keychain/securityd/SecDbKeychainItemV7.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 #import "SecDbKeychainItemV7.h"
  25 #import "SecKeybagSupport.h"
  26 #import "SecItemServer.h"
  27 #import "SecAccessControl.h"
  28 #import "SecDbKeychainSerializedItemV7.h"
  29 #import "SecDbKeychainSerializedAKSWrappedKey.h"
  30 #import "SecDbKeychainSerializedMetadata.h"
  31 #import "SecDbKeychainSerializedSecretData.h"
  32 #import <dispatch/dispatch.h>
  33 #import <utilities/SecAKSWrappers.h>
  34 #import "SecAKSObjCWrappers.h"
  35 #import <utilities/der_plist.h>
  36 #import <SecurityFoundation/SFEncryptionOperation.h>
  37 #import <SecurityFoundation/SFKey_Private.h>
  38 #import <SecurityFoundation/SFCryptoServicesErrors.h>
  39
  40 #import <Foundation/NSKeyedArchiver_Private.h>
  41
  42 #if USE_KEYSTORE && __has_include(<Kernel/IOKit/crypto/AppleKeyStoreDefs.h>)
  43 #import <Kernel/IOKit/crypto/AppleKeyStoreDefs.h>
  44 #endif
  45
  46 #import "SecDbKeychainMetadataKeyStore.h"
  47 #import "SecDbBackupManager.h"
  48
  49 #define KEYCHAIN_ITEM_PADDING_MODULUS 20
  50
  51 // See corresponding "reasonable size" client-side limit(s) in SecItem.
  52
  53 // Generally the secret data dictionary contains a single key
  54 // with the client's password/key NSData therein, so 4k feels extremely luxurious
  55 #define REASONABLE_SECRET_DATA_SIZE 4096
  56
  57 // This feels similarly generous, but let's find out
  58 #define REASONABLE_METADATA_SIZE 2048
  59
  60 NSString* const SecDbKeychainErrorDomain = @"SecDbKeychainErrorDomain";
  61 const NSInteger SecDbKeychainErrorDeserializationFailed = 1;
  62
  63 static NSString* const SecDBTamperCheck = @"TamperCheck";
  64
  65 static NSDictionary* dictionaryFromDERData(NSData* data)
  66 {
  67     NSDictionary* dict = (__bridge_transfer NSDictionary*)CFPropertyListCreateWithDERData(NULL, (__bridge CFDataRef)data, 0, NULL, NULL);
  68     return [dict isKindOfClass:[NSDictionary class]] ? dict : nil;
  69 }
  70
  71 typedef NS_ENUM(uint32_t, SecDbKeychainAKSWrappedKeyType) {
  72     SecDbKeychainAKSWrappedKeyTypeRegular,
  73     SecDbKeychainAKSWrappedKeyTypeRefKey
  74 };
  75
  76 @interface SecDbKeychainAKSWrappedKey : NSObject
  77
  78 @property (readonly) NSData* wrappedKey;
  79 @property (readonly) NSData* refKeyBlob;
  80 @property (readonly) SecDbKeychainAKSWrappedKeyType type;
  81
  82 @property (readonly) NSData* serializedRepresentation;
  83
  84 - (instancetype)initWithData:(NSData*)data;
  85 - (instancetype)initRegularWrappedKeyWithData:(NSData*)wrappedKey;
  86 - (instancetype)initRefKeyWrappedKeyWithData:(NSData*)wrappedKey refKeyBlob:(NSData*)refKeyBlob;
  87
  88 @end
  89
  90 @interface SecDbKeychainMetadata : NSObject
  91
  92 @property (readonly) SFAuthenticatedCiphertext* ciphertext;
  93 @property (readonly) SFAuthenticatedCiphertext* wrappedKey;
  94 @property (readonly) NSString* tamperCheck;
  95
  96 @property (readonly) NSData* serializedRepresentation;
  97
  98 - (instancetype)initWithData:(NSData*)data;
  99 - (instancetype)initWithCiphertext:(SFAuthenticatedCiphertext*)ciphertext wrappedKey:(SFAuthenticatedCiphertext*)wrappedKey tamperCheck:(NSString*)tamperCheck error:(NSError**)error;
 100
 101 @end
 102
 103 @interface SecDbKeychainSecretData : NSObject
 104
 105 @property (readonly) SFAuthenticatedCiphertext* ciphertext;
 106 @property (readonly) SecDbKeychainAKSWrappedKey* wrappedKey;
 107 @property (readonly) NSString* tamperCheck;
 108
 109 @property (readonly) NSData* serializedRepresentation;
 110
 111 - (instancetype)initWithData:(NSData*)data;
 112 - (instancetype)initWithCiphertext:(SFAuthenticatedCiphertext*)ciphertext wrappedKey:(SecDbKeychainAKSWrappedKey*)wrappedKey tamperCheck:(NSString*)tamperCheck backupWrappedKey:(SecDbBackupWrappedItemKey*)backupWrappedKey error:(NSError**)error;
 113
 114 @end
 115
 116 @implementation SecDbKeychainAKSWrappedKey {
 117     SecDbKeychainSerializedAKSWrappedKey* _serializedHolder;
 118 }
 119
 120 - (instancetype)initRegularWrappedKeyWithData:(NSData*)wrappedKey
 121 {
 122     if (self = [super init]) {
 123         _serializedHolder = [[SecDbKeychainSerializedAKSWrappedKey alloc] init];
 124         _serializedHolder.wrappedKey = wrappedKey;
 125         _serializedHolder.type = SecDbKeychainAKSWrappedKeyTypeRegular;
 126     }
 127
 128     return self;
 129 }
 130
 131 - (instancetype)initRefKeyWrappedKeyWithData:(NSData*)wrappedKey refKeyBlob:(NSData*)refKeyBlob
 132 {
 133     if (self = [super init]) {
 134         _serializedHolder = [[SecDbKeychainSerializedAKSWrappedKey alloc] init];
 135         _serializedHolder.wrappedKey = wrappedKey;
 136         _serializedHolder.refKeyBlob = refKeyBlob;
