chiark - git - mdw - catacomb/blob - hash.h

   1 /* -*-c-*-
   2  *
   3  * $Id$
   4  *
   5  * Generic handling for message digest functions
   6  *
   7  * (c) 1998 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 #ifndef CATACOMB_HASH_H
  31 #define CATACOMB_HASH_H
  32
  33 #ifdef __cplusplus
  34   extern "C" {
  35 #endif
  36
  37 /*----- Header files ------------------------------------------------------*/
  38
  39 #include <string.h>
  40
  41 #include <mLib/bits.h>
  42
  43 /*----- Macros ------------------------------------------------------------*/
  44
  45 /* --- @HASH_BUFFER@ --- *
  46  *
  47  * Arguments:   @PRE@, @pre@ = prefixes for hash-specific definitions
  48  *              @ictx@ = pointer to context block for the hash
  49  *              @ibuf@ = pointer to input data to hash
  50  *              @isz@ = size of buffer
  51  *
  52  * Use:         Handles buffering of input data to a hash function.  The
  53  *              hash's compression function is called when the buffer is
  54  *              full.  Note that the compression function can be called on
  55  *              data which is at odd alignments; it is expected to cope
  56  *              gracefully with this (possibly by copying the data into its
  57  *              internal buffer before starting).
  58  */
  59
  60 #define HASH_BUFFER(PRE, pre, ictx, ibuf, isz) do {                     \
  61   pre##_ctx *_bctx = (ictx);                                            \
  62   size_t _bsz = (isz);                                                  \
  63   const octet *_bbuf = (octet *)(ibuf);                                 \
  64                                                                         \
  65   /* --- Add on the size done so far --- *                              \
  66    *                                                                    \
  67    * Messy, because trapping overflow is difficult when you don't know  \
  68    * how many bits you've actually got.                                 \
  69    */                                                                   \
  70                                                                         \
  71   {                                                                     \
  72     uint32 _l = U32(_bsz);                                              \
  73     uint32 _h = ((_bsz & ~MASK32) >> 16) >> 16;                         \
  74     _bctx->nh += _h;                                                    \
  75     _bctx->nl += _l;                                                    \
  76     if (_bctx->nl < _l || _bctx->nl & ~MASK32)                          \
  77       _bctx->nh++;                                                      \
  78   }                                                                     \
  79                                                                         \
  80   /* --- Handle very small contributions --- */                         \
  81                                                                         \
  82   if (_bctx->off + _bsz < PRE##_BUFSZ) {                                \
  83     memcpy(_bctx->buf + _bctx->off, _bbuf, _bsz);                       \
  84     _bctx->off += _bsz;                                                 \
  85   } else {                                                              \
  86                                                                         \
  87     /* --- Handle an initial partial buffer --- */                      \
  88                                                                         \
  89     if (_bctx->off) {                                                   \
  90       size_t s = PRE##_BUFSZ - _bctx->off;                              \
  91       memcpy(_bctx->buf + _bctx->off, _bbuf, s);                        \
  92       pre##_compress(_bctx, _bctx->buf);                                \
  93       _bsz -= s; _bbuf += s;                                            \
  94     }                                                                   \
  95                                                                         \
  96     /* --- Do whole buffers while we can --- */                         \
  97                                                                         \
  98     while (_bsz >= PRE##_BUFSZ) {                                       \
  99       pre##_compress(_bctx, _bbuf);                                     \
 100       _bsz -= PRE##_BUFSZ; _bbuf += PRE##_BUFSZ;                        \
 101     }                                                                   \
 102                                                                         \
 103     /* --- And wrap up at the end --- */                                \
 104                                                                         \
 105     if (_bsz)                                                           \
 106       memcpy(_bctx->buf, _bbuf, _bsz);                                  \
 107     _bctx->off = _bsz;                                                  \
 108   }                                                                     \
 109 } while (0)
 110
 111 /* --- @HASH_PAD@ --- *
 112  *
 113  * Arguments:   @PRE@, @pre@ = prefixes for hash-specific definitions
 114  *              @ictx@ = pointer to context block for the hash
 115  *              @term@ = terminator character to write following the data
 116  *              @pad@ = pad character to fill with
 117  *              @diff@ = size of space to leave at the end of the last block
 118  *
 119  * Use:         Does padding for message digest functions.
