mdw@git.distorted.org.uk Git - catacomb/blob - progs/cc-sig.c

   1 /* -*-c-*-
   2  *
   3  * Catcrypt signatures
   4  *
   5  * (c) 2004 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb 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 Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #define _FILE_OFFSET_BITS 64
  31
  32 #include <stdlib.h>
  33
  34 #include <mLib/report.h>
  35
  36 #include "rand.h"
  37 #include "sha.h"
  38 #include "has160.h"
  39 #include "sha512.h"
  40
  41 #include "ct.h"
  42 #include "ec.h"
  43 #include "ec-keys.h"
  44 #include "dh.h"
  45 #include "gdsa.h"
  46 #include "gkcdsa.h"
  47 #include "rsa.h"
  48 #include "ed25519.h"
  49
  50 #include "cc.h"
  51
  52 /*----- Main code ---------------------------------------------------------*/
  53
  54 /* --- RSA PKCS1 --- */
  55
  56 typedef struct rsap1_sigctx {
  57   sig s;
  58   rsa_privctx rp;
  59   pkcs1 p1;
  60 } rsap1_sigctx;
  61
  62 static sig *rsap1_siginit(key *k, void *kd, const gchash *hc)
  63 {
  64   rsap1_sigctx *rs = CREATE(rsap1_sigctx);
  65   rsa_privcreate(&rs->rp, kd, &rand_global);
  66   rs->p1.r = &rand_global;
  67   rs->p1.ep = hc->name;
  68   rs->p1.epsz = strlen(hc->name) + 1;
  69   rs->s.h = 0;
  70   return (&rs->s);
  71 }
  72
  73 static int rsap1_sigdoit(sig *s, dstr *d)
  74 {
  75   rsap1_sigctx *rs = (rsap1_sigctx *)s;
  76   size_t n;
  77   mp *m = rsa_sign(&rs->rp, MP_NEW,
  78                    GH_DONE(s->h, 0), GH_CLASS(s->h)->hashsz,
  79                    pkcs1_sigencode, &rs->p1);
  80   if (!m) return (-1);
  81   n = mp_octets(rs->rp.rp->n); dstr_ensure(d, n); mp_storeb(m, d->buf, n);
  82   d->len += n; mp_drop(m);
  83   return (0);
  84 }
  85
  86 static const char *rsa_lengthcheck(mp *n)
  87 {
  88   if (mp_bits(n) < 1024) return ("key too short");
  89   return (0);
  90 }
  91
  92 static const char *rsap1_sigcheck(sig *s)
  93 {
  94   rsap1_sigctx *rs = (rsap1_sigctx *)s;
  95   const char *e;
  96   if ((e = rsa_lengthcheck(rs->rp.rp->n)) != 0) return (e);
  97   return (0);
  98 }
  99
 100 static void rsap1_sigdestroy(sig *s)
 101 {
 102   rsap1_sigctx *rs = (rsap1_sigctx *)s;
 103   rsa_privdestroy(&rs->rp);
 104   DESTROY(rs);
 105 }
 106
 107 static const sigops rsap1_sig = {
 108   rsa_privfetch, sizeof(rsa_priv),
 109   rsap1_siginit, rsap1_sigdoit, rsap1_sigcheck, rsap1_sigdestroy
 110 };
 111
 112 typedef struct rsap1_vrfctx {
 113   sig s;
 114   rsa_pubctx rp;
 115   pkcs1 p1;
 116 } rsap1_vrfctx;
 117
 118 static sig *rsap1_vrfinit(key *k, void *kd, const gchash *hc)
 119 {
 120   rsap1_vrfctx *rv = CREATE(rsap1_vrfctx);
 121   rsa_pubcreate(&rv->rp, kd);
 122   rv->p1.r = &rand_global;
 123   rv->p1.ep = hc->name;
 124   rv->p1.epsz = strlen(hc->name) + 1;
 125   rv->s.h = 0;
 126   return (&rv->s);
 127 }
 128
 129 static int rsap1_vrfdoit(sig *s, dstr *d)
 130 {
 131   rsap1_vrfctx *rv = (rsap1_vrfctx *)s;
 132   mp *m = mp_loadb(MP_NEW, d->buf, d->len);
