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SecurityPkg/DxeImageVerificationHandler: fix retval for (FileBuffer==NULL)
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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.
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 NewImageExeInfoEntrySize = sizeof (EFI_IMAGE_EXECUTION_INFO) + NameStringLen + DevicePathSize + SignatureSize;
765
766 NewImageExeInfoTable = (EFI_IMAGE_EXECUTION_INFO_TABLE *) AllocateRuntimePool (ImageExeInfoTableSize + NewImageExeInfoEntrySize);
767 if (NewImageExeInfoTable == NULL) {
768 return ;
769 }
770
771 if (ImageExeInfoTable != NULL) {
772 CopyMem (NewImageExeInfoTable, ImageExeInfoTable, ImageExeInfoTableSize);
773 } else {
774 NewImageExeInfoTable->NumberOfImages = 0;
775 }
776 NewImageExeInfoTable->NumberOfImages++;
777 ImageExeInfoEntry = (EFI_IMAGE_EXECUTION_INFO *) ((UINT8 *) NewImageExeInfoTable + ImageExeInfoTableSize);
778 //
779 // Update new item's information.
780 //
781 WriteUnaligned32 ((UINT32 *) ImageExeInfoEntry, Action);
782 WriteUnaligned32 ((UINT32 *) ((UINT8 *) ImageExeInfoEntry + sizeof (EFI_IMAGE_EXECUTION_ACTION)), (UINT32) NewImageExeInfoEntrySize);
783
784 NameStr = (CHAR16 *)(ImageExeInfoEntry + 1);
785 if (Name != NULL) {
786 CopyMem ((UINT8 *) NameStr, Name, NameStringLen);
787 } else {
788 ZeroMem ((UINT8 *) NameStr, sizeof (CHAR16));
789 }
790
791 CopyMem (
792 (UINT8 *) NameStr + NameStringLen,
793 DevicePath,
794 DevicePathSize
795 );
796 if (Signature != NULL) {
797 CopyMem (
798 (UINT8 *) NameStr + NameStringLen + DevicePathSize,
799 Signature,
800 SignatureSize
801 );
802 }
803 //
804 // Update/replace the image execution table.
805 //
806 gBS->InstallConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID *) NewImageExeInfoTable);
807
808 //
809 // Free Old table data!
810 //
811 if (ImageExeInfoTable != NULL) {
812 FreePool (ImageExeInfoTable);
813 }
814 }
815
816 /**
817 Check whether the hash of an given X.509 certificate is in forbidden database (DBX).
818
819 @param[in] Certificate Pointer to X.509 Certificate that is searched for.
820 @param[in] CertSize Size of X.509 Certificate.
821 @param[in] SignatureList Pointer to the Signature List in forbidden database.
822 @param[in] SignatureListSize Size of Signature List.
823 @param[out] RevocationTime Return the time that the certificate was revoked.
824
825 @return TRUE The certificate hash is found in the forbidden database.
826 @return FALSE The certificate hash is not found in the forbidden database.
827
828 **/
829 BOOLEAN
830 IsCertHashFoundInDatabase (
831 IN UINT8 *Certificate,
832 IN UINTN CertSize,
833 IN EFI_SIGNATURE_LIST *SignatureList,
834 IN UINTN SignatureListSize,
835 OUT EFI_TIME *RevocationTime
836 )
837 {
838 BOOLEAN IsFound;
839 BOOLEAN Status;
840 EFI_SIGNATURE_LIST *DbxList;
841 UINTN DbxSize;
842 EFI_SIGNATURE_DATA *CertHash;
843 UINTN CertHashCount;
844 UINTN Index;
845 UINT32 HashAlg;
846 VOID *HashCtx;
847 UINT8 CertDigest[MAX_DIGEST_SIZE];
848 UINT8 *DbxCertHash;
849 UINTN SiglistHeaderSize;
850 UINT8 *TBSCert;
851 UINTN TBSCertSize;
852
853 IsFound = FALSE;
854 DbxList = SignatureList;
855 DbxSize = SignatureListSize;
856 HashCtx = NULL;
857 HashAlg = HASHALG_MAX;
858
859 if ((RevocationTime == NULL) || (DbxList == NULL)) {
860 return FALSE;
861 }
862
863 //
864 // Retrieve the TBSCertificate from the X.509 Certificate.
865 //
866 if (!X509GetTBSCert (Certificate, CertSize, &TBSCert, &TBSCertSize)) {
867 return FALSE;
868 }
869
870 while ((DbxSize > 0) && (SignatureListSize >= DbxList->SignatureListSize)) {
871 //
872 // Determine Hash Algorithm of Certificate in the forbidden database.
873 //
874 if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha256Guid)) {
875 HashAlg = HASHALG_SHA256;
876 } else if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha384Guid)) {
877 HashAlg = HASHALG_SHA384;
878 } else if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha512Guid)) {
879 HashAlg = HASHALG_SHA512;
880 } else {
881 DbxSize -= DbxList->SignatureListSize;
882 DbxList = (EFI_SIGNATURE_LIST *) ((UINT8 *) DbxList + DbxList->SignatureListSize);
883 continue;
884 }
885
886 //
887 // Calculate the hash value of current TBSCertificate for comparision.
