keychain/ckks/CKKSSynchronizeOperation.m

   1 /*
   2  * Copyright (c) 2016 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #import "CKKSKeychainView.h"
  25 #import "CKKSGroupOperation.h"
  26 #import "CKKSSynchronizeOperation.h"
  27 #import "CKKSFetchAllRecordZoneChangesOperation.h"
  28 #import "CKKSScanLocalItemsOperation.h"
  29 #import "keychain/ckks/CloudKitCategories.h"
  30 #import "keychain/categories/NSError+UsefulConstructors.h"
  31
  32 #if OCTAGON
  33
  34 @interface CKKSSynchronizeOperation ()
  35 @property int32_t restartCount;
  36 @end
  37
  38 @implementation CKKSSynchronizeOperation
  39
  40 - (instancetype)init {
  41     return nil;
  42 }
  43 - (instancetype)initWithCKKSKeychainView:(CKKSKeychainView*)ckks {
  44     if(self = [super init]) {
  45         _ckks = ckks;
  46         _restartCount = 0;
  47     }
  48     return self;
  49 }
  50
  51 - (void)groupStart {
  52     __weak __typeof(self) weakSelf = self;
  53
  54     /*
  55      * Synchronizations (or resynchronizations) are complicated beasts. We will:
  56      *
  57      *  1. Finish processing the outgoing queue. You can't be in-sync with cloudkit if you have an update that hasn't propagated.
  58      *  2. Kick off a normal CloudKit fetch.
  59      *  3. Process the incoming queue as normal.
  60      *          (Note that this requires the keybag to be unlocked.)
  61      *
  62      * So far, this is normal operation. Now:
  63      *
  64      *  4. Start another CloudKit fetch, giving it the nil change tag. This fetches all objects in CloudKit.
  65      *    4a. Compare those objects against our local mirror. If any discrepancies, this is a bug.
  66      *    4b. All conflicts: CloudKit data wins.
  67      *    4c. All items we have that CloudKit doesn't: delete locally.
  68      *
  69      *  5. Process the incoming queue again. This should be empty.
  70      *  6. Scan the local keychain for items which exist locally but are not in CloudKit. Upload them.
  71      *  7. If there are any such items in 6, restart the sync.
  72      */
  73
  74     // Promote to strong reference
  75     CKKSKeychainView* ckks = self.ckks;
  76
  77     // Synchronous, on some thread. Get back on the CKKS queue for SQL thread-safety.
  78     [ckks dispatchSync: ^bool{
  79         if(self.cancelled) {
  80             ckksnotice("ckksresync", ckks, "CKKSSynchronizeOperation cancelled, quitting");
  81             return false;
  82         }
  83
  84         ckks.lastSynchronizeOperation = self;
  85
  86         uint32_t steps = 7;
  87
  88         ckksinfo("ckksresync", ckks, "Beginning resynchronize (attempt %u)", self.restartCount);
  89
  90         CKOperationGroup* operationGroup = [CKOperationGroup CKKSGroupWithName:@"ckks-resync"];
  91
  92         // Step 1
  93         CKKSOutgoingQueueOperation* outgoingOp = [ckks processOutgoingQueue: operationGroup];
  94         outgoingOp.name = [NSString stringWithFormat: @"resync-step%u-outgoing", self.restartCount * steps + 1];
  95         [self dependOnBeforeGroupFinished:outgoingOp];
  96
  97         // Step 2
  98         CKKSFetchAllRecordZoneChangesOperation* fetchOp = [[CKKSFetchAllRecordZoneChangesOperation alloc] initWithContainer:ckks.container
  99                                                                                                                  fetchClass:ckks.fetchRecordZoneChangesOperationClass
 100                                                                                                                      clients:@[ckks]
 101                                                                                                                fetchReasons:[NSSet setWithObject:CKKSFetchBecauseResync]
 102                                                                                                                  apnsPushes:nil
 103                                                                                                                 forceResync:true
 104                                                                                                            ckoperationGroup:operationGroup];
 105         fetchOp.name = [NSString stringWithFormat: @"resync-step%u-fetch", self.restartCount * steps + 2];
 106         [fetchOp addSuccessDependency: outgoingOp];
