KVSKeychainSyncingProxy/CKDKVSStore.m

   1 //
   2 //  CKDKVSStore.m
   3 //  Security
   4 //
   5 //  Created by Mitch Adler on 5/15/16.
   6 //
   7 //
   8
   9 #import "CKDKVSStore.h"
  10 #import "CKDKVSProxy.h"
  11
  12 #include "SOSCloudKeychainConstants.h"
  13 #include <utilities/debugging.h>
  14
  15 #import <Foundation/NSUbiquitousKeyValueStore.h>
  16 #import <Foundation/NSUbiquitousKeyValueStore_Private.h>
  17 #import "SyncedDefaults/SYDConstants.h"
  18 #include <os/activity.h>
  19
  20 //KVS error codes
  21 #define UPDATE_RESUBMIT 4
  22
  23 @interface CKDKVSStore ()
  24 @property (readwrite, weak) UbiqitousKVSProxy* proxy;
  25 @property (readwrite) NSUbiquitousKeyValueStore* cloudStore;
  26 @end
  27
  28 @implementation CKDKVSStore
  29
  30 + (instancetype)kvsInterface {
  31     return [[CKDKVSStore alloc] init];
  32 }
  33
  34 - (instancetype)init {
  35     self = [super init];
  36
  37     self->_cloudStore = [NSUbiquitousKeyValueStore defaultStore];
  38     self->_proxy = nil;
  39
  40     if (!self.cloudStore) {
  41         secerror("NO NSUbiquitousKeyValueStore defaultStore!!!");
  42         return nil;
  43     }
  44
  45     return self;
  46 }
  47
  48 - (void) connectToProxy: (UbiqitousKVSProxy*) proxy {
  49     _proxy = proxy;
  50
  51     [[NSNotificationCenter defaultCenter] addObserver:self
  52                                              selector:@selector(kvsStoreChanged:)
  53                                                  name:NSUbiquitousKeyValueStoreDidChangeExternallyNotification
  54                                                object:nil];
  55
  56 }
  57
  58 - (void)setObject:(id)obj forKey:(NSString*)key {
  59     NSUbiquitousKeyValueStore *store = [self cloudStore];
  60     if (store)
  61     {
  62         id value = [store objectForKey:key];
  63         if (value)
  64             secdebug("kvsdebug", "%@ key %@ changed: %@ to: %@", self, key, value, obj);
  65         else
  66             secdebug("kvsdebug", "%@ key %@ initialized to: %@", self, key, obj);
  67         [store setObject:obj forKey:key];
  68         [self pushWrites];
  69     } else {
  70         secerror("Can't get kvs store, key: %@ not set to: %@", key, obj);
  71     }
  72 }
  73
  74 - (NSDictionary<NSString *, id>*) copyAsDictionary {
  75     return [self.cloudStore dictionaryRepresentation];
  76 }
  77
  78 - (void)addEntriesFromDictionary:(NSDictionary<NSString*, NSObject*> *)otherDictionary {
  79     [otherDictionary enumerateKeysAndObjectsUsingBlock:^(NSString * _Nonnull key, NSObject * _Nonnull obj, BOOL * _Nonnull stop) {
  80         [self setObject:obj forKey:key];
  81     }];
  82 }
  83
  84 - (id)objectForKey:(NSString*)key {
  85     return [self.cloudStore objectForKey:key];
  86 }
  87
  88 - (void)removeObjectForKey:(NSString*)key {
  89     return [self.cloudStore removeObjectForKey:key];
  90 }
  91
  92 - (void)removeAllObjects {
  93     [[[[self.cloudStore dictionaryRepresentation] allKeys] copy] enumerateObjectsUsingBlock:^(NSString * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
  94         [self.cloudStore removeObjectForKey:obj];
  95     }];
  96 }
  97
  98 - (void)pushWrites {
  99     [[self cloudStore] synchronize];
 100 }
 101
 102 - (void) kvsStoreChanged:(NSNotification *)notification {
 103     /*
 104      Posted when the value of one or more keys in the local key-value store
 105      changed due to incoming data pushed from iCloud. This notification is
 106      sent only upon a change received from iCloud; it is not sent when your
 107      app sets a value.
 108
 109      The user info dictionary can contain the reason for the notification as
 110      well as a list of which values changed, as follows:
 111
 112      The value of the NSUbiquitousKeyValueStoreChangeReasonKey key, when
 113      present, indicates why the key-value store changed. Its value is one of
 114      the constants in "Change Reason Values."
