TokenController interactions after balance updates #24
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Glad to see we're eliminating this one. If you need help with writing the test let me know. |
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If we need to test it, we need to do a reentrancy call using a crafted TokenController for that purpose. |
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Yes exactly. That's what I'm looking for. I've done this a couple of times, so let me know if you need help! Here's a concrete example of it: https://github.com/0x-r4bbit/simple-reentrancy-attack |
4 tasks
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Added a test case in #26 |
0x-r4bbit
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Sep 20, 2023
If a `MiniMeToken` has a `TokenController` configured, it can intercept every transfer using the `onTransfer` callback and reenter the `MiniMeToken` contract. This is a reentrancy vulnerablity as a malicious `TokenController` has access to the `MiniMeToken` `balances` and it privileged to perform transfers. Unfortunately, simply using the CEI-pattern as done in #24 isn't sufficient, because the reentrancy can be done non-recursively, resulting in no error and a possible double spent issue. To prevent this vulnerablity, this commit introduces OZ's `ReentrancyGuard` and makes `MiniMeToken` inherit it. This gives us access to the `nonReentrant` modifer that is attached to every transfer function. The commit also introduces a test that proves that the contract reverts in case of a reentrancy attempt. Closes: #17
0x-r4bbit
added a commit
that referenced
this pull request
Sep 20, 2023
If a `MiniMeToken` has a `TokenController` configured, it can intercept every transfer using the `onTransfer` callback and reenter the `MiniMeToken` contract. This is a reentrancy vulnerablity as a malicious `TokenController` has access to the `MiniMeToken` `balances` and it privileged to perform transfers. Unfortunately, simply using the CEI-pattern as done in #24 isn't sufficient, because the reentrancy can be done non-recursively, resulting in no error and a possible double spent issue. To prevent this vulnerablity, this commit introduces OZ's `ReentrancyGuard` and makes `MiniMeToken` inherit it. This gives us access to the `nonReentrant` modifer that is attached to every transfer function. The commit also introduces a test that proves that the contract reverts in case of a reentrancy attempt. Closes: #17
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WIP for #17 in top of #29
Description
moved the interaction
!TokenController(controller).onTransfer(_from, _to, _amount)to be called after the update balances happened, so in case of it having a reentrancy, the checks will fail because the balance already changed.Checklist
Ensure you completed all of the steps below before submitting your pull request:
forge snapshot?pnpm lint?forge test?