fix: only serve files under src (#195)

Author: sapphi-red

.changeset/long-pillows-arrive.md

@@ -0,0 +1,5 @@
+---
+'vite-plugin-static-copy': patch
+---
+
+Files not included in `src` was possible to acess with a crafted request. See [GHSA-pp7p-q8fx-2968](https://github.com/sapphi-red/vite-plugin-static-copy/security/advisories/GHSA-pp7p-q8fx-2968) for more details.

.gitignore

@@ -54,9 +54,6 @@ typings/
 # Yarn Integrity file
 .yarn-integrity
 
-# dotenv environment variables file
-.env
-
 # parcel-bundler cache (https://parceljs.org/)
 .cache
 

src/middleware.ts

@@ -18,7 +18,7 @@ import type {
   OutgoingHttpHeaders,
   ServerResponse
 } from 'node:http'
-import { join, resolve } from 'node:path'
+import { join, resolve, sep } from 'node:path'
 import type { FileMap } from './serve'
 import type { TransformOptionObject } from './options'
 import {
@@ -54,6 +54,13 @@ function shouldServeOverwriteCheck(
   return true
 }
 
+function isFileInside(filepath: string, srcBase: string) {
+  const srcBaseWithTrailingSlash = srcBase.endsWith(sep)
+    ? srcBase
+    : `${srcBase}${sep}`
+  return filepath.startsWith(srcBaseWithTrailingSlash)
+}
+
 function viaLocal(
   root: string,
   publicDir: string,
@@ -87,7 +94,13 @@ function viaLocal(
     if (!uri.startsWith(dir)) continue
 
     for (const val of vals) {
-      const filepath = resolve(root, val.src, uri.slice(dir.length))
+      const srcBase = resolve(root, val.src)
+      const filepath = resolve(srcBase, uri.slice(dir.length))
+      if (!isFileInside(filepath, srcBase)) {
+        // uri includes non-normalized `../`
+        return undefined
+      }
+
       const overwriteCheck = shouldServeOverwriteCheck(
         val.overwrite,
         filepath,

test/fixtures/.env

@@ -0,0 +1 @@
+SHOULD_BE_HIDDEN=PRIVATE

test/tests.test.ts

@@ -3,15 +3,24 @@ import type { PreviewServer, ViteDevServer } from 'vite'
 import { build, createServer, preview } from 'vite'
 import fetch from 'node-fetch'
 import { testcases } from './testcases'
-import { getConfig, loadFileContent, normalizeLineBreak } from './utils'
+import {
+  getConfig,
+  loadFileContent,
+  normalizeLineBreak,
+  sendRawRequest,
+} from './utils'
 import type { AddressInfo } from 'node:net'
 
+const constructUrl = (server: ViteDevServer | PreviewServer, path: string) => {
+  const port = (server.httpServer!.address() as AddressInfo).port
+  return `http://localhost:${port}${path}`
+}
+
 const fetchFromServer = async (
   server: ViteDevServer | PreviewServer,
   path: string
 ) => {
-  const port = (server.httpServer!.address() as AddressInfo).port
-  const url = `http://localhost:${port}${path}`
+  const url = constructUrl(server, path)
   const res = await fetch(url)
   return res
 }
@@ -95,6 +104,15 @@ describe('serve', () => {
       )
       expect(res.headers.get('Cross-Origin-Opener-Policy')).toBe('same-origin')
     })
+
+    test.concurrent('disallow path traversal with ../', async () => {
+      const res = await sendRawRequest(
+        constructUrl(server, '/'),
+        '/fixture1/foo.txt/../.env',
+      )
+      expect(res).not.toContain('SHOULD_BE_HIDDEN')
+      expect(res).toContain('HTTP/1.1 404 Not Found')
+    })
   })
 })
 

test/utils.ts

@@ -2,6 +2,7 @@ import { readFile } from 'node:fs/promises'
 import { fileURLToPath } from 'node:url'
 import type { InlineConfig } from 'vite'
 import { normalizePath } from 'vite'
+import net from 'node:net'
 
 export const root = new URL('./fixtures/', import.meta.url)
 
@@ -31,3 +32,38 @@ export const loadFileContent = async (
 
 export const normalizeLineBreak = (input: string) =>
   input.replace(/\r\n/g, '\n')
+
+export const sendRawRequest = async (
+  baseUrl: string,
+  requestTarget: string,
+) => {
+  return new Promise<string>((resolve, reject) => {
+    const parsedUrl = new URL(baseUrl)
+
+    const buf: Buffer[] = []
+    const client = net.createConnection(
+      { port: +parsedUrl.port, host: parsedUrl.hostname },
+      () => {
+        client.write(
+          [
+            `GET ${encodeURI(requestTarget)} HTTP/1.1`,
+            `Host: ${parsedUrl.host}`,
+            'Connection: Close',
+            '\r\n',
+          ].join('\r\n'),
+        )
+      },
+    )
+    client.on('data', (data) => {
+      buf.push(data)
+    })
+    client.on('end', (hadError: unknown) => {
+      if (!hadError) {
+        resolve(Buffer.concat(buf).toString())
+      }
+    })
+    client.on('error', (err) => {
+      reject(err)
+    })
+  })
+}