lib/efi_loader/efi_image_loader.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *  EFI image loader
   4  *
   5  *  based partly on wine code
   6  *
   7  *  Copyright (c) 2016 Alexander Graf
   8  */
   9
  10 #define LOG_CATEGORY LOGC_EFI
  11
  12 #include <common.h>
  13 #include <cpu_func.h>
  14 #include <efi_loader.h>
  15 #include <log.h>
  16 #include <malloc.h>
  17 #include <pe.h>
  18 #include <sort.h>
  19 #include <crypto/mscode.h>
  20 #include <crypto/pkcs7_parser.h>
  21 #include <linux/err.h>
  22
  23 const efi_guid_t efi_global_variable_guid = EFI_GLOBAL_VARIABLE_GUID;
  24 const efi_guid_t efi_guid_device_path = EFI_DEVICE_PATH_PROTOCOL_GUID;
  25 const efi_guid_t efi_guid_loaded_image = EFI_LOADED_IMAGE_PROTOCOL_GUID;
  26 const efi_guid_t efi_guid_loaded_image_device_path =
  27                 EFI_LOADED_IMAGE_DEVICE_PATH_PROTOCOL_GUID;
  28 const efi_guid_t efi_simple_file_system_protocol_guid =
  29                 EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
  30 const efi_guid_t efi_file_info_guid = EFI_FILE_INFO_GUID;
  31
  32 static int machines[] = {
  33 #if defined(__aarch64__)
  34         IMAGE_FILE_MACHINE_ARM64,
  35 #elif defined(__arm__)
  36         IMAGE_FILE_MACHINE_ARM,
  37         IMAGE_FILE_MACHINE_THUMB,
  38         IMAGE_FILE_MACHINE_ARMNT,
  39 #endif
  40
  41 #if defined(__x86_64__)
  42         IMAGE_FILE_MACHINE_AMD64,
  43 #elif defined(__i386__)
  44         IMAGE_FILE_MACHINE_I386,
  45 #endif
  46
  47 #if defined(__riscv) && (__riscv_xlen == 32)
  48         IMAGE_FILE_MACHINE_RISCV32,
  49 #endif
  50
  51 #if defined(__riscv) && (__riscv_xlen == 64)
  52         IMAGE_FILE_MACHINE_RISCV64,
  53 #endif
  54         0 };
  55
  56 /**
  57  * efi_print_image_info() - print information about a loaded image
  58  *
  59  * If the program counter is located within the image the offset to the base
  60  * address is shown.
  61  *
  62  * @obj:        EFI object
  63  * @image:      loaded image
  64  * @pc:         program counter (use NULL to suppress offset output)
  65  * Return:      status code
  66  */
  67 static efi_status_t efi_print_image_info(struct efi_loaded_image_obj *obj,
  68                                          struct efi_loaded_image *image,
  69                                          void *pc)
  70 {
  71         printf("UEFI image");
  72         printf(" [0x%p:0x%p]",
  73                image->image_base, image->image_base + image->image_size - 1);
  74         if (pc && pc >= image->image_base &&
  75             pc < image->image_base + image->image_size)
  76                 printf(" pc=0x%zx", pc - image->image_base);
  77         if (image->file_path)
  78                 printf(" '%pD'", image->file_path);
  79         printf("\n");
  80         return EFI_SUCCESS;
  81 }
  82
  83 /**
  84  * efi_print_image_infos() - print information about all loaded images
  85  *
  86  * @pc:         program counter (use NULL to suppress offset output)
  87  */
  88 void efi_print_image_infos(void *pc)
  89 {
  90         struct efi_object *efiobj;
  91         struct efi_handler *handler;
  92
  93         list_for_each_entry(efiobj, &efi_obj_list, link) {
  94                 list_for_each_entry(handler, &efiobj->protocols, link) {
  95                         if (!guidcmp(&handler->guid, &efi_guid_loaded_image)) {
  96                                 efi_print_image_info(
  97                                         (struct efi_loaded_image_obj *)efiobj,
  98                                         handler->protocol_interface, pc);
  99                         }
 100                 }
 101         }
 102 }
 103
 104 /**
 105  * efi_loader_relocate() - relocate UEFI binary
 106  *
 107  * @rel:                pointer to the relocation table
 108  * @rel_size:           size of the relocation table in bytes
 109  * @efi_reloc:          actual load address of the image
 110  * @pref_address:       preferred load address of the image
 111  * Return:              status code
 112  */
 113 static efi_status_t efi_loader_relocate(const IMAGE_BASE_RELOCATION *rel,
 114                         unsigned long rel_size, void *efi_reloc,
 115                         unsigned long pref_address)
 116 {
 117         unsigned long delta = (unsigned long)efi_reloc - pref_address;
 118         const IMAGE_BASE_RELOCATION *end;
 119         int i;
 120
 121         if (delta == 0)
 122                 return EFI_SUCCESS;
 123
 124         end = (const IMAGE_BASE_RELOCATION *)((const char *)rel + rel_size);
 125         while (rel < end && rel->SizeOfBlock) {
 126                 const uint16_t *relocs = (const uint16_t *)(rel + 1);
 127                 i = (rel->SizeOfBlock - sizeof(*rel)) / sizeof(uint16_t);
 128                 while (i--) {
 129                         uint32_t offset = (uint32_t)(*relocs & 0xfff) +
