From 5b04b5ed3bf01357c1e51e5b390ea57f713da233 Mon Sep 17 00:00:00 2001
From: Niels Andriesse <andriesseniels@gmail.com>
Date: Tue, 24 Sep 2019 15:05:59 +1000
Subject: [PATCH] Further build out device link authorization

---
 Signal.xcodeproj/project.pbxproj              |  8 ++--
 .../src/Loki/Group Chat/GroupChatPoller.swift | 34 ++++++-------
 .../src/Loki/Group Chat/RSSFeedPoller.swift   | 26 +++++-----
 Signal/src/Loki/Onboarding/SeedVC.swift       |  4 +-
 .../Loki/Settings/DeviceLinkingModal.swift    | 13 ++++-
 .../Settings/DeviceLinkingModalDelegate.swift | 11 +++--
 .../Multi Device/DeviceLinkingSession.swift   | 48 +++++++++++++++----
 .../DeviceLinkingSessionDelegate.swift        |  4 +-
 .../Notification+DeviceLinking.swift          |  4 ++
 .../src/Messages/OWSMessageManager.m          |  7 +--
 10 files changed, 104 insertions(+), 55 deletions(-)
 create mode 100644 SignalServiceKit/src/Loki/API/Multi Device/Notification+DeviceLinking.swift

