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1 /** @file
2 Implement image verification services for secure boot service
3
4 Caution: This file requires additional review when modified.
5 This library will have external input - PE/COFF image.
6 This external input must be validated carefully to avoid security issue like
7 buffer overflow, integer overflow.
8
9 DxeImageVerificationLibImageRead() function will make sure the PE/COFF image content
10 read is within the image buffer.
11
12 DxeImageVerificationHandler(), HashPeImageByType(), HashPeImage() function will accept
13 untrusted PE/COFF image and validate its data structure within this image buffer before use.
14
15 Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved.<BR>
16 (C) Copyright 2016 Hewlett Packard Enterprise Development LP<BR>
17 SPDX-License-Identifier: BSD-2-Clause-Patent
18
19 **/
20
21 #include "DxeImageVerificationLib.h"
22
23 //
24 // Caution: This is used by a function which may receive untrusted input.
25 // These global variables hold PE/COFF image data, and they should be validated before use.
26 //
27 EFI_IMAGE_OPTIONAL_HEADER_PTR_UNION mNtHeader;
28 UINT32 mPeCoffHeaderOffset;
29 EFI_GUID mCertType;
30
31 //
32 // Information on current PE/COFF image
33 //
34 UINTN mImageSize;
35 UINT8 *mImageBase = NULL;
36 UINT8 mImageDigest[MAX_DIGEST_SIZE];
37 UINTN mImageDigestSize;
38
39 //
40 // Notify string for authorization UI.
41 //
42 CHAR16 mNotifyString1[MAX_NOTIFY_STRING_LEN] = L"Image verification pass but not found in authorized database!";
43 CHAR16 mNotifyString2[MAX_NOTIFY_STRING_LEN] = L"Launch this image anyway? (Yes/Defer/No)";
44 //
45 // Public Exponent of RSA Key.
46 //
47 CONST UINT8 mRsaE[] = { 0x01, 0x00, 0x01 };
48
49
50 //
51 // OID ASN.1 Value for Hash Algorithms
52 //
53 UINT8 mHashOidValue[] = {
54 0x2B, 0x0E, 0x03, 0x02, 0x1A, // OBJ_sha1
55 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04, // OBJ_sha224
56 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, // OBJ_sha256
57 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, // OBJ_sha384
58 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, // OBJ_sha512
59 };
60
61 HASH_TABLE mHash[] = {
62 { L"SHA1", 20, &mHashOidValue[0], 5, Sha1GetContextSize, Sha1Init, Sha1Update, Sha1Final },
63 { L"SHA224", 28, &mHashOidValue[5], 9, NULL, NULL, NULL, NULL },
64 { L"SHA256", 32, &mHashOidValue[14], 9, Sha256GetContextSize, Sha256Init, Sha256Update, Sha256Final},
65 { L"SHA384", 48, &mHashOidValue[23], 9, Sha384GetContextSize, Sha384Init, Sha384Update, Sha384Final},
66 { L"SHA512", 64, &mHashOidValue[32], 9, Sha512GetContextSize, Sha512Init, Sha512Update, Sha512Final}
67 };
68
69 EFI_STRING mHashTypeStr;
70
71 /**
72 SecureBoot Hook for processing image verification.
73
74 @param[in] VariableName Name of Variable to be found.
75 @param[in] VendorGuid Variable vendor GUID.
76 @param[in] DataSize Size of Data found. If size is less than the
77 data, this value contains the required size.
78 @param[in] Data Data pointer.
79
80 **/
81 VOID
82 EFIAPI
83 SecureBootHook (
84 IN CHAR16 *VariableName,
85 IN EFI_GUID *VendorGuid,
86 IN UINTN DataSize,
87 IN VOID *Data
88 );
89
90 /**
91 Reads contents of a PE/COFF image in memory buffer.
92
93 Caution: This function may receive untrusted input.
94 PE/COFF image is external input, so this function will make sure the PE/COFF image content
95 read is within the image buffer.
96
97 @param FileHandle Pointer to the file handle to read the PE/COFF image.
98 @param FileOffset Offset into the PE/COFF image to begin the read operation.
99 @param ReadSize On input, the size in bytes of the requested read operation.
100 On output, the number of bytes actually read.
101 @param Buffer Output buffer that contains the data read from the PE/COFF image.
102
103 @retval EFI_SUCCESS The specified portion of the PE/COFF image was read and the size
104 **/
105 EFI_STATUS
106 EFIAPI
107 DxeImageVerificationLibImageRead (
108 IN VOID *FileHandle,
109 IN UINTN FileOffset,
110 IN OUT UINTN *ReadSize,
111 OUT VOID *Buffer
112 )
113 {
114 UINTN EndPosition;
115
116 if (FileHandle == NULL || ReadSize == NULL || Buffer == NULL) {
117 return EFI_INVALID_PARAMETER;
118 }
119
120 if (MAX_ADDRESS - FileOffset < *ReadSize) {
121 return EFI_INVALID_PARAMETER;
122 }
123
124 EndPosition = FileOffset + *ReadSize;
125 if (EndPosition > mImageSize) {
126 *ReadSize = (UINT32)(mImageSize - FileOffset);
127 }
128
129 if (FileOffset >= mImageSize) {
130 *ReadSize = 0;
131 }
132
133 CopyMem (Buffer, (UINT8 *)((UINTN) FileHandle + FileOffset), *ReadSize);
134
135 return EFI_SUCCESS;
136 }
137
138
139 /**
140 Get the image type.
141
142 @param[in] File This is a pointer to the device path of the file that is
143 being dispatched.
144
145 @return UINT32 Image Type
146
147 **/
148 UINT32
149 GetImageType (
150 IN CONST EFI_DEVICE_PATH_PROTOCOL *File
151 )
152 {
153 EFI_STATUS Status;
154 EFI_HANDLE DeviceHandle;
155 EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;
156 EFI_BLOCK_IO_PROTOCOL *BlockIo;
157
158 if (File == NULL) {
159 return IMAGE_UNKNOWN;
160 }
161
162 //
163 // First check to see if File is from a Firmware Volume
164 //
165 DeviceHandle = NULL;
166 TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *) File;
167 Status = gBS->LocateDevicePath (
168 &gEfiFirmwareVolume2ProtocolGuid,
169 &TempDevicePath,
170 &DeviceHandle
171 );
172 if (!EFI_ERROR (Status)) {
173 Status = gBS->OpenProtocol (
174 DeviceHandle,
175 &gEfiFirmwareVolume2ProtocolGuid,
176 NULL,
177 NULL,
178 NULL,
179 EFI_OPEN_PROTOCOL_TEST_PROTOCOL
180 );
181 if (!EFI_ERROR (Status)) {
182 return IMAGE_FROM_FV;
183 }
184 }
185
186 //
187 // Next check to see if File is from a Block I/O device
188 //
189 DeviceHandle = NULL;
190 TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *) File;
191 Status = gBS->LocateDevicePath (
192 &gEfiBlockIoProtocolGuid,
193 &TempDevicePath,
194 &DeviceHandle
195 );
196 if (!EFI_ERROR (Status)) {
197 BlockIo = NULL;
198 Status = gBS->OpenProtocol (
199 DeviceHandle,
200 &gEfiBlockIoProtocolGuid,
201 (VOID **) &BlockIo,
202 NULL,
203 NULL,
204 EFI_OPEN_PROTOCOL_GET_PROTOCOL
205 );
206 if (!EFI_ERROR (Status) && BlockIo != NULL) {
207 if (BlockIo->Media != NULL) {
208 if (BlockIo->Media->RemovableMedia) {
209 //
210 // Block I/O is present and specifies the media is removable
211 //
212 return IMAGE_FROM_REMOVABLE_MEDIA;
213 } else {
214 //
215 // Block I/O is present and specifies the media is not removable
216 //
217 return IMAGE_FROM_FIXED_MEDIA;
218 }
219 }
220 }
221 }
222
223 //
224 // File is not in a Firmware Volume or on a Block I/O device, so check to see if
225 // the device path supports the Simple File System Protocol.
226 //
227 DeviceHandle = NULL;
228 TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *) File;
229 Status = gBS->LocateDevicePath (
230 &gEfiSimpleFileSystemProtocolGuid,
231 &TempDevicePath,
232 &DeviceHandle
233 );
234 if (!EFI_ERROR (Status)) {
235 //
236 // Simple File System is present without Block I/O, so assume media is fixed.
237 //
238 return IMAGE_FROM_FIXED_MEDIA;
239 }
240
241 //
242 // File is not from an FV, Block I/O or Simple File System, so the only options
243 // left are a PCI Option ROM and a Load File Protocol such as a PXE Boot from a NIC.
