element-hq/element-ios/issues/4406 - Implemented Olm fallback key sup…

…port.

MatrixSDK/Contrib/Swift/MXRestClient.swift

@@ -1727,13 +1727,14 @@ public extension MXRestClient {
      - parameters:
         - deviceKeys: the device keys to send.
         - oneTimeKeys: the one-time keys to send.
+        - fallbackKeys: the fallback keys to send
         - completion: A block object called when the operation completes.
         - response: Provides information about the keys on success.
 
      - returns: a `MXHTTPOperation` instance.
      */
-    @nonobjc @discardableResult func uploadKeys(_ deviceKeys: [String: Any], oneTimeKeys: [String: Any], forDevice deviceId: String? = nil, completion: @escaping (_ response: MXResponse<MXKeysUploadResponse>) -> Void) -> MXHTTPOperation {
-        return __uploadKeys(deviceKeys, oneTimeKeys: oneTimeKeys, success: currySuccess(completion), failure: curryFailure(completion))
+    @nonobjc @discardableResult func uploadKeys(_ deviceKeys: [String: Any]?, oneTimeKeys: [String: Any]?, fallbackKeys: [String: Any]?, forDevice deviceId: String? = nil, completion: @escaping (_ response: MXResponse<MXKeysUploadResponse>) -> Void) -> MXHTTPOperation {
+        return __uploadKeys(deviceKeys, oneTimeKeys: oneTimeKeys, fallbackKeys: fallbackKeys, success: currySuccess(completion), failure: curryFailure(completion))
     }
 
     /**

MatrixSDK/Crypto/MXCrypto.h

@@ -255,6 +255,13 @@ extern NSString *const MXDeviceListDidUpdateUsersDevicesNotification;
  */
 - (void)handleDeviceOneTimeKeysCount:(NSDictionary<NSString *, NSNumber*>*)deviceOneTimeKeysCount;
 
+/**
+ Handle the unused fallback keys returned in the /sync response.
+
+ @param deviceUnusedFallbackKeys the algorithms for which there are unused fallback keys
+ */
+- (void)handleDeviceUnusedFallbackKeys:(NSArray<NSString *> *)deviceUnusedFallbackKeys;
+
 /**
  Handle a room key event.
  

MatrixSDK/Crypto/MXOlmDevice.h

@@ -98,6 +98,20 @@
  */
 - (void)generateOneTimeKeys:(NSUInteger)numKeys;
 
+/**
+ The current fallback key for this account.
+
+ @return a dictionary with one key which is "curve25519".
+         Its value is a dictionary where keys are keys ids
+         and values, the Curve25519 keys.
+ */
+@property (nonatomic, readonly) NSDictionary *fallbackKey;
+
+/**
+ Generate a new fallback key
+ */
+- (void)generateFallbackKey;
+
 /**
  Generate a new outbound session.
  

MatrixSDK/Crypto/MXOlmDevice.m

@@ -141,6 +141,18 @@ - (void)generateOneTimeKeys:(NSUInteger)numKeys
     }];
 }
 
+- (NSDictionary *)fallbackKey
+{
+    return store.account.fallbackKey;
+}
+
+- (void)generateFallbackKey
+{
+    [store performAccountOperationWithBlock:^(OLMAccount *olmAccount) {
+        [olmAccount generateFallbackKey];
+    }];
+}
+
 - (NSString *)createOutboundSession:(NSString *)theirIdentityKey theirOneTimeKey:(NSString *)theirOneTimeKey
 {
     NSError *error;

MatrixSDK/JSONModels/Sync/MXSyncResponse.h

@@ -60,6 +60,11 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @property (nonatomic, nullable) NSDictionary<NSString *, NSNumber*> *deviceOneTimeKeysCount;
 
+/**
+ List of algorithms for which the server has unused fallback keys
+ */
+@property (nonatomic, nullable) NSArray<NSString*> *unusedFallbackKeys;
+
 /**
  List of rooms.
  */

MatrixSDK/JSONModels/Sync/MXSyncResponse.m

@@ -22,6 +22,8 @@
 #import "MXRoomsSyncResponse.h"
 #import "MXGroupsSyncResponse.h"
 
+static NSString * const kMXDeviceUnusedFallbackKeyTypesKey = @"org.matrix.msc2732.device_unused_fallback_key_types";
+
 @implementation MXSyncResponse
 
