fix(security): constrain image fallback hook to workspace (#1232)

lib/hooks/image-analyzer-transformer.cjs

@@ -379,6 +379,47 @@ function outputSuccess(filePath, description, model, fileSize) {
 /**
  * Determine if hook should skip, with debug logging
  */
+function normalizePathForComparison(value) {
+  return process.platform === 'win32' ? value.toLowerCase() : value;
+}
+
+function isPathWithinWorkspace(workspaceRoot, candidatePath) {
+  const relativePath = path.relative(workspaceRoot, candidatePath);
+  return (
+    relativePath === '' ||
+    (!relativePath.startsWith('..') &&
+      !relativePath.startsWith(`..${path.sep}`) &&
+      !path.isAbsolute(relativePath))
+  );
+}
+
+function resolveWorkspaceFilePath(filePath) {
+  const workspaceRoot = (() => {
+    try {
+      return fs.realpathSync(process.cwd());
+    } catch {
+      return path.resolve(process.cwd());
+    }
+  })();
+  const absolutePath = path.resolve(process.cwd(), filePath);
+  const realFilePath = fs.realpathSync(absolutePath);
+
+  if (
+    !isPathWithinWorkspace(
+      normalizePathForComparison(workspaceRoot),
+      normalizePathForComparison(realFilePath)
+    )
+  ) {
+    debugLog('Skipping: file is outside the current workspace', {
+      workspaceRoot,
+      filePath: realFilePath,
+    });
+    return null;
+  }
+
+  return realFilePath;
+}
+
 function shouldSkipHook() {
   if (process.env.CCS_IMAGE_ANALYSIS_SKIP_HOOK === '1') {
     debugLog('Skipping: CCS_IMAGE_ANALYSIS_SKIP_HOOK=1');
@@ -484,11 +525,16 @@ async function processHook() {
       process.exit(0);
     }
 
-    const debugContext = getDebugContext(filePath, null);
+    const workspaceFilePath = resolveWorkspaceFilePath(filePath);
+    if (!workspaceFilePath) {
+      process.exit(0);
+    }
+
+    const debugContext = getDebugContext(workspaceFilePath, null);
     debugLog('Image analysis runtime prepared', debugContext);
 
-    const result = await analyzeFile(filePath);
+    const result = await analyzeFile(workspaceFilePath);
-    outputSuccess(filePath, result.description, result.model, result.fileSize);
+    outputSuccess(workspaceFilePath, result.description, result.model, result.fileSize);
   } catch (err) {
     if (process.env.CCS_DEBUG) {
       console.error('[CCS Hook] Error:', err.message);

tests/e2e/image-analyzer-hook.e2e.test.ts

@@ -169,6 +169,7 @@ function invokeHook(
     input: JSON.stringify(input),
     encoding: 'utf8',
     env: buildHookEnv(env),
+    cwd: TEST_DIR,
     timeout: 10000, // 10 second timeout per test
   });
 
@@ -187,6 +188,7 @@ function invokeHookAsync(
     const child = spawn('node', [HOOK_PATH], {
       env: buildHookEnv(env),
       stdio: ['pipe', 'pipe', 'pipe'],
+      cwd: TEST_DIR,
     });
 
     let stdout = '';
@@ -531,6 +533,7 @@ describe('Image Analyzer Hook', () => {
         input: 'not valid json',
         encoding: 'utf8',
         timeout: 5000,
+        cwd: TEST_DIR,
         env: {
           ...process.env,
           CCS_CLIPROXY_API_KEY: CLIPROXY_API_KEY,

tests/integration/image-analyzer-hook.test.ts

@@ -47,7 +47,10 @@ function enqueueResponses(...responses: MockResponse[]): void {
   queuedResponses = responses;
 }
 
-function invokeHook(env: Record<string, string> = {}): Promise<HookResult> {
+function invokeHook(
+  env: Record<string, string> = {},
+  options: { filePath?: string; cwd?: string } = {}
+): Promise<HookResult> {
   return new Promise((resolve, reject) => {
     const child = spawn('node', [HOOK_PATH], {
       env: {
@@ -68,6 +71,7 @@ function invokeHook(env: Record<string, string> = {}): Promise<HookResult> {
         ...env,
       },
       stdio: ['pipe', 'pipe', 'pipe'],
+      cwd: options.cwd ?? TEST_DIR,
     });
 
     let stdout = '';
@@ -98,7 +102,7 @@ function invokeHook(env: Record<string, string> = {}): Promise<HookResult> {
     child.stdin.end(
       JSON.stringify({
         tool_name: 'Read',
-        tool_input: { file_path: TEST_PNG_PATH },
+        tool_input: { file_path: options.filePath ?? TEST_PNG_PATH },
       })
     );
   });
@@ -198,6 +202,54 @@ describe('image analyzer hook regression coverage', () => {
     expect((requests[0].body as { model: string }).model).toBe('gpt-5.1-codex-mini');
   });
 
+  it('does not analyze files outside the current workspace', async () => {
+    const outsideDir = fs.mkdtempSync(path.join(os.tmpdir(), 'ccs-image-hook-outside-'));
+    const outsidePath = path.join(outsideDir, 'sensitive-outside-workspace.png');
+    createTestPng(outsidePath);
+
+    try {
+      const result = await invokeHook({}, { filePath: outsidePath });
+
+      expect(result.code).toBe(0);
+      expect(requests).toHaveLength(0);
+    } finally {
+      fs.rmSync(outsideDir, { recursive: true, force: true });
+    }
+  });
+
+  it.if(process.platform === 'win32')(
+    'analyzes Windows-style relative paths inside the current workspace',
+    async () => {
+      const nestedDir = path.join(TEST_DIR, 'windows-style-fixture-dir');
+      const nestedPath = path.join(nestedDir, 'inside-workspace.png');
+      fs.mkdirSync(nestedDir, { recursive: true });
+      createTestPng(nestedPath);
+
+      const result = await invokeHook({}, { filePath: path.win32.relative(TEST_DIR, nestedPath) });
+
+      expect(result.code).toBe(2);
+      expect(requests).toHaveLength(1);
+    }
+  );
+
+  it('does not analyze workspace symlinks that resolve outside the current workspace', async () => {
+    const outsideDir = fs.mkdtempSync(path.join(os.tmpdir(), 'ccs-image-hook-symlink-'));
+    const outsidePath = path.join(outsideDir, 'sensitive-symlink-target.png');
+    const linkPath = path.join(TEST_DIR, 'linked-sensitive.png');
+    createTestPng(outsidePath);
+
+    try {
+      fs.symlinkSync(outsidePath, linkPath);
+      const result = await invokeHook({}, { filePath: linkPath });
+
+      expect(result.code).toBe(0);
+      expect(requests).toHaveLength(0);
+    } finally {
+      fs.rmSync(linkPath, { force: true });
+      fs.rmSync(outsideDir, { recursive: true, force: true });
+    }
+  });
+
   it('skips analysis before contacting CLIProxy when the current provider has no mapped vision model', async () => {
     const result = await invokeHook({
       CCS_CURRENT_PROVIDER: 'unknown-provider',