244 //
245 TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *) File;
246 while (!IsDevicePathEndType (TempDevicePath)) {
247 switch (DevicePathType (TempDevicePath)) {
248
249 case MEDIA_DEVICE_PATH:
250 if (DevicePathSubType (TempDevicePath) == MEDIA_RELATIVE_OFFSET_RANGE_DP) {
251 return IMAGE_FROM_OPTION_ROM;
252 }
253 break;
254
255 case MESSAGING_DEVICE_PATH:
256 if (DevicePathSubType(TempDevicePath) == MSG_MAC_ADDR_DP) {
257 return IMAGE_FROM_REMOVABLE_MEDIA;
258 }
259 break;
260
261 default:
262 break;
263 }
264 TempDevicePath = NextDevicePathNode (TempDevicePath);
265 }
266 return IMAGE_UNKNOWN;
267 }
268
269 /**
270 Calculate hash of Pe/Coff image based on the authenticode image hashing in
271 PE/COFF Specification 8.0 Appendix A
272
273 Caution: This function may receive untrusted input.
274 PE/COFF image is external input, so this function will validate its data structure
275 within this image buffer before use.
276
277 Notes: PE/COFF image has been checked by BasePeCoffLib PeCoffLoaderGetImageInfo() in
278 its caller function DxeImageVerificationHandler().
279
280 @param[in] HashAlg Hash algorithm type.
281
282 @retval TRUE Successfully hash image.
283 @retval FALSE Fail in hash image.
284
285 **/
286 BOOLEAN
287 HashPeImage (
288 IN UINT32 HashAlg
289 )
290 {
291 BOOLEAN Status;
292 EFI_IMAGE_SECTION_HEADER *Section;
293 VOID *HashCtx;
294 UINTN CtxSize;
295 UINT8 *HashBase;
296 UINTN HashSize;
297 UINTN SumOfBytesHashed;
298 EFI_IMAGE_SECTION_HEADER *SectionHeader;
299 UINTN Index;
300 UINTN Pos;
301 UINT32 CertSize;
302 UINT32 NumberOfRvaAndSizes;
303
304 HashCtx = NULL;
305 SectionHeader = NULL;
306 Status = FALSE;
307
308 if ((HashAlg >= HASHALG_MAX)) {
309 return FALSE;
310 }
311
312 //
313 // Initialize context of hash.
314 //
315 ZeroMem (mImageDigest, MAX_DIGEST_SIZE);
316
317 switch (HashAlg) {
318 case HASHALG_SHA1:
319 mImageDigestSize = SHA1_DIGEST_SIZE;
320 mCertType = gEfiCertSha1Guid;
321 break;
322
323 case HASHALG_SHA256:
324 mImageDigestSize = SHA256_DIGEST_SIZE;
325 mCertType = gEfiCertSha256Guid;
326 break;
327
328 case HASHALG_SHA384:
329 mImageDigestSize = SHA384_DIGEST_SIZE;
330 mCertType = gEfiCertSha384Guid;
331 break;
332
333 case HASHALG_SHA512:
334 mImageDigestSize = SHA512_DIGEST_SIZE;
335 mCertType = gEfiCertSha512Guid;
336 break;
337
338 default:
339 return FALSE;
340 }
341
342 mHashTypeStr = mHash[HashAlg].Name;
343 CtxSize = mHash[HashAlg].GetContextSize();
344
345 HashCtx = AllocatePool (CtxSize);
346 if (HashCtx == NULL) {
347 return FALSE;
348 }
349
350 // 1. Load the image header into memory.
351
352 // 2. Initialize a SHA hash context.
353 Status = mHash[HashAlg].HashInit(HashCtx);
354
355 if (!Status) {
356 goto Done;
357 }
358
359 //
360 // Measuring PE/COFF Image Header;
361 // But CheckSum field and SECURITY data directory (certificate) are excluded
362 //
363
364 //
365 // 3. Calculate the distance from the base of the image header to the image checksum address.
366 // 4. Hash the image header from its base to beginning of the image checksum.
367 //
368 HashBase = mImageBase;
369 if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
370 //
371 // Use PE32 offset.
372 //
373 HashSize = (UINTN) (&mNtHeader.Pe32->OptionalHeader.CheckSum) - (UINTN) HashBase;
374 NumberOfRvaAndSizes = mNtHeader.Pe32->OptionalHeader.NumberOfRvaAndSizes;
375 } else if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
376 //
377 // Use PE32+ offset.
378 //
379 HashSize = (UINTN) (&mNtHeader.Pe32Plus->OptionalHeader.CheckSum) - (UINTN) HashBase;
380 NumberOfRvaAndSizes = mNtHeader.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes;
381 } else {
382 //
383 // Invalid header magic number.
384 //
385 Status = FALSE;
386 goto Done;
387 }
388
389 Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
390 if (!Status) {
391 goto Done;
392 }
393
394 //
395 // 5. Skip over the image checksum (it occupies a single ULONG).
396 //
397 if (NumberOfRvaAndSizes <= EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
398 //
399 // 6. Since there is no Cert Directory in optional header, hash everything
400 // from the end of the checksum to the end of image header.
401 //
402 if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
403 //
404 // Use PE32 offset.
405 //
406 HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.CheckSum + sizeof (UINT32);
407 HashSize = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders - ((UINTN) HashBase - (UINTN) mImageBase);
408 } else {
409 //
410 // Use PE32+ offset.
411 //
412 HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32);
413 HashSize = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders - ((UINTN) HashBase - (UINTN) mImageBase);
414 }
415
416 if (HashSize != 0) {
417 Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
418 if (!Status) {
419 goto Done;
420 }
421 }
422 } else {
423 //
424 // 7. Hash everything from the end of the checksum to the start of the Cert Directory.
425 //
426 if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
427 //
428 // Use PE32 offset.
429 //
430 HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.CheckSum + sizeof (UINT32);
431 HashSize = (UINTN) (&mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;
432 } else {
433 //
434 // Use PE32+ offset.
435 //
436 HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32);
437 HashSize = (UINTN) (&mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;
438 }
439
440 if (HashSize != 0) {
441 Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
442 if (!Status) {
443 goto Done;
444 }
445 }
446
447 //
448 // 8. Skip over the Cert Directory. (It is sizeof(IMAGE_DATA_DIRECTORY) bytes.)
449 // 9. Hash everything from the end of the Cert Directory to the end of image header.
450 //
451 if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
452 //
453 // Use PE32 offset
454 //
455 HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1];
456 HashSize = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders - ((UINTN) HashBase - (UINTN) mImageBase);
457 } else {
458 //
459 // Use PE32+ offset.
460 //
461 HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1];
462 HashSize = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders - ((UINTN) HashBase - (UINTN) mImageBase);
463 }
464
465 if (HashSize != 0) {
466 Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
467 if (!Status) {
468 goto Done;
469 }
470 }
471 }
472
473 //
474 // 10. Set the SUM_OF_BYTES_HASHED to the size of the header.
475 //
476 if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
477 //
478 // Use PE32 offset.
479 //
480 SumOfBytesHashed = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders;
481 } else {
482 //
483 // Use PE32+ offset
484 //
485 SumOfBytesHashed = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders;
486 }
487
488
489 Section = (EFI_IMAGE_SECTION_HEADER *) (
490 mImageBase +
491 mPeCoffHeaderOffset +
492 sizeof (UINT32) +
493 sizeof (EFI_IMAGE_FILE_HEADER) +
494 mNtHeader.Pe32->FileHeader.SizeOfOptionalHeader
495 );
496
497 //
498 // 11. Build a temporary table of pointers to all the IMAGE_SECTION_HEADER
499 // structures in the image. The 'NumberOfSections' field of the image
500 // header indicates how big the table should be. Do not include any
501 // IMAGE_SECTION_HEADERs in the table whose 'SizeOfRawData' field is zero.
502 //
503 SectionHeader = (EFI_IMAGE_SECTION_HEADER *) AllocateZeroPool (sizeof (EFI_IMAGE_SECTION_HEADER) * mNtHeader.Pe32->FileHeader.NumberOfSections);
504 if (SectionHeader == NULL) {
505 Status = FALSE;
506 goto Done;
507 }
508 //
509 // 12. Using the 'PointerToRawData' in the referenced section headers as
510 // a key, arrange the elements in the table in ascending order. In other
511 // words, sort the section headers according to the disk-file offset of
512 // the section.
513 //
514 for (Index = 0; Index < mNtHeader.Pe32->FileHeader.NumberOfSections; Index++) {
515 Pos = Index;
516 while ((Pos > 0) && (Section->PointerToRawData < SectionHeader[Pos - 1].PointerToRawData)) {
517 CopyMem (&SectionHeader[Pos], &SectionHeader[Pos - 1], sizeof (EFI_IMAGE_SECTION_HEADER));
518 Pos--;
519 }
520 CopyMem (&SectionHeader[Pos], Section, sizeof (EFI_IMAGE_SECTION_HEADER));
521 Section += 1;
522 }
523
524 //
525 // 13. Walk through the sorted table, bring the corresponding section
526 // into memory, and hash the entire section (using the 'SizeOfRawData'
527 // field in the section header to determine the amount of data to hash).
528 // 14. Add the section's 'SizeOfRawData' to SUM_OF_BYTES_HASHED .
529 // 15. Repeat steps 13 and 14 for all the sections in the sorted table.
