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

   1 /* -*-c-*-
   2  *
   3  * Generic handling for message digest functions
   4  *
   5  * (c) 1998 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 #ifndef CATACOMB_HASH_H
  29 #define CATACOMB_HASH_H
  30
  31 #ifdef __cplusplus
  32   extern "C" {
  33 #endif
  34
  35 /*----- Header files ------------------------------------------------------*/
  36
  37 #include <string.h>
  38
  39 #include <mLib/bits.h>
  40
  41 /*----- Macros ------------------------------------------------------------*/
  42
  43 /* --- @HASH_BUFFER@ --- *
  44  *
  45  * Arguments:   @PRE@, @pre@ = prefixes for hash-specific definitions
  46  *              @ictx@ = pointer to context block for the hash
  47  *              @ibuf@ = pointer to input data to hash
  48  *              @isz@ = size of buffer
  49  *
  50  * Use:         Handles buffering of input data to a hash function.  The
  51  *              hash's compression function is called when the buffer is
  52  *              full.  Note that the compression function can be called on
  53  *              data which is at odd alignments; it is expected to cope
  54  *              gracefully with this (possibly by copying the data into its
  55  *              internal buffer before starting).
  56  */
  57
  58 #define HASH_BUFFER(PRE, pre, ictx, ibuf, isz) do {                     \
  59   pre##_ctx *_bctx = (ictx);                                            \
  60   size_t _bsz = (isz);                                                  \
  61   const octet *_bbuf = (octet *)(ibuf);                                 \
  62                                                                         \
  63   /* --- Add on the size done so far --- *                              \
  64    *                                                                    \
  65    * Messy, because trapping overflow is difficult when you don't know  \
  66    * how many bits you've actually got.                                 \
  67    */                                                                   \
  68                                                                         \
  69   {                                                                     \
  70     uint32 _l = U32(_bsz);                                              \
  71     uint32 _h = ((_bsz & ~MASK32) >> 16) >> 16;                         \
  72     _bctx->nh += _h;                                                    \
  73     _bctx->nl += _l;                                                    \
  74     if (_bctx->nl < _l || _bctx->nl & ~MASK32)                          \
  75       _bctx->nh++;                                                      \
  76   }                                                                     \
  77                                                                         \
  78   /* --- Handle very small contributions --- */                         \
  79                                                                         \
  80   if (_bctx->off + _bsz < PRE##_BUFSZ) {                                \
  81     memcpy(_bctx->buf + _bctx->off, _bbuf, _bsz);                       \
  82     _bctx->off += _bsz;                                                 \
  83   } else {                                                              \
  84                                                                         \
  85     /* --- Handle an initial partial buffer --- */                      \
  86                                                                         \
  87     if (_bctx->off) {                                                   \
  88       size_t s = PRE##_BUFSZ - _bctx->off;                              \
  89       memcpy(_bctx->buf + _bctx->off, _bbuf, s);                        \
  90       pre##_compress(_bctx, _bctx->buf);                                \
  91       _bsz -= s; _bbuf += s;                                            \
  92     }                                                                   \
  93                                                                         \
  94     /* --- Do whole buffers while we can --- */                         \
  95                                                                         \
  96     while (_bsz >= PRE##_BUFSZ) {                                       \
  97       pre##_compress(_bctx, _bbuf);                                     \
  98       _bsz -= PRE##_BUFSZ; _bbuf += PRE##_BUFSZ;                        \
  99     }                                                                   \
 100                                                                         \
 101     /* --- And wrap up at the end --- */                                \
 102                                                                         \
 103     if (_bsz)                                                           \
 104       memcpy(_bctx->buf, _bbuf, _bsz);                                  \
 105     _bctx->off = _bsz;                                                  \
 106   }                                                                     \
 107 } while (0)
 108
 109 /* --- @HASH_PAD@ --- *
 110  *
 111  * Arguments:   @PRE@, @pre@ = prefixes for hash-specific definitions
 112  *              @ictx@ = pointer to context block for the hash
 113  *              @term@ = terminator character to write following the data
 114  *              @pad@ = pad character to fill with
 115  *              @diff@ = size of space to leave at the end of the last block
 116  *
 117  * Use:         Does padding for message digest functions.
