Files
ce_cdm/oemcrypto/odk/test/fuzzing/odk_fuzz_helper.h
John "Juce" Bruce f11df1e144 Source release 17.1.1
2022-11-29 12:54:04 -08:00

207 lines
8.0 KiB
C++

// Copyright 2020 Google LLC. All rights reserved. This file and proprietary
// source code may only be used and distributed under the Widevine
// License Agreement.
#ifndef WIDEVINE_ODK_TEST_FUZZING_ODK_FUZZ_HELPER_H_
#define WIDEVINE_ODK_TEST_FUZZING_ODK_FUZZ_HELPER_H_
#include <memory>
#include <string>
#include "core_message_features.h"
#include "core_message_serialize.h"
#include "fuzzing/odk_fuzz_structs.h"
#include "odk_attributes.h"
#include "odk_serialize.h"
namespace oemcrypto_core_message {
bool convert_byte_to_valid_boolean(const bool* in);
OEMCryptoResult odk_serialize_LicenseRequest(
const void* in, uint8_t* out, size_t* size,
const ODK_LicenseRequest& core_license_request,
const ODK_NonceValues* nonce_values);
OEMCryptoResult odk_serialize_RenewalRequest(
const void* in, uint8_t* out, size_t* size,
const ODK_RenewalRequest& core_renewal, ODK_NonceValues* nonce_values);
OEMCryptoResult odk_serialize_ProvisioningRequest(
const void* in, uint8_t* out, size_t* size,
const ODK_ProvisioningRequest& core_provisioning,
const ODK_NonceValues* nonce_values);
OEMCryptoResult odk_deserialize_LicenseResponse(const uint8_t* message,
size_t core_message_length,
ODK_ParseLicense_Args* a,
ODK_NonceValues* nonce_values,
ODK_ParsedLicense* parsed_lic);
OEMCryptoResult odk_deserialize_RenewalResponse(
const uint8_t* buf, size_t len, ODK_ParseRenewal_Args* a,
ODK_NonceValues* nonce_values, ODK_PreparedRenewalRequest* renewal_msg);
OEMCryptoResult odk_deserialize_ProvisioningResponse(
const uint8_t* buf, size_t len, ODK_ParseProvisioning_Args* a,
ODK_NonceValues* nonce_values, ODK_ParsedProvisioning* parsed_prov);
bool kdo_serialize_LicenseResponse(const ODK_ParseLicense_Args* args,
const ODK_ParsedLicense& parsed_lic,
std::string* oemcrypto_core_message);
bool kdo_serialize_RenewalResponse(
const ODK_ParseRenewal_Args* args,
const ODK_PreparedRenewalRequest& renewal_msg,
std::string* oemcrypto_core_message);
bool kdo_serialize_ProvisioningResponse(
const ODK_ParseProvisioning_Args* args,
const ODK_ParsedProvisioning& parsed_prov,
std::string* oemcrypto_core_message);
// Idea behind having three different functions is:
// Only ODK_ParseLicense structure had fields which needed additional
// procession. Having a single function with templated parameter T was
// failing during compile time because other two structures doesn't have
// fields that need additional processing. Hence to reduce code redundance and
// make us of common FuzzerMutateResponse across three response fuzzers,
// three independent functions were defined and renewal and provisioning
// functions would be empty as no additional processing is needed for them.
void ConvertDataToValidBools(ODK_ParsedLicense* t);
void ConvertDataToValidBools(ODK_PreparedRenewalRequest* t);
void ConvertDataToValidBools(ODK_ParsedProvisioning* t);
// Forward-declare the libFuzzer's mutator callback. Mark it weak so that
// the program links successfully even outside of --config=asan-fuzzer
// (apparently the only config in which LLVM uses our custom mutator).
extern "C" size_t LLVMFuzzerMutate(uint8_t* Data, size_t Size, size_t MaxSize)
__attribute__((weak));
template <typename A, typename T, typename F, typename G>
size_t FuzzerMutateResponse(uint8_t* data, size_t size, size_t max_size,
const F& odk_deserialize_fun,
const G& kdo_serialize_fun) {
const size_t kArgsSize = sizeof(A);
const size_t kCoreResponseSize = sizeof(T);
const size_t kTotalResponseSize = kArgsSize + kCoreResponseSize;
// Deserializing data in order to make sure it deserializes properly.