530 //
531 for (Index = 0; Index < mNtHeader.Pe32->FileHeader.NumberOfSections; Index++) {
532 Section = &SectionHeader[Index];
533 if (Section->SizeOfRawData == 0) {
534 continue;
535 }
536 HashBase = mImageBase + Section->PointerToRawData;
537 HashSize = (UINTN) Section->SizeOfRawData;
538
539 Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
540 if (!Status) {
541 goto Done;
542 }
543
544 SumOfBytesHashed += HashSize;
545 }
546
547 //
548 // 16. If the file size is greater than SUM_OF_BYTES_HASHED, there is extra
549 // data in the file that needs to be added to the hash. This data begins
550 // at file offset SUM_OF_BYTES_HASHED and its length is:
551 // FileSize - (CertDirectory->Size)
552 //
553 if (mImageSize > SumOfBytesHashed) {
554 HashBase = mImageBase + SumOfBytesHashed;
555
556 if (NumberOfRvaAndSizes <= EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
557 CertSize = 0;
558 } else {
559 if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
560 //
561 // Use PE32 offset.
562 //
563 CertSize = mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY].Size;
564 } else {
565 //
566 // Use PE32+ offset.
567 //
568 CertSize = mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY].Size;
569 }
570 }
571
572 if (mImageSize > CertSize + SumOfBytesHashed) {
573 HashSize = (UINTN) (mImageSize - CertSize - SumOfBytesHashed);
574
575 Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
576 if (!Status) {
577 goto Done;
578 }
579 } else if (mImageSize < CertSize + SumOfBytesHashed) {
580 Status = FALSE;
581 goto Done;
582 }
583 }
584
585 Status = mHash[HashAlg].HashFinal(HashCtx, mImageDigest);
586
587 Done:
588 if (HashCtx != NULL) {
589 FreePool (HashCtx);
590 }
591 if (SectionHeader != NULL) {
592 FreePool (SectionHeader);
593 }
594 return Status;
595 }
596
597 /**
598 Recognize the Hash algorithm in PE/COFF Authenticode and calculate hash of
599 Pe/Coff image based on the authenticode image hashing in PE/COFF Specification
600 8.0 Appendix A
601
602 Caution: This function may receive untrusted input.
603 PE/COFF image is external input, so this function will validate its data structure
604 within this image buffer before use.
605
606 @param[in] AuthData Pointer to the Authenticode Signature retrieved from signed image.
607 @param[in] AuthDataSize Size of the Authenticode Signature in bytes.
608
609 @retval EFI_UNSUPPORTED Hash algorithm is not supported.
610 @retval EFI_SUCCESS Hash successfully.
611
612 **/
613 EFI_STATUS
614 HashPeImageByType (
615 IN UINT8 *AuthData,
616 IN UINTN AuthDataSize
617 )
618 {
619 UINT8 Index;
620
621 for (Index = 0; Index < HASHALG_MAX; Index++) {
622 //
623 // Check the Hash algorithm in PE/COFF Authenticode.
624 // According to PKCS#7 Definition:
625 // SignedData ::= SEQUENCE {
626 // version Version,
627 // digestAlgorithms DigestAlgorithmIdentifiers,
628 // contentInfo ContentInfo,
629 // .... }
630 // The DigestAlgorithmIdentifiers can be used to determine the hash algorithm in PE/COFF hashing
631 // This field has the fixed offset (+32) in final Authenticode ASN.1 data.
632 // Fixed offset (+32) is calculated based on two bytes of length encoding.
633 //
634 if ((*(AuthData + 1) & TWO_BYTE_ENCODE) != TWO_BYTE_ENCODE) {
635 //
636 // Only support two bytes of Long Form of Length Encoding.
637 //
638 continue;
639 }
640
641 if (AuthDataSize < 32 + mHash[Index].OidLength) {
642 return EFI_UNSUPPORTED;
643 }
644
645 if (CompareMem (AuthData + 32, mHash[Index].OidValue, mHash[Index].OidLength) == 0) {
646 break;
647 }
648 }
649
650 if (Index == HASHALG_MAX) {
651 return EFI_UNSUPPORTED;
652 }
653
654 //
655 // HASH PE Image based on Hash algorithm in PE/COFF Authenticode.
656 //
657 if (!HashPeImage(Index)) {
658 return EFI_UNSUPPORTED;
659 }
660
661 return EFI_SUCCESS;
662 }
663
664
665 /**
666 Returns the size of a given image execution info table in bytes.
667
668 This function returns the size, in bytes, of the image execution info table specified by
669 ImageExeInfoTable. If ImageExeInfoTable is NULL, then 0 is returned.
670
671 @param ImageExeInfoTable A pointer to a image execution info table structure.
672
673 @retval 0 If ImageExeInfoTable is NULL.
674 @retval Others The size of a image execution info table in bytes.
675
676 **/
677 UINTN
678 GetImageExeInfoTableSize (
679 EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable
680 )
681 {
682 UINTN Index;
683 EFI_IMAGE_EXECUTION_INFO *ImageExeInfoItem;
684 UINTN TotalSize;
685
686 if (ImageExeInfoTable == NULL) {
687 return 0;
688 }
689
690 ImageExeInfoItem = (EFI_IMAGE_EXECUTION_INFO *) ((UINT8 *) ImageExeInfoTable + sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE));
691 TotalSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE);
692 for (Index = 0; Index < ImageExeInfoTable->NumberOfImages; Index++) {
693 TotalSize += ReadUnaligned32 ((UINT32 *) &ImageExeInfoItem->InfoSize);
694 ImageExeInfoItem = (EFI_IMAGE_EXECUTION_INFO *) ((UINT8 *) ImageExeInfoItem + ReadUnaligned32 ((UINT32 *) &ImageExeInfoItem->InfoSize));
695 }
696
697 return TotalSize;
698 }
699
700 /**
701 Create an Image Execution Information Table entry and add it to system configuration table.
702
703 @param[in] Action Describes the action taken by the firmware regarding this image.
704 @param[in] Name Input a null-terminated, user-friendly name.
705 @param[in] DevicePath Input device path pointer.
706 @param[in] Signature Input signature info in EFI_SIGNATURE_LIST data structure.
707 @param[in] SignatureSize Size of signature. Must be zero if Signature is NULL.
708
709 **/
710 VOID
711 AddImageExeInfo (
712 IN EFI_IMAGE_EXECUTION_ACTION Action,
713 IN CHAR16 *Name OPTIONAL,
714 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
715 IN EFI_SIGNATURE_LIST *Signature OPTIONAL,
716 IN UINTN SignatureSize
717 )
718 {
719 EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable;
720 EFI_IMAGE_EXECUTION_INFO_TABLE *NewImageExeInfoTable;
721 EFI_IMAGE_EXECUTION_INFO *ImageExeInfoEntry;
722 UINTN ImageExeInfoTableSize;
723 UINTN NewImageExeInfoEntrySize;
724 UINTN NameStringLen;
725 UINTN DevicePathSize;
726 CHAR16 *NameStr;
727
728 ImageExeInfoTable = NULL;
729 NewImageExeInfoTable = NULL;
730 ImageExeInfoEntry = NULL;
731 NameStringLen = 0;
732 NameStr = NULL;
733
734 if (DevicePath == NULL) {
735 return ;
736 }
737
738 if (Name != NULL) {
739 NameStringLen = StrSize (Name);
740 } else {
741 NameStringLen = sizeof (CHAR16);
742 }
743
744 EfiGetSystemConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID **) &ImageExeInfoTable);
745 if (ImageExeInfoTable != NULL) {
746 //
747 // The table has been found!
748 // We must enlarge the table to accommodate the new exe info entry.
749 //
750 ImageExeInfoTableSize = GetImageExeInfoTableSize (ImageExeInfoTable);
751 } else {
752 //
753 // Not Found!
754 // We should create a new table to append to the configuration table.
755 //
756 ImageExeInfoTableSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE);
757 }
758
759 DevicePathSize = GetDevicePathSize (DevicePath);
760
761 //
762 // Signature size can be odd. Pad after signature to ensure next EXECUTION_INFO entry align
763 //
764 ASSERT (Signature != NULL || SignatureSize == 0);
765 NewImageExeInfoEntrySize = sizeof (EFI_IMAGE_EXECUTION_INFO) + NameStringLen + DevicePathSize + SignatureSize;
766
767 NewImageExeInfoTable = (EFI_IMAGE_EXECUTION_INFO_TABLE *) AllocateRuntimePool (ImageExeInfoTableSize + NewImageExeInfoEntrySize);
768 if (NewImageExeInfoTable == NULL) {
769 return ;
770 }
771
772 if (ImageExeInfoTable != NULL) {
773 CopyMem (NewImageExeInfoTable, ImageExeInfoTable, ImageExeInfoTableSize);
774 } else {
775 NewImageExeInfoTable->NumberOfImages = 0;
776 }
777 NewImageExeInfoTable->NumberOfImages++;
778 ImageExeInfoEntry = (EFI_IMAGE_EXECUTION_INFO *) ((UINT8 *) NewImageExeInfoTable + ImageExeInfoTableSize);
779 //
780 // Update new item's information.
