Re-merge of PR #150: Support accepting multiple public keys

README.md

@@ -155,20 +155,27 @@ publicKey=example_key
 
 * **publicKey** - this is the public key used to verify the cookie
 
-### Generating Keys
+### Rotating Keys
 
-**Guardian Devs**: See the [Emergency Panda key-rotation Guide](https://docs.google.com/document/d/1haVnQ9D8zNYUU-fOfkudPC1WpPGrlelLygd8V7xb3eQ/edit?usp=sharing).
+**Guardian Devs**: See the [Panda key-rotation Guide](https://docs.google.com/document/d/1haVnQ9D8zNYUU-fOfkudPC1WpPGrlelLygd8V7xb3eQ/edit?usp=sharing)
+for Guardian-specific details of where config details are stored, etc.
 
-You can generate an rsa key pair as follows:
+To avoid disruption to users, rotating keys requires 3 distinct settings updates, with pauses between each one. First
+obtain a copy of the current settings file (eg `current-from-s3.settings`), then use the sbt console to run
+the `CryptoConfForRotation` Scala script on that `.settings` file to generate a new RSA 4096 keypair and the new
+required config files for each step:
 
-    openssl genrsa -out private_key.pem 4096
-    openssl rsa -pubout -in private_key.pem -out public_key.pem
-
-There is a helper script in the root of this project that uses the commands above and outputs a new keypair in the format used by the panda settings file:
+```
+pan-domain-auth-verification / Test / runMain com.gu.pandomainauth.CryptoConfForRotation current-from-s3.settings
+```
 
-    ./generateKeyPair.sh
+3 new partial `.settings` files will be created, providing _just_ the updated crypto settings - you'll need to
+edit them into the existing `current-from-s3.settings` & `current-from-s3.settings.public` files before uploading
+those updates:
 
-Note: you only need to pass the key ie the blob of base64 between the start and end markers in the pem file.
+* 1.rotation-upcoming.settings - give this 2 minutes of settling time 
+* 2.rotation-in-progress.settings - give this at least 1 hour of settling time
+* 3.rotation-complete.settings
 
 ## Integrating with your Scala app
 

build.sbt

@@ -22,7 +22,7 @@ val commonSettings =
       "-deprecation",
       // upgrade warnings to errors except deprecations
       "-Wconf:cat=deprecation:ws,any:e",
-      "-release:8"
+      "-release:11"
     ),
     licenses := Seq(License.Apache2),
   )

pan-domain-auth-core/src/main/scala/com/gu/pandomainauth/PanDomainAuthSettingsRefresher.scala

@@ -35,9 +35,10 @@ class PanDomainAuthSettingsRefresher(
   private val settingsRefresher = new Settings.Refresher[PanDomainAuthSettings](
     new Settings.Loader(s3BucketLoader, settingsFileKey),
     PanDomainAuthSettings.apply,
+    _.signingAndVerification,
     scheduler
   )
-  settingsRefresher.start(1)
+  settingsRefresher.start()
 
   def settings: PanDomainAuthSettings = settingsRefresher.get()
 }

pan-domain-auth-core/src/main/scala/com/gu/pandomainauth/model/PanDomainAuthSettings.scala

@@ -1,10 +1,11 @@
 package com.gu.pandomainauth.model
 
-import com.gu.pandomainauth.SettingsFailure.SettingsResult
-import com.gu.pandomainauth.service.{CryptoConf, KeyPair}
+import com.gu.pandomainauth.Settings.SettingsResult
+import com.gu.pandomainauth.service.CryptoConf
+import com.gu.pandomainauth.service.CryptoConf.SigningAndVerification
 
 case class PanDomainAuthSettings(
-  signingKeyPair: KeyPair,
+  signingAndVerification: SigningAndVerification,
   cookieSettings: CookieSettings,
   oAuthSettings: OAuthSettings,
   google2FAGroupSettings: Option[Google2FAGroupSettings]
@@ -51,9 +52,9 @@ object PanDomainAuthSettings{
     ) yield Google2FAGroupSettings(serviceAccountId, serviceAccountCert, adminUser, group)
 
     for {
-      activeKeyPair <- CryptoConf.SettingsReader(settingMap).activeKeyPair
+      cryptoConf <- CryptoConf.SettingsReader(settingMap).signingAndVerificationConf
     } yield PanDomainAuthSettings(
-      activeKeyPair,
+      cryptoConf,
       cookieSettings,
       oAuthSettings,
       google2faSettings

pan-domain-auth-example/app/VerifyExample.scala

@@ -3,6 +3,7 @@ import com.amazonaws.regions.Regions
 import com.amazonaws.services.s3.AmazonS3ClientBuilder
 import com.gu.pandomainauth.S3BucketLoader.forAwsSdkV1
 import com.gu.pandomainauth.model.{Authenticated, AuthenticatedUser, GracePeriod}
+import com.gu.pandomainauth.service.CryptoConf
 import com.gu.pandomainauth.{PanDomain, PublicSettings, Settings}
 
 object VerifyExample {
@@ -21,7 +22,7 @@ object VerifyExample {
   // Call the start method when your application starts up to ensure the settings are kept up to date
   publicSettings.start()
 
