Use Stream.ReadExactly for deterministic readings

Author: Aeliux

src/Kryptor/Generators/UnixRandom.cs

@@ -27,9 +27,13 @@ public void Generate(byte[] buffer)
         {
             ProgressChanged?.Invoke(this, -1);
 
-            using (FileStream file = File.OpenRead("/dev/random"))
+            using (FileStream file = File.OpenRead("/dev/urandom"))
             {
+#if NET8_0_OR_GREATER
+                file.ReadExactly(buffer);
+#else
                 file.Read(buffer, 0, buffer.Length);
+#endif
             }
 
             ProgressChanged?.Invoke(this, 100);

src/Kryptor/Header.cs

@@ -128,7 +128,11 @@ public static T ReadHeader<T>(Stream stream)
             }
 
             byte[] buffer = new byte[headerSize];
+#if NET8_0_OR_GREATER
+            stream.ReadExactly(buffer, 0, headerSize);
+#else
             stream.Read(buffer, 0, headerSize);
+#endif
 
             T header;
             try
@@ -152,6 +156,7 @@ public static T ReadHeader<T>(Stream stream)
         /// <returns>
         /// A new instance of the <see cref="Header"/> class.
         /// </returns>
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Reliability", "CA2022:Avoid inexact read with 'Stream.Read'", Justification = "This behavior is intended")]
         public static T ReadHeaderClassic<T>(Stream stream)
             where T : Header, new()
         {
@@ -209,7 +214,11 @@ public static T ReadHeaderClassic<T>(Stream stream)
             stream.Seek(startPos, SeekOrigin.Begin);
 
             byte[] dataBuffer = new byte[endPos - startPos];
+#if NET8_0_OR_GREATER
+            stream.ReadExactly(dataBuffer);
+#else
             stream.Read(dataBuffer, 0, dataBuffer.Length);
+#endif
 
             T header = ReadHeaderInternal<T>(dataBuffer.Base64DecodeToString());
 

src/Kryptor/Helpers/AsyncCompat.cs

@@ -130,11 +130,19 @@ public static async Task ReadAsync(Stream stream, byte[] buffer, int offset, int
         {
             if (IsAsyncCompatible)
             {
+#if NET8_0_OR_GREATER
+                await stream.ReadExactlyAsync(buffer, offset, count, cancellationToken);
+#else
                 await stream.ReadAsync(buffer, offset, count, cancellationToken);
+#endif
             }
             else
             {
+#if NET8_0_OR_GREATER
+                stream.ReadExactly(buffer, offset, count);
+#else
                 stream.Read(buffer, offset, count);
+#endif
             }
         }