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

   1 /* -*-c-*-
   2  *
   3  * The SSL 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 "ghash.h"
  36 #include "grand.h"
  37 #include "paranoia.h"
  38 #include "sslprf.h"
  39
  40 /*----- Main code ---------------------------------------------------------*/
  41
  42 /* --- @step@ --- *
  43  *
  44  * Arguments:   @sslprf_ctx *c@ = pointer to context structure
  45  *
  46  * Returns:     ---
  47  *
  48  * Use:         Steps the generator.
  49  */
  50
  51 static void step(sslprf_ctx *c)
  52 {
  53   octet buf[64];
  54   size_t n, sz;
  55   octet x;
  56   ghash *h, *hh;
  57   octet *p;
  58
  59   h = GH_INIT(c->ci);
  60   x = 'A' + c->i - 1;
  61   for (sz = c->i++; sz > 0; sz -= n) {
  62     n = sz;
  63     if (n > sizeof(buf))
  64       n = sizeof(buf);
  65     memset(buf, x, n);
  66     GH_HASH(h, buf, n);
  67   }
  68   GH_HASH(h, c->k, c->ksz);
  69   GH_HASH(h, c->sd, c->sdsz);
  70   p = GH_DONE(h, 0);
  71
  72   hh = GH_INIT(c->co);
  73   GH_HASH(hh, c->k, c->ksz);
  74   GH_HASH(hh, p, c->ihashsz);
  75   c->p = GH_DONE(hh, 0);
  76   GH_DESTROY(h);
  77
  78   c->h = hh;
  79   c->sz = c->ohashsz;
  80 }
  81
  82 /* --- @sslprf_init@ --- *
  83  *
  84  * Arguments:   @sslprf_ctx *c@ = pointer to a context structure
  85  *              @const gchash *hco, *hci@ = outer and inner hash functions
  86  *              @const void *k@ = pointer to secret buffer
  87  *              @size_t ksz@ = size of the secret
  88  *              @const void *sd@ = pointer to seed buffer
  89  *              @size_t sdsz@ = size of the seed
  90  *
  91  * Returns:     ---
  92  *
  93  * Use:         Initializes an SSL generator context.
  94  */
  95
  96 void sslprf_init(sslprf_ctx *c, const gchash *hco, const gchash *hci,
  97                  const void *k, size_t ksz,
  98                  const void *sd, size_t sdsz)
  99 {
 100   c->co = hco; c->ci = hci;
 101   c->ohashsz = hco->hashsz; c->ihashsz = hci->hashsz;
 102   c->k = k; c->ksz = ksz; c->sd = sd; c->sdsz = sdsz;
 103   c->i = 1;
 104   step(c);
 105 }
 106
 107 /* --- @sslprf_encrypt@ --- *
 108  *
 109  * Arguments:   @sslprf_ctx *c@ = pointer to a context structure
 110  *              @const void *src@ = pointer to source buffer
 111  *              @void *dest@ = pointer to destination buffer
 112  *              @size_t sz@ = size of the buffers
 113  *
 114  * Returns:     ---
 115  *
 116  * Use:         Encrypts data using the SSL pseudo-random function.  If the
 117  *              destination pointer is null, the generator is spun and no
 118  *              output is produced; if the source pointer is null, raw output
 119  *              from the generator is written; otherwise, the source data is
 120  *              XORed with the generator output.
 121  */
 122
 123 void sslprf_encrypt(sslprf_ctx *c, const void *src, void *dest, size_t sz)
 124 {
 125   const octet *s = src;
 126   octet *d = dest;
 127   size_t i, n;
 128
 129   while (sz) {
 130     if (!c->sz) {
 131       GH_DESTROY(c->h);
 132       step(c);
 133     }
 134     n = c->sz;
 135     if (n > sz)
 136       n = sz;
 137     if (d) {
 138       if (!s)
 139         memcpy(d, c->p, n);
 140       else {
 141         for (i = 0; i < n; i++) d[i] = s[i] ^ c->p[i];
 142         s += n;
 143       }
 144       d += n;
 145     }
 146     c->p += n;
 147     c->sz -= n;
 148     sz -= n;
 149   }
 150 }
 151
 152 /* --- @sslprf_free@ --- *
 153  *
 154  * Arguments:   @sslprf_ctx@ = pointer to a context
 155  *
 156  * Returns:     ---
 157  *
 158  * Use:         Frees resources held in an SSL generator context.
 159  */
 160
 161 void sslprf_free(sslprf_ctx *c)
 162 {
 163   GH_DESTROY(c->h);
 164 }
 165
 166 /* --- Generic random number generator --- */
 167
 168 typedef struct grctx {
 169   grand r;
 170   grand_ops ops;
 171   sslprf_ctx prf;
 172 } grctx;
 173
 174 static void grdestroy(grand *r)
 175 {
 176   grctx *g = (grctx *)r;
 177   xfree((char *)g->ops.name);
 178   xfree((octet *)g->prf.sd);
 179   sslprf_free(&g->prf);
 180   BURN(*g);
 181   S_DESTROY(g);
 182 }
 183
 184 static void seed(grctx *g, const void *p, size_t sz)
 185 {
 186   octet *q;
 187   xfree((octet *)g->prf.sd);
 188   g->prf.sd = q = xmalloc(sz);
 189   memcpy(q, p, sz);
 190   g->prf.sdsz = sz;
 191 }
 192
 193 static int grmisc(grand *r, unsigned op, ...)
