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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
826 @return TRUE The certificate hash is found in the forbidden database.
827 @return FALSE The certificate hash is not found in the forbidden database.
828
829 **/
830 BOOLEAN
831 IsCertHashFoundInDatabase (
832 IN UINT8 *Certificate,
833 IN UINTN CertSize,
834 IN EFI_SIGNATURE_LIST *SignatureList,
835 IN UINTN SignatureListSize,
836 OUT EFI_TIME *RevocationTime
837 )
838 {
839 BOOLEAN IsFound;
840 BOOLEAN Status;
841 EFI_SIGNATURE_LIST *DbxList;
842 UINTN DbxSize;
843 EFI_SIGNATURE_DATA *CertHash;
844 UINTN CertHashCount;
845 UINTN Index;
846 UINT32 HashAlg;
847 VOID *HashCtx;
848 UINT8 CertDigest[MAX_DIGEST_SIZE];
849 UINT8 *DbxCertHash;
850 UINTN SiglistHeaderSize;
851 UINT8 *TBSCert;
852 UINTN TBSCertSize;
853
854 IsFound = FALSE;
855 DbxList = SignatureList;
856 DbxSize = SignatureListSize;
857 HashCtx = NULL;
858 HashAlg = HASHALG_MAX;
859
860 if ((RevocationTime == NULL) || (DbxList == NULL)) {
861 return FALSE;
862 }
863
864 //
865 // Retrieve the TBSCertificate from the X.509 Certificate.
866 //
867 if (!X509GetTBSCert (Certificate, CertSize, &TBSCert, &TBSCertSize)) {
868 return FALSE;
869 }
870
871 while ((DbxSize > 0) && (SignatureListSize >= DbxList->SignatureListSize)) {
872 //
873 // Determine Hash Algorithm of Certificate in the forbidden database.
874 //
875 if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha256Guid)) {
876 HashAlg = HASHALG_SHA256;
877 } else if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha384Guid)) {
878 HashAlg = HASHALG_SHA384;
879 } else if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha512Guid)) {
880 HashAlg = HASHALG_SHA512;
881 } else {
882 DbxSize -= DbxList->SignatureListSize;
883 DbxList = (EFI_SIGNATURE_LIST *) ((UINT8 *) DbxList + DbxList->SignatureListSize);
884 continue;
885 }
886
887 //
888 // Calculate the hash value of current TBSCertificate for comparision.
889 //
890 if (mHash[HashAlg].GetContextSize == NULL) {
891 goto Done;
892 }
893 ZeroMem (CertDigest, MAX_DIGEST_SIZE);
894 HashCtx = AllocatePool (mHash[HashAlg].GetContextSize ());
895 if (HashCtx == NULL) {
896 goto Done;
897 }
898 Status = mHash[HashAlg].HashInit (HashCtx);
899 if (!Status) {
900 goto Done;
901 }
902 Status = mHash[HashAlg].HashUpdate (HashCtx, TBSCert, TBSCertSize);
903 if (!Status) {
904 goto Done;
905 }
906 Status = mHash[HashAlg].HashFinal (HashCtx, CertDigest);
907 if (!Status) {
908 goto Done;
909 }
910
911 FreePool (HashCtx);
912 HashCtx = NULL;
913
914 SiglistHeaderSize = sizeof (EFI_SIGNATURE_LIST) + DbxList->SignatureHeaderSize;
915 CertHash = (EFI_SIGNATURE_DATA *) ((UINT8 *) DbxList + SiglistHeaderSize);
916 CertHashCount = (DbxList->SignatureListSize - SiglistHeaderSize) / DbxList->SignatureSize;
917 for (Index = 0; Index < CertHashCount; Index++) {
918 //
919 // Iterate each Signature Data Node within this CertList for verify.
920 //
921 DbxCertHash = CertHash->SignatureData;
922 if (CompareMem (DbxCertHash, CertDigest, mHash[HashAlg].DigestLength) == 0) {
923 //
924 // Hash of Certificate is found in forbidden database.
925 //
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 Done:
942 if (HashCtx != NULL) {
943 FreePool (HashCtx);
944 }
945
946 return IsFound;
947 }
948
949 /**
950 Check whether signature is in specified database.
951
952 @param[in] VariableName Name of database variable that is searched in.
953 @param[in] Signature Pointer to signature that is searched for.
954 @param[in] CertType Pointer to hash algorithm.
955 @param[in] SignatureSize Size of Signature.
956
957 @return TRUE Found the signature in the variable database.
958 @return FALSE Not found the signature in the variable database.
959
960 **/
961 BOOLEAN
962 IsSignatureFoundInDatabase (
963 IN CHAR16 *VariableName,
964 IN UINT8 *Signature,
965 IN EFI_GUID *CertType,
966 IN UINTN SignatureSize
967 )
968 {
969 EFI_STATUS Status;
970 EFI_SIGNATURE_LIST *CertList;
971 EFI_SIGNATURE_DATA *Cert;
972 UINTN DataSize;
973 UINT8 *Data;
974 UINTN Index;
975 UINTN CertCount;
976 BOOLEAN IsFound;
977
978 //
979 // Read signature database variable.
