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// Copyright (c) 2021 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 <test/fuzz/util.h>
#include <test/util/script.h>
#include <util/rbf.h>
#include <util/time.h>
#include <version.h>
FuzzedSock::FuzzedSock(FuzzedDataProvider& fuzzed_data_provider)
: m_fuzzed_data_provider{fuzzed_data_provider}
{
m_socket = fuzzed_data_provider.ConsumeIntegralInRange<SOCKET>(INVALID_SOCKET - 1, INVALID_SOCKET);
}
FuzzedSock::~FuzzedSock()
{
// Sock::~Sock() will be called after FuzzedSock::~FuzzedSock() and it will call
// Sock::Reset() (not FuzzedSock::Reset()!) which will call CloseSocket(m_socket).
// Avoid closing an arbitrary file descriptor (m_socket is just a random very high number which
// theoretically may concide with a real opened file descriptor).
Reset();
}
FuzzedSock& FuzzedSock::operator=(Sock&& other)
{
assert(false && "Move of Sock into FuzzedSock not allowed.");
return *this;
}
void FuzzedSock::Reset()
{
m_socket = INVALID_SOCKET;
}
ssize_t FuzzedSock::Send(const void* data, size_t len, int flags) const
{
constexpr std::array send_errnos{
EACCES,
EAGAIN,
EALREADY,
EBADF,
ECONNRESET,
EDESTADDRREQ,
EFAULT,
EINTR,
EINVAL,
EISCONN,
EMSGSIZE,
ENOBUFS,
ENOMEM,
ENOTCONN,
ENOTSOCK,
EOPNOTSUPP,
EPIPE,
EWOULDBLOCK,
};
if (m_fuzzed_data_provider.ConsumeBool()) {
return len;
}
const ssize_t r = m_fuzzed_data_provider.ConsumeIntegralInRange<ssize_t>(-1, len);
if (r == -1) {
SetFuzzedErrNo(m_fuzzed_data_provider, send_errnos);
}
return r;
}
ssize_t FuzzedSock::Recv(void* buf, size_t len, int flags) const
{
// Have a permanent error at recv_errnos[0] because when the fuzzed data is exhausted
// SetFuzzedErrNo() will always return the first element and we want to avoid Recv()
// returning -1 and setting errno to EAGAIN repeatedly.
constexpr std::array recv_errnos{
ECONNREFUSED,
EAGAIN,
EBADF,
EFAULT,
EINTR,
EINVAL,
ENOMEM,
ENOTCONN,
ENOTSOCK,
EWOULDBLOCK,
};
assert(buf != nullptr || len == 0);
if (len == 0 || m_fuzzed_data_provider.ConsumeBool()) {
const ssize_t r = m_fuzzed_data_provider.ConsumeBool() ? 0 : -1;
if (r == -1) {
SetFuzzedErrNo(m_fuzzed_data_provider, recv_errnos);
}
return r;
}
std::vector<uint8_t> random_bytes;
bool pad_to_len_bytes{m_fuzzed_data_provider.ConsumeBool()};
if (m_peek_data.has_value()) {
// `MSG_PEEK` was used in the preceding `Recv()` call, return `m_peek_data`.
random_bytes.assign({m_peek_data.value()});
if ((flags & MSG_PEEK) == 0) {
m_peek_data.reset();
}
pad_to_len_bytes = false;
} else if ((flags & MSG_PEEK) != 0) {
// New call with `MSG_PEEK`.
random_bytes = m_fuzzed_data_provider.ConsumeBytes<uint8_t>(1);
if (!random_bytes.empty()) {
m_peek_data = random_bytes[0];
pad_to_len_bytes = false;
}
} else {
random_bytes = m_fuzzed_data_provider.ConsumeBytes<uint8_t>(
m_fuzzed_data_provider.ConsumeIntegralInRange<size_t>(0, len));
}
if (random_bytes.empty()) {
const ssize_t r = m_fuzzed_data_provider.ConsumeBool() ? 0 : -1;
if (r == -1) {
SetFuzzedErrNo(m_fuzzed_data_provider, recv_errnos);
}
return r;
}
std::memcpy(buf, random_bytes.data(), random_bytes.size());
if (pad_to_len_bytes) {
if (len > random_bytes.size()) {
std::memset((char*)buf + random_bytes.size(), 0, len - random_bytes.size());
}
return len;
}
if (m_fuzzed_data_provider.ConsumeBool() && std::getenv("FUZZED_SOCKET_FAKE_LATENCY") != nullptr) {
std::this_thread::sleep_for(std::chrono::milliseconds{2});
}
return random_bytes.size();
}
int FuzzedSock::Connect(const sockaddr*, socklen_t) const
{
// Have a permanent error at connect_errnos[0] because when the fuzzed data is exhausted
// SetFuzzedErrNo() will always return the first element and we want to avoid Connect()
// returning -1 and setting errno to EAGAIN repeatedly.
