Storage Proofs

Summary

The contract processes RLP-encoded proofs in _extractPeriodFromProof, and there is no limit on the size or complexity of the proof data. An attacker could submit a large, complex proof that exceeds the block gas limit, causing the transaction to revert and preventing legitimate updates.

Vulnerability Details

• Description:
  The _extractPeriodFromProof function parses an RLP-encoded proof:

While the function checks that the proof contains exactly 2 items, it does not restrict the size or complexity of the RLP data (e.g., deeply nested structures). The RLPReader and StateProofVerifier libraries process this data, and large inputs can consume excessive gas, potentially exceeding the Ethereum block gas limit (approximately 30 million gas as of March 2025).

• Root Cause: Lack of an upper bound on the size of the _proof_rlp input, allowing arbitrarily large data to be processed.

• Validation: Confirmed by:
  Reviewing the RLPReader library, which recursively processes RLP items, with gas costs proportional to the data size and complexity.
  Analyzing StateProofVerifier.extractSlotValueFromProof, which verifies Merkle proofs, with gas costs increasing with proof length.
  Recognizing that Ethereum’s block gas limit imposes a hard constraint, and unbounded inputs are a known DoS vector.

Impact

• Severity:
  Medium

• Description:
  Prevents legitimate updates to profit_max_unlock_time, potentially delaying oracle adjustments and affecting downstream systems. No direct financial loss occurs, but operational disruption could impact user trust and system reliability.
  Likelihood: Medium, as crafting a large proof requires some effort but is feasible for a motivated attacker with access to the public functions.

Tools Used

Manual Code Review: Analyzed proof parsing logic and gas consumption multiple times.

Recommendations

Proof Size Limit: Add a maximum size check for _proof_rlp in both verifyPeriodByBlockHash and verifyPeriodByStateRoot: