fix(core): refactor linux sandbox to fix ARG_MAX crashes (#24286)

packages/core/src/sandbox/linux/LinuxSandboxManager.test.ts

@@ -6,10 +6,8 @@
 
 import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 import { LinuxSandboxManager } from './LinuxSandboxManager.js';
-import type { SandboxRequest } from '../../services/sandboxManager.js';
 import fs from 'node:fs';
 import path from 'node:path';
-import * as shellUtils from '../../utils/shell-utils.js';
 
 vi.mock('node:fs', async () => {
   const actual = await vi.importActual<typeof import('node:fs')>('node:fs');
@@ -74,111 +72,63 @@ describe('LinuxSandboxManager', () => {
     vi.restoreAllMocks();
   });
 
-  const getBwrapArgs = async (
-    req: SandboxRequest,
-    customManager?: LinuxSandboxManager,
-  ) => {
-    const mgr = customManager || manager;
-    const result = await mgr.prepareCommand(req);
-    expect(result.program).toBe('sh');
-    expect(result.args[0]).toBe('-c');
-    expect(result.args[1]).toBe(
-      'bpf_path="$1"; shift; exec bwrap "$@" 9< "$bpf_path"',
-    );
-    expect(result.args[2]).toBe('_');
-    expect(result.args[3]).toMatch(/gemini-cli-seccomp-.*\.bpf$/);
-    return result.args.slice(4);
-  };
-
   describe('prepareCommand', () => {
-    it('should correctly format the base command and args', async () => {
-      const bwrapArgs = await getBwrapArgs({
+    it('wraps the command and arguments correctly using a temporary file', async () => {
+      const result = await manager.prepareCommand({
         command: 'ls',
         args: ['-la'],
         cwd: workspace,
-        env: {},
+        env: { PATH: '/usr/bin' },
       });
 
-      expect(bwrapArgs).toEqual([
-        '--unshare-all',
-        '--new-session',
-        '--die-with-parent',
-        '--ro-bind',
-        '/',
-        '/',
-        '--dev',
-        '/dev',
-        '--proc',
-        '/proc',
-        '--tmpfs',
-        '/tmp',
-        '--ro-bind-try',
-        workspace,
-        workspace,
-        '--ro-bind',
-        `${workspace}/.gitignore`,
-        `${workspace}/.gitignore`,
-        '--ro-bind',
-        `${workspace}/.geminiignore`,
-        `${workspace}/.geminiignore`,
-        '--ro-bind',
-        `${workspace}/.git`,
-        `${workspace}/.git`,
-        '--seccomp',
-        '9',
-        '--',
-        'ls',
-        '-la',
-      ]);
-    });
-
-    it('binds workspace read-write when readonly is false', async () => {
-      const customManager = new LinuxSandboxManager({
-        workspace,
-        modeConfig: { readonly: false },
-      });
-      const bwrapArgs = await getBwrapArgs(
-        {
-          command: 'ls',
-          args: [],
-          cwd: workspace,
-          env: {},
-        },
-        customManager,
+      expect(result.program).toBe('sh');
+      expect(result.args[0]).toBe('-c');
+      expect(result.args[1]).toContain(
+        'exec bwrap --args 8 "$@" 8< "$args_path" 9< "$bpf_path"',
       );
-
-      expect(bwrapArgs).toContain('--bind-try');
-      expect(bwrapArgs).toContain(workspace);
+      expect(result.args[result.args.length - 3]).toBe('--');
+      expect(result.args[result.args.length - 2]).toBe('ls');
+      expect(result.args[result.args.length - 1]).toBe('-la');
+      expect(result.env['PATH']).toBe('/usr/bin');
     });
 
-    it('maps network permissions to --share-net', async () => {
-      const bwrapArgs = await getBwrapArgs({
-        command: 'curl',
+    it('cleans up the temporary arguments file', async () => {
+      const result = await manager.prepareCommand({
+        command: 'ls',
         args: [],
         cwd: workspace,
         env: {},
-        policy: { additionalPermissions: { network: true } },
       });
 
-      expect(bwrapArgs).toContain('--share-net');
+      expect(result.cleanup).toBeDefined();
+      result.cleanup!();
+
+      expect(fs.unlinkSync).toHaveBeenCalled();
+      const unlinkCall = vi.mocked(fs.unlinkSync).mock.calls[0];
+      expect(unlinkCall[0]).toMatch(/gemini-cli-bwrap-args-.*\.args$/);
     });
 
-    it('maps explicit write permissions to --bind-try', async () => {
-      const bwrapArgs = await getBwrapArgs({
-        command: 'touch',
-        args: [],
+    it('translates virtual commands', async () => {
+      const readResult = await manager.prepareCommand({
+        command: '__read',
+        args: [path.join(workspace, 'file.txt')],
         cwd: workspace,
         env: {},
-        policy: {
-          additionalPermissions: {
-            fileSystem: { write: ['/home/user/workspace/out/dir'] },
-          },
-        },
       });
+      // Length is 8: ['-c', '...', '_', bpf, args, '--', '/bin/cat', file]
+      expect(readResult.args[readResult.args.length - 2]).toBe('/bin/cat');
 
-      const index = bwrapArgs.indexOf('--bind-try');
-      expect(index).not.toBe(-1);
-      expect(bwrapArgs[index + 1]).toBe('/home/user/workspace/out/dir');
+      const writeResult = await manager.prepareCommand({
+        command: '__write',
+        args: [path.join(workspace, 'file.txt')],
+        cwd: workspace,
+        env: {},
+      });
+      // Length is 11: ['-c', '...', '_', bpf, args, '--', '/bin/sh', '-c', '...', '_', file]
+      expect(writeResult.args[writeResult.args.length - 5]).toBe('/bin/sh');
+      expect(writeResult.args[writeResult.args.length - 1]).toBe(
+        path.join(workspace, 'file.txt'),
+      );
     });
 
