mdw@git.distorted.org.uk Git - tripe/blob - server/keymgmt.c

   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 /*----- Global variables --------------------------------------------------*/
  32
  33 group *gg;
  34 mp *kpriv;
  35 ge *kpub;
  36 algswitch algs;
  37 size_t indexsz;
  38
  39 /*----- Static variables --------------------------------------------------*/
  40
  41 static key_file *kf_pub;
  42 static const char *kr_priv, *kr_pub, *tag_priv;
  43 static fwatch w_priv, w_pub;
  44
  45 /*----- Key groups --------------------------------------------------------*/
  46
  47 typedef struct kgops {
  48   const char *ty;
  49   int (*loadpriv)(key_data *, group **, mp **, dstr *, dstr *);
  50   int (*loadpub)(key_data *, group **, ge **, dstr *, dstr *);
  51 } kgops;
  52
  53 /* --- Diffie-Hellman --- */
  54
  55 static int kgdh_priv(key_data *kd, group **g, mp **x, dstr *t, dstr *e)
  56 {
  57   key_packstruct kps[DH_PRIVFETCHSZ];
  58   key_packdef *kp;
  59   dh_priv dp;
  60   int rc;
  61
  62   kp = key_fetchinit(dh_privfetch, kps, &dp);
  63   if ((rc = key_unpack(kp, kd, t)) != 0) {
  64     a_format(e, "unpack-failed", "%s", key_strerror(rc), A_END);
  65     goto fail_0;
  66   }
  67   *g = group_prime(&dp.dp);
  68   *x = MP_COPY(dp.x);
  69   rc = 0;
  70   goto done;
  71 fail_0:
  72   rc = -1;
  73 done:
  74   key_fetchdone(kp);
  75   return (rc);
  76 }
  77
  78 static int kgdh_pub(key_data *kd, group **g, ge **p, dstr *t, dstr *e)
  79 {
  80   key_packstruct kps[DH_PUBFETCHSZ];
  81   key_packdef *kp;
  82   dh_pub dp;
  83   int rc;
  84
  85   kp = key_fetchinit(dh_pubfetch, kps, &dp);
  86   if ((rc = key_unpack(kp, kd, t)) != 0) {
  87     a_format(e, "unpack-failed", "%s", key_strerror(rc), A_END);
  88     goto fail_0;
  89   }
  90   *g = group_prime(&dp.dp);
  91   *p = G_CREATE(*g);
  92   if (G_FROMINT(*g, *p, dp.y)) {
  93     a_format(e, "bad-public-vector", A_END);
  94     goto fail_1;
  95   }
  96   rc = 0;
  97   goto done;
  98 fail_1:
  99   G_DESTROY(*g, *p);
 100   G_DESTROYGROUP(*g);
 101 fail_0:
 102   rc = -1;
 103 done:
 104   key_fetchdone(kp);
 105   return (rc);
 106 }
 107
 108 static const kgops kgdh_ops = { "dh", kgdh_priv, kgdh_pub };
 109
 110 /* --- Elliptic curve --- */
 111
 112 static int kgec_priv(key_data *kd, group **g, mp **x, dstr *t, dstr *e)
 113 {
 114   key_packstruct kps[EC_PRIVFETCHSZ];
 115   key_packdef *kp;
 116   ec_priv ep;
 117   ec_info ei;
 118   const char *err;
 119   int rc;
 120
 121   kp = key_fetchinit(ec_privfetch, kps, &ep);
 122   if ((rc = key_unpack(kp, kd, t)) != 0) {
 123     a_format(e, "unpack-failed", "%s", key_strerror(rc), A_END);
 124     goto fail_0;
 125   }
 126   if ((err = ec_getinfo(&ei, ep.cstr)) != 0) {
 127     a_format(e, "decode-failed", "%s", err, A_END);
 128     goto fail_0;
 129   }
 130   *g = group_ec(&ei);
 131   *x = MP_COPY(ep.x);
 132   rc = 0;
 133   goto done;
 134 fail_0:
 135   rc = -1;
 136 done:
 137   key_fetchdone(kp);
 138   return (rc);
 139 }
 140
 141 static int kgec_pub(key_data *kd, group **g, ge **p, dstr *t, dstr *e)
 142 {
 143   key_packstruct kps[EC_PUBFETCHSZ];
 144   key_packdef *kp;
 145   ec_pub ep;
 146   ec_info ei;
 147   const char *err;
 148   int rc;
 149
 150   kp = key_fetchinit(ec_pubfetch, kps, &ep);
 151   if ((rc = key_unpack(kp, kd, t)) != 0) {
 152     a_format(e, "unpack-failed", "%s", key_strerror(rc), A_END);
 153     goto fail_0;
 154   }
 155   if ((err = ec_getinfo(&ei, ep.cstr)) != 0) {
 156     a_format(e, "decode-failed", "%s", err, A_END);
 157     goto fail_0;
 158   }
 159   *g = group_ec(&ei);
 160   *p = G_CREATE(*g);
 161   if (G_FROMEC(*g, *p, &ep.p)) {
 162     a_format(e, "bad-public-vector", A_END);
 163     goto fail_1;
 164   }
 165   rc = 0;
 166   goto done;
 167 fail_1:
 168   G_DESTROY(*g, *p);
 169   G_DESTROYGROUP(*g);
 170 fail_0:
 171   rc = -1;
 172 done:
 173   key_fetchdone(kp);
 174   return (rc);
 175 }
 176
 177 static const kgops kgec_ops = { "ec", kgec_priv, kgec_pub };
 178
 179 /* --- Table of supported key types --- */
 180
 181 static const kgops *kgtab[] = { &kgdh_ops, &kgec_ops, 0 };
 182
 183 /*----- Algswitch stuff ---------------------------------------------------*/
 184
 185 /* --- @algs_get@ --- *
 186  *
 187  * Arguments:   @algswitch *a@ = where to put the algorithms
 188  *              @dstr *e@ = where to write errror tokens
 189  *              @key_file *kf@ = key file
 190  *              @key *k@ = key to inspect
 191  *
 192  * Returns:     Zero if OK; nonzero on error.
 193  *
 194  * Use:         Extracts an algorithm choice from a key.
 195  */
 196
 197 static int algs_get(algswitch *a, dstr *e, key_file *kf, key *k)
 198 {
 199   const char *p;
 200   char *q, *qq;
 201   dstr d = DSTR_INIT;
 202   int rc = -1;
 203
 204   /* --- Symmetric encryption for bulk data --- */
 205
 206   if ((p = key_getattr(kf, k, "cipher")) == 0) p = "blowfish-cbc";
 207   if ((a->c = gcipher_byname(p)) == 0) {
 208     a_format(e, "unknown-cipher", "%s", p, A_END);
 209     goto done;
 210   }
 211
 212   /* --- Hash function --- */
 213
 214   if ((p = key_getattr(kf, k, "hash")) == 0) p = "rmd160";
 215   if ((a->h = ghash_byname(p)) == 0) {
 216     a_format(e, "unknown-hash", "%s", p, A_END);
 217     goto done;
 218   }
 219
 220   /* --- Symmetric encryption for key derivation --- */
 221
 222   if ((p = key_getattr(kf, k, "mgf")) == 0) {
 223     dstr_reset(&d);
 224     dstr_putf(&d, "%s-mgf", a->h->name);
 225     p = d.buf;
 226   }
 227   if ((a->mgf = gcipher_byname(p)) == 0) {
 228     a_format(e, "unknown-mgf-cipher", "%s", p, A_END);
 229     goto done;
 230   }
 231
 232   /* --- Message authentication for bulk data --- */
 233
 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   rc = 0;
 268 done:
 269   dstr_destroy(&d);
 270   return (rc);
 271 }
 272
 273 /* --- @algs_check@ --- *
 274  *
 275  * Arguments:   @algswitch *a@ = a choice of algorithms
 276  *              @dstr *e@ = where to write error tokens
 277  *              @const group *g@ = the group we're working in
 278  *
 279  * Returns:     Zero if OK; nonzero on error.
 280  *
 281  * Use:         Checks an algorithm choice for sensibleness.  This also
 282  *              derives some useful information from the choices, and you
 283  *              must call this before committing the algorithm selection
 284  *              for use by @keyset@ functions.
