Rigor Protocol contest - JC's results

Community lending and instant payments for new home construction.

General Information

Platform: Code4rena

Start Date: 01/08/2022

Pot Size: $50,000 USDC

Total HM: 26

Participants: 133

Period: 5 days

Judge: Jack the Pug

Total Solo HM: 6

Id: 151

League: ETH

Rigor Protocol

Findings Distribution

Researcher Performance

Rank: 56/133

Findings: 2

Award: $66.27

🌟 Selected for report: 0

🚀 Solo Findings: 0

External Links

Code4rena Contest Page Github Contest Repository Github Findings Repository Rigor Protocol

Findings Information

🌟 Selected for report: Lambda

Also found by: 0x1f8b, 0x52, 0xA5DF, 0xNazgul, 0xNineDec, 0xSmartContract, 0xSolus, 0xf15ers, 0xkatana, 0xsolstars, 8olidity, Aymen0909, Bahurum, Bnke0x0, CertoraInc, Chom, CodingNameKiki, Deivitto, Dravee, ElKu, Extropy, Funen, GalloDaSballo, Guardian, IllIllI, JC, Jujic, MEP, Noah3o6, ReyAdmirado, Rohan16, Rolezn, Ruhum, Sm4rty, SooYa, Soosh, Throne6g, TomJ, Tomio, TrungOre, Waze, Yiko, _Adam, __141345__, a12jmx, ajtra, ak1, arcoun, asutorufos, ayeslick, benbaessler, berndartmueller, bin2chen, bobirichman, brgltd, bulej93, byndooa, c3phas, codexploder, cryptonue, cryptphi, defsec, delfin454000, dipp, djxploit, erictee, exd0tpy, fatherOfBlocks, gogo, hake, hansfriese, horsefacts, hyh, ignacio, indijanc, joestakey, kaden, mics, minhquanym, neumo, obront, oyc_109, p_crypt0, pfapostol, poirots, rbserver, robee, rokinot, rotcivegaf, sach1r0, saian, samruna, saneryee, scaraven, sikorico, simon135, sseefried, supernova

Awards

40.8799 USDC - $40.88

Labels

bug

QA (Quality Assurance)

valid

External Links

Link to GitHub issue

L-01 Unsafe casts and usage of IERC20

not all ERC20 contracts define decimals() since it’s optional in the spec. Use safeDecimals() instead.

Instances include: https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L16 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L47 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L56

N-01 Use a more recent version of solidity

Use a solidity version of at least 0.8.10 to have external calls skip contract existence checks if the external call has a return value Use a solidity version of at least 0.8.12 to get string.concat() instead of abi.encodePacked(<str>,<str>) Use a solidity version of at least 0.8.13 to get the ability to use using for with a list of free functions

N-02 Remove commented out code

Instances include: https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L92 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L93 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L94 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L101 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L102

#0 - zgorizzo69
2022-08-07T09:15:05Z

On one hand decimal is indeed optional but on the other hand rigor whitelist the token to use. Nonetheless it can be nice to have that safeguard in the future. interesting optimizations with latest solidity version although we can't use concat as we can't decode

Findings Information

🌟 Selected for report: c3phas

Also found by: 0x040, 0x1f8b, 0xA5DF, 0xNazgul, 0xSmartContract, 0xSolus, 0xc0ffEE, 0xkatana, 0xsam, 8olidity, Aymen0909, Bnke0x0, CertoraInc, Chinmay, Chom, CodingNameKiki, Deivitto, Dravee, ElKu, Extropy, Fitraldys, Funen, GalloDaSballo, Guardian, IllIllI, JC, Lambda, MEP, Metatron, MiloTruck, Noah3o6, NoamYakov, PaludoX0, ReyAdmirado, Rohan16, Rolezn, Ruhum, Sm4rty, SooYa, TomJ, Tomio, Waze, _Adam, __141345__, a12jmx, ajtra, ak1, apostle0x01, asutorufos, ballx, benbaessler, bharg4v, bobirichman, brgltd, cryptonue, defsec, delfin454000, dharma09, djxploit, durianSausage, eierina, erictee, fatherOfBlocks, gerdusx, gogo, hake, hyh, ignacio, jag, kaden, kyteg, lucacez, mics, minhquanym, oyc_109, pfapostol, rbserver, ret2basic, robee, rokinot, sach1r0, saian, samruna, scaraven, sikorico, simon135, supernova, teddav, tofunmi, zeesaw

