Validates melonDS BIOS files

Compares file sizes and MD5 hashes (when relevant) to ensure BIOS files are correct.

Delta.xcodeproj/project.pbxproj

@@ -22,6 +22,7 @@
 
 /* Begin PBXBuildFile section */
 		1FA4ABA79AB72914FE414A61 /* libPods-Delta.a in Frameworks */ = {isa = PBXBuildFile; fileRef = DC866E433B3BA9AE18ABA1EC /* libPods-Delta.a */; };
+		BF00BEA625B758AA00C8607D /* SystemBIOS.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF00BEA525B758AA00C8607D /* SystemBIOS.swift */; };
 		BF02D5DA1DDEBB3000A5E131 /* openvgdb.sqlite in Resources */ = {isa = PBXBuildFile; fileRef = BF02D5D91DDEBB3000A5E131 /* openvgdb.sqlite */; };
 		BF04E6FF1DB8625C000F35D3 /* ControllerSkinsViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF04E6FE1DB8625C000F35D3 /* ControllerSkinsViewController.swift */; };
 		BF1020E31F95B05B00313182 /* DeltaToDelta2.xcmappingmodel in Sources */ = {isa = PBXBuildFile; fileRef = BF1020E21F95B05B00313182 /* DeltaToDelta2.xcmappingmodel */; };
@@ -157,6 +158,7 @@
 /* Begin PBXFileReference section */
 		22506DA00971C4300AF90A35 /* Pods.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = Pods.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		A19FF50F55441BC2B2248241 /* Pods-Delta.release.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Delta.release.xcconfig"; path = "Pods/Target Support Files/Pods-Delta/Pods-Delta.release.xcconfig"; sourceTree = "<group>"; };
+		BF00BEA525B758AA00C8607D /* SystemBIOS.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SystemBIOS.swift; sourceTree = "<group>"; };
 		BF02D5D91DDEBB3000A5E131 /* openvgdb.sqlite */ = {isa = PBXFileReference; lastKnownFileType = file; path = openvgdb.sqlite; sourceTree = "<group>"; };
 		BF0418131D01E93400E85BCF /* GBADeltaCore.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = GBADeltaCore.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		BF04E6FE1DB8625C000F35D3 /* ControllerSkinsViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ControllerSkinsViewController.swift; sourceTree = "<group>"; };
@@ -718,6 +720,7 @@
 			isa = PBXGroup;
 			children = (
 				BFE9907F24451E15006409A7 /* MelonDSCoreSettingsViewController.swift */,
+				BF00BEA525B758AA00C8607D /* SystemBIOS.swift */,
 			);
 			path = Cores;
 			sourceTree = "<group>";
@@ -1142,6 +1145,7 @@
 				BF6BF3271EB87EB8008E83CD /* PhotoLibraryImportOption.swift in Sources */,
 				BF5942661E09BBB10051894B /* LoadImageURLOperation.swift in Sources */,
 				BF353FF21C5D7FB000C1184C /* PauseViewController.swift in Sources */,
+				BF00BEA625B758AA00C8607D /* SystemBIOS.swift in Sources */,
 				BF696B801D9B2B02009639E0 /* Theme.swift in Sources */,
 				BF7AE8081C2E858400B1B5BC /* GridMenuViewController.swift in Sources */,
 				BF6BF31A1EB82146008E83CD /* ClipboardImportOption.swift in Sources */,

Delta/Settings/Cores/MelonDSCoreSettingsViewController.swift

@@ -9,6 +9,7 @@
 import UIKit
 import SafariServices
 import MobileCoreServices
+import CryptoKit
 
 import DeltaCore
 import MelonDSDeltaCore
@@ -27,44 +28,77 @@ private extension MelonDSCoreSettingsViewController
         case changeCore
     }
     
-    enum DSBIOS: Int
+    enum BIOSError: LocalizedError
     {
-        case bios7
+        case unknownSize(URL)
-        case bios9
+        case incorrectHash(URL, hash: String, expectedHash: String)
-        case firmware
         
