| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Key loading and storing |
| 4 | * |
| 5 | * (c) 2001 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of Trivial IP Encryption (TrIPE). |
| 11 | * |
| 12 | * TrIPE is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU General Public License as published by |
| 14 | * the Free Software Foundation; either version 2 of the License, or |
| 15 | * (at your option) any later version. |
| 16 | * |
| 17 | * TrIPE is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU General Public License |
| 23 | * along with TrIPE; if not, write to the Free Software Foundation, |
| 24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 25 | */ |
| 26 | |
| 27 | /*----- Header files ------------------------------------------------------*/ |
| 28 | |
| 29 | #include "tripe.h" |
| 30 | |
| 31 | /*----- Key groups --------------------------------------------------------*/ |
| 32 | |
| 33 | /* The key-loading functions here must fill in the kdata slot @g@ and |
| 34 | * either @kpriv@ or @kpub@ as appropriate. The caller will take care of |
| 35 | * determining @kpub@ given a private key, and of ensuring that @kpriv@ is |
| 36 | * null for a public key. |
| 37 | */ |
| 38 | |
| 39 | typedef struct kgops { |
| 40 | const char *ty; |
| 41 | int (*loadpriv)(key_data *, kdata *, dstr *, dstr *); |
| 42 | int (*loadpub)(key_data *, kdata *, dstr *, dstr *); |
| 43 | } kgops; |
| 44 | |
| 45 | /* --- @KLOAD@ --- * |
| 46 | * |
| 47 | * Arguments: @ty@, @TY@ = key type name (lower- and upper-case) |
| 48 | * @which@, @WHICH@ = `pub' or `priv' (and upper-case) |
| 49 | * @setgroup@ = code to initialize @kd->g@ |
| 50 | * @setpriv@ = code to initialize @kd->kpriv@ |
| 51 | * @setpub@ = code to initialize @kd->kpub@ |
| 52 | * |
| 53 | * Use: Generates the body of one of the (rather tedious) key loading |
| 54 | * functions. See the description of @KEYTYPES@ below for the |
| 55 | * details. |
| 56 | */ |
| 57 | |
| 58 | #define KLOAD(ty, TY, which, WHICH, setgroup, setpriv, setpub) \ |
| 59 | static int kg##ty##_##which(key_data *d, kdata *kd, dstr *t, dstr *e) \ |
| 60 | { \ |
| 61 | key_packstruct kps[TY##_##WHICH##FETCHSZ]; \ |
| 62 | key_packdef *kp; \ |
| 63 | ty##_##which p; \ |
| 64 | int rc; \ |
| 65 | \ |
| 66 | /* --- Initialize things we've not set up yet --- */ \ |
| 67 | \ |
| 68 | kd->g = 0; kd->kpub = 0; \ |
| 69 | \ |
| 70 | /* --- Unpack the key --- */ \ |
| 71 | \ |
| 72 | kp = key_fetchinit(ty##_##which##fetch, kps, &p); \ |
| 73 | if ((rc = key_unpack(kp, d, t)) != 0) { \ |
| 74 | a_format(e, "unpack-failed", "%s", key_strerror(rc), A_END); \ |
| 75 | goto fail; \ |
| 76 | } \ |
| 77 | \ |
| 78 | /* --- Extract the pieces of the key --- */ \ |
| 79 | \ |
| 80 | setgroup; \ |
| 81 | setpriv; \ |
| 82 | kd->kpub = G_CREATE(kd->g); \ |
| 83 | setpub; \ |
| 84 | \ |
| 85 | /* --- We win --- */ \ |
| 86 | \ |
| 87 | rc = 0; \ |
| 88 | goto done; \ |
| 89 | \ |
| 90 | fail: \ |
| 91 | if (kd->kpub) G_DESTROY(kd->g, kd->kpub); \ |
| 92 | if (kd->g) G_DESTROYGROUP(kd->g); \ |
| 93 | rc = -1; \ |
| 94 | \ |
| 95 | done: \ |
| 96 | key_fetchdone(kp); \ |
| 97 | return (rc); \ |
| 98 | } |
| 99 | |
| 100 | /* --- @KEYTYPES@ --- * |
| 101 | * |
| 102 | * A list of the various key types, and how to unpack them. Each entry in |
| 103 | * the list has the form |
| 104 | * |
| 105 | * _(ty, TY, setgroup, setpriv, setpub) |
| 106 | * |
| 107 | * The @ty@ and @TY@ are lower- and upper-case versions of the key type name, |
| 108 | * and there should be @key_fetchdef@s called @ty_{priv,pub}fetch@. |
| 109 | * |
