap.h"
40 #include "utf8.h"
41
42 #include "krl.h"
43
44 /* #define DEBUG_KRL */
45 #ifdef DEBUG_KRL
46 # define KRL_DBG(x) debug3_f 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_blob_tree revoked_sha256s;
101 struct revoked_certs_list revoked_certs;
102 };
103
104 /* Return equal if a and b overlap */
105 static int
serial_cmp(struct revoked_serial * a,struct revoked_serial * b)106 serial_cmp(struct revoked_serial *a, struct revoked_serial *b)
107 {
108 if (a->hi >= b->lo && a->lo <= b->hi)
109 return 0;
110 return a->lo < b->lo ? -1 : 1;
111 }
112
113 static int
key_id_cmp(struct revoked_key_id * a,struct revoked_key_id * b)114 key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b)
115 {
116 return strcmp(a->key_id, b->key_id);
117 }
118
119 static int
blob_cmp(struct revoked_blob * a,struct revoked_blob * b)120 blob_cmp(struct revoked_blob *a, struct revoked_blob *b)
121 {
122 int r;
123
124 if (a->len != b->len) {
125 if ((r = memcmp(a->blob, b->blob, MINIMUM(a->len, b->len))) != 0)
126 return r;
127 return a->len > b->len ? 1 : -1;
128 } else
129 return memcmp(a->blob, b->blob, a->len);
130 }
131
132 struct ssh_krl *
ssh_krl_init(void)133 ssh_krl_init(void)
134 {
135 struct ssh_krl *krl;
136
137 if ((krl = calloc(1, sizeof(*krl))) == NULL)
138 return NULL;
139 RB_INIT(&krl->revoked_keys);
140 RB_INIT(&krl->revoked_sha1s);
141 RB_INIT(&krl->revoked_sha256s);
142 TAILQ_INIT(&krl->revoked_certs);
143 return krl;
144 }
145
146 static void
revoked_certs_free(struct revoked_certs * rc)147 revoked_certs_free(struct revoked_certs *rc)
148 {
149 struct revoked_serial *rs, *trs;
150 struct revoked_key_id *rki, *trki;
151
152 RB_FOREACH_SAFE(rs, revoked_serial_tree, &rc->revoked_serials, trs) {
153 RB_REMOVE(revoked_serial_tree, &rc->revoked_serials, rs);
154 free(rs);
155 }
156 RB_FOREACH_SAFE(rki, revoked_key_id_tree, &rc->revoked_key_ids, trki) {
157 RB_REMOVE(revoked_key_id_tree, &rc->revoked_key_ids, rki);
158 free(rki->key_id);
159 free(rki);
160 }
161 sshkey_free(rc->ca_key);
162 }
163
164 void
ssh_krl_free(struct ssh_krl * krl)165 ssh_krl_free(struct ssh_krl *krl)
166 {
167 struct revoked_blob *rb, *trb;
168 struct revoked_certs *rc, *trc;
169
170 if (krl == NULL)
171 return;
172
173 free(krl->comment);
174 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_keys, trb) {
175 RB_REMOVE(revoked_blob_tree, &krl->revoked_keys, rb);
176 free(rb->blob);
177 free(rb);
178 }
179 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha1s, trb) {
180 RB_REMOVE(revoked_blob_tree, &krl->revoked_sha1s, rb);
181 free(rb->blob);
182 free(rb);
183 }
184 RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha256s, trb) {
185 RB_REMOVE(revoked_blob_tree, &krl->revoked_sha256s, rb);
186 free(rb->blob);
187 free(rb);
188 }
189 TAILQ_FOREACH_SAFE(rc, &krl->revoked_certs, entry, trc) {
190 TAILQ_REMOVE(&krl->revoked_certs, rc, entry);
191 revoked_certs_free(rc);
192 }
193 free(krl);
194 }
195
196 void
ssh_krl_set_version(struct ssh_krl * krl,u_int64_t version)197 ssh_krl_set_version(struct ssh_krl *krl, u_int64_t version)
198 {
199 krl->krl_version = version;
200 }
201
202 int
ssh_krl_set_comment(struct ssh_krl * krl,const char * comment)203 ssh_krl_set_comment(struct ssh_krl *krl, const char *comment)
204 {
205 free(krl->comment);
206 if ((krl->comment = strdup(comment)) == NULL)
207 return SSH_ERR_ALLOC_FAIL;
208 return 0;
209 }
210
211 /*
212 * Find the revoked_certs struct for a CA key. If allow_create is set then
213 * create a new one in the tree if one did not exist already.
214 */
215 static int
revoked_certs_for_ca_key(struct ssh_krl * krl,const struct sshkey * ca_key,struct revoked_certs ** rcp,int allow_create)216 revoked_certs_for_ca_key(struct ssh_krl *krl, const struct sshkey *ca_key,
217 struct revoked_certs **rcp, int allow_create)
218 {
219 struct revoked_certs *rc;
220 int r;
221
222 *rcp = NULL;
223 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) {
224 if ((ca_key == NULL && rc->ca_key == NULL) ||
225 sshkey_equal(rc->ca_key, ca_key)) {
226 *rcp = rc;
227 return 0;
228 }
229 }
230 if (!allow_create)
231 return 0;
232 /* If this CA doesn't exist in the list then add it now */
233 if ((rc = calloc(1, sizeof(*rc))) == NULL)
234 return SSH_ERR_ALLOC_FAIL;
235 if (ca_key == NULL)
236 rc->ca_key = NULL;
237 else if ((r = sshkey_from_private(ca_key, &rc->ca_key)) != 0) {
238 free(rc);
239 return r;
240 }
241 RB_INIT(&rc->revoked_serials);
242 RB_INIT(&rc->revoked_key_ids);
243 TAILQ_INSERT_TAIL(&krl->revoked_certs, rc, entry);
244 KRL_DBG(("new CA %s", ca_key == NULL ? "*" : sshkey_type(ca_key)));
245 *rcp = rc;
246 return 0;
247 }
248
249 static int
insert_serial_range(struct revoked_serial_tree * rt,u_int64_t lo,u_int64_t hi)250 insert_serial_range(struct revoked_serial_tree *rt, u_int64_t lo, u_int64_t hi)
251 {
252 struct revoked_serial rs, *ers, *crs, *irs;
253
254 KRL_DBG(("insert %llu:%llu", lo, hi));
255 memset(&rs, 0, sizeof(rs));
256 rs.lo = lo;
257 rs.hi = hi;
258 ers = RB_NFIND(revoked_serial_tree, rt, &rs);
259 if (ers == NULL || serial_cmp(ers, &rs) != 0) {
260 /* No entry matches. Just insert */
261 if ((irs = malloc(sizeof(rs))) == NULL)
262 return SSH_ERR_ALLOC_FAIL;
263 memcpy(irs, &rs, sizeof(*irs));
264 ers = RB_INSERT(revoked_serial_tree, rt, irs);
265 if (ers != NULL) {
266 KRL_DBG(("bad: ers != NULL"));
267 /* Shouldn't happen */
268 free(irs);
269 return SSH_ERR_INTERNAL_ERROR;
270 }
271 ers = irs;
272 } else {
273 KRL_DBG(("overlap found %llu:%llu", ers->lo, ers->hi));
274 /*
275 * The inserted entry overlaps an existing one. Grow the
276 * existing entry.
