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(kvsStoreChangedAsync:)
  53                                                  name:NSUbiquitousKeyValueStoreDidChangeExternallyNotification
  54                                                object:nil];
  55
  56 }
  57
  58 - (void)setObject:(id)obj forKey:(NSString*)key {
  59     secdebug("kvsdebug", "%@ key %@ set to: %@ from: %@", self, key, obj, [self.cloudStore objectForKey:key]);
  60     [self.cloudStore setObject:obj forKey:key];
  61 }
  62
  63 - (NSDictionary<NSString *, id>*) copyAsDictionary {
  64     return [self.cloudStore dictionaryRepresentation];
  65 }
  66
  67 - (void)addEntriesFromDictionary:(NSDictionary<NSString*, NSObject*> *)otherDictionary {
  68     [otherDictionary enumerateKeysAndObjectsUsingBlock:^(NSString * _Nonnull key, NSObject * _Nonnull obj, BOOL * _Nonnull stop) {
  69         [self setObject:obj forKey:key];
  70     }];
  71 }
  72
  73 - (id)objectForKey:(NSString*)key {
  74     return [self.cloudStore objectForKey:key];
  75 }
  76
  77 - (void)removeObjectForKey:(NSString*)key {
  78     return [self.cloudStore removeObjectForKey:key];
  79 }
  80
  81 - (void)removeAllObjects {
  82     [[[[self.cloudStore dictionaryRepresentation] allKeys] copy] enumerateObjectsUsingBlock:^(NSString * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
  83         [self.cloudStore removeObjectForKey:obj];
  84     }];
  85 }
  86
  87 - (void)pushWrites {
  88     [[self cloudStore] synchronize];
  89 }
  90
  91 // Runs on the same thread that posted the notification, and that thread _may_ be the
  92 // kdkvsproxy_queue (see 30470419). Avoid deadlock by bouncing through global queue.
  93 - (void)kvsStoreChangedAsync:(NSNotification *)notification
  94 {
  95     dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
  96         [self kvsStoreChanged:notification];
  97     });
  98 }
  99
 100 - (void) kvsStoreChanged:(NSNotification *)notification {
 101     /*
 102      Posted when the value of one or more keys in the local key-value store
 103      changed due to incoming data pushed from iCloud. This notification is
 104      sent only upon a change received from iCloud; it is not sent when your
 105      app sets a value.
 106
 107      The user info dictionary can contain the reason for the notification as
 108      well as a list of which values changed, as follows:
 109
 110      The value of the NSUbiquitousKeyValueStoreChangeReasonKey key, when
 111      present, indicates why the key-value store changed. Its value is one of
 112      the constants in "Change Reason Values."
 113
 114      The value of the NSUbiquitousKeyValueStoreChangedKeysKey, when present,
 115      is an array of strings, each the name of a key whose value changed. The
 116      notification object is the NSUbiquitousKeyValueStore object whose contents
 117      changed.
 118
 119      NSUbiquitousKeyValueStoreInitialSyncChange is only posted if there is any
 120      local value that has been overwritten by a distant value. If there is no
 121      conflict between the local and the distant values when doing the initial
 122      sync (e.g. if the cloud has no data stored or the client has not stored
 123      any data yet), you'll never see that notification.
 124
 125      NSUbiquitousKeyValueStoreInitialSyncChange implies an initial round trip
 126      with server but initial round trip with server does not imply
 127      NSUbiquitousKeyValueStoreInitialSyncChange.
 128      */
 129     os_activity_initiate("cloudChanged", OS_ACTIVITY_FLAG_DEFAULT, ^{
 130         secdebug(XPROXYSCOPE, "%@ KVS Remote changed notification: %@", self, notification);
 131
 132         NSDictionary *userInfo = [notification userInfo];
 133         NSNumber *reason = [userInfo objectForKey:NSUbiquitousKeyValueStoreChangeReasonKey];
 134         NSArray *keysChangedArray = [userInfo objectForKey:NSUbiquitousKeyValueStoreChangedKeysKey];
 135         NSSet *keysChanged = keysChangedArray ? [NSSet setWithArray: keysChangedArray] : nil;
 136
 137         if (reason) switch ([reason integerValue]) {
 138             case NSUbiquitousKeyValueStoreInitialSyncChange:
 139                 [self.proxy storeKeysChanged: keysChanged initial: YES];
 140                 break;
 141
 142             case NSUbiquitousKeyValueStoreServerChange:
 143                 [self.proxy storeKeysChanged: keysChanged initial: NO];
 144                 break;
 145
 146             case NSUbiquitousKeyValueStoreQuotaViolationChange:
 147                 seccritical("Received NSUbiquitousKeyValueStoreQuotaViolationChange");
 148                 break;
 149
 150             case NSUbiquitousKeyValueStoreAccountChange:
 151                 [self.proxy storeAccountChanged];
 152                 break;
 153
 154             default:
 155                 secinfo("kvsstore", "ignoring unknown notification: %@", reason);
 156                 break;
 157         }
 158     });
 159 }
 160
 161 // try to synchronize asap, and invoke the handler on completion to take incoming changes.
 162
 163 static bool isResubmitError(NSError* error) {
 164     return error && (CFErrorGetCode((__bridge CFErrorRef) error) == UPDATE_RESUBMIT) &&
 165         (CFErrorGetDomain((__bridge CFErrorRef)error) == __SYDErrorKVSDomain);
 166 }
 167
 168 - (BOOL) pullUpdates:(NSError **)failure
 169 {
 170     __block NSError *tempFailure = nil;
 171     const int kMaximumTries = 10;
 172     int tryCount = 0;
 173     // Retry up to 10 times, since we're told this can fail and WE have to deal with it.
 174
 175     dispatch_semaphore_t freshSemaphore = dispatch_semaphore_create(0);
 176
 177     do {
 178         ++tryCount;
 179         secnoticeq("fresh", "%s CALLING OUT TO syncdefaultsd SWCH, try %d: %@", kWAIT2MINID, tryCount, self);
 180
 181         [[self cloudStore] synchronizeWithCompletionHandler:^(NSError *error) {
 182             if (error) {
 183                 tempFailure = error;
 184                 secnotice("fresh", "%s RETURNING FROM syncdefaultsd SWCH: %@: %@", kWAIT2MINID, self, error);
 185             } else {
 186                 secnotice("fresh", "%s RETURNING FROM syncdefaultsd SWCH: %@", kWAIT2MINID, self);
 187                 [[self cloudStore] synchronize]; // Per olivier in <rdar://problem/13412631>, sync before getting values
 188                 secnotice("fresh", "%s RETURNING FROM syncdefaultsd SYNC: %@", kWAIT2MINID, self);
 189             }
 190             dispatch_semaphore_signal(freshSemaphore);
 191         }];
 192         dispatch_semaphore_wait(freshSemaphore, DISPATCH_TIME_FOREVER);
 193     } while (tryCount < kMaximumTries && isResubmitError(tempFailure));
 194
 195     if (isResubmitError(tempFailure)) {
 196         secerrorq("%s %d retry attempts to request freshness exceeded, failing", kWAIT2MINID, tryCount);
 197     }
 198
 199     if (failure && (*failure == NULL)) {
 200         *failure = tempFailure;
 201     }
 202
 203     return tempFailure == nil;
 204 }
 205
 206 @end