781 //
782 WriteUnaligned32 ((UINT32 *) ImageExeInfoEntry, Action);
783 WriteUnaligned32 ((UINT32 *) ((UINT8 *) ImageExeInfoEntry + sizeof (EFI_IMAGE_EXECUTION_ACTION)), (UINT32) NewImageExeInfoEntrySize);
784
785 NameStr = (CHAR16 *)(ImageExeInfoEntry + 1);
786 if (Name != NULL) {
787 CopyMem ((UINT8 *) NameStr, Name, NameStringLen);
788 } else {
789 ZeroMem ((UINT8 *) NameStr, sizeof (CHAR16));
790 }
791
792 CopyMem (
793 (UINT8 *) NameStr + NameStringLen,
794 DevicePath,
795 DevicePathSize
796 );
797 if (Signature != NULL) {
798 CopyMem (
799 (UINT8 *) NameStr + NameStringLen + DevicePathSize,
800 Signature,
801 SignatureSize
802 );
803 }
804 //
805 // Update/replace the image execution table.
806 //
807 gBS->InstallConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID *) NewImageExeInfoTable);
808
809 //
810 // Free Old table data!
811 //
812 if (ImageExeInfoTable != NULL) {
813 FreePool (ImageExeInfoTable);
814 }
815 }
816
817 /**
818 Check whether the hash of an given X.509 certificate is in forbidden database (DBX).
819
820 @param[in] Certificate Pointer to X.509 Certificate that is searched for.
821 @param[in] CertSize Size of X.509 Certificate.
822 @param[in] SignatureList Pointer to the Signature List in forbidden database.
823 @param[in] SignatureListSize Size of Signature List.
824 @param[out] RevocationTime Return the time that the certificate was revoked.
825 @param[out] IsFound Search result. Only valid if EFI_SUCCESS returned.
826
827 @retval EFI_SUCCESS Finished the search without any error.
828 @retval Others Error occurred in the search of database.
829
830 **/
831 EFI_STATUS
832 IsCertHashFoundInDatabase (
833 IN UINT8 *Certificate,
834 IN UINTN CertSize,
835 IN EFI_SIGNATURE_LIST *SignatureList,
836 IN UINTN SignatureListSize,
837 OUT EFI_TIME *RevocationTime,
838 OUT BOOLEAN *IsFound
839 )
840 {
841 EFI_STATUS Status;
842 EFI_SIGNATURE_LIST *DbxList;
843 UINTN DbxSize;
844 EFI_SIGNATURE_DATA *CertHash;
845 UINTN CertHashCount;
846 UINTN Index;
847 UINT32 HashAlg;
848 VOID *HashCtx;
849 UINT8 CertDigest[MAX_DIGEST_SIZE];
850 UINT8 *DbxCertHash;
851 UINTN SiglistHeaderSize;
852 UINT8 *TBSCert;
853 UINTN TBSCertSize;
854
855 Status = EFI_ABORTED;
856 *IsFound = FALSE;
857 DbxList = SignatureList;
858 DbxSize = SignatureListSize;
859 HashCtx = NULL;
860 HashAlg = HASHALG_MAX;
861
862 if ((RevocationTime == NULL) || (DbxList == NULL)) {
863 return EFI_INVALID_PARAMETER;
864 }
865
866 //
867 // Retrieve the TBSCertificate from the X.509 Certificate.
868 //
869 if (!X509GetTBSCert (Certificate, CertSize, &TBSCert, &TBSCertSize)) {
870 return Status;
871 }
872
873 while ((DbxSize > 0) && (SignatureListSize >= DbxList->SignatureListSize)) {
874 //
875 // Determine Hash Algorithm of Certificate in the forbidden database.
876 //
877 if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha256Guid)) {
878 HashAlg = HASHALG_SHA256;
879 } else if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha384Guid)) {
880 HashAlg = HASHALG_SHA384;
881 } else if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha512Guid)) {
882 HashAlg = HASHALG_SHA512;
883 } else {
884 DbxSize -= DbxList->SignatureListSize;
885 DbxList = (EFI_SIGNATURE_LIST *) ((UINT8 *) DbxList + DbxList->SignatureListSize);
886 continue;
887 }
888
889 //
890 // Calculate the hash value of current TBSCertificate for comparision.
891 //
892 if (mHash[HashAlg].GetContextSize == NULL) {
893 goto Done;
894 }
895 ZeroMem (CertDigest, MAX_DIGEST_SIZE);
896 HashCtx = AllocatePool (mHash[HashAlg].GetContextSize ());
897 if (HashCtx == NULL) {
898 goto Done;
899 }
900 if (!mHash[HashAlg].HashInit (HashCtx)) {
901 goto Done;
902 }
903 if (!mHash[HashAlg].HashUpdate (HashCtx, TBSCert, TBSCertSize)) {
904 goto Done;
905 }
906 if (!mHash[HashAlg].HashFinal (HashCtx, CertDigest)) {
907 goto Done;
908 }
909
910 FreePool (HashCtx);
911 HashCtx = NULL;
912
913 SiglistHeaderSize = sizeof (EFI_SIGNATURE_LIST) + DbxList->SignatureHeaderSize;
914 CertHash = (EFI_SIGNATURE_DATA *) ((UINT8 *) DbxList + SiglistHeaderSize);
915 CertHashCount = (DbxList->SignatureListSize - SiglistHeaderSize) / DbxList->SignatureSize;
916 for (Index = 0; Index < CertHashCount; Index++) {
917 //
918 // Iterate each Signature Data Node within this CertList for verify.
919 //
920 DbxCertHash = CertHash->SignatureData;
921 if (CompareMem (DbxCertHash, CertDigest, mHash[HashAlg].DigestLength) == 0) {
922 //
923 // Hash of Certificate is found in forbidden database.
924 //
925 Status = EFI_SUCCESS;
926 *IsFound = TRUE;
927
928 //
929 // Return the revocation time.
930 //
931 CopyMem (RevocationTime, (EFI_TIME *)(DbxCertHash + mHash[HashAlg].DigestLength), sizeof (EFI_TIME));
932 goto Done;
933 }
934 CertHash = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertHash + DbxList->SignatureSize);
935 }
936
937 DbxSize -= DbxList->SignatureListSize;
938 DbxList = (EFI_SIGNATURE_LIST *) ((UINT8 *) DbxList + DbxList->SignatureListSize);
939 }
940
941 Status = EFI_SUCCESS;
942
943 Done:
944 if (HashCtx != NULL) {
945 FreePool (HashCtx);
946 }
947
948 return Status;
949 }
950
951 /**
952 Check whether signature is in specified database.
953
954 @param[in] VariableName Name of database variable that is searched in.
955 @param[in] Signature Pointer to signature that is searched for.
956 @param[in] CertType Pointer to hash algorithm.
957 @param[in] SignatureSize Size of Signature.
958
959 @return TRUE Found the signature in the variable database.
960 @return FALSE Not found the signature in the variable database.
961
962 **/
963 BOOLEAN
964 IsSignatureFoundInDatabase (
965 IN CHAR16 *VariableName,
966 IN UINT8 *Signature,
967 IN EFI_GUID *CertType,
968 IN UINTN SignatureSize
969 )
970 {
971 EFI_STATUS Status;
972 EFI_SIGNATURE_LIST *CertList;
973 EFI_SIGNATURE_DATA *Cert;
974 UINTN DataSize;
975 UINT8 *Data;
976 UINTN Index;
977 UINTN CertCount;
978 BOOLEAN IsFound;
979
980 //
981 // Read signature database variable.
982 //
983 IsFound = FALSE;
984 Data = NULL;
985 DataSize = 0;
986 Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
987 if (Status != EFI_BUFFER_TOO_SMALL) {
988 return FALSE;
989 }
990
991 Data = (UINT8 *) AllocateZeroPool (DataSize);
992 if (Data == NULL) {
993 return FALSE;
994 }
995
996 Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, Data);
997 if (EFI_ERROR (Status)) {
998 goto Done;
999 }
1000 //
1001 // Enumerate all signature data in SigDB to check if signature exists for executable.
1002 //
1003 CertList = (EFI_SIGNATURE_LIST *) Data;
1004 while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
1005 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1006 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1007 if ((CertList->SignatureSize == sizeof(EFI_SIGNATURE_DATA) - 1 + SignatureSize) && (CompareGuid(&CertList->SignatureType, CertType))) {
1008 for (Index = 0; Index < CertCount; Index++) {
1009 if (CompareMem (Cert->SignatureData, Signature, SignatureSize) == 0) {
1010 //
1011 // Find the signature in database.
1012 //
1013 IsFound = TRUE;
1014 //
1015 // Entries in UEFI_IMAGE_SECURITY_DATABASE that are used to validate image should be measured
1016 //
1017 if (StrCmp(VariableName, EFI_IMAGE_SECURITY_DATABASE) == 0) {
1018 SecureBootHook (VariableName, &gEfiImageSecurityDatabaseGuid, CertList->SignatureSize, Cert);
1019 }
1020 break;
1021 }
1022
1023 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
1024 }
1025
1026 if (IsFound) {
1027 break;
1028 }
1029 }
1030
1031 DataSize -= CertList->SignatureListSize;
1032 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1033 }
1034
1035 Done:
1036 if (Data != NULL) {
1037 FreePool (Data);
1038 }
1039
1040 return IsFound;
1041 }
1042
1043 /**
1044 Check whether the timestamp is valid by comparing the signing time and the revocation time.
1045
1046 @param SigningTime A pointer to the signing time.
1047 @param RevocationTime A pointer to the revocation time.
1048
1049 @retval TRUE The SigningTime is not later than the RevocationTime.
1050 @retval FALSE The SigningTime is later than the RevocationTime.
1051
1052 **/
1053 BOOLEAN
1054 IsValidSignatureByTimestamp (
1055 IN EFI_TIME *SigningTime,
1056 IN EFI_TIME *RevocationTime
1057 )
1058 {
1059 if (SigningTime->Year != RevocationTime->Year) {
1060 return (BOOLEAN) (SigningTime->Year < RevocationTime->Year);
1061 } else if (SigningTime->Month != RevocationTime->Month) {
1062 return (BOOLEAN) (SigningTime->Month < RevocationTime->Month);
1063 } else if (SigningTime->Day != RevocationTime->Day) {
1064 return (BOOLEAN) (SigningTime->Day < RevocationTime->Day);
1065 } else if (SigningTime->Hour != RevocationTime->Hour) {
1066 return (BOOLEAN) (SigningTime->Hour < RevocationTime->Hour);
1067 } else if (SigningTime->Minute != RevocationTime->Minute) {
1068 return (BOOLEAN) (SigningTime->Minute < RevocationTime->Minute);
1069 }
1070
1071 return (BOOLEAN) (SigningTime->Second <= RevocationTime->Second);
1072 }
1073
1074 /**
1075 Check if the given time value is zero.
1076
1077 @param[in] Time Pointer of a time value.
1078
1079 @retval TRUE The Time is Zero.
1080 @retval FALSE The Time is not Zero.
1081
1082 **/
1083 BOOLEAN
1084 IsTimeZero (
1085 IN EFI_TIME *Time
1086 )
1087 {
1088 if ((Time->Year == 0) && (Time->Month == 0) && (Time->Day == 0) &&
1089 (Time->Hour == 0) && (Time->Minute == 0) && (Time->Second == 0)) {
1090 return TRUE;
1091 }
1092
1093 return FALSE;
1094 }
1095
1096 /**
1097 Check whether the timestamp signature is valid and the signing time is also earlier than
1098 the revocation time.
1099
1100 @param[in] AuthData Pointer to the Authenticode signature retrieved from signed image.
1101 @param[in] AuthDataSize Size of the Authenticode signature in bytes.
1102 @param[in] RevocationTime The time that the certificate was revoked.
1103
1104 @retval TRUE Timestamp signature is valid and signing time is no later than the
1105 revocation time.
1106 @retval FALSE Timestamp signature is not valid or the signing time is later than the
1107 revocation time.
1108
1109 **/
1110 BOOLEAN
1111 PassTimestampCheck (
1112 IN UINT8 *AuthData,
1113 IN UINTN AuthDataSize,
1114 IN EFI_TIME *RevocationTime
1115 )
1116 {
1117 EFI_STATUS Status;
1118 BOOLEAN VerifyStatus;
1119 EFI_SIGNATURE_LIST *CertList;
1120 EFI_SIGNATURE_DATA *Cert;
1121 UINT8 *DbtData;
1122 UINTN DbtDataSize;
1123 UINT8 *RootCert;
1124 UINTN RootCertSize;
1125 UINTN Index;
1126 UINTN CertCount;
1127 EFI_TIME SigningTime;
1128
1129 //
1130 // Variable Initialization
1131 //
1132 VerifyStatus = FALSE;
1133 DbtData = NULL;
1134 CertList = NULL;
1135 Cert = NULL;
1136 RootCert = NULL;
1137 RootCertSize = 0;
1138
1139 //
1140 // If RevocationTime is zero, the certificate shall be considered to always be revoked.
1141 //
1142 if (IsTimeZero (RevocationTime)) {
1143 return FALSE;
1144 }
1145
1146 //
1147 // RevocationTime is non-zero, the certificate should be considered to be revoked from that time and onwards.
1148 // Using the dbt to get the trusted TSA certificates.
1149 //
1150 DbtDataSize = 0;
1151 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE2, &gEfiImageSecurityDatabaseGuid, NULL, &DbtDataSize, NULL);
1152 if (Status != EFI_BUFFER_TOO_SMALL) {
1153 goto Done;
1154 }
1155 DbtData = (UINT8 *) AllocateZeroPool (DbtDataSize);
1156 if (DbtData == NULL) {
1157 goto Done;
1158 }
1159 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE2, &gEfiImageSecurityDatabaseGuid, NULL, &DbtDataSize, (VOID *) DbtData);
1160 if (EFI_ERROR (Status)) {
1161 goto Done;
1162 }
1163
1164 CertList = (EFI_SIGNATURE_LIST *) DbtData;
1165 while ((DbtDataSize > 0) && (DbtDataSize >= CertList->SignatureListSize)) {
1166 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
1167 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1168 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1169 for (Index = 0; Index < CertCount; Index++) {
1170 //
1171 // Iterate each Signature Data Node within this CertList for verify.
1172 //
1173 RootCert = Cert->SignatureData;
1174 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
1175 //
1176 // Get the signing time if the timestamp signature is valid.
1177 //
1178 if (ImageTimestampVerify (AuthData, AuthDataSize, RootCert, RootCertSize, &SigningTime)) {
1179 //
1180 // The signer signature is valid only when the signing time is earlier than revocation time.
1181 //
1182 if (IsValidSignatureByTimestamp (&SigningTime, RevocationTime)) {
1183 VerifyStatus = TRUE;
1184 goto Done;
1185 }
1186 }
1187 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
1188 }
1189 }
1190 DbtDataSize -= CertList->SignatureListSize;
1191 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1192 }
1193
1194 Done:
1195 if (DbtData != NULL) {
1196 FreePool (DbtData);
1197 }
1198
1199 return VerifyStatus;
1200 }
1201
1202 /**
1203 Check whether the image signature is forbidden by the forbidden database (dbx).
1204 The image is forbidden to load if any certificates for signing are revoked before signing time.
1205
1206 @param[in] AuthData Pointer to the Authenticode signature retrieved from the signed image.
1207 @param[in] AuthDataSize Size of the Authenticode signature in bytes.
1208
1209 @retval TRUE Image is forbidden by dbx.
1210 @retval FALSE Image is not forbidden by dbx.
1211
1212 **/
1213 BOOLEAN
1214 IsForbiddenByDbx (
1215 IN UINT8 *AuthData,
1216 IN UINTN AuthDataSize
1217 )
1218 {
1219 EFI_STATUS Status;
1220 BOOLEAN IsForbidden;
1221 BOOLEAN IsFound;
1222 UINT8 *Data;
1223 UINTN DataSize;
1224 EFI_SIGNATURE_LIST *CertList;
1225 UINTN CertListSize;
1226 EFI_SIGNATURE_DATA *CertData;
1227 UINT8 *RootCert;
1228 UINTN RootCertSize;
1229 UINTN CertCount;
1230 UINTN Index;
1231 UINT8 *CertBuffer;
1232 UINTN BufferLength;
1233 UINT8 *TrustedCert;
1234 UINTN TrustedCertLength;
1235 UINT8 CertNumber;
1236 UINT8 *CertPtr;
1237 UINT8 *Cert;
1238 UINTN CertSize;
1239 EFI_TIME RevocationTime;
1240 //
1241 // Variable Initialization
1242 //
1243 IsForbidden = FALSE;
1244 Data = NULL;
1245 CertList = NULL;
1246 CertData = NULL;
1247 RootCert = NULL;
1248 RootCertSize = 0;
1249 Cert = NULL;
1250 CertBuffer = NULL;
1251 BufferLength = 0;
1252 TrustedCert = NULL;
1253 TrustedCertLength = 0;
1254
1255 //
1256 // The image will not be forbidden if dbx can't be got.
1257 //
1258 DataSize = 0;
1259 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
1260 if (Status != EFI_BUFFER_TOO_SMALL) {
1261 return IsForbidden;
1262 }
1263 Data = (UINT8 *) AllocateZeroPool (DataSize);
1264 if (Data == NULL) {
1265 return IsForbidden;
1266 }
1267
1268 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data);
1269 if (EFI_ERROR (Status)) {
1270 return IsForbidden;
1271 }
1272
1273 //
1274 // Verify image signature with RAW X509 certificates in DBX database.
1275 // If passed, the image will be forbidden.
1276 //
1277 CertList = (EFI_SIGNATURE_LIST *) Data;
1278 CertListSize = DataSize;
1279 while ((CertListSize > 0) && (CertListSize >= CertList->SignatureListSize)) {
1280 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
1281 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1282 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1283
1284 for (Index = 0; Index < CertCount; Index++) {
1285 //
1286 // Iterate each Signature Data Node within this CertList for verify.
