Add save file integrity verification

LibHac/HierarchicalIntegrityVerificationStream.cs

@@ -19,8 +19,7 @@ namespace LibHac
 
             for (int i = 1; i < Levels.Length; i++)
             {
-                var levelData = new IntegrityVerificationStream(levelInfo[i].Data, Levels[i - 1],
+                var levelData = new IntegrityVerificationStream(levelInfo[i], Levels[i - 1], enableIntegrityChecks);
-                    levelInfo[i].BlockSizePower, enableIntegrityChecks);
 
                 Levels[i] = new RandomAccessSectorStream(levelData);
             }

LibHac/IntegrityVerificationStream.cs

@@ -12,14 +12,19 @@ namespace LibHac
         private Stream HashStream { get; }
         public bool EnableIntegrityChecks { get; }
 
+        private byte[] Salt { get; }
+        private IntegrityStreamType Type { get; }
+
         private readonly byte[] _hashBuffer = new byte[DigestSize];
         private readonly SHA256 _hash = SHA256.Create();
 
-        public IntegrityVerificationStream(Stream dataStream, Stream hashStream, int blockSizePower, bool enableIntegrityChecks)
+        public IntegrityVerificationStream(IntegrityVerificationInfo info, Stream hashStream, bool enableIntegrityChecks)
-            : base(dataStream, 1 << blockSizePower)
+            : base(info.Data, 1 << info.BlockSizePower)
         {
             HashStream = hashStream;
             EnableIntegrityChecks = enableIntegrityChecks;
+            Salt = info.Salt;
+            Type = info.Type;
         }
 
         public override void Flush()
@@ -55,21 +60,42 @@ namespace LibHac
             HashStream.Position = CurrentSector * DigestSize;
             HashStream.Read(_hashBuffer, 0, DigestSize);
 
+            int bytesRead = base.Read(buffer, 0, count);
+
             // If a hash is zero the data for the entire block is zero
-            if (_hashBuffer.IsEmpty())
+            if (Type == IntegrityStreamType.Save && _hashBuffer.IsEmpty())
             {
                 Array.Clear(buffer, 0, SectorSize);
+                return bytesRead;
             }
 
-            int bytesRead = base.Read(buffer, 0, count);
-
             if (bytesRead < SectorSize)
             {
                 // Pad out unused portion of block
                 Array.Clear(buffer, bytesRead, SectorSize - bytesRead);
             }
 
-            if (EnableIntegrityChecks && !Util.ArraysEqual(_hashBuffer, _hash.ComputeHash(buffer)))
+            if (!EnableIntegrityChecks) return bytesRead;
+
+            _hash.Initialize();
+
+            if (Type == IntegrityStreamType.Save)
+            {
+                _hash.TransformBlock(Salt, 0, Salt.Length, null, 0);
+            }
+
+            _hash.TransformBlock(buffer, 0, SectorSize, null, 0);
+            _hash.TransformFinalBlock(buffer, 0, 0);
+
+            byte[] hash = _hash.Hash;
+
+            if (Type == IntegrityStreamType.Save)
+            {
+                // This bit is set on all save hashes
+                hash[0x1F] |= 0x80;
+            }
+
+            if (!Util.ArraysEqual(_hashBuffer, hash))
             {
                 throw new InvalidDataException("Hash error!");
             }
@@ -94,5 +120,13 @@ namespace LibHac
     {
         public Stream Data { get; set; }
         public int BlockSizePower { get; set; }
+        public byte[] Salt { get; set; }
+        public IntegrityStreamType Type { get; set; }
+    }
+
+    public enum IntegrityStreamType
+    {
+        Save,
+        RomFs
     }
 }

LibHac/Nca.cs

@@ -167,7 +167,8 @@ namespace LibHac
                 initInfo[i] = new IntegrityVerificationInfo
                 {
                     Data = data,
-                    BlockSizePower = level.BlockSize
+                    BlockSizePower = level.BlockSize,
+                    Type = IntegrityStreamType.RomFs
                 };
             }
 

LibHac/NcaStructs.cs

@@ -166,9 +166,9 @@ namespace LibHac
         public uint MasterHashSize;
         public uint NumLevels;
         public IvfcLevelHeader[] LevelHeaders = new IvfcLevelHeader[6];
+        public byte[] SaltSource;
         public byte[] MasterHash;
 
-
         public IvfcHeader(BinaryReader reader)
         {
             Magic = reader.ReadAscii(4);
@@ -181,7 +181,7 @@ namespace LibHac
                 LevelHeaders[i] = new IvfcLevelHeader(reader);
             }
 
-            reader.BaseStream.Position += 0x20;
+            SaltSource = reader.ReadBytes(0x20);
             MasterHash = reader.ReadBytes(0x20);
         }
     }

LibHac/Savefile/Header.cs

@@ -9,6 +9,7 @@ namespace LibHac.Savefile
         public FsLayout Layout { get; set; }
         public JournalHeader Journal { get; set; }
         public DuplexHeader Duplex { get; set; }
+        public IvfcHeader Ivfc { get; set; }
         public SaveHeader Save { get; set; }
 
         public RemapHeader FileRemap { get; set; }
@@ -41,6 +42,9 @@ namespace LibHac.Savefile
             reader.BaseStream.Position = 0x300;
             Duplex = new DuplexHeader(reader);
 
+            reader.BaseStream.Position = 0x344;
+            Ivfc = new IvfcHeader(reader);
+
             reader.BaseStream.Position = 0x408;
             Journal = new JournalHeader(reader);
 

LibHac/Savefile/Savefile.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.IO;
+using System.Security.Cryptography;
 using System.Text;
 using LibHac.Streams;
 
@@ -15,6 +16,8 @@ namespace LibHac.Savefile
         public SharedStreamSource MetaRemapSource { get; }
         private JournalStream JournalStream { get; }
         public SharedStreamSource JournalStreamSource { get; }
+        private HierarchicalIntegrityVerificationStream IvfcStream { get; }
+        public SharedStreamSource IvfcStreamSource { get; }
         private AllocationTable AllocationTable { get; }
 
         public Stream DuplexL1A { get; }
@@ -38,7 +41,7 @@ namespace LibHac.Savefile
         public DirectoryEntry[] Directories { get; private set; }
         private Dictionary<string, FileEntry> FileDict { get; }
 
-        public Savefile(Keyset keyset, Stream file, IProgressReport logger = null)
+        public Savefile(Keyset keyset, Stream file, bool enableIntegrityChecks, IProgressReport logger = null)
         {
             SavefileSource = new SharedStreamSource(file);
 
@@ -102,6 +105,10 @@ namespace LibHac.Savefile
                     layout.JournalDataSizeB + layout.SizeReservedArea);
                 JournalStream = new JournalStream(journalData, journalMap, (int)Header.Journal.BlockSize);
                 JournalStreamSource = new SharedStreamSource(JournalStream);
+
+                IvfcStream = InitIvfcStream(enableIntegrityChecks);
+                IvfcStreamSource = new SharedStreamSource(IvfcStream);
+
                 ReadFileInfo();
                 Dictionary<string, FileEntry> dictionary = new Dictionary<string, FileEntry>();
                 foreach (FileEntry entry in Files)
@@ -113,6 +120,40 @@ namespace LibHac.Savefile
             }
         }
 
+        private HierarchicalIntegrityVerificationStream InitIvfcStream(bool enableIntegrityChecks)
+        {
+            IvfcHeader ivfc = Header.Ivfc;
+
+            const int ivfcLevels = 5;
+            var initInfo = new IntegrityVerificationInfo[ivfcLevels];
+
+            initInfo[0] = new IntegrityVerificationInfo
+            {
+                Data = new MemoryStream(Header.MasterHashA),
+                BlockSizePower = 0,
+                Type = IntegrityStreamType.Save
+            };
+
+            for (int i = 1; i < ivfcLevels; i++)
+            {
+                IvfcLevelHeader level = ivfc.LevelHeaders[i - 1];
+
+                Stream data = i == ivfcLevels - 1
+                    ? (Stream)JournalStream
+                    : MetaRemapSource.CreateStream(level.LogicalOffset, level.HashDataSize);
+
+                initInfo[i] = new IntegrityVerificationInfo
+                {
+                    Data = data,
+                    BlockSizePower = level.BlockSize,
+                    Salt = new HMACSHA256(Encoding.ASCII.GetBytes(SaltSources[i - 1])).ComputeHash(ivfc.SaltSource),
+                    Type = IntegrityStreamType.Save
+                };
+            }
+
+            return new HierarchicalIntegrityVerificationStream(initInfo, enableIntegrityChecks);
+        }
+
         public Stream OpenFile(string filename)
         {
             if (!FileDict.TryGetValue(filename, out FileEntry file))
@@ -135,7 +176,7 @@ namespace LibHac.Savefile
 
         private AllocationTableStream OpenFatBlock(int blockIndex, long size)
         {
-            return new AllocationTableStream(JournalStreamSource.CreateStream(), AllocationTable, (int)Header.Save.BlockSize, blockIndex, size);
+            return new AllocationTableStream(IvfcStreamSource.CreateStream(), AllocationTable, (int)Header.Save.BlockSize, blockIndex, size);
         }
 
         public bool FileExists(string filename) => FileDict.ContainsKey(filename);
@@ -242,6 +283,16 @@ namespace LibHac.Savefile
 
             return true;
         }
+
+        private string[] SaltSources =
+        {
+            "HierarchicalIntegrityVerificationStorage::Master",
+            "HierarchicalIntegrityVerificationStorage::L1",
+            "HierarchicalIntegrityVerificationStorage::L2",
+            "HierarchicalIntegrityVerificationStorage::L3",
+            "HierarchicalIntegrityVerificationStorage::L4",
+            "HierarchicalIntegrityVerificationStorage::L5"
+        };
     }
 
     public static class SavefileExtensions

LibHac/SwitchFs.cs

@@ -114,7 +114,7 @@ namespace LibHac
 
                     string sdPath = "/" + Util.GetRelativePath(file, SaveDir).Replace('\\', '/');
                     var nax0 = new Nax0(Keyset, stream, sdPath, false);
-                    save = new Savefile.Savefile(Keyset, nax0.Stream);
+                    save = new Savefile.Savefile(Keyset, nax0.Stream, false);
                 }
                 catch (Exception ex)
                 {

NandReader/Program.cs

@@ -102,7 +102,7 @@ namespace NandReader
         private static List<Ticket> ReadTickets(Keyset keyset, Stream savefile)
         {
             var tickets = new List<Ticket>();
-            var save = new Savefile(keyset, savefile);
+            var save = new Savefile(keyset, savefile, false);
             var ticketList = new BinaryReader(save.OpenFile("/ticket_list.bin"));
             var ticketFile = new BinaryReader(save.OpenFile("/ticket.bin"));
 

NandReaderGui/ViewModel/NandViewModel.cs

@@ -84,7 +84,7 @@ namespace NandReaderGui.ViewModel
         private static List<Ticket> ReadTickets(Keyset keyset, Stream savefile)
         {
             var tickets = new List<Ticket>();
-            var save = new Savefile(keyset, savefile);
+            var save = new Savefile(keyset, savefile, false);
             var ticketList = new BinaryReader(save.OpenFile("/ticket_list.bin"));
             var ticketFile = new BinaryReader(save.OpenFile("/ticket.bin"));
 
@@ -100,6 +100,7 @@ namespace NandReaderGui.ViewModel
 
             return tickets;
         }
+
         private static Keyset OpenKeyset()
         {
             var home = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);

hactoolnet/Program.cs

@@ -104,7 +104,7 @@ namespace hactoolnet
         {
             using (var file = new FileStream(ctx.Options.InFile, FileMode.Open, FileAccess.ReadWrite))
             {
-                var save = new Savefile(ctx.Keyset, file, ctx.Logger);
+                var save = new Savefile(ctx.Keyset, file, ctx.Options.EnableHash, ctx.Logger);
 
                 if (ctx.Options.OutDir != null)
                 {
@@ -136,7 +136,7 @@ namespace hactoolnet
                     save.JournalLayer3Hash.WriteAllBytes(Path.Combine(dir, "L2_6_Layer3Hash"), ctx.Logger);
                     save.JournalFat.WriteAllBytes(Path.Combine(dir, "L2_7_FAT"), ctx.Logger);
 
-                    save.JournalStreamSource.CreateStream().WriteAllBytes(Path.Combine(dir, "L3_0_SaveData"), ctx.Logger);
+                    save.IvfcStreamSource.CreateStream().WriteAllBytes(Path.Combine(dir, "L3_0_SaveData"), ctx.Logger);
                 }
 
                 if (ctx.Options.SignSave)