888 //
889 if (mHash[HashAlg].GetContextSize == NULL) {
890 goto Done;
891 }
892 ZeroMem (CertDigest, MAX_DIGEST_SIZE);
893 HashCtx = AllocatePool (mHash[HashAlg].GetContextSize ());
894 if (HashCtx == NULL) {
895 goto Done;
896 }
897 Status = mHash[HashAlg].HashInit (HashCtx);
898 if (!Status) {
899 goto Done;
900 }
901 Status = mHash[HashAlg].HashUpdate (HashCtx, TBSCert, TBSCertSize);
902 if (!Status) {
903 goto Done;
904 }
905 Status = mHash[HashAlg].HashFinal (HashCtx, CertDigest);
906 if (!Status) {
907 goto Done;
908 }
909
910 SiglistHeaderSize = sizeof (EFI_SIGNATURE_LIST) + DbxList->SignatureHeaderSize;
911 CertHash = (EFI_SIGNATURE_DATA *) ((UINT8 *) DbxList + SiglistHeaderSize);
912 CertHashCount = (DbxList->SignatureListSize - SiglistHeaderSize) / DbxList->SignatureSize;
913 for (Index = 0; Index < CertHashCount; Index++) {
914 //
915 // Iterate each Signature Data Node within this CertList for verify.
916 //
917 DbxCertHash = CertHash->SignatureData;
918 if (CompareMem (DbxCertHash, CertDigest, mHash[HashAlg].DigestLength) == 0) {
919 //
920 // Hash of Certificate is found in forbidden database.
921 //
922 IsFound = TRUE;
923
924 //
925 // Return the revocation time.
926 //
927 CopyMem (RevocationTime, (EFI_TIME *)(DbxCertHash + mHash[HashAlg].DigestLength), sizeof (EFI_TIME));
928 goto Done;
929 }
930 CertHash = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertHash + DbxList->SignatureSize);
931 }
932
933 DbxSize -= DbxList->SignatureListSize;
934 DbxList = (EFI_SIGNATURE_LIST *) ((UINT8 *) DbxList + DbxList->SignatureListSize);
935 }
936
937 Done:
938 if (HashCtx != NULL) {
939 FreePool (HashCtx);
940 }
941
942 return IsFound;
943 }
944
945 /**
946 Check whether signature is in specified database.
947
948 @param[in] VariableName Name of database variable that is searched in.
949 @param[in] Signature Pointer to signature that is searched for.
950 @param[in] CertType Pointer to hash algorithm.
951 @param[in] SignatureSize Size of Signature.
952
953 @return TRUE Found the signature in the variable database.
954 @return FALSE Not found the signature in the variable database.
955
956 **/
957 BOOLEAN
958 IsSignatureFoundInDatabase (
959 IN CHAR16 *VariableName,
960 IN UINT8 *Signature,
961 IN EFI_GUID *CertType,
962 IN UINTN SignatureSize
963 )
964 {
965 EFI_STATUS Status;
966 EFI_SIGNATURE_LIST *CertList;
967 EFI_SIGNATURE_DATA *Cert;
968 UINTN DataSize;
969 UINT8 *Data;
970 UINTN Index;
971 UINTN CertCount;
972 BOOLEAN IsFound;
973
974 //
975 // Read signature database variable.
976 //
977 IsFound = FALSE;
978 Data = NULL;
979 DataSize = 0;
980 Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
981 if (Status != EFI_BUFFER_TOO_SMALL) {
982 return FALSE;
983 }
984
985 Data = (UINT8 *) AllocateZeroPool (DataSize);
986 if (Data == NULL) {
987 return FALSE;
988 }
989
990 Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, Data);
991 if (EFI_ERROR (Status)) {
992 goto Done;
993 }
994 //
995 // Enumerate all signature data in SigDB to check if signature exists for executable.
996 //
997 CertList = (EFI_SIGNATURE_LIST *) Data;
998 while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
999 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1000 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1001 if ((CertList->SignatureSize == sizeof(EFI_SIGNATURE_DATA) - 1 + SignatureSize) && (CompareGuid(&CertList->SignatureType, CertType))) {
1002 for (Index = 0; Index < CertCount; Index++) {
1003 if (CompareMem (Cert->SignatureData, Signature, SignatureSize) == 0) {
1004 //
1005 // Find the signature in database.
1006 //
1007 IsFound = TRUE;
1008 //
1009 // Entries in UEFI_IMAGE_SECURITY_DATABASE that are used to validate image should be measured
1010 //
1011 if (StrCmp(VariableName, EFI_IMAGE_SECURITY_DATABASE) == 0) {
1012 SecureBootHook (VariableName, &gEfiImageSecurityDatabaseGuid, CertList->SignatureSize, Cert);
1013 }
1014 break;
1015 }
1016
1017 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
1018 }
1019
1020 if (IsFound) {
1021 break;
1022 }
1023 }
1024
1025 DataSize -= CertList->SignatureListSize;
1026 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1027 }
1028
1029 Done:
1030 if (Data != NULL) {
1031 FreePool (Data);
1032 }
1033
1034 return IsFound;
1035 }
1036
1037 /**
1038 Check whether the timestamp is valid by comparing the signing time and the revocation time.
1039
1040 @param SigningTime A pointer to the signing time.
1041 @param RevocationTime A pointer to the revocation time.
1042
1043 @retval TRUE The SigningTime is not later than the RevocationTime.
1044 @retval FALSE The SigningTime is later than the RevocationTime.