277 */
278 if (ers->lo > lo)
279 ers->lo = lo;
280 if (ers->hi < hi)
281 ers->hi = hi;
282 }
283
284 /*
285 * The inserted or revised range might overlap or abut adjacent ones;
286 * coalesce as necessary.
287 */
288
289 /* Check predecessors */
290 while ((crs = RB_PREV(revoked_serial_tree, rt, ers)) != NULL) {
291 KRL_DBG(("pred %llu:%llu", crs->lo, crs->hi));
292 if (ers->lo != 0 && crs->hi < ers->lo - 1)
293 break;
294 /* This entry overlaps. */
295 if (crs->lo < ers->lo) {
296 ers->lo = crs->lo;
297 KRL_DBG(("pred extend %llu:%llu", ers->lo, ers->hi));
298 }
299 RB_REMOVE(revoked_serial_tree, rt, crs);
300 free(crs);
301 }
302 /* Check successors */
303 while ((crs = RB_NEXT(revoked_serial_tree, rt, ers)) != NULL) {
304 KRL_DBG(("succ %llu:%llu", crs->lo, crs->hi));
305 if (ers->hi != (u_int64_t)-1 && crs->lo > ers->hi + 1)
306 break;
307 /* This entry overlaps. */
308 if (crs->hi > ers->hi) {
309 ers->hi = crs->hi;
310 KRL_DBG(("succ extend %llu:%llu", ers->lo, ers->hi));
311 }
312 RB_REMOVE(revoked_serial_tree, rt, crs);
313 free(crs);
314 }
315 KRL_DBG(("done, final %llu:%llu", ers->lo, ers->hi));
316 return 0;
317 }
318
319 int
ssh_krl_revoke_cert_by_serial(struct ssh_krl * krl,const struct sshkey * ca_key,u_int64_t serial)320 ssh_krl_revoke_cert_by_serial(struct ssh_krl *krl, const struct sshkey *ca_key,
321 u_int64_t serial)
322 {
323 return ssh_krl_revoke_cert_by_serial_range(krl, ca_key, serial, serial);
324 }
325
326 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)327 ssh_krl_revoke_cert_by_serial_range(struct ssh_krl *krl,
328 const struct sshkey *ca_key, u_int64_t lo, u_int64_t hi)
329 {
330 struct revoked_certs *rc;
331 int r;
332
333 if (lo > hi || lo == 0)
334 return SSH_ERR_INVALID_ARGUMENT;
335 if ((r = revoked_certs_for_ca_key(krl, ca_key, &rc, 1)) != 0)
336 return r;
337 return insert_serial_range(&rc->revoked_serials, lo, hi);
338 }
339
340 int
ssh_krl_revoke_cert_by_key_id(struct ssh_krl * krl,const struct sshkey * ca_key,const char * key_id)341 ssh_krl_revoke_cert_by_key_id(struct ssh_krl *krl, const struct sshkey *ca_key,
342 const char *key_id)
343 {
344 struct revoked_key_id *rki, *erki;
345 struct revoked_certs *rc;
346 int r;
347
348 if ((r = revoked_certs_for_ca_key(krl, ca_key, &rc, 1)) != 0)
349 return r;
350
351 KRL_DBG(("revoke %s", key_id));
352 if ((rki = calloc(1, sizeof(*rki))) == NULL ||
353 (rki->key_id = strdup(key_id)) == NULL) {
354 free(rki);
355 return SSH_ERR_ALLOC_FAIL;
356 }
357 erki = RB_INSERT(revoked_key_id_tree, &rc->revoked_key_ids, rki);
358 if (erki != NULL) {
359 free(rki->key_id);
360 free(rki);
361 }
362 return 0;
363 }
364
365 /* Convert "key" to a public key blob without any certificate information */
366 static int
plain_key_blob(const struct sshkey * key,u_char ** blob,size_t * blen)367 plain_key_blob(const struct sshkey *key, u_char **blob, size_t *blen)
368 {
369 struct sshkey *kcopy;
370 int r;
371
372 if ((r = sshkey_from_private(key, &kcopy)) != 0)
373 return r;
374 if (sshkey_is_cert(kcopy)) {
375 if ((r = sshkey_drop_cert(kcopy)) != 0) {
376 sshkey_free(kcopy);
377 return r;
378 }
379 }
380 r = sshkey_to_blob(kcopy, blob, blen);
381 sshkey_free(kcopy);
382 return r;
383 }
384
385 /* Revoke a key blob. Ownership of blob is transferred to the tree */
386 static int
revoke_blob(struct revoked_blob_tree * rbt,u_char * blob,size_t len)387 revoke_blob(struct revoked_blob_tree *rbt, u_char *blob, size_t len)
388 {
389 struct revoked_blob *rb, *erb;
390
391 if ((rb = calloc(1, sizeof(*rb))) == NULL)
392 return SSH_ERR_ALLOC_FAIL;
393 rb->blob = blob;
394 rb->len = len;
395 erb = RB_INSERT(revoked_blob_tree, rbt, rb);
396 if (erb != NULL) {
397 free(rb->blob);
398 free(rb);
399 }
400 return 0;
401 }
402
403 int
ssh_krl_revoke_key_explicit(struct ssh_krl * krl,const struct sshkey * key)404 ssh_krl_revoke_key_explicit(struct ssh_krl *krl, const struct sshkey *key)
405 {
406 u_char *blob;
407 size_t len;
408 int r;
409
410 debug3_f("revoke type %s", sshkey_type(key));
411 if ((r = plain_key_blob(key, &blob, &len)) != 0)
412 return r;
413 return revoke_blob(&krl->revoked_keys, blob, len);
414 }
415
416 static int
revoke_by_hash(struct revoked_blob_tree * target,const u_char * p,size_t len)417 revoke_by_hash(struct revoked_blob_tree *target, const u_char *p, size_t len)
418 {
419 u_char *blob;
420 int r;
421
422 /* need to copy hash, as revoke_blob steals ownership */
423 if ((blob = malloc(len)) == NULL)
424 return SSH_ERR_SYSTEM_ERROR;
425 memcpy(blob, p, len);
426 if ((r = revoke_blob(target, blob, len)) != 0) {
427 free(blob);
428 return r;
429 }
430 return 0;
431 }
432
433 int
ssh_krl_revoke_key_sha1(struct ssh_krl * krl,const u_char * p,size_t len)434 ssh_krl_revoke_key_sha1(struct ssh_krl *krl, const u_char *p, size_t len)
435 {
436 debug3_f("revoke by sha1");
437 if (len != 20)
438 return SSH_ERR_INVALID_FORMAT;
439 return revoke_by_hash(&krl->revoked_sha1s, p, len);
440 }
441
442 int
ssh_krl_revoke_key_sha256(struct ssh_krl * krl,const u_char * p,size_t len)443 ssh_krl_revoke_key_sha256(struct ssh_krl *krl, const u_char *p, size_t len)
444 {
445 debug3_f("revoke by sha256");
446 if (len != 32)
447 return SSH_ERR_INVALID_FORMAT;
448 return revoke_by_hash(&krl->revoked_sha256s, p, len);
449 }
450
451 int
ssh_krl_revoke_key(struct ssh_krl * krl,const struct sshkey * key)452 ssh_krl_revoke_key(struct ssh_krl *krl, const struct sshkey *key)
453 {
454 /* XXX replace with SHA256? */
455 if (!sshkey_is_cert(key))
456 return ssh_krl_revoke_key_explicit(krl, key);
457
458 if (key->cert->serial == 0) {
459 return ssh_krl_revoke_cert_by_key_id(krl,
460 key->cert->signature_key,
461 key->cert->key_id);
462 } else {
463 return ssh_krl_revoke_cert_by_serial(krl,
464 key->cert->signature_key,
465 key->cert->serial);
466 }
467 }
468
469 /*
470 * Select the most compact section type to emit next in a KRL based on
471 * the current section type, the run length of contiguous revoked serial
472 * numbers and the gaps from the last and to the next revoked serial.
473 * Applies a mostly-accurate bit cost model to select the section type
474 * that will minimise the size of the resultant KRL.
475 */
476 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)477 choose_next_state(int current_state, u_int64_t contig, int final,
478 u_int64_t last_gap, u_int64_t next_gap, int *force_new_section)
479 {
480 int new_state;
481 u_int64_t cost, cost_list, cost_range, cost_bitmap, cost_bitmap_restart;
482
483 /*
484 * Avoid unsigned overflows.
485 * The limits are high enough to avoid confusing the calculations.
486 */
487 contig = MINIMUM(contig, 1ULL<<31);
488 last_gap = MINIMUM(last_gap, 1ULL<<31);
489 next_gap = MINIMUM(next_gap, 1ULL<<31);
490
491 /*
492 * Calculate the cost to switch from the current state to candidates.
493 * NB. range sections only ever contain a single range, so their
494 * switching cost is independent of the current_state.
495 */
496 cost_list = cost_bitmap = cost_bitmap_restart = 0;
497 cost_range = 8;
498 switch (current_state) {
499 case KRL_SECTION_CERT_SERIAL_LIST:
500 cost_bitmap_restart = cost_bitmap = 8 + 64;
501 break;
502 case KRL_SECTION_CERT_SERIAL_BITMAP:
503 cost_list = 8;
504 cost_bitmap_restart = 8 + 64;
505 break;
506 case KRL_SECTION_CERT_SERIAL_RANGE:
507 case 0:
508 cost_bitmap_restart = cost_bitmap = 8 + 64;
509 cost_list = 8;
510 }
511
512 /* Estimate base cost in bits of each section type */
513 cost_list += 64 * contig + (final ? 0 : 8+64);
514 cost_range += (2 * 64) + (final ? 0 : 8+64);
515 cost_bitmap += last_gap + contig + (final ? 0 : MINIMUM(next_gap, 8+64));
516 cost_bitmap_restart += contig + (final ? 0 : MINIMUM(next_gap, 8+64));
517
518 /* Convert to byte costs for actual comparison */
519 cost_list = (cost_list + 7) / 8;
520 cost_bitmap = (cost_bitmap + 7) / 8;
521 cost_bitmap_restart = (cost_bitmap_restart + 7) / 8;
522 cost_range = (cost_range + 7) / 8;
523
524 /* Now pick the best choice */
525 *force_new_section = 0;
526 new_state = KRL_SECTION_CERT_SERIAL_BITMAP;
527 cost = cost_bitmap;
528 if (cost_range < cost) {
529 new_state = KRL_SECTION_CERT_SERIAL_RANGE;
530 cost = cost_range;
531 }
532 if (cost_list < cost) {
533 new_state = KRL_SECTION_CERT_SERIAL_LIST;
534 cost = cost_list;
535 }
536 if (cost_bitmap_restart < cost) {
537 new_state = KRL_SECTION_CERT_SERIAL_BITMAP;
538 *force_new_section = 1;
539 cost = cost_bitmap_restart;
540 }
541 KRL_DBG(("contig %llu last_gap %llu next_gap %llu final %d, costs:"
542 "list %llu range %llu bitmap %llu new bitmap %llu, "
543 "selected 0x%02x%s", (long long unsigned)contig,
544 (long long unsigned)last_gap, (long long unsigned)next_gap, final,
545 (long long unsigned)cost_list, (long long unsigned)cost_range,
546 (long long unsigned)cost_bitmap,
547 (long long unsigned)cost_bitmap_restart, new_state,
548 *force_new_section ? " restart" : ""));
549 return new_state;
550 }
551
552 static int
put_bitmap(struct sshbuf * buf,struct bitmap * bitmap)553 put_bitmap(struct sshbuf *buf, struct bitmap *bitmap)
554 {
555 size_t len;
556 u_char *blob;
557 int r;
558
559 len = bitmap_nbytes(bitmap);
560 if ((blob = malloc(len)) == NULL)
561 return SSH_ERR_ALLOC_FAIL;
562 if (bitmap_to_string(bitmap, blob, len) != 0) {
563 free(blob);
564 return SSH_ERR_INTERNAL_ERROR;
565 }
566 r = sshbuf_put_bignum2_bytes(buf, blob, len);
567 free(blob);
568 return r;
569 }
570
571 /* Generate a KRL_SECTION_CERTIFICATES KRL section */
572 static int
revoked_certs_generate(struct revoked_certs * rc,struct sshbuf * buf)573 revoked_certs_generate(struct revoked_certs *rc, struct sshbuf *buf)