 133   int rc = rsa_verify(&rv->rp, m,
 134                       GH_DONE(s->h, 0), GH_CLASS(s->h)->hashsz,
 135                       0, pkcs1_sigdecode, &rv->p1);
 136   mp_drop(m);
 137   return (rc);
 138 }
 139
 140 static const char *rsap1_vrfcheck(sig *s)
 141 {
 142   rsap1_vrfctx *rv = (rsap1_vrfctx *)s;
 143   const char *e;
 144   if ((e = rsa_lengthcheck(rv->rp.rp->n)) != 0) return (e);
 145   return (0);
 146 }
 147
 148 static void rsap1_vrfdestroy(sig *s)
 149 {
 150   rsap1_vrfctx *rv = (rsap1_vrfctx *)s;
 151   rsa_pubdestroy(&rv->rp);
 152   DESTROY(rv);
 153 }
 154
 155 static const sigops rsap1_vrf = {
 156   rsa_pubfetch, sizeof(rsa_pub),
 157   rsap1_vrfinit, rsap1_vrfdoit, rsap1_vrfcheck, rsap1_vrfdestroy
 158 };
 159
 160 /* --- RSA PSS --- */
 161
 162 static const gccipher *getmgf(key *k, const gchash *hc)
 163 {
 164   dstr d = DSTR_INIT;
 165   const gccipher *gc;
 166   const char *mm;
 167
 168   if ((mm = key_getattr(0, k, "mgf")) == 0) {
 169     dstr_putf(&d, "%s-mgf", hc->name);
 170     mm = d.buf;
 171   }
 172   if ((gc = gcipher_byname(mm)) == 0)
 173     die(EXIT_FAILURE, "unknown encryption scheme `%s'", mm);
 174   dstr_destroy(&d);
 175   return (gc);
 176 }
 177
 178 typedef struct rsapss_sigctx {
 179   sig s;
 180   rsa_privctx rp;
 181   pss p;
 182 } rsapss_sigctx;
 183
 184 static sig *rsapss_siginit(key *k, void *kd, const gchash *hc)
 185 {
 186   rsapss_sigctx *rs = CREATE(rsapss_sigctx);
 187   rsa_privcreate(&rs->rp, kd, &rand_global);
 188   rs->s.h = 0;
 189   rs->p.r = &rand_global;
 190   rs->p.cc = getmgf(k, hc);
 191   rs->p.ch = hc;
 192   rs->p.ssz = hc->hashsz;
 193   return (&rs->s);
 194 }
 195
 196 static int rsapss_sigdoit(sig *s, dstr *d)
 197 {
 198   rsapss_sigctx *rs = (rsapss_sigctx *)s;
 199   size_t n;
 200   mp *m = rsa_sign(&rs->rp, MP_NEW,
 201                    GH_DONE(s->h, 0), GH_CLASS(s->h)->hashsz,
 202                    pss_encode, &rs->p);
 203   if (!m) return (-1);
 204   n = mp_octets(rs->rp.rp->n); dstr_ensure(d, n); mp_storeb(m, d->buf, n);
 205   d->len += n;  mp_drop(m);
 206   return (0);
 207 }
 208
 209 static const char *rsapss_sigcheck(sig *s)
 210 {
 211   rsapss_sigctx *rs = (rsapss_sigctx *)s;
 212   const char *e;
 213   if ((e = rsa_lengthcheck(rs->rp.rp->n)) != 0) return (e);
 214   return (0);
 215 }
 216
 217 static void rsapss_sigdestroy(sig *s)
 218 {
 219   rsapss_sigctx *rs = (rsapss_sigctx *)s;
 220   rsa_privdestroy(&rs->rp);
 221   DESTROY(rs);
 222 }
 223
 224 static const sigops rsapss_sig = {
 225   rsa_privfetch, sizeof(rsa_priv),
 226   rsapss_siginit, rsapss_sigdoit, rsapss_sigcheck, rsapss_sigdestroy
 227 };
 228
 229 typedef struct rsapss_vrfctx {
 230   sig s;
 231   rsa_pubctx rp;
 232   pss p;
 233 } rsapss_vrfctx;
 234
 235 static sig *rsapss_vrfinit(key *k, void *kd, const gchash *hc)
 236 {
 237   rsapss_vrfctx *rv = CREATE(rsapss_vrfctx);
 238   rsa_pubcreate(&rv->rp, kd);
 239   rv->s.h = 0;
