fix: enforce root containment for renderFile/parseFile lookups (#870)

Made-with: Cursor

src/fs/loader.spec.ts

@@ -30,5 +30,11 @@ describe('fs/loader', function () {
       const result = toValueSync(loader.lookup('./foo/bar', LookupType.Partials, true, '/root/current'))
       expect(result).toBe(resolve('/root/foo/bar'))
     })
+    it('should enforce containment for LookupType.Root', function () {
+      const mockFs = { ...fs, existsSync: () => true, exists: async () => true }
+      const loader = new Loader({ relativeReference: false, fs: mockFs, extname: '', root: ['/safe'] } as any)
+      expect(() => toValueSync(loader.lookup('/etc/hosts', LookupType.Root, true)))
+        .toThrow(/ENOENT/)
+    })
   })
 })

src/fs/loader.ts

@@ -43,15 +43,12 @@ export class Loader {
 
   public * lookup (file: string, type: LookupType, sync?: boolean, currentFile?: string): Generator<unknown, string, string> {
     const dirs = this.options[type]
-    const enforceRoot = type !== LookupType.Root
     for (const filepath of this.candidates(file, dirs, currentFile)) {
-      if (enforceRoot) {
-        let allowed = false
-        for (const dir of dirs) {
-          if (yield this.contains(!!sync, dir, filepath)) { allowed = true; break }
-        }
-        if (!allowed) continue
+      let allowed = false
+      for (const dir of dirs) {
+        if (yield this.contains(!!sync, dir, filepath)) { allowed = true; break }
       }
+      if (!allowed) continue
       if (yield this.exists(!!sync, filepath)) return filepath
     }
     throw this.lookupError(file, dirs)

test/e2e/render-file.spec.ts

@@ -38,6 +38,7 @@ describe('#renderFile()', function () {
     return expect(html).toContain('"name": "liquidjs"')
   })
   it('should render file with context', async function () {
+    engine = new Liquid({ root: views, extname: '.html' })
     const html = await engine.renderFile(resolve(views, 'name.html'), { name: 'harttle' })
     return expect(html).toBe('My name is harttle.')
   })

test/e2e/render-to-node-stream.spec.ts

@@ -4,8 +4,8 @@ import { drainStream } from '../stub/stream'
 describe('.renderToNodeStream()', function () {
   it('should render to stream in Node.js', done => {
     const cjs = require('../../dist/liquid.node')
-    const engine = new cjs.Liquid()
-    const tpl = engine.parseFileSync(resolve(__dirname, '../stub/root/foo.html'))
+    const engine = new cjs.Liquid({ root: resolve(__dirname, '../stub/root/') })
+    const tpl = engine.parseFileSync('foo.html')
     const stream = engine.renderToNodeStream(tpl)
     let html = ''
     stream.on('data', (data: string) => { html += data })

test/integration/liquid/liquid.spec.ts

@@ -109,6 +109,7 @@ describe('Liquid', function () {
     })
   })
   describe('#renderFile', function () {
+    afterEach(restore)
     it('should throw with lookup list when file not exist', function () {
       const engine = new Liquid({
         root: ['/boo', '/root/'],
@@ -116,6 +117,22 @@ describe('Liquid', function () {
       })
       return expect(engine.renderFile('/not/exist.html')).rejects.toThrow(/Failed to lookup "\/not\/exist.html" in "\/boo,\/root\/"/)
     })
+    it('should reject absolute paths outside root', async function () {
+      mock({
+        '/safe/foo.html': 'safe',
+        '/etc/secret': 'SECRET'
+      })
+      const engine = new Liquid({ root: ['/safe'] })
+      await expect(engine.renderFile('/etc/secret')).rejects.toThrow(/Failed to lookup/)
+    })
+    it('should reject absolute paths outside root (sync)', function () {
+      mock({
+        '/safe/foo.html': 'safe',
+        '/etc/secret': 'SECRET'
+      })
+      const engine = new Liquid({ root: ['/safe'] })
+      expect(() => engine.renderFileSync('/etc/secret')).toThrow(/Failed to lookup/)
+    })
   })
   describe('#parseFile', function () {
     it('should throw with lookup list when file not exist', function () {
@@ -127,7 +144,7 @@ describe('Liquid', function () {
     })
     it('should fallback to require.resolve in Node.js', async function () {
       const engine = new Liquid({
-        root: ['/root/'],
+        root: [process.cwd()],
         extname: '.html'
       })
       const tpls = await engine.parseFileSync('jest')