OSX/sec/SOSCircle/SecureObjectSync/SOSBackupEvent.c

   1 /*
   2  * Copyright (c) 2015 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 /*
  25  * SOSBackupEvent.c -  Implementation of a secure object syncing peer
  26  */
  27
  28 #include <Security/SecureObjectSync/SOSBackupEvent.h>
  29 #include <corecrypto/ccsha1.h>
  30 #include <utilities/SecCFError.h>
  31 #include <utilities/SecCFRelease.h>
  32 #include <utilities/array_size.h>
  33 #include <utilities/der_plist.h>
  34 #include <utilities/der_plist_internal.h>
  35 #include <AssertMacros.h>
  36
  37 //
  38 // MARK: statics
  39 //
  40
  41 /*
  42     Event ASN.1 definitions
  43
  44 ResetEvent := SEQUENCE {
  45     keybag OCTET STRING OPTIONAL
  46 }
  47
  48 AddEvent := SET {
  49     SEQUENCE {
  50         UTF8STRING :class
  51         class UTF8STRING
  52     }
  53     SEQUENCE {
  54         UTF8STRING :hash
  55         hash OCTET STRING
  56     }
  57     SEQUENCE {
  58         UTF8STRING :data
  59         data OCTET STRING
  60     }
  61 }
  62
  63 DeleteEvent := OCTET STRING
  64
  65 CompleteEvent := INTEGER
  66
  67 Event := CHOICE {
  68     reset ResetEvent
  69     add AddEvent
  70     delete DeleteEvent
  71     complete CompleteEvent
  72 }
  73
  74  */
  75
  76 static size_t der_sizeof_backup_reset(CFDataRef keybag) {
  77     return ccder_sizeof(CCDER_CONSTRUCTED_SEQUENCE,
  78         keybag ? ccder_sizeof_raw_octet_string(CFDataGetLength(keybag)) : 0);
  79 }
  80
  81 static uint8_t* der_encode_backup_reset(CFDataRef keybag, CFErrorRef* error, const uint8_t* der, uint8_t* der_end) {
  82     return ccder_encode_constructed_tl(CCDER_CONSTRUCTED_SEQUENCE, der_end, der,
  83         keybag ? ccder_encode_raw_octet_string(CFDataGetLength(keybag), CFDataGetBytePtr(keybag), der, der_end) : der_end);
  84 }
  85
  86 static size_t der_sizeof_backup_add(CFDictionaryRef add) {
  87     return der_sizeof_dictionary(add, NULL);
  88 }
  89
  90 static uint8_t* der_encode_backup_add(CFDictionaryRef add, CFErrorRef* error, const uint8_t* der, uint8_t* der_end) {
  91     // der_dictionary tag is CCDER_CONSTRUCTED_SET
  92     return der_encode_dictionary(add, error, der, der_end);
  93 }
  94
  95 static size_t der_sizeof_backup_delete(CFDataRef deletedDigest) {
  96     return ccder_sizeof_raw_octet_string(CFDataGetLength(deletedDigest));
  97 }
  98
  99 static uint8_t* der_encode_backup_delete(CFDataRef deletedDigest, CFErrorRef* error, const uint8_t* der, uint8_t* der_end) {
 100     return ccder_encode_raw_octet_string(CFDataGetLength(deletedDigest), CFDataGetBytePtr(deletedDigest), der, der_end);
 101 }
 102
 103 static size_t der_sizeof_backup_complete(uint64_t event_num) {
 104     return ccder_sizeof_uint64(event_num);
 105 }
 106
 107 static uint8_t* der_encode_backup_complete(uint64_t event_num, CFErrorRef* error, const uint8_t* der, uint8_t* der_end) {
 108     return ccder_encode_uint64(event_num, der, der_end);
 109 }
 110
 111
 112 //
 113 // MARK: SPI
 114 //
 115
 116 static bool SOSBackupEventWrite(FILE *journalFile, CFErrorRef *error,
 117                                 size_t len,
 118                                 uint8_t *(^encode)(const uint8_t *der, uint8_t *der_end))
 119 {
 120     bool ok = false;
 121     CFMutableDataRef derObject = CFDataCreateMutable(kCFAllocatorDefault, len);
 122     CFDataSetLength(derObject, len);
 123     uint8_t *der_end = CFDataGetMutableBytePtr(derObject);
 124     const uint8_t *der = der_end;
 125     der_end += len;
 126
 127     require(der_end = encode(der, der_end), xit);
 128     require_action(der == der_end, xit, SecError(-1, error, CFSTR("size mismatch der_end - der: %td"), der_end - der));
 129
 130     ok = SecCheckErrno(1 != fwrite(der, len, 1, journalFile), error, CFSTR("fwrite SOSBackupEventWrite"));
 131 xit:
 132     CFReleaseSafe(derObject);
 133     return ok;
 134 }
 135
 136 bool SOSBackupEventWriteReset(FILE *journalFile, CFDataRef keybag, CFErrorRef *error) {
 137     return SOSBackupEventWrite(journalFile, error, der_sizeof_backup_reset(keybag), ^uint8_t *(const uint8_t *der, uint8_t *der_end) {
 138         return der_encode_backup_reset(keybag, error, der, der_end);
 139     });
 140 }
 141
 142 bool SOSBackupEventWriteDelete(FILE *journalFile, CFDataRef deletedDigest, CFErrorRef *error) {
 143     return SOSBackupEventWrite(journalFile, error, der_sizeof_backup_delete(deletedDigest), ^uint8_t *(const uint8_t *der, uint8_t *der_end) {
 144         return der_encode_backup_delete(deletedDigest, error, der, der_end);
 145     });
 146 }
 147
 148 bool SOSBackupEventWriteAdd(FILE *journalFile, CFDictionaryRef backup_item, CFErrorRef *error) {
 149     return SOSBackupEventWrite(journalFile, error, der_sizeof_backup_add(backup_item), ^uint8_t *(const uint8_t *der, uint8_t *der_end) {
 150         return der_encode_backup_add(backup_item, error, der, der_end);
 151     });
 152 }
 153
 154 bool SOSBackupEventWriteCompleteMarker(FILE *journalFile, uint64_t eventID, CFErrorRef *error) {
 155     bool ok = SOSBackupEventWrite(journalFile, error, der_sizeof_backup_complete(eventID), ^uint8_t *(const uint8_t *der, uint8_t *der_end) {
 156         return der_encode_backup_complete(eventID, error, der, der_end);
 157     });
 158     // TODO: Move this to right before we send a notification or something.
 159     fflush(journalFile);
 160     return ok;
 161 }