silence msan warning when offset==0

This commit is contained in:
Yann Collet 2019-08-06 14:46:31 +02:00
parent ce9176a68d
commit e18fbd51c1
2 changed files with 66 additions and 64 deletions

129
lib/lz4.c
View File

@ -183,6 +183,60 @@
#define MEM_INIT(p,v,s) memset((p),(v),(s))
/*-************************************
* Common Constants
**************************************/
#define MINMATCH 4
#define WILDCOPYLENGTH 8
#define LASTLITERALS 5 /* see ../doc/lz4_Block_format.md#parsing-restrictions */
#define MFLIMIT 12 /* see ../doc/lz4_Block_format.md#parsing-restrictions */
#define MATCH_SAFEGUARD_DISTANCE ((2*WILDCOPYLENGTH) - MINMATCH) /* ensure it's possible to write 2 x wildcopyLength without overflowing output buffer */
#define FASTLOOP_SAFE_DISTANCE 64
static const int LZ4_minLength = (MFLIMIT+1);
#define KB *(1 <<10)
#define MB *(1 <<20)
#define GB *(1U<<30)
#define LZ4_DISTANCE_ABSOLUTE_MAX 65535
#if (LZ4_DISTANCE_MAX > LZ4_DISTANCE_ABSOLUTE_MAX) /* max supported by LZ4 format */
# error "LZ4_DISTANCE_MAX is too big : must be <= 65535"
#endif
#define ML_BITS 4
#define ML_MASK ((1U<<ML_BITS)-1)
#define RUN_BITS (8-ML_BITS)
#define RUN_MASK ((1U<<RUN_BITS)-1)
/*-************************************
* Error detection
**************************************/
#if defined(LZ4_DEBUG) && (LZ4_DEBUG>=1)
# include <assert.h>
#else
# ifndef assert
# define assert(condition) ((void)0)
# endif
#endif
#define LZ4_STATIC_ASSERT(c) { enum { LZ4_static_assert = 1/(int)(!!(c)) }; } /* use after variable declarations */
#if defined(LZ4_DEBUG) && (LZ4_DEBUG>=2)
# include <stdio.h>
static int g_debuglog_enable = 1;
# define DEBUGLOG(l, ...) { \
if ((g_debuglog_enable) && (l<=LZ4_DEBUG)) { \
fprintf(stderr, __FILE__ ": "); \
fprintf(stderr, __VA_ARGS__); \
fprintf(stderr, " \n"); \
} }
#else
# define DEBUGLOG(l, ...) {} /* disabled */
#endif
/*-************************************
* Types
**************************************/
@ -364,29 +418,35 @@ LZ4_wildCopy32(void* dstPtr, const void* srcPtr, void* dstEnd)
do { memcpy(d,s,16); memcpy(d+16,s+16,16); d+=32; s+=32; } while (d<e);
}
/* LZ4_memcpy_using_offset() presumes :
* - dstEnd >= dstPtr + MINMATCH
* - there is at least 8 bytes available to write after dstEnd */
LZ4_FORCE_O2_INLINE_GCC_PPC64LE void
LZ4_memcpy_using_offset(BYTE* dstPtr, const BYTE* srcPtr, BYTE* dstEnd, const size_t offset)
{
BYTE v[8];
assert(dstEnd >= dstPtr + MINMATCH);
LZ4_write32(dstPtr, 0); /* silence an msan warning when offset==0 */
switch(offset) {
case 1:
memset(v, *srcPtr, 8);
goto copy_loop;
break;
case 2:
memcpy(v, srcPtr, 2);
memcpy(&v[2], srcPtr, 2);
memcpy(&v[4], &v[0], 4);
goto copy_loop;
break;
case 4:
memcpy(v, srcPtr, 4);
memcpy(&v[4], srcPtr, 4);
goto copy_loop;
break;
default:
LZ4_memcpy_using_offset_base(dstPtr, srcPtr, dstEnd, offset);
return;
}
copy_loop:
memcpy(dstPtr, v, 8);
dstPtr += 8;
while (dstPtr < dstEnd) {
@ -397,60 +457,6 @@ LZ4_memcpy_using_offset(BYTE* dstPtr, const BYTE* srcPtr, BYTE* dstEnd, const si
#endif
/*-************************************
* Common Constants
**************************************/
#define MINMATCH 4
#define WILDCOPYLENGTH 8
#define LASTLITERALS 5 /* see ../doc/lz4_Block_format.md#parsing-restrictions */
#define MFLIMIT 12 /* see ../doc/lz4_Block_format.md#parsing-restrictions */
#define MATCH_SAFEGUARD_DISTANCE ((2*WILDCOPYLENGTH) - MINMATCH) /* ensure it's possible to write 2 x wildcopyLength without overflowing output buffer */
#define FASTLOOP_SAFE_DISTANCE 64
static const int LZ4_minLength = (MFLIMIT+1);
#define KB *(1 <<10)
#define MB *(1 <<20)
#define GB *(1U<<30)
#define LZ4_DISTANCE_ABSOLUTE_MAX 65535
#if (LZ4_DISTANCE_MAX > LZ4_DISTANCE_ABSOLUTE_MAX) /* max supported by LZ4 format */
# error "LZ4_DISTANCE_MAX is too big : must be <= 65535"
#endif
#define ML_BITS 4
#define ML_MASK ((1U<<ML_BITS)-1)
#define RUN_BITS (8-ML_BITS)
#define RUN_MASK ((1U<<RUN_BITS)-1)
/*-************************************
* Error detection
**************************************/
#if defined(LZ4_DEBUG) && (LZ4_DEBUG>=1)
# include <assert.h>
#else
# ifndef assert
# define assert(condition) ((void)0)
# endif
#endif
#define LZ4_STATIC_ASSERT(c) { enum { LZ4_static_assert = 1/(int)(!!(c)) }; } /* use after variable declarations */
#if defined(LZ4_DEBUG) && (LZ4_DEBUG>=2)
# include <stdio.h>
static int g_debuglog_enable = 1;
# define DEBUGLOG(l, ...) { \
if ((g_debuglog_enable) && (l<=LZ4_DEBUG)) { \
fprintf(stderr, __FILE__ ": "); \
fprintf(stderr, __VA_ARGS__); \
fprintf(stderr, " \n"); \
} }
#else
# define DEBUGLOG(l, ...) {} /* disabled */
#endif
/*-************************************
* Common functions
**************************************/
@ -1946,12 +1952,6 @@ LZ4_decompress_generic(
length = token & ML_MASK;
_copy_match:
if (!partialDecoding) {
assert(oend > op);
assert(oend - op >= 4);
LZ4_write32(op, 0); /* silence an msan warning when offset==0; costs <1%; */
} /* note : when partialDecoding, there is no guarantee that at least 4 bytes remain available in output buffer */
if (length == ML_MASK) {
variable_length_error error = ok;
length += read_variable_length(&ip, iend - LASTLITERALS + 1, endOnInput, 0, &error);
@ -2013,6 +2013,7 @@ LZ4_decompress_generic(
}
if (unlikely(offset<8)) {
LZ4_write32(op, 0); /* silence msan warning when offset==0 */
op[0] = match[0];
op[1] = match[1];
op[2] = match[2];

1
tests/.gitignore vendored
View File

@ -15,6 +15,7 @@ checkFrame
# test artefacts
tmp*
versionsTest
lz4_all.c
# local tests
afl