980 //
981 IsFound = FALSE;
982 Data = NULL;
983 DataSize = 0;
984 Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
985 if (Status != EFI_BUFFER_TOO_SMALL) {
986 return FALSE;
987 }
988
989 Data = (UINT8 *) AllocateZeroPool (DataSize);
990 if (Data == NULL) {
991 return FALSE;
992 }
993
994 Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, Data);
995 if (EFI_ERROR (Status)) {
996 goto Done;
997 }
998 //
999 // Enumerate all signature data in SigDB to check if signature exists for executable.
1000 //
1001 CertList = (EFI_SIGNATURE_LIST *) Data;
1002 while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
1003 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1004 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1005 if ((CertList->SignatureSize == sizeof(EFI_SIGNATURE_DATA) - 1 + SignatureSize) && (CompareGuid(&CertList->SignatureType, CertType))) {
1006 for (Index = 0; Index < CertCount; Index++) {
1007 if (CompareMem (Cert->SignatureData, Signature, SignatureSize) == 0) {
1008 //
1009 // Find the signature in database.
1010 //
1011 IsFound = TRUE;
1012 //
1013 // Entries in UEFI_IMAGE_SECURITY_DATABASE that are used to validate image should be measured
1014 //
1015 if (StrCmp(VariableName, EFI_IMAGE_SECURITY_DATABASE) == 0) {
1016 SecureBootHook (VariableName, &gEfiImageSecurityDatabaseGuid, CertList->SignatureSize, Cert);
1017 }
1018 break;
1019 }
1020
1021 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
1022 }
1023
1024 if (IsFound) {
1025 break;
1026 }
1027 }
1028
1029 DataSize -= CertList->SignatureListSize;
1030 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1031 }
1032
1033 Done:
1034 if (Data != NULL) {
1035 FreePool (Data);
1036 }
1037
1038 return IsFound;
1039 }
1040
1041 /**
1042 Check whether the timestamp is valid by comparing the signing time and the revocation time.
1043
1044 @param SigningTime A pointer to the signing time.
1045 @param RevocationTime A pointer to the revocation time.
1046
1047 @retval TRUE The SigningTime is not later than the RevocationTime.
1048 @retval FALSE The SigningTime is later than the RevocationTime.
1049
1050 **/
1051 BOOLEAN
1052 IsValidSignatureByTimestamp (
1053 IN EFI_TIME *SigningTime,
1054 IN EFI_TIME *RevocationTime
1055 )
1056 {
1057 if (SigningTime->Year != RevocationTime->Year) {
1058 return (BOOLEAN) (SigningTime->Year < RevocationTime->Year);
1059 } else if (SigningTime->Month != RevocationTime->Month) {
1060 return (BOOLEAN) (SigningTime->Month < RevocationTime->Month);
1061 } else if (SigningTime->Day != RevocationTime->Day) {
1062 return (BOOLEAN) (SigningTime->Day < RevocationTime->Day);
1063 } else if (SigningTime->Hour != RevocationTime->Hour) {
1064 return (BOOLEAN) (SigningTime->Hour < RevocationTime->Hour);
1065 } else if (SigningTime->Minute != RevocationTime->Minute) {
1066 return (BOOLEAN) (SigningTime->Minute < RevocationTime->Minute);
1067 }
1068
1069 return (BOOLEAN) (SigningTime->Second <= RevocationTime->Second);
1070 }
1071
1072 /**
1073 Check if the given time value is zero.
1074
1075 @param[in] Time Pointer of a time value.
1076
1077 @retval TRUE The Time is Zero.
1078 @retval FALSE The Time is not Zero.
1079
1080 **/
1081 BOOLEAN
1082 IsTimeZero (
1083 IN EFI_TIME *Time
1084 )
1085 {
1086 if ((Time->Year == 0) && (Time->Month == 0) && (Time->Day == 0) &&
1087 (Time->Hour == 0) && (Time->Minute == 0) && (Time->Second == 0)) {
1088 return TRUE;
1089 }
1090
1091 return FALSE;
1092 }
1093
1094 /**
1095 Check whether the timestamp signature is valid and the signing time is also earlier than
1096 the revocation time.
1097
1098 @param[in] AuthData Pointer to the Authenticode signature retrieved from signed image.
1099 @param[in] AuthDataSize Size of the Authenticode signature in bytes.
1100 @param[in] RevocationTime The time that the certificate was revoked.
1101
1102 @retval TRUE Timestamp signature is valid and signing time is no later than the
1103 revocation time.
1104 @retval FALSE Timestamp signature is not valid or the signing time is later than the
1105 revocation time.
1106
1107 **/
1108 BOOLEAN
1109 PassTimestampCheck (
1110 IN UINT8 *AuthData,
1111 IN UINTN AuthDataSize,
1112 IN EFI_TIME *RevocationTime
1113 )
1114 {
1115 EFI_STATUS Status;
1116 BOOLEAN VerifyStatus;
1117 EFI_SIGNATURE_LIST *CertList;
1118 EFI_SIGNATURE_DATA *Cert;
1119 UINT8 *DbtData;
1120 UINTN DbtDataSize;
1121 UINT8 *RootCert;
1122 UINTN RootCertSize;
1123 UINTN Index;
1124 UINTN CertCount;
1125 EFI_TIME SigningTime;
1126
1127 //
1128 // Variable Initialization
1129 //
1130 VerifyStatus = FALSE;
1131 DbtData = NULL;
1132 CertList = NULL;
1133 Cert = NULL;
1134 RootCert = NULL;
1135 RootCertSize = 0;
1136
1137 //
1138 // If RevocationTime is zero, the certificate shall be considered to always be revoked.
