feat(filestore): wire AeadEncryptor into MsgBlock for at-rest encryption

Add FileStoreEncryptionTests covering ChaCha20-Poly1305 and AES-GCM round-trips and wrong-key rejection for the FSV2 AEAD path. Fix RestorePayload to wrap CryptographicException from AEAD decryption as InvalidDataException so RecoverBlocks correctly propagates key-mismatch failures instead of silently swallowing them.
2026-02-25 00:43:57 -05:00
parent 6c268c4143
commit f143295392
2 changed files with 115 additions and 1 deletions
--- a/tests/NATS.Server.Tests/FileStoreEncryptionTests.cs
+++ b/tests/NATS.Server.Tests/FileStoreEncryptionTests.cs
@@ -0,0 +1,104 @@
+// Go: TestFileStoreEncryption server/filestore_test.go
+// Reference: golang/nats-server/server/filestore.go:816-907 (genEncryptionKeys, recoverAEK, setupAEK)
+// Tests that block files are encrypted at rest and can be recovered with the same key.
+
+using System.Security.Cryptography;
+using NATS.Server.JetStream.Storage;
+
+namespace NATS.Server.Tests;
+
+public class FileStoreEncryptionTests
+{
+    [Fact]
+    public async Task Encrypted_block_round_trips_message()
+    {
+        // Go: TestFileStoreEncryption server/filestore_test.go
+        var dir = Directory.CreateTempSubdirectory();
+        var key = new byte[32];
+        RandomNumberGenerator.Fill(key);
+
+        await using (var store = new FileStore(new FileStoreOptions
+        {
+            Directory = dir.FullName,
+            Cipher = StoreCipher.ChaCha,
+            EncryptionKey = key,
+        }))
+        {
+            await store.AppendAsync("test.subj", "hello encrypted"u8.ToArray(), default);
+        }
+
+        // Raw block file should NOT contain plaintext
+        var blkFiles = Directory.GetFiles(dir.FullName, "*.blk");
+        blkFiles.ShouldNotBeEmpty();
+        var raw = File.ReadAllBytes(blkFiles[0]);
+        System.Text.Encoding.UTF8.GetString(raw).ShouldNotContain("hello encrypted");
+
+        // Recover with same key should return plaintext
+        await using var recovered = new FileStore(new FileStoreOptions
+        {
+            Directory = dir.FullName,
+            Cipher = StoreCipher.ChaCha,
+            EncryptionKey = key,
+        });
+        var msg = await recovered.LoadAsync(1, default);
+        msg.ShouldNotBeNull();
+        System.Text.Encoding.UTF8.GetString(msg.Payload.Span).ShouldBe("hello encrypted");
+    }
+
+    [Fact]
+    public async Task Encrypted_block_with_aes_round_trips()
+    {
+        var dir = Directory.CreateTempSubdirectory();
+        var key = new byte[32];
+        RandomNumberGenerator.Fill(key);
+
+        await using (var store = new FileStore(new FileStoreOptions
+        {
+            Directory = dir.FullName,
+            Cipher = StoreCipher.Aes,
+            EncryptionKey = key,
+        }))
+        {
+            await store.AppendAsync("aes.subj", "aes payload"u8.ToArray(), default);
+        }
+
+        await using var recovered = new FileStore(new FileStoreOptions
+        {
+            Directory = dir.FullName,
+            Cipher = StoreCipher.Aes,
+            EncryptionKey = key,
+        });
+        var msg = await recovered.LoadAsync(1, default);
+        msg.ShouldNotBeNull();
+        System.Text.Encoding.UTF8.GetString(msg.Payload.Span).ShouldBe("aes payload");
+    }
+
+    [Fact]
+    public async Task Wrong_key_fails_to_decrypt()
+    {
+        var dir = Directory.CreateTempSubdirectory();
+        var key1 = new byte[32];
+        var key2 = new byte[32];
+        RandomNumberGenerator.Fill(key1);
+        RandomNumberGenerator.Fill(key2);
+
+        await using (var store = new FileStore(new FileStoreOptions
+        {
+            Directory = dir.FullName,
+            Cipher = StoreCipher.ChaCha,
+            EncryptionKey = key1,
+        }))
+        {
+            await store.AppendAsync("secret", "data"u8.ToArray(), default);
+        }
+
+        // Recovery with wrong key should throw or return no messages
+        var act = () => new FileStore(new FileStoreOptions
+        {
+            Directory = dir.FullName,
+            Cipher = StoreCipher.ChaCha,
+            EncryptionKey = key2,
+        });
+        Should.Throw<Exception>(act);
+    }
+}