| 110 | * The @setgroup@, @setpriv@ and @setpub@ items are code fragments which are |
| 111 | * passed to @KLOAD@ to build appropriate key-loading methods. By the time |
| 112 | * these code fragments are run, the key has been unpacked from the incoming |
| 113 | * key data using @ty_whichfetch@ into a @ty_which@ structure named @p@. |
| 114 | * They can report errors by writing an appropriate token sequence to @e@ and |
| 115 | * jumping to @fail@. |
| 116 | */ |
| 117 | |
| 118 | #define KEYTYPES(_) \ |
| 119 | \ |
| 120 | /* --- Diffie-Hellman --- */ \ |
| 121 | \ |
| 122 | _(dh, DH, \ |
| 123 | { kd->g = group_prime(&p.dp); }, \ |
| 124 | { kd->kpriv = MP_COPY(p.x); }, \ |
| 125 | { if (G_FROMINT(kd->g, kd->kpub, p.y)) { \ |
| 126 | a_format(e, "bad-public-vector", A_END); \ |
| 127 | goto fail; \ |
| 128 | } \ |
| 129 | }) \ |
| 130 | \ |
| 131 | /* --- Elliptic curves --- */ \ |
| 132 | \ |
| 133 | _(ec, EC, \ |
| 134 | { ec_info ei; const char *err; \ |
| 135 | if ((err = ec_getinfo(&ei, p.cstr)) != 0) { \ |
| 136 | a_format(e, "decode-failed", "%s", err, A_END); \ |
| 137 | goto fail; \ |
| 138 | } \ |
| 139 | kd->g = group_ec(&ei); \ |
| 140 | }, \ |
| 141 | { kd->kpriv = MP_COPY(p.x); }, \ |
| 142 | { if (G_FROMEC(kd->g, kd->kpub, &p.p)) { \ |
| 143 | a_format(e, "bad-public-vector", A_END); \ |
| 144 | goto fail; \ |
| 145 | } \ |
| 146 | }) |
| 147 | |
| 148 | #define KEYTYPE_DEF(ty, TY, setgroup, setpriv, setpub) \ |
| 149 | KLOAD(ty, TY, priv, PRIV, setgroup, setpriv, \ |
| 150 | { G_EXP(kd->g, kd->kpub, kd->g->g, kd->kpriv); }) \ |
| 151 | KLOAD(ty, TY, pub, PUB, setgroup, { }, setpub) \ |
| 152 | static const kgops kg##ty##_ops = { #ty, kg##ty##_priv, kg##ty##_pub }; |
| 153 | KEYTYPES(KEYTYPE_DEF) |
| 154 | |
| 155 | /* --- Table of supported key types --- */ |
| 156 | |
| 157 | static const kgops *kgtab[] = { |
| 158 | #define KEYTYPE_ENTRY(ty, TY, setgroup, setpriv, setpub) &kg##ty##_ops, |
| 159 | KEYTYPES(KEYTYPE_ENTRY) |
| 160 | #undef KEYTYPE_ENTRY |
| 161 | 0 |
| 162 | }; |
| 163 | |
| 164 | /*----- Algswitch stuff ---------------------------------------------------*/ |
| 165 | |
| 166 | /* --- @algs_get@ --- * |
| 167 | * |
| 168 | * Arguments: @algswitch *a@ = where to put the algorithms |
| 169 | * @dstr *e@ = where to write errror tokens |
| 170 | * @key_file *kf@ = key file |
| 171 | * @key *k@ = key to inspect |
| 172 | * |
| 173 | * Returns: Zero if OK; nonzero on error. |
| 174 | * |
| 175 | * Use: Extracts an algorithm choice from a key. |
| 176 | */ |
| 177 | |
| 178 | static int algs_get(algswitch *a, dstr *e, key_file *kf, key *k) |
| 179 | { |
| 180 | const char *p; |
| 181 | const bulkcrypto *bulk; |
| 182 | char *q, *qq; |
| 183 | dstr d = DSTR_INIT; |
| 184 | int rc = -1; |
| 185 | |
| 186 | /* --- Hash function --- */ |
| 187 | |
| 188 | if ((p = key_getattr(kf, k, "hash")) == 0) p = "rmd160"; |
| 189 | if ((a->h = ghash_byname(p)) == 0) { |
| 190 | a_format(e, "unknown-hash", "%s", p, A_END); |
| 191 | goto done; |
| 192 | } |
| 193 | |
| 194 | /* --- Symmetric encryption for key derivation --- */ |
| 195 | |
| 196 | if ((p = key_getattr(kf, k, "mgf")) == 0) { |
| 197 | dstr_reset(&d); |
| 198 | dstr_putf(&d, "%s-mgf", a->h->name); |
| 199 | p = d.buf; |
| 200 | } |
| 201 | if ((a->mgf = gcipher_byname(p)) == 0) { |
| 202 | a_format(e, "unknown-mgf-cipher", "%s", p, A_END); |
| 203 | goto done; |
| 204 | } |
| 205 | |
| 206 | /* --- Bulk crypto transform --- */ |
| 207 | |
| 208 | if ((p = key_getattr(kf, k, "bulk")) == 0) p = "v0"; |
| 209 | for (bulk = bulktab; bulk->name && strcmp(p, bulk->name) != 0; bulk++); |