     it('rejects overrides in plan mode', async () => {
@@ -192,413 +142,9 @@ describe('LinuxSandboxManager', () => {
           args: [],
           cwd: workspace,
           env: {},
-          policy: { additionalPermissions: { network: true } },
+          policy: { networkAccess: true },
         }),
-      ).rejects.toThrow(
-        /Cannot override readonly\/network\/filesystem restrictions in Plan mode/,
-      );
+      ).rejects.toThrow(/Cannot override/);
     });
-
-    it('should correctly pass through the cwd to the resulting command', async () => {
-      const req: SandboxRequest = {
-        command: 'ls',
-        args: [],
-        cwd: '/different/cwd',
-        env: {},
-      };
-
-      const result = await manager.prepareCommand(req);
-
-      expect(result.cwd).toBe('/different/cwd');
-    });
-
-    it('should apply environment sanitization via the default mechanisms', async () => {
-      const req: SandboxRequest = {
-        command: 'test',
-        args: [],
-        cwd: workspace,
-        env: {
-          API_KEY: 'secret',
-          PATH: '/usr/bin',
-        },
-        policy: {
-          sanitizationConfig: {
-            allowedEnvironmentVariables: ['PATH'],
-            blockedEnvironmentVariables: ['API_KEY'],
-            enableEnvironmentVariableRedaction: true,
-          },
-        },
-      };
-
-      const result = await manager.prepareCommand(req);
-      expect(result.env['PATH']).toBe('/usr/bin');
-      expect(result.env['API_KEY']).toBeUndefined();
-    });
-
-    it('should allow network when networkAccess is true', async () => {
-      const bwrapArgs = await getBwrapArgs({
-        command: 'ls',
-        args: ['-la'],
-        cwd: workspace,
-        env: {},
-        policy: {
-          networkAccess: true,
-        },
-      });
-
-      expect(bwrapArgs).toContain('--share-net');
-    });
-
-    describe('governance files', () => {
-      it('should ensure governance files exist', async () => {
-        vi.mocked(fs.existsSync).mockReturnValue(false);
-
-        await getBwrapArgs({
-          command: 'ls',
-          args: [],
-          cwd: workspace,
-          env: {},
-        });
-
-        expect(fs.mkdirSync).toHaveBeenCalled();
-        expect(fs.openSync).toHaveBeenCalled();
-      });
-
-      it('should protect both the symlink and the real path if they differ', async () => {
-        vi.mocked(fs.realpathSync).mockImplementation((p) => {
-          if (p.toString() === `${workspace}/.gitignore`)
-            return '/shared/global.gitignore';
-          return p.toString();
-        });
-
-        const bwrapArgs = await getBwrapArgs({
-          command: 'ls',
-          args: [],
-          cwd: workspace,
-          env: {},
-        });
-
-        expect(bwrapArgs).toContain('--ro-bind');
-        expect(bwrapArgs).toContain(`${workspace}/.gitignore`);
-        expect(bwrapArgs).toContain('/shared/global.gitignore');
-
-        // Check that both are bound
-        const gitignoreIndex = bwrapArgs.indexOf(`${workspace}/.gitignore`);
-        expect(bwrapArgs[gitignoreIndex - 1]).toBe('--ro-bind');
-        expect(bwrapArgs[gitignoreIndex + 1]).toBe(`${workspace}/.gitignore`);
-
-        const realGitignoreIndex = bwrapArgs.indexOf(
-          '/shared/global.gitignore',
-        );
-        expect(bwrapArgs[realGitignoreIndex - 1]).toBe('--ro-bind');
-        expect(bwrapArgs[realGitignoreIndex + 1]).toBe(
-          '/shared/global.gitignore',
-        );
-      });
-    });
-
-    describe('allowedPaths', () => {
-      it('should parameterize allowed paths and normalize them', async () => {
-        const bwrapArgs = await getBwrapArgs({
-          command: 'node',
-          args: ['script.js'],
-          cwd: workspace,
-          env: {},
-          policy: {
-            allowedPaths: ['/tmp/cache', '/opt/tools', workspace],
-          },
-        });
-
-        expect(bwrapArgs).toContain('--bind-try');
-        expect(bwrapArgs[bwrapArgs.indexOf('/tmp/cache') - 1]).toBe(
-          '--bind-try',
-        );
-        expect(bwrapArgs[bwrapArgs.indexOf('/opt/tools') - 1]).toBe(
-          '--bind-try',
-        );
-      });
-
-      it('should grant read-write access to allowedPaths inside the workspace even when readonly mode is active', async () => {
-        const manager = new LinuxSandboxManager({
-          workspace,
-          modeConfig: { readonly: true },
-        });
-        const result = await manager.prepareCommand({
-          command: 'ls',
-          args: [],
-          cwd: workspace,
-          env: {},
-          policy: {
-            allowedPaths: [workspace + '/subdirectory'],
-          },
-        });
-        const bwrapArgs = result.args;
-        const bindIndex = bwrapArgs.indexOf(workspace + '/subdirectory');
-        expect(bwrapArgs[bindIndex - 1]).toBe('--bind-try');
-      });
-
-      it('should not bind the workspace twice even if it has a trailing slash in allowedPaths', async () => {
-        const bwrapArgs = await getBwrapArgs({
-          command: 'ls',
-          args: ['-la'],
-          cwd: workspace,
-          env: {},
-          policy: {
-            allowedPaths: [workspace + '/'],
-          },
-        });
-
-        const binds = bwrapArgs.filter((a) => a === workspace);
-        expect(binds.length).toBe(2);
-      });
-
-      it('should bind the parent directory of a non-existent path', async () => {
-        vi.mocked(fs.existsSync).mockImplementation((p) => {
-          if (p === '/home/user/workspace/new-file.txt') return false;
-          return true;
-        });
-
-        const bwrapArgs = await getBwrapArgs({
-          command: '__write',
-          args: ['/home/user/workspace/new-file.txt'],
-          cwd: workspace,
-          env: {},
-          policy: {
-            allowedPaths: ['/home/user/workspace/new-file.txt'],
-          },
-        });
-
-        const parentDir = '/home/user/workspace';
-        const bindIndex = bwrapArgs.lastIndexOf(parentDir);
-        expect(bindIndex).not.toBe(-1);
-        expect(bwrapArgs[bindIndex - 2]).toBe('--bind-try');
-      });
-    });
-
-    describe('virtual commands', () => {
-      it('should translate __read to cat', async () => {
-        const testFile = path.join(workspace, 'file.txt');
-        const bwrapArgs = await getBwrapArgs({
-          command: '__read',
-          args: [testFile],
-          cwd: workspace,
-          env: {},
-        });
-
-        // args are: [...bwrapBaseArgs, '--', '/bin/cat', '.../file.txt']
-        expect(bwrapArgs[bwrapArgs.length - 2]).toBe('/bin/cat');
-        expect(bwrapArgs[bwrapArgs.length - 1]).toBe(testFile);
-      });
-
-      it('should translate __write to sh -c cat', async () => {
-        const testFile = path.join(workspace, 'file.txt');
-        const bwrapArgs = await getBwrapArgs({
-          command: '__write',
-          args: [testFile],
-          cwd: workspace,
-          env: {},
-        });
-