1139 //
1140 if (IsTimeZero (RevocationTime)) {
1141 return FALSE;
1142 }
1143
1144 //
1145 // RevocationTime is non-zero, the certificate should be considered to be revoked from that time and onwards.
1146 // Using the dbt to get the trusted TSA certificates.
1147 //
1148 DbtDataSize = 0;
1149 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE2, &gEfiImageSecurityDatabaseGuid, NULL, &DbtDataSize, NULL);
1150 if (Status != EFI_BUFFER_TOO_SMALL) {
1151 goto Done;
1152 }
1153 DbtData = (UINT8 *) AllocateZeroPool (DbtDataSize);
1154 if (DbtData == NULL) {
1155 goto Done;
1156 }
1157 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE2, &gEfiImageSecurityDatabaseGuid, NULL, &DbtDataSize, (VOID *) DbtData);
1158 if (EFI_ERROR (Status)) {
1159 goto Done;
1160 }
1161
1162 CertList = (EFI_SIGNATURE_LIST *) DbtData;
1163 while ((DbtDataSize > 0) && (DbtDataSize >= CertList->SignatureListSize)) {
1164 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
1165 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1166 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1167 for (Index = 0; Index < CertCount; Index++) {
1168 //
1169 // Iterate each Signature Data Node within this CertList for verify.
1170 //
1171 RootCert = Cert->SignatureData;
1172 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
1173 //
1174 // Get the signing time if the timestamp signature is valid.
1175 //
1176 if (ImageTimestampVerify (AuthData, AuthDataSize, RootCert, RootCertSize, &SigningTime)) {
1177 //
1178 // The signer signature is valid only when the signing time is earlier than revocation time.
1179 //
1180 if (IsValidSignatureByTimestamp (&SigningTime, RevocationTime)) {
1181 VerifyStatus = TRUE;
1182 goto Done;
1183 }
1184 }
1185 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
1186 }
1187 }
1188 DbtDataSize -= CertList->SignatureListSize;
1189 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1190 }
1191
1192 Done:
1193 if (DbtData != NULL) {
1194 FreePool (DbtData);
1195 }
1196
1197 return VerifyStatus;
1198 }
1199
1200 /**
1201 Check whether the image signature is forbidden by the forbidden database (dbx).
1202 The image is forbidden to load if any certificates for signing are revoked before signing time.
1203
1204 @param[in] AuthData Pointer to the Authenticode signature retrieved from the signed image.
1205 @param[in] AuthDataSize Size of the Authenticode signature in bytes.
1206
1207 @retval TRUE Image is forbidden by dbx.
1208 @retval FALSE Image is not forbidden by dbx.
1209
1210 **/
1211 BOOLEAN
1212 IsForbiddenByDbx (
1213 IN UINT8 *AuthData,
1214 IN UINTN AuthDataSize
1215 )
1216 {
1217 EFI_STATUS Status;
1218 BOOLEAN IsForbidden;
1219 UINT8 *Data;
1220 UINTN DataSize;
1221 EFI_SIGNATURE_LIST *CertList;
1222 UINTN CertListSize;
1223 EFI_SIGNATURE_DATA *CertData;
1224 UINT8 *RootCert;
1225 UINTN RootCertSize;
1226 UINTN CertCount;
1227 UINTN Index;
1228 UINT8 *CertBuffer;
1229 UINTN BufferLength;
1230 UINT8 *TrustedCert;
1231 UINTN TrustedCertLength;
1232 UINT8 CertNumber;
1233 UINT8 *CertPtr;
1234 UINT8 *Cert;
1235 UINTN CertSize;
1236 EFI_TIME RevocationTime;
1237 //
1238 // Variable Initialization
1239 //
1240 IsForbidden = FALSE;
1241 Data = NULL;
1242 CertList = NULL;
1243 CertData = NULL;
1244 RootCert = NULL;
1245 RootCertSize = 0;
1246 Cert = NULL;
1247 CertBuffer = NULL;
1248 BufferLength = 0;
1249 TrustedCert = NULL;
1250 TrustedCertLength = 0;
1251
1252 //
1253 // The image will not be forbidden if dbx can't be got.
1254 //
1255 DataSize = 0;
1256 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
1257 if (Status != EFI_BUFFER_TOO_SMALL) {
1258 return IsForbidden;
1259 }
1260 Data = (UINT8 *) AllocateZeroPool (DataSize);
1261 if (Data == NULL) {
1262 return IsForbidden;
1263 }
1264
1265 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data);
1266 if (EFI_ERROR (Status)) {
1267 return IsForbidden;
1268 }
1269
1270 //
1271 // Verify image signature with RAW X509 certificates in DBX database.
1272 // If passed, the image will be forbidden.
