libmicrohttpd2: Add more fuzzing target from mhd_str (#13857)

This PR adds the final batch of target from mhd_str for project
libmicrohttpd2.

Signed-off-by: Arthur Chan <[email protected]>

Author: arthurscchan

projects/libmicrohttpd2/fuzz_str.cpp

@@ -39,6 +39,9 @@ static void fuzz_tokens(FuzzedDataProvider& fdp) {
   size_t payload_size2 = payload2.size();
   size_t payload_size3 = payload3.size();
 
+  // Fuzz mhd_str_equal_caseless
+  mhd_str_equal_caseless(payload_str1, payload_str2);
+
   // Fuzz mhd_str_equal_caseless_n
   mhd_str_equal_caseless_n(payload_str1, payload_str2, fdp.ConsumeIntegral<size_t>());
 
@@ -142,20 +145,21 @@ static void fuzz_quoted(FuzzedDataProvider& fdp) {
   // Fuzz mhd_str_equal_quoted_bin_n with random string payload as binary
   mhd_str_equal_quoted_bin_n(payload_str1, payload_size1, payload_str2, payload_size2);
 
-  // Fuzz mhd_str_quote with random string payload
+  // Fuzz mhd_str_quote and mhd_str_unquote with random string payload
   size_t max_out = payload_size1 * 2;
   char *out = (char*) malloc(max_out);
   if (out) {
     mhd_str_quote(payload_str1, payload_size1, out, max_out);
+    mhd_str_unquote(payload_str1, payload_size1, out);
   }
   free(out);
 
   max_out = payload_size2 * 2;
   out = (char*) malloc(max_out);
   if (out) {
     mhd_str_quote(payload_str2, payload_size2, out, max_out);
+    mhd_str_unquote(payload_str2, payload_size2, out);
   }
-
   free(out);
 }
 
@@ -194,17 +198,49 @@ static void fuzz_transformation(FuzzedDataProvider& fdp) {
   }
 }
 
+static void fuzz_hex_conversion(FuzzedDataProvider& fdp) {
+  // Prepare random data for hex conversion
+  std::string payload = fdp.ConsumeRandomLengthString(1024);
+  char *payload_str = payload.data();
+  size_t payload_size = payload.size();
+
+  // Fuzz mhd_hex_to_bin with random payload
+  uint8_t *bin_out = (uint8_t*) malloc(payload_size);
+  if (bin_out) {
+    mhd_hex_to_bin(payload_str, payload_size, bin_out);
+    free(bin_out);
+  }
+
+  // Fuzz mhd_bin_to_hex with random payload
+  char *hex_out = (char *) malloc(payload_size * 2);
+  if (hex_out) {
+    if (!payload.empty()) {
+      mhd_bin_to_hex(payload_str, payload_size, hex_out);
+    }
+    free(hex_out);
+  }
+
+  char *hexz_out = (char *) malloc(payload_size * 2 + 1);
+  if (hexz_out) {
+    if (!payload.empty()) {
+      mhd_bin_to_hex(payload_str, payload_size, hexz_out);
+    }
+    free(hexz_out);
+  }
+}
+
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   FuzzedDataProvider fdp(data, size);
 
   for (int i = 0; i < fdp.ConsumeIntegralInRange<unsigned>(1, 6); i++) {
-    switch (fdp.ConsumeIntegralInRange<int>(0, 6)) {
+    switch (fdp.ConsumeIntegralInRange<int>(0, 7)) {
       case 0: fuzz_tokens(fdp); break;
       case 1: fuzz_conversion(fdp); break;
       case 2: fuzz_decode(fdp); break;
       case 3: fuzz_quoted(fdp); break;
       case 4: fuzz_base64(fdp); break;
       case 5: fuzz_transformation(fdp); break;
+      case 6: fuzz_hex_conversion(fdp); break;
     }
   }
   return 0;