Files
voice-cat/clients/windows/VoiceCat.App/Forms/ServerIdentityDialog.cs
Talon 63b241cc2e feat(M4): Windows WinForms client, TOFU identity pinning, VAD threshold + always-on mode
Core ABI extensions (voicecat.h):
- vc_list_channels / vc_list_users / vc_list_user_streams — pull-based snapshot getters
  for the channel-tree and user-list UI; session_model_mu_ guards cross-thread reads
- VC_EVENT_JOIN_RESULT / vc_join_channel — channel join with optional password
- VC_EVENT_SERVER_IDENTITY + vc_confirm_server_identity — TOFU gate that blocks io_thread_
  until the UI approves or rejects; pins TLS leaf-cert SHA-256 (not declared Ed25519)
- vc_get_server_identity_display — Ed25519 fingerprint for human-readable display only
- VC_INPUT_ALWAYS_ON = 2 in vc_input_mode — transmit unconditionally, no VAD gate
- vc_set_vad_threshold — live RMS threshold update (0.0–1.0); EnergyVadProcessor stores
  it atomically so the audio RT path reads without a lock

C++ implementation:
- SessionModel::apply_snapshot / apply_channel_event fixed to populate parent_id,
  password_protected, and max_users (were permanently zeroed)
- TlsContext::peer_cert_fingerprint — SHA-256 of peer leaf cert DER via mbedTLS
- TofuStore split into peek (read-only) + pin (write) so first-connect only persists
  after user approval; tofu_store_path in vc_config for per-user pin file location
- TcpAcceptor uses dual-stack IPv6+IPv4 fallback (fixes localhost → ::1 on Windows)
- windows-client CMake preset: Release shared DLL, static MinGW runtime, no tools/tests
- New C++ tests: test_channel_user_list_abi, test_tofu_flow (14/14 green)

Windows client (clients/windows/ — .NET 10 WinForms):
- VoiceCat.Interop: LibraryImport P/Invoke surface, UnmanagedCallersOnly callbacks,
  Channel<VoiceCatEvent> event delivery drained by 30ms WinForms Timer
- VoiceCat.App: ConnectDialog (saved servers, DPAPI password storage), ServerIdentity-
  Dialog (TOFU first-connect / mismatch warning), MainForm (channel TreeView, user
  ListBox, RichTextBox chat, voice controls, device pickers, VAD/PTT/always-on mode,
  per-user gain/mute/NR tuning, VAD sensitivity TrackBar, level meter ProgressBar)
- PttKeyCaptureDialog — focus-scoped PTT key capture (documented limitation)
- PerUserTuningDialog — real-time gain/mute/NR applied to all of a user's streams
- Accessibility: explicit AccessibleName/Description on every control, & mnemonics,
  Activity log ListBox as durable screen-reader record, AutomationNotification for
  curated live announcements

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-06-17 00:35:16 +02:00

67 lines
3.0 KiB
C#

using VoiceCat.Interop;
namespace VoiceCat.App.Forms;
/// <summary>
/// TOFU server-identity confirmation (M4). Shown only for VcTofuStatus.FirstConnect/Mismatch
/// — never Matched (that's the silent-success "subsequent connects verify the pin" path
/// docs/security.md describes; showing a dialog on every routine reconnect would be exactly
/// the "overly chatty" experience this project avoids elsewhere too).
/// DialogResult.OK = accept (and the caller should call ConfirmServerIdentity(true) and, for
/// FirstConnect/Mismatch, the core persists the new pin); DialogResult.Cancel = reject.
/// </summary>
public partial class ServerIdentityDialog : Form
{
public ServerIdentityDialog(VcTofuStatus status, string certFingerprintHex, string identityDisplayHex)
{
InitializeComponent();
string formattedCertFp = FormatFingerprint(certFingerprintHex);
string formattedIdentityFp = string.IsNullOrEmpty(identityDisplayHex)
? "(not yet available)"
: FormatFingerprint(identityDisplayHex);
if (status == VcTofuStatus.Mismatch)
{
Text = "WARNING: Server identity changed";
lblWarning.Text =
"WARNING: This server's identity has CHANGED since you last connected.\r\n\r\n" +
"This could mean the server was reinstalled, OR that someone is intercepting " +
"your connection. If you did not expect this server's identity to change, " +
"choose Cancel.";
lblFingerprint.Text = $"New certificate fingerprint:\r\n{formattedCertFp}\r\n\r\n" +
$"Server also identifies as:\r\n{formattedIdentityFp}";
btnAccept.Text = "&Trust the new identity anyway";
}
else
{
Text = "New server — verify identity";
lblWarning.Text =
"You have not connected to this server before. If you have verified its " +
"fingerprint with the server operator through another channel, choose Trust " +
"and connect. Otherwise, choose Cancel.";
lblFingerprint.Text = $"Certificate fingerprint:\r\n{formattedCertFp}\r\n\r\n" +
$"Server also identifies as:\r\n{formattedIdentityFp}";
btnAccept.Text = "&Trust and connect";
}
}
protected override void OnShown(EventArgs e)
{
base.OnShown(e);
// Force a screen reader to read the warning text immediately on dialog activation,
// rather than landing focus straight on a button and silently skipping it.
lblWarning.Focus();
}
private static string FormatFingerprint(string hex)
{
// Groups of 4 hex chars, like a product key — easier to read/dictate/compare than one
// unbroken 64-character string.
var groups = new List<string>();
for (int i = 0; i < hex.Length; i += 4)
groups.Add(hex.Substring(i, Math.Min(4, hex.Length - i)));
return string.Join(' ', groups);
}
}