 285  */
 286
 287 static int algs_check(algswitch *a, dstr *e, const group *g)
 288 {
 289   /* --- Derive the key sizes --- *
 290    *
 291    * Must ensure that we have non-empty keys.  This isn't ideal, but it
 292    * provides a handy sanity check.  Also must be based on a 64- or 128-bit
 293    * block cipher or we can't do the data expiry properly.
 294    */
 295
 296   a->hashsz = a->h->hashsz;
 297   if ((a->cksz = keysz(a->hashsz, a->c->keysz)) == 0) {
 298     a_format(e, "cipher", "%s", a->c->name,
 299              "no-key-size", "%lu", (unsigned long)a->hashsz,
 300              A_END);
 301     return (-1);
 302   }
 303   if ((a->mksz = keysz(a->hashsz, a->m->keysz)) == 0) {
 304     a_format(e, "mac", "%s", a->m->name,
 305              "no-key-size", "%lu", (unsigned long)a->hashsz,
 306              A_END);
 307     return (-1);
 308   }
 309
 310   /* --- Derive the data limit --- */
 311
 312   if (a->c->blksz < 16) a->expsz = MEG(64);
 313   else a->expsz = MEG(2048);
 314
 315   /* --- Ensure the MGF accepts hashes as keys --- */
 316
 317   if (keysz(a->hashsz, a->mgf->keysz) != a->hashsz) {
 318     a_format(e, "mgf", "%s", a->mgf->name,
 319              "restrictive-key-schedule",
 320              A_END);
 321     return (-1);
 322   }
 323
 324   /* --- All ship-shape and Bristol-fashion --- */
 325
 326   return (0);
 327 }
 328
 329 /* --- @algs_samep@ --- *
 330  *
 331  * Arguments:   @const algswitch *a, *aa@ = two algorithm selections
 332  *
 333  * Returns:     Nonzero if the two selections are the same.
 334  *
 335  * Use:         Checks sameness of algorithm selections: used to ensure that
 336  *              peers are using sensible algorithms.
 337  */
 338
 339 static int algs_samep(const algswitch *a, const algswitch *aa)
 340 {
 341   return (a->c == aa->c && a->mgf == aa->mgf && a->h == aa->h &&
 342           a->m == aa->m && a->tagsz == aa->tagsz);
 343 }
 344
 345 /*----- Main code ---------------------------------------------------------*/
 346
 347 /* --- @keymoan@ --- *
 348  *
 349  * Arguments:   @const char *file@ = name of the file
 350  *              @int line@ = line number in file
 351  *              @const char *msg@ = error message
 352  *              @void *p@ = argument pointer (indicates which keyring)
 353  *
 354  * Returns:     ---
 355  *
 356  * Use:         Reports an error message about loading a key file.
 357  */
 358
 359 static void keymoan(const char *file, int line, const char *msg, void *p)
 360 {
 361   const char *kind = p;
 362
 363   if (!line) {
 364     a_warn("KEYMGMT", "%s-keyring", kind, "%s", file,
 365            "io-error", "?ERRNO", A_END);
 366   } else {
 367     a_warn("KEYMGMT", "%s-keyring", kind, "%s", file, "line", "%d", line,
 368            "%s", msg, A_END);
 369   }
 370 }
 371
 372 /* --- @keykg@ --- *
 373  *
 374  * Arguments:   @key_file *kf@ = pointer to key file
 375  *              @key *k@ = pointer to key
 376  *              @const char **tyr@ = where to put the type string
 377  *
 378  * Returns:     Pointer to indicated key-group options, or null.
 379  *
 380  * Use:         Looks up a key's group indicator and tries to find a matching
 381  *              table entry.
 382  */
 383
 384 static const kgops *keykg(key_file *kf, key *k, const char **tyr)
 385 {
 386   const char *ty;
 387   const kgops **ko;
 388
 389   /* --- Look up the key type in the table --- *
 390    *
 391    * There are several places to look for this.  The most obvious is the
 392    * `kx-group' key attribute.  But there's also the key type itself.
