git.distorted.org.uk Git - u/mdw/catacomb/blob - tlsprf.c

   1 /* -*-c-*-
   2  *
   3  * $Id: tlsprf.c,v 1.3 2004/04/08 01:36:15 mdw Exp $
   4  *
   5  * The TLS pseudo-random function
   6  *
   7  * (c) 2001 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb 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 Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Header files ------------------------------------------------------*/
  31
  32 #include <mLib/alloc.h>
  33 #include <mLib/dstr.h>
  34 #include <mLib/sub.h>
  35
  36 #include "arena.h"
  37 #include "gmac.h"
  38 #include "grand.h"
  39 #include "paranoia.h"
  40 #include "tlsprf.h"
  41
  42 /*----- The data expansion function ---------------------------------------*/
  43
  44 /* --- @tlsdx_init@ --- *
  45  *
  46  * Arguments:   @tlsdx_ctx *c@ = pointer to a context
  47  *              @gmac *m@ = pointer to a generic MAC instance
  48  *              @const void *sd@ = pointer to the seed block
  49  *              @size_t sdsz@ = size of the seed block
  50  *
  51  * Returns:     ---
  52  *
  53  * Use:         Initializes a context for the TLS data expansion function.
  54  *              This doesn't take ownership of the MAC instance or the seed
  55  *              memory, nor does it allocate copies.
  56  */
  57
  58 void tlsdx_init(tlsdx_ctx *c, gmac *m, const void *sd, size_t sdsz)
  59 {
  60   c->k = m;
  61   c->hashsz = GM_CLASS(c->k)->hashsz;
  62   c->sd = sd; c->sdsz = sdsz;
  63
  64   c->i = GM_INIT(c->k);
  65   GH_HASH(c->i, sd, sdsz);
  66   c->ai = GH_DONE(c->i, 0);
  67   c->o = GM_INIT(c->k);
  68   GH_HASH(c->o, c->ai, c->hashsz);
  69   GH_HASH(c->o, sd, sdsz);
  70   c->p = GH_DONE(c->o, 0);
  71   c->sz = c->hashsz;
  72 }
  73
  74 /* --- @tlsdx_encrypt@ --- *
  75  *
  76  * Arguments:   @tlsdx_ctx *c@ = pointer to a context
  77  *              @const void *src@ = pointer to source data
  78  *              @void *dest@ = pointer to destination buffer
  79  *              @size_t sz@ = size of buffer
  80  *
  81  * Returns:     ---
  82  *
  83  * Use:         Encrypts data using the TLS data expansion function.  If the
  84  *              destination pointer is null, the generator is spun and no
  85  *              output is produced; if the source pointer is null, raw output
  86  *              from the generator is written; otherwise, the source data is
  87  *              XORed with the generator output.
