| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: keymgmt.c,v 1.4 2004/04/03 12:35:13 mdw Exp $ |
| 4 | * |
| 5 | * Key loading and storing |
| 6 | * |
| 7 | * (c) 2001 Straylight/Edgeware |
| 8 | */ |
| 9 | |
| 10 | /*----- Licensing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of Trivial IP Encryption (TrIPE). |
| 13 | * |
| 14 | * TrIPE is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU General Public License as published by |
| 16 | * the Free Software Foundation; either version 2 of the License, or |
| 17 | * (at your option) any later version. |
| 18 | * |
| 19 | * TrIPE is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU General Public License |
| 25 | * along with TrIPE; if not, write to the Free Software Foundation, |
| 26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 27 | */ |
| 28 | |
| 29 | /*----- Revision history --------------------------------------------------* |
| 30 | * |
| 31 | * $Log: keymgmt.c,v $ |
| 32 | * Revision 1.4 2004/04/03 12:35:13 mdw |
| 33 | * Support elliptic curve key exchange. |
| 34 | * |
| 35 | * Revision 1.3 2001/06/22 19:40:36 mdw |
| 36 | * Support expiry of other peers' public keys. |
| 37 | * |
| 38 | * Revision 1.2 2001/06/19 22:07:09 mdw |
| 39 | * Cosmetic fixes. |
| 40 | * |
| 41 | * Revision 1.1 2001/02/03 20:26:37 mdw |
| 42 | * Initial checkin. |
| 43 | * |
| 44 | */ |
| 45 | |
| 46 | /*----- Header files ------------------------------------------------------*/ |
| 47 | |
| 48 | #include "tripe.h" |
| 49 | |
| 50 | /*----- Global variables --------------------------------------------------*/ |
| 51 | |
| 52 | group *gg; |
| 53 | mp *kpriv; |
| 54 | |
| 55 | /*----- Static variables --------------------------------------------------*/ |
| 56 | |
| 57 | static key_file *kf_pub; |
| 58 | static const char *kr_priv, *kr_pub, *tag_priv; |
| 59 | static fwatch w_priv, w_pub; |
| 60 | |
| 61 | /*----- Key groups --------------------------------------------------------*/ |
| 62 | |
| 63 | typedef struct kgops { |
| 64 | const char *ty; |
| 65 | const char *(*loadpriv)(key_data *, group **, mp **, dstr *); |
| 66 | const char *(*loadpub)(key_data *, group **, ge **, dstr *); |
| 67 | } kgops; |
| 68 | |
| 69 | /* --- Diffie-Hellman --- */ |
| 70 | |
| 71 | static const char *kgdh_priv(key_data *kd, group **g, mp **x, dstr *t) |
| 72 | { |
| 73 | key_packstruct kps[DH_PRIVFETCHSZ]; |
| 74 | key_packdef *kp; |
| 75 | dh_priv dp; |
| 76 | const char *e; |
| 77 | int rc; |
| 78 | |
| 79 | kp = key_fetchinit(dh_privfetch, kps, &dp); |
| 80 | if ((rc = key_unpack(kp, kd, t)) != 0) { |
| 81 | e = key_strerror(rc); |
| 82 | goto done; |
| 83 | } |
| 84 | *g = group_prime(&dp.dp); |
| 85 | *x = MP_COPY(dp.x); |
| 86 | e = 0; |
| 87 | done: |
| 88 | key_fetchdone(kp); |
| 89 | return (e); |
| 90 | } |
| 91 | |
| 92 | static const char *kgdh_pub(key_data *kd, group **g, ge **p, dstr *t) |
| 93 | { |
| 94 | key_packstruct kps[DH_PUBFETCHSZ]; |