-  val publicKey = publicSettings.publicKey
+  val verification: CryptoConf.Verification = publicSettings.verification
 
   // The name of this particular application
   val system = "test"
@@ -42,7 +43,7 @@ object VerifyExample {
   val cacheValidation = false
 
   // To verify, call the authStatus method with the encoded cookie data
-  val status = PanDomain.authStatus("<<cookie data>>>", publicKey, validateUser, apiGracePeriod, system, cacheValidation, forceExpiry = false)
+  val status = PanDomain.authStatus("<<cookie data>>>", verification, validateUser, apiGracePeriod, system, cacheValidation, forceExpiry = false)
 
   status match {
     case Authenticated(_) | GracePeriod(_) =>

pan-domain-auth-play/src/main/scala/com/gu/pandomainauth/action/Actions.scala

@@ -8,9 +8,8 @@ import play.api.libs.ws.WSClient
 import play.api.mvc.Results._
 import play.api.mvc._
 
+import java.net.{URLDecoder, URLEncoder}
 import scala.concurrent.{ExecutionContext, Future}
-import java.net.URLEncoder
-import java.net.URLDecoder
 
 class UserRequest[A](val user: User, request: Request[A]) extends WrappedRequest[A](request)
 
@@ -198,7 +197,7 @@ trait AuthActions {
   }
 
   def readAuthenticatedUser(request: RequestHeader): Option[AuthenticatedUser] = readCookie(request) flatMap { cookie =>
-    CookieUtils.parseCookieData(cookie.cookie.value, settings.signingKeyPair.publicKey).toOption
+    CookieUtils.parseCookieData(cookie.cookie.value, settings.signingAndVerification).toOption
   }
 
   def readCookie(request: RequestHeader): Option[PandomainCookie] = {
@@ -208,14 +207,13 @@ trait AuthActions {
     }
   }
 
-  def generateCookie(authedUser: AuthenticatedUser): Cookie =
-    Cookie(
-      name = settings.cookieSettings.cookieName,
-      value = CookieUtils.generateCookieData(authedUser, settings.signingKeyPair.privateKey),
-      domain = Some(domain),
-      secure = true,
-      httpOnly = true
-    )
+  def generateCookie(authedUser: AuthenticatedUser): Cookie = Cookie(
+    name = settings.cookieSettings.cookieName,
+    value = CookieUtils.generateCookieData(authedUser, settings.signingAndVerification),
+    domain = Some(domain),
+    secure = true,
+    httpOnly = true
+  )
 
   def includeSystemInCookie(authedUser: AuthenticatedUser)(result: Result): Result = {
     val updatedAuth    = authedUser.copy(authenticatedIn = authedUser.authenticatedIn + system)
@@ -237,7 +235,7 @@ trait AuthActions {
     */
   def extractAuth(request: RequestHeader): AuthenticationStatus = {
     readCookie(request).map { cookie =>
-      PanDomain.authStatus(cookie.cookie.value, settings.signingKeyPair.publicKey, validateUser, apiGracePeriod, system, cacheValidation, cookie.forceExpiry)
+      PanDomain.authStatus(cookie.cookie.value, settings.signingAndVerification, validateUser, apiGracePeriod, system, cacheValidation, cookie.forceExpiry)
     } getOrElse NotAuthenticated
   }
 

pan-domain-auth-verification/src/main/scala/com/gu/pandomainauth/PanDomain.scala

@@ -2,17 +2,16 @@ package com.gu.pandomainauth
 
 import com.gu.pandomainauth.model._
 import com.gu.pandomainauth.service.CookieUtils
-
-import java.security.PublicKey
+import com.gu.pandomainauth.service.CryptoConf.Verification
 
 
 object PanDomain {
   /**
    * Check the authentication status of the provided credentials by examining the signed cookie data.
    */
-  def authStatus(cookieData: String, publicKey: PublicKey, validateUser: AuthenticatedUser => Boolean,
+  def authStatus(cookieData: String, verification: Verification, validateUser: AuthenticatedUser => Boolean,
                  apiGracePeriod: Long, system: String, cacheValidation: Boolean, forceExpiry: Boolean): AuthenticationStatus = {
-    CookieUtils.parseCookieData(cookieData, publicKey).fold(InvalidCookie, { authedUser =>
+    CookieUtils.parseCookieData(cookieData, verification).fold(InvalidCookie, { authedUser =>
       checkStatus(authedUser, validateUser, apiGracePeriod, system, cacheValidation, forceExpiry)
     })
   }

pan-domain-auth-verification/src/main/scala/com/gu/pandomainauth/PublicSettings.scala

