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 15Copyright (c) 2009 - 2015, Intel Corporation. All rights reserved.<BR> 16This program and the accompanying materials 17are licensed and made available under the terms and conditions of the BSD License 18which accompanies this distribution. The full text of the license may be found at 19http://opensource.org/licenses/bsd-license.php 20 21THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 22WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 23 24**/ 25 26#include "DxeImageVerificationLib.h" 27 28// 29// Caution: This is used by a function which may receive untrusted input. 30// These global variables hold PE/COFF image data, and they should be validated before use. 31// 32EFI_IMAGE_OPTIONAL_HEADER_PTR_UNION mNtHeader; 33UINT32 mPeCoffHeaderOffset; 34EFI_GUID mCertType; 35 36// 37// Information on current PE/COFF image 38// 39UINTN mImageSize; 40UINT8 *mImageBase = NULL; 41UINT8 mImageDigest[MAX_DIGEST_SIZE]; 42UINTN mImageDigestSize; 43 44// 45// Notify string for authorization UI. 46// 47CHAR16 mNotifyString1[MAX_NOTIFY_STRING_LEN] = L"Image verification pass but not found in authorized database!"; 48CHAR16 mNotifyString2[MAX_NOTIFY_STRING_LEN] = L"Launch this image anyway? (Yes/Defer/No)"; 49// 50// Public Exponent of RSA Key. 51// 52CONST UINT8 mRsaE[] = { 0x01, 0x00, 0x01 }; 53 54 55// 56// OID ASN.1 Value for Hash Algorithms 57// 58UINT8 mHashOidValue[] = { 59 0x2B, 0x0E, 0x03, 0x02, 0x1A, // OBJ_sha1 60 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04, // OBJ_sha224 61 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, // OBJ_sha256 62 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, // OBJ_sha384 63 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, // OBJ_sha512 64 }; 65 66HASH_TABLE mHash[] = { 67 { L"SHA1", 20, &mHashOidValue[0], 5, Sha1GetContextSize, Sha1Init, Sha1Update, Sha1Final }, 68 { L"SHA224", 28, &mHashOidValue[5], 9, NULL, NULL, NULL, NULL }, 69 { L"SHA256", 32, &mHashOidValue[14], 9, Sha256GetContextSize, Sha256Init, Sha256Update, Sha256Final}, 70 { L"SHA384", 48, &mHashOidValue[23], 9, Sha384GetContextSize, Sha384Init, Sha384Update, Sha384Final}, 71 { L"SHA512", 64, &mHashOidValue[32], 9, Sha512GetContextSize, Sha512Init, Sha512Update, Sha512Final} 72}; 73 74/** 75 SecureBoot Hook for processing image verification. 76 77 @param[in] VariableName Name of Variable to be found. 78 @param[in] VendorGuid Variable vendor GUID. 79 @param[in] DataSize Size of Data found. If size is less than the 80 data, this value contains the required size. 81 @param[in] Data Data pointer. 82 83**/ 84VOID 85EFIAPI 86SecureBootHook ( 87 IN CHAR16 *VariableName, 88 IN EFI_GUID *VendorGuid, 89 IN UINTN DataSize, 90 IN VOID *Data 91 ); 92 93/** 94 Reads contents of a PE/COFF image in memory buffer. 95 96 Caution: This function may receive untrusted input. 97 PE/COFF image is external input, so this function will make sure the PE/COFF image content 98 read is within the image buffer. 99 100 @param FileHandle Pointer to the file handle to read the PE/COFF image. 101 @param FileOffset Offset into the PE/COFF image to begin the read operation. 102 @param ReadSize On input, the size in bytes of the requested read operation. 103 On output, the number of bytes actually read. 104 @param Buffer Output buffer that contains the data read from the PE/COFF image. 105 106 @retval EFI_SUCCESS The specified portion of the PE/COFF image was read and the size 107**/ 108EFI_STATUS 109EFIAPI 110DxeImageVerificationLibImageRead ( 111 IN VOID *FileHandle, 112 IN UINTN FileOffset, 113 IN OUT UINTN *ReadSize, 114 OUT VOID *Buffer 115 ) 116{ 117 UINTN EndPosition; 118 119 if (FileHandle == NULL || ReadSize == NULL || Buffer == NULL) { 120 return EFI_INVALID_PARAMETER; 121 } 122 123 if (MAX_ADDRESS - FileOffset < *ReadSize) { 124 return EFI_INVALID_PARAMETER; 125 } 126 127 EndPosition = FileOffset + *ReadSize; 128 if (EndPosition > mImageSize) { 129 *ReadSize = (UINT32)(mImageSize - FileOffset); 130 } 131 132 if (FileOffset >= mImageSize) { 133 *ReadSize = 0; 134 } 135 136 CopyMem (Buffer, (UINT8 *)((UINTN) FileHandle + FileOffset), *ReadSize); 137 138 return EFI_SUCCESS; 139} 140 141 142/** 143 Get the image type. 144 145 @param[in] File This is a pointer to the device path of the file that is 146 being dispatched. 147 148 @return UINT32 Image Type 149 150**/ 151UINT32 152GetImageType ( 153 IN CONST EFI_DEVICE_PATH_PROTOCOL *File 154 ) 155{ 156 EFI_STATUS Status; 157 EFI_HANDLE DeviceHandle; 158 EFI_DEVICE_PATH_PROTOCOL *TempDevicePath; 159 EFI_BLOCK_IO_PROTOCOL *BlockIo; 160 161 if (File == NULL) { 162 return IMAGE_UNKNOWN; 163 } 164 165 // 166 // First check to see if File is from a Firmware Volume 167 // 168 DeviceHandle = NULL; 169 TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *) File; 170 Status = gBS->LocateDevicePath ( 171 &gEfiFirmwareVolume2ProtocolGuid, 172 &TempDevicePath, 173 &DeviceHandle 174 ); 175 if (!EFI_ERROR (Status)) { 176 Status = gBS->OpenProtocol ( 177 DeviceHandle, 178 &gEfiFirmwareVolume2ProtocolGuid, 179 NULL, 180 NULL, 181 NULL, 182 EFI_OPEN_PROTOCOL_TEST_PROTOCOL 183 ); 184 if (!EFI_ERROR (Status)) { 185 return IMAGE_FROM_FV; 186 } 187 } 188 189 // 190 // Next check to see if File is from a Block I/O device 191 // 192 DeviceHandle = NULL; 193 TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *) File; 194 Status = gBS->LocateDevicePath ( 195 &gEfiBlockIoProtocolGuid, 196 &TempDevicePath, 197 &DeviceHandle 198 ); 199 if (!EFI_ERROR (Status)) { 200 BlockIo = NULL; 201 Status = gBS->OpenProtocol ( 202 DeviceHandle, 203 &gEfiBlockIoProtocolGuid, 204 (VOID **) &BlockIo, 205 NULL, 206 NULL, 207 EFI_OPEN_PROTOCOL_GET_PROTOCOL 208 ); 209 if (!EFI_ERROR (Status) && BlockIo != NULL) { 210 if (BlockIo->Media != NULL) { 211 if (BlockIo->Media->RemovableMedia) { 212 // 213 // Block I/O is present and specifies the media is removable 214 // 215 return IMAGE_FROM_REMOVABLE_MEDIA; 216 } else { 217 // 218 // Block I/O is present and specifies the media is not removable 219 // 220 return IMAGE_FROM_FIXED_MEDIA; 221 } 222 } 223 } 224 } 225 226 // 227 // File is not in a Firmware Volume or on a Block I/O device, so check to see if 228 // the device path supports the Simple File System Protocol. 229 // 230 DeviceHandle = NULL; 231 TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *) File; 232 Status = gBS->LocateDevicePath ( 233 &gEfiSimpleFileSystemProtocolGuid, 234 &TempDevicePath, 235 &DeviceHandle 236 ); 237 if (!EFI_ERROR (Status)) { 238 // 239 // Simple File System is present without Block I/O, so assume media is fixed. 240 // 241 return IMAGE_FROM_FIXED_MEDIA; 242 } 243 244 // 245 // File is not from an FV, Block I/O or Simple File System, so the only options 246 // left are a PCI Option ROM and a Load File Protocol such as a PXE Boot from a NIC. 247 // 248 TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *) File; 249 while (!IsDevicePathEndType (TempDevicePath)) { 250 switch (DevicePathType (TempDevicePath)) { 251 252 case MEDIA_DEVICE_PATH: 253 if (DevicePathSubType (TempDevicePath) == MEDIA_RELATIVE_OFFSET_RANGE_DP) { 254 return IMAGE_FROM_OPTION_ROM; 255 } 256 break; 257 258 case MESSAGING_DEVICE_PATH: 259 if (DevicePathSubType(TempDevicePath) == MSG_MAC_ADDR_DP) { 260 return IMAGE_FROM_REMOVABLE_MEDIA; 261 } 262 break; 263 264 default: 265 break; 266 } 267 TempDevicePath = NextDevicePathNode (TempDevicePath); 268 } 269 return IMAGE_UNKNOWN; 270} 271 272/** 273 Calculate hash of Pe/Coff image based on the authenticode image hashing in 274 PE/COFF Specification 8.0 Appendix A 275 276 Caution: This function may receive untrusted input. 277 PE/COFF image is external input, so this function will validate its data structure 278 within this image buffer before use. 279 280 @param[in] HashAlg Hash algorithm type. 281 282 @retval TRUE Successfully hash image. 283 @retval FALSE Fail in hash image. 