Merge pull request #476 from DistributedCollective/fix/staking_stake

Fix/staking stake

contracts/governance/Staking/modules/StakingStakeModule.sol

@@ -41,8 +41,7 @@ contract StakingStakeModule is IFunctionsList, StakingShared, CheckpointsShared,
         uint256 until,
         address stakeFor,
         address delegatee
-    ) external whenNotPaused {
-        _notSameBlockAsStakingCheckpoint(until); // must wait a block before staking again for that same deadline
+    ) external whenNotPaused whenNotFrozen {
         _stake(msg.sender, amount, until, stakeFor, delegatee, false);
     }
 
@@ -128,6 +127,8 @@ contract StakingStakeModule is IFunctionsList, StakingShared, CheckpointsShared,
         if (stakeFor == address(0)) {
             stakeFor = sender;
         }
+        // must wait a block before staking again for that same deadline
+        _notSameBlockAsStakingCheckpoint(until, stakeFor);
 
         /// @dev Delegate for stakeFor if not specified otherwise.
         if (delegatee == address(0)) {
@@ -154,11 +155,12 @@ contract StakingStakeModule is IFunctionsList, StakingShared, CheckpointsShared,
             // @dev only the user that stakes for himself is allowed to delegate VP to another address
             // which works with vesting stakes and prevents vulnerability of delegating VP to an arbitrary address from
             // any address
-            if (delegatee != stakeFor)
+            if (delegatee != stakeFor) {
                 require(
                     stakeFor == sender,
                     "Only stakeFor account is allowed to change delegatee"
                 );
+            }
 
             /// @dev Update delegatee.
             delegates[stakeFor][until] = delegatee;

contracts/governance/Staking/modules/shared/StakingShared.sol

@@ -70,6 +70,7 @@ contract StakingShared is StakingStorageShared, SafeMath96 {
         // abstract
     }
 
+    //SHOULDN'T BE USED, CAN BE EASILY BROKEN USING CONTRACT
     function _notSameBlockAsStakingCheckpoint(uint256 lockDate) internal view {
         uint32 nCheckpoints = numUserStakingCheckpoints[msg.sender][lockDate];
         bool notSameBlock =
@@ -78,6 +79,13 @@ contract StakingShared is StakingStorageShared, SafeMath96 {
         require(notSameBlock, "cannot be mined in the same block as last stake"); // S20
     }
 
+    function _notSameBlockAsStakingCheckpoint(uint256 lockDate, address stakeFor) internal view {
+        uint32 nCheckpoints = numUserStakingCheckpoints[stakeFor][lockDate];
+        bool notSameBlock =
+            userStakingCheckpoints[stakeFor][lockDate][nCheckpoints - 1].fromBlock != block.number;
+        require(notSameBlock, "cannot be mined in the same block as last stake"); // S20
+    }
+
     /**
      * @notice Unstaking is possible every 2 weeks only. This means, to
      * calculate the key value for the staking checkpoints, we need to

contracts/mockup/modules/StakingWrapperMockup.sol

@@ -0,0 +1,30 @@
+pragma solidity ^0.5.17;
+pragma experimental ABIEncoderV2;
+
+import "../../governance/Staking/interfaces/IStaking.sol";
+import "../../interfaces/IERC20.sol";
+
+import "hardhat/console.sol";
+
+contract StakingWrapperMockup {
+    IStaking staking;
+    IERC20 token;
+
+    constructor(IStaking _staking, IERC20 _token) public {
+        staking = _staking;
+        token = _token;
+    }
+
+    function stake2times(
+        uint96 amount,
+        uint256 until,
+        address stakeFor,
+        address delegatee
+    ) external {
+        require(token.transferFrom(msg.sender, address(this), amount * 2));
+        token.approve(address(staking), amount * 2);
+
+        staking.stake(amount, until, stakeFor, delegatee);
+        staking.stake(amount, until, stakeFor, delegatee);
+    }
+}