Add aggressive restrictions to pre-handshake p2p buffer limit

This commit is contained in:
Lee Clagett 2020-12-29 19:58:53 -05:00
parent a1eca8ca7e
commit 61b6e4cc67
10 changed files with 40 additions and 11 deletions

View file

@ -72,7 +72,8 @@ namespace levin
#define LEVIN_DEFAULT_TIMEOUT_PRECONFIGURED 0
#define LEVIN_DEFAULT_MAX_PACKET_SIZE 100000000 //100MB by default
#define LEVIN_INITIAL_MAX_PACKET_SIZE 256*1024 // 256 KiB before handshake
#define LEVIN_DEFAULT_MAX_PACKET_SIZE 100000000 //100MB by default after handshake
#define LEVIN_PACKET_REQUEST 0x00000001
#define LEVIN_PACKET_RESPONSE 0x00000002

View file

@ -84,7 +84,8 @@ class async_protocol_handler_config
public:
typedef t_connection_context connection_context;
uint64_t m_max_packet_size;
uint64_t m_initial_max_packet_size;
uint64_t m_max_packet_size;
uint64_t m_invoke_timeout;
int invoke(int command, const epee::span<const uint8_t> in_buff, std::string& buff_out, boost::uuids::uuid connection_id);
@ -105,7 +106,7 @@ public:
size_t get_in_connections_count();
void set_handler(levin_commands_handler<t_connection_context>* handler, void (*destroy)(levin_commands_handler<t_connection_context>*) = NULL);
async_protocol_handler_config():m_pcommands_handler(NULL), m_pcommands_handler_destroy(NULL), m_max_packet_size(LEVIN_DEFAULT_MAX_PACKET_SIZE), m_invoke_timeout(LEVIN_DEFAULT_TIMEOUT_PRECONFIGURED)
async_protocol_handler_config():m_pcommands_handler(NULL), m_pcommands_handler_destroy(NULL), m_initial_max_packet_size(LEVIN_INITIAL_MAX_PACKET_SIZE), m_max_packet_size(LEVIN_DEFAULT_MAX_PACKET_SIZE), m_invoke_timeout(LEVIN_DEFAULT_TIMEOUT_PRECONFIGURED)
{}
~async_protocol_handler_config() { set_handler(NULL, NULL); }
void del_out_connections(size_t count);
@ -162,6 +163,7 @@ public:
net_utils::i_service_endpoint* m_pservice_endpoint;
config_type& m_config;
t_connection_context& m_connection_context;
std::atomic<uint64_t> m_max_packet_size;
net_utils::buffer m_cache_in_buffer;
stream_state m_state;
@ -289,7 +291,8 @@ public:
m_current_head(bucket_head2()),
m_pservice_endpoint(psnd_hndlr),
m_config(config),
m_connection_context(conn_context),
m_connection_context(conn_context),
m_max_packet_size(config.m_initial_max_packet_size),
m_cache_in_buffer(4 * 1024),
m_state(stream_state_head)
{
@ -399,13 +402,14 @@ public:
}
// these should never fail, but do runtime check for safety
CHECK_AND_ASSERT_MES(m_config.m_max_packet_size >= m_cache_in_buffer.size(), false, "Bad m_cache_in_buffer.size()");
CHECK_AND_ASSERT_MES(m_config.m_max_packet_size - m_cache_in_buffer.size() >= m_fragment_buffer.size(), false, "Bad m_cache_in_buffer.size() + m_fragment_buffer.size()");
const uint64_t max_packet_size = m_max_packet_size;
CHECK_AND_ASSERT_MES(max_packet_size >= m_cache_in_buffer.size(), false, "Bad m_cache_in_buffer.size()");
CHECK_AND_ASSERT_MES(max_packet_size - m_cache_in_buffer.size() >= m_fragment_buffer.size(), false, "Bad m_cache_in_buffer.size() + m_fragment_buffer.size()");
// flipped to subtraction; prevent overflow since m_max_packet_size is variable and public
if(cb > m_config.m_max_packet_size - m_cache_in_buffer.size() - m_fragment_buffer.size())
if(cb > max_packet_size - m_cache_in_buffer.size() - m_fragment_buffer.size())
{
MWARNING(m_connection_context << "Maximum packet size exceed!, m_max_packet_size = " << m_config.m_max_packet_size
MWARNING(m_connection_context << "Maximum packet size exceed!, m_max_packet_size = " << max_packet_size
<< ", packet received " << m_cache_in_buffer.size() + cb
<< ", connection will be closed.");
return false;
@ -519,6 +523,10 @@ public:
m_current_head.m_command, buff_to_invoke, return_buff, m_connection_context
);
// peer_id remains unset if dropped
if (m_current_head.m_command == m_connection_context.handshake_command() && m_connection_context.handshake_complete())
m_max_packet_size = m_config.m_max_packet_size;
bucket_head2 head = make_header(m_current_head.m_command, return_buff.size(), LEVIN_PACKET_RESPONSE, false);
head.m_return_code = SWAP32LE(return_code);
@ -576,9 +584,9 @@ public:
m_cache_in_buffer.erase(sizeof(bucket_head2));
m_state = stream_state_body;
m_oponent_protocol_ver = m_current_head.m_protocol_version;
if(m_current_head.m_cb > m_config.m_max_packet_size)
if(m_current_head.m_cb > max_packet_size)
{
LOG_ERROR_CC(m_connection_context, "Maximum packet size exceed!, m_max_packet_size = " << m_config.m_max_packet_size
LOG_ERROR_CC(m_connection_context, "Maximum packet size exceed!, m_max_packet_size = " << max_packet_size
<< ", packet header received " << m_current_head.m_cb
<< ", connection will be closed.");
return false;
@ -633,6 +641,9 @@ public:
boost::interprocess::ipcdetail::atomic_write32(&m_invoke_buf_ready, 0);
CRITICAL_REGION_BEGIN(m_invoke_response_handlers_lock);
if (command == m_connection_context.handshake_command())
m_max_packet_size = m_config.m_max_packet_size;
if(!send_message(command, in_buff, LEVIN_PACKET_REQUEST, true))
{
LOG_ERROR_CC(m_connection_context, "Failed to do_send");
@ -674,6 +685,9 @@ public:
boost::interprocess::ipcdetail::atomic_write32(&m_invoke_buf_ready, 0);
if (command == m_connection_context.handshake_command())
m_max_packet_size = m_config.m_max_packet_size;
if (!send_message(command, in_buff, LEVIN_PACKET_REQUEST, true))
{
LOG_ERROR_CC(m_connection_context, "Failed to send request");

