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fix: resolve signed integer overflow UB in CoinJoin priority and timeout #7236

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Merged
PastaPastaPasta merged 2 commits into from
Mar 26, 2026
Merged

fix: resolve signed integer overflow UB in CoinJoin priority and timeout #7236

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817234f
fix: resolve signed integer overflow UB in CoinJoin priority and timeout
thepastaclaw Mar 18, 2026
e8ec63a
test: add regression tests for CoinJoin UB fixes
thepastaclaw Mar 20, 2026
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1 change: 1 addition & 0 deletions src/coinjoin/coinjoin.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,7 @@ bool CCoinJoinQueue::CheckSignature(const CBLSPublicKey& blsPubKey) const

bool CCoinJoinQueue::IsTimeOutOfBounds(int64_t current_time) const
{
if (current_time < 0 || nTime < 0) return true;
return current_time - nTime > COINJOIN_QUEUE_TIMEOUT ||
nTime - current_time > COINJOIN_QUEUE_TIMEOUT;
}
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1 change: 1 addition & 0 deletions src/coinjoin/common.h
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Expand Up @@ -118,6 +118,7 @@ constexpr bool IsCollateralAmount(CAmount nInputAmount)

constexpr int CalculateAmountPriority(CAmount nInputAmount)
{
if (nInputAmount < 0 || nInputAmount > MAX_MONEY) return 0;
if (auto optDenom = util::find_if_opt(GetStandardDenominations(),
[&nInputAmount](const auto& denom) { return nInputAmount == denom; })) {
return (float)COIN / *optDenom * 10000;
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49 changes: 49 additions & 0 deletions src/test/coinjoin_queue_tests.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -7,9 +7,14 @@
#include <active/masternode.h>
#include <bls/bls.h>
#include <coinjoin/coinjoin.h>
#include <coinjoin/common.h>
#include <consensus/amount.h>

#include <uint256.h>

#include <climits>
#include <cstdint>

#include <boost/test/unit_test.hpp>

BOOST_FIXTURE_TEST_SUITE(coinjoin_queue_tests, TestingSetup)
Expand Down Expand Up @@ -96,4 +101,48 @@ BOOST_AUTO_TEST_CASE(queue_timestamp_validation)
BOOST_CHECK(q.IsTimeOutOfBounds(current_time));
}

BOOST_AUTO_TEST_CASE(queue_timestamp_extreme_values)
{
CCoinJoinQueue q;
q.nDenom = CoinJoin::AmountToDenomination(CoinJoin::GetSmallestDenomination());
q.m_protxHash = uint256::ONE;

// Negative timestamps are rejected by the guard
q.nTime = INT64_MIN;
BOOST_CHECK(q.IsTimeOutOfBounds(INT64_MAX));

q.nTime = INT64_MAX;
BOOST_CHECK(q.IsTimeOutOfBounds(INT64_MIN));

q.nTime = INT64_MIN;
BOOST_CHECK(q.IsTimeOutOfBounds(INT64_MIN));

// Large positive timestamp with same value: zero diff, in bounds
q.nTime = INT64_MAX;
BOOST_CHECK(!q.IsTimeOutOfBounds(INT64_MAX));

// Zero vs extreme positive: huge gap, out of bounds
q.nTime = 0;
BOOST_CHECK(q.IsTimeOutOfBounds(INT64_MAX));

// Zero vs negative: rejected by guard
q.nTime = 0;
BOOST_CHECK(q.IsTimeOutOfBounds(INT64_MIN));
}

static_assert(CoinJoin::CalculateAmountPriority(MAX_MONEY) == -(MAX_MONEY / COIN));
static_assert(CoinJoin::CalculateAmountPriority(static_cast<CAmount>(INT64_MAX)) == 0);
static_assert(CoinJoin::CalculateAmountPriority(static_cast<CAmount>(-1)) == 0);

BOOST_AUTO_TEST_CASE(calculate_amount_priority_guard)
{
// Realistic amount: MAX_MONEY (21 million DASH)
BOOST_CHECK_EQUAL(CoinJoin::CalculateAmountPriority(MAX_MONEY), -(MAX_MONEY / COIN));

// Out-of-range amounts return 0
BOOST_CHECK_EQUAL(CoinJoin::CalculateAmountPriority(static_cast<CAmount>(INT64_MAX)), 0);
BOOST_CHECK_EQUAL(CoinJoin::CalculateAmountPriority(static_cast<CAmount>(-1)), 0);
BOOST_CHECK_EQUAL(CoinJoin::CalculateAmountPriority(MAX_MONEY + 1), 0);
}

BOOST_AUTO_TEST_SUITE_END()
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