 393    */
 394
 395   ty = key_getattr(kf, k, "kx-group");
 396   if (!ty && strncmp(k->type, "tripe-", 6) == 0) ty = k->type + 6;
 397   if (!ty) ty = "dh";
 398   if (tyr) *tyr = ty;
 399
 400   for (ko = kgtab; *ko; ko++) {
 401     if (strcmp((*ko)->ty, ty) == 0)
 402       return (*ko);
 403   }
 404   return (0);
 405 }
 406
 407 /* --- @loadpriv@ --- *
 408  *
 409  * Arguments:   @dstr *d@ = string to write errors in
 410  *
 411  * Returns:     Zero if OK, nonzero on error.
 412  *
 413  * Use:         Loads the private key from its keyfile.
 414  */
 415
 416 static int loadpriv(void)
 417 {
 418   key_file kf;
 419   key *k;
 420   key_data **kd;
 421   dstr t = DSTR_INIT;
 422   dstr e = DSTR_INIT;
 423   group *g = 0;
 424   mp *x = 0;
 425   int rc = -1;
 426   const kgops *ko;
 427   const char *err, *tag, *ty;
 428   algswitch a;
 429
 430   /* --- Open the private key file --- */
 431
 432   if (key_open(&kf, kr_priv, KOPEN_READ, keymoan, "private"))
 433     goto done_0;
 434
 435   /* --- Find the private key --- */
 436
 437   if (tag_priv ?
 438       key_qtag(&kf, tag = tag_priv, &t, &k, &kd) :
 439       key_qtag(&kf, tag = "tripe", &t, &k, &kd) &&
 440         key_qtag(&kf, tag = "tripe-dh", &t, &k, &kd)) {
 441     a_warn("KEYMGMT", "private-keyring", "%s", kr_priv,
 442            "key-not-found", "%s", tag, A_END);
 443     goto done_1;
 444   }
 445
 446   /* --- Look up the key type in the table --- */
 447
 448   if ((ko = keykg(&kf, k, &ty)) == 0) {
 449     a_warn("KEYMGMT", "private-keyring",
 450            "%s", kr_priv, "key", "%s", t.buf,
 451            "unknown-group-type", "%s", ty, A_END);
 452     goto done_1;
 453   }
 454
 455   /* --- Load the key --- */
 456
 457   if (ko->loadpriv(*kd, &g, &x, &t, &e)) {
 458     a_warn("KEYMGMT", "private-keyring",
 459            "%s", kr_priv, "key", "%s", t.buf,
 460            "*%s", e.buf, A_END);
 461     goto done_1;
 462   }
 463
 464   /* --- Check that the key is sensible --- */
 465
 466   if ((err = G_CHECK(g, &rand_global)) != 0) {
 467     a_warn("KEYMGMT", "private-keyring",
 468            "%s", kr_priv, "key", "%s", t.buf,
 469            "bad-group", "%s", err, A_END);
 470     goto done_1;
 471   }
 472
 473   /* --- Collect the algorithms --- */
 474
 475   if (algs_get(&a, &e, &kf, k) ||
 476       algs_check(&a, &e, g)) {
 477     a_warn("KEYMGMT", "private-keyring",
 478            "%s", kr_priv, "key", "%s", t.buf,
 479            "*%s", e.buf, A_END);
 480     goto done_1;
 481   }
 482
 483   /* --- Good, we're happy --- *
 484    *
 485    * Dodginess!  We change the group over here, but don't free any old group
 486    * elements.  This assumes that the new group is basically the same as the
 487    * old one, and will happily adopt the existing elements.  If it isn't,
 488    * then we lose badly.  Check this, then.
