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Merge #19107: p2p: Move all header verification into the network layer, extend logging

Browse Source 
deb52711a1 Remove header checks out of net_processing (Troy Giorshev)
52d4ae46ab Give V1TransportDeserializer CChainParams& member (Troy Giorshev)
5bceef6b12 Change CMessageHeader Constructor (Troy Giorshev)
1ca20c1af8 Add doxygen comment for ReceiveMsgBytes (Troy Giorshev)
890b1d7c2b Move checksum check from net_processing to net (Troy Giorshev)
2716647ebf Give V1TransportDeserializer an m_node_id member (Troy Giorshev)

Pull request description:

  Inspired by #15206 and #15197, this PR moves all message header verification from the message processing layer and into the network/transport layer.

  In the previous PRs there is a change in behavior, where we would disconnect from peers upon a single failed checksum check.  In various discussions there was concern over whether this was the right choice, and some expressed a desire to see how this would look if it was made to be a pure refactor.

  For more context, see https://bitcoincore.reviews/15206.html#l-81.

  This PR improves the separation between the p2p layers, helping improvements like [BIP324](https://github.com/bitcoin/bitcoin/pull/18242) and #18989.

ACKs for top commit:
  ryanofsky:
    Code review ACK deb52711a1 just rebase due to conflict on adjacent line
  jnewbery:
    Code review ACK deb52711a1.

