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
  31 #if OCTAGON
  32
  33 @interface CKKSSynchronizeOperation ()
  34 @property int32_t restartCount;
  35 @end
  36
  37 @implementation CKKSSynchronizeOperation
  38
  39 - (instancetype)init {
  40     return nil;
  41 }
  42 - (instancetype)initWithCKKSKeychainView:(CKKSKeychainView*)ckks {
  43     if(self = [super init]) {
  44         _ckks = ckks;
  45         _restartCount = 0;
  46     }
  47     return self;
  48 }
  49
  50 - (void)groupStart {
  51     __weak __typeof(self) weakSelf = self;
  52
  53     /*
  54      * Synchronizations (or resynchronizations) are complicated beasts. We will:
  55      *
  56      *  1. Finish processing the outgoing queue. You can't be in-sync with cloudkit if you have an update that hasn't propagated.
  57      *  2. Kick off a normal CloudKit fetch.
  58      *  3. Process the incoming queue as normal.
  59      *          (Note that this requires the keybag to be unlocked.)
  60      *
  61      * So far, this is normal operation. Now:
  62      *
  63      *  4. Start another CloudKit fetch, giving it the nil change tag. This fetches all objects in CloudKit.
  64      *    4a. Compare those objects against our local mirror. If any discrepancies, this is a bug.
  65      *    4b. All conflicts: CloudKit data wins.
  66      *    4c. All items we have that CloudKit doesn't: delete locally.
  67      *
  68      *  5. Process the incoming queue again. This should be empty.
  69      *  6. Scan the local keychain for items which exist locally but are not in CloudKit. Upload them.
  70      *  7. If there are any such items in 6, restart the sync.
  71      */
  72
  73     // Promote to strong reference
  74     CKKSKeychainView* ckks = self.ckks;
  75
  76     // Synchronous, on some thread. Get back on the CKKS queue for SQL thread-safety.
  77     [ckks dispatchSync: ^bool{
  78         if(self.cancelled) {
  79             ckksnotice("ckksresync", ckks, "CKKSSynchronizeOperation cancelled, quitting");
  80             return false;
  81         }
  82
  83         ckks.lastSynchronizeOperation = self;
  84
  85         uint32_t steps = 7;
  86
  87         ckksinfo("ckksresync", ckks, "Beginning resynchronize (attempt %u)", self.restartCount);
  88
  89         CKOperationGroup* operationGroup = [CKOperationGroup CKKSGroupWithName:@"ckks-resync"];
  90
  91         // Step 1
  92         CKKSOutgoingQueueOperation* outgoingOp = [ckks processOutgoingQueue: operationGroup];
  93         outgoingOp.name = [NSString stringWithFormat: @"resync-step%u-outgoing", self.restartCount * steps + 1];
  94         [self dependOnBeforeGroupFinished:outgoingOp];
  95
  96         // Step 2
  97         CKKSFetchAllRecordZoneChangesOperation* fetchOp = [[CKKSFetchAllRecordZoneChangesOperation alloc] initWithCKKSKeychainView:ckks
  98                                                                                                                       fetchReasons:[NSSet setWithObject:CKKSFetchBecauseResync]
  99                                                                                                                   ckoperationGroup:operationGroup];
 100         fetchOp.name = [NSString stringWithFormat: @"resync-step%u-fetch", self.restartCount * steps + 2];
 101         [fetchOp addSuccessDependency: outgoingOp];
 102         [self runBeforeGroupFinished: fetchOp];
 103
 104         // Step 3
 105         CKKSIncomingQueueOperation* incomingOp = [[CKKSIncomingQueueOperation alloc] initWithCKKSKeychainView:ckks errorOnClassAFailure:true];
 106         incomingOp.name = [NSString stringWithFormat: @"resync-step%u-incoming", self.restartCount * steps + 3];
 107         [incomingOp addSuccessDependency:fetchOp];
 108         [self runBeforeGroupFinished:incomingOp];
 109
 110         // Now, get serious:
 111
 112         // Step 4
 113         CKKSFetchAllRecordZoneChangesOperation* fetchAllOp = [[CKKSFetchAllRecordZoneChangesOperation alloc] initWithCKKSKeychainView:ckks
 114                                                                                                                          fetchReasons:[NSSet setWithObject:CKKSFetchBecauseResync]
 115                                                                                                                      ckoperationGroup:operationGroup];
 116         fetchAllOp.resync = true;
 117         fetchAllOp.name = [NSString stringWithFormat: @"resync-step%u-fetchAll", self.restartCount * steps + 4];
 118         [fetchAllOp addSuccessDependency: incomingOp];
 119         [self runBeforeGroupFinished: fetchAllOp];
 120
 121         // Step 5
 122         CKKSIncomingQueueOperation* incomingResyncOp = [[CKKSIncomingQueueOperation alloc] initWithCKKSKeychainView:ckks errorOnClassAFailure:true];
 123         incomingResyncOp.name = [NSString stringWithFormat: @"resync-step%u-incoming", self.restartCount * steps + 5];
 124         [incomingResyncOp addSuccessDependency: fetchAllOp];
 125         [self runBeforeGroupFinished:incomingResyncOp];
 126
 127         // Step 6
 128         CKKSScanLocalItemsOperation* scan = [[CKKSScanLocalItemsOperation alloc] initWithCKKSKeychainView:ckks ckoperationGroup:operationGroup];
 129         scan.name = [NSString stringWithFormat: @"resync-step%u-scan", self.restartCount * steps + 6];
 130         [scan addSuccessDependency: incomingResyncOp];
 131         [self runBeforeGroupFinished: scan];
 132
 133         // Step 7:
 134         CKKSResultOperation* restart = [[CKKSResultOperation alloc] init];
 135         restart.name = [NSString stringWithFormat: @"resync-step%u-consider-restart", self.restartCount * steps + 7];
 136         [restart addExecutionBlock:^{
 137             __strong __typeof(weakSelf) strongSelf = weakSelf;
 138             if(!strongSelf) {
 139                 secerror("ckksresync: received callback for released object");
 140                 return;
 141             }
 142
 143             if(scan.recordsFound > 0) {
 144                 if(strongSelf.restartCount >= 3) {
 145                     // we've restarted too many times. Fail and stop.
 146                     ckkserror("ckksresync", ckks, "restarted synchronization too often; Failing");
 147                     strongSelf.error = [NSError errorWithDomain:@"securityd"
 148                                                          code:2
 149                                                      userInfo:@{NSLocalizedDescriptionKey: @"resynchronization restarted too many times; churn in database?"}];
 150                 } else {
 151                     // restart the sync operation.
 152                     strongSelf.restartCount += 1;
 153                     ckkserror("ckksresync", ckks, "restarting synchronization operation due to new local items");
 154                     [strongSelf groupStart];
 155                 }
 156             }
 157         }];
 158
 159         [restart addSuccessDependency: scan];
 160         [self runBeforeGroupFinished: restart];
 161
 162         return true;
 163     }];
 164 }
 165
 166 @end;
 167
 168 #endif