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

   1 /* -*-c-*-
   2  *
   3  * $Id: sslprf.c,v 1.2 2004/04/08 01:36:15 mdw Exp $
   4  *
   5  * The SSL 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 "ghash.h"
  38 #include "grand.h"
  39 #include "paranoia.h"
  40 #include "sslprf.h"
  41
  42 /*----- Main code ---------------------------------------------------------*/
  43
  44 /* --- @step@ --- *
  45  *
  46  * Arguments:   @sslprf_ctx *c@ = pointer to context structure
  47  *
  48  * Returns:     ---
  49  *
  50  * Use:         Steps the generator.
  51  */
  52
  53 static void step(sslprf_ctx *c)
  54 {
  55   octet buf[64];
  56   size_t n, sz;
  57   octet x;
  58   ghash *h, *hh;
  59   octet *p;
  60
  61   h = GH_INIT(c->ci);
  62   x = 'A' + c->i - 1;
  63   for (sz = c->i++; sz > 0; sz -= n) {
  64     n = sz;
  65     if (n > sizeof(buf))
  66       n = sizeof(buf);
  67     memset(buf, x, n);
  68     GH_HASH(h, buf, n);
  69   }
  70   GH_HASH(h, c->k, c->ksz);
  71   GH_HASH(h, c->sd, c->sdsz);
  72   p = GH_DONE(h, 0);
  73
  74   hh = GH_INIT(c->co);
  75   GH_HASH(hh, c->k, c->ksz);
  76   GH_HASH(hh, p, c->ihashsz);
  77   c->p = GH_DONE(hh, 0);
  78   GH_DESTROY(h);
  79
  80   c->h = hh;
  81   c->sz = c->ohashsz;
  82 }
  83
  84 /* --- @sslprf_init@ --- *
  85  *
  86  * Arguments:   @sslprf_ctx *c@ = pointer to a context structure
  87  *              @const gchash *hco, *hci@ = outer and inner hash functions
  88  *              @const void *k@ = pointer to secret buffer
  89  *              @size_t ksz@ = size of the secret
  90  *              @const void *sd@ = pointer to seed buffer
  91  *              @size_t sdsz@ = size of the seed
  92  *
  93  * Returns:     ---
  94  *
  95  * Use:         Initializes an SSL generator context.
  96  */
  97
  98 void sslprf_init(sslprf_ctx *c, const gchash *hco, const gchash *hci,
  99                  const void *k, size_t ksz,
 100                  const void *sd, size_t sdsz)
 101 {
 102   c->co = hco; c->ci = hci;
 103   c->ohashsz = hco->hashsz; c->ihashsz = hci->hashsz;
 104   c->k = k; c->ksz = ksz; c->sd = sd; c->sdsz = sdsz;
 105   c->i = 1;
 106   step(c);
 107 }
 108
 109 /* --- @sslprf_encrypt@ --- *
 110  *
 111  * Arguments:   @sslprf_ctx *c@ = pointer to a context structure
 112  *              @const void *src@ = pointer to source buffer
 113  *              @void *dest@ = pointer to destination buffer
 114  *              @size_t sz@ = size of the buffers
 115  *
 116  * Returns:     ---
 117  *
 118  * Use:         Encrypts data using the SSL pseudo-random function.  If the
 119  *              destination pointer is null, the generator is spun and no
 120  *              output is produced; if the source pointer is null, raw output
 121  *              from the generator is written; otherwise, the source data is
 122  *              XORed with the generator output.
 123  */
 124
 125 void sslprf_encrypt(sslprf_ctx *c, const void *src, void *dest, size_t sz)
 126 {
 127   const octet *s = src;
 128   octet *d = dest;
 129   size_t i, n;
 130
 131   while (sz) {
 132     if (!c->sz) {
 133       GH_DESTROY(c->h);
 134       step(c);
 135     }
 136     n = c->sz;
 137     if (n > sz)
 138       n = sz;
 139     if (d) {
 140       if (!s)
 141         memcpy(d, c->p, n);
 142       else {
 143         for (i = 0; i < n; i++) d[i] = s[i] ^ c->p[i];
 144         s += n;
 145       }
 146       d += n;
 147     }
 148     c->p += n;
 149     c->sz -= n;
 150     sz -= n;
 151   }
 152 }
 153
 154 /* --- @sslprf_free@ --- *
 155  *
 156  * Arguments:   @sslprf_ctx@ = pointer to a context
 157  *
 158  * Returns:     ---
 159  *
 160  * Use:         Frees resources held in an SSL generator context.
 161  */
 162
 163 void sslprf_free(sslprf_ctx *c)
 164 {
 165   GH_DESTROY(c->h);
 166 }
 167
 168 /* --- Generic random number generator --- */
 169
 170 typedef struct grctx {
 171   grand r;
 172   grand_ops ops;
 173   sslprf_ctx prf;
 174 } grctx;
 175
 176 static void grdestroy(grand *r)
 177 {
 178   grctx *g = (grctx *)r;
 179   xfree((char *)g->ops.name);
 180   xfree((octet *)g->prf.sd);
 181   sslprf_free(&g->prf);
 182   BURN(*g);
 183   S_DESTROY(g);
 184 }
 185
 186 static void seed(grctx *g, const void *p, size_t sz)
 187 {
 188   octet *q;
 189   xfree((octet *)g->prf.sd);
 190   g->prf.sd = q = xmalloc(sz);
 191   memcpy(q, p, sz);
 192   g->prf.sdsz = sz;
 193 }
 194
 195 static int grmisc(grand *r, unsigned op, ...)
 196 {
 197   grctx *g = (grctx *)r;
 198   va_list ap;
 199   int rc = 0;
 200   uint32 i;
 201   octet buf[4];
 202   va_start(ap, op);
 203
 204   switch (op) {
 205     case GRAND_CHECK:
 206       switch (va_arg(ap, unsigned)) {
 207         case GRAND_CHECK:
 208         case GRAND_SEEDINT:
 209         case GRAND_SEEDUINT32:
 210         case GRAND_SEEDBLOCK:
 211         case GRAND_SEEDRAND:
 212           rc = 1;
 213           break;
 214         default:
 215           rc = 0;
 216           break;
 217       }
 218       break;
 219     case GRAND_SEEDINT:
 220       i = va_arg(ap, unsigned);
 221       STORE32(buf, i);
 222       seed(g, buf, sizeof(buf));
 223       break;
 224     case GRAND_SEEDUINT32:
 225       i = va_arg(ap, uint32);
 226       STORE32(buf, i);
 227       seed(g, buf, sizeof(buf));
 228       break;
 229     case GRAND_SEEDBLOCK: {
 230       const void *p = va_arg(ap, const void *);
 231       size_t sz = va_arg(ap, size_t);
 232       seed(g, p, sz);
 233     } break;
 234     case GRAND_SEEDRAND: {
 235       grand *rr = va_arg(ap, grand *);
 236       octet buf[16];
 237       rr->ops->fill(rr, buf, sizeof(buf));
 238       seed(g, buf, sizeof(buf));
 239     } break;
 240     default:
 241       GRAND_BADOP;
 242       break;
 243   }
 244
 245   va_end(ap);
 246   return (rc);
 247 }
 248
 249 static octet grbyte(grand *r)
 250 {
 251   grctx *g = (grctx *)r;
 252   octet o;
 253   sslprf_encrypt(&g->prf, 0, &o, 1);
 254   return (o);
 255 }
 256
 257 static uint32 grword(grand *r)
 258 {
 259   grctx *g = (grctx *)r;
 260   octet b[4];
 261   sslprf_encrypt(&g->prf, 0, &b, sizeof(b));
 262   return (LOAD32(b));
 263 }
 264
 265 static void grfill(grand *r, void *p, size_t sz)
 266 {
 267   grctx *g = (grctx *)r;
 268   sslprf_encrypt(&g->prf, 0, p, sz);
 269 }
 270
 271 static const grand_ops grops = {
 272   "<sslprf-dummy>",
 273   GRAND_CRYPTO, 0,
 274   grmisc, grdestroy,
 275   grword, grbyte, grword, grand_range, grfill
 276 };
 277
 278 /* ---@sslprf_rand@ --- *
 279  *
 280  * Arguments:   @const gchash *hco, const gchash *hci@ = hash functions
 281  *              @const void *k@ = pointer to the key material
 282  *              @size_t ksz@ = size of the key material
 283  *              @const void *sd@ = pointer to the seed material
 284  *              @size_t sdsz@ = size of the seed material
 285  *
 286  * Returns:     Pointer to generic random number generator interface.
 287  *
 288  * Use:         Creates a generic generator which does TLS data expansion.
 289  */
 290
 291 grand *sslprf_rand(const gchash *hco, const gchash *hci,
 292                    const void *k, size_t ksz,
 293                    const void *sd, size_t sdsz)
 294 {
 295   grctx *g = S_CREATE(grctx);
 296   dstr d = DSTR_INIT;
 297   octet *q = xmalloc(sdsz);
 298   memcpy(q, sd, sdsz);
 299   dstr_putf(&d, "sslprf(%s,%s)", hco->name, hci->name);
 300   g->ops = grops;
 301   g->ops.name = xstrdup(d.buf);
 302   g->r.ops = &g->ops;
 303   dstr_destroy(&d);
 304   sslprf_init(&g->prf, hco, hci, k, ksz, q, sdsz);
 305   return (&g->r);
 306 }
 307
 308 /*----- Test rig ----------------------------------------------------------*/
 309
 310 #ifdef TEST_RIG
 311
 312 #include <stdio.h>
 313 #include <string.h>
 314
 315 #include <mLib/quis.h>
 316 #include <mLib/testrig.h>
 317
 318 #include "sha.h"
 319 #include "md5.h"
 320
 321 static int v_generate(dstr *v)
 322 {
 323   grand *g;
 324   dstr d = DSTR_INIT;
 325   int ok = 1;
 326
 327   g = sslprf_rand(&md5, &sha, v[0].buf, v[0].len, v[1].buf, v[1].len);
 328   dstr_ensure(&d, v[2].len);
 329   d.len = v[2].len;
 330   g->ops->fill(g, d.buf, d.len);
 331   g->ops->destroy(g);
 332   if (memcmp(v[2].buf, d.buf, d.len) != 0) {
 333     ok = 0;
 334     printf("\nfail sslprf:"
 335            "\n\tkey        = ");
 336     type_hex.dump(&v[0], stdout);
 337     printf("\n\tseed       = "); type_hex.dump(&v[1], stdout);
 338     printf("\n\texpected   = "); type_hex.dump(&v[2], stdout);
 339     printf("\n\tcalculated = "); type_hex.dump(&d, stdout);
 340     putchar('\n');
 341   }
 342   return (ok);
 343 }
 344
 345 static test_chunk defs[] = {
 346   { "sslprf", v_generate, { &type_hex, &type_hex, &type_hex, 0 } },
 347   { 0, 0, { 0 } }
 348 };
 349
 350 int main(int argc, char *argv[])
 351 {
 352   test_run(argc, argv, defs, SRCDIR"/tests/sslprf");
 353   return (0);
 354 }
 355
 356 #endif
 357
 358 /*----- That's all, folks -------------------------------------------------*/