From e18fbd51c1529db7c78616a64a97ac23aa57c2fc Mon Sep 17 00:00:00 2001 From: Yann Collet Date: Tue, 6 Aug 2019 14:46:31 +0200 Subject: [PATCH] silence msan warning when offset==0 --- lib/lz4.c | 129 ++++++++++++++++++++++++----------------------- tests/.gitignore | 1 + 2 files changed, 66 insertions(+), 64 deletions(-) diff --git a/lib/lz4.c b/lib/lz4.c index c8f49cc..0849505 100644 --- a/lib/lz4.c +++ b/lib/lz4.c @@ -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<=1) +# include +#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 +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= 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<=1) -# include -#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 -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]; diff --git a/tests/.gitignore b/tests/.gitignore index c4f9092..0d13df8 100644 --- a/tests/.gitignore +++ b/tests/.gitignore @@ -15,6 +15,7 @@ checkFrame # test artefacts tmp* versionsTest +lz4_all.c # local tests afl