feat: bind each node to the binary it runs at its first handshake; refuse changes that are not in a CI-signed manifest [CI]

backend/fleet/src/Fleet.Link/FleetLink.cs

@@ -72,6 +72,9 @@ public sealed class FleetLinkOptions
     /// 服务器必须在挑战里证明自己，之后这条链路用应用层加密；否则按旧的方式（没有固定信任根的节点）。
     /// </summary>
     public IServerVerifier? ServerVerifier { get; init; }
+
+    /// <summary>握手时自述正在运行的二进制（哈希和 CI 签名的清单）；没有就不上报（旧行为）。</summary>
+    public Func<BinaryAttestation?>? Attestation { get; init; }
 }
 
 /// <summary>
@@ -223,6 +226,16 @@ public sealed class FleetLink
     }
 
     /// <summary>挑战 → 签名 → 认证结果。失败返回原因；服务端禁用该节点时不再重试。</summary>
+    private void Attest(AuthParams auth)
+    {
+        if (_options.Attestation?.Invoke() is { } attestation)
+        {
+            auth.Binary = attestation.Sha256;
+            auth.Release = attestation.Manifest;
+            auth.ReleaseSignature = attestation.Signature;
+        }
+    }
+
     private async Task<string?> AuthenticateAsync(SecureTransport transport, CancellationToken ct)
     {
         using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(15), _time);
@@ -257,6 +270,7 @@ public sealed class FleetLink
                     Signature = Convert.ToBase64String(_options.Identity.Sign(SignaturePurpose.AuthSecure, _options.NodeId.Value, nonce.Nonce, serverEphemeralText, nodeEphemeralText)),
                     NodeEphemeral = nodeEphemeralText,
                 };
+                Attest(authParams);
                 RpcMessage secureRequest = RpcMessage.Request(1, FleetMethods.Auth, authParams, FleetRpcContext.Default.AuthParams);
                 await transport.SendAsync(new RpcFrame(FrameKind.Text, JsonSerializer.SerializeToUtf8Bytes(secureRequest, FleetRpcContext.Default.RpcMessage)), linked.Token);
                 transport.Enable(LinkCipher.ForNode(ephemeral, serverEphemeral, nonce.Nonce));
@@ -264,6 +278,7 @@ public sealed class FleetLink
             else
             {
                 authParams = new AuthParams { NodeId = _options.NodeId.Value, Signature = Convert.ToBase64String(_options.Identity.Sign(SignaturePurpose.Auth, _options.NodeId.Value, nonce.Nonce)) };
+                Attest(authParams);
                 RpcMessage request = RpcMessage.Request(1, FleetMethods.Auth, authParams, FleetRpcContext.Default.AuthParams);
                 await transport.SendAsync(new RpcFrame(FrameKind.Text, JsonSerializer.SerializeToUtf8Bytes(request, FleetRpcContext.Default.RpcMessage)), linked.Token);
             }