-        var fileURL: URL {
+        @available(iOS 13, *)
+        case incorrectSize(URL, size: Int, validSizes: Set<ClosedRange<Measurement<UnitInformationStorage>>>)
+                
+        private static let byteFormatter: ByteCountFormatter = {
+            let formatter = ByteCountFormatter()
+            formatter.includesActualByteCount = true
+            formatter.countStyle = .binary
+            return formatter
+        }()
+        
+        var errorDescription: String? {
             switch self
             {
-            case .bios7: return MelonDSEmulatorBridge.shared.bios7URL
+            case .unknownSize(let fileURL):
-            case .bios9: return MelonDSEmulatorBridge.shared.bios9URL
+                return String(format: NSLocalizedString("%@’s size could not be determined.", comment: ""), fileURL.lastPathComponent)
-            case .firmware: return MelonDSEmulatorBridge.shared.firmwareURL
+                
+            case .incorrectHash(let fileURL, let md5Hash, let expectedHash):
+                return String(format: NSLocalizedString("%@‘s hash does not match the expected hash.\n\nHash:\n%@\n\nExpected:\n%@.", comment: ""), fileURL.lastPathComponent, md5Hash, expectedHash)
+                
+            case .incorrectSize(let fileURL, let size, let validSizes):
+                let actualSize = BIOSError.byteFormatter.string(fromByteCount: Int64(size))
+                
+                if let range = validSizes.first, validSizes.count == 1
+                {
+                    if range.lowerBound == range.upperBound
+                    {
+                        // Single value
+                        let expectedSize = BIOSError.byteFormatter.string(fromByteCount: Int64(range.lowerBound.converted(to: .bytes).value))
+                        return String(format: NSLocalizedString("%@ is %@, but expected size is %@.", comment: ""), fileURL.lastPathComponent, actualSize, expectedSize)
+                    }
+                    else
+                    {
+                        // Range
+                        BIOSError.byteFormatter.includesActualByteCount = false
+                        defer { BIOSError.byteFormatter.includesActualByteCount = true }
+                        
+                        let lowerBound = BIOSError.byteFormatter.string(fromByteCount: Int64(range.lowerBound.converted(to: .bytes).value))
+                        let upperBound = BIOSError.byteFormatter.string(fromByteCount: Int64(range.upperBound.converted(to: .bytes).value))
+                        return String(format: NSLocalizedString("%@ is %@, but expected size is between %@ and %@.", comment: ""), fileURL.lastPathComponent, actualSize, lowerBound, upperBound)
+                    }
+                }
+                else
+                {
+                    var description = String(format: NSLocalizedString("%@ is %@, but expected sizes are:", comment: ""), fileURL.lastPathComponent, actualSize) + "\n"
+                    
+                    let sortedRanges = validSizes.sorted(by: { $0.lowerBound < $1.lowerBound })
+                    for range in sortedRanges
+                    {
+                        // Assume BIOS with multiple valid file sizes don't use (>1 count) ranges.
+                        description += "\n" + BIOSError.byteFormatter.string(fromByteCount: Int64(range.lowerBound.converted(to: .bytes).value))
+                    }
+                    
+                    return description
+                }
             }
         }
-    }
-    
-    enum DSiBIOS: Int
-    {
-        case bios7
-        case bios9
-        case firmware
-        case nand
         
-        var fileURL: URL {
+        var recoverySuggestion: String? {
-            switch self
+            return NSLocalizedString("Please choose a different BIOS file.", comment: "")
-            {
-            case .bios7: return MelonDSEmulatorBridge.shared.dsiBIOS7URL
-            case .bios9: return MelonDSEmulatorBridge.shared.dsiBIOS9URL
-            case .firmware: return MelonDSEmulatorBridge.shared.dsiFirmwareURL
-            case .nand: return MelonDSEmulatorBridge.shared.dsiNANDURL
-            }
         }
     }
 }
 
 class MelonDSCoreSettingsViewController: UITableViewController
 {
-    private var importDestinationURL: URL?
+    private var importingBIOS: SystemBIOS?
     
     override func viewDidLoad()
     {
@@ -121,9 +155,9 @@ private extension MelonDSCoreSettingsViewController
         self.present(safariViewController, animated: true, completion: nil)
     }
     
-    func locateBIOS(for destinationURL: URL)
+    func locate<BIOS: SystemBIOS>(_ bios: BIOS)
     {
-        self.importDestinationURL = destinationURL
+        self.importingBIOS = bios
         
         var supportedTypes = [kUTTypeItem as String, kUTTypeContent as String, "com.apple.macbinary-archive" /* System UTI for .bin */]
         
@@ -220,7 +254,7 @@ extension MelonDSCoreSettingsViewController
             cell.contentView.isHidden = (item == nil)
             
         case .dsBIOS:
-            let bios = DSBIOS(rawValue: indexPath.row)!
+            let bios = DSBIOS.allCases[indexPath.row]
             
             if FileManager.default.fileExists(atPath: bios.fileURL.path)
             {
@@ -238,7 +272,7 @@ extension MelonDSCoreSettingsViewController
             cell.selectionStyle = .default
             
         case .dsiBIOS:
-            let bios = DSiBIOS(rawValue: indexPath.row)!
+            let bios = DSiBIOS.allCases[indexPath.row]
             
             if FileManager.default.fileExists(atPath: bios.fileURL.path)
             {
@@ -288,12 +322,12 @@ extension MelonDSCoreSettingsViewController
             self.openMetadataURL(for: key)
             
         case .dsBIOS:
-            let bios = DSBIOS(rawValue: indexPath.row)!
+            let bios = DSBIOS.allCases[indexPath.row]
-            self.locateBIOS(for: bios.fileURL)
+            self.locate(bios)
             
         case .dsiBIOS:
-            let bios = DSiBIOS(rawValue: indexPath.row)!
+            let bios = DSiBIOS.allCases[indexPath.row]
-            self.locateBIOS(for: bios.fileURL)
+            self.locate(bios)
             
         case .changeCore:
             self.changeCore()
@@ -374,28 +408,58 @@ extension MelonDSCoreSettingsViewController: UIDocumentPickerDelegate
 {
     func documentPickerWasCancelled(_ controller: UIDocumentPickerViewController)
     {
-        self.importDestinationURL = nil
+        self.importingBIOS = nil
         self.tableView.reloadData() // Reloading index path causes cell to disappear...
     }
     
     func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL])
     {
         defer {
-            self.importDestinationURL = nil
+            self.importingBIOS = nil
             self.tableView.reloadData() // Reloading index path causes cell to disappear...
         }
         
-        guard let fileURL = urls.first, let destinationURL = self.importDestinationURL else { return }
+        guard let fileURL = urls.first, let bios = self.importingBIOS else { return }
+        
+        defer { try? FileManager.default.removeItem(at: fileURL) }
         
         do
         {
-            try FileManager.default.copyItem(at: fileURL, to: destinationURL, shouldReplace: true)
+            if #available(iOS 13.0, *)
+            {
+                // Validate file size first (since that's easiest for users to understand).
+                
+                let attributes = try FileManager.default.attributesOfItem(atPath: fileURL.path)
+                guard let fileSize = attributes[.size] as? Int else { throw BIOSError.unknownSize(fileURL) }
+                
+                let measurement = Measurement<UnitInformationStorage>(value: Double(fileSize), unit: .bytes)
+                guard bios.validFileSizes.contains(where: { $0.contains(measurement) }) else { throw BIOSError.incorrectSize(fileURL, size: fileSize, validSizes: bios.validFileSizes) }
+                
+                if let expectedMD5Hash = bios.expectedMD5Hash
+                {
+                    // If there's an expected hash, make sure it matches.
+                    
+                    let data = try Data(contentsOf: fileURL)
+                    
+                    let md5Hash = Insecure.MD5.hash(data: data)
+                    let hashString = md5Hash.compactMap { String(format: "%02x", $0) }.joined()
+                    guard hashString == expectedMD5Hash else { throw BIOSError.incorrectHash(fileURL, hash: hashString, expectedHash: expectedMD5Hash) }
+                }
+            }
+            
+            try FileManager.default.copyItem(at: fileURL, to: bios.fileURL, shouldReplace: true)
         }
-        catch
+        catch let error as NSError
         {
-            let title = String(format: NSLocalizedString("Could not import %@.", comment: ""), fileURL.lastPathComponent)
+            let title = String(format: NSLocalizedString("Could not import %@.", comment: ""), bios.filename)
 
-            let alertController = UIAlertController(title: title, message: error.localizedDescription, preferredStyle: .alert)
+            var message = error.localizedDescription
+            if let recoverySuggestion = error.localizedRecoverySuggestion
+            {
+                message += "\n\n" + recoverySuggestion
+            }
+            
+            let alertController = UIAlertController(title: title, message: message, preferredStyle: .alert)
             alertController.addAction(.ok)
             self.present(alertController, animated: true, completion: nil)
         }

Delta/Settings/Cores/SystemBIOS.swift

@@ -0,0 +1,123 @@
+//
+//  SystemBIOS.swift
+//  Delta
+//
+//  Created by Riley Testut on 1/19/21.
+//  Copyright © 2021 Riley Testut. All rights reserved.
+//
+
+import Foundation
+
+import MelonDSDeltaCore
+
+protocol SystemBIOS
+{
+    var fileURL: URL { get }
+    var filename: String { get }
+    
+    var expectedMD5Hash: String? { get }
+    
+    // RangeSet would be preferable, but it's not in Swift stdlib yet.
+    @available(iOS 13, *)
+    var validFileSizes: Set<ClosedRange<Measurement<UnitInformationStorage>>> { get }
+}
+
+extension SystemBIOS
+{
+    var filename: String {
+        return self.fileURL.lastPathComponent
+    }
+}
+
+enum DSBIOS: SystemBIOS, CaseIterable
+{
+    case bios7
+    case bios9
+    case firmware
+    
+    var fileURL: URL {
+        switch self
+        {
+        case .bios7: return MelonDSEmulatorBridge.shared.bios7URL
+        case .bios9: return MelonDSEmulatorBridge.shared.bios9URL
+        case .firmware: return MelonDSEmulatorBridge.shared.firmwareURL
+        }
+    }
+    
+    var expectedMD5Hash: String? {
+        switch self
+        {
+        case .bios7: return "df692a80a5b1bc90728bc3dfc76cd948"
+        case .bios9: return "a392174eb3e572fed6447e956bde4b25"
+        case .firmware: return nil
+        }
+    }
+    
+    @available(iOS 13, *)
+    var validFileSizes: Set<ClosedRange<Measurement<UnitInformationStorage>>> {
+        // From http://melonds.kuribo64.net/faq.php
+        switch self
+        {
+        case .bios7:
+            // 16KB
+            return Set([16].map { Measurement(value: $0, unit: .kibibytes) }.map { $0...$0 })
+        case .bios9:
+            // 4KB
+            return Set([4].map { Measurement(value: $0, unit: .kibibytes) }.map { $0...$0 })
+        case .firmware:
+            // 128KB, 256KB, or 512KB
+            return Set([128, 256, 512].map { Measurement(value: $0, unit: .kibibytes) }.map { $0...$0 })
+        }
+    }
+}
+
+enum DSiBIOS: SystemBIOS, CaseIterable
+{
+    case bios7
+    case bios9
+    case firmware
+    case nand
+    
+    var fileURL: URL {
+        switch self
+        {
+        case .bios7: return MelonDSEmulatorBridge.shared.dsiBIOS7URL
+        case .bios9: return MelonDSEmulatorBridge.shared.dsiBIOS9URL
+        case .firmware: return MelonDSEmulatorBridge.shared.dsiFirmwareURL
+        case .nand: return MelonDSEmulatorBridge.shared.dsiNANDURL
+        }
+    }
+    
+    var expectedMD5Hash: String? {
+        switch self
+        {
+        case .bios7: return "559dae4ea78eb9d67702c56c1d791e81"
+        case .bios9: return "87b665fce118f76251271c3732532777"
+        case .firmware: return nil
+        case .nand: return nil
+        }
+    }
+    
+    @available(iOS 13, *)
+    var validFileSizes: Set<ClosedRange<Measurement<UnitInformationStorage>>> {
+        // From http://melonds.kuribo64.net/faq.php
+        switch self
+        {
+        case .bios7:
+            // 64KB
+            return Set([64].map { Measurement(value: $0, unit: .kibibytes) }.map { $0...$0 })
+            
+        case .bios9:
+            // 64KB
+            return Set([64].map { Measurement(value: $0, unit: .kibibytes) }.map { $0...$0 })
+            
+        case .firmware:
+            // 128KB
+            return Set([128].map { Measurement(value: $0, unit: .kibibytes) }.map { $0...$0 })
+            
+        case .nand:
+            // 200MB - 300MB
+            return Set([200...300].map { Measurement(value: $0.lowerBound, unit: .mebibytes) ... Measurement(value: $0.upperBound, unit: .mebibytes) })
+        }
+    }
+}