 120  */
 121
 122 #define HASH_PAD(PRE, pre, ictx, term, pad, diff) do {                  \
 123   pre##_ctx *_pctx = (ictx);                                            \
 124                                                                         \
 125   _pctx->buf[_pctx->off] = term;                                        \
 126   _pctx->off++;                                                         \
 127   if (_pctx->off > PRE##_BUFSZ - diff) {                                \
 128     if (_pctx->off < PRE##_BUFSZ)                                       \
 129       memset(_pctx->buf + _pctx->off, pad, PRE##_BUFSZ - _pctx->off);   \
 130     pre##_compress(_pctx, _pctx->buf);                                  \
 131     memset(_pctx->buf, pad, PRE##_BUFSZ - diff);                        \
 132   } else                                                                \
 133     memset(_pctx->buf + _pctx->off, pad,                                \
 134            PRE##_BUFSZ - _pctx->off - diff);                            \
 135 } while (0)
 136
 137 /* --- @HASH_MD5STRENGTH@ --- *
 138  *
 139  * Arguments:   @PRE@, @pre@ = prefixes for hash-specific definitions
 140  *              @ictx@ = pointer to context block for the hash
 141  *
 142  * Use:         Does MD5-style MD strengthening.  The data is terminated
 143  *              by a single set bit, padded with zero bits, and then a 64-
 144  *              bit length is written, little-end first.
 145  */
 146
 147 #define HASH_MD5STRENGTH(PRE, pre, ictx) do {                           \
 148   pre##_ctx *_mctx = (ictx);                                            \
 149   HASH_PAD(PRE, pre, _mctx, 0x80u, 0, 8);                               \
 150   STORE32_L(_mctx->buf + PRE##_BUFSZ - 8, _mctx->nl << 3);              \
 151   STORE32_L(_mctx->buf + PRE##_BUFSZ - 4,                               \
 152             (_mctx->nl >> 29) | (_mctx->nh << 3));                      \
 153   pre##_compress(_mctx, _mctx->buf);                                    \
 154 } while (0)
 155
 156 /* --- @HASH_TEST@ --- *
 157  *
 158  * Arguments:   @PRE@, @pre@ = prefixes for hash-specfic definitions
 159  *
 160  * Use:         Standard test rig for hash functions.
 161  */
 162
 163 #ifdef TEST_RIG
 164
 165 #include <mLib/quis.h>
 166 #include <mLib/testrig.h>
 167
 168 #define HASH_BUFLEN 100000
 169
 170 #define HASH_TEST(PRE, pre)                                             \
 171                                                                         \
 172 static int verify(dstr *v)                                              \
 173 {                                                                       \
 174   pre##_ctx ctx;                                                        \
 175   int ok = 1;                                                           \
 176   int i;                                                                \
 177   octet *p;                                                             \
 178   int szs[] = { 1, 7, 192, -1, 0 }, *ip;                                \
 179   size_t sz;                                                            \
 180   dstr d;                                                               \
 181                                                                         \
 182   dstr_create(&d);                                                      \
 183   dstr_ensure(&d, PRE##_HASHSZ);                                        \
 184   d.len = PRE##_HASHSZ;                                                 \
 185                                                                         \
 186   for (ip = szs; *ip; ip++) {                                           \
 187     i = *ip;                                                            \
 188     sz = v[0].len;                                                      \
 189     if (i == -1)                                                        \
 190       i = sz;                                                           \
 191     if (i > sz)                                                         \
 192       continue;                                                         \
 193     p = (octet *)v[0].buf;                                              \
 194     pre##_init(&ctx);                                                   \
 195     while (sz) {                                                        \
 196       if (i > sz)                                                       \
 197         i = sz;                                                         \
 198       pre##_hash(&ctx, p, i);                                           \
 199       p += i;                                                           \
 200       sz -= i;                                                          \
 201     }                                                                   \
 202     pre##_done(&ctx, d.buf);                                            \
 203     if (memcmp(d.buf, v[1].buf, PRE##_HASHSZ) != 0) {                   \
 204       printf("\nfail:\n\tstep = %i\n\tinput = `%s'\n\texpected = ",     \
