System.checkAuthority using getContractMetadata

[joticajulian]

Brief description

This PR takes advantage of the new system contract called "get_contract_metadata", which is used to determine if an account has a contract or not. This is useful to improve the security of the assets (see references).

Changes:

• New function System.getContractMetadata
• The previous System.checkAuthority has been renamed to System.checkAuthorityLegacy
• New function System.checkAuthority which calls getContractMetadata internally.
• New function System.checkCallContractAuthority which calls the checkAuthority and fill the arguments.
• System.requireAuthority updated.

References

• https://peakd.com/koinos/@jga/improve-security-koinos
• https://peakd.com/koinos/@jga/check-authority-2-testnet
• https://peakd.com/koinos/@jga/new-koinos-system-call-live-in-the-testnet
• https://peakd.com/koinos/@jga/gov-proposal-get-contract-metadata
• https://peakd.com/koinos/@jga/gov-proposal-in-koinos-mainnet-second-try

Checklist

• I have built this pull request locally
• I have ran the unit tests locally
• I have manually tested this pull request
• I have reviewed my pull request
• I have added any relevant tests

Demonstration

I deployed 3 contracts in mainnet: smart wallet, assets contract, and third party contract. These contracts interact between them to demonstrate the advantages of the new system call. They are working as expected.
You can follow the tests described in this post but using these addresses for mainnet:

• Assets contract - 15JPPMabyR4mphZBtJ18Hft6dQbHABtbSn
• Third party contract - 1LntH6U1C8M6TdDJaQc6NeBmWMYYuxhReA
• Wallet contract - 1KLB7yKvjjtbCDfT5VEfMgxiom233XBXiZ

[mvandeberg]

With the implicit calls to getArguments and getCaller in function signatures, do we want to add some internal caching so when those calls are made multiple times, we can short circuit and return the cached object?

[mvandeberg]

I have also requested @sgerbino's review on this PR to ensure correctness and usability before we release it to contract devs.

[joticajulian]

With the implicit calls to getArguments and getCaller in function signatures, do we want to add some internal caching so when those calls are made multiple times, we can short circuit and return the cached object?

Good suggestion. I just added a cache value for these 2 functions.

[mvandeberg]

Sorry for the delay in review. LGTM, I want @sgerbino to look at it as well before we merge.

[mvandeberg]

Looking at this again, there are no tests for this new behavior. We probably need to add contract metadata to MockVM so we can be sure this authority check works in the scenario it is intended to address.

[joticajulian]

I've been very busy in other topics. I'd appreciate if someone can work in the unit tests.