284 285**/ 286BOOLEAN 287HashPeImage ( 288 IN UINT32 HashAlg 289 ) 290{ 291 BOOLEAN Status; 292 UINT16 Magic; 293 EFI_IMAGE_SECTION_HEADER *Section; 294 VOID *HashCtx; 295 UINTN CtxSize; 296 UINT8 *HashBase; 297 UINTN HashSize; 298 UINTN SumOfBytesHashed; 299 EFI_IMAGE_SECTION_HEADER *SectionHeader; 300 UINTN Index; 301 UINTN Pos; 302 UINT32 CertSize; 303 UINT32 NumberOfRvaAndSizes; 304 305 HashCtx = NULL; 306 SectionHeader = NULL; 307 Status = FALSE; 308 309 if ((HashAlg >= HASHALG_MAX)) { 310 return FALSE; 311 } 312 313 // 314 // Initialize context of hash. 315 // 316 ZeroMem (mImageDigest, MAX_DIGEST_SIZE); 317 318 switch (HashAlg) { 319 case HASHALG_SHA1: 320 mImageDigestSize = SHA1_DIGEST_SIZE; 321 mCertType = gEfiCertSha1Guid; 322 break; 323 324 case HASHALG_SHA256: 325 mImageDigestSize = SHA256_DIGEST_SIZE; 326 mCertType = gEfiCertSha256Guid; 327 break; 328 329 case HASHALG_SHA384: 330 mImageDigestSize = SHA384_DIGEST_SIZE; 331 mCertType = gEfiCertSha384Guid; 332 break; 333 334 case HASHALG_SHA512: 335 mImageDigestSize = SHA512_DIGEST_SIZE; 336 mCertType = gEfiCertSha512Guid; 337 break; 338 339 default: 340 return FALSE; 341 } 342 343 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 if (mNtHeader.Pe32->FileHeader.Machine == IMAGE_FILE_MACHINE_IA64 && mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) { 364 // 365 // NOTE: Some versions of Linux ELILO for Itanium have an incorrect magic value 366 // in the PE/COFF Header. If the MachineType is Itanium(IA64) and the 367 // Magic value in the OptionalHeader is EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC 368 // then override the magic value to EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC 369 // 370 Magic = EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC; 371 } else { 372 // 373 // Get the magic value from the PE/COFF Optional Header 374 // 375 Magic = mNtHeader.Pe32->OptionalHeader.Magic; 376 } 377 378 // 379 // 3. Calculate the distance from the base of the image header to the image checksum address. 380 // 4. Hash the image header from its base to beginning of the image checksum. 381 // 382 HashBase = mImageBase; 383 if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) { 384 // 385 // Use PE32 offset. 386 // 387 HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32->OptionalHeader.CheckSum) - HashBase); 388 NumberOfRvaAndSizes = mNtHeader.Pe32->OptionalHeader.NumberOfRvaAndSizes; 389 } else if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC) { 390 // 391 // Use PE32+ offset. 392 // 393 HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32Plus->OptionalHeader.CheckSum) - HashBase); 394 NumberOfRvaAndSizes = mNtHeader.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes; 395 } else { 396 // 397 // Invalid header magic number. 398 // 399 Status = FALSE; 400 goto Done; 401 } 402 403 Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize); 404 if (!Status) { 405 goto Done; 406 } 407 408 // 409 // 5. Skip over the image checksum (it occupies a single ULONG). 410 // 411 if (NumberOfRvaAndSizes <= EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) { 412 // 413 // 6. Since there is no Cert Directory in optional header, hash everything 414 // from the end of the checksum to the end of image header. 415 // 416 if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) { 417 // 418 // Use PE32 offset. 419 // 420 HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.CheckSum + sizeof (UINT32); 421 HashSize = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders - (UINTN) (HashBase - mImageBase); 422 } else { 423 // 424 // Use PE32+ offset. 425 // 426 HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32); 427 HashSize = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders - (UINTN) (HashBase - mImageBase); 428 } 429 430 if (HashSize != 0) { 431 Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize); 432 if (!Status) { 433 goto Done; 434 } 435 } 436 } else { 437 // 438 // 7. Hash everything from the end of the checksum to the start of the Cert Directory. 439 // 440 if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) { 441 // 442 // Use PE32 offset. 443 // 444 HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.CheckSum + sizeof (UINT32); 445 HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase); 446 } else { 447 // 448 // Use PE32+ offset. 449 // 450 HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32); 451 HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase); 452 } 453 454 if (HashSize != 0) { 455 Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize); 456 if (!Status) { 457 goto Done; 458 } 459 } 460 461 // 462 // 8. Skip over the Cert Directory. (It is sizeof(IMAGE_DATA_DIRECTORY) bytes.) 463 // 9. Hash everything from the end of the Cert Directory to the end of image header. 464 // 465 if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) { 466 // 467 // Use PE32 offset 468 // 469 HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1]; 470 HashSize = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders - (UINTN) (HashBase - mImageBase); 471 } else { 472 // 473 // Use PE32+ offset. 474 // 475 HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1]; 476 HashSize = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders - (UINTN) (HashBase - mImageBase); 477 } 478 479 if (HashSize != 0) { 480 Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize); 481 if (!Status) { 482 goto Done; 483 } 484 } 485 } 486 487 // 488 // 10. Set the SUM_OF_BYTES_HASHED to the size of the header. 489 // 490 if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) { 491 // 492 // Use PE32 offset. 493 // 494 SumOfBytesHashed = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders; 495 } else { 496 // 497 // Use PE32+ offset 498 // 499 SumOfBytesHashed = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders; 500 } 501 502 503 Section = (EFI_IMAGE_SECTION_HEADER *) ( 504 mImageBase + 505 mPeCoffHeaderOffset + 506 sizeof (UINT32) + 507 sizeof (EFI_IMAGE_FILE_HEADER) + 508 mNtHeader.Pe32->FileHeader.SizeOfOptionalHeader 509 ); 510 511 // 512 // 11. Build a temporary table of pointers to all the IMAGE_SECTION_HEADER 513 // structures in the image. The 'NumberOfSections' field of the image 514 // header indicates how big the table should be. Do not include any 515 // IMAGE_SECTION_HEADERs in the table whose 'SizeOfRawData' field is zero. 516 // 517 SectionHeader = (EFI_IMAGE_SECTION_HEADER *) AllocateZeroPool (sizeof (EFI_IMAGE_SECTION_HEADER) * mNtHeader.Pe32->FileHeader.NumberOfSections); 518 if (SectionHeader == NULL) { 519 Status = FALSE; 520 goto Done; 521 } 522 // 523 // 12. Using the 'PointerToRawData' in the referenced section headers as 524 // a key, arrange the elements in the table in ascending order. In other 525 // words, sort the section headers according to the disk-file offset of 526 // the section. 527 // 528 for (Index = 0; Index < mNtHeader.Pe32->FileHeader.NumberOfSections; Index++) { 529 Pos = Index; 530 while ((Pos > 0) && (Section->PointerToRawData < SectionHeader[Pos - 1].PointerToRawData)) { 531 CopyMem (&SectionHeader[Pos], &SectionHeader[Pos - 1], sizeof (EFI_IMAGE_SECTION_HEADER)); 532 Pos--; 533 } 534 CopyMem (&SectionHeader[Pos], Section, sizeof (EFI_IMAGE_SECTION_HEADER)); 535 Section += 1; 536 } 537 538 // 539 // 13. Walk through the sorted table, bring the corresponding section 540 // into memory, and hash the entire section (using the 'SizeOfRawData' 541 // field in the section header to determine the amount of data to hash). 542 // 14. Add the section's 'SizeOfRawData' to SUM_OF_BYTES_HASHED . 543 // 15. Repeat steps 13 and 14 for all the sections in the sorted table. 544 // 545 for (Index = 0; Index < mNtHeader.Pe32->FileHeader.NumberOfSections; Index++) { 546 Section = &SectionHeader[Index]; 547 if (Section->SizeOfRawData == 0) { 548 continue; 549 } 550 HashBase = mImageBase + Section->PointerToRawData; 551 HashSize = (UINTN) Section->SizeOfRawData; 552 553 Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize); 554 if (!Status) { 555 goto Done; 556 } 557 558 SumOfBytesHashed += HashSize; 559 } 560 561 // 562 // 16. If the file size is greater than SUM_OF_BYTES_HASHED, there is extra 563 // data in the file that needs to be added to the hash. This data begins 564 // at file offset SUM_OF_BYTES_HASHED and its length is: 565 // FileSize - (CertDirectory->Size) 566 // 567 if (mImageSize > SumOfBytesHashed) { 568 HashBase = mImageBase + SumOfBytesHashed; 569 570 if (NumberOfRvaAndSizes <= EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) { 571 CertSize = 0; 572 } else { 573 if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) { 574 // 575 // Use PE32 offset. 