diff --git a/Signal.xcodeproj/project.pbxproj b/Signal.xcodeproj/project.pbxproj
index cd0322bd8..5574af731 100644
--- a/Signal.xcodeproj/project.pbxproj
+++ b/Signal.xcodeproj/project.pbxproj
@@ -570,12 +570,12 @@
 		B86BD08123399883000F5AE3 /* QRCodeModal.swift in Sources */ = {isa = PBXBuildFile; fileRef = B86BD08023399883000F5AE3 /* QRCodeModal.swift */; };
 		B86BD08423399ACF000F5AE3 /* Modal.swift in Sources */ = {isa = PBXBuildFile; fileRef = B86BD08323399ACF000F5AE3 /* Modal.swift */; };
 		B86BD08623399CEF000F5AE3 /* SeedModal.swift in Sources */ = {isa = PBXBuildFile; fileRef = B86BD08523399CEF000F5AE3 /* SeedModal.swift */; };
-		B86BD08C2339AE43000F5AE3 /* DeviceLinkingModalDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = B86BD08B2339AE43000F5AE3 /* DeviceLinkingModalDelegate.swift */; };
 		B885D5F4233491AB00EE0D8E /* DeviceLinkingModal.swift in Sources */ = {isa = PBXBuildFile; fileRef = B885D5F3233491AB00EE0D8E /* DeviceLinkingModal.swift */; };
 		B885D5F62334A32100EE0D8E /* UIView+Constraint.swift in Sources */ = {isa = PBXBuildFile; fileRef = B885D5F52334A32100EE0D8E /* UIView+Constraint.swift */; };
 		B891105C2320872800F15FCC /* GoogleService-Info.plist in Resources */ = {isa = PBXBuildFile; fileRef = B891105B2320872800F15FCC /* GoogleService-Info.plist */; };
 		B891105E2320872800F15FCC /* GoogleService-Info.plist in Resources */ = {isa = PBXBuildFile; fileRef = B891105B2320872800F15FCC /* GoogleService-Info.plist */; };
 		B891105F2320872800F15FCC /* GoogleService-Info.plist in Resources */ = {isa = PBXBuildFile; fileRef = B891105B2320872800F15FCC /* GoogleService-Info.plist */; };
+		B894D0712339D6F300B4D94D /* DeviceLinkingModalDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = B894D0702339D6F300B4D94D /* DeviceLinkingModalDelegate.swift */; };
 		B89841E322B7579F00B1BDC6 /* NewConversationVC.swift in Sources */ = {isa = PBXBuildFile; fileRef = B89841E222B7579F00B1BDC6 /* NewConversationVC.swift */; };
 		B90418E6183E9DD40038554A /* DateUtil.m in Sources */ = {isa = PBXBuildFile; fileRef = B90418E5183E9DD40038554A /* DateUtil.m */; };
 		B9EB5ABD1884C002007CBB57 /* MessageUI.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = B9EB5ABC1884C002007CBB57 /* MessageUI.framework */; };
@@ -1378,10 +1378,10 @@
 		B86BD08023399883000F5AE3 /* QRCodeModal.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = QRCodeModal.swift; sourceTree = "<group>"; };
 		B86BD08323399ACF000F5AE3 /* Modal.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Modal.swift; sourceTree = "<group>"; };
 		B86BD08523399CEF000F5AE3 /* SeedModal.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SeedModal.swift; sourceTree = "<group>"; };
-		B86BD08B2339AE43000F5AE3 /* DeviceLinkingModalDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DeviceLinkingModalDelegate.swift; sourceTree = "<group>"; };
 		B885D5F3233491AB00EE0D8E /* DeviceLinkingModal.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DeviceLinkingModal.swift; sourceTree = "<group>"; };
 		B885D5F52334A32100EE0D8E /* UIView+Constraint.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UIView+Constraint.swift"; sourceTree = "<group>"; };
 		B891105B2320872800F15FCC /* GoogleService-Info.plist */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.xml; path = "GoogleService-Info.plist"; sourceTree = "<group>"; };
+		B894D0702339D6F300B4D94D /* DeviceLinkingModalDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DeviceLinkingModalDelegate.swift; sourceTree = "<group>"; };
 		B89841E222B7579F00B1BDC6 /* NewConversationVC.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NewConversationVC.swift; sourceTree = "<group>"; };
 		B90418E4183E9DD40038554A /* DateUtil.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = DateUtil.h; sourceTree = "<group>"; };
 		B90418E5183E9DD40038554A /* DateUtil.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = DateUtil.m; sourceTree = "<group>"; };
@@ -2668,7 +2668,7 @@
 			isa = PBXGroup;
 			children = (
 				B885D5F3233491AB00EE0D8E /* DeviceLinkingModal.swift */,
-				B86BD08B2339AE43000F5AE3 /* DeviceLinkingModalDelegate.swift */,
+				B894D0702339D6F300B4D94D /* DeviceLinkingModalDelegate.swift */,
 				B86BD08023399883000F5AE3 /* QRCodeModal.swift */,
 				B86BD08523399CEF000F5AE3 /* SeedModal.swift */,
 			);
@@ -3913,7 +3913,7 @@
 				45E5A6991F61E6DE001E4A8A /* MarqueeLabel.swift in Sources */,
 				34D1F0B01F867BFC0066283D /* OWSSystemMessageCell.m in Sources */,
 				45A663C51F92EC760027B59E /* GroupTableViewCell.swift in Sources */,
-				B86BD08C2339AE43000F5AE3 /* DeviceLinkingModalDelegate.swift in Sources */,
+				B894D0712339D6F300B4D94D /* DeviceLinkingModalDelegate.swift in Sources */,
 				34CA631B2097806F00E526A0 /* OWSContactShareView.m in Sources */,
 				B86BD08423399ACF000F5AE3 /* Modal.swift in Sources */,
 				34D1F0861F8678AA0066283D /* ConversationViewController.m in Sources */,
diff --git a/Signal/src/Loki/Group Chat/GroupChatPoller.swift b/Signal/src/Loki/Group Chat/GroupChatPoller.swift
index d712c317c..fbaa3c136 100644
--- a/Signal/src/Loki/Group Chat/GroupChatPoller.swift	
+++ b/Signal/src/Loki/Group Chat/GroupChatPoller.swift	
@@ -51,32 +51,32 @@ public final class GroupChatPoller : NSObject {
             let cutoffIndex = senderHexEncodedPublicKey.index(endIndex, offsetBy: -8)
             let senderDisplayName = "\(message.displayName) (...\(senderHexEncodedPublicKey[cutoffIndex..<endIndex]))"
             let id = group.id.data(using: String.Encoding.utf8)!
-            let x1 = SSKProtoGroupContext.builder(id: id, type: .deliver)
-            x1.setName(group.displayName)
-            let x2 = SSKProtoDataMessage.builder()
-            x2.setTimestamp(message.timestamp)
-            x2.setGroup(try! x1.build())
+            let groupContext = SSKProtoGroupContext.builder(id: id, type: .deliver)
+            groupContext.setName(group.displayName)
+            let dataMessage = SSKProtoDataMessage.builder()
+            dataMessage.setTimestamp(message.timestamp)
+            dataMessage.setGroup(try! groupContext.build())
             if let quote = message.quote {
-                let x5 = SSKProtoDataMessageQuote.builder(id: quote.quotedMessageTimestamp, author: quote.quoteeHexEncodedPublicKey)
