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cryptonote_protocol: some stricter checks on object requests #6554

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merged 2 commits into from
May 19, 2020
Merged

cryptonote_protocol: some stricter checks on object requests #6554

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f01d529
cryptonote_protocol: reject requests/notifications before handshake
moneromooo-monero May 17, 2020
bbab044
cryptonote_protocol: stricter limit to number of objects requested
moneromooo-monero May 17, 2020
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3 changes: 2 additions & 1 deletion src/cryptonote_protocol/cryptonote_protocol_handler.h
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Original file line number Diff line number Diff line change
Expand Up @@ -51,7 +51,8 @@ PUSH_WARNINGS
DISABLE_VS_WARNINGS(4355)

#define LOCALHOST_INT 2130706433
#define CURRENCY_PROTOCOL_MAX_OBJECT_REQUEST_COUNT 500
#define CURRENCY_PROTOCOL_MAX_OBJECT_REQUEST_COUNT 100
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I bet 500 blocks limit works pretty well. Any good reason to change this?

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To mitigate DoS potential, as above. 100 objects are smaller than 500 (ceteris paribus).

static_assert(CURRENCY_PROTOCOL_MAX_OBJECT_REQUEST_COUNT >= BLOCKS_SYNCHRONIZING_DEFAULT_COUNT_PRE_V4, "Invalid CURRENCY_PROTOCOL_MAX_OBJECT_REQUEST_COUNT");

namespace cryptonote
{
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20 changes: 20 additions & 0 deletions src/cryptonote_protocol/cryptonote_protocol_handler.inl
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Expand Up @@ -793,6 +793,12 @@ namespace cryptonote
int t_cryptonote_protocol_handler<t_core>::handle_request_fluffy_missing_tx(int command, NOTIFY_REQUEST_FLUFFY_MISSING_TX::request& arg, cryptonote_connection_context& context)
{
MLOG_P2P_MESSAGE("Received NOTIFY_REQUEST_FLUFFY_MISSING_TX (" << arg.missing_tx_indices.size() << " txes), block hash " << arg.block_hash);
if (context.m_state == cryptonote_connection_context::state_before_handshake)
{
LOG_ERROR_CCONTEXT("Requested fluffy tx before handshake, dropping connection");
drop_connection(context, false, false);
return 1;
}

std::vector<std::pair<cryptonote::blobdata, block>> local_blocks;
std::vector<cryptonote::blobdata> local_txs;
Expand Down Expand Up @@ -884,6 +890,8 @@ namespace cryptonote
int t_cryptonote_protocol_handler<t_core>::handle_notify_get_txpool_complement(int command, NOTIFY_GET_TXPOOL_COMPLEMENT::request& arg, cryptonote_connection_context& context)
{
MLOG_P2P_MESSAGE("Received NOTIFY_GET_TXPOOL_COMPLEMENT (" << arg.hashes.size() << " txes)");
if(context.m_state != cryptonote_connection_context::state_normal)
return 1;

std::vector<std::pair<cryptonote::blobdata, block>> local_blocks;
std::vector<cryptonote::blobdata> local_txs;
Expand Down Expand Up @@ -987,6 +995,12 @@ namespace cryptonote
template<class t_core>
int t_cryptonote_protocol_handler<t_core>::handle_request_get_objects(int command, NOTIFY_REQUEST_GET_OBJECTS::request& arg, cryptonote_connection_context& context)
{
if (context.m_state == cryptonote_connection_context::state_before_handshake)
{
LOG_ERROR_CCONTEXT("Requested objects before handshake, dropping connection");
drop_connection(context, false, false);
return 1;
}
MLOG_P2P_MESSAGE("Received NOTIFY_REQUEST_GET_OBJECTS (" << arg.blocks.size() << " blocks)");
if (arg.blocks.size() > CURRENCY_PROTOCOL_MAX_OBJECT_REQUEST_COUNT)
{
Expand Down Expand Up @@ -1717,6 +1731,12 @@ skip:
int t_cryptonote_protocol_handler<t_core>::handle_request_chain(int command, NOTIFY_REQUEST_CHAIN::request& arg, cryptonote_connection_context& context)
{
MLOG_P2P_MESSAGE("Received NOTIFY_REQUEST_CHAIN (" << arg.block_ids.size() << " blocks");
if (context.m_state == cryptonote_connection_context::state_before_handshake)
{
LOG_ERROR_CCONTEXT("Requested chain before handshake, dropping connection");
drop_connection(context, false, false);
return 1;
}
NOTIFY_RESPONSE_CHAIN_ENTRY::request r;
if(!m_core.find_blockchain_supplement(arg.block_ids, !arg.prune, r))
{
Expand Down