feat: remote host SSH cases (CRUD, case-link, session launch, injection hardening)

src/mux-interface.ts

@@ -17,6 +17,7 @@ import type {
   CodexConfig,
   EffortLevel,
   GeminiConfig,
+  SessionRemote,
 } from './types.js';
 
 /**
@@ -33,6 +34,8 @@ export interface MuxSession {
   createdAt: number;
   /** Working directory */
   workingDir: string;
+  /** Remote execution metadata for local tmux sessions wrapping SSH */
+  remote?: SessionRemote;
   /** Session mode */
   mode: SessionMode;
   /** Whether webserver is attached to this session */
@@ -74,6 +77,8 @@ export interface CreateSessionOptions {
   effort?: EffortLevel;
   /** tmux history-limit (scrollback lines) to set for this session. */
   historyLimit?: number;
+  /** Remote execution metadata for local tmux sessions wrapping SSH */
+  remote?: SessionRemote;
 }
 
 /** Options for respawning a dead pane. */
@@ -96,6 +101,8 @@ export interface RespawnPaneOptions {
   effort?: EffortLevel;
   /** tmux history-limit (scrollback lines) to set for this session after respawn. */
   historyLimit?: number;
+  /** Remote execution metadata for local tmux sessions wrapping SSH */
+  remote?: SessionRemote;
 }
 