-                x5.setText(quote.quotedMessageBody)
-                x2.setQuote(try! x5.build())
+                let signalQuote = SSKProtoDataMessageQuote.builder(id: quote.quotedMessageTimestamp, author: quote.quoteeHexEncodedPublicKey)
+                signalQuote.setText(quote.quotedMessageBody)
+                dataMessage.setQuote(try! signalQuote.build())
             }
-            x2.setBody(message.body)
+            dataMessage.setBody(message.body)
             if let messageServerID = message.serverID {
                 let publicChatInfo = SSKProtoPublicChatInfo.builder()
                 publicChatInfo.setServerID(messageServerID)
-                x2.setPublicChatInfo(try! publicChatInfo.build())
+                dataMessage.setPublicChatInfo(try! publicChatInfo.build())
             }
-            let x3 = SSKProtoContent.builder()
-            x3.setDataMessage(try! x2.build())
-            let x4 = SSKProtoEnvelope.builder(type: .ciphertext, timestamp: message.timestamp)
-            x4.setSource(senderHexEncodedPublicKey)
-            x4.setSourceDevice(OWSDevicePrimaryDeviceId)
-            x4.setContent(try! x3.build().serializedData())
+            let content = SSKProtoContent.builder()
+            content.setDataMessage(try! dataMessage.build())
+            let envelope = SSKProtoEnvelope.builder(type: .ciphertext, timestamp: message.timestamp)
+            envelope.setSource(senderHexEncodedPublicKey)
+            envelope.setSourceDevice(OWSDevicePrimaryDeviceId)
+            envelope.setContent(try! content.build().serializedData())
             let storage = OWSPrimaryStorage.shared()
             storage.dbReadWriteConnection.readWrite { transaction in
                 transaction.setObject(senderDisplayName, forKey: senderHexEncodedPublicKey, inCollection: group.id)
-                SSKEnvironment.shared.messageManager.throws_processEnvelope(try! x4.build(), plaintextData: try! x3.build().serializedData(), wasReceivedByUD: false, transaction: transaction)
+                SSKEnvironment.shared.messageManager.throws_processEnvelope(try! envelope.build(), plaintextData: try! content.build().serializedData(), wasReceivedByUD: false, transaction: transaction)
             }
         }
         // Processing logic for outgoing messages
diff --git a/Signal/src/Loki/Group Chat/RSSFeedPoller.swift b/Signal/src/Loki/Group Chat/RSSFeedPoller.swift
index 56ef5756e..5636e1386 100644
--- a/Signal/src/Loki/Group Chat/RSSFeedPoller.swift	
+++ b/Signal/src/Loki/Group Chat/RSSFeedPoller.swift	
@@ -49,20 +49,20 @@ public final class RSSFeedPoller : NSObject {
                 let options = [ NSAttributedString.DocumentReadingOptionKey.documentType : NSAttributedString.DocumentType.html ]
                 guard let body = try? NSAttributedString(data: bodyAsData, options: options, documentAttributes: nil).string else { return }
                 let id = feed.id.data(using: String.Encoding.utf8)!
-                let x1 = SSKProtoGroupContext.builder(id: id, type: .deliver)
-                x1.setName(feed.displayName)
-                let x2 = SSKProtoDataMessage.builder()
-                x2.setTimestamp(timestamp)
-                x2.setGroup(try! x1.build())
-                x2.setBody(body)
-                let x3 = SSKProtoContent.builder()
-                x3.setDataMessage(try! x2.build())
-                let x4 = SSKProtoEnvelope.builder(type: .ciphertext, timestamp: timestamp)
-                x4.setSource(NSLocalizedString("Loki", comment: ""))
-                x4.setSourceDevice(OWSDevicePrimaryDeviceId)
-                x4.setContent(try! x3.build().serializedData())
+                let groupContext = SSKProtoGroupContext.builder(id: id, type: .deliver)
+                groupContext.setName(feed.displayName)
+                let dataMessage = SSKProtoDataMessage.builder()
+                dataMessage.setTimestamp(timestamp)
+                dataMessage.setGroup(try! groupContext.build())
+                dataMessage.setBody(body)
+                let content = SSKProtoContent.builder()
+                content.setDataMessage(try! dataMessage.build())
+                let envelope = SSKProtoEnvelope.builder(type: .ciphertext, timestamp: timestamp)
+                envelope.setSource(NSLocalizedString("Loki", comment: ""))
+                envelope.setSourceDevice(OWSDevicePrimaryDeviceId)
+                envelope.setContent(try! content.build().serializedData())
                 OWSPrimaryStorage.shared().dbReadWriteConnection.readWrite { transaction in
-                    SSKEnvironment.shared.messageManager.throws_processEnvelope(try! x4.build(), plaintextData: try! x3.build().serializedData(), wasReceivedByUD: false, transaction: transaction)
+                    SSKEnvironment.shared.messageManager.throws_processEnvelope(try! envelope.build(), plaintextData: try! content.build().serializedData(), wasReceivedByUD: false, transaction: transaction)
                 }
             }
         }
diff --git a/Signal/src/Loki/Onboarding/SeedVC.swift b/Signal/src/Loki/Onboarding/SeedVC.swift
index 46e7c0dd3..b9b30cec1 100644
--- a/Signal/src/Loki/Onboarding/SeedVC.swift
+++ b/Signal/src/Loki/Onboarding/SeedVC.swift
@@ -337,10 +337,10 @@ final class SeedVC : OnboardingBaseViewController, DeviceLinkingModalDelegate {
         case .link: Analytics.shared.track("Device Linked")
         }
         if mode == .link {
-            let masterHexEncodedPublicKey = masterHexEncodedPublicKeyTextField.text!.trimmingCharacters(in: CharacterSet.whitespaces)
             let deviceLinkingModal = DeviceLinkingModal(mode: .slave, delegate: self)
             deviceLinkingModal.modalPresentationStyle = .overFullScreen
             present(deviceLinkingModal, animated: true, completion: nil)
+            let masterHexEncodedPublicKey = masterHexEncodedPublicKeyTextField.text!.trimmingCharacters(in: CharacterSet.whitespaces)
             let thread = TSContactThread.getOrCreateThread(contactId: masterHexEncodedPublicKey)
             ThreadUtil.enqueueDeviceLinkingMessage(in: thread)
         } else {
@@ -348,7 +348,7 @@ final class SeedVC : OnboardingBaseViewController, DeviceLinkingModalDelegate {
         }
     }
     