576 // 577 CertSize = mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY].Size; 578 } else { 579 // 580 // Use PE32+ offset. 581 // 582 CertSize = mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY].Size; 583 } 584 } 585 586 if (mImageSize > CertSize + SumOfBytesHashed) { 587 HashSize = (UINTN) (mImageSize - CertSize - SumOfBytesHashed); 588 589 Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize); 590 if (!Status) { 591 goto Done; 592 } 593 } else if (mImageSize < CertSize + SumOfBytesHashed) { 594 Status = FALSE; 595 goto Done; 596 } 597 } 598 599 Status = mHash[HashAlg].HashFinal(HashCtx, mImageDigest); 600 601Done: 602 if (HashCtx != NULL) { 603 FreePool (HashCtx); 604 } 605 if (SectionHeader != NULL) { 606 FreePool (SectionHeader); 607 } 608 return Status; 609} 610 611/** 612 Recognize the Hash algorithm in PE/COFF Authenticode and calculate hash of 613 Pe/Coff image based on the authenticode image hashing in PE/COFF Specification 614 8.0 Appendix A 615 616 Caution: This function may receive untrusted input. 617 PE/COFF image is external input, so this function will validate its data structure 618 within this image buffer before use. 619 620 @param[in] AuthData Pointer to the Authenticode Signature retrieved from signed image. 621 @param[in] AuthDataSize Size of the Authenticode Signature in bytes. 622 623 @retval EFI_UNSUPPORTED Hash algorithm is not supported. 624 @retval EFI_SUCCESS Hash successfully. 625 626**/ 627EFI_STATUS 628HashPeImageByType ( 629 IN UINT8 *AuthData, 630 IN UINTN AuthDataSize 631 ) 632{ 633 UINT8 Index; 634 635 for (Index = 0; Index < HASHALG_MAX; Index++) { 636 // 637 // Check the Hash algorithm in PE/COFF Authenticode. 638 // According to PKCS#7 Definition: 639 // SignedData ::= SEQUENCE { 640 // version Version, 641 // digestAlgorithms DigestAlgorithmIdentifiers, 642 // contentInfo ContentInfo, 643 // .... } 644 // The DigestAlgorithmIdentifiers can be used to determine the hash algorithm in PE/COFF hashing 645 // This field has the fixed offset (+32) in final Authenticode ASN.1 data. 646 // Fixed offset (+32) is calculated based on two bytes of length encoding. 647 // 648 if ((*(AuthData + 1) & TWO_BYTE_ENCODE) != TWO_BYTE_ENCODE) { 649 // 650 // Only support two bytes of Long Form of Length Encoding. 651 // 652 continue; 653 } 654 655 if (AuthDataSize < 32 + mHash[Index].OidLength) { 656 return EFI_UNSUPPORTED; 657 } 658 659 if (CompareMem (AuthData + 32, mHash[Index].OidValue, mHash[Index].OidLength) == 0) { 660 break; 661 } 662 } 663 664 if (Index == HASHALG_MAX) { 665 return EFI_UNSUPPORTED; 666 } 667 668 // 669 // HASH PE Image based on Hash algorithm in PE/COFF Authenticode. 670 // 671 if (!HashPeImage(Index)) { 672 return EFI_UNSUPPORTED; 673 } 674 675 return EFI_SUCCESS; 676} 677 678 679/** 680 Returns the size of a given image execution info table in bytes. 681 682 This function returns the size, in bytes, of the image execution info table specified by 683 ImageExeInfoTable. If ImageExeInfoTable is NULL, then 0 is returned. 684 685 @param ImageExeInfoTable A pointer to a image execution info table structure. 686 687 @retval 0 If ImageExeInfoTable is NULL. 688 @retval Others The size of a image execution info table in bytes. 689 690**/ 691UINTN 692GetImageExeInfoTableSize ( 693 EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable 694 ) 695{ 696 UINTN Index; 697 EFI_IMAGE_EXECUTION_INFO *ImageExeInfoItem; 698 UINTN TotalSize; 699 700 if (ImageExeInfoTable == NULL) { 701 return 0; 702 } 703 704 ImageExeInfoItem = (EFI_IMAGE_EXECUTION_INFO *) ((UINT8 *) ImageExeInfoTable + sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE)); 705 TotalSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE); 706 for (Index = 0; Index < ImageExeInfoTable->NumberOfImages; Index++) { 707 TotalSize += ReadUnaligned32 ((UINT32 *) &ImageExeInfoItem->InfoSize); 708 ImageExeInfoItem = (EFI_IMAGE_EXECUTION_INFO *) ((UINT8 *) ImageExeInfoItem + ReadUnaligned32 ((UINT32 *) &ImageExeInfoItem->InfoSize)); 709 } 710 711 return TotalSize; 712} 713 714/** 715 Create signature list based on input signature data and certificate type GUID. Caller is reposible 716 to free new created SignatureList. 717 718 @param[in] SignatureData Signature data in SignatureList. 719 @param[in] SignatureDataSize Signature data size. 720 @param[in] CertType Certificate Type. 721 @param[out] SignatureList Created SignatureList. 722 @param[out] SignatureListSize Created SignatureListSize. 723 724 @return EFI_OUT_OF_RESOURCES The operation is failed due to lack of resources. 725 @retval EFI_SUCCESS Successfully create signature list. 726 727**/ 728EFI_STATUS 729CreateSignatureList( 730 IN UINT8 *SignatureData, 731 IN UINTN SignatureDataSize, 732 IN EFI_GUID *CertType, 733 OUT EFI_SIGNATURE_LIST **SignatureList, 734 OUT UINTN *SignatureListSize 735 ) 736{ 737 EFI_SIGNATURE_LIST *SignList; 738 UINTN SignListSize; 739 EFI_SIGNATURE_DATA *Signature; 740 741 SignList = NULL; 742 *SignatureList = NULL; 743 744 SignListSize = sizeof (EFI_SIGNATURE_LIST) + sizeof (EFI_SIGNATURE_DATA) - 1 + SignatureDataSize; 745 SignList = (EFI_SIGNATURE_LIST *) AllocateZeroPool (SignListSize); 746 if (SignList == NULL) { 747 return EFI_OUT_OF_RESOURCES; 748 } 749 750 SignList->SignatureHeaderSize = 0; 751 SignList->SignatureListSize = (UINT32) SignListSize; 752 SignList->SignatureSize = (UINT32) SignatureDataSize + sizeof (EFI_SIGNATURE_DATA) - 1; 753 CopyMem (&SignList->SignatureType, CertType, sizeof (EFI_GUID)); 754 755 DEBUG((EFI_D_INFO, "SignatureDataSize %x\n", SignatureDataSize)); 756 Signature = (EFI_SIGNATURE_DATA *) ((UINT8 *) SignList + sizeof (EFI_SIGNATURE_LIST)); 757 CopyMem (Signature->SignatureData, SignatureData, SignatureDataSize); 758 759 *SignatureList = SignList; 760 *SignatureListSize = SignListSize; 761 762 return EFI_SUCCESS; 763 764} 765 766/** 767 Create an Image Execution Information Table entry and add it to system configuration table. 768 769 @param[in] Action Describes the action taken by the firmware regarding this image. 770 @param[in] Name Input a null-terminated, user-friendly name. 771 @param[in] DevicePath Input device path pointer. 772 @param[in] Signature Input signature info in EFI_SIGNATURE_LIST data structure. 773 @param[in] SignatureSize Size of signature. 774 775**/ 776VOID 777AddImageExeInfo ( 778 IN EFI_IMAGE_EXECUTION_ACTION Action, 779 IN CHAR16 *Name OPTIONAL, 780 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, 781 IN EFI_SIGNATURE_LIST *Signature OPTIONAL, 782 IN UINTN SignatureSize 783 ) 784{ 785 EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable; 786 EFI_IMAGE_EXECUTION_INFO_TABLE *NewImageExeInfoTable; 787 EFI_IMAGE_EXECUTION_INFO *ImageExeInfoEntry; 788 UINTN ImageExeInfoTableSize; 789 UINTN NewImageExeInfoEntrySize; 790 UINTN NameStringLen; 791 UINTN DevicePathSize; 792 CHAR16 *NameStr; 793 794 ImageExeInfoTable = NULL; 795 NewImageExeInfoTable = NULL; 796 ImageExeInfoEntry = NULL; 797 NameStringLen = 0; 798 NameStr = NULL; 799 800 if (DevicePath == NULL) { 801 return ; 802 } 803 804 if (Name != NULL) { 805 NameStringLen = StrSize (Name); 806 } else { 807 NameStringLen = sizeof (CHAR16); 808 } 809 810 EfiGetSystemConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID **) &ImageExeInfoTable); 811 if (ImageExeInfoTable != NULL) { 812 // 813 // The table has been found! 814 // We must enlarge the table to accomodate the new exe info entry. 815 // 816 ImageExeInfoTableSize = GetImageExeInfoTableSize (ImageExeInfoTable); 817 } else { 818 // 819 // Not Found! 820 // We should create a new table to append to the configuration table. 