Awards

25.3906 USDC - $25.39

Labels

bug

G (Gas Optimization)

valid

External Links

Link to GitHub issue

G-01 ++i costs less gas than i++, especially when it's used in for loops
G-02 Use nested multiple require instead of && operator G-03 Use custom errors rather than revert()/require() strings to save deployment gas G-04 Comparison operators G-05 Use a more recent version of solidity G-06 <x> += <y> costs more gas than <x> = <x> + <y> for state variables G-07 Usage of uints/ints smaller than 32 bytes (256 bits) incurs overhead G-08 Using private rather than public for constants saves gas G-09 calldata instead of memory for read-only function parameter G-10 ++i/i++ should be unchecked{++i}/unchecked{i++} G-11 <array>.length should not be looked up in every loop of a for-loop G-12 internal functions only called once can be inlined to save gas G-13 Using > 0 costs more gas than != 0 when used on a uint in a require() statement G-14 Empty blocks should be removed or emit something G-15 Using bools for storage incurs overhead G-16 Using storage instead of memory for structs/arrays saves gas

G-01 ++i costs less gas than i++, especially when it's used in for loops

There are 8 instances: HomeFiProxy.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFiProxy.sol#L87 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFiProxy.sol#L136

Project.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L248 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L311 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L322 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L603

Community.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L624

Tasks.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/Tasks.sol#L181

G-02 Use nested multiple require instead of && operator

Require statements including conditions with the && operator can be broken down in multiple require statements to save gas.

There is 1 instance: Community.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L353-L357

G-03 Use custom errors rather than revert()/require() strings to save deployment gas

Custom errors from Solidity 0.8.4 are cheaper than require strings (cheaper deployment cost and runtime cost when the revert condition is met) while providing the same amount of information, as explained here https://blog.soliditylang.org/2021/04/21/custom-errors/ Custom errors are defined using the error statement, which can be used inside and outside of contracts (including interfaces and libraries).

There are 68 instances: DebtToken.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L33 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L50 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L96 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L104

ProjectFactory.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/ProjectFactory.sol#L36 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/ProjectFactory.sol#L66 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/ProjectFactory.sol#L84

HomeFiProxy.so https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFiProxy.sol#L41 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFiProxy.sol#L81 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFiProxy.sol#L105 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFiProxy.sol#L133

Disputes.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L39 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L46 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L52 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L61 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L106 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L183

HomeFi.so https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L73 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L78 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L84 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L142 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L191 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L255

Tasks.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/Tasks.sol#L44 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/Tasks.sol#L50 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/Tasks.sol#L58 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/Tasks.sol#L124

G-04 Comparison operators

In the EVM, there is no opcode for >= or <=. When using greater than or equal, two operations are performed: > and =. Using strict comparison operators hence saves gas.

There are 14 instances: Disputes.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L107

Community.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L354 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L355 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L401 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L792

Mitigation: Replace <= with <, and >= with >. Do not forget to increment/decrement the compared variable example: -require(maxFee >= minFee, Error.INVALID_AMOUNT); +require(maxFee > minFee - 1, Error.INVALID_AMOUNT);

G-05 Use a more recent version of solidity

G-06 <x> += <y> costs more gas than <x> = <x> + <y> for state variables (also <x> -= <y> vs <x> = <x> - <y>)

G-07 Usage of uints/ints smaller than 32 bytes (256 bits) incurs overhead

When using elements that are smaller than 32 bytes, your contract’s gas usage may be higher. This is because the EVM operates on 32 bytes at a time. Therefore, if the element is smaller than that, the EVM must use more operations in order to reduce the size of the element from 32 bytes to the desired size. https://docs.soliditylang.org/en/v0.8.11/internals/layout_in_storage.html Use a larger size then downcast where needed

There are 9 instances: DebtToken.so https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L16 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L47 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L82

Disputes.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L100 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L103 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L107 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L507

G-08 Using private rather than public for constants saves gas

If needed, the value can be read from the verified contract source code. Savings are due to the compiler not having to create non-payable getter functions for deployment calldata, and not adding another entry to the method ID table.

There is 1 instance: Project.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L60

G-09 calldata instead of memory for read-only function parameter

If a reference type function parameter is read-only, it is cheaper in gas to use calldata instead of memory. Calldata is a non-modifiable, non-persistent area where function arguments are stored, and behaves mostly like memory. Try to use calldata as a data location because it will avoid copies and also makes sure that the data cannot be modified.

