keychain/ot/OTBottledPeer.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 "OTBottledPeer.h"
  25
  26 #if OCTAGON
  27 #import <SecurityFoundation/SFEncryptionOperation.h>
  28 #import <SecurityFoundation/SFSigningOperation.h>
  29 #import <SecurityFoundation/SFDigestOperation.h>
  30 #import <SecurityFoundation/SFKey.h>
  31 #import <SecurityFoundation/SFKey_Private.h>
  32
  33 #import <Security/SecKeyPriv.h>
  34
  35 #import <corecrypto/cchkdf.h>
  36 #import <corecrypto/ccsha2.h>
  37 #import <corecrypto/ccec.h>
  38
  39 #import <utilities/debugging.h>
  40
  41 #import <CommonCrypto/CommonRandomSPI.h>
  42
  43 #import "OTBottle.h"
  44 #import "OTBottleContents.h"
  45 #import "OTDefines.h"
  46 #import "OTPrivateKey.h"
  47 #import "OTPrivateKey+SF.h"
  48 #import "OTAuthenticatedCiphertext.h"
  49 #import "OTAuthenticatedCiphertext+SF.h"
  50 #import "SFPublicKey+SPKI.h"
  51
  52 @interface OTBottledPeer ()
  53
  54 @property (nonatomic, strong) NSString* peerID;
  55 @property (nonatomic, strong) NSString* spID;
  56 @property (nonatomic, strong) SFECKeyPair* peerSigningKey;
  57 @property (nonatomic, strong) SFECKeyPair* peerEncryptionKey;
  58 @property (nonatomic, strong) NSData* data;
  59
  60 @end
  61
  62 @implementation OTBottledPeer
  63
  64 + (SFAuthenticatedEncryptionOperation *) encryptionOperation
  65 {
  66     SFAESKeySpecifier *keySpecifier = [[SFAESKeySpecifier alloc] initWithBitSize:SFAESKeyBitSize256];
  67     return [[SFAuthenticatedEncryptionOperation alloc] initWithKeySpecifier:keySpecifier];
  68 }
  69
  70 // Given a peer's details including private key material, and
  71 // the keys generated from the escrow secret, encrypt the peer private keys,
  72 // make a bottled peer object and serialize it into data.
  73 - (nullable instancetype) initWithPeerID:(NSString * _Nullable)peerID
  74                                     spID:(NSString * _Nullable)spID
  75                           peerSigningKey:(SFECKeyPair *)peerSigningKey
  76                        peerEncryptionKey:(SFECKeyPair *)peerEncryptionKey
  77                               escrowKeys:(OTEscrowKeys *)escrowKeys
  78                                    error:(NSError**)error
  79 {
  80     self = [super init];
  81     if (self) {
  82         // Serialize the peer private keys into "contents"
  83         OTBottleContents *contentsObj = [[OTBottleContents alloc] init];
  84         contentsObj.peerSigningPrivKey = [OTPrivateKey fromECKeyPair:peerSigningKey];
  85         contentsObj.peerEncryptionPrivKey = [OTPrivateKey fromECKeyPair:peerEncryptionKey];
  86         NSData *clearContentsData = contentsObj.data;
  87
  88         // Encrypt the contents
  89         SFAuthenticatedEncryptionOperation *op = [OTBottledPeer encryptionOperation];
  90         SFAuthenticatedCiphertext* cipher = [op encrypt:clearContentsData withKey:escrowKeys.symmetricKey error:error];
  91         if (!cipher) {
  92             return nil;
  93         }
  94
  95         // Serialize the whole thing
  96         OTBottle *obj = [[OTBottle alloc] init];
  97         obj.peerID = peerID;
  98         obj.spID = spID;
  99         obj.escrowedSigningSPKI    = [escrowKeys.signingKey.publicKey asSPKI];
 100         obj.escrowedEncryptionSPKI = [escrowKeys.encryptionKey.publicKey asSPKI];
 101         obj.peerSigningSPKI        = [peerSigningKey.publicKey asSPKI];
 102         obj.peerEncryptionSPKI     = [peerEncryptionKey.publicKey asSPKI];
 103         obj.contents = [OTAuthenticatedCiphertext fromSFAuthenticatedCiphertext:cipher];
 104
 105         _peerID = [peerID copy];
 106         _spID = [spID copy];
 107         _peerSigningKey = peerSigningKey;
 108         _peerEncryptionKey = peerEncryptionKey;
 109         _data = obj.data;
 110     }
 111     return self;
 112 }
 113
 114 // Deserialize a bottle and decrypt the contents (peer keys)
 115 // using the keys generated from the escrow secret.