 137         _serializedHolder.type = SecDbKeychainAKSWrappedKeyTypeRefKey;
 138     }
 139
 140     return self;
 141 }
 142
 143 - (instancetype)initWithData:(NSData*)data
 144 {
 145     if (self = [super init]) {
 146         _serializedHolder = [[SecDbKeychainSerializedAKSWrappedKey alloc] initWithData:data];
 147         if (!_serializedHolder.wrappedKey || (_serializedHolder.type == SecDbKeychainAKSWrappedKeyTypeRefKey && !_serializedHolder.refKeyBlob)) {
 148             self = nil;
 149         }
 150     }
 151
 152     return self;
 153 }
 154
 155 - (NSData*)serializedRepresentation
 156 {
 157     return _serializedHolder.data;
 158 }
 159
 160 - (NSData*)wrappedKey
 161 {
 162     return _serializedHolder.wrappedKey;
 163 }
 164
 165 - (NSData*)refKeyBlob
 166 {
 167     return _serializedHolder.refKeyBlob;
 168 }
 169
 170 - (SecDbKeychainAKSWrappedKeyType)type
 171 {
 172     return _serializedHolder.type;
 173 }
 174
 175 @end
 176
 177 @implementation SecDbKeychainMetadata {
 178     SecDbKeychainSerializedMetadata* _serializedHolder;
 179 }
 180
 181 - (instancetype)initWithCiphertext:(SFAuthenticatedCiphertext*)ciphertext
 182                         wrappedKey:(SFAuthenticatedCiphertext*)wrappedKey
 183                        tamperCheck:(NSString*)tamperCheck
 184                              error:(NSError**)error
 185 {
 186     if (self = [super init]) {
 187         _serializedHolder = [[SecDbKeychainSerializedMetadata alloc] init];
 188         _serializedHolder.ciphertext = [NSKeyedArchiver archivedDataWithRootObject:ciphertext requiringSecureCoding:YES error:error];
 189         _serializedHolder.wrappedKey = [NSKeyedArchiver archivedDataWithRootObject:wrappedKey requiringSecureCoding:YES error:error];
 190         _serializedHolder.tamperCheck = tamperCheck;
 191         if (!_serializedHolder.ciphertext || !_serializedHolder.wrappedKey || !_serializedHolder.tamperCheck) {
 192             self = nil;
 193         }
 194     }
 195
 196     return self;
 197 }
 198
 199 - (instancetype)initWithData:(NSData*)data
 200 {
 201     if (self = [super init]) {
 202         _serializedHolder = [[SecDbKeychainSerializedMetadata alloc] initWithData:data];
 203         if (!_serializedHolder.ciphertext || !_serializedHolder.wrappedKey || !_serializedHolder.tamperCheck) {
 204             self = nil;
 205         }
 206     }
 207
 208     return self;
 209 }
 210
 211 - (NSData*)serializedRepresentation
 212 {
 213     return _serializedHolder.data;
 214 }
 215
 216 - (SFAuthenticatedCiphertext*)ciphertext
 217 {
 218     NSError* error = nil;
 219     SFAuthenticatedCiphertext* ciphertext =  [NSKeyedUnarchiver unarchivedObjectOfClass:[SFAuthenticatedCiphertext class] fromData:_serializedHolder.ciphertext error:&error];
 220     if (!ciphertext) {
 221         secerror("SecDbKeychainItemV7: error deserializing ciphertext from metadata: %@", error);
 222     }
 223
 224     return ciphertext;
 225 }
 226
 227 - (SFAuthenticatedCiphertext*)wrappedKey
 228 {
 229     NSError* error = nil;
 230     SFAuthenticatedCiphertext* wrappedKey =  [NSKeyedUnarchiver unarchivedObjectOfClass:[SFAuthenticatedCiphertext class] fromData:_serializedHolder.wrappedKey error:&error];
 231     if (!wrappedKey) {
 232         secerror("SecDbKeychainItemV7: error deserializing wrappedKey from metadata: %@", error);
 233     }
 234
 235     return wrappedKey;
 236 }
 237
 238 - (NSString*)tamperCheck
 239 {
 240     return _serializedHolder.tamperCheck;
 241 }
 242
 243 @end
 244
 245 @implementation SecDbKeychainSecretData {
 246     SecDbKeychainSerializedSecretData* _serializedHolder;
 247 }
 248
 249 - (instancetype)initWithCiphertext:(SFAuthenticatedCiphertext*)ciphertext
 250                         wrappedKey:(SecDbKeychainAKSWrappedKey*)wrappedKey
 251                        tamperCheck:(NSString*)tamperCheck
 252                   backupWrappedKey:(SecDbBackupWrappedItemKey*)backupWrappedKey
 253                              error:(NSError**)error
 254 {
 255     if (self = [super init]) {
 256         _serializedHolder = [[SecDbKeychainSerializedSecretData alloc] init];
 257         _serializedHolder.ciphertext = [NSKeyedArchiver archivedDataWithRootObject:ciphertext requiringSecureCoding:YES error:error];
 258         _serializedHolder.wrappedKey = wrappedKey.serializedRepresentation;
 259         _serializedHolder.tamperCheck = tamperCheck;
 260         _serializedHolder.secDbBackupWrappedItemKey = backupWrappedKey ? [NSKeyedArchiver archivedDataWithRootObject:backupWrappedKey requiringSecureCoding:YES error:error] : nil;
 261         if (!_serializedHolder.ciphertext || !_serializedHolder.wrappedKey || !_serializedHolder.tamperCheck) {
 262             self = nil;
 263         }
 264     }
 265
 266     return self;