1287 //
1288 RootCert = CertData->SignatureData;
1289 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
1290
1291 //
1292 // Call AuthenticodeVerify library to Verify Authenticode struct.
1293 //
1294 IsForbidden = AuthenticodeVerify (
1295 AuthData,
1296 AuthDataSize,
1297 RootCert,
1298 RootCertSize,
1299 mImageDigest,
1300 mImageDigestSize
1301 );
1302 if (IsForbidden) {
1303 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature is forbidden by DBX.\n"));
1304 goto Done;
1305 }
1306
1307 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize);
1308 }
1309 }
1310
1311 CertListSize -= CertList->SignatureListSize;
1312 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1313 }
1314
1315 //
1316 // Check X.509 Certificate Hash & Possible Timestamp.
1317 //
1318
1319 //
1320 // Retrieve the certificate stack from AuthData
1321 // The output CertStack format will be:
1322 // UINT8 CertNumber;
1323 // UINT32 Cert1Length;
1324 // UINT8 Cert1[];
1325 // UINT32 Cert2Length;
1326 // UINT8 Cert2[];
1327 // ...
1328 // UINT32 CertnLength;
1329 // UINT8 Certn[];
1330 //
1331 Pkcs7GetSigners (AuthData, AuthDataSize, &CertBuffer, &BufferLength, &TrustedCert, &TrustedCertLength);
1332 if ((BufferLength == 0) || (CertBuffer == NULL) || (*CertBuffer) == 0) {
1333 IsForbidden = TRUE;
1334 goto Done;
1335 }
1336
1337 //
1338 // Check if any hash of certificates embedded in AuthData is in the forbidden database.
1339 //
1340 CertNumber = (UINT8) (*CertBuffer);
1341 CertPtr = CertBuffer + 1;
1342 for (Index = 0; Index < CertNumber; Index++) {
1343 CertSize = (UINTN) ReadUnaligned32 ((UINT32 *)CertPtr);
1344 Cert = (UINT8 *)CertPtr + sizeof (UINT32);
1345 //
1346 // Advance CertPtr to the next cert in image signer's cert list
1347 //
1348 CertPtr = CertPtr + sizeof (UINT32) + CertSize;
1349
1350 Status = IsCertHashFoundInDatabase (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data, DataSize, &RevocationTime, &IsFound);
1351 if (EFI_ERROR (Status)) {
1352 //
1353 // Error in searching dbx. Consider it as 'found'. RevocationTime might
1354 // not be valid in such situation.
1355 //
1356 IsForbidden = TRUE;
1357 } else if (IsFound) {
1358 //
1359 // Found Cert in dbx successfully. Check the timestamp signature and
1360 // signing time to determine if the image can be trusted.
1361 //
1362 if (PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime)) {
1363 IsForbidden = FALSE;
1364 //
1365 // Pass DBT check. Continue to check other certs in image signer's cert list against DBX, DBT
1366 //
1367 continue;
1368 } else {
1369 IsForbidden = TRUE;
1370 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature failed the timestamp check.\n"));
1371 goto Done;
1372 }
1373 }
1374
1375 }
1376
1377 Done:
1378 if (Data != NULL) {
1379 FreePool (Data);
1380 }
1381
1382 Pkcs7FreeSigners (CertBuffer);
1383 Pkcs7FreeSigners (TrustedCert);
1384
1385 return IsForbidden;
1386 }
1387
1388
1389 /**
1390 Check whether the image signature can be verified by the trusted certificates in DB database.
1391
1392 @param[in] AuthData Pointer to the Authenticode signature retrieved from signed image.
1393 @param[in] AuthDataSize Size of the Authenticode signature in bytes.
1394
1395 @retval TRUE Image passed verification using certificate in db.
1396 @retval FALSE Image didn't pass verification using certificate in db.
1397
1398 **/
1399 BOOLEAN
1400 IsAllowedByDb (
1401 IN UINT8 *AuthData,
1402 IN UINTN AuthDataSize
1403 )
1404 {
1405 EFI_STATUS Status;
1406 BOOLEAN VerifyStatus;
1407 BOOLEAN IsFound;
1408 EFI_SIGNATURE_LIST *CertList;
1409 EFI_SIGNATURE_DATA *CertData;
1410 UINTN DataSize;
1411 UINT8 *Data;
1412 UINT8 *RootCert;
1413 UINTN RootCertSize;
1414 UINTN Index;
1415 UINTN CertCount;
1416 UINTN DbxDataSize;
1417 UINT8 *DbxData;
1418 EFI_TIME RevocationTime;
1419
1420 Data = NULL;
1421 CertList = NULL;
1422 CertData = NULL;
1423 RootCert = NULL;
1424 DbxData = NULL;
1425 RootCertSize = 0;
1426 VerifyStatus = FALSE;
1427
1428 //
1429 // Fetch 'db' content. If 'db' doesn't exist or encounters problem to get the
1430 // data, return not-allowed-by-db (FALSE).
1431 //
1432 DataSize = 0;
1433 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
1434 ASSERT (EFI_ERROR (Status));
1435 if (Status != EFI_BUFFER_TOO_SMALL) {
1436 return VerifyStatus;
1437 }
1438
1439 Data = (UINT8 *) AllocateZeroPool (DataSize);
1440 if (Data == NULL) {
1441 return VerifyStatus;
1442 }
1443
1444 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data);
1445 if (EFI_ERROR (Status)) {
1446 goto Done;
1447 }
1448
1449 //
1450 // Fetch 'dbx' content. If 'dbx' doesn't exist, continue to check 'db'.
1451 // If any other errors occured, no need to check 'db' but just return
1452 // not-allowed-by-db (FALSE) to avoid bypass.
1453 //
1454 DbxDataSize = 0;
1455 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, NULL);
1456 ASSERT (EFI_ERROR (Status));
1457 if (Status != EFI_BUFFER_TOO_SMALL) {
1458 if (Status != EFI_NOT_FOUND) {
1459 goto Done;
1460 }
1461 //
1462 // 'dbx' does not exist. Continue to check 'db'.
1463 //
1464 } else {
1465 //
1466 // 'dbx' exists. Get its content.
1467 //
1468 DbxData = (UINT8 *) AllocateZeroPool (DbxDataSize);
1469 if (DbxData == NULL) {
1470 goto Done;
1471 }
1472
1473 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, (VOID *) DbxData);
1474 if (EFI_ERROR (Status)) {
1475 goto Done;
1476 }
1477 }
1478
1479 //
1480 // Find X509 certificate in Signature List to verify the signature in pkcs7 signed data.
1481 //
1482 CertList = (EFI_SIGNATURE_LIST *) Data;
1483 while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
1484 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
1485 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1486 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1487
1488 for (Index = 0; Index < CertCount; Index++) {
1489 //
1490 // Iterate each Signature Data Node within this CertList for verify.
1491 //
1492 RootCert = CertData->SignatureData;
1493 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
1494
1495 //
1496 // Call AuthenticodeVerify library to Verify Authenticode struct.
1497 //
1498 VerifyStatus = AuthenticodeVerify (
1499 AuthData,
1500 AuthDataSize,
1501 RootCert,
1502 RootCertSize,
1503 mImageDigest,
1504 mImageDigestSize
1505 );
1506 if (VerifyStatus) {
1507 //
1508 // The image is signed and its signature is found in 'db'.
1509 //
1510 if (DbxData != NULL) {
1511 //
1512 // Here We still need to check if this RootCert's Hash is revoked
1513 //
1514 Status = IsCertHashFoundInDatabase (RootCert, RootCertSize, (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime, &IsFound);
1515 if (EFI_ERROR (Status)) {
1516 //
1517 // Error in searching dbx. Consider it as 'found'. RevocationTime might
1518 // not be valid in such situation.
1519 //
1520 VerifyStatus = FALSE;
1521 } else if (IsFound) {
1522 //
1523 // Check the timestamp signature and signing time to determine if the RootCert can be trusted.
1524 //
1525 VerifyStatus = PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime);
1526 if (!VerifyStatus) {
1527 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed and signature is accepted by DB, but its root cert failed the timestamp check.\n"));
1528 }
1529 }
1530 }
1531
1532 //
1533 // There's no 'dbx' to check revocation time against (must-be pass),
1534 // or, there's revocation time found in 'dbx' and checked againt 'dbt'
1535 // (maybe pass or fail, depending on timestamp compare result). Either
1536 // way the verification job has been completed at this point.
1537 //
1538 goto Done;
1539 }
1540
1541 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize);
1542 }
1543 }
1544
1545 DataSize -= CertList->SignatureListSize;
1546 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1547 }
1548
1549 Done:
1550
1551 if (VerifyStatus) {
1552 SecureBootHook (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, CertList->SignatureSize, CertData);
1553 }
1554
1555 if (Data != NULL) {
1556 FreePool (Data);
1557 }
1558 if (DbxData != NULL) {
1559 FreePool (DbxData);
1560 }
1561
1562 return VerifyStatus;
1563 }
1564
1565 /**
1566 Provide verification service for signed images, which include both signature validation
1567 and platform policy control. For signature types, both UEFI WIN_CERTIFICATE_UEFI_GUID and
1568 MSFT Authenticode type signatures are supported.
1569
1570 In this implementation, only verify external executables when in USER MODE.
1571 Executables from FV is bypass, so pass in AuthenticationStatus is ignored.
1572
1573 The image verification policy is:
1574 If the image is signed,
1575 At least one valid signature or at least one hash value of the image must match a record
1576 in the security database "db", and no valid signature nor any hash value of the image may
1577 be reflected in the security database "dbx".
