Fix uninitialized memory read

This commit is contained in:
Nick Terrell
2016-11-14 13:57:05 -08:00
parent cdff19c4b3
commit 24701de877
7 changed files with 46 additions and 67 deletions
+6 -9
View File
@@ -2706,7 +2706,6 @@ struct ZSTDv04_Dctx_s
blockType_t bType;
ZSTD_dStage stage;
const BYTE* litPtr;
size_t litBufSize;
size_t litSize;
BYTE litBuffer[BLOCKSIZE + 8 /* margin for wildcopy */];
BYTE headerBuffer[ZSTD_frameHeaderSize_max];
@@ -2847,8 +2846,8 @@ static size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
size_t litSize = BLOCKSIZE;
const size_t readSize = ZSTD_decompressLiterals(dctx->litBuffer, &litSize, src, srcSize);
dctx->litPtr = dctx->litBuffer;
dctx->litBufSize = BLOCKSIZE+8;
dctx->litSize = litSize;
memset(dctx->litBuffer + dctx->litSize, 0, 8);
return readSize; /* works if it's an error too */
}
case IS_RAW:
@@ -2859,13 +2858,12 @@ static size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
if (litSize > srcSize-3) return ERROR(corruption_detected);
memcpy(dctx->litBuffer, istart, litSize);
dctx->litPtr = dctx->litBuffer;
dctx->litBufSize = BLOCKSIZE+8;
dctx->litSize = litSize;
memset(dctx->litBuffer + dctx->litSize, 0, 8);
return litSize+3;
}
/* direct reference into compressed stream */
dctx->litPtr = istart+3;
dctx->litBufSize = srcSize-3;
dctx->litSize = litSize;
return litSize+3; }
case IS_RLE:
@@ -2874,8 +2872,8 @@ static size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
if (litSize > BLOCKSIZE) return ERROR(corruption_detected);
memset(dctx->litBuffer, istart[3], litSize);
dctx->litPtr = dctx->litBuffer;
dctx->litBufSize = BLOCKSIZE+8;
dctx->litSize = litSize;
memset(dctx->litBuffer + dctx->litSize, 0, 8);
return 4;
}
default:
@@ -3069,7 +3067,7 @@ static void ZSTD_decodeSequence(seq_t* seq, seqState_t* seqState)
static size_t ZSTD_execSequence(BYTE* op,
BYTE* const oend, seq_t sequence,
const BYTE** litPtr, const BYTE* const litLimit_8,
const BYTE** litPtr, const BYTE* const litLimit,
const BYTE* const base, const BYTE* const vBase, const BYTE* const dictEnd)
{
static const int dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 }; /* added */
@@ -3084,7 +3082,7 @@ static size_t ZSTD_execSequence(BYTE* op,
/* check */
if (oLitEnd > oend_8) return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of 8 from oend */
if (oMatchEnd > oend) return ERROR(dstSize_tooSmall); /* overwrite beyond dst buffer */
if (litEnd > litLimit_8) return ERROR(corruption_detected); /* risk read beyond lit buffer */
if (litEnd > litLimit) return ERROR(corruption_detected); /* risk read beyond lit buffer */
/* copy Literals */
ZSTD_wildcopy(op, *litPtr, sequence.litLength); /* note : oLitEnd <= oend-8 : no risk of overwrite beyond oend */
@@ -3167,7 +3165,6 @@ static size_t ZSTD_decompressSequences(
BYTE* const oend = ostart + maxDstSize;
size_t errorCode, dumpsLength;
const BYTE* litPtr = dctx->litPtr;
const BYTE* const litLimit_8 = litPtr + dctx->litBufSize - 8;
const BYTE* const litEnd = litPtr + dctx->litSize;
int nbSeq;
const BYTE* dumps;
@@ -3206,7 +3203,7 @@ static size_t ZSTD_decompressSequences(
size_t oneSeqSize;
nbSeq--;
ZSTD_decodeSequence(&sequence, &seqState);
oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litLimit_8, base, vBase, dictEnd);
oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litEnd, base, vBase, dictEnd);
if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
op += oneSeqSize;
}