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SecurityPkg/DxeImageVerificationHandler: fix "defer" vs. "deny" policies
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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 SiglistHeaderSize = sizeof (EFI_SIGNATURE_LIST) + DbxList->SignatureHeaderSize;
912 CertHash = (EFI_SIGNATURE_DATA *) ((UINT8 *) DbxList + SiglistHeaderSize);
913 CertHashCount = (DbxList->SignatureListSize - SiglistHeaderSize) / DbxList->SignatureSize;
914 for (Index = 0; Index < CertHashCount; Index++) {
915 //
916 // Iterate each Signature Data Node within this CertList for verify.
917 //
918 DbxCertHash = CertHash->SignatureData;
919 if (CompareMem (DbxCertHash, CertDigest, mHash[HashAlg].DigestLength) == 0) {
920 //
921 // Hash of Certificate is found in forbidden database.
922 //
923 IsFound = TRUE;
924
925 //
926 // Return the revocation time.
927 //
928 CopyMem (RevocationTime, (EFI_TIME *)(DbxCertHash + mHash[HashAlg].DigestLength), sizeof (EFI_TIME));
929 goto Done;
930 }
931 CertHash = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertHash + DbxList->SignatureSize);
932 }
933
934 DbxSize -= DbxList->SignatureListSize;
935 DbxList = (EFI_SIGNATURE_LIST *) ((UINT8 *) DbxList + DbxList->SignatureListSize);
936 }
937
938 Done:
939 if (HashCtx != NULL) {
940 FreePool (HashCtx);
941 }
942
943 return IsFound;
944 }
945
946 /**
947 Check whether signature is in specified database.
948
949 @param[in] VariableName Name of database variable that is searched in.
950 @param[in] Signature Pointer to signature that is searched for.
951 @param[in] CertType Pointer to hash algorithm.
952 @param[in] SignatureSize Size of Signature.
953
954 @return TRUE Found the signature in the variable database.
955 @return FALSE Not found the signature in the variable database.
956
957 **/
958 BOOLEAN
959 IsSignatureFoundInDatabase (
960 IN CHAR16 *VariableName,
961 IN UINT8 *Signature,
962 IN EFI_GUID *CertType,
963 IN UINTN SignatureSize
964 )
965 {
966 EFI_STATUS Status;
967 EFI_SIGNATURE_LIST *CertList;
968 EFI_SIGNATURE_DATA *Cert;
969 UINTN DataSize;
970 UINT8 *Data;
971 UINTN Index;
972 UINTN CertCount;
973 BOOLEAN IsFound;
974
975 //
976 // Read signature database variable.
977 //
978 IsFound = FALSE;
979 Data = NULL;
980 DataSize = 0;
981 Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
982 if (Status != EFI_BUFFER_TOO_SMALL) {
983 return FALSE;
984 }
985
986 Data = (UINT8 *) AllocateZeroPool (DataSize);
987 if (Data == NULL) {
988 return FALSE;
989 }
990
991 Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, Data);
992 if (EFI_ERROR (Status)) {
993 goto Done;
994 }
995 //
996 // Enumerate all signature data in SigDB to check if signature exists for executable.
997 //
998 CertList = (EFI_SIGNATURE_LIST *) Data;
999 while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
1000 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1001 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1002 if ((CertList->SignatureSize == sizeof(EFI_SIGNATURE_DATA) - 1 + SignatureSize) && (CompareGuid(&CertList->SignatureType, CertType))) {
1003 for (Index = 0; Index < CertCount; Index++) {
1004 if (CompareMem (Cert->SignatureData, Signature, SignatureSize) == 0) {
1005 //
1006 // Find the signature in database.
1007 //
1008 IsFound = TRUE;
1009 //
1010 // Entries in UEFI_IMAGE_SECURITY_DATABASE that are used to validate image should be measured
1011 //
1012 if (StrCmp(VariableName, EFI_IMAGE_SECURITY_DATABASE) == 0) {
1013 SecureBootHook (VariableName, &gEfiImageSecurityDatabaseGuid, CertList->SignatureSize, Cert);
1014 }
1015 break;
1016 }
1017
1018 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
1019 }
1020
1021 if (IsFound) {
1022 break;
1023 }
1024 }
1025
1026 DataSize -= CertList->SignatureListSize;
1027 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1028 }
1029
1030 Done:
1031 if (Data != NULL) {
1032 FreePool (Data);
1033 }
1034
1035 return IsFound;
1036 }
1037
1038 /**
1039 Check whether the timestamp is valid by comparing the signing time and the revocation time.
1040
1041 @param SigningTime A pointer to the signing time.
1042 @param RevocationTime A pointer to the revocation time.
1043
1044 @retval TRUE The SigningTime is not later than the RevocationTime.
1045 @retval FALSE The SigningTime is later than the RevocationTime.
1046
1047 **/
1048 BOOLEAN
1049 IsValidSignatureByTimestamp (
1050 IN EFI_TIME *SigningTime,
1051 IN EFI_TIME *RevocationTime
1052 )
1053 {
1054 if (SigningTime->Year != RevocationTime->Year) {
1055 return (BOOLEAN) (SigningTime->Year < RevocationTime->Year);
1056 } else if (SigningTime->Month != RevocationTime->Month) {
1057 return (BOOLEAN) (SigningTime->Month < RevocationTime->Month);
1058 } else if (SigningTime->Day != RevocationTime->Day) {
1059 return (BOOLEAN) (SigningTime->Day < RevocationTime->Day);
1060 } else if (SigningTime->Hour != RevocationTime->Hour) {
1061 return (BOOLEAN) (SigningTime->Hour < RevocationTime->Hour);
1062 } else if (SigningTime->Minute != RevocationTime->Minute) {
1063 return (BOOLEAN) (SigningTime->Minute < RevocationTime->Minute);
1064 }
1065
1066 return (BOOLEAN) (SigningTime->Second <= RevocationTime->Second);
1067 }
1068
1069 /**
1070 Check if the given time value is zero.
1071
1072 @param[in] Time Pointer of a time value.
1073
1074 @retval TRUE The Time is Zero.
1075 @retval FALSE The Time is not Zero.
1076
1077 **/
1078 BOOLEAN
1079 IsTimeZero (
1080 IN EFI_TIME *Time
1081 )
1082 {
1083 if ((Time->Year == 0) && (Time->Month == 0) && (Time->Day == 0) &&
1084 (Time->Hour == 0) && (Time->Minute == 0) && (Time->Second == 0)) {
1085 return TRUE;
1086 }
1087
1088 return FALSE;
1089 }
1090
1091 /**
1092 Check whether the timestamp signature is valid and the signing time is also earlier than
1093 the revocation time.
1094
1095 @param[in] AuthData Pointer to the Authenticode signature retrieved from signed image.
1096 @param[in] AuthDataSize Size of the Authenticode signature in bytes.
1097 @param[in] RevocationTime The time that the certificate was revoked.
1098
1099 @retval TRUE Timestamp signature is valid and signing time is no later than the
1100 revocation time.
1101 @retval FALSE Timestamp signature is not valid or the signing time is later than the
1102 revocation time.
1103
1104 **/
1105 BOOLEAN
1106 PassTimestampCheck (
1107 IN UINT8 *AuthData,
1108 IN UINTN AuthDataSize,
1109 IN EFI_TIME *RevocationTime
1110 )
1111 {
1112 EFI_STATUS Status;
1113 BOOLEAN VerifyStatus;
1114 EFI_SIGNATURE_LIST *CertList;
1115 EFI_SIGNATURE_DATA *Cert;
1116 UINT8 *DbtData;
1117 UINTN DbtDataSize;
1118 UINT8 *RootCert;
1119 UINTN RootCertSize;
1120 UINTN Index;
1121 UINTN CertCount;
1122 EFI_TIME SigningTime;
1123
1124 //
1125 // Variable Initialization
1126 //
1127 VerifyStatus = FALSE;
1128 DbtData = NULL;
1129 CertList = NULL;
1130 Cert = NULL;
1131 RootCert = NULL;
1132 RootCertSize = 0;
1133
1134 //
1135 // If RevocationTime is zero, the certificate shall be considered to always be revoked.
1136 //
1137 if (IsTimeZero (RevocationTime)) {
1138 return FALSE;
1139 }
1140
1141 //
1142 // RevocationTime is non-zero, the certificate should be considered to be revoked from that time and onwards.
1143 // Using the dbt to get the trusted TSA certificates.
1144 //
1145 DbtDataSize = 0;
1146 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE2, &gEfiImageSecurityDatabaseGuid, NULL, &DbtDataSize, NULL);
1147 if (Status != EFI_BUFFER_TOO_SMALL) {
1148 goto Done;
1149 }
1150 DbtData = (UINT8 *) AllocateZeroPool (DbtDataSize);
1151 if (DbtData == NULL) {
1152 goto Done;
1153 }
1154 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE2, &gEfiImageSecurityDatabaseGuid, NULL, &DbtDataSize, (VOID *) DbtData);
1155 if (EFI_ERROR (Status)) {
1156 goto Done;
1157 }
1158
1159 CertList = (EFI_SIGNATURE_LIST *) DbtData;
1160 while ((DbtDataSize > 0) && (DbtDataSize >= CertList->SignatureListSize)) {
1161 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
1162 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1163 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1164 for (Index = 0; Index < CertCount; Index++) {
1165 //
1166 // Iterate each Signature Data Node within this CertList for verify.
1167 //
1168 RootCert = Cert->SignatureData;
1169 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
1170 //
1171 // Get the signing time if the timestamp signature is valid.