1578 Otherwise, the image is not signed,
1579 The SHA256 hash value of the image must match a record in the security database "db", and
1580 not be reflected in the security data base "dbx".
1581
1582 Caution: This function may receive untrusted input.
1583 PE/COFF image is external input, so this function will validate its data structure
1584 within this image buffer before use.
1585
1586 @param[in] AuthenticationStatus
1587 This is the authentication status returned from the security
1588 measurement services for the input file.
1589 @param[in] File This is a pointer to the device path of the file that is
1590 being dispatched. This will optionally be used for logging.
1591 @param[in] FileBuffer File buffer matches the input file device path.
1592 @param[in] FileSize Size of File buffer matches the input file device path.
1593 @param[in] BootPolicy A boot policy that was used to call LoadImage() UEFI service.
1594
1595 @retval EFI_SUCCESS The file specified by DevicePath and non-NULL
1596 FileBuffer did authenticate, and the platform policy dictates
1597 that the DXE Foundation may use the file.
1598 @retval EFI_SUCCESS The device path specified by NULL device path DevicePath
1599 and non-NULL FileBuffer did authenticate, and the platform
1600 policy dictates that the DXE Foundation may execute the image in
1601 FileBuffer.
1602 @retval EFI_SECURITY_VIOLATION The file specified by File did not authenticate, and
1603 the platform policy dictates that File should be placed
1604 in the untrusted state. The image has been added to the file
1605 execution table.
1606 @retval EFI_ACCESS_DENIED The file specified by File and FileBuffer did not
1607 authenticate, and the platform policy dictates that the DXE
1608 Foundation may not use File. The image has
1609 been added to the file execution table.
1610
1611 **/
1612 EFI_STATUS
1613 EFIAPI
1614 DxeImageVerificationHandler (
1615 IN UINT32 AuthenticationStatus,
1616 IN CONST EFI_DEVICE_PATH_PROTOCOL *File,
1617 IN VOID *FileBuffer,
1618 IN UINTN FileSize,
1619 IN BOOLEAN BootPolicy
1620 )
1621 {
1622 EFI_IMAGE_DOS_HEADER *DosHdr;
1623 BOOLEAN IsVerified;
1624 EFI_SIGNATURE_LIST *SignatureList;
1625 UINTN SignatureListSize;
1626 EFI_SIGNATURE_DATA *Signature;
1627 EFI_IMAGE_EXECUTION_ACTION Action;
1628 WIN_CERTIFICATE *WinCertificate;
1629 UINT32 Policy;
1630 UINT8 *SecureBoot;
1631 PE_COFF_LOADER_IMAGE_CONTEXT ImageContext;
1632 UINT32 NumberOfRvaAndSizes;
1633 WIN_CERTIFICATE_EFI_PKCS *PkcsCertData;
1634 WIN_CERTIFICATE_UEFI_GUID *WinCertUefiGuid;
1635 UINT8 *AuthData;
1636 UINTN AuthDataSize;
1637 EFI_IMAGE_DATA_DIRECTORY *SecDataDir;
1638 UINT32 OffSet;
1639 CHAR16 *NameStr;
1640 RETURN_STATUS PeCoffStatus;
1641 EFI_STATUS HashStatus;
1642
1643 SignatureList = NULL;
1644 SignatureListSize = 0;
1645 WinCertificate = NULL;
1646 SecDataDir = NULL;
1647 PkcsCertData = NULL;
1648 Action = EFI_IMAGE_EXECUTION_AUTH_UNTESTED;
1649 IsVerified = FALSE;
1650
1651
1652 //
1653 // Check the image type and get policy setting.
1654 //
1655 switch (GetImageType (File)) {
1656
1657 case IMAGE_FROM_FV:
1658 Policy = ALWAYS_EXECUTE;
1659 break;
1660
1661 case IMAGE_FROM_OPTION_ROM:
1662 Policy = PcdGet32 (PcdOptionRomImageVerificationPolicy);
1663 break;
1664
1665 case IMAGE_FROM_REMOVABLE_MEDIA:
1666 Policy = PcdGet32 (PcdRemovableMediaImageVerificationPolicy);
1667 break;
1668
1669 case IMAGE_FROM_FIXED_MEDIA:
1670 Policy = PcdGet32 (PcdFixedMediaImageVerificationPolicy);
1671 break;
1672
1673 default:
1674 Policy = DENY_EXECUTE_ON_SECURITY_VIOLATION;
1675 break;
1676 }
1677 //
1678 // If policy is always/never execute, return directly.
1679 //
1680 if (Policy == ALWAYS_EXECUTE) {
1681 return EFI_SUCCESS;
1682 }
1683 if (Policy == NEVER_EXECUTE) {
1684 return EFI_ACCESS_DENIED;
1685 }
1686
1687 //
1688 // The policy QUERY_USER_ON_SECURITY_VIOLATION and ALLOW_EXECUTE_ON_SECURITY_VIOLATION
1689 // violates the UEFI spec and has been removed.
1690 //
1691 ASSERT (Policy != QUERY_USER_ON_SECURITY_VIOLATION && Policy != ALLOW_EXECUTE_ON_SECURITY_VIOLATION);
1692 if (Policy == QUERY_USER_ON_SECURITY_VIOLATION || Policy == ALLOW_EXECUTE_ON_SECURITY_VIOLATION) {
1693 CpuDeadLoop ();
1694 }
1695
1696 GetEfiGlobalVariable2 (EFI_SECURE_BOOT_MODE_NAME, (VOID**)&SecureBoot, NULL);
1697 //
1698 // Skip verification if SecureBoot variable doesn't exist.
1699 //
1700 if (SecureBoot == NULL) {
1701 return EFI_SUCCESS;
1702 }
1703
1704 //
1705 // Skip verification if SecureBoot is disabled but not AuditMode
1706 //
1707 if (*SecureBoot == SECURE_BOOT_MODE_DISABLE) {
1708 FreePool (SecureBoot);
1709 return EFI_SUCCESS;
1710 }
1711 FreePool (SecureBoot);
1712
1713 //
1714 // Read the Dos header.
1715 //
1716 if (FileBuffer == NULL) {
1717 return EFI_ACCESS_DENIED;
1718 }
1719
1720 mImageBase = (UINT8 *) FileBuffer;
1721 mImageSize = FileSize;
1722
1723 ZeroMem (&ImageContext, sizeof (ImageContext));
1724 ImageContext.Handle = (VOID *) FileBuffer;
1725 ImageContext.ImageRead = (PE_COFF_LOADER_READ_FILE) DxeImageVerificationLibImageRead;
1726
1727 //
1728 // Get information about the image being loaded
1729 //
1730 PeCoffStatus = PeCoffLoaderGetImageInfo (&ImageContext);
1731 if (RETURN_ERROR (PeCoffStatus)) {
1732 //
1733 // The information can't be got from the invalid PeImage
1734 //
1735 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: PeImage invalid. Cannot retrieve image information.\n"));
1736 goto Failed;
1737 }
1738
1739 DosHdr = (EFI_IMAGE_DOS_HEADER *) mImageBase;
1740 if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) {
1741 //
1742 // DOS image header is present,
1743 // so read the PE header after the DOS image header.
1744 //
1745 mPeCoffHeaderOffset = DosHdr->e_lfanew;
1746 } else {
1747 mPeCoffHeaderOffset = 0;
1748 }
1749 //
1750 // Check PE/COFF image.
1751 //
1752 mNtHeader.Pe32 = (EFI_IMAGE_NT_HEADERS32 *) (mImageBase + mPeCoffHeaderOffset);
1753 if (mNtHeader.Pe32->Signature != EFI_IMAGE_NT_SIGNATURE) {
1754 //
1755 // It is not a valid Pe/Coff file.
1756 //
1757 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Not a valid PE/COFF image.\n"));
1758 goto Failed;
1759 }
1760
1761 if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
1762 //
1763 // Use PE32 offset.
1764 //
1765 NumberOfRvaAndSizes = mNtHeader.Pe32->OptionalHeader.NumberOfRvaAndSizes;
1766 if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
1767 SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
1768 }
1769 } else {
1770 //
1771 // Use PE32+ offset.
1772 //
1773 NumberOfRvaAndSizes = mNtHeader.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes;
1774 if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
1775 SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
1776 }
1777 }
1778
1779 //
1780 // Start Image Validation.
1781 //
1782 if (SecDataDir == NULL || SecDataDir->Size == 0) {
1783 //
1784 // This image is not signed. The SHA256 hash value of the image must match a record in the security database "db",
1785 // and not be reflected in the security data base "dbx".