-        // args are: [...bwrapBaseArgs, '--', '/bin/sh', '-c', 'tee -- "$@" > /dev/null', '_', '.../file.txt']
-        expect(bwrapArgs[bwrapArgs.length - 5]).toBe('/bin/sh');
-        expect(bwrapArgs[bwrapArgs.length - 4]).toBe('-c');
-        expect(bwrapArgs[bwrapArgs.length - 3]).toBe('tee -- "$@" > /dev/null');
-        expect(bwrapArgs[bwrapArgs.length - 2]).toBe('_');
-        expect(bwrapArgs[bwrapArgs.length - 1]).toBe(testFile);
-      });
-    });
-
-    describe('forbiddenPaths', () => {
-      it('should parameterize forbidden paths and explicitly deny them', async () => {
-        vi.mocked(fs.statSync).mockImplementation((p) => {
-          if (p.toString().includes('cache')) {
-            return { isDirectory: () => true } as fs.Stats;
-          }
-          return { isDirectory: () => false } as fs.Stats;
-        });
-        vi.mocked(fs.realpathSync).mockImplementation((p) => p.toString());
-
-        const customManager = new LinuxSandboxManager({
-          workspace,
-          forbiddenPaths: async () => ['/tmp/cache', '/opt/secret.txt'],
-        });
-
-        const bwrapArgs = await getBwrapArgs(
-          {
-            command: 'ls',
-            args: ['-la'],
-            cwd: workspace,
-            env: {},
-          },
-          customManager,
-        );
-
-        const cacheIndex = bwrapArgs.indexOf('/tmp/cache');
-        expect(bwrapArgs[cacheIndex - 1]).toBe('--tmpfs');
-
-        const secretIndex = bwrapArgs.indexOf('/opt/secret.txt');
-        expect(bwrapArgs[secretIndex - 2]).toBe('--ro-bind');
-        expect(bwrapArgs[secretIndex - 1]).toBe('/dev/null');
-      });
-
-      it('resolves forbidden symlink paths to their real paths', async () => {
-        vi.mocked(fs.statSync).mockImplementation(
-          () => ({ isDirectory: () => false }) as fs.Stats,
-        );
-        vi.mocked(fs.realpathSync).mockImplementation((p) => {
-          if (p === '/tmp/forbidden-symlink') return '/opt/real-target.txt';
-          return p.toString();
-        });
-
-        const customManager = new LinuxSandboxManager({
-          workspace,
-          forbiddenPaths: async () => ['/tmp/forbidden-symlink'],
-        });
-
-        const bwrapArgs = await getBwrapArgs(
-          {
-            command: 'ls',
-            args: ['-la'],
-            cwd: workspace,
-            env: {},
-          },
-          customManager,
-        );
-
-        const secretIndex = bwrapArgs.indexOf('/opt/real-target.txt');
-        expect(bwrapArgs[secretIndex - 2]).toBe('--ro-bind');
-        expect(bwrapArgs[secretIndex - 1]).toBe('/dev/null');
-      });
-
-      it('explicitly denies non-existent forbidden paths to prevent creation', async () => {
-        const error = new Error('File not found') as NodeJS.ErrnoException;
-        error.code = 'ENOENT';
-        vi.mocked(fs.statSync).mockImplementation(() => {
-          throw error;
-        });
-        vi.mocked(fs.realpathSync).mockImplementation((p) => p.toString());
-
-        const customManager = new LinuxSandboxManager({
-          workspace,
-          forbiddenPaths: async () => ['/tmp/not-here.txt'],
-        });
-
-        const bwrapArgs = await getBwrapArgs(
-          {
-            command: 'ls',
-            args: [],
-            cwd: workspace,
-            env: {},
-          },
-          customManager,
-        );
-
-        const idx = bwrapArgs.indexOf('/tmp/not-here.txt');
-        expect(bwrapArgs[idx - 2]).toBe('--symlink');
-        expect(bwrapArgs[idx - 1]).toBe('/dev/null');
-      });
-
-      it('masks directory symlinks with tmpfs for both paths', async () => {
-        vi.mocked(fs.statSync).mockImplementation(
-          () => ({ isDirectory: () => true }) as fs.Stats,
-        );
-        vi.mocked(fs.realpathSync).mockImplementation((p) => {
-          if (p === '/tmp/dir-link') return '/opt/real-dir';
-          return p.toString();
-        });
-
-        const customManager = new LinuxSandboxManager({
-          workspace,
-          forbiddenPaths: async () => ['/tmp/dir-link'],
-        });
-
-        const bwrapArgs = await getBwrapArgs(
-          {
-            command: 'ls',
-            args: [],
-            cwd: workspace,
-            env: {},
-          },
-          customManager,
-        );
-
-        const idx = bwrapArgs.indexOf('/opt/real-dir');
-        expect(bwrapArgs[idx - 1]).toBe('--tmpfs');
-      });
-
-      it('should override allowed paths if a path is also in forbidden paths', async () => {
-        vi.mocked(fs.statSync).mockImplementation(
-          () => ({ isDirectory: () => true }) as fs.Stats,
-        );
-        vi.mocked(fs.realpathSync).mockImplementation((p) => p.toString());
-
-        const customManager = new LinuxSandboxManager({
-          workspace,
-          forbiddenPaths: async () => ['/tmp/conflict'],
-        });
-
-        const bwrapArgs = await getBwrapArgs(
-          {
-            command: 'ls',
-            args: ['-la'],
-            cwd: workspace,
-            env: {},
-            policy: {
-              allowedPaths: ['/tmp/conflict'],
-            },
-          },
-          customManager,
-        );
-
-        // Conflict should have been filtered out of allow list (--bind-try)
-        expect(bwrapArgs).not.toContain('--bind-try');
-        expect(bwrapArgs).not.toContain('--bind-try-ro');
-
-        // It should only appear as a forbidden path (via --tmpfs)
-        const conflictIdx = bwrapArgs.indexOf('/tmp/conflict');
-        expect(conflictIdx).toBeGreaterThan(0);
-        expect(bwrapArgs[conflictIdx - 1]).toBe('--tmpfs');
-      });
-    });
-  });
-
-  it('blocks .env and .env.* files in the workspace root', async () => {
-    vi.mocked(shellUtils.spawnAsync).mockImplementation((cmd, args) => {
-      if (cmd === 'find' && args?.[0] === workspace) {
-        // Assert that find is NOT excluding dotfiles
-        expect(args).not.toContain('-not');
-        expect(args).toContain('-prune');
-
-        return Promise.resolve({
-          status: 0,
-          stdout: Buffer.from(
-            `${workspace}/.env\0${workspace}/.env.local\0${workspace}/.env.test\0`,
-          ),
-        } as unknown as ReturnType<typeof shellUtils.spawnAsync>);
-      }
-      return Promise.resolve({
-        status: 0,
-        stdout: Buffer.from(''),
-      } as unknown as ReturnType<typeof shellUtils.spawnAsync>);
-    });
-
-    const bwrapArgs = await getBwrapArgs({
-      command: 'ls',
-      args: [],
-      cwd: workspace,
-      env: {},
-    });
-
-    const bindsIndex = bwrapArgs.indexOf('--seccomp');
-    const binds = bwrapArgs.slice(0, bindsIndex);
-
-    expect(binds).toContain(`${workspace}/.env`);
-    expect(binds).toContain(`${workspace}/.env.local`);
-    expect(binds).toContain(`${workspace}/.env.test`);
-
-    // Verify they are bound to a mask file
-    const envIndex = binds.indexOf(`${workspace}/.env`);
-    expect(binds[envIndex - 2]).toBe('--bind');
-    expect(binds[envIndex - 1]).toMatch(/gemini-cli-mask-file-.*mocked\/mask/);
   });
 });