 240   rv->p.r = &rand_global;
 241   rv->p.cc = getmgf(k, hc);
 242   rv->p.ch = hc;
 243   rv->p.ssz = hc->hashsz;
 244   return (&rv->s);
 245 }
 246
 247 static int rsapss_vrfdoit(sig *s, dstr *d)
 248 {
 249   rsapss_vrfctx *rv = (rsapss_vrfctx *)s;
 250   mp *m = mp_loadb(MP_NEW, d->buf, d->len);
 251   int rc = rsa_verify(&rv->rp, m,
 252                       GH_DONE(s->h, 0), GH_CLASS(s->h)->hashsz,
 253                       0, pss_decode, &rv->p);
 254   mp_drop(m);
 255   return (rc);
 256 }
 257
 258 static const char *rsapss_vrfcheck(sig *s)
 259 {
 260   rsapss_vrfctx *rv = (rsapss_vrfctx *)s;
 261   const char *e;
 262   if ((e = rsa_lengthcheck(rv->rp.rp->n)) != 0) return (e);
 263   return (0);
 264 }
 265
 266 static void rsapss_vrfdestroy(sig *s)
 267 {
 268   rsapss_vrfctx *rv = (rsapss_vrfctx *)s;
 269   rsa_pubdestroy(&rv->rp);
 270   DESTROY(rv);
 271 }
 272
 273 static const sigops rsapss_vrf = {
 274   rsa_pubfetch, sizeof(rsa_pub),
 275   rsapss_vrfinit, rsapss_vrfdoit, rsapss_vrfcheck, rsapss_vrfdestroy
 276 };
 277
 278 /* --- DSA and ECDSA --- */
 279
 280 typedef struct dsa_sigctx {
 281   sig s;
 282   gdsa g;
 283 } dsa_sigctx;
 284
 285 static void dsa_initcommon(dsa_sigctx *ds, const gchash *hc,
 286                            const char *ktag)
 287 {
 288   ds->g.r = &rand_global;
 289   ds->g.h = hc;
 290   ds->g.u = MP_NEW;
 291   ds->s.h = 0;
 292 }
 293
 294 static dsa_sigctx *dsa_doinit(key *k, const gprime_param *gp,
 295                               mp *y, const gchash *hc,
 296                               group *(*makegroup)(const gprime_param *),
 297                               const char *what)
 298 {
 299   dsa_sigctx *ds = CREATE(dsa_sigctx);
 300   dstr t = DSTR_INIT;
 301
 302   key_fulltag(k, &t);
 303   if ((ds->g.g = makegroup(gp)) == 0)
 304     die(EXIT_FAILURE, "bad %s group in key `%s'", what, t.buf);
 305   ds->g.p = G_CREATE(ds->g.g);
 306   if (G_FROMINT(ds->g.g, ds->g.p, y))
 307     die(EXIT_FAILURE, "bad public key in key `%s'", t.buf);
 308   dsa_initcommon(ds, hc, t.buf);
 309   dstr_destroy(&t);
 310   return (ds);
 311 }
 312
 313 static dsa_sigctx *ecdsa_doinit(key *k, const char *cstr,
 314                                 ec *y, const gchash *hc)
 315 {
 316   dsa_sigctx *ds = CREATE(dsa_sigctx);
 317   ec_info ei;
 318   const char *e;
 319   dstr t = DSTR_INIT;
 320
 321   key_fulltag(k, &t);
 322   if ((e = ec_getinfo(&ei, cstr)) != 0)
 323     die(EXIT_FAILURE, "bad curve in key `%s': %s", t.buf, e);
 324   ds->g.g = group_ec(&ei);
 325   ds->g.p = G_CREATE(ds->g.g);
 326   if (G_FROMEC(ds->g.g, ds->g.p, y))
 327     die(EXIT_FAILURE, "bad public key in key `%s'", t.buf);
 328   dsa_initcommon(ds, hc, t.buf);
 329   dstr_destroy(&t);
 330   return (ds);
 331 }
 332
 333 static sig *dsa_siginit(key *k, void *kd, const gchash *hc)
 334 {
 335   dh_priv *dp = kd;
 336   dsa_sigctx *ds = dsa_doinit(k, &dp->dp, dp->y, hc, group_prime, "prime");
 337   ds->g.u = MP_COPY(dp->x);
