1 files changed, 58 insertions, 0 deletions
diff --git a/ossfuzz/decompress_fuzzer.c b/ossfuzz/decompress_fuzzer.c
new file mode 100644
index 0000000..0267c93
--- /dev/null
+++ b/ossfuzz/decompress_fuzzer.c
@@ -0,0 +1,58 @@
+/**
+ * This fuzz target attempts to decompress the fuzzed data with the simple
+ * decompression function to ensure the decompressor never crashes.
+ */
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "fuzz_helpers.h"
+#include "lz4.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+
+    uint32_t seed = FUZZ_seed(&data, &size);
+    size_t const dstCapacity = FUZZ_rand32(&seed, 0, 4 * size);
+    size_t const smallDictSize = size + 1;
+    size_t const largeDictSize = 64 * 1024 - 1;
+    size_t const dictSize = MAX(smallDictSize, largeDictSize);
+    char* const dst = (char*)malloc(dstCapacity);
+    char* const dict = (char*)malloc(dictSize + size);
+    char* const largeDict = dict;
+    char* const dataAfterDict = dict + dictSize;
+    char* const smallDict = dataAfterDict - smallDictSize;
+
+    FUZZ_ASSERT(dst);
+    FUZZ_ASSERT(dict);
+
+    /* Prepare the dictionary. The data doesn't matter for decompression. */
+    memset(dict, 0, dictSize);
+    memcpy(dataAfterDict, data, size);
+
+    /* Decompress using each possible dictionary configuration. */
+    /* No dictionary. */
+    LZ4_decompress_safe_usingDict((char const*)data, dst, size,
+                                  dstCapacity, NULL, 0);
+    /* Small external dictonary. */
+    LZ4_decompress_safe_usingDict((char const*)data, dst, size,
+                                  dstCapacity, smallDict, smallDictSize);
+    /* Large external dictionary. */
+    LZ4_decompress_safe_usingDict((char const*)data, dst, size,
+                                  dstCapacity, largeDict, largeDictSize);
+    /* Small prefix. */
+    LZ4_decompress_safe_usingDict((char const*)dataAfterDict, dst, size,
+                                  dstCapacity, smallDict, smallDictSize);
+    /* Large prefix. */
+    LZ4_decompress_safe_usingDict((char const*)data, dst, size,
+                                  dstCapacity, largeDict, largeDictSize);
+    /* Partial decompression. */
+    LZ4_decompress_safe_partial((char const*)data, dst, size,
+                                dstCapacity, dstCapacity);
+    free(dst);
+    free(dict);
+
+    return 0;
+}