Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 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 | |
Darren Tucker | f3c3814 | 2013-04-05 11:16:52 +1100 | [diff] [blame] | 17 | /* $OpenBSD: krl.c,v 1.10 2013/02/19 02:12:47 dtucker Exp $ */ |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 18 | |
| 19 | #include "includes.h" |
| 20 | |
| 21 | #include <sys/types.h> |
| 22 | #include <sys/param.h> |
Damien Miller | d60b210 | 2013-01-20 22:49:58 +1100 | [diff] [blame] | 23 | #include <openbsd-compat/sys-tree.h> |
| 24 | #include <openbsd-compat/sys-queue.h> |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 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 "buffer.h" |
| 34 | #include "key.h" |
| 35 | #include "authfile.h" |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 36 | #include "misc.h" |
| 37 | #include "log.h" |
| 38 | #include "xmalloc.h" |
| 39 | |
| 40 | #include "krl.h" |
| 41 | |
| 42 | /* #define DEBUG_KRL */ |
| 43 | #ifdef DEBUG_KRL |
| 44 | # define KRL_DBG(x) debug3 x |
| 45 | #else |
| 46 | # define KRL_DBG(x) |
| 47 | #endif |
| 48 | |
| 49 | /* |
| 50 | * Trees of revoked serial numbers, key IDs and keys. This allows |
| 51 | * quick searching, querying and producing lists in canonical order. |
| 52 | */ |
| 53 | |
| 54 | /* Tree of serial numbers. XXX make smarter: really need a real sparse bitmap */ |
| 55 | struct revoked_serial { |
| 56 | u_int64_t lo, hi; |
| 57 | RB_ENTRY(revoked_serial) tree_entry; |
| 58 | }; |
| 59 | static int serial_cmp(struct revoked_serial *a, struct revoked_serial *b); |
| 60 | RB_HEAD(revoked_serial_tree, revoked_serial); |
| 61 | RB_GENERATE_STATIC(revoked_serial_tree, revoked_serial, tree_entry, serial_cmp); |
| 62 | |
| 63 | /* Tree of key IDs */ |
| 64 | struct revoked_key_id { |
| 65 | char *key_id; |
| 66 | RB_ENTRY(revoked_key_id) tree_entry; |
| 67 | }; |
| 68 | static int key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b); |
| 69 | RB_HEAD(revoked_key_id_tree, revoked_key_id); |
| 70 | RB_GENERATE_STATIC(revoked_key_id_tree, revoked_key_id, tree_entry, key_id_cmp); |
| 71 | |
| 72 | /* Tree of blobs (used for keys and fingerprints) */ |
| 73 | struct revoked_blob { |
| 74 | u_char *blob; |
| 75 | u_int len; |
| 76 | RB_ENTRY(revoked_blob) tree_entry; |
| 77 | }; |
| 78 | static int blob_cmp(struct revoked_blob *a, struct revoked_blob *b); |
| 79 | RB_HEAD(revoked_blob_tree, revoked_blob); |
| 80 | RB_GENERATE_STATIC(revoked_blob_tree, revoked_blob, tree_entry, blob_cmp); |
| 81 | |
| 82 | /* Tracks revoked certs for a single CA */ |
| 83 | struct revoked_certs { |
| 84 | Key *ca_key; |
| 85 | struct revoked_serial_tree revoked_serials; |
| 86 | struct revoked_key_id_tree revoked_key_ids; |
| 87 | TAILQ_ENTRY(revoked_certs) entry; |
| 88 | }; |
| 89 | TAILQ_HEAD(revoked_certs_list, revoked_certs); |
| 90 | |
| 91 | struct ssh_krl { |
| 92 | u_int64_t krl_version; |
| 93 | u_int64_t generated_date; |
| 94 | u_int64_t flags; |
| 95 | char *comment; |
| 96 | struct revoked_blob_tree revoked_keys; |
| 97 | struct revoked_blob_tree revoked_sha1s; |
| 98 | struct revoked_certs_list revoked_certs; |
| 99 | }; |
| 100 | |
| 101 | /* Return equal if a and b overlap */ |
| 102 | static int |
| 103 | serial_cmp(struct revoked_serial *a, struct revoked_serial *b) |
| 104 | { |
| 105 | if (a->hi >= b->lo && a->lo <= b->hi) |
| 106 | return 0; |
| 107 | return a->lo < b->lo ? -1 : 1; |
| 108 | } |
| 109 | |
| 110 | static int |
| 111 | key_id_cmp(struct revoked_key_id *a, struct revoked_key_id *b) |
| 112 | { |
| 113 | return strcmp(a->key_id, b->key_id); |
| 114 | } |
| 115 | |
| 116 | static int |
| 117 | blob_cmp(struct revoked_blob *a, struct revoked_blob *b) |
| 118 | { |
| 119 | int r; |
| 120 | |
| 121 | if (a->len != b->len) { |
| 122 | if ((r = memcmp(a->blob, b->blob, MIN(a->len, b->len))) != 0) |
| 123 | return r; |
| 124 | return a->len > b->len ? 1 : -1; |
| 125 | } else |
| 126 | return memcmp(a->blob, b->blob, a->len); |
| 127 | } |
| 128 | |
| 129 | struct ssh_krl * |
| 130 | ssh_krl_init(void) |
| 131 | { |
| 132 | struct ssh_krl *krl; |
| 133 | |
| 134 | if ((krl = calloc(1, sizeof(*krl))) == NULL) |
| 135 | return NULL; |
| 136 | RB_INIT(&krl->revoked_keys); |
| 137 | RB_INIT(&krl->revoked_sha1s); |
| 138 | TAILQ_INIT(&krl->revoked_certs); |
| 139 | return krl; |
| 140 | } |
| 141 | |
| 142 | static void |
| 143 | revoked_certs_free(struct revoked_certs *rc) |
| 144 | { |
| 145 | struct revoked_serial *rs, *trs; |
| 146 | struct revoked_key_id *rki, *trki; |
| 147 | |
| 148 | RB_FOREACH_SAFE(rs, revoked_serial_tree, &rc->revoked_serials, trs) { |
| 149 | RB_REMOVE(revoked_serial_tree, &rc->revoked_serials, rs); |
| 150 | free(rs); |
| 151 | } |
| 152 | RB_FOREACH_SAFE(rki, revoked_key_id_tree, &rc->revoked_key_ids, trki) { |
| 153 | RB_REMOVE(revoked_key_id_tree, &rc->revoked_key_ids, rki); |
| 154 | free(rki->key_id); |
| 155 | free(rki); |
| 156 | } |
| 157 | if (rc->ca_key != NULL) |
| 158 | key_free(rc->ca_key); |
| 159 | } |
| 160 | |
| 161 | void |
| 162 | ssh_krl_free(struct ssh_krl *krl) |
| 163 | { |
| 164 | struct revoked_blob *rb, *trb; |
| 165 | struct revoked_certs *rc, *trc; |
| 166 | |
| 167 | if (krl == NULL) |
| 168 | return; |
| 169 | |
| 170 | free(krl->comment); |
| 171 | RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_keys, trb) { |
