feat(serve-static): support absolute root (honojs#3420)

* feat(serve-static): support absolute root

* add bun runtime test

* don't use `Request`

* add code for deno

* remove unnecessay `console.log`

* use `normalizeFilePath` instead of `URL`

* use `URL` for `options.root`

* don't allow directory traversal and fix the behavior when root including `../`

runtime-tests/bun/index.test.tsx

@@ -1,4 +1,6 @@
 import { afterAll, afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import fs from 'fs/promises'
+import path from 'path'
 import { stream, streamSSE } from '../..//src/helper/streaming'
 import { serveStatic, toSSG } from '../../src/adapter/bun'
 import { createBunWebSocket } from '../../src/adapter/bun/websocket'
@@ -11,7 +13,6 @@ import { Hono } from '../../src/index'
 import { jsx } from '../../src/jsx'
 import { basicAuth } from '../../src/middleware/basic-auth'
 import { jwt } from '../../src/middleware/jwt'
-import { HonoRequest } from '../../src/request'
 
 // Test just only minimal patterns.
 // Because others are tested well in Cloudflare Workers environment already.
@@ -42,7 +43,7 @@ describe('Basic', () => {
 
 describe('Environment Variables', () => {
   it('Should return the environment variable', async () => {
-    const c = new Context(new HonoRequest(new Request('http://localhost/')))
+    const c = new Context(new Request('http://localhost/'))
     const { NAME } = env<{ NAME: string }>(c)
     expect(NAME).toBe('Bun')
   })
@@ -107,6 +108,8 @@ describe('Serve Static Middleware', () => {
     })
   )
 
+  app.all('/static-absolute-root/*', serveStatic({ root: path.dirname(__filename) }))
+
   beforeEach(() => onNotFound.mockClear())
 
   it('Should return static file correctly', async () => {
@@ -157,6 +160,13 @@ describe('Serve Static Middleware', () => {
     expect(res.status).toBe(200)
     expect(await res.text()).toBe('Hi\n')
   })
+
+  it('Should return 200 response - /static-absolute-root/plain.txt', async () => {
+    const res = await app.request('http://localhost/static-absolute-root/plain.txt')
+    expect(res.status).toBe(200)
+    expect(await res.text()).toBe('Bun!')
+    expect(onNotFound).not.toHaveBeenCalled()
+  })
 })
 
 // Bun support WebCrypto since v0.2.2
@@ -310,8 +320,6 @@ describe('WebSockets Helper', () => {
     expect(receivedMessage).toBe(message)
   })
 })
-const fs = require('fs').promises
-const path = require('path')
 
 async function deleteDirectory(dirPath) {
   if (

runtime-tests/bun/static-absolute-root/plain.txt

@@ -0,0 +1 @@
+Bun!

runtime-tests/deno/.vscode/settings.json

@@ -1,7 +1,7 @@
 {
   "eslint.validate": ["javascript", "javascriptreact", "typescript", "typescriptreact"],
   "editor.codeActionsOnSave": {
-    "source.fixAll.eslint": true
+    "source.fixAll.eslint": "explicit"
   },
   "deno.enable": true
 }

runtime-tests/deno/deno.json

@@ -13,7 +13,8 @@
   ],
   "imports": {
     "@std/assert": "jsr:@std/assert@^1.0.3",
+    "@std/path": "jsr:@std/path@^1.0.3",
     "@std/testing": "jsr:@std/testing@^1.0.1",
     "hono/jsx/jsx-runtime": "../../src/jsx/jsx-runtime.ts"
   }
-}
+}

runtime-tests/deno/middleware.test.tsx

@@ -1,4 +1,5 @@
 import { assertEquals, assertMatch } from '@std/assert'
+import { dirname, fromFileUrl } from '@std/path'
 import { assertSpyCall, assertSpyCalls, spy } from '@std/testing/mock'
 import { serveStatic } from '../../src/adapter/deno/index.ts'
 import { Hono } from '../../src/hono.ts'
@@ -94,6 +95,16 @@ Deno.test('Serve Static middleware', async () => {
     })
   )
 
+  app.get('/static-absolute-root/*', serveStatic({ root: dirname(fromFileUrl(import.meta.url)) }))
+
+  app.get(
+    '/static/*',
+    serveStatic({
+      root: './runtime-tests/deno',
+      onNotFound,
+    })
+  )
+
   let res = await app.request('http://localhost/favicon.ico')
   assertEquals(res.status, 200)
   assertEquals(res.headers.get('Content-Type'), 'image/x-icon')
@@ -132,6 +143,10 @@ Deno.test('Serve Static middleware', async () => {
   res = await app.request('http://localhost/static/hello.world')
   assertEquals(res.status, 200)
   assertEquals(await res.text(), 'Hi\n')
+
+  res = await app.request('http://localhost/static-absolute-root/plain.txt')
+  assertEquals(res.status, 200)
+  assertEquals(await res.text(), 'Deno!')
 })
 
