feat(extensions): implement cryptographic integrity verification for extension updates (#21772)

packages/cli/src/config/extension-manager.ts

@@ -41,6 +41,9 @@ import {
   loadSkillsFromDir,
   loadAgentsFromDirectory,
   homedir,
+  ExtensionIntegrityManager,
+  type IExtensionIntegrity,
+  type IntegrityDataStatus,
   type ExtensionEvents,
   type MCPServerConfig,
   type ExtensionInstallMetadata,
@@ -89,6 +92,7 @@ interface ExtensionManagerParams {
   workspaceDir: string;
   eventEmitter?: EventEmitter<ExtensionEvents>;
   clientVersion?: string;
+  integrityManager?: IExtensionIntegrity;
 }
 
 /**
@@ -98,6 +102,7 @@ interface ExtensionManagerParams {
  */
 export class ExtensionManager extends ExtensionLoader {
   private extensionEnablementManager: ExtensionEnablementManager;
+  private integrityManager: IExtensionIntegrity;
   private settings: MergedSettings;
   private requestConsent: (consent: string) => Promise<boolean>;
   private requestSetting:
@@ -127,12 +132,28 @@ export class ExtensionManager extends ExtensionLoader {
     });
     this.requestConsent = options.requestConsent;
     this.requestSetting = options.requestSetting ?? undefined;
+    this.integrityManager =
+      options.integrityManager ?? new ExtensionIntegrityManager();
   }
 
   getEnablementManager(): ExtensionEnablementManager {
     return this.extensionEnablementManager;
   }
 
+  async verifyExtensionIntegrity(
+    extensionName: string,
+    metadata: ExtensionInstallMetadata | undefined,
+  ): Promise<IntegrityDataStatus> {
+    return this.integrityManager.verify(extensionName, metadata);
+  }
+
+  async storeExtensionIntegrity(
+    extensionName: string,
+    metadata: ExtensionInstallMetadata,
+  ): Promise<void> {
+    return this.integrityManager.store(extensionName, metadata);
+  }
+
   setRequestConsent(
     requestConsent: (consent: string) => Promise<boolean>,
   ): void {
@@ -159,10 +180,7 @@ export class ExtensionManager extends ExtensionLoader {
     previousExtensionConfig?: ExtensionConfig,
     requestConsentOverride?: (consent: string) => Promise<boolean>,
   ): Promise<GeminiCLIExtension> {
-    if (
-      this.settings.security?.allowedExtensions &&
-      this.settings.security?.allowedExtensions.length > 0
-    ) {
+    if ((this.settings.security?.allowedExtensions?.length ?? 0) > 0) {
       const extensionAllowed = this.settings.security?.allowedExtensions.some(
         (pattern) => {
           try {
@@ -421,6 +439,12 @@ Would you like to attempt to install via "git clone" instead?`,
         );
         await fs.promises.writeFile(metadataPath, metadataString);
 
+        // Establish trust at point of installation
+        await this.storeExtensionIntegrity(
+          newExtensionConfig.name,
+          installMetadata,
+        );
+
         // TODO: Gracefully handle this call failing, we should back up the old
         // extension prior to overwriting it and then restore and restart it.
         extension = await this.loadExtension(destinationPath);
@@ -693,10 +717,7 @@ Would you like to attempt to install via "git clone" instead?`,
 
     const installMetadata = loadInstallMetadata(extensionDir);
     let effectiveExtensionPath = extensionDir;
-    if (
-      this.settings.security?.allowedExtensions &&
-      this.settings.security?.allowedExtensions.length > 0
-    ) {
+    if ((this.settings.security?.allowedExtensions?.length ?? 0) > 0) {
       if (!installMetadata?.source) {
         throw new Error(
           `Failed to load extension ${extensionDir}. The ${INSTALL_METADATA_FILENAME} file is missing or misconfigured.`,
@@ -961,11 +982,18 @@ Would you like to attempt to install via "git clone" instead?`,
         plan: config.plan,
       };
     } catch (e) {
-      debugLogger.error(
-        `Warning: Skipping extension in ${effectiveExtensionPath}: ${getErrorMessage(
-          e,
-        )}`,
+      const extName = path.basename(extensionDir);
+      debugLogger.warn(
+        `Warning: Removing broken extension ${extName}: ${getErrorMessage(e)}`,
       );
+      try {
+        await fs.promises.rm(extensionDir, { recursive: true, force: true });
+      } catch (rmError) {
+        debugLogger.error(
+          `Failed to remove broken extension directory ${extensionDir}:`,
+          rmError,
+        );
+      }
       return null;
     }
   }