keychain/ckks/CKKSLockStateTracker.m

   1 /*
   2  * Copyright (c) 2017 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 #if OCTAGON
  25
  26 #include <notify.h>
  27 #include <dispatch/dispatch.h>
  28 #include <utilities/SecAKSWrappers.h>
  29
  30 #import "keychain/ckks/CKKS.h"
  31 #import "keychain/ckks/CKKSGroupOperation.h"
  32 #import "keychain/ckks/CKKSLockStateTracker.h"
  33
  34 @interface CKKSLockStateTracker ()
  35 @property bool isLocked;
  36 @property dispatch_queue_t queue;
  37 @property NSOperationQueue* operationQueue;
  38 @end
  39
  40 @implementation CKKSLockStateTracker
  41
  42 - (instancetype)init {
  43     if((self = [super init])) {
  44         _queue = dispatch_queue_create("lock-state-tracker", DISPATCH_QUEUE_SERIAL);
  45         _operationQueue = [[NSOperationQueue alloc] init];
  46
  47         _isLocked = true;
  48         [self resetUnlockDependency];
  49
  50         __weak __typeof(self) weakSelf = self;
  51
  52         // If this is a live server, register with notify
  53         if(!SecCKKSTestsEnabled()) {
  54             int token = 0;
  55             notify_register_dispatch(kUserKeybagStateChangeNotification, &token, _queue, ^(int t) {
  56                 [weakSelf _onqueueRecheck];
  57             });
  58         }
  59
  60         dispatch_async(_queue, ^{
  61             [weakSelf _onqueueRecheck];
  62         });
  63     }
  64     return self;
  65 }
  66
  67 -(NSString*)description {
  68     return [NSString stringWithFormat: @"<CKKSLockStateTracker: %@>", self.isLocked ? @"locked" : @"unlocked"];
  69 }
  70
  71 -(void)resetUnlockDependency {
  72     if(self.unlockDependency == nil || ![self.unlockDependency isPending]) {
  73         self.unlockDependency = [NSBlockOperation blockOperationWithBlock: ^{
  74             secinfo("ckks", "Keybag unlocked");
  75         }];
  76         self.unlockDependency.name = @"keybag-unlocked-dependency";
  77     }
  78 }
  79
  80 +(bool)queryAKSLocked {
  81     CFErrorRef aksError = NULL;
  82     bool locked = true;
  83
  84     if(!SecAKSGetIsLocked(&locked, &aksError)) {
  85         secerror("ckks: error querying lock state: %@", aksError);
  86         CFReleaseNull(aksError);
  87     }
  88
  89     return locked;
  90 }
  91
  92 -(void)_onqueueRecheck {
  93     dispatch_assert_queue(self.queue);
  94
  95     bool wasLocked = self.isLocked;
  96     self.isLocked = [CKKSLockStateTracker queryAKSLocked];
  97
  98     if(wasLocked != self.isLocked) {
  99         if(self.isLocked) {
 100             // We're locked now.
 101             [self resetUnlockDependency];
 102         } else {
 103             [self.operationQueue addOperation: self.unlockDependency];
 104             self.unlockDependency = nil;
 105         }
 106     }
 107 }
 108
 109 -(void)recheck {
 110     dispatch_sync(self.queue, ^{
 111         [self _onqueueRecheck];
 112     });
 113 }
 114
 115 -(bool)isLockedError:(NSError *)error {
 116     return [error.domain isEqualToString:@"securityd"] && error.code == errSecInteractionNotAllowed;
 117 }
 118
 119
 120 @end
 121
 122 #endif // OCTAGON