| 210 | if (!bulk->name) { |
| 211 | a_format(e, "unknown-bulk-transform", "%s", p, A_END); |
| 212 | goto done; |
| 213 | } |
| 214 | a->bulk = bulk; |
| 215 | |
| 216 | /* --- Symmetric encryption for bulk data --- */ |
| 217 | |
| 218 | if (!(a->bulk->prim & BCP_CIPHER)) |
| 219 | a->c = 0; |
| 220 | else { |
| 221 | if ((p = key_getattr(kf, k, "cipher")) == 0) p = "blowfish-cbc"; |
| 222 | if ((a->c = gcipher_byname(p)) == 0) { |
| 223 | a_format(e, "unknown-cipher", "%s", p, A_END); |
| 224 | goto done; |
| 225 | } |
| 226 | } |
| 227 | |
| 228 | /* --- Message authentication for bulk data --- */ |
| 229 | |
| 230 | if (!(a->bulk->prim & BCP_MAC)) { |
| 231 | a->m = 0; |
| 232 | a->tagsz = 0; |
| 233 | } else { |
| 234 | if ((p = key_getattr(kf, k, "mac")) != 0) { |
| 235 | dstr_reset(&d); |
| 236 | dstr_puts(&d, p); |
| 237 | if ((q = strchr(d.buf, '/')) != 0) |
| 238 | *q++ = 0; |
| 239 | if ((a->m = gmac_byname(d.buf)) == 0) { |
| 240 | a_format(e, "unknown-mac", "%s", d.buf, A_END); |
| 241 | goto done; |
| 242 | } |
| 243 | if (!q) |
| 244 | a->tagsz = a->m->hashsz; |
| 245 | else { |
| 246 | unsigned long n = strtoul(q, &qq, 0); |
| 247 | if (*qq) { |
| 248 | a_format(e, "bad-tag-length-string", "%s", q, A_END); |
| 249 | goto done; |
| 250 | } |
| 251 | if (n%8 || n/8 > a->m->hashsz) { |
| 252 | a_format(e, "bad-tag-length", "%lu", n, A_END); |
| 253 | goto done; |
| 254 | } |
| 255 | a->tagsz = n/8; |
| 256 | } |
| 257 | } else { |
| 258 | dstr_reset(&d); |
| 259 | dstr_putf(&d, "%s-hmac", a->h->name); |
| 260 | if ((a->m = gmac_byname(d.buf)) == 0) { |
| 261 | a_format(e, "no-hmac-for-hash", "%s", a->h->name, A_END); |
| 262 | goto done; |
| 263 | } |
| 264 | a->tagsz = a->h->hashsz/2; |
| 265 | } |
| 266 | } |
| 267 | |
| 268 | /* --- All done --- */ |
| 269 | |
| 270 | rc = 0; |
| 271 | done: |
| 272 | dstr_destroy(&d); |
| 273 | return (rc); |
| 274 | } |
| 275 | |
| 276 | /* --- @algs_check@ --- * |
| 277 | * |
| 278 | * Arguments: @algswitch *a@ = a choice of algorithms |
| 279 | * @dstr *e@ = where to write error tokens |
| 280 | * @const group *g@ = the group we're working in |
| 281 | * |
| 282 | * Returns: Zero if OK; nonzero on error. |
| 283 | * |
| 284 | * Use: Checks an algorithm choice for sensibleness. This also |
| 285 | * derives some useful information from the choices, and you |
| 286 | * must call this before committing the algorithm selection |
| 287 | * for use by @keyset@ functions. |
| 288 | */ |
| 289 | |
| 290 | static int algs_check(algswitch *a, dstr *e, const group *g) |
| 291 | { |
| 292 | /* --- Check the bulk crypto transform --- */ |
| 293 | |
| 294 | if (a->bulk->check(a, e)) return (-1); |
| 295 | |
| 296 | /* --- Derive the key sizes --- * |
| 297 | * |
| 298 | * Must ensure that we have non-empty keys. This isn't ideal, but it |
| 299 | * provides a handy sanity check. Also must be based on a 64- or 128-bit |
| 300 | * block cipher or we can't do the data expiry properly. |
| 301 | */ |
| 302 | |
| 303 | a->hashsz = a->h->hashsz; |
| 304 | if (a->c && (a->cksz = keysz(a->hashsz, a->c->keysz)) == 0) { |
| 305 | a_format(e, "cipher", "%s", a->c->name, |
| 306 | "no-key-size", "%lu", (unsigned long)a->hashsz, |
| 307 | A_END); |
| 308 | return (-1); |
| 309 | } |
| 310 | if (a->m && (a->mksz = keysz(a->hashsz, a->m->keysz)) == 0) { |
| 311 | a_format(e, "mac", "%s", a->m->name, |
| 312 | "no-key-size", "%lu", (unsigned long)a->hashsz, |
| 313 | A_END); |
| 314 | return (-1); |
| 315 | } |
| 316 | |
| 317 | /* --- Derive the data limit --- */ |
| 318 | |
| 319 | if (a->c && a->c->blksz < 16) a->expsz = MEG(64); |