 338   return (&ds->s);
 339 }
 340
 341 static sig *bindsa_siginit(key *k, void *kd, const gchash *hc)
 342 {
 343   dh_priv *dp = kd;
 344   dsa_sigctx *ds = dsa_doinit(k, &dp->dp, dp->y, hc, group_binary, "binary");
 345   ds->g.u = MP_COPY(dp->x);
 346   return (&ds->s);
 347 }
 348
 349 static sig *ecdsa_siginit(key *k, void *kd, const gchash *hc)
 350 {
 351   ec_priv *ep = kd;
 352   dsa_sigctx *ds = ecdsa_doinit(k, ep->cstr, &ep->p, hc);
 353   ds->g.u = MP_COPY(ep->x);
 354   return (&ds->s);
 355 }
 356
 357 static int dsa_sigdoit(sig *s, dstr *d)
 358 {
 359   dsa_sigctx *ds = (dsa_sigctx *)s;
 360   gdsa_sig ss = GDSA_SIG_INIT;
 361   size_t n = mp_octets(ds->g.g->r);
 362
 363   gdsa_sign(&ds->g, &ss, GH_DONE(ds->s.h, 0), 0);
 364   dstr_ensure(d, 2 * n);
 365   mp_storeb(ss.r, d->buf, n);
 366   mp_storeb(ss.s, d->buf + n, n);
 367   d->len += 2 * n;
 368   mp_drop(ss.r); mp_drop(ss.s);
 369   return (0);
 370 }
 371
 372 static const char *dsa_sigcheck(sig *s)
 373 {
 374   dsa_sigctx *ds = (dsa_sigctx *)s;
 375   const char *e;
 376   if ((e = G_CHECK(ds->g.g, &rand_global)) != 0)
 377     return (0);
 378   if (group_check(ds->g.g, ds->g.p))
 379     return ("public key not in subgroup");
 380   return (0);
 381 }
 382
 383 static void dsa_sigdestroy(sig *s)
 384 {
 385   dsa_sigctx *ds = (dsa_sigctx *)s;
 386   G_DESTROY(ds->g.g, ds->g.p);
 387   mp_drop(ds->g.u);
 388   G_DESTROYGROUP(ds->g.g);
 389   DESTROY(ds);
 390 }
 391
 392 static const sigops dsa_sig = {
 393   dh_privfetch, sizeof(dh_priv),
 394   dsa_siginit, dsa_sigdoit, dsa_sigcheck, dsa_sigdestroy
 395 };
 396
 397 static const sigops bindsa_sig = {
 398   dh_privfetch, sizeof(dh_priv),
 399   bindsa_siginit, dsa_sigdoit, dsa_sigcheck, dsa_sigdestroy
 400 };
 401
 402 static const sigops ecdsa_sig = {
 403   ec_privfetch, sizeof(ec_priv),
 404   ecdsa_siginit, dsa_sigdoit, dsa_sigcheck, dsa_sigdestroy
 405 };
 406
 407 static sig *dsa_vrfinit(key *k, void *kd, const gchash *hc)
 408 {
 409   dh_pub *dp = kd;
 410   dsa_sigctx *ds = dsa_doinit(k, &dp->dp, dp->y, hc, group_prime, "prime");
 411   return (&ds->s);
 412 }
 413
 414 static sig *bindsa_vrfinit(key *k, void *kd, const gchash *hc)
 415 {
 416   dh_pub *dp = kd;
 417   dsa_sigctx *ds = dsa_doinit(k, &dp->dp, dp->y, hc, group_binary, "binary");
 418   return (&ds->s);
 419 }
 420
 421 static sig *ecdsa_vrfinit(key *k, void *kd, const gchash *hc)
 422 {
 423   ec_pub *ep = kd;
 424   dsa_sigctx *ds = ecdsa_doinit(k, ep->cstr, &ep->p, hc);
 425   return (&ds->s);
 426 }
 427
 428 static int dsa_vrfdoit(sig *s, dstr *d)
 429 {
 430   dsa_sigctx *ds = (dsa_sigctx *)s;
 431   gdsa_sig ss;
 432   size_t n = d->len/2;
 433   int rc;
 434
 435   ss.r = mp_loadb(MP_NEW, d->buf, n);
 436   ss.s = mp_loadb(MP_NEW, d->buf + n, d->len - n);
 437   rc = gdsa_verify(&ds->g, &ss, GH_DONE(ds->s.h, 0));
 438   mp_drop(ss.r); mp_drop(ss.s);
 439   return (rc);
 440 }
 441
 442 static const sigops dsa_vrf = {
