keychain/trust/TrustedPeers/TPPolicyDocument.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 "TPPolicyDocument.h"
  25 #import "TPPolicy.h"
  26 #import "TPUtils.h"
  27 #import "TPCategoryRule.h"
  28
  29 static const NSString *kPolicyVersion = @"policyVersion";
  30 static const NSString *kModelToCategory = @"modelToCategory";
  31 static const NSString *kCategoriesByView = @"categoriesByView";
  32 static const NSString *kIntroducersByCategory = @"introducersByCategory";
  33 static const NSString *kRedactions = @"redactions";
  34 static const NSString *kPrefix = @"prefix";
  35 static const NSString *kCategory = @"category";
  36
  37 @interface TPPolicyDocument ()
  38
  39 @property (nonatomic, assign) TPCounter policyVersion;
  40 @property (nonatomic, strong) NSString *policyHash;
  41 @property (nonatomic, strong) NSData *pList;
  42
  43 @property (nonatomic, strong) NSArray<TPCategoryRule*> *modelToCategory;
  44 @property (nonatomic, strong) NSDictionary<NSString*,NSSet<NSString*>*> *categoriesByView;
  45 @property (nonatomic, strong) NSDictionary<NSString*,NSSet<NSString*>*> *introducersByCategory;
  46 @property (nonatomic, strong) NSDictionary<NSString*,NSData*> *redactions;
  47
  48 @end
  49
  50
  51 @implementation TPPolicyDocument
  52
  53 + (nullable NSArray<TPCategoryRule*> *)modelToCategoryFromObj:(id)obj
  54 {
  55     if (![obj isKindOfClass:[NSArray class]]) {
  56         return nil;
  57     }
  58     NSArray *arr = obj;
  59     NSMutableArray<TPCategoryRule*> *rules = [[NSMutableArray alloc] initWithCapacity:arr.count];
  60     for (id item in arr) {
  61         TPCategoryRule *rule = [self categoryRuleFromObj:item];
  62         if (nil == rule) {
  63             return nil;
  64         }
  65         [rules addObject:rule];
  66     }
  67     return rules;
  68 }
  69
  70 + (nullable TPCategoryRule *)categoryRuleFromObj:(id)obj
  71 {
  72     if (![obj isKindOfClass:[NSDictionary class]]) {
  73         return nil;
  74     }
  75     NSDictionary *dict = obj;
  76     if (![dict[kPrefix] isKindOfClass:[NSString class]]) {
  77         return nil;
  78     }
  79     if (![dict[kCategory] isKindOfClass:[NSString class]]) {
  80         return nil;
  81     }
  82     return [TPCategoryRule ruleWithPrefix:dict[kPrefix] category:dict[kCategory]];
  83 }
  84
  85 // Used for parsing categoriesByView and introducersByCategory
  86 // which both have the same structure.
  87 + (nullable NSDictionary<NSString*,NSSet<NSString*>*> *)dictionaryOfSetsFromObj:(id)obj
  88 {
  89     if (![obj isKindOfClass:[NSDictionary class]]) {
  90         return nil;
  91     }
  92     NSDictionary *dict = obj;
  93     NSMutableDictionary<NSString*,NSSet<NSString*>*> *result = [NSMutableDictionary dictionary];
  94     for (id key in dict) {
  95         if (![key isKindOfClass:[NSString class]]) {
  96             return nil;
  97         }
  98         id value = dict[key];
  99         if (![value isKindOfClass:[NSArray class]]) {
 100             return nil;
 101         }
 102         NSArray *arr = value;
 103         for (id item in arr) {
 104             if (![item isKindOfClass:[NSString class]]) {
 105                 return nil;
 106             }
 107         }
 108         result[key] = [NSSet setWithArray:arr];
 109     }
 110     return result;
 111 }
 112
 113 + (nullable NSDictionary<NSString*,NSData*> *)redactionsFromObj:(id)obj
 114 {
 115     if (![obj isKindOfClass:[NSDictionary class]]) {
 116         return nil;
 117     }
 118     NSDictionary *dict = obj;
 119     for (id key in dict) {
 120         if (![key isKindOfClass:[NSString class]]) {
 121             return nil;
 122         }
 123         id value = dict[key];
 124         if (![value isKindOfClass:[NSData class]]) {
 125             return nil;
 126         }
 127     }
 128     return dict;
 129 }
 130
 131 + (nullable instancetype)policyDocWithHash:(NSString *)policyHash
 132                                      pList:(NSData *)pList
 133 {
 134     TPHashAlgo algo = [TPHashBuilder algoOfHash:policyHash];
 135     NSString *hash = [TPHashBuilder hashWithAlgo:algo ofData:pList];
 136     if (![policyHash isEqualToString:hash]) {
 137         return nil;
 138     }
 139     TPPolicyDocument *doc = [[TPPolicyDocument alloc] init];
 140     doc.policyHash = hash;
 141     doc.pList = pList;
 142
 143     id obj = [NSPropertyListSerialization propertyListWithData:pList
 144                                                         options:NSPropertyListImmutable
 145                                                          format:nil
