Implement NpdmVerificationFileSystem

src/LibHac/Fs/ReadOnlyFileSystem.cs

@@ -76,9 +76,9 @@ public class ReadOnlyFileSystem : IFileSystem
 {
     private SharedRef<IFileSystem> _baseFileSystem;
 
-    public ReadOnlyFileSystem(ref SharedRef<IFileSystem> baseFileSystem)
+    public ReadOnlyFileSystem(ref readonly SharedRef<IFileSystem> baseFileSystem)
     {
-        _baseFileSystem = SharedRef<IFileSystem>.CreateMove(ref baseFileSystem);
+        _baseFileSystem = SharedRef<IFileSystem>.CreateCopy(in baseFileSystem);
 
         Assert.SdkRequires(_baseFileSystem.HasValue);
     }

src/LibHac/FsSrv/Impl/NpdmVerificationFileSystem.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Runtime.CompilerServices;
 using LibHac.Common;
+using LibHac.Crypto;
 using LibHac.Fs;
 using LibHac.Fs.Fsa;
 
@@ -12,14 +13,20 @@ public struct NpdmHash
     private byte _data;
 }
 
+/// <summary>
+/// Wraps an <see cref="IFile"/>. When reading, calculates a hash of the entire file and compares it to the file's
+/// original hash to ensure the file hasn't been modified.
+/// </summary>
+/// <remarks>Based on nnSdk 17.5.0 (FS 17.0.0)</remarks>
 public class NpdmVerificationFile : IFile
 {
-    private NpdmHash _hash;
+    private readonly NpdmHash _hash;
     private UniqueRef<IFile> _baseFile;
 
     public NpdmVerificationFile(ref UniqueRef<IFile> baseFile, NpdmHash hash)
     {
-        throw new NotImplementedException();
+        _hash = hash;
+        _baseFile = UniqueRef<IFile>.Create(ref baseFile);
     }
 
     public override void Dispose()
@@ -30,143 +37,143 @@ public class NpdmVerificationFile : IFile
 
     protected override Result DoRead(out long bytesRead, long offset, Span<byte> destination, in ReadOption option)
     {
-        throw new NotImplementedException();
+        UnsafeHelpers.SkipParamInit(out bytesRead);
+
+        Result res = DryRead(out long readableSize, offset, destination.Length, in option, OpenMode.Read);
+        if (res.IsFailure()) return res.Miss();
+
+        byte[] hashData;
+        byte[] npdmData = null;
+
+        res = ReadAndCalculateNpdmHash();
+        if (res.IsFailure()) return res.Miss();
+
+        if (!CryptoUtil.IsSameBytes(hashData.AsSpan(), _hash, Unsafe.SizeOf<NpdmHash>()))
+            return ResultFs.InvalidNspdVerificationData.Log();
+
+        npdmData.AsSpan((int)offset, (int)readableSize).CopyTo(destination);
+        return Result.Success;
+
+        Result ReadAndCalculateNpdmHash()
+        {
+            hashData = new byte[0x20];
+            Result res2 = _baseFile.Get.GetSize(out long npdmDataSize);
+            if (res2.IsFailure()) return res2.Miss();
+
+            npdmData = new byte[npdmDataSize];
+            res2 = _baseFile.Get.Read(out long npdmReadSize, 0, npdmData, ReadOption.None);
+            if (res2.IsFailure()) return res2.Miss();
+
+            Sha256.GenerateSha256Hash(npdmData.AsSpan(0, (int)npdmReadSize), hashData);
+            return Result.Success;
+        }
     }
 
-    protected override Result DoWrite(long offset, ReadOnlySpan<byte> source, in WriteOption option)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoWrite(long offset, ReadOnlySpan<byte> source, in WriteOption option) =>
+        _baseFile.Get.Write(offset, source, in option).Ret();
 
-    protected override Result DoFlush()
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoFlush() => _baseFile.Get.Flush().Ret();
+    protected override Result DoSetSize(long size) => _baseFile.Get.SetSize(size).Ret();
+    protected override Result DoGetSize(out long size) => _baseFile.Get.GetSize(out size).Ret();
 
-    protected override Result DoSetSize(long size)
-    {
-        throw new NotImplementedException();
-    }
-
-    protected override Result DoGetSize(out long size)
-    {
-        throw new NotImplementedException();
-    }
-
-    protected override Result DoOperateRange(Span<byte> outBuffer, OperationId operationId, long offset, long size, ReadOnlySpan<byte> inBuffer)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoOperateRange(Span<byte> outBuffer, OperationId operationId, long offset, long size,
+        ReadOnlySpan<byte> inBuffer) =>
+        _baseFile.Get.OperateRange(outBuffer, operationId, offset, size, inBuffer).Ret();
 }
 
