Simplify PerMessageDeflate fuzzing regions

fuzzing/PerMessageDeflate.cpp

@@ -4,6 +4,7 @@
 
 #include <cstdio>
 #include <string>
+#include <bitset>
 
 /* We test the permessage deflate module */
 #include "../src/PerMessageDeflate.h"
@@ -13,9 +14,7 @@
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
 
     /* First byte determines what compressor to use */
-    if (size < 1) {
-        return 0;
-    }
+    if (size >= 1) {
 
         int compressors[] = {
             uWS::DEDICATED_COMPRESSOR_3KB,
@@ -32,6 +31,9 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         data++;
         size--;
 
+        /* Bits 0 - 256 are okay */
+        std::bitset<257> b;
+
         /* If we could specify LARGE_BUFFER_SIZE small here we could force it to inflate in chunks,
         * triggering more line coverage. Currently it is set to 16kb which is always too much */
         struct StaticData {
@@ -42,12 +44,11 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         } staticData = {compressor};
 
         /* Why is this padded? */
-    makeChunked(makePadded(data, size), size, [&staticData](const uint8_t *data, size_t size) {
+        makeChunked(makePadded(data, size), size, [&staticData, &b](const uint8_t *data, size_t size) {
             auto [inflation, valid] = staticData.inflationStream.inflate(&staticData.zlibContext, std::string_view((char *) data, size), 256);
-        if (inflation.length() > 256) {
-            /* Cause ASAN to freak out */
-            delete (int *) (void *) 1;
-        }
+
+            /* Trigger ASAN flaws if length is more than 256 */
+            b.set(inflation.length());
         });
 
         makeChunked(makePadded(data, size), size, [&staticData](const uint8_t *data, size_t size) {
@@ -55,6 +56,8 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
             staticData.deflationStream.deflate(&staticData.zlibContext, std::string_view((char *) data, size), true);
         });
 
+    }
+
     return 0;
 }