cmichel - Spec: Wrong description of withdrawal process

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cmichel

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Spec: Wrong description of withdrawal process

Summary

Wrong description of the withdrawal process in the spec.

Vulnerability Detail

The withdrawals.md describes the second step of the withdrawal process as:

2. The OptimismPortal contract retrieves the output root for the given block number from the L2OutputOracle's
   getL2OutputAfter() function, and performs the remainder of the verification process internally.

The getL2OutputAfter call is never performed. This function does not even exist, most likely, it was referring to getL2OutputIndexAfter. However, even this function is not called. What happens in the withdrawal process is that getL2Output is called to retrieve the output root for the given block number (index).

Impact

The withdrawal process should be clearly documented in the spec. Currently, it's referring to a non-existant function.

Code Snippet

https://github.com/ethereum-optimism/optimism/blob/3f4b3c328153a8aa03611158b6984d624b17c1d9/specs/withdrawals.md?plain=1#L67

Tool used

Manual Review

Recommendation

Fix the spec by referring to getL2Output(l2OutputIndex) instead.