packages/core/src/sandbox/linux/LinuxSandboxManager.ts

@@ -5,7 +5,7 @@
  */
 
 import fs from 'node:fs';
-import { join, dirname, normalize } from 'node:path';
+import { join, dirname } from 'node:path';
 import os from 'node:os';
 import {
   type SandboxManager,
@@ -14,8 +14,6 @@ import {
   type SandboxedCommand,
   type SandboxPermissions,
   GOVERNANCE_FILES,
-  getSecretFileFindArgs,
-  sanitizePaths,
   type ParsedSandboxDenial,
   resolveSandboxPaths,
 } from '../../services/sandboxManager.js';
@@ -24,24 +22,18 @@ import {
   sanitizeEnvironment,
   getSecureSanitizationConfig,
 } from '../../services/environmentSanitization.js';
-import { debugLogger } from '../../utils/debugLogger.js';
-import { spawnAsync } from '../../utils/shell-utils.js';
 import {
   isStrictlyApproved,
   verifySandboxOverrides,
   getCommandName,
 } from '../utils/commandUtils.js';
-import {
-  tryRealpath,
-  resolveGitWorktreePaths,
-  isErrnoException,
-} from '../utils/fsUtils.js';
 import {
   isKnownSafeCommand,
   isDangerousCommand,
 } from '../utils/commandSafety.js';
 import { parsePosixSandboxDenials } from '../utils/sandboxDenialUtils.js';
 import { handleReadWriteCommands } from '../utils/sandboxReadWriteUtils.js';
+import { buildBwrapArgs } from './bwrapArgsBuilder.js';
 
 let cachedBpfPath: string | undefined;
 
@@ -240,175 +232,40 @@ export class LinuxSandboxManager implements SandboxManager {
 
     const sanitizedEnv = sanitizeEnvironment(req.env, sanitizationConfig);
 
-    const bwrapArgs: string[] = [
-      '--unshare-all',
-      '--new-session', // Isolate session
-      '--die-with-parent', // Prevent orphaned runaway processes
-    ];
-
-    if (mergedAdditional.network) {
-      bwrapArgs.push('--share-net');
-    }
-
-    bwrapArgs.push(
-      '--ro-bind',
-      '/',
-      '/',
-      '--dev', // Creates a safe, minimal /dev (replaces --dev-bind)
-      '/dev',
-      '--proc', // Creates a fresh procfs for the unshared PID namespace
-      '/proc',
-      '--tmpfs', // Provides an isolated, writable /tmp directory
-      '/tmp',
-    );
-
-    const workspacePath = tryRealpath(this.options.workspace);
-
-    const bindFlag = workspaceWrite ? '--bind-try' : '--ro-bind-try';
-
-    if (workspaceWrite) {
-      bwrapArgs.push(
-        '--bind-try',
-        this.options.workspace,
-        this.options.workspace,
-      );
-      if (workspacePath !== this.options.workspace) {
-        bwrapArgs.push('--bind-try', workspacePath, workspacePath);
-      }
-    } else {
-      bwrapArgs.push(
-        '--ro-bind-try',
-        this.options.workspace,
-        this.options.workspace,
-      );
-      if (workspacePath !== this.options.workspace) {
-        bwrapArgs.push('--ro-bind-try', workspacePath, workspacePath);
-      }
-    }
-
-    const { worktreeGitDir, mainGitDir } =
-      resolveGitWorktreePaths(workspacePath);
-    if (worktreeGitDir) {
-      bwrapArgs.push(bindFlag, worktreeGitDir, worktreeGitDir);
-    }
-    if (mainGitDir) {
-      bwrapArgs.push(bindFlag, mainGitDir, mainGitDir);
-    }
-
-    const includeDirs = sanitizePaths(this.options.includeDirectories);
-    for (const includeDir of includeDirs) {
-      try {
-        const resolved = tryRealpath(includeDir);
-        bwrapArgs.push('--ro-bind-try', resolved, resolved);
-      } catch {
-        // Ignore
-      }
-    }
-
     const { allowed: allowedPaths, forbidden: forbiddenPaths } =
       await resolveSandboxPaths(this.options, req);
 
-    const normalizedWorkspace = normalize(workspacePath).replace(/\/$/, '');
-    for (const allowedPath of allowedPaths) {
-      const resolved = tryRealpath(allowedPath);
-      if (!fs.existsSync(resolved)) {
-        // If the path doesn't exist, we still want to allow access to its parent
-        // if it's explicitly allowed, to enable creating it.
-        try {
-          const resolvedParent = tryRealpath(dirname(resolved));
-          bwrapArgs.push(
-            req.command === '__write' ? '--bind-try' : bindFlag,
-            resolvedParent,
-            resolvedParent,
-          );
-        } catch {
-          // Ignore
-        }
-        continue;
-      }
-      const normalizedAllowedPath = normalize(resolved).replace(/\/$/, '');
-      if (normalizedAllowedPath !== normalizedWorkspace) {
-        bwrapArgs.push('--bind-try', resolved, resolved);
-      }
-    }
-
-    const additionalReads = sanitizePaths(mergedAdditional.fileSystem?.read);
-    for (const p of additionalReads) {
-      try {
-        const safeResolvedPath = tryRealpath(p);
-        bwrapArgs.push('--ro-bind-try', safeResolvedPath, safeResolvedPath);
-      } catch (e: unknown) {
-        debugLogger.warn(e instanceof Error ? e.message : String(e));
-      }
-    }
-
-    const additionalWrites = sanitizePaths(mergedAdditional.fileSystem?.write);
-    for (const p of additionalWrites) {
-      try {
-        const safeResolvedPath = tryRealpath(p);
-        bwrapArgs.push('--bind-try', safeResolvedPath, safeResolvedPath);
-      } catch (e: unknown) {
-        debugLogger.warn(e instanceof Error ? e.message : String(e));
-      }
-    }
-
     for (const file of GOVERNANCE_FILES) {
       const filePath = join(this.options.workspace, file.path);
       touch(filePath, file.isDirectory);
-      const realPath = tryRealpath(filePath);
-      bwrapArgs.push('--ro-bind', filePath, filePath);
-      if (realPath !== filePath) {
-        bwrapArgs.push('--ro-bind', realPath, realPath);
-      }
     }
 
-    for (const p of forbiddenPaths) {
-      let resolved: string;
-      try {
-        resolved = tryRealpath(p); // Forbidden paths should still resolve to block the real path
-        if (!fs.existsSync(resolved)) continue;
-      } catch (e: unknown) {
-        debugLogger.warn(
-          `Failed to resolve forbidden path ${p}: ${e instanceof Error ? e.message : String(e)}`,
-        );
-        bwrapArgs.push('--ro-bind', '/dev/null', p);
-        continue;
-      }
-      try {
-        const stat = fs.statSync(resolved);
-        if (stat.isDirectory()) {
-          bwrapArgs.push('--tmpfs', resolved, '--remount-ro', resolved);
-        } else {
-          bwrapArgs.push('--ro-bind', '/dev/null', resolved);
-        }
-      } catch (e: unknown) {
-        if (isErrnoException(e) && e.code === 'ENOENT') {
-          bwrapArgs.push('--symlink', '/dev/null', resolved);
-        } else {
-          debugLogger.warn(
-            `Failed to stat forbidden path ${resolved}: ${e instanceof Error ? e.message : String(e)}`,
-          );
-          bwrapArgs.push('--ro-bind', '/dev/null', resolved);
-        }
-      }
-    }
-
-    // Mask secret files (.env, .env.*)
-    bwrapArgs.push(
-      ...(await this.getSecretFilesArgs(req.policy?.allowedPaths)),
-    );
+    const bwrapArgs = await buildBwrapArgs({
+      workspace: this.options.workspace,
+      workspaceWrite,
+      networkAccess,
+      allowedPaths,
+      forbiddenPaths,
+      additionalPermissions: mergedAdditional,
+      includeDirectories: this.options.includeDirectories || [],
+      maskFilePath: this.getMaskFilePath(),
+      isWriteCommand: req.command === '__write',
+    });
 
     const bpfPath = getSeccompBpfPath();
-
     bwrapArgs.push('--seccomp', '9');
-    bwrapArgs.push('--', finalCommand, ...finalArgs);
+
+    const argsPath = this.writeArgsToTempFile(bwrapArgs);
 
     const shArgs = [
       '-c',
-      'bpf_path="$1"; shift; exec bwrap "$@" 9< "$bpf_path"',
+      'bpf_path="$1"; args_path="$2"; shift 2; exec bwrap --args 8 "$@" 8< "$args_path" 9< "$bpf_path"',
       '_',
       bpfPath,
-      ...bwrapArgs,
+      argsPath,
+      '--',
+      finalCommand,
+      ...finalArgs,
     ];
 
     return {
@@ -416,70 +273,23 @@ export class LinuxSandboxManager implements SandboxManager {
       args: shArgs,
       env: sanitizedEnv,
       cwd: req.cwd,
+      cleanup: () => {
+        try {
+          fs.unlinkSync(argsPath);
+        } catch {
+          // Ignore cleanup errors
+        }
+      },
     };
   }
 
-  /**
-   * Generates bubblewrap arguments to mask secret files.
-   */
-  private async getSecretFilesArgs(allowedPaths?: string[]): Promise<string[]> {
-    const args: string[] = [];
-    const maskPath = this.getMaskFilePath();
-    const paths = sanitizePaths(allowedPaths) || [];
-    const searchDirs = new Set([this.options.workspace, ...paths]);
-    const findPatterns = getSecretFileFindArgs();
-
-    for (const dir of searchDirs) {
-      try {
-        // Use the native 'find' command for performance and to catch nested secrets.
-        // We limit depth to 3 to keep it fast while covering common nested structures.
-        // We use -prune to skip heavy directories efficiently while matching dotfiles.
-        const findResult = await spawnAsync('find', [
-          dir,
-          '-maxdepth',
-          '3',
-          '-type',
-          'd',
-          '(',
-          '-name',
-          '.git',
-          '-o',
-          '-name',
-          'node_modules',
-          '-o',
-          '-name',
-          '.venv',
-          '-o',
-          '-name',
-          '__pycache__',
-          '-o',
-          '-name',
-          'dist',
-          '-o',
-          '-name',
-          'build',
-          ')',
-          '-prune',
-          '-o',
-          '-type',
-          'f',
-          ...findPatterns,
-          '-print0',
-        ]);
-
-        const files = findResult.stdout.toString().split('\0');
-        for (const file of files) {
-          if (file.trim()) {
-            args.push('--bind', maskPath, file.trim());
-          }
-        }
-      } catch (e) {
-        debugLogger.log(
-          `LinuxSandboxManager: Failed to find or mask secret files in ${dir}`,
-          e,
-        );
-      }
-    }
-    return args;
+  private writeArgsToTempFile(args: string[]): string {
+    const tempFile = join(
+      os.tmpdir(),
+      `gemini-cli-bwrap-args-${Date.now()}-${Math.random().toString(36).slice(2)}.args`,
+    );
+    const content = Buffer.from(args.join('\0') + '\0');
+    fs.writeFileSync(tempFile, content, { mode: 0o600 });
+    return tempFile;
   }
 }

