agentHost: support SSH proxy configuration

Author: Girish Konda

src/vs/platform/agentHost/common/sshConfigParsing.ts

@@ -52,6 +52,10 @@ function parseSSHPathList(value: string): string[] {
 	return paths;
 }
 
+function parseSSHProxy(value: string | undefined): string | undefined {
+	return value && value.toLowerCase() !== 'none' ? value : undefined;
+}
+
 /**
  * Parse `ssh -G` output into a resolved config object.
  */
@@ -86,6 +90,10 @@ export function parseSSHGOutput(stdout: string): ISSHResolvedConfig {
 		identityFile: identityFiles,
 		identityAgent: map.get('identityagent') || undefined,
 		forwardAgent: map.get('forwardagent') === 'yes',
+		proxyJump: parseSSHProxy(map.get('proxyjump')),
+		proxyCommand: parseSSHProxy(map.get('proxycommand')),
+		proxyUseFdpass: map.get('proxyusefdpass') === 'yes',
+		hostKeyAlias: map.get('hostkeyalias') || undefined,
 		userKnownHostsFiles: parseSSHPathList(map.get('userknownhostsfile') ?? ''),
 		globalKnownHostsFiles: parseSSHPathList(map.get('globalknownhostsfile') ?? ''),
 		strictHostKeyChecking: strictHostKeyChecking && isSSHStrictHostKeyChecking(strictHostKeyChecking)

src/vs/platform/agentHost/common/sshRemoteAgentHost.ts

@@ -57,6 +57,14 @@ export interface ISSHAgentHostConfig {
 	readonly name: string;
 	/** SSH config host alias (e.g. "robfast2") for reconnection on restart. */
 	readonly sshConfigHost?: string;
+	/** Resolved ProxyJump value for this connect attempt. Never persisted. */
+	readonly proxyJump?: string;
+	/** Resolved ProxyCommand value for this connect attempt. Never persisted or logged. */
+	readonly proxyCommand?: string;
+	/** Whether the resolved SSH config requests ProxyUseFdpass. */
+	readonly proxyUseFdpass?: boolean;
+	/** Resolved HostKeyAlias used by OpenSSH's `%k` proxy token. */
+	readonly hostKeyAlias?: string;
 	/** Dev override: custom command to start the remote agent host instead of the default CLI. */
 	readonly remoteAgentHostCommand?: string;
 	/** When true, enables OpenSSH agent forwarding (auth-agent@openssh.com) for this connection. Requires {@link authMethod} to be Agent. */
@@ -114,11 +122,10 @@ export function computeSSHConnectionKey(config: { sshConfigHost?: string; userna
 }
 
 /**
- * A sanitized view of the SSH config that omits secret material
- * (password, private key path). Exposed on active connections so
- * consumers can inspect connection metadata without accessing credentials.
+ * A sanitized view of the SSH config that omits credentials and the raw
+ * ProxyCommand. Exposed on active connections for non-sensitive metadata.
  */
-export type ISSHAgentHostConfigSanitized = Omit<ISSHAgentHostConfig, 'password' | 'privateKeyPath'>;
+export type ISSHAgentHostConfigSanitized = Omit<ISSHAgentHostConfig, 'password' | 'privateKeyPath' | 'proxyCommand'>;
 
 export interface ISSHAgentHostConnection extends IDisposable {
 	/** The SSH config used to establish this connection (secrets stripped). */
@@ -276,6 +283,14 @@ export interface ISSHResolvedConfig {
 	readonly identityFile: string[];
 	readonly identityAgent: string | undefined;
 	readonly forwardAgent: boolean;
+	/** Effective ProxyJump value. */
+	readonly proxyJump?: string;
+	/** Effective ProxyCommand value. Sensitive; never persist or log it. */
+	readonly proxyCommand?: string;
+	/** Effective ProxyUseFdpass value. */
+	readonly proxyUseFdpass: boolean;
+	/** Effective HostKeyAlias value, including the explicit literal `none`. */
+	readonly hostKeyAlias?: string;
 	/**
 	 * `UserKnownHostsFile` paths, in priority order. `ssh -G` emits these as a
 	 * single space-separated list, so this is already split. Typically
@@ -322,6 +337,21 @@ export interface ISSHKeyboardInteractiveRequest {
 	readonly prompts: readonly ISSHKeyboardInteractivePrompt[];
 }
 
