Add block gas limit verification

Signed-off-by: Jakub Sztandera <kubuxu@protocol.ai>

chain/sync.go

@@ -950,15 +950,24 @@ func (syncer *Syncer) checkBlockMessages(ctx context.Context, b *types.FullBlock
 		return xerrors.Errorf("failed to load base state tree: %w", err)
 	}
 
+	pl := vm.PricelistByEpoch(baseTs.Height())
+	var sumGasLimit int64
 	checkMsg := func(msg types.ChainMsg) error {
 		m := msg.VMMessage()
 
 		// Phase 1: syntactic validation, as defined in the spec
-		minGas := vm.PricelistByEpoch(baseTs.Height()).OnChainMessage(msg.ChainLength())
+		minGas := pl.OnChainMessage(msg.ChainLength())
 		if err := m.ValidForBlockInclusion(minGas.Total()); err != nil {
 			return err
 		}
 
+		// ValidForBlockInclusion checks if any single message does not exceed BlockGasLimit
+		// So below is overflow safe
+		sumGasLimit += m.GasLimit
+		if sumGasLimit > build.BlockGasLimit {
+			return xerrors.Errorf("block gas limit exceeded")
+		}
+
 		// Phase 2: (Partial) semantic validation:
 		// the sender exists and is an account actor, and the nonces make sense
 		if _, ok := nonces[m.From]; !ok {