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Merge #9720: net: fix banning and disallow sending messages before receiving verack

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d943491 qa: add a test to detect leaky p2p messages (Cory Fields)
8650bbb qa: Expose on-connection to mininode listeners (Matt Corallo)
5b5e4f8 qa: mininode learns when a socket connects, not its first action (Matt Corallo)
cbfc5a6 net: require a verack before responding to anything else (Cory Fields)
8502e7a net: parse reject earlier (Cory Fields)
c45b9fb net: correctly ban before the handshake is complete (Cory Fields)
This commit is contained in:
Wladimir J. van der Laan 2017-02-14 14:37:14 +01:00
commit e87ce95fbd
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GPG key ID: 74810B012346C9A6
3 changed files with 214 additions and 49 deletions
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1
qa/pull-tester/rpc-tests.py
View file

@ -154,6 +154,7 @@ testScripts = [
'bumpfee.py',
'rpcnamedargs.py',
'listsinceblock.py',
'p2p-leaktests.py',
]
if ENABLE_ZMQ:
testScripts.append('zmq_test.py')

145
qa/rpc-tests/p2p-leaktests.py Executable file
View file

@ -0,0 +1,145 @@
#!/usr/bin/env python3
# Copyright (c) 2017 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
from test_framework.mininode import *
from test_framework.test_framework import BitcoinTestFramework
from test_framework.util import *
'''
Test for message sending before handshake completion
A node should never send anything other than VERSION/VERACK/REJECT until it's
received a VERACK.
This test connects to a node and sends it a few messages, trying to intice it
into sending us something it shouldn't.
'''
banscore = 10
class CLazyNode(NodeConnCB):
def __init__(self):
self.connection = None
self.unexpected_msg = False
self.connected = False
super().__init__()
def add_connection(self, conn):
self.connection = conn
def send_message(self, message):
self.connection.send_message(message)
def bad_message(self, message):
self.unexpected_msg = True
print("should not have received message: %s" % message.command)
def on_open(self, conn):
self.connected = True
def on_version(self, conn, message): self.bad_message(message)
def on_verack(self, conn, message): self.bad_message(message)
def on_reject(self, conn, message): self.bad_message(message)
def on_inv(self, conn, message): self.bad_message(message)
def on_addr(self, conn, message): self.bad_message(message)
def on_alert(self, conn, message): self.bad_message(message)
def on_getdata(self, conn, message): self.bad_message(message)
def on_getblocks(self, conn, message): self.bad_message(message)
def on_tx(self, conn, message): self.bad_message(message)
def on_block(self, conn, message): self.bad_message(message)
def on_getaddr(self, conn, message): self.bad_message(message)
def on_headers(self, conn, message): self.bad_message(message)
def on_getheaders(self, conn, message): self.bad_message(message)
def on_ping(self, conn, message): self.bad_message(message)
def on_mempool(self, conn): self.bad_message(message)
def on_pong(self, conn, message): self.bad_message(message)
def on_feefilter(self, conn, message): self.bad_message(message)
def on_sendheaders(self, conn, message): self.bad_message(message)
def on_sendcmpct(self, conn, message): self.bad_message(message)
def on_cmpctblock(self, conn, message): self.bad_message(message)
def on_getblocktxn(self, conn, message): self.bad_message(message)
def on_blocktxn(self, conn, message): self.bad_message(message)
# Node that never sends a version. We'll use this to send a bunch of messages
# anyway, and eventually get disconnected.
class CNodeNoVersionBan(CLazyNode):
def __init__(self):
super().__init__()
# send a bunch of veracks without sending a message. This should get us disconnected.
# NOTE: implementation-specific check here. Remove if bitcoind ban behavior changes
def on_open(self, conn):
super().on_open(conn)
for i in range(banscore):
self.send_message(msg_verack())
def on_reject(self, conn, message): pass
# Node that never sends a version. This one just sits idle and hopes to receive
# any message (it shouldn't!)
class CNodeNoVersionIdle(CLazyNode):
def __init__(self):
super().__init__()
# Node that sends a version but not a verack.
class CNodeNoVerackIdle(CLazyNode):
def __init__(self):
self.version_received = False
super().__init__()
def on_reject(self, conn, message): pass
def on_verack(self, conn, message): pass
# When version is received, don't reply with a verack. Instead, see if the
# node will give us a message that it shouldn't. This is not an exhaustive
# list!
def on_version(self, conn, message):
self.version_received = True
conn.send_message(msg_ping())
conn.send_message(msg_getaddr())
class P2PLeakTest(BitcoinTestFramework):
def __init__(self):
super().__init__()
self.num_nodes = 1
def setup_network(self):
extra_args = [['-debug', '-banscore='+str(banscore)]
for i in range(self.num_nodes)]
self.nodes = start_nodes(self.num_nodes, self.options.tmpdir, extra_args)
def run_test(self):
no_version_bannode = CNodeNoVersionBan()
no_version_idlenode = CNodeNoVersionIdle()
no_verack_idlenode = CNodeNoVerackIdle()
connections = []
connections.append(NodeConn('127.0.0.1', p2p_port(0), self.nodes[0], no_version_bannode, send_version=False))
connections.append(NodeConn('127.0.0.1', p2p_port(0), self.nodes[0], no_version_idlenode, send_version=False))
connections.append(NodeConn('127.0.0.1', p2p_port(0), self.nodes[0], no_verack_idlenode))
no_version_bannode.add_connection(connections[0])
no_version_idlenode.add_connection(connections[1])
no_verack_idlenode.add_connection(connections[2])
NetworkThread().start() # Start up network handling in another thread
assert(wait_until(lambda: no_version_bannode.connected and no_version_idlenode.connected and no_verack_idlenode.version_received, timeout=10))
# Mine a block and make sure that it's not sent to the connected nodes
self.nodes[0].generate(1)
#Give the node enough time to possibly leak out a message
time.sleep(5)
#This node should have been banned
assert(no_version_bannode.connection.state == "closed")
[conn.disconnect_node() for conn in connections]
# Make sure no unexpected messages came in
assert(no_version_bannode.unexpected_msg == False)
assert(no_version_idlenode.unexpected_msg == False)
assert(no_verack_idlenode.unexpected_msg == False)
if __name__ == '__main__':
P2PLeakTest().main()