 /**

src/remote-hosts.ts

@@ -0,0 +1,223 @@
+import { existsSync, mkdirSync } from 'node:fs';
+import fs from 'node:fs/promises';
+import { join } from 'node:path';
+import { homedir } from 'node:os';
+import { exec } from 'node:child_process';
+import { promisify } from 'node:util';
+import type {
+  RemoteCase,
+  RemoteCommandMode,
+  RemoteHost,
+  RemoteSshOptions,
+  SessionMode,
+  SessionRemote,
+} from './types.js';
+
+const execAsync = promisify(exec);
+
+const REMOTE_HOSTS_FILE = 'remote-hosts.json';
+const REMOTE_CASES_FILE = 'remote-cases.json';
+
+export function remoteHostsPath(configDir: string): string {
+  return join(configDir, REMOTE_HOSTS_FILE);
+}
+
+export function remoteCasesPath(configDir: string): string {
+  return join(configDir, REMOTE_CASES_FILE);
+}
+
+async function readJsonArray<T>(path: string): Promise<T[]> {
+  try {
+    const raw = await fs.readFile(path, 'utf-8');
+    const parsed = JSON.parse(raw);
+    return Array.isArray(parsed) ? (parsed as T[]) : [];
+  } catch {
+    return [];
+  }
+}
+
+async function writeJsonArray<T>(configDir: string, path: string, value: T[]): Promise<void> {
+  if (!existsSync(configDir)) mkdirSync(configDir, { recursive: true });
+  await fs.writeFile(path, JSON.stringify(value, null, 2));
+}
+
+export async function readRemoteHosts(configDir: string): Promise<RemoteHost[]> {
+  return readJsonArray<RemoteHost>(remoteHostsPath(configDir));
+}
+
+export async function writeRemoteHosts(configDir: string, hosts: RemoteHost[]): Promise<void> {
+  await writeJsonArray(configDir, remoteHostsPath(configDir), hosts);
+}
+
+export async function readRemoteCases(configDir: string): Promise<RemoteCase[]> {
+  return readJsonArray<RemoteCase>(remoteCasesPath(configDir));
+}
+
+export async function writeRemoteCases(configDir: string, cases: RemoteCase[]): Promise<void> {
+  await writeJsonArray(configDir, remoteCasesPath(configDir), cases);
+}
+
+export function defaultRemoteCommandForMode(mode: SessionMode): string {
+  const commands: Record<RemoteCommandMode, string> = {
+    shell: 'exec bash -l',
+    claude: 'exec claude',
+    opencode: 'exec opencode',
+    codex: 'exec codex',
+    gemini: 'exec gemini',
+  };
+  return commands[mode as RemoteCommandMode] || commands.shell;
+}
+
+export function remoteSshTarget(host: Pick<RemoteHost, 'username' | 'host'>): string {
+  return `${host.username}@${host.host}`;
+}
+
+/**
+ * POSIX single-quote shell-escaping (end-quote, escaped-quote, restart-quote).
+ * Mirrors the helper in tmux-manager.ts so a value with spaces/metachars stays a
+ * single shell token. Used here for identity paths and `-o KEY=VALUE` options.
+ */
+function shellescape(str: string): string {
+  return "'" + str.replace(/'/g, "'\\''") + "'";
+}
+
+/**
+ * Expand a leading `~` or `$HOME` in an identity path to an absolute path.
+ *
+ * ssh does NOT expand `~` inside `-i` (the shell would, but we shellescape the
+ * value into a single quoted token so the shell never sees it). So we expand at
+ * build time, before escaping. Non-`~`/`$HOME` paths are returned unchanged.
+ */
+function expandIdentityPath(identityFile: string): string {
+  if (identityFile === '~') return homedir();
+  if (identityFile.startsWith('~/')) return join(homedir(), identityFile.slice(2));
+  if (identityFile === '$HOME') return homedir();
+  if (identityFile.startsWith('$HOME/')) return join(homedir(), identityFile.slice('$HOME/'.length));
+  return identityFile;
+}
+
+/**
+ * COD-107 — build the ordered, shell-safe ssh CONNECTION tokens shared by both
+ * the durable-launch command (`buildRemoteLaunchCommand`) and the tmux
+ * prerequisite probe (`buildRemoteTmuxCheckCommand`), so the prereq check and
+ * the real launch connect with IDENTICAL options (they can't drift).
+ *
+ * Returns the leading tokens of an ssh command line (NOT including `-t`, the
+ * target, or any remote command). Order:
+ *   ssh -o BatchMode=yes
+ *       [-p <port>]
+ *       [-i <abs-identity>]              (~/$HOME expanded, then shellescaped)
+ *       [-J <jumpHost>]                  (shellescaped, single token)
+ *       [-o ProxyCommand=nc -X 5 -x <socks> %h %p]   (ONE shellescaped -o token)
+ *       [-o <KEY=VALUE>] …               (each extra option, shellescaped)
+ *
+ * Escaping notes (the risky part):
+ *  - The ProxyCommand is emitted as a single shellescaped `-o KEY=VALUE`, so the
+ *    whole value (spaces + `%h`/`%p`) reaches ssh as one argument and `%h %p`
+ *    survive verbatim — ssh expands them to the real host/port, not the shell.
+ *  - Empty options ⇒ `['ssh', '-o BatchMode=yes']` (+ `-p` only when set), i.e.
+ *    byte-identical to the historical behavior.
+ */
+export function buildSshConnectionArgs(remote: RemoteSshOptions & Pick<RemoteHost, 'port'>): string[] {
+  const parts: string[] = ['ssh', '-o BatchMode=yes'];
+  if (remote.port) parts.push(`-p ${remote.port}`);
+  if (remote.identityFile) parts.push(`-i ${shellescape(expandIdentityPath(remote.identityFile))}`);
+  if (remote.jumpHost) parts.push(`-J ${shellescape(remote.jumpHost)}`);
+  if (remote.socksProxy) {
+    parts.push(`-o ${shellescape(`ProxyCommand=nc -X 5 -x ${remote.socksProxy} %h %p`)}`);
+  }
+  for (const opt of remote.extraSshOptions ?? []) {
+    parts.push(`-o ${shellescape(opt)}`);
+  }
+  return parts;
+}
+
+/**
+ * COD-104 — build the SSH command that checks the remote host has tmux.
+ *
+ * Durable remote sessions run the agent inside a tmux server ON the remote host
+ * (`tmux -L codeman new-session -A …`), so tmux is now a hard prerequisite there.
+ * `command -v tmux` exits 0 (and prints the path) when tmux is installed.
+ *
+ * COD-107 — connects with the SAME options as the real launch
+ * (`buildSshConnectionArgs`) so a proxied/custom-port/identity host that the
+ * launch can reach also passes the prereq probe (and vice-versa).
+ */
+export function buildRemoteTmuxCheckCommand(
+  host: Pick<RemoteHost, 'username' | 'host' | 'port'> & RemoteSshOptions
+): string {
+  const [ssh, ...connectionArgs] = buildSshConnectionArgs(host);
+  const parts = [ssh, connectionArgs[0], '-o ConnectTimeout=10', ...connectionArgs.slice(1)];
+  parts.push(remoteSshTarget(host), "'command -v tmux'");
+  return parts.join(' ');
+}
+
+export interface RemoteTmuxCheckResult {
+  ok: boolean;
+  /** Resolved tmux path on the remote (when ok). */
+  tmuxPath?: string;
+  /** Human-readable failure reason (when !ok). */
+  error?: string;
+}
+
+/**
+ * COD-104 — verify the remote host has tmux installed (required for durable
+ * remote sessions). Returns a structured result with a clear, user-facing error
+ * when tmux is missing or the host is unreachable. Never throws.
+ */
+export async function checkRemoteTmuxAvailable(
+  host: Pick<RemoteHost, 'username' | 'host' | 'port'> & RemoteSshOptions
+): Promise<RemoteTmuxCheckResult> {
+  const command = buildRemoteTmuxCheckCommand(host);
+  try {
+    const { stdout } = await execAsync(command, { timeout: 15_000 });
+    const tmuxPath = stdout.trim();
+    if (!tmuxPath) {
+      return {
+        ok: false,
+        error: `remote host ${host.host} needs tmux installed for durable remote sessions`,
+      };
+    }
+    return { ok: true, tmuxPath };
+  } catch (err) {
+    const stderr =
+      err && typeof err === 'object' && 'stderr' in err ? String((err as { stderr?: unknown }).stderr ?? '') : '';
+    // `command -v tmux` exits non-zero when tmux is absent (no stderr); a real
+    // connection failure surfaces ssh diagnostics on stderr.
+    if (stderr.trim()) {
+      return {
+        ok: false,
+        error: `could not verify tmux on remote host ${host.host}: ${stderr.trim()}`,
+      };
+    }
+    return {
+      ok: false,
+      error: `remote host ${host.host} needs tmux installed for durable remote sessions`,
+    };
+  }
+}
+
+export function remoteDisplayPath(
+  remote: Pick<SessionRemote, 'username' | 'host' | 'remotePath'> | { username: string; host: string; path: string }
+): string {
+  const path = 'remotePath' in remote ? remote.remotePath : remote.path;
+  return `${remote.username}@${remote.host}:${path}`;
+}
+
+export function toSessionRemote(host: RemoteHost, remoteCase: RemoteCase): SessionRemote {
+  return {
+    hostId: host.id,
+    label: host.label,
+    host: host.host,
+    username: host.username,
+    port: host.port,
+    remotePath: remoteCase.remotePath,
+    commands: host.commands,
+    // COD-107 — carry the advanced SSH options from host config into the session
+    // so the launch/prereq commands connect the same way the operator configured.
+    identityFile: host.identityFile,
+    socksProxy: host.socksProxy,
+    jumpHost: host.jumpHost,
+    extraSshOptions: host.extraSshOptions,
+  };
+}