There are 13 instances: DebtToken.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L45 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/DebtToken.sol#L46

Disputes.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L236 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L254 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L268

HomeFi.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L210 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L284

Project.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L878

Community.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L488 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L761 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L874

G-10 ++i/i++ should be unchecked{++i}/unchecked{i++} when it is not possible for them to overflow, as is the case when used in for- and while-loops

The unchecked keyword is new in solidity version 0.8.0, so this only applies to that version or higher, which these instances are. This saves 30-40 gas per loop: https://gist.github.com/hrkrshnn/ee8fabd532058307229d65dcd5836ddc#the-increment-in-for-loop-post-condition-can-be-made-unchecked

Community.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L624

Tasks.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/Tasks.sol#L181

G-11 <array>.length should not be looked up in every loop of a for-loop

The overheads outlined below are PER LOOP, excluding the first loop storage arrays incur a Gwarmaccess (100 gas) memory arrays use MLOAD (3 gas) calldata arrays use CALLDATALOAD (3 gas) Caching the length changes each of these to a DUP<N> (3 gas), and gets rid of the extra DUP<N> needed to store the stack offset.

There is 1 instance: https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L603

G-12 internal functions only called once can be inlined to save gas

Not inlining costs 20 to 40 gas because of two extra JUMP instructions and additional stack operations needed for function calls.

There are 23 instances: HomeFiProxy.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFiProxy.sol#L197-L200 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFiProxy.sol#L216-L219

Disputes.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L236-L238 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L254-L256 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L268-L270

HomeFi.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L284-L287 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L303-L308 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L314-L319

Project.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L747-L751 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L791-L793 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L830-L834 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L875-L880

Community.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L757-L762 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L824-L828 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L899-L904 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L910-L915

SignatureDecoder.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/SignatureDecoder.sol#L20-L24 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/SignatureDecoder.sol#L43-L47 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/SignatureDecoder.sol#L61-L69

Tasks.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/Tasks.sol#L106-L109 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/Tasks.sol#L119-L122 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/Tasks.sol#L175-L179 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/libraries/Tasks.sol#L191-L195

G-13 Using > 0 costs more gas than != 0 when used on a uint in a require() statement

This change saves 6 gas per instance. https://aws1.discourse-cdn.com/business6/uploads/zeppelin/original/2X/3/363a367d6d68851f27d2679d10706cd16d788b96.png

There are 10 instances: Disputes.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L107

HomeFi.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L245

Project.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L195 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L380 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L601 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L601

Community.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L261 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L427 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L764 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L840

G-14 Empty blocks should be removed or emit something

The code should be refactored such that they no longer exist, or the block should do something useful, such as emitting an event or reverting. If the contract is meant to be extended, the contract should be abstract and the function signatures be added without any default implementation. If the block is an empty if-statement block to avoid doing subsequent checks in the else-if/else conditions, the else-if/else conditions should be nested under the negation of the if-statement, because they involve different classes of checks, which may lead to the introduction of errors when the code is later modified (if(x){}else if(y){...}else{...} => if(!x){if(y){...}else{...}})

There is 1 instance: https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L88

G-15 Using bools for storage incurs overhead

Booleans are more expensive than uint256 or any type that takes up a full word because each write operation emits an extra SLOAD to first read the slot's contents, replace the bits taken up by the boolean, and then write back. This is the compiler's defense against contract upgrades and pointer aliasing, and it cannot be disabled. https://github.com/OpenZeppelin/openzeppelin-contracts/blob/58f635312aa21f947cae5f8578638a85aa2519f5/contracts/security/ReentrancyGuard.sol#L23-L27

There are 9 instances: HomeFiProxy.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFiProxy.sol#L30

Disputes.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Disputes.sol#L144

HomeFi.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L50

Project.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L68 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L69 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L156 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L582 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L750

Community.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L55

Mitigation: Use uint256(1) and uint256(2) for true/false to avoid a Gwarmaccess (100 gas) for the extra SLOAD, and to avoid Gsset (20000 gas) when changing from ‘false’ to ‘true’, after having been ‘true’ in the past

G-16 Using storage instead of memory for structs/arrays saves gas

When fetching data from a storage location, assigning the data to a memory variable causes all fields of the struct/array to be read from storage, which incurs a Gcoldsload (2100 gas) for each field of the struct/array. If the fields are read from the new memory variable, they incur an additional MLOAD rather than a cheap stack read. Instead of declearing the variable with the memory keyword, declaring the variable with the storage keyword and caching any fields that need to be re-read in stack variables, will be much cheaper, only incuring the Gcoldsload for the fields actually read. The only time it makes sense to read the whole struct/array into a memory variable, is if the full struct/array is being returned by the function, is being passed to a function that requires memory, or if the array/struct is being read from another memory array/struct