  88  */
  89
  90 void tlsdx_encrypt(tlsdx_ctx *c, const void *src, void *dest, size_t sz)
  91 {
  92   const octet *s = src;
  93   octet *d = dest;
  94   ghash *h;
  95   size_t i;
  96   size_t n;
  97
  98   while (sz) {
  99     if (c->sz)
 100       n = c->sz;
 101     else {
 102       h = GM_INIT(c->k);
 103       GH_HASH(h, c->ai, c->hashsz);
 104       c->ai = GH_DONE(h, 0);
 105       GH_DESTROY(c->i);
 106       c->i = h;
 107       GH_DESTROY(c->o);
 108       h = c->o = GM_INIT(c->k);
 109       GH_HASH(h, c->ai, c->hashsz);
 110       GH_HASH(h, c->sd, c->sdsz);
 111       c->p = GH_DONE(h, 0);
 112       c->sz = n = c->hashsz;
 113     }
 114     if (n > sz)
 115       n = sz;
 116     if (d) {
 117       if (!s)
 118         memcpy(d, c->p, n);
 119       else {
 120         for (i = 0; i < n; i++) d[i] = s[i] ^ c->p[i];
 121         s += n;
 122       }
 123       d += n;
 124     }
 125     c->p += n;
 126     c->sz -= n;
 127     sz -= n;
 128   }
 129 }
 130
 131 /* --- @tlsdx_free@ --- *
 132  *
 133  * Arguments:   @tlsdx_ctx *c@ = pointer to the context block
 134  *
 135  * Returns:     ---
 136  *
 137  * Use:         Frees a context for the TLS data expansion function
 138  */
 139
 140 void tlsdx_free(tlsdx_ctx *c)
 141 {
 142   GH_DESTROY(c->i);
 143   GH_DESTROY(c->o);
 144 }
 145
 146 /* --- Generic random number generator --- */
 147
 148 typedef struct dx_grctx {
 149   grand r;
 150   grand_ops ops;
 151   tlsdx_ctx dx;
 152 } dx_grctx;
 153
 154 static void dx_grdestroy(grand *r)
 155 {
 156   dx_grctx *g = (dx_grctx *)r;
 157   xfree((char *)g->ops.name);
 158   xfree((octet *)g->dx.sd);
 159   g->dx.k->ops->destroy(g->dx.k);
 160   tlsdx_free(&g->dx);
 161   BURN(*g);
 162   S_DESTROY(g);
 163 }
 164
 165 static void dx_seed(dx_grctx *g, const void *p, size_t sz)
 166 {
 167   octet *q;
 168   xfree((octet *)g->dx.sd);
 169   g->dx.sd = q = xmalloc(sz);
 170   memcpy(q, p, sz);
 171   g->dx.sdsz = sz;
 172 }
 173
 174 static int dx_grmisc(grand *r, unsigned op, ...)
 175 {
 176   dx_grctx *g = (dx_grctx *)r;
 177   va_list ap;
 178   int rc = 0;
 179   uint32 i;
 180   octet buf[4];
 181   va_start(ap, op);
 182
 183   switch (op) {
 184     case GRAND_CHECK:
 185       switch (va_arg(ap, unsigned)) {
 186         case GRAND_CHECK:
 187         case GRAND_SEEDINT:
 188         case GRAND_SEEDUINT32:
 189         case GRAND_SEEDBLOCK:
 190         case GRAND_SEEDRAND:
 191           rc = 1;
 192           break;
 193         default:
 194           rc = 0;
 195           break;
 196       }
 197       break;
 198     case GRAND_SEEDINT:
 199       i = va_arg(ap, unsigned);
 200       STORE32(buf, i);
 201       dx_seed(g, buf, sizeof(buf));
 202       break;
 203     case GRAND_SEEDUINT32:
 204       i = va_arg(ap, uint32);
 205       STORE32(buf, i);
 206       dx_seed(g, buf, sizeof(buf));
 207       break;
 208     case GRAND_SEEDBLOCK: {
 209       const void *p = va_arg(ap, const void *);
 210       size_t sz = va_arg(ap, size_t);
 211       dx_seed(g, p, sz);
 212     } break;
 213     case GRAND_SEEDRAND: {
 214       grand *rr = va_arg(ap, grand *);
 215       octet buf[16];
 216       rr->ops->fill(rr, buf, sizeof(buf));
 217       dx_seed(g, buf, sizeof(buf));
 218     } break;
 219     default:
 220       GRAND_BADOP;
 221       break;
 222   }
 223
 224   va_end(ap);
 225   return (rc);
 226 }
 227
 228 static octet dx_grbyte(grand *r)
 229 {
 230   dx_grctx *g = (dx_grctx *)r;
 231   octet o;
 232   tlsdx_encrypt(&g->dx, 0, &o, 1);
 233   return (o);
 234 }
 235
 236 static uint32 dx_grword(grand *r)
 237 {
 238   dx_grctx *g = (dx_grctx *)r;
 239   octet b[4];
 240   tlsdx_encrypt(&g->dx, 0, &b, sizeof(b));
 241   return (LOAD32(b));
 242 }
 243
 244 static void dx_grfill(grand *r, void *p, size_t sz)
 245 {
 246   dx_grctx *g = (dx_grctx *)r;
 247   tlsdx_encrypt(&g->dx, 0, p, sz);
 248 }
 249
 250 static const grand_ops dx_grops = {
 251   "<tlsdx-dummy>",
 252   GRAND_CRYPTO, 0,
 253   dx_grmisc, dx_grdestroy,
 254   dx_grword, dx_grbyte, dx_grword, grand_range, dx_grfill
 255 };
 256
 257 /* ---@tlsdx_rand@ --- *
 258  *
 259  * Arguments:   @const gcmac *mc@ = MAC function to use
 260  *              @const void *k@ = pointer to the key material
 261  *              @size_t ksz@ = size of the key material
 262  *              @const void *sd@ = pointer to the seed material
 263  *              @size_t sdsz@ = size of the seed material
 264  *
 265  * Returns:     Pointer to generic random number generator interface.