 443   dh_pubfetch, sizeof(dh_pub),
 444   dsa_vrfinit, dsa_vrfdoit, dsa_sigcheck, dsa_sigdestroy
 445 };
 446
 447 static const sigops bindsa_vrf = {
 448   dh_pubfetch, sizeof(dh_pub),
 449   bindsa_vrfinit, dsa_vrfdoit, dsa_sigcheck, dsa_sigdestroy
 450 };
 451
 452 static const sigops ecdsa_vrf = {
 453   ec_pubfetch, sizeof(ec_pub),
 454   ecdsa_vrfinit, dsa_vrfdoit, dsa_sigcheck, dsa_sigdestroy
 455 };
 456
 457 /* --- KCDSA and ECKCDSA --- */
 458
 459 static void kcdsa_privkey(dsa_sigctx *ds, mp *x)
 460   { ds->g.u = mp_modinv(MP_NEW, x, ds->g.g->r); }
 461
 462 static void kcdsa_sethash(dsa_sigctx *ds, const gchash *hc)
 463   { ds->s.h = gkcdsa_beginhash(&ds->g); }
 464
 465 static sig *kcdsa_siginit(key *k, void *kd, const gchash *hc)
 466 {
 467   dh_priv *dp = kd;
 468   dsa_sigctx *ds = dsa_doinit(k, &dp->dp, dp->y, hc, group_prime, "prime");
 469   kcdsa_privkey(ds, dp->x);
 470   kcdsa_sethash(ds, hc);
 471   return (&ds->s);
 472 }
 473
 474 static sig *binkcdsa_siginit(key *k, void *kd, const gchash *hc)
 475 {
 476   dh_priv *dp = kd;
 477   dsa_sigctx *ds = dsa_doinit(k, &dp->dp, dp->y, hc, group_binary, "binary");
 478   kcdsa_privkey(ds, dp->x);
 479   kcdsa_sethash(ds, hc);
 480   return (&ds->s);
 481 }
 482
 483 static sig *eckcdsa_siginit(key *k, void *kd, const gchash *hc)
 484 {
 485   ec_priv *ep = kd;
 486   dsa_sigctx *ds = ecdsa_doinit(k, ep->cstr, &ep->p, hc);
 487   kcdsa_privkey(ds, ep->x);
 488   kcdsa_sethash(ds, hc);
 489   return (&ds->s);
 490 }
 491
 492 static int kcdsa_sigdoit(sig *s, dstr *d)
 493 {
 494   dsa_sigctx *ds = (dsa_sigctx *)s;
 495   gkcdsa_sig ss = GKCDSA_SIG_INIT;
 496   size_t hsz = ds->g.h->hashsz, n = mp_octets(ds->g.g->r);
 497
 498   gkcdsa_sign(&ds->g, &ss, GH_DONE(ds->s.h, 0), 0);
 499   dstr_ensure(d, hsz + n);
 500   memcpy(d->buf, ss.r, hsz);
 501   mp_storeb(ss.s, d->buf + hsz, n);
 502   d->len += hsz + n;
 503   xfree(ss.r); mp_drop(ss.s);
 504   return (0);
 505 }
 506
 507 static const sigops kcdsa_sig = {
 508   dh_privfetch, sizeof(dh_priv),
 509   kcdsa_siginit, kcdsa_sigdoit, dsa_sigcheck, dsa_sigdestroy
 510 };
 511
 512 static const sigops binkcdsa_sig = {
 513   dh_privfetch, sizeof(dh_priv),
 514   binkcdsa_siginit, kcdsa_sigdoit, dsa_sigcheck, dsa_sigdestroy
 515 };
 516
 517 static const sigops eckcdsa_sig = {
 518   ec_privfetch, sizeof(ec_priv),
 519   eckcdsa_siginit, kcdsa_sigdoit, dsa_sigcheck, dsa_sigdestroy
 520 };
 521
 522 static sig *kcdsa_vrfinit(key *k, void *kd, const gchash *hc)
 523 {
 524   dh_pub *dp = kd;
 525   dsa_sigctx *ds = dsa_doinit(k, &dp->dp, dp->y, hc, group_prime, "prime");
 526   kcdsa_sethash(ds, hc);
 527   return (&ds->s);
 528 }
 529
 530 static sig *binkcdsa_vrfinit(key *k, void *kd, const gchash *hc)
 531 {
 532   dh_pub *dp = kd;
 533   dsa_sigctx *ds = dsa_doinit(k, &dp->dp, dp->y, hc, group_binary, "binary");
 534   kcdsa_sethash(ds, hc);
 535   return (&ds->s);
 536 }
 537