 107         [self runBeforeGroupFinished: fetchOp];
 108
 109         // Step 3
 110         CKKSIncomingQueueOperation* incomingOp = [[CKKSIncomingQueueOperation alloc] initWithCKKSKeychainView:ckks errorOnClassAFailure:true];
 111         incomingOp.name = [NSString stringWithFormat: @"resync-step%u-incoming", self.restartCount * steps + 3];
 112         [incomingOp addSuccessDependency:fetchOp];
 113         [self runBeforeGroupFinished:incomingOp];
 114
 115         // Now, get serious:
 116
 117         // Step 4
 118         CKKSFetchAllRecordZoneChangesOperation* fetchAllOp = [[CKKSFetchAllRecordZoneChangesOperation alloc] initWithContainer:ckks.container
 119                                                                                                                     fetchClass:ckks.fetchRecordZoneChangesOperationClass
 120                                                                                                                         clients:@[ckks]
 121                                                                                                                    fetchReasons:[NSSet setWithObject:CKKSFetchBecauseResync]
 122                                                                                                                     apnsPushes:nil
 123                                                                                                                    forceResync:true
 124                                                                                                                ckoperationGroup:operationGroup];
 125         fetchAllOp.resync = true;
 126         fetchAllOp.name = [NSString stringWithFormat: @"resync-step%u-fetchAll", self.restartCount * steps + 4];
 127         [fetchAllOp addSuccessDependency: incomingOp];
 128         [self runBeforeGroupFinished: fetchAllOp];
 129
 130         // Step 5
 131         CKKSIncomingQueueOperation* incomingResyncOp = [[CKKSIncomingQueueOperation alloc] initWithCKKSKeychainView:ckks errorOnClassAFailure:true];
 132         incomingResyncOp.name = [NSString stringWithFormat: @"resync-step%u-incoming", self.restartCount * steps + 5];
 133         [incomingResyncOp addSuccessDependency: fetchAllOp];
 134         [self runBeforeGroupFinished:incomingResyncOp];
 135
 136         // Step 6
 137         CKKSScanLocalItemsOperation* scan = [[CKKSScanLocalItemsOperation alloc] initWithCKKSKeychainView:ckks ckoperationGroup:operationGroup];
 138         scan.name = [NSString stringWithFormat: @"resync-step%u-scan", self.restartCount * steps + 6];
 139         [scan addSuccessDependency: incomingResyncOp];
 140         [self runBeforeGroupFinished: scan];
 141
 142         // Step 7:
 143         CKKSResultOperation* restart = [[CKKSResultOperation alloc] init];
 144         restart.name = [NSString stringWithFormat: @"resync-step%u-consider-restart", self.restartCount * steps + 7];
 145         [restart addExecutionBlock:^{
 146             __strong __typeof(weakSelf) strongSelf = weakSelf;
 147             if(!strongSelf) {
 148                 secerror("ckksresync: received callback for released object");
 149                 return;
 150             }
 151
 152             if(scan.recordsFound > 0) {
 153                 if(strongSelf.restartCount >= 3) {
 154                     // we've restarted too many times. Fail and stop.
 155                     ckkserror("ckksresync", ckks, "restarted synchronization too often; Failing");
 156                     strongSelf.error = [NSError errorWithDomain:@"securityd"
 157                                                          code:2
 158                                                      userInfo:@{NSLocalizedDescriptionKey: @"resynchronization restarted too many times; churn in database?"}];
 159                 } else {
 160                     // restart the sync operation.
 161                     strongSelf.restartCount += 1;
 162                     ckkserror("ckksresync", ckks, "restarting synchronization operation due to new local items");
 163                     [strongSelf groupStart];
 164                 }
 165             }
 166         }];
 167
 168         [restart addSuccessDependency: scan];
 169         [self runBeforeGroupFinished: restart];
 170
 171         return true;
 172     }];
 173 }
 174
 175 @end;
 176
 177 #endif