Add encryption key pair request message

Session/Closed Groups/EditClosedGroupVC.swift

@@ -273,7 +273,7 @@ final class EditClosedGroupVC : BaseVC, UITableViewDataSource, UITableViewDelega
                 if !members.contains(getUserHexEncodedPublicKey()) {
                     try MessageSender.leave(groupPublicKey, using: transaction)
                 } else {
-                    try MessageSender.update(groupPublicKey, with: members, name: name, transaction: transaction)
+                    try MessageSender.v2_update(groupPublicKey, with: members, name: name, transaction: transaction)
                 }
             } catch {
                 DispatchQueue.main.async {

SessionMessagingKit/Messages/Control Messages/ClosedGroupControlMessage.swift

@@ -23,11 +23,15 @@ public final class ClosedGroupControlMessage : ControlMessage {
         case new(publicKey: Data, name: String, encryptionKeyPair: ECKeyPair, members: [Data], admins: [Data])
         /// - Note: Deprecated in favor of more explicit group updates.
         case update(name: String, members: [Data])
-        case encryptionKeyPair([KeyPairWrapper]) // The new encryption key pair encrypted for each member individually
+        /// An encryption key pair encrypted for each member individually.
+        ///
+        /// - Note: `publicKey` is only set when an encryption key pair is sent in a one-to-one context (i.e. not in a group).
+        case encryptionKeyPair(publicKey: Data?, wrappers: [KeyPairWrapper])
         case nameChange(name: String)
         case membersAdded(members: [Data])
         case membersRemoved(members: [Data])
         case memberLeft
+        case encryptionKeyPairRequest
 
         public var description: String {
             switch self {
@@ -38,6 +42,7 @@ public final class ClosedGroupControlMessage : ControlMessage {
             case .membersAdded: return "membersAdded"
             case .membersRemoved: return "membersRemoved"
             case .memberLeft: return "memberLeft"
+            case .encryptionKeyPairRequest: return "encryptionKeyPairRequest"
             }
         }
     }
@@ -103,6 +108,7 @@ public final class ClosedGroupControlMessage : ControlMessage {
         case .membersAdded(let members): return !members.isEmpty
         case .membersRemoved(let members): return !members.isEmpty
         case .memberLeft: return true
+        case .encryptionKeyPairRequest: return true
         }
     }
 
@@ -123,8 +129,9 @@ public final class ClosedGroupControlMessage : ControlMessage {
                 let members = coder.decodeObject(forKey: "members") as? [Data] else { return nil }
             self.kind = .update(name: name, members: members)
         case "encryptionKeyPair":
+            let publicKey = coder.decodeObject(forKey: "publicKey") as? Data
             guard let wrappers = coder.decodeObject(forKey: "wrappers") as? [KeyPairWrapper] else { return nil }
-            self.kind = .encryptionKeyPair(wrappers)
+            self.kind = .encryptionKeyPair(publicKey: publicKey, wrappers: wrappers)
         case "nameChange":
             guard let name = coder.decodeObject(forKey: "name") as? String else { return nil }
             self.kind = .nameChange(name: name)
@@ -136,6 +143,8 @@ public final class ClosedGroupControlMessage : ControlMessage {
             self.kind = .membersRemoved(members: members)
         case "memberLeft":
             self.kind = .memberLeft
+        case "encryptionKeyPairRequest":
+            self.kind = .encryptionKeyPairRequest
         default: return nil
         }
     }
@@ -155,8 +164,9 @@ public final class ClosedGroupControlMessage : ControlMessage {
             coder.encode("update", forKey: "kind")
             coder.encode(name, forKey: "name")
             coder.encode(members, forKey: "members")
-        case .encryptionKeyPair(let wrappers):
+        case .encryptionKeyPair(let publicKey, let wrappers):
             coder.encode("encryptionKeyPair", forKey: "kind")
+            coder.encode(publicKey, forKey: "publicKey")
             coder.encode(wrappers, forKey: "wrappers")
         case .nameChange(let name):
             coder.encode("nameChange", forKey: "kind")
@@ -169,6 +179,8 @@ public final class ClosedGroupControlMessage : ControlMessage {
             coder.encode(members, forKey: "members")
         case .memberLeft:
             coder.encode("memberLeft", forKey: "kind")
+        case .encryptionKeyPairRequest:
+            coder.encode("encryptionKeyPairRequest", forKey: "kind")
         }
     }
 