-    func handleDeviceLinkingRequestAuthorized() {
+    func handleDeviceLinkAuthorized(_ deviceLink: DeviceLink) {
         TSAccountManager.sharedInstance().didRegister()
         UserDefaults.standard.set(true, forKey: "didUpdateForMainnet")
         onboardingController.verificationDidComplete(fromView: self)
diff --git a/Signal/src/Loki/Settings/DeviceLinkingModal.swift b/Signal/src/Loki/Settings/DeviceLinkingModal.swift
index 760251133..4631e1589 100644
--- a/Signal/src/Loki/Settings/DeviceLinkingModal.swift
+++ b/Signal/src/Loki/Settings/DeviceLinkingModal.swift
@@ -71,7 +71,10 @@ final class DeviceLinkingModal : Modal, DeviceLinkingSessionDelegate {
     
     override func viewDidLoad() {
         super.viewDidLoad()
-        let _ = DeviceLinkingSession.startListeningForLinkingRequests(with: self)
+        switch mode {
+        case .master: let _ = DeviceLinkingSession.startListeningForLinkingRequests(with: self)
+        case .slave: let _ = DeviceLinkingSession.startListeningForLinkingAuthorization(with: self)
+        }
     }
     
     override func populateContentView() {
@@ -107,6 +110,10 @@ final class DeviceLinkingModal : Modal, DeviceLinkingSessionDelegate {
         contentView.pin(.bottom, to: .bottom, of: stackView, withInset: 16)
     }
     
+    deinit {
+        NotificationCenter.default.removeObserver(self)
+    }
+    
     // MARK: Device Linking
     func requestUserAuthorization(for deviceLink: DeviceLink) {
         self.deviceLink = deviceLink
@@ -126,4 +133,8 @@ final class DeviceLinkingModal : Modal, DeviceLinkingSessionDelegate {
         // TODO: Send device link authorized message
         dismiss(animated: true, completion: nil)
     }
+    
+    func handleDeviceLinkAuthorized(_ deviceLink: DeviceLink) {
+        delegate?.handleDeviceLinkAuthorized(deviceLink)
+    }
 }
diff --git a/Signal/src/Loki/Settings/DeviceLinkingModalDelegate.swift b/Signal/src/Loki/Settings/DeviceLinkingModalDelegate.swift
index 984daf70b..54737b518 100644
--- a/Signal/src/Loki/Settings/DeviceLinkingModalDelegate.swift
+++ b/Signal/src/Loki/Settings/DeviceLinkingModalDelegate.swift
@@ -1,7 +1,10 @@
 
