Axelar Network v2 contest - lucacez's results

MISSING CHECKS FOR ADDRESS(0X0) WHEN ASSIGNING VALUES TO ADDRESS STATE VARIABLES

1- File: contracts/deposit-service/AxelarDepositService.sol (line 19)

        receiverImplementation = address(new ReceiverImplementation(gateway, wrappedSymbol));

2- File: contracts/deposit-service/AxelarDepositService.sol (line 27)

                gatewayAddress = gatewayAddress_;

CONST/INMUTABLE variables must be written in uppercase letters

1- File: contracts/deposit-service/AxelarDepositService.sol (line 16)

    address public immutable receiverImplementation;

2- File: contracts/deposit-service/DepositBase.sol (line 13)

    address public immutable gateway;

3- File: contracts/deposit-service/DepositBase.sol (line 14)

    bytes32 internal immutable wrappedSymbolBytes;

4- File: xc20/contracts/XC20Wrapper.sol (line 24)

    address public immutable gatewayAddress;

USE A MORE RECENT VERSION OF SOLIDITY

Use a solidity version of at least 0.8.12 to get string.concat() to be used instead of abi.encodePacked(<str>,<str>)

++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

1- File: contracts/AxelarGateway.sol (line 195)

        for (uint256 i; i < adminCount; ++i) {

2- File: contracts/AxelarGateway.sol (line 207)

        for (uint256 i = 0; i < symbols.length; i++) {

3- File: contracts/AxelarGateway.sol (line 292)

        for (uint256 i; i < commandsLength; ++i) {

4- File: contracts/gas-service/AxelarGasService.sol (line 123)

        for (uint256 i; i < tokens.length; i++) {

5- File: contracts/deposit-service/AxelarDepositService.sol (line 114)

        for (uint256 i; i < refundTokens.length; i++) {

6- File: contracts/deposit-service/AxelarDepositService.sol (line 168)

        for (uint256 i; i < refundTokens.length; i++) {

7- File: contracts/deposit-service/AxelarDepositService.sol (line 204)

        for (uint256 i; i < refundTokens.length; i++) {

8- File: contracts/auth/AxelarAuthWeighted.sol (line 17)

        for (uint256 i; i < recentOperators.length; ++i) {

9- File: contracts/auth/AxelarAuthWeighted.sol (line 69)

        for (uint256 i = 0; i < weightsLength; ++i) {

10- File: contracts/auth/AxelarAuthWeighted.sol (line 98)

        for (uint256 i = 0; i < signatures.length; ++i) {

11- File: contracts/auth/AxelarAuthWeighted.sol (line 116)

        for (uint256 i; i < accounts.length - 1; ++i) {

++I COSTS LESS GAS THAN I++, ESPECIALLY WHEN IT’S USED IN FOR-LOOPS (--I/I-- TOO)

1- File: contracts/AxelarGateway.sol (line 207)

        for (uint256 i = 0; i < symbols.length; i++) {

2- File: contracts/gas-service/AxelarGasService.sol (line 123)

        for (uint256 i; i < tokens.length; i++) {

3- File: contracts/deposit-service/AxelarDepositService.sol (line 114)

        for (uint256 i; i < refundTokens.length; i++) {

4- File: contracts/deposit-service/AxelarDepositService.sol (line 168)

        for (uint256 i; i < refundTokens.length; i++) {

5- File: contracts/deposit-service/AxelarDepositService.sol (line 204)

        for (uint256 i; i < refundTokens.length; i++) {

<ARRAY>.LENGTH SHOULD NOT BE LOOKED UP IN EVERY LOOP OF A FOR-LOOP

Even memory arrays incur the overhead of bit tests and bit shifts to calculate the array length

1- File: contracts/AxelarGateway.sol (line 207)

        for (uint256 i = 0; i < symbols.length; i++) {

2- File: contracts/gas-service/AxelarGasService.sol (line 123)

        for (uint256 i; i < tokens.length; i++) {

3- File: contracts/deposit-service/AxelarDepositService.sol (line 114)

        for (uint256 i; i < refundTokens.length; i++) {

4- File: contracts/deposit-service/AxelarDepositService.sol (line 168)

        for (uint256 i; i < refundTokens.length; i++) {

5- File: contracts/deposit-service/AxelarDepositService.sol (line 204)

        for (uint256 i; i < refundTokens.length; i++) {

6- File: contracts/auth/AxelarAuthWeighted.sol (line 17)

        for (uint256 i; i < recentOperators.length; ++i) {

7- File: contracts/auth/AxelarAuthWeighted.sol (line 98)

        for (uint256 i = 0; i < signatures.length; ++i) {

8- File: contracts/auth/AxelarAuthWeighted.sol (line 116)

        for (uint256 i; i < accounts.length - 1; ++i) {

IT COSTS MORE GAS TO INITIALIZE NON-CONSTANT/NON-IMMUTABLE VARIABLES TO ZERO THAN TO LET THE DEFAULT OF ZERO BE APPLIED

Not overwriting the default for stack variables saves 8 gas. Storage and memory variables have larger savings

1- File: contracts/AxelarGateway.sol (line 207)

        for (uint256 i = 0; i < symbols.length; i++) {

2- File: contracts/auth/AxelarAuthWeighted.sol (line 69)

        for (uint256 i = 0; i < weightsLength; ++i) {

3- File: contracts/auth/AxelarAuthWeighted.sol (line 98)

        for (uint256 i = 0; i < signatures.length; ++i) {

<X> += <Y> COSTS MORE GAS THAN <X> = <X> + <Y> FOR STATE VARIABLES

There are 2 instances of this issue:

File: contracts/auth/AxelarAuthWeighted.sol

70:             totalWeight += newWeights[i];

105:           weight += weights[operatorIndex];

https://github.com/code-423n4/2022-07-axelar/blob/9c4c44b94cddbd48b9baae30051a4e13cbe39539/contracts/auth/AxelarAuthWeighted.sol