 267 }
 268
 269 - (instancetype)initWithData:(NSData*)data
 270 {
 271     if (self = [super init]) {
 272         _serializedHolder = [[SecDbKeychainSerializedSecretData alloc] initWithData:data];
 273         if (!_serializedHolder.ciphertext || !_serializedHolder.wrappedKey || !_serializedHolder.tamperCheck) {
 274             self = nil;
 275         }
 276     }
 277
 278     return self;
 279 }
 280
 281 - (NSData*)serializedRepresentation
 282 {
 283     return _serializedHolder.data;
 284 }
 285
 286 - (SFAuthenticatedCiphertext*)ciphertext
 287 {
 288     NSError* error = nil;
 289     SFAuthenticatedCiphertext* ciphertext =  [NSKeyedUnarchiver unarchivedObjectOfClass:[SFAuthenticatedCiphertext class] fromData:_serializedHolder.ciphertext error:&error];
 290     if (!ciphertext) {
 291         secerror("SecDbKeychainItemV7: error deserializing ciphertext from secret data: %@", error);
 292     }
 293
 294     return ciphertext;
 295 }
 296
 297 - (SecDbKeychainAKSWrappedKey*)wrappedKey
 298 {
 299     return [[SecDbKeychainAKSWrappedKey alloc] initWithData:_serializedHolder.wrappedKey];
 300 }
 301
 302 - (NSString*)tamperCheck
 303 {
 304     return _serializedHolder.tamperCheck;
 305 }
 306
 307 @end
 308
 309 @interface SecDbKeychainItemV7 ()
 310 @property (nonatomic) NSData* backupUUID;
 311 @end;
 312
 313 @implementation SecDbKeychainItemV7 {
 314     SecDbKeychainSecretData* _encryptedSecretData;
 315     SecDbKeychainMetadata* _encryptedMetadata;
 316     NSDictionary* _secretAttributes;
 317     NSDictionary* _metadataAttributes;
 318     NSString* _tamperCheck;
 319     keyclass_t _keyclass;
 320     keybag_handle_t _keybag;
 321 }
 322
 323 @synthesize keyclass = _keyclass;
 324
 325 // bring back with <rdar://problem/37523001>
 326 #if 0
 327 + (bool)isKeychainUnlocked
 328 {
 329     return kc_is_unlocked();
 330 }
 331 #endif
 332
 333 - (instancetype)initWithData:(NSData*)data decryptionKeybag:(keybag_handle_t)decryptionKeybag error:(NSError**)error
 334 {
 335     if (self = [super init]) {
 336         SecDbKeychainSerializedItemV7* serializedItem = [[SecDbKeychainSerializedItemV7 alloc] initWithData:data];
 337         if (serializedItem) {
 338
 339             // Add 10% for serializing overhead. We're trying to catch blatant overstuffing, not enforce hard limits
 340             if (data.length > ((REASONABLE_SECRET_DATA_SIZE + REASONABLE_METADATA_SIZE) * 1.1)) {
 341                 secwarning("SecDbKeychainItemV7: serialized item exceeds reasonable size (%lu bytes)", (unsigned long)data.length);
 342             }
 343
 344             _keybag = decryptionKeybag;
 345             _encryptedSecretData = [[SecDbKeychainSecretData alloc] initWithData:serializedItem.encryptedSecretData];
 346             _encryptedMetadata = [[SecDbKeychainMetadata alloc] initWithData:serializedItem.encryptedMetadata];
 347             _keyclass = serializedItem.keyclass;
 348             if (![_encryptedSecretData.tamperCheck isEqualToString:_encryptedMetadata.tamperCheck]) {
 349                 self = nil;
 350             }
 351         }
 352         else {
 353             self = nil;
 354         }
 355     }
 356
 357     if (!self && error) {
 358         *error = [NSError errorWithDomain:(id)kCFErrorDomainOSStatus code:errSecDecode userInfo:@{NSLocalizedDescriptionKey : @"failed to deserialize keychain item blob"}];
 359     }
 360
 361     return self;
 362 }
 363
 364 - (instancetype)initWithSecretAttributes:(NSDictionary*)secretAttributes metadataAttributes:(NSDictionary*)metadataAttributes tamperCheck:(NSString*)tamperCheck keyclass:(keyclass_t)keyclass
 365 {
 366     NSParameterAssert(tamperCheck);
 367
 368     if (self = [super init]) {
 369         _secretAttributes = secretAttributes ? secretAttributes.copy : [NSDictionary dictionary];
 370         _metadataAttributes = metadataAttributes ? metadataAttributes.copy : [NSDictionary dictionary];
 371         _tamperCheck = tamperCheck.copy;
 372         _keyclass = keyclass;
 373     }
 374
 375     return self;
 376 }
 377
 378 + (SFAESKeySpecifier*)keySpecifier
 379 {
 380     static SFAESKeySpecifier* keySpecifier = nil;
 381     static dispatch_once_t onceToken;
 382     dispatch_once(&onceToken, ^{
 383         keySpecifier = [[SFAESKeySpecifier alloc] initWithBitSize:SFAESKeyBitSize256];
 384     });
 385
 386     return keySpecifier;
 387 }
 388
 389 + (SFAuthenticatedEncryptionOperation*)encryptionOperation
 390 {
 391     static SFAuthenticatedEncryptionOperation* encryptionOperation = nil;
 392     static dispatch_once_t onceToken;
 393     dispatch_once(&onceToken, ^{
 394         encryptionOperation = [[SFAuthenticatedEncryptionOperation alloc] initWithKeySpecifier:[self keySpecifier]];
