[EP 6.35] [Executable] Replace DNSSEC oracle algorithms

Abstract

This proposal replaces three DNSSEC oracle algorithms with newly deployed contracts to address the following two issues:

• feat: Replace EllipticCurve with EIP-7951 P-256 precompile for Algorithm 13
• RSA Signature Forgery via Missing PKCS#1 v1.5 Padding Validation in ENS DNSSEC Oracle

Motivation

RSA Signature Forgery (Critical)

The RSASHA256Algorithm and RSASHA1Algorithm contracts fail to validate PKCS#1 v1.5 padding structure when verifying RSA signatures. The contracts only check whether the last 32 (or 20) bytes of the decrypted signature match the expected hash, ignoring the required padding format defined in RFC 3447. This enables Bleichenbacher's 2006 signature forgery attack against DNS zones using RSA keys with low public exponents (e=3).

Two ENS-supported TLDs — .cc and .name — use e=3 for their Key Signing Keys, allowing any domain under these TLDs to be fraudulently claimed on ENS without DNS ownership. The attack is permissionless, costs approximately 100k gas, and is difficult to detect as the forged proofs appear legitimate. Remediation requires governance intervention.

This vulnerability class has resulted in critical CVEs in other systems (CVE-2006-4339 in OpenSSL, CVE-2014-1568 in NSS, CVE-2016-1494 in python-rsa).

P-256 Precompile Upgrade (Gas Optimization)

The current P256SHA256Algorithm contract uses a Solidity-based EllipticCurve library for signature verification, consuming approximately 200,000+ gas per operation. EIP-7951 introduces a native P-256 precompile (at address 0x100) which reduces this to approximately 3,500 gas — a ~98% reduction. This upgrade takes advantage of the precompile available after the Fusaka hardfork.

Specification

Description

And newly deployed contract information is as follows

• RSASHA1_ADDRESS = 0x58E0383E21f25DaB957F6664240445A514E9f5e8
• RSASHA256_ADDRESS = 0xaee0E2c4d5AB2fc164C8b0Cc8D3118C1c752C95E
• P256SHA256_ADDRESS = 0xB091C4F6FAc16eDDA5Ee1E0f4738f80011905878

Steps overview are as follows

• 1-3. DNSSECImpl: setAlgorithm of RSASHA1, RSASHA256 (RSA Signature Forgery patch), P256SHA256 (Using p-256 precompile) to newly deployed contracts
• 4-5. Root: setSubnodeOwner of cc and name to 0
• 6-7: DNSRegistrar: Call enableNode for .cc and .name to re-enable them for DNSSEC.

DNSSEC_IMPL_ADDRESS = 0x0fc3152971714E5ed7723FAFa650F86A4BaF30C5 ROOT_ADDRESS = 0xaB528d626EC275E3faD363fF1393A41F581c5897 DNS_REGISTRAR_ADDRESS = 0xB32cB5677a7C971689228EC835800432B339bA2B

Transactions Summary

This proposal contains 7 transaction(s) to be executed by the ENS DAO Timelock.

Detailed Transaction Information

Transaction 1: Set Algorithm of RSASHA1 to new address

Target: DNSSECImpl

Address: 0x0fc3152971714E5ed7723FAFa650F86A4BaF30C5

Function: setAlgorithm

• id : 5
• algo: 0x58E0383E21f25DaB957F6664240445A514E9f5e8

0x020ed8d3000000000000000000000000000000000000000000000000000000000000000500000000000000000000000058e0383e21f25dab957f6664240445a514e9f5e8

Transaction 2: Set Algorithm of RSASHA256 to new address

Target: DNSSECImpl

Address: 0x0fc3152971714E5ed7723FAFa650F86A4BaF30C5

Function: setAlgorithm

• id : 8
• algo: 0xaee0E2c4d5AB2fc164C8b0Cc8D3118C1c752C95E

0x020ed8d30000000000000000000000000000000000000000000000000000000000000008000000000000000000000000aee0e2c4d5ab2fc164c8b0cc8d3118c1c752c95e

Transaction 3: Set Algorithm of P256SHA256 to new address

Target: DNSSECImpl

Address: 0x0fc3152971714E5ed7723FAFa650F86A4BaF30C5

Function: setAlgorithm

• id : 13
• algo: 0xB091C4F6FAc16eDDA5Ee1E0f4738f80011905878

0x020ed8d3000000000000000000000000000000000000000000000000000000000000000d000000000000000000000000b091c4f6fac16edda5ee1e0f4738f80011905878

Transaction 4: setSubnodeOwner of cc to 0

Target: Root

Address: 0xaB528d626EC275E3faD363fF1393A41F581c5897

Function: setSubnodeOwner

• label : 0x68ce0763ca729318b714b0cf33478e4e228e19f58aeaf12cfa1535c9d4bbcaf9
• owner: 0x0000000000000000000000000000000000000000

0x8cb8ecec68ce0763ca729318b714b0cf33478e4e228e19f58aeaf12cfa1535c9d4bbcaf90000000000000000000000000000000000000000000000000000000000000000

Transaction 5: setSubnodeOwner of name back to DNS_REGISTRAR_ADDRESS

Target: Root

Address: 0xaB528d626EC275E3faD363fF1393A41F581c5897

Function: setSubnodeOwner

• label : 0x2361458367e696363fbcc70777d07ebbd2394e89fd0adcaf147faccd1d294d60
• owner: 0x0000000000000000000000000000000000000000

0x8cb8ecec2361458367e696363fbcc70777d07ebbd2394e89fd0adcaf147faccd1d294d600000000000000000000000000000000000000000000000000000000000000000

Transaction 6: Re-enable cc for DNSSEC

Target: DNSRegistrar

Address: 0xB32cB5677a7C971689228EC835800432B339bA2B

Function: enableNode

• domain : 0x02636300

0x6f951221000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000040263630000000000000000000000000000000000000000000000000000000000

Transaction 7: Re-enable name for DNSSEC

Target: DNSRegistrar

Address: 0xB32cB5677a7C971689228EC835800432B339bA2B

Function: enableNode

• domain : 0x046e616d6500

0x6f95122100000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000006046e616d65000000000000000000000000000000000000000000000000000000