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