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// Copyright (c) 2021-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <consensus/amount.h>
#include <pubkey.h>
#include <test/fuzz/util.h>
#include <test/util/script.h>
#include <util/check.h>
#include <util/overflow.h>
#include <util/rbf.h>
#include <util/time.h>
#include <version.h>
#include <memory>
CAmount ConsumeMoney(FuzzedDataProvider& fuzzed_data_provider, const std::optional<CAmount>& max) noexcept
{
return fuzzed_data_provider.ConsumeIntegralInRange<CAmount>(0, max.value_or(MAX_MONEY));
}
int64_t ConsumeTime(FuzzedDataProvider& fuzzed_data_provider, const std::optional<int64_t>& min, const std::optional<int64_t>& max) noexcept
{
// Avoid t=0 (1970-01-01T00:00:00Z) since SetMockTime(0) disables mocktime.
static const int64_t time_min{946684801}; // 2000-01-01T00:00:01Z
static const int64_t time_max{4133980799}; // 2100-12-31T23:59:59Z
return fuzzed_data_provider.ConsumeIntegralInRange<int64_t>(min.value_or(time_min), max.value_or(time_max));
}
CMutableTransaction ConsumeTransaction(FuzzedDataProvider& fuzzed_data_provider, const std::optional<std::vector<uint256>>& prevout_txids, const int max_num_in, const int max_num_out) noexcept
{
CMutableTransaction tx_mut;
const auto p2wsh_op_true = fuzzed_data_provider.ConsumeBool();
tx_mut.nVersion = fuzzed_data_provider.ConsumeBool() ?
CTransaction::CURRENT_VERSION :
fuzzed_data_provider.ConsumeIntegral<int32_t>();
tx_mut.nLockTime = fuzzed_data_provider.ConsumeIntegral<uint32_t>();
const auto num_in = fuzzed_data_provider.ConsumeIntegralInRange<int>(0, max_num_in);
const auto num_out = fuzzed_data_provider.ConsumeIntegralInRange<int>(0, max_num_out);
for (int i = 0; i < num_in; ++i) {
const auto& txid_prev = prevout_txids ?
PickValue(fuzzed_data_provider, *prevout_txids) :
ConsumeUInt256(fuzzed_data_provider);
const auto index_out = fuzzed_data_provider.ConsumeIntegralInRange<uint32_t>(0, max_num_out);
const auto sequence = ConsumeSequence(fuzzed_data_provider);
const auto script_sig = p2wsh_op_true ? CScript{} : ConsumeScript(fuzzed_data_provider);
CScriptWitness script_wit;
if (p2wsh_op_true) {
script_wit.stack = std::vector<std::vector<uint8_t>>{WITNESS_STACK_ELEM_OP_TRUE};
} else {
script_wit = ConsumeScriptWitness(fuzzed_data_provider);
}
CTxIn in;
in.prevout = COutPoint{txid_prev, index_out};
in.nSequence = sequence;
in.scriptSig = script_sig;
in.scriptWitness = script_wit;
tx_mut.vin.push_back(in);
}
for (int i = 0; i < num_out; ++i) {
const auto amount = fuzzed_data_provider.ConsumeIntegralInRange<CAmount>(-10, 50 * COIN + 10);
const auto script_pk = p2wsh_op_true ?
P2WSH_OP_TRUE :
ConsumeScript(fuzzed_data_provider, /*maybe_p2wsh=*/true);
tx_mut.vout.emplace_back(amount, script_pk);
}
return tx_mut;
}
CScriptWitness ConsumeScriptWitness(FuzzedDataProvider& fuzzed_data_provider, const size_t max_stack_elem_size) noexcept
{
CScriptWitness ret;
const auto n_elements = fuzzed_data_provider.ConsumeIntegralInRange<size_t>(0, max_stack_elem_size);
for (size_t i = 0; i < n_elements; ++i) {
ret.stack.push_back(ConsumeRandomLengthByteVector(fuzzed_data_provider));
}
return ret;
}
CScript ConsumeScript(FuzzedDataProvider& fuzzed_data_provider, const bool maybe_p2wsh) noexcept
{
CScript r_script{};
{
// Keep a buffer of bytes to allow the fuzz engine to produce smaller
// inputs to generate CScripts with repeated data.