+export type SSHNativeAskpassPromptKind = 'confirm' | 'password' | 'passphrase' | 'secret';
+
+/**
+ * Prompt raised by a native OpenSSH ProxyCommand/ProxyJump helper through
+ * `SSH_ASKPASS`. The raw prompt is transient and must never be persisted or
+ * logged because implementations may include sensitive command context.
+ */
+export interface ISSHNativeAskpassRequest {
+	readonly requestId: string;
+	readonly connectionKey: string;
+	readonly displayHost: string;
+	readonly prompt: string;
+	readonly kind: SSHNativeAskpassPromptKind;
+}
+
 /**
  * One live remote agent host endpoint the user could connect to, as
  * surfaced by `code agent endpoints` on the remote machine. Deliberately
@@ -504,6 +534,18 @@ export interface ISSHRemoteAgentHostMainService {
 	 */
 	respondKeyboardInteractive(requestId: string, responses: readonly string[] | undefined): Promise<void>;
 
+	/** Fires when a native OpenSSH proxy helper needs confirmation or a secret. */
+	readonly onDidRequestNativeAskpass: Event<ISSHNativeAskpassRequest>;
+
+	/** Dismisses renderer UI when the owning native proxy helper no longer needs a prompt. */
+	readonly onDidCancelNativeAskpass: Event<string /* requestId */>;
+
+	/**
+	 * Answer a native OpenSSH proxy-helper prompt. Pass `undefined` to cancel
+	 * the owning connection attempt.
+	 */
+	respondNativeAskpass(requestId: string, response: string | undefined): Promise<void>;
+
 	/**
 	 * Fires when connect() discovers at least one live `editor`-owned
 	 * endpoint on the remote and needs the renderer to choose which

src/vs/platform/agentHost/electron-browser/sshRemoteAgentHostServiceImpl.ts

@@ -49,6 +49,7 @@ import {
 	type ISSHHostKeyVerificationRequest,
 	type ISSHHostKeysAnnouncement,
 	type ISSHKeyboardInteractiveRequest,
+	type ISSHNativeAskpassRequest,
 	type ISSHRemoteAgentHostMainService,
 	type ISSHResolvedConfig,
 	type ISSHConnectProgress,
@@ -502,6 +503,10 @@ export class SSHRemoteAgentHostService extends Disposable implements ISSHRemoteA
 			this._handleKeyboardInteractiveRequest(request);
 		}));
 
+		this._register(this._mainService.onDidRequestNativeAskpass(request => {
+			this._handleNativeAskpassRequest(request);
+		}));
+
 		// Bridge endpoint-selection requests (multiple live remote agent
 		// hosts found on the remote) to the stored per-host location
 		// preference, prompting with the shared preference modal only when
@@ -651,6 +656,55 @@ export class SSHRemoteAgentHostService extends Disposable implements ISSHRemoteA
 		}
 	}
 
+	private async _handleNativeAskpassRequest(request: ISSHNativeAskpassRequest): Promise<void> {
+		this._logService.info(`[SSHRemoteAgentHost] Native OpenSSH helper requested ${request.kind} input for ${request.displayHost}`);
+		const cts = new CancellationTokenSource();
+		const cancelListener = this._mainService.onDidCancelNativeAskpass(requestId => {
+			if (requestId === request.requestId) {
+				cts.cancel();
+			}
+		});
+
+		try {
+			let response: string | undefined;
+			if (request.kind === 'confirm') {
+				const { confirmed } = await this._dialogService.confirm({
+					type: 'warning',
+					message: localize('sshNativeAskpassConfirmMessage', "OpenSSH requires confirmation to connect through '{0}'.", request.displayHost),
+					detail: request.prompt,
+					primaryButton: localize('sshNativeAskpassConfirm', "&&Continue"),
+					cancelButton: localize('sshNativeAskpassDecline', "Cancel"),
+					custom: { icon: Codicon.shield },
+					token: cts.token,
+				});
+				if (cts.token.isCancellationRequested) {
+					return;
+				}
+				response = confirmed ? 'yes' : 'no';
+			} else {
+				const cleanedPrompt = request.prompt.replace(/[\s:]+$/, '');
+				response = await this._quickInputService.input({
+					title: request.displayHost,
+					prompt: cleanedPrompt || localize('sshNativeAskpassDefaultPrompt', "Authentication required for {0}", request.displayHost),
+					password: true,
+					ignoreFocusLost: true,
+				}, cts.token);
+				if (cts.token.isCancellationRequested) {
+					return;
+				}
+			}
+			await this._mainService.respondNativeAskpass(request.requestId, response);
+		} catch (err) {
+			this._logService.error('[SSHRemoteAgentHost] Failed handling native OpenSSH helper prompt', err);
+			try {
+				await this._mainService.respondNativeAskpass(request.requestId, undefined);
+			} catch { /* swallow */ }
+		} finally {
+			cancelListener.dispose();
+			cts.dispose();
+		}
+	}
+
 	/**
 	 * Decide whether to trust a server's host key, and tell the shared process.
 	 *