117
src/net_processing.cpp
View file

@ -1190,8 +1190,31 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
}
}
if (strCommand == NetMsgType::REJECT)
{
if (fDebug) {
try {
std::string strMsg; unsigned char ccode; std::string strReason;
vRecv >> LIMITED_STRING(strMsg, CMessageHeader::COMMAND_SIZE) >> ccode >> LIMITED_STRING(strReason, MAX_REJECT_MESSAGE_LENGTH);
if (strCommand == NetMsgType::VERSION)
std::ostringstream ss;
ss << strMsg << " code " << itostr(ccode) << ": " << strReason;
if (strMsg == NetMsgType::BLOCK || strMsg == NetMsgType::TX)
{
uint256 hash;
vRecv >> hash;
ss << ": hash " << hash.ToString();
}
LogPrint("net", "Reject %s\n", SanitizeString(ss.str()));
} catch (const std::ios_base::failure&) {
// Avoid feedback loops by preventing reject messages from triggering a new reject message.
LogPrint("net", "Unparseable reject message received\n");
}
}
}
else if (strCommand == NetMsgType::VERSION)
{
// Each connection can only send one version message
if (pfrom->nVersion != 0)
@ -1402,6 +1425,13 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
pfrom->fSuccessfullyConnected = true;
}
else if (!pfrom->fSuccessfullyConnected)
{
// Must have a verack message before anything else
LOCK(cs_main);
Misbehaving(pfrom->GetId(), 1);
return false;
}
else if (strCommand == NetMsgType::ADDR)
{
@ -2549,31 +2579,6 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
pfrom->fRelayTxes = true;
}
else if (strCommand == NetMsgType::REJECT)
{
if (fDebug) {
try {
std::string strMsg; unsigned char ccode; std::string strReason;
vRecv >> LIMITED_STRING(strMsg, CMessageHeader::COMMAND_SIZE) >> ccode >> LIMITED_STRING(strReason, MAX_REJECT_MESSAGE_LENGTH);
std::ostringstream ss;
ss << strMsg << " code " << itostr(ccode) << ": " << strReason;
if (strMsg == NetMsgType::BLOCK || strMsg == NetMsgType::TX)
{
uint256 hash;
vRecv >> hash;
ss << ": hash " << hash.ToString();
}
LogPrint("net", "Reject %s\n", SanitizeString(ss.str()));
} catch (const std::ios_base::failure&) {
// Avoid feedback loops by preventing reject messages from triggering a new reject message.
LogPrint("net", "Unparseable reject message received\n");
}
}
}
else if (strCommand == NetMsgType::FEEFILTER) {
CAmount newFeeFilter = 0;
vRecv >> newFeeFilter;
@ -2601,6 +2606,36 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
return true;
}
static bool SendRejectsAndCheckIfBanned(CNode* pnode, CConnman& connman)
{
AssertLockHeld(cs_main);
CNodeState &state = *State(pnode->GetId());
BOOST_FOREACH(const CBlockReject& reject, state.rejects) {
connman.PushMessage(pnode, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::REJECT, (std::string)NetMsgType::BLOCK, reject.chRejectCode, reject.strRejectReason, reject.hashBlock));
}
state.rejects.clear();
if (state.fShouldBan) {
state.fShouldBan = false;
if (pnode->fWhitelisted)
LogPrintf("Warning: not punishing whitelisted peer %s!\n", pnode->addr.ToString());
else if (pnode->fAddnode)
LogPrintf("Warning: not punishing addnoded peer %s!\n", pnode->addr.ToString());
else {
pnode->fDisconnect = true;
if (pnode->addr.IsLocal())
LogPrintf("Warning: not banning local peer %s!\n", pnode->addr.ToString());
else
{
connman.Ban(pnode->addr, BanReasonNodeMisbehaving);
}
}
return true;
}
return false;
}
bool ProcessMessages(CNode* pfrom, CConnman& connman, const std::atomic<bool>& interruptMsgProc)
{
const CChainParams& chainparams = Params();
@ -2711,8 +2746,12 @@ bool ProcessMessages(CNode* pfrom, CConnman& connman, const std::atomic<bool>& i
PrintExceptionContinue(NULL, "ProcessMessages()");
}
if (!fRet)
if (!fRet) {
LogPrintf("%s(%s, %u bytes) FAILED peer=%d\n", __func__, SanitizeString(strCommand), nMessageSize, pfrom->id);
}
LOCK(cs_main);
SendRejectsAndCheckIfBanned(pfrom, connman);
return fMoreWork;
}
@ -2778,30 +2817,10 @@ bool SendMessages(CNode* pto, CConnman& connman, const std::atomic<bool>& interr
if (!lockMain)
return true;
if (SendRejectsAndCheckIfBanned(pto, connman))
return true;
CNodeState &state = *State(pto->GetId());
BOOST_FOREACH(const CBlockReject& reject, state.rejects)
connman.PushMessage(pto, msgMaker.Make(NetMsgType::REJECT, (std::string)NetMsgType::BLOCK, reject.chRejectCode, reject.strRejectReason, reject.hashBlock));
state.rejects.clear();
if (state.fShouldBan) {
state.fShouldBan = false;
if (pto->fWhitelisted)
LogPrintf("Warning: not punishing whitelisted peer %s!\n", pto->addr.ToString());
else if (pto->fAddnode)
LogPrintf("Warning: not punishing addnoded peer %s!\n", pto->addr.ToString());
else {
pto->fDisconnect = true;
if (pto->addr.IsLocal())
LogPrintf("Warning: not banning local peer %s!\n", pto->addr.ToString());
else
{
connman.Ban(pto->addr, BanReasonNodeMisbehaving);
}
return true;
}
}
// Address refresh broadcast
int64_t nNow = GetTimeMicros();
if (!IsInitialBlockDownload() && pto->nNextLocalAddrSend < nNow) {