@@ -1,14 +1,15 @@
 package com.gu.pandomainauth
 
 import com.amazonaws.services.s3.AmazonS3
-import com.gu.pandomainauth.Settings.Loader
-import com.gu.pandomainauth.SettingsFailure.SettingsResult
+import com.gu.pandomainauth.Settings.{Loader, SettingsResult}
 import com.gu.pandomainauth.service.CryptoConf
+import com.gu.pandomainauth.service.CryptoConf.Verification
 
 import java.security.PublicKey
+import java.time.Duration
+import java.time.Duration.ofMinutes
 import java.util.concurrent.Executors.newScheduledThreadPool
 import java.util.concurrent.{Executors, ScheduledExecutorService}
-import scala.concurrent.duration._
 
 /**
  * Class that contains the static public settings and includes mechanism for fetching the public key. Once you have an
@@ -21,15 +22,19 @@ class PublicSettings(loader: Settings.Loader, scheduler: ScheduledExecutorServic
     new Settings.Loader(S3BucketLoader.forAwsSdkV1(s3Client, bucketName), settingsFileKey), scheduler
   )
 
-  private val settingsRefresher = new Settings.Refresher[PublicKey](
+  private val settingsRefresher = new Settings.Refresher[Verification](
     loader,
-    CryptoConf.SettingsReader(_).activePublicKey,
+    CryptoConf.SettingsReader(_).verificationConf,
+    identity,
     scheduler
   )
 
-  def start(interval: FiniteDuration = 60.seconds): Unit = settingsRefresher.start(interval.toMinutes.toInt)
+  def start(interval: Duration = ofMinutes(1)): Unit = settingsRefresher.start(interval)
 
-  def publicKey: PublicKey = settingsRefresher.get()
+  def verification: Verification = settingsRefresher.get()
+
+  @deprecated("Use `verification` instead, to allow smooth transition to new public keys")
+  def publicKey: PublicKey = verification.activePublicKey
 }
 
 /**
@@ -40,11 +45,6 @@ object PublicSettings {
 
   def apply(loader: Settings.Loader): PublicSettings = new PublicSettings(loader, newScheduledThreadPool(1))
 
-  /**
-   * Fetches the public key from the public S3 bucket
-   *
-   * @param domain the domain to fetch the public key for
-   */
-  def getPublicKey(loader: Loader): SettingsResult[PublicKey] =
-    loader.loadAndParseSettingsMap().flatMap(CryptoConf.SettingsReader(_).activePublicKey)
+  def getVerification(loader: Loader): SettingsResult[Verification] =
+    loader.loadAndParseSettingsMap().flatMap(CryptoConf.SettingsReader(_).verificationConf)
 }

pan-domain-auth-verification/src/main/scala/com/gu/pandomainauth/Settings.scala

@@ -1,12 +1,15 @@
 package com.gu.pandomainauth
 
 import com.amazonaws.util.IOUtils
-import com.gu.pandomainauth.SettingsFailure.SettingsResult
+import com.gu.pandomainauth.service.CryptoConf
+import com.gu.pandomainauth.service.CryptoConf.Verification
 import org.slf4j.{Logger, LoggerFactory}
 
 import java.io.ByteArrayInputStream
+import java.time.Duration
+import java.time.Duration.ofMinutes
 import java.util.Properties
-import java.util.concurrent.TimeUnit.MINUTES
+import java.util.concurrent.TimeUnit.MILLISECONDS
 import java.util.concurrent.atomic.AtomicReference
 import java.util.concurrent.{Executors, ScheduledExecutorService}
 import scala.jdk.CollectionConverters._
@@ -48,11 +51,15 @@ case object InvalidBase64 extends SettingsFailure {
   override val description: String = "Settings file value for cryptographic key is not valid base64"
 }
 
-object SettingsFailure {
+object Settings {
   type SettingsResult[A] = Either[SettingsFailure, A]
-}
 
