Ch_301 - M-03 wrong token address on ShortLongSpell.sol

[sherlock-admin]

Ch_301

medium

M-03 wrong token address on ShortLongSpell.sol

Summary

Vulnerability Detail

ShortLongSpell.openPosition() send uToken to SoftVault then deposit it into the Compound protocol to earn a passive yield. In return, SPELL receives share tokes of SoftVault address(strategy.vault)

WERC20.sol should receive address(strategy.vault) token, but the logic of ShortLongSpell.sol subcall (WERC20.sol) wrapper.burn() and pass the uToken address (please check the Code Snippet part) instead of strategy.vault address

Impact

Short/Long Spell will never work

Code Snippet

1- https://github.com/sherlock-audit/2023-04-blueberry/blob/main/blueberry-core/contracts/spell/ShortLongSpell.sol#L128-L141

            address burnToken = address(ISoftVault(strategy.vault).uToken());
            if (collSize > 0) {
                if (posCollToken != address(wrapper))
                    revert Errors.INCORRECT_COLTOKEN(posCollToken);
                bank.takeCollateral(collSize);
                wrapper.burn(burnToken, collSize);
                _doRefund(burnToken);
            }

2- https://github.com/sherlock-audit/2023-04-blueberry/blob/main/blueberry-core/contracts/spell/ShortLongSpell.sol#L229-L234

        // 1. Take out collateral
        bank.takeCollateral(param.amountPosRemove);
        werc20.burn(
            address(ISoftVault(strategy.vault).uToken()),
            param.amountPosRemove
        );

Tool used

Manual Review

Recommendation

1-

-            address burnToken = address(ISoftVault(strategy.vault).uToken());
+            address burnToken = strategy.vault;
            if (collSize > 0) {
                if (posCollToken != address(wrapper))
                    revert Errors.INCORRECT_COLTOKEN(posCollToken);
                bank.takeCollateral(collSize);
                wrapper.burn(burnToken, collSize);
                _doRefund(burnToken);
            }

2-

        // 1. Take out collateral
        bank.takeCollateral(param.amountPosRemove);
        werc20.burn(
-            address(ISoftVault(strategy.vault).uToken()),
+            strategy.vault,
            param.amountPosRemove
        );

[Ch-301]

Escalate for 10 USDC

The same reason as #116 but in a different implementation and it needs another solution

[sherlock-admin]

Escalate for 10 USDC

The same reason as #116 but in a different implementation and it needs another solution

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[hrishibhat]

Escalation accepted

Valid medium
This is a valid issue

[sherlock-admin]

Escalation accepted

Valid medium
This is a valid issue

This issue's escalations have been accepted!

Contestants' payouts and scores will be updated according to the changes made on this issue.

[Gornutz]

Blueberryfi/blueberry-core@f6d1981#diff-608b47c5c74c768d52e4449c12d1a3a9ce5d8ee01cce2e65df2e64996df651cb

[IAm0x52]

Fix looks good. Contract now correctly burns vault rather than vault.uToken