1786 //
1787 if (!HashPeImage (HASHALG_SHA256)) {
1788 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Failed to hash this image using %s.\n", mHashTypeStr));
1789 goto Failed;
1790 }
1791
1792 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) {
1793 //
1794 // Image Hash is in forbidden database (DBX).
1795 //
1796 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is not signed and %s hash of image is forbidden by DBX.\n", mHashTypeStr));
1797 goto Failed;
1798 }
1799
1800 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) {
1801 //
1802 // Image Hash is in allowed database (DB).
1803 //
1804 return EFI_SUCCESS;
1805 }
1806
1807 //
1808 // Image Hash is not found in both forbidden and allowed database.
1809 //
1810 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is not signed and %s hash of image is not found in DB/DBX.\n", mHashTypeStr));
1811 goto Failed;
1812 }
1813
1814 //
1815 // Verify the signature of the image, multiple signatures are allowed as per PE/COFF Section 4.7
1816 // "Attribute Certificate Table".
1817 // The first certificate starts at offset (SecDataDir->VirtualAddress) from the start of the file.
1818 //
1819 for (OffSet = SecDataDir->VirtualAddress;
1820 OffSet < (SecDataDir->VirtualAddress + SecDataDir->Size);
1821 OffSet += (WinCertificate->dwLength + ALIGN_SIZE (WinCertificate->dwLength))) {
1822 WinCertificate = (WIN_CERTIFICATE *) (mImageBase + OffSet);
1823 if ((SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) <= sizeof (WIN_CERTIFICATE) ||
1824 (SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) < WinCertificate->dwLength) {
1825 break;
1826 }
1827
1828 //
1829 // Verify the image's Authenticode signature, only DER-encoded PKCS#7 signed data is supported.
1830 //
1831 if (WinCertificate->wCertificateType == WIN_CERT_TYPE_PKCS_SIGNED_DATA) {
1832 //
1833 // The certificate is formatted as WIN_CERTIFICATE_EFI_PKCS which is described in the
1834 // Authenticode specification.
1835 //
1836 PkcsCertData = (WIN_CERTIFICATE_EFI_PKCS *) WinCertificate;
1837 if (PkcsCertData->Hdr.dwLength <= sizeof (PkcsCertData->Hdr)) {
1838 break;
1839 }
1840 AuthData = PkcsCertData->CertData;
1841 AuthDataSize = PkcsCertData->Hdr.dwLength - sizeof(PkcsCertData->Hdr);
1842 } else if (WinCertificate->wCertificateType == WIN_CERT_TYPE_EFI_GUID) {
1843 //
1844 // The certificate is formatted as WIN_CERTIFICATE_UEFI_GUID which is described in UEFI Spec.
1845 //
1846 WinCertUefiGuid = (WIN_CERTIFICATE_UEFI_GUID *) WinCertificate;
1847 if (WinCertUefiGuid->Hdr.dwLength <= OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData)) {
1848 break;
1849 }
1850 if (!CompareGuid (&WinCertUefiGuid->CertType, &gEfiCertPkcs7Guid)) {
1851 continue;
1852 }
1853 AuthData = WinCertUefiGuid->CertData;
1854 AuthDataSize = WinCertUefiGuid->Hdr.dwLength - OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData);
1855 } else {
1856 if (WinCertificate->dwLength < sizeof (WIN_CERTIFICATE)) {
1857 break;
1858 }
1859 continue;
1860 }
1861
1862 HashStatus = HashPeImageByType (AuthData, AuthDataSize);
1863 if (EFI_ERROR (HashStatus)) {
1864 continue;
1865 }
1866
1867 //
1868 // Check the digital signature against the revoked certificate in forbidden database (dbx).
1869 //
1870 if (IsForbiddenByDbx (AuthData, AuthDataSize)) {
1871 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED;
1872 IsVerified = FALSE;
1873 break;
1874 }
1875
1876 //
1877 // Check the digital signature against the valid certificate in allowed database (db).
1878 //
1879 if (!IsVerified) {
1880 if (IsAllowedByDb (AuthData, AuthDataSize)) {
1881 IsVerified = TRUE;
1882 }
1883 }
1884
1885 //
1886 // Check the image's hash value.
1887 //
1888 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) {
1889 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND;
1890 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but %s hash of image is found in DBX.\n", mHashTypeStr));
1891 IsVerified = FALSE;
1892 break;
1893 }
1894 if (!IsVerified) {
1895 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) {
1896 IsVerified = TRUE;
1897 } else {
1898 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature is not allowed by DB and %s hash of image is not found in DB/DBX.\n", mHashTypeStr));
1899 }
1900 }
1901 }
1902
1903 if (OffSet != (SecDataDir->VirtualAddress + SecDataDir->Size)) {
1904 //
1905 // The Size in Certificate Table or the attribute certificate table is corrupted.
1906 //
1907 IsVerified = FALSE;
1908 }
1909
1910 if (IsVerified) {
1911 return EFI_SUCCESS;
1912 }
1913 if (Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED || Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND) {
1914 //
1915 // Get image hash value as signature of executable.
1916 //
1917 SignatureListSize = sizeof (EFI_SIGNATURE_LIST) + sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize;
1918 SignatureList = (EFI_SIGNATURE_LIST *) AllocateZeroPool (SignatureListSize);
1919 if (SignatureList == NULL) {
1920 SignatureListSize = 0;
1921 goto Failed;
1922 }
1923 SignatureList->SignatureHeaderSize = 0;
1924 SignatureList->SignatureListSize = (UINT32) SignatureListSize;
1925 SignatureList->SignatureSize = (UINT32) (sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize);
1926 CopyMem (&SignatureList->SignatureType, &mCertType, sizeof (EFI_GUID));
1927 Signature = (EFI_SIGNATURE_DATA *) ((UINT8 *) SignatureList + sizeof (EFI_SIGNATURE_LIST));
1928 CopyMem (Signature->SignatureData, mImageDigest, mImageDigestSize);
1929 }
1930
1931 Failed:
1932 //
1933 // Policy decides to defer or reject the image; add its information in image
1934 // executable information table in either case.
1935 //
1936 NameStr = ConvertDevicePathToText (File, FALSE, TRUE);
1937 AddImageExeInfo (Action, NameStr, File, SignatureList, SignatureListSize);
1938 if (NameStr != NULL) {
1939 DEBUG ((DEBUG_INFO, "The image doesn't pass verification: %s\n", NameStr));
1940 FreePool(NameStr);
1941 }
1942
1943 if (SignatureList != NULL) {
1944 FreePool (SignatureList);
1945 }
1946
1947 if (Policy == DEFER_EXECUTE_ON_SECURITY_VIOLATION) {
1948 return EFI_SECURITY_VIOLATION;
1949 }
1950 return EFI_ACCESS_DENIED;
1951 }
1952
1953 /**
1954 On Ready To Boot Services Event notification handler.
1955
1956 Add the image execution information table if it is not in system configuration table.
1957
1958 @param[in] Event Event whose notification function is being invoked
1959 @param[in] Context Pointer to the notification function's context
1960
1961 **/
1962 VOID
1963 EFIAPI
1964 OnReadyToBoot (
1965 IN EFI_EVENT Event,
1966 IN VOID *Context
1967 )
1968 {
1969 EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable;
1970 UINTN ImageExeInfoTableSize;
1971
1972 EfiGetSystemConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID **) &ImageExeInfoTable);
1973 if (ImageExeInfoTable != NULL) {
1974 return;
1975 }
1976
1977 ImageExeInfoTableSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE);
1978 ImageExeInfoTable = (EFI_IMAGE_EXECUTION_INFO_TABLE *) AllocateRuntimePool (ImageExeInfoTableSize);
1979 if (ImageExeInfoTable == NULL) {
1980 return ;
1981 }
1982
1983 ImageExeInfoTable->NumberOfImages = 0;
1984 gBS->InstallConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID *) ImageExeInfoTable);
1985
1986 }
1987
1988 /**
1989 Register security measurement handler.
1990
1991 @param ImageHandle ImageHandle of the loaded driver.
1992 @param SystemTable Pointer to the EFI System Table.
1993
1994 @retval EFI_SUCCESS The handlers were registered successfully.
1995 **/
1996 EFI_STATUS
1997 EFIAPI
1998 DxeImageVerificationLibConstructor (
1999 IN EFI_HANDLE ImageHandle,
2000 IN EFI_SYSTEM_TABLE *SystemTable
2001 )
2002 {
2003 EFI_EVENT Event;
2004
2005 //
2006 // Register the event to publish the image execution table.
2007 //
2008 EfiCreateEventReadyToBootEx (
2009 TPL_CALLBACK,
2010 OnReadyToBoot,
2011 NULL,
2012 &Event
2013 );
2014
2015 return RegisterSecurity2Handler (
2016 DxeImageVerificationHandler,
2017 EFI_AUTH_OPERATION_VERIFY_IMAGE | EFI_AUTH_OPERATION_IMAGE_REQUIRED
2018 );
2019 }
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