src/session.ts

@@ -49,6 +49,7 @@ import {
   type CodexConfig,
   type EffortLevel,
   type GeminiConfig,
+  type SessionRemote,
 } from './types.js';
 import type { TerminalMultiplexer, MuxSession } from './mux-interface.js';
 import { TaskTracker, type BackgroundTask } from './task-tracker.js';
@@ -209,6 +210,10 @@ export function queryTmuxWindowSize(muxName: string, socket: string): { cols: nu
   return { cols: DEFAULT_PTY_COLS, rows: DEFAULT_PTY_ROWS };
 }
 
+export function resolveMuxAttachCwd(workingDir: string, remote?: SessionRemote): string {
+  return remote ? '/tmp' : workingDir;
+}
+
 /**
  * Represents a JSON message from Claude CLI's stream-json output format.
  * Messages are newline-delimited JSON objects parsed from PTY output.
@@ -385,6 +390,9 @@ export class Session extends EventEmitter {
   // tmux history-limit (scrollback lines) applied to this session's pane.
   private readonly _tmuxHistoryLimit: number;
 
+  // Remote execution metadata, present when this session runs over SSH through local tmux.
+  private readonly _remote?: SessionRemote;
+
   // Session color for visual differentiation
   private _color: import('./types.js').SessionColor = 'default';
 
@@ -456,6 +464,8 @@ export class Session extends EventEmitter {
       tmuxHistoryLimit?: number;
       /** Restored per-session attachment history. May include server-private external paths. */
       attachmentHistory?: SessionAttachmentHistoryItem[];
+      /** Remote execution metadata for sessions launched through SSH inside local tmux. */
+      remote?: SessionRemote;
     }
   ) {
     super();
@@ -528,6 +538,7 @@ export class Session extends EventEmitter {
       this._effort = config.effort;
     }
     this._tmuxHistoryLimit = config.tmuxHistoryLimit ?? DEFAULT_TMUX_HISTORY_LIMIT;
+    this._remote = config.remote;
     if (config.attachmentHistory && config.attachmentHistory.length > 0) {
       this.restoreAttachmentHistory(config.attachmentHistory);
     }
@@ -987,6 +998,7 @@ export class Session extends EventEmitter {
       pid: this.pid,
       status: this._status,
       workingDir: this.workingDir,
+      remote: this._remote,
       currentTaskId: this._currentTaskId,
       createdAt: this.createdAt,
       lastActivityAt: this._lastActivityAt,
@@ -1171,7 +1183,7 @@ export class Session extends EventEmitter {
         name: 'xterm-256color',
         cols: ptyCols,
         rows: ptyRows,
-        cwd: this.workingDir,
+        cwd: resolveMuxAttachCwd(this.workingDir, this._remote),
         env: buildMuxAttachEnv(),
       });
     } catch (spawnErr) {
@@ -1282,6 +1294,7 @@ export class Session extends EventEmitter {
             envOverrides: this._envOverrides,
             effort: this._effort,
             historyLimit: this._tmuxHistoryLimit,
+            remote: this._remote,
           },
           createSessionOptions: {
             sessionId: this.id,
@@ -1299,6 +1312,7 @@ export class Session extends EventEmitter {
             envOverrides: this._envOverrides,
             effort: this._effort,
             historyLimit: this._tmuxHistoryLimit,
+            remote: this._remote,
           },
           spawnErrLabel: 'mux attachment',
         });
@@ -1637,6 +1651,7 @@ export class Session extends EventEmitter {
             niceConfig: this._niceConfig,
             envOverrides: this._envOverrides,
             historyLimit: this._tmuxHistoryLimit,
+            remote: this._remote,
           },
           createSessionOptions: {
             sessionId: this.id,
@@ -1646,6 +1661,7 @@ export class Session extends EventEmitter {
             niceConfig: this._niceConfig,
             envOverrides: this._envOverrides,
             historyLimit: this._tmuxHistoryLimit,
+            remote: this._remote,
           },
           spawnErrLabel: 'shell mux attachment',
         });