[magqqgq]

Summary of Changes

Addresses F-01 (Critical) and F-07 (High) from the Starknet Workspace Security Audit in starkgate-contracts:

• Complete u256 Limb Commitment in EIP-712 Signatures (F-01):

  • Updated lock_and_delegate_input_hash in eip712_utils.cairo to hash both amount.low and amount.high.
  • Previously, only amount.low was hashed, allowing an attacker with a signature for amount $X$ to forge a valid delegation transaction for $X + k \cdot 2^{128}$.
  • Updated the EIP-712 type string to LockAndDelegateRequest(delegatee:felt,amount:u256,nonce:felt,expiry:felt) and recomputed LOCK_AND_DELEGATE_TYPE_HASH to 0x34747b0d2887193758ab94a43ee8a024d452a894901af5ca548b220fab47397.

• Verifying Contract Address Binding in Domain Separator (F-07):

  • Included get_contract_address().into() in calc_domain_hash() to bind the EIP-712 domain to the specific deployed contract instance.
  • Prevents cross-contract and cross-chain replay of lock-and-delegate signatures across testnets, forks, or different deployments.
  • Recomputed STARKNET_DOMAIN_TYPE_HASH to 0xca98cfb7dd7f8905a216be4121e5183d688a00106289a1547b8bc15b38461.

• Spender Validation Hardening (F-20):

  • Added assert(spender.is_non_zero(), Errors::ZERO_ADDRESS); in approve_l1_address to prevent zero-address approvals during rescue operations.

• Allowance Saturation:

  • In _increase_account_allowance, saturated the allowance to Bounded::MAX if current_allowance + amount exceeds u256::MAX.

Operational & Deployment Notice

Breaking Change: This update alters both the message and domain hashes. Existing signatures issued under the old scheme will fail validation. Contract redeployment is required because domain_hash is initialized in the constructor and stored immutably in contract storage. Off-chain keepers and front-end signers must be updated in lockstep.

Affected Files

• packages/strk/src/eip712_utils.cairo
• packages/strk/src/erc20_lockable.cairo

Verification

# Verify build and integration tests
scarb --release build
snforge test