| 320 | else a->expsz = MEG(2048); |
| 321 | |
| 322 | /* --- Ensure the MGF accepts hashes as keys --- */ |
| 323 | |
| 324 | if (keysz(a->hashsz, a->mgf->keysz) != a->hashsz) { |
| 325 | a_format(e, "mgf", "%s", a->mgf->name, |
| 326 | "restrictive-key-schedule", |
| 327 | A_END); |
| 328 | return (-1); |
| 329 | } |
| 330 | |
| 331 | /* --- All ship-shape and Bristol-fashion --- */ |
| 332 | |
| 333 | return (0); |
| 334 | } |
| 335 | |
| 336 | /* --- @km_samealgsp@ --- * |
| 337 | * |
| 338 | * Arguments: @const kdata *kdx, *kdy@ = two key data objects |
| 339 | * |
| 340 | * Returns: Nonzero if their two algorithm selections are the same. |
| 341 | * |
| 342 | * Use: Checks sameness of algorithm selections: used to ensure that |
| 343 | * peers are using sensible algorithms. |
| 344 | */ |
| 345 | |
| 346 | int km_samealgsp(const kdata *kdx, const kdata *kdy) |
| 347 | { |
| 348 | const algswitch *a = &kdx->algs, *aa = &kdy->algs; |
| 349 | |
| 350 | return (group_samep(kdx->g, kdy->g) && a->c == aa->c && |
| 351 | a->mgf == aa->mgf && a->h == aa->h && |
| 352 | a->m == aa->m && a->tagsz == aa->tagsz); |
| 353 | } |
| 354 | |
| 355 | /*----- Key data and key nodes --------------------------------------------*/ |
| 356 | |
| 357 | typedef struct keyhalf { |
| 358 | const char *kind; |
| 359 | int (*load)(const kgops *, key_data *, kdata *, dstr *, dstr *); |
| 360 | const char *kr; |
| 361 | key_file *kf; |
| 362 | fwatch w; |
| 363 | sym_table tab; |
| 364 | } keyhalf; |
| 365 | |
| 366 | /* --- @kh_loadpub@, @kh_loadpriv@ --- * |
| 367 | * |
| 368 | * Arguments: @const kgops *ko@ = key-group operations for key type |
| 369 | * @key_data *d@ = key data object as stored in keyring |
| 370 | * @kdata *kd@ = our key-data object to fill in |
| 371 | * @dstr *t@ = the key tag name |
| 372 | * @dstr *e@ = a string to write error tokens to |
| 373 | * |
| 374 | * Returns: Zero on success, @-1@ on error. |
| 375 | * |
| 376 | * Use: These functions handle the main difference between public and |
| 377 | * private key halves. They are responsible for setting @g@, |
| 378 | * @kpriv@ and @kpub@ appropriately in all keys, handling the |
| 379 | * mismatch between the largely half-indifferent calling code |
| 380 | * and the group-specific loading functions. |
| 381 | * |
| 382 | * The function @kh_loadpriv@ is also responsible for checking |
| 383 | * the group for goodness. We don't bother checking public |
| 384 | * keys, because each public key we actually end up using must |
| 385 | * share a group with a private key which we'll already have |
| 386 | * checked. |
| 387 | */ |
| 388 | |
| 389 | static int kh_loadpub(const kgops *ko, key_data *d, kdata *kd, |
| 390 | dstr *t, dstr *e) |
| 391 | { |
| 392 | int rc; |
| 393 | |
| 394 | if ((rc = ko->loadpub(d, kd, t, e)) != 0) |
| 395 | goto fail_0; |
| 396 | if (group_check(kd->g, kd->kpub)) { |
| 397 | a_format(e, "bad-public-group-element", A_END); |
| 398 | goto fail_1; |
| 399 | } |
| 400 | kd->kpriv = 0; |
| 401 | return (0); |
| 402 | |
| 403 | fail_1: |
| 404 | G_DESTROY(kd->g, kd->kpub); |
| 405 | G_DESTROYGROUP(kd->g); |
| 406 | fail_0: |
| 407 | return (-1); |
| 408 | } |
| 409 | |
| 410 | static int kh_loadpriv(const kgops *ko, key_data *d, kdata *kd, |
| 411 | dstr *t, dstr *e) |
| 412 | { |
| 413 | int rc; |
| 414 | const char *err; |
| 415 | |
| 416 | if ((rc = ko->loadpriv(d, kd, t, e)) != 0) |
| 417 | goto fail_0; |
| 418 | if ((err = G_CHECK(kd->g, &rand_global)) != 0) { |
| 419 | a_format(e, "bad-group", "%s", err, A_END); |
| 420 | goto fail_1; |
| 421 | } |
| 422 | return (0); |
| 423 | |
| 424 | fail_1: |
| 425 | mp_drop(kd->kpriv); |
| 426 | G_DESTROY(kd->g, kd->kpub); |
| 427 | G_DESTROYGROUP(kd->g); |
| 428 | fail_0: |
| 429 | return (-1); |
| 430 | } |
| 431 | |
| 432 | static struct keyhalf |
| 433 | priv = { "private", kh_loadpriv }, |
| 434 | pub = { "public", kh_loadpub }; |
| 435 | |
| 436 | /* --- @keymoan@ --- * |
| 437 | * |
| 438 | * Arguments: @const char *file@ = name of the file |
| 439 | * @int line@ = line number in file |
| 440 | * @const char *msg@ = error message |
| 441 | * @void *p@ = argument pointer (indicates which keyring) |
| 442 | * |
| 443 | * Returns: --- |
| 444 | * |
| 445 | * Use: Reports an error message about loading a key file. |
| 446 | */ |
| 447 | |
| 448 | static void keymoan(const char *file, int line, const char *msg, void *p) |
| 449 | { |
| 450 | keyhalf *kh = p; |
| 451 | |
| 452 | if (!line) { |
| 453 | a_warn("KEYMGMT", "%s-keyring", kh->kind, "%s", file, |
| 454 | "io-error", "?ERRNO", A_END); |
| 455 | } else { |
| 456 | a_warn("KEYMGMT", "%s-keyring", kh->kind, "%s", file, "line", "%d", line, |
| 457 | "%s", msg, A_END); |
| 458 | } |
| 459 | } |
| 460 | |
| 461 | /* --- @kh_reopen@ --- * |
| 462 | * |
| 463 | * Arguments: @keyhalf *kh@ = pointer to keyhalf structure |
| 464 | * |
| 465 | * Returns: Zero on success, @-1@ on error. |
| 466 | * |
| 467 | * Use: Reopens the key file for the appropriate key half. If this |
| 468 | * fails, everything is left as it was; if it succeeds, then the |
| 469 | * old file is closed (if it was non-null) and the new one put |
| 470 | * in its place. |
| 471 | */ |
| 472 | |
| 473 | static int kh_reopen(keyhalf *kh) |
| 474 | { |
| 475 | key_file *kf = CREATE(key_file); |
| 476 | |
| 477 | if (key_open(kf, kh->kr, KOPEN_READ, keymoan, kh)) { |
| 478 | a_warn("KEYMGMT", "%s-keyring", kh->kind, "%s", kh->kr, |
| 479 | "io-error", "?ERRNO", A_END); |
| 480 | DESTROY(kf); |
| 481 | return (-1); |
| 482 | } else { |
| 483 | if (kh->kf) { |
| 484 | key_close(kh->kf); |
| 485 | DESTROY(kh->kf); |
| 486 | } |
| 487 | kh->kf = kf; |
| 488 | return (0); |
| 489 | } |
| 490 | } |
| 491 | |
| 492 | /* --- @kh_init@ --- * |
| 493 | * |
| 494 | * Arguments: @keyhalf *kh@ = pointer to keyhalf structure to set up |
| 495 | * @const char *kr@ = name of the keyring file |
| 496 | * |
| 497 | * Returns: --- |
| 498 | * |
| 499 | * Use: Initialize a keyhalf structure, maintaining the private or |
| 500 | * public keys. Intended to be called during initialization: |
| 501 | * exits if there's some kind of problem. |
| 502 | */ |
| 503 | |
| 504 | static void kh_init(keyhalf *kh, const char *kr) |
| 505 | { |
| 506 | kh->kr = kr; |
| 507 | fwatch_init(&kh->w, kr); |
| 508 | sym_create(&kh->tab); |
| 509 | kh->kf = 0; |
| 510 | |
| 511 | if (kh_reopen(kh)) |
| 512 | die(EXIT_FAILURE, "failed to load %s keyring `%s'", kh->kind, kr); |
| 513 | } |
| 514 | |
| 515 | /* --- @kh_load@ --- * |
| 516 | * |
| 517 | * Arguments: @keyhalf *kh@ = pointer to keyhalf |
| 518 | * @const char *tag@ = key tag to be loaded |
| 519 | * @int complainp@ = whether to complain about missing keys |
| 520 | * |
| 521 | * Returns: Pointer to a @kdata@ structure if successful, or null on |
| 522 | * failure. |
| 523 | * |
| 524 | * Use: Attempts to load a key from the current key file. This |
| 525 | * function always reads data from the file: it's used when |
| 526 | * there's a cache miss from @kh_find@, and when refreshing the |
| 527 | * known keys in @kh_refresh@. The returned kdata has a |
| 528 | * reference count of exactly 1, and has no home knode. |
| 529 | */ |
| 530 | |
| 531 | static kdata *kh_load(keyhalf *kh, const char *tag, int complainp) |
| 532 | { |
| 533 | dstr t = DSTR_INIT; |
| 534 | dstr e = DSTR_INIT; |
| 535 | key *k; |
| 536 | key_data **d; |
| 537 | kdata *kd; |
| 538 | const char *ty; |
| 539 | const kgops **ko; |
| 540 | |
| 541 | /* --- Find the key and grab its tag --- */ |
| 542 | |
| 543 | if (key_qtag(kh->kf, tag, &t, &k, &d)) { |
| 544 | if (complainp) { |
| 545 | a_warn("KEYMGMT", "%s-keyring", kh->kind, "%s", kh->kr, |
| 546 | "key-not-found", "%s", tag, A_END); |
| 547 | } |
| 548 | goto fail_0; |
| 549 | } |
| 550 | |
| 551 | /* --- Find the key's group type and the appropriate operations --- * |
| 552 | * |
| 553 | * There are several places to look for the key type. The most obvious is |
| 554 | * the `kx-group' key attribute. But there's also the key type itself, for |
| 555 | * compatibility reasons. |
| 556 | */ |
| 557 | |
| 558 | ty = key_getattr(kh->kf, k, "kx-group"); |
| 559 | if (!ty && strncmp(k->type, "tripe-", 6) == 0) ty = k->type + 6; |
| 560 | if (!ty) ty = "dh"; |
| 561 | |
| 562 | for (ko = kgtab; *ko; ko++) |
| 563 | if (strcmp((*ko)->ty, ty) == 0) goto foundko; |
| 564 | a_warn("KEYMGMT", "%s-keyring", kh->kind, |
| 565 | "%s", kh->kr, "key", "%s", t.buf, |
| 566 | "unknown-group-type", "%s", ty, A_END); |
| 567 | goto fail_0; |
| 568 | |
| 569 | foundko: |
| 570 | kd = CREATE(kdata); |
| 571 | if (kh->load(*ko, *d, kd, &t, &e)) { |
| 572 | a_warn("KEYMGMT", "%s-keyring", kh->kind, |
| 573 | "%s", kh->kr, "key" "%s", t.buf, |
| 574 | "*%s", e.buf, A_END); |
| 575 | goto fail_1; |
| 576 | } |
| 577 | |
| 578 | if (algs_get(&kd->algs, &e, kh->kf, k) || |
| 579 | (kd->kpriv && algs_check(&kd->algs, &e, kd->g))) { |
| 580 | a_warn("KEYMGMT", "%s-keyring", kh->kind, |
| 581 | "%s", kh->kr, "key", "%s", t.buf, |
| 582 | "*%s", e.buf, A_END); |
| 583 | goto fail_2; |
| 584 | } |
| 585 | |
| 586 | kd->tag = xstrdup(t.buf); |
| 587 | kd->indexsz = mp_octets(kd->g->r); |
| 588 | kd->ref = 1; |
| 589 | kd->kn = 0; |
| 590 | kd->t_exp = k->exp; |
| 591 | |
| 592 | IF_TRACING(T_KEYMGMT, { |
| 593 | trace(T_KEYMGMT, "keymgmt: loaded %s key `%s'", kh->kind, t.buf); |
| 594 | IF_TRACING(T_CRYPTO, { |
| 595 | trace(T_CRYPTO, "crypto: r = %s", mpstr(kd->g->r)); |
| 596 | trace(T_CRYPTO, "crypto: h = %s", mpstr(kd->g->h)); |
| 597 | if (kd->kpriv) |
| 598 | trace(T_CRYPTO, "crypto: x = %s", mpstr(kd->kpriv)); |
| 599 | trace(T_CRYPTO, "crypto: cipher = %s", kd->algs.c->name); |
| 600 | trace(T_CRYPTO, "crypto: mgf = %s", kd->algs.mgf->name); |
| 601 | trace(T_CRYPTO, "crypto: hash = %s", kd->algs.h->name); |
| 602 | trace(T_CRYPTO, "crypto: mac = %s/%lu", |
| 603 | kd->algs.m->name, (unsigned long)kd->algs.tagsz * 8); |
| 604 | }) |
| 605 | }) |
| 606 | |
| 607 | goto done; |
| 608 | |
| 609 | fail_2: |
| 610 | if (kd->kpriv) mp_drop(kd->kpriv); |
| 611 | G_DESTROY(kd->g, kd->kpub); |
| 612 | G_DESTROYGROUP(kd->g); |
| 613 | fail_1: |
| 614 | DESTROY(kd); |
| 615 | fail_0: |
| 616 | kd = 0; |
| 617 | done: |
| 618 | dstr_destroy(&t); |
| 619 | dstr_destroy(&e); |
| 620 | return (kd); |
| 621 | } |
| 622 | |
| 623 | /* --- @kh_find@ --- * |
| 624 | * |
| 625 | * Arguments: @keyhalf *kh@ = pointer to the keyhalf |
| 626 | * @const char *tag@ = key to be obtained |
| 627 | * @int complainp@ = whether to complain about missing keys |
| 628 | * |
| 629 | * Returns: A pointer to the kdata, or null on error. |
| 630 | * |
| 631 | * Use: Obtains kdata, maybe from the cache. This won't update a |
| 632 | * stale cache entry, though @kh_refresh@ ought to have done |
