fix bugs and add some placeholders

+ fix file magic number check
+ change marker size 7 -> 8
+ set key field when creating-and-unlocking, so Locked becomes false
+ throw InvalidOperationException in GetRootDirectory when the store is not unlocked
+ invert Locked property (hahaha)
+ fix debug logging in OuterEncryptionReader
+ implement reading the file header from a Stream
+ PassStoreFileAccessor.Unlock reads and prints out the file header (placeholder for future implementation)
+ the Create Store button creates an empty file at the selected location
+ the Open Store button checks the file and calls Unlock

src/KeyKeeper/PasswordStore/Crypto/OuterEncryptionReader.cs

@@ -139,7 +139,7 @@ public class OuterEncryptionReader : Stream
             toRead -= n;
             chunkPosition += n;
             position += n;
-            Console.WriteLine(string.Format("read={} toread={} pos={}", read, toRead, chunkPosition));
+            Console.WriteLine(string.Format("read={0} toread={1} pos={2}", read, toRead, chunkPosition));
         }
         return read;
     }

src/KeyKeeper/PasswordStore/FileFormatConstants.cs

@@ -30,5 +30,5 @@ static class FileFormatConstants
     public const byte GROUP_TYPE_FAVOURITES = 0x02;
     public const byte GROUP_TYPE_SIMPLE = 0x03;
     public const byte GROUP_TYPE_CUSTOM = 0xff; // пока не используется
-    public static readonly byte[] BEGIN_MARKER = [0x5f, 0x4f, 0xcf, 0x67, 0xc0, 0x90, 0xd0];
+    public static readonly byte[] BEGIN_MARKER = [0x5f, 0x4f, 0xcf, 0x67, 0xc0, 0x90, 0xd0, 0xe5];
 }

src/KeyKeeper/PasswordStore/PassStoreFileAccessor.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Security.Cryptography;
 using KeyKeeper.PasswordStore.Crypto;
 using KeyKeeper.PasswordStore.Crypto.KeyDerivation;
@@ -36,11 +37,13 @@ public class PassStoreFileAccessor : IPassStore
 
     public bool Locked
     {
-        get { return key != null; }
+        get { return key == null; }
     }
 
     public IPassStoreDirectory GetRootDirectory()
     {
+        if (Locked)
+            throw new InvalidOperationException();
         return root!;
     }
 
@@ -52,6 +55,10 @@ public class PassStoreFileAccessor : IPassStore
     public void Unlock(CompositeKey key)
     {
         if (!Locked) return;
+
+        using FileStream file = new(filename, FileMode.Open, FileAccess.Read, FileShare.None);
+        FileHeader hdr = FileHeader.ReadFrom(file);
+        Console.WriteLine(hdr); // debug
     }
 
     public void Lock()
@@ -74,7 +81,7 @@ public class PassStoreFileAccessor : IPassStore
         {
             throw PassStoreFileException.UnexpectedEndOfFile;
         }
-        if (magic != FORMAT_MAGIC)
+        if (!magic.SequenceEqual(FORMAT_MAGIC))
         {
             throw PassStoreFileException.IncorrectMagicNumber;
         }
@@ -125,9 +132,9 @@ public class PassStoreFileAccessor : IPassStore
             file.Write(randomPadding);
         }
 
-        byte[] masterKey = newHeader.KdfInfo.GetKdf().Derive(options.Key, 32);
+        key = newHeader.KdfInfo.GetKdf().Derive(options.Key, 32);
         // пока предполагаем что везде используется AES
-        OuterEncryptionWriter cryptoWriter = new(file, masterKey, ((OuterAesHeader)newHeader.OuterCryptoHeader).InitVector);
+        OuterEncryptionWriter cryptoWriter = new(file, key, ((OuterAesHeader)newHeader.OuterCryptoHeader).InitVector);
 
         BinaryWriter wr = new(cryptoWriter);
 