 489    */
 490
 491   if (gg) {
 492     if (!group_samep(g, gg)) {
 493       a_warn("KEYMGMT", "private-keyring",
 494              "%s", kr_priv, "key", "%s", t.buf,
 495              "changed-group", A_END);
 496       goto done_1;
 497     }
 498     G_DESTROYGROUP(gg);
 499   }
 500   if (kpriv)
 501     mp_drop(kpriv);
 502
 503   if (kpub)
 504     G_DESTROY(g, kpub);
 505   kpub = G_CREATE(g);
 506   G_EXP(g, kpub, g->g, x);
 507   indexsz = mp_octets(g->r);
 508
 509   /* --- Dump out the group --- */
 510
 511   IF_TRACING(T_KEYMGMT, {
 512     trace(T_KEYMGMT, "keymgmt: extracted private key `%s'", t.buf);
 513     IF_TRACING(T_CRYPTO, {
 514       trace(T_CRYPTO, "crypto: r = %s", mpstr(g->r));
 515       trace(T_CRYPTO, "crypto: h = %s", mpstr(g->h));
 516       trace(T_CRYPTO, "crypto: x = %s", mpstr(x));
 517       trace(T_CRYPTO, "crypto: cipher = %s", a.c->name);
 518       trace(T_CRYPTO, "crypto: mgf = %s", a.mgf->name);
 519       trace(T_CRYPTO, "crypto: hash = %s", a.h->name);
 520       trace(T_CRYPTO, "crypto: mac = %s/%lu",
 521             a.m->name, (unsigned long)a.tagsz * 8);
 522     })
 523   })
 524
 525   /* --- Success! --- */
 526
 527   gg = g; g = 0;
 528   algs = a;
 529   kpriv = x; x = 0;
 530   rc = 0;
 531
 532   /* --- Tidy up --- */
 533
 534 done_1:
 535   key_close(&kf);
 536 done_0:
 537   dstr_destroy(&t);
 538   dstr_destroy(&e);
 539   if (x) mp_drop(x);
 540   if (g) G_DESTROYGROUP(g);
 541   return (rc);
 542 }
 543
 544 /* --- @loadpub@ --- *
 545  *
 546  * Arguments:   @dstr *d@ = string to write errors to
 547  *
 548  * Returns:     Zero if OK, nonzero on error.
 549  *
 550  * Use:         Reloads the public keyring.
 551  */
 552
 553 static int loadpub(void)
 554 {
 555   key_file *kf = CREATE(key_file);
 556
 557   if (key_open(kf, kr_pub, KOPEN_READ, keymoan, "public")) {
 558     DESTROY(kf);
 559     return (-1);
 560   }
 561   kf_pub = kf;
 562   T( trace(T_KEYMGMT, "keymgmt: loaded public keyring `%s'", kr_pub); )
 563   return (0);
 564 }
 565
 566 /* --- @km_reload@ --- *
 567  *
 568  * Arguments:   ---
 569  *
 570  * Returns:     Zero if OK, nonzero to force reloading of keys.
 571  *
 572  * Use:         Checks the keyrings to see if they need reloading.
 573  */
 574
 575 int km_reload(void)
 576 {
 577   key_file *kf;
 578   int reload = 0;
 579
 580   /* --- Check the private key first --- */
 581
 582   if (fwatch_update(&w_priv, kr_priv)) {
 583     T( trace(T_KEYMGMT, "keymgmt: private keyring updated: reloading..."); )
 584     if (!loadpriv())
 585       reload = 1;
 586   }
 587
 588   /* --- Now check the public keys --- */
 589
 590   if (fwatch_update(&w_pub, kr_pub)) {
 591     T( trace(T_KEYMGMT, "keymgmt: public keyring updated: reloading..."); )
 592     kf = kf_pub;
 593     if (!loadpub()) {
 594       reload = 1;
 595       key_close(kf);
 596       DESTROY(kf);
 597     }
 598   }
 599
 600   /* --- Done --- */
 601
 602   return (reload);
 603 }
 604
 605 /* --- @km_init@ --- *
 606  *
 607  * Arguments:   @const char *priv@ = private keyring file
 608  *              @const char *pub@ = public keyring file
 609  *              @const char *tag@ = tag to load
 610  *
 611  * Returns:     ---
 612  *
 613  * Use:         Initializes, and loads the private key.
 614  */
 615
 616 void km_init(const char *priv, const char *pub, const char *tag)
 617 {
 618   const gchash *const *hh;
 619
 620   kr_priv = priv;
 621   kr_pub = pub;
 622   tag_priv = tag;
 623   fwatch_init(&w_priv, kr_priv);
 624   fwatch_init(&w_pub, kr_pub);
 625
 626   for (hh = ghashtab; *hh; hh++) {
 627     if ((*hh)->hashsz > MAXHASHSZ) {
 628       die(EXIT_FAILURE, "INTERNAL ERROR: %s hash length %lu > MAXHASHSZ %d",
 629           (*hh)->name, (unsigned long)(*hh)->hashsz, MAXHASHSZ);
 630     }
 631   }
 632
 633   if (loadpriv() || loadpub())
 634     exit(EXIT_FAILURE);
 635 }
 636
 637 /* --- @km_getpubkey@ --- *
 638  *
 639  * Arguments:   @const char *tag@ = public key tag to load
 640  *              @ge *kpub@ = where to put the public key
 641  *              @time_t *t_exp@ = where to put the expiry time
 642  *
 643  * Returns:     Zero if OK, nonzero if it failed.