static constexpr unsigned MAX_BUFFER_SZ{128};
std::vector<uint8_t> buffer(MAX_BUFFER_SZ, uint8_t{'a'});
while (fuzzed_data_provider.ConsumeBool()) {
CallOneOf(
fuzzed_data_provider,
[&] {
// Insert byte vector directly to allow malformed or unparsable scripts
r_script.insert(r_script.end(), buffer.begin(), buffer.begin() + fuzzed_data_provider.ConsumeIntegralInRange(0U, MAX_BUFFER_SZ));
},
[&] {
// Push a byte vector from the buffer
r_script << std::vector<uint8_t>{buffer.begin(), buffer.begin() + fuzzed_data_provider.ConsumeIntegralInRange(0U, MAX_BUFFER_SZ)};
},
[&] {
// Push multisig
// There is a special case for this to aid the fuzz engine
// navigate the highly structured multisig format.
r_script << fuzzed_data_provider.ConsumeIntegralInRange<int64_t>(0, 22);
int num_data{fuzzed_data_provider.ConsumeIntegralInRange(1, 22)};
std::vector<uint8_t> pubkey_comp{buffer.begin(), buffer.begin() + CPubKey::COMPRESSED_SIZE};
pubkey_comp.front() = fuzzed_data_provider.ConsumeIntegralInRange(2, 3); // Set first byte for GetLen() to pass
std::vector<uint8_t> pubkey_uncomp{buffer.begin(), buffer.begin() + CPubKey::SIZE};
pubkey_uncomp.front() = fuzzed_data_provider.ConsumeIntegralInRange(4, 7); // Set first byte for GetLen() to pass
while (num_data--) {
auto& pubkey{fuzzed_data_provider.ConsumeBool() ? pubkey_uncomp : pubkey_comp};
if (fuzzed_data_provider.ConsumeBool()) {
pubkey.back() = num_data; // Make each pubkey different
}
r_script << pubkey;
}
r_script << fuzzed_data_provider.ConsumeIntegralInRange<int64_t>(0, 22);
},
[&] {
// Mutate the buffer
const auto vec{ConsumeRandomLengthByteVector(fuzzed_data_provider, /*max_length=*/MAX_BUFFER_SZ)};
std::copy(vec.begin(), vec.end(), buffer.begin());
},
[&] {
// Push an integral
r_script << fuzzed_data_provider.ConsumeIntegral<int64_t>();
},
[&] {
// Push an opcode
r_script << ConsumeOpcodeType(fuzzed_data_provider);
},
[&] {
// Push a scriptnum
r_script << ConsumeScriptNum(fuzzed_data_provider);
});
}
}
if (maybe_p2wsh && fuzzed_data_provider.ConsumeBool()) {
uint256 script_hash;
CSHA256().Write(r_script.data(), r_script.size()).Finalize(script_hash.begin());
r_script.clear();
r_script << OP_0 << ToByteVector(script_hash);
}
return r_script;
}
uint32_t ConsumeSequence(FuzzedDataProvider& fuzzed_data_provider) noexcept
{
return fuzzed_data_provider.ConsumeBool() ?
fuzzed_data_provider.PickValueInArray({
CTxIn::SEQUENCE_FINAL,
CTxIn::MAX_SEQUENCE_NONFINAL,
MAX_BIP125_RBF_SEQUENCE,
}) :
fuzzed_data_provider.ConsumeIntegral<uint32_t>();
}
CTxDestination ConsumeTxDestination(FuzzedDataProvider& fuzzed_data_provider) noexcept
{
CTxDestination tx_destination;
const size_t call_size{CallOneOf(
fuzzed_data_provider,
[&] {
tx_destination = CNoDestination{};
},
[&] {
tx_destination = PKHash{ConsumeUInt160(fuzzed_data_provider)};
},
[&] {
tx_destination = ScriptHash{ConsumeUInt160(fuzzed_data_provider)};
},
[&] {
tx_destination = WitnessV0ScriptHash{ConsumeUInt256(fuzzed_data_provider)};
},
[&] {
tx_destination = WitnessV0KeyHash{ConsumeUInt160(fuzzed_data_provider)};
},
[&] {
tx_destination = WitnessV1Taproot{XOnlyPubKey{ConsumeUInt256(fuzzed_data_provider)}};
},
[&] {
WitnessUnknown witness_unknown{};
witness_unknown.version = fuzzed_data_provider.ConsumeIntegralInRange(2, 16);
std::vector<uint8_t> witness_unknown_program_1{fuzzed_data_provider.ConsumeBytes<uint8_t>(40)};
if (witness_unknown_program_1.size() < 2) {
witness_unknown_program_1 = {0, 0};
}
witness_unknown.length = witness_unknown_program_1.size();
std::copy(witness_unknown_program_1.begin(), witness_unknown_program_1.end(), witness_unknown.program);
tx_destination = witness_unknown;