821 // 822 ImageExeInfoTableSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE); 823 } 824 825 DevicePathSize = GetDevicePathSize (DevicePath); 826 827 // 828 // Signature size can be odd. Pad after signature to ensure next EXECUTION_INFO entry align 829 // 830 NewImageExeInfoEntrySize = sizeof (EFI_IMAGE_EXECUTION_INFO) + NameStringLen + DevicePathSize + SignatureSize; 831 832 NewImageExeInfoTable = (EFI_IMAGE_EXECUTION_INFO_TABLE *) AllocateRuntimePool (ImageExeInfoTableSize + NewImageExeInfoEntrySize); 833 if (NewImageExeInfoTable == NULL) { 834 return ; 835 } 836 837 if (ImageExeInfoTable != NULL) { 838 CopyMem (NewImageExeInfoTable, ImageExeInfoTable, ImageExeInfoTableSize); 839 } else { 840 NewImageExeInfoTable->NumberOfImages = 0; 841 } 842 NewImageExeInfoTable->NumberOfImages++; 843 ImageExeInfoEntry = (EFI_IMAGE_EXECUTION_INFO *) ((UINT8 *) NewImageExeInfoTable + ImageExeInfoTableSize); 844 // 845 // Update new item's information. 846 // 847 WriteUnaligned32 ((UINT32 *) ImageExeInfoEntry, Action); 848 WriteUnaligned32 ((UINT32 *) ((UINT8 *) ImageExeInfoEntry + sizeof (EFI_IMAGE_EXECUTION_ACTION)), (UINT32) NewImageExeInfoEntrySize); 849 850 NameStr = (CHAR16 *)(ImageExeInfoEntry + 1); 851 if (Name != NULL) { 852 CopyMem ((UINT8 *) NameStr, Name, NameStringLen); 853 } else { 854 ZeroMem ((UINT8 *) NameStr, sizeof (CHAR16)); 855 } 856 857 CopyMem ( 858 (UINT8 *) NameStr + NameStringLen, 859 DevicePath, 860 DevicePathSize 861 ); 862 if (Signature != NULL) { 863 CopyMem ( 864 (UINT8 *) NameStr + NameStringLen + DevicePathSize, 865 Signature, 866 SignatureSize 867 ); 868 } 869 // 870 // Update/replace the image execution table. 871 // 872 gBS->InstallConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID *) NewImageExeInfoTable); 873 874 // 875 // Free Old table data! 876 // 877 if (ImageExeInfoTable != NULL) { 878 FreePool (ImageExeInfoTable); 879 } 880} 881 882/** 883 Check whether the hash of an given X.509 certificate is in forbidden database (DBX). 884 885 @param[in] Certificate Pointer to X.509 Certificate that is searched for. 886 @param[in] CertSize Size of X.509 Certificate. 887 @param[in] SignatureList Pointer to the Signature List in forbidden database. 888 @param[in] SignatureListSize Size of Signature List. 889 @param[out] RevocationTime Return the time that the certificate was revoked. 890 891 @return TRUE The certificate hash is found in the forbidden database. 892 @return FALSE The certificate hash is not found in the forbidden database. 893 894**/ 895BOOLEAN 896IsCertHashFoundInDatabase ( 897 IN UINT8 *Certificate, 898 IN UINTN CertSize, 899 IN EFI_SIGNATURE_LIST *SignatureList, 900 IN UINTN SignatureListSize, 901 OUT EFI_TIME *RevocationTime 902 ) 903{ 904 BOOLEAN IsFound; 905 BOOLEAN Status; 906 EFI_SIGNATURE_LIST *DbxList; 907 UINTN DbxSize; 908 EFI_SIGNATURE_DATA *CertHash; 909 UINTN CertHashCount; 910 UINTN Index; 911 UINT32 HashAlg; 912 VOID *HashCtx; 913 UINT8 CertDigest[MAX_DIGEST_SIZE]; 914 UINT8 *DbxCertHash; 915 UINTN SiglistHeaderSize; 916 UINT8 *TBSCert; 917 UINTN TBSCertSize; 918 919 IsFound = FALSE; 920 DbxList = SignatureList; 921 DbxSize = SignatureListSize; 922 HashCtx = NULL; 923 HashAlg = HASHALG_MAX; 924 925 if ((RevocationTime == NULL) || (DbxList == NULL)) { 926 return FALSE; 927 } 928 929 // 930 // Retrieve the TBSCertificate from the X.509 Certificate. 931 // 932 if (!X509GetTBSCert (Certificate, CertSize, &TBSCert, &TBSCertSize)) { 933 return FALSE; 934 } 935 936 while ((DbxSize > 0) && (SignatureListSize >= DbxList->SignatureListSize)) { 937 // 938 // Determine Hash Algorithm of Certificate in the forbidden database. 939 // 940 if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha256Guid)) { 941 HashAlg = HASHALG_SHA256; 942 } else if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha384Guid)) { 943 HashAlg = HASHALG_SHA384; 944 } else if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha512Guid)) { 945 HashAlg = HASHALG_SHA512; 946 } else { 947 DbxSize -= DbxList->SignatureListSize; 948 DbxList = (EFI_SIGNATURE_LIST *) ((UINT8 *) DbxList + DbxList->SignatureListSize); 949 continue; 950 } 951 952 // 953 // Calculate the hash value of current TBSCertificate for comparision. 954 // 955 if (mHash[HashAlg].GetContextSize == NULL) { 956 goto Done; 957 } 958 ZeroMem (CertDigest, MAX_DIGEST_SIZE); 959 HashCtx = AllocatePool (mHash[HashAlg].GetContextSize ()); 960 if (HashCtx == NULL) { 961 goto Done; 962 } 963 Status = mHash[HashAlg].HashInit (HashCtx); 964 if (!Status) { 965 goto Done; 966 } 967 Status = mHash[HashAlg].HashUpdate (HashCtx, TBSCert, TBSCertSize); 968 if (!Status) { 969 goto Done; 970 } 971 Status = mHash[HashAlg].HashFinal (HashCtx, CertDigest); 972 if (!Status) { 973 goto Done; 974 } 975 976 SiglistHeaderSize = sizeof (EFI_SIGNATURE_LIST) + DbxList->SignatureHeaderSize; 977 CertHash = (EFI_SIGNATURE_DATA *) ((UINT8 *) DbxList + SiglistHeaderSize); 978 CertHashCount = (DbxList->SignatureListSize - SiglistHeaderSize) / DbxList->SignatureSize; 979 for (Index = 0; Index < CertHashCount; Index++) { 980 // 981 // Iterate each Signature Data Node within this CertList for verify. 982 // 983 DbxCertHash = CertHash->SignatureData; 984 if (CompareMem (DbxCertHash, CertDigest, mHash[HashAlg].DigestLength) == 0) { 985 // 986 // Hash of Certificate is found in forbidden database. 987 // 988 IsFound = TRUE; 989 990 // 991 // Return the revocation time. 992 // 993 CopyMem (RevocationTime, (EFI_TIME *)(DbxCertHash + mHash[HashAlg].DigestLength), sizeof (EFI_TIME)); 994 goto Done; 995 } 996 CertHash = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertHash + DbxList->SignatureSize); 997 } 998 999 DbxSize -= DbxList->SignatureListSize; 1000 DbxList = (EFI_SIGNATURE_LIST *) ((UINT8 *) DbxList + DbxList->SignatureListSize); 1001 } 1002 1003Done: 1004 if (HashCtx != NULL) { 1005 FreePool (HashCtx); 1006 } 1007 1008 return IsFound; 1009} 1010 1011/** 1012 Check whether signature is in specified database. 1013 1014 @param[in] VariableName Name of database variable that is searched in. 1015 @param[in] Signature Pointer to signature that is searched for. 1016 @param[in] CertType Pointer to hash algrithom. 1017 @param[in] SignatureSize Size of Signature. 1018 1019 @return TRUE Found the signature in the variable database. 1020 @return FALSE Not found the signature in the variable database. 1021 1022**/ 1023BOOLEAN 1024IsSignatureFoundInDatabase ( 1025 IN CHAR16 *VariableName, 1026 IN UINT8 *Signature, 1027 IN EFI_GUID *CertType, 1028 IN UINTN SignatureSize 1029 ) 1030{ 1031 EFI_STATUS Status; 1032 EFI_SIGNATURE_LIST *CertList; 1033 EFI_SIGNATURE_DATA *Cert; 1034 UINTN DataSize; 1035 UINT8 *Data; 1036 UINTN Index; 1037 UINTN CertCount; 1038 BOOLEAN IsFound; 1039 1040 // 1041 // Read signature database variable. 1042 // 1043 IsFound = FALSE; 1044 Data = NULL; 1045 DataSize = 0; 1046 Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL); 1047 if (Status != EFI_BUFFER_TOO_SMALL) { 1048 return FALSE; 1049 } 1050 1051 Data = (UINT8 *) AllocateZeroPool (DataSize); 1052 if (Data == NULL) { 1053 return FALSE; 1054 } 1055 1056 Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, Data); 1057 if (EFI_ERROR (Status)) { 1058 goto Done; 1059 } 1060 // 1061 // Enumerate all signature data in SigDB to check if executable's signature exists. 1062 // 1063 CertList = (EFI_SIGNATURE_LIST *) Data; 1064 while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) { 1065 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize; 1066 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize); 1067 if ((CertList->SignatureSize == sizeof(EFI_SIGNATURE_DATA) - 1 + SignatureSize) && (CompareGuid(&CertList->SignatureType, CertType))) { 1068 for (Index = 0; Index < CertCount; Index++) { 1069 if (CompareMem (Cert->SignatureData, Signature, SignatureSize) == 0) { 1070 // 1071 // Find the signature in database. 1072 // 1073 IsFound = TRUE; 1074 SecureBootHook (VariableName, &gEfiImageSecurityDatabaseGuid, CertList->SignatureSize, Cert); 1075 break; 1076 } 1077 1078 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize); 1079 } 1080 1081 if (IsFound) { 1082 break; 1083 } 1084 } 1085 1086 DataSize -= CertList->SignatureListSize; 1087 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize); 1088 } 1089 1090Done: 1091 if (Data != NULL) { 1092 FreePool (Data); 1093 } 1094 1095 return IsFound; 1096} 1097 1098/** 1099 Check whether the timestamp is valid by comparing the signing time and the revocation time. 1100 1101 @param SigningTime A pointer to the signing time. 1102 @param RevocationTime A pointer to the revocation time. 1103 1104 @retval TRUE The SigningTime is not later than the RevocationTime. 