 266  *
 267  * Use:         Creates a generic generator which does TLS data expansion.
 268  */
 269
 270 grand *tlsdx_rand(const gcmac *mc, const void *k, size_t ksz,
 271                   const void *sd, size_t sdsz)
 272 {
 273   dx_grctx *g = S_CREATE(dx_grctx);
 274   dstr d = DSTR_INIT;
 275   gmac *m = GM_KEY(mc, k, ksz);
 276   octet *q = xmalloc(sdsz);
 277   memcpy(q, sd, sdsz);
 278   dstr_putf(&d, "tlsdx(%s)", mc->name);
 279   g->ops = dx_grops;
 280   g->ops.name = xstrdup(d.buf);
 281   g->r.ops = &g->ops;
 282   dstr_destroy(&d);
 283   tlsdx_init(&g->dx, m, q, sdsz);
 284   return (&g->r);
 285 }
 286
 287 /* --- The actual very paranoid PRF ---------------------------------------*/
 288
 289 /* --- @tlsprf_init@ --- *
 290  *
 291  * Arguments:   @tlsprf_ctx *c@ = pointer to context block
 292  *              @const gcmac *mcx, *mcy@ = left and right MAC functions
 293  *              @const void *k@ = pointer to the key material
 294  *              @size_t ksz@ = size of the key material
 295  *              @const void *sd@ = pointer to the seed material
 296  *              @size_t sdsz@ = size of the seed material
 297  *
 298  * Returns:     ---
 299  *
 300  * Use:         Initializes a TLS PRF context.
 301  */
 302
 303 void tlsprf_init(tlsprf_ctx *c, const gcmac *mcx, const gcmac *mcy,
 304                  const void *k, size_t ksz, const void *sd, size_t sdsz)
 305 {
 306   size_t n = (ksz + 1)/2;
 307   const octet *kk = k;
 308   tlsdx_init(&c->px, mcx->key(kk, n), sd, sdsz);
 309   tlsdx_init(&c->py, mcy->key(kk + ksz - n, n), sd, sdsz);
 310 }
 311
 312 /* --- @tlsprf_encrypt@ --- *
 313  *
 314  * Arguments:   @tlsprf_ctx *c@ = pointer to a context
 315  *              @const void *src@ = pointer to source data
 316  *              @void *dest@ = pointer to destination buffer
 317  *              @size_t sz@ = size of buffer
 318  *
 319  * Returns:     ---
 320  *
 321  * Use:         Encrypts data using the TLS pseudo-random function.  If the
 322  *              destination pointer is null, the generator is spun and no
 323  *              output is produced; if the source pointer is null, raw output
 324  *              from the generator is written; otherwise, the source data is
 325  *              XORed with the generator output.