 130                                           rel->VirtualAddress;
 131                         int type = *relocs >> EFI_PAGE_SHIFT;
 132                         uint64_t *x64 = efi_reloc + offset;
 133                         uint32_t *x32 = efi_reloc + offset;
 134                         uint16_t *x16 = efi_reloc + offset;
 135
 136                         switch (type) {
 137                         case IMAGE_REL_BASED_ABSOLUTE:
 138                                 break;
 139                         case IMAGE_REL_BASED_HIGH:
 140                                 *x16 += ((uint32_t)delta) >> 16;
 141                                 break;
 142                         case IMAGE_REL_BASED_LOW:
 143                                 *x16 += (uint16_t)delta;
 144                                 break;
 145                         case IMAGE_REL_BASED_HIGHLOW:
 146                                 *x32 += (uint32_t)delta;
 147                                 break;
 148                         case IMAGE_REL_BASED_DIR64:
 149                                 *x64 += (uint64_t)delta;
 150                                 break;
 151 #ifdef __riscv
 152                         case IMAGE_REL_BASED_RISCV_HI20:
 153                                 *x32 = ((*x32 & 0xfffff000) + (uint32_t)delta) |
 154                                         (*x32 & 0x00000fff);
 155                                 break;
 156                         case IMAGE_REL_BASED_RISCV_LOW12I:
 157                         case IMAGE_REL_BASED_RISCV_LOW12S:
 158                                 /* We know that we're 4k aligned */
 159                                 if (delta & 0xfff) {
 160                                         log_err("Unsupported reloc offset\n");
 161                                         return EFI_LOAD_ERROR;
 162                                 }
 163                                 break;
 164 #endif
 165                         default:
 166                                 log_err("Unknown Relocation off %x type %x\n",
 167                                         offset, type);
 168                                 return EFI_LOAD_ERROR;
 169                         }
 170                         relocs++;
 171                 }
 172                 rel = (const IMAGE_BASE_RELOCATION *)relocs;
 173         }
 174         return EFI_SUCCESS;
 175 }
 176
 177 void __weak invalidate_icache_all(void)
 178 {
 179         /* If the system doesn't support icache_all flush, cross our fingers */
 180 }
 181
 182 /**
 183  * efi_set_code_and_data_type() - determine the memory types to be used for code
 184  *                                and data.
 185  *
 186  * @loaded_image_info:  image descriptor
 187  * @image_type:         field Subsystem of the optional header for
 188  *                      Windows specific field
 189  */
 190 static void efi_set_code_and_data_type(
 191                         struct efi_loaded_image *loaded_image_info,
 192                         uint16_t image_type)
 193 {
 194         switch (image_type) {
 195         case IMAGE_SUBSYSTEM_EFI_APPLICATION:
 196                 loaded_image_info->image_code_type = EFI_LOADER_CODE;
 197                 loaded_image_info->image_data_type = EFI_LOADER_DATA;
 198                 break;
 199         case IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER:
 200                 loaded_image_info->image_code_type = EFI_BOOT_SERVICES_CODE;
 201                 loaded_image_info->image_data_type = EFI_BOOT_SERVICES_DATA;
 202                 break;
 203         case IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER:
 204         case IMAGE_SUBSYSTEM_EFI_ROM:
 205                 loaded_image_info->image_code_type = EFI_RUNTIME_SERVICES_CODE;
 206                 loaded_image_info->image_data_type = EFI_RUNTIME_SERVICES_DATA;
 207                 break;
 208         default:
 209                 log_err("invalid image type: %u\n", image_type);
 210                 /* Let's assume it is an application */
 211                 loaded_image_info->image_code_type = EFI_LOADER_CODE;
 212                 loaded_image_info->image_data_type = EFI_LOADER_DATA;
 213                 break;
 214         }
 215 }
 216
 217 /**
 218  * efi_image_region_add() - add an entry of region
 219  * @regs:       Pointer to array of regions
 220  * @start:      Start address of region (included)
 221  * @end:        End address of region (excluded)
 222  * @nocheck:    flag against overlapped regions
 223  *
 224  * Take one entry of region \[@start, @end\[ and insert it into the list.
 225  *
 226  * * If @nocheck is false, the list will be sorted ascending by address.
 227  *   Overlapping entries will not be allowed.
 228  *
 229  * * If @nocheck is true, the list will be sorted ascending by sequence
 230  *   of adding the entries. Overlapping is allowed.