packages/core/src/sandbox/linux/bwrapArgsBuilder.test.ts

@@ -0,0 +1,296 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { buildBwrapArgs, type BwrapArgsOptions } from './bwrapArgsBuilder.js';
+import fs from 'node:fs';
+import * as shellUtils from '../../utils/shell-utils.js';
+
+vi.mock('node:fs', async () => {
+  const actual = await vi.importActual<typeof import('node:fs')>('node:fs');
+  return {
+    ...actual,
+    default: {
+      // @ts-expect-error - Property 'default' does not exist on type 'typeof import("node:fs")'
+      ...actual.default,
+      existsSync: vi.fn(() => true),
+      realpathSync: vi.fn((p) => p.toString()),
+      statSync: vi.fn(() => ({ isDirectory: () => true }) as fs.Stats),
+      mkdirSync: vi.fn(),
+      mkdtempSync: vi.fn((prefix: string) => prefix + 'mocked'),
+      openSync: vi.fn(),
+      closeSync: vi.fn(),
+      writeFileSync: vi.fn(),
+      readdirSync: vi.fn(() => []),
+      chmodSync: vi.fn(),
+      unlinkSync: vi.fn(),
+      rmSync: vi.fn(),
+    },
+    existsSync: vi.fn(() => true),
+    realpathSync: vi.fn((p) => p.toString()),
+    statSync: vi.fn(() => ({ isDirectory: () => true }) as fs.Stats),
+    mkdirSync: vi.fn(),
+    mkdtempSync: vi.fn((prefix: string) => prefix + 'mocked'),
+    openSync: vi.fn(),
+    closeSync: vi.fn(),
+    writeFileSync: vi.fn(),
+    readdirSync: vi.fn(() => []),
+    chmodSync: vi.fn(),
+    unlinkSync: vi.fn(),
+    rmSync: vi.fn(),
+  };
+});
+
+vi.mock('../../utils/shell-utils.js', async (importOriginal) => {
+  const actual =
+    await importOriginal<typeof import('../../utils/shell-utils.js')>();
+  return {
+    ...actual,
+    spawnAsync: vi.fn(() =>
+      Promise.resolve({ status: 0, stdout: Buffer.from('') }),
+    ),
+    initializeShellParsers: vi.fn(),
+    isStrictlyApproved: vi.fn().mockResolvedValue(true),
+  };
+});
+
+describe('buildBwrapArgs', () => {
+  const workspace = '/home/user/workspace';
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    vi.mocked(fs.existsSync).mockReturnValue(true);
+    vi.mocked(fs.realpathSync).mockImplementation((p) => p.toString());
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  const defaultOptions: BwrapArgsOptions = {
+    workspace,
+    workspaceWrite: false,
+    networkAccess: false,
+    allowedPaths: [],
+    forbiddenPaths: [],
+    additionalPermissions: {},
+    includeDirectories: [],
+    maskFilePath: '/tmp/mask',
+    isWriteCommand: false,
+  };
+
+  it('should correctly format the base arguments', async () => {
+    const args = await buildBwrapArgs(defaultOptions);
+
+    expect(args).toEqual([
+      '--unshare-all',
+      '--new-session',
+      '--die-with-parent',
+      '--ro-bind',
+      '/',
+      '/',
+      '--dev',
+      '/dev',
+      '--proc',
+      '/proc',
+      '--tmpfs',
+      '/tmp',
+      '--ro-bind-try',
+      workspace,
+      workspace,
+      '--ro-bind',
+      `${workspace}/.gitignore`,
+      `${workspace}/.gitignore`,
+      '--ro-bind',
+      `${workspace}/.geminiignore`,
+      `${workspace}/.geminiignore`,
+      '--ro-bind',
+      `${workspace}/.git`,
+      `${workspace}/.git`,
+    ]);
+  });
+
+  it('binds workspace read-write when workspaceWrite is true', async () => {
+    const args = await buildBwrapArgs({
+      ...defaultOptions,
+      workspaceWrite: true,
+    });
+
+    expect(args).toContain('--bind-try');
+    const bindIndex = args.indexOf('--bind-try');
+    expect(args[bindIndex + 1]).toBe(workspace);
+  });
+
+  it('maps network permissions to --share-net', async () => {
+    const args = await buildBwrapArgs({
+      ...defaultOptions,
+      networkAccess: true,
+    });
+
+    expect(args).toContain('--share-net');
+  });
+
+  it('maps explicit write permissions to --bind-try', async () => {
+    const args = await buildBwrapArgs({
+      ...defaultOptions,
+      additionalPermissions: {
+        fileSystem: { write: ['/home/user/workspace/out/dir'] },
+      },
+    });
+
+    const index = args.indexOf('--bind-try');
+    expect(index).not.toBe(-1);
+    expect(args[index + 1]).toBe('/home/user/workspace/out/dir');
+  });
+
+  it('should protect both the symlink and the real path of governance files', async () => {
+    vi.mocked(fs.realpathSync).mockImplementation((p) => {
+      if (p.toString() === `${workspace}/.gitignore`)
+        return '/shared/global.gitignore';
+      return p.toString();
+    });
+
+    const args = await buildBwrapArgs(defaultOptions);
+
+    expect(args).toContain('--ro-bind');
+    expect(args).toContain(`${workspace}/.gitignore`);
+    expect(args).toContain('/shared/global.gitignore');
