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   if (newData)
  84   {
  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   ranges.address = args->keyStoreDataStart;
  98   ranges.length = args->keyStoreDataSize;
  99
 100   options = kIODirectionInOut | kIOMemoryTypePhysical64 | kIOMemoryMapperNone;
 101
 102   memoryDescriptor = IOMemoryDescriptor::withOptions(&ranges,
 103                                                      1,
 104                                                      0,
 105                                                      NULL,
 106                                                      options);
 107
 108   DEBG("%s: memory descriptor %p\n", __func__, memoryDescriptor);
 109
 110   return memoryDescriptor;
 111 }
 112
 113 // APFS volume key fetcher
 114
 115 // Store in-memory key (could be used by IOHibernateDone)
 116 void
 117 IOSetAPFSKeyStoreData(IOMemoryDescriptor* data)
 118 {
 119     // Do not allow re-fetching of the boot_args key by passing NULL here.
 120     if (data != NULL)
 121     {
 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     // Do we have in-memory key?
 136     if (apfsKeyData)
 137     {
 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     // We have the key in the boot_args, create IOMemoryDescriptor for the blob
 151     IOAddressRange ranges;
 152     ranges.address = args->apfsDataStart;
 153     ranges.length = args->apfsDataSize;
 154
 155     const IOOptionBits options = kIODirectionInOut | kIOMemoryTypePhysical64 | kIOMemoryMapperNone;
 156
 157     IOMemoryDescriptor* memoryDescriptor = IOMemoryDescriptor::withOptions(&ranges, 1, 0, NULL, options);
 158     DEBG("%s: memory descriptor %p\n", __func__, memoryDescriptor);
 159     return memoryDescriptor;
 160 }