View file

@ -55,6 +55,8 @@ namespace cryptonote
state_normal
};
bool handshake_complete() const noexcept { return m_state != state_before_handshake; }
state m_state;
std::vector<std::pair<crypto::hash, uint64_t>> m_needed_objects;
std::unordered_set<crypto::hash> m_requested_objects;

View file

@ -2634,6 +2634,7 @@ skip:
std::vector<std::pair<epee::net_utils::zone, boost::uuids::uuid>> fullConnections, fluffyConnections;
m_p2p->for_each_connection([this, &exclude_context, &fullConnections, &fluffyConnections](connection_context& context, nodetool::peerid_type peer_id, uint32_t support_flags)
{
// peer_id also filters out connections before handshake
if (peer_id && exclude_context.m_connection_id != context.m_connection_id && context.m_remote_address.get_zone() == epee::net_utils::zone::public_)
{
if(m_core.fluffy_blocks_enabled() && (support_flags & P2P_SUPPORT_FLAG_FLUFFY_BLOCKS))

View file

@ -443,7 +443,7 @@ namespace levin
zone->p2p->foreach_connection([txs, now, &zone, &source, &in_duration, &out_duration, &next_flush] (detail::p2p_context& context)
{
// When i2p/tor, only fluff to outbound connections
if (source != context.m_connection_id && (zone->nzone == epee::net_utils::zone::public_ || !context.m_is_income))
if (context.handshake_complete() && source != context.m_connection_id && (zone->nzone == epee::net_utils::zone::public_ || !context.m_is_income))
{
if (context.fluff_txs.empty())
context.flush_time = now + (context.m_is_income ? in_duration() : out_duration());

View file

@ -118,6 +118,8 @@ namespace nodetool
m_in_timedsync(false)
{}
static constexpr int handshake_command() noexcept { return 1001; }
std::vector<cryptonote::blobdata> fluff_txs;
std::chrono::steady_clock::time_point flush_time;
peerid_type peer_id;
@ -139,6 +141,7 @@ namespace nodetool
typedef COMMAND_HANDSHAKE_T<typename t_payload_net_handler::payload_type> COMMAND_HANDSHAKE;
typedef COMMAND_TIMED_SYNC_T<typename t_payload_net_handler::payload_type> COMMAND_TIMED_SYNC;
static_assert(p2p_connection_context::handshake_command() == COMMAND_HANDSHAKE::ID, "invalid handshake command id");
typedef epee::net_utils::boosted_tcp_server<epee::levin::async_protocol_handler<p2p_connection_context>> net_server;

View file

@ -52,6 +52,8 @@ namespace
struct test_levin_connection_context : public epee::net_utils::connection_context_base
{
static constexpr int handshake_command() noexcept { return 1001; }
static constexpr bool handshake_complete() noexcept { return true; }
};
typedef epee::levin::async_protocol_handler_config<test_levin_connection_context> test_levin_protocol_handler_config;

View file

@ -48,6 +48,8 @@ namespace net_load_tests
struct test_connection_context : epee::net_utils::connection_context_base
{
test_connection_context(): epee::net_utils::connection_context_base(boost::uuids::nil_uuid(), {}, false, false), m_closed(false) {}
static constexpr int handshake_command() noexcept { return 1001; }
static constexpr bool handshake_complete() noexcept { return true; }
volatile bool m_closed;
};

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@ -43,6 +43,8 @@ namespace
{
struct test_levin_connection_context : public epee::net_utils::connection_context_base
{
static constexpr int handshake_command() noexcept { return 1001; }
static constexpr bool handshake_complete() noexcept { return true; }
};
typedef epee::levin::async_protocol_handler_config<test_levin_connection_context> test_levin_protocol_handler_config;
@ -193,6 +195,7 @@ namespace
{
m_handler_config.set_handler(m_pcommands_handler, [](epee::levin::levin_commands_handler<test_levin_connection_context> *handler) { delete handler; });
m_handler_config.m_invoke_timeout = invoke_timeout;
m_handler_config.m_initial_max_packet_size = max_packet_size;
m_handler_config.m_max_packet_size = max_packet_size;
}

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@ -178,6 +178,7 @@ namespace
{
using base_type = epee::net_utils::connection_context_base;
static_cast<base_type&>(context_) = base_type{random_generator(), {}, is_incoming, false};
context_.m_state = cryptonote::cryptonote_connection_context::state_normal;
handler_.after_init_connection();
}