| 95 | key_packdef *kp; |
| 96 | dh_pub dp; |
| 97 | const char *e; |
| 98 | int rc; |
| 99 | |
| 100 | kp = key_fetchinit(dh_pubfetch, kps, &dp); |
| 101 | if ((rc = key_unpack(kp, kd, t)) != 0) { |
| 102 | e = key_strerror(rc); |
| 103 | goto done; |
| 104 | } |
| 105 | *g = group_prime(&dp.dp); |
| 106 | *p = G_CREATE(*g); |
| 107 | if (G_FROMINT(*g, *p, dp.y)) { |
| 108 | e = "bad public value"; |
| 109 | goto done; |
| 110 | } |
| 111 | e = 0; |
| 112 | done: |
| 113 | key_fetchdone(kp); |
| 114 | return (e); |
| 115 | } |
| 116 | |
| 117 | static const kgops kgdh_ops = { "tripe-dh", kgdh_priv, kgdh_pub }; |
| 118 | |
| 119 | /* --- Elliptic curve --- */ |
| 120 | |
| 121 | static const char *kgec_priv(key_data *kd, group **g, mp **x, dstr *t) |
| 122 | { |
| 123 | key_packstruct kps[EC_PRIVFETCHSZ]; |
| 124 | key_packdef *kp; |
| 125 | ec_priv ep; |
| 126 | ec_info ei; |
| 127 | const char *e; |
| 128 | int rc; |
| 129 | |
| 130 | kp = key_fetchinit(ec_privfetch, kps, &ep); |
| 131 | if ((rc = key_unpack(kp, kd, t)) != 0) { |
| 132 | e = key_strerror(rc); |
| 133 | goto done; |
| 134 | } |
| 135 | if ((e = ec_getinfo(&ei, ep.cstr)) != 0) |
| 136 | goto done; |
| 137 | *g = group_ec(&ei); |
| 138 | *x = MP_COPY(ep.x); |
| 139 | e = 0; |
| 140 | done: |
| 141 | key_fetchdone(kp); |
| 142 | return (e); |
| 143 | } |
| 144 | |
| 145 | static const char *kgec_pub(key_data *kd, group **g, ge **p, dstr *t) |
| 146 | { |
| 147 | key_packstruct kps[EC_PUBFETCHSZ]; |
| 148 | key_packdef *kp; |
| 149 | ec_pub ep; |
| 150 | ec_info ei; |
| 151 | const char *e; |
| 152 | int rc; |
| 153 | |
| 154 | kp = key_fetchinit(ec_pubfetch, kps, &ep); |
| 155 | if ((rc = key_unpack(kp, kd, t)) != 0) { |
| 156 | e = key_strerror(rc); |
| 157 | goto done; |
| 158 | } |
| 159 | if ((e = ec_getinfo(&ei, ep.cstr)) != 0) |
| 160 | goto done; |
| 161 | *g = group_ec(&ei); |
| 162 | *p = G_CREATE(*g); |
| 163 | if (G_FROMEC(*g, *p, &ep.p)) { |
| 164 | e = "bad public point"; |
| 165 | goto done; |
| 166 | } |
| 167 | e = 0; |
| 168 | done: |
| 169 | key_fetchdone(kp); |
| 170 | return (e); |
| 171 | } |
| 172 | |
| 173 | static const kgops kgec_ops = { "tripe-ec", kgec_priv, kgec_pub }; |
| 174 | |
| 175 | /* --- Table of supported key types --- */ |
| 176 | |
| 177 | static const kgops *kgtab[] = { &kgdh_ops, &kgec_ops, 0 }; |
| 178 | |
| 179 | /*----- Main code ---------------------------------------------------------*/ |
| 180 | |
| 181 | /* --- @keymoan@ --- * |
| 182 | * |
| 183 | * Arguments: @const char *file@ = name of the file |
| 184 | * @int line@ = line number in file |
| 185 | * @const char *msg@ = error message |
| 186 | * @void *p@ = argument pointer |
| 187 | * |
| 188 | * Returns: --- |
| 189 | * |
| 190 | * Use: Reports an error message about loading a key file. |
| 191 | */ |
| 192 | |
| 193 | static void keymoan(const char *file, int line, const char *msg, void *p) |