-@objc(LKDeviceLinkingModalDelegate)
-protocol DeviceLinkingModalDelegate {
+@objc protocol DeviceLinkingModalDelegate {
     
-    /// Provides an opportunity for the slave device to update its UI after the master device has authorized the device linking request.
-    func handleDeviceLinkingRequestAuthorized()
+    func handleDeviceLinkAuthorized(_ deviceLink: DeviceLink)
+}
+
+extension DeviceLinkingModalDelegate {
+    
+    func handleDeviceLinkAuthorized(_ deviceLink: DeviceLink) { /* Do nothing */ } 
 }
diff --git a/SignalServiceKit/src/Loki/API/Multi Device/DeviceLinkingSession.swift b/SignalServiceKit/src/Loki/API/Multi Device/DeviceLinkingSession.swift
index af8b5bf1a..564e857db 100644
--- a/SignalServiceKit/src/Loki/API/Multi Device/DeviceLinkingSession.swift	
+++ b/SignalServiceKit/src/Loki/API/Multi Device/DeviceLinkingSession.swift	
@@ -5,6 +5,7 @@ import PromiseKit
 public final class DeviceLinkingSession : NSObject {
     private let delegate: DeviceLinkingSessionDelegate
     @objc public var isListeningForLinkingRequests = false
+    @objc public var isListeningForLinkingAuthorization = false
     
     // MARK: Lifecycle
     @objc public static var current: DeviceLinkingSession?
@@ -21,28 +22,57 @@ public final class DeviceLinkingSession : NSObject {
         return session
     }
     
-    @objc public func processLinkingRequest(from slaveHexEncodedPublicKey: String, with slaveSignature: Data) {
-        guard isListeningForLinkingRequests else { return }
-        stopListeningForLinkingRequests()
-        let master = DeviceLink.Device(hexEncodedPublicKey: OWSIdentityManager.shared().identityKeyPair()!.hexEncodedPublicKey)
+    public static func startListeningForLinkingAuthorization(with delegate: DeviceLinkingSessionDelegate) -> DeviceLinkingSession {
+        let session = DeviceLinkingSession(delegate: delegate)
+        session.isListeningForLinkingAuthorization = true
+        DeviceLinkingSession.current = session
+        return session
+    }
+    
+    @objc public func processLinkingRequest(from slaveHexEncodedPublicKey: String, to masterHexEncodedPublicKey: String, with slaveSignature: Data) {
+        guard isListeningForLinkingRequests, masterHexEncodedPublicKey == OWSIdentityManager.shared().identityKeyPair()!.hexEncodedPublicKey else { return }
+        let master = DeviceLink.Device(hexEncodedPublicKey: masterHexEncodedPublicKey)
         let slave = DeviceLink.Device(hexEncodedPublicKey: slaveHexEncodedPublicKey, signature: slaveSignature)
         let deviceLink = DeviceLink(between: master, and: slave)
-        guard isValidLinkingRequest(deviceLink) else { return }
+        guard hasValidSlaveSignature(deviceLink) else { return }
         delegate.requestUserAuthorization(for: deviceLink)
     }
     
+    @objc public func processLinkingAuthorization(from masterHexEncodedPublicKey: String, for slaveHexEncodedPublicKey: String, masterSignature: Data, slaveSignature: Data) {
+        guard isListeningForLinkingAuthorization, slaveHexEncodedPublicKey == OWSIdentityManager.shared().identityKeyPair()!.hexEncodedPublicKey else { return }
+        let master = DeviceLink.Device(hexEncodedPublicKey: masterHexEncodedPublicKey, signature: masterSignature)
+        let slave = DeviceLink.Device(hexEncodedPublicKey: slaveHexEncodedPublicKey, signature: slaveSignature)
+        let deviceLink = DeviceLink(between: master, and: slave)
+        guard hasValidSlaveSignature(deviceLink) && hasValidMasterSignature(deviceLink) else { return }
+        delegate.handleDeviceLinkAuthorized(deviceLink)
+    }
+    
     public func stopListeningForLinkingRequests() {
         DeviceLinkingSession.current = nil
         isListeningForLinkingRequests = false
     }
     
