AuroraMiddleware/lz4
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

fix matchIndex overflow

Browse Source 
can happen with dictCtx
This commit is contained in:
Yann Collet 2018-04-17 15:29:17 -07:00
parent ce78d10c1f
commit 1520642183
1 changed files with 4 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
lib/lz4.c
View File

@ -758,9 +758,9 @@ LZ4_FORCE_INLINE int LZ4_compress_generic(
forwardH = LZ4_hashPosition(forwardIp, tableType); forwardH = LZ4_hashPosition(forwardIp, tableType);
LZ4_putIndexOnHash(current, h, cctx->hashTable, tableType); LZ4_putIndexOnHash(current, h, cctx->hashTable, tableType);
if ((dictIssue == dictSmall) && (matchIndex < prefixIdxLimit)) continue; /* match outside of valid area */ if ((dictIssue == dictSmall) && (matchIndex < prefixIdxLimit)) continue; /* match outside of valid area */
if ((tableType != byU16) && (matchIndex+MAX_DISTANCE < current)) continue; /* too far */ if ((tableType != byU16) && (current - matchIndex > MAX_DISTANCE)) continue; /* too far - note: works even if matchIndex overflows */
if (tableType == byU16) assert((current - matchIndex) <= MAX_DISTANCE); /* too_far presumed impossible with byU16 */ if (tableType == byU16) assert((current - matchIndex) <= MAX_DISTANCE); /* too_far presumed impossible with byU16 */
if (LZ4_read32(match) == LZ4_read32(ip)) { if (LZ4_read32(match) == LZ4_read32(ip)) {
if (maybe_extMem) offset = current - matchIndex; if (maybe_extMem) offset = current - matchIndex;
@ -861,7 +861,6 @@ _next_match:
/* Fill table */ /* Fill table */
LZ4_putPosition(ip-2, cctx->hashTable, tableType, base); LZ4_putPosition(ip-2, cctx->hashTable, tableType, base);
#if 1
/* Test next position */ /* Test next position */
if (tableType == byPtr) { if (tableType == byPtr) {
@ -901,7 +900,7 @@ _next_match:
} }
LZ4_putIndexOnHash(current, h, cctx->hashTable, tableType); LZ4_putIndexOnHash(current, h, cctx->hashTable, tableType);
if ( ((dictIssue==dictSmall) ? (matchIndex >= prefixIdxLimit) : 1) if ( ((dictIssue==dictSmall) ? (matchIndex >= prefixIdxLimit) : 1)
&& ((tableType==byU16) ? 1 : (matchIndex+MAX_DISTANCE >= current)) && ((tableType==byU16) ? 1 : (current - matchIndex <= MAX_DISTANCE))
&& (LZ4_read32(match) == LZ4_read32(ip)) ) { && (LZ4_read32(match) == LZ4_read32(ip)) ) {
token=op++; token=op++;
*token=0; *token=0;
@ -914,13 +913,6 @@ _next_match:
/* Prepare next loop */ /* Prepare next loop */
forwardH = LZ4_hashPosition(++ip, tableType); forwardH = LZ4_hashPosition(++ip, tableType);
#else
/* Prepare next loop */
forwardH = LZ4_hashPosition(ip, tableType);
#endif
} }
_last_literals: _last_literals: