Removed drift check from Oracle Router and gas optimizations #1943

naddison36 · 2023-11-27T10:41:44Z

Changes

Removed the drift checks from the OracleRouter. Note the OETHOracleRouter does not do drift checks as its already done in the OETHVault.
Removed read of Oracle decimals from storage which saves close to 2k gas for stETH, rETH and frxETH. There is a slight increase in gas for WETH as it was not reading the Oracle decimals from storage.

Gas Testing

Before upgrade of OETHOracleRouter

|  Contract           ·  Method              ·  Min        ·  Max        ·  Avg        ·  # calls      ·  eur (avg)  │
······················|······················|·············|·············|·············|···············|··············
|  OETHOracleRouter   ·  price               ·      21935  ·      43431  ·      36034  ·            4  ·          -  │

WETH before

|  OETHOracleRouter   ·  price               ·          -  ·          -  ·      21935  ·            1  ·          -  │

stETH before

|  OETHOracleRouter   ·  price               ·          -  ·          -  ·      43387  ·            1  ·          -  │

After change

|  Contract           ·  Method              ·  Min        ·  Max        ·  Avg        ·  # calls      ·  eur (avg)  │
······················|······················|·············|·············|·············|···············|··············
|  OETHOracleRouter   ·  price               ·      21974  ·      41214  ·      34381  ·            4  ·          -  │

WETH after

|  OETHOracleRouter   ·  price               ·          -  ·          -  ·      21974  ·            1  ·          -  │

stETH after

|  OETHOracleRouter   ·  price               ·          -  ·          -  ·      41170  ·            1  ·          -  │

Review

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Refer to our documentation for more details about contract security best practices.

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Code reviewed by 2 reviewers.
Copy & paste code review security checklist below this checklist.
Unit tests pass
Slither tests pass with no warning
Echidna tests pass if PR includes changes to OUSD contract (not automated, run manually on local)

github-actions · 2023-11-27T10:42:22Z

	Warnings
⚠️	👀 This PR needs at least 2 reviewers

Generated by 🚫 dangerJS against 4bdf822

DanielVF · 2023-11-27T12:37:35Z

Seems like a great idea.

Might be good to write some kind of test (even if a one off script) that verifies that the answers are the same before and after the upgraded.

naddison36 · 2023-11-27T12:43:23Z

Seems like a great idea.

Might be good to write some kind of test (even if a one off script) that verifies that the answers are the same before and after the upgraded.

I added isDecimalsValid to the OracleRouter that validates the decimals returned from feedMetadata matches the decimals returned from the Oracle feed AggregatorV3Interface(_feed).decimals().
I check isDecimalsValid is true as part of the deploy script and have added checks to the fork tests.

sparrowDom

I think this is a great idea, a nice gas savings, since the Oracle decimals should never change.

Left some comments inline

sparrowDom · 2023-11-28T18:05:34Z

contracts/contracts/oracle/OracleRouter.sol

        } else if (asset == 0xD533a949740bb3306d119CC777fa900bA034cd52) {
            // https://data.chain.link/ethereum/mainnet/crypto-usd/crv-usd
            // Chainlink: CRV/USD
            feedAddress = 0xCd627aA160A6fA45Eb793D19Ef54f5062F20f33f;
            maxStaleness = 1 days + STALENESS_BUFFER;
+            decimals = 18;


Crv/Usd has 8 decimals: https://etherscan.io/address/0xcd627aa160a6fa45eb793d19ef54f5062f20f33f#readContract

sparrowDom · 2023-11-28T18:19:43Z

contracts/contracts/oracle/OracleRouter.sol

        } else if (asset == 0xD533a949740bb3306d119CC777fa900bA034cd52) {
            // https://data.chain.link/ethereum/mainnet/crypto-usd/crv-usd
            // Chainlink: CRV/USD
            feedAddress = 0xCd627aA160A6fA45Eb793D19Ef54f5062F20f33f;
            maxStaleness = 1 days + STALENESS_BUFFER;
+            decimals = 18;
        } else if (asset == 0x4e3FBD56CD56c3e72c1403e103b45Db9da5B9D2B) {
            // Chainlink: CVX/USD


Cvx/USD is also 8 decimals:
https://etherscan.io/address/0xd962fc30a72a84ce50161031391756bf2876af5d#readContract

can you also add this link into the comment for easier verification (like in the above feeds):
https://data.chain.link/ethereum/mainnet/crypto-usd/cvx-usd

sparrowDom · 2023-11-28T18:22:54Z

contracts/deploy/001_core.js

+    [assetAddresses.TUSD, oracleAddresses.chainlink.TUSD_USD, 8],
+    [assetAddresses.COMP, oracleAddresses.chainlink.COMP_USD, 8],
+    [assetAddresses.AAVE, oracleAddresses.chainlink.AAVE_USD, 8],
+    [assetAddresses.CRV, oracleAddresses.chainlink.CRV_USD, 18],


this should be 8 also

sparrowDom · 2023-11-28T18:23:02Z

contracts/deploy/001_core.js

+    [assetAddresses.COMP, oracleAddresses.chainlink.COMP_USD, 8],
+    [assetAddresses.AAVE, oracleAddresses.chainlink.AAVE_USD, 8],
+    [assetAddresses.CRV, oracleAddresses.chainlink.CRV_USD, 18],
+    [assetAddresses.CVX, oracleAddresses.chainlink.CVX_USD, 18],


sparrowDom · 2023-11-28T18:28:20Z

contracts/test/helpers.js

+    USDT: 8,
+    DAI: 8,
+    COMP: 8,
+    CVX: 18,


sparrowDom · 2023-11-28T18:28:24Z

contracts/test/helpers.js

+    DAI: 8,
+    COMP: 8,
+    CVX: 18,
+    CRV: 18,


aslo 8 I think?

sparrowDom · 2023-11-28T22:17:09Z

There is another issue with these changes. The currently implemented floorPrice of the VaultCore doesn't do any of its own checks of Oracle drift. The potential issue with the current implementation is that 1 underlying asset could de-peg: e.g. rEth to 0.2 worth of ETH, and an Oracle of another asset could be manipulated to return 1.8 ETH still totaling a floorPrice at 1. While in the current master a drift check at the 1.8 ETH price would fail since it exceedes the 1.3 ETH of maximum drift and prevent such situation.

We should probably utilize the _toUnitPrice by calling _toUnitPrice(asset, true) though that function might need changing since we don't want it to perform the require(price >= MINT_MINIMUM_UNIT_PRICE, "Asset price below peg"); part of the check.

naddison36 added 5 commits November 23, 2023 22:50

Removed drift protection from Oracle Router

757acff

Hardcode Oracle Router decimals for gas savings

8474598

Added isDecimalsValid to OETHOracleRouter fork tests

a3e8d93

removed single asset price check

9161957

Added under 0.7 and over 1.0 frxETH price tests

4bdf822

naddison36 requested review from sparrowDom, DanielVF and shahthepro as code owners November 27, 2023 10:41

naddison36 added contracts Works related to contracts OETH OETH related things labels Nov 27, 2023

rafaelugolini temporarily deployed to preview-ousd-nicka-oeth-qrlaht November 27, 2023 10:42 Inactive

sparrowDom requested changes Nov 28, 2023

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Removed drift check from Oracle Router and gas optimizations #1943

Removed drift check from Oracle Router and gas optimizations #1943

naddison36 commented Nov 27, 2023

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DanielVF commented Nov 27, 2023

naddison36 commented Nov 27, 2023

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sparrowDom commented Nov 28, 2023 •

edited

Removed drift check from Oracle Router and gas optimizations #1943

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Removed drift check from Oracle Router and gas optimizations #1943

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naddison36 commented Nov 27, 2023

Changes

Gas Testing

Review

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sparrowDom commented Nov 28, 2023 • edited

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edited