@@ -234,6 +241,70 @@ public class PassStoreFileAccessor : IPassStore
             }
             return written;
         }
+
+        public static FileHeader ReadFrom(Stream s)
+        {
+            BinaryReader rd = new(s);
+            {
+                byte[] magic = new byte[8];
+                if (rd.Read(magic, 0, 8) < 8)
+                    throw PassStoreFileException.UnexpectedEndOfFile;
+                if (!magic.SequenceEqual(FORMAT_MAGIC))
+                    throw PassStoreFileException.IncorrectMagicNumber;
+            }
+            try
+            {
+                ushort major, minor;
+                major = rd.ReadUInt16();
+                minor = rd.ReadUInt16();
+                if (major != FORMAT_VERSION_MAJOR || minor != FORMAT_VERSION_MINOR)
+                    throw PassStoreFileException.UnsupportedVersion;
+
+                byte saltLen = rd.ReadByte();
+                if (saltLen < MIN_MASTER_SALT_LEN || saltLen > MAX_MASTER_SALT_LEN)
+                    throw PassStoreFileException.InvalidCryptoHeader;
+
+                byte[] salt = new byte[saltLen];
+                if (rd.Read(salt) < saltLen)
+                    throw PassStoreFileException.UnexpectedEndOfFile;
+
+                byte typeDiscrim = rd.ReadByte();
+                OuterEncryptionHeader outerEncrHdr;
+                if (typeDiscrim == ENCRYPT_ALGO_AES)
+                {
+                    byte[] iv = new byte[16];
+                    if (rd.Read(iv) < 16)
+                        throw PassStoreFileException.UnexpectedEndOfFile;
+                    outerEncrHdr = new OuterAesHeader(iv);
+                } else
+                {
+                    throw PassStoreFileException.InvalidCryptoHeader;
+                }
+
+                typeDiscrim = rd.ReadByte();
+                KdfHeader kdfHdr;
+                if (typeDiscrim == KDF_TYPE_AESKDF)
+                {
+                    int rounds = rd.Read7BitEncodedInt();
+                    byte[] seed = new byte[32];
+                    if (rd.Read(seed) < 32)
+                        throw PassStoreFileException.UnexpectedEndOfFile;
+                    kdfHdr = new AesKdfHeader(rounds, seed);
+                } else
+                {
+                    throw PassStoreFileException.InvalidCryptoHeader;
+                }
+
+                return new FileHeader(
+                    major, minor, salt,
+                    outerEncrHdr, kdfHdr
+                );
+            }
+            catch (EndOfStreamException)
+            {
+                throw PassStoreFileException.UnexpectedEndOfFile;
+            }
+        }
     };
 
     record OuterEncryptionHeader {}

src/KeyKeeper/RepositoryWindow.axaml.cs

@@ -1,13 +1,25 @@
+using System;
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Markup.Xaml;
+using KeyKeeper.PasswordStore;
+using KeyKeeper.PasswordStore.Crypto;
 
 namespace KeyKeeper;
 
 public partial class RepositoryWindow: Window
 {
+    public IPassStore? PassStore { private get; init; }
+
     public RepositoryWindow()
     {
         InitializeComponent();
     }
+
+    protected override void OnOpened(EventArgs e)
+    {
+        base.OnOpened(e);
+        if (PassStore!.Locked)
+            PassStore.Unlock(new CompositeKey("blablabla", null));
+    }
 }

src/KeyKeeper/Views/MainWindow.axaml.cs

@@ -3,6 +3,7 @@ using Avalonia.Controls;
 using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Platform.Storage;
+using KeyKeeper.PasswordStore;
 using KeyKeeper.ViewModels;
 using System;
 using System.Collections.Generic;
@@ -39,7 +40,11 @@ namespace KeyKeeper.Views
                 if (file.TryGetLocalPath() is string path)
                 {
                     (DataContext as MainWindowViewModel)!.CreateVault(path);
-                    OpenRepositoryWindow();
+                    OpenRepositoryWindow(new PassStoreFileAccessor(path, true, new StoreCreationOptions()
+                    {
+                        Key = new PasswordStore.Crypto.CompositeKey("blablabla", null),
+                        LockTimeoutSeconds = 800,
+                    }));
                 }
             }
         }
@@ -70,16 +75,17 @@ namespace KeyKeeper.Views
                 if (file.TryGetLocalPath() is string path)
                 {
                     (DataContext as MainWindowViewModel)!.OpenVault(path);
-                    OpenRepositoryWindow();
+                    OpenRepositoryWindow(new PassStoreFileAccessor(path, false, null));
                 }
             }
         }
 
-        private void OpenRepositoryWindow()
+        private void OpenRepositoryWindow(IPassStore store)
         {
             var repositoryWindow = new RepositoryWindow()
             {
                 DataContext = this.DataContext,
+                PassStore = store,
                 WindowStartupLocation = WindowStartupLocation.CenterScreen
             };
             repositoryWindow.Closed += (s, e) => this.Show();