-object Settings {
+  implicit class RichSettingsResultSeq[A](result: Seq[SettingsResult[A]]) {
+    def sequence: SettingsResult[Seq[A]] = result.foldLeft[SettingsResult[List[A]]](Right(Nil)) { // Easier with Cats!
+      (acc, e) => for (keys <- acc; key <- e) yield key :: keys
+    }
+  }
+
   /**
    * @param settingsFileKey the name of the file that contains the private settings for the given domain
    */
@@ -77,6 +84,7 @@ object Settings {
   class Refresher[A](
     loader: Settings.Loader,
     settingsParser: Map[String, String] => SettingsResult[A],
+    verificationIn: A => Verification,
     scheduler: ScheduledExecutorService = Executors.newScheduledThreadPool(1)
   ) {
     // This is deliberately designed to throw an exception during construction if we cannot immediately read the settings
@@ -86,15 +94,21 @@ object Settings {
 
     private val logger = LoggerFactory.getLogger(getClass)
 
-    def start(interval: Int): Unit = scheduler.scheduleAtFixedRate(() => refresh(), 0, interval, MINUTES)
+    def start(interval: Duration = ofMinutes(1)): Unit = {
+      logger.info(s"Starting refresh schedule with an interval of $interval")
+      scheduler.scheduleAtFixedRate(() => refresh(), 0, interval.toMillis, MILLISECONDS)
+    }
 
     def loadAndParseSettings(): SettingsResult[A] =
       loader.loadAndParseSettingsMap().flatMap(settingsParser)
 
     private def refresh(): Unit = loadAndParseSettings() match {
       case Right(newSettings) =>
         val oldSettings = store.getAndSet(newSettings)
-        if (oldSettings != newSettings) logger.info("Updated pan-domain settings")
+        for (change <- CryptoConf.Change.compare(verificationIn(oldSettings), verificationIn(newSettings))) {
+          val message = s"Panda settings changed: ${change.summary}"
+          if (change.isBreakingChange) logger.warn(message) else logger.info(message)
+        }
       case Left(err) =>
         logger.error("Failed to update pan-domain settings for $domain")
         err.logError(logger)

pan-domain-auth-verification/src/main/scala/com/gu/pandomainauth/service/CookieUtils.scala

@@ -2,8 +2,8 @@ package com.gu.pandomainauth.service
 
 import com.gu.pandomainauth.model.{AuthenticatedUser, User}
 import com.gu.pandomainauth.service.CookieUtils.CookieIntegrityFailure.{MalformedCookieText, MissingOrMalformedUserData, SignatureNotValid}
+import com.gu.pandomainauth.service.CryptoConf.{Signing, Verification}
 
-import java.security.{PrivateKey, PublicKey}
 import scala.util.Try
 
 object CookieUtils {
@@ -50,12 +50,12 @@ object CookieUtils {
     )
   }
 
-  def generateCookieData(authUser: AuthenticatedUser, prvKey: PrivateKey): String =
-    CookiePayload.generateForPayloadText(serializeAuthenticatedUser(authUser), prvKey).asCookieText
+  def generateCookieData(authUser: AuthenticatedUser, signing: Signing): String =
+    CookiePayload.generateForPayloadText(serializeAuthenticatedUser(authUser), signing.activePrivateKey).asCookieText
 
-  def parseCookieData(cookieString: String, publicKey: PublicKey): CookieResult[AuthenticatedUser] = for {
+  def parseCookieData(cookieString: String, verification: Verification): CookieResult[AuthenticatedUser] = for {
     cookiePayload <- CookiePayload.parse(cookieString).toRight(MalformedCookieText)
-    cookiePayloadText <- cookiePayload.payloadTextVerifiedSignedWith(publicKey).toRight(SignatureNotValid)
+    cookiePayloadText <- verification.decode(cookiePayload.payloadTextVerifiedSignedWith).toRight(SignatureNotValid)
     authUser <- deserializeAuthenticatedUser(cookiePayloadText).toRight(MissingOrMalformedUserData)
   } yield authUser
 }

pan-domain-auth-verification/src/main/scala/com/gu/pandomainauth/service/Crypto.scala

@@ -14,22 +14,21 @@ object Crypto {
    *
    * Note: you only need to pass the key ie the blob of base64 between the start and end markers in the pem file.
    */
-
   Security.addProvider(new BouncyCastleProvider())
 
-  val signatureAlgorithm: String = "SHA256withRSA"
   val keyFactory = KeyFactory.getInstance("RSA")
+  private def signatureInstance() = Signature.getInstance("SHA256withRSA", "BC")
 
   def signData(data: Array[Byte], prvKey: PrivateKey): Array[Byte] = {
-    val rsa = Signature.getInstance(signatureAlgorithm, "BC")
+    val rsa = signatureInstance()
     rsa.initSign(prvKey)
 
     rsa.update(data)
     rsa.sign()
   }
 
   def verifySignature(data: Array[Byte], signature: Array[Byte], pubKey: PublicKey) : Boolean = {
-    val rsa = Signature.getInstance(signatureAlgorithm, "BC")
+    val rsa = signatureInstance()
     rsa.initVerify(pubKey)
 
     rsa.update(data)