 326  */
 327
 328 void tlsprf_encrypt(tlsprf_ctx *c, const void *src, void *dest, size_t sz)
 329 {
 330   tlsdx_encrypt(&c->px, src, dest, sz);
 331   tlsdx_encrypt(&c->py, dest, dest, sz);
 332 }
 333
 334 /* --- @tlsprf_free@ --- *
 335  *
 336  * Arguments:   @tlsprf_ctx *c@ = pointer to a context
 337  *
 338  * Returns:     ---
 339  *
 340  * Use:         Frees a TLS PRF context.
 341  */
 342
 343 void tlsprf_free(tlsprf_ctx *c)
 344 {
 345   c->px.k->ops->destroy(c->px.k);
 346   c->py.k->ops->destroy(c->py.k);
 347   tlsdx_free(&c->px);
 348   tlsdx_free(&c->py);
 349 }
 350
 351 /* --- Generic random number generator --- */
 352
 353 typedef struct prf_grctx {
 354   grand r;
 355   grand_ops ops;
 356   tlsprf_ctx prf;
 357 } prf_grctx;
 358
 359 static void prf_grdestroy(grand *r)
 360 {
 361   prf_grctx *g = (prf_grctx *)r;
 362   xfree((char *)g->ops.name);
 363   xfree((octet *)g->prf.px.sd);
 364   tlsprf_free(&g->prf);
 365   BURN(*g);
 366   S_DESTROY(g);
 367 }
 368
 369 static void prf_seed(prf_grctx *g, const void *p, size_t sz)
 370 {
 371   octet *q;
 372
 373   xfree((octet *)g->prf.px.sz);
 374   g->prf.px.sd = g->prf.py.sd = q = xmalloc(sz);
 375   memcpy(q, p, sz);
 376   g->prf.px.sdsz = g->prf.py.sdsz = sz;
 377 }
 378
 379 static int prf_grmisc(grand *r, unsigned op, ...)
 380 {
 381   prf_grctx *g = (prf_grctx *)r;
 382   va_list ap;
 383   int rc = 0;
 384   uint32 i;
 385   octet buf[4];
 386   va_start(ap, op);
 387
 388   switch (op) {
 389     case GRAND_CHECK:
 390       switch (va_arg(ap, unsigned)) {
 391         case GRAND_CHECK:
 392         case GRAND_SEEDINT:
 393         case GRAND_SEEDUINT32:
 394         case GRAND_SEEDBLOCK:
 395         case GRAND_SEEDRAND:
 396           rc = 1;
 397           break;
 398         default:
 399           rc = 0;
 400           break;
 401       }
 402       break;
 403     case GRAND_SEEDINT:
 404       i = va_arg(ap, unsigned);
 405       STORE32(buf, i);
 406       prf_seed(g, buf, sizeof(buf));
 407       break;
 408     case GRAND_SEEDUINT32:
 409       i = va_arg(ap, uint32);
 410       STORE32(buf, i);
 411       prf_seed(g, buf, sizeof(buf));
 412       break;
 413     case GRAND_SEEDBLOCK: {
 414       const void *p = va_arg(ap, const void *);
 415       size_t sz = va_arg(ap, size_t);
 416       prf_seed(g, p, sz);
 417     } break;
 418     case GRAND_SEEDRAND: {
 419       grand *rr = va_arg(ap, grand *);
 420       octet buf[16];
 421       rr->ops->fill(rr, buf, sizeof(buf));
 422       prf_seed(g, buf, sizeof(buf));
 423     } break;
 424     default:
 425       GRAND_BADOP;
 426       break;
 427   }
 428
 429   va_end(ap);
 430   return (rc);
 431 }
 432
 433 static octet prf_grbyte(grand *r)
 434 {
 435   prf_grctx *g = (prf_grctx *)r;
 436   octet o;
 437   tlsprf_encrypt(&g->prf, 0, &o, 1);
 438   return (o);
 439 }
 440
 441 static uint32 prf_grword(grand *r)
 442 {
 443   prf_grctx *g = (prf_grctx *)r;
 444   octet b[4];
 445   tlsprf_encrypt(&g->prf, 0, &b, sizeof(b));
 446   return (LOAD32(b));
 447 }
 448
 449 static void prf_grfill(grand *r, void *p, size_t sz)
 450 {
 451   prf_grctx *g = (prf_grctx *)r;
 452   tlsprf_encrypt(&g->prf, 0, p, sz);
 453 }
 454
 455 static const grand_ops prf_grops = {
 456   "<tlsprf-dummy>",
 457   GRAND_CRYPTO, 0,
 458   prf_grmisc, prf_grdestroy,
 459   prf_grword, prf_grbyte, prf_grword, grand_range, prf_grfill
 460 };
 461
 462 /* ---@tlsprf_rand@ --- *
 463  *
 464  * Arguments:   @const gcmac *mcx, *mcy@ = MAC function to use
 465  *              @const void *k@ = pointer to the key material
 466  *              @size_t ksz@ = size of the key material
 467  *              @const void *sd@ = pointer to the seed material
 468  *              @size_t sdsz@ = size of the seed material
 469  *
 470  * Returns:     Pointer to generic random number generator interface.