 194 {
 195   grctx *g = (grctx *)r;
 196   va_list ap;
 197   int rc = 0;
 198   uint32 i;
 199   octet buf[4];
 200   va_start(ap, op);
 201
 202   switch (op) {
 203     case GRAND_CHECK:
 204       switch (va_arg(ap, unsigned)) {
 205         case GRAND_CHECK:
 206         case GRAND_SEEDINT:
 207         case GRAND_SEEDUINT32:
 208         case GRAND_SEEDBLOCK:
 209         case GRAND_SEEDRAND:
 210           rc = 1;
 211           break;
 212         default:
 213           rc = 0;
 214           break;
 215       }
 216       break;
 217     case GRAND_SEEDINT:
 218       i = va_arg(ap, unsigned);
 219       STORE32(buf, i);
 220       seed(g, buf, sizeof(buf));
 221       break;
 222     case GRAND_SEEDUINT32:
 223       i = va_arg(ap, uint32);
 224       STORE32(buf, i);
 225       seed(g, buf, sizeof(buf));
 226       break;
 227     case GRAND_SEEDBLOCK: {
 228       const void *p = va_arg(ap, const void *);
 229       size_t sz = va_arg(ap, size_t);
 230       seed(g, p, sz);
 231     } break;
 232     case GRAND_SEEDRAND: {
 233       grand *rr = va_arg(ap, grand *);
 234       octet buf[16];
 235       rr->ops->fill(rr, buf, sizeof(buf));
 236       seed(g, buf, sizeof(buf));
 237     } break;
 238     default:
 239       GRAND_BADOP;
 240       break;
 241   }
 242
 243   va_end(ap);
 244   return (rc);
 245 }
 246
 247 static octet grbyte(grand *r)
 248 {
 249   grctx *g = (grctx *)r;
 250   octet o;
 251   sslprf_encrypt(&g->prf, 0, &o, 1);
 252   return (o);
 253 }
 254
 255 static uint32 grword(grand *r)
 256 {
 257   grctx *g = (grctx *)r;
 258   octet b[4];
 259   sslprf_encrypt(&g->prf, 0, &b, sizeof(b));
 260   return (LOAD32(b));
 261 }
 262
 263 static void grfill(grand *r, void *p, size_t sz)
 264 {
 265   grctx *g = (grctx *)r;
 266   sslprf_encrypt(&g->prf, 0, p, sz);
 267 }
 268
 269 static const grand_ops grops = {
 270   "<sslprf-dummy>",
 271   GRAND_CRYPTO, 0,
 272   grmisc, grdestroy,
 273   grword, grbyte, grword, grand_range, grfill
 274 };
 275
 276 /* ---@sslprf_rand@ --- *
 277  *
 278  * Arguments:   @const gchash *hco, const gchash *hci@ = hash functions
 279  *              @const void *k@ = pointer to the key material
 280  *              @size_t ksz@ = size of the key material
 281  *              @const void *sd@ = pointer to the seed material
 282  *              @size_t sdsz@ = size of the seed material
 283  *
 284  * Returns:     Pointer to generic random number generator interface.
 285  *
 286  * Use:         Creates a generic generator which does TLS data expansion.
 287  */
 288
 289 grand *sslprf_rand(const gchash *hco, const gchash *hci,
 290                    const void *k, size_t ksz,
 291                    const void *sd, size_t sdsz)
 292 {
 293   grctx *g = S_CREATE(grctx);
 294   dstr d = DSTR_INIT;
 295   octet *q = xmalloc(sdsz);
 296   memcpy(q, sd, sdsz);
 297   dstr_putf(&d, "sslprf(%s,%s)", hco->name, hci->name);
 298   g->ops = grops;
 299   g->ops.name = xstrdup(d.buf);
 300   g->r.ops = &g->ops;
 301   dstr_destroy(&d);
 302   sslprf_init(&g->prf, hco, hci, k, ksz, q, sdsz);
 303   return (&g->r);
 304 }
 305
 306 /*----- Test rig ----------------------------------------------------------*/
 307
 308 #ifdef TEST_RIG
 309
 310 #include <stdio.h>
 311 #include <string.h>
 312
 313 #include <mLib/quis.h>
 314 #include <mLib/testrig.h>
 315
 316 #include "sha.h"
 317 #include "md5.h"
 318
 319 static int v_generate(dstr *v)
 320 {
 321   grand *g;
 322   dstr d = DSTR_INIT;
 323   int ok = 1;
 324
 325   g = sslprf_rand(&md5, &sha, v[0].buf, v[0].len, v[1].buf, v[1].len);
 326   dstr_ensure(&d, v[2].len);
 327   d.len = v[2].len;
 328   g->ops->fill(g, d.buf, d.len);
 329   g->ops->destroy(g);
 330   if (memcmp(v[2].buf, d.buf, d.len) != 0) {
 331     ok = 0;
 332     printf("\nfail sslprf:"
 333            "\n\tkey        = ");
 334     type_hex.dump(&v[0], stdout);
 335     printf("\n\tseed       = "); type_hex.dump(&v[1], stdout);
 336     printf("\n\texpected   = "); type_hex.dump(&v[2], stdout);
 337     printf("\n\tcalculated = "); type_hex.dump(&d, stdout);
 338     putchar('\n');
 339   }
 340   return (ok);
 341 }
 342
 343 static test_chunk defs[] = {
 344   { "sslprf", v_generate, { &type_hex, &type_hex, &type_hex, 0 } },
 345   { 0, 0, { 0 } }
 346 };
 347
 348 int main(int argc, char *argv[])
 349 {
 350   test_run(argc, argv, defs, SRCDIR"/t/sslprf");
 351   return (0);
 352 }
 353
 354 #endif
 355
 356 /*----- That's all, folks -------------------------------------------------*/