 231  *
 232  * Return:      status code
 233  */
 234 efi_status_t efi_image_region_add(struct efi_image_regions *regs,
 235                                   const void *start, const void *end,
 236                                   int nocheck)
 237 {
 238         struct image_region *reg;
 239         int i, j;
 240
 241         if (regs->num >= regs->max) {
 242                 log_err("%s: no more room for regions\n", __func__);
 243                 return EFI_OUT_OF_RESOURCES;
 244         }
 245
 246         if (end < start)
 247                 return EFI_INVALID_PARAMETER;
 248
 249         for (i = 0; i < regs->num; i++) {
 250                 reg = &regs->reg[i];
 251                 if (nocheck)
 252                         continue;
 253
 254                 /* new data after registered region */
 255                 if (start >= reg->data + reg->size)
 256                         continue;
 257
 258                 /* new data preceding registered region */
 259                 if (end <= reg->data) {
 260                         for (j = regs->num - 1; j >= i; j--)
 261                                 memcpy(&regs->reg[j + 1], &regs->reg[j],
 262                                        sizeof(*reg));
 263                         break;
 264                 }
 265
 266                 /* new data overlapping registered region */
 267                 log_err("%s: new region already part of another\n", __func__);
 268                 return EFI_INVALID_PARAMETER;
 269         }
 270
 271         reg = &regs->reg[i];
 272         reg->data = start;
 273         reg->size = end - start;
 274         regs->num++;
 275
 276         return EFI_SUCCESS;
 277 }
 278
 279 /**
 280  * cmp_pe_section() - compare virtual addresses of two PE image sections
 281  * @arg1:       pointer to pointer to first section header
 282  * @arg2:       pointer to pointer to second section header
 283  *
 284  * Compare the virtual addresses of two sections of an portable executable.
 285  * The arguments are defined as const void * to allow usage with qsort().
 286  *
 287  * Return:      -1 if the virtual address of arg1 is less than that of arg2,
 288  *              0 if the virtual addresses are equal, 1 if the virtual address
 289  *              of arg1 is greater than that of arg2.
 290  */
 291 static int cmp_pe_section(const void *arg1, const void *arg2)
 292 {
 293         const IMAGE_SECTION_HEADER *section1, *section2;
 294
 295         section1 = *((const IMAGE_SECTION_HEADER **)arg1);
 296         section2 = *((const IMAGE_SECTION_HEADER **)arg2);
 297
 298         if (section1->VirtualAddress < section2->VirtualAddress)
 299                 return -1;
 300         else if (section1->VirtualAddress == section2->VirtualAddress)
 301                 return 0;
 302         else
 303                 return 1;
 304 }
 305
 306 /**
 307  * efi_prepare_aligned_image() - prepare 8-byte aligned image
 308  * @efi:                pointer to the EFI binary
 309  * @efi_size:           size of @efi binary
 310  *
 311  * If @efi is not 8-byte aligned, this function newly allocates
 312  * the image buffer.
 313  *
 314  * Return:      valid pointer to a image, return NULL if allocation fails.
 315  */
 316 void *efi_prepare_aligned_image(void *efi, u64 *efi_size)
 317 {
 318         size_t new_efi_size;
 319         void *new_efi;
 320
 321         /*
 322          * Size must be 8-byte aligned and the trailing bytes must be
 323          * zero'ed. Otherwise hash value may be incorrect.
 324          */
 325         if (!IS_ALIGNED(*efi_size, 8)) {
 326                 new_efi_size = ALIGN(*efi_size, 8);
 327                 new_efi = calloc(new_efi_size, 1);
 328                 if (!new_efi)
 329                         return NULL;
 330                 memcpy(new_efi, efi, *efi_size);
 331                 *efi_size = new_efi_size;
 332                 return new_efi;
 333         } else {
 334                 return efi;
 335         }
 336 }
 337
 338 /**
 339  * efi_image_parse() - parse a PE image
 340  * @efi:        Pointer to image
 341  * @len:        Size of @efi
 342  * @regp:       Pointer to a list of regions
 343  * @auth:       Pointer to a pointer to authentication data in PE
 344  * @auth_len:   Size of @auth
 345  *
 346  * Parse image binary in PE32(+) format, assuming that sanity of PE image
 347  * has been checked by a caller.
 348  * On success, an address of authentication data in @efi and its size will
 349  * be returned in @auth and @auth_len, respectively.
 350  *
 351  * Return:      true on success, false on error
 352  */
 353 bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,
 354                      WIN_CERTIFICATE **auth, size_t *auth_len)
 355 {
 356         struct efi_image_regions *regs;
 357         IMAGE_DOS_HEADER *dos;
 358         IMAGE_NT_HEADERS32 *nt;
 359         IMAGE_SECTION_HEADER *sections, **sorted;
 360         int num_regions, num_sections, i;
 361         int ctidx = IMAGE_DIRECTORY_ENTRY_SECURITY;
 362         u32 align, size, authsz, authoff;
 363         size_t bytes_hashed;
 364
 365         dos = (void *)efi;
 366         nt = (void *)(efi + dos->e_lfanew);
 367         authoff = 0;
 368         authsz = 0;
 369
 370         /*
 371          * Count maximum number of regions to be digested.
 372          * We don't have to have an exact number here.
 373          * See efi_image_region_add()'s in parsing below.