| 172 | RB_REMOVE(revoked_blob_tree, &krl->revoked_keys, rb); |
| 173 | free(rb->blob); |
| 174 | free(rb); |
| 175 | } |
| 176 | RB_FOREACH_SAFE(rb, revoked_blob_tree, &krl->revoked_sha1s, trb) { |
| 177 | RB_REMOVE(revoked_blob_tree, &krl->revoked_sha1s, rb); |
| 178 | free(rb->blob); |
| 179 | free(rb); |
| 180 | } |
| 181 | TAILQ_FOREACH_SAFE(rc, &krl->revoked_certs, entry, trc) { |
| 182 | TAILQ_REMOVE(&krl->revoked_certs, rc, entry); |
| 183 | revoked_certs_free(rc); |
| 184 | } |
| 185 | } |
| 186 | |
| 187 | void |
| 188 | ssh_krl_set_version(struct ssh_krl *krl, u_int64_t version) |
| 189 | { |
| 190 | krl->krl_version = version; |
| 191 | } |
| 192 | |
| 193 | void |
| 194 | ssh_krl_set_comment(struct ssh_krl *krl, const char *comment) |
| 195 | { |
| 196 | free(krl->comment); |
| 197 | if ((krl->comment = strdup(comment)) == NULL) |
| 198 | fatal("%s: strdup", __func__); |
| 199 | } |
| 200 | |
| 201 | /* |
| 202 | * Find the revoked_certs struct for a CA key. If allow_create is set then |
| 203 | * create a new one in the tree if one did not exist already. |
| 204 | */ |
| 205 | static int |
| 206 | revoked_certs_for_ca_key(struct ssh_krl *krl, const Key *ca_key, |
| 207 | struct revoked_certs **rcp, int allow_create) |
| 208 | { |
| 209 | struct revoked_certs *rc; |
| 210 | |
| 211 | *rcp = NULL; |
| 212 | TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { |
| 213 | if (key_equal(rc->ca_key, ca_key)) { |
| 214 | *rcp = rc; |
| 215 | return 0; |
| 216 | } |
| 217 | } |
| 218 | if (!allow_create) |
| 219 | return 0; |
| 220 | /* If this CA doesn't exist in the list then add it now */ |
| 221 | if ((rc = calloc(1, sizeof(*rc))) == NULL) |
| 222 | return -1; |
| 223 | if ((rc->ca_key = key_from_private(ca_key)) == NULL) { |
| 224 | free(rc); |
| 225 | return -1; |
| 226 | } |
| 227 | RB_INIT(&rc->revoked_serials); |
| 228 | RB_INIT(&rc->revoked_key_ids); |
| 229 | TAILQ_INSERT_TAIL(&krl->revoked_certs, rc, entry); |
| 230 | debug3("%s: new CA %s", __func__, key_type(ca_key)); |
| 231 | *rcp = rc; |
| 232 | return 0; |
| 233 | } |
| 234 | |
| 235 | static int |
| 236 | insert_serial_range(struct revoked_serial_tree *rt, u_int64_t lo, u_int64_t hi) |
| 237 | { |
| 238 | struct revoked_serial rs, *ers, *crs, *irs; |
| 239 | |
| 240 | KRL_DBG(("%s: insert %llu:%llu", __func__, lo, hi)); |
| 241 | bzero(&rs, sizeof(rs)); |
| 242 | rs.lo = lo; |
| 243 | rs.hi = hi; |
| 244 | ers = RB_NFIND(revoked_serial_tree, rt, &rs); |
| 245 | if (ers == NULL || serial_cmp(ers, &rs) != 0) { |
| 246 | /* No entry matches. Just insert */ |
| 247 | if ((irs = malloc(sizeof(rs))) == NULL) |
| 248 | return -1; |
| 249 | memcpy(irs, &rs, sizeof(*irs)); |
| 250 | ers = RB_INSERT(revoked_serial_tree, rt, irs); |
| 251 | if (ers != NULL) { |
| 252 | KRL_DBG(("%s: bad: ers != NULL", __func__)); |
| 253 | /* Shouldn't happen */ |
Damien Miller | a7522d9 | 2013-01-20 22:35:31 +1100 | [diff] [blame] | 254 | free(irs); |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 255 | return -1; |
| 256 | } |
| 257 | ers = irs; |
| 258 | } else { |
| 259 | KRL_DBG(("%s: overlap found %llu:%llu", __func__, |
| 260 | ers->lo, ers->hi)); |
| 261 | /* |
| 262 | * The inserted entry overlaps an existing one. Grow the |
| 263 | * existing entry. |
| 264 | */ |
| 265 | if (ers->lo > lo) |
| 266 | ers->lo = lo; |
| 267 | if (ers->hi < hi) |
| 268 | ers->hi = hi; |
| 269 | } |
| 270 | /* |
| 271 | * The inserted or revised range might overlap or abut adjacent ones; |
| 272 | * coalesce as necessary. |
| 273 | */ |
| 274 | |
| 275 | /* Check predecessors */ |
| 276 | while ((crs = RB_PREV(revoked_serial_tree, rt, ers)) != NULL) { |
| 277 | KRL_DBG(("%s: pred %llu:%llu", __func__, crs->lo, crs->hi)); |
| 278 | if (ers->lo != 0 && crs->hi < ers->lo - 1) |
| 279 | break; |
| 280 | /* This entry overlaps. */ |
| 281 | if (crs->lo < ers->lo) { |
| 282 | ers->lo = crs->lo; |
| 283 | KRL_DBG(("%s: pred extend %llu:%llu", __func__, |
| 284 | ers->lo, ers->hi)); |
| 285 | } |
| 286 | RB_REMOVE(revoked_serial_tree, rt, crs); |
| 287 | free(crs); |
| 288 | } |
| 289 | /* Check successors */ |
| 290 | while ((crs = RB_NEXT(revoked_serial_tree, rt, ers)) != NULL) { |
| 291 | KRL_DBG(("%s: succ %llu:%llu", __func__, crs->lo, crs->hi)); |
| 292 | if (ers->hi != (u_int64_t)-1 && crs->lo > ers->hi + 1) |
| 293 | break; |
| 294 | /* This entry overlaps. */ |
| 295 | if (crs->hi > ers->hi) { |
| 296 | ers->hi = crs->hi; |
| 297 | KRL_DBG(("%s: succ extend %llu:%llu", __func__, |
| 298 | ers->lo, ers->hi)); |
| 299 | } |
| 300 | RB_REMOVE(revoked_serial_tree, rt, crs); |
| 301 | free(crs); |
| 302 | } |
| 303 | KRL_DBG(("%s: done, final %llu:%llu", __func__, ers->lo, ers->hi)); |
| 304 | return 0; |
| 305 | } |
| 306 | |
| 307 | int |
| 308 | ssh_krl_revoke_cert_by_serial(struct ssh_krl *krl, const Key *ca_key, |
| 309 | u_int64_t serial) |
| 310 | { |
| 311 | return ssh_krl_revoke_cert_by_serial_range(krl, ca_key, serial, serial); |
| 312 | } |
| 313 | |
| 314 | int |
| 315 | ssh_krl_revoke_cert_by_serial_range(struct ssh_krl *krl, const Key *ca_key, |
| 316 | u_int64_t lo, u_int64_t hi) |
| 317 | { |
| 318 | struct revoked_certs *rc; |
| 319 | |
| 320 | if (lo > hi || lo == 0) |
| 321 | return -1; |
| 322 | if (revoked_certs_for_ca_key(krl, ca_key, &rc, 1) != 0) |