})};
Assert(call_size == std::variant_size_v<CTxDestination>);
return tx_destination;
}
CKey ConsumePrivateKey(FuzzedDataProvider& fuzzed_data_provider, std::optional<bool> compressed) noexcept
{
auto key_data = fuzzed_data_provider.ConsumeBytes<uint8_t>(32);
key_data.resize(32);
CKey key;
bool compressed_value = compressed ? *compressed : fuzzed_data_provider.ConsumeBool();
key.Set(key_data.begin(), key_data.end(), compressed_value);
return key;
}
bool ContainsSpentInput(const CTransaction& tx, const CCoinsViewCache& inputs) noexcept
{
for (const CTxIn& tx_in : tx.vin) {
const Coin& coin = inputs.AccessCoin(tx_in.prevout);
if (coin.IsSpent()) {
return true;
}
}
return false;
}
FILE* FuzzedFileProvider::open()
{
SetFuzzedErrNo(m_fuzzed_data_provider);
if (m_fuzzed_data_provider.ConsumeBool()) {
return nullptr;
}
std::string mode;
CallOneOf(
m_fuzzed_data_provider,
[&] {
mode = "r";
},
[&] {
mode = "r+";
},
[&] {
mode = "w";
},
[&] {
mode = "w+";
},
[&] {
mode = "a";
},
[&] {
mode = "a+";
});
#if defined _GNU_SOURCE && !defined __ANDROID__
const cookie_io_functions_t io_hooks = {
FuzzedFileProvider::read,
FuzzedFileProvider::write,
FuzzedFileProvider::seek,
FuzzedFileProvider::close,
};
return fopencookie(this, mode.c_str(), io_hooks);
#else
(void)mode;
return nullptr;
#endif
}
ssize_t FuzzedFileProvider::read(void* cookie, char* buf, size_t size)
{
FuzzedFileProvider* fuzzed_file = (FuzzedFileProvider*)cookie;
SetFuzzedErrNo(fuzzed_file->m_fuzzed_data_provider);
if (buf == nullptr || size == 0 || fuzzed_file->m_fuzzed_data_provider.ConsumeBool()) {
return fuzzed_file->m_fuzzed_data_provider.ConsumeBool() ? 0 : -1;
}
const std::vector<uint8_t> random_bytes = fuzzed_file->m_fuzzed_data_provider.ConsumeBytes<uint8_t>(size);
if (random_bytes.empty()) {
return 0;
}
std::memcpy(buf, random_bytes.data(), random_bytes.size());
if (AdditionOverflow(fuzzed_file->m_offset, (int64_t)random_bytes.size())) {
return fuzzed_file->m_fuzzed_data_provider.ConsumeBool() ? 0 : -1;
}
fuzzed_file->m_offset += random_bytes.size();
return random_bytes.size();
}
ssize_t FuzzedFileProvider::write(void* cookie, const char* buf, size_t size)
{
FuzzedFileProvider* fuzzed_file = (FuzzedFileProvider*)cookie;
SetFuzzedErrNo(fuzzed_file->m_fuzzed_data_provider);
const ssize_t n = fuzzed_file->m_fuzzed_data_provider.ConsumeIntegralInRange<ssize_t>(0, size);
if (AdditionOverflow(fuzzed_file->m_offset, (int64_t)n)) {
return 0;
}
fuzzed_file->m_offset += n;
return n;
}
int FuzzedFileProvider::seek(void* cookie, int64_t* offset, int whence)
{
assert(whence == SEEK_SET || whence == SEEK_CUR || whence == SEEK_END);
FuzzedFileProvider* fuzzed_file = (FuzzedFileProvider*)cookie;
SetFuzzedErrNo(fuzzed_file->m_fuzzed_data_provider);
int64_t new_offset = 0;
if (whence == SEEK_SET) {
new_offset = *offset;
} else if (whence == SEEK_CUR) {
if (AdditionOverflow(fuzzed_file->m_offset, *offset)) {
return -1;
}
new_offset = fuzzed_file->m_offset + *offset;
} else if (whence == SEEK_END) {
const int64_t n = fuzzed_file->m_fuzzed_data_provider.ConsumeIntegralInRange<int64_t>(0, 4096);
if (AdditionOverflow(n, *offset)) {
return -1;
}
new_offset = n + *offset;
}
if (new_offset < 0) {
return -1;
}
fuzzed_file->m_offset = new_offset;
*offset = new_offset;
return fuzzed_file->m_fuzzed_data_provider.ConsumeIntegralInRange<int>(-1, 0);
}
int FuzzedFileProvider::close(void* cookie)
{
FuzzedFileProvider* fuzzed_file = (FuzzedFileProvider*)cookie;
SetFuzzedErrNo(fuzzed_file->m_fuzzed_data_provider);
return fuzzed_file->m_fuzzed_data_provider.ConsumeIntegralInRange<int>(-1, 0);
}
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