 374          */
 375         num_regions = 3; /* for header */
 376         num_regions += nt->FileHeader.NumberOfSections;
 377         num_regions++; /* for extra */
 378
 379         regs = calloc(sizeof(*regs) + sizeof(struct image_region) * num_regions,
 380                       1);
 381         if (!regs)
 382                 goto err;
 383         regs->max = num_regions;
 384
 385         /*
 386          * Collect data regions for hash calculation
 387          * 1. File headers
 388          */
 389         if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
 390                 IMAGE_NT_HEADERS64 *nt64 = (void *)nt;
 391                 IMAGE_OPTIONAL_HEADER64 *opt = &nt64->OptionalHeader;
 392
 393                 /* Skip CheckSum */
 394                 efi_image_region_add(regs, efi, &opt->CheckSum, 0);
 395                 if (nt64->OptionalHeader.NumberOfRvaAndSizes <= ctidx) {
 396                         efi_image_region_add(regs,
 397                                              &opt->Subsystem,
 398                                              efi + opt->SizeOfHeaders, 0);
 399                 } else {
 400                         /* Skip Certificates Table */
 401                         efi_image_region_add(regs,
 402                                              &opt->Subsystem,
 403                                              &opt->DataDirectory[ctidx], 0);
 404                         efi_image_region_add(regs,
 405                                              &opt->DataDirectory[ctidx] + 1,
 406                                              efi + opt->SizeOfHeaders, 0);
 407
 408                         authoff = opt->DataDirectory[ctidx].VirtualAddress;
 409                         authsz = opt->DataDirectory[ctidx].Size;
 410                 }
 411
 412                 bytes_hashed = opt->SizeOfHeaders;
 413                 align = opt->FileAlignment;
 414         } else if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
 415                 IMAGE_OPTIONAL_HEADER32 *opt = &nt->OptionalHeader;
 416
 417                 /* Skip CheckSum */
 418                 efi_image_region_add(regs, efi, &opt->CheckSum, 0);
 419                 if (nt->OptionalHeader.NumberOfRvaAndSizes <= ctidx) {
 420                         efi_image_region_add(regs,
 421                                              &opt->Subsystem,
 422                                              efi + opt->SizeOfHeaders, 0);
 423                 } else {
 424                         /* Skip Certificates Table */
 425                         efi_image_region_add(regs, &opt->Subsystem,
 426                                              &opt->DataDirectory[ctidx], 0);
 427                         efi_image_region_add(regs,
 428                                              &opt->DataDirectory[ctidx] + 1,
 429                                              efi + opt->SizeOfHeaders, 0);
 430
 431                         authoff = opt->DataDirectory[ctidx].VirtualAddress;
 432                         authsz = opt->DataDirectory[ctidx].Size;
 433                 }
 434
 435                 bytes_hashed = opt->SizeOfHeaders;
 436                 align = opt->FileAlignment;
 437         } else {
 438                 log_err("%s: Invalid optional header magic %x\n", __func__,
 439                         nt->OptionalHeader.Magic);
 440                 goto err;
 441         }
 442
 443         /* 2. Sections */
 444         num_sections = nt->FileHeader.NumberOfSections;
 445         sections = (void *)((uint8_t *)&nt->OptionalHeader +
 446                             nt->FileHeader.SizeOfOptionalHeader);
 447         sorted = calloc(sizeof(IMAGE_SECTION_HEADER *), num_sections);
 448         if (!sorted) {
 449                 log_err("%s: Out of memory\n", __func__);
 450                 goto err;
 451         }
 452
 453         /*
 454          * Make sure the section list is in ascending order.
 455          */
 456         for (i = 0; i < num_sections; i++)
 457                 sorted[i] = &sections[i];
 458         qsort(sorted, num_sections, sizeof(sorted[0]), cmp_pe_section);
 459
 460         for (i = 0; i < num_sections; i++) {
 461                 if (!sorted[i]->SizeOfRawData)
 462                         continue;
 463
 464                 size = (sorted[i]->SizeOfRawData + align - 1) & ~(align - 1);
 465                 efi_image_region_add(regs, efi + sorted[i]->PointerToRawData,
 466                                      efi + sorted[i]->PointerToRawData + size,
 467                                      0);
 468                 log_debug("section[%d](%s): raw: 0x%x-0x%x, virt: %x-%x\n",
 469                           i, sorted[i]->Name,
 470                           sorted[i]->PointerToRawData,
 471                           sorted[i]->PointerToRawData + size,
 472                           sorted[i]->VirtualAddress,
 473                           sorted[i]->VirtualAddress
 474                             + sorted[i]->Misc.VirtualSize);
 475
 476                 bytes_hashed += size;
 477         }
 478         free(sorted);
 479
 480         /* 3. Extra data excluding Certificates Table */
 481         if (bytes_hashed + authsz < len) {
 482                 log_debug("extra data for hash: %zu\n",
 483                           len - (bytes_hashed + authsz));
 484                 efi_image_region_add(regs, efi + bytes_hashed,
 485                                      efi + len - authsz, 0);
 486         }
 487
 488         /* Return Certificates Table */
 489         if (authsz) {
 490                 if (len < authoff + authsz) {
 491                         log_err("%s: Size for auth too large: %u >= %zu\n",
 492                                 __func__, authsz, len - authoff);
 493                         goto err;
 494                 }
 495                 if (authsz < sizeof(*auth)) {
 496                         log_err("%s: Size for auth too small: %u < %zu\n",
 497                                 __func__, authsz, sizeof(*auth));
 498                         goto err;
 499                 }
 500                 *auth = efi + authoff;
 501                 *auth_len = authsz;
 502                 log_debug("WIN_CERTIFICATE: 0x%x, size: 0x%x\n", authoff,
 503                           authsz);
 504         } else {
 505                 *auth = NULL;
 506                 *auth_len = 0;
 507         }
 508
 509         *regp = regs;
 510
 511         return true;
 512
 513 err:
 514         free(regs);
 515
 516         return false;
 517 }
 518
 519 #ifdef CONFIG_EFI_SECURE_BOOT
 520 /**
 521  * efi_image_verify_digest - verify image's message digest
 522  * @regs:       Array of memory regions to digest
 523  * @msg:        Signature in pkcs7 structure
 524  *
 525  * @regs contains all the data in a PE image to digest. Calculate
 526  * a hash value based on @regs and compare it with a messaged digest
 527  * in the content (SpcPeImageData) of @msg's contentInfo.