+  });
+
+  it('should parameterize allowed paths and normalize them', async () => {
+    const args = await buildBwrapArgs({
+      ...defaultOptions,
+      allowedPaths: ['/tmp/cache', '/opt/tools', workspace],
+    });
+
+    expect(args).toContain('--bind-try');
+    expect(args[args.indexOf('/tmp/cache') - 1]).toBe('--bind-try');
+    expect(args[args.indexOf('/opt/tools') - 1]).toBe('--bind-try');
+  });
+
+  it('should bind the parent directory of a non-existent path', async () => {
+    vi.mocked(fs.existsSync).mockImplementation((p) => {
+      if (p === '/home/user/workspace/new-file.txt') return false;
+      return true;
+    });
+
+    const args = await buildBwrapArgs({
+      ...defaultOptions,
+      allowedPaths: ['/home/user/workspace/new-file.txt'],
+      isWriteCommand: true,
+    });
+
+    const parentDir = '/home/user/workspace';
+    const bindIndex = args.lastIndexOf(parentDir);
+    expect(bindIndex).not.toBe(-1);
+    expect(args[bindIndex - 2]).toBe('--bind-try');
+  });
+
+  it('should parameterize forbidden paths and explicitly deny them', async () => {
+    vi.mocked(fs.statSync).mockImplementation((p) => {
+      if (p.toString().includes('cache')) {
+        return { isDirectory: () => true } as fs.Stats;
+      }
+      return { isDirectory: () => false } as fs.Stats;
+    });
+
+    const args = await buildBwrapArgs({
+      ...defaultOptions,
+      forbiddenPaths: ['/tmp/cache', '/opt/secret.txt'],
+    });
+
+    const cacheIndex = args.indexOf('/tmp/cache');
+    expect(args[cacheIndex - 1]).toBe('--tmpfs');
+
+    const secretIndex = args.indexOf('/opt/secret.txt');
+    expect(args[secretIndex - 2]).toBe('--ro-bind');
+    expect(args[secretIndex - 1]).toBe('/dev/null');
+  });
+
+  it('resolves forbidden symlink paths to their real paths', async () => {
+    vi.mocked(fs.statSync).mockImplementation(
+      () => ({ isDirectory: () => false }) as fs.Stats,
+    );
+    vi.mocked(fs.realpathSync).mockImplementation((p) => {
+      if (p === '/tmp/forbidden-symlink') return '/opt/real-target.txt';
+      return p.toString();
+    });
+
+    const args = await buildBwrapArgs({
+      ...defaultOptions,
+      forbiddenPaths: ['/tmp/forbidden-symlink'],
+    });
+
+    const secretIndex = args.indexOf('/opt/real-target.txt');
+    expect(args[secretIndex - 2]).toBe('--ro-bind');
+    expect(args[secretIndex - 1]).toBe('/dev/null');
+  });
+
+  it('masks directory symlinks with tmpfs for both paths', async () => {
+    vi.mocked(fs.statSync).mockImplementation(
+      () => ({ isDirectory: () => true }) as fs.Stats,
+    );
+    vi.mocked(fs.realpathSync).mockImplementation((p) => {
+      if (p === '/tmp/dir-link') return '/opt/real-dir';
+      return p.toString();
+    });
+
+    const args = await buildBwrapArgs({
+      ...defaultOptions,
+      forbiddenPaths: ['/tmp/dir-link'],
+    });
+
+    const idx = args.indexOf('/opt/real-dir');
+    expect(args[idx - 1]).toBe('--tmpfs');
+  });
+
+  it('should override allowed paths if a path is also in forbidden paths', async () => {
+    vi.mocked(fs.statSync).mockImplementation(
+      () => ({ isDirectory: () => true }) as fs.Stats,
+    );
+
+    const args = await buildBwrapArgs({
+      ...defaultOptions,
+      forbiddenPaths: ['/tmp/conflict'],
+      allowedPaths: ['/tmp/conflict'],
+    });
+
+    const bindIndex = args.findIndex(
+      (a, i) => a === '--bind-try' && args[i + 1] === '/tmp/conflict',
+    );
+    const tmpfsIndex = args.findIndex(
+      (a, i) => a === '--tmpfs' && args[i + 1] === '/tmp/conflict',
+    );
+
+    expect(bindIndex).toBeGreaterThan(-1);
+    expect(tmpfsIndex).toBeGreaterThan(bindIndex);
+    expect(args[tmpfsIndex + 1]).toBe('/tmp/conflict');
+  });
+
+  it('blocks .env and .env.* files', async () => {
+    vi.mocked(shellUtils.spawnAsync).mockImplementation((cmd, args) => {
+      if (cmd === 'find' && args?.[0] === workspace) {
+        return Promise.resolve({
+          status: 0,
+          stdout: Buffer.from(`${workspace}/.env\0${workspace}/.env.local\0`),
+        } as unknown as ReturnType<typeof shellUtils.spawnAsync>);
+      }
+      return Promise.resolve({
+        status: 0,
+        stdout: Buffer.from(''),
+      } as unknown as ReturnType<typeof shellUtils.spawnAsync>);
+    });
+
+    const args = await buildBwrapArgs(defaultOptions);
+
+    expect(args).toContain(`${workspace}/.env`);
+    expect(args).toContain(`${workspace}/.env.local`);
+
+    const envIndex = args.indexOf(`${workspace}/.env`);
+    expect(args[envIndex - 2]).toBe('--bind');
+    expect(args[envIndex - 1]).toBe('/tmp/mask');
+  });
+});