 + (id)modelFromJSON:(NSDictionary *)JSONDictionary
@@ -35,6 +37,7 @@ + (id)modelFromJSON:(NSDictionary *)JSONDictionary
         MXJSONModelSetMXJSONModel(syncResponse.toDevice, MXToDeviceSyncResponse, JSONDictionary[@"to_device"]);
         MXJSONModelSetMXJSONModel(syncResponse.deviceLists, MXDeviceListResponse, JSONDictionary[@"device_lists"]);
         MXJSONModelSetDictionary(syncResponse.deviceOneTimeKeysCount, JSONDictionary[@"device_one_time_keys_count"])
+        MXJSONModelSetArray(syncResponse.unusedFallbackKeys, JSONDictionary[kMXDeviceUnusedFallbackKeyTypesKey])
         MXJSONModelSetMXJSONModel(syncResponse.rooms, MXRoomsSyncResponse, JSONDictionary[@"rooms"]);
         MXJSONModelSetMXJSONModel(syncResponse.groups, MXGroupsSyncResponse, JSONDictionary[@"groups"]);
     }
@@ -67,6 +70,10 @@ - (NSDictionary *)JSONDictionary
     {
         JSONDictionary[@"device_one_time_keys_count"] = self.deviceOneTimeKeysCount;
     }
+    if (self.unusedFallbackKeys)
+    {
+        JSONDictionary[kMXDeviceUnusedFallbackKeyTypesKey] = self.unusedFallbackKeys;
+    }
     if (self.rooms)
     {
         JSONDictionary[@"rooms"] = self.rooms.JSONDictionary;

MatrixSDK/MXRestClient.h

@@ -2137,13 +2137,16 @@ Get the maximum size a media upload can be in bytes.
 
  @param deviceKeys the device keys to send.
  @param oneTimeKeys the one-time keys to send.
+ @param fallbackKeys the fallback keys to send.
 
  @param success A block object called when the operation succeeds.
  @param failure A block object called when the operation fails.
 
  @return a MXHTTPOperation instance.
  */
-- (MXHTTPOperation*)uploadKeys:(NSDictionary*)deviceKeys oneTimeKeys:(NSDictionary*)oneTimeKeys
+- (MXHTTPOperation*)uploadKeys:(NSDictionary*)deviceKeys
+                   oneTimeKeys:(NSDictionary*)oneTimeKeys
+                  fallbackKeys:(NSDictionary *)fallbackKeys
                        success:(void (^)(MXKeysUploadResponse *keysUploadResponse))success
                        failure:(void (^)(NSError *error))failure NS_REFINED_FOR_SWIFT;
 

MatrixSDK/MXRestClient.m

@@ -4046,14 +4046,18 @@ - (MXHTTPOperation*)searchUsers:(NSString*)pattern
 
 
 #pragma mark - Crypto
-- (MXHTTPOperation*)uploadKeys:(NSDictionary*)deviceKeys oneTimeKeys:(NSDictionary*)oneTimeKeys
+- (MXHTTPOperation*)uploadKeys:(NSDictionary*)deviceKeys
+                   oneTimeKeys:(NSDictionary*)oneTimeKeys
+                  fallbackKeys:(NSDictionary *)fallbackKeys
                        success:(void (^)(MXKeysUploadResponse *keysUploadResponse))success
                        failure:(void (^)(NSError *error))failure
 {
-    return [self uploadKeys:deviceKeys oneTimeKeys:oneTimeKeys forDeviceWithId:nil success:success failure:failure];
+    return [self uploadKeys:deviceKeys oneTimeKeys:oneTimeKeys fallbackKeys:fallbackKeys forDeviceWithId:nil success:success failure:failure];
 }
 
-- (MXHTTPOperation*)uploadKeys:(NSDictionary*)deviceKeys oneTimeKeys:(NSDictionary*)oneTimeKeys
+- (MXHTTPOperation*)uploadKeys:(NSDictionary*)deviceKeys
+                   oneTimeKeys:(NSDictionary*)oneTimeKeys
+                  fallbackKeys:(NSDictionary *)fallbackKeys
                forDeviceWithId:(NSString*)deviceId
                        success:(void (^)(MXKeysUploadResponse *keysUploadResponse))success
                        failure:(void (^)(NSError *error))failure
@@ -4069,6 +4073,10 @@ - (MXHTTPOperation*)uploadKeys:(NSDictionary*)deviceKeys oneTimeKeys:(NSDictiona
     {
         parameters[@"one_time_keys"] = oneTimeKeys;
     }
+    if (fallbackKeys)
+    {
+        parameters[@"org.matrix.msc2732.fallback_keys"] = fallbackKeys;
+    }
 
     MXWeakify(self);
     return [httpClient requestWithMethod:@"POST"

MatrixSDK/MXSession.m

@@ -649,6 +649,8 @@ - (void)handleSyncResponse:(MXSyncResponse *)syncResponse
                     [self.crypto handleDeviceOneTimeKeysCount:syncResponse.deviceOneTimeKeysCount];
                 }
 
+                [self.crypto handleDeviceUnusedFallbackKeys:syncResponse.unusedFallbackKeys];
+
                 // Tell the crypto module to do its processing
                 [self.crypto onSyncCompleted:self.store.eventStreamToken
                                nextSyncToken:syncResponse.nextBatch