From 20eb0958822af10440cfd689925e689fd041caeb Mon Sep 17 00:00:00 2001
From: senhuang42 <senhuang96@fb.com>
Date: Sat, 22 Aug 2020 13:26:33 -0400
Subject: [PATCH] Added unit test to fuzzer.c, changed definition param name

---
 lib/decompress/zstd_decompress.c | 20 ++++++++++---------
 lib/zstd.h                       |  2 +-
 tests/fuzzer.c                   | 34 ++++++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+), 10 deletions(-)

diff --git a/lib/decompress/zstd_decompress.c b/lib/decompress/zstd_decompress.c
index 0177f1d4..21e724d7 100644
--- a/lib/decompress/zstd_decompress.c
+++ b/lib/decompress/zstd_decompress.c
@@ -676,12 +676,14 @@ static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx,
         RETURN_ERROR_IF((U64)(op-ostart) != dctx->fParams.frameContentSize,
                         corruption_detected, "");
     }
-    if (dctx->fParams.checksumFlag && !dctx->forceIgnoreChecksum) { /* Frame content checksum verification */
-        U32 const checkCalc = (U32)XXH64_digest(&dctx->xxhState);
-        U32 checkRead;
-        RETURN_ERROR_IF(remainingSrcSize<4, checksum_wrong, "");
-        checkRead = MEM_readLE32(ip);
-        RETURN_ERROR_IF(checkRead != checkCalc, checksum_wrong, "");
+    if (dctx->fParams.checksumFlag) { /* Frame content checksum verification */
+        if (!dctx->forceIgnoreChecksum) {
+            U32 const checkCalc = (U32)XXH64_digest(&dctx->xxhState);
+            U32 checkRead;
+            RETURN_ERROR_IF(remainingSrcSize<4, checksum_wrong, "");
+            checkRead = MEM_readLE32(ip);
+            RETURN_ERROR_IF(checkRead != checkCalc, checksum_wrong, "");
+        }
         ip += 4;
         remainingSrcSize -= 4;
     }
@@ -978,7 +980,7 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, c
             RETURN_ERROR_IF(rSize > dctx->fParams.blockSizeMax, corruption_detected, "Decompressed Block Size Exceeds Maximum");
             DEBUGLOG(5, "ZSTD_decompressContinue: decoded size from block : %u", (unsigned)rSize);
             dctx->decodedSize += rSize;
-            if (dctx->fParams.checksumFlag) XXH64_update(&dctx->xxhState, dst, rSize);
+            if (dctx->fParams.checksumFlag && !dctx->forceIgnoreChecksum) XXH64_update(&dctx->xxhState, dst, rSize);
             dctx->previousDstEnd = (char*)dst + rSize;
 
             /* Stay on the same stage until we are finished streaming the block. */
@@ -1398,9 +1400,9 @@ size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format)
     return ZSTD_DCtx_setParameter(dctx, ZSTD_d_format, format);
 }
 
-size_t ZSTD_DCtx_setForceIgnoreChecksum(ZSTD_DCtx* dctx, ZSTD_forceIgnoreChecksum_e shouldIgnore)
+size_t ZSTD_DCtx_setForceIgnoreChecksum(ZSTD_DCtx* dctx, ZSTD_forceIgnoreChecksum_e value)
 {
-    return ZSTD_DCtx_setParameter(dctx, ZSTD_d_forceIgnoreChecksum, shouldIgnore);
+    return ZSTD_DCtx_setParameter(dctx, ZSTD_d_forceIgnoreChecksum, value);
 }
 
 ZSTD_bounds ZSTD_dParam_getBounds(ZSTD_dParameter dParam)
diff --git a/lib/zstd.h b/lib/zstd.h
index c5dd2e94..9f9f991f 100644
--- a/lib/zstd.h
+++ b/lib/zstd.h
@@ -1717,7 +1717,7 @@ ZSTDLIB_API size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format);
 /*! ZSTD_DCtx_setForceIgnoreChecksum() :
  *  Instruct the decoder context to ignore checksums in compressed frame.
  * @return : 0, or an error code (which can be tested using ZSTD_isError()). */
-ZSTDLIB_API size_t ZSTD_DCtx_setForceIgnoreChecksum(ZSTD_DCtx* dctx, ZSTD_forceIgnoreChecksum_e format);
+ZSTDLIB_API size_t ZSTD_DCtx_setForceIgnoreChecksum(ZSTD_DCtx* dctx, ZSTD_forceIgnoreChecksum_e value);
 
 /*! ZSTD_decompressStream_simpleArgs() :
  *  Same as ZSTD_decompressStream(),
diff --git a/tests/fuzzer.c b/tests/fuzzer.c
index 8ac2864f..4f0676ab 100644
--- a/tests/fuzzer.c
+++ b/tests/fuzzer.c
@@ -544,6 +544,40 @@ static int basicUnitTests(U32 const seed, double compressibility)
       if (ZSTD_getErrorCode(r) != ZSTD_error_dstSize_tooSmall) goto _output_error; }
     DISPLAYLEVEL(3, "OK \n");
 
+    DISPLAYLEVEL(3, "test%3i : decompress with corrupted checksum : ", testNb++);
+    {   /* create compressed buffer with checksumming enabled */
+        ZSTD_CCtx* const cctx = ZSTD_createCCtx();
+        CHECK_Z( ZSTD_CCtx_setParameter(cctx, ZSTD_c_checksumFlag, 1) );
+        CHECK_VAR(cSize, ZSTD_compress2(cctx,
+                            compressedBuffer, compressedBufferSize,
+                            CNBuffer, CNBuffSize) );
+        ZSTD_freeCCtx(cctx);
+    }
+    {   /* copy the compressed buffer and corrupt the checksum */
+        char* corruptedChecksumCompressedBuffer = (char*)malloc(cSize);
+        if (!corruptedChecksumCompressedBuffer) {
+            DISPLAY("Not enough memory, aborting\n");
+            testResult = 1;
+            goto _end;
+        }
+
+        memcpy(corruptedChecksumCompressedBuffer, compressedBuffer, cSize);
+        corruptedChecksumCompressedBuffer[cSize-1] += 1;
+        size_t r = ZSTD_decompress(decodedBuffer, CNBuffSize, corruptedChecksumCompressedBuffer, cSize);
+        if (!ZSTD_isError(r)) goto _output_error;
+        if (ZSTD_getErrorCode(r) != ZSTD_error_checksum_wrong) goto _output_error;
+
+        ZSTD_DCtx* dctx = ZSTD_createDCtx(); assert(dctx != NULL);
+        CHECK_Z(ZSTD_DCtx_setForceIgnoreChecksum(dctx, ZSTD_d_ignoreChecksum));
+        r = ZSTD_decompressDCtx(dctx, decodedBuffer, CNBuffSize, corruptedChecksumCompressedBuffer, cSize);
+        if (ZSTD_isError(r)) goto _output_error;
+
+        ZSTD_freeDCtx(dctx);
+        free(corruptedChecksumCompressedBuffer);
+    }
+    DISPLAYLEVEL(3, "OK \n");
+
+
     DISPLAYLEVEL(3, "test%3i : ZSTD_decompressBound test with content size missing : ", testNb++);
     {   /* create compressed buffer with content size missing */
         ZSTD_CCtx* const cctx = ZSTD_createCCtx();