1105 @retval FALSE The SigningTime is later than the RevocationTime. 1106 1107**/ 1108BOOLEAN 1109IsValidSignatureByTimestamp ( 1110 IN EFI_TIME *SigningTime, 1111 IN EFI_TIME *RevocationTime 1112 ) 1113{ 1114 if (SigningTime->Year != RevocationTime->Year) { 1115 return (BOOLEAN) (SigningTime->Year < RevocationTime->Year); 1116 } else if (SigningTime->Month != RevocationTime->Month) { 1117 return (BOOLEAN) (SigningTime->Month < RevocationTime->Month); 1118 } else if (SigningTime->Day != RevocationTime->Day) { 1119 return (BOOLEAN) (SigningTime->Day < RevocationTime->Day); 1120 } else if (SigningTime->Hour != RevocationTime->Hour) { 1121 return (BOOLEAN) (SigningTime->Hour < RevocationTime->Hour); 1122 } else if (SigningTime->Minute != RevocationTime->Minute) { 1123 return (BOOLEAN) (SigningTime->Minute < RevocationTime->Minute); 1124 } 1125 1126 return (BOOLEAN) (SigningTime->Second <= RevocationTime->Second); 1127} 1128 1129/** 1130 Check if the given time value is zero. 1131 1132 @param[in] Time Pointer of a time value. 1133 1134 @retval TRUE The Time is Zero. 1135 @retval FALSE The Time is not Zero. 1136 1137**/ 1138BOOLEAN 1139IsTimeZero ( 1140 IN EFI_TIME *Time 1141 ) 1142{ 1143 if ((Time->Year == 0) && (Time->Month == 0) && (Time->Day == 0) && 1144 (Time->Hour == 0) && (Time->Minute == 0) && (Time->Second == 0)) { 1145 return TRUE; 1146 } 1147 1148 return FALSE; 1149} 1150 1151/** 1152 Record multiple certificate list & verification state of a verified image to 1153 IMAGE_EXECUTION_TABLE. 1154 1155 @param[in] CertBuf Certificate list buffer. 1156 @param[in] CertBufLength Certificate list buffer. 1157 @param[in] Action Certificate list action to be record. 1158 @param[in] ImageName Image name. 1159 @param[in] ImageDevicePath Image device path. 1160 1161**/ 1162VOID 1163RecordCertListToImageExeuctionTable( 1164 IN UINT8 *CertBuf, 1165 IN UINTN CertBufLength, 1166 IN EFI_IMAGE_EXECUTION_ACTION Action, 1167 IN CHAR16 *ImageName OPTIONAL, 1168 IN CONST EFI_DEVICE_PATH_PROTOCOL *ImageDevicePath OPTIONAL 1169 ) 1170{ 1171 UINT8 CertNumber; 1172 UINT8 *CertPtr; 1173 UINTN Index; 1174 UINT8 *Cert; 1175 UINTN CertSize; 1176 EFI_STATUS Status; 1177 EFI_SIGNATURE_LIST *SignatureList; 1178 UINTN SignatureListSize; 1179 1180 CertNumber = (UINT8) (*CertBuf); 1181 CertPtr = CertBuf + 1; 1182 for (Index = 0; Index < CertNumber; Index++) { 1183 CertSize = (UINTN) ReadUnaligned32 ((UINT32 *)CertPtr); 1184 Cert = (UINT8 *)CertPtr + sizeof (UINT32); 1185 1186 // 1187 // Record all cert in cert chain to be passed 1188 // 1189 Status = CreateSignatureList(Cert, CertSize, &gEfiCertX509Guid, &SignatureList, &SignatureListSize); 1190 if (!EFI_ERROR(Status)) { 1191 AddImageExeInfo (Action, ImageName, ImageDevicePath, SignatureList, SignatureListSize); 1192 FreePool (SignatureList); 1193 } 1194 } 1195} 1196 1197 1198/** 1199 Check whether the timestamp signature is valid and the signing time is also earlier than 1200 the revocation time. 1201 1202 @param[in] AuthData Pointer to the Authenticode signature retrieved from signed image. 1203 @param[in] AuthDataSize Size of the Authenticode signature in bytes. 1204 @param[in] RevocationTime The time that the certificate was revoked. 1205 1206 @retval TRUE Timestamp signature is valid and signing time is no later than the 1207 revocation time. 1208 @retval FALSE Timestamp signature is not valid or the signing time is later than the 1209 revocation time. 1210 1211**/ 1212BOOLEAN 1213PassTimestampCheck ( 1214 IN UINT8 *AuthData, 1215 IN UINTN AuthDataSize, 1216 IN EFI_TIME *RevocationTime 1217 ) 1218{ 1219 EFI_STATUS Status; 1220 BOOLEAN VerifyStatus; 1221 EFI_SIGNATURE_LIST *CertList; 1222 EFI_SIGNATURE_DATA *Cert; 1223 UINT8 *DbtData; 1224 UINTN DbtDataSize; 1225 UINT8 *RootCert; 1226 UINTN RootCertSize; 1227 UINTN Index; 1228 UINTN CertCount; 1229 EFI_TIME SigningTime; 1230 1231 // 1232 // Variable Initialization 1233 // 1234 VerifyStatus = FALSE; 1235 DbtData = NULL; 1236 CertList = NULL; 1237 Cert = NULL; 1238 RootCert = NULL; 1239 RootCertSize = 0; 1240 1241 // 1242 // If RevocationTime is zero, the certificate shall be considered to always be revoked. 1243 // 1244 if (IsTimeZero (RevocationTime)) { 1245 return FALSE; 1246 } 1247 1248 // 1249 // RevocationTime is non-zero, the certificate should be considered to be revoked from that time and onwards. 1250 // Using the dbt to get the trusted TSA certificates. 1251 // 1252 DbtDataSize = 0; 1253 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE2, &gEfiImageSecurityDatabaseGuid, NULL, &DbtDataSize, NULL); 1254 if (Status != EFI_BUFFER_TOO_SMALL) { 1255 goto Done; 1256 } 1257 DbtData = (UINT8 *) AllocateZeroPool (DbtDataSize); 1258 if (DbtData == NULL) { 1259 goto Done; 1260 } 1261 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE2, &gEfiImageSecurityDatabaseGuid, NULL, &DbtDataSize, (VOID *) DbtData); 1262 if (EFI_ERROR (Status)) { 1263 goto Done; 1264 } 1265 1266 CertList = (EFI_SIGNATURE_LIST *) DbtData; 1267 while ((DbtDataSize > 0) && (DbtDataSize >= CertList->SignatureListSize)) { 1268 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) { 1269 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize); 1270 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize; 1271 for (Index = 0; Index < CertCount; Index++) { 1272 // 1273 // Iterate each Signature Data Node within this CertList for verify. 1274 // 1275 RootCert = Cert->SignatureData; 1276 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID); 1277 // 1278 // Get the signing time if the timestamp signature is valid. 1279 // 1280 if (ImageTimestampVerify (AuthData, AuthDataSize, RootCert, RootCertSize, &SigningTime)) { 1281 // 1282 // The signer signature is valid only when the signing time is earlier than revocation time. 1283 // 1284 if (IsValidSignatureByTimestamp (&SigningTime, RevocationTime)) { 1285 VerifyStatus = TRUE; 1286 goto Done; 1287 } 1288 } 1289 Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize); 1290 } 1291 } 1292 DbtDataSize -= CertList->SignatureListSize; 1293 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize); 1294 } 1295 1296Done: 1297 if (DbtData != NULL) { 1298 FreePool (DbtData); 1299 } 1300 1301 return VerifyStatus; 1302} 1303 1304/** 1305 Check whether the image signature is forbidden by the forbidden database (dbx). 1306 The image is forbidden to load if any certificates for signing are revoked before signing time. 1307 1308 @param[in] AuthData Pointer to the Authenticode signature retrieved from the signed image. 1309 @param[in] AuthDataSize Size of the Authenticode signature in bytes. 1310 @param[in] IsAuditMode Whether system Secure Boot Mode is in AuditMode. 1311 @param[in] ImageName Name of the image to verify. 1312 @param[in] ImageDevicePath DevicePath of the image to verify. 1313 1314 @retval TRUE Image is forbidden by dbx. 1315 @retval FALSE Image is not forbidden by dbx. 1316 1317**/ 1318BOOLEAN 1319IsForbiddenByDbx ( 1320 IN UINT8 *AuthData, 1321 IN UINTN AuthDataSize, 1322 IN BOOLEAN IsAuditMode, 1323 IN CHAR16 *ImageName OPTIONAL, 1324 IN CONST EFI_DEVICE_PATH_PROTOCOL *ImageDevicePath OPTIONAL 1325 ) 1326{ 1327 EFI_STATUS Status; 1328 BOOLEAN IsForbidden; 1329 UINT8 *Data; 1330 UINTN DataSize; 1331 EFI_SIGNATURE_LIST *CertList; 1332 UINTN CertListSize; 1333 EFI_SIGNATURE_DATA *CertData; 1334 UINT8 *RootCert; 1335 UINTN RootCertSize; 1336 UINTN CertCount; 1337 UINTN Index; 1338 UINT8 *CertBuffer; 1339 UINTN BufferLength; 1340 UINT8 *TrustedCert; 1341 UINTN TrustedCertLength; 1342 UINT8 CertNumber; 1343 UINT8 *CertPtr; 1344 UINT8 *Cert; 1345 UINTN CertSize; 1346 EFI_TIME RevocationTime; 1347 UINT8 *SignerCert; 1348 UINTN SignerCertLength; 1349 UINT8 *UnchainCert; 1350 UINTN UnchainCertLength; 1351 // 1352 // Variable Initialization 1353 // 1354 IsForbidden = FALSE; 1355 Data = NULL; 1356 CertList = NULL; 1357 CertData = NULL; 1358 RootCert = NULL; 1359 RootCertSize = 0; 1360 Cert = NULL; 1361 CertBuffer = NULL; 1362 BufferLength = 0; 1363 TrustedCert = NULL; 1364 TrustedCertLength = 0; 1365 SignerCert = NULL; 1366 SignerCertLength = 0; 1367 UnchainCert = NULL; 1368 UnchainCertLength = 0; 1369 1370 // 1371 // The image will not be forbidden if dbx can't be got. 1372 // 1373 DataSize = 0; 1374 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL); 1375 if (Status != EFI_BUFFER_TOO_SMALL) { 1376 return IsForbidden; 1377 } 1378 Data = (UINT8 *) AllocateZeroPool (DataSize); 1379 if (Data == NULL) { 1380 return IsForbidden; 1381 } 1382 1383 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data); 1384 if (EFI_ERROR (Status)) { 1385 return IsForbidden; 1386 } 1387 1388 // 1389 // Verify image signature with RAW X509 certificates in DBX database. 