lib/gnutls_compress.c

   1 /*
   2  * Copyright (C) 2000-2012 Free Software Foundation, Inc.
   3  *
   4  * Author: Nikos Mavrogiannopoulos
   5  *
   6  * This file is part of GnuTLS.
   7  *
   8  * The GnuTLS is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public License
  10  * as published by the Free Software Foundation; either version 3 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public License
  19  * along with this program.  If not, see <http://www.gnu.org/licenses/>
  20  *
  21  */
  22
  23 /* This file contains the functions which convert the TLS plaintext
  24  * packet to TLS compressed packet.
  25  */
  26
  27 #include "gnutls_int.h"
  28 #include "gnutls_compress.h"
  29 #include "gnutls_errors.h"
  30 #include "gnutls_constate.h"
  31 #include <algorithms.h>
  32 #include <gnutls/gnutls.h>
  33
  34 /* Compression Section */
  35 #define GNUTLS_COMPRESSION_ENTRY(name, id, wb, ml, cl)  \
  36   { #name, name, id, wb, ml, cl}
  37
  38
  39 #define MAX_COMP_METHODS 5
  40 const int _gnutls_comp_algorithms_size = MAX_COMP_METHODS;
  41
  42 gnutls_compression_entry _gnutls_compression_algorithms[MAX_COMP_METHODS] = {
  43   GNUTLS_COMPRESSION_ENTRY (GNUTLS_COMP_NULL, 0x00, 0, 0, 0),
  44 #ifdef HAVE_LIBZ
  45   /* draft-ietf-tls-compression-02 */
  46   GNUTLS_COMPRESSION_ENTRY (GNUTLS_COMP_DEFLATE, 0x01, 15, 8, 3),
  47 #endif
  48   {0, 0, 0, 0, 0, 0}
  49 };
  50
  51 static const gnutls_compression_method_t supported_compressions[] = {
  52 #ifdef HAVE_LIBZ
  53   GNUTLS_COMP_DEFLATE,
  54 #endif
  55   GNUTLS_COMP_NULL,
  56   0
  57 };
  58
  59 #define GNUTLS_COMPRESSION_LOOP(b)         \
  60   const gnutls_compression_entry *p;                                    \
  61   for(p = _gnutls_compression_algorithms; p->name != NULL; p++) { b ; }
  62 #define GNUTLS_COMPRESSION_ALG_LOOP(a)                                  \
  63   GNUTLS_COMPRESSION_LOOP( if(p->id == algorithm) { a; break; } )
  64 #define GNUTLS_COMPRESSION_ALG_LOOP_NUM(a)                              \
  65   GNUTLS_COMPRESSION_LOOP( if(p->num == num) { a; break; } )
  66
  67 /* Compression Functions */
  68
  69 /**
  70  * gnutls_compression_get_name:
  71  * @algorithm: is a Compression algorithm
  72  *
  73  * Convert a #gnutls_compression_method_t value to a string.
  74  *
  75  * Returns: a pointer to a string that contains the name of the
  76  *   specified compression algorithm, or %NULL.
  77  **/
  78 const char *
  79 gnutls_compression_get_name (gnutls_compression_method_t algorithm)
  80 {
  81   const char *ret = NULL;
  82
  83   /* avoid prefix */
  84   GNUTLS_COMPRESSION_ALG_LOOP (ret = p->name + sizeof ("GNUTLS_COMP_") - 1);
  85
  86   return ret;
  87 }
  88
  89 /**
  90  * gnutls_compression_get_id:
  91  * @name: is a compression method name
  92  *
  93  * The names are compared in a case insensitive way.
  94  *
  95  * Returns: an id of the specified in a string compression method, or
  96  *   %GNUTLS_COMP_UNKNOWN on error.
  97  **/
  98 gnutls_compression_method_t
  99 gnutls_compression_get_id (const char *name)
 100 {
 101   gnutls_compression_method_t ret = GNUTLS_COMP_UNKNOWN;
 102
 103   GNUTLS_COMPRESSION_LOOP (if
 104                            (strcasecmp
 105                             (p->name + sizeof ("GNUTLS_COMP_") - 1,
 106                              name) == 0) ret = p->id);
 107
 108   return ret;
 109 }
 110
 111 /**
 112  * gnutls_compression_list:
 113  *
 114  * Get a list of compression methods.
 115  *
 116  * Returns: a zero-terminated list of #gnutls_compression_method_t
 117  *   integers indicating the available compression methods.