packages/core/src/sandbox/linux/bwrapArgsBuilder.ts

@@ -0,0 +1,263 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import fs from 'node:fs';
+import { join, dirname, normalize } from 'node:path';
+import {
+  type SandboxPermissions,
+  GOVERNANCE_FILES,
+  getSecretFileFindArgs,
+  sanitizePaths,
+} from '../../services/sandboxManager.js';
+import {
+  tryRealpath,
+  resolveGitWorktreePaths,
+  isErrnoException,
+} from '../utils/fsUtils.js';
+import { spawnAsync } from '../../utils/shell-utils.js';
+import { debugLogger } from '../../utils/debugLogger.js';
+
+/**
+ * Options for building bubblewrap (bwrap) arguments.
+ */
+export interface BwrapArgsOptions {
+  workspace: string;
+  workspaceWrite: boolean;
+  networkAccess: boolean;
+  allowedPaths: string[];
+  forbiddenPaths: string[];
+  additionalPermissions: SandboxPermissions;
+  includeDirectories: string[];
+  maskFilePath: string;
+  isWriteCommand: boolean;
+}
+
+/**
+ * Builds the list of bubblewrap arguments based on the provided options.
+ */
+export async function buildBwrapArgs(
+  options: BwrapArgsOptions,
+): Promise<string[]> {
+  const bwrapArgs: string[] = [
+    '--unshare-all',
+    '--new-session', // Isolate session
+    '--die-with-parent', // Prevent orphaned runaway processes
+  ];
+
+  if (options.networkAccess || options.additionalPermissions.network) {
+    bwrapArgs.push('--share-net');
+  }
+
+  bwrapArgs.push(
+    '--ro-bind',
+    '/',
+    '/',
+    '--dev', // Creates a safe, minimal /dev (replaces --dev-bind)
+    '/dev',
+    '--proc', // Creates a fresh procfs for the unshared PID namespace
+    '/proc',
+    '--tmpfs', // Provides an isolated, writable /tmp directory
+    '/tmp',
+  );
+
+  const workspacePath = tryRealpath(options.workspace);
+
+  const bindFlag = options.workspaceWrite ? '--bind-try' : '--ro-bind-try';
+
+  if (options.workspaceWrite) {
+    bwrapArgs.push('--bind-try', options.workspace, options.workspace);
+    if (workspacePath !== options.workspace) {
+      bwrapArgs.push('--bind-try', workspacePath, workspacePath);
+    }
+  } else {
+    bwrapArgs.push('--ro-bind-try', options.workspace, options.workspace);
+    if (workspacePath !== options.workspace) {
+      bwrapArgs.push('--ro-bind-try', workspacePath, workspacePath);
+    }
+  }
+
+  const { worktreeGitDir, mainGitDir } = resolveGitWorktreePaths(workspacePath);
+  if (worktreeGitDir) {
+    bwrapArgs.push(bindFlag, worktreeGitDir, worktreeGitDir);
+  }
+  if (mainGitDir) {
+    bwrapArgs.push(bindFlag, mainGitDir, mainGitDir);
+  }
+
+  const includeDirs = sanitizePaths(options.includeDirectories);
+  for (const includeDir of includeDirs) {
+    try {
+      const resolved = tryRealpath(includeDir);
+      bwrapArgs.push('--ro-bind-try', resolved, resolved);
+    } catch {
+      // Ignore
+    }
+  }
+
+  const normalizedWorkspace = normalize(workspacePath).replace(/\/$/, '');
+  for (const allowedPath of options.allowedPaths) {
+    const resolved = tryRealpath(allowedPath);
+    if (!fs.existsSync(resolved)) {
+      // If the path doesn't exist, we still want to allow access to its parent
+      // if it's explicitly allowed, to enable creating it.
+      try {
+        const resolvedParent = tryRealpath(dirname(resolved));
+        bwrapArgs.push(
+          options.isWriteCommand ? '--bind-try' : bindFlag,
+          resolvedParent,
+          resolvedParent,
+        );
+      } catch {
+        // Ignore
+      }
+      continue;
+    }
+    const normalizedAllowedPath = normalize(resolved).replace(/\/$/, '');
+    if (normalizedAllowedPath !== normalizedWorkspace) {
+      bwrapArgs.push('--bind-try', resolved, resolved);
+    }
+  }
+
+  const additionalReads = sanitizePaths(
+    options.additionalPermissions.fileSystem?.read,
+  );
+  for (const p of additionalReads) {
+    try {
+      const safeResolvedPath = tryRealpath(p);
+      bwrapArgs.push('--ro-bind-try', safeResolvedPath, safeResolvedPath);
+    } catch (e: unknown) {
+      debugLogger.warn(e instanceof Error ? e.message : String(e));
+    }
+  }
+
+  const additionalWrites = sanitizePaths(
+    options.additionalPermissions.fileSystem?.write,
+  );
+  for (const p of additionalWrites) {
+    try {
+      const safeResolvedPath = tryRealpath(p);
+      bwrapArgs.push('--bind-try', safeResolvedPath, safeResolvedPath);
+    } catch (e: unknown) {
+      debugLogger.warn(e instanceof Error ? e.message : String(e));
+    }
+  }
+
+  for (const file of GOVERNANCE_FILES) {
+    const filePath = join(options.workspace, file.path);
+    const realPath = tryRealpath(filePath);
+    bwrapArgs.push('--ro-bind', filePath, filePath);
+    if (realPath !== filePath) {
+      bwrapArgs.push('--ro-bind', realPath, realPath);
+    }
+  }
+
+  for (const p of options.forbiddenPaths) {
+    let resolved: string;
+    try {
+      resolved = tryRealpath(p); // Forbidden paths should still resolve to block the real path
+      if (!fs.existsSync(resolved)) continue;
+    } catch (e: unknown) {
+      debugLogger.warn(
+        `Failed to resolve forbidden path ${p}: ${e instanceof Error ? e.message : String(e)}`,
+      );
+      bwrapArgs.push('--ro-bind', '/dev/null', p);
+      continue;
+    }
+    try {
+      const stat = fs.statSync(resolved);
+      if (stat.isDirectory()) {
+        bwrapArgs.push('--tmpfs', resolved, '--remount-ro', resolved);
+      } else {
+        bwrapArgs.push('--ro-bind', '/dev/null', resolved);
+      }
+    } catch (e: unknown) {
+      if (isErrnoException(e) && e.code === 'ENOENT') {
+        bwrapArgs.push('--symlink', '/dev/null', resolved);
+      } else {
+        debugLogger.warn(
+          `Failed to stat forbidden path ${resolved}: ${e instanceof Error ? e.message : String(e)}`,
+        );
+        bwrapArgs.push('--ro-bind', '/dev/null', resolved);
+      }
+    }
+  }
+
+  // Mask secret files (.env, .env.*)
+  const secretArgs = await getSecretFilesArgs(
+    options.workspace,
+    options.allowedPaths,
+    options.maskFilePath,
+  );
+  bwrapArgs.push(...secretArgs);
+
+  return bwrapArgs;
+}
+
+/**
+ * Generates bubblewrap arguments to mask secret files.
+ */
+async function getSecretFilesArgs(
+  workspace: string,
+  allowedPaths: string[],
+  maskPath: string,
+): Promise<string[]> {
+  const args: string[] = [];
+  const searchDirs = new Set([workspace, ...allowedPaths]);
+  const findPatterns = getSecretFileFindArgs();
+
+  for (const dir of searchDirs) {
+    try {
+      // Use the native 'find' command for performance and to catch nested secrets.
+      // We limit depth to 3 to keep it fast while covering common nested structures.
+      // We use -prune to skip heavy directories efficiently while matching dotfiles.
+      const findResult = await spawnAsync('find', [
+        dir,
+        '-maxdepth',
+        '3',
+        '-type',
+        'd',
+        '(',
+        '-name',
+        '.git',
+        '-o',
+        '-name',
+        'node_modules',
+        '-o',
+        '-name',
+        '.venv',
+        '-o',
+        '-name',
+        '__pycache__',
+        '-o',
+        '-name',
+        'dist',
+        '-o',
+        '-name',
+        'build',
+        ')',
+        '-prune',
+        '-o',
+        '-type',
+        'f',
+        ...findPatterns,
+        '-print0',
+      ]);
+
+      const files = findResult.stdout.toString().split('\0');
+      for (const file of files) {
+        if (file.trim()) {
+          args.push('--bind', maskPath, file.trim());
+        }
+      }
+    } catch (e) {
+      debugLogger.log(
+        `LinuxSandboxManager: Failed to find or mask secret files in ${dir}`,
+        e,
+      );
+    }
+  }
+  return args;
+}