add express-session instrumentation

packages/datadog-instrumentations/src/express-session.js

@@ -0,0 +1,41 @@
+'use strict'
+
+const shimmer = require('../../datadog-shimmer')
+const { channel, addHook } = require('./helpers/instrument')
+
+const sessionMiddlewareFinishCh = channel('datadog:express-session:middleware:finish')
+
+function wrapSessionMiddleware (sessionMiddleware) {
+  return function wrappedSessionMiddleware (req, res, next) {
+    shimmer.wrap(arguments, 2, function wrapNext (next) {
+      return function wrappedNext () {
+        if (sessionMiddlewareFinishCh.hasSubscribers) {
+          const abortController = new AbortController()
+
+          sessionMiddlewareFinishCh.publish({ req, res, sessionId: req.sessionID, abortController })
+
+          if (abortController.signal.aborted) return
+        }
+
+        return next.apply(this, arguments)
+      }
+    })
+
+    return sessionMiddleware.apply(this, arguments)
+  }
+}
+
+function wrapSession (session) {
+  return function wrappedSession () {
+    const sessionMiddleware = session.apply(this, arguments)
+
+    return shimmer.wrapFunction(sessionMiddleware, wrapSessionMiddleware)
+  }
+}
+
+addHook({
+  name: 'express-session',
+  versions: ['>=1.0.1']
+}, session => {
+  return shimmer.wrapFunction(session, wrapSession)
+})

packages/datadog-instrumentations/src/helpers/hooks.js

@@ -47,6 +47,7 @@ module.exports = {
   elasticsearch: () => require('../elasticsearch'),
   express: () => require('../express'),
   'express-mongo-sanitize': () => require('../express-mongo-sanitize'),
+  'express-session': () => require('../express-session'),
   fastify: () => require('../fastify'),
   'find-my-way': () => require('../find-my-way'),
   fs: () => require('../fs'),

packages/dd-trace/src/appsec/addresses.js

@@ -22,6 +22,7 @@ module.exports = {
 
   USER_ID: 'usr.id',
   USER_LOGIN: 'usr.login',
+  USER_SESSION_ID: 'usr.session_id',
 
   WAF_CONTEXT_PROCESSOR: 'waf.context.processor',
 

packages/dd-trace/src/appsec/channels.js

@@ -15,6 +15,7 @@ module.exports = {
   incomingHttpRequestEnd: dc.channel('dd-trace:incomingHttpRequestEnd'),
   passportVerify: dc.channel('datadog:passport:verify:finish'),
   passportUser: dc.channel('datadog:passport:deserializeUser:finish'),
+  expressSession: dc.channel('datadog:express-session:middleware:finish'),
   queryParser: dc.channel('datadog:query:read:finish'),
   setCookieChannel: dc.channel('datadog:iast:set-cookie'),
   nextBodyParsed: dc.channel('apm:next:body-parsed'),

packages/dd-trace/src/appsec/index.js

@@ -11,6 +11,7 @@ const {
   incomingHttpRequestEnd,
   passportVerify,
   passportUser,
+  expressSession,
   queryParser,
   nextBodyParsed,
   nextQueryParsed,
@@ -69,6 +70,7 @@ function enable (_config) {
     incomingHttpRequestEnd.subscribe(incomingHttpEndTranslator)
     passportVerify.subscribe(onPassportVerify) // possible optimization: only subscribe if collection mode is enabled
     passportUser.subscribe(onPassportDeserializeUser)
+    expressSession.subscribe(onExpressSession)
     queryParser.subscribe(onRequestQueryParsed)
     nextBodyParsed.subscribe(onRequestBodyParsed)
     nextQueryParsed.subscribe(onRequestQueryParsed)
@@ -213,6 +215,23 @@ function onPassportDeserializeUser ({ user, abortController }) {
   handleResults(results, store.req, store.req.res, rootSpan, abortController)
 }
 
+function onExpressSession ({ req, res, sessionId, abortController }) {
+  const rootSpan = web.root(req)
+  if (!rootSpan) {
+    log.warn('[ASM] No rootSpan found in onExpressSession')
+    return
+  }
+
+  // do not call this if the SDK already called it
+  const results = waf.run({
+    persistent: {
+      [addresses.USER_SESSION_ID]: sessionId
+    }
+  }, req)
+
+  handleResults(results, req, res, rootSpan, abortController)
+}
+
 function onRequestQueryParsed ({ req, res, query, abortController }) {
   if (!query || typeof query !== 'object') return
 
@@ -327,6 +346,7 @@ function disable () {
   if (incomingHttpRequestEnd.hasSubscribers) incomingHttpRequestEnd.unsubscribe(incomingHttpEndTranslator)
   if (passportVerify.hasSubscribers) passportVerify.unsubscribe(onPassportVerify)
   if (passportUser.hasSubscribers) passportUser.unsubscribe(onPassportDeserializeUser)
+  if (expressSession.hasSubscribers) expressSession.unsubscribe(onExpressSession)
   if (queryParser.hasSubscribers) queryParser.unsubscribe(onRequestQueryParsed)
   if (nextBodyParsed.hasSubscribers) nextBodyParsed.unsubscribe(onRequestBodyParsed)
   if (nextQueryParsed.hasSubscribers) nextQueryParsed.unsubscribe(onRequestQueryParsed)

packages/dd-trace/src/appsec/remote_config/capabilities.js

@@ -24,6 +24,7 @@ module.exports = {
   APM_TRACING_SAMPLE_RULES: 1n << 29n,
   ASM_AUTO_USER_INSTRUM_MODE: 1n << 31n,
   ASM_ENDPOINT_FINGERPRINT: 1n << 32n,
+  ASM_SESSION_FINGERPRINT: 1n << 33n, // should we only send this if app uses express-session ?
   ASM_NETWORK_FINGERPRINT: 1n << 34n,
   ASM_HEADER_FINGERPRINT: 1n << 35n,
   ASM_RASP_CMDI: 1n << 37n

packages/dd-trace/src/appsec/sdk/set_user.js

@@ -23,6 +23,10 @@
     return
   }
 
+  if (user.session_id && typeof user.session_id === 'string') {
+    persistent['usr.session_id'] = user.session_id
+  }
+
   setUserTags(user, rootSpan)
   rootSpan.setTag('_dd.appsec.user.collection_mode', 'sdk')