iokit/Kernel/i386/IOKeyStoreHelper.cpp

   1 /*
   2  * Copyright (c) 2010 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_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. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #include <sys/cdefs.h>
  30 #include <stdbool.h>
  31
  32 #include <IOKit/assert.h>
  33 #include <IOKit/system.h>
  34 #include <IOKit/IOLib.h>
  35 #include <IOKit/IOMemoryDescriptor.h>
  36 #include <IOKit/IOKitDebug.h>
  37
  38 __BEGIN_DECLS
  39
  40 #include <pexpert/pexpert.h>
  41
  42 static volatile UInt32 alreadyFetched = 0;
  43 static IOMemoryDescriptor * newData;
  44
  45 IOMemoryDescriptor *
  46 IOGetBootKeyStoreData(void);
  47 void
  48 IOSetKeyStoreData(IOMemoryDescriptor * data);
  49
  50 // APFS
  51 static volatile UInt32 apfsKeyFetched = 0;
  52 static IOMemoryDescriptor* apfsKeyData = NULL;
  53
  54 IOMemoryDescriptor* IOGetAPFSKeyStoreData();
  55 void IOSetAPFSKeyStoreData(IOMemoryDescriptor* data);
  56
  57 __END_DECLS
  58
  59 #if 1
  60 #define DEBG(fmt, args...)      { kprintf(fmt, ## args); }
  61 #else
  62 #define DEBG(fmt, args...)      {}
  63 #endif
  64
  65 void
  66 IOSetKeyStoreData(IOMemoryDescriptor * data)
  67 {
  68         newData = data;
  69         alreadyFetched = 0;
  70 }
  71
  72 IOMemoryDescriptor *
  73 IOGetBootKeyStoreData(void)
  74 {
  75         IOMemoryDescriptor *memoryDescriptor;
  76         boot_args *args = (boot_args *)PE_state.bootArgs;
  77         IOOptionBits options;
  78         IOAddressRange ranges;
  79
  80         if (!OSCompareAndSwap(0, 1, &alreadyFetched)) {
  81                 return NULL;
  82         }
  83
  84         if (newData) {
  85                 IOMemoryDescriptor * data = newData;
  86                 newData = NULL;
  87                 return data;
  88         }
  89
  90         DEBG("%s: data at address %u size %u\n", __func__,
  91             args->keyStoreDataStart,
  92             args->keyStoreDataSize);
  93
  94         if (args->keyStoreDataStart == 0) {
  95                 return NULL;
  96         }
  97
  98         ranges.address = args->keyStoreDataStart;
  99         ranges.length = args->keyStoreDataSize;
 100
 101         options = kIODirectionInOut | kIOMemoryTypePhysical64 | kIOMemoryMapperNone;
 102
 103         memoryDescriptor = IOMemoryDescriptor::withOptions(&ranges,
 104             1,
 105             0,
 106             NULL,
 107             options);
 108
 109         DEBG("%s: memory descriptor %p\n", __func__, memoryDescriptor);
 110
 111         return memoryDescriptor;
 112 }
 113
 114 // APFS volume key fetcher
 115
 116 // Store in-memory key (could be used by IOHibernateDone)
 117 void
 118 IOSetAPFSKeyStoreData(IOMemoryDescriptor* data)
 119 {
 120         // Do not allow re-fetching of the boot_args key by passing NULL here.
 121         if (data != NULL) {
 122                 apfsKeyData = data;
 123                 apfsKeyFetched = 0;
 124         }
 125 }
 126
 127 // Retrieve any key we may have (stored in boot_args or by Hibernate)
 128 IOMemoryDescriptor*
 129 IOGetAPFSKeyStoreData()
 130 {
 131         // Check if someone got the key before us
 132         if (!OSCompareAndSwap(0, 1, &apfsKeyFetched)) {
 133                 return NULL;
 134         }
 135
 136         // Do we have in-memory key?
 137         if (apfsKeyData) {
 138                 IOMemoryDescriptor* data = apfsKeyData;
 139                 apfsKeyData = NULL;
 140                 return data;
 141         }
 142
 143         // Looks like there was no in-memory key and it's the first call - try boot_args
 144         boot_args* args = (boot_args*)PE_state.bootArgs;
 145
 146         DEBG("%s: data at address %u size %u\n", __func__, args->apfsDataStart, args->apfsDataSize);
 147         if (args->apfsDataStart == 0) {
 148                 return NULL;
 149         }
 150
 151         // We have the key in the boot_args, create IOMemoryDescriptor for the blob
 152         IOAddressRange ranges;
 153         ranges.address = args->apfsDataStart;
 154         ranges.length = args->apfsDataSize;
 155
 156         const IOOptionBits options = kIODirectionInOut | kIOMemoryTypePhysical64 | kIOMemoryMapperNone;
 157
 158         IOMemoryDescriptor* memoryDescriptor = IOMemoryDescriptor::withOptions(&ranges, 1, 0, NULL, options);
 159         DEBG("%s: memory descriptor %p\n", __func__, memoryDescriptor);
 160         return memoryDescriptor;
 161 }