 538 static sig *eckcdsa_vrfinit(key *k, void *kd, const gchash *hc)
 539 {
 540   ec_pub *ep = kd;
 541   dsa_sigctx *ds = ecdsa_doinit(k, ep->cstr, &ep->p, hc);
 542   kcdsa_sethash(ds, hc);
 543   return (&ds->s);
 544 }
 545
 546 static int kcdsa_vrfdoit(sig *s, dstr *d)
 547 {
 548   dsa_sigctx *ds = (dsa_sigctx *)s;
 549   gkcdsa_sig ss;
 550   size_t hsz = ds->g.h->hashsz, n = d->len - hsz;
 551   int rc;
 552
 553   if (d->len < hsz)
 554     return (-1);
 555   ss.r = (octet *)d->buf;
 556   ss.s = mp_loadb(MP_NEW, d->buf + hsz, n);
 557   rc = gkcdsa_verify(&ds->g, &ss, GH_DONE(ds->s.h, 0));
 558   mp_drop(ss.s);
 559   return (rc);
 560 }
 561
 562 static const sigops kcdsa_vrf = {
 563   dh_pubfetch, sizeof(dh_pub),
 564   kcdsa_vrfinit, kcdsa_vrfdoit, dsa_sigcheck, dsa_sigdestroy
 565 };
 566
 567 static const sigops binkcdsa_vrf = {
 568   dh_pubfetch, sizeof(dh_pub),
 569   binkcdsa_vrfinit, kcdsa_vrfdoit, dsa_sigcheck, dsa_sigdestroy
 570 };
 571
 572 static const sigops eckcdsa_vrf = {
 573   ec_pubfetch, sizeof(ec_pub),
 574   eckcdsa_vrfinit, kcdsa_vrfdoit, dsa_sigcheck, dsa_sigdestroy
 575 };
 576
 577 /* --- Ed25519 --- */
 578
 579 static sig *ed25519_siginit(key *k, void *kd, const gchash *hc)
 580   { sig *s = CREATE(sig); s->h = 0; return (s); }
 581
 582 static int ed25519_sigdoit(sig *s, dstr *d)
 583 {
 584   ed25519_priv *k = s->kd;
 585
 586   dstr_ensure(d, ED25519_SIGSZ);
 587   ed25519_sign((octet *)d->buf, k->priv.k, k->priv.sz, k->pub.k,
 588                GH_DONE(s->h, 0), GH_CLASS(s->h)->hashsz);
 589   d->len += ED25519_SIGSZ;
 590   return (0);
 591 }
 592
 593 static const char *ed25519_sigcheck(sig *s)
 594 {
 595   ed25519_priv *k = s->kd;
 596
 597   if (k->pub.sz != ED25519_PUBSZ)
 598     return ("incorrect Ed25519 public key length");
 599   return (0);
 600 }
 601
 602 static void ed25519_sigdestroy(sig *s) { DESTROY(s); }
 603
 604 static const sigops ed25519_sig = {
 605   ed25519_privfetch, sizeof(ed25519_priv),
 606   ed25519_siginit, ed25519_sigdoit, ed25519_sigcheck, ed25519_sigdestroy
 607 };
 608
 609 static int ed25519_vrfdoit(sig *s, dstr *d)
 610 {
 611   ed25519_pub *k = s->kd;
 612
 613   if (d->len != ED25519_SIGSZ) return (-1);
 614   return (ed25519_verify(k->pub.k, GH_DONE(s->h, 0), GH_CLASS(s->h)->hashsz,
 615                          (const octet *)d->buf));
 616 }
 617
 618 static const char *ed25519_vrfcheck(sig *s)
 619 {
 620   ed25519_pub *k = s->kd;
 621
 622   if (k->pub.sz != ED25519_PUBSZ)
 623     return ("incorrect Ed25519 public key length");
 624   return (0);
 625 }
 626
 627 static const sigops ed25519_vrf = {
 628   ed25519_pubfetch, sizeof(ed25519_pub),
 629   ed25519_siginit, ed25519_vrfdoit, ed25519_vrfcheck, ed25519_sigdestroy
 630 };
 631
 632 /* --- Symmetric message authentication --- */
 633
 634 typedef struct mac_ctx {
 635   sig s;
 636   const gcmac *mc;
 637   gmac *m;
 638   key_packdef kp;
 639   key_bin kb;
 640 } mac_ctx;
 641
 642 static sig *mac_init(key *k, void *kd, const gchash *hc)
 643 {
 644   mac_ctx *m;
 645   dstr d = DSTR_INIT;
 646   int err;
 647   const char *mm;
 648
 649   m = CREATE(mac_ctx);
 650
 651   key_fulltag(k, &d);
 652   m->kp.e = KENC_BINARY;
 653   m->kp.p = &m->kb;
 654   m->kp.kd = 0;
 655
 656   if ((mm = key_getattr(0 /*yik*/, k, "mac")) == 0) {
 657     dstr_putf(&d, "%s-hmac", hc->name);
 658     mm = d.buf;
 659   }
 660   if ((m->mc = gmac_byname(mm)) == 0)
 661     die(EXIT_FAILURE, "unknown message authentication scheme `%s'", mm);
 662   dstr_reset(&d);
 663
 664   if ((err = key_unpack(&m->kp, kd, &d)) != 0) {
 665     die(EXIT_FAILURE, "failed to unpack symmetric key `%s': %s",
 666         d.buf, key_strerror(err));
 667   }
 668   dstr_destroy(&d);
 669
 670   if (keysz(m->kb.sz, m->mc->keysz) != m->kb.sz) {
 671     die(EXIT_FAILURE, "bad key size %lu for `%s'",
 672         (unsigned long)m->kb.sz, m->mc->name);
 673   }
 674   m->m = GM_KEY(m->mc, m->kb.k, m->kb.sz);
 675   m->s.h = GM_INIT(m->m);
 676   return (&m->s);
 677 }
 678
 679 static int mac_sigdoit(sig *s, dstr *d)
 680 {
 681   mac_ctx *m = (mac_ctx *)s;
 682
 683   dstr_ensure(d, m->mc->hashsz);
 684   GH_DONE(m->s.h, d->buf);
 685   d->len += m->mc->hashsz;
 686   return (0);
 687 }
 688
 689 static int mac_vrfdoit(sig *s, dstr *d)
 690 {
 691   mac_ctx *m = (mac_ctx *)s;
 692   const octet *t;
 693
 694   t = GH_DONE(m->s.h, 0);
 695   if (d->len != m->mc->hashsz || !ct_memeq(d->buf, t, d->len))
 696     return (-1);
 697   return (0);
 698 }
 699
 700 static const char *mac_check(sig *s) { return (0); }
 701
 702 static void mac_destroy(sig *s)
 703 {
 704   mac_ctx *m = (mac_ctx *)s;
 705   GM_DESTROY(m->m);
 706   key_unpackdone(&m->kp);
 707 }
 708
 709 static const sigops mac_sig = {
 710   0, 0,
 711   mac_init, mac_sigdoit, mac_check, mac_destroy
 712 };
 713
 714 static const sigops mac_vrf = {
 715   0, 0,
 716   mac_init, mac_vrfdoit, mac_check, mac_destroy
 717 };
 718
 719 /* --- The switch table --- */
 720
 721 const struct sigtab sigtab[] = {
 722   { "rsapkcs1", &rsap1_sig,     &rsap1_vrf,     &sha },
 723   { "rsapss",   &rsapss_sig,    &rsapss_vrf,    &sha },
 724   { "dsa",      &dsa_sig,       &dsa_vrf,       &sha },
 725   { "bindsa",   &bindsa_sig,    &bindsa_vrf,    &sha },
 726   { "ecdsa",    &ecdsa_sig,     &ecdsa_vrf,     &sha },
 727   { "kcdsa",    &kcdsa_sig,     &kcdsa_vrf,     &has160 },
 728   { "binkcdsa", &binkcdsa_sig,  &binkcdsa_vrf,  &has160 },
 729   { "eckcdsa",  &eckcdsa_sig,   &eckcdsa_vrf,   &has160 },
 730   { "ed25519",  &ed25519_sig,   &ed25519_vrf,   &sha512 },
 731   { "mac",      &mac_sig,       &mac_vrf,       &rmd160 },
 732   { 0,          0,              0 }
 733 };
 734
 735 /* --- @getsig@ --- *
 736  *
 737  * Arguments:   @key *k@ = the key to load
 738  *              @const char *app@ = application name
 739  *              @int wantpriv@ = nonzero if we want to sign
 740  *
 741  * Returns:     A signature-making thing.