1045
1046 **/
1047 BOOLEAN
1048 IsValidSignatureByTimestamp (
1049 IN EFI_TIME *SigningTime,
1050 IN EFI_TIME *RevocationTime
1051 )
1052 {
1053 if (SigningTime->Year != RevocationTime->Year) {
1054 return (BOOLEAN) (SigningTime->Year < RevocationTime->Year);
1055 } else if (SigningTime->Month != RevocationTime->Month) {
1056 return (BOOLEAN) (SigningTime->Month < RevocationTime->Month);
1057 } else if (SigningTime->Day != RevocationTime->Day) {
1058 return (BOOLEAN) (SigningTime->Day < RevocationTime->Day);
1059 } else if (SigningTime->Hour != RevocationTime->Hour) {
1060 return (BOOLEAN) (SigningTime->Hour < RevocationTime->Hour);
1061 } else if (SigningTime->Minute != RevocationTime->Minute) {
1062 return (BOOLEAN) (SigningTime->Minute < RevocationTime->Minute);
1063 }
1064
1065 return (BOOLEAN) (SigningTime->Second <= RevocationTime->Second);
1066 }
1067
1068 /**
1069 Check if the given time value is zero.
1070
1071 @param[in] Time Pointer of a time value.
1072
1073 @retval TRUE The Time is Zero.
1074 @retval FALSE The Time is not Zero.
1075
1076 **/
1077 BOOLEAN
1078 IsTimeZero (
1079 IN EFI_TIME *Time
1080 )
1081 {
1082 if ((Time->Year == 0) && (Time->Month == 0) && (Time->Day == 0) &&
1083 (Time->Hour == 0) && (Time->Minute == 0) && (Time->Second == 0)) {
1084 return TRUE;
1085 }
1086
1087 return FALSE;
1088 }
1089
1090 /**
1091 Check whether the timestamp signature is valid and the signing time is also earlier than
1092 the revocation time.
1093
1094 @param[in] AuthData Pointer to the Authenticode signature retrieved from signed image.
1095 @param[in] AuthDataSize Size of the Authenticode signature in bytes.
1096 @param[in] RevocationTime The time that the certificate was revoked.
1097
1098 @retval TRUE Timestamp signature is valid and signing time is no later than the
1099 revocation time.
1100 @retval FALSE Timestamp signature is not valid or the signing time is later than the
1101 revocation time.
1102
1103 **/
1104 BOOLEAN
1105 PassTimestampCheck (
1106 IN UINT8 *AuthData,
1107 IN UINTN AuthDataSize,
1108 IN EFI_TIME *RevocationTime
1109 )
1110 {
1111 EFI_STATUS Status;
1112 BOOLEAN VerifyStatus;
1113 EFI_SIGNATURE_LIST *CertList;
1114 EFI_SIGNATURE_DATA *Cert;
1115 UINT8 *DbtData;
1116 UINTN DbtDataSize;
1117 UINT8 *RootCert;
1118 UINTN RootCertSize;
1119 UINTN Index;
1120 UINTN CertCount;
1121 EFI_TIME SigningTime;
1122
1123 //
1124 // Variable Initialization
1125 //
1126 VerifyStatus = FALSE;
1127 DbtData = NULL;
1128 CertList = NULL;
1129 Cert = NULL;
1130 RootCert = NULL;
1131 RootCertSize = 0;
1132
1133 //
1134 // If RevocationTime is zero, the certificate shall be considered to always be revoked.
1135 //
1136 if (IsTimeZero (RevocationTime)) {
1137 return FALSE;
1138 }
1139
1140 //
1141 // RevocationTime is non-zero, the certificate should be considered to be revoked from that time and onwards.
1142 // Using the dbt to get the trusted TSA certificates.
1143 //
1144 DbtDataSize = 0;
1145 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE2, &gEfiImageSecurityDatabaseGuid, NULL, &DbtDataSize, NULL);
1146 if (Status != EFI_BUFFER_TOO_SMALL) {
1147 goto Done;
1148 }
1149 DbtData = (UINT8 *) AllocateZeroPool (DbtDataSize);
1150 if (DbtData == NULL) {
1151 goto Done;
1152 }
1153 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE2, &gEfiImageSecurityDatabaseGuid, NULL, &DbtDataSize, (VOID *) DbtData);
1154 if (EFI_ERROR (Status)) {
1155 goto Done;
1156 }
1157
1158 CertList = (EFI_SIGNATURE_LIST *) DbtData;
1159 while ((DbtDataSize > 0) && (DbtDataSize >= CertList->SignatureListSize)) {
1160 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
1161 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1162 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1163 for (Index = 0; Index < CertCount; Index++) {
1164 //
1165 // Iterate each Signature Data Node within this CertList for verify.
1166 //
1167 RootCert = Cert->SignatureData;
1168 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
1169 //
1170 // Get the signing time if the timestamp signature is valid.
1171 //
1172 if (ImageTimestampVerify (AuthData, AuthDataSize, RootCert, RootCertSize, &SigningTime)) {
1173 //
1174 // The signer signature is valid only when the signing time is earlier than revocation time.
1175 //
1176 if (IsValidSignatureByTimestamp (&SigningTime, RevocationTime)) {
1177 VerifyStatus = TRUE;
1178 goto Done;
1179 }
1180 }
1181 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
1182 }
1183 }
1184 DbtDataSize -= CertList->SignatureListSize;
1185 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1186 }
1187
1188 Done:
1189 if (DbtData != NULL) {
1190 FreePool (DbtData);
1191 }
1192
1193 return VerifyStatus;
1194 }
1195
1196 /**
1197 Check whether the image signature is forbidden by the forbidden database (dbx).
1198 The image is forbidden to load if any certificates for signing are revoked before signing time.
1199
1200 @param[in] AuthData Pointer to the Authenticode signature retrieved from the signed image.
1201 @param[in] AuthDataSize Size of the Authenticode signature in bytes.
1202
1203 @retval TRUE Image is forbidden by dbx.