1172 //
1173 if (ImageTimestampVerify (AuthData, AuthDataSize, RootCert, RootCertSize, &SigningTime)) {
1174 //
1175 // The signer signature is valid only when the signing time is earlier than revocation time.
1176 //
1177 if (IsValidSignatureByTimestamp (&SigningTime, RevocationTime)) {
1178 VerifyStatus = TRUE;
1179 goto Done;
1180 }
1181 }
1182 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
1183 }
1184 }
1185 DbtDataSize -= CertList->SignatureListSize;
1186 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1187 }
1188
1189 Done:
1190 if (DbtData != NULL) {
1191 FreePool (DbtData);
1192 }
1193
1194 return VerifyStatus;
1195 }
1196
1197 /**
1198 Check whether the image signature is forbidden by the forbidden database (dbx).
1199 The image is forbidden to load if any certificates for signing are revoked before signing time.
1200
1201 @param[in] AuthData Pointer to the Authenticode signature retrieved from the signed image.
1202 @param[in] AuthDataSize Size of the Authenticode signature in bytes.
1203
1204 @retval TRUE Image is forbidden by dbx.
1205 @retval FALSE Image is not forbidden by dbx.
1206
1207 **/
1208 BOOLEAN
1209 IsForbiddenByDbx (
1210 IN UINT8 *AuthData,
1211 IN UINTN AuthDataSize
1212 )
1213 {
1214 EFI_STATUS Status;
1215 BOOLEAN IsForbidden;
1216 UINT8 *Data;
1217 UINTN DataSize;
1218 EFI_SIGNATURE_LIST *CertList;
1219 UINTN CertListSize;
1220 EFI_SIGNATURE_DATA *CertData;
1221 UINT8 *RootCert;
1222 UINTN RootCertSize;
1223 UINTN CertCount;
1224 UINTN Index;
1225 UINT8 *CertBuffer;
1226 UINTN BufferLength;
1227 UINT8 *TrustedCert;
1228 UINTN TrustedCertLength;
1229 UINT8 CertNumber;
1230 UINT8 *CertPtr;
1231 UINT8 *Cert;
1232 UINTN CertSize;
1233 EFI_TIME RevocationTime;
1234 //
1235 // Variable Initialization
1236 //
1237 IsForbidden = FALSE;
1238 Data = NULL;
1239 CertList = NULL;
1240 CertData = NULL;
1241 RootCert = NULL;
1242 RootCertSize = 0;
1243 Cert = NULL;
1244 CertBuffer = NULL;
1245 BufferLength = 0;
1246 TrustedCert = NULL;
1247 TrustedCertLength = 0;
1248
1249 //
1250 // The image will not be forbidden if dbx can't be got.
1251 //
1252 DataSize = 0;
1253 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
1254 if (Status != EFI_BUFFER_TOO_SMALL) {
1255 return IsForbidden;
1256 }
1257 Data = (UINT8 *) AllocateZeroPool (DataSize);
1258 if (Data == NULL) {
1259 return IsForbidden;
1260 }
1261
1262 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data);
1263 if (EFI_ERROR (Status)) {
1264 return IsForbidden;
1265 }
1266
1267 //
1268 // Verify image signature with RAW X509 certificates in DBX database.
1269 // If passed, the image will be forbidden.
1270 //
1271 CertList = (EFI_SIGNATURE_LIST *) Data;
1272 CertListSize = DataSize;
1273 while ((CertListSize > 0) && (CertListSize >= CertList->SignatureListSize)) {
1274 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
1275 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1276 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1277
1278 for (Index = 0; Index < CertCount; Index++) {
1279 //
1280 // Iterate each Signature Data Node within this CertList for verify.
1281 //
1282 RootCert = CertData->SignatureData;
1283 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
1284
1285 //
1286 // Call AuthenticodeVerify library to Verify Authenticode struct.
1287 //
1288 IsForbidden = AuthenticodeVerify (
1289 AuthData,
1290 AuthDataSize,
1291 RootCert,
1292 RootCertSize,
1293 mImageDigest,
1294 mImageDigestSize
1295 );
1296 if (IsForbidden) {
1297 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature is forbidden by DBX.\n"));
1298 goto Done;
1299 }
1300
1301 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize);
1302 }
1303 }
1304
1305 CertListSize -= CertList->SignatureListSize;
1306 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1307 }
1308
1309 //
1310 // Check X.509 Certificate Hash & Possible Timestamp.
1311 //
1312
1313 //
1314 // Retrieve the certificate stack from AuthData
1315 // The output CertStack format will be:
1316 // UINT8 CertNumber;
1317 // UINT32 Cert1Length;
1318 // UINT8 Cert1[];
1319 // UINT32 Cert2Length;
1320 // UINT8 Cert2[];
1321 // ...
1322 // UINT32 CertnLength;
1323 // UINT8 Certn[];
1324 //
1325 Pkcs7GetSigners (AuthData, AuthDataSize, &CertBuffer, &BufferLength, &TrustedCert, &TrustedCertLength);
1326 if ((BufferLength == 0) || (CertBuffer == NULL)) {
1327 IsForbidden = TRUE;
1328 goto Done;
1329 }
1330
1331 //
1332 // Check if any hash of certificates embedded in AuthData is in the forbidden database.
1333 //
1334 CertNumber = (UINT8) (*CertBuffer);
1335 CertPtr = CertBuffer + 1;
1336 for (Index = 0; Index < CertNumber; Index++) {
1337 CertSize = (UINTN) ReadUnaligned32 ((UINT32 *)CertPtr);
1338 Cert = (UINT8 *)CertPtr + sizeof (UINT32);
1339 //
1340 // Advance CertPtr to the next cert in image signer's cert list
1341 //
1342 CertPtr = CertPtr + sizeof (UINT32) + CertSize;
1343
1344 if (IsCertHashFoundInDatabase (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data, DataSize, &RevocationTime)) {
1345 //
1346 // Check the timestamp signature and signing time to determine if the image can be trusted.
1347 //
1348 IsForbidden = TRUE;
1349 if (PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime)) {
1350 IsForbidden = FALSE;
1351 //
1352 // Pass DBT check. Continue to check other certs in image signer's cert list against DBX, DBT
1353 //
1354 continue;
1355 }
1356 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature failed the timestamp check.\n"));
1357 goto Done;
1358 }
1359
1360 }
1361
1362 Done:
1363 if (Data != NULL) {
1364 FreePool (Data);
1365 }
1366
1367 Pkcs7FreeSigners (CertBuffer);
1368 Pkcs7FreeSigners (TrustedCert);
1369
1370 return IsForbidden;
1371 }
1372
1373
1374 /**
1375 Check whether the image signature can be verified by the trusted certificates in DB database.
1376
1377 @param[in] AuthData Pointer to the Authenticode signature retrieved from signed image.
1378 @param[in] AuthDataSize Size of the Authenticode signature in bytes.
1379
1380 @retval TRUE Image passed verification using certificate in db.
1381 @retval FALSE Image didn't pass verification using certificate in db.
1382
1383 **/
1384 BOOLEAN
1385 IsAllowedByDb (
1386 IN UINT8 *AuthData,
1387 IN UINTN AuthDataSize
1388 )
1389 {
1390 EFI_STATUS Status;
1391 BOOLEAN VerifyStatus;
1392 EFI_SIGNATURE_LIST *CertList;
1393 EFI_SIGNATURE_DATA *CertData;
1394 UINTN DataSize;
1395 UINT8 *Data;
1396 UINT8 *RootCert;
1397 UINTN RootCertSize;
1398 UINTN Index;
1399 UINTN CertCount;
1400 UINTN DbxDataSize;
1401 UINT8 *DbxData;
1402 EFI_TIME RevocationTime;
1403
1404 Data = NULL;
1405 CertList = NULL;
1406 CertData = NULL;
1407 RootCert = NULL;
1408 DbxData = NULL;
1409 RootCertSize = 0;
1410 VerifyStatus = FALSE;
1411
1412 DataSize = 0;
1413 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
1414 if (Status == EFI_BUFFER_TOO_SMALL) {
1415 Data = (UINT8 *) AllocateZeroPool (DataSize);
1416 if (Data == NULL) {
1417 return VerifyStatus;
1418 }
1419
1420 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data);
1421 if (EFI_ERROR (Status)) {
1422 goto Done;
1423 }
1424
1425 //
1426 // Find X509 certificate in Signature List to verify the signature in pkcs7 signed data.
1427 //
1428 CertList = (EFI_SIGNATURE_LIST *) Data;
1429 while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
1430 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
1431 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
1432 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
1433
1434 for (Index = 0; Index < CertCount; Index++) {
1435 //
1436 // Iterate each Signature Data Node within this CertList for verify.
1437 //
1438 RootCert = CertData->SignatureData;
1439 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
1440
1441 //
1442 // Call AuthenticodeVerify library to Verify Authenticode struct.
1443 //
1444 VerifyStatus = AuthenticodeVerify (
1445 AuthData,
1446 AuthDataSize,
1447 RootCert,
1448 RootCertSize,
1449 mImageDigest,
1450 mImageDigestSize
1451 );
1452 if (VerifyStatus) {
1453 //
1454 // Here We still need to check if this RootCert's Hash is revoked
1455 //
1456 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, NULL);
1457 if (Status == EFI_BUFFER_TOO_SMALL) {
1458 goto Done;
1459 }
1460 DbxData = (UINT8 *) AllocateZeroPool (DbxDataSize);
1461 if (DbxData == NULL) {
1462 goto Done;
1463 }
1464
1465 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, (VOID *) DbxData);
1466 if (EFI_ERROR (Status)) {
1467 goto Done;
1468 }
1469
1470 if (IsCertHashFoundInDatabase (RootCert, RootCertSize, (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime)) {
1471 //
1472 // Check the timestamp signature and signing time to determine if the RootCert can be trusted.
