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Merge #11580: Do not send (potentially) invalid headers in response to getheaders

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725b79a [test] Verify node doesn't send headers that haven't been fully validated (Russell Yanofsky)
3788a84 Do not send (potentially) invalid headers in response to getheaders (Matt Corallo)

Pull request description:

  Nowhere else in the protocol do we send headers which are for
  blocks we have not fully validated except in response to getheaders
  messages with a null locator. On my public node I have not seen any
  such request (whether for an invalid block or not) in at least two
  years of debug.log output, indicating that this should have minimal
  impact.

Tree-SHA512: c1f6e0cdcdfb78ea577d555f9b3ceb1b4b60eff4f6cf313bfd8b576c9562d797bea73abc23f7011f249ae36dd539c715f3d20487ac03ace60e84e1b77c0c1e1a
This commit is contained in:
Wladimir J. van der Laan 2017-11-09 19:55:02 +01:00
commit 1f4375f8e7
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GPG key ID: 1E4AED62986CD25D
2 changed files with 43 additions and 13 deletions
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22
src/net_processing.cpp
View file

@ -781,11 +781,13 @@ void Misbehaving(NodeId pnode, int howmuch)
// To prevent fingerprinting attacks, only send blocks/headers outside of the
// active chain if they are no more than a month older (both in time, and in
// best equivalent proof of work) than the best header chain we know about.
static bool StaleBlockRequestAllowed(const CBlockIndex* pindex, const Consensus::Params& consensusParams)
// best equivalent proof of work) than the best header chain we know about and
// we fully-validated them at some point.
static bool BlockRequestAllowed(const CBlockIndex* pindex, const Consensus::Params& consensusParams)
{
AssertLockHeld(cs_main);
return (pindexBestHeader != nullptr) &&
if (chainActive.Contains(pindex)) return true;
return pindex->IsValid(BLOCK_VALID_SCRIPTS) && (pindexBestHeader != nullptr) &&
(pindexBestHeader->GetBlockTime() - pindex->GetBlockTime() < STALE_RELAY_AGE_LIMIT) &&
(GetBlockProofEquivalentTime(*pindexBestHeader, *pindex, *pindexBestHeader, consensusParams) < STALE_RELAY_AGE_LIMIT);
}
@ -1074,14 +1076,9 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
CValidationState dummy;
ActivateBestChain(dummy, Params(), a_recent_block);
}
if (chainActive.Contains(mi->second)) {
send = true;
} else {
send = mi->second->IsValid(BLOCK_VALID_SCRIPTS) &&
StaleBlockRequestAllowed(mi->second, consensusParams);
if (!send) {
LogPrintf("%s: ignoring request from peer=%i for old block that isn't in the main chain\n", __func__, pfrom->GetId());
}
send = BlockRequestAllowed(mi->second, consensusParams);
if (!send) {
LogPrintf("%s: ignoring request from peer=%i for old block that isn't in the main chain\n", __func__, pfrom->GetId());
}
}
// disconnect node in case we have reached the outbound limit for serving historical blocks
@ -2034,8 +2031,7 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
return true;
pindex = (*mi).second;
if (!chainActive.Contains(pindex) &&
!StaleBlockRequestAllowed(pindex, chainparams.GetConsensus())) {
if (!BlockRequestAllowed(pindex, chainparams.GetConsensus())) {
LogPrintf("%s: ignoring request from peer=%i for old block header that isn't in the main chain\n", __func__, pfrom->GetId());
return true;
}

34
test/functional/sendheaders.py
View file

@ -10,6 +10,17 @@ Setup:
receive inv's (omitted from testing description below, this is our control).
Second node is used for creating reorgs.
test_null_locators
==================
Sends two getheaders requests with null locator values. First request's hashstop
value refers to validated block, while second request's hashstop value refers to
a block which hasn't been validated. Verifies only the first request returns
headers.
test_nonnull_locators
=====================
Part 1: No headers announcements before "sendheaders"
a. node mines a block [expect: inv]
send getdata for the block [expect: block]
@ -221,6 +232,29 @@ class SendHeadersTest(BitcoinTestFramework):
inv_node.sync_with_ping()
test_node.sync_with_ping()
self.test_null_locators(test_node)
self.test_nonnull_locators(test_node, inv_node)
def test_null_locators(self, test_node):
tip = self.nodes[0].getblockheader(self.nodes[0].generate(1)[0])
tip_hash = int(tip["hash"], 16)
self.log.info("Verify getheaders with null locator and valid hashstop returns headers.")
test_node.clear_last_announcement()
test_node.get_headers(locator=[], hashstop=tip_hash)
assert_equal(test_node.check_last_announcement(headers=[tip_hash]), True)
self.log.info("Verify getheaders with null locator and invalid hashstop does not return headers.")
block = create_block(int(tip["hash"], 16), create_coinbase(tip["height"] + 1), tip["mediantime"] + 1)
block.solve()
test_node.send_header_for_blocks([block])
test_node.clear_last_announcement()
test_node.get_headers(locator=[], hashstop=int(block.hash, 16))
test_node.sync_with_ping()
assert_equal(test_node.block_announced, False)
test_node.send_message(msg_block(block))
def test_nonnull_locators(self, test_node, inv_node):
tip = int(self.nodes[0].getbestblockhash(), 16)
# PART 1