summaryrefslogtreecommitdiff
path: root/lib/efi_loader/efi_image_loader.c
blob: 5dd601908d524652e41dc5b3813324a62c7f963b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
// SPDX-License-Identifier: GPL-2.0+
/*
 *  EFI image loader
 *
 *  based partly on wine code
 *
 *  Copyright (c) 2016 Alexander Graf
 */

#include <common.h>
#include <cpu_func.h>
#include <efi_loader.h>
#include <malloc.h>
#include <pe.h>
#include <sort.h>
#include <crypto/pkcs7_parser.h>
#include <linux/err.h>

const efi_guid_t efi_global_variable_guid = EFI_GLOBAL_VARIABLE_GUID;
const efi_guid_t efi_guid_device_path = EFI_DEVICE_PATH_PROTOCOL_GUID;
const efi_guid_t efi_guid_loaded_image = EFI_LOADED_IMAGE_PROTOCOL_GUID;
const efi_guid_t efi_guid_loaded_image_device_path =
		EFI_LOADED_IMAGE_DEVICE_PATH_PROTOCOL_GUID;
const efi_guid_t efi_simple_file_system_protocol_guid =
		EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
const efi_guid_t efi_file_info_guid = EFI_FILE_INFO_GUID;

static int machines[] = {
#if defined(__aarch64__)
	IMAGE_FILE_MACHINE_ARM64,
#elif defined(__arm__)
	IMAGE_FILE_MACHINE_ARM,
	IMAGE_FILE_MACHINE_THUMB,
	IMAGE_FILE_MACHINE_ARMNT,
#endif

#if defined(__x86_64__)
	IMAGE_FILE_MACHINE_AMD64,
#elif defined(__i386__)
	IMAGE_FILE_MACHINE_I386,
#endif

#if defined(__riscv) && (__riscv_xlen == 32)
	IMAGE_FILE_MACHINE_RISCV32,
#endif

#if defined(__riscv) && (__riscv_xlen == 64)
	IMAGE_FILE_MACHINE_RISCV64,
#endif
	0 };

/**
 * efi_print_image_info() - print information about a loaded image
 *
 * If the program counter is located within the image the offset to the base
 * address is shown.
 *
 * @obj:	EFI object
 * @image:	loaded image
 * @pc:		program counter (use NULL to suppress offset output)
 * Return:	status code
 */
static efi_status_t efi_print_image_info(struct efi_loaded_image_obj *obj,
					 struct efi_loaded_image *image,
					 void *pc)
{
	printf("UEFI image");
	printf(" [0x%p:0x%p]",
	       image->image_base, image->image_base + image->image_size - 1);
	if (pc && pc >= image->image_base &&
	    pc < image->image_base + image->image_size)
		printf(" pc=0x%zx", pc - image->image_base);
	if (image->file_path)
		printf(" '%pD'", image->file_path);
	printf("\n");
	return EFI_SUCCESS;
}

/**
 * efi_print_image_infos() - print information about all loaded images
 *
 * @pc:		program counter (use NULL to suppress offset output)
 */
void efi_print_image_infos(void *pc)
{
	struct efi_object *efiobj;
	struct efi_handler *handler;

	list_for_each_entry(efiobj, &efi_obj_list, link) {
		list_for_each_entry(handler, &efiobj->protocols, link) {
			if (!guidcmp(handler->guid, &efi_guid_loaded_image)) {
				efi_print_image_info(
					(struct efi_loaded_image_obj *)efiobj,
					handler->protocol_interface, pc);
			}
		}
	}
}

