feat: support x-forwarded-path (#579)

Author: fenos

src/config.ts

@@ -56,6 +56,7 @@ type StorageConfigType = {
   tenantId: string
   requestUrlLengthLimit: number
   requestXForwardedHostRegExp?: string
+  requestAllowXForwardedPrefix?: boolean
   logLevel?: string
   logflareEnabled?: boolean
   logflareApiKey?: string
@@ -194,6 +195,8 @@ export function getConfig(options?: { reload?: boolean }): StorageConfigType {
       'REQUEST_X_FORWARDED_HOST_REGEXP',
       'X_FORWARDED_HOST_REGEXP'
     ),
+    requestAllowXForwardedPrefix:
+      getOptionalConfigFromEnv('REQUEST_ALLOW_X_FORWARDED_PATH') === 'true',
     requestUrlLengthLimit:
       Number(getOptionalConfigFromEnv('REQUEST_URL_LENGTH_LIMIT', 'URL_LENGTH_LIMIT')) || 7_500,
     requestTraceHeader: getOptionalConfigFromEnv('REQUEST_TRACE_HEADER', 'REQUEST_ID_HEADER'),

src/http/plugins/signature-v4.ts

@@ -14,6 +14,7 @@ const {
   serviceKey,
   storageS3Region,
   isMultitenant,
+  requestAllowXForwardedPrefix,
   s3ProtocolPrefix,
   s3ProtocolAllowForwardedHeader,
   s3ProtocolEnforceRegion,
@@ -37,13 +38,21 @@ export const signatureV4 = fastifyPlugin(
         token,
       } = await createServerSignature(request.tenantId, clientSignature)
 
+      let storagePrefix = s3ProtocolPrefix
+      if (
+        requestAllowXForwardedPrefix &&
+        typeof request.headers['x-forwarded-prefix'] === 'string'
+      ) {
+        storagePrefix = request.headers['x-forwarded-prefix']
+      }
+
       const isVerified = signatureV4.verify(clientSignature, {
         url: request.url,
         body: request.body as string | ReadableStream | Buffer,
         headers: request.headers as Record<string, string | string[]>,
         method: request.method,
         query: request.query as Record<string, string>,
-        prefix: s3ProtocolPrefix,
+        prefix: storagePrefix,
       })
 
       if (!isVerified && !sessionToken) {

src/http/routes/tus/lifecycle.ts

@@ -10,7 +10,7 @@ import { UploadId } from '@storage/protocols/tus'
 
 import { getConfig } from '../../../config'
 
-const { storageS3Bucket, tusPath } = getConfig()
+const { storageS3Bucket, tusPath, requestAllowXForwardedPrefix } = getConfig()
 const reExtractFileID = /([^/]+)\/?$/
 
 export const SIGNED_URL_SUFFIX = '/sign'
@@ -92,8 +92,15 @@ export function generateUrl(
   }
   proto = process.env.NODE_ENV === 'production' ? 'https' : proto
 
+  let basePath = path
+
+  const forwardedPath = req.headers['x-forwarded-prefix']
+  if (requestAllowXForwardedPrefix && typeof forwardedPath === 'string') {
+    basePath = forwardedPath + path
+  }
+
   const isSigned = req.url?.endsWith(SIGNED_URL_SUFFIX)
-  const fullPath = isSigned ? `${path}${SIGNED_URL_SUFFIX}` : path
+  const fullPath = isSigned ? `${basePath}${SIGNED_URL_SUFFIX}` : basePath
 
   if (req.headers['x-forwarded-host']) {
     const port = req.headers['x-forwarded-port']

src/internal/monitoring/logger.ts

@@ -139,6 +139,7 @@ const whitelistHeaders = (headers: Record<string, unknown>) => {
     'x-forwarded-proto',
     'x-forwarded-host',
     'x-forwarded-port',
+    'x-forwarded-prefix',
     'referer',
     'content-length',
     'x-real-ip',

src/storage/protocols/s3/signature-v4.ts

@@ -184,7 +184,7 @@ export class SignatureV4 {
     const serverSignature = this.sign(clientSignature, request)
     return crypto.timingSafeEqual(
       Buffer.from(clientSignature.signature),
-      Buffer.from(serverSignature)
+      Buffer.from(serverSignature.signature)
     )
   }
 
@@ -223,7 +223,7 @@ export class SignatureV4 {
       serverCredentials.service
     )
 
-    return this.hmac(signingKey, stringToSign).toString('hex')
+    return { signature: this.hmac(signingKey, stringToSign).toString('hex'), canonicalRequest }
   }
 
   protected getPayloadHash(clientSignature: ClientSignature, request: SignatureRequest) {