 Deno.test('JWT Authentication middleware', async () => {

runtime-tests/deno/static-absolute-root/plain.txt

@@ -0,0 +1 @@
+Deno!

src/adapter/bun/serve-static.ts

@@ -9,13 +9,13 @@ export const serveStatic = <E extends Env = Env>(
 ): MiddlewareHandler => {
   return async function serveStatic(c, next) {
     const getContent = async (path: string) => {
-      path = `./${path}`
+      path = path.startsWith('/') ? path : `./${path}`
       // @ts-ignore
       const file = Bun.file(path)
       return (await file.exists()) ? file : null
     }
     const pathResolve = (path: string) => {
-      return `./${path}`
+      return path.startsWith('/') ? path : `./${path}`
     }
     const isDir = async (path: string) => {
       let isDir

src/adapter/deno/serve-static.ts

@@ -20,7 +20,7 @@ export const serveStatic = <E extends Env = Env>(
       }
     }
     const pathResolve = (path: string) => {
-      return `./${path}`
+      return path.startsWith('/') ? path : `./${path}`
     }
     const isDir = (path: string) => {
       let isDir

src/middleware/serve-static/index.test.ts

@@ -226,4 +226,62 @@ describe('Serve Static Middleware', () => {
     expect(res.status).toBe(200)
     expect(res.body).toBe(body)
   })
+
+  describe('Changing root path', () => {
+    const pathResolve = (path: string) => {
+      return path.startsWith('/') ? path : `./${path}`
+    }
+
+    it('Should return the content with absolute root path', async () => {
+      const app = new Hono()
+      const serveStatic = baseServeStatic({
+        getContent,
+        pathResolve,
+        root: '/home/hono/child',
+      })
+      app.get('/static/*', serveStatic)
+
+      const res = await app.request('/static/html/hello.html')
+      expect(await res.text()).toBe('Hello in /home/hono/child/static/html/hello.html')
+    })
+
+    it('Should traverse the directories with absolute root path', async () => {
+      const app = new Hono()
+      const serveStatic = baseServeStatic({
+        getContent,
+        pathResolve,
+        root: '/home/hono/../parent',
+      })
+      app.get('/static/*', serveStatic)
+
+      const res = await app.request('/static/html/hello.html')
+      expect(await res.text()).toBe('Hello in /home/parent/static/html/hello.html')
+    })
+
+    it('Should treat the root path includes .. as relative path', async () => {
+      const app = new Hono()
+      const serveStatic = baseServeStatic({
+        getContent,
+        pathResolve,
+        root: '../home/hono',
+      })
+      app.get('/static/*', serveStatic)
+
+      const res = await app.request('/static/html/hello.html')
+      expect(await res.text()).toBe('Hello in ./../home/hono/static/html/hello.html')
+    })
+
+    it('Should not allow directory traversal with . as relative path', async () => {
+      const app = new Hono()
+      const serveStatic = baseServeStatic({
+        getContent,
+        pathResolve,
+        root: '.',
+      })
+      app.get('*', serveStatic)
+
+      const res = await app.request('///etc/passwd')
+      expect(res.status).toBe(404)
+    })
+  })
 })

src/middleware/serve-static/index.ts

@@ -39,6 +39,18 @@ export const serveStatic = <E extends Env = Env>(
     isDir?: (path: string) => boolean | undefined | Promise<boolean | undefined>
   }
 ): MiddlewareHandler => {
+  let isAbsoluteRoot = false
+  let root: string
+
+  if (options.root) {
+    if (options.root.startsWith('/')) {
+      isAbsoluteRoot = true
+      root = new URL(`file://${options.root}`).pathname
+    } else {
+      root = options.root
+    }
+  }
+
   return async (c, next) => {
     // Do nothing if Response is already set
     if (c.finalized) {
@@ -48,7 +60,6 @@ export const serveStatic = <E extends Env = Env>(
 
     let filename = options.path ?? decodeURI(c.req.path)
     filename = options.rewriteRequestPath ? options.rewriteRequestPath(filename) : filename
-    const root = options.root
 
     // If it was Directory, force `/` on the end.
     if (!filename.endsWith('/') && options.isDir) {
@@ -71,6 +82,10 @@ export const serveStatic = <E extends Env = Env>(
       return await next()
     }
 
+    if (isAbsoluteRoot) {
+      path = '/' + path
+    }
+
     const getContent = options.getContent
     const pathResolve = options.pathResolve ?? defaultPathResolve
     path = pathResolve(path)

src/utils/filepath.ts

@@ -52,5 +52,9 @@ export const getFilePathWithoutDefaultDocument = (
   let path = root ? root + '/' + filename : filename
   path = path.replace(/^\.?\//, '')
 
+  if (root[0] !== '/' && path[0] === '/') {
+    return
+  }
+
   return path
 }