update to latest solitity

Author: tbocek

README.md

@@ -2,10 +2,10 @@
 
 # Testonator
 
-This library provides a JSON-RPC wrapper to a standalone Ethereum blockchain, used for testing purposes. It uses Solidity 0.4.25. It also provides an wrapper for web3j, where contracts do not have to be generated into Java classes. If your contract looks like this:
+This library provides a JSON-RPC wrapper to a standalone Ethereum blockchain, used for testing purposes. It uses Solidity 0.5.6. It also provides an wrapper for web3j, where contracts do not have to be generated into Java classes. If your contract looks like this:
 
 ```
-pragma solidity ^0.4.25;
+pragma solidity ^0.5.6;
                
 contract Example2 {
     uint256 public counter = 15;
@@ -38,14 +38,14 @@ Maven:
 <dependency>
     <groupId>io.iconator</groupId>
     <artifactId>testonator</artifactId>
-    <version>1.0.32</version>
+    <version>1.0.33</version>
 </dependency>
 ```
 
 Gradle:
 
 ```
-compile 'io.iconator:testonator:1.0.32'
+compile 'io.iconator:testonator:1.0.33'
 ```
 
 ## Example of JSON-RPC request

build.gradle

@@ -22,7 +22,7 @@ publishing {
 
 group 'io.iconator'
 archivesBaseName = 'testonator'
-version '1.0.32'
+version '1.0.33'
 
 sourceCompatibility = 1.8
 targetCompatibility = 1.8
@@ -37,7 +37,7 @@ repositories {
 
 dependencies {
     compile 'org.ethereum:ethereumj-core:1.10.0-RELEASE'
-    compile 'org.ethereum:solcJ-all:0.5.2'
+    compile 'org.ethereum:solcJ-all:0.5.6'
     compile 'com.github.briandilley.jsonrpc4j:jsonrpc4j:1.5.3'
     compile 'commons-io:commons-io:2.6'
     compile 'org.web3j:core:4.1.0'

src/test/resources/Utils.sol

@@ -49,46 +49,48 @@ library Utils {
     //From: https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/cryptography/ECDSA.sol
 
     /**
-    * @notice Recover signer address from a message by using his signature
-    * @param hash bytes32 message, the hash is the signed message. What is recovered is the signer address.
-    * @param sig bytes signature, the signature is generated using web3.eth.sign()
-    */
-    function recover(bytes32 hash, bytes memory sig) internal pure returns (address) {
-        //r is computed as the X coordinate of a point R, modulo the curve order n.
+     * @dev Recover signer address from a message by using their signature
+     * @param hash bytes32 message, the hash is the signed message. What is recovered is the signer address.
+     * @param signature bytes signature, the signature is generated using web3.eth.sign()
+     */
+    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
+        // Check the signature length
+        if (signature.length != 65) {
+            return (address(0));
+        }
+
+        // Divide the signature in r, s and v variables
         bytes32 r;
-        //s is (hash+rdA) / random number
         bytes32 s;
-        //v is used for public key recovery: https://bitcoin.stackexchange.com/questions/38351/ecdsa-v-r-s-what-is-v
         uint8 v;
 
-        //Check the signature length
-        if (sig.length != 65) {
-            return address(0);
-        }
-
-        // Divide the signature in r, s and v variables
+        // ecrecover takes the signature parameters, and the only way to get them
+        // currently is to use assembly.
+        // solhint-disable-next-line no-inline-assembly
         assembly {
-            r := mload(add(sig, 32))
-            s := mload(add(sig, 64))
-            v := byte(0, mload(add(sig, 96)))
+            r := mload(add(signature, 0x20))
+            s := mload(add(signature, 0x40))
+            v := byte(0, mload(add(signature, 0x60)))
         }
 
-        //EIP-2 still allows signature malleabality, remove this possibility
-        if(uint256(s) > uint256(0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0)) {
+        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
+        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
+        // the valid range for s in (281): 0 < s < secp256k1n ÷ 2 + 1, and for v in (282): v ∈ {27, 28}. Most
+        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
+        //
+        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
+        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
+        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
+        // these malleable signatures as well.
+        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
             return address(0);
         }
 
-        //removed the possibility of 0/1 in the signature, see:
-        //https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1622
-        //https://github.com/ethereum/EIPs/issues/865
-
-        // If the version is correct return the signer address
-        // see
-        // https://github.com/ethereum/go-ethereum/blob/master/core/types/transaction_signing.go#L195
         if (v != 27 && v != 28) {
             return address(0);
-        } else {
-            return ecrecover(hash, v, r, s);
         }
+
+        // If the signature is valid (and not malleable), return the signer address
+        return ecrecover(hash, v, r, s);
     }
 }