 528  *
 529  * Return:      true if verified, false if not
 530  */
 531 static bool efi_image_verify_digest(struct efi_image_regions *regs,
 532                                     struct pkcs7_message *msg)
 533 {
 534         struct pefile_context ctx;
 535         void *hash;
 536         int hash_len, ret;
 537
 538         const void *data;
 539         size_t data_len;
 540         size_t asn1hdrlen;
 541
 542         /* get pkcs7's contentInfo */
 543         ret = pkcs7_get_content_data(msg, &data, &data_len, &asn1hdrlen);
 544         if (ret < 0 || !data)
 545                 return false;
 546
 547         /* parse data and retrieve a message digest into ctx */
 548         ret = mscode_parse(&ctx, data, data_len, asn1hdrlen);
 549         if (ret < 0)
 550                 return false;
 551
 552         /* calculate a hash value of PE image */
 553         hash = NULL;
 554         if (!efi_hash_regions(regs->reg, regs->num, &hash, ctx.digest_algo,
 555                               &hash_len))
 556                 return false;
 557
 558         /* match the digest */
 559         if (ctx.digest_len != hash_len || memcmp(ctx.digest, hash, hash_len))
 560                 return false;
 561
 562         return true;
 563 }
 564
 565 /**
 566  * efi_image_authenticate() - verify a signature of signed image
 567  * @efi:        Pointer to image
 568  * @efi_size:   Size of @efi
 569  *
 570  * A signed image should have its signature stored in a table of its PE header.
 571  * So if an image is signed and only if if its signature is verified using
 572  * signature databases, an image is authenticated.
 573  * If an image is not signed, its validity is checked by using
 574  * efi_image_unsigned_authenticated().
 575  * TODO:
 576  * When AuditMode==0, if the image's signature is not found in
 577  * the authorized database, or is found in the forbidden database,
 578  * the image will not be started and instead, information about it
 579  * will be placed in this table.
 580  * When AuditMode==1, an EFI_IMAGE_EXECUTION_INFO element is created
 581  * in the EFI_IMAGE_EXECUTION_INFO_TABLE for every certificate found
 582  * in the certificate table of every image that is validated.
 583  *
 584  * Return:      true if authenticated, false if not
 585  */
 586 static bool efi_image_authenticate(void *efi, size_t efi_size)
 587 {
 588         struct efi_image_regions *regs = NULL;
 589         WIN_CERTIFICATE *wincerts = NULL, *wincert;
 590         size_t wincerts_len;
 591         struct pkcs7_message *msg = NULL;
 592         struct efi_signature_store *db = NULL, *dbx = NULL;
 593         void *new_efi = NULL;
 594         u8 *auth, *wincerts_end;
 595         size_t auth_size;
 596         bool ret = false;
 597
 598         log_debug("%s: Enter, %d\n", __func__, ret);
 599
 600         if (!efi_secure_boot_enabled())
 601                 return true;
 602
 603         new_efi = efi_prepare_aligned_image(efi, (u64 *)&efi_size);
 604         if (!new_efi)
 605                 return false;
 606
 607         if (!efi_image_parse(new_efi, efi_size, &regs, &wincerts,
 608                              &wincerts_len)) {
 609                 log_err("Parsing PE executable image failed\n");
 610                 goto out;
 611         }
 612
 613         /*
 614          * verify signature using db and dbx
 615          */
 616         db = efi_sigstore_parse_sigdb(u"db");
 617         if (!db) {
 618                 log_err("Getting signature database(db) failed\n");
 619                 goto out;
 620         }
 621
 622         dbx = efi_sigstore_parse_sigdb(u"dbx");
 623         if (!dbx) {
 624                 log_err("Getting signature database(dbx) failed\n");
 625                 goto out;
 626         }
 627
 628         if (efi_signature_lookup_digest(regs, dbx, true)) {
 629                 log_debug("Image's digest was found in \"dbx\"\n");
 630                 goto out;
 631         }
 632
 633         /*
 634          * go through WIN_CERTIFICATE list
 635          * NOTE:
 636          * We may have multiple signatures either as WIN_CERTIFICATE's
 637          * in PE header, or as pkcs7 SignerInfo's in SignedData.