 118  */
 119
 120 #define HASH_PAD(PRE, pre, ictx, term, pad, diff) do {                  \
 121   pre##_ctx *_pctx = (ictx);                                            \
 122                                                                         \
 123   _pctx->buf[_pctx->off] = term;                                        \
 124   _pctx->off++;                                                         \
 125   if (_pctx->off > PRE##_BUFSZ - diff) {                                \
 126     if (_pctx->off < PRE##_BUFSZ)                                       \
 127       memset(_pctx->buf + _pctx->off, pad, PRE##_BUFSZ - _pctx->off);   \
 128     pre##_compress(_pctx, _pctx->buf);                                  \
 129     memset(_pctx->buf, pad, PRE##_BUFSZ - diff);                        \
 130   } else                                                                \
 131     memset(_pctx->buf + _pctx->off, pad,                                \
 132            PRE##_BUFSZ - _pctx->off - diff);                            \
 133 } while (0)
 134
 135 /* --- @HASH_MD5STRENGTH@ --- *
 136  *
 137  * Arguments:   @PRE@, @pre@ = prefixes for hash-specific definitions
 138  *              @ictx@ = pointer to context block for the hash
 139  *
 140  * Use:         Does MD5-style MD strengthening.  The data is terminated
 141  *              by a single set bit, padded with zero bits, and then a 64-
 142  *              bit length is written, little-end first.
 143  */
 144
 145 #define HASH_MD5STRENGTH(PRE, pre, ictx) do {                           \
 146   pre##_ctx *_mctx = (ictx);                                            \
 147   HASH_PAD(PRE, pre, _mctx, 0x80u, 0, 8);                               \
 148   STORE32_L(_mctx->buf + PRE##_BUFSZ - 8, _mctx->nl << 3);              \
 149   STORE32_L(_mctx->buf + PRE##_BUFSZ - 4,                               \
 150             (_mctx->nl >> 29) | (_mctx->nh << 3));                      \
 151   pre##_compress(_mctx, _mctx->buf);                                    \
 152 } while (0)
 153
 154 /* --- @HASH_TEST@ --- *
 155  *
 156  * Arguments:   @PRE@, @pre@ = prefixes for hash-specfic definitions
 157  *
 158  * Use:         Standard test rig for hash functions.
 159  */
 160
 161 #ifdef TEST_RIG
 162
 163 #include <mLib/quis.h>
 164 #include <mLib/testrig.h>
 165
 166 #define HASH_BUFLEN 100000
 167
 168 #define HASH_TEST(PRE, pre)                                             \
 169                                                                         \
 170 static int verify(dstr *v)                                              \
 171 {                                                                       \
 172   pre##_ctx ctx;                                                        \
 173   int ok = 1;                                                           \
 174   int i;                                                                \
 175   octet *p;                                                             \
 176   int szs[] = { 1, 7, 192, -1, 0 }, *ip;                                \
 177   size_t sz;                                                            \
 178   dstr d;                                                               \
 179                                                                         \
 180   dstr_create(&d);                                                      \
 181   dstr_ensure(&d, PRE##_HASHSZ);                                        \
 182   d.len = PRE##_HASHSZ;                                                 \
 183                                                                         \
 184   for (ip = szs; *ip; ip++) {                                           \
 185     i = *ip;                                                            \
 186     sz = v[0].len;                                                      \
 187     if (i == -1)                                                        \
 188       i = sz;                                                           \
 189     if (i > sz)                                                         \
 190       continue;                                                         \
 191     p = (octet *)v[0].buf;                                              \
 192     pre##_init(&ctx);                                                   \
 193     while (sz) {                                                        \
 194       if (i > sz)                                                       \
 195         i = sz;                                                         \
 196       pre##_hash(&ctx, p, i);                                           \
 197       p += i;                                                           \
 198       sz -= i;                                                          \
 199     }                                                                   \
 200     pre##_done(&ctx, d.buf);                                            \
 201     if (memcmp(d.buf, v[1].buf, PRE##_HASHSZ) != 0) {                   \
 202       printf("\nfail:\n\tstep = %i\n\tinput = `%s'\n\texpected = ",     \