 395     });
 396
 397     return encryptionOperation;
 398 }
 399
 400 + (SFAuthenticatedEncryptionOperation*)decryptionOperation
 401 {
 402     static SFAuthenticatedEncryptionOperation* decryptionOperation = nil;
 403     static dispatch_once_t onceToken;
 404     dispatch_once(&onceToken, ^{
 405         decryptionOperation = [[SFAuthenticatedEncryptionOperation alloc] initWithKeySpecifier:[self keySpecifier]];
 406     });
 407
 408     return decryptionOperation;
 409 }
 410
 411 - (NSDictionary*)metadataAttributesWithError:(NSError**)error
 412 {
 413     if (!_metadataAttributes) {
 414         SFAESKey* metadataClassKey = [self metadataClassKeyWithKeybag:_keybag
 415                                                    createKeyIfMissing:false
 416                                                   overwriteCorruptKey:false
 417                                                                 error:error];
 418         if (metadataClassKey) {
 419             NSError* localError = nil;
 420             NSData* keyData = [[self.class decryptionOperation] decrypt:_encryptedMetadata.wrappedKey withKey:metadataClassKey error:&localError];
 421             if (!keyData) {
 422                 secerror("SecDbKeychainItemV7: error unwrapping item metadata key (class %d, bag %d): %@", (int)self.keyclass, _keybag, localError);
 423                 // TODO: track this in LocalKeychainAnalytics
 424                 if (error) {
 425                     CFErrorRef secError = (CFErrorRef)CFBridgingRetain(localError); // this makes localError become the underlying error
 426                     SecError(errSecDecode, &secError, CFSTR("failed to unwrap item metadata key"));
 427                     *error = CFBridgingRelease(secError);
 428                 }
 429                 return nil;
 430             }
 431             SFAESKey* key = [[SFAESKey alloc] initWithData:keyData specifier:[self.class keySpecifier] error:error];
 432             if (!key) {
 433                 return nil;
 434             }
 435
 436             NSData* metadata = [[self.class decryptionOperation] decrypt:_encryptedMetadata.ciphertext withKey:key error:&localError];
 437             if (!metadata) {
 438                 secerror("SecDbKeychainItemV7: error decrypting metadata content: %@", localError);
 439                 if (error) {
 440                     CFErrorRef secError = (CFErrorRef)CFBridgingRetain(localError); // this makes localError become the underlying error
 441                     SecError(errSecDecode, &secError, CFSTR("failed to decrypt item metadata contents"));
 442                     *error = CFBridgingRelease(secError);
 443                 }
 444                 return nil;
 445             }
 446             NSMutableDictionary* decryptedAttributes = dictionaryFromDERData(metadata).mutableCopy;
 447             NSString* tamperCheck = decryptedAttributes[SecDBTamperCheck];
 448             if ([tamperCheck isEqualToString:_encryptedMetadata.tamperCheck]) {
 449                 [decryptedAttributes removeObjectForKey:SecDBTamperCheck];
 450                 _metadataAttributes = decryptedAttributes;
 451             }
 452             else {
 453                 secerror("SecDbKeychainItemV7: tamper check failed for metadata decryption, expected %@ found %@", tamperCheck, _encryptedMetadata.tamperCheck);
 454                 if (error) {
 455                     CFErrorRef secError = NULL;
 456                     SecError(errSecDecode, &secError, CFSTR("tamper check failed for metadata decryption"));
 457                     *error = CFBridgingRelease(secError);
 458                 }
 459             }
 460         }
 461     }
 462
 463     return _metadataAttributes;
 464 }
 465
 466 - (NSDictionary*)secretAttributesWithAcmContext:(NSData*)acmContext accessControl:(SecAccessControlRef)accessControl callerAccessGroups:(NSArray*)callerAccessGroups error:(NSError**)error
 467 {
 468     if (!_secretAttributes) {
 469         SFAESKey* key = [self unwrapFromAKS:_encryptedSecretData.wrappedKey accessControl:accessControl acmContext:acmContext callerAccessGroups:callerAccessGroups delete:NO error:error];
 470         if (key) {
 471             NSError* localError = nil;
 472             NSData* secretDataWithPadding = [[self.class decryptionOperation] decrypt:_encryptedSecretData.ciphertext withKey:key error:&localError];
 473             if (!secretDataWithPadding) {
 474                 secerror("SecDbKeychainItemV7: error decrypting item secret data contents: %@", localError);
 475                 if (error) {
 476                     CFErrorRef secError = (CFErrorRef)CFBridgingRetain(localError); // this makes localError become the underlying error