/**
 * efi_loader_relocate() - relocate UEFI binary
 *
 * @rel:		pointer to the relocation table
 * @rel_size:		size of the relocation table in bytes
 * @efi_reloc:		actual load address of the image
 * @pref_address:	preferred load address of the image
 * Return:		status code
 */
static efi_status_t efi_loader_relocate(const IMAGE_BASE_RELOCATION *rel,
			unsigned long rel_size, void *efi_reloc,
			unsigned long pref_address)
{
	unsigned long delta = (unsigned long)efi_reloc - pref_address;
	const IMAGE_BASE_RELOCATION *end;
	int i;

	if (delta == 0)
		return EFI_SUCCESS;

	end = (const IMAGE_BASE_RELOCATION *)((const char *)rel + rel_size);
	while (rel < end && rel->SizeOfBlock) {
		const uint16_t *relocs = (const uint16_t *)(rel + 1);
		i = (rel->SizeOfBlock - sizeof(*rel)) / sizeof(uint16_t);
		while (i--) {
			uint32_t offset = (uint32_t)(*relocs & 0xfff) +
					  rel->VirtualAddress;
			int type = *relocs >> EFI_PAGE_SHIFT;
			uint64_t *x64 = efi_reloc + offset;
			uint32_t *x32 = efi_reloc + offset;
			uint16_t *x16 = efi_reloc + offset;

			switch (type) {
			case IMAGE_REL_BASED_ABSOLUTE:
				break;
			case IMAGE_REL_BASED_HIGH:
				*x16 += ((uint32_t)delta) >> 16;
				break;
			case IMAGE_REL_BASED_LOW:
				*x16 += (uint16_t)delta;
				break;
			case IMAGE_REL_BASED_HIGHLOW:
				*x32 += (uint32_t)delta;
				break;
			case IMAGE_REL_BASED_DIR64:
				*x64 += (uint64_t)delta;
				break;
#ifdef __riscv
			case IMAGE_REL_BASED_RISCV_HI20:
				*x32 = ((*x32 & 0xfffff000) + (uint32_t)delta) |
					(*x32 & 0x00000fff);
				break;
			case IMAGE_REL_BASED_RISCV_LOW12I:
			case IMAGE_REL_BASED_RISCV_LOW12S:
				/* We know that we're 4k aligned */
				if (delta & 0xfff) {
					printf("Unsupported reloc offset\n");
					return EFI_LOAD_ERROR;
				}
				break;
#endif
			default:
				printf("Unknown Relocation off %x type %x\n",
				       offset, type);
				return EFI_LOAD_ERROR;
			}
			relocs++;
		}
		rel = (const IMAGE_BASE_RELOCATION *)relocs;
	}
	return EFI_SUCCESS;
}

void __weak invalidate_icache_all(void)
{
	/* If the system doesn't support icache_all flush, cross our fingers */
}

/**
 * efi_set_code_and_data_type() - determine the memory types to be used for code
 *				  and data.
 *
 * @loaded_image_info:	image descriptor
 * @image_type:		field Subsystem of the optional header for
 *			Windows specific field
 */
static void efi_set_code_and_data_type(
			struct efi_loaded_image *loaded_image_info,
			uint16_t image_type)
{
	switch (image_type) {
	case IMAGE_SUBSYSTEM_EFI_APPLICATION:
		loaded_image_info->image_code_type = EFI_LOADER_CODE;
		loaded_image_info->image_data_type = EFI_LOADER_DATA;
		break;
	case IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER:
		loaded_image_info->image_code_type = EFI_BOOT_SERVICES_CODE;
		loaded_image_info->image_data_type = EFI_BOOT_SERVICES_DATA;
		break;
	case IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER:
	case IMAGE_SUBSYSTEM_EFI_ROM:
		loaded_image_info->image_code_type = EFI_RUNTIME_SERVICES_CODE;
		loaded_image_info->image_data_type = EFI_RUNTIME_SERVICES_DATA;
		break;
	default:
		printf("%s: invalid image type: %u\n", __func__, image_type);
		/* Let's assume it is an application */
		loaded_image_info->image_code_type = EFI_LOADER_CODE;
		loaded_image_info->image_data_type = EFI_LOADER_DATA;
		break;
	}
}

