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/*
* Copyright (c) 2020, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Function.h>
#include <AK/String.h>
#include <AK/StringView.h>
#include <LibJS/Forward.h>
#include <LibJS/Interpreter.h>
#include <LibJS/Lexer.h>
#include <LibJS/Parser.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
//
// BEGIN FUZZING CODE
//
#define REPRL_CRFD 100
#define REPRL_CWFD 101
#define REPRL_DRFD 102
#define REPRL_DWFD 103
#define REPRL_MAX_DATA_SIZE (16 * 1024 * 1024)
#define SHM_SIZE 0x100000
#define MAX_EDGES ((SHM_SIZE - 4) * 8)
#define CHECK(cond) \
if (!(cond)) { \
fprintf(stderr, "\"" #cond "\" failed\n"); \
_exit(-1); \
}
struct shmem_data {
uint32_t num_edges;
unsigned char edges[];
};
struct shmem_data* __shmem;
uint32_t *__edges_start, *__edges_stop;
void __sanitizer_cov_reset_edgeguards()
{
uint64_t N = 0;
for (uint32_t* x = __edges_start; x < __edges_stop && N < MAX_EDGES; x++)
*x = ++N;
}
extern "C" void __sanitizer_cov_trace_pc_guard_init(uint32_t* start, uint32_t* stop)
{
// Avoid duplicate initialization
if (start == stop || *start)
return;
if (__edges_start != NULL || __edges_stop != NULL) {
fprintf(stderr, "Coverage instrumentation is only supported for a single module\n");
_exit(-1);
}
__edges_start = start;
__edges_stop = stop;
// Map the shared memory region
const char* shm_key = getenv("SHM_ID");
if (!shm_key) {
puts("[COV] no shared memory bitmap available, skipping");
__shmem = (struct shmem_data*)malloc(SHM_SIZE);
} else {
int fd = shm_open(shm_key, O_RDWR, S_IREAD | S_IWRITE);
if (fd <= -1) {
fprintf(stderr, "Failed to open shared memory region: %s\n", strerror(errno));
_exit(-1);
}
__shmem = (struct shmem_data*)mmap(0, SHM_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (__shmem == MAP_FAILED) {
fprintf(stderr, "Failed to mmap shared memory region\n");
_exit(-1);
}
}
__sanitizer_cov_reset_edgeguards();
__shmem->num_edges = stop - start;
printf("[COV] edge counters initialized. Shared memory: %s with %u edges\n", shm_key, __shmem->num_edges);
}
extern "C" void __sanitizer_cov_trace_pc_guard(uint32_t* guard)
{
// There's a small race condition here: if this function executes in two threads for the same
// edge at the same time, the first thread might disable the edge (by setting the guard to zero)
// before the second thread fetches the guard value (and thus the index). However, our
// instrumentation ignores the first edge (see libcoverage.c) and so the race is unproblematic.
uint32_t index = *guard;
// If this function is called before coverage instrumentation is properly initialized we want to return early.
if (!index)
return;
__shmem->edges[index / 8] |= 1 << (index % 8);
*guard = 0;
}
//
// END FUZZING CODE
//
class TestRunnerGlobalObject final : public JS::GlobalObject {
JS_OBJECT(TestRunnerGlobalObject, JS::GlobalObject);
public:
TestRunnerGlobalObject();
virtual ~TestRunnerGlobalObject() override;
virtual void initialize_global_object() override;
private:
JS_DECLARE_NATIVE_FUNCTION(fuzzilli);
};
TestRunnerGlobalObject::TestRunnerGlobalObject()
{
}
TestRunnerGlobalObject::~TestRunnerGlobalObject()
{
}
JS_DEFINE_NATIVE_FUNCTION(TestRunnerGlobalObject::fuzzilli)
{
if (!vm.argument_count())
return JS::js_undefined();
auto operation = TRY(vm.argument(0).to_string(global_object));
if (operation == "FUZZILLI_CRASH") {
auto type = TRY(vm.argument(1).to_i32(global_object));
switch (type) {
case 0:
*((int*)0x41414141) = 0x1337;
break;
default:
VERIFY_NOT_REACHED();
break;
}
} else if (operation == "FUZZILLI_PRINT") {
static FILE* fzliout = fdopen(REPRL_DWFD, "w");
if (!fzliout) {
dbgln("Fuzzer output not available");
fzliout = stdout;
}
auto string = TRY(vm.argument(1).to_string(global_object));
fprintf(fzliout, "%s\n", string.characters());
fflush(fzliout);
}
return JS::js_undefined();
}
void TestRunnerGlobalObject::initialize_global_object()
{
Base::initialize_global_object();
define_direct_property("global", this, JS::Attribute::Enumerable);
define_native_function("fuzzilli", fuzzilli, 2, JS::default_attributes);
}
int main(int, char**)
{
char* reprl_input = nullptr;
char helo[] = "HELO";
if (write(REPRL_CWFD, helo, 4) != 4 || read(REPRL_CRFD, helo, 4) != 4) {
VERIFY_NOT_REACHED();
}
VERIFY(memcmp(helo, "HELO", 4) == 0);
reprl_input = (char*)mmap(0, REPRL_MAX_DATA_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, REPRL_DRFD, 0);
VERIFY(reprl_input != MAP_FAILED);
auto vm = JS::VM::create();
auto interpreter = JS::Interpreter::create<TestRunnerGlobalObject>(*vm);
while (true) {
unsigned action;
VERIFY(read(REPRL_CRFD, &action, 4) == 4);
VERIFY(action == 'cexe');
size_t script_size;
VERIFY(read(REPRL_CRFD, &script_size, 8) == 8);
VERIFY(script_size < REPRL_MAX_DATA_SIZE);
ByteBuffer data_buffer;
data_buffer.resize(script_size);
VERIFY(data_buffer.size() >= script_size);
memcpy(data_buffer.data(), reprl_input, script_size);
int result = 0;
auto js = StringView(static_cast<const unsigned char*>(data_buffer.data()), script_size);
auto parse_result = JS::Script::parse(js, interpreter->realm());
if (parse_result.is_error()) {
result = 1;
} else {
auto completion = interpreter->run(parse_result.value());
if (completion.is_error()) {
result = 1;
}
}
fflush(stdout);
fflush(stderr);
int status = (result & 0xff) << 8;
VERIFY(write(REPRL_CWFD, &status, 4) == 4);
__sanitizer_cov_reset_edgeguards();
}
return 0;
}
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