 477                     SecError(errSecDecode, &secError, CFSTR("error decrypting item secret data contents"));
 478                     *error = CFBridgingRelease(secError);
 479                 }
 480                 return nil;
 481             }
 482             int8_t paddingLength = *((int8_t*)secretDataWithPadding.bytes + secretDataWithPadding.length - 1);
 483             NSData* secretDataWithoutPadding = [secretDataWithPadding subdataWithRange:NSMakeRange(0, secretDataWithPadding.length - paddingLength)];
 484
 485             NSMutableDictionary* decryptedAttributes = dictionaryFromDERData(secretDataWithoutPadding).mutableCopy;
 486             NSString* tamperCheck = decryptedAttributes[SecDBTamperCheck];
 487             if ([tamperCheck isEqualToString:_encryptedSecretData.tamperCheck]) {
 488                 [decryptedAttributes removeObjectForKey:SecDBTamperCheck];
 489                 _secretAttributes = decryptedAttributes;
 490             }
 491             else {
 492                 secerror("SecDbKeychainItemV7: tamper check failed for secret data decryption, expected %@ found %@", tamperCheck, _encryptedMetadata.tamperCheck);
 493             }
 494         }
 495     }
 496
 497     return _secretAttributes;
 498 }
 499
 500 - (BOOL)deleteWithAcmContext:(NSData*)acmContext accessControl:(SecAccessControlRef)accessControl callerAccessGroups:(NSArray*)callerAccessGroups error:(NSError**)error
 501 {
 502     NSError* localError = nil;
 503     (void)[self unwrapFromAKS:_encryptedSecretData.wrappedKey accessControl:accessControl acmContext:acmContext callerAccessGroups:callerAccessGroups delete:YES error:&localError];
 504     if (localError) {
 505         secerror("SecDbKeychainItemV7: failed to delete item secret key from aks");
 506         if (error) {
 507             *error = localError;
 508         }
 509
 510         return NO;
 511     }
 512
 513     return YES;
 514 }
 515
 516 - (NSData*)encryptedBlobWithKeybag:(keybag_handle_t)keybag accessControl:(SecAccessControlRef)accessControl acmContext:(NSData*)acmContext error:(NSError**)error
 517 {
 518     NSError* localError = nil;
 519     BOOL success = [self encryptMetadataWithKeybag:keybag error:&localError];
 520     if (!success || !_encryptedMetadata || localError) {
 521         if (error) {
 522             *error = localError;
 523         }
 524         return nil;
 525     }
 526
 527     success = [self encryptSecretDataWithKeybag:keybag accessControl:accessControl acmContext:acmContext error:&localError];
 528     if (!success || !_encryptedSecretData || localError) {
 529         if (error) {
 530             *error = localError;
 531         }
 532         return nil;
 533     }
 534
 535     SecDbKeychainSerializedItemV7* serializedItem = [[SecDbKeychainSerializedItemV7 alloc] init];
 536     serializedItem.encryptedMetadata = self.encryptedMetadataBlob;
 537     serializedItem.encryptedSecretData = self.encryptedSecretDataBlob;
 538     serializedItem.keyclass = _keyclass;
 539     return serializedItem.data;
 540 }
 541
 542 - (NSData*)encryptedMetadataBlob
 543 {
 544     return _encryptedMetadata.serializedRepresentation;
 545 }
 546
 547 - (NSData*)encryptedSecretDataBlob
 548 {
 549     return _encryptedSecretData.serializedRepresentation;
 550 }
 551
 552 - (BOOL)encryptMetadataWithKeybag:(keybag_handle_t)keybag error:(NSError**)error
 553 {
 554     SFAESKey* key = [[SFAESKey alloc] initRandomKeyWithSpecifier:[self.class keySpecifier] error:error];
 555     if (!key) {
 556         return NO;
 557     }
 558     SFAuthenticatedEncryptionOperation* encryptionOperation = [self.class encryptionOperation];
 559
 560     NSMutableDictionary* attributesToEncrypt = _metadataAttributes.mutableCopy;
 561     attributesToEncrypt[SecDBTamperCheck] = _tamperCheck;
 562     NSData* metadata = (__bridge_transfer NSData*)CFPropertyListCreateDERData(NULL, (__bridge CFDictionaryRef)attributesToEncrypt, NULL);
 563
 564     if (metadata.length > REASONABLE_METADATA_SIZE) {
 565         NSString *agrp = _metadataAttributes[(__bridge NSString *)kSecAttrAccessGroup];
 566         secwarning("SecDbKeychainItemV7: item's metadata exceeds reasonable size (%lu bytes) (%@)", (unsigned long)metadata.length, agrp);
 567     }
 568
 569     SFAuthenticatedCiphertext* ciphertext = [encryptionOperation encrypt:metadata withKey:key error:error];
 570
 571     SFAESKey* metadataClassKey = [self metadataClassKeyWithKeybag:keybag
 572                                                createKeyIfMissing:true
 573                                               overwriteCorruptKey:true
 574                                                             error:error];
 575     if (metadataClassKey) {
