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 ckoperationGroup:operationGroup];
  98         fetchOp.name = [NSString stringWithFormat: @"resync-step%u-fetch", self.restartCount * steps + 2];
  99         [fetchOp addSuccessDependency: outgoingOp];
 100         [self runBeforeGroupFinished: fetchOp];
 101
 102         // Step 3
 103         CKKSIncomingQueueOperation* incomingOp = [[CKKSIncomingQueueOperation alloc] initWithCKKSKeychainView:ckks errorOnClassAFailure:true];
 104         incomingOp.name = [NSString stringWithFormat: @"resync-step%u-incoming", self.restartCount * steps + 3];
 105         [incomingOp addSuccessDependency:fetchOp];
 106         [self runBeforeGroupFinished:incomingOp];
 107
 108         // Now, get serious:
 109
 110         // Step 4
 111         CKKSFetchAllRecordZoneChangesOperation* fetchAllOp = [[CKKSFetchAllRecordZoneChangesOperation alloc] initWithCKKSKeychainView:ckks ckoperationGroup:operationGroup];
 112         fetchAllOp.resync = true;
 113         fetchAllOp.name = [NSString stringWithFormat: @"resync-step%u-fetchAll", self.restartCount * steps + 4];
 114         [fetchAllOp addSuccessDependency: incomingOp];
 115         [self runBeforeGroupFinished: fetchAllOp];
 116
 117         // Step 5
 118         CKKSIncomingQueueOperation* incomingResyncOp = [[CKKSIncomingQueueOperation alloc] initWithCKKSKeychainView:ckks errorOnClassAFailure:true];
 119         incomingResyncOp.name = [NSString stringWithFormat: @"resync-step%u-incoming", self.restartCount * steps + 5];
 120         [incomingResyncOp addSuccessDependency: fetchAllOp];
 121         [self runBeforeGroupFinished:incomingResyncOp];
 122
 123         // Step 6
 124         CKKSScanLocalItemsOperation* scan = [[CKKSScanLocalItemsOperation alloc] initWithCKKSKeychainView:ckks ckoperationGroup:operationGroup];
 125         scan.name = [NSString stringWithFormat: @"resync-step%u-scan", self.restartCount * steps + 6];
 126         [scan addSuccessDependency: incomingResyncOp];
 127         [self runBeforeGroupFinished: scan];
 128
 129         // Step 7:
 130         CKKSResultOperation* restart = [[CKKSResultOperation alloc] init];
 131         restart.name = [NSString stringWithFormat: @"resync-step%u-consider-restart", self.restartCount * steps + 7];
 132         [restart addExecutionBlock:^{
 133             __strong __typeof(weakSelf) strongSelf = weakSelf;
 134             if(!strongSelf) {
 135                 secerror("ckksresync: received callback for released object");
 136                 return;
 137             }
 138
 139             if(scan.recordsFound > 0) {
 140                 if(strongSelf.restartCount >= 3) {
 141                     // we've restarted too many times. Fail and stop.
 142                     ckkserror("ckksresync", ckks, "restarted synchronization too often; Failing");
 143                     strongSelf.error = [NSError errorWithDomain:@"securityd"
 144                                                          code:2
 145                                                      userInfo:@{NSLocalizedDescriptionKey: @"resynchronization restarted too many times; churn in database?"}];
 146                 } else {
 147                     // restart the sync operation.
 148                     strongSelf.restartCount += 1;
 149                     ckkserror("ckksresync", ckks, "restarting synchronization operation due to new local items");
 150                     [strongSelf groupStart];
 151                 }
 152             }
 153         }];
 154
 155         [restart addSuccessDependency: scan];
 156         [self runBeforeGroupFinished: restart];
 157
 158         return true;
 159     }];
 160 }
 161
 162 @end;
 163
 164 #endif