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

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