1473 //
1474 VerifyStatus = PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime);
1475 if (!VerifyStatus) {
1476 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed and signature is accepted by DB, but its root cert failed the timestamp check.\n"));
1477 }
1478 }
1479
1480 goto Done;
1481 }
1482
1483 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize);
1484 }
1485 }
1486
1487 DataSize -= CertList->SignatureListSize;
1488 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
1489 }
1490 }
1491
1492 Done:
1493
1494 if (VerifyStatus) {
1495 SecureBootHook (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, CertList->SignatureSize, CertData);
1496 }
1497
1498 if (Data != NULL) {
1499 FreePool (Data);
1500 }
1501 if (DbxData != NULL) {
1502 FreePool (DbxData);
1503 }
1504
1505 return VerifyStatus;
1506 }
1507
1508 /**
1509 Provide verification service for signed images, which include both signature validation
1510 and platform policy control. For signature types, both UEFI WIN_CERTIFICATE_UEFI_GUID and
1511 MSFT Authenticode type signatures are supported.
1512
1513 In this implementation, only verify external executables when in USER MODE.
1514 Executables from FV is bypass, so pass in AuthenticationStatus is ignored.
1515
1516 The image verification policy is:
1517 If the image is signed,
1518 At least one valid signature or at least one hash value of the image must match a record
1519 in the security database "db", and no valid signature nor any hash value of the image may
1520 be reflected in the security database "dbx".
1521 Otherwise, the image is not signed,
1522 The SHA256 hash value of the image must match a record in the security database "db", and
1523 not be reflected in the security data base "dbx".
1524
1525 Caution: This function may receive untrusted input.
1526 PE/COFF image is external input, so this function will validate its data structure
1527 within this image buffer before use.
1528
1529 @param[in] AuthenticationStatus
1530 This is the authentication status returned from the security
1531 measurement services for the input file.
1532 @param[in] File This is a pointer to the device path of the file that is
1533 being dispatched. This will optionally be used for logging.
1534 @param[in] FileBuffer File buffer matches the input file device path.
1535 @param[in] FileSize Size of File buffer matches the input file device path.
1536 @param[in] BootPolicy A boot policy that was used to call LoadImage() UEFI service.
1537
1538 @retval EFI_SUCCESS The file specified by DevicePath and non-NULL
1539 FileBuffer did authenticate, and the platform policy dictates
1540 that the DXE Foundation may use the file.
1541 @retval EFI_SUCCESS The device path specified by NULL device path DevicePath
1542 and non-NULL FileBuffer did authenticate, and the platform
1543 policy dictates that the DXE Foundation may execute the image in
1544 FileBuffer.
1545 @retval EFI_SECURITY_VIOLATION The file specified by File did not authenticate, and
1546 the platform policy dictates that File should be placed
1547 in the untrusted state. The image has been added to the file
1548 execution table.
1549 @retval EFI_ACCESS_DENIED The file specified by File and FileBuffer did not
1550 authenticate, and the platform policy dictates that the DXE
1551 Foundation may not use File. The image has
1552 been added to the file execution table.
1553
1554 **/
1555 EFI_STATUS
1556 EFIAPI
1557 DxeImageVerificationHandler (
1558 IN UINT32 AuthenticationStatus,
1559 IN CONST EFI_DEVICE_PATH_PROTOCOL *File,
1560 IN VOID *FileBuffer,
1561 IN UINTN FileSize,
1562 IN BOOLEAN BootPolicy
1563 )
1564 {
1565 EFI_IMAGE_DOS_HEADER *DosHdr;
1566 BOOLEAN IsVerified;
1567 EFI_SIGNATURE_LIST *SignatureList;
1568 UINTN SignatureListSize;
1569 EFI_SIGNATURE_DATA *Signature;
1570 EFI_IMAGE_EXECUTION_ACTION Action;
1571 WIN_CERTIFICATE *WinCertificate;
1572 UINT32 Policy;
1573 UINT8 *SecureBoot;
1574 PE_COFF_LOADER_IMAGE_CONTEXT ImageContext;
1575 UINT32 NumberOfRvaAndSizes;
1576 WIN_CERTIFICATE_EFI_PKCS *PkcsCertData;
1577 WIN_CERTIFICATE_UEFI_GUID *WinCertUefiGuid;
1578 UINT8 *AuthData;
1579 UINTN AuthDataSize;
1580 EFI_IMAGE_DATA_DIRECTORY *SecDataDir;
1581 UINT32 OffSet;
1582 CHAR16 *NameStr;
1583 RETURN_STATUS PeCoffStatus;
1584 EFI_STATUS HashStatus;
1585
1586 SignatureList = NULL;
1587 SignatureListSize = 0;
1588 WinCertificate = NULL;
1589 SecDataDir = NULL;
1590 PkcsCertData = NULL;
1591 Action = EFI_IMAGE_EXECUTION_AUTH_UNTESTED;
1592 IsVerified = FALSE;
1593
1594
1595 //
1596 // Check the image type and get policy setting.
1597 //
1598 switch (GetImageType (File)) {
1599
1600 case IMAGE_FROM_FV:
1601 Policy = ALWAYS_EXECUTE;
1602 break;
1603
1604 case IMAGE_FROM_OPTION_ROM:
1605 Policy = PcdGet32 (PcdOptionRomImageVerificationPolicy);
1606 break;
1607
1608 case IMAGE_FROM_REMOVABLE_MEDIA:
1609 Policy = PcdGet32 (PcdRemovableMediaImageVerificationPolicy);
1610 break;
1611
1612 case IMAGE_FROM_FIXED_MEDIA:
1613 Policy = PcdGet32 (PcdFixedMediaImageVerificationPolicy);
1614 break;
1615
1616 default:
1617 Policy = DENY_EXECUTE_ON_SECURITY_VIOLATION;
1618 break;
1619 }
1620 //
1621 // If policy is always/never execute, return directly.
1622 //
1623 if (Policy == ALWAYS_EXECUTE) {
1624 return EFI_SUCCESS;
1625 }
1626 if (Policy == NEVER_EXECUTE) {
1627 return EFI_ACCESS_DENIED;
1628 }
1629
1630 //
1631 // The policy QUERY_USER_ON_SECURITY_VIOLATION and ALLOW_EXECUTE_ON_SECURITY_VIOLATION
1632 // violates the UEFI spec and has been removed.
1633 //
1634 ASSERT (Policy != QUERY_USER_ON_SECURITY_VIOLATION && Policy != ALLOW_EXECUTE_ON_SECURITY_VIOLATION);
1635 if (Policy == QUERY_USER_ON_SECURITY_VIOLATION || Policy == ALLOW_EXECUTE_ON_SECURITY_VIOLATION) {
1636 CpuDeadLoop ();
1637 }
1638
1639 GetEfiGlobalVariable2 (EFI_SECURE_BOOT_MODE_NAME, (VOID**)&SecureBoot, NULL);
1640 //
1641 // Skip verification if SecureBoot variable doesn't exist.
1642 //
1643 if (SecureBoot == NULL) {
1644 return EFI_SUCCESS;
1645 }
1646
1647 //
1648 // Skip verification if SecureBoot is disabled but not AuditMode
1649 //
1650 if (*SecureBoot == SECURE_BOOT_MODE_DISABLE) {
1651 FreePool (SecureBoot);
1652 return EFI_SUCCESS;
1653 }
1654 FreePool (SecureBoot);
1655
1656 //
1657 // Read the Dos header.
1658 //
1659 if (FileBuffer == NULL) {
1660 return EFI_ACCESS_DENIED;
1661 }
1662
1663 mImageBase = (UINT8 *) FileBuffer;
1664 mImageSize = FileSize;
1665
1666 ZeroMem (&ImageContext, sizeof (ImageContext));
1667 ImageContext.Handle = (VOID *) FileBuffer;
1668 ImageContext.ImageRead = (PE_COFF_LOADER_READ_FILE) DxeImageVerificationLibImageRead;
1669
1670 //
1671 // Get information about the image being loaded
1672 //
1673 PeCoffStatus = PeCoffLoaderGetImageInfo (&ImageContext);
1674 if (RETURN_ERROR (PeCoffStatus)) {
1675 //
1676 // The information can't be got from the invalid PeImage
1677 //
1678 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: PeImage invalid. Cannot retrieve image information.\n"));
1679 goto Failed;
1680 }
1681
1682 DosHdr = (EFI_IMAGE_DOS_HEADER *) mImageBase;
1683 if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) {
1684 //
1685 // DOS image header is present,
1686 // so read the PE header after the DOS image header.
1687 //
1688 mPeCoffHeaderOffset = DosHdr->e_lfanew;
1689 } else {
1690 mPeCoffHeaderOffset = 0;
1691 }
1692 //
1693 // Check PE/COFF image.
1694 //
1695 mNtHeader.Pe32 = (EFI_IMAGE_NT_HEADERS32 *) (mImageBase + mPeCoffHeaderOffset);
1696 if (mNtHeader.Pe32->Signature != EFI_IMAGE_NT_SIGNATURE) {
1697 //
1698 // It is not a valid Pe/Coff file.
1699 //
1700 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Not a valid PE/COFF image.\n"));
1701 goto Failed;
1702 }
1703
1704 if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
1705 //
1706 // Use PE32 offset.
1707 //
1708 NumberOfRvaAndSizes = mNtHeader.Pe32->OptionalHeader.NumberOfRvaAndSizes;
1709 if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
1710 SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
1711 }
1712 } else {
1713 //
1714 // Use PE32+ offset.
1715 //
1716 NumberOfRvaAndSizes = mNtHeader.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes;
1717 if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
1718 SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
1719 }
1720 }
1721
1722 //
1723 // Start Image Validation.
1724 //
1725 if (SecDataDir == NULL || SecDataDir->Size == 0) {
1726 //
1727 // This image is not signed. The SHA256 hash value of the image must match a record in the security database "db",
1728 // and not be reflected in the security data base "dbx".
1729 //
1730 if (!HashPeImage (HASHALG_SHA256)) {
1731 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Failed to hash this image using %s.\n", mHashTypeStr));
1732 goto Failed;
1733 }
1734
1735 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) {
1736 //
1737 // Image Hash is in forbidden database (DBX).
1738 //
1739 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is not signed and %s hash of image is forbidden by DBX.\n", mHashTypeStr));
1740 goto Failed;
1741 }
1742
1743 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) {
1744 //
1745 // Image Hash is in allowed database (DB).
1746 //
1747 return EFI_SUCCESS;
1748 }
1749
1750 //
1751 // Image Hash is not found in both forbidden and allowed database.
1752 //
1753 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is not signed and %s hash of image is not found in DB/DBX.\n", mHashTypeStr));
1754 goto Failed;
1755 }
1756
1757 //
1758 // Verify the signature of the image, multiple signatures are allowed as per PE/COFF Section 4.7
1759 // "Attribute Certificate Table".
1760 // The first certificate starts at offset (SecDataDir->VirtualAddress) from the start of the file.
1761 //
1762 for (OffSet = SecDataDir->VirtualAddress;
1763 OffSet < (SecDataDir->VirtualAddress + SecDataDir->Size);
1764 OffSet += (WinCertificate->dwLength + ALIGN_SIZE (WinCertificate->dwLength))) {
1765 WinCertificate = (WIN_CERTIFICATE *) (mImageBase + OffSet);
1766 if ((SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) <= sizeof (WIN_CERTIFICATE) ||
1767 (SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) < WinCertificate->dwLength) {
1768 break;
1769 }
1770
1771 //
1772 // Verify the image's Authenticode signature, only DER-encoded PKCS#7 signed data is supported.
1773 //
1774 if (WinCertificate->wCertificateType == WIN_CERT_TYPE_PKCS_SIGNED_DATA) {
1775 //
1776 // The certificate is formatted as WIN_CERTIFICATE_EFI_PKCS which is described in the
1777 // Authenticode specification.
1778 //
1779 PkcsCertData = (WIN_CERTIFICATE_EFI_PKCS *) WinCertificate;
1780 if (PkcsCertData->Hdr.dwLength <= sizeof (PkcsCertData->Hdr)) {
1781 break;
1782 }
1783 AuthData = PkcsCertData->CertData;
1784 AuthDataSize = PkcsCertData->Hdr.dwLength - sizeof(PkcsCertData->Hdr);
1785 } else if (WinCertificate->wCertificateType == WIN_CERT_TYPE_EFI_GUID) {
1786 //
1787 // The certificate is formatted as WIN_CERTIFICATE_UEFI_GUID which is described in UEFI Spec.
1788 //
1789 WinCertUefiGuid = (WIN_CERTIFICATE_UEFI_GUID *) WinCertificate;
1790 if (WinCertUefiGuid->Hdr.dwLength <= OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData)) {
1791 break;
1792 }
1793 if (!CompareGuid (&WinCertUefiGuid->CertType, &gEfiCertPkcs7Guid)) {
1794 continue;
1795 }
1796 AuthData = WinCertUefiGuid->CertData;
1797 AuthDataSize = WinCertUefiGuid->Hdr.dwLength - OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData);
1798 } else {
1799 if (WinCertificate->dwLength < sizeof (WIN_CERTIFICATE)) {
1800 break;
1801 }
1802 continue;
1803 }
1804
1805 HashStatus = HashPeImageByType (AuthData, AuthDataSize);
1806 if (EFI_ERROR (HashStatus)) {
1807 continue;
1808 }
1809
1810 //
1811 // Check the digital signature against the revoked certificate in forbidden database (dbx).
1812 //
1813 if (IsForbiddenByDbx (AuthData, AuthDataSize)) {
1814 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED;
1815 IsVerified = FALSE;
1816 break;
1817 }
1818
1819 //
1820 // Check the digital signature against the valid certificate in allowed database (db).
1821 //
1822 if (!IsVerified) {
1823 if (IsAllowedByDb (AuthData, AuthDataSize)) {
1824 IsVerified = TRUE;
1825 }
1826 }
1827
1828 //
1829 // Check the image's hash value.
1830 //
1831 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) {
1832 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND;
1833 DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but %s hash of image is found in DBX.\n", mHashTypeStr));
1834 IsVerified = FALSE;
1835 break;
1836 }
1837 if (!IsVerified) {
1838 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) {
1839 IsVerified = TRUE;
1840 } else {
1841 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));
1842 }
1843 }
1844 }
1845
1846 if (OffSet != (SecDataDir->VirtualAddress + SecDataDir->Size)) {
1847 //
1848 // The Size in Certificate Table or the attribute certificate table is corrupted.
1849 //
1850 IsVerified = FALSE;
1851 }
1852
1853 if (IsVerified) {
1854 return EFI_SUCCESS;
1855 }
1856 if (Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED || Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND) {
1857 //
1858 // Get image hash value as signature of executable.
1859 //
1860 SignatureListSize = sizeof (EFI_SIGNATURE_LIST) + sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize;
1861 SignatureList = (EFI_SIGNATURE_LIST *) AllocateZeroPool (SignatureListSize);
1862 if (SignatureList == NULL) {
1863 SignatureListSize = 0;
1864 goto Failed;
1865 }
1866 SignatureList->SignatureHeaderSize = 0;
1867 SignatureList->SignatureListSize = (UINT32) SignatureListSize;
1868 SignatureList->SignatureSize = (UINT32) (sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize);
1869 CopyMem (&SignatureList->SignatureType, &mCertType, sizeof (EFI_GUID));
1870 Signature = (EFI_SIGNATURE_DATA *) ((UINT8 *) SignatureList + sizeof (EFI_SIGNATURE_LIST));
1871 CopyMem (Signature->SignatureData, mImageDigest, mImageDigestSize);
1872 }
1873
1874 Failed:
1875 //
1876 // Policy decides to defer or reject the image; add its information in image
1877 // executable information table in either case.
1878 //
1879 NameStr = ConvertDevicePathToText (File, FALSE, TRUE);
1880 AddImageExeInfo (Action, NameStr, File, SignatureList, SignatureListSize);
1881 if (NameStr != NULL) {
1882 DEBUG ((DEBUG_INFO, "The image doesn't pass verification: %s\n", NameStr));
1883 FreePool(NameStr);
1884 }
1885
1886 if (SignatureList != NULL) {
1887 FreePool (SignatureList);
1888 }
1889
1890 if (Policy == DEFER_EXECUTE_ON_SECURITY_VIOLATION) {
1891 return EFI_SECURITY_VIOLATION;
1892 }
1893 return EFI_ACCESS_DENIED;
1894 }
1895
1896 /**
1897 On Ready To Boot Services Event notification handler.
1898
1899 Add the image execution information table if it is not in system configuration table.
1900
1901 @param[in] Event Event whose notification function is being invoked
1902 @param[in] Context Pointer to the notification function's context
1903
1904 **/
1905 VOID
1906 EFIAPI
1907 OnReadyToBoot (
1908 IN EFI_EVENT Event,
1909 IN VOID *Context
1910 )
1911 {
1912 EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable;
1913 UINTN ImageExeInfoTableSize;
1914
1915 EfiGetSystemConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID **) &ImageExeInfoTable);
1916 if (ImageExeInfoTable != NULL) {
1917 return;
1918 }
1919
1920 ImageExeInfoTableSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE);
1921 ImageExeInfoTable = (EFI_IMAGE_EXECUTION_INFO_TABLE *) AllocateRuntimePool (ImageExeInfoTableSize);
1922 if (ImageExeInfoTable == NULL) {
1923 return ;
1924 }
1925
1926 ImageExeInfoTable->NumberOfImages = 0;
1927 gBS->InstallConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID *) ImageExeInfoTable);
1928
1929 }
1930
1931 /**
1932 Register security measurement handler.
1933
1934 @param ImageHandle ImageHandle of the loaded driver.
1935 @param SystemTable Pointer to the EFI System Table.
1936
1937 @retval EFI_SUCCESS The handlers were registered successfully.
1938 **/
1939 EFI_STATUS
1940 EFIAPI
1941 DxeImageVerificationLibConstructor (
1942 IN EFI_HANDLE ImageHandle,
1943 IN EFI_SYSTEM_TABLE *SystemTable
1944 )
1945 {
1946 EFI_EVENT Event;
1947
1948 //
1949 // Register the event to publish the image execution table.
1950 //
1951 EfiCreateEventReadyToBootEx (
1952 TPL_CALLBACK,
1953 OnReadyToBoot,
1954 NULL,
1955 &Event
1956 );
1957
1958 return RegisterSecurity2Handler (
1959 DxeImageVerificationHandler,
1960 EFI_AUTH_OPERATION_VERIFY_IMAGE | EFI_AUTH_OPERATION_IMAGE_REQUIRED
1961 );
1962 }
EFI Development Kit II mirror for PVE