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jesussamuel-bytejesussamuel-byte
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fix(config): prevent insecure system-wide configuration loading
## Summary Fixes insecure system-wide configuration loading on Windows and POSIX systems that could enable local privilege escalation and cross-user arbitrary command execution. ## Details - Implemented isPathSecureSync and isFileAndDirectorySecureSync in @google/gemini-cli-core to validate directory and file security before loading system-level configurations. - On Windows: Validates ACLs to ensure standard users/groups (e.g. Users, Authenticated Users, Everyone) do not have Write, Modify, or FullControl permissions. - On POSIX: Verifies root ownership (uid 0) and verifies that group and others do not have write permissions (S_IWGRP, S_IWOTH). Checks symlinks and resolved targets. - Updated _doLoadSettings in @google/gemini-cli to validate system configuration files (systemSettingsPath and systemDefaultsPath) before loading; securely skips insecure files and logs warnings. - Added comprehensive unit tests in packages/core/src/utils/security.test.ts and packages/cli/src/config/settings.test.ts. ## How to Validate 1. Run targeted security and settings unit tests: ```bash npx vitest run packages/core/src/utils/security.test.ts packages/cli/src/config/settings.test.ts ``` 2. Run full lint and typecheck: ```bash npm run lint:ci && npm run typecheck ```
1 parent 3c311be commit 7fe77b8

5 files changed

Lines changed: 1277 additions & 56 deletions

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‎packages/cli/src/config/settings.test.ts‎

Lines changed: 101 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -85,6 +85,7 @@ import {
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AuthType,
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type MCPServerConfig,
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} from '@google/gemini-cli-core';
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import * as core from '@google/gemini-cli-core';
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import { updateSettingsFilePreservingFormat } from '../utils/commentJson.js';
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import {
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getSettingsSchema,
@@ -3530,6 +3531,106 @@ MALICIOUS_VAR=allowed-because-trusted
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);
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});
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});
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describe('system configuration security', () => {
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beforeEach(() => {
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vi.mocked(isWorkspaceTrusted).mockReturnValue({
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isTrusted: true,
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source: 'file',
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});
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});
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it('should skip system-defaults.json when insecure and record a warning', () => {
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resetSettingsCacheForTesting();
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vi.mocked(fs.existsSync).mockImplementation(
3546+
(p) => String(p) === getSystemDefaultsPath(),
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);
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vi.mocked(fs.readFileSync).mockImplementation((p) => {
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if (String(p) === getSystemDefaultsPath()) {
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return JSON.stringify({
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hooks: {
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onSessionStart: { command: 'malicious-command.exe' },
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},
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});
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}
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return '';
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});
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vi.spyOn(core, 'isFileAndDirectorySecureSync').mockReturnValue({
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secure: false,
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reason:
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'Directory is insecure. User group Users has write permissions.',
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});
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const settings = loadSettings(MOCK_WORKSPACE_DIR);
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expect(settings.systemDefaults.settings).toEqual({});
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expect(settings.errors).toEqual(
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expect.arrayContaining([
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expect.objectContaining({
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message: expect.stringContaining('Skipping system defaults file'),
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severity: 'warning',
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}),
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]),
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);
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});
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it('should skip system settings.json when insecure and record a warning', () => {
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resetSettingsCacheForTesting();
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vi.mocked(fs.existsSync).mockImplementation(
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(p) => String(p) === getSystemSettingsPath(),
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);
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vi.mocked(fs.readFileSync).mockImplementation((p) => {
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if (String(p) === getSystemSettingsPath()) {
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return JSON.stringify({
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hooks: {
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onSessionStart: { command: 'malicious-command.exe' },
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},
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});
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}
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return '';
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});
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vi.spyOn(core, 'isFileAndDirectorySecureSync').mockReturnValue({
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secure: false,
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reason: 'File is not owned by root (uid 0).',
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});
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const settings = loadSettings(MOCK_WORKSPACE_DIR);
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expect(settings.system.settings).toEqual({});
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expect(settings.errors).toEqual(
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expect.arrayContaining([
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expect.objectContaining({
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message: expect.stringContaining('Skipping system settings file'),
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severity: 'warning',
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}),
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]),
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);
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});
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it('should load system-defaults.json when secure', () => {
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resetSettingsCacheForTesting();
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vi.mocked(fs.existsSync).mockImplementation(
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(p) => String(p) === getSystemDefaultsPath(),
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);
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vi.mocked(fs.readFileSync).mockImplementation((p) => {
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if (String(p) === getSystemDefaultsPath()) {
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return JSON.stringify({
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ui: { theme: 'corporate-theme' },
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});
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}
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return '';
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});
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vi.spyOn(core, 'isFileAndDirectorySecureSync').mockReturnValue({
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secure: true,
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});
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const settings = loadSettings(MOCK_WORKSPACE_DIR);
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expect(settings.systemDefaults.settings).toEqual({
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ui: { theme: 'corporate-theme' },
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});
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});
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});
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});
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});
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‎packages/cli/src/config/settings.ts‎

Lines changed: 31 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -21,6 +21,8 @@ import {
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AuthType,
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type AdminControlsSettings,
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createCache,
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isFileAndDirectorySecureSync,
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createPathSecurityCache,
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} from '@google/gemini-cli-core';
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import stripJsonComments from 'strip-json-comments';
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import { DefaultLight } from '../ui/themes/builtin/light/default-light.js';
@@ -844,8 +846,34 @@ function _doLoadSettings(workspaceDir: string): LoadedSettings {
844846
return { settings: {}, rawSettings: {} };
845847
};
846848

847-
const systemResult = load(systemSettingsPath);
848-
const systemDefaultsResult = load(systemDefaultsPath);
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const securityCache = createPathSecurityCache();
850+
851+
const loadSystemFile = (
852+
filePath: string,
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fileLabel: string,
854+
): { settings: Settings; rawSettings: Settings; rawJson?: string } => {
855+
if (!fs.existsSync(filePath)) {
856+
return { settings: {}, rawSettings: {} };
857+
}
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859+
const check = isFileAndDirectorySecureSync(filePath, securityCache);
860+
if (!check.secure) {
861+
settingsErrors.push({
862+
message: `Security Warning: Skipping ${fileLabel} file '${filePath}': ${check.reason}`,
863+
path: filePath,
864+
severity: 'warning',
865+
});
866+
return { settings: {}, rawSettings: {} };
867+
}
868+
869+
return load(filePath);
870+
};
871+
872+
const systemResult = loadSystemFile(systemSettingsPath, 'system settings');
873+
const systemDefaultsResult = loadSystemFile(
874+
systemDefaultsPath,
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'system defaults',
876+
);
849877
const userResult = load(USER_SETTINGS_PATH);
850878

851879
let workspaceResult: {
@@ -898,7 +926,7 @@ function _doLoadSettings(workspaceDir: string): LoadedSettings {
898926
);
899927
const isTrusted =
900928
isWorkspaceTrusted(initialTrustCheckSettings as Settings, workspaceDir)
901-
.isTrusted ?? false;
929+
?.isTrusted ?? false;
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903931
// Create a temporary merged settings object to pass to loadEnvironment.
904932
const tempMergedSettings = mergeSettings(

‎packages/core/src/index.ts‎

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@@ -97,6 +97,7 @@ export * from './utils/path-validator.js';
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export * from './utils/atCommandUtils.js';
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export * from './utils/retry.js';
9999
export * from './utils/shell-utils.js';
100+
export * from './utils/security.js';
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export {
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PolicyDecision,
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ApprovalMode,

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