 638          * So the verification policy here is:
 639          *   - Success if, at least, one of signatures is verified
 640          *   - unless signature is rejected explicitly with its digest.
 641          */
 642
 643         for (wincert = wincerts, wincerts_end = (u8 *)wincerts + wincerts_len;
 644              (u8 *)wincert < wincerts_end;
 645              wincert = (WIN_CERTIFICATE *)
 646                         ((u8 *)wincert + ALIGN(wincert->dwLength, 8))) {
 647                 if ((u8 *)wincert + sizeof(*wincert) >= wincerts_end)
 648                         break;
 649
 650                 if (wincert->dwLength <= sizeof(*wincert)) {
 651                         log_debug("dwLength too small: %u < %zu\n",
 652                                   wincert->dwLength, sizeof(*wincert));
 653                         continue;
 654                 }
 655
 656                 log_debug("WIN_CERTIFICATE_TYPE: 0x%x\n",
 657                           wincert->wCertificateType);
 658
 659                 auth = (u8 *)wincert + sizeof(*wincert);
 660                 auth_size = wincert->dwLength - sizeof(*wincert);
 661                 if (wincert->wCertificateType == WIN_CERT_TYPE_EFI_GUID) {
 662                         if (auth + sizeof(efi_guid_t) >= wincerts_end)
 663                                 break;
 664
 665                         if (auth_size <= sizeof(efi_guid_t)) {
 666                                 log_debug("dwLength too small: %u < %zu\n",
 667                                           wincert->dwLength, sizeof(*wincert));
 668                                 continue;
 669                         }
 670                         if (guidcmp(auth, &efi_guid_cert_type_pkcs7)) {
 671                                 log_debug("Certificate type not supported: %pUs\n",
 672                                           auth);
 673                                 ret = false;
 674                                 goto out;
 675                         }
 676
 677                         auth += sizeof(efi_guid_t);
 678                         auth_size -= sizeof(efi_guid_t);
 679                 } else if (wincert->wCertificateType
 680                                 != WIN_CERT_TYPE_PKCS_SIGNED_DATA) {
 681                         log_debug("Certificate type not supported\n");
 682                         ret = false;
 683                         goto out;
 684                 }
 685
 686                 msg = pkcs7_parse_message(auth, auth_size);
 687                 if (IS_ERR(msg)) {
 688                         log_err("Parsing image's signature failed\n");
 689                         msg = NULL;
 690                         continue;
 691                 }
 692
 693                 /*
 694                  * verify signatures in pkcs7's signedInfos which are
 695                  * to authenticate the integrity of pkcs7's contentInfo.
 696                  *
 697                  * NOTE:
 698                  * UEFI specification defines two signature types possible
 699                  * in signature database:
 700                  * a. x509 certificate, where a signature in image is
 701                  *    a message digest encrypted by RSA public key
 702                  *    (EFI_CERT_X509_GUID)
 703                  * b. bare hash value of message digest
 704                  *    (EFI_CERT_SHAxxx_GUID)
 705                  *
 706                  * efi_signature_verify() handles case (a), while
 707                  * efi_signature_lookup_digest() handles case (b).
 708                  *
 709                  * There is a third type:
 710                  * c. message digest of a certificate
 711                  *    (EFI_CERT_X509_SHAAxxx_GUID)
 712                  * This type of signature is used only in revocation list
 713                  * (dbx) and handled as part of efi_signatgure_verify().
 714                  */
 715                 /* try black-list first */
 716                 if (efi_signature_verify_one(regs, msg, dbx)) {
 717                         ret = false;
 718                         log_debug("Signature was rejected by \"dbx\"\n");
 719                         goto out;
 720                 }
 721
 722                 if (!efi_signature_check_signers(msg, dbx)) {
 723                         ret = false;
 724                         log_debug("Signer(s) in \"dbx\"\n");
 725                         goto out;
 726                 }
 727
 728                 /* try white-list */
 729                 if (!efi_signature_verify(regs, msg, db, dbx)) {
 730                         log_debug("Signature was not verified by \"db\"\n");
 731                         continue;
 732                 }
 733
 734                 /*
 735                  * now calculate an image's hash value and compare it with
 736                  * a messaged digest embedded in pkcs7's contentInfo
 737                  */
 738                 if (efi_image_verify_digest(regs, msg)) {
 739                         ret = true;
 740                         continue;
 741                 }
 742
 743                 log_debug("Message digest doesn't match\n");
 744         }
 745
 746
 747         /* last resort try the image sha256 hash in db */
 748         if (!ret && efi_signature_lookup_digest(regs, db, false))
 749                 ret = true;
 750
 751 out:
 752         efi_sigstore_free(db);
 753         efi_sigstore_free(dbx);
 754         pkcs7_free_message(msg);
 755         free(regs);
 756         if (new_efi != efi)
 757                 free(new_efi);
 758
 759         log_debug("%s: Exit, %d\n", __func__, ret);
 760         return ret;
 761 }
 762 #else
 763 static bool efi_image_authenticate(void *efi, size_t efi_size)
 764 {
 765         return true;
 766 }
 767 #endif /* CONFIG_EFI_SECURE_BOOT */
 768
 769
 770 /**
 771  * efi_check_pe() - check if a memory buffer contains a PE-COFF image
 772  *
 773  * @buffer:     buffer to check
 774  * @size:       size of buffer
 775  * @nt_header:  on return pointer to NT header of PE-COFF image
 776  * Return:      EFI_SUCCESS if the buffer contains a PE-COFF image
 777  */
 778 efi_status_t efi_check_pe(void *buffer, size_t size, void **nt_header)
 779 {
 780         IMAGE_DOS_HEADER *dos = buffer;
 781         IMAGE_NT_HEADERS32 *nt;
 782
 783         if (size < sizeof(*dos))
 784                 return EFI_INVALID_PARAMETER;
 785
 786         /* Check for DOS magix */
 787         if (dos->e_magic != IMAGE_DOS_SIGNATURE)
 788                 return EFI_INVALID_PARAMETER;
 789
 790         /*
 791          * Check if the image section header fits into the file. Knowing that at
 792          * least one section header follows we only need to check for the length
 793          * of the 64bit header which is longer than the 32bit header.