#ifdef CONFIG_EFI_SECURE_BOOT
/**
 * cmp_pe_section - compare two sections
 * @arg1:	Pointer to pointer to first section
 * @arg2:	Pointer to pointer to second section
 *
 * Compare two sections in PE image.
 *
 * Return:	-1, 0, 1 respectively if arg1 < arg2, arg1 == arg2 or
 *		arg1 > arg2
 */
static int cmp_pe_section(const void *arg1, const void *arg2)
{
	const IMAGE_SECTION_HEADER *section1, *section2;

	section1 = *((const IMAGE_SECTION_HEADER **)arg1);
	section2 = *((const IMAGE_SECTION_HEADER **)arg2);

	if (section1->VirtualAddress < section2->VirtualAddress)
		return -1;
	else if (section1->VirtualAddress == section2->VirtualAddress)
		return 0;
	else
		return 1;
}

/**
 * efi_image_parse - parse a PE image
 * @efi:	Pointer to image
 * @len:	Size of @efi
 * @regp:	Pointer to a list of regions
 * @auth:	Pointer to a pointer to authentication data in PE
 * @auth_len:	Size of @auth
 *
 * Parse image binary in PE32(+) format, assuming that sanity of PE image
 * has been checked by a caller.
 * On success, an address of authentication data in @efi and its size will
 * be returned in @auth and @auth_len, respectively.
 *
 * Return:	true on success, false on error
 */
bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,
		     WIN_CERTIFICATE **auth, size_t *auth_len)
{
	struct efi_image_regions *regs;
	IMAGE_DOS_HEADER *dos;
	IMAGE_NT_HEADERS32 *nt;
	IMAGE_SECTION_HEADER *sections, **sorted;
	int num_regions, num_sections, i;
	int ctidx = IMAGE_DIRECTORY_ENTRY_SECURITY;
	u32 align, size, authsz, authoff;
	size_t bytes_hashed;

	dos = (void *)efi;
	nt = (void *)(efi + dos->e_lfanew);

	/*
	 * Count maximum number of regions to be digested.
	 * We don't have to have an exact number here.
	 * See efi_image_region_add()'s in parsing below.
	 */
	num_regions = 3; /* for header */
	num_regions += nt->FileHeader.NumberOfSections;
	num_regions++; /* for extra */

	regs = calloc(sizeof(*regs) + sizeof(struct image_region) * num_regions,
		      1);
	if (!regs)
		goto err;
	regs->max = num_regions;

	/*
	 * Collect data regions for hash calculation
	 * 1. File headers
	 */
	if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
		IMAGE_NT_HEADERS64 *nt64 = (void *)nt;
		IMAGE_OPTIONAL_HEADER64 *opt = &nt64->OptionalHeader;

		/* Skip CheckSum */
		efi_image_region_add(regs, efi, &opt->CheckSum, 0);
		if (nt64->OptionalHeader.NumberOfRvaAndSizes <= ctidx) {
			efi_image_region_add(regs,
					     &opt->Subsystem,
					     efi + opt->SizeOfHeaders, 0);
		} else {
			/* Skip Certificates Table */
			efi_image_region_add(regs,
					     &opt->Subsystem,
					     &opt->DataDirectory[ctidx], 0);
			efi_image_region_add(regs,
					     &opt->DataDirectory[ctidx] + 1,
					     efi + opt->SizeOfHeaders, 0);
		}

		bytes_hashed = opt->SizeOfHeaders;
		align = opt->FileAlignment;
		authoff = opt->DataDirectory[ctidx].VirtualAddress;
		authsz = opt->DataDirectory[ctidx].Size;
	} else if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
		IMAGE_OPTIONAL_HEADER32 *opt = &nt->OptionalHeader;

		efi_image_region_add(regs, efi, &opt->CheckSum, 0);
		efi_image_region_add(regs, &opt->Subsystem,
				     &opt->DataDirectory[ctidx], 0);
		efi_image_region_add(regs, &opt->DataDirectory[ctidx] + 1,
				     efi + opt->SizeOfHeaders, 0);

		bytes_hashed = opt->SizeOfHeaders;
		align = opt->FileAlignment;
		authoff = opt->DataDirectory[ctidx].VirtualAddress;
		authsz = opt->DataDirectory[ctidx].Size;
	} else {
		debug("%s: Invalid optional header magic %x\n", __func__,
		      nt->OptionalHeader.Magic);
		goto err;
	}

	/* 2. Sections */
	num_sections = nt->FileHeader.NumberOfSections;
	sections = (void *)((uint8_t *)&nt->OptionalHeader +
			    nt->FileHeader.SizeOfOptionalHeader);
	sorted = calloc(sizeof(IMAGE_SECTION_HEADER *), num_sections);
	if (!sorted) {
		debug("%s: Out of memory\n", __func__);
		goto err;
	}

	/*
	 * Make sure the section list is in ascending order.
	 */
	for (i = 0; i < num_sections; i++)
		sorted[i] = &sections[i];
	qsort(sorted, num_sections, sizeof(sorted[0]), cmp_pe_section);

	for (i = 0; i < num_sections; i++) {
		if (!sorted[i]->SizeOfRawData)
			continue;

		size = (sorted[i]->SizeOfRawData + align - 1) & ~(align - 1);
		efi_image_region_add(regs, efi + sorted[i]->PointerToRawData,
				     efi + sorted[i]->PointerToRawData + size,
				     0);
		debug("section[%d](%s): raw: 0x%x-0x%x, virt: %x-%x\n",
		      i, sorted[i]->Name,
		      sorted[i]->PointerToRawData,
		      sorted[i]->PointerToRawData + size,
		      sorted[i]->VirtualAddress,
		      sorted[i]->VirtualAddress
			+ sorted[i]->Misc.VirtualSize);

		bytes_hashed += size;
	}
	free(sorted);

	/* 3. Extra data excluding Certificates Table */
	if (bytes_hashed + authsz < len) {
		debug("extra data for hash: %lu\n",
		      len - (bytes_hashed + authsz));
		efi_image_region_add(regs, efi + bytes_hashed,
				     efi + len - authsz, 0);
	}

	/* Return Certificates Table */
	if (authsz) {
		if (len < authoff + authsz) {
			debug("%s: Size for auth too large: %u >= %zu\n",
			      __func__, authsz, len - authoff);
			goto err;
		}
		if (authsz < sizeof(*auth)) {
			debug("%s: Size for auth too small: %u < %zu\n",
			      __func__, authsz, sizeof(*auth));
			goto err;
		}
		*auth = efi + authoff;
		*auth_len = authsz;
		debug("WIN_CERTIFICATE: 0x%x, size: 0x%x\n", authoff, authsz);
	} else {
		*auth = NULL;
		*auth_len = 0;
	}

	*regp = regs;

	return true;

err:
	free(regs);

	return false;
}

/**
 * efi_image_unsigned_authenticate - authenticate unsigned image with
 * SHA256 hash
 * @regs:	List of regions to be verified
 *
 * If an image is not signed, it doesn't have a signature. In this case,
 * its message digest is calculated and it will be compared with one of
 * hash values stored in signature databases.
 *
 * Return:	true if authenticated, false if not
 */
static bool efi_image_unsigned_authenticate(struct efi_image_regions *regs)
{
	struct efi_signature_store *db = NULL, *dbx = NULL;
	bool ret = false;

	dbx = efi_sigstore_parse_sigdb(L"dbx");
	if (!dbx) {
		debug("Getting signature database(dbx) failed\n");
		goto out;
	}

	db = efi_sigstore_parse_sigdb(L"db");
	if (!db) {
		debug("Getting signature database(db) failed\n");
		goto out;
	}

	/* try black-list first */
	if (efi_signature_verify_with_sigdb(regs, NULL, dbx, NULL)) {
		debug("Image is not signed and rejected by \"dbx\"\n");
		goto out;
	}

	/* try white-list */
	if (efi_signature_verify_with_sigdb(regs, NULL, db, NULL))
		ret = true;
	else
		debug("Image is not signed and not found in \"db\" or \"dbx\"\n");

out:
	efi_sigstore_free(db);
	efi_sigstore_free(dbx);

	return ret;
}

/**
 * efi_image_authenticate - verify a signature of signed image
 * @efi:	Pointer to image
 * @efi_size:	Size of @efi
 *
 * A signed image should have its signature stored in a table of its PE header.
 * So if an image is signed and only if if its signature is verified using
 * signature databases, an image is authenticated.
 * If an image is not signed, its validity is checked by using
 * efi_image_unsigned_authenticated().
 * TODO:
 * When AuditMode==0, if the image's signature is not found in
 * the authorized database, or is found in the forbidden database,
 * the image will not be started and instead, information about it
 * will be placed in this table.
 * When AuditMode==1, an EFI_IMAGE_EXECUTION_INFO element is created
 * in the EFI_IMAGE_EXECUTION_INFO_TABLE for every certificate found
 * in the certificate table of every image that is validated.
 *
 * Return:	true if authenticated, false if not
 */
static bool efi_image_authenticate(void *efi, size_t efi_size)
{
	struct efi_image_regions *regs = NULL;
	WIN_CERTIFICATE *wincerts = NULL, *wincert;
	size_t wincerts_len;
	struct pkcs7_message *msg = NULL;
	struct efi_signature_store *db = NULL, *dbx = NULL;
	struct x509_certificate *cert = NULL;
	void *new_efi = NULL;
	size_t new_efi_size;
	bool ret = false;

	if (!efi_secure_boot_enabled())
		return true;

	/*
	 * Size must be 8-byte aligned and the trailing bytes must be
	 * zero'ed. Otherwise hash value may be incorrect.
	 */
	if (efi_size & 0x7) {
		new_efi_size = (efi_size + 0x7) & ~0x7ULL;
		new_efi = calloc(new_efi_size, 1);
		if (!new_efi)
			return false;
		memcpy(new_efi, efi, efi_size);
		efi = new_efi;
		efi_size = new_efi_size;
	}

	if (!efi_image_parse(efi, efi_size, &regs, &wincerts,
			     &wincerts_len)) {
		debug("Parsing PE executable image failed\n");
		goto err;
	}

	if (!wincerts) {
		/* The image is not signed */
		ret = efi_image_unsigned_authenticate(regs);

		goto err;
	}

	/*
	 * verify signature using db and dbx
	 */
	db = efi_sigstore_parse_sigdb(L"db");
	if (!db) {
		debug("Getting signature database(db) failed\n");
		goto err;
	}

	dbx = efi_sigstore_parse_sigdb(L"dbx");
	if (!dbx) {
		debug("Getting signature database(dbx) failed\n");
		goto err;
	}

	/* go through WIN_CERTIFICATE list */
	for (wincert = wincerts;
	     (void *)wincert < (void *)wincerts + wincerts_len;
	     wincert = (void *)wincert + ALIGN(wincert->dwLength, 8)) {
		if (wincert->dwLength < sizeof(*wincert)) {
			debug("%s: dwLength too small: %u < %zu\n",
			      __func__, wincert->dwLength, sizeof(*wincert));
			goto err;
		}
		msg = pkcs7_parse_message((void *)wincert + sizeof(*wincert),
					  wincert->dwLength - sizeof(*wincert));
		if (IS_ERR(msg)) {
			debug("Parsing image's signature failed\n");
			msg = NULL;
			goto err;
		}

		/* try black-list first */
		if (efi_signature_verify_with_sigdb(regs, msg, dbx, NULL)) {
			debug("Signature was rejected by \"dbx\"\n");
			goto err;
		}

		if (!efi_signature_verify_signers(msg, dbx)) {
			debug("Signer was rejected by \"dbx\"\n");
			goto err;
		} else {
			ret = true;
		}

		/* try white-list */
		if (!efi_signature_verify_with_sigdb(regs, msg, db, &cert)) {
			debug("Verifying signature with \"db\" failed\n");
			goto err;
		} else {
			ret = true;
		}

		if (!efi_signature_verify_cert(cert, dbx)) {
			debug("Certificate was rejected by \"dbx\"\n");
			goto err;
		} else {
			ret = true;
		}
	}

err:
	x509_free_certificate(cert);
	efi_sigstore_free(db);
	efi_sigstore_free(dbx);
	pkcs7_free_message(msg);
	free(regs);
	free(new_efi);

	return ret;
}
#else
static bool efi_image_authenticate(void *efi, size_t efi_size)
{
	return true;
}
#endif /* CONFIG_EFI_SECURE_BOOT */

/**
 * efi_load_pe() - relocate EFI binary
 *
 * This function loads all sections from a PE binary into a newly reserved
 * piece of memory. On success the entry point is returned as handle->entry.
 *
 * @handle:		loaded image handle
 * @efi:		pointer to the EFI binary
 * @efi_size:		size of @efi binary
 * @loaded_image_info:	loaded image protocol
 * Return:		status code
 */
efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle,
			 void *efi, size_t efi_size,
			 struct efi_loaded_image *loaded_image_info)
{
	IMAGE_NT_HEADERS32 *nt;
	IMAGE_DOS_HEADER *dos;
	IMAGE_SECTION_HEADER *sections;
	int num_sections;
	void *efi_reloc;
	int i;
	const IMAGE_BASE_RELOCATION *rel;
	unsigned long rel_size;
	int rel_idx = IMAGE_DIRECTORY_ENTRY_BASERELOC;
	uint64_t image_base;
	unsigned long virt_size = 0;
	int supported = 0;
	efi_status_t ret;

	/* Sanity check for a file header */
	if (efi_size < sizeof(*dos)) {
		printf("%s: Truncated DOS Header\n", __func__);
		ret = EFI_LOAD_ERROR;
		goto err;
	}

	dos = efi;
	if (dos->e_magic != IMAGE_DOS_SIGNATURE) {
		printf("%s: Invalid DOS Signature\n", __func__);
		ret = EFI_LOAD_ERROR;
		goto err;
	}

	/* assume sizeof(IMAGE_NT_HEADERS32) <= sizeof(IMAGE_NT_HEADERS64) */
	if (efi_size < dos->e_lfanew + sizeof(IMAGE_NT_HEADERS32)) {
		printf("%s: Invalid offset for Extended Header\n", __func__);
		ret = EFI_LOAD_ERROR;
		goto err;
	}

	nt = (void *) ((char *)efi + dos->e_lfanew);
	if ((nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) &&
	    (efi_size < dos->e_lfanew + sizeof(IMAGE_NT_HEADERS64))) {
		printf("%s: Invalid offset for Extended Header\n", __func__);
		ret = EFI_LOAD_ERROR;
		goto err;
	}

	if (nt->Signature != IMAGE_NT_SIGNATURE) {
		printf("%s: Invalid NT Signature\n", __func__);
		ret = EFI_LOAD_ERROR;
		goto err;
	}

	for (i = 0; machines[i]; i++)
		if (machines[i] == nt->FileHeader.Machine) {
			supported = 1;
			break;
		}

	if (!supported) {
		printf("%s: Machine type 0x%04x is not supported\n",
		       __func__, nt->FileHeader.Machine);
		ret = EFI_LOAD_ERROR;
		goto err;
	}

	num_sections = nt->FileHeader.NumberOfSections;
	sections = (void *)&nt->OptionalHeader +
			    nt->FileHeader.SizeOfOptionalHeader;

	if (efi_size < ((void *)sections + sizeof(sections[0]) * num_sections
			- efi)) {
		printf("%s: Invalid number of sections: %d\n",
		       __func__, num_sections);
		ret = EFI_LOAD_ERROR;
		goto err;
	}

	/* Authenticate an image */
	if (efi_image_authenticate(efi, efi_size))
		handle->auth_status = EFI_IMAGE_AUTH_PASSED;
	else
		handle->auth_status = EFI_IMAGE_AUTH_FAILED;

	/* Calculate upper virtual address boundary */
	for (i = num_sections - 1; i >= 0; i--) {
		IMAGE_SECTION_HEADER *sec = &sections[i];
		virt_size = max_t(unsigned long, virt_size,
				  sec->VirtualAddress + sec->Misc.VirtualSize);
	}

	/* Read 32/64bit specific header bits */
	if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
		IMAGE_NT_HEADERS64 *nt64 = (void *)nt;
		IMAGE_OPTIONAL_HEADER64 *opt = &nt64->OptionalHeader;
		image_base = opt->ImageBase;
		efi_set_code_and_data_type(loaded_image_info, opt->Subsystem);
		handle->image_type = opt->Subsystem;
		efi_reloc = efi_alloc(virt_size,
				      loaded_image_info->image_code_type);
		if (!efi_reloc) {
			printf("%s: Could not allocate %lu bytes\n",
			       __func__, virt_size);
			ret = EFI_OUT_OF_RESOURCES;
			goto err;
		}
		handle->entry = efi_reloc + opt->AddressOfEntryPoint;
		rel_size = opt->DataDirectory[rel_idx].Size;
		rel = efi_reloc + opt->DataDirectory[rel_idx].VirtualAddress;
		virt_size = ALIGN(virt_size, opt->SectionAlignment);
	} else if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
		IMAGE_OPTIONAL_HEADER32 *opt = &nt->OptionalHeader;
		image_base = opt->ImageBase;
		efi_set_code_and_data_type(loaded_image_info, opt->Subsystem);
		handle->image_type = opt->Subsystem;
		efi_reloc = efi_alloc(virt_size,
				      loaded_image_info->image_code_type);
		if (!efi_reloc) {
			printf("%s: Could not allocate %lu bytes\n",
			       __func__, virt_size);
			ret = EFI_OUT_OF_RESOURCES;
			goto err;
		}
		handle->entry = efi_reloc + opt->AddressOfEntryPoint;
		rel_size = opt->DataDirectory[rel_idx].Size;
		rel = efi_reloc + opt->DataDirectory[rel_idx].VirtualAddress;
		virt_size = ALIGN(virt_size, opt->SectionAlignment);
	} else {
		printf("%s: Invalid optional header magic %x\n", __func__,
		       nt->OptionalHeader.Magic);
		ret = EFI_LOAD_ERROR;
		goto err;
	}

	/* Copy PE headers */
	memcpy(efi_reloc, efi,
	       sizeof(*dos)
		 + sizeof(*nt)
		 + nt->FileHeader.SizeOfOptionalHeader
		 + num_sections * sizeof(IMAGE_SECTION_HEADER));

	/* Load sections into RAM */
	for (i = num_sections - 1; i >= 0; i--) {
		IMAGE_SECTION_HEADER *sec = &sections[i];
		memset(efi_reloc + sec->VirtualAddress, 0,
		       sec->Misc.VirtualSize);
		memcpy(efi_reloc + sec->VirtualAddress,
		       efi + sec->PointerToRawData,
		       sec->SizeOfRawData);
	}

	/* Run through relocations */
	if (efi_loader_relocate(rel, rel_size, efi_reloc,
				(unsigned long)image_base) != EFI_SUCCESS) {
		efi_free_pages((uintptr_t) efi_reloc,
			       (virt_size + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT);
		ret = EFI_LOAD_ERROR;
		goto err;
	}

	/* Flush cache */
	flush_cache((ulong)efi_reloc,
		    ALIGN(virt_size, EFI_CACHELINE_SIZE));
	invalidate_icache_all();

	/* Populate the loaded image interface bits */
	loaded_image_info->image_base = efi_reloc;
	loaded_image_info->image_size = virt_size;

	if (handle->auth_status == EFI_IMAGE_AUTH_PASSED)
		return EFI_SUCCESS;
	else
		return EFI_SECURITY_VIOLATION;

err:
	return ret;
}