 203              *ip, v[0].buf);                                            \
 204       type_hex.dump(&v[1], stdout);                                     \
 205       fputs("\n\tcomputed = ", stdout);                                 \
 206       type_hex.dump(&d, stdout);                                        \
 207       putchar('\n');                                                    \
 208       ok = 0;                                                           \
 209     }                                                                   \
 210   }                                                                     \
 211                                                                         \
 212   dstr_destroy(&d);                                                     \
 213   return (ok);                                                          \
 214 }                                                                       \
 215                                                                         \
 216 static int verifyrep(dstr *v)                                           \
 217 {                                                                       \
 218   pre##_ctx ctx;                                                        \
 219   size_t len = v[0].len;                                                \
 220   int n = *(int *)v[1].buf;                                             \
 221   int nd = 0;                                                           \
 222   int nn = len;                                                         \
 223   int ok = 1;                                                           \
 224   octet *p, *q;                                                         \
 225   dstr d = DSTR_INIT;                                                   \
 226                                                                         \
 227   while (nn < HASH_BUFLEN && (n & 1) == 0) { nd++; nn <<= 1; n >>= 1; } \
 228   p = xmalloc(nn);                                                      \
 229   memcpy(p, v[0].buf, len);                                             \
 230   q = p + len;                                                          \
 231   while (nd--) { memcpy(q, p, len); q += len; len <<= 1; }              \
 232                                                                         \
 233   dstr_ensure(&d, PRE##_HASHSZ);                                        \
 234   d.len = PRE##_HASHSZ;                                                 \
 235   pre##_init(&ctx);                                                     \
 236   while (n--) pre##_hash(&ctx, p, len);                                 \
 237   pre##_done(&ctx, d.buf);                                              \
 238                                                                         \
 239   if (memcmp(d.buf, v[2].buf, PRE##_HASHSZ) != 0) {                     \
 240     printf("\nfail:\n\tinput = `%s'\n\treps = `%i'\n\texpected = ",     \
 241              v[0].buf, *(int *)v[1].buf);                               \
 242     type_hex.dump(&v[2], stdout);                                       \
 243     fputs("\n\tcomputed = ", stdout);                                   \
 244     type_hex.dump(&d, stdout);                                          \
 245     putchar('\n');                                                      \
 246     ok = 0;                                                             \
 247   }                                                                     \
 248   xfree(p);                                                             \
 249   dstr_destroy(&d);                                                     \
 250   return (ok);                                                          \
 251 }                                                                       \
 252                                                                         \
 253 static test_chunk defs[] = {                                            \
 254   { #pre, verify, { &type_string, &type_hex, 0 } },                     \
 255   { #pre "-rep", verifyrep,                                             \
 256     { &type_string, &type_int, &type_hex, 0 } },                        \
 257   { 0, 0, { 0 } }                                                       \
 258 };                                                                      \
 259                                                                         \
 260 int main(int argc, char *argv[])                                        \
 261 {                                                                       \
 262   ego(argv[0]);                                                         \
 263   test_run(argc, argv, defs, SRCDIR"/t/" #pre);                         \
 264   return (0);                                                           \
 265 }
 266
 267 #else
 268 #  define HASH_TEST(PRE, pre)
 269 #endif
 270
 271 /*----- That's all, folks -------------------------------------------------*/
 272
 273 #ifdef __cplusplus
 274   }
 275 #endif
 276
 277 #endif