Extract USDC approval signing into method on PolygonKey

nimiq · Oct 13, 2023 · e6cc0e4 · e6cc0e4
1 parent 151e112
commit e6cc0e4
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Showing 3 changed files with 72 additions and 96 deletions.
diff --git a/src/lib/polygon/PolygonKey.js b/src/lib/polygon/PolygonKey.js
@@ -1,6 +1,7 @@
 /* global Nimiq */
 /* global Errors */
 /* global ethers */
+/* global CONFIG */
 
 class PolygonKey { // eslint-disable-line no-unused-vars
     /**
@@ -45,6 +46,57 @@ class PolygonKey { // eslint-disable-line no-unused-vars
         return wallet._signTypedData(domain, types, value);
     }
 
+    /**
+     * @param {string} path
+     * @param {ethers.Contract} usdcContract
+     * @param {string} forwarderContractAddress
+     * @param {ethers.BigNumber} approvalAmount
+     * @param {number} tokenNonce
+     * @param {string} fromAddress
+     * @returns {Promise<{sigR: string, sigS: string, sigV: number}>}
+     */
+    async signUsdcApproval(path, usdcContract, forwarderContractAddress, approvalAmount, tokenNonce, fromAddress) {
+        const functionSignature = usdcContract.interface.encodeFunctionData(
+            'approve',
+            [forwarderContractAddress, approvalAmount],
+        );
+
+        // TODO: Make the domain parameters configurable in the request?
+        const domain = {
+            name: 'USD Coin (PoS)', // This is currently the same for testnet and mainnet
+            version: '1', // This is currently the same for testnet and mainnet
+            verifyingContract: CONFIG.USDC_CONTRACT_ADDRESS,
+            salt: ethers.utils.hexZeroPad(ethers.utils.hexlify(CONFIG.POLYGON_CHAIN_ID), 32),
+        };
+
+        const types = {
+            MetaTransaction: [
+                { name: 'nonce', type: 'uint256' },
+                { name: 'from', type: 'address' },
+                { name: 'functionSignature', type: 'bytes' },
+            ],
+        };
+
+        const message = {
+            nonce: tokenNonce,
+            from: fromAddress,
+            functionSignature,
+        };
+
+        const signature = await this.signTypedData(
+            path,
+            domain,
+            types,
+            message,
+        );
+
+        const sigR = signature.slice(0, 66); // 0x prefix plus 32 bytes = 66 characters
+        const sigS = `0x${signature.slice(66, 130)}`; // 32 bytes = 64 characters
+        const sigV = parseInt(signature.slice(130, 132), 16); // last byte = 2 characters
+
+        return { sigR, sigS, sigV };
+    }
+
     /**
      * @param {string} path
      * @param {Uint8Array} message - A byte array

diff --git a/src/request/sign-polygon-transaction/SignPolygonTransaction.js b/src/request/sign-polygon-transaction/SignPolygonTransaction.js
@@ -118,57 +118,19 @@ class SignPolygonTransaction {
         const polygonKey = new PolygonKey(key);
 
         if (request.description.name === 'transferWithApproval') {
-            // Sign approval
-            const usdcContract = new ethers.Contract(
-                CONFIG.USDC_CONTRACT_ADDRESS,
-                PolygonContractABIs.USDC_CONTRACT_ABI,
-            );
-
-            const functionSignature = usdcContract.interface.encodeFunctionData(
-                'approve',
-                [CONFIG.USDC_TRANSFER_CONTRACT_ADDRESS, request.description.args.approval],
-            );
-
-            // TODO: Make the domain parameters configurable in the request?
-            const domain = {
-                name: 'USD Coin (PoS)', // This is currently the same for testnet and mainnet
-                version: '1', // This is currently the same for testnet and mainnet
-                verifyingContract: CONFIG.USDC_CONTRACT_ADDRESS,
-                salt: ethers.utils.hexZeroPad(ethers.utils.hexlify(CONFIG.POLYGON_CHAIN_ID), 32),
-            };
-
-            const types = {
-                MetaTransaction: [
-                    { name: 'nonce', type: 'uint256' },
-                    { name: 'from', type: 'address' },
-                    { name: 'functionSignature', type: 'bytes' },
-                ],
-            };
-
-            const message = {
-                // Has been validated to be defined when function called is `transferWithApproval`
-                nonce: /** @type {{ tokenNonce: number }} */ (request.approval).tokenNonce,
-                from: request.request.from,
-                functionSignature,
-            };
-
-            const signature = await polygonKey.signTypedData(
+            const { sigR, sigS, sigV } = await polygonKey.signUsdcApproval(
                 request.keyPath,
-                domain,
-                types,
-                message,
+                new ethers.Contract(
+                    CONFIG.USDC_CONTRACT_ADDRESS,
+                    PolygonContractABIs.USDC_CONTRACT_ABI,
+                ),
+                CONFIG.USDC_TRANSFER_CONTRACT_ADDRESS,
+                request.description.args.approval,
+                // Has been validated to be defined when function called is `transferWithApproval`
+                /** @type {{ tokenNonce: number }} */ (request.approval).tokenNonce,
+                request.request.from,
             );
 