574 {
575 int final, force_new_sect, r = SSH_ERR_INTERNAL_ERROR;
576 u_int64_t i, contig, gap, last = 0, bitmap_start = 0;
577 struct revoked_serial *rs, *nrs;
578 struct revoked_key_id *rki;
579 int next_state, state = 0;
580 struct sshbuf *sect;
581 struct bitmap *bitmap = NULL;
582
583 if ((sect = sshbuf_new()) == NULL)
584 return SSH_ERR_ALLOC_FAIL;
585
586 /* Store the header: optional CA scope key, reserved */
587 if (rc->ca_key == NULL) {
588 if ((r = sshbuf_put_string(buf, NULL, 0)) != 0)
589 goto out;
590 } else {
591 if ((r = sshkey_puts(rc->ca_key, buf)) != 0)
592 goto out;
593 }
594 if ((r = sshbuf_put_string(buf, NULL, 0)) != 0)
595 goto out;
596
597 /* Store the revoked serials. */
598 for (rs = RB_MIN(revoked_serial_tree, &rc->revoked_serials);
599 rs != NULL;
600 rs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs)) {
601 KRL_DBG(("serial %llu:%llu state 0x%02x",
602 (long long unsigned)rs->lo, (long long unsigned)rs->hi,
603 state));
604
605 /* Check contiguous length and gap to next section (if any) */
606 nrs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs);
607 final = nrs == NULL;
608 gap = nrs == NULL ? 0 : nrs->lo - rs->hi;
609 contig = 1 + (rs->hi - rs->lo);
610
611 /* Choose next state based on these */
612 next_state = choose_next_state(state, contig, final,
613 state == 0 ? 0 : rs->lo - last, gap, &force_new_sect);
614
615 /*
616 * If the current section is a range section or has a different
617 * type to the next section, then finish it off now.
618 */
619 if (state != 0 && (force_new_sect || next_state != state ||
620 state == KRL_SECTION_CERT_SERIAL_RANGE)) {
621 KRL_DBG(("finish state 0x%02x", state));
622 switch (state) {
623 case KRL_SECTION_CERT_SERIAL_LIST:
624 case KRL_SECTION_CERT_SERIAL_RANGE:
625 break;
626 case KRL_SECTION_CERT_SERIAL_BITMAP:
627 if ((r = put_bitmap(sect, bitmap)) != 0)
628 goto out;
629 bitmap_free(bitmap);
630 bitmap = NULL;
631 break;
632 }
633 if ((r = sshbuf_put_u8(buf, state)) != 0 ||
634 (r = sshbuf_put_stringb(buf, sect)) != 0)
635 goto out;
636 sshbuf_reset(sect);
637 }
638
639 /* If we are starting a new section then prepare it now */
640 if (next_state != state || force_new_sect) {
641 KRL_DBG(("start state 0x%02x",
642 next_state));
643 state = next_state;
644 sshbuf_reset(sect);
645 switch (state) {
646 case KRL_SECTION_CERT_SERIAL_LIST:
647 case KRL_SECTION_CERT_SERIAL_RANGE:
648 break;
649 case KRL_SECTION_CERT_SERIAL_BITMAP:
650 if ((bitmap = bitmap_new()) == NULL) {
651 r = SSH_ERR_ALLOC_FAIL;
652 goto out;
653 }
654 bitmap_start = rs->lo;
655 if ((r = sshbuf_put_u64(sect,
656 bitmap_start)) != 0)
657 goto out;
658 break;
659 }
660 }
661
662 /* Perform section-specific processing */
663 switch (state) {
664 case KRL_SECTION_CERT_SERIAL_LIST:
665 for (i = 0; i < contig; i++) {
666 if ((r = sshbuf_put_u64(sect, rs->lo + i)) != 0)
667 goto out;
668 }
669 break;
670 case KRL_SECTION_CERT_SERIAL_RANGE:
671 if ((r = sshbuf_put_u64(sect, rs->lo)) != 0 ||
672 (r = sshbuf_put_u64(sect, rs->hi)) != 0)
673 goto out;
674 break;
675 case KRL_SECTION_CERT_SERIAL_BITMAP:
676 if (rs->lo - bitmap_start > INT_MAX) {
677 error_f("insane bitmap gap");
678 goto out;
679 }
680 for (i = 0; i < contig; i++) {
681 if (bitmap_set_bit(bitmap,
682 rs->lo + i - bitmap_start) != 0) {
683 r = SSH_ERR_ALLOC_FAIL;
684 goto out;
685 }
686 }
687 break;
688 }
689 last = rs->hi;
690 }
691 /* Flush the remaining section, if any */
692 if (state != 0) {
693 KRL_DBG(("serial final flush for state 0x%02x", state));
694 switch (state) {
695 case KRL_SECTION_CERT_SERIAL_LIST:
696 case KRL_SECTION_CERT_SERIAL_RANGE:
697 break;
698 case KRL_SECTION_CERT_SERIAL_BITMAP:
699 if ((r = put_bitmap(sect, bitmap)) != 0)
700 goto out;
701 bitmap_free(bitmap);
702 bitmap = NULL;
703 break;
704 }
705 if ((r = sshbuf_put_u8(buf, state)) != 0 ||
706 (r = sshbuf_put_stringb(buf, sect)) != 0)
707 goto out;
708 }
709 KRL_DBG(("serial done "));
710
711 /* Now output a section for any revocations by key ID */
712 sshbuf_reset(sect);
713 RB_FOREACH(rki, revoked_key_id_tree, &rc->revoked_key_ids) {
714 KRL_DBG(("key ID %s", rki->key_id));
715 if ((r = sshbuf_put_cstring(sect, rki->key_id)) != 0)
716 goto out;
717 }
718 if (sshbuf_len(sect) != 0) {
719 if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERT_KEY_ID)) != 0 ||
720 (r = sshbuf_put_stringb(buf, sect)) != 0)
721 goto out;
722 }
723 r = 0;
724 out:
725 bitmap_free(bitmap);
726 sshbuf_free(sect);
727 return r;
728 }
729
730 int
ssh_krl_to_blob(struct ssh_krl * krl,struct sshbuf * buf)731 ssh_krl_to_blob(struct ssh_krl *krl, struct sshbuf *buf)
732 {
733 int r = SSH_ERR_INTERNAL_ERROR;
734 struct revoked_certs *rc;
735 struct revoked_blob *rb;
736 struct sshbuf *sect;
737 u_char *sblob = NULL;
738
739 if (krl->generated_date == 0)
