1+ // Copyright (C) 2018 Argent Labs Ltd. <https://argent.xyz>
2+
3+ // This program is free software: you can redistribute it and/or modify
4+ // it under the terms of the GNU General Public License as published by
5+ // the Free Software Foundation, either version 3 of the License, or
6+ // (at your option) any later version.
7+
8+ // This program is distributed in the hope that it will be useful,
9+ // but WITHOUT ANY WARRANTY; without even the implied warranty of
10+ // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11+ // GNU General Public License for more details.
12+
13+ // You should have received a copy of the GNU General Public License
14+ // along with this program. If not, see <http://www.gnu.org/licenses/>.
15+
116pragma solidity ^ 0.5.4 ;
217
318/**
419 * @title MultiSig
520 * @dev Simple MultiSig using off-chain signing.
6- * @author Julien Niset - <julien@argent.im >
21+ * @author Julien Niset - <julien@argent.xyz >
722 */
823contract MultiSigWallet {
924
1025 uint constant public MAX_OWNER_COUNT = 10 ;
1126
1227 // Incrementing counter to prevent replay attacks
13- uint256 public nonce;
14- // The threshold
15- uint256 public threshold;
28+ uint256 public nonce;
29+ // The threshold
30+ uint256 public threshold;
1631 // The number of owners
1732 uint256 public ownersCount;
1833 // Mapping to check if an address is an owner
19- mapping (address => bool ) public isOwner;
34+ mapping (address => bool ) public isOwner;
2035
2136 // Events
2237 event OwnerAdded (address indexed owner );
@@ -26,7 +41,8 @@ contract MultiSigWallet {
2641 event Received (uint256 indexed value , address indexed from );
2742
2843 /**
29- * @dev Throws is the calling account is not the multisig.
44+ * @dev Throws if the calling account is not the multisig.
45+ * @dev Mainly used for enforcing the use of internal functions through the "execute" function
3046 */
3147 modifier onlyWallet () {
3248 require (msg .sender == address (this ), "MSW: Calling account is not wallet " );
@@ -36,23 +52,23 @@ contract MultiSigWallet {
3652 /**
3753 * @dev Constructor.
3854 * @param _threshold The threshold of the multisig.
39- * @param _owners The owners of the multisig.
55+ * @param _owners The initial set of owners of the multisig.
4056 */
4157 constructor (uint256 _threshold , address [] memory _owners ) public {
4258 require (_owners.length > 0 && _owners.length <= MAX_OWNER_COUNT, "MSW: Not enough or too many owners " );
4359 require (_threshold > 0 && _threshold <= _owners.length , "MSW: Invalid threshold " );
4460 ownersCount = _owners.length ;
4561 threshold = _threshold;
46- for (uint256 i = 0 ; i < _owners.length ; i++ ) {
62+ for (uint256 i = 0 ; i < _owners.length ; i++ ) {
4763 isOwner[_owners[i]] = true ;
4864 emit OwnerAdded (_owners[i]);
4965 }
5066 emit ThresholdChanged (_threshold);
5167 }
5268
5369 /**
54- * @dev Only entry point of the multisig. The method will execute any transaction provided that it
55- * receieved enough signatures from the wallet owners.
70+ * @dev Only entry point of the multisig. The method will execute any transaction provided that it
71+ * receieved enough signatures from the wallet owners.
5672 * @param _to The destination address for the transaction to execute.
5773 * @param _value The value parameter for the transaction to execute.
5874 * @param _data The data parameter for the transaction to execute.