 115
 116      The value of the NSUbiquitousKeyValueStoreChangedKeysKey, when present,
 117      is an array of strings, each the name of a key whose value changed. The
 118      notification object is the NSUbiquitousKeyValueStore object whose contents
 119      changed.
 120
 121      NSUbiquitousKeyValueStoreInitialSyncChange is only posted if there is any
 122      local value that has been overwritten by a distant value. If there is no
 123      conflict between the local and the distant values when doing the initial
 124      sync (e.g. if the cloud has no data stored or the client has not stored
 125      any data yet), you'll never see that notification.
 126
 127      NSUbiquitousKeyValueStoreInitialSyncChange implies an initial round trip
 128      with server but initial round trip with server does not imply
 129      NSUbiquitousKeyValueStoreInitialSyncChange.
 130      */
 131     os_activity_initiate("cloudChanged", OS_ACTIVITY_FLAG_DEFAULT, ^{
 132         secdebug(XPROXYSCOPE, "%@ KVS Remote changed notification: %@", self, notification);
 133
 134         NSDictionary *userInfo = [notification userInfo];
 135         NSNumber *reason = [userInfo objectForKey:NSUbiquitousKeyValueStoreChangeReasonKey];
 136         NSArray *keysChangedArray = [userInfo objectForKey:NSUbiquitousKeyValueStoreChangedKeysKey];
 137         NSSet *keysChanged = keysChangedArray ? [NSSet setWithArray: keysChangedArray] : nil;
 138
 139         if (reason) switch ([reason integerValue]) {
 140             case NSUbiquitousKeyValueStoreInitialSyncChange:
 141                 [self.proxy storeKeysChanged: keysChanged initial: YES];
 142                 break;
 143
 144             case NSUbiquitousKeyValueStoreServerChange:
 145                 [self.proxy storeKeysChanged: keysChanged initial: NO];
 146                 break;
 147
 148             case NSUbiquitousKeyValueStoreQuotaViolationChange:
 149                 seccritical("Received NSUbiquitousKeyValueStoreQuotaViolationChange");
 150                 break;
 151
 152             case NSUbiquitousKeyValueStoreAccountChange:
 153                 [self.proxy storeAccountChanged];
 154                 break;
 155
 156             default:
 157                 secinfo("kvsstore", "ignoring unknown notification: %@", reason);
 158                 break;
 159         }
 160     });
 161 }
 162
 163 // try to synchronize asap, and invoke the handler on completion to take incoming changes.
 164
 165 static bool isResubmitError(NSError* error) {
 166     return error && (CFErrorGetCode((__bridge CFErrorRef) error) == UPDATE_RESUBMIT) &&
 167         (CFErrorGetDomain((__bridge CFErrorRef)error) == __SYDErrorKVSDomain);
 168 }
 169
 170 - (BOOL) pullUpdates:(NSError **)failure
 171 {
 172     __block NSError *tempFailure = nil;
 173     const int kMaximumTries = 10;
 174     int tryCount = 0;
 175     // Retry up to 10 times, since we're told this can fail and WE have to deal with it.
 176
 177     dispatch_semaphore_t freshSemaphore = dispatch_semaphore_create(0);
 178
 179     do {
 180         ++tryCount;
 181         secnoticeq("fresh", "%s CALLING OUT TO syncdefaultsd SWCH, try %d: %@", kWAIT2MINID, tryCount, self);
 182
 183         [[self cloudStore] synchronizeWithCompletionHandler:^(NSError *error) {
 184             if (error) {
 185                 tempFailure = error;
 186                 secnotice("fresh", "%s RETURNING FROM syncdefaultsd SWCH: %@: %@", kWAIT2MINID, self, error);
 187             } else {
 188                 secnotice("fresh", "%s RETURNING FROM syncdefaultsd SWCH: %@", kWAIT2MINID, self);
 189                 [[self cloudStore] synchronize]; // Per olivier in <rdar://problem/13412631>, sync before getting values
 190                 secnotice("fresh", "%s RETURNING FROM syncdefaultsd SYNC: %@", kWAIT2MINID, self);
 191             }
 192             dispatch_semaphore_signal(freshSemaphore);
 193         }];
 194         dispatch_semaphore_wait(freshSemaphore, DISPATCH_TIME_FOREVER);
 195     } while (tryCount < kMaximumTries && isResubmitError(tempFailure));
 196
 197     if (isResubmitError(tempFailure)) {
 198         secerrorq("%s %d retry attempts to request freshness exceeded, failing", kWAIT2MINID, tryCount);
 199     }
 200
 201     if (failure && (*failure == NULL)) {
 202         *failure = tempFailure;
 203     }
 204
 205     return tempFailure == nil;
 206 }
 207
 208 @end