[fuzzer] Add dictionary fuzzers

tests/fuzz/dictionary_round_trip.c

@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ */
+
+/**
+ * This fuzz target performs a zstd round-trip test (compress & decompress) with
+ * a dictionary, compares the result with the original, and calls abort() on
+ * corruption.
+ */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "fuzz_helpers.h"
+#include "zstd_helpers.h"
+
+static const int kMaxClevel = 19;
+
+static ZSTD_CCtx *cctx = NULL;
+static ZSTD_DCtx *dctx = NULL;
+static void* cBuf = NULL;
+static void* rBuf = NULL;
+static size_t bufSize = 0;
+static uint32_t seed;
+
+static size_t roundTripTest(void *result, size_t resultCapacity,
+                            void *compressed, size_t compressedCapacity,
+                            const void *src, size_t srcSize)
+{
+    FUZZ_dict_t dict = FUZZ_train(src, srcSize, &seed);
+    size_t cSize;
+    if ((FUZZ_rand(&seed) & 15) == 0) {
+        int const cLevel = FUZZ_rand(&seed) % kMaxClevel;
+
+        cSize = ZSTD_compress_usingDict(cctx,
+                compressed, compressedCapacity,
+                src, srcSize,
+                dict.buff, dict.size,
+                cLevel);
+    } else {
+        FUZZ_setRandomParameters(cctx, srcSize, &seed);
+        FUZZ_ZASSERT(ZSTD_CCtx_loadDictionary(cctx, dict.buff, dict.size));
+        cSize = ZSTD_compress2(cctx, compressed, compressedCapacity, src, srcSize);
+    }
+    FUZZ_ZASSERT(cSize);
+    {
+        size_t const ret = ZSTD_decompress_usingDict(dctx,
+                result, resultCapacity,
+                compressed, cSize,
+                dict.buff, dict.size);
+        free(dict.buff);
+        return ret;
+    }
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
+{
+    size_t neededBufSize;
+
+    seed = FUZZ_seed(&src, &size);
+    neededBufSize = ZSTD_compressBound(size);
+
+    /* Allocate all buffers and contexts if not already allocated */
+    if (neededBufSize > bufSize) {
+        free(cBuf);
+        free(rBuf);
+        cBuf = malloc(neededBufSize);
+        rBuf = malloc(neededBufSize);
+        bufSize = neededBufSize;
+        FUZZ_ASSERT(cBuf && rBuf);
+    }
+    if (!cctx) {
+        cctx = ZSTD_createCCtx();
+        FUZZ_ASSERT(cctx);
+    }
+    if (!dctx) {
+        dctx = ZSTD_createDCtx();
+        FUZZ_ASSERT(dctx);
+    }
+
+    {
+        size_t const result =
+            roundTripTest(rBuf, neededBufSize, cBuf, neededBufSize, src, size);
+        FUZZ_ZASSERT(result);
+        FUZZ_ASSERT_MSG(result == size, "Incorrect regenerated size");
+        FUZZ_ASSERT_MSG(!memcmp(src, rBuf, size), "Corruption!");
+    }
+#ifndef STATEFUL_FUZZING
+    ZSTD_freeCCtx(cctx); cctx = NULL;
+    ZSTD_freeDCtx(dctx); dctx = NULL;
+#endif
+    return 0;
+}