Fix #4744: Add checksum validation for send token address. (#5275)

BraveWallet/Crypto/BuySendSwap/SendTokenView.swift

@@ -37,7 +37,7 @@ struct SendTokenView: View {
     return sendAmount == 0
       || sendAmount > balance
       || sendTokenStore.sendAmount.isEmpty
-      || sendTokenStore.addressError != nil
+      || (sendTokenStore.addressError != nil && sendTokenStore.addressError != .missingChecksum)
   }
 
   var body: some View {

BraveWallet/Crypto/Stores/SendTokenStore.swift

@@ -42,6 +42,8 @@ public class SendTokenStore: ObservableObject {
     case sameAsFromAddress
     case contractAddress
     case notEthAddress
+    case missingChecksum
+    case invalidChecksum
 
     var errorDescription: String? {
       switch self {
@@ -51,6 +53,10 @@ public class SendTokenStore: ObservableObject {
         return Strings.Wallet.sendWarningAddressIsContract
       case .notEthAddress:
         return Strings.Wallet.sendWarningAddressNotValid
+      case .missingChecksum:
+        return Strings.Wallet.sendWarningAddressMissingChecksumInfo
+      case .invalidChecksum:
+        return Strings.Wallet.sendWarningAddressInvalidChecksum
       }
     }
   }
@@ -178,14 +184,29 @@ public class SendTokenStore: ObservableObject {
     }
     let normalizedSendAddress = sendAddress.lowercased()
     if !sendAddress.isETHAddress {
+      // 1. check if send address is a valid eth address
       addressError = .notEthAddress
     } else if currentAccountAddress?.lowercased() == normalizedSendAddress {
+      // 2. check if send address is the same as the from address
       addressError = .sameAsFromAddress
     } else if (userAssets.first(where: { $0.contractAddress.lowercased() == normalizedSendAddress }) != nil)
       || (allTokens.first(where: { $0.contractAddress.lowercased() == normalizedSendAddress }) != nil) {
+      // 3. check if send address is a contract address
       addressError = .contractAddress
     } else {
-      addressError = nil
+      keyringService.checksumEthAddress(sendAddress) { [self] checksumAddress in
+        if sendAddress == checksumAddress {
+          // 4. check if send address is the same as the checksum address from the `KeyringService`
+          addressError = nil
+        } else if sendAddress.removingHexPrefix.lowercased() == sendAddress.removingHexPrefix || sendAddress.removingHexPrefix.uppercased() == sendAddress.removingHexPrefix {
+          // 5. check if send address has each of the alphabetic character as uppercase, or has each of
+          // the alphabeic character as lowercase
+          addressError = .missingChecksum
+        } else {
+          // 6. send address has mixed with uppercase and lowercase and does not match with the checksum address
+          addressError = .invalidChecksum
+        }
+      }
     }
   }
 

BraveWallet/WalletStrings.swift

@@ -1597,6 +1597,20 @@ extension Strings {
       value: "Not a valid ETH address",
       comment: "A warning that appears below the send crypto address text field, when the input `To` address is not a valid ETH address."
     )
+    public static let sendWarningAddressMissingChecksumInfo = NSLocalizedString(
+      "wallet.sendWarningAddressMissingChecksumInfo",
+      tableName: "BraveWallet",
+      bundle: .braveWallet,
+      value: "This address cannot be verified (missing checksum). Proceed?",
+      comment: "A warning that appears below the send crypto address text field, when the input `To` address is missing checksum information."
+    )
+    public static let sendWarningAddressInvalidChecksum = NSLocalizedString(
+      "wallet.sendWarningAddressInvalidChecksum",
+      tableName: "BraveWallet",
+      bundle: .braveWallet,
+      value: "Address did not pass verification (invalid checksum). Please try again, replacing lowercase letters with uppercase.",
+      comment: "A warning that appears below the send crypto address text field, when the input `To` address has invalid checksum."
+    )
     public static let betaLabel = NSLocalizedString(
       "wallet.betaLabel",
       tableName: "BraveWallet",