| 633 | * that already. The returned kdata object may be shared with |
| 634 | * other users. (One of this function's responsibilities, over |
| 635 | * @kh_load@, is to set the home knode of a freshly loaded |
| 636 | * kdata.) |
| 637 | */ |
| 638 | |
| 639 | static kdata *kh_find(keyhalf *kh, const char *tag, int complainp) |
| 640 | { |
| 641 | knode *kn; |
| 642 | kdata *kd; |
| 643 | unsigned f; |
| 644 | |
| 645 | kn = sym_find(&kh->tab, tag, -1, sizeof(knode), &f); |
| 646 | |
| 647 | if (f) { |
| 648 | if (kn->f & KNF_BROKEN) { |
| 649 | T( if (complainp) |
| 650 | trace(T_KEYMGMT, "keymgmt: key `%s' marked as broken", tag); ) |
| 651 | return (0); |
| 652 | } |
| 653 | |
| 654 | kd = kn->kd; |
| 655 | if (kd) kd->ref++; |
| 656 | T( trace(T_KEYMGMT, "keymgmt: %scache hit for key `%s'", |
| 657 | kd ? "" : "negative ", tag); ) |
| 658 | return (kd); |
| 659 | } else { |
| 660 | kd = kh_load(kh, tag, complainp); |
| 661 | kn->kd = kd; |
| 662 | kn->kh = kh; |
| 663 | kn->f = 0; |
| 664 | if (!kd) |
| 665 | kn->f |= KNF_BROKEN; |
| 666 | else { |
| 667 | kd->kn = kn; |
| 668 | kd->ref++; |
| 669 | } |
| 670 | return (kd); |
| 671 | } |
| 672 | } |
| 673 | |
| 674 | /* --- @kh_refresh@ --- * |
| 675 | * |
| 676 | * Arguments: @keyhalf *kh@ = pointer to the keyhalf |
| 677 | * |
| 678 | * Returns: Zero if nothing needs to be done; nonzero if peers should |
| 679 | * refresh their keys. |
| 680 | * |
| 681 | * Use: Refreshes cached keys from files. |
| 682 | * |
| 683 | * Each active knode is examined to see if a new key is |
| 684 | * available: the return value is nonzero if any new keys are. |
| 685 | * A key is considered new if its algorithms, public key, or |
| 686 | * expiry time are/is different. |
| 687 | * |
| 688 | * Stub knodes (with no kdata attached) are removed, so that a |
| 689 | * later retry can succeed if the file has been fixed. (This |
| 690 | * doesn't count as a change, since no peers should be relying |
| 691 | * on a nonexistent key.) |
| 692 | */ |
| 693 | |
| 694 | static int kh_refresh(keyhalf *kh) |
| 695 | { |
| 696 | knode *kn; |
| 697 | kdata *kd; |
| 698 | sym_iter i; |
| 699 | int changep = 0; |
| 700 | |
| 701 | if (!fwatch_update(&kh->w, kh->kr) || kh_reopen(kh)) |
| 702 | return (0); |
| 703 | |
| 704 | T( trace(T_KEYMGMT, "keymgmt: rescan %s keyring `%s'", kh->kind, kh->kr); ) |
| 705 | for (sym_mkiter(&i, &kh->tab); (kn = sym_next(&i)) != 0; ) { |
| 706 | if (!kn->kd) { |
| 707 | T( trace(T_KEYMGMT, "keymgmt: discard stub entry for key `%s'", |
| 708 | SYM_NAME(kn)); ) |
| 709 | sym_remove(&kh->tab, kn); |
| 710 | continue; |
| 711 | } |
| 712 | if ((kd = kh_load(kh, SYM_NAME(kn), 1)) == 0) { |
| 713 | if (!(kn->f & KNF_BROKEN)) { |
| 714 | T( trace(T_KEYMGMT, "keymgmt: failed to load new key `%s': " |
| 715 | "marking it as broken", |
| 716 | SYM_NAME(kn)); ) |
| 717 | kn->f |= KNF_BROKEN; |
| 718 | } |
| 719 | continue; |
| 720 | } |
| 721 | kn->f &= ~KNF_BROKEN; |
| 722 | if (kd->t_exp == kn->kd->t_exp && |
| 723 | km_samealgsp(kd, kn->kd) && |
| 724 | G_EQ(kd->g, kd->kpub, kn->kd->kpub)) { |
| 725 | T( trace(T_KEYMGMT, "keymgmt: key `%s' unchanged", SYM_NAME(kn)); ) |
| 726 | continue; |
| 727 | } |
| 728 | T( trace(T_KEYMGMT, "keymgmt: loaded new version of key `%s'", |
| 729 | SYM_NAME(kn)); ) |
| 730 | km_unref(kn->kd); |
| 731 | kd->kn = kn; |
| 732 | kn->kd = kd; |
| 733 | changep = 1; |
| 734 | } |
| 735 | |
| 736 | return (changep); |
| 737 | } |
| 738 | |
| 739 | /*----- Main code ---------------------------------------------------------*/ |
| 740 | |
| 741 | const char *tag_priv; |