1273 //
1274 CertList = (EFI_SIGNATURE_LIST *) Data;
1275 CertListSize = DataSize;
1276 while ((CertListSize > 0) && (CertListSize >= CertList->SignatureListSize)) {
1277 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
1278 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1279 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1280
1281 for (Index = 0; Index < CertCount; Index++) {
1282 //
1283 // Iterate each Signature Data Node within this CertList for verify.
1284 //
1285 RootCert = CertData->SignatureData;
1286 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
1287
1288 //
1289 // Call AuthenticodeVerify library to Verify Authenticode struct.
1290 //
1291 IsForbidden = AuthenticodeVerify (
1292 AuthData,
1293 AuthDataSize,
1294 RootCert,
1295 RootCertSize,
1296 mImageDigest,
1297 mImageDigestSize
1298 );
1299 if (IsForbidden) {
1300 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature is forbidden by DBX.\n"));
1301 goto Done;
1302 }
1303
1304 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize);
1305 }
1306 }
1307
1308 CertListSize -= CertList->SignatureListSize;
1309 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1310 }
1311
1312 //
1313 // Check X.509 Certificate Hash & Possible Timestamp.
1314 //
1315
1316 //
1317 // Retrieve the certificate stack from AuthData
1318 // The output CertStack format will be:
1319 // UINT8 CertNumber;
1320 // UINT32 Cert1Length;
1321 // UINT8 Cert1[];
1322 // UINT32 Cert2Length;
1323 // UINT8 Cert2[];
1324 // ...
1325 // UINT32 CertnLength;
1326 // UINT8 Certn[];
1327 //
1328 Pkcs7GetSigners (AuthData, AuthDataSize, &CertBuffer, &BufferLength, &TrustedCert, &TrustedCertLength);
1329 if ((BufferLength == 0) || (CertBuffer == NULL) || (*CertBuffer) == 0) {
1330 IsForbidden = TRUE;
1331 goto Done;
1332 }
1333
1334 //
1335 // Check if any hash of certificates embedded in AuthData is in the forbidden database.
1336 //
1337 CertNumber = (UINT8) (*CertBuffer);
1338 CertPtr = CertBuffer + 1;
1339 for (Index = 0; Index < CertNumber; Index++) {
1340 CertSize = (UINTN) ReadUnaligned32 ((UINT32 *)CertPtr);
1341 Cert = (UINT8 *)CertPtr + sizeof (UINT32);
1342 //
1343 // Advance CertPtr to the next cert in image signer's cert list
1344 //
1345 CertPtr = CertPtr + sizeof (UINT32) + CertSize;
1346
1347 if (IsCertHashFoundInDatabase (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data, DataSize, &RevocationTime)) {
1348 //
1349 // Check the timestamp signature and signing time to determine if the image can be trusted.
1350 //
1351 IsForbidden = TRUE;
1352 if (PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime)) {
1353 IsForbidden = FALSE;
1354 //
1355 // Pass DBT check. Continue to check other certs in image signer's cert list against DBX, DBT
1356 //
1357 continue;
1358 }
1359 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature failed the timestamp check.\n"));
1360 goto Done;
1361 }
1362
1363 }
1364
1365 Done:
1366 if (Data != NULL) {
1367 FreePool (Data);
1368 }
1369
1370 Pkcs7FreeSigners (CertBuffer);
1371 Pkcs7FreeSigners (TrustedCert);
1372
1373 return IsForbidden;
1374 }
1375
1376
1377 /**
1378 Check whether the image signature can be verified by the trusted certificates in DB database.
1379
1380 @param[in] AuthData Pointer to the Authenticode signature retrieved from signed image.
1381 @param[in] AuthDataSize Size of the Authenticode signature in bytes.
1382
1383 @retval TRUE Image passed verification using certificate in db.
1384 @retval FALSE Image didn't pass verification using certificate in db.
1385
1386 **/
1387 BOOLEAN
1388 IsAllowedByDb (
1389 IN UINT8 *AuthData,
1390 IN UINTN AuthDataSize
1391 )
1392 {
1393 EFI_STATUS Status;
1394 BOOLEAN VerifyStatus;
1395 EFI_SIGNATURE_LIST *CertList;
1396 EFI_SIGNATURE_DATA *CertData;
1397 UINTN DataSize;
1398 UINT8 *Data;
1399 UINT8 *RootCert;
1400 UINTN RootCertSize;
1401 UINTN Index;
1402 UINTN CertCount;
1403 UINTN DbxDataSize;
1404 UINT8 *DbxData;
1405 EFI_TIME RevocationTime;
1406
1407 Data = NULL;
1408 CertList = NULL;
1409 CertData = NULL;
1410 RootCert = NULL;
1411 DbxData = NULL;
1412 RootCertSize = 0;
1413 VerifyStatus = FALSE;
1414
1415 DataSize = 0;
1416 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
1417 if (Status == EFI_BUFFER_TOO_SMALL) {
1418 Data = (UINT8 *) AllocateZeroPool (DataSize);
1419 if (Data == NULL) {
1420 return VerifyStatus;
1421 }
1422
1423 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data);
1424 if (EFI_ERROR (Status)) {
1425 goto Done;
1426 }
1427
1428 //
1429 // Find X509 certificate in Signature List to verify the signature in pkcs7 signed data.