+    public func stopListeningForLinkingAuthorization() {
+        DeviceLinkingSession.current = nil
+        isListeningForLinkingAuthorization = false
+    }
+    
     // MARK: Private API
-    private func isValidLinkingRequest(_ deviceLink: DeviceLink) -> Bool {
-        // When requesting a device link, the slave device signs the master device's public key. When authorizing
-        // a device link, the master device signs the slave device's public key.
-        let slaveSignature = deviceLink.slave.signature!
+    
+    // When requesting a device link, the slave device signs the master device's public key. When authorizing
+    // a device link, the master device signs the slave device's public key.
+    
+    private func hasValidSlaveSignature(_ deviceLink: DeviceLink) -> Bool {
+        guard let slaveSignature = deviceLink.slave.signature else { return false }
         let slavePublicKey = Data(hex: deviceLink.slave.hexEncodedPublicKey)
         let masterPublicKey = Data(hex: deviceLink.master.hexEncodedPublicKey)
         return (try? Ed25519.verifySignature(slaveSignature, publicKey: slavePublicKey, data: masterPublicKey)) ?? false
     }
+    
+    private func hasValidMasterSignature(_ deviceLink: DeviceLink) -> Bool {
+        guard let masterSignature = deviceLink.master.signature else { return false }
+        let slavePublicKey = Data(hex: deviceLink.slave.hexEncodedPublicKey)
+        let masterPublicKey = Data(hex: deviceLink.master.hexEncodedPublicKey)
+        return (try? Ed25519.verifySignature(masterSignature, publicKey: masterPublicKey, data: slavePublicKey)) ?? false
+    }
 }
diff --git a/SignalServiceKit/src/Loki/API/Multi Device/DeviceLinkingSessionDelegate.swift b/SignalServiceKit/src/Loki/API/Multi Device/DeviceLinkingSessionDelegate.swift
index bca2c4939..ab806251c 100644
--- a/SignalServiceKit/src/Loki/API/Multi Device/DeviceLinkingSessionDelegate.swift	
+++ b/SignalServiceKit/src/Loki/API/Multi Device/DeviceLinkingSessionDelegate.swift	
@@ -1,6 +1,6 @@
 
-@objc(LKDeviceLinkingSessionDelegate)
 public protocol DeviceLinkingSessionDelegate {
     
-    @objc func requestUserAuthorization(for deviceLink: DeviceLink)
+    func requestUserAuthorization(for deviceLink: DeviceLink)
+    func handleDeviceLinkAuthorized(_ deviceLink: DeviceLink)
 }
diff --git a/SignalServiceKit/src/Loki/API/Multi Device/Notification+DeviceLinking.swift b/SignalServiceKit/src/Loki/API/Multi Device/Notification+DeviceLinking.swift
new file mode 100644
index 000000000..d9a7a4bb3
--- /dev/null
+++ b/SignalServiceKit/src/Loki/API/Multi Device/Notification+DeviceLinking.swift	
@@ -0,0 +1,4 @@
+
+public extension Notification.Name {
+    public static let linkingRequestAuthorized = Notification.Name("linkingRequestAuthorized")
+}
diff --git a/SignalServiceKit/src/Messages/OWSMessageManager.m b/SignalServiceKit/src/Messages/OWSMessageManager.m
index c1f17b9c7..1ec9851cc 100644
--- a/SignalServiceKit/src/Messages/OWSMessageManager.m
+++ b/SignalServiceKit/src/Messages/OWSMessageManager.m
@@ -431,11 +431,12 @@ NS_ASSUME_NONNULL_BEGIN
         // Loki: Handle device linking message
         if (contentProto.lokiDeviceLinkingMessage != nil && contentProto.lokiDeviceLinkingMessage.type == SSKProtoLokiDeviceLinkingMessageTypeRequest) {
             OWSLogInfo(@"[Loki] Received a device linking request from: %@", envelope.source);
-            NSData *signature = contentProto.lokiDeviceLinkingMessage.slaveSignature;
-            if (signature == nil) {
+            NSData *slaveSignature = contentProto.lokiDeviceLinkingMessage.slaveSignature;
+            if (slaveSignature == nil) {
                 OWSFailDebug(@"Received a device linking request without an attached slave signature.");
             }
-            [LKDeviceLinkingSession.current processLinkingRequestFrom:envelope.source with:signature];
+            NSString *masterHexEncodedPublicKey = contentProto.lokiDeviceLinkingMessage.masterHexEncodedPublicKey;
+            [LKDeviceLinkingSession.current processLinkingRequestFrom:envelope.source to:masterHexEncodedPublicKey with:slaveSignature];
         }
         
         // Loki: Handle pre key bundle message