 471  *
 472  * Use:         Creates a generic generator which does TLS data expansion.
 473  */
 474
 475 grand *tlsprf_rand(const gcmac *mcx, const gcmac *mcy,
 476                    const void *k, size_t ksz, const void *sd, size_t sdsz)
 477 {
 478   prf_grctx *g = S_CREATE(prf_grctx);
 479   dstr d = DSTR_INIT;
 480   octet *q = xmalloc(sdsz);
 481   memcpy(q, sd, sdsz);
 482   dstr_putf(&d, "tlsprf(%s,%s)", mcx->name, mcy->name);
 483   g->ops = prf_grops;
 484   g->ops.name = xstrdup(d.buf);
 485   g->r.ops = &g->ops;
 486   dstr_destroy(&d);
 487   tlsprf_init(&g->prf, mcx, mcy, k, ksz, q, sdsz);
 488   return (&g->r);
 489 }
 490
 491 /*----- Test rig ----------------------------------------------------------*/
 492
 493 #ifdef TEST_RIG
 494
 495 #include <stdio.h>
 496 #include <string.h>
 497
 498 #include <mLib/quis.h>
 499 #include <mLib/testrig.h>
 500
 501 #include "sha-hmac.h"
 502 #include "md5-hmac.h"
 503
 504 static int v_generate(dstr *v)
 505 {
 506   grand *g;
 507   dstr d = DSTR_INIT;
 508   int ok = 1;
 509
 510   g = tlsprf_rand(&md5_hmac, &sha_hmac,
 511                   v[0].buf, v[0].len, v[1].buf, v[1].len);
 512   dstr_ensure(&d, v[2].len);
 513   d.len = v[2].len;
 514   g->ops->fill(g, d.buf, d.len);
 515   g->ops->destroy(g);
 516   if (memcmp(v[2].buf, d.buf, d.len) != 0) {
 517     ok = 0;
 518     printf("\nfail tlsprf:"
 519            "\n\tkey        = ");
 520     type_hex.dump(&v[0], stdout);
 521     printf("\n\tseed       = "); type_hex.dump(&v[1], stdout);
 522     printf("\n\texpected   = "); type_hex.dump(&v[2], stdout);
 523     printf("\n\tcalculated = "); type_hex.dump(&d, stdout);
 524     putchar('\n');
 525   }
 526   return (ok);
 527 }
 528
 529 static test_chunk defs[] = {
 530   { "tlsprf", v_generate, { &type_hex, &type_hex, &type_hex, 0 } },
 531   { 0, 0, { 0 } }
 532 };
 533
 534 int main(int argc, char *argv[])
 535 {
 536   test_run(argc, argv, defs, SRCDIR"/tests/tlsprf");
 537   return (0);
 538 }
 539
 540 #endif
 541
 542 /*----- That's all, folks -------------------------------------------------*/