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build: fuzzer that targets node::LoadEnvironment()
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Refs: #34761
Refs: #33724

PR-URL: #34844
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>
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DavidKorczynski authored and MylesBorins committed Nov 16, 2020
1 parent 42c4795 commit f3a0457
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43 changes: 43 additions & 0 deletions node.gyp
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Expand Up @@ -1143,6 +1143,49 @@
}],
],
}, # fuzz_url
{ # fuzz_env
'target_name': 'fuzz_env',
'type': 'executable',
'dependencies': [
'<(node_lib_target_name)',
'deps/histogram/histogram.gyp:histogram',
'deps/uvwasi/uvwasi.gyp:uvwasi',
'node_dtrace_header',
'node_dtrace_ustack',
'node_dtrace_provider',
],
'includes': [
'node.gypi'
],
'include_dirs': [
'src',
'tools/msvs/genfiles',
'deps/v8/include',
'deps/cares/include',
'deps/uv/include',
'deps/uvwasi/include',
'test/cctest',
],
'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_env.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_env
{
'target_name': 'cctest',
'type': 'executable',
Expand Down
107 changes: 107 additions & 0 deletions test/fuzzers/fuzz_env.cc
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/*
* A fuzzer focused on the node::LoadEnvironment() function.
*
* Code here has been inspired by the cctest test case.
*/

#include <stdlib.h>
#include "node.h"
#include "node_platform.h"
#include "node_internals.h"
#include "env-inl.h"
#include "util-inl.h"
#include "v8.h"
#include "libplatform/libplatform.h"
#include "aliased_buffer.h"
#include "fuzz_helper.h"

using node::AliasedBufferBase;

/* General set up */
using ArrayBufferUniquePtr = std::unique_ptr<node::ArrayBufferAllocator,
decltype(&node::FreeArrayBufferAllocator)>;
using TracingAgentUniquePtr = std::unique_ptr<node::tracing::Agent>;
using NodePlatformUniquePtr = std::unique_ptr<node::NodePlatform>;

static TracingAgentUniquePtr tracing_agent;
static NodePlatformUniquePtr platform;
static uv_loop_t current_loop;

extern "C" int LLVMFuzzerInitialize(int* argc, char*** argv) {
uv_os_unsetenv("NODE_OPTIONS");
std::vector<std::string> node_argv{ "fuzz_env" };
std::vector<std::string> exec_argv;
std::vector<std::string> errors;

node::InitializeNodeWithArgs(&node_argv, &exec_argv, &errors);

tracing_agent = std::make_unique<node::tracing::Agent>();
node::tracing::TraceEventHelper::SetAgent(tracing_agent.get());
node::tracing::TracingController* tracing_controller =
tracing_agent->GetTracingController();
CHECK_EQ(0, uv_loop_init(&current_loop));
static constexpr int kV8ThreadPoolSize = 4;
platform.reset(
new node::NodePlatform(kV8ThreadPoolSize, tracing_controller));
v8::V8::InitializePlatform(platform.get());
v8::V8::Initialize();
return 0;
}

class FuzzerFixtureHelper {
public:
v8::Isolate* isolate_;
ArrayBufferUniquePtr allocator;

FuzzerFixtureHelper()
: allocator(ArrayBufferUniquePtr(node::CreateArrayBufferAllocator(),
&node::FreeArrayBufferAllocator)) {
isolate_ = NewIsolate(allocator.get(), &current_loop, platform.get());
CHECK_NOT_NULL(isolate_);
isolate_->Enter();
};

void Teardown() {
platform->DrainTasks(isolate_);
isolate_->Exit();
platform->UnregisterIsolate(isolate_);
isolate_->Dispose();
isolate_ = nullptr;
}
};

void EnvTest(v8::Isolate* isolate_, char* env_string) {
const v8::HandleScope handle_scope(isolate_);
Argv argv;

node::EnvironmentFlags::Flags flags = node::EnvironmentFlags::kDefaultFlags;
auto isolate = handle_scope.GetIsolate();
v8::Local<v8::Context> context_ = node::NewContext(isolate);
context_->Enter();

node::IsolateData* isolate_data_ = node::CreateIsolateData(isolate, &current_loop,
platform.get());
std::vector<std::string> args(*argv, *argv + 1);
std::vector<std::string> exec_args(*argv, *argv + 1);
node::Environment* environment_ = node::CreateEnvironment(isolate_data_,
context_, args, exec_args, flags);
node::Environment* envi = environment_;
SetProcessExitHandler(envi, [&](node::Environment* env_, int exit_code) {
node::Stop(envi);
});
node::LoadEnvironment(envi, env_string);

// Cleanup!
node::FreeEnvironment(environment_);
node::FreeIsolateData(isolate_data_);
context_->Exit();
}

extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data2, size_t size) {
FuzzerFixtureHelper ffh;
std::string s(reinterpret_cast<const char*>(data2), size);
EnvTest(ffh.isolate_, (char*)s.c_str());
ffh.Teardown();
return 0;
}

42 changes: 42 additions & 0 deletions test/fuzzers/fuzz_helper.h
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struct Argv {
public:
Argv() : Argv({"node", "-p", "process.version"}) {}

Argv(const std::initializer_list<const char*> &args) {
nr_args_ = args.size();
int total_len = 0;
for (auto it = args.begin(); it != args.end(); ++it) {
total_len += strlen(*it) + 1;
}
argv_ = static_cast<char**>(malloc(nr_args_ * sizeof(char*)));
argv_[0] = static_cast<char*>(malloc(total_len));
int i = 0;
int offset = 0;
for (auto it = args.begin(); it != args.end(); ++it, ++i) {
int len = strlen(*it) + 1;
snprintf(argv_[0] + offset, len, "%s", *it);
// Skip argv_[0] as it points the correct location already
if (i > 0) {
argv_[i] = argv_[0] + offset;
}
offset += len;
}
}

~Argv() {
free(argv_[0]);
free(argv_);
}

int nr_args() const {
return nr_args_;
}

char** operator*() const {
return argv_;
}

private:
char** argv_;
int nr_args_;
};

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