| 194 | { a_warn("%s:%i: error: %s", file, line, msg); } |
| 195 | |
| 196 | /* --- @loadpriv@ --- * |
| 197 | * |
| 198 | * Arguments: @dstr *d@ = string to write errors in |
| 199 | * |
| 200 | * Returns: Zero if OK, nonzero on error. |
| 201 | * |
| 202 | * Use: Loads the private key from its keyfile. |
| 203 | */ |
| 204 | |
| 205 | static int loadpriv(dstr *d) |
| 206 | { |
| 207 | key_file kf; |
| 208 | key *k; |
| 209 | key_data *kd; |
| 210 | dstr t = DSTR_INIT; |
| 211 | group *g = 0; |
| 212 | mp *x = 0; |
| 213 | int rc = -1; |
| 214 | const kgops **ko; |
| 215 | const char *e; |
| 216 | |
| 217 | /* --- Open the private key file --- */ |
| 218 | |
| 219 | if (key_open(&kf, kr_priv, KOPEN_READ, keymoan, 0)) { |
| 220 | dstr_putf(d, "error reading private keyring `%s': %s", |
| 221 | kr_priv, strerror(errno)); |
| 222 | goto done_0; |
| 223 | } |
| 224 | |
| 225 | /* --- Find the private key --- */ |
| 226 | |
| 227 | if (key_qtag(&kf, tag_priv, &t, &k, &kd)) { |
| 228 | dstr_putf(d, "private key `%s' not found in keyring `%s'", |
| 229 | tag_priv, kr_priv); |
| 230 | goto done_1; |
| 231 | } |
| 232 | |
| 233 | /* --- Look up the key type in the table --- */ |
| 234 | |
| 235 | for (ko = kgtab; *ko; ko++) { |
| 236 | if (strcmp((*ko)->ty, k->type) == 0) |
| 237 | goto tymatch; |
| 238 | } |
| 239 | dstr_putf(d, "private key `%s' has unknown type `%s'", t.buf, k->type); |
| 240 | goto done_1; |
| 241 | tymatch:; |
| 242 | |
| 243 | /* --- Load the key --- */ |
| 244 | |
| 245 | if ((e = (*ko)->loadpriv(kd, &g, &x, &t)) != 0) { |
| 246 | dstr_putf(d, "error reading private key `%s': %s", t.buf, e); |
| 247 | goto done_1; |
| 248 | } |
| 249 | |
| 250 | /* --- Check that the key is sensible --- */ |
| 251 | |
| 252 | if ((e = G_CHECK(g, &rand_global)) != 0) { |
| 253 | dstr_putf(d, "bad group in private key `%s': %s", t.buf, e); |
| 254 | goto done_1; |
| 255 | } |
| 256 | |
| 257 | /* --- Good, we're happy --- * |
| 258 | * |
| 259 | * Dodginess! We change the group over here, but don't free any old group |
| 260 | * elements. This assumes that the new group is basically the same as the |
| 261 | * old one, and will happily adopt the existing elements. If it isn't, |
| 262 | * then we lose badly. Check this, then. |
| 263 | */ |
| 264 | |
| 265 | if (gg) { |
| 266 | if (!group_samep(g, gg)) { |
| 267 | dstr_putf(d, "private key `%s' has different group", t.buf); |
| 268 | goto done_1; |
| 269 | } |
| 270 | G_DESTROYGROUP(gg); |
| 271 | } |
| 272 | if (kpriv) |
| 273 | mp_drop(kpriv); |
| 274 | |
| 275 | /* --- Dump out the group --- */ |
| 276 | |
| 277 | IF_TRACING(T_KEYMGMT, { |
| 278 | trace(T_KEYMGMT, "keymgmt: extracted private key `%s'", t.buf); |
| 279 | IF_TRACING(T_CRYPTO, { |
| 280 | trace(T_CRYPTO, "crypto: r = %s", mpstr(g->r)); |
| 281 | trace(T_CRYPTO, "crypto: h = %s", mpstr(g->h)); |
| 282 | trace(T_CRYPTO, "crypto: x = %s", mpstr(x)); |
| 283 | }) |
| 284 | }) |
| 285 | |
| 286 | /* --- Success! --- */ |
| 287 | |
| 288 | gg = g; g = 0; |
| 289 | kpriv = x; x = 0; |
| 290 | rc = 0; |
| 291 | |
| 292 | /* --- Tidy up --- */ |
| 293 | |
| 294 | done_1: |
| 295 | key_close(&kf); |
| 296 | done_0: |
| 297 | dstr_destroy(&t); |
| 298 | if (x) mp_drop(x); |
| 299 | if (g) G_DESTROYGROUP(g); |
| 300 | return (rc); |
| 301 | } |
| 302 | |
| 303 | /* --- @loadpub@ --- * |
| 304 | * |
| 305 | * Arguments: @dstr *d@ = string to write errors to |
| 306 | * |
| 307 | * Returns: Zero if OK, nonzero on error. |
| 308 | * |
| 309 | * Use: Reloads the public keyring. |
| 310 | */ |
| 311 | |
| 312 | static int loadpub(dstr *d) |
| 313 | { |
| 314 | key_file *kf = CREATE(key_file); |
| 315 | |
| 316 | if (key_open(kf, kr_pub, KOPEN_READ, keymoan, 0)) { |
| 317 | dstr_putf(d, "error reading public keyring `%s': %s", |
| 318 | kr_pub, strerror(errno)); |
| 319 | DESTROY(kf); |
| 320 | return (-1); |
| 321 | } |
| 322 | kf_pub = kf; |
| 323 | T( trace(T_KEYMGMT, "keymgmt: loaded public keyring `%s'", kr_pub); ) |
| 324 | return (0); |
| 325 | } |
| 326 | |
| 327 | /* --- @km_interval@ --- * |
| 328 | * |
| 329 | * Arguments: --- |
| 330 | * |
| 331 | * Returns: Zero if OK, nonzero to force reloading of keys. |
| 332 | * |
| 333 | * Use: Called on the interval timer to perform various useful jobs. |
| 334 | */ |
| 335 | |
| 336 | int km_interval(void) |
| 337 | { |
| 338 | dstr d = DSTR_INIT; |
| 339 | key_file *kf; |
| 340 | int reload = 0; |
| 341 | |
| 342 | /* --- Check the private key first --- */ |
| 343 | |
| 344 | if (fwatch_update(&w_priv, kr_priv)) { |
| 345 | T( trace(T_KEYMGMT, "keymgmt: private keyring updated: reloading..."); ) |
| 346 | DRESET(&d); |
| 347 | if (loadpriv(&d)) |
| 348 | a_warn("%s -- ignoring changes", d.buf); |
| 349 | else |
| 350 | reload = 1; |
| 351 | } |
| 352 | |
| 353 | /* --- Now check the public keys --- */ |
| 354 | |
| 355 | if (fwatch_update(&w_pub, kr_pub)) { |
| 356 | T( trace(T_KEYMGMT, "keymgmt: public keyring updated: reloading..."); ) |
| 357 | kf = kf_pub; |
| 358 | DRESET(&d); |
| 359 | if (loadpub(&d)) |
| 360 | a_warn("%s -- ignoring changes", d.buf); |
| 361 | else { |
| 362 | reload = 1; |
| 363 | key_close(kf); |
| 364 | DESTROY(kf); |
| 365 | } |
| 366 | } |
| 367 | |
| 368 | /* --- Done --- */ |
| 369 | |
| 370 | return (reload); |
| 371 | } |
| 372 | |
| 373 | /* --- @km_init@ --- * |
| 374 | * |
| 375 | * Arguments: @const char *priv@ = private keyring file |
| 376 | * @const char *pub@ = public keyring file |
| 377 | * @const char *tag@ = tag to load |
| 378 | * |
| 379 | * Returns: --- |
| 380 | * |
| 381 | * Use: Initializes, and loads the private key. |
| 382 | */ |
| 383 | |
| 384 | void km_init(const char *priv, const char *pub, const char *tag) |
| 385 | { |
| 386 | dstr d = DSTR_INIT; |
| 387 | |
| 388 | kr_priv = priv; |
| 389 | kr_pub = pub; |
| 390 | tag_priv = tag; |
| 391 | fwatch_init(&w_priv, kr_priv); |