 146                                                           error:NULL];
 147     if (![obj isKindOfClass:[NSDictionary class]]) {
 148         return nil;
 149     }
 150     NSDictionary *dict = obj;
 151
 152     if (![dict[kPolicyVersion] isKindOfClass:[NSNumber class]]) {
 153         return nil;
 154     }
 155     doc.policyVersion = [dict[kPolicyVersion] unsignedLongLongValue];
 156
 157     doc.modelToCategory = [self modelToCategoryFromObj:dict[kModelToCategory]];
 158     if (nil == doc.modelToCategory) {
 159         return nil;
 160     }
 161     doc.categoriesByView = [self dictionaryOfSetsFromObj:dict[kCategoriesByView]];
 162     if (nil == doc.categoriesByView) {
 163         return nil;
 164     }
 165     doc.introducersByCategory = [self dictionaryOfSetsFromObj:dict[kIntroducersByCategory]];
 166     if (nil == doc.introducersByCategory) {
 167         return nil;
 168     }
 169     doc.redactions = [self redactionsFromObj:dict[kRedactions]];
 170     if (nil == doc.redactions) {
 171         return nil;
 172     }
 173     return doc;
 174 }
 175
 176 + (instancetype)policyDocWithVersion:(TPCounter)policyVersion
 177                      modelToCategory:(NSArray<NSDictionary*> *)modelToCategory
 178                     categoriesByView:(NSDictionary<NSString*,NSArray<NSString*>*> *)categoriesByView
 179                introducersByCategory:(NSDictionary<NSString*,NSArray<NSString*>*> *)introducersByCategory
 180                           redactions:(NSDictionary<NSString*,NSData*> *)redactions
 181                             hashAlgo:(TPHashAlgo)hashAlgo
 182 {
 183     TPPolicyDocument *doc = [[TPPolicyDocument alloc] init];
 184
 185     doc.policyVersion = policyVersion;
 186
 187     doc.modelToCategory = [TPPolicyDocument modelToCategoryFromObj:modelToCategory];
 188     NSAssert(doc.modelToCategory, @"malformed modelToCategory");
 189
 190     doc.categoriesByView = [TPPolicyDocument dictionaryOfSetsFromObj:categoriesByView];
 191     NSAssert(doc.categoriesByView, @"malformed categoriesByView");
 192
 193     doc.introducersByCategory = [TPPolicyDocument dictionaryOfSetsFromObj:introducersByCategory];
 194     NSAssert(doc.introducersByCategory, @"malformed introducersByCategory");
 195
 196     doc.redactions = [redactions copy];
 197
 198     NSDictionary *dict = @{
 199                            kPolicyVersion: @(policyVersion),
 200                            kModelToCategory: modelToCategory,
 201                            kCategoriesByView: categoriesByView,
 202                            kIntroducersByCategory: introducersByCategory,
 203                            kRedactions: redactions
 204                            };
 205     doc.pList = [TPUtils serializedPListWithDictionary:dict];
 206     doc.policyHash = [TPHashBuilder hashWithAlgo:hashAlgo ofData:doc.pList];
 207
 208     return doc;
 209 }
 210
 211 + (nullable NSData *)redactionWithEncrypter:(id<TPEncrypter>)encrypter
 212                             modelToCategory:(nullable NSArray<NSDictionary*> *)modelToCategory
 213                            categoriesByView:(nullable NSDictionary<NSString*,NSArray<NSString*>*> *)categoriesByView
 214                       introducersByCategory:(nullable NSDictionary<NSString*,NSArray<NSString*>*> *)introducersByCategory
 215                                       error:(NSError **)error
 216 {
 217     NSMutableDictionary *dict = [NSMutableDictionary dictionary];
 218     if (nil != modelToCategory) {
 219         dict[kModelToCategory] = modelToCategory;
 220     }
 221     if (nil != categoriesByView) {
 222         dict[kCategoriesByView] = categoriesByView;
 223     }
 224     if (nil != introducersByCategory) {
 225         dict[kIntroducersByCategory] = introducersByCategory;
 226     }
 227     NSData *plist = [TPUtils serializedPListWithDictionary:dict];
 228     return [encrypter encryptData:plist error:error];
 229 }
 230
 231 - (id<TPPolicy>)policyWithSecrets:(NSDictionary<NSString*,NSData*> *)secrets
 232                         decrypter:(id<TPDecrypter>)decrypter
 233                             error:(NSError **)error
 234 {
 235     NSArray<TPCategoryRule*> *modelToCategory = self.modelToCategory;
 236     NSMutableDictionary<NSString*,NSSet<NSString*>*> *categoriesByView
 237         = [NSMutableDictionary dictionaryWithDictionary:self.categoriesByView];
 238     NSMutableDictionary<NSString*,NSSet<NSString*>*> *introducersByCategory
 239         = [NSMutableDictionary dictionaryWithDictionary:self.introducersByCategory];
 240
 241     // We are going to prepend extra items to modelToCategory.