740 krl->generated_date = time(NULL);
741
742 if ((sect = sshbuf_new()) == NULL)
743 return SSH_ERR_ALLOC_FAIL;
744
745 /* Store the header */
746 if ((r = sshbuf_put(buf, KRL_MAGIC, sizeof(KRL_MAGIC) - 1)) != 0 ||
747 (r = sshbuf_put_u32(buf, KRL_FORMAT_VERSION)) != 0 ||
748 (r = sshbuf_put_u64(buf, krl->krl_version)) != 0 ||
749 (r = sshbuf_put_u64(buf, krl->generated_date)) != 0 ||
750 (r = sshbuf_put_u64(buf, krl->flags)) != 0 ||
751 (r = sshbuf_put_string(buf, NULL, 0)) != 0 ||
752 (r = sshbuf_put_cstring(buf, krl->comment)) != 0)
753 goto out;
754
755 /* Store sections for revoked certificates */
756 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) {
757 sshbuf_reset(sect);
758 if ((r = revoked_certs_generate(rc, sect)) != 0)
759 goto out;
760 if ((r = sshbuf_put_u8(buf, KRL_SECTION_CERTIFICATES)) != 0 ||
761 (r = sshbuf_put_stringb(buf, sect)) != 0)
762 goto out;
763 }
764
765 /* Finally, output sections for revocations by public key/hash */
766 sshbuf_reset(sect);
767 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_keys) {
768 KRL_DBG(("key len %zu ", rb->len));
769 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0)
770 goto out;
771 }
772 if (sshbuf_len(sect) != 0) {
773 if ((r = sshbuf_put_u8(buf, KRL_SECTION_EXPLICIT_KEY)) != 0 ||
774 (r = sshbuf_put_stringb(buf, sect)) != 0)
775 goto out;
776 }
777 sshbuf_reset(sect);
778 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha1s) {
779 KRL_DBG(("hash len %zu ", rb->len));
780 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0)
781 goto out;
782 }
783 if (sshbuf_len(sect) != 0) {
784 if ((r = sshbuf_put_u8(buf,
785 KRL_SECTION_FINGERPRINT_SHA1)) != 0 ||
786 (r = sshbuf_put_stringb(buf, sect)) != 0)
787 goto out;
788 }
789 sshbuf_reset(sect);
790 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha256s) {
791 KRL_DBG(("hash len %zu ", rb->len));
792 if ((r = sshbuf_put_string(sect, rb->blob, rb->len)) != 0)
793 goto out;
794 }
795 if (sshbuf_len(sect) != 0) {
796 if ((r = sshbuf_put_u8(buf,
797 KRL_SECTION_FINGERPRINT_SHA256)) != 0 ||
798 (r = sshbuf_put_stringb(buf, sect)) != 0)
799 goto out;
800 }
801 /* success */
802 r = 0;
803 out:
804 free(sblob);
805 sshbuf_free(sect);
806 return r;
807 }
808
809 static void
format_timestamp(u_int64_t timestamp,char * ts,size_t nts)810 format_timestamp(u_int64_t timestamp, char *ts, size_t nts)
811 {
812 time_t t;
813 struct tm *tm;
814
815 t = timestamp;
816 tm = localtime(&t);
817 if (tm == NULL)
818 strlcpy(ts, "<INVALID>", nts);
819 else {
820 *ts = '\0';
821 strftime(ts, nts, "%Y%m%dT%H%M%S", tm);
822 }
823 }
824
825 static int
cert_extension_subsection(struct sshbuf * subsect,struct ssh_krl * krl)826 cert_extension_subsection(struct sshbuf *subsect, struct ssh_krl *krl)
827 {
828 int r = SSH_ERR_INTERNAL_ERROR;
829 u_char critical = 1;
830 struct sshbuf *value = NULL;
831 char *name = NULL;
832
833 if ((r = sshbuf_get_cstring(subsect, &name, NULL)) != 0 ||
834 (r = sshbuf_get_u8(subsect, &critical)) != 0 ||
835 (r = sshbuf_froms(subsect, &value)) != 0) {
836 debug_fr(r, "parse");
837 error("KRL has invalid certificate extension subsection");
838 r = SSH_ERR_INVALID_FORMAT;
839 goto out;
840 }
841 if (sshbuf_len(subsect) != 0) {
842 error("KRL has invalid certificate extension subsection: "
843 "trailing data");
844 r = SSH_ERR_INVALID_FORMAT;
845 goto out;
846 }
847 debug_f("cert extension %s critical %u len %zu",
848 name, critical, sshbuf_len(value));
849 /* no extensions are currently supported */
850 if (critical) {
851 error("KRL contains unsupported critical certificate "
852 "subsection \"%s\"", name);
853 r = SSH_ERR_FEATURE_UNSUPPORTED;
854 goto out;
855 }
856 /* success */
857 r = 0;
858 out:
859 free(name);
860 sshbuf_free(value);
861 return r;
862 }
863
864 static int
parse_revoked_certs(struct sshbuf * buf,struct ssh_krl * krl)865 parse_revoked_certs(struct sshbuf *buf, struct ssh_krl *krl)
866 {
867 int r = SSH_ERR_INTERNAL_ERROR;
868 u_char type;
869 const u_char *blob;
870 size_t blen, nbits;
871 struct sshbuf *subsect = NULL;
872 u_int64_t serial, serial_lo, serial_hi;
873 struct bitmap *bitmap = NULL;
874 char *key_id = NULL;
875 struct sshkey *ca_key = NULL;
876
877 if ((subsect = sshbuf_new()) == NULL)
878 return SSH_ERR_ALLOC_FAIL;
879
880 /* Header: key, reserved */
881 if ((r = sshbuf_get_string_direct(buf, &blob, &blen)) != 0 ||
882 (r = sshbuf_skip_string(buf)) != 0)
883 goto out;
884 if (blen != 0 && (r = sshkey_from_blob(blob, blen, &ca_key)) != 0)
885 goto out;
886
887 while (sshbuf_len(buf) > 0) {
888 sshbuf_free(subsect);
889 subsect = NULL;
890 if ((r = sshbuf_get_u8(buf, &type)) != 0 ||
891 (r = sshbuf_froms(buf, &subsect)) != 0)
892 goto out;
893 KRL_DBG(("subsection type 0x%02x", type));
894 /* sshbuf_dump(subsect, stderr); */
895