@@ -192,8 +204,9 @@ public final class ClosedGroupControlMessage : ControlMessage {
             guard let name = closedGroupControlMessageProto.name else { return nil }
             kind = .update(name: name, members: closedGroupControlMessageProto.members)
         case .encryptionKeyPair:
+            let publicKey = closedGroupControlMessageProto.publicKey
             let wrappers = closedGroupControlMessageProto.wrappers.compactMap { KeyPairWrapper.fromProto($0) }
-            kind = .encryptionKeyPair(wrappers)
+            kind = .encryptionKeyPair(publicKey: publicKey, wrappers: wrappers)
         case .nameChange:
             guard let name = closedGroupControlMessageProto.name else { return nil }
             kind = .nameChange(name: name)
@@ -203,6 +216,8 @@ public final class ClosedGroupControlMessage : ControlMessage {
             kind = .membersRemoved(members: closedGroupControlMessageProto.members)
         case .memberLeft:
             kind = .memberLeft
+        case .encryptionKeyPairRequest:
+            kind = .encryptionKeyPairRequest
         }
         return ClosedGroupControlMessage(kind: kind)
     }
@@ -232,8 +247,11 @@ public final class ClosedGroupControlMessage : ControlMessage {
                 closedGroupControlMessage = SNProtoDataMessageClosedGroupControlMessage.builder(type: .update)
                 closedGroupControlMessage.setName(name)
                 closedGroupControlMessage.setMembers(members)
-            case .encryptionKeyPair(let wrappers):
+            case .encryptionKeyPair(let publicKey, let wrappers):
                 closedGroupControlMessage = SNProtoDataMessageClosedGroupControlMessage.builder(type: .encryptionKeyPair)
+                if let publicKey = publicKey {
+                    closedGroupControlMessage.setPublicKey(publicKey)
+                }
                 closedGroupControlMessage.setWrappers(wrappers.compactMap { $0.toProto() })
             case .nameChange(let name):
                 closedGroupControlMessage = SNProtoDataMessageClosedGroupControlMessage.builder(type: .nameChange)
@@ -246,6 +264,8 @@ public final class ClosedGroupControlMessage : ControlMessage {
                 closedGroupControlMessage.setMembers(members)
             case .memberLeft:
                 closedGroupControlMessage = SNProtoDataMessageClosedGroupControlMessage.builder(type: .memberLeft)
+            case .encryptionKeyPairRequest:
+                closedGroupControlMessage = SNProtoDataMessageClosedGroupControlMessage.builder(type: .encryptionKeyPairRequest)
             }
             let contentProto = SNProtoContent.builder()
             let dataMessageProto = SNProtoDataMessage.builder()

SessionMessagingKit/Protos/Generated/SNProto.swift

@@ -2410,6 +2410,7 @@ extension SNProtoDataMessageClosedGroupControlMessageKeyPairWrapper.SNProtoDataM
         case membersAdded = 5
         case membersRemoved = 6
         case memberLeft = 7
+        case encryptionKeyPairRequest = 8
     }
 
     private class func SNProtoDataMessageClosedGroupControlMessageTypeWrap(_ value: SessionProtos_DataMessage.ClosedGroupControlMessage.TypeEnum) -> SNProtoDataMessageClosedGroupControlMessageType {
@@ -2421,6 +2422,7 @@ extension SNProtoDataMessageClosedGroupControlMessageKeyPairWrapper.SNProtoDataM
         case .membersAdded: return .membersAdded
         case .membersRemoved: return .membersRemoved
         case .memberLeft: return .memberLeft
+        case .encryptionKeyPairRequest: return .encryptionKeyPairRequest
         }
     }
 
@@ -2433,6 +2435,7 @@ extension SNProtoDataMessageClosedGroupControlMessageKeyPairWrapper.SNProtoDataM
         case .membersAdded: return .membersAdded
         case .membersRemoved: return .membersRemoved
         case .memberLeft: return .memberLeft
+        case .encryptionKeyPairRequest: return .encryptionKeyPairRequest
         }
     }
 

SessionMessagingKit/Protos/Generated/SessionProtos.pb.swift

@@ -1152,6 +1152,9 @@ struct SessionProtos_DataMessage {
       case membersRemoved // = 6
       case memberLeft // = 7
 
+      /// wrappers
+      case encryptionKeyPairRequest // = 8
+
       init() {
         self = .new
       }
@@ -1165,6 +1168,7 @@ struct SessionProtos_DataMessage {
         case 5: self = .membersAdded
         case 6: self = .membersRemoved
         case 7: self = .memberLeft
+        case 8: self = .encryptionKeyPairRequest
         default: return nil
         }
       }
@@ -1178,6 +1182,7 @@ struct SessionProtos_DataMessage {
         case .membersAdded: return 5
         case .membersRemoved: return 6
         case .memberLeft: return 7
+        case .encryptionKeyPairRequest: return 8
         }
       }
 
@@ -3131,6 +3136,7 @@ extension SessionProtos_DataMessage.ClosedGroupControlMessage.TypeEnum: SwiftPro
     5: .same(proto: "MEMBERS_ADDED"),
     6: .same(proto: "MEMBERS_REMOVED"),
     7: .same(proto: "MEMBER_LEFT"),
+    8: .same(proto: "ENCRYPTION_KEY_PAIR_REQUEST"),
   ]
 }
 