 205              *ip, v[0].buf);                                            \
 206       type_hex.dump(&v[1], stdout);                                     \
 207       fputs("\n\tcomputed = ", stdout);                                 \
 208       type_hex.dump(&d, stdout);                                        \
 209       putchar('\n');                                                    \
 210       ok = 0;                                                           \
 211     }                                                                   \
 212   }                                                                     \
 213                                                                         \
 214   dstr_destroy(&d);                                                     \
 215   return (ok);                                                          \
 216 }                                                                       \
 217                                                                         \
 218 static int verifyrep(dstr *v)                                           \
 219 {                                                                       \
 220   pre##_ctx ctx;                                                        \
 221   size_t len = v[0].len;                                                \
 222   int n = *(int *)v[1].buf;                                             \
 223   int nd = 0;                                                           \
 224   int nn = len;                                                         \
 225   int ok = 1;                                                           \
 226   octet *p, *q;                                                         \
 227   dstr d = DSTR_INIT;                                                   \
 228                                                                         \
 229   while (nn < HASH_BUFLEN && (n & 1) == 0) { nd++; nn <<= 1; n >>= 1; } \
 230   p = xmalloc(nn);                                                      \
 231   memcpy(p, v[0].buf, len);                                             \
 232   q = p + len;                                                          \
 233   while (nd--) { memcpy(q, p, len); q += len; len <<= 1; }              \
 234                                                                         \
 235   dstr_ensure(&d, PRE##_HASHSZ);                                        \
 236   d.len = PRE##_HASHSZ;                                                 \
 237   pre##_init(&ctx);                                                     \
 238   while (n--) pre##_hash(&ctx, p, len);                                 \
 239   pre##_done(&ctx, d.buf);                                              \
 240                                                                         \
 241   if (memcmp(d.buf, v[2].buf, PRE##_HASHSZ) != 0) {                     \
 242     printf("\nfail:\n\tinput = `%s'\n\treps = `%i'\n\texpected = ",     \
 243              v[0].buf, *(int *)v[1].buf);                               \
 244     type_hex.dump(&v[2], stdout);                                       \
 245     fputs("\n\tcomputed = ", stdout);                                   \
 246     type_hex.dump(&d, stdout);                                          \
 247     putchar('\n');                                                      \
 248     ok = 0;                                                             \
 249   }                                                                     \
 250   xfree(p);                                                             \
 251   dstr_destroy(&d);                                                     \
 252   return (ok);                                                          \
 253 }                                                                       \
 254                                                                         \
 255 static test_chunk defs[] = {                                            \
 256   { #pre, verify, { &type_string, &type_hex, 0 } },                     \
 257   { #pre "-rep", verifyrep,                                             \
 258     { &type_string, &type_int, &type_hex, 0 } },                        \
 259   { 0, 0, { 0 } }                                                       \
 260 };                                                                      \
 261                                                                         \
 262 int main(int argc, char *argv[])                                        \
 263 {                                                                       \
 264   ego(argv[0]);                                                         \
 265   test_run(argc, argv, defs, SRCDIR"/tests/" #pre);                     \
 266   return (0);                                                           \
 267 }
 268
 269 #else
 270 #  define HASH_TEST(PRE, pre)
 271 #endif
 272
 273 /*----- That's all, folks -------------------------------------------------*/
 274
 275 #ifdef __cplusplus
 276   }
 277 #endif
 278
 279 #endif