896 switch (type) {
897 case KRL_SECTION_CERT_SERIAL_LIST:
898 while (sshbuf_len(subsect) > 0) {
899 if ((r = sshbuf_get_u64(subsect, &serial)) != 0)
900 goto out;
901 if ((r = ssh_krl_revoke_cert_by_serial(krl,
902 ca_key, serial)) != 0)
903 goto out;
904 }
905 break;
906 case KRL_SECTION_CERT_SERIAL_RANGE:
907 if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 ||
908 (r = sshbuf_get_u64(subsect, &serial_hi)) != 0)
909 goto out;
910 if ((r = ssh_krl_revoke_cert_by_serial_range(krl,
911 ca_key, serial_lo, serial_hi)) != 0)
912 goto out;
913 break;
914 case KRL_SECTION_CERT_SERIAL_BITMAP:
915 if ((bitmap = bitmap_new()) == NULL) {
916 r = SSH_ERR_ALLOC_FAIL;
917 goto out;
918 }
919 if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 ||
920 (r = sshbuf_get_bignum2_bytes_direct(subsect,
921 &blob, &blen)) != 0)
922 goto out;
923 if (bitmap_from_string(bitmap, blob, blen) != 0) {
924 r = SSH_ERR_INVALID_FORMAT;
925 goto out;
926 }
927 nbits = bitmap_nbits(bitmap);
928 for (serial = 0; serial < (u_int64_t)nbits; serial++) {
929 if (serial > 0 && serial_lo + serial == 0) {
930 error_f("bitmap wraps u64");
931 r = SSH_ERR_INVALID_FORMAT;
932 goto out;
933 }
934 if (!bitmap_test_bit(bitmap, serial))
935 continue;
936 if ((r = ssh_krl_revoke_cert_by_serial(krl,
937 ca_key, serial_lo + serial)) != 0)
938 goto out;
939 }
940 bitmap_free(bitmap);
941 bitmap = NULL;
942 break;
943 case KRL_SECTION_CERT_KEY_ID:
944 while (sshbuf_len(subsect) > 0) {
945 if ((r = sshbuf_get_cstring(subsect,
946 &key_id, NULL)) != 0)
947 goto out;
948 if ((r = ssh_krl_revoke_cert_by_key_id(krl,
949 ca_key, key_id)) != 0)
950 goto out;
951 free(key_id);
952 key_id = NULL;
953 }
954 break;
955 case KRL_SECTION_CERT_EXTENSION:
956 if ((r = cert_extension_subsection(subsect, krl)) != 0)
957 goto out;
958 break;
959 default:
960 error("Unsupported KRL certificate section %u", type);
961 r = SSH_ERR_INVALID_FORMAT;
962 goto out;
963 }
964 if (sshbuf_len(subsect) > 0) {
965 error("KRL certificate section contains unparsed data");
966 r = SSH_ERR_INVALID_FORMAT;
967 goto out;
968 }
969 }
970
971 r = 0;
972 out:
973 if (bitmap != NULL)
974 bitmap_free(bitmap);
975 free(key_id);
976 sshkey_free(ca_key);
977 sshbuf_free(subsect);
978 return r;
979 }
980
981 static int
blob_section(struct sshbuf * sect,struct revoked_blob_tree * target_tree,size_t expected_len)982 blob_section(struct sshbuf *sect, struct revoked_blob_tree *target_tree,
983 size_t expected_len)
984 {
985 u_char *rdata = NULL;
986 size_t rlen = 0;
987 int r;
988
989 while (sshbuf_len(sect) > 0) {
990 if ((r = sshbuf_get_string(sect, &rdata, &rlen)) != 0)
991 return r;
992 if (expected_len != 0 && rlen != expected_len) {
993 error_f("bad length");
994 free(rdata);
995 return SSH_ERR_INVALID_FORMAT;
996 }
997 if ((r = revoke_blob(target_tree, rdata, rlen)) != 0) {
998 free(rdata);
999 return r;
1000 }
1001 }
1002 return 0;
1003 }
1004
1005 static int
extension_section(struct sshbuf * sect,struct ssh_krl * krl)1006 extension_section(struct sshbuf *sect, struct ssh_krl *krl)
1007 {
1008 int r = SSH_ERR_INTERNAL_ERROR;
1009 u_char critical = 1;
1010 struct sshbuf *value = NULL;
1011 char *name = NULL;
1012
1013 if ((r = sshbuf_get_cstring(sect, &name, NULL)) != 0 ||
1014 (r = sshbuf_get_u8(sect, &critical)) != 0 ||
1015 (r = sshbuf_froms(sect, &value)) != 0) {
1016 debug_fr(r, "parse");
1017 error("KRL has invalid extension section");
1018 r = SSH_ERR_INVALID_FORMAT;
1019 goto out;
1020 }
1021 if (sshbuf_len(sect) != 0) {
1022 error("KRL has invalid extension section: trailing data");
1023 r = SSH_ERR_INVALID_FORMAT;
1024 goto out;
1025 }
1026 debug_f("extension %s critical %u len %zu",
1027 name, critical, sshbuf_len(value));
1028 /* no extensions are currently supported */
1029 if (critical) {
1030 error("KRL contains unsupported critical section \"%s\"", name);
1031 r = SSH_ERR_FEATURE_UNSUPPORTED;
1032 goto out;
1033 }
1034 /* success */
1035 r = 0;
1036 out:
1037 free(name);
1038 sshbuf_free(value);
1039 return r;
1040 }
1041
1042 /* Attempt to parse a KRL */
1043 int
ssh_krl_from_blob(struct sshbuf * buf,struct ssh_krl ** krlp)1044 ssh_krl_from_blob(struct sshbuf *buf, struct ssh_krl **krlp)
1045 {
1046 struct sshbuf *copy = NULL, *sect = NULL;
1047 struct ssh_krl *krl = NULL;
1048 char timestamp[64];
1049 int r = SSH_ERR_INTERNAL_ERROR;
1050 u_char type;
1051 u_int format_version;
1052
1053 *krlp = NULL;
1054
1055 /* KRL must begin with magic string */
1056 if ((r = sshbuf_cmp(buf, 0, KRL_MAGIC, sizeof(KRL_MAGIC) - 1)) != 0) {
1057 debug2_f("bad KRL magic header");
1058 return SSH_ERR_KRL_BAD_MAGIC;
1059 }
1060
1061 if ((krl = ssh_krl_init()) == NULL) {
1062 error_f("alloc failed");
1063 goto out;
1064 }
1065 /* Don't modify buffer */
1066 if ((copy = sshbuf_fromb(buf)) == NULL) {