+/// <summary>
+/// Wraps a code <see cref="IFileSystem"/>. Contains the hash of the code filesystem's .npdm file. When opening the npdm
+/// file, a <see cref="NpdmVerificationFile"/> is used to ensure that the npdm file hasn't been modified.
+/// </summary>
+/// <remarks>Based on nnSdk 17.5.0 (FS 17.0.0)</remarks>
 public class NpdmVerificationFileSystem : IFileSystem
 {
-    private NpdmHash _hash;
-    private ReadOnlyFileSystem _baseFileSystem;
+    private static ReadOnlySpan<byte> NpdmFilePath => "/main.npdm"u8;
 
-    public NpdmVerificationFileSystem(in SharedRef<IFileSystem> baseFileSystem, NpdmHash hash)
+    private readonly NpdmHash _hash;
+    private readonly ReadOnlyFileSystem _baseFileSystem;
+
+    public NpdmVerificationFileSystem(ref readonly SharedRef<IFileSystem> baseFileSystem, NpdmHash hash)
     {
-        
+        _hash = hash;
+        _baseFileSystem = new ReadOnlyFileSystem(in baseFileSystem);
     }
 
     public override void Dispose()
     {
-        _baseFileSystem.Dispose();
+        _baseFileSystem?.Dispose();
         base.Dispose();
     }
 
     protected override Result DoOpenFile(ref UniqueRef<IFile> outFile, ref readonly Path path, OpenMode mode)
     {
-        throw new NotImplementedException();
+        using var file = new UniqueRef<IFile>();
+        Result res = _baseFileSystem.OpenFile(ref file.Ref, in path, mode);
+        if (res.IsFailure()) return res.Miss();
+
+        if (path != NpdmFilePath)
+        {
+            outFile.Set(ref file.Ref);
+            return Result.Success;
+        }
+
+        using var npdmFile = new UniqueRef<IFile>(new NpdmVerificationFile(ref file.Ref, _hash));
+
+        outFile.Set(ref npdmFile.Ref);
+        return Result.Success;
     }
 
-    protected override Result DoCreateFile(ref readonly Path path, long size, CreateFileOptions option)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoCreateFile(ref readonly Path path, long size, CreateFileOptions option) =>
+        _baseFileSystem.CreateFile(in path, size, option).Ret();
 
-    protected override Result DoDeleteFile(ref readonly Path path)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoDeleteFile(ref readonly Path path) =>
+        _baseFileSystem.DeleteFile(in path).Ret();
 
-    protected override Result DoCreateDirectory(ref readonly Path path)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoCreateDirectory(ref readonly Path path) =>
+        _baseFileSystem.CreateDirectory(in path).Ret();
 
-    protected override Result DoDeleteDirectory(ref readonly Path path)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoDeleteDirectory(ref readonly Path path) =>
+        _baseFileSystem.DeleteDirectory(in path).Ret();
 
-    protected override Result DoDeleteDirectoryRecursively(ref readonly Path path)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoDeleteDirectoryRecursively(ref readonly Path path) =>
+        _baseFileSystem.DeleteDirectoryRecursively(in path).Ret();
 
-    protected override Result DoCleanDirectoryRecursively(ref readonly Path path)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoCleanDirectoryRecursively(ref readonly Path path) =>
+        _baseFileSystem.CleanDirectoryRecursively(in path).Ret();
 
-    protected override Result DoRenameFile(ref readonly Path currentPath, ref readonly Path newPath)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoRenameFile(ref readonly Path currentPath, ref readonly Path newPath) =>
+        _baseFileSystem.RenameFile(in currentPath, in newPath).Ret();
 
-    protected override Result DoRenameDirectory(ref readonly Path currentPath, ref readonly Path newPath)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoRenameDirectory(ref readonly Path currentPath, ref readonly Path newPath) =>
+        _baseFileSystem.RenameDirectory(in currentPath, in newPath).Ret();
 
-    protected override Result DoGetEntryType(out DirectoryEntryType entryType, ref readonly Path path)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoGetEntryType(out DirectoryEntryType entryType, ref readonly Path path) =>
+        _baseFileSystem.GetEntryType(out entryType, in path).Ret();
 
-    protected override Result DoGetFreeSpaceSize(out long freeSpace, ref readonly Path path)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoGetFreeSpaceSize(out long freeSpace, ref readonly Path path) =>
+        _baseFileSystem.GetFreeSpaceSize(out freeSpace, in path).Ret();
 