 576         SFAuthenticatedCiphertext* wrappedKey = [encryptionOperation encrypt:key.keyData withKey:metadataClassKey error:error];
 577         _encryptedMetadata = [[SecDbKeychainMetadata alloc] initWithCiphertext:ciphertext wrappedKey:wrappedKey tamperCheck:_tamperCheck error:error];
 578     }
 579
 580     return _encryptedMetadata != nil;
 581 }
 582
 583 - (BOOL)encryptSecretDataWithKeybag:(keybag_handle_t)keybag accessControl:(SecAccessControlRef)accessControl acmContext:(NSData*)acmContext error:(NSError**)error
 584 {
 585     SFAESKey* key = [[SFAESKey alloc] initRandomKeyWithSpecifier:[self.class keySpecifier] error:error];
 586     if (!key) {
 587         return NO;
 588     }
 589     SFAuthenticatedEncryptionOperation* encryptionOperation = [self.class encryptionOperation];
 590
 591     NSMutableDictionary* attributesToEncrypt = _secretAttributes.mutableCopy;
 592     attributesToEncrypt[SecDBTamperCheck] = _tamperCheck;
 593     NSMutableData* secretData = [(__bridge_transfer NSData*)CFPropertyListCreateDERData(NULL, (__bridge CFDictionaryRef)attributesToEncrypt, NULL) mutableCopy];
 594
 595     if (secretData.length > REASONABLE_SECRET_DATA_SIZE) {
 596         NSString *agrp = _metadataAttributes[(__bridge NSString *)kSecAttrAccessGroup];
 597         secwarning("SecDbKeychainItemV7: item's secret data exceeds reasonable size (%lu bytes) (%@)", (unsigned long)secretData.length, agrp);
 598     }
 599
 600     int8_t paddingLength = KEYCHAIN_ITEM_PADDING_MODULUS - (secretData.length % KEYCHAIN_ITEM_PADDING_MODULUS);
 601     int8_t paddingBytes[KEYCHAIN_ITEM_PADDING_MODULUS];
 602     for (int i = 0; i < KEYCHAIN_ITEM_PADDING_MODULUS; i++) {
 603         paddingBytes[i] = paddingLength;
 604     }
 605     [secretData appendBytes:paddingBytes length:paddingLength];
 606
 607     SFAuthenticatedCiphertext* ciphertext = [encryptionOperation encrypt:secretData withKey:key error:error];
 608     SecDbKeychainAKSWrappedKey* wrappedKey = [self wrapToAKS:key withKeybag:keybag accessControl:accessControl acmContext:acmContext error:error];
 609
 610     SecDbBackupWrappedItemKey* backupWrappedKey;
 611     if (checkV12DevEnabled()) {
 612         backupWrappedKey = [[SecDbBackupManager manager] wrapItemKey:key forKeyclass:_keyclass error:error];
 613         if (backupWrappedKey) {
 614             _backupUUID = backupWrappedKey.baguuid;
 615         } else {
 616             secwarning("SecDbKeychainItemV7: backup manager didn't return wrapped key: %@", error ? *error : nil);
 617             if (error) {
 618                 *error = nil;
 619             }
 620         }
 621     }
 622
 623     _encryptedSecretData = [[SecDbKeychainSecretData alloc] initWithCiphertext:ciphertext
 624                                                                     wrappedKey:wrappedKey
 625                                                                    tamperCheck:_tamperCheck
 626                                                               backupWrappedKey:backupWrappedKey
 627                                                                          error:error];
 628     return _encryptedSecretData != nil;
 629 }
 630
 631 - (SFAESKey*)metadataClassKeyWithKeybag:(keybag_handle_t)keybag
 632                      createKeyIfMissing:(bool)createIfMissing
 633                     overwriteCorruptKey:(bool)force
 634                                   error:(NSError**)error
 635 {
 636     return [[SecDbKeychainMetadataKeyStore sharedStore] keyForKeyclass:_keyclass
 637                                                                 keybag:keybag
 638                                                           keySpecifier:[self.class keySpecifier]
 639                                                     createKeyIfMissing:(bool)createIfMissing
 640                                                    overwriteCorruptKey:force
 641                                                                  error:error];
 642 }
 643
 644 - (SecDbKeychainAKSWrappedKey*)wrapToAKS:(SFAESKey*)key withKeybag:(keybag_handle_t)keybag accessControl:(SecAccessControlRef)accessControl acmContext:(NSData*)acmContext error:(NSError**)error
 645 {
 646     NSData* keyData = key.keyData;
 647
 648 #if USE_KEYSTORE
 649     NSDictionary* constraints = (__bridge NSDictionary*)SecAccessControlGetConstraints(accessControl);
 650     if (constraints) {
 651         aks_ref_key_t refKey = NULL;
 652         CFErrorRef cfError = NULL;
 653         NSData* authData = (__bridge_transfer NSData*)CFPropertyListCreateDERData(NULL, (__bridge CFDictionaryRef)@{(id)kAKSKeyAcl : constraints}, &cfError);
 654
 655         if (!acmContext || !SecAccessControlIsBound(accessControl)) {
 656             secerror("SecDbKeychainItemV7: access control error");
