pexpert/gen/kcformat.c

   1 /*
   2  * Copyright (c) 2000-2020 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  * @OSF_FREE_COPYRIGHT@
  30  */
  31
  32 #include <pexpert/pexpert.h>
  33 #include <libkern/section_keywords.h>
  34 #include <libkern/kernel_mach_header.h>
  35
  36 vm_offset_t kc_highest_nonlinkedit_vmaddr = 0;
  37 int vnode_put(void *vp);
  38
  39 // FIXME: should come from mach-o/fixup_chains.h
  40 // Index in basePointers array used by chained rebase in dyld_kernel_fixups.h
  41 typedef enum kc_index {
  42         primary_kc_index = 0,
  43         pageable_kc_index = 1,
  44         auxiliary_kc_index = 3,
  45 } kc_index_t;
  46
  47 #if defined(__x86_64__) || defined(__i386__)
  48 /* FIXME: This should be locked down during early boot */
  49 void *collection_base_pointers[KCNumKinds] = {};
  50 kernel_mach_header_t * collection_mach_headers[KCNumKinds] = {};
  51 uintptr_t collection_slide[KCNumKinds] = {};
  52 void * collection_vp[KCNumKinds] = {};
  53 #else
  54
  55 SECURITY_READ_ONLY_LATE(void *) collection_base_pointers[KCNumKinds];
  56 SECURITY_READ_ONLY_LATE(kernel_mach_header_t *) collection_mach_headers[KCNumKinds];
  57 SECURITY_READ_ONLY_LATE(uintptr_t) collection_slide[KCNumKinds];
  58 SECURITY_READ_ONLY_LATE(void *) collection_vp[KCNumKinds];
  59 #endif //(__x86_64__) || defined(__i386__)
  60
  61 static inline kc_index_t
  62 kc_kind2index(kc_kind_t type)
  63 {
  64         switch (type) {
  65         case KCKindPrimary:
  66                 return primary_kc_index;
  67         case KCKindPageable:
  68                 return pageable_kc_index;
  69         case KCKindAuxiliary:
  70                 return auxiliary_kc_index;
  71         default:
  72                 panic("Invalid KC Kind");
  73                 break;
  74         }
  75         __builtin_unreachable();
  76 }
  77
  78 void
  79 PE_set_kc_header(kc_kind_t type, kernel_mach_header_t *header, uintptr_t slide)
  80 {
  81         kc_index_t i = kc_kind2index(type);
  82         assert(!collection_base_pointers[i]);
  83         assert(!collection_mach_headers[i]);
  84         collection_mach_headers[i] = header;
  85         collection_slide[i] = slide;
  86
  87         struct load_command *lc;
  88         struct segment_command_64 *seg;
  89         uint64_t lowest_vmaddr = ~0ULL;
  90
  91         lc = (struct load_command *)((uintptr_t)header + sizeof(*header));
  92         for (uint32_t j = 0; j < header->ncmds; j++,
  93             lc = (struct load_command *)((uintptr_t)lc + lc->cmdsize)) {
  94                 if (lc->cmd != LC_SEGMENT_64) {
  95                         continue;
  96                 }
  97                 seg = (struct segment_command_64 *)(uintptr_t)lc;
  98                 if (seg->vmaddr < lowest_vmaddr) {
  99                         lowest_vmaddr = seg->vmaddr;
 100                 }
 101         }
 102
 103         collection_base_pointers[i] = (void *)(uintptr_t)lowest_vmaddr + slide;
 104         assert((uint64_t)(uintptr_t)collection_base_pointers[i] != ~0ULL);
 105 }
 106
 107 void
 108 PE_reset_kc_header(kc_kind_t type)
 109 {
 110         if (type == KCKindPrimary) {
 111                 return;
 112         }
 113
 114         kc_index_t i = kc_kind2index(type);
 115         collection_mach_headers[i] = 0;
 116         collection_base_pointers[i] = 0;
 117         collection_slide[i] = 0;
 118 }
 119
 120 void
 121 PE_set_kc_header_and_base(kc_kind_t type, kernel_mach_header_t * header, void *base, uintptr_t slide)
 122 {
 123         kc_index_t i = kc_kind2index(type);
 124         assert(!collection_base_pointers[i]);
 125         assert(!collection_mach_headers[i]);
 126         collection_mach_headers[i] = header;
 127         collection_slide[i] = slide;
 128         collection_base_pointers[i] = base;
 129 }
 130
 131 void *
 132 PE_get_kc_header(kc_kind_t type)
 133 {
 134         return collection_mach_headers[kc_kind2index(type)];
 135 }
 136
 137 void
 138 PE_set_kc_vp(kc_kind_t type, void *vp)
 139 {
 140         kc_index_t i = kc_kind2index(type);
 141         assert(collection_vp[i] == NULL);
 142
 143         collection_vp[i] = vp;
 144 }
 145
 146 void *
 147 PE_get_kc_vp(kc_kind_t type)
 148 {
 149         kc_index_t i = kc_kind2index(type);
 150         return collection_vp[i];
 151 }
 152
 153 void
 154 PE_reset_all_kc_vp(void)
 155 {
 156         for (int i = 0; i < KCNumKinds; i++) {
 157                 if (collection_vp[i] != NULL) {
 158                         vnode_put(collection_vp[i]);
 159                         collection_vp[i] = NULL;
 160                 }
 161         }
 162 }
 163
 164 const void * const *
 165 PE_get_kc_base_pointers(void)
 166 {
 167         return (const void * const*)collection_base_pointers;
 168 }
 169
 170 /*
 171  * Prelinked kexts in an MH_FILESET start with address 0,
 172  * the slide for such kexts is calculated from the base
 173  * address of the first kext mapped in that KC. Return the
 174  * slide based on the type of the KC.
 175  *
 176  * Prelinked kexts booted from a non MH_FILESET KC are
 177  * marked as KCKindUnknown, for such cases, return
 178  * the kernel slide.
 179  */
 180 uintptr_t
 181 PE_get_kc_slide(kc_kind_t type)
 182 {
 183         if (type == KCKindUnknown) {
 184                 return vm_kernel_slide;
 185         }
 186         return collection_slide[kc_kind2index(type)];
 187 }
 188
 189 bool
 190 PE_get_primary_kc_format(kc_format_t *type)
 191 {
 192         if (type != NULL) {
 193                 kernel_mach_header_t *mh = PE_get_kc_header(KCKindPrimary);
 194                 if (mh && mh->filetype == MH_FILESET) {
 195                         *type = KCFormatFileset;
 196                 } else {
 197 #if defined(__arm__) || defined(__arm64__)
 198                         /* From osfmk/arm/arm_init.c */
 199                         extern bool static_kernelcache;
 200                         if (static_kernelcache) {
 201                                 *type = KCFormatStatic;
 202                         } else {
 203                                 *type = KCFormatKCGEN;
 204                         }
 205 #else
 206                         *type = KCFormatDynamic;
 207 #endif
 208                 }
 209         }
 210         return true;
 211 }
 212
 213 void *
 214 PE_get_kc_baseaddress(kc_kind_t type)
 215 {
 216         kc_index_t i = kc_kind2index(type);
 217         switch (type) {
 218 #if defined(__arm__) || defined(__arm64__)
 219         case KCKindPrimary: {
 220                 extern vm_offset_t segLOWESTTEXT;
 221                 return (void*)segLOWESTTEXT;
 222         }
 223 #endif
 224         default:
 225                 return collection_base_pointers[i];
 226         }
 227         return NULL;
 228 }