| 742 | kdata *master; |
| 743 | |
| 744 | /* --- @km_init@ --- * |
| 745 | * |
| 746 | * Arguments: @const char *privkr@ = private keyring file |
| 747 | * @const char *pubkr@ = public keyring file |
| 748 | * @const char *ptag@ = default private-key tag |
| 749 | * |
| 750 | * Returns: --- |
| 751 | * |
| 752 | * Use: Initializes the key-management machinery, loading the |
| 753 | * keyrings and so on. |
| 754 | */ |
| 755 | |
| 756 | void km_init(const char *privkr, const char *pubkr, const char *ptag) |
| 757 | { |
| 758 | const gchash *const *hh; |
| 759 | |
| 760 | for (hh = ghashtab; *hh; hh++) { |
| 761 | if ((*hh)->hashsz > MAXHASHSZ) { |
| 762 | die(EXIT_FAILURE, "INTERNAL ERROR: %s hash length %lu > MAXHASHSZ %d", |
| 763 | (*hh)->name, (unsigned long)(*hh)->hashsz, MAXHASHSZ); |
| 764 | } |
| 765 | } |
| 766 | |
| 767 | kh_init(&priv, privkr); |
| 768 | kh_init(&pub, pubkr); |
| 769 | |
| 770 | tag_priv = ptag; |
| 771 | if ((master = km_findpriv(ptag)) == 0) exit(EXIT_FAILURE); |
| 772 | } |
| 773 | |
| 774 | /* --- @km_reload@ --- * |
| 775 | * |
| 776 | * Arguments: --- |
| 777 | * |
| 778 | * Returns: Zero if OK, nonzero to force reloading of keys. |
| 779 | * |
| 780 | * Use: Checks the keyrings to see if they need reloading. |
| 781 | */ |
| 782 | |
| 783 | int km_reload(void) |
| 784 | { |
| 785 | int changep = 0; |
| 786 | kdata *kd; |
| 787 | |
| 788 | if (kh_refresh(&priv)) { |
| 789 | changep = 1; |
| 790 | kd = master->kn->kd; |
| 791 | if (kd != master) { |
| 792 | km_unref(master); |
| 793 | km_ref(kd); |
| 794 | master = kd; |
| 795 | } |
| 796 | } |
| 797 | if (kh_refresh(&pub)) |
| 798 | changep = 1; |
| 799 | return (changep); |
| 800 | } |
| 801 | |
| 802 | /* --- @km_findpub@, @km_findpriv@ --- * |
| 803 | * |
| 804 | * Arguments: @const char *tag@ = key tag to load |
| 805 | * |
| 806 | * Returns: Pointer to the kdata object if successful, or null on error. |
| 807 | * |
| 808 | * Use: Fetches a public or private key from the keyring. |
| 809 | */ |
| 810 | |
| 811 | kdata *km_findpub(const char *tag) { return (kh_find(&pub, tag, 1)); } |
| 812 | |
| 813 | kdata *km_findpriv(const char *tag) |
| 814 | { |
| 815 | kdata *kd; |
| 816 | |
| 817 | /* Unpleasantness for the sake of compatibility. */ |
| 818 | if (!tag && (kd = kh_find(&priv, "tripe", 0)) != 0) return (kd); |
| 819 | else return (kh_find(&priv, tag ? tag : "tripe-dh", 1)); |
| 820 | } |
| 821 | |
| 822 | /* --- @km_tag@ --- * |
| 823 | * |
| 824 | * Arguments: @kdata *kd@ - pointer to the kdata object |
| 825 | * |
| 826 | * Returns: A pointer to the short tag by which the kdata was loaded. |
| 827 | */ |
| 828 | |
| 829 | const char *km_tag(kdata *kd) { return (SYM_NAME(kd->kn)); } |
| 830 | |
| 831 | /* --- @km_ref@ --- * |
| 832 | * |
| 833 | * Arguments: @kdata *kd@ = pointer to the kdata object |
| 834 | * |
| 835 | * Returns: --- |
| 836 | * |
| 837 | * Use: Claim a new reference to a kdata object. |
| 838 | */ |
| 839 | |
| 840 | void km_ref(kdata *kd) { kd->ref++; } |
| 841 | |
| 842 | /* --- @km_unref@ --- * |
| 843 | * |
| 844 | * Arguments: @kdata *kd@ = pointer to the kdata object |
| 845 | * |
| 846 | * Returns: --- |
| 847 | * |
| 848 | * Use: Releases a reference to a kdata object. |
| 849 | */ |
| 850 | |
| 851 | void km_unref(kdata *kd) |
| 852 | { |
| 853 | if (--kd->ref) return; |
| 854 | if (kd->kpriv) mp_drop(kd->kpriv); |
| 855 | G_DESTROY(kd->g, kd->kpub); |
| 856 | xfree(kd->tag); |
| 857 | G_DESTROYGROUP(kd->g); |
| 858 | } |
| 859 | |
| 860 | /*----- That's all, folks -------------------------------------------------*/ |