module/zstd/lib/decompress/zstd_ddict.c

   1 /*
   2  * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under both the BSD-style license (found in the
   6  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
   7  * in the COPYING file in the root directory of this source tree).
   8  * You may select, at your option, one of the above-listed licenses.
   9  */
  10
  11 /* zstd_ddict.c :
  12  * concentrates all logic that needs to know the internals of ZSTD_DDict object */
  13
  14 /*-*******************************************************
  15 *  Dependencies
  16 *********************************************************/
  17 #include <string.h>      /* memcpy, memmove, memset */
  18 #include "../common/cpu.h"         /* bmi2 */
  19 #include "../common/mem.h"         /* low level memory routines */
  20 #define FSE_STATIC_LINKING_ONLY
  21 #include "../common/fse.h"
  22 #define HUF_STATIC_LINKING_ONLY
  23 #include "../common/huf.h"
  24 #include "zstd_decompress_internal.h"
  25 #include "zstd_ddict.h"
  26
  27 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
  28 #  include "../legacy/zstd_legacy.h"
  29 #endif
  30
  31
  32
  33 /*-*******************************************************
  34 *  Types
  35 *********************************************************/
  36 struct ZSTD_DDict_s {
  37     void* dictBuffer;
  38     const void* dictContent;
  39     size_t dictSize;
  40     ZSTD_entropyDTables_t entropy;
  41     U32 dictID;
  42     U32 entropyPresent;
  43     ZSTD_customMem cMem;
  44 };  /* typedef'd to ZSTD_DDict within "zstd.h" */
  45
  46 const void* ZSTD_DDict_dictContent(const ZSTD_DDict* ddict)
  47 {
  48     assert(ddict != NULL);
  49     return ddict->dictContent;
  50 }
  51
  52 size_t ZSTD_DDict_dictSize(const ZSTD_DDict* ddict)
  53 {
  54     assert(ddict != NULL);
  55     return ddict->dictSize;
  56 }
  57
  58 void ZSTD_copyDDictParameters(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict)
  59 {
  60     DEBUGLOG(4, "ZSTD_copyDDictParameters");
  61     assert(dctx != NULL);
  62     assert(ddict != NULL);
  63     dctx->dictID = ddict->dictID;
  64     dctx->prefixStart = ddict->dictContent;
  65     dctx->virtualStart = ddict->dictContent;
  66     dctx->dictEnd = (const BYTE*)ddict->dictContent + ddict->dictSize;
  67     dctx->previousDstEnd = dctx->dictEnd;
  68 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
  69     dctx->dictContentBeginForFuzzing = dctx->prefixStart;
  70     dctx->dictContentEndForFuzzing = dctx->previousDstEnd;
  71 #endif
  72     if (ddict->entropyPresent) {
  73         dctx->litEntropy = 1;
  74         dctx->fseEntropy = 1;
  75         dctx->LLTptr = ddict->entropy.LLTable;
  76         dctx->MLTptr = ddict->entropy.MLTable;
  77         dctx->OFTptr = ddict->entropy.OFTable;
  78         dctx->HUFptr = ddict->entropy.hufTable;
  79         dctx->entropy.rep[0] = ddict->entropy.rep[0];
  80         dctx->entropy.rep[1] = ddict->entropy.rep[1];
  81         dctx->entropy.rep[2] = ddict->entropy.rep[2];
  82     } else {
  83         dctx->litEntropy = 0;
  84         dctx->fseEntropy = 0;
  85     }
  86 }
  87
  88
  89 static size_t
  90 ZSTD_loadEntropy_intoDDict(ZSTD_DDict* ddict,
  91                            ZSTD_dictContentType_e dictContentType)
  92 {
  93     ddict->dictID = 0;
  94     ddict->entropyPresent = 0;
  95     if (dictContentType == ZSTD_dct_rawContent) return 0;
  96
  97     if (ddict->dictSize < 8) {
  98         if (dictContentType == ZSTD_dct_fullDict)
  99             return ERROR(dictionary_corrupted);   /* only accept specified dictionaries */
 100         return 0;   /* pure content mode */
 101     }
 102     {   U32 const magic = MEM_readLE32(ddict->dictContent);
 103         if (magic != ZSTD_MAGIC_DICTIONARY) {
 104             if (dictContentType == ZSTD_dct_fullDict)
 105                 return ERROR(dictionary_corrupted);   /* only accept specified dictionaries */
 106             return 0;   /* pure content mode */
 107         }
 108     }
 109     ddict->dictID = MEM_readLE32((const char*)ddict->dictContent + ZSTD_FRAMEIDSIZE);
 110
 111     /* load entropy tables */
 112     RETURN_ERROR_IF(ZSTD_isError(ZSTD_loadDEntropy(
 113             &ddict->entropy, ddict->dictContent, ddict->dictSize)),
 114         dictionary_corrupted, "");
 115     ddict->entropyPresent = 1;
 116     return 0;
 117 }
 118
 119
 120 static size_t ZSTD_initDDict_internal(ZSTD_DDict* ddict,
 121                                       const void* dict, size_t dictSize,
 122                                       ZSTD_dictLoadMethod_e dictLoadMethod,
 123                                       ZSTD_dictContentType_e dictContentType)
 124 {
 125     if ((dictLoadMethod == ZSTD_dlm_byRef) || (!dict) || (!dictSize)) {
 126         ddict->dictBuffer = NULL;
 127         ddict->dictContent = dict;
 128         if (!dict) dictSize = 0;
 129     } else {
 130         void* const internalBuffer = ZSTD_malloc(dictSize, ddict->cMem);
 131         ddict->dictBuffer = internalBuffer;