SessionMessagingKit/Protos/SessionProtos.proto

@@ -169,13 +169,14 @@ message DataMessage {
   message ClosedGroupControlMessage {
 
     enum Type {
-      NEW                 = 1; // publicKey, name, encryptionKeyPair, members, admins
-      UPDATE              = 2; // name, members
-      ENCRYPTION_KEY_PAIR = 3; // wrappers
-      NAME_CHANGE         = 4; // name
-      MEMBERS_ADDED       = 5; // members
-      MEMBERS_REMOVED     = 6; // members
-      MEMBER_LEFT         = 7;
+      NEW                         = 1; // publicKey, name, encryptionKeyPair, members, admins
+      UPDATE                      = 2; // name, members
+      ENCRYPTION_KEY_PAIR         = 3; // publicKey, wrappers
+      NAME_CHANGE                 = 4; // name
+      MEMBERS_ADDED               = 5; // members
+      MEMBERS_REMOVED             = 6; // members
+      MEMBER_LEFT                 = 7;
+      ENCRYPTION_KEY_PAIR_REQUEST = 8;
     }
 
     message KeyPairWrapper {

SessionMessagingKit/Sending & Receiving/MessageReceiver+Handling.swift

@@ -253,6 +253,7 @@ extension MessageReceiver {
         case .membersAdded: handleClosedGroupMembersAdded(message, using: transaction)
         case .membersRemoved: handleClosedGroupMembersRemoved(message, using: transaction)
         case .memberLeft: handleClosedGroupMemberLeft(message, using: transaction)
+        case .encryptionKeyPairRequest: handleClosedGroupEncryptionKeyPairRequest(message, using: transaction)
         }
     }
     
@@ -294,7 +295,8 @@ extension MessageReceiver {
 
     private static func handleClosedGroupEncryptionKeyPair(_ message: ClosedGroupControlMessage, using transaction: Any) {
         // Prepare
-        guard case let .encryptionKeyPair(wrappers) = message.kind, let groupPublicKey = message.groupPublicKey else { return }
+        guard case let .encryptionKeyPair(explicitGroupPublicKey, wrappers) = message.kind,
+            let groupPublicKey = explicitGroupPublicKey?.toHexString() ?? message.groupPublicKey else { return }
         let transaction = transaction as! YapDatabaseReadWriteTransaction
         let userPublicKey = getUserHexEncodedPublicKey()
         guard let userKeyPair = SNMessagingKitConfiguration.shared.storage.getUserKeyPair() else {
@@ -305,8 +307,8 @@ extension MessageReceiver {
         guard let thread = TSGroupThread.fetch(uniqueId: threadID, transaction: transaction) else {
             return SNLog("Ignoring closed group encryption key pair for nonexistent group.")
         }
-        guard thread.groupModel.groupAdminIds.contains(message.sender!) else {
-            return SNLog("Ignoring closed group encryption key pair from non-admin.")
+        guard thread.groupModel.groupMemberIds.contains(message.sender!) else {
+            return SNLog("Ignoring closed group encryption key pair from non-member.")
         }
         // Find our wrapper and decrypt it if possible
         guard let wrapper = wrappers.first(where: { $0.publicKey == userPublicKey }), let encryptedKeyPair = wrapper.encryptedKeyPair else { return }
@@ -329,7 +331,11 @@ extension MessageReceiver {
         } catch {
             return SNLog("Couldn't parse closed group encryption key pair.")
         }
-        // Store it
+        // Store it if needed
+        let closedGroupEncryptionKeyPairs = Storage.shared.getClosedGroupEncryptionKeyPairs(for: groupPublicKey)
+        guard !closedGroupEncryptionKeyPairs.contains(keyPair) else {
+            return SNLog("Ignoring duplicate closed group encryption key pair.")
+        }
         Storage.shared.addClosedGroupEncryptionKeyPair(keyPair, for: groupPublicKey, using: transaction)
         SNLog("Received a new closed group encryption key pair.")
     }
@@ -450,6 +456,30 @@ extension MessageReceiver {
         }
     }
     