-            const signerAddress = ethers.utils.verifyTypedData(domain, types, message, signature);
-            if (signerAddress !== request.request.from) {
-                reject(new Errors.CoreError('Failed to sign approval'));
-                return;
-            }
-
-            const sigR = signature.slice(0, 66); // 0x prefix plus 32 bytes = 66 characters
-            const sigS = `0x${signature.slice(66, 130)}`; // 32 bytes = 64 characters
-            const sigV = parseInt(signature.slice(130, 132), 16); // last byte = 2 characters
-
             const usdcTransfer = new ethers.Contract(
                 CONFIG.USDC_TRANSFER_CONTRACT_ADDRESS,
                 PolygonContractABIs.USDC_TRANSFER_CONTRACT_ABI,

diff --git a/src/request/sign-swap/SignSwap.js b/src/request/sign-swap/SignSwap.js
@@ -546,57 +546,19 @@ class SignSwap {
 
         if (request.fund.type === 'USDC') {
             if (request.fund.description.name === 'openWithApproval') {
-                // Sign approval
-                const usdcContract = new ethers.Contract(
-                    CONFIG.USDC_CONTRACT_ADDRESS,
-                    PolygonContractABIs.USDC_CONTRACT_ABI,
-                );
-
-                const functionSignature = usdcContract.interface.encodeFunctionData(
-                    'approve',
-                    [CONFIG.USDC_HTLC_CONTRACT_ADDRESS, request.fund.description.args.approval],
-                );
-
-                // TODO: Make the domain parameters configurable in the request?
-                const domain = {
-                    name: 'USD Coin (PoS)', // This is currently the same for testnet and mainnet
-                    version: '1', // This is currently the same for testnet and mainnet
-                    verifyingContract: CONFIG.USDC_CONTRACT_ADDRESS,
-                    salt: ethers.utils.hexZeroPad(ethers.utils.hexlify(CONFIG.POLYGON_CHAIN_ID), 32),
-                };
-
-                const types = {
-                    MetaTransaction: [
-                        { name: 'nonce', type: 'uint256' },
-                        { name: 'from', type: 'address' },
-                        { name: 'functionSignature', type: 'bytes' },
-                    ],
-                };
-
-                const message = {
-                    // Has been validated to be defined when function called is `openWithApproval`
-                    nonce: /** @type {{ tokenNonce: number }} */ (request.fund.approval).tokenNonce,
-                    from: request.fund.request.from,
-                    functionSignature,
-                };
-
-                const signature = await polygonKey.signTypedData(
+                const { sigR, sigS, sigV } = await polygonKey.signUsdcApproval(
                     request.fund.keyPath,
-                    domain,
-                    types,
-                    message,
+                    new ethers.Contract(
+                        CONFIG.USDC_CONTRACT_ADDRESS,
+                        PolygonContractABIs.USDC_CONTRACT_ABI,
+                    ),
+                    CONFIG.USDC_HTLC_CONTRACT_ADDRESS,
+                    request.fund.description.args.approval,
+                    // Has been validated to be defined when function called is `openWithApproval`
+                    /** @type {{ tokenNonce: number }} */ (request.fund.approval).tokenNonce,
+                    request.fund.request.from,
                 );
 
-                const signerAddress = ethers.utils.verifyTypedData(domain, types, message, signature);
-                if (signerAddress !== request.fund.request.from) {
-                    reject(new Errors.CoreError('Failed to sign approval'));
-                    return;
-                }
-
-                const sigR = signature.slice(0, 66); // 0x prefix plus 32 bytes = 66 characters
-                const sigS = `0x${signature.slice(66, 130)}`; // 32 bytes = 64 characters
-                const sigV = parseInt(signature.slice(130, 132), 16); // last byte = 2 characters
-
                 const htlcContract = new ethers.Contract(
                     CONFIG.USDC_HTLC_CONTRACT_ADDRESS,
                     PolygonContractABIs.USDC_HTLC_CONTRACT_ABI,