1390 // If passed, the image will be forbidden. 1391 // 1392 CertList = (EFI_SIGNATURE_LIST *) Data; 1393 CertListSize = DataSize; 1394 while ((CertListSize > 0) && (CertListSize >= CertList->SignatureListSize)) { 1395 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) { 1396 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize); 1397 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize; 1398 1399 for (Index = 0; Index < CertCount; Index++) { 1400 // 1401 // Iterate each Signature Data Node within this CertList for verify. 1402 // 1403 RootCert = CertData->SignatureData; 1404 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID); 1405 1406 // 1407 // Call AuthenticodeVerify library to Verify Authenticode struct. 1408 // 1409 IsForbidden = AuthenticodeVerify ( 1410 AuthData, 1411 AuthDataSize, 1412 RootCert, 1413 RootCertSize, 1414 mImageDigest, 1415 mImageDigestSize 1416 ); 1417 if (IsForbidden) { 1418 SecureBootHook (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, CertList->SignatureSize, CertData); 1419 goto Done; 1420 } 1421 1422 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize); 1423 } 1424 } 1425 1426 CertListSize -= CertList->SignatureListSize; 1427 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize); 1428 } 1429 1430 // 1431 // Check X.509 Certificate Hash & Possible Timestamp. 1432 // 1433 1434 // 1435 // Retrieve the certificate stack from AuthData 1436 // The output CertStack format will be: 1437 // UINT8 CertNumber; 1438 // UINT32 Cert1Length; 1439 // UINT8 Cert1[]; 1440 // UINT32 Cert2Length; 1441 // UINT8 Cert2[]; 1442 // ... 1443 // UINT32 CertnLength; 1444 // UINT8 Certn[]; 1445 // 1446 Pkcs7GetSigners (AuthData, AuthDataSize, &CertBuffer, &BufferLength, &TrustedCert, &TrustedCertLength); 1447 if ((BufferLength == 0) || (CertBuffer == NULL)) { 1448 IsForbidden = TRUE; 1449 goto Done; 1450 } 1451 1452 // 1453 // Check if any hash of certificates embedded in AuthData is in the forbidden database. 1454 // 1455 CertNumber = (UINT8) (*CertBuffer); 1456 CertPtr = CertBuffer + 1; 1457 for (Index = 0; Index < CertNumber; Index++) { 1458 CertSize = (UINTN) ReadUnaligned32 ((UINT32 *)CertPtr); 1459 Cert = (UINT8 *)CertPtr + sizeof (UINT32); 1460 1461 if (IsCertHashFoundInDatabase (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data, DataSize, &RevocationTime)) { 1462 // 1463 // Check the timestamp signature and signing time to determine if the image can be trusted. 1464 // 1465 IsForbidden = TRUE; 1466 if (PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime)) { 1467 IsForbidden = FALSE; 1468 } 1469 goto Done; 1470 } 1471 1472 CertPtr = CertPtr + sizeof (UINT32) + CertSize; 1473 } 1474 1475Done: 1476 if (IsForbidden && IsAuditMode) { 1477 Pkcs7GetCertificatesList(AuthData, AuthDataSize, &SignerCert, &SignerCertLength, &UnchainCert, &UnchainCertLength); 1478 1479 // 1480 // Record all certs in image to be failed 1481 // 1482 if ((SignerCertLength != 0) && (SignerCert != NULL)) { 1483 RecordCertListToImageExeuctionTable( 1484 SignerCert, 1485 SignerCertLength, 1486 EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED | EFI_IMAGE_EXECUTION_INITIALIZED, 1487 ImageName, 1488 ImageDevicePath 1489 ); 1490 } 1491 1492 if ((UnchainCertLength != 0) && (UnchainCert != NULL)) { 1493 RecordCertListToImageExeuctionTable( 1494 UnchainCert, 1495 UnchainCertLength, 1496 EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED | EFI_IMAGE_EXECUTION_INITIALIZED, 1497 ImageName, 1498 ImageDevicePath 1499 ); 1500 } 1501 } 1502 1503 if (Data != NULL) { 1504 FreePool (Data); 1505 } 1506 1507 Pkcs7FreeSigners (CertBuffer); 1508 Pkcs7FreeSigners (TrustedCert); 1509 Pkcs7FreeSigners (SignerCert); 1510 Pkcs7FreeSigners (UnchainCert); 1511 1512 return IsForbidden; 1513} 1514 1515 1516/** 1517 Check whether the image signature can be verified by the trusted certificates in DB database. 1518 1519 @param[in] AuthData Pointer to the Authenticode signature retrieved from signed image. 1520 @param[in] AuthDataSize Size of the Authenticode signature in bytes. 1521 @param[in] IsAuditMode Whether system Secure Boot Mode is in AuditMode. 1522 @param[in] ImageName Name of the image to verify. 1523 @param[in] ImageDevicePath DevicePath of the image to verify. 1524 1525 @retval TRUE Image passed verification using certificate in db. 1526 @retval FALSE Image didn't pass verification using certificate in db. 1527 1528**/ 1529BOOLEAN 1530IsAllowedByDb ( 1531 IN UINT8 *AuthData, 1532 IN UINTN AuthDataSize, 1533 IN BOOLEAN IsAuditMode, 1534 IN CHAR16 *ImageName OPTIONAL, 1535 IN CONST EFI_DEVICE_PATH_PROTOCOL *ImageDevicePath OPTIONAL 1536 ) 1537{ 1538 EFI_STATUS Status; 1539 BOOLEAN VerifyStatus; 1540 EFI_SIGNATURE_LIST *CertList; 1541 EFI_SIGNATURE_DATA *CertData; 1542 UINTN DataSize; 1543 UINT8 *Data; 1544 UINT8 *RootCert; 1545 UINTN RootCertSize; 1546 UINTN Index; 1547 UINTN CertCount; 1548 UINTN DbxDataSize; 1549 UINT8 *DbxData; 1550 EFI_TIME RevocationTime; 1551 UINT8 *SignerCert; 1552 UINTN SignerCertLength; 1553 UINT8 *UnchainCert; 1554 UINTN UnchainCertLength; 1555 1556 Data = NULL; 1557 CertList = NULL; 1558 CertData = NULL; 1559 RootCert = NULL; 1560 DbxData = NULL; 1561 RootCertSize = 0; 1562 VerifyStatus = FALSE; 1563 SignerCert = NULL; 1564 SignerCertLength = 0; 1565 UnchainCert = NULL; 1566 UnchainCertLength = 0; 1567 1568 DataSize = 0; 1569 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL); 1570 if (Status == EFI_BUFFER_TOO_SMALL) { 1571 Data = (UINT8 *) AllocateZeroPool (DataSize); 1572 if (Data == NULL) { 1573 return VerifyStatus; 1574 } 1575 1576 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data); 1577 if (EFI_ERROR (Status)) { 1578 goto Done; 1579 } 1580 1581 // 1582 // Find X509 certificate in Signature List to verify the signature in pkcs7 signed data. 1583 // 1584 CertList = (EFI_SIGNATURE_LIST *) Data; 1585 while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) { 1586 if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) { 1587 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize); 1588 CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize; 1589 1590 for (Index = 0; Index < CertCount; Index++) { 1591 // 1592 // Iterate each Signature Data Node within this CertList for verify. 1593 // 1594 RootCert = CertData->SignatureData; 1595 RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID); 1596 1597 // 1598 // Call AuthenticodeVerify library to Verify Authenticode struct. 1599 // 1600 VerifyStatus = AuthenticodeVerify ( 1601 AuthData, 1602 AuthDataSize, 1603 RootCert, 1604 RootCertSize, 1605 mImageDigest, 1606 mImageDigestSize 1607 ); 1608 if (VerifyStatus) { 1609 // 1610 // Here We still need to check if this RootCert's Hash is revoked 1611 // 1612 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, NULL); 1613 if (Status == EFI_BUFFER_TOO_SMALL) { 1614 goto Done; 1615 } 1616 DbxData = (UINT8 *) AllocateZeroPool (DbxDataSize); 1617 if (DbxData == NULL) { 1618 goto Done; 1619 } 1620 1621 Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, (VOID *) DbxData); 1622 if (EFI_ERROR (Status)) { 1623 goto Done; 1624 } 1625 1626 if (IsCertHashFoundInDatabase (RootCert, RootCertSize, (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime)) { 1627 // 1628 // Check the timestamp signature and signing time to determine if the image can be trusted. 