+    private static func handleClosedGroupEncryptionKeyPairRequest(_ message: ClosedGroupControlMessage, using transaction: Any) {
+        guard case .encryptionKeyPairRequest = message.kind else { return }
+        let transaction = transaction as! YapDatabaseReadWriteTransaction
+        guard let groupPublicKey = message.groupPublicKey else { return }
+        performIfValid(for: message, using: transaction) { groupID, _, group in
+            let publicKey = message.sender!
+            // Guard against self-sends
+            guard publicKey != getUserHexEncodedPublicKey() else {
+                return SNLog("Ignoring invalid closed group update.")
+            }
+            // Get the latest encryption key pair
+            guard let encryptionKeyPair = Storage.shared.getLatestClosedGroupEncryptionKeyPair(for: groupPublicKey) else { return }
+            // Send it
+            guard let proto = try? SNProtoKeyPair.builder(publicKey: encryptionKeyPair.publicKey,
+                privateKey: encryptionKeyPair.privateKey).build(), let plaintext = try? proto.serializedData() else { return }
+            let thread = TSContactThread.getOrCreateThread(withContactId: publicKey, transaction: transaction)
+            guard let ciphertext = try? MessageSender.encryptWithSessionProtocol(plaintext, for: publicKey) else { return }
+            SNLog("Responding to closed group encryption key pair request from: \(publicKey).")
+            let wrapper = ClosedGroupControlMessage.KeyPairWrapper(publicKey: publicKey, encryptedKeyPair: ciphertext)
+            let closedGroupControlMessage = ClosedGroupControlMessage(kind: .encryptionKeyPair(publicKey: Data(hex: groupPublicKey), wrappers: [ wrapper ]))
+            MessageSender.send(closedGroupControlMessage, in: thread, using: transaction)
+        }
+    }
+    
     private static func performIfValid(for message: ClosedGroupControlMessage, using transaction: Any, _ update: (Data, TSGroupThread, TSGroupModel) -> Void) {
         // Prepare
         let transaction = transaction as! YapDatabaseReadWriteTransaction

SessionMessagingKit/Sending & Receiving/MessageReceiver.swift

@@ -22,7 +22,7 @@ public enum MessageReceiver {
 
         public var isRetryable: Bool {
             switch self {
-            case .duplicateMessage, .invalidMessage, .unknownMessage, .unknownEnvelopeType, .invalidSignature, .noData, .senderBlocked, .selfSend, .decryptionFailed: return false
+            case .duplicateMessage, .invalidMessage, .unknownMessage, .unknownEnvelopeType, .invalidSignature, .noData, .senderBlocked, .selfSend: return false
             default: return true
             }
         }
@@ -88,8 +88,17 @@ public enum MessageReceiver {
                         }
                     }
                 }
-                try decrypt()
                 groupPublicKey = envelope.source
+                do {
+                    try decrypt()
+                } catch {
+                    do {
+                        try MessageSender.requestEncryptionKeyPair(for: groupPublicKey!, using: transaction as! YapDatabaseReadWriteTransaction)
+                    } catch {
+                        // Do nothing
+                    }
+                    throw error // Throw the * decryption * error and not the error generated by requestEncryptionKeyPair (if it generated one)
+                }
             default: throw Error.unknownEnvelopeType
             }
         }

SessionMessagingKit/Sending & Receiving/MessageSender+ClosedGroups.swift

@@ -69,7 +69,7 @@ extension MessageSender {
             let ciphertext = try MessageSender.encryptWithSessionProtocol(plaintext, for: publicKey)
             return ClosedGroupControlMessage.KeyPairWrapper(publicKey: publicKey, encryptedKeyPair: ciphertext)
         }
-        let closedGroupControlMessage = ClosedGroupControlMessage(kind: .encryptionKeyPair(wrappers))
+        let closedGroupControlMessage = ClosedGroupControlMessage(kind: .encryptionKeyPair(publicKey: nil, wrappers: wrappers))
         let _ = MessageSender.sendNonDurably(closedGroupControlMessage, in: thread, using: transaction).done { // FIXME: It'd be great if we could make this a durable operation
             // Store it * after * having sent out the message to the group
             SNMessagingKitConfiguration.shared.storage.write { transaction in
@@ -234,6 +234,21 @@ extension MessageSender {
         infoMessage.save(with: transaction)
     }
     
+    public static func requestEncryptionKeyPair(for groupPublicKey: String, using transaction: YapDatabaseReadWriteTransaction) throws {
+        // Get the group, check preconditions & prepare
+        let groupID = LKGroupUtilities.getEncodedClosedGroupIDAsData(groupPublicKey)
+        let threadID = TSGroupThread.threadId(fromGroupId: groupID)
+        guard let thread = TSGroupThread.fetch(uniqueId: threadID, transaction: transaction) else {
+            SNLog("Can't request encryption key pair for nonexistent closed group.")
+            throw Error.noThread
+        }
+        let group = thread.groupModel
+        guard group.groupMemberIds.contains(getUserHexEncodedPublicKey()) else { return }
+        // Send the request to the group
+        let closedGroupControlMessage = ClosedGroupControlMessage(kind: .encryptionKeyPairRequest)
+        MessageSender.send(closedGroupControlMessage, in: thread, using: transaction)
+    }
+    
     
     
     // MARK: - Deprecated