constexpr std::array connect_errnos{
ECONNREFUSED,
EAGAIN,
ECONNRESET,
EHOSTUNREACH,
EINPROGRESS,
EINTR,
ENETUNREACH,
ETIMEDOUT,
};
if (m_fuzzed_data_provider.ConsumeBool()) {
SetFuzzedErrNo(m_fuzzed_data_provider, connect_errnos);
return -1;
}
return 0;
}
int FuzzedSock::GetSockOpt(int level, int opt_name, void* opt_val, socklen_t* opt_len) const
{
constexpr std::array getsockopt_errnos{
ENOMEM,
ENOBUFS,
};
if (m_fuzzed_data_provider.ConsumeBool()) {
SetFuzzedErrNo(m_fuzzed_data_provider, getsockopt_errnos);
return -1;
}
if (opt_val == nullptr) {
return 0;
}
std::memcpy(opt_val,
ConsumeFixedLengthByteVector(m_fuzzed_data_provider, *opt_len).data(),
*opt_len);
return 0;
}
bool FuzzedSock::Wait(std::chrono::milliseconds timeout, Event requested, Event* occurred) const
{
constexpr std::array wait_errnos{
EBADF,
EINTR,
EINVAL,
};
if (m_fuzzed_data_provider.ConsumeBool()) {
SetFuzzedErrNo(m_fuzzed_data_provider, wait_errnos);
return false;
}
if (occurred != nullptr) {
*occurred = m_fuzzed_data_provider.ConsumeBool() ? requested : 0;
}
return true;
}
bool FuzzedSock::IsConnected(std::string& errmsg) const
{
if (m_fuzzed_data_provider.ConsumeBool()) {
return true;
}
errmsg = "disconnected at random by the fuzzer";
return false;
}
void FillNode(FuzzedDataProvider& fuzzed_data_provider, CNode& node, bool init_version) noexcept
{
const ServiceFlags remote_services = ConsumeWeakEnum(fuzzed_data_provider, ALL_SERVICE_FLAGS);
const NetPermissionFlags permission_flags = ConsumeWeakEnum(fuzzed_data_provider, ALL_NET_PERMISSION_FLAGS);
const int32_t version = fuzzed_data_provider.ConsumeIntegralInRange<int32_t>(MIN_PEER_PROTO_VERSION, std::numeric_limits<int32_t>::max());
const bool filter_txs = fuzzed_data_provider.ConsumeBool();
node.nServices = remote_services;
node.m_permissionFlags = permission_flags;
if (init_version) {
node.nVersion = version;
node.SetCommonVersion(std::min(version, PROTOCOL_VERSION));
}
if (node.m_tx_relay != nullptr) {
LOCK(node.m_tx_relay->cs_filter);
node.m_tx_relay->fRelayTxes = filter_txs;
}
}
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 = ParseISO8601DateTime("1970-01-01T00:00:01Z");
static const int64_t time_max = ParseISO8601DateTime("9999-12-31T23:59:59Z");
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, /* max_length */ 128, /* 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 std::optional<size_t>& max_length, const bool maybe_p2wsh) noexcept
{
const std::vector<uint8_t> b = ConsumeRandomLengthByteVector(fuzzed_data_provider, max_length);
CScript r_script{b.begin(), b.end()};
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::SEQUENCE_FINAL - 1,
MAX_BIP125_RBF_SEQUENCE,
}) :
fuzzed_data_provider.ConsumeIntegral<uint32_t>();
}
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