 742  *
 743  * Use:         Loads a key and starts hashing.
 744  */
 745
 746 sig *getsig(key *k, const char *app, int wantpriv)
 747 {
 748   const char *salg, *halg = 0;
 749   dstr d = DSTR_INIT;
 750   dstr t = DSTR_INIT;
 751   char *p = 0;
 752   const char *q;
 753   sig *s;
 754   size_t n;
 755   const struct sigtab *st;
 756   const sigops *so;
 757   const gchash *ch;
 758   void *kd;
 759   int e;
 760   key_packdef *kp;
 761
 762   /* --- Setup stuff --- */
 763
 764   key_fulltag(k, &t);
 765
 766   /* --- Get the signature algorithm --- *
 767    *
 768    * Take the attribute if it's there; otherwise use the key type.
 769    */
 770
 771   n = strlen(app);
 772   if ((q = key_getattr(0, k, "sig")) != 0) {
 773     dstr_puts(&d, q);
 774     p = d.buf;
 775   } else if (strncmp(k->type, app, n) == 0 && k->type[n] == '-') {
 776     dstr_puts(&d, k->type);
 777     p = d.buf + n + 1;
 778   } else
 779     die(EXIT_FAILURE, "no signature algorithm for key `%s'", t.buf);
 780
 781   /* --- Grab the hash algorithm --- *
 782    *
 783    * Grab it from the signature algorithm if it's there.  But override that
 784    * from the attribute.
 785    */
 786
 787   salg = p;
 788   if ((p = strchr(p, '/')) != 0) {
 789     *p++ = 0;
 790     halg = p;
 791   }
 792   if ((q = key_getattr(0, k, "hash")) != 0)
 793     halg = q;
 794
 795   /* --- Look up the algorithms in the table --- */
 796
 797   for (st = sigtab; st->name; st++) {
 798     if (strcmp(st->name, salg) == 0)
 799       goto s_found;
 800   }
 801   die(EXIT_FAILURE, "signature algorithm `%s' not found in key `%s'",
 802       salg, t.buf);
 803 s_found:;
 804   if (!halg)
 805     ch = st->ch;
 806   else {
 807     if ((ch = ghash_byname(halg)) == 0) {
 808       die(EXIT_FAILURE, "hash algorithm `%s' not found in key `%s'",
 809           halg, t.buf);
 810     }
 811   }
 812   so = wantpriv ? st->signops : st->verifyops;
 813
 814   /* --- Load the key --- */
 815
 816   if (!so->kf) {
 817     kd = k->k;
 818     key_incref(kd);
 819     kp = 0;
 820   } else {
 821     kd = xmalloc(so->kdsz);
 822     kp = key_fetchinit(so->kf, 0, kd);
 823     if ((e = key_fetch(kp, k)) != 0) {
 824       die(EXIT_FAILURE, "error fetching key `%s': %s",
 825           t.buf, key_strerror(e));
 826     }
 827   }
 828   s = so->init(k, kd, ch);
 829   if (!s->h)
 830     s->h = GH_INIT(ch);
 831   s->kp = kp;
 832   s->ops = so;
 833   s->kd = kd;
 834   s->ch = ch;
 835
 836   /* --- Free stuff up --- */
 837
 838   dstr_destroy(&d);
 839   dstr_destroy(&t);
 840   return (s);
 841 }
 842
 843 /* --- @freesig@ --- *
 844  *
 845  * Arguments:   @sig *s@ = signature-making thing
 846  *
 847  * Returns:     ---
 848  *
 849  * Use:         Frees up a signature-making thing
 850  */
 851
 852 void freesig(sig *s)
 853 {
 854   GH_DESTROY(s->h);
 855   if (!s->ops->kf)
 856     key_drop(s->kd);
 857   else {
 858     key_fetchdone(s->kp);
 859     xfree(s->kd);
 860   }
 861   s->ops->destroy(s);
 862 }
 863
 864 /*----- That's all, folks -------------------------------------------------*/