protect 32-bits mode

lib/bitstream.h

@@ -208,7 +208,7 @@ MEM_STATIC void BIT_flushBitsFast(BIT_CStream_t* bitC)
     MEM_writeLEST(bitC->ptr, bitC->bitContainer);
     bitC->ptr += nbBytes;
     bitC->bitPos &= 7;
-    bitC->bitContainer >>= nbBytes*8;
+    bitC->bitContainer >>= nbBytes*8;   /* if bitPos >= sizeof(bitContainer)*8 --> undefined behavior */
 }
 
 MEM_STATIC void BIT_flushBits(BIT_CStream_t* bitC)
@@ -218,7 +218,7 @@ MEM_STATIC void BIT_flushBits(BIT_CStream_t* bitC)
     bitC->ptr += nbBytes;
     if (bitC->ptr > bitC->endPtr) bitC->ptr = bitC->endPtr;
     bitC->bitPos &= 7;
-    bitC->bitContainer >>= nbBytes*8;
+    bitC->bitContainer >>= nbBytes*8;   /* if bitPos >= sizeof(bitContainer)*8 --> undefined behavior */
 }
 
 /*! BIT_closeCStream

lib/error.h

@@ -68,10 +68,10 @@ extern "C" {
 
 #define ERROR_LIST(ITEM) \
         ITEM(PREFIX(No_Error)) ITEM(PREFIX(GENERIC)) \
-        ITEM(PREFIX(mode_unsupported)) ITEM(PREFIX(init_missing))\
-        ITEM(PREFIX(memory_allocation)) \
+        ITEM(PREFIX(prefix_unknown)) ITEM(PREFIX(frameParameter_unsupportedBy32bitsImplementation)) \
+        ITEM(PREFIX(init_missing)) ITEM(PREFIX(memory_allocation)) \
         ITEM(PREFIX(dstSize_tooSmall)) ITEM(PREFIX(srcSize_wrong)) \
-        ITEM(PREFIX(prefix_unknown)) ITEM(PREFIX(corruption_detected)) \
+        ITEM(PREFIX(corruption_detected)) \
         ITEM(PREFIX(tableLog_tooLarge)) ITEM(PREFIX(maxSymbolValue_tooLarge)) ITEM(PREFIX(maxSymbolValue_tooSmall)) \
         ITEM(PREFIX(maxCode))
 

lib/zstd_buffered.h

@@ -83,6 +83,7 @@ size_t ZBUFF_compressEnd(ZBUFF_CCtx* cctx, void* dst, size_t* maxDstSizePtr);
 *
 *  ZBUFF_compressEnd() instructs to finish a frame.
 *  It will perform a flush and write frame epilogue.
+*  Note that the epilogue is necessary for decoders to consider a frame completed.
 *  Similar to ZBUFF_compressFlush(), it may not be able to output the entire internal buffer content if *maxDstSizePtr is too small.
 *  In which case, call again ZBUFF_compressFlush() to complete the flush.
 *  @return : nb of bytes still present into internal buffer (0 if it's empty)

lib/zstd_compress.c

@@ -143,6 +143,7 @@ void ZSTD_validateParams(ZSTD_parameters* params)
     const U32 btPlus = (params->strategy == ZSTD_btlazy2);
 
     /* validate params */
+    if (MEM_32bits()) if (params->windowLog > 25) params->windowLog = 25;   /* 32 bits mode cannot flush > 24 bits */
     if (params->windowLog   > ZSTD_WINDOWLOG_MAX) params->windowLog = ZSTD_WINDOWLOG_MAX;
     if (params->windowLog   < ZSTD_WINDOWLOG_MIN) params->windowLog = ZSTD_WINDOWLOG_MIN;
 
@@ -153,7 +154,7 @@ void ZSTD_validateParams(ZSTD_parameters* params)
         if (params->windowLog > srcLog) params->windowLog = srcLog;
     }
 
-    if (params->windowLog < ZSTD_WINDOWLOG_ABSOLUTEMIN) params->windowLog = ZSTD_WINDOWLOG_ABSOLUTEMIN;  /* required for frame header */
+    if (params->windowLog   < ZSTD_WINDOWLOG_ABSOLUTEMIN) params->windowLog = ZSTD_WINDOWLOG_ABSOLUTEMIN;  /* required for frame header */
     if (params->contentLog  > params->windowLog+btPlus) params->contentLog = params->windowLog+btPlus;   /* <= ZSTD_CONTENTLOG_MAX */
     if (params->contentLog  < ZSTD_CONTENTLOG_MIN) params->contentLog = ZSTD_CONTENTLOG_MIN;
     if (params->hashLog     > ZSTD_HASHLOG_MAX) params->hashLog = ZSTD_HASHLOG_MAX;

lib/zstd_decompress.c

@@ -204,8 +204,11 @@ size_t ZSTD_getFrameParams(ZSTD_parameters* params, const void* src, size_t srcS
 *   @return : 0, or an error code, which can be tested using ZSTD_isError() */
 static size_t ZSTD_decodeFrameHeader_Part2(ZSTD_DCtx* zc, const void* src, size_t srcSize)
 {
+    size_t result;
     if (srcSize != zc->headerSize) return ERROR(srcSize_wrong);
-    return ZSTD_getFrameParams(&(zc->params), src, srcSize);
+    result = ZSTD_getFrameParams(&(zc->params), src, srcSize);
+    if ((MEM_32bits()) && (zc->params.windowLog > 25)) return ERROR(frameParameter_unsupportedBy32bitsImplementation);
+    return result;
 }