1629 // 1630 VerifyStatus = PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime); 1631 } 1632 1633 goto Done; 1634 } 1635 1636 CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize); 1637 } 1638 } 1639 1640 DataSize -= CertList->SignatureListSize; 1641 CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize); 1642 } 1643 } 1644 1645Done: 1646 1647 if (VerifyStatus) { 1648 SecureBootHook (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, CertList->SignatureSize, CertData); 1649 } 1650 1651 if (IsAuditMode) { 1652 1653 Pkcs7GetCertificatesList(AuthData, AuthDataSize, &SignerCert, &SignerCertLength, &UnchainCert, &UnchainCertLength); 1654 if (VerifyStatus) { 1655 if ((SignerCertLength != 0) && (SignerCert != NULL)) { 1656 // 1657 // Record all cert in signer's cert chain to be passed 1658 // 1659 RecordCertListToImageExeuctionTable( 1660 SignerCert, 1661 SignerCertLength, 1662 EFI_IMAGE_EXECUTION_AUTH_SIG_PASSED | EFI_IMAGE_EXECUTION_INITIALIZED, 1663 ImageName, 1664 ImageDevicePath 1665 ); 1666 } 1667 1668 if ((UnchainCertLength != 0) && (UnchainCert != NULL)) { 1669 // 1670 // Record all certs in unchained certificates lists to be failed 1671 // 1672 RecordCertListToImageExeuctionTable( 1673 UnchainCert, 1674 UnchainCertLength, 1675 EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED | EFI_IMAGE_EXECUTION_INITIALIZED, 1676 ImageName, 1677 ImageDevicePath 1678 ); 1679 } 1680 } else { 1681 // 1682 // Record all certs in image to be failed 1683 // 1684 if ((SignerCertLength != 0) && (SignerCert != NULL)) { 1685 RecordCertListToImageExeuctionTable( 1686 SignerCert, 1687 SignerCertLength, 1688 EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED | EFI_IMAGE_EXECUTION_INITIALIZED, 1689 ImageName, 1690 ImageDevicePath 1691 ); 1692 } 1693 1694 if ((UnchainCertLength != 0) && (UnchainCert != NULL)) { 1695 RecordCertListToImageExeuctionTable( 1696 UnchainCert, 1697 UnchainCertLength, 1698 EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED | EFI_IMAGE_EXECUTION_INITIALIZED, 1699 ImageName, 1700 ImageDevicePath 1701 ); 1702 } 1703 } 1704 } 1705 1706 1707 if (Data != NULL) { 1708 FreePool (Data); 1709 } 1710 if (DbxData != NULL) { 1711 FreePool (DbxData); 1712 } 1713 1714 Pkcs7FreeSigners (SignerCert); 1715 Pkcs7FreeSigners (UnchainCert); 1716 1717 return VerifyStatus; 1718} 1719 1720/** 1721 Provide verification service for signed images in AuditMode, which include both signature validation 1722 and platform policy control. For signature types, both UEFI WIN_CERTIFICATE_UEFI_GUID and 1723 MSFT Authenticode type signatures are supported. 1724 1725 In this implementation, only verify external executables when in AuditMode. 1726 Executables from FV is bypass, so pass in AuthenticationStatus is ignored. Other authentication status 1727 are record into IMAGE_EXECUTION_TABLE. 1728 1729 The image verification policy is: 1730 If the image is signed, 1731 At least one valid signature or at least one hash value of the image must match a record 1732 in the security database "db", and no valid signature nor any hash value of the image may 1733 be reflected in the security database "dbx". 1734 Otherwise, the image is not signed, 1735 The SHA256 hash value of the image must match a record in the security database "db", and 1736 not be reflected in the security data base "dbx". 1737 1738 Caution: This function may receive untrusted input. 1739 PE/COFF image is external input, so this function will validate its data structure 1740 within this image buffer before use. 1741 1742 @param[in] AuthenticationStatus 1743 This is the authentication status returned from the security 1744 measurement services for the input file. 1745 @param[in] File This is a pointer to the device path of the file that is 1746 being dispatched. This will optionally be used for logging. 1747 @param[in] FileBuffer File buffer matches the input file device path. 1748 @param[in] FileSize Size of File buffer matches the input file device path. 1749 @param[in] BootPolicy A boot policy that was used to call LoadImage() UEFI service. 1750 1751 @retval EFI_SUCCESS The authenticate info is sucessfully stored for the file 1752 specified by DevicePath and non-NULL FileBuffer 1753 @retval EFI_ACCESS_DENIED The file specified by File and FileBuffer did not 1754 authenticate, and the platform policy dictates that the DXE 1755 Foundation many not use File. 1756 1757**/ 1758EFI_STATUS 1759EFIAPI 1760ImageVerificationInAuditMode ( 1761 IN UINT32 AuthenticationStatus, 1762 IN CONST EFI_DEVICE_PATH_PROTOCOL *File, 1763 IN VOID *FileBuffer, 1764 IN UINTN FileSize, 1765 IN BOOLEAN BootPolicy 1766 ) 1767{ 1768 EFI_STATUS Status; 1769 UINT16 Magic; 1770 EFI_IMAGE_DOS_HEADER *DosHdr; 1771 EFI_SIGNATURE_LIST *SignatureList; 1772 EFI_IMAGE_EXECUTION_ACTION Action; 1773 WIN_CERTIFICATE *WinCertificate; 1774 UINT32 Policy; 1775 PE_COFF_LOADER_IMAGE_CONTEXT ImageContext; 1776 UINT32 NumberOfRvaAndSizes; 1777 WIN_CERTIFICATE_EFI_PKCS *PkcsCertData; 1778 WIN_CERTIFICATE_UEFI_GUID *WinCertUefiGuid; 1779 UINT8 *AuthData; 1780 UINTN AuthDataSize; 1781 EFI_IMAGE_DATA_DIRECTORY *SecDataDir; 1782 UINT32 OffSet; 1783 CHAR16 *FilePathStr; 1784 UINTN SignatureListSize; 1785 1786 SignatureList = NULL; 1787 WinCertificate = NULL; 1788 SecDataDir = NULL; 1789 PkcsCertData = NULL; 1790 FilePathStr = NULL; 1791 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED | EFI_IMAGE_EXECUTION_INITIALIZED; 1792 Status = EFI_ACCESS_DENIED; 1793 1794 1795 // 1796 // Check the image type and get policy setting. 1797 // 1798 switch (GetImageType (File)) { 1799 1800 case IMAGE_FROM_FV: 1801 Policy = ALWAYS_EXECUTE; 1802 break; 1803 1804 case IMAGE_FROM_OPTION_ROM: 1805 Policy = PcdGet32 (PcdOptionRomImageVerificationPolicy); 1806 break; 1807 1808 case IMAGE_FROM_REMOVABLE_MEDIA: 1809 Policy = PcdGet32 (PcdRemovableMediaImageVerificationPolicy); 1810 break; 1811 1812 case IMAGE_FROM_FIXED_MEDIA: 1813 Policy = PcdGet32 (PcdFixedMediaImageVerificationPolicy); 1814 break; 1815 1816 default: 1817 Policy = DENY_EXECUTE_ON_SECURITY_VIOLATION; 1818 break; 1819 } 1820 1821 // 1822 // If policy is always/never execute, return directly. 1823 // 1824 if (Policy == ALWAYS_EXECUTE) { 1825 return EFI_SUCCESS; 1826 } 1827 1828 // 1829 // Get Image Device Path Str 1830 // 1831 FilePathStr = ConvertDevicePathToText (File, FALSE, TRUE); 1832 1833 // 1834 // Authentication failed because of (unspecified) firmware security policy 1835 // 1836 if (Policy == NEVER_EXECUTE) { 1837 // 1838 // No signature, record FilePath/FilePathStr only 1839 // 1840 AddImageExeInfo (EFI_IMAGE_EXECUTION_POLICY_FAILED | EFI_IMAGE_EXECUTION_INITIALIZED, FilePathStr, File, NULL, 0); 1841 goto END; 1842 } 1843 1844 // 1845 // The policy QUERY_USER_ON_SECURITY_VIOLATION and ALLOW_EXECUTE_ON_SECURITY_VIOLATION 1846 // violates the UEFI spec and has been removed. 1847 // 1848 ASSERT (Policy != QUERY_USER_ON_SECURITY_VIOLATION && Policy != ALLOW_EXECUTE_ON_SECURITY_VIOLATION); 1849 if (Policy == QUERY_USER_ON_SECURITY_VIOLATION || Policy == ALLOW_EXECUTE_ON_SECURITY_VIOLATION) { 1850 CpuDeadLoop (); 1851 } 1852 1853 // 1854 // Read the Dos header. 1855 // 1856 if (FileBuffer == NULL) { 1857 Status = EFI_INVALID_PARAMETER; 1858 goto END; 1859 } 1860 1861 mImageBase = (UINT8 *) FileBuffer; 1862 mImageSize = FileSize; 1863 1864 ZeroMem (&ImageContext, sizeof (ImageContext)); 1865 ImageContext.Handle = (VOID *) FileBuffer; 1866 ImageContext.ImageRead = (PE_COFF_LOADER_READ_FILE) DxeImageVerificationLibImageRead; 1867 1868 // 1869 // Get information about the image being loaded 1870 // 1871 Status = PeCoffLoaderGetImageInfo (&ImageContext); 1872 if (EFI_ERROR (Status)) { 1873 // 1874 // The information can't be got from the invalid PeImage 1875 // 1876 goto END; 1877 } 1878 1879 1880 DosHdr = (EFI_IMAGE_DOS_HEADER *) mImageBase; 1881 if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) { 1882 // 1883 // DOS image header is present, 1884 // so read the PE header after the DOS image header. 1885 // 1886 mPeCoffHeaderOffset = DosHdr->e_lfanew; 1887 } else { 1888 mPeCoffHeaderOffset = 0; 1889 } 1890 1891 // 1892 // Check PE/COFF image. 1893 // 1894 mNtHeader.Pe32 = (EFI_IMAGE_NT_HEADERS32 *) (mImageBase + mPeCoffHeaderOffset); 1895 if (mNtHeader.Pe32->Signature != EFI_IMAGE_NT_SIGNATURE) { 1896 // 1897 // It is not a valid Pe/Coff file. 1898 // 1899 Status = EFI_ACCESS_DENIED; 1900 goto END; 1901 } 1902 1903 if (mNtHeader.Pe32->FileHeader.Machine == IMAGE_FILE_MACHINE_IA64 && mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) { 1904 // 1905 // NOTE: Some versions of Linux ELILO for Itanium have an incorrect magic value 1906 // in the PE/COFF Header. If the MachineType is Itanium(IA64) and the 1907 // Magic value in the OptionalHeader is EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC 1908 // then override the magic value to EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC 1909 // 1910 Magic = EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC; 1911 } else { 1912 // 1913 // Get the magic value from the PE/COFF Optional Header 1914 // 1915 Magic = mNtHeader.Pe32->OptionalHeader.Magic; 1916 } 1917 1918 if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) { 1919 // 1920 // Use PE32 offset. 1921 // 1922 NumberOfRvaAndSizes = mNtHeader.Pe32->OptionalHeader.NumberOfRvaAndSizes; 1923 if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) { 1924 SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]; 1925 } 1926 } else { 1927 // 1928 // Use PE32+ offset. 1929 // 1930 NumberOfRvaAndSizes = mNtHeader.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes; 1931 if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) { 1932 SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]; 1933 } 1934 } 1935 1936 // 1937 // Start Image Validation. 1938 // 1939 if (SecDataDir == NULL || SecDataDir->Size == 0) { 1940 // 1941 // This image is not signed. The SHA256 hash value of the image must match a record in the security database "db", 1942 // and not be reflected in the security data base "dbx". 1943 // 1944 if (!HashPeImage (HASHALG_SHA256)) { 1945 Status = EFI_ACCESS_DENIED; 1946 goto END; 1947 } 1948 1949 // 1950 // Image Hash is in forbidden database (DBX). 1951 // 1952 if (!IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) { 1953 // 1954 // Image Hash is in allowed database (DB). 1955 // 1956 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) { 1957 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_PASSED | EFI_IMAGE_EXECUTION_INITIALIZED; 1958 } 1959 } 1960 1961 // 1962 // Add HASH digest for image without signature 1963 // 1964 Status = CreateSignatureList(mImageDigest, mImageDigestSize, &mCertType, &SignatureList, &SignatureListSize); 1965 if (!EFI_ERROR(Status)) { 1966 AddImageExeInfo (Action, FilePathStr, File, SignatureList, SignatureListSize); 1967 FreePool (SignatureList); 1968 } 1969 goto END; 1970 } 1971 1972 // 1973 // Verify the signature of the image, multiple signatures are allowed as per PE/COFF Section 4.7 1974 // "Attribute Certificate Table". 1975 // The first certificate starts at offset (SecDataDir->VirtualAddress) from the start of the file. 1976 // 1977 for (OffSet = SecDataDir->VirtualAddress; 1978 OffSet < (SecDataDir->VirtualAddress + SecDataDir->Size); 1979 OffSet += (WinCertificate->dwLength + ALIGN_SIZE (WinCertificate->dwLength))) { 1980 WinCertificate = (WIN_CERTIFICATE *) (mImageBase + OffSet); 1981 if ((SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) <= sizeof (WIN_CERTIFICATE) || 1982 (SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) < WinCertificate->dwLength) { 1983 break; 1984 } 1985 1986 // 1987 // Verify the image's Authenticode signature, only DER-encoded PKCS#7 signed data is supported. 1988 // 1989 if (WinCertificate->wCertificateType == WIN_CERT_TYPE_PKCS_SIGNED_DATA) { 1990 // 1991 // The certificate is formatted as WIN_CERTIFICATE_EFI_PKCS which is described in the 1992 // Authenticode specification. 1993 // 1994 PkcsCertData = (WIN_CERTIFICATE_EFI_PKCS *) WinCertificate; 1995 if (PkcsCertData->Hdr.dwLength <= sizeof (PkcsCertData->Hdr)) { 1996 break; 1997 } 1998 AuthData = PkcsCertData->CertData; 1999 AuthDataSize = PkcsCertData->Hdr.dwLength - sizeof(PkcsCertData->Hdr); 2000 } else if (WinCertificate->wCertificateType == WIN_CERT_TYPE_EFI_GUID) { 2001 // 2002 // The certificate is formatted as WIN_CERTIFICATE_UEFI_GUID which is described in UEFI Spec. 2003 // 2004 WinCertUefiGuid = (WIN_CERTIFICATE_UEFI_GUID *) WinCertificate; 2005 if (WinCertUefiGuid->Hdr.dwLength <= OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData)) { 2006 break; 2007 } 2008 if (!CompareGuid (&WinCertUefiGuid->CertType, &gEfiCertPkcs7Guid)) { 2009 continue; 2010 } 2011 AuthData = WinCertUefiGuid->CertData; 2012 AuthDataSize = WinCertUefiGuid->Hdr.dwLength - OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData); 2013 } else { 2014 if (WinCertificate->dwLength < sizeof (WIN_CERTIFICATE)) { 2015 break; 2016 } 2017 continue; 2018 } 2019 2020 Status = HashPeImageByType (AuthData, AuthDataSize); 2021 if (EFI_ERROR (Status)) { 2022 continue; 2023 } 2024 2025 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED | EFI_IMAGE_EXECUTION_INITIALIZED; 2026 2027 // 2028 // Check the digital signature against the revoked certificate in forbidden database (dbx). 2029 // Check the digital signature against the valid certificate in allowed database (db). 2030 // 2031 if (!IsForbiddenByDbx (AuthData, AuthDataSize, TRUE, FilePathStr, File)) { 2032 IsAllowedByDb (AuthData, AuthDataSize, TRUE, FilePathStr, File); 2033 } 2034 2035 // 2036 // Check the image's hash value. 2037 // 2038 if (!IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) { 2039 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) { 2040 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_PASSED | EFI_IMAGE_EXECUTION_INITIALIZED; 2041 } 2042 } 2043 2044 // 2045 // Add HASH digest for image with signature 2046 // 2047 Status = CreateSignatureList(mImageDigest, mImageDigestSize, &mCertType, &SignatureList, &SignatureListSize); 2048 2049 if (!EFI_ERROR(Status)) { 2050 AddImageExeInfo (Action, FilePathStr, File, SignatureList, SignatureListSize); 2051 FreePool (SignatureList); 2052 } else { 2053 goto END; 2054 } 2055 } 2056 2057 2058 if (OffSet != (SecDataDir->VirtualAddress + SecDataDir->Size)) { 2059 // 2060 // The Size in Certificate Table or the attribute certicate table is corrupted. 2061 // 2062 Status = EFI_ACCESS_DENIED; 2063 } else { 2064 Status = EFI_SUCCESS; 2065 } 2066 2067END: 2068 2069 if (FilePathStr != NULL) { 2070 FreePool(FilePathStr); 2071 FilePathStr = NULL; 2072 } 2073 2074 return Status; 2075} 2076 2077/** 2078 Provide verification service for signed images, which include both signature validation 2079 and platform policy control. For signature types, both UEFI WIN_CERTIFICATE_UEFI_GUID and 2080 MSFT Authenticode type signatures are supported. 2081 2082 In this implementation, only verify external executables when in USER MODE. 2083 Executables from FV is bypass, so pass in AuthenticationStatus is ignored. 2084 2085 The image verification policy is: 2086 If the image is signed, 2087 At least one valid signature or at least one hash value of the image must match a record 2088 in the security database "db", and no valid signature nor any hash value of the image may 2089 be reflected in the security database "dbx". 2090 Otherwise, the image is not signed, 2091 The SHA256 hash value of the image must match a record in the security database "db", and 2092 not be reflected in the security data base "dbx". 2093 2094 Caution: This function may receive untrusted input. 2095 PE/COFF image is external input, so this function will validate its data structure 2096 within this image buffer before use. 2097 2098 @param[in] AuthenticationStatus 2099 This is the authentication status returned from the security 2100 measurement services for the input file. 2101 @param[in] File This is a pointer to the device path of the file that is 2102 being dispatched. This will optionally be used for logging. 2103 @param[in] FileBuffer File buffer matches the input file device path. 2104 @param[in] FileSize Size of File buffer matches the input file device path. 2105 @param[in] BootPolicy A boot policy that was used to call LoadImage() UEFI service. 2106 2107 @retval EFI_SUCCESS The file specified by DevicePath and non-NULL 2108 FileBuffer did authenticate, and the platform policy dictates 2109 that the DXE Foundation may use the file. 2110 @retval EFI_SUCCESS The device path specified by NULL device path DevicePath 2111 and non-NