Support updated EIP-1271 implementation for signature validation

[akshay-ap]

Context:

Safe contract supports contract signature validation using EIP-1271. The Safe contracts defines an interface which has a function declaration isValidSignature(bytes, bytes) which is used to validating the contract signatures. But, EIP-1271 defines isValidSignature(bytes32,bytes) for validating contract signatures. This PR addresses this issue by removing the use of legacy implementation of EIP-1271.

Fixes: https://github.com/safe-global/safe-contracts/issues/391 Forum discussion: https://forum.safe.global/t/safe-contract-v1-5-0/3383

Motivation

• By complying to updated EIP-1271 standard will allow safe contracts to interact with other contracts and systems that adhere to the latest version of EIP-1271.

Changes proposed in the PR:

• [x] Remove use of isValidSignature(bytes, bytes) in the interface and replace with isValidSignature(bytes32,bytes)
• [x] Deprecate use of data parameter with checking signatures. The checkNSignatures and checkSignatures functions still has the placeholder for this parameter but it is not used anymore.
• [x] Update value of variable EIP1271_MAGIC_VALUE to 0x1626ba7e as per updated EIP-1271 definition.
• [x] Remove variable UPDATED_MAGIC_VALUE from CompatibilityFallbackHandler.sol as not needed anymore.
• [x] Fix failing test cases
• [x] Remove test cases for isValidSignature(bytes, bytes)
• [x] Remove isValidSignature(bytes, bytes) and update isValidSignature(bytes32, bytes) in CompatibilityFallbackHandler.sol. link to diff
• [x] Remove error codeGS027 (Data Hash and hash of the pre-image data do not match) as not needed anymore.

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Pull Request Test Coverage Report for Build 5255903321

• 8 of 8 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.04%) to 97.034%

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Totals
Change from base Build 5024015688:	-0.04%
Covered Lines:	304
Relevant Lines:	312

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💛 - Coveralls

[akshay-ap]

I have read the CLA Document and I hereby sign the CLA

[andyrobert3]

Is there a timeline when this will be merged and release, for which Safe version?

Because in the new EIP1271 version, we would sign on the dataHash (much simpler)

However, in the current Safe EIP1271 implementation, we must follow & implement the EIP712 hashing scheme off-chain, before signing it. Then we pass the original data message, and the final signature after EIP712 hashing scheme

[akshay-ap]

Is there a timeline when this will be merged and release, for which Safe version?

Because in the new EIP1271 version, we would sign on the dataHash (much simpler)

However, in the current Safe EIP1271 implementation, we must follow & implement the EIP712 hashing scheme off-chain, before signing it. Then we pass the original data message, and the final signature after EIP712 hashing scheme

@andyrobert3 This feature will be merged as a part of release v1.5.0. And regarding timeline, after release v1.4.1 we will work on this release.