Merge pull request #1243 from mintlayer/fix/checked_ops_uint

Use only checked math ops for Uint* types

Author: TheQuantumPhysicist

chainstate/src/detail/block_invalidation/mod.rs

@@ -175,8 +175,11 @@ impl<'a, S: BlockchainStorage, V: TransactionVerificationStrategy> BlockInvalida
             let cur_best_block_index = get_best_block_index(&chainstate_ref)?;
             let cur_best_chain_trust = cur_best_block_index.chain_trust();
 
-            let best_chain_candidates =
-                BestChainCandidates::new(&chainstate_ref, cur_best_chain_trust + Uint256::ONE)?;
+            let best_chain_candidates = BestChainCandidates::new(
+                &chainstate_ref,
+                (cur_best_chain_trust + Uint256::ONE)
+                    .expect("Chain trust won't be saturated in a very long time"),
+            )?;
 
             (cur_best_chain_trust, best_chain_candidates)
         };

chainstate/src/detail/chainstateref/mod.rs

@@ -974,7 +974,8 @@ impl<'a, S: BlockchainStorageRead, V: TransactionVerificationStrategy> Chainstat
 
         // Set Chain Trust
         let prev_block_chaintrust: Uint256 = prev_block_index.chain_trust();
-        let chain_trust = prev_block_chaintrust + current_block_proof;
+        let chain_trust = (prev_block_chaintrust + current_block_proof)
+            .expect("Chain trust growth is locally controlled. This can't happen.");
         let block_index = BlockIndex::new(
             block,
             chain_trust,

chainstate/tx-verifier/src/transaction_verifier/reward_distribution.rs

@@ -191,7 +191,9 @@ fn calculate_rewards_per_delegation(
         .map(
             |(delegation_id, balance_amount)| -> Result<_, ConnectTransactionError> {
                 let balance = Uint256::from_amount(*balance_amount);
-                let reward = (total_delegations_reward * balance) / total_delegations_balance;
+                let numer = (total_delegations_reward * balance).expect("Source types are smaller");
+                let reward = (numer / total_delegations_balance)
+                    .ok_or(ConnectTransactionError::TotalDelegationBalanceZero(pool_id))?;
                 let reward: common::primitives::amount::UnsignedIntType =
                     reward.try_into().map_err(|_| {
                         ConnectTransactionError::DelegationRewardOverflow(

common/src/chain/block/consensus_data.rs

@@ -145,9 +145,9 @@ impl PoWData {
         let target: Uint256 = self.bits.try_into().ok()?;
         let mut ret = !target;
         let mut ret1 = target;
-        ret1.increment();
-        ret = ret / ret1;
-        ret.increment();
+        ret1 = (ret1 + Uint256::ONE)?;
+        ret = (ret / ret1)?;
+        ret = (ret + Uint256::ONE).unwrap_or(Uint256::MAX);
         Some(ret)
     }
 }

common/src/chain/chaintrust/asymptote.rs

@@ -96,7 +96,9 @@ pub fn calculate_block_proof(timestamp_diff: u64) -> Uint256 {
     let block_weight = Uint256::from(get_weight_for_block());
     let empty_time_slots_weight = Uint256::from(empty_time_slots_weight);
 
-    block_weight - empty_time_slots_weight
+    block_weight
+        .checked_sub(&empty_time_slots_weight)
+        .expect("Checked above; cannot fail")
 }
 
 #[cfg(test)]
@@ -171,7 +173,7 @@ mod tests {
         // Given that the maximum block weight is 1*SCALING_FACTOR,
         // and it only goes down when there are empty time-slots in between,
         // the maximum chain trust is the following:
-        let max_chain_trust = max_block_height * single_block_weight;
+        let max_chain_trust = (max_block_height * single_block_weight).unwrap();
 
         // There should not be any overflow to ensure that the chain trust is always less than the maximum possible value.
         assert!(max_block_height < max_chain_trust);

common/src/chain/pos.rs

@@ -162,7 +162,8 @@ const DEFAULT_MATURITY_DISTANCE: BlockDistance = BlockDistance::new(2000);
 
 pub fn create_testnet_pos_config(consensus_version: PoSConsensusVersion) -> PoSChainConfig {
     let target_block_time = NonZeroU64::new(2 * 60).expect("cannot be 0");
-    let target_limit = Uint256::MAX / Uint256::from_u64(target_block_time.get());
+    let target_limit = (Uint256::MAX / Uint256::from_u64(target_block_time.get()))
+        .expect("Target block time cannot be zero as per NonZeroU64");
 
     PoSChainConfig {
         target_limit,
@@ -189,7 +190,8 @@ pub fn create_unittest_pos_config() -> PoSChainConfig {
 
 pub fn create_regtest_pos_config(consensus_version: PoSConsensusVersion) -> PoSChainConfig {
     let target_block_time = NonZeroU64::new(2 * 60).expect("cannot be 0");
-    let target_limit = Uint256::MAX / Uint256::from_u64(target_block_time.get());
+    let target_limit = (Uint256::MAX / Uint256::from_u64(target_block_time.get()))
+        .expect("Target block time cannot be zero as per NonZeroU64");
 
     PoSChainConfig {
         target_limit,

common/src/chain/pow.rs

@@ -189,8 +189,9 @@ mod tests {
                 0xFFFFFFFFFFFFFFFF,
             ]);
 
-            let target_max =
-                target_max / Uint256::from_u64(mainnet_cfg.target_timespan().as_secs() * 4);
+            let target_max = (target_max
+                / Uint256::from_u64(mainnet_cfg.target_timespan().as_secs() * 4))
+            .unwrap();
             assert!(mainnet_cfg.limit() < target_max);
         }
     }