Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

ERC-20 transferFrom greater than allowance not allowed #41

Open
wants to merge 3 commits into
base: main
Choose a base branch
from
Open
Show file tree
Hide file tree
Changes from 2 commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions PROPERTIES.md
Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@ This file lists all the currently implemented Echidna property tests for ERC20,
| ERC20-BASE-015 | [test_ERC20_setAllowance](https://github.com/crytic/properties/blob/main/contracts/ERC20/internal/properties/ERC20BasicProperties.sol#L160) | Allowances should be set correctly when `approve` is called. |
| ERC20-BASE-016 | [test_ERC20_setAllowanceTwice](https://github.com/crytic/properties/blob/main/contracts/ERC20/internal/properties/ERC20BasicProperties.sol#L167) | Allowances should be updated correctly when `approve` is called twice. |
| ERC20-BASE-017 | [test_ERC20_spendAllowanceAfterTransfer](https://github.com/crytic/properties/blob/main/contracts/ERC20/internal/properties/ERC20BasicProperties.sol#L178) | After `transferFrom`, allowances should be updated correctly. |
| ERC20-BASE-018 | [test_ERC20_transferFromMoreThanAllowance](https://github.com/crytic/properties/blob/main/contracts/ERC20/internal/properties/ERC20BasicProperties.sol#L294) | `transferFrom`s for more than allowance should not be allowed. |

### Tests for burnable tokens

Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -317,4 +317,30 @@ abstract contract CryticERC20ExternalBasicProperties is
);
}
}

// Transfers for more than allowance should not be allowed
function test_ERC20external_transferFromMoreThanAllowance(
address target
) public {
uint256 balance_sender = token.balanceOf(msg.sender);
uint256 balance_receiver = token.balanceOf(target);
uint256 allowance = token.allowance(msg.sender, address(this));
require(balance_sender > 0 && allowance < balance_sender);

bool r = token.transferFrom(msg.sender, target, allowance + 1);
assertWithMsg(
r == false,
"Successful transferFrom for more than allowance"
);
assertEq(
token.balanceOf(msg.sender),
balance_sender,
"TransferFrom for more than amount approved source allowance"
);
assertEq(
token.balanceOf(target),
balance_receiver,
"TransferFrom for more than amount approved target allowance"
);
}
}
26 changes: 26 additions & 0 deletions contracts/ERC20/internal/properties/ERC20BasicProperties.sol
Original file line number Diff line number Diff line change
Expand Up @@ -289,4 +289,30 @@ abstract contract CryticERC20BasicProperties is CryticERC20Base {
);
}
}

// TransferFrom for more than allowance should not be allowed
function test_ERC20_transferFromMoreThanAllowance(
address target
) public {
uint256 balance_sender = balanceOf(msg.sender);
uint256 balance_receiver = balanceOf(target);
uint256 allowance = allowance(msg.sender, address(this));
require(balance_sender > 0 && allowance < balance_sender);

bool r = this.transferFrom(msg.sender, target, allowance + 1);
assertWithMsg(
r == false,
"Successful transferFrom for more than allowance"
);
assertEq(
balanceOf(msg.sender),
balance_sender,
"TransferFrom for more than amount approved source allowance"
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

i'm not sure if i understand the 4 error messages, if given out of context (like, when the property fails).
something like "TransferFrom for more than approval affected sender/receiver balance" should be clearer, what do you think?

Copy link
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I updated the error messages, let me know if they sound clearer now.

);
assertEq(
balanceOf(target),
balance_receiver,
"TransferFrom for more than amount approved target allowance"
);
}
}