 657             if (error) {
 658                 CFDataRef accessControlData = SecAccessControlCopyData(accessControl);
 659                 ks_access_control_needed_error(&cfError, accessControlData, SecAccessControlIsBound(accessControl) ? kAKSKeyOpEncrypt : CFSTR(""));
 660                 CFReleaseNull(accessControlData);
 661             }
 662
 663             BridgeCFErrorToNSErrorOut(error, cfError);
 664             return nil;
 665         }
 666
 667         void* aksParams = NULL;
 668         size_t aksParamsLength = 0;
 669         aks_operation_optional_params(0, 0, authData.bytes, authData.length, acmContext.bytes, (int)acmContext.length, &aksParams, &aksParamsLength);
 670
 671         int aksResult = aks_ref_key_create(keybag, _keyclass, key_type_sym, aksParams, aksParamsLength, &refKey);
 672         if (aksResult != 0) {
 673             CFDataRef accessControlData = SecAccessControlCopyData(accessControl);
 674             create_cferror_from_aks(aksResult, kAKSKeyOpEncrypt, keybag, _keyclass, accessControlData, (__bridge CFDataRef)acmContext, &cfError);
 675             CFReleaseNull(accessControlData);
 676             free(aksParams);
 677             BridgeCFErrorToNSErrorOut(error, cfError);
 678             return nil;
 679         }
 680
 681         size_t wrappedKeySize = 0;
 682         void* wrappedKeyBytes = NULL;
 683         aksResult = aks_ref_key_encrypt(refKey, aksParams, aksParamsLength, keyData.bytes, keyData.length, &wrappedKeyBytes, &wrappedKeySize);
 684         if (aksResult != 0) {
 685             CFDataRef accessControlData = SecAccessControlCopyData(accessControl);
 686             create_cferror_from_aks(aksResult, kAKSKeyOpEncrypt, keybag, _keyclass, accessControlData, (__bridge CFDataRef)acmContext, &cfError);
 687             CFReleaseNull(accessControlData);
 688             free(aksParams);
 689             aks_ref_key_free(&refKey);
 690             BridgeCFErrorToNSErrorOut(error, cfError);
 691             return nil;
 692         }
 693         free(aksParams);
 694
 695         BridgeCFErrorToNSErrorOut(error, cfError);
 696
 697         NSData* wrappedKey = [[NSData alloc] initWithBytesNoCopy:wrappedKeyBytes length:wrappedKeySize];
 698
 699         size_t refKeyBlobLength = 0;
 700         const void* refKeyBlobBytes = aks_ref_key_get_blob(refKey, &refKeyBlobLength);
 701         NSData* refKeyBlob = [[NSData alloc] initWithBytesNoCopy:(void*)refKeyBlobBytes length:refKeyBlobLength];
 702         aks_ref_key_free(&refKey);
 703         return [[SecDbKeychainAKSWrappedKey alloc] initRefKeyWrappedKeyWithData:wrappedKey refKeyBlob:refKeyBlob];
 704     }
 705     else {
 706         NSMutableData* wrappedKey = [[NSMutableData alloc] initWithLength:(size_t)keyData.length + 40];
 707         bool success = [SecAKSObjCWrappers aksEncryptWithKeybag:keybag keyclass:_keyclass plaintext:keyData outKeyclass:&_keyclass ciphertext:wrappedKey error:error];
 708         return success ? [[SecDbKeychainAKSWrappedKey alloc] initRegularWrappedKeyWithData:wrappedKey] : nil;
 709     }
 710 #else
 711     NSMutableData* wrappedKey = [[NSMutableData alloc] initWithLength:(size_t)keyData.length + 40];
 712     bool success = [SecAKSObjCWrappers aksEncryptWithKeybag:keybag keyclass:_keyclass plaintext:keyData outKeyclass:&_keyclass ciphertext:wrappedKey error:error];
 713     return success ? [[SecDbKeychainAKSWrappedKey alloc] initRegularWrappedKeyWithData:wrappedKey] : nil;
 714 #endif
 715 }
 716
 717 - (SFAESKey*)unwrapFromAKS:(SecDbKeychainAKSWrappedKey*)wrappedKey accessControl:(SecAccessControlRef)accessControl acmContext:(NSData*)acmContext callerAccessGroups:(NSArray*)callerAccessGroups delete:(BOOL)delete error:(NSError**)error
 718 {
 719     NSData* wrappedKeyData = wrappedKey.wrappedKey;
 720
 721     if (wrappedKey.type == SecDbKeychainAKSWrappedKeyTypeRegular) {
 722         NSMutableData* unwrappedKey = [NSMutableData dataWithCapacity:wrappedKeyData.length + 40];
 723         unwrappedKey.length = wrappedKeyData.length + 40;
 724         bool result = [SecAKSObjCWrappers aksDecryptWithKeybag:_keybag keyclass:_keyclass ciphertext:wrappedKeyData outKeyclass:&_keyclass plaintext:unwrappedKey error:error];
 725         if (result) {
 726             return [[SFAESKey alloc] initWithData:unwrappedKey specifier:[self.class keySpecifier] error:error];
 727         }
 728         else {
 729             return nil;
 730         }
 731     }
 732 #if USE_KEYSTORE
 733     else if (wrappedKey.type == SecDbKeychainAKSWrappedKeyTypeRefKey) {
 734         aks_ref_key_t refKey = NULL;
 735         aks_ref_key_create_with_blob(_keybag, wrappedKey.refKeyBlob.bytes, wrappedKey.refKeyBlob.length, &refKey);
 736
 737         CFErrorRef cfError = NULL;
