Merge pull request #918 from lz4/usan_null

Properly fix #847

2 files changed, 54 insertions, 6 deletions

diff --git a/lib/lz4.c b/lib/lz4.c
index 0628eac..2222d53 100644
--- a/lib/lz4.c
+++ b/lib/lz4.c
@@ -819,8 +819,12 @@ LZ4_prepareTable(LZ4_stream_t_internal* const cctx,
 }
 
 /** LZ4_compress_generic() :
-    inlined, to ensure branches are decided at compilation time */
-LZ4_FORCE_INLINE int LZ4_compress_generic(
+ *  inlined, to ensure branches are decided at compilation time.
+ *  Presumed already validated at this stage:
+ *  - source != NULL
+ *  - inputSize > 0
+ */
+LZ4_FORCE_INLINE int LZ4_compress_generic_validated(
                  LZ4_stream_t_internal* const cctx,
                  const char* const source,
                  char* const dest,
@@ -867,11 +871,11 @@ LZ4_FORCE_INLINE int LZ4_compress_generic(
     U32 offset = 0;
     U32 forwardH;
 
-    DEBUGLOG(5, "LZ4_compress_generic: srcSize=%i, tableType=%u", inputSize, tableType);
+    DEBUGLOG(5, "LZ4_compress_generic_validated: srcSize=%i, tableType=%u", inputSize, tableType);
+    assert(ip != NULL);
     /* If init conditions are not met, we don't have to mark stream
      * as having dirty context, since no action was taken yet */
     if (outputDirective == fillOutput && maxOutputSize < 1) { return 0; } /* Impossible to store anything */
-    if ((U32)inputSize > (U32)LZ4_MAX_INPUT_SIZE) { return 0; }           /* Unsupported inputSize, too large (or negative) */
     if ((tableType == byU16) && (inputSize>=LZ4_64Klimit)) { return 0; }  /* Size too large (not within 64K limit) */
     if (tableType==byPtr) assert(dictDirective==noDict);      /* only supported use case with byPtr */
     assert(acceleration >= 1);
@@ -1204,12 +1208,52 @@ _last_literals:
     if (outputDirective == fillOutput) {
         *inputConsumed = (int) (((const char*)ip)-source);
     }
-    DEBUGLOG(5, "LZ4_compress_generic: compressed %i bytes into %i bytes", inputSize, (int)(((char*)op) - dest));
     result = (int)(((char*)op) - dest);
     assert(result > 0);
+    DEBUGLOG(5, "LZ4_compress_generic: compressed %i bytes into %i bytes", inputSize, result);
     return result;
 }
 
+/** LZ4_compress_generic() :
+ *  inlined, to ensure branches are decided at compilation time;
+ *  takes care of src == (NULL, 0)
+ *  and forward the rest to LZ4_compress_generic_validated */
+LZ4_FORCE_INLINE int LZ4_compress_generic(
+                 LZ4_stream_t_internal* const cctx,
+                 const char* const src,
+                 char* const dst,
+                 const int srcSize,
+                 int *inputConsumed, /* only written when outputDirective == fillOutput */
+                 const int dstCapacity,
+                 const limitedOutput_directive outputDirective,
+                 const tableType_t tableType,
+                 const dict_directive dictDirective,
+                 const dictIssue_directive dictIssue,
+                 const int acceleration)
+{
+    DEBUGLOG(5, "LZ4_compress_generic: srcSize=%i, dstCapacity=%i",
+                srcSize, dstCapacity);
+
+    if ((U32)srcSize > (U32)LZ4_MAX_INPUT_SIZE) { return 0; }  /* Unsupported srcSize, too large (or negative) */
+    if (srcSize == 0) {   /* src == NULL supported if srcSize == 0 */
+        DEBUGLOG(5, "Generating an empty block");
+        assert(outputDirective == notLimited || dstCapacity >= 1);
+        assert(dst != NULL);
+        dst[0] = 0;
+        if (outputDirective == fillOutput) {
+            assert (inputConsumed != NULL);
+            *inputConsumed = 0;
+        }
+        return 1;
+    }
+    assert(src != NULL);
+
+    return LZ4_compress_generic_validated(cctx, src, dst, srcSize,
+                inputConsumed, /* only written into if outputDirective == fillOutput */
+                dstCapacity, outputDirective,
+                tableType, dictDirective, dictIssue, acceleration);
+}
+
 
 int LZ4_compress_fast_extState(void* state, const char* source, char* dest, int inputSize, int maxOutputSize, int acceleration)
 {
@@ -2077,6 +2121,7 @@ LZ4_decompress_generic(
 
         /* end of decoding */
         if (endOnInput) {
+            DEBUGLOG(5, "decoded %i bytes", (int) (((char*)op)-dst));
            return (int) (((char*)op)-dst);     /* Nb of output bytes decoded */
        } else {
            return (int) (((const char*)ip)-src);   /* Nb of input bytes read */
diff --git a/lib/lz4frame.c b/lib/lz4frame.c
index e11f1c8..890fc96 100644
--- a/lib/lz4frame.c
+++ b/lib/lz4frame.c
@@ -750,6 +750,7 @@ static size_t LZ4F_makeBlock(void* dst,
                                       (int)(srcSize), (int)(srcSize-1),
                                       level, cdict);
     if (cSize == 0) {  /* compression failed */
+        DEBUGLOG(5, "LZ4F_makeBlock: compression failed, creating a raw block (size %u)", (U32)srcSize);
         cSize = (U32)srcSize;
         LZ4F_writeLE32(cSizePtr, cSize | LZ4F_BLOCKUNCOMPRESSED_FLAG);
         memcpy(cSizePtr+BHSize, src, srcSize);
@@ -1487,15 +1488,17 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx,
                 size_t const nextCBlockSize = blockHeader & 0x7FFFFFFFU;
                 size_t const crcSize = dctx->frameInfo.blockChecksumFlag * BFSize;
                 if (blockHeader==0) {  /* frameEnd signal, no more block */
+                    DEBUGLOG(5, "end of frame");
                     dctx->dStage = dstage_getSuffix;
                     break;
                 }
                 if (nextCBlockSize > dctx->maxBlockSize) {
                     return err0r(LZ4F_ERROR_maxBlockSize_invalid);
                 }
-                if (LZ4F_readLE32(selectedIn) & LZ4F_BLOCKUNCOMPRESSED_FLAG) {
+                if (blockHeader & LZ4F_BLOCKUNCOMPRESSED_FLAG) {
                     /* next block is uncompressed */
                     dctx->tmpInTarget = nextCBlockSize;
+                    DEBUGLOG(5, "next block is uncompressed (size %u)", (U32)nextCBlockSize);
                     if (dctx->frameInfo.blockChecksumFlag) {
                         (void)XXH32_reset(&dctx->blockChecksum, 0);
                     }