 132         ddict->dictContent = internalBuffer;
 133         if (!internalBuffer) return ERROR(memory_allocation);
 134         memcpy(internalBuffer, dict, dictSize);
 135     }
 136     ddict->dictSize = dictSize;
 137     ddict->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001);  /* cover both little and big endian */
 138
 139     /* parse dictionary content */
 140     FORWARD_IF_ERROR( ZSTD_loadEntropy_intoDDict(ddict, dictContentType) , "");
 141
 142     return 0;
 143 }
 144
 145 ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize,
 146                                       ZSTD_dictLoadMethod_e dictLoadMethod,
 147                                       ZSTD_dictContentType_e dictContentType,
 148                                       ZSTD_customMem customMem)
 149 {
 150     if (!customMem.customAlloc ^ !customMem.customFree) return NULL;
 151
 152     {   ZSTD_DDict* const ddict = (ZSTD_DDict*) ZSTD_malloc(sizeof(ZSTD_DDict), customMem);
 153         if (ddict == NULL) return NULL;
 154         ddict->cMem = customMem;
 155         {   size_t const initResult = ZSTD_initDDict_internal(ddict,
 156                                             dict, dictSize,
 157                                             dictLoadMethod, dictContentType);
 158             if (ZSTD_isError(initResult)) {
 159                 ZSTD_freeDDict(ddict);
 160                 return NULL;
 161         }   }
 162         return ddict;
 163     }
 164 }
 165
 166 /*! ZSTD_createDDict() :
 167 *   Create a digested dictionary, to start decompression without startup delay.
 168 *   `dict` content is copied inside DDict.
 169 *   Consequently, `dict` can be released after `ZSTD_DDict` creation */
 170 ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize)
 171 {
 172     ZSTD_customMem const allocator = { NULL, NULL, NULL };
 173     return ZSTD_createDDict_advanced(dict, dictSize, ZSTD_dlm_byCopy, ZSTD_dct_auto, allocator);
 174 }
 175
 176 /*! ZSTD_createDDict_byReference() :
 177  *  Create a digested dictionary, to start decompression without startup delay.
 178  *  Dictionary content is simply referenced, it will be accessed during decompression.
 179  *  Warning : dictBuffer must outlive DDict (DDict must be freed before dictBuffer) */
 180 ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize)
 181 {
 182     ZSTD_customMem const allocator = { NULL, NULL, NULL };
 183     return ZSTD_createDDict_advanced(dictBuffer, dictSize, ZSTD_dlm_byRef, ZSTD_dct_auto, allocator);
 184 }
 185
 186
 187 const ZSTD_DDict* ZSTD_initStaticDDict(
 188                                 void* sBuffer, size_t sBufferSize,
 189                                 const void* dict, size_t dictSize,
 190                                 ZSTD_dictLoadMethod_e dictLoadMethod,
 191                                 ZSTD_dictContentType_e dictContentType)
 192 {
 193     size_t const neededSpace = sizeof(ZSTD_DDict)
 194                              + (dictLoadMethod == ZSTD_dlm_byRef ? 0 : dictSize);
 195     ZSTD_DDict* const ddict = (ZSTD_DDict*)sBuffer;
 196     assert(sBuffer != NULL);
 197     assert(dict != NULL);
 198     if ((size_t)sBuffer & 7) return NULL;   /* 8-aligned */
 199     if (sBufferSize < neededSpace) return NULL;
 200     if (dictLoadMethod == ZSTD_dlm_byCopy) {
 201         memcpy(ddict+1, dict, dictSize);  /* local copy */
 202         dict = ddict+1;
 203     }
 204     if (ZSTD_isError( ZSTD_initDDict_internal(ddict,
 205                                               dict, dictSize,
 206                                               ZSTD_dlm_byRef, dictContentType) ))
 207         return NULL;
 208     return ddict;
 209 }
 210
 211
 212 size_t ZSTD_freeDDict(ZSTD_DDict* ddict)
 213 {
 214     if (ddict==NULL) return 0;   /* support free on NULL */
 215     {   ZSTD_customMem const cMem = ddict->cMem;
 216         ZSTD_free(ddict->dictBuffer, cMem);
 217         ZSTD_free(ddict, cMem);
 218         return 0;
 219     }
 220 }
 221
 222 /*! ZSTD_estimateDDictSize() :
 223  *  Estimate amount of memory that will be needed to create a dictionary for decompression.
 224  *  Note : dictionary created by reference using ZSTD_dlm_byRef are smaller */
 225 size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod)
 226 {
 227     return sizeof(ZSTD_DDict) + (dictLoadMethod == ZSTD_dlm_byRef ? 0 : dictSize);
 228 }
 229
 230 size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict)
 231 {
 232     if (ddict==NULL) return 0;   /* support sizeof on NULL */
 233     return sizeof(*ddict) + (ddict->dictBuffer ? ddict->dictSize : 0) ;
 234 }
 235
 236 /*! ZSTD_getDictID_fromDDict() :
 237  *  Provides the dictID of the dictionary loaded into `ddict`.
 238  *  If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
 239  *  Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */
 240 unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict)
 241 {
 242     if (ddict==NULL) return 0;
 243     return ZSTD_getDictID_fromDict(ddict->dictContent, ddict->dictSize);
 244 }