1067 r = SSH_ERR_ALLOC_FAIL;
1068 goto out;
1069 }
1070 if ((r = sshbuf_consume(copy, sizeof(KRL_MAGIC) - 1)) != 0 ||
1071 (r = sshbuf_get_u32(copy, &format_version)) != 0)
1072 goto out;
1073 if (format_version != KRL_FORMAT_VERSION) {
1074 error_f("unsupported KRL format version %u", format_version);
1075 r = SSH_ERR_INVALID_FORMAT;
1076 goto out;
1077 }
1078 if ((r = sshbuf_get_u64(copy, &krl->krl_version)) != 0 ||
1079 (r = sshbuf_get_u64(copy, &krl->generated_date)) != 0 ||
1080 (r = sshbuf_get_u64(copy, &krl->flags)) != 0 ||
1081 (r = sshbuf_skip_string(copy)) != 0 ||
1082 (r = sshbuf_get_cstring(copy, &krl->comment, NULL)) != 0) {
1083 error_fr(r, "parse KRL header");
1084 goto out;
1085 }
1086 format_timestamp(krl->generated_date, timestamp, sizeof(timestamp));
1087 debug("KRL version %llu generated at %s%s%s",
1088 (long long unsigned)krl->krl_version, timestamp,
1089 *krl->comment ? ": " : "", krl->comment);
1090
1091 /* Parse and load the KRL sections. */
1092 while (sshbuf_len(copy) > 0) {
1093 sshbuf_free(sect);
1094 sect = NULL;
1095 if ((r = sshbuf_get_u8(copy, &type)) != 0 ||
1096 (r = sshbuf_froms(copy, §)) != 0)
1097 goto out;
1098 KRL_DBG(("section 0x%02x", type));
1099
1100 switch (type) {
1101 case KRL_SECTION_CERTIFICATES:
1102 if ((r = parse_revoked_certs(sect, krl)) != 0)
1103 goto out;
1104 break;
1105 case KRL_SECTION_EXPLICIT_KEY:
1106 if ((r = blob_section(sect,
1107 &krl->revoked_keys, 0)) != 0)
1108 goto out;
1109 break;
1110 case KRL_SECTION_FINGERPRINT_SHA1:
1111 if ((r = blob_section(sect,
1112 &krl->revoked_sha1s, 20)) != 0)
1113 goto out;
1114 break;
1115 case KRL_SECTION_FINGERPRINT_SHA256:
1116 if ((r = blob_section(sect,
1117 &krl->revoked_sha256s, 32)) != 0)
1118 goto out;
1119 break;
1120 case KRL_SECTION_EXTENSION:
1121 if ((r = extension_section(sect, krl)) != 0)
1122 goto out;
1123 break;
1124 case KRL_SECTION_SIGNATURE:
1125 /* Handled above, but still need to stay in synch */
1126 sshbuf_free(sect);
1127 sect = NULL;
1128 if ((r = sshbuf_skip_string(copy)) != 0)
1129 goto out;
1130 break;
1131 default:
1132 error("Unsupported KRL section %u", type);
1133 r = SSH_ERR_INVALID_FORMAT;
1134 goto out;
1135 }
1136 if (sect != NULL && sshbuf_len(sect) > 0) {
1137 error("KRL section contains unparsed data");
1138 r = SSH_ERR_INVALID_FORMAT;
1139 goto out;
1140 }
1141 }
1142
1143 /* Success */
1144 *krlp = krl;
1145 r = 0;
1146 out:
1147 if (r != 0)
1148 ssh_krl_free(krl);
1149 sshbuf_free(copy);
1150 sshbuf_free(sect);
1151 return r;
1152 }
1153
1154 /* Checks certificate serial number and key ID revocation */
1155 static int
is_cert_revoked(const struct sshkey * key,struct revoked_certs * rc)1156 is_cert_revoked(const struct sshkey *key, struct revoked_certs *rc)
1157 {
1158 struct revoked_serial rs, *ers;
1159 struct revoked_key_id rki, *erki;
1160
1161 /* Check revocation by cert key ID */
1162 memset(&rki, 0, sizeof(rki));
1163 rki.key_id = key->cert->key_id;
1164 erki = RB_FIND(revoked_key_id_tree, &rc->revoked_key_ids, &rki);
1165 if (erki != NULL) {
1166 KRL_DBG(("revoked by key ID"));
1167 return SSH_ERR_KEY_REVOKED;
1168 }
1169
1170 /*
1171 * Zero serials numbers are ignored (it's the default when the
1172 * CA doesn't specify one).
1173 */
1174 if (key->cert->serial == 0)
1175 return 0;
1176
1177 memset(&rs, 0, sizeof(rs));
1178 rs.lo = rs.hi = key->cert->serial;
1179 ers = RB_FIND(revoked_serial_tree, &rc->revoked_serials, &rs);
1180 if (ers != NULL) {
1181 KRL_DBG(("revoked serial %llu matched %llu:%llu",
1182 key->cert->serial, ers->lo, ers->hi));
1183 return SSH_ERR_KEY_REVOKED;
1184 }
1185 return 0;
1186 }
1187
1188 /* Checks whether a given key/cert is revoked. Does not check its CA */
1189 static int
is_key_revoked(struct ssh_krl * krl,const struct sshkey * key)1190 is_key_revoked(struct ssh_krl *krl, const struct sshkey *key)
1191 {
1192 struct revoked_blob rb, *erb;
1193 struct revoked_certs *rc;
1194 int r;
1195
1196 /* Check explicitly revoked hashes first */
1197 memset(&rb, 0, sizeof(rb));
1198 if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA1,
1199 &rb.blob, &rb.len)) != 0)
1200 return r;
1201 erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha1s, &rb);
1202 free(rb.blob);
1203 if (erb != NULL) {
1204 KRL_DBG(("revoked by key SHA1"));
1205 return SSH_ERR_KEY_REVOKED;
1206 }
1207 memset(&rb, 0, sizeof(rb));
1208 if ((r = sshkey_fingerprint_raw(key, SSH_DIGEST_SHA256,
1209 &rb.blob, &rb.len)) != 0)
1210 return r;
1211 erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha256s, &rb);
1212 free(rb.blob);
1213 if (erb != NULL) {
1214 KRL_DBG(("revoked by key SHA256"));
1215 return SSH_ERR_KEY_REVOKED;
1216 }
1217
1218 /* Next, explicit keys */
1219 memset(&rb, 0, sizeof(rb));
1220 if ((r = plain_key_blob(key, &rb.blob, &rb.len)) != 0)
1221 return r;
1222 erb = RB_FIND(revoked_blob_tree, &krl->revoked_keys, &rb);
1223 free(rb.blob);
1224 if (erb != NULL) {
1225 KRL_DBG(("revoked by explicit key"));
1226 return SSH_ERR_KEY_REVOKED;
1227 }
1228
1229 if (!sshkey_is_cert(key))
1230 return 0;
1231
1232 /* Check cert revocation for the specified CA */
1233 if ((r = revoked_certs_for_ca_key(krl, key->cert->signature_key,
1234 &rc, 0)) != 0)
1235 return r;
1236 if (rc != NULL) {
1237 if ((r = is_cert_revoked(key, rc)) != 0)
1238 return r;
1239 }
1240 /* Check cert revocation for the wildcard CA */
1241 if ((r = revoked_certs_for_ca_key(krl, NULL, &rc, 0)) != 0)
1242 return r;
1243 if (rc != NULL) {
1244 if ((r = is_cert_revoked(key, rc)) != 0)
1245 return r;
1246 }
1247
1248 KRL_DBG(("%llu no match", key->cert->serial));
1249 return 0;
1250 }
1251
1252 int
ssh_krl_check_key(struct ssh_krl * krl,const struct sshkey * key)1253 ssh_krl_check_key(struct ssh_krl *krl, const struct sshkey *key)
1254 {
1255 int r;
1256
1257 KRL_DBG(("checking key"));
1258 if ((r = is_key_revoked(krl, key)) != 0)
1259 return r;
1260 if (sshkey_is_cert(key)) {
1261 debug2_f("checking CA key");
1262 if ((r = is_key_revoked(krl, key->cert->signature_key)) != 0)
1263 return r;
1264 }
1265 KRL_DBG(("key okay"));
1266 return 0;
1267 }
1268
1269 int
ssh_krl_file_contains_key(const char * path,const struct sshkey * key)1270 ssh_krl_file_contains_key(const char *path, const struct sshkey *key)
1271 {
1272 struct sshbuf *krlbuf = NULL;
1273 struct ssh_krl *krl = NULL;
1274 int oerrno = 0, r;
1275
1276 if (path == NULL)
1277 return 0;
1278 if ((r = sshbuf_load_file(path, &krlbuf)) != 0) {
1279 oerrno = errno;
1280 goto out;
1281 }
1282 if ((r = ssh_krl_from_blob(krlbuf, &krl)) != 0)
1283 goto out;
1284 debug2_f("checking KRL %s", path);
1285 r = ssh_krl_check_key(krl, key);
1286 out:
1287 sshbuf_free(krlbuf);
1288 ssh_krl_free(krl);
1289 if (r != 0)
1290 errno = oerrno;
1291 return r;
1292 }
1293
1294 int
krl_dump(struct ssh_krl * krl,FILE * f)1295 krl_dump(struct ssh_krl *krl, FILE *f)
1296 {
1297 struct sshkey *key = NULL;
1298 struct revoked_blob *rb;
1299 struct revoked_certs *rc;
1300 struct revoked_serial *rs;
1301 struct revoked_key_id *rki;
1302 int r, ret = 0;
1303 char *fp, timestamp[64];
1304
1305 /* Try to print in a KRL spec-compatible format */
1306 format_timestamp(krl->generated_date, timestamp, sizeof(timestamp));
1307 fprintf(f, "# KRL version %llu\n",
1308 (unsigned long long)krl->krl_version);
1309 fprintf(f, "# Generated at %s\n", timestamp);
1310 if (krl->comment != NULL && *krl->comment != '\0') {
1311 r = INT_MAX;
1312 asmprintf(&fp, INT_MAX, &r, "%s", krl->comment);
1313 fprintf(f, "# Comment: %s\n", fp);
1314 free(fp);
1315 }
1316 fputc('\n', f);
1317
1318 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_keys) {
1319 if ((r = sshkey_from_blob(rb->blob, rb->len, &key)) != 0) {
1320 ret = SSH_ERR_INVALID_FORMAT;
1321 error_r(r, "parse KRL key");
1322 continue;
1323 }
1324 if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT,
1325 SSH_FP_DEFAULT)) == NULL) {
1326 ret = SSH_ERR_INVALID_FORMAT;
1327 error("sshkey_fingerprint failed");
1328 continue;
1329 }
1330 fprintf(f, "hash: %s # %s\n", fp, sshkey_ssh_name(key));
1331 free(fp);
1332 free(key);
1333 }
1334 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha256s) {
1335 fp = tohex(rb->blob, rb->len);
1336 fprintf(f, "hash: SHA256:%s\n", fp);
1337 free(fp);
1338 }
1339 RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha1s) {
1340 /*
1341 * There is not KRL spec keyword for raw SHA1 hashes, so
1342 * print them as comments.
1343 */
1344 fp = tohex(rb->blob, rb->len);
1345 fprintf(f, "# hash SHA1:%s\n", fp);
1346 free(fp);
1347 }
1348
1349 TAILQ_FOREACH(rc, &krl->revoked_certs, entry) {
1350 fputc('\n', f);
1351 if (rc->ca_key == NULL)
1352 fprintf(f, "# Wildcard CA\n");
1353 else {
1354 if ((fp = sshkey_fingerprint(rc->ca_key,
1355 SSH_FP_HASH_DEFAULT, SSH_FP_DEFAULT)) == NULL) {
1356 ret = SSH_ERR_INVALID_FORMAT;
1357 error("sshkey_fingerprint failed");
1358 continue;
1359 }
1360 fprintf(f, "# CA key %s %s\n",
1361 sshkey_ssh_name(rc->ca_key), fp);
1362 free(fp);
1363 }
1364 RB_FOREACH(rs, revoked_serial_tree, &rc->revoked_serials) {
1365 if (rs->lo == rs->hi) {
1366 fprintf(f, "serial: %llu\n",
1367 (unsigned long long)rs->lo);
1368 } else {
1369 fprintf(f, "serial: %llu-%llu\n",
1370 (unsigned long long)rs->lo,
1371 (unsigned long long)rs->hi);
1372 }
1373 }
1374 RB_FOREACH(rki, revoked_key_id_tree, &rc->revoked_key_ids) {
1375 /*
1376 * We don't want key IDs with embedded newlines to
1377 * mess up the display.
1378 */
1379 r = INT_MAX;
1380 asmprintf(&fp, INT_MAX, &r, "%s", rki->key_id);
1381 fprintf(f, "id: %s\n", fp);
1382 free(fp);
1383 }
1384 }
1385 return ret;
1386 }
1387