| 392 | fwatch_init(&w_pub, kr_pub); |
| 393 | |
| 394 | DRESET(&d); |
| 395 | if (loadpriv(&d)) |
| 396 | die(EXIT_FAILURE, "%s", d.buf); |
| 397 | if (loadpub(&d)) |
| 398 | die(EXIT_FAILURE, "%s", d.buf); |
| 399 | } |
| 400 | |
| 401 | /* --- @km_getpubkey@ --- * |
| 402 | * |
| 403 | * Arguments: @const char *tag@ = public key tag to load |
| 404 | * @ge *kpub@ = where to put the public key |
| 405 | * @time_t *t_exp@ = where to put the expiry time |
| 406 | * |
| 407 | * Returns: Zero if OK, nonzero if it failed. |
| 408 | * |
| 409 | * Use: Fetches a public key from the keyring. |
| 410 | */ |
| 411 | |
| 412 | int km_getpubkey(const char *tag, ge *kpub, time_t *t_exp) |
| 413 | { |
| 414 | key *k; |
| 415 | key_data *kd; |
| 416 | dstr t = DSTR_INIT; |
| 417 | const kgops **ko; |
| 418 | const char *e; |
| 419 | group *g = 0; |
| 420 | ge *p = 0; |
| 421 | int rc = -1; |
| 422 | |
| 423 | /* --- Find the key --- */ |
| 424 | |
| 425 | if (key_qtag(kf_pub, tag, &t, &k, &kd)) { |
| 426 | a_warn("private key `%s' not found in keyring `%s'", tag_priv, kr_priv); |
| 427 | goto done; |
| 428 | } |
| 429 | |
| 430 | /* --- Look up the key type in the table --- */ |
| 431 | |
| 432 | for (ko = kgtab; *ko; ko++) { |
| 433 | if (strcmp((*ko)->ty, k->type) == 0) |
| 434 | goto tymatch; |
| 435 | } |
| 436 | a_warn("public key `%s' has unknown type `%s'", t.buf, k->type); |
| 437 | goto done; |
| 438 | tymatch:; |
| 439 | |
| 440 | /* --- Load the key --- */ |
| 441 | |
| 442 | if ((e = (*ko)->loadpub(kd, &g, &p, &t)) != 0) { |
| 443 | a_warn("error reading public key `%s': %s", t.buf, e); |
| 444 | goto done; |
| 445 | } |
| 446 | |
| 447 | /* --- Ensure that the group is correct --- * |
| 448 | * |
| 449 | * Dodginess! We assume that if this works, our global group is willing to |
| 450 | * adopt this public element. Probably reasonable. |
| 451 | */ |
| 452 | |
| 453 | if (!group_samep(gg, g)) { |
| 454 | a_warn("public key `%s' has incorrect group", t.buf); |
| 455 | goto done; |
| 456 | } |
| 457 | |
| 458 | /* --- Check the public group element --- */ |
| 459 | |
| 460 | if (group_check(gg, p)) { |
| 461 | a_warn("public key `%s' has bad public group element", t.buf); |
| 462 | goto done; |
| 463 | } |
| 464 | |
| 465 | /* --- Dump the public key --- */ |
| 466 | |
| 467 | IF_TRACING(T_KEYMGMT, { |
| 468 | trace(T_KEYMGMT, "keymgmt: extracted public key `%s'", t.buf); |
| 469 | trace(T_CRYPTO, "crypto: p = %s", gestr(gg, p)); |
| 470 | }) |
| 471 | |
| 472 | /* --- OK, accept the public key --- */ |
| 473 | |
| 474 | *t_exp = k->exp; |
| 475 | G_COPY(gg, kpub, p); |
| 476 | rc = 0; |
| 477 | |
| 478 | /* --- Tidy up --- */ |
| 479 | |
| 480 | done: |
| 481 | if (p) G_DESTROY(g, p); |
| 482 | if (g) G_DESTROYGROUP(g); |
| 483 | dstr_destroy(&t); |
| 484 | return (rc); |
| 485 | } |
| 486 | |
| 487 | /*----- That's all, folks -------------------------------------------------*/ |