| 323 | return -1; |
| 324 | return insert_serial_range(&rc->revoked_serials, lo, hi); |
| 325 | } |
| 326 | |
| 327 | int |
| 328 | ssh_krl_revoke_cert_by_key_id(struct ssh_krl *krl, const Key *ca_key, |
| 329 | const char *key_id) |
| 330 | { |
| 331 | struct revoked_key_id *rki, *erki; |
| 332 | struct revoked_certs *rc; |
| 333 | |
| 334 | if (revoked_certs_for_ca_key(krl, ca_key, &rc, 1) != 0) |
| 335 | return -1; |
| 336 | |
| 337 | debug3("%s: revoke %s", __func__, key_id); |
| 338 | if ((rki = calloc(1, sizeof(*rki))) == NULL || |
| 339 | (rki->key_id = strdup(key_id)) == NULL) { |
| 340 | free(rki); |
| 341 | fatal("%s: strdup", __func__); |
| 342 | } |
| 343 | erki = RB_INSERT(revoked_key_id_tree, &rc->revoked_key_ids, rki); |
| 344 | if (erki != NULL) { |
| 345 | free(rki->key_id); |
| 346 | free(rki); |
| 347 | } |
| 348 | return 0; |
| 349 | } |
| 350 | |
| 351 | /* Convert "key" to a public key blob without any certificate information */ |
| 352 | static int |
| 353 | plain_key_blob(const Key *key, u_char **blob, u_int *blen) |
| 354 | { |
| 355 | Key *kcopy; |
| 356 | int r; |
| 357 | |
| 358 | if ((kcopy = key_from_private(key)) == NULL) |
| 359 | return -1; |
| 360 | if (key_is_cert(kcopy)) { |
| 361 | if (key_drop_cert(kcopy) != 0) { |
| 362 | error("%s: key_drop_cert", __func__); |
| 363 | key_free(kcopy); |
| 364 | return -1; |
| 365 | } |
| 366 | } |
| 367 | r = key_to_blob(kcopy, blob, blen); |
| 368 | free(kcopy); |
| 369 | return r == 0 ? -1 : 0; |
| 370 | } |
| 371 | |
| 372 | /* Revoke a key blob. Ownership of blob is transferred to the tree */ |
| 373 | static int |
| 374 | revoke_blob(struct revoked_blob_tree *rbt, u_char *blob, u_int len) |
| 375 | { |
| 376 | struct revoked_blob *rb, *erb; |
| 377 | |
| 378 | if ((rb = calloc(1, sizeof(*rb))) == NULL) |
| 379 | return -1; |
| 380 | rb->blob = blob; |
| 381 | rb->len = len; |
| 382 | erb = RB_INSERT(revoked_blob_tree, rbt, rb); |
| 383 | if (erb != NULL) { |
| 384 | free(rb->blob); |
| 385 | free(rb); |
| 386 | } |
| 387 | return 0; |
| 388 | } |
| 389 | |
| 390 | int |
| 391 | ssh_krl_revoke_key_explicit(struct ssh_krl *krl, const Key *key) |
| 392 | { |
| 393 | u_char *blob; |
| 394 | u_int len; |
| 395 | |
| 396 | debug3("%s: revoke type %s", __func__, key_type(key)); |
| 397 | if (plain_key_blob(key, &blob, &len) != 0) |
| 398 | return -1; |
| 399 | return revoke_blob(&krl->revoked_keys, blob, len); |
| 400 | } |
| 401 | |
| 402 | int |
| 403 | ssh_krl_revoke_key_sha1(struct ssh_krl *krl, const Key *key) |
| 404 | { |
| 405 | u_char *blob; |
| 406 | u_int len; |
| 407 | |
| 408 | debug3("%s: revoke type %s by sha1", __func__, key_type(key)); |
| 409 | if ((blob = key_fingerprint_raw(key, SSH_FP_SHA1, &len)) == NULL) |
| 410 | return -1; |
| 411 | return revoke_blob(&krl->revoked_sha1s, blob, len); |
| 412 | } |
| 413 | |
| 414 | int |
| 415 | ssh_krl_revoke_key(struct ssh_krl *krl, const Key *key) |
| 416 | { |
| 417 | if (!key_is_cert(key)) |
| 418 | return ssh_krl_revoke_key_sha1(krl, key); |
| 419 | |
| 420 | if (key_cert_is_legacy(key) || key->cert->serial == 0) { |
| 421 | return ssh_krl_revoke_cert_by_key_id(krl, |
| 422 | key->cert->signature_key, |
| 423 | key->cert->key_id); |
| 424 | } else { |
| 425 | return ssh_krl_revoke_cert_by_serial(krl, |
| 426 | key->cert->signature_key, |
| 427 | key->cert->serial); |
| 428 | } |
| 429 | } |
| 430 | |
| 431 | /* |
| 432 | * Select a copact next section type to emit in a KRL based on the |
| 433 | * current section type, the run length of contiguous revoked serial |
| 434 | * numbers and the gaps from the last and to the next revoked serial. |
| 435 | * Applies a mostly-accurate bit cost model to select the section type |
| 436 | * that will minimise the size of the resultant KRL. |
| 437 | */ |
| 438 | static int |
| 439 | choose_next_state(int current_state, u_int64_t contig, int final, |
| 440 | u_int64_t last_gap, u_int64_t next_gap, int *force_new_section) |
| 441 | { |
| 442 | int new_state; |
| 443 | u_int64_t cost, cost_list, cost_range, cost_bitmap, cost_bitmap_restart; |
| 444 | |
| 445 | /* |
| 446 | * Avoid unsigned overflows. |
| 447 | * The limits are high enough to avoid confusing the calculations. |
| 448 | */ |
| 449 | contig = MIN(contig, 1ULL<<31); |
| 450 | last_gap = MIN(last_gap, 1ULL<<31); |
| 451 | next_gap = MIN(next_gap, 1ULL<<31); |
| 452 | |
| 453 | /* |
| 454 | * Calculate the cost to switch from the current state to candidates. |
| 455 | * NB. range sections only ever contain a single range, so their |
| 456 | * switching cost is independent of the current_state. |
| 457 | */ |
| 458 | cost_list = cost_bitmap = cost_bitmap_restart = 0; |
| 459 | cost_range = 8; |
| 460 | switch (current_state) { |
| 461 | case KRL_SECTION_CERT_SERIAL_LIST: |
| 462 | cost_bitmap_restart = cost_bitmap = 8 + 64; |
| 463 | break; |
| 464 | case KRL_SECTION_CERT_SERIAL_BITMAP: |
| 465 | cost_list = 8; |
| 466 | cost_bitmap_restart = 8 + 64; |
| 467 | break; |
| 468 | case KRL_SECTION_CERT_SERIAL_RANGE: |
| 469 | case 0: |
| 470 | cost_bitmap_restart = cost_bitmap = 8 + 64; |
| 471 | cost_list = 8; |
| 472 | } |
| 473 | |
| 474 | /* Estimate base cost in bits of each section type */ |
| 475 | cost_list += 64 * contig + (final ? 0 : 8+64); |
