TIP-1036: T2 Hardfork Bug Fixes

Abstract

This meta TIP collects audit-driven bug fixes, security hardening, and correctness updates that activate at T2. Each item is small in isolation, but together they define the complete in-scope T2 bug-fix bundle for this TIP, while fixes already specified by other activated TIPs (such as TIP-1017) are intentionally excluded.

Motivation

Internal and external review uncovered several T2-relevant correctness and security issues across core execution paths. Because these fixes alter state-function behavior at activation boundaries, they need hardfork gating and are grouped here as one coordinated rollout. This meta TIP tracks only fixes that are not already specified by another activated TIP (for example, TIP-1017).

Changes

1. Require tx.origin for AccountKeychain admin ops

PRs: #3202 · Author: @legion2002, #3250 · Author: @0xrusowsky

With T2, authorizeKey, revokeKey, and updateSpendingLimit require direct owner calls by enforcing both transaction_key == Address::ZERO and msg_sender == tx_origin. This blocks indirect contract-call paths from being used to perform key-admin actions with owner-level authority. If tx_origin is not seeded, admin ops are rejected (failed-closed).

2. Reject self-sponsored fee payer signatures

PR: #3200 (merged) · Author: @legion2002

Rejects AA transactions where the fee_payer_signature resolves back to the sender, preventing self-sponsored signatures from bypassing fee-payer assumptions. Enforced in both txpool validation and EVM fee-payer resolution.

3. Check token paused in internal DEX balance swaps

PR: #3204 · Author: @0xrusowsky

Adds a check_not_paused() call in StablecoinDEX internal balance transfers gated behind is_t2(). Previously, swaps using internal DEX balances could bypass the token pause state.

4. Correct built-in policy type data for TIP403Registry

PR: #3203 (merged) · Author: @0xrusowsky

Built-in policies (REJECT_ALL / ALLOW_ALL) are virtual and not stored on-chain. On T2, policyData() now returns the correct PolicyType (WHITELIST / BLACKLIST respectively) and Address::ZERO admin for these built-in IDs instead of falling through to storage reads.

5. Reject legacy invalid policy types in compound sub-policies

PR: #3188 (merged) · Author: @howydev

Uses is_simple() instead of !is_compound() to validate compound policy sub-policies, rejecting legacy type-255 policies that previously passed the negated check.

6. Handle T2 policy errors in DEX

PR: #3015 (merged) · Author: @0xrusowsky

Updates DEX precompiles to handle the new TIP403RegistryError::InvalidPolicyType error returned by policy_type() post-T2, replacing the old Panic(UnderOverflow) sentinel.

7. Return zero remaining limit for revoked keys

PR: #2553 (merged) · Author: @0xrusowsky

getRemainingLimit() now returns zero for revoked or non-existent access keys instead of a stale positive value.

8. Nonce key gas repricing

PR: #2533 (merged) · Author: @0xrusowsky

Increases intrinsic gas costs for 2D nonce keys on T2 by adding 2 × WARM_SLOAD to both existing-key and new-key gas to account for extended storage lookups. Base costs differ (COLD_SLOAD + WARM_SSTORE_RESET for existing, COLD_SLOAD + SSTORE_SET for new), but the T2 delta is the same.

9. Error with PolicyNotFound for non-existent policy IDs

PR: #2618 (merged) · Author: @0xrusowsky

get_policy_data() now reverts with PolicyNotFound for non-existent policy IDs instead of silently returning default values.

10. Refund spending limit for unused gas fees

PR: #2528 (merged) · Author: @legion2002

Restores access key spending limits by the refunded gas amount in transfer_fee_post_tx(). Previously the full max fee was permanently deducted from the spending limit regardless of actual gas used.

11. Tick spacing checks on DEX price conversion functions

PR: #2513 (merged) · Author: @0xKitsune

Adds tick spacing validation to tick_to_price and price_to_tick, rejecting ticks that don't align with the pool's configured spacing.

12. Reserved liquidity transient storage check

PR: #2496 (merged) · Author: @0xKitsune

Adds a transient storage (TSTORE/TLOAD) guard to prevent reserved liquidity from being double-spent within the same transaction.

13. Reject zero-address ecrecover in permit

PR: #2786 (merged) · Author: @howydev

permit() now explicitly rejects recovered == address(0) before comparing against owner. Previously, a crafted signature recovering to address(0) could have been accepted if owner was also address(0).