diff --git a/src/test/fuzz/util/net.cpp b/src/test/fuzz/util/net.cpp index 99151bb84d5..5e7aae670ee 100644 --- a/src/test/fuzz/util/net.cpp +++ b/src/test/fuzz/util/net.cpp @@ -193,21 +193,20 @@ ssize_t FuzzedSock::Recv(void* buf, size_t len, int flags) const 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()}); + random_bytes = 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(1); + random_bytes = ConsumeRandomLengthByteVector(m_fuzzed_data_provider, len); if (!random_bytes.empty()) { - m_peek_data = random_bytes[0]; + m_peek_data = random_bytes; pad_to_len_bytes = false; } } else { - random_bytes = m_fuzzed_data_provider.ConsumeBytes( - m_fuzzed_data_provider.ConsumeIntegralInRange(0, len)); + random_bytes = ConsumeRandomLengthByteVector(m_fuzzed_data_provider, len); } if (random_bytes.empty()) { const ssize_t r = m_fuzzed_data_provider.ConsumeBool() ? 0 : -1; @@ -216,7 +215,11 @@ ssize_t FuzzedSock::Recv(void* buf, size_t len, int flags) const } return r; } - std::memcpy(buf, random_bytes.data(), random_bytes.size()); + // `random_bytes` might exceed the size of `buf` if e.g. Recv is called with + // len=N and MSG_PEEK first and afterwards called with len=M (M < N) and + // without MSG_PEEK. + size_t recv_len{std::min(random_bytes.size(), len)}; + std::memcpy(buf, random_bytes.data(), recv_len); if (pad_to_len_bytes) { if (len > random_bytes.size()) { std::memset((char*)buf + random_bytes.size(), 0, len - random_bytes.size()); @@ -226,7 +229,7 @@ ssize_t FuzzedSock::Recv(void* buf, size_t len, int flags) const 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(); + return recv_len; } int FuzzedSock::Connect(const sockaddr*, socklen_t) const @@ -380,7 +383,10 @@ bool FuzzedSock::Wait(std::chrono::milliseconds timeout, Event requested, Event* return false; } if (occurred != nullptr) { - *occurred = m_fuzzed_data_provider.ConsumeBool() ? requested : 0; + // We simulate the requested event as occured when ConsumeBool() + // returns false. This avoids simulating endless waiting if the + // FuzzedDataProvider runs out of data. + *occurred = m_fuzzed_data_provider.ConsumeBool() ? 0 : requested; } return true; } @@ -389,7 +395,10 @@ bool FuzzedSock::WaitMany(std::chrono::milliseconds timeout, EventsPerSock& even { for (auto& [sock, events] : events_per_sock) { (void)sock; - events.occurred = m_fuzzed_data_provider.ConsumeBool() ? events.requested : 0; + // We simulate the requested event as occured when ConsumeBool() + // returns false. This avoids simulating endless waiting if the + // FuzzedDataProvider runs out of data. + events.occurred = m_fuzzed_data_provider.ConsumeBool() ? 0 : events.requested; } return true; } diff --git a/src/test/fuzz/util/net.h b/src/test/fuzz/util/net.h index a6c9e23f2e4..ed026806763 100644 --- a/src/test/fuzz/util/net.h +++ b/src/test/fuzz/util/net.h @@ -43,7 +43,7 @@ class FuzzedSock : public Sock * If `MSG_PEEK` is used, then our `Recv()` returns some random data as usual, but on the next * `Recv()` call we must return the same data, thus we remember it here. */ - mutable std::optional m_peek_data; + mutable std::optional> m_peek_data; /** * Whether to pretend that the socket is select(2)-able. This is randomly set in the