| 476 | cost_range += (2 * 64) + (final ? 0 : 8+64); |
| 477 | cost_bitmap += last_gap + contig + (final ? 0 : MIN(next_gap, 8+64)); |
| 478 | cost_bitmap_restart += contig + (final ? 0 : MIN(next_gap, 8+64)); |
| 479 | |
| 480 | /* Convert to byte costs for actual comparison */ |
| 481 | cost_list = (cost_list + 7) / 8; |
| 482 | cost_bitmap = (cost_bitmap + 7) / 8; |
| 483 | cost_bitmap_restart = (cost_bitmap_restart + 7) / 8; |
| 484 | cost_range = (cost_range + 7) / 8; |
| 485 | |
| 486 | /* Now pick the best choice */ |
| 487 | *force_new_section = 0; |
| 488 | new_state = KRL_SECTION_CERT_SERIAL_BITMAP; |
| 489 | cost = cost_bitmap; |
| 490 | if (cost_range < cost) { |
| 491 | new_state = KRL_SECTION_CERT_SERIAL_RANGE; |
| 492 | cost = cost_range; |
| 493 | } |
| 494 | if (cost_list < cost) { |
| 495 | new_state = KRL_SECTION_CERT_SERIAL_LIST; |
| 496 | cost = cost_list; |
| 497 | } |
| 498 | if (cost_bitmap_restart < cost) { |
| 499 | new_state = KRL_SECTION_CERT_SERIAL_BITMAP; |
| 500 | *force_new_section = 1; |
| 501 | cost = cost_bitmap_restart; |
| 502 | } |
| 503 | debug3("%s: contig %llu last_gap %llu next_gap %llu final %d, costs:" |
| 504 | "list %llu range %llu bitmap %llu new bitmap %llu, " |
| 505 | "selected 0x%02x%s", __func__, contig, last_gap, next_gap, final, |
| 506 | cost_list, cost_range, cost_bitmap, cost_bitmap_restart, new_state, |
| 507 | *force_new_section ? " restart" : ""); |
| 508 | return new_state; |
| 509 | } |
| 510 | |
| 511 | /* Generate a KRL_SECTION_CERTIFICATES KRL section */ |
| 512 | static int |
| 513 | revoked_certs_generate(struct revoked_certs *rc, Buffer *buf) |
| 514 | { |
| 515 | int final, force_new_sect, r = -1; |
| 516 | u_int64_t i, contig, gap, last = 0, bitmap_start = 0; |
| 517 | struct revoked_serial *rs, *nrs; |
| 518 | struct revoked_key_id *rki; |
| 519 | int next_state, state = 0; |
| 520 | Buffer sect; |
| 521 | u_char *kblob = NULL; |
| 522 | u_int klen; |
| 523 | BIGNUM *bitmap = NULL; |
| 524 | |
| 525 | /* Prepare CA scope key blob if we have one supplied */ |
| 526 | if (key_to_blob(rc->ca_key, &kblob, &klen) == 0) |
| 527 | return -1; |
| 528 | |
| 529 | buffer_init(§); |
| 530 | |
| 531 | /* Store the header */ |
| 532 | buffer_put_string(buf, kblob, klen); |
| 533 | buffer_put_string(buf, NULL, 0); /* Reserved */ |
| 534 | |
| 535 | free(kblob); |
| 536 | |
| 537 | /* Store the revoked serials. */ |
| 538 | for (rs = RB_MIN(revoked_serial_tree, &rc->revoked_serials); |
| 539 | rs != NULL; |
| 540 | rs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs)) { |
| 541 | debug3("%s: serial %llu:%llu state 0x%02x", __func__, |
| 542 | rs->lo, rs->hi, state); |
| 543 | |
| 544 | /* Check contiguous length and gap to next section (if any) */ |
| 545 | nrs = RB_NEXT(revoked_serial_tree, &rc->revoked_serials, rs); |
| 546 | final = nrs == NULL; |
| 547 | gap = nrs == NULL ? 0 : nrs->lo - rs->hi; |
| 548 | contig = 1 + (rs->hi - rs->lo); |
| 549 | |
| 550 | /* Choose next state based on these */ |
| 551 | next_state = choose_next_state(state, contig, final, |
| 552 | state == 0 ? 0 : rs->lo - last, gap, &force_new_sect); |
| 553 | |
| 554 | /* |
| 555 | * If the current section is a range section or has a different |
| 556 | * type to the next section, then finish it off now. |
| 557 | */ |
| 558 | if (state != 0 && (force_new_sect || next_state != state || |
| 559 | state == KRL_SECTION_CERT_SERIAL_RANGE)) { |
| 560 | debug3("%s: finish state 0x%02x", __func__, state); |
| 561 | switch (state) { |
| 562 | case KRL_SECTION_CERT_SERIAL_LIST: |
| 563 | case KRL_SECTION_CERT_SERIAL_RANGE: |
| 564 | break; |
| 565 | case KRL_SECTION_CERT_SERIAL_BITMAP: |
| 566 | buffer_put_bignum2(§, bitmap); |
| 567 | BN_free(bitmap); |
| 568 | bitmap = NULL; |
| 569 | break; |
| 570 | } |
| 571 | buffer_put_char(buf, state); |
| 572 | buffer_put_string(buf, |
| 573 | buffer_ptr(§), buffer_len(§)); |
| 574 | } |
| 575 | |
| 576 | /* If we are starting a new section then prepare it now */ |
| 577 | if (next_state != state || force_new_sect) { |
| 578 | debug3("%s: start state 0x%02x", __func__, next_state); |
| 579 | state = next_state; |
| 580 | buffer_clear(§); |
| 581 | switch (state) { |
| 582 | case KRL_SECTION_CERT_SERIAL_LIST: |
| 583 | case KRL_SECTION_CERT_SERIAL_RANGE: |
| 584 | break; |
| 585 | case KRL_SECTION_CERT_SERIAL_BITMAP: |
| 586 | if ((bitmap = BN_new()) == NULL) |
| 587 | goto out; |
| 588 | bitmap_start = rs->lo; |
| 589 | buffer_put_int64(§, bitmap_start); |
| 590 | break; |
| 591 | } |
| 592 | } |
| 593 | |
| 594 | /* Perform section-specific processing */ |
| 595 | switch (state) { |
| 596 | case KRL_SECTION_CERT_SERIAL_LIST: |
Damien Miller | 13f5f76 | 2013-01-18 15:32:03 +1100 | [diff] [blame] | 597 | for (i = 0; i < contig; i++) |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 598 | buffer_put_int64(§, rs->lo + i); |
| 599 | break; |
| 600 | case KRL_SECTION_CERT_SERIAL_RANGE: |
| 601 | buffer_put_int64(§, rs->lo); |
| 602 | buffer_put_int64(§, rs->hi); |
| 603 | break; |
| 604 | case KRL_SECTION_CERT_SERIAL_BITMAP: |
| 605 | if (rs->lo - bitmap_start > INT_MAX) { |
| 606 | error("%s: insane bitmap gap", __func__); |
| 607 | goto out; |
| 608 | } |
| 609 | for (i = 0; i < contig; i++) { |
| 610 | if (BN_set_bit(bitmap, |
| 611 | rs->lo + i - bitmap_start) != 1) |