 116 - (nullable instancetype) initWithData:(NSData *)data
 117                             escrowKeys:(OTEscrowKeys *)escrowKeys
 118                                  error:(NSError**)error
 119 {
 120     self = [super init];
 121     if (self) {
 122         NSError* localError =nil;
 123
 124         // Deserialize the whole thing
 125         OTBottle *obj = [[OTBottle alloc] initWithData:data];
 126         if (!obj) {
 127             secerror("octagon: failed to deserialize data into OTBottle");
 128             if(error){
 129                 *error = [NSError errorWithDomain:octagonErrorDomain code:OTErrorDeserializationFailure userInfo:@{NSLocalizedDescriptionKey: @"Failed to deserialize bottle peer"}];
 130             }
 131             return nil;
 132         }
 133
 134         // Decrypt contents
 135         SFAuthenticatedEncryptionOperation *op = [OTBottledPeer encryptionOperation];
 136         SFAuthenticatedCiphertext* ciphertext = [obj.contents asSFAuthenticatedCiphertext];
 137         NSData* clearContentsData = [op decrypt:ciphertext withKey:escrowKeys.symmetricKey error:&localError];
 138         if (!clearContentsData || clearContentsData.length == 0) {
 139             secerror("octagon: could not decrypt bottle contents: %@", localError);
 140             if(error){
 141                 *error = localError;
 142             }
 143             return nil;
 144         }
 145
 146         // Deserialize contents into private peer keys
 147         OTBottleContents *contentsObj = [[OTBottleContents alloc] initWithData:clearContentsData];
 148         if (!contentsObj) {
 149             secerror("octagon: could not deserialize bottle contents");
 150             if(error){
 151                 *error = [NSError errorWithDomain:octagonErrorDomain code:OTErrorDeserializationFailure userInfo:@{NSLocalizedDescriptionKey: @"Failed to deserialize bottle contents"}];
 152             }
 153             return nil;
 154         }
 155
 156         _peerID = obj.peerID;
 157         _spID = obj.spID;
 158         _peerSigningKey    = [contentsObj.peerSigningPrivKey asECKeyPair];
 159         _peerEncryptionKey = [contentsObj.peerEncryptionPrivKey asECKeyPair];
 160         if (!_peerSigningKey || !_peerEncryptionKey) {
 161             secerror("octagon: could not get private EC keys from bottle contents");
 162             if(error){
 163                 *error = [NSError errorWithDomain:octagonErrorDomain code:OTErrorPrivateKeyFailure userInfo:@{NSLocalizedDescriptionKey: @"Failed to instantiate octagon peer keys"}];
 164             }
 165             return nil;
 166         }
 167         _data = [data copy];
 168
 169         SFECPublicKey *peerSigningPubKey = [SFECPublicKey fromSPKI:obj.peerSigningSPKI];
 170         SFECPublicKey *peerEncryptionPubKey = [SFECPublicKey fromSPKI:obj.peerEncryptionSPKI];
 171
 172         // Check the private keys match the public keys
 173         if (![_peerSigningKey.publicKey isEqual:peerSigningPubKey]) {
 174             secerror("octagon: public and private peer signing keys do not match");
 175             if(error){
 176                 *error = [NSError errorWithDomain:octagonErrorDomain code:OTErrorPrivateKeyFailure userInfo:@{NSLocalizedDescriptionKey: @"public and private peer signing keys do not match"}];
 177             }
 178             return nil;
 179         }
 180         if (![_peerEncryptionKey.publicKey isEqual:peerEncryptionPubKey]) {
 181             secerror("octagon: public and private peer encryption keys do not match");
 182             if(error){
 183                 *error = [NSError errorWithDomain:octagonErrorDomain code:OTErrorPrivateKeyFailure userInfo:@{NSLocalizedDescriptionKey: @"public and private peer encryption keys do not match"}];
 184             }
 185             return nil;
 186         }
 187
 188     }
 189     return self;
 190 }
 191
 192 @end
 193
 194 #endif
 195
 196