// Input byte array format: [function arguments][data to parse].
std::shared_ptr<A> _args(new A());
A* args = _args.get();
memcpy(args, data, kArgsSize);
ODK_NonceValues nonce_values = args->nonce_values;
args->nonce_values.api_major_version = ODK_MAJOR_VERSION;
const uint8_t* buf = data + kArgsSize;
T t = {};
OEMCryptoResult result =
odk_deserialize_fun(buf, size - kArgsSize, args, &nonce_values, &t);
// If data doesn't deserialize successfully, We copy random bytes into
// T and serialize using kdo function
// which will create a valid oemcrypto core message using
// nonce and request hash from function args. OEMCrypto core message acts as
// input to odk_kdo.
if (result != OEMCrypto_SUCCESS) {
if (max_size < kTotalResponseSize) {
return 0;
}
// Initialize remaining bytes needed in data to zero.
if (size < kTotalResponseSize) {
memset(data + size, 0, kTotalResponseSize - size);
}
t = {};
memcpy(&t, buf, kCoreResponseSize);
}
// Ask LLVM to run its usual mutations, hopefully giving us interesting
// inputs. We copy deserialized data into pointer data, run mutations
// and copy back the mutated data to args and t
memcpy(data + kArgsSize, &t, kCoreResponseSize);
LLVMFuzzerMutate(data, kTotalResponseSize, kTotalResponseSize);
memcpy(args, data, kArgsSize);
memcpy(&t, data + kArgsSize, kCoreResponseSize);
// Convert boolean flags in parsed message to valid bytes to
// avoid errors from msan. Only needed for parsed license.
ConvertDataToValidBools(&t);
// Serialize the data after mutation.
std::string oemcrypto_core_message;
if (!kdo_serialize_fun(args, t, &oemcrypto_core_message)) {
return 0;
}
// Copy mutated and serialized oemcrypto_core_message to data
// so that it acts as input to odk_kdo function.
memcpy(data + kArgsSize, oemcrypto_core_message.data(),
oemcrypto_core_message.size());
return kArgsSize + oemcrypto_core_message.size();
}
/**
* Template arguments:
* A: struct holding function arguments
* T: odk deserialize output/kdo serialize input structure
* F: odk deserialize function
* G: kdo serialize function
*
* raw bytes -> F deserialize -> struct T -> G serialize -> raw bytes
*/
template <typename A, typename T, typename F, typename G>
void odk_kdo(const F& odk_fun, const G& kdo_fun, const uint8_t* in,
const size_t size, const size_t args_size, uint8_t* out UNUSED) {
T t = {};
// Input byte array format: [function arguments][data to parse]
if (size < args_size) {
return;
}
const uint8_t* buf = in + args_size;
std::shared_ptr<A> _args(new A());
A* args = _args.get();
memcpy(args, in, args_size);
args->nonce_values.api_major_version = ODK_MAJOR_VERSION;
ODK_NonceValues nonce_values = args->nonce_values;
OEMCryptoResult result =
odk_fun(buf, size - args_size, args, &nonce_values, &t);
if (result != OEMCrypto_SUCCESS) {
return;
}
std::string oemcrypto_core_message;
if (!kdo_fun(args, t, &oemcrypto_core_message)) {
return;
}
}
/**
* Template arguments:
* T: kdo deserialize output/odk serialize input structure
* F: kdo deserialize function
* G: odk serialize function
*
* raw bytes -> F deserialize -> struct T -> G serialize -> raw bytes
*/
template <typename T, typename F, typename G>
static void kdo_odk(const F& kdo_fun, const G& odk_fun, const uint8_t* in,
size_t size, const size_t clock_value_size, uint8_t* out) {
if (size <= clock_value_size) {
return;
}
// Input byte array format: [Clock Values][data to parse].
// Only Renewal Request expects clock values to be present.
std::string input(reinterpret_cast<const char*>(in) + clock_value_size,
size - clock_value_size);
T t = {};
if (!kdo_fun(input, &t)) {
return;
}
ODK_NonceValues nonce_values = {t.api_minor_version, t.api_major_version,
t.nonce, t.session_id};
OEMCryptoResult err = odk_fun(in, out, &size, t, &nonce_values);
if (OEMCrypto_SUCCESS != err) {
return;
}
}
} // namespace oemcrypto_core_message
#endif // WIDEVINE_ODK_TEST_FUZZING_ODK_FUZZ_HELPER_H_