 794          */
 795         if (size < dos->e_lfanew + sizeof(IMAGE_NT_HEADERS32))
 796                 return EFI_INVALID_PARAMETER;
 797         nt = (IMAGE_NT_HEADERS32 *)((u8 *)buffer + dos->e_lfanew);
 798
 799         /* Check for PE-COFF magic */
 800         if (nt->Signature != IMAGE_NT_SIGNATURE)
 801                 return EFI_INVALID_PARAMETER;
 802
 803         if (nt_header)
 804                 *nt_header = nt;
 805
 806         return EFI_SUCCESS;
 807 }
 808
 809 /**
 810  * section_size() - determine size of section
 811  *
 812  * The size of a section in memory if normally given by VirtualSize.
 813  * If VirtualSize is not provided, use SizeOfRawData.
 814  *
 815  * @sec:        section header
 816  * Return:      size of section in memory
 817  */
 818 static u32 section_size(IMAGE_SECTION_HEADER *sec)
 819 {
 820         if (sec->Misc.VirtualSize)
 821                 return sec->Misc.VirtualSize;
 822         else
 823                 return sec->SizeOfRawData;
 824 }
 825
 826 /**
 827  * efi_load_pe() - relocate EFI binary
 828  *
 829  * This function loads all sections from a PE binary into a newly reserved
 830  * piece of memory. On success the entry point is returned as handle->entry.
 831  *
 832  * @handle:             loaded image handle
 833  * @efi:                pointer to the EFI binary
 834  * @efi_size:           size of @efi binary
 835  * @loaded_image_info:  loaded image protocol
 836  * Return:              status code
 837  */
 838 efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle,
 839                          void *efi, size_t efi_size,
 840                          struct efi_loaded_image *loaded_image_info)
 841 {
 842         IMAGE_NT_HEADERS32 *nt;
 843         IMAGE_DOS_HEADER *dos;
 844         IMAGE_SECTION_HEADER *sections;
 845         int num_sections;
 846         void *efi_reloc;
 847         int i;
 848         const IMAGE_BASE_RELOCATION *rel;
 849         unsigned long rel_size;
 850         int rel_idx = IMAGE_DIRECTORY_ENTRY_BASERELOC;
 851         uint64_t image_base;
 852         unsigned long virt_size = 0;
 853         int supported = 0;
 854         efi_status_t ret;
 855
 856         ret = efi_check_pe(efi, efi_size, (void **)&nt);
 857         if (ret != EFI_SUCCESS) {
 858                 log_err("Not a PE-COFF file\n");
 859                 return EFI_LOAD_ERROR;
 860         }
 861
 862         for (i = 0; machines[i]; i++)
 863                 if (machines[i] == nt->FileHeader.Machine) {
 864                         supported = 1;
 865                         break;
 866                 }
 867
 868         if (!supported) {
 869                 log_err("Machine type 0x%04x is not supported\n",
 870                         nt->FileHeader.Machine);
 871                 return EFI_LOAD_ERROR;
 872         }
 873
 874         num_sections = nt->FileHeader.NumberOfSections;
 875         sections = (void *)&nt->OptionalHeader +
 876                             nt->FileHeader.SizeOfOptionalHeader;
 877
 878         if (efi_size < ((void *)sections + sizeof(sections[0]) * num_sections
 879                         - efi)) {
 880                 log_err("Invalid number of sections: %d\n", num_sections);
 881                 return EFI_LOAD_ERROR;
 882         }
 883
 884         /* Authenticate an image */
 885         if (efi_image_authenticate(efi, efi_size)) {
 886                 handle->auth_status = EFI_IMAGE_AUTH_PASSED;
 887         } else {
 888                 handle->auth_status = EFI_IMAGE_AUTH_FAILED;
 889                 log_err("Image not authenticated\n");
 890         }
 891
 892         /* Calculate upper virtual address boundary */
 893         for (i = num_sections - 1; i >= 0; i--) {
 894                 IMAGE_SECTION_HEADER *sec = &sections[i];
 895
 896                 virt_size = max_t(unsigned long, virt_size,
 897                                   sec->VirtualAddress + section_size(sec));
 898         }
 899
 900         /* Read 32/64bit specific header bits */
 901         if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
 902                 IMAGE_NT_HEADERS64 *nt64 = (void *)nt;
 903                 IMAGE_OPTIONAL_HEADER64 *opt = &nt64->OptionalHeader;
 904                 image_base = opt->ImageBase;
 905                 efi_set_code_and_data_type(loaded_image_info, opt->Subsystem);
 906                 handle->image_type = opt->Subsystem;
 907                 efi_reloc = efi_alloc_aligned_pages(virt_size,
 908                                                     loaded_image_info->image_code_type,
 909                                                     opt->SectionAlignment);
 910                 if (!efi_reloc) {
 911                         log_err("Out of memory\n");
 912                         ret = EFI_OUT_OF_RESOURCES;
 913                         goto err;
 914                 }
 915                 handle->entry = efi_reloc + opt->AddressOfEntryPoint;
 916                 rel_size = opt->DataDirectory[rel_idx].Size;
 917                 rel = efi_reloc + opt->DataDirectory[rel_idx].VirtualAddress;
 918         } else if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
 919                 IMAGE_OPTIONAL_HEADER32 *opt = &nt->OptionalHeader;
 920                 image_base = opt->ImageBase;
 921                 efi_set_code_and_data_type(loaded_image_info, opt->Subsystem);
 922                 handle->image_type = opt->Subsystem;
 923                 efi_reloc = efi_alloc_aligned_pages(virt_size,
 924                                                     loaded_image_info->image_code_type,
 925                                                     opt->SectionAlignment);
 926                 if (!efi_reloc) {
 927                         log_err("Out of memory\n");
 928                         ret = EFI_OUT_OF_RESOURCES;
 929                         goto err;
 930                 }
 931                 handle->entry = efi_reloc + opt->AddressOfEntryPoint;
 932                 rel_size = opt->DataDirectory[rel_idx].Size;
 933                 rel = efi_reloc + opt->DataDirectory[rel_idx].VirtualAddress;
 934         } else {
 935                 log_err("Invalid optional header magic %x\n",
 936                         nt->OptionalHeader.Magic);
 937                 ret = EFI_LOAD_ERROR;
 938                 goto err;
 939         }
 940
 941 #if IS_ENABLED(CONFIG_EFI_TCG2_PROTOCOL)
 942         /* Measure an PE/COFF image */
 943         ret = tcg2_measure_pe_image(efi, efi_size, handle, loaded_image_info);
 944         if (ret == EFI_SECURITY_VIOLATION) {
 945                 /*
 946                  * TCG2 Protocol is installed but no TPM device found,
 947                  * this is not expected.
 948                  */
 949                 log_err("PE image measurement failed, no tpm device found\n");
 950                 goto err;
 951         }
 952
 953 #endif
 954
 955         /* Copy PE headers */
 956         memcpy(efi_reloc, efi,
 957                sizeof(*dos)
 958                  + sizeof(*nt)
 959                  + nt->FileHeader.SizeOfOptionalHeader
 960                  + num_sections * sizeof(IMAGE_SECTION_HEADER));
 961
 962         /* Load sections into RAM */
 963         for (i = num_sections - 1; i >= 0; i--) {
 964                 IMAGE_SECTION_HEADER *sec = &sections[i];
 965                 u32 copy_size = section_size(sec);
 966
 967                 if (copy_size > sec->SizeOfRawData) {
 968                         copy_size = sec->SizeOfRawData;
 969                         memset(efi_reloc + sec->VirtualAddress, 0,
 970                                sec->Misc.VirtualSize);
 971                 }
 972                 memcpy(efi_reloc + sec->VirtualAddress,
 973                        efi + sec->PointerToRawData,
 974                        copy_size);
 975         }
 976
 977         /* Run through relocations */
 978         if (efi_loader_relocate(rel, rel_size, efi_reloc,
 979                                 (unsigned long)image_base) != EFI_SUCCESS) {
 980                 efi_free_pages((uintptr_t) efi_reloc,
 981                                (virt_size + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT);
 982                 ret = EFI_LOAD_ERROR;
 983                 goto err;
 984         }
 985
 986         /* Flush cache */
 987         flush_cache((ulong)efi_reloc,
 988                     ALIGN(virt_size, EFI_CACHELINE_SIZE));
 989         invalidate_icache_all();
 990
 991         /* Populate the loaded image interface bits */
 992         loaded_image_info->image_base = efi_reloc;
 993         loaded_image_info->image_size = virt_size;
 994
 995         if (handle->auth_status == EFI_IMAGE_AUTH_PASSED)
 996                 return EFI_SUCCESS;
 997         else
 998                 return EFI_SECURITY_VIOLATION;
 999
1000 err:
1001         return ret;
1002 }