 242     // To make the resulting array order deterministic we sort secrets by name first.
 243     NSArray<NSString*> *names = [secrets.allKeys sortedArrayUsingSelector:@selector(compare:)];
 244     for (NSString *name in names) {
 245         NSData *key = secrets[name];
 246         NSData *ciphertext = self.redactions[name];
 247         if (nil == ciphertext) {
 248             // This is normal. A new version might have no need to redact
 249             // info that was revealed by keys for a previous version.
 250             continue;
 251         }
 252         NSData *plist = [decrypter decryptData:ciphertext withKey:key error:error];
 253         if (nil == plist) {
 254             return nil;
 255         }
 256         id obj = [NSPropertyListSerialization propertyListWithData:plist
 257                                                            options:NSPropertyListImmutable
 258                                                             format:nil
 259                                                              error:NULL];
 260         if (![obj isKindOfClass:[NSDictionary class]]) {
 261             return nil;
 262         }
 263         NSDictionary *dict = obj;
 264
 265         NSArray<TPCategoryRule*> *extraModelToCategory;
 266         extraModelToCategory = [TPPolicyDocument modelToCategoryFromObj:dict[kModelToCategory]];
 267         if (nil != extraModelToCategory) {
 268             // Extra rules are prepended to the list so that they are considered first.
 269             modelToCategory = [extraModelToCategory arrayByAddingObjectsFromArray:modelToCategory];
 270         }
 271
 272         NSDictionary<NSString*,NSSet<NSString*>*> *extraCategoriesByView;
 273         extraCategoriesByView = [TPPolicyDocument dictionaryOfSetsFromObj:dict[kCategoriesByView]];
 274         if (nil != extraCategoriesByView) {
 275             [self mergeExtras:extraCategoriesByView intoDictionary:categoriesByView];
 276         }
 277
 278         NSDictionary<NSString*,NSSet<NSString*>*> *extraIntroducersByCategory;
 279         extraIntroducersByCategory = [TPPolicyDocument dictionaryOfSetsFromObj:dict[kIntroducersByCategory]];
 280         if (nil != extraIntroducersByCategory) {
 281             [self mergeExtras:extraIntroducersByCategory intoDictionary:introducersByCategory];
 282         }
 283     }
 284
 285     return [TPPolicy policyWithModelToCategory:modelToCategory
 286                               categoriesByView:categoriesByView
 287                          introducersByCategory:introducersByCategory];
 288 }
 289
 290 - (void)mergeExtras:(NSDictionary<NSString*,NSSet<NSString*>*> *)extras
 291      intoDictionary:(NSMutableDictionary<NSString*,NSSet<NSString*>*> *)target
 292 {
 293     for (NSString *name in extras) {
 294         NSSet<NSString*>* extraSet = extras[name];
 295         if (target[name] == nil) {
 296             target[name] = extraSet;
 297         } else {
 298             target[name] = [target[name] setByAddingObjectsFromSet:extraSet];
 299         }
 300     }
 301 }
 302
 303 - (BOOL)isEqualToPolicyDocument:(TPPolicyDocument *)other
 304 {
 305     if (other == self) {
 306         return YES;
 307     }
 308     return self.policyVersion == other.policyVersion
 309         && [self.policyHash isEqualToString:other.policyHash]
 310         && [self.pList isEqualToData:other.pList]
 311         && [self.modelToCategory isEqualToArray:other.modelToCategory]
 312         && [self.categoriesByView isEqualToDictionary:other.categoriesByView]
 313         && [self.introducersByCategory isEqualToDictionary:other.introducersByCategory]
 314         && [self.redactions isEqualToDictionary:other.redactions];
 315 }
 316
 317 #pragma mark - NSObject
 318
 319 - (BOOL)isEqual:(id)object
 320 {
 321     if (self == object) {
 322         return YES;
 323     }
 324     if (![object isKindOfClass:[TPPolicyDocument class]]) {
 325         return NO;
 326     }
 327     return [self isEqualToPolicyDocument:object];
 328 }
 329
 330 - (NSUInteger)hash
 331 {
 332     return [self.policyHash hash];
 333 }
 334
 335 @end