Tree-SHA512: 1a3b7ae883b020cfee1bef968813e04df651ffdad9dd961a826bd80654f2c98676ce7f4721038a1b78d8790e4cebe8060419e3d8affc97ce2b9b4e4b72e6fa9f
This commit is contained in:
fanquake
2020-09-29 15:50:03 +08:00
parent e36aa351a3 deb52711a1
commit 6af9b31bfc
8 changed files with 99 additions and 109 deletions
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82
src/net.cpp
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@@ -10,7 +10,6 @@
#include <net.h>
#include <banman.h>
#include <chainparams.h>
#include <clientversion.h>
#include <consensus/consensus.h>
#include <crypto/sha256.h>
@@ -607,6 +606,16 @@ void CNode::copyStats(CNodeStats &stats, const std::vector<bool> &m_asmap)
}
#undef X
/**
* Receive bytes from the buffer and deserialize them into messages.
*
* @param[in] pch A pointer to the raw data
* @param[in] nBytes Size of the data
* @param[out] complete Set True if at least one message has been
* deserialized and is ready to be processed
* @return True if the peer should stay connected,
* False if the peer should be disconnected from.
*/
bool CNode::ReceiveMsgBytes(const char *pch, unsigned int nBytes, bool& complete)
{
complete = false;
@@ -617,25 +626,35 @@ bool CNode::ReceiveMsgBytes(const char *pch, unsigned int nBytes, bool& complete
while (nBytes > 0) {
// absorb network data
int handled = m_deserializer->Read(pch, nBytes);
if (handled < 0) return false;
if (handled < 0) {
// Serious header problem, disconnect from the peer.
return false;
}
pch += handled;
nBytes -= handled;
if (m_deserializer->Complete()) {
// decompose a transport agnostic CNetMessage from the deserializer
CNetMessage msg = m_deserializer->GetMessage(Params().MessageStart(), time);
uint32_t out_err_raw_size{0};
Optional<CNetMessage> result{m_deserializer->GetMessage(time, out_err_raw_size)};
if (!result) {
// 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;
continue;
}
//store received bytes per message command
//to prevent a memory DOS, only allow valid commands
mapMsgCmdSize::iterator i = mapRecvBytesPerMsgCmd.find(msg.m_command);
mapMsgCmdSize::iterator i = mapRecvBytesPerMsgCmd.find(result->m_command);
if (i == mapRecvBytesPerMsgCmd.end())
i = mapRecvBytesPerMsgCmd.find(NET_MESSAGE_COMMAND_OTHER);
assert(i != mapRecvBytesPerMsgCmd.end());
i->second += msg.m_raw_message_size;
i->second += result->m_raw_message_size;
// push the message to the process queue,
vRecvMsg.push_back(std::move(msg));
vRecvMsg.push_back(std::move(*result));
complete = true;
}
@@ -662,11 +681,19 @@ int V1TransportDeserializer::readHeader(const char *pch, unsigned int nBytes)
hdrbuf >> hdr;
}
catch (const std::exception&) {
LogPrint(BCLog::NET, "HEADER ERROR - UNABLE TO DESERIALIZE, peer=%d\n", m_node_id);
return -1;
}
// Check start string, network magic
if (memcmp(hdr.pchMessageStart, m_chain_params.MessageStart(), CMessageHeader::MESSAGE_START_SIZE) != 0) {
LogPrint(BCLog::NET, "HEADER ERROR - MESSAGESTART (%s, %u bytes), received %s, peer=%d\n", hdr.GetCommand(), hdr.nMessageSize, HexStr(hdr.pchMessageStart), m_node_id);
return -1;
}
// reject messages larger than MAX_SIZE or MAX_PROTOCOL_MESSAGE_LENGTH
if (hdr.nMessageSize > MAX_SIZE || hdr.nMessageSize > MAX_PROTOCOL_MESSAGE_LENGTH) {
LogPrint(BCLog::NET, "HEADER ERROR - SIZE (%s, %u bytes), peer=%d\n", hdr.GetCommand(), hdr.nMessageSize, m_node_id);
return -1;
}
@@ -701,36 +728,39 @@ const uint256& V1TransportDeserializer::GetMessageHash() const
return data_hash;
}
CNetMessage V1TransportDeserializer::GetMessage(const CMessageHeader::MessageStartChars& message_start, const std::chrono::microseconds time)
Optional<CNetMessage> V1TransportDeserializer::GetMessage(const std::chrono::microseconds time, uint32_t& out_err_raw_size)
{
// decompose a single CNetMessage from the TransportDeserializer
CNetMessage msg(std::move(vRecv));
Optional<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;
// store state about valid header, netmagic and checksum
msg.m_valid_header = hdr.IsValid(message_start);
msg.m_valid_netmagic = (memcmp(hdr.pchMessageStart, message_start, CMessageHeader::MESSAGE_START_SIZE) == 0);
uint256 hash = GetMessageHash();
// store command string, payload size
msg.m_command = hdr.GetCommand();
msg.m_message_size = hdr.nMessageSize;
msg.m_raw_message_size = hdr.nMessageSize + CMessageHeader::HEADER_SIZE;
// We just received a message off the wire, harvest entropy from the time (and the message checksum)
RandAddEvent(ReadLE32(hash.begin()));
msg.m_valid_checksum = (memcmp(hash.begin(), hdr.pchChecksum, CMessageHeader::CHECKSUM_SIZE) == 0);
if (!msg.m_valid_checksum) {
LogPrint(BCLog::NET, "CHECKSUM ERROR (%s, %u bytes), expected %s was %s\n",
SanitizeString(msg.m_command), msg.m_message_size,
// Check checksum and header command string
if (memcmp(hash.begin(), hdr.pchChecksum, CMessageHeader::CHECKSUM_SIZE) != 0) {
LogPrint(BCLog::NET, "CHECKSUM ERROR (%s, %u bytes), expected %s was %s, peer=%d\n",
SanitizeString(msg->m_command), msg->m_message_size,
HexStr(Span<uint8_t>(hash.begin(), hash.begin() + CMessageHeader::CHECKSUM_SIZE)),
HexStr(hdr.pchChecksum));
HexStr(hdr.pchChecksum),
m_node_id);
out_err_raw_size = msg->m_raw_message_size;
msg = nullopt;
} else if (!hdr.IsCommandValid()) {
LogPrint(BCLog::NET, "HEADER ERROR - COMMAND (%s, %u bytes), peer=%d\n",
hdr.GetCommand(), msg->m_message_size, m_node_id);
out_err_raw_size = msg->m_raw_message_size;
msg = nullopt;
}
// store receive time
msg.m_time = time;
// reset the network deserializer (prepare for the next message)
// Always reset the network deserializer (prepare for the next message)
Reset();
return msg;
}
@@ -2850,7 +2880,7 @@ CNode::CNode(NodeId idIn, ServiceFlags nLocalServicesIn, int nMyStartingHeightIn
LogPrint(BCLog::NET, "Added connection peer=%d\n", id);
}
m_deserializer = MakeUnique<V1TransportDeserializer>(V1TransportDeserializer(Params().MessageStart(), SER_NETWORK, INIT_PROTO_VERSION));
m_deserializer = MakeUnique<V1TransportDeserializer>(V1TransportDeserializer(Params(), GetId(), SER_NETWORK, INIT_PROTO_VERSION));
m_serializer = MakeUnique<V1TransportSerializer>(V1TransportSerializer());
}