-    protected override Result DoGetTotalSpaceSize(out long totalSpace, ref readonly Path path)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoGetTotalSpaceSize(out long totalSpace, ref readonly Path path) =>
+        _baseFileSystem.GetFreeSpaceSize(out totalSpace, in path).Ret();
 
-    protected override Result DoOpenDirectory(ref UniqueRef<IDirectory> outDirectory, ref readonly Path path, OpenDirectoryMode mode)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoOpenDirectory(ref UniqueRef<IDirectory> outDirectory, ref readonly Path path, OpenDirectoryMode mode) =>
+        _baseFileSystem.OpenDirectory(ref outDirectory, in path, mode).Ret();
 
-    protected override Result DoCommit()
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoCommit() =>
+        _baseFileSystem.Commit().Ret();
 
-    protected override Result DoCommitProvisionally(long counter)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoCommitProvisionally(long counter) =>
+        _baseFileSystem.CommitProvisionally(counter).Ret();
 
-    protected override Result DoRollback()
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoRollback() =>
+        _baseFileSystem.Rollback().Ret();
 
-    protected override Result DoFlush()
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoFlush() =>
+        _baseFileSystem.Flush().Ret();
 
-    protected override Result DoGetFileTimeStampRaw(out FileTimeStampRaw timeStamp, ref readonly Path path)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoGetFileTimeStampRaw(out FileTimeStampRaw timeStamp, ref readonly Path path) =>
+        _baseFileSystem.GetFileTimeStampRaw(out timeStamp, in path).Ret();
 
-    protected override Result DoQueryEntry(Span<byte> outBuffer, ReadOnlySpan<byte> inBuffer, QueryId queryId, ref readonly Path path)
-    {
-        throw new NotImplementedException();
-    }
+    protected override Result DoQueryEntry(Span<byte> outBuffer, ReadOnlySpan<byte> inBuffer, QueryId queryId, ref readonly Path path) =>
+        _baseFileSystem.QueryEntry(outBuffer, inBuffer, queryId, in path).Ret();
 }

src/LibHac/FsSrv/NcaFileSystemServiceImpl.cs

@@ -312,7 +312,7 @@ public class NcaFileSystemServiceImpl : IDisposable
                 res = ParseDirWithPathCaseNormalizationOnCaseSensitiveHostOrLocalFs(ref hostFileSystem.Ref, in directoryPath, mountInfo.FsType);
                 if (res.IsFailure()) return res.Miss();
 
-                using var readOnlyFileSystem = new SharedRef<IFileSystem>(new ReadOnlyFileSystem(ref hostFileSystem.Ref));
+                using var readOnlyFileSystem = new SharedRef<IFileSystem>(new ReadOnlyFileSystem(in hostFileSystem));
                 outFileSystem.SetByMove(ref readOnlyFileSystem.Ref);
 
                 return Result.Success;
@@ -444,7 +444,7 @@ public class NcaFileSystemServiceImpl : IDisposable
             res = ParseDirWithPathCaseNormalizationOnCaseSensitiveHostOrLocalFs(ref hostFileSystem.Ref, in directoryPath, mountInfo.FsType);
             if (res.IsFailure()) return res.Miss();
 
-            using var readOnlyFileSystem = new SharedRef<ReadOnlyFileSystem>(new ReadOnlyFileSystem(ref hostFileSystem.Ref));
+            using var readOnlyFileSystem = new SharedRef<ReadOnlyFileSystem>(new ReadOnlyFileSystem(in hostFileSystem));
 
             outFileSystem.SetByMove(ref readOnlyFileSystem.Ref);
             return Result.Success;

src/LibHac/FsSrv/SaveDataFileSystemServiceImpl.cs

@@ -321,7 +321,7 @@ public class SaveDataFileSystemServiceImpl : IDisposable
         if (openReadOnly)
         {
             using SharedRef<IFileSystem> tempFs = SharedRef<IFileSystem>.CreateMove(ref registerFs.Ref);
-            using var readOnlyFileSystem = new SharedRef<ReadOnlyFileSystem>(new ReadOnlyFileSystem(ref tempFs.Ref));
+            using var readOnlyFileSystem = new SharedRef<ReadOnlyFileSystem>(new ReadOnlyFileSystem(in tempFs));
 
             if (!readOnlyFileSystem.HasValue)
                 return ResultFs.AllocationMemoryFailedInSaveDataFileSystemServiceImplB.Log();