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Fix logical race in rest_getutxos

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Calling ActiveHeight() and ActiveTip() subsequently without holding the
::cs_main lock over both calls may result in a height that does not
correspond to the tip due to a race.

Fix this by holding the lock.
This commit is contained in:
MacroFake 2022-07-12 18:03:25 +02:00
parent fa97a528d6
commit fac15ff673
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GPG key ID: CE2B75697E69A548
1 changed files with 9 additions and 5 deletions
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14
src/rest.cpp
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@ -784,14 +784,18 @@ static bool rest_getutxos(const std::any& context, HTTPRequest* req, const std::
ChainstateManager* maybe_chainman = GetChainman(context, req); ChainstateManager* maybe_chainman = GetChainman(context, req);
if (!maybe_chainman) return false; if (!maybe_chainman) return false;
ChainstateManager& chainman = *maybe_chainman; ChainstateManager& chainman = *maybe_chainman;
decltype(chainman.ActiveHeight()) active_height;
uint256 active_hash;
{ {
auto process_utxos = [&vOutPoints, &outs, &hits](const CCoinsView& view, const CTxMemPool* mempool) { auto process_utxos = [&vOutPoints, &outs, &hits, &active_height, &active_hash, &chainman](const CCoinsView& view, const CTxMemPool* mempool) EXCLUSIVE_LOCKS_REQUIRED(chainman.GetMutex()) {
for (const COutPoint& vOutPoint : vOutPoints) { for (const COutPoint& vOutPoint : vOutPoints) {
Coin coin; Coin coin;
bool hit = (!mempool || !mempool->isSpent(vOutPoint)) && view.GetCoin(vOutPoint, coin); bool hit = (!mempool || !mempool->isSpent(vOutPoint)) && view.GetCoin(vOutPoint, coin);
hits.push_back(hit); hits.push_back(hit);
if (hit) outs.emplace_back(std::move(coin)); if (hit) outs.emplace_back(std::move(coin));
} }
active_height = chainman.ActiveHeight();
active_hash = chainman.ActiveTip()->GetBlockHash();
}; };
if (fCheckMemPool) { if (fCheckMemPool) {
@ -819,7 +823,7 @@ static bool rest_getutxos(const std::any& context, HTTPRequest* req, const std::
// serialize data // serialize data
// use exact same output as mentioned in Bip64 // use exact same output as mentioned in Bip64
CDataStream ssGetUTXOResponse(SER_NETWORK, PROTOCOL_VERSION); CDataStream ssGetUTXOResponse(SER_NETWORK, PROTOCOL_VERSION);
ssGetUTXOResponse << chainman.ActiveChain().Height() << chainman.ActiveChain().Tip()->GetBlockHash() << bitmap << outs; ssGetUTXOResponse << active_height << active_hash << bitmap << outs;
std::string ssGetUTXOResponseString = ssGetUTXOResponse.str(); std::string ssGetUTXOResponseString = ssGetUTXOResponse.str();
req->WriteHeader("Content-Type", "application/octet-stream"); req->WriteHeader("Content-Type", "application/octet-stream");
@ -829,7 +833,7 @@ static bool rest_getutxos(const std::any& context, HTTPRequest* req, const std::
case RESTResponseFormat::HEX: { case RESTResponseFormat::HEX: {
CDataStream ssGetUTXOResponse(SER_NETWORK, PROTOCOL_VERSION); CDataStream ssGetUTXOResponse(SER_NETWORK, PROTOCOL_VERSION);
ssGetUTXOResponse << chainman.ActiveChain().Height() << chainman.ActiveChain().Tip()->GetBlockHash() << bitmap << outs; ssGetUTXOResponse << active_height << active_hash << bitmap << outs;
std::string strHex = HexStr(ssGetUTXOResponse) + "\n"; std::string strHex = HexStr(ssGetUTXOResponse) + "\n";
req->WriteHeader("Content-Type", "text/plain"); req->WriteHeader("Content-Type", "text/plain");
@ -842,8 +846,8 @@ static bool rest_getutxos(const std::any& context, HTTPRequest* req, const std::
// pack in some essentials // pack in some essentials
// use more or less the same output as mentioned in Bip64 // use more or less the same output as mentioned in Bip64
objGetUTXOResponse.pushKV("chainHeight", chainman.ActiveChain().Height()); objGetUTXOResponse.pushKV("chainHeight", active_height);
objGetUTXOResponse.pushKV("chaintipHash", chainman.ActiveChain().Tip()->GetBlockHash().GetHex()); objGetUTXOResponse.pushKV("chaintipHash", active_hash.GetHex());
objGetUTXOResponse.pushKV("bitmap", bitmapStringRepresentation); objGetUTXOResponse.pushKV("bitmap", bitmapStringRepresentation);
UniValue utxos(UniValue::VARR); UniValue utxos(UniValue::VARR);