@@ -68,27 +84,28 @@ contract MultiSigWallet {
6884 nonce += 1 ;
6985 uint256 valid = 0 ;
7086 address lastSigner = address (0 );
71- for (uint256 i = 0 ; i < count; i++ ) {
87+ for (uint256 i = 0 ; i < count; i++ ) {
7288 (v,r,s) = splitSignature (_signatures, i);
7389 address recovered = ecrecover (keccak256 (abi.encodePacked ("\x19Ethereum Signed Message:\n32 " ,txHash)), v, r, s);
7490 require (recovered > lastSigner, "MSW: Badly ordered signatures " ); // make sure signers are different
7591 lastSigner = recovered;
76- if (isOwner[recovered]) {
92+ if (isOwner[recovered]) {
7793 valid += 1 ;
78- if (valid >= threshold) {
94+ if (valid >= threshold) {
95+ // solium-disable-next-line security/no-call-value
7996 (bool success ,) = _to.call.value (_value)(_data);
8097 require (success, "MSW: External call failed " );
8198 emit Executed (_to, _value, _data);
8299 return ;
83100 }
84101 }
85102 }
86- // If we reach that point then the transaction is not executed
103+ // If not enough signatures for threshold, then the transaction is not executed
87104 revert ("MSW: Not enough valid signatures " );
88105 }
89106
90107 /**
91- * @dev Adds an owner to the multisig. This method can only be called by the multisig itself
108+ * @dev Adds an owner to the multisig. This method can only be called by the multisig itself
92109 * (i.e. it must go through the execute method and be confirmed by the owners).
93110 * @param _owner The address of the new owner.
94111 */
@@ -101,9 +118,9 @@ contract MultiSigWallet {
101118 }
102119
103120 /**
104- * @dev Removes an owner from the multisig. This method can only be called by the multisig itself
121+ * @dev Removes an owner from the multisig. This method can only be called by the multisig itself
105122 * (i.e. it must go through the execute method and be confirmed by the owners).
106- * @param _owner The address of the removed owner.
123+ * @param _owner The address of the owner to be removed .
107124 */
108125 function removeOwner (address _owner ) public onlyWallet {
109126 require (ownersCount > threshold, "MSW: Too few owners left " );
@@ -114,7 +131,7 @@ contract MultiSigWallet {
114131 }
115132
116133 /**
117- * @dev Changes the threshold of the multisig. This method can only be called by the multisig itself
134+ * @dev Changes the threshold of the multisig. This method can only be called by the multisig itself
118135 * (i.e. it must go through the execute method and be confirmed by the owners).
119136 * @param _newThreshold The new threshold.
120137 */
@@ -125,28 +142,29 @@ contract MultiSigWallet {
125142 }
126143
127144 /**
128- * @dev Makes it possible for the multisig to receive ETH.
129- */
130- function () external payable {
131- emit Received (msg .value , msg .sender );
132- }
133-
134- /**
135145 * @dev Parses the signatures and extract (r, s, v) for a signature at a given index.
136- * A signature is {bytes32 r}{bytes32 s}{uint8 v} in compact form and signatures are concatenated.
146+ * A signature is {bytes32 r}{bytes32 s}{uint8 v} in compact form where the signatures are concatenated.
137147 * @param _signatures concatenated signatures
138148 * @param _index which signature to read (0, 1, 2, ...)
139149 */
140150 function splitSignature (bytes memory _signatures , uint256 _index ) internal pure returns (uint8 v , bytes32 r , bytes32 s ) {
141151 // we jump 32 (0x20) as the first slot of bytes contains the length
142152 // we jump 65 (0x41) per signature
143153 // for v we load 32 bytes ending with v (the first 31 come from s) tehn apply a mask
154+ // solium-disable-next-line security/no-inline-assembly
144155 assembly {
145156 r := mload (add (_signatures, add (0x20 ,mul (0x41 ,_index))))
146157 s := mload (add (_signatures, add (0x40 ,mul (0x41 ,_index))))
147158 v := and (mload (add (_signatures, add (0x41 ,mul (0x41 ,_index)))), 0xff )
148159 }
149- require (v == 27 || v == 28 , "MSW: Invalid v " );
160+ require (v == 27 || v == 28 , "MSW: Invalid v " );
161+ }
162+
163+ /**
164+ * @dev Fallback function to allow the multisig to receive ETH, which will fail if not implemented
165+ */
166+ function () external payable {
167+ emit Received (msg .value , msg .sender );
150168 }
151169
152170}
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