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[net] Don't return an optional from TransportDeserializer::GetMessage()

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Also, access mapRecvBytesPerMsgCmd with `at()` not `find()`. This
throws an error if COMMAND_OTHER doesn't exist, which should never
happen. `find()` instead just accessed the last element, which could make
debugging more difficult.

Resolves review comments from PR19107:

- https://github.com/bitcoin/bitcoin/pull/19107#discussion_r478718436
- https://github.com/bitcoin/bitcoin/pull/19107#discussion_r478714497
This commit is contained in:
Troy Giorshev 2020-11-05 05:05:32 -05:00 committed by John Newbery
parent e35c4a3d80
commit 8c96008ab1
3 changed files with 34 additions and 35 deletions
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45
src/net.cpp
View File

@ -641,25 +641,26 @@ bool CNode::ReceiveMsgBytes(Span<const uint8_t> msg_bytes, bool& complete)
if (m_deserializer->Complete()) {
// decompose a transport agnostic CNetMessage from the deserializer
uint32_t out_err_raw_size{0};
std::optional<CNetMessage> result{m_deserializer->GetMessage(time, out_err_raw_size)};
if (!result) {
bool reject_message{false};
CNetMessage msg = m_deserializer->GetMessage(time, reject_message);
if (reject_message) {
// Message deserialization failed. Drop the message but don't disconnect the peer.
// store the size of the corrupt message
mapRecvBytesPerMsgCmd.find(NET_MESSAGE_COMMAND_OTHER)->second += out_err_raw_size;
mapRecvBytesPerMsgCmd.at(NET_MESSAGE_COMMAND_OTHER) += msg.m_raw_message_size;
continue;
}
//store received bytes per message command
//to prevent a memory DOS, only allow valid commands
mapMsgCmdSize::iterator i = mapRecvBytesPerMsgCmd.find(result->m_command);
if (i == mapRecvBytesPerMsgCmd.end())
// Store received bytes per message command
// to prevent a memory DOS, only allow valid commands
auto i = mapRecvBytesPerMsgCmd.find(msg.m_command);
if (i == mapRecvBytesPerMsgCmd.end()) {
i = mapRecvBytesPerMsgCmd.find(NET_MESSAGE_COMMAND_OTHER);
}
assert(i != mapRecvBytesPerMsgCmd.end());
i->second += result->m_raw_message_size;
i->second += msg.m_raw_message_size;
// push the message to the process queue,
vRecvMsg.push_back(std::move(*result));
vRecvMsg.push_back(std::move(msg));
complete = true;
}
@ -733,16 +734,18 @@ const uint256& V1TransportDeserializer::GetMessageHash() const
return data_hash;
}
std::optional<CNetMessage> V1TransportDeserializer::GetMessage(const std::chrono::microseconds time, uint32_t& out_err_raw_size)
CNetMessage V1TransportDeserializer::GetMessage(const std::chrono::microseconds time, bool& reject_message)
{
// Initialize out parameter
reject_message = false;
// decompose a single CNetMessage from the TransportDeserializer
std::optional<CNetMessage> msg(std::move(vRecv));
CNetMessage msg(std::move(vRecv));
// store command string, time, and sizes
msg->m_command = hdr.GetCommand();
msg->m_time = time;
msg->m_message_size = hdr.nMessageSize;
msg->m_raw_message_size = hdr.nMessageSize + CMessageHeader::HEADER_SIZE;
msg.m_command = hdr.GetCommand();
msg.m_time = time;
msg.m_message_size = hdr.nMessageSize;
msg.m_raw_message_size = hdr.nMessageSize + CMessageHeader::HEADER_SIZE;
uint256 hash = GetMessageHash();
@ -752,17 +755,15 @@ std::optional<CNetMessage> V1TransportDeserializer::GetMessage(const std::chrono
// Check checksum and header command string
if (memcmp(hash.begin(), hdr.pchChecksum, CMessageHeader::CHECKSUM_SIZE) != 0) {
LogPrint(BCLog::NET, "Header error: Wrong checksum (%s, %u bytes), expected %s was %s, peer=%d\n",
SanitizeString(msg->m_command), msg->m_message_size,
SanitizeString(msg.m_command), msg.m_message_size,
HexStr(Span<uint8_t>(hash.begin(), hash.begin() + CMessageHeader::CHECKSUM_SIZE)),
HexStr(hdr.pchChecksum),
m_node_id);
out_err_raw_size = msg->m_raw_message_size;
msg = std::nullopt;
reject_message = true;
} else if (!hdr.IsCommandValid()) {
LogPrint(BCLog::NET, "Header error: Invalid message type (%s, %u bytes), peer=%d\n",
SanitizeString(hdr.GetCommand()), msg->m_message_size, m_node_id);
out_err_raw_size = msg->m_raw_message_size;
msg.reset();
SanitizeString(hdr.GetCommand()), msg.m_message_size, m_node_id);
reject_message = true;
}
// Always reset the network deserializer (prepare for the next message)

4
src/net.h
View File

@ -309,7 +309,7 @@ public:
/** read and deserialize data, advances msg_bytes data pointer */
virtual int Read(Span<const uint8_t>& msg_bytes) = 0;
// decomposes a message from the context
virtual std::optional<CNetMessage> GetMessage(std::chrono::microseconds time, uint32_t& out_err) = 0;
virtual CNetMessage GetMessage(std::chrono::microseconds time, bool& reject_message) = 0;
virtual ~TransportDeserializer() {}
};
@ -373,7 +373,7 @@ public:
}
return ret;
}
std::optional<CNetMessage> GetMessage(std::chrono::microseconds time, uint32_t& out_err_raw_size) override;
CNetMessage GetMessage(std::chrono::microseconds time, bool& reject_message) override;
};
/** The TransportSerializer prepares messages for the network transport

20
src/test/fuzz/p2p_transport_serialization.cpp
View File

@ -68,18 +68,16 @@ FUZZ_TARGET_INIT(p2p_transport_serialization, initialize_p2p_transport_serializa
}
if (deserializer.Complete()) {
const std::chrono::microseconds m_time{std::numeric_limits<int64_t>::max()};
uint32_t out_err_raw_size{0};
std::optional<CNetMessage> result{deserializer.GetMessage(m_time, out_err_raw_size)};
if (result) {
assert(result->m_command.size() <= CMessageHeader::COMMAND_SIZE);
assert(result->m_raw_message_size <= mutable_msg_bytes.size());
assert(result->m_raw_message_size == CMessageHeader::HEADER_SIZE + result->m_message_size);
assert(result->m_time == m_time);
bool reject_message{false};
CNetMessage msg = deserializer.GetMessage(m_time, reject_message);
assert(msg.m_command.size() <= CMessageHeader::COMMAND_SIZE);
assert(msg.m_raw_message_size <= mutable_msg_bytes.size());
assert(msg.m_raw_message_size == CMessageHeader::HEADER_SIZE + msg.m_message_size);
assert(msg.m_time == m_time);
std::vector<unsigned char> header;
auto msg = CNetMsgMaker{result->m_recv.GetVersion()}.Make(result->m_command, MakeUCharSpan(result->m_recv));
serializer.prepareForTransport(msg, header);
}
std::vector<unsigned char> header;
auto msg2 = CNetMsgMaker{msg.m_recv.GetVersion()}.Make(msg.m_command, MakeUCharSpan(msg.m_recv));
serializer.prepareForTransport(msg2, header);
}
}
}