1430 //
1431 CertList = (EFI_SIGNATURE_LIST *) Data;
1432 while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
1433 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
1434 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1435 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1436
1437 for (Index = 0; Index < CertCount; Index++) {
1438 //
1439 // Iterate each Signature Data Node within this CertList for verify.
1440 //
1441 RootCert = CertData->SignatureData;
1442 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
1443
1444 //
1445 // Call AuthenticodeVerify library to Verify Authenticode struct.
1446 //
1447 VerifyStatus = AuthenticodeVerify (
1448 AuthData,
1449 AuthDataSize,
1450 RootCert,
1451 RootCertSize,
1452 mImageDigest,
1453 mImageDigestSize
1454 );
1455 if (VerifyStatus) {
1456 //
1457 // Here We still need to check if this RootCert's Hash is revoked
1458 //
1459 DbxDataSize = 0;
1460 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, NULL);
1461 if (Status != EFI_BUFFER_TOO_SMALL) {
1462 goto Done;
1463 }
1464 DbxData = (UINT8 *) AllocateZeroPool (DbxDataSize);
1465 if (DbxData == NULL) {
1466 goto Done;
1467 }
1468
1469 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, (VOID *) DbxData);
1470 if (EFI_ERROR (Status)) {
1471 goto Done;
1472 }
1473
1474 if (IsCertHashFoundInDatabase (RootCert, RootCertSize, (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime)) {
1475 //
1476 // Check the timestamp signature and signing time to determine if the RootCert can be trusted.
1477 //
1478 VerifyStatus = PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime);
1479 if (!VerifyStatus) {
1480 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed and signature is accepted by DB, but its root cert failed the timestamp check.\n"));
1481 }
1482 }
1483
1484 goto Done;
1485 }
1486
1487 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize);
1488 }
1489 }
1490
1491 DataSize -= CertList->SignatureListSize;
1492 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1493 }
1494 }
1495
1496 Done:
1497
1498 if (VerifyStatus) {
1499 SecureBootHook (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, CertList->SignatureSize, CertData);
1500 }
1501
1502 if (Data != NULL) {
1503 FreePool (Data);
1504 }
1505 if (DbxData != NULL) {
1506 FreePool (DbxData);
1507 }
1508
1509 return VerifyStatus;
1510 }
1511
1512 /**
1513 Provide verification service for signed images, which include both signature validation
1514 and platform policy control. For signature types, both UEFI WIN_CERTIFICATE_UEFI_GUID and
1515 MSFT Authenticode type signatures are supported.
1516
1517 In this implementation, only verify external executables when in USER MODE.
1518 Executables from FV is bypass, so pass in AuthenticationStatus is ignored.
1519
1520 The image verification policy is:
1521 If the image is signed,
1522 At least one valid signature or at least one hash value of the image must match a record
1523 in the security database "db", and no valid signature nor any hash value of the image may
1524 be reflected in the security database "dbx".
1525 Otherwise, the image is not signed,
1526 The SHA256 hash value of the image must match a record in the security database "db", and
1527 not be reflected in the security data base "dbx".
1528
1529 Caution: This function may receive untrusted input.
1530 PE/COFF image is external input, so this function will validate its data structure
1531 within this image buffer before use.
1532
1533 @param[in] AuthenticationStatus
1534 This is the authentication status returned from the security
1535 measurement services for the input file.
1536 @param[in] File This is a pointer to the device path of the file that is
1537 being dispatched. This will optionally be used for logging.
1538 @param[in] FileBuffer File buffer matches the input file device path.
1539 @param[in] FileSize Size of File buffer matches the input file device path.
1540 @param[in] BootPolicy A boot policy that was used to call LoadImage() UEFI service.
1541
1542 @retval EFI_SUCCESS The file specified by DevicePath and non-NULL
1543 FileBuffer did authenticate, and the platform policy dictates
1544 that the DXE Foundation may use the file.
1545 @retval EFI_SUCCESS The device path specified by NULL device path DevicePath
1546 and non-NULL FileBuffer did authenticate, and the platform
1547 policy dictates that the DXE Foundation may execute the image in
1548 FileBuffer.
1549 @retval EFI_SECURITY_VIOLATION The file specified by File did not authenticate, and
1550 the platform policy dictates that File should be placed
1551 in the untrusted state. The image has been added to the file
1552 execution table.
1553 @retval EFI_ACCESS_DENIED The file specified by File and FileBuffer did not
1554 authenticate, and the platform policy dictates that the DXE
1555 Foundation may not use File. The image has
1556 been added to the file execution table.