 738         size_t refKeyExternalDataLength = 0;
 739         const uint8_t* refKeyExternalDataBytes = aks_ref_key_get_external_data(refKey, &refKeyExternalDataLength);
 740         if (!refKeyExternalDataBytes) {
 741             aks_ref_key_free(&refKey);
 742             return nil;
 743         }
 744         NSDictionary* aclDict = nil;
 745         der_decode_plist(NULL, kCFPropertyListImmutable, (CFPropertyListRef*)(void*)&aclDict, &cfError, refKeyExternalDataBytes, refKeyExternalDataBytes + refKeyExternalDataLength);
 746         if (!aclDict) {
 747             SecError(errSecDecode, &cfError, CFSTR("SecDbKeychainItemV7: failed to decode acl dict"));
 748         }
 749         SecAccessControlSetConstraints(accessControl, (__bridge CFDictionaryRef)aclDict);
 750         if (!SecAccessControlGetConstraint(accessControl, kAKSKeyOpEncrypt)) {
 751             SecAccessControlAddConstraintForOperation(accessControl, kAKSKeyOpEncrypt, kCFBooleanTrue, &cfError);
 752         }
 753
 754         size_t derPlistLength = der_sizeof_plist((__bridge CFPropertyListRef)callerAccessGroups, &cfError);
 755         NSMutableData* accessGroupDERData = [[NSMutableData alloc] initWithLength:derPlistLength];
 756         der_encode_plist((__bridge CFPropertyListRef)callerAccessGroups, &cfError, accessGroupDERData.mutableBytes, accessGroupDERData.mutableBytes + derPlistLength);
 757         void* aksParams = NULL;
 758         size_t aksParamsLength = 0;
 759         aks_operation_optional_params(accessGroupDERData.bytes, derPlistLength, NULL, 0, acmContext.bytes, (int)acmContext.length, &aksParams, &aksParamsLength);
 760
 761         void* unwrappedKeyDERData = NULL;
 762         size_t unwrappedKeyDERLength = 0;
 763         int aksResult = aks_ref_key_decrypt(refKey, aksParams, aksParamsLength, wrappedKeyData.bytes, wrappedKeyData.length, &unwrappedKeyDERData, &unwrappedKeyDERLength);
 764         if (aksResult != 0) {
 765             CFDataRef accessControlData = SecAccessControlCopyData(accessControl);
 766             create_cferror_from_aks(aksResult, kAKSKeyOpDecrypt, 0, 0, accessControlData, (__bridge CFDataRef)acmContext, &cfError);
 767             CFReleaseNull(accessControlData);
 768             aks_ref_key_free(&refKey);
 769             free(aksParams);
 770             BridgeCFErrorToNSErrorOut(error, cfError);
 771             return nil;
 772         }
 773         if (!unwrappedKeyDERData) {
 774             SecError(errSecDecode, &cfError, CFSTR("SecDbKeychainItemV7: failed to decrypt item, Item can't be decrypted due to failed decode der, so drop the item."));
 775             aks_ref_key_free(&refKey);
 776             free(aksParams);
 777             BridgeCFErrorToNSErrorOut(error, cfError);
 778             return nil;
 779         }
 780
 781         CFPropertyListRef unwrappedKeyData = NULL;
 782         der_decode_plist(NULL, kCFPropertyListImmutable, &unwrappedKeyData, &cfError, unwrappedKeyDERData, unwrappedKeyDERData + unwrappedKeyDERLength);
 783         SFAESKey* result = nil;
 784         if ([(__bridge NSData*)unwrappedKeyData isKindOfClass:[NSData class]]) {
 785             result = [[SFAESKey alloc] initWithData:(__bridge NSData*)unwrappedKeyData specifier:[self.class keySpecifier] error:error];
 786             CFReleaseNull(unwrappedKeyDERData);
 787         }
 788         else {
 789             SecError(errSecDecode, &cfError, CFSTR("SecDbKeychainItemV7: failed to decrypt item, Item can't be decrypted due to failed decode der, so drop the item."));
 790             aks_ref_key_free(&refKey);
 791             free(aksParams);
 792             free(unwrappedKeyDERData);
 793             BridgeCFErrorToNSErrorOut(error, cfError);
 794             return nil;
 795         }
 796
 797         if (delete) {
 798             aksResult = aks_ref_key_delete(refKey, aksParams, aksParamsLength);
 799             if (aksResult != 0) {
 800                 CFDataRef accessControlData = SecAccessControlCopyData(accessControl);
 801                 create_cferror_from_aks(aksResult, kAKSKeyOpDelete, 0, 0, accessControlData, (__bridge CFDataRef)acmContext, &cfError);
 802                 CFReleaseNull(accessControlData);
 803                 aks_ref_key_free(&refKey);
 804                 free(aksParams);
 805                 free(unwrappedKeyDERData);
 806                 BridgeCFErrorToNSErrorOut(error, cfError);
 807                 return nil;
 808             }
 809         }
 810
 811         BridgeCFErrorToNSErrorOut(error, cfError);
 812         aks_ref_key_free(&refKey);
 813         free(aksParams);
 814         free(unwrappedKeyDERData);
 815         return result;
 816     }
 817 #endif
 818     else {
 819         return nil;
 820     }
 821 }
 822
 823 @end