 644  *
 645  * Use:         Fetches a public key from the keyring.
 646  */
 647
 648 int km_getpubkey(const char *tag, ge *kpub, time_t *t_exp)
 649 {
 650   key *k;
 651   key_data **kd;
 652   dstr t = DSTR_INIT;
 653   dstr e = DSTR_INIT;
 654   const kgops *ko;
 655   const char *ty;
 656   group *g = 0;
 657   ge *p = 0;
 658   algswitch a;
 659   int rc = -1;
 660
 661   /* --- Find the key --- */
 662
 663   if (key_qtag(kf_pub, tag, &t, &k, &kd)) {
 664     a_warn("KEYMGMT", "public-keyring", "%s", kr_pub,
 665            "key-not-found", "%s", tag, A_END);
 666     goto done;
 667   }
 668
 669   /* --- Look up the key type in the table --- */
 670
 671   if ((ko = keykg(kf_pub, k, &ty)) == 0) {
 672     a_warn("KEYMGMT", "public-keyring",
 673            "%s", kr_pub, "key", "%s", t.buf,
 674            "unknown-group-type", "%s", ty, A_END);
 675     goto done;
 676   }
 677
 678   /* --- Load the key --- */
 679
 680   if (ko->loadpub(*kd, &g, &p, &t, &e)) {
 681     a_warn("KEYMGMT", "public-keyring",
 682            "%s", kr_pub, "key", "%s", t.buf,
 683            "*%s", e.buf, A_END);
 684     goto done;
 685   }
 686
 687   /* --- Ensure that the group is correct --- *
 688    *
 689    * Dodginess!  We assume that if this works, our global group is willing to
 690    * adopt this public element.  Probably reasonable.
 691    */
 692
 693   if (!group_samep(gg, g)) {
 694     a_warn("KEYMGMT", "public-keyring",
 695            "%s", kr_pub, "key", "%s", t.buf,
 696            "*%s", e.buf, A_END);
 697     goto done;
 698   }
 699
 700   /* --- Check the public group element --- */
 701
 702   if (group_check(gg, p)) {
 703     a_warn("KEYMGMT", "public-keyring",
 704            "%s", kr_pub, "key", "%s", t.buf,
 705            "bad-public-group-element",
 706            A_END);
 707     goto done;
 708   }
 709
 710   /* --- Check the algorithms --- */
 711
 712   if (algs_get(&a, &e, kf_pub, k)) {
 713     a_warn("KEYMGMT", "public-keyring",
 714            "%s", kr_pub, "key", "%s", t.buf,
 715            "*%s", e.buf, A_END);
 716     goto done;
 717   }
 718   if (!algs_samep(&a, &algs)) {
 719     a_warn("KEYMGMT", "public-keyring",
 720            "%s", kr_pub, "key", "%s", t.buf,
 721            "algorithm-mismatch", A_END);
 722     goto done;
 723   }
 724
 725   /* --- Dump the public key --- */
 726
 727   IF_TRACING(T_KEYMGMT, {
 728     trace(T_KEYMGMT, "keymgmt: extracted public key `%s'", t.buf);
 729     trace(T_CRYPTO, "crypto: p = %s", gestr(gg, p));
 730   })
 731
 732   /* --- OK, accept the public key --- */
 733
 734   *t_exp = k->exp;
 735   G_COPY(gg, kpub, p);
 736   rc = 0;
 737
 738   /* --- Tidy up --- */
 739
 740 done:
 741   if (p) G_DESTROY(g, p);
 742   if (g) G_DESTROYGROUP(g);
 743   dstr_destroy(&t);
 744   dstr_destroy(&e);
 745   return (rc);
 746 }
 747
 748 /*----- That's all, folks -------------------------------------------------*/