1557
1558 **/
1559 EFI_STATUS
1560 EFIAPI
1561 DxeImageVerificationHandler (
1562 IN UINT32 AuthenticationStatus,
1563 IN CONST EFI_DEVICE_PATH_PROTOCOL *File,
1564 IN VOID *FileBuffer,
1565 IN UINTN FileSize,
1566 IN BOOLEAN BootPolicy
1567 )
1568 {
1569 EFI_IMAGE_DOS_HEADER *DosHdr;
1570 BOOLEAN IsVerified;
1571 EFI_SIGNATURE_LIST *SignatureList;
1572 UINTN SignatureListSize;
1573 EFI_SIGNATURE_DATA *Signature;
1574 EFI_IMAGE_EXECUTION_ACTION Action;
1575 WIN_CERTIFICATE *WinCertificate;
1576 UINT32 Policy;
1577 UINT8 *SecureBoot;
1578 PE_COFF_LOADER_IMAGE_CONTEXT ImageContext;
1579 UINT32 NumberOfRvaAndSizes;
1580 WIN_CERTIFICATE_EFI_PKCS *PkcsCertData;
1581 WIN_CERTIFICATE_UEFI_GUID *WinCertUefiGuid;
1582 UINT8 *AuthData;
1583 UINTN AuthDataSize;
1584 EFI_IMAGE_DATA_DIRECTORY *SecDataDir;
1585 UINT32 OffSet;
1586 CHAR16 *NameStr;
1587 RETURN_STATUS PeCoffStatus;
1588 EFI_STATUS HashStatus;
1589
1590 SignatureList = NULL;
1591 SignatureListSize = 0;
1592 WinCertificate = NULL;
1593 SecDataDir = NULL;
1594 PkcsCertData = NULL;
1595 Action = EFI_IMAGE_EXECUTION_AUTH_UNTESTED;
1596 IsVerified = FALSE;
1597
1598
1599 //
1600 // Check the image type and get policy setting.
1601 //
1602 switch (GetImageType (File)) {
1603
1604 case IMAGE_FROM_FV:
1605 Policy = ALWAYS_EXECUTE;
1606 break;
1607
1608 case IMAGE_FROM_OPTION_ROM:
1609 Policy = PcdGet32 (PcdOptionRomImageVerificationPolicy);
1610 break;
1611
1612 case IMAGE_FROM_REMOVABLE_MEDIA:
1613 Policy = PcdGet32 (PcdRemovableMediaImageVerificationPolicy);
1614 break;
1615
1616 case IMAGE_FROM_FIXED_MEDIA:
1617 Policy = PcdGet32 (PcdFixedMediaImageVerificationPolicy);
1618 break;
1619
1620 default:
1621 Policy = DENY_EXECUTE_ON_SECURITY_VIOLATION;
1622 break;
1623 }
1624 //
1625 // If policy is always/never execute, return directly.
1626 //
1627 if (Policy == ALWAYS_EXECUTE) {
1628 return EFI_SUCCESS;
1629 }
1630 if (Policy == NEVER_EXECUTE) {
1631 return EFI_ACCESS_DENIED;
1632 }
1633
1634 //
1635 // The policy QUERY_USER_ON_SECURITY_VIOLATION and ALLOW_EXECUTE_ON_SECURITY_VIOLATION
1636 // violates the UEFI spec and has been removed.
1637 //
1638 ASSERT (Policy != QUERY_USER_ON_SECURITY_VIOLATION && Policy != ALLOW_EXECUTE_ON_SECURITY_VIOLATION);
1639 if (Policy == QUERY_USER_ON_SECURITY_VIOLATION || Policy == ALLOW_EXECUTE_ON_SECURITY_VIOLATION) {
1640 CpuDeadLoop ();
1641 }
1642
1643 GetEfiGlobalVariable2 (EFI_SECURE_BOOT_MODE_NAME, (VOID**)&SecureBoot, NULL);
1644 //
1645 // Skip verification if SecureBoot variable doesn't exist.
1646 //
1647 if (SecureBoot == NULL) {
1648 return EFI_SUCCESS;
1649 }
1650
1651 //
1652 // Skip verification if SecureBoot is disabled but not AuditMode
1653 //
1654 if (*SecureBoot == SECURE_BOOT_MODE_DISABLE) {
1655 FreePool (SecureBoot);
1656 return EFI_SUCCESS;
1657 }
1658 FreePool (SecureBoot);
1659
1660 //
1661 // Read the Dos header.
1662 //
1663 if (FileBuffer == NULL) {
1664 return EFI_ACCESS_DENIED;
1665 }
1666
1667 mImageBase = (UINT8 *) FileBuffer;
1668 mImageSize = FileSize;
1669
1670 ZeroMem (&ImageContext, sizeof (ImageContext));
1671 ImageContext.Handle = (VOID *) FileBuffer;
1672 ImageContext.ImageRead = (PE_COFF_LOADER_READ_FILE) DxeImageVerificationLibImageRead;
1673
1674 //
1675 // Get information about the image being loaded
1676 //
1677 PeCoffStatus = PeCoffLoaderGetImageInfo (&ImageContext);
1678 if (RETURN_ERROR (PeCoffStatus)) {
1679 //
1680 // The information can't be got from the invalid PeImage
1681 //
1682 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: PeImage invalid. Cannot retrieve image information.\n"));
1683 goto Failed;
1684 }
1685
1686 DosHdr = (EFI_IMAGE_DOS_HEADER *) mImageBase;
1687 if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) {
1688 //
1689 // DOS image header is present,
1690 // so read the PE header after the DOS image header.
1691 //
1692 mPeCoffHeaderOffset = DosHdr->e_lfanew;
1693 } else {
1694 mPeCoffHeaderOffset = 0;
1695 }
1696 //
1697 // Check PE/COFF image.