 118  **/
 119 const gnutls_compression_method_t *
 120 gnutls_compression_list (void)
 121 {
 122   return supported_compressions;
 123 }
 124
 125 /* return the tls number of the specified algorithm */
 126 int
 127 _gnutls_compression_get_num (gnutls_compression_method_t algorithm)
 128 {
 129   int ret = -1;
 130
 131   /* avoid prefix */
 132   GNUTLS_COMPRESSION_ALG_LOOP (ret = p->num);
 133
 134   return ret;
 135 }
 136
 137 #ifdef HAVE_LIBZ
 138
 139 static int
 140 get_wbits (gnutls_compression_method_t algorithm)
 141 {
 142   int ret = -1;
 143   /* avoid prefix */
 144   GNUTLS_COMPRESSION_ALG_LOOP (ret = p->window_bits);
 145   return ret;
 146 }
 147
 148 static int
 149 get_mem_level (gnutls_compression_method_t algorithm)
 150 {
 151   int ret = -1;
 152   /* avoid prefix */
 153   GNUTLS_COMPRESSION_ALG_LOOP (ret = p->mem_level);
 154   return ret;
 155 }
 156
 157 static int
 158 get_comp_level (gnutls_compression_method_t algorithm)
 159 {
 160   int ret = -1;
 161   /* avoid prefix */
 162   GNUTLS_COMPRESSION_ALG_LOOP (ret = p->comp_level);
 163   return ret;
 164 }
 165
 166 #endif
 167
 168 /* returns the gnutls internal ID of the TLS compression
 169  * method num
 170  */
 171 gnutls_compression_method_t
 172 _gnutls_compression_get_id (int num)
 173 {
 174   gnutls_compression_method_t ret = -1;
 175
 176   /* avoid prefix */
 177   GNUTLS_COMPRESSION_ALG_LOOP_NUM (ret = p->id);
 178
 179   return ret;
 180 }
 181
 182 int
 183 _gnutls_compression_is_ok (gnutls_compression_method_t algorithm)
 184 {
 185   ssize_t ret = -1;
 186   GNUTLS_COMPRESSION_ALG_LOOP (ret = p->id);
 187   if (ret >= 0)
 188     ret = 0;
 189   else
 190     ret = 1;
 191   return ret;
 192 }
 193
 194
 195
 196 /* For compression  */
 197
 198 #define MIN_PRIVATE_COMP_ALGO 0xEF
 199
 200 /* returns the TLS numbers of the compression methods we support
 201  */
 202 #define SUPPORTED_COMPRESSION_METHODS session->internals.priorities.compression.algorithms
 203 int
 204 _gnutls_supported_compression_methods (gnutls_session_t session,
 205                                        uint8_t * comp, size_t comp_size)
 206 {
 207   unsigned int i, j;
 208
 209   if (comp_size < SUPPORTED_COMPRESSION_METHODS)
 210     return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
 211
 212   for (i = j = 0; i < SUPPORTED_COMPRESSION_METHODS; i++)
 213     {
 214       int tmp =
 215         _gnutls_compression_get_num (session->internals.
 216                                      priorities.compression.priority[i]);
 217
 218       /* remove private compression algorithms, if requested.
 219        */
 220       if (tmp == -1 || (tmp >= MIN_PRIVATE_COMP_ALGO &&
 221                         session->internals.enable_private == 0))
 222         {
 223           gnutls_assert ();
 224           continue;
 225         }
 226
 227       comp[j] = (uint8_t) tmp;
 228       j++;
 229     }
 230
 231   if (j == 0)
 232     {
 233       gnutls_assert ();
 234       return GNUTLS_E_NO_COMPRESSION_ALGORITHMS;
 235     }
 236   return j;
 237 }
 238
 239
 240 /* The flag d is the direction (compress, decompress). Non zero is
 241  * decompress.
 242  */
 243 int _gnutls_comp_init (comp_hd_st* handle, gnutls_compression_method_t method, int d)
 244 {
 245   handle->algo = method;
 246   handle->handle = NULL;
 247
 248   switch (method)
 249     {
 250     case GNUTLS_COMP_DEFLATE:
 251 #ifdef HAVE_LIBZ
 252       {
 253         int window_bits, mem_level;
 254         int comp_level;
 255         z_stream *zhandle;
 256         int err;
 257
 258         window_bits = get_wbits (method);
 259         mem_level = get_mem_level (method);
 260         comp_level = get_comp_level (method);
 261
 262         handle->handle = gnutls_malloc (sizeof (z_stream));
 263         if (handle->handle == NULL)
 264           return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
 265
 266         zhandle = handle->handle;
 267
 268         zhandle->zalloc = (alloc_func) 0;
 269         zhandle->zfree = (free_func) 0;
 270         zhandle->opaque = (voidpf) 0;
 271
 272         if (d)
 273           err = inflateInit2 (zhandle, window_bits);
 274         else
 275           {
 276             err = deflateInit2 (zhandle,
 277                                 comp_level, Z_DEFLATED,
 278                                 window_bits, mem_level, Z_DEFAULT_STRATEGY);
 279           }
 280         if (err != Z_OK)
 281           {
 282             gnutls_assert ();
 283             gnutls_free (handle->handle);
 284             return GNUTLS_E_COMPRESSION_FAILED;
 285           }
 286       }
 287       break;
 288 #endif
 289     case GNUTLS_COMP_NULL:
 290     case GNUTLS_COMP_UNKNOWN:
 291       break;
 292     default:
 293       return GNUTLS_E_UNKNOWN_COMPRESSION_ALGORITHM;
 294     }
 295
 296   return 0;
 297 }
 298
 299 /* The flag d is the direction (compress, decompress). Non zero is
 300  * decompress.
 301  */
 302 void
 303 _gnutls_comp_deinit (comp_hd_st* handle, int d)
 304 {
 305   if (handle != NULL)
 306     {
 307       switch (handle->algo)
 308         {
 309 #ifdef HAVE_LIBZ
 310         case GNUTLS_COMP_DEFLATE:
 311           {
 312             if (d)
 313               inflateEnd (handle->handle);
 314             else
 315               deflateEnd (handle->handle);
 316             break;
 317           }
 318 #endif
 319         default:
 320           break;
 321         }
 322       gnutls_free (handle->handle);
 323       handle->handle = NULL;
 324     }
 325 }
 326
 327 /* These functions are memory consuming
 328  */
 329
 330 int
 331 _gnutls_compress (comp_hd_st *handle, const uint8_t * plain,
 332                   size_t plain_size, uint8_t * compressed,
 333                   size_t max_comp_size, unsigned int stateless)
 334 {
 335   int compressed_size = GNUTLS_E_COMPRESSION_FAILED;
 336
 337   /* NULL compression is not handled here
 338    */
 339   if (handle == NULL)
 340     {
 341       gnutls_assert ();
 342       return GNUTLS_E_INTERNAL_ERROR;
 343     }
 344
 345   switch (handle->algo)
 346     {
 347 #ifdef HAVE_LIBZ
 348     case GNUTLS_COMP_DEFLATE:
 349       {
 350         z_stream *zhandle;
 351         int err;
 352         int type;
 353
 354         if (stateless)
 355           {
 356             type = Z_FULL_FLUSH;
 357           }
 358         else
 359           type = Z_SYNC_FLUSH;
 360
 361         zhandle = handle->handle;
 362
 363         zhandle->next_in = (Bytef *) plain;
 364         zhandle->avail_in = plain_size;
 365         zhandle->next_out = (Bytef *) compressed;
 366         zhandle->avail_out = max_comp_size;
 367
 368         err = deflate (zhandle, type);
 369         if (err != Z_OK || zhandle->avail_in != 0)
 370           return gnutls_assert_val(GNUTLS_E_COMPRESSION_FAILED);
 371
 372
 373         compressed_size = max_comp_size - zhandle->avail_out;
 374         break;
 375       }
 376 #endif
 377     default:
 378       gnutls_assert ();
 379       return GNUTLS_E_INTERNAL_ERROR;
 380     }                           /* switch */
 381
 382 #ifdef COMPRESSION_DEBUG
 383   _gnutls_debug_log ("Compression ratio: %f\n",
 384                      (float) ((float) compressed_size / (float) plain_size));
 385 #endif
 386
 387   return compressed_size;
 388 }
 389
 390
 391
 392 int
 393 _gnutls_decompress (comp_hd_st *handle, uint8_t * compressed,
 394                     size_t compressed_size, uint8_t * plain,
 395                     size_t max_plain_size)
 396 {
 397   int plain_size = GNUTLS_E_DECOMPRESSION_FAILED;
 398
 399   if (compressed_size > max_plain_size + EXTRA_COMP_SIZE)
 400     {
 401       gnutls_assert ();
 402       return GNUTLS_E_DECOMPRESSION_FAILED;
 403     }
 404
 405   /* NULL compression is not handled here
 406    */
 407
 408   if (handle == NULL)
 409     {
 410       gnutls_assert ();
 411       return GNUTLS_E_INTERNAL_ERROR;
 412     }
 413
 414   switch (handle->algo)
 415     {
 416 #ifdef HAVE_LIBZ
 417     case GNUTLS_COMP_DEFLATE:
 418       {
 419         z_stream *zhandle;
 420         int err;
 421
 422         zhandle = handle->handle;
 423
 424         zhandle->next_in = (Bytef *) compressed;
 425         zhandle->avail_in = compressed_size;
 426
 427         zhandle->next_out = (Bytef *) plain;
 428         zhandle->avail_out = max_plain_size;
 429         err = inflate (zhandle, Z_SYNC_FLUSH);
 430
 431         if (err != Z_OK)
 432           return gnutls_assert_val(GNUTLS_E_DECOMPRESSION_FAILED);
 433
 434         plain_size = max_plain_size - zhandle->avail_out;
 435         break;
 436       }
 437 #endif
 438     default:
 439       gnutls_assert ();
 440       return GNUTLS_E_INTERNAL_ERROR;
 441     }                           /* switch */
 442
 443   return plain_size;
 444 }