There are 2 instances: Community.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L619

Project.sol https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Project.sol#L591

G-17 Multiple address mappings can be combined into a single mapping of an address to a struct, where appropriate

Saves a storage slot for the mapping. Depending on the circumstances and sizes of types, can avoid a Gsset (20000 gas) per mapping combined. Reads and subsequent writes can also be cheaper when a function requires both values and they both fit in the same storage slot. Finally, if both fields are accessed in the same function, can save ~42 gas per access due to not having to recalculate the key’s keccak256 hash (Gkeccak256 - 30 gas) and that calculation’s associated stack operations.

There are 2 instances: https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/HomeFi.sol#L64-L66 https://github.com/code-423n4/2022-08-rigor/blob/b17b2a11d04289f9e927c71703b42771dd7b86a4/contracts/Community.sol#L59-L61

Rigor Protocol contest - JC's results

Community lending and instant payments for new home construction.

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Table of Contents:

L-01 Unsafe casts and usage of IERC20

N-01 Use a more recent version of solidity

N-02 Remove commented out code

#0 - zgorizzo69
2022-08-07T09:15:05Z

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Table of Contents:

G-01 ++i costs less gas than i++, especially when it's used in for loops

G-02 Use nested multiple require instead of && operator

G-03 Use custom errors rather than revert()/require() strings to save deployment gas

G-04 Comparison operators

G-05 Use a more recent version of solidity

G-06 <x> += <y> costs more gas than <x> = <x> + <y> for state variables (also <x> -= <y> vs <x> = <x> - <y>)

G-07 Usage of uints/ints smaller than 32 bytes (256 bits) incurs overhead

G-08 Using private rather than public for constants saves gas

G-09 calldata instead of memory for read-only function parameter

G-10 ++i/i++ should be unchecked{++i}/unchecked{i++} when it is not possible for them to overflow, as is the case when used in for- and while-loops

G-11 <array>.length should not be looked up in every loop of a for-loop

G-12 internal functions only called once can be inlined to save gas

G-13 Using > 0 costs more gas than != 0 when used on a uint in a require() statement

G-14 Empty blocks should be removed or emit something

G-15 Using bools for storage incurs overhead

G-16 Using storage instead of memory for structs/arrays saves gas

G-17 Multiple address mappings can be combined into a single mapping of an address to a struct, where appropriate

Rigor Protocol contest - JC's results

Community lending and instant payments for new home construction.

General Information

Findings Distribution

Researcher Performance

External Links

[Q-24] QA Report - $40.88

Findings Information

Awards

Labels

External Links

Table of Contents:

L-01 Unsafe casts and usage of IERC20

N-01 Use a more recent version of solidity

N-02 Remove commented out code

#0 - zgorizzo692022-08-07T09:15:05Z

[G-15] Gas Report - $25.39

Findings Information

Awards

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Table of Contents:

G-01 ++i costs less gas than i++, especially when it's used in for loops

G-02 Use nested multiple require instead of && operator

G-03 Use custom errors rather than revert()/require() strings to save deployment gas

G-04 Comparison operators

G-05 Use a more recent version of solidity

G-06 <x> += <y> costs more gas than <x> = <x> + <y> for state variables (also <x> -= <y> vs <x> = <x> - <y>)

G-07 Usage of uints/ints smaller than 32 bytes (256 bits) incurs overhead

G-08 Using private rather than public for constants saves gas

G-09 calldata instead of memory for read-only function parameter

G-10 ++i/i++ should be unchecked{++i}/unchecked{i++} when it is not possible for them to overflow, as is the case when used in for- and while-loops

G-11 <array>.length should not be looked up in every loop of a for-loop

G-12 internal functions only called once can be inlined to save gas

G-13 Using > 0 costs more gas than != 0 when used on a uint in a require() statement

G-14 Empty blocks should be removed or emit something

G-15 Using bools for storage incurs overhead

G-16 Using storage instead of memory for structs/arrays saves gas

G-17 Multiple address mappings can be combined into a single mapping of an address to a struct, where appropriate

#0 - zgorizzo69
2022-08-07T09:15:05Z