1698 //
1699 mNtHeader.Pe32 = (EFI_IMAGE_NT_HEADERS32 *) (mImageBase + mPeCoffHeaderOffset);
1700 if (mNtHeader.Pe32->Signature != EFI_IMAGE_NT_SIGNATURE) {
1701 //
1702 // It is not a valid Pe/Coff file.
1703 //
1704 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Not a valid PE/COFF image.\n"));
1705 goto Failed;
1706 }
1707
1708 if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
1709 //
1710 // Use PE32 offset.
1711 //
1712 NumberOfRvaAndSizes = mNtHeader.Pe32->OptionalHeader.NumberOfRvaAndSizes;
1713 if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
1714 SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
1715 }
1716 } else {
1717 //
1718 // Use PE32+ offset.
1719 //
1720 NumberOfRvaAndSizes = mNtHeader.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes;
1721 if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
1722 SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
1723 }
1724 }
1725
1726 //
1727 // Start Image Validation.
1728 //
1729 if (SecDataDir == NULL || SecDataDir->Size == 0) {
1730 //
1731 // This image is not signed. The SHA256 hash value of the image must match a record in the security database "db",
1732 // and not be reflected in the security data base "dbx".
1733 //
1734 if (!HashPeImage (HASHALG_SHA256)) {
1735 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Failed to hash this image using %s.\n", mHashTypeStr));
1736 goto Failed;
1737 }
1738
1739 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) {
1740 //
1741 // Image Hash is in forbidden database (DBX).
1742 //
1743 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is not signed and %s hash of image is forbidden by DBX.\n", mHashTypeStr));
1744 goto Failed;
1745 }
1746
1747 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) {
1748 //
1749 // Image Hash is in allowed database (DB).
1750 //
1751 return EFI_SUCCESS;
1752 }
1753
1754 //
1755 // Image Hash is not found in both forbidden and allowed database.
1756 //
1757 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is not signed and %s hash of image is not found in DB/DBX.\n", mHashTypeStr));
1758 goto Failed;
1759 }
1760
1761 //
1762 // Verify the signature of the image, multiple signatures are allowed as per PE/COFF Section 4.7
1763 // "Attribute Certificate Table".
1764 // The first certificate starts at offset (SecDataDir->VirtualAddress) from the start of the file.
1765 //
1766 for (OffSet = SecDataDir->VirtualAddress;
1767 OffSet < (SecDataDir->VirtualAddress + SecDataDir->Size);
1768 OffSet += (WinCertificate->dwLength + ALIGN_SIZE (WinCertificate->dwLength))) {
1769 WinCertificate = (WIN_CERTIFICATE *) (mImageBase + OffSet);
1770 if ((SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) <= sizeof (WIN_CERTIFICATE) ||
1771 (SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) < WinCertificate->dwLength) {
1772 break;
1773 }
1774
1775 //
1776 // Verify the image's Authenticode signature, only DER-encoded PKCS#7 signed data is supported.
1777 //
1778 if (WinCertificate->wCertificateType == WIN_CERT_TYPE_PKCS_SIGNED_DATA) {
1779 //
1780 // The certificate is formatted as WIN_CERTIFICATE_EFI_PKCS which is described in the
1781 // Authenticode specification.
1782 //
1783 PkcsCertData = (WIN_CERTIFICATE_EFI_PKCS *) WinCertificate;
1784 if (PkcsCertData->Hdr.dwLength <= sizeof (PkcsCertData->Hdr)) {
1785 break;
1786 }
1787 AuthData = PkcsCertData->CertData;
1788 AuthDataSize = PkcsCertData->Hdr.dwLength - sizeof(PkcsCertData->Hdr);
1789 } else if (WinCertificate->wCertificateType == WIN_CERT_TYPE_EFI_GUID) {
1790 //
1791 // The certificate is formatted as WIN_CERTIFICATE_UEFI_GUID which is described in UEFI Spec.
1792 //
1793 WinCertUefiGuid = (WIN_CERTIFICATE_UEFI_GUID *) WinCertificate;
1794 if (WinCertUefiGuid->Hdr.dwLength <= OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData)) {
1795 break;
1796 }
1797 if (!CompareGuid (&WinCertUefiGuid->CertType, &gEfiCertPkcs7Guid)) {
1798 continue;
1799 }
1800 AuthData = WinCertUefiGuid->CertData;
1801 AuthDataSize = WinCertUefiGuid->Hdr.dwLength - OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData);
1802 } else {
1803 if (WinCertificate->dwLength < sizeof (WIN_CERTIFICATE)) {
1804 break;
1805 }
1806 continue;
1807 }
1808
1809 HashStatus = HashPeImageByType (AuthData, AuthDataSize);
1810 if (EFI_ERROR (HashStatus)) {
1811 continue;
1812 }
1813
1814 //
1815 // Check the digital signature against the revoked certificate in forbidden database (dbx).
1816 //
1817 if (IsForbiddenByDbx (AuthData, AuthDataSize)) {
1818 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED;
1819 IsVerified = FALSE;
1820 break;
1821 }
1822
1823 //
1824 // Check the digital signature against the valid certificate in allowed database (db).
1825 //
1826 if (!IsVerified) {
1827 if (IsAllowedByDb (AuthData, AuthDataSize)) {
1828 IsVerified = TRUE;
1829 }
1830 }
1831
1832 //
1833 // Check the image's hash value.
1834 //
1835 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) {
1836 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND;
1837 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but %s hash of image is found in DBX.\n", mHashTypeStr));
1838 IsVerified = FALSE;
1839 break;
1840 }
1841 if (!IsVerified) {
1842 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) {
1843 IsVerified = TRUE;
1844 } else {
1845 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));
1846 }
1847 }
1848 }
1849
1850 if (OffSet != (SecDataDir->VirtualAddress + SecDataDir->Size)) {
1851 //
1852 // The Size in Certificate Table or the attribute certificate table is corrupted.
1853 //
1854 IsVerified = FALSE;
1855 }
1856
1857 if (IsVerified) {
1858 return EFI_SUCCESS;
1859 }
1860 if (Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED || Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND) {
1861 //
1862 // Get image hash value as signature of executable.
1863 //
1864 SignatureListSize = sizeof (EFI_SIGNATURE_LIST) + sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize;
1865 SignatureList = (EFI_SIGNATURE_LIST *) AllocateZeroPool (SignatureListSize);
1866 if (SignatureList == NULL) {
1867 SignatureListSize = 0;
1868 goto Failed;
1869 }
1870 SignatureList->SignatureHeaderSize = 0;
1871 SignatureList->SignatureListSize = (UINT32) SignatureListSize;
1872 SignatureList->SignatureSize = (UINT32) (sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize);
1873 CopyMem (&SignatureList->SignatureType, &mCertType, sizeof (EFI_GUID));
1874 Signature = (EFI_SIGNATURE_DATA *) ((UINT8 *) SignatureList + sizeof (EFI_SIGNATURE_LIST));
1875 CopyMem (Signature->SignatureData, mImageDigest, mImageDigestSize);
1876 }
1877
1878 Failed:
1879 //
1880 // Policy decides to defer or reject the image; add its information in image
1881 // executable information table in either case.
1882 //
1883 NameStr = ConvertDevicePathToText (File, FALSE, TRUE);
1884 AddImageExeInfo (Action, NameStr, File, SignatureList, SignatureListSize);
1885 if (NameStr != NULL) {
1886 DEBUG ((DEBUG_INFO, "The image doesn't pass verification: %s\n", NameStr));
1887 FreePool(NameStr);
1888 }
1889
1890 if (SignatureList != NULL) {
1891 FreePool (SignatureList);
1892 }
1893
1894 if (Policy == DEFER_EXECUTE_ON_SECURITY_VIOLATION) {
1895 return EFI_SECURITY_VIOLATION;
1896 }
1897 return EFI_ACCESS_DENIED;
1898 }
1899
1900 /**
1901 On Ready To Boot Services Event notification handler.
1902
1903 Add the image execution information table if it is not in system configuration table.
1904
1905 @param[in] Event Event whose notification function is being invoked
1906 @param[in] Context Pointer to the notification function's context
1907
1908 **/
1909 VOID
1910 EFIAPI
1911 OnReadyToBoot (
1912 IN EFI_EVENT Event,
1913 IN VOID *Context
1914 )
1915 {
1916 EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable;
1917 UINTN ImageExeInfoTableSize;
1918
1919 EfiGetSystemConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID **) &ImageExeInfoTable);
1920 if (ImageExeInfoTable != NULL) {
1921 return;
1922 }
1923
1924 ImageExeInfoTableSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE);
1925 ImageExeInfoTable = (EFI_IMAGE_EXECUTION_INFO_TABLE *) AllocateRuntimePool (ImageExeInfoTableSize);
1926 if (ImageExeInfoTable == NULL) {
1927 return ;
1928 }
1929
1930 ImageExeInfoTable->NumberOfImages = 0;
1931 gBS->InstallConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID *) ImageExeInfoTable);
1932
1933 }
1934
1935 /**
1936 Register security measurement handler.
1937
1938 @param ImageHandle ImageHandle of the loaded driver.
1939 @param SystemTable Pointer to the EFI System Table.
1940
1941 @retval EFI_SUCCESS The handlers were registered successfully.
1942 **/
1943 EFI_STATUS
1944 EFIAPI
1945 DxeImageVerificationLibConstructor (
1946 IN EFI_HANDLE ImageHandle,
1947 IN EFI_SYSTEM_TABLE *SystemTable
1948 )
1949 {
1950 EFI_EVENT Event;
1951
1952 //
1953 // Register the event to publish the image execution table.
1954 //
1955 EfiCreateEventReadyToBootEx (
1956 TPL_CALLBACK,
1957 OnReadyToBoot,
1958 NULL,
1959 &Event
1960 );
1961
1962 return RegisterSecurity2Handler (
1963 DxeImageVerificationHandler,
1964 EFI_AUTH_OPERATION_VERIFY_IMAGE | EFI_AUTH_OPERATION_IMAGE_REQUIRED
1965 );
1966 }
EFI Development Kit II mirror for PVE