| 612 | goto out; |
| 613 | } |
| 614 | break; |
| 615 | } |
| 616 | last = rs->hi; |
| 617 | } |
| 618 | /* Flush the remaining section, if any */ |
| 619 | if (state != 0) { |
| 620 | debug3("%s: serial final flush for state 0x%02x", |
| 621 | __func__, 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 | buffer_put_bignum2(§, bitmap); |
| 628 | BN_free(bitmap); |
| 629 | bitmap = NULL; |
| 630 | break; |
| 631 | } |
| 632 | buffer_put_char(buf, state); |
| 633 | buffer_put_string(buf, |
| 634 | buffer_ptr(§), buffer_len(§)); |
| 635 | } |
| 636 | debug3("%s: serial done ", __func__); |
| 637 | |
| 638 | /* Now output a section for any revocations by key ID */ |
| 639 | buffer_clear(§); |
| 640 | RB_FOREACH(rki, revoked_key_id_tree, &rc->revoked_key_ids) { |
| 641 | debug3("%s: key ID %s", __func__, rki->key_id); |
| 642 | buffer_put_cstring(§, rki->key_id); |
| 643 | } |
| 644 | if (buffer_len(§) != 0) { |
| 645 | buffer_put_char(buf, KRL_SECTION_CERT_KEY_ID); |
| 646 | buffer_put_string(buf, buffer_ptr(§), |
| 647 | buffer_len(§)); |
| 648 | } |
| 649 | r = 0; |
| 650 | out: |
| 651 | if (bitmap != NULL) |
| 652 | BN_free(bitmap); |
| 653 | buffer_free(§); |
| 654 | return r; |
| 655 | } |
| 656 | |
| 657 | int |
| 658 | ssh_krl_to_blob(struct ssh_krl *krl, Buffer *buf, const Key **sign_keys, |
| 659 | u_int nsign_keys) |
| 660 | { |
| 661 | int r = -1; |
| 662 | struct revoked_certs *rc; |
| 663 | struct revoked_blob *rb; |
| 664 | Buffer sect; |
| 665 | u_char *kblob = NULL, *sblob = NULL; |
| 666 | u_int klen, slen, i; |
| 667 | |
| 668 | if (krl->generated_date == 0) |
| 669 | krl->generated_date = time(NULL); |
| 670 | |
| 671 | buffer_init(§); |
| 672 | |
| 673 | /* Store the header */ |
| 674 | buffer_append(buf, KRL_MAGIC, sizeof(KRL_MAGIC) - 1); |
| 675 | buffer_put_int(buf, KRL_FORMAT_VERSION); |
| 676 | buffer_put_int64(buf, krl->krl_version); |
| 677 | buffer_put_int64(buf, krl->generated_date); |
| 678 | buffer_put_int64(buf, krl->flags); |
| 679 | buffer_put_string(buf, NULL, 0); |
| 680 | buffer_put_cstring(buf, krl->comment ? krl->comment : ""); |
| 681 | |
| 682 | /* Store sections for revoked certificates */ |
| 683 | TAILQ_FOREACH(rc, &krl->revoked_certs, entry) { |
| 684 | if (revoked_certs_generate(rc, §) != 0) |
| 685 | goto out; |
| 686 | buffer_put_char(buf, KRL_SECTION_CERTIFICATES); |
| 687 | buffer_put_string(buf, buffer_ptr(§), |
| 688 | buffer_len(§)); |
| 689 | } |
| 690 | |
| 691 | /* Finally, output sections for revocations by public key/hash */ |
| 692 | buffer_clear(§); |
| 693 | RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_keys) { |
| 694 | debug3("%s: key len %u ", __func__, rb->len); |
| 695 | buffer_put_string(§, rb->blob, rb->len); |
| 696 | } |
| 697 | if (buffer_len(§) != 0) { |
| 698 | buffer_put_char(buf, KRL_SECTION_EXPLICIT_KEY); |
| 699 | buffer_put_string(buf, buffer_ptr(§), |
| 700 | buffer_len(§)); |
| 701 | } |
| 702 | buffer_clear(§); |
| 703 | RB_FOREACH(rb, revoked_blob_tree, &krl->revoked_sha1s) { |
| 704 | debug3("%s: hash len %u ", __func__, rb->len); |
| 705 | buffer_put_string(§, rb->blob, rb->len); |
| 706 | } |
| 707 | if (buffer_len(§) != 0) { |
| 708 | buffer_put_char(buf, KRL_SECTION_FINGERPRINT_SHA1); |
| 709 | buffer_put_string(buf, buffer_ptr(§), |
| 710 | buffer_len(§)); |
| 711 | } |
| 712 | |
| 713 | for (i = 0; i < nsign_keys; i++) { |
| 714 | if (key_to_blob(sign_keys[i], &kblob, &klen) == 0) |
| 715 | goto out; |
| 716 | |
| 717 | debug3("%s: signature key len %u", __func__, klen); |
| 718 | buffer_put_char(buf, KRL_SECTION_SIGNATURE); |
| 719 | buffer_put_string(buf, kblob, klen); |
| 720 | |
| 721 | if (key_sign(sign_keys[i], &sblob, &slen, |
| 722 | buffer_ptr(buf), buffer_len(buf)) == -1) |
| 723 | goto out; |
| 724 | debug3("%s: signature sig len %u", __func__, slen); |
| 725 | buffer_put_string(buf, sblob, slen); |
| 726 | } |
| 727 | |
| 728 | r = 0; |
| 729 | out: |
| 730 | free(kblob); |
| 731 | free(sblob); |
| 732 | buffer_free(§); |
| 733 | return r; |
| 734 | } |
| 735 | |
| 736 | static void |
| 737 | format_timestamp(u_int64_t timestamp, char *ts, size_t nts) |
| 738 | { |
| 739 | time_t t; |
| 740 | struct tm *tm; |
| 741 | |
| 742 | t = timestamp; |
| 743 | tm = localtime(&t); |
| 744 | *ts = '\0'; |
| 745 | strftime(ts, nts, "%Y%m%dT%H%M%S", tm); |
| 746 | } |
| 747 | |
| 748 | static int |
| 749 | parse_revoked_certs(Buffer *buf, struct ssh_krl *krl) |
| 750 | { |
| 751 | int ret = -1, nbits; |
| 752 | u_char type, *blob; |
| 753 | u_int blen; |
| 754 | Buffer subsect; |
| 755 | u_int64_t serial, serial_lo, serial_hi; |
| 756 | BIGNUM *bitmap = NULL; |
| 757 | char *key_id = NULL; |
| 758 | Key *ca_key = NULL; |
| 759 | |
| 760 | buffer_init(&subsect); |
| 761 | |
| 762 | if ((blob = buffer_get_string_ptr_ret(buf, &blen)) == NULL || |
| 763 | buffer_get_string_ptr_ret(buf, NULL) == NULL) { /* reserved */ |
| 764 | error("%s: buffer error", __func__); |
| 765 | goto out; |
| 766 | } |
| 767 | if ((ca_key = key_from_blob(blob, blen)) == NULL) |
| 768 | goto out; |
| 769 | |
| 770 | while (buffer_len(buf) > 0) { |
| 771 | if (buffer_get_char_ret(&type, buf) != 0 || |
| 772 | (blob = buffer_get_string_ptr_ret(buf, &blen)) == NULL) { |
| 773 | error("%s: buffer error", __func__); |
| 774 | goto out; |
| 775 | } |
| 776 | buffer_clear(&subsect); |
| 777 | buffer_append(&subsect, blob, blen); |
| 778 | debug3("%s: subsection type 0x%02x", __func__, type); |
| 779 | /* buffer_dump(&subsect); */ |
| 780 | |
| 781 | switch (type) { |
| 782 | case KRL_SECTION_CERT_SERIAL_LIST: |
| 783 | while (buffer_len(&subsect) > 0) { |
| 784 | if (buffer_get_int64_ret(&serial, |
| 785 | &subsect) != 0) { |
| 786 | error("%s: buffer error", __func__); |
| 787 | goto out; |
| 788 | } |
| 789 | if (ssh_krl_revoke_cert_by_serial(krl, ca_key, |
| 790 | serial) != 0) { |
| 791 | error("%s: update failed", __func__); |
| 792 | goto out; |
| 793 | } |
| 794 | } |
| 795 | break; |
| 796 | case KRL_SECTION_CERT_SERIAL_RANGE: |
| 797 | if (buffer_get_int64_ret(&serial_lo, &subsect) != 0 || |
| 798 | buffer_get_int64_ret(&serial_hi, &subsect) != 0) { |
| 799 | error("%s: buffer error", __func__); |
| 800 | goto out; |
| 801 | } |
| 802 | if (ssh_krl_revoke_cert_by_serial_range(krl, ca_key, |
| 803 | serial_lo, serial_hi) != 0) { |
| 804 | error("%s: update failed", __func__); |
| 805 | goto out; |
| 806 | } |
| 807 | break; |
| 808 | case KRL_SECTION_CERT_SERIAL_BITMAP: |
| 809 | if ((bitmap = BN_new()) == NULL) { |
| 810 | error("%s: BN_new", __func__); |
| 811 | goto out; |
| 812 | } |
| 813 | if (buffer_get_int64_ret(&serial_lo, &subsect) != 0 || |
| 814 | buffer_get_bignum2_ret(&subsect, bitmap) != 0) { |
| 815 | error("%s: buffer error", __func__); |
| 816 | goto out; |
| 817 | } |
| 818 | if ((nbits = BN_num_bits(bitmap)) < 0) { |
| 819 | error("%s: bitmap bits < 0", __func__); |
| 820 | goto out; |
| 821 | } |
| 822 | for (serial = 0; serial < (u_int)nbits; serial++) { |
| 823 | if (serial > 0 && serial_lo + serial == 0) { |
| 824 | error("%s: bitmap wraps u64", __func__); |
| 825 | goto out; |
| 826 | } |
| 827 | if (!BN_is_bit_set(bitmap, serial)) |
| 828 | continue; |
| 829 | if (ssh_krl_revoke_cert_by_serial(krl, ca_key, |
| 830 | serial_lo + serial) != 0) { |
| 831 | error("%s: update failed", __func__); |
| 832 | goto out; |
| 833 | } |
| 834 | } |
| 835 | BN_free(bitmap); |
| 836 | bitmap = NULL; |
| 837 | break; |
| 838 | case KRL_SECTION_CERT_KEY_ID: |
| 839 | while (buffer_len(&subsect) > 0) { |
| 840 | if ((key_id = buffer_get_cstring_ret(&subsect, |
| 841 | NULL)) == NULL) { |
| 842 | error("%s: buffer error", __func__); |
| 843 | goto out; |
| 844 | } |
| 845 | if (ssh_krl_revoke_cert_by_key_id(krl, ca_key, |
| 846 | key_id) != 0) { |
| 847 | error("%s: update failed", __func__); |
| 848 | goto out; |
| 849 | } |
| 850 | free(key_id); |
| 851 | key_id = NULL; |
| 852 | } |
| 853 | break; |
| 854 | default: |
| 855 | error("Unsupported KRL certificate section %u", type); |
| 856 | goto out; |
| 857 | } |
| 858 | if (buffer_len(&subsect) > 0) { |
| 859 | error("KRL certificate section contains unparsed data"); |
| 860 | goto out; |
| 861 | } |
| 862 | } |
| 863 | |
| 864 | ret = 0; |
| 865 | out: |
| 866 | if (ca_key != NULL) |
| 867 | key_free(ca_key); |
| 868 | if (bitmap != NULL) |
| 869 | BN_free(bitmap); |
| 870 | free(key_id); |
| 871 | buffer_free(&subsect); |
| 872 | return ret; |
| 873 | } |
| 874 | |
| 875 | |
| 876 | /* Attempt to parse a KRL, checking its signature (if any) with sign_ca_keys. */ |
| 877 | int |
| 878 | ssh_krl_from_blob(Buffer *buf, struct ssh_krl **krlp, |
| 879 | const Key **sign_ca_keys, u_int nsign_ca_keys) |
| 880 | { |
| 881 | Buffer copy, sect; |
| 882 | struct ssh_krl *krl; |
| 883 | char timestamp[64]; |
| 884 | int ret = -1, r, sig_seen; |
| 885 | Key *key = NULL, **ca_used = NULL; |
| 886 | u_char type, *blob; |
| 887 | u_int i, j, sig_off, sects_off, blen, format_version, nca_used = 0; |
| 888 | |
| 889 | *krlp = NULL; |
| 890 | if (buffer_len(buf) < sizeof(KRL_MAGIC) - 1 || |
| 891 | memcmp(buffer_ptr(buf), KRL_MAGIC, sizeof(KRL_MAGIC) - 1) != 0) { |
| 892 | debug3("%s: not a KRL", __func__); |
| 893 | /* |
| 894 | * Return success but a NULL *krlp here to signal that the |
| 895 | * file might be a simple list of keys. |
| 896 | */ |
| 897 | return 0; |
| 898 | } |
| 899 | |
| 900 | /* Take a copy of the KRL buffer so we can verify its signature later */ |
| 901 | buffer_init(©); |
| 902 | buffer_append(©, buffer_ptr(buf), buffer_len(buf)); |
| 903 | |
| 904 | buffer_init(§); |
| 905 | buffer_consume(©, sizeof(KRL_MAGIC) - 1); |
| 906 | |
| 907 | if ((krl = ssh_krl_init()) == NULL) { |
| 908 | error("%s: alloc failed", __func__); |
| 909 | goto out; |
| 910 | } |
| 911 | |
| 912 | if (buffer_get_int_ret(&format_version, ©) != 0) { |
| 913 | error("%s: KRL truncated", __func__); |
| 914 | goto out; |
| 915 | } |
| 916 | if (format_version != KRL_FORMAT_VERSION) { |
| 917 | error("%s: KRL unsupported format version %u", |
| 918 | __func__, format_version); |
| 919 | goto out; |
| 920 | } |
| 921 | if (buffer_get_int64_ret(&krl->krl_version, ©) != 0 || |
| 922 | buffer_get_int64_ret(&krl->generated_date, ©) != 0 || |
| 923 | buffer_get_int64_ret(&krl->flags, ©) != 0 || |
| 924 | buffer_get_string_ptr_ret(©, NULL) == NULL || /* reserved */ |
| 925 | (krl->comment = buffer_get_cstring_ret(©, NULL)) == NULL) { |
| 926 | error("%s: buffer error", __func__); |
| 927 | goto out; |
| 928 | } |
| 929 | |
| 930 | format_timestamp(krl->generated_date, timestamp, sizeof(timestamp)); |
| 931 | debug("KRL version %llu generated at %s%s%s", krl->krl_version, |
| 932 | timestamp, *krl->comment ? ": " : "", krl->comment); |
| 933 | |
| 934 | /* |
| 935 | * 1st pass: verify signatures, if any. This is done to avoid |
| 936 | * detailed parsing of data whose provenance is unverified. |
| 937 | */ |
| 938 | sig_seen = 0; |
| 939 | sects_off = buffer_len(buf) - buffer_len(©); |
| 940 | while (buffer_len(©) > 0) { |
| 941 | if (buffer_get_char_ret(&type, ©) != 0 || |
| 942 | (blob = buffer_get_string_ptr_ret(©, &blen)) == NULL) { |
| 943 | error("%s: buffer error", __func__); |
| 944 | goto out; |
| 945 | } |
| 946 | debug3("%s: first pass, section 0x%02x", __func__, type); |
| 947 | if (type != KRL_SECTION_SIGNATURE) { |
| 948 | if (sig_seen) { |
| 949 | error("KRL contains non-signature section " |
| 950 | "after signature"); |
| 951 | goto out; |
| 952 | } |
| 953 | /* Not interested for now. */ |
| 954 | continue; |
| 955 | } |
| 956 | sig_seen = 1; |
| 957 | /* First string component is the signing key */ |
| 958 | if ((key = key_from_blob(blob, blen)) == NULL) { |
| 959 | error("%s: invalid signature key", __func__); |
| 960 | goto out; |
| 961 | } |
| 962 | sig_off = buffer_len(buf) - buffer_len(©); |
| 963 | /* Second string component is the signature itself */ |
| 964 | if ((blob = buffer_get_string_ptr_ret(©, &blen)) == NULL) { |
| 965 | error("%s: buffer error", __func__); |
| 966 | goto out; |
| 967 | } |
| 968 | /* Check signature over entire KRL up to this point */ |
| 969 | if (key_verify(key, blob, blen, |
| 970 | buffer_ptr(buf), buffer_len(buf) - sig_off) == -1) { |
| 971 | error("bad signaure on KRL"); |
| 972 | goto out; |
| 973 | } |
| 974 | /* Check if this key has already signed this KRL */ |
| 975 | for (i = 0; i < nca_used; i++) { |
| 976 | if (key_equal(ca_used[i], key)) { |
| 977 | error("KRL signed more than once with " |
| 978 | "the same key"); |
| 979 | goto out; |
| 980 | } |
| 981 | } |
| 982 | /* Record keys used to sign the KRL */ |
Damien Miller | 0cd2f8e | 2013-02-12 11:01:39 +1100 | [diff] [blame] | 983 | ca_used = xrealloc(ca_used, nca_used + 1, sizeof(*ca_used)); |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 984 | ca_used[nca_used++] = key; |
| 985 | key = NULL; |
| 986 | break; |
| 987 | } |
| 988 | |
| 989 | /* |
| 990 | * 2nd pass: parse and load the KRL, skipping the header to the point |
| 991 | * where the section start. |
| 992 | */ |
| 993 | buffer_append(©, (u_char*)buffer_ptr(buf) + sects_off, |
| 994 | buffer_len(buf) - sects_off); |
| 995 | while (buffer_len(©) > 0) { |
| 996 | if (buffer_get_char_ret(&type, ©) != 0 || |
| 997 | (blob = buffer_get_string_ptr_ret(©, &blen)) == NULL) { |
| 998 | error("%s: buffer error", __func__); |
| 999 | goto out; |
| 1000 | } |
| 1001 | debug3("%s: second pass, section 0x%02x", __func__, type); |
| 1002 | buffer_clear(§); |
| 1003 | buffer_append(§, blob, blen); |
| 1004 | |
| 1005 | switch (type) { |
| 1006 | case KRL_SECTION_CERTIFICATES: |
| 1007 | if ((r = parse_revoked_certs(§, krl)) != 0) |
| 1008 | goto out; |
| 1009 | break; |
| 1010 | case KRL_SECTION_EXPLICIT_KEY: |
| 1011 | case KRL_SECTION_FINGERPRINT_SHA1: |
| 1012 | while (buffer_len(§) > 0) { |
| 1013 | if ((blob = buffer_get_string_ret(§, |
| 1014 | &blen)) == NULL) { |
| 1015 | error("%s: buffer error", __func__); |
| 1016 | goto out; |
| 1017 | } |
| 1018 | if (type == KRL_SECTION_FINGERPRINT_SHA1 && |
| 1019 | blen != 20) { |
| 1020 | error("%s: bad SHA1 length", __func__); |
| 1021 | goto out; |
| 1022 | } |
| 1023 | if (revoke_blob( |
| 1024 | type == KRL_SECTION_EXPLICIT_KEY ? |
| 1025 | &krl->revoked_keys : &krl->revoked_sha1s, |
| 1026 | blob, blen) != 0) |
| 1027 | goto out; /* revoke_blob frees blob */ |
| 1028 | } |
| 1029 | break; |
| 1030 | case KRL_SECTION_SIGNATURE: |
| 1031 | /* Handled above, but still need to stay in synch */ |
| 1032 | buffer_clear(§); |
Damien Miller | ea07846 | 2013-02-12 10:54:37 +1100 | [diff] [blame] | 1033 | if ((blob = buffer_get_string_ptr_ret(©, |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 1034 | &blen)) == NULL) { |
| 1035 | error("%s: buffer error", __func__); |
| 1036 | goto out; |
| 1037 | } |
| 1038 | break; |
| 1039 | default: |
| 1040 | error("Unsupported KRL section %u", type); |
| 1041 | goto out; |
| 1042 | } |
| 1043 | if (buffer_len(§) > 0) { |
| 1044 | error("KRL section contains unparsed data"); |
| 1045 | goto out; |
| 1046 | } |
| 1047 | } |
| 1048 | |
| 1049 | /* Check that the key(s) used to sign the KRL weren't revoked */ |
| 1050 | sig_seen = 0; |
| 1051 | for (i = 0; i < nca_used; i++) { |
| 1052 | if (ssh_krl_check_key(krl, ca_used[i]) == 0) |
| 1053 | sig_seen = 1; |
| 1054 | else { |
| 1055 | key_free(ca_used[i]); |
| 1056 | ca_used[i] = NULL; |
| 1057 | } |
| 1058 | } |
| 1059 | if (nca_used && !sig_seen) { |
| 1060 | error("All keys used to sign KRL were revoked"); |
| 1061 | goto out; |
| 1062 | } |
| 1063 | |
| 1064 | /* If we have CA keys, then verify that one was used to sign the KRL */ |
| 1065 | if (sig_seen && nsign_ca_keys != 0) { |
| 1066 | sig_seen = 0; |
| 1067 | for (i = 0; !sig_seen && i < nsign_ca_keys; i++) { |
| 1068 | for (j = 0; j < nca_used; j++) { |
| 1069 | if (ca_used[j] == NULL) |
| 1070 | continue; |
| 1071 | if (key_equal(ca_used[j], sign_ca_keys[i])) { |
| 1072 | sig_seen = 1; |
| 1073 | break; |