1204 @retval FALSE Image is not forbidden by dbx.
1205
1206 **/
1207 BOOLEAN
1208 IsForbiddenByDbx (
1209 IN UINT8 *AuthData,
1210 IN UINTN AuthDataSize
1211 )
1212 {
1213 EFI_STATUS Status;
1214 BOOLEAN IsForbidden;
1215 UINT8 *Data;
1216 UINTN DataSize;
1217 EFI_SIGNATURE_LIST *CertList;
1218 UINTN CertListSize;
1219 EFI_SIGNATURE_DATA *CertData;
1220 UINT8 *RootCert;
1221 UINTN RootCertSize;
1222 UINTN CertCount;
1223 UINTN Index;
1224 UINT8 *CertBuffer;
1225 UINTN BufferLength;
1226 UINT8 *TrustedCert;
1227 UINTN TrustedCertLength;
1228 UINT8 CertNumber;
1229 UINT8 *CertPtr;
1230 UINT8 *Cert;
1231 UINTN CertSize;
1232 EFI_TIME RevocationTime;
1233 //
1234 // Variable Initialization
1235 //
1236 IsForbidden = FALSE;
1237 Data = NULL;
1238 CertList = NULL;
1239 CertData = NULL;
1240 RootCert = NULL;
1241 RootCertSize = 0;
1242 Cert = NULL;
1243 CertBuffer = NULL;
1244 BufferLength = 0;
1245 TrustedCert = NULL;
1246 TrustedCertLength = 0;
1247
1248 //
1249 // The image will not be forbidden if dbx can't be got.
1250 //
1251 DataSize = 0;
1252 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
1253 if (Status != EFI_BUFFER_TOO_SMALL) {
1254 return IsForbidden;
1255 }
1256 Data = (UINT8 *) AllocateZeroPool (DataSize);
1257 if (Data == NULL) {
1258 return IsForbidden;
1259 }
1260
1261 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data);
1262 if (EFI_ERROR (Status)) {
1263 return IsForbidden;
1264 }
1265
1266 //
1267 // Verify image signature with RAW X509 certificates in DBX database.
1268 // If passed, the image will be forbidden.
1269 //
1270 CertList = (EFI_SIGNATURE_LIST *) Data;
1271 CertListSize = DataSize;
1272 while ((CertListSize > 0) && (CertListSize >= CertList->SignatureListSize)) {
1273 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
1274 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1275 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1276
1277 for (Index = 0; Index < CertCount; Index++) {
1278 //
1279 // Iterate each Signature Data Node within this CertList for verify.
1280 //
1281 RootCert = CertData->SignatureData;
1282 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
1283
1284 //
1285 // Call AuthenticodeVerify library to Verify Authenticode struct.
1286 //
1287 IsForbidden = AuthenticodeVerify (
1288 AuthData,
1289 AuthDataSize,
1290 RootCert,
1291 RootCertSize,
1292 mImageDigest,
1293 mImageDigestSize
1294 );
1295 if (IsForbidden) {
1296 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature is forbidden by DBX.\n"));
1297 goto Done;
1298 }
1299
1300 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize);
1301 }
1302 }
1303
1304 CertListSize -= CertList->SignatureListSize;
1305 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1306 }
1307
1308 //
1309 // Check X.509 Certificate Hash & Possible Timestamp.
1310 //
1311
1312 //
1313 // Retrieve the certificate stack from AuthData
1314 // The output CertStack format will be:
1315 // UINT8 CertNumber;
1316 // UINT32 Cert1Length;
1317 // UINT8 Cert1[];
1318 // UINT32 Cert2Length;
1319 // UINT8 Cert2[];
1320 // ...
1321 // UINT32 CertnLength;
1322 // UINT8 Certn[];
1323 //
1324 Pkcs7GetSigners (AuthData, AuthDataSize, &CertBuffer, &BufferLength, &TrustedCert, &TrustedCertLength);
1325 if ((BufferLength == 0) || (CertBuffer == NULL)) {
1326 IsForbidden = TRUE;
1327 goto Done;
1328 }
1329
1330 //
1331 // Check if any hash of certificates embedded in AuthData is in the forbidden database.
1332 //
1333 CertNumber = (UINT8) (*CertBuffer);
1334 CertPtr = CertBuffer + 1;
1335 for (Index = 0; Index < CertNumber; Index++) {
1336 CertSize = (UINTN) ReadUnaligned32 ((UINT32 *)CertPtr);
1337 Cert = (UINT8 *)CertPtr + sizeof (UINT32);
1338 //
1339 // Advance CertPtr to the next cert in image signer's cert list
1340 //
1341 CertPtr = CertPtr + sizeof (UINT32) + CertSize;
1342
1343 if (IsCertHashFoundInDatabase (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data, DataSize, &RevocationTime)) {
1344 //
1345 // Check the timestamp signature and signing time to determine if the image can be trusted.
1346 //
1347 IsForbidden = TRUE;
1348 if (PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime)) {
1349 IsForbidden = FALSE;
1350 //
1351 // Pass DBT check. Continue to check other certs in image signer's cert list against DBX, DBT
1352 //
1353 continue;
1354 }
1355 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature failed the timestamp check.\n"));
1356 goto Done;
1357 }
1358
1359 }
1360
1361 Done:
1362 if (Data != NULL) {
1363 FreePool (Data);
1364 }
1365
1366 Pkcs7FreeSigners (CertBuffer);
1367 Pkcs7FreeSigners (TrustedCert);
1368
1369 return IsForbidden;
1370 }
1371
1372
1373 /**
1374 Check whether the image signature can be verified by the trusted certificates in DB database.
1375
1376 @param[in] AuthData Pointer to the Authenticode signature retrieved from signed image.
1377 @param[in] AuthDataSize Size of the Authenticode signature in bytes.
1378
1379 @retval TRUE Image passed verification using certificate in db.
1380 @retval FALSE Image didn't pass verification using certificate in db.
1381
1382 **/
1383 BOOLEAN
1384 IsAllowedByDb (
1385 IN UINT8 *AuthData,
1386 IN UINTN AuthDataSize
1387 )
1388 {
1389 EFI_STATUS Status;
1390 BOOLEAN VerifyStatus;
1391 EFI_SIGNATURE_LIST *CertList;
1392 EFI_SIGNATURE_DATA *CertData;
1393 UINTN DataSize;
1394 UINT8 *Data;
1395 UINT8 *RootCert;
1396 UINTN RootCertSize;
1397 UINTN Index;
1398 UINTN CertCount;
1399 UINTN DbxDataSize;
1400 UINT8 *DbxData;
1401 EFI_TIME RevocationTime;
1402
1403 Data = NULL;
1404 CertList = NULL;
1405 CertData = NULL;
1406 RootCert = NULL;
1407 DbxData = NULL;
1408 RootCertSize = 0;
1409 VerifyStatus = FALSE;
1410
1411 DataSize = 0;
1412 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
1413 if (Status == EFI_BUFFER_TOO_SMALL) {
1414 Data = (UINT8 *) AllocateZeroPool (DataSize);
1415 if (Data == NULL) {
1416 return VerifyStatus;
1417 }
1418
1419 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data);
1420 if (EFI_ERROR (Status)) {
1421 goto Done;
1422 }
1423
1424 //
1425 // Find X509 certificate in Signature List to verify the signature in pkcs7 signed data.
1426 //
1427 CertList = (EFI_SIGNATURE_LIST *) Data;
1428 while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
1429 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
1430 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1431 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1432
1433 for (Index = 0; Index < CertCount; Index++) {
1434 //
1435 // Iterate each Signature Data Node within this CertList for verify.
1436 //
1437 RootCert = CertData->SignatureData;
1438 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
1439
1440 //
1441 // Call AuthenticodeVerify library to Verify Authenticode struct.
1442 //
1443 VerifyStatus = AuthenticodeVerify (
1444 AuthData,
1445 AuthDataSize,
1446 RootCert,
1447 RootCertSize,
1448 mImageDigest,
1449 mImageDigestSize
1450 );
1451 if (VerifyStatus) {
1452 //
1453 // Here We still need to check if this RootCert's Hash is revoked
1454 //
1455 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, NULL);
1456 if (Status == EFI_BUFFER_TOO_SMALL) {
1457 goto Done;
1458 }
1459 DbxData = (UINT8 *) AllocateZeroPool (DbxDataSize);
1460 if (DbxData == NULL) {
1461 goto Done;
1462 }
1463
1464 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, (VOID *) DbxData);
1465 if (EFI_ERROR (Status)) {
1466 goto Done;
1467 }
1468
1469 if (IsCertHashFoundInDatabase (RootCert, RootCertSize, (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime)) {
1470 //
1471 // Check the timestamp signature and signing time to determine if the RootCert can be trusted.
1472 //
1473 VerifyStatus = PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime);
1474 if (!VerifyStatus) {
1475 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed and signature is accepted by DB, but its root cert failed the timestamp check.\n"));
1476 }
1477 }
1478
1479 goto Done;
1480 }
1481
1482 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize);
1483 }
1484 }
1485
1486 DataSize -= CertList->SignatureListSize;
1487 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1488 }
1489 }
1490
1491 Done:
1492
1493 if (VerifyStatus) {
1494 SecureBootHook (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, CertList->SignatureSize, CertData);
1495 }
1496
1497 if (Data != NULL) {
1498 FreePool (Data);
1499 }
1500 if (DbxData != NULL) {
1501 FreePool (DbxData);
1502 }
1503
1504 return VerifyStatus;
1505 }
1506
1507 /**
1508 Provide verification service for signed images, which include both signature validation
1509 and platform policy control. For signature types, both UEFI WIN_CERTIFICATE_UEFI_GUID and
1510 MSFT Authenticode type signatures are supported.
1511
1512 In this implementation, only verify external executables when in USER MODE.
1513 Executables from FV is bypass, so pass in AuthenticationStatus is ignored.
1514
1515 The image verification policy is:
1516 If the image is signed,
1517 At least one valid signature or at least one hash value of the image must match a record
1518 in the security database "db", and no valid signature nor any hash value of the image may
1519 be reflected in the security database "dbx".
1520 Otherwise, the image is not signed,
1521 The SHA256 hash value of the image must match a record in the security database "db", and
1522 not be reflected in the security data base "dbx".
1523
1524 Caution: This function may receive untrusted input.
1525 PE/COFF image is external input, so this function will validate its data structure
1526 within this image buffer before use.
1527
1528 @param[in] AuthenticationStatus
1529 This is the authentication status returned from the security
1530 measurement services for the input file.
1531 @param[in] File This is a pointer to the device path of the file that is
1532 being dispatched. This will optionally be used for logging.
1533 @param[in] FileBuffer File buffer matches the input file device path.
1534 @param[in] FileSize Size of File buffer matches the input file device path.
1535 @param[in] BootPolicy A boot policy that was used to call LoadImage() UEFI service.
1536
1537 @retval EFI_SUCCESS The file specified by DevicePath and non-NULL
1538 FileBuffer did authenticate, and the platform policy dictates
1539 that the DXE Foundation may use the file.
1540 @retval EFI_SUCCESS The device path specified by NULL device path DevicePath
1541 and non-NULL FileBuffer did authenticate, and the platform
1542 policy dictates that the DXE Foundation may execute the image in
1543 FileBuffer.
1544 @retval EFI_SECURITY_VIOLATION The file specified by File did not authenticate, and
1545 the platform policy dictates that File should be placed
1546 in the untrusted state. The image has been added to the file
1547 execution table.
1548 @retval EFI_ACCESS_DENIED The file specified by File and FileBuffer did not
1549 authenticate, and the platform policy dictates that the DXE
1550 Foundation many not use File.
1551
1552 **/
1553 EFI_STATUS
1554 EFIAPI
1555 DxeImageVerificationHandler (
1556 IN UINT32 AuthenticationStatus,
1557 IN CONST EFI_DEVICE_PATH_PROTOCOL *File,
1558 IN VOID *FileBuffer,
1559 IN UINTN FileSize,
1560 IN BOOLEAN BootPolicy
1561 )
1562 {
1563 EFI_IMAGE_DOS_HEADER *DosHdr;
1564 BOOLEAN IsVerified;
1565 EFI_SIGNATURE_LIST *SignatureList;
1566 UINTN SignatureListSize;
1567 EFI_SIGNATURE_DATA *Signature;
1568 EFI_IMAGE_EXECUTION_ACTION Action;
1569 WIN_CERTIFICATE *WinCertificate;
1570 UINT32 Policy;
1571 UINT8 *SecureBoot;
1572 PE_COFF_LOADER_IMAGE_CONTEXT ImageContext;
1573 UINT32 NumberOfRvaAndSizes;
1574 WIN_CERTIFICATE_EFI_PKCS *PkcsCertData;
1575 WIN_CERTIFICATE_UEFI_GUID *WinCertUefiGuid;
1576 UINT8 *AuthData;
1577 UINTN AuthDataSize;
1578 EFI_IMAGE_DATA_DIRECTORY *SecDataDir;
1579 UINT32 OffSet;
1580 CHAR16 *NameStr;
1581 RETURN_STATUS PeCoffStatus;
1582 EFI_STATUS HashStatus;
1583
1584 SignatureList = NULL;
1585 SignatureListSize = 0;
1586 WinCertificate = NULL;
1587 SecDataDir = NULL;
1588 PkcsCertData = NULL;
1589 Action = EFI_IMAGE_EXECUTION_AUTH_UNTESTED;
1590 IsVerified = FALSE;
1591
1592
1593 //
1594 // Check the image type and get policy setting.
1595 //
1596 switch (GetImageType (File)) {
1597
1598 case IMAGE_FROM_FV:
1599 Policy = ALWAYS_EXECUTE;
1600 break;
1601
1602 case IMAGE_FROM_OPTION_ROM:
1603 Policy = PcdGet32 (PcdOptionRomImageVerificationPolicy);
1604 break;
1605
1606 case IMAGE_FROM_REMOVABLE_MEDIA:
1607 Policy = PcdGet32 (PcdRemovableMediaImageVerificationPolicy);
1608 break;
1609
1610 case IMAGE_FROM_FIXED_MEDIA:
1611 Policy = PcdGet32 (PcdFixedMediaImageVerificationPolicy);
1612 break;
1613
1614 default:
1615 Policy = DENY_EXECUTE_ON_SECURITY_VIOLATION;
1616 break;
1617 }
1618 //
1619 // If policy is always/never execute, return directly.
1620 //
1621 if (Policy == ALWAYS_EXECUTE) {
1622 return EFI_SUCCESS;
1623 }
1624 if (Policy == NEVER_EXECUTE) {
1625 return EFI_ACCESS_DENIED;
1626 }
1627
1628 //
1629 // The policy QUERY_USER_ON_SECURITY_VIOLATION and ALLOW_EXECUTE_ON_SECURITY_VIOLATION
1630 // violates the UEFI spec and has been removed.
1631 //
1632 ASSERT (Policy != QUERY_USER_ON_SECURITY_VIOLATION && Policy != ALLOW_EXECUTE_ON_SECURITY_VIOLATION);
1633 if (Policy == QUERY_USER_ON_SECURITY_VIOLATION || Policy == ALLOW_EXECUTE_ON_SECURITY_VIOLATION) {
1634 CpuDeadLoop ();
1635 }
1636
1637 GetEfiGlobalVariable2 (EFI_SECURE_BOOT_MODE_NAME, (VOID**)&SecureBoot, NULL);
1638 //
1639 // Skip verification if SecureBoot variable doesn't exist.
1640 //
1641 if (SecureBoot == NULL) {
1642 return EFI_SUCCESS;
1643 }
1644
1645 //
1646 // Skip verification if SecureBoot is disabled but not AuditMode
1647 //
1648 if (*SecureBoot == SECURE_BOOT_MODE_DISABLE) {
1649 FreePool (SecureBoot);
1650 return EFI_SUCCESS;
1651 }
1652 FreePool (SecureBoot);
1653
1654 //
1655 // Read the Dos header.
1656 //
1657 if (FileBuffer == NULL) {
1658 return EFI_ACCESS_DENIED;
1659 }
1660
1661 mImageBase = (UINT8 *) FileBuffer;
1662 mImageSize = FileSize;
1663
1664 ZeroMem (&ImageContext, sizeof (ImageContext));
1665 ImageContext.Handle = (VOID *) FileBuffer;
1666 ImageContext.ImageRead = (PE_COFF_LOADER_READ_FILE) DxeImageVerificationLibImageRead;
1667
1668 //
1669 // Get information about the image being loaded
1670 //
1671 PeCoffStatus = PeCoffLoaderGetImageInfo (&ImageContext);
1672 if (RETURN_ERROR (PeCoffStatus)) {
1673 //
1674 // The information can't be got from the invalid PeImage
1675 //
1676 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: PeImage invalid. Cannot retrieve image information.\n"));
1677 goto Failed;
1678 }
1679
1680 DosHdr = (EFI_IMAGE_DOS_HEADER *) mImageBase;
1681 if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) {
1682 //
1683 // DOS image header is present,
1684 // so read the PE header after the DOS image header.
1685 //
1686 mPeCoffHeaderOffset = DosHdr->e_lfanew;
1687 } else {
1688 mPeCoffHeaderOffset = 0;
1689 }
1690 //
1691 // Check PE/COFF image.
1692 //
1693 mNtHeader.Pe32 = (EFI_IMAGE_NT_HEADERS32 *) (mImageBase + mPeCoffHeaderOffset);
1694 if (mNtHeader.Pe32->Signature != EFI_IMAGE_NT_SIGNATURE) {
1695 //
1696 // It is not a valid Pe/Coff file.
1697 //
1698 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Not a valid PE/COFF image.\n"));
1699 goto Failed;
1700 }
1701
1702 if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
1703 //
1704 // Use PE32 offset.
1705 //
1706 NumberOfRvaAndSizes = mNtHeader.Pe32->OptionalHeader.NumberOfRvaAndSizes;
1707 if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
1708 SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
1709 }
1710 } else {
1711 //
1712 // Use PE32+ offset.
1713 //
1714 NumberOfRvaAndSizes = mNtHeader.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes;
1715 if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
1716 SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
1717 }
1718 }
1719
1720 //
1721 // Start Image Validation.
1722 //
1723 if (SecDataDir == NULL || SecDataDir->Size == 0) {
1724 //
1725 // This image is not signed. The SHA256 hash value of the image must match a record in the security database "db",
1726 // and not be reflected in the security data base "dbx".
1727 //
1728 if (!HashPeImage (HASHALG_SHA256)) {
1729 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Failed to hash this image using %s.\n", mHashTypeStr));
1730 goto Failed;
1731 }
1732
1733 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) {
1734 //
1735 // Image Hash is in forbidden database (DBX).
1736 //
1737 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is not signed and %s hash of image is forbidden by DBX.\n", mHashTypeStr));
1738 goto Failed;
1739 }
1740
1741 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) {
1742 //
1743 // Image Hash is in allowed database (DB).
1744 //
1745 return EFI_SUCCESS;
1746 }
1747
1748 //
1749 // Image Hash is not found in both forbidden and allowed database.
1750 //
1751 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is not signed and %s hash of image is not found in DB/DBX.\n", mHashTypeStr));
1752 goto Failed;
1753 }
1754
1755 //
1756 // Verify the signature of the image, multiple signatures are allowed as per PE/COFF Section 4.7
1757 // "Attribute Certificate Table".
1758 // The first certificate starts at offset (SecDataDir->VirtualAddress) from the start of the file.
1759 //
1760 for (OffSet = SecDataDir->VirtualAddress;
1761 OffSet < (SecDataDir->VirtualAddress + SecDataDir->Size);
1762 OffSet += (WinCertificate->dwLength + ALIGN_SIZE (WinCertificate->dwLength))) {
1763 WinCertificate = (WIN_CERTIFICATE *) (mImageBase + OffSet);
1764 if ((SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) <= sizeof (WIN_CERTIFICATE) ||
1765 (SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) < WinCertificate->dwLength) {
1766 break;
1767 }
1768
1769 //
1770 // Verify the image's Authenticode signature, only DER-encoded PKCS#7 signed data is supported.
1771 //
1772 if (WinCertificate->wCertificateType == WIN_CERT_TYPE_PKCS_SIGNED_DATA) {
1773 //
1774 // The certificate is formatted as WIN_CERTIFICATE_EFI_PKCS which is described in the
1775 // Authenticode specification.
1776 //
1777 PkcsCertData = (WIN_CERTIFICATE_EFI_PKCS *) WinCertificate;
1778 if (PkcsCertData->Hdr.dwLength <= sizeof (PkcsCertData->Hdr)) {
1779 break;
1780 }
1781 AuthData = PkcsCertData->CertData;
1782 AuthDataSize = PkcsCertData->Hdr.dwLength - sizeof(PkcsCertData->Hdr);
1783 } else if (WinCertificate->wCertificateType == WIN_CERT_TYPE_EFI_GUID) {
1784 //
1785 // The certificate is formatted as WIN_CERTIFICATE_UEFI_GUID which is described in UEFI Spec.
1786 //
1787 WinCertUefiGuid = (WIN_CERTIFICATE_UEFI_GUID *) WinCertificate;
1788 if (WinCertUefiGuid->Hdr.dwLength <= OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData)) {
1789 break;
1790 }
1791 if (!CompareGuid (&WinCertUefiGuid->CertType, &gEfiCertPkcs7Guid)) {
1792 continue;
1793 }
1794 AuthData = WinCertUefiGuid->CertData;
1795 AuthDataSize = WinCertUefiGuid->Hdr.dwLength - OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData);
1796 } else {
1797 if (WinCertificate->dwLength < sizeof (WIN_CERTIFICATE)) {
1798 break;
1799 }
1800 continue;
1801 }
1802
1803 HashStatus = HashPeImageByType (AuthData, AuthDataSize);
1804 if (EFI_ERROR (HashStatus)) {
1805 continue;
1806 }
1807
1808 //
1809 // Check the digital signature against the revoked certificate in forbidden database (dbx).
1810 //
1811 if (IsForbiddenByDbx (AuthData, AuthDataSize)) {
1812 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED;
1813 IsVerified = FALSE;
1814 break;
1815 }
1816
1817 //
1818 // Check the digital signature against the valid certificate in allowed database (db).
1819 //
1820 if (!IsVerified) {
1821 if (IsAllowedByDb (AuthData, AuthDataSize)) {
1822 IsVerified = TRUE;
1823 }
1824 }
1825
1826 //
1827 // Check the image's hash value.
1828 //
1829 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) {
1830 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND;
1831 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but %s hash of image is found in DBX.\n", mHashTypeStr));
1832 IsVerified = FALSE;
1833 break;
1834 }
1835 if (!IsVerified) {
1836 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) {
1837 IsVerified = TRUE;
1838 } else {
1839 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));
1840 }
1841 }
1842 }
1843
1844 if (OffSet != (SecDataDir->VirtualAddress + SecDataDir->Size)) {
1845 //
1846 // The Size in Certificate Table or the attribute certificate table is corrupted.
1847 //
1848 IsVerified = FALSE;
1849 }
1850
1851 if (IsVerified) {
1852 return EFI_SUCCESS;
1853 }
1854 if (Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED || Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND) {
1855 //
1856 // Get image hash value as signature of executable.
1857 //
1858 SignatureListSize = sizeof (EFI_SIGNATURE_LIST) + sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize;
1859 SignatureList = (EFI_SIGNATURE_LIST *) AllocateZeroPool (SignatureListSize);
1860 if (SignatureList == NULL) {
1861 goto Failed;
1862 }
1863 SignatureList->SignatureHeaderSize = 0;
1864 SignatureList->SignatureListSize = (UINT32) SignatureListSize;
1865 SignatureList->SignatureSize = (UINT32) (sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize);
1866 CopyMem (&SignatureList->SignatureType, &mCertType, sizeof (EFI_GUID));
1867 Signature = (EFI_SIGNATURE_DATA *) ((UINT8 *) SignatureList + sizeof (EFI_SIGNATURE_LIST));
1868 CopyMem (Signature->SignatureData, mImageDigest, mImageDigestSize);
1869 }
1870
1871 Failed:
1872 //
1873 // Policy decides to defer or reject the image; add its information in image executable information table.
1874 //
1875 NameStr = ConvertDevicePathToText (File, FALSE, TRUE);
1876 AddImageExeInfo (Action, NameStr, File, SignatureList, SignatureListSize);
1877 if (NameStr != NULL) {
1878 DEBUG ((DEBUG_INFO, "The image doesn't pass verification: %s\n", NameStr));
1879 FreePool(NameStr);
1880 }
1881
1882 if (SignatureList != NULL) {
1883 FreePool (SignatureList);
1884 }
1885
1886 return EFI_SECURITY_VIOLATION;
1887 }
1888
1889 /**
1890 On Ready To Boot Services Event notification handler.
1891
1892 Add the image execution information table if it is not in system configuration table.
1893
1894 @param[in] Event Event whose notification function is being invoked
1895 @param[in] Context Pointer to the notification function's context
1896
1897 **/
1898 VOID
1899 EFIAPI
1900 OnReadyToBoot (
1901 IN EFI_EVENT Event,
1902 IN VOID *Context
1903 )
1904 {
1905 EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable;
1906 UINTN ImageExeInfoTableSize;
1907
1908 EfiGetSystemConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID **) &ImageExeInfoTable);
1909 if (ImageExeInfoTable != NULL) {
1910 return;
1911 }
1912
1913 ImageExeInfoTableSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE);
1914 ImageExeInfoTable = (EFI_IMAGE_EXECUTION_INFO_TABLE *) AllocateRuntimePool (ImageExeInfoTableSize);
1915 if (ImageExeInfoTable == NULL) {
1916 return ;
1917 }
1918
1919 ImageExeInfoTable->NumberOfImages = 0;
1920 gBS->InstallConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID *) ImageExeInfoTable);
1921
1922 }
1923
1924 /**
1925 Register security measurement handler.
1926
1927 @param ImageHandle ImageHandle of the loaded driver.
1928 @param SystemTable Pointer to the EFI System Table.
1929
1930 @retval EFI_SUCCESS The handlers were registered successfully.
1931 **/
1932 EFI_STATUS
1933 EFIAPI
1934 DxeImageVerificationLibConstructor (
1935 IN EFI_HANDLE ImageHandle,
1936 IN EFI_SYSTEM_TABLE *SystemTable
1937 )
1938 {
1939 EFI_EVENT Event;
1940
1941 //
1942 // Register the event to publish the image execution table.
1943 //
1944 EfiCreateEventReadyToBootEx (
1945 TPL_CALLBACK,
1946 OnReadyToBoot,
1947 NULL,
1948 &Event
1949 );
1950
1951 return RegisterSecurity2Handler (
1952 DxeImageVerificationHandler,
1953 EFI_AUTH_OPERATION_VERIFY_IMAGE | EFI_AUTH_OPERATION_IMAGE_REQUIRED
1954 );
1955 }
EFI Development Kit II mirror for PVE