build: add build flag for OSS-Fuzz integration

Refs: google/oss-fuzz#3860
Fixes: #33724

PR-URL: #34761
Fixes: #33724
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Rich Trott <rtrott@gmail.com>

configure.py

@@ -439,6 +439,11 @@
     dest='v8_options',
     help='v8 options to pass, see `node --v8-options` for examples.')
 
+parser.add_option('--with-ossfuzz',
+    action='store_true',
+    dest='ossfuzz',
+    help='Enables building of fuzzers. This command should be run in an OSS-Fuzz Docker image.')
+
 parser.add_option('--with-arm-float-abi',
     action='store',
     dest='arm_float_abi',
@@ -1827,6 +1832,9 @@ def make_bin_override():
 configure_static(output)
 configure_inspector(output)
 
+# Forward OSS-Fuzz settings
+output['variables']['ossfuzz'] = b(options.ossfuzz)
+
 # variables should be a root level element,
 # move everything else to target_defaults
 variables = output['variables']

node.gyp

@@ -13,6 +13,7 @@
     'node_use_bundled_v8%': 'true',
     'node_shared%': 'false',
     'force_dynamic_crt%': 0,
+    'ossfuzz' : 'false',
     'node_module_version%': '',
     'node_shared_brotli%': 'false',
     'node_shared_zlib%': 'false',
@@ -1170,6 +1171,38 @@
         } ],
       ]
     }, # specialize_node_d
+    { # fuzz_url
+      'target_name': 'fuzz_url',
+      'type': 'executable',
+      'dependencies': [
+        '<(node_lib_target_name)',
+      ],
+      'includes': [
+        'node.gypi'
+      ],
+      'include_dirs': [
+        'src',
+      ],
+      'defines': [
+        'NODE_ARCH="<(target_arch)"',
+        'NODE_PLATFORM="<(OS)"',
+        'NODE_WANT_INTERNALS=1',
+      ],
+      'sources': [
+        'src/node_snapshot_stub.cc',
+        'src/node_code_cache_stub.cc',
+        'test/fuzzers/fuzz_url.cc',
+      ],
+      'conditions': [
+        ['OS=="linux"', {
+          'ldflags': [ '-fsanitize=fuzzer' ]
+        }],
+        # Ensure that ossfuzz flag has been set and that we are on Linux
+        [ 'OS!="linux" or ossfuzz!="true"', {
+          'type': 'none',
+        }],
+      ],
+    }, # fuzz_url
     {
       'target_name': 'cctest',
       'type': 'executable',

test/fuzzers/fuzz_url.cc

@@ -0,0 +1,11 @@
+#include <stdlib.h>
+
+#include "node.h"
+#include "node_internals.h"
+#include "node_url.h"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+    node::url::URL url2(reinterpret_cast<const char*>(data), size);
+
+    return 0;
+}