| 1074 | } |
| 1075 | } |
| 1076 | } |
| 1077 | if (!sig_seen) { |
| 1078 | error("KRL not signed with any trusted key"); |
| 1079 | goto out; |
| 1080 | } |
| 1081 | } |
| 1082 | |
| 1083 | *krlp = krl; |
| 1084 | ret = 0; |
| 1085 | out: |
| 1086 | if (ret != 0) |
| 1087 | ssh_krl_free(krl); |
| 1088 | for (i = 0; i < nca_used; i++) { |
| 1089 | if (ca_used[i] != NULL) |
| 1090 | key_free(ca_used[i]); |
| 1091 | } |
| 1092 | free(ca_used); |
| 1093 | if (key != NULL) |
| 1094 | key_free(key); |
| 1095 | buffer_free(©); |
| 1096 | buffer_free(§); |
| 1097 | return ret; |
| 1098 | } |
| 1099 | |
| 1100 | /* Checks whether a given key/cert is revoked. Does not check its CA */ |
| 1101 | static int |
| 1102 | is_key_revoked(struct ssh_krl *krl, const Key *key) |
| 1103 | { |
| 1104 | struct revoked_blob rb, *erb; |
| 1105 | struct revoked_serial rs, *ers; |
| 1106 | struct revoked_key_id rki, *erki; |
| 1107 | struct revoked_certs *rc; |
| 1108 | |
| 1109 | /* Check explicitly revoked hashes first */ |
| 1110 | bzero(&rb, sizeof(rb)); |
| 1111 | if ((rb.blob = key_fingerprint_raw(key, SSH_FP_SHA1, &rb.len)) == NULL) |
| 1112 | return -1; |
| 1113 | erb = RB_FIND(revoked_blob_tree, &krl->revoked_sha1s, &rb); |
| 1114 | free(rb.blob); |
| 1115 | if (erb != NULL) { |
| 1116 | debug("%s: revoked by key SHA1", __func__); |
| 1117 | return -1; |
| 1118 | } |
| 1119 | |
| 1120 | /* Next, explicit keys */ |
| 1121 | bzero(&rb, sizeof(rb)); |
| 1122 | if (plain_key_blob(key, &rb.blob, &rb.len) != 0) |
| 1123 | return -1; |
| 1124 | erb = RB_FIND(revoked_blob_tree, &krl->revoked_keys, &rb); |
| 1125 | free(rb.blob); |
| 1126 | if (erb != NULL) { |
| 1127 | debug("%s: revoked by explicit key", __func__); |
| 1128 | return -1; |
| 1129 | } |
| 1130 | |
| 1131 | if (!key_is_cert(key)) |
| 1132 | return 0; |
| 1133 | |
| 1134 | /* Check cert revocation */ |
| 1135 | if (revoked_certs_for_ca_key(krl, key->cert->signature_key, |
| 1136 | &rc, 0) != 0) |
| 1137 | return -1; |
| 1138 | if (rc == NULL) |
| 1139 | return 0; /* No entry for this CA */ |
| 1140 | |
| 1141 | /* Check revocation by cert key ID */ |
| 1142 | bzero(&rki, sizeof(rki)); |
| 1143 | rki.key_id = key->cert->key_id; |
| 1144 | erki = RB_FIND(revoked_key_id_tree, &rc->revoked_key_ids, &rki); |
| 1145 | if (erki != NULL) { |
| 1146 | debug("%s: revoked by key ID", __func__); |
| 1147 | return -1; |
| 1148 | } |
| 1149 | |
Damien Miller | 60565bc | 2013-02-12 10:56:42 +1100 | [diff] [blame] | 1150 | /* |
| 1151 | * Legacy cert formats lack serial numbers. Zero serials numbers |
| 1152 | * are ignored (it's the default when the CA doesn't specify one). |
| 1153 | */ |
| 1154 | if (key_cert_is_legacy(key) || key->cert->serial == 0) |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 1155 | return 0; |
| 1156 | |
| 1157 | bzero(&rs, sizeof(rs)); |
| 1158 | rs.lo = rs.hi = key->cert->serial; |
| 1159 | ers = RB_FIND(revoked_serial_tree, &rc->revoked_serials, &rs); |
| 1160 | if (ers != NULL) { |
| 1161 | KRL_DBG(("%s: %llu matched %llu:%llu", __func__, |
| 1162 | key->cert->serial, ers->lo, ers->hi)); |
| 1163 | debug("%s: revoked by serial", __func__); |
| 1164 | return -1; |
| 1165 | } |
| 1166 | KRL_DBG(("%s: %llu no match", __func__, key->cert->serial)); |
| 1167 | |
| 1168 | return 0; |
| 1169 | } |
| 1170 | |
| 1171 | int |
| 1172 | ssh_krl_check_key(struct ssh_krl *krl, const Key *key) |
| 1173 | { |
| 1174 | int r; |
| 1175 | |
| 1176 | debug2("%s: checking key", __func__); |
| 1177 | if ((r = is_key_revoked(krl, key)) != 0) |
| 1178 | return r; |
| 1179 | if (key_is_cert(key)) { |
| 1180 | debug2("%s: checking CA key", __func__); |
| 1181 | if ((r = is_key_revoked(krl, key->cert->signature_key)) != 0) |
| 1182 | return r; |
| 1183 | } |
| 1184 | debug3("%s: key okay", __func__); |
| 1185 | return 0; |
| 1186 | } |
| 1187 | |
| 1188 | /* Returns 0 on success, -1 on error or key revoked, -2 if path is not a KRL */ |
| 1189 | int |
| 1190 | ssh_krl_file_contains_key(const char *path, const Key *key) |
| 1191 | { |
| 1192 | Buffer krlbuf; |
| 1193 | struct ssh_krl *krl; |
| 1194 | int revoked, fd; |
| 1195 | |
| 1196 | if (path == NULL) |
| 1197 | return 0; |
| 1198 | |
| 1199 | if ((fd = open(path, O_RDONLY)) == -1) { |
| 1200 | error("open %s: %s", path, strerror(errno)); |
| 1201 | error("Revoked keys file not accessible - refusing public key " |
| 1202 | "authentication"); |
| 1203 | return -1; |
| 1204 | } |
| 1205 | buffer_init(&krlbuf); |
| 1206 | if (!key_load_file(fd, path, &krlbuf)) { |
| 1207 | close(fd); |
| 1208 | buffer_free(&krlbuf); |
| 1209 | error("Revoked keys file not readable - refusing public key " |
| 1210 | "authentication"); |
| 1211 | return -1; |
| 1212 | } |
| 1213 | close(fd); |
| 1214 | if (ssh_krl_from_blob(&krlbuf, &krl, NULL, 0) != 0) { |
| 1215 | buffer_free(&krlbuf); |
| 1216 | error("Invalid KRL, refusing public key " |
| 1217 | "authentication"); |
| 1218 | return -1; |
| 1219 | } |
| 1220 | buffer_free(&krlbuf); |
| 1221 | if (krl == NULL) { |
| 1222 | debug3("%s: %s is not a KRL file", __func__, path); |
| 1223 | return -2; |
| 1224 | } |
| 1225 | debug2("%s: checking KRL %s", __func__, path); |
| 1226 | revoked = ssh_krl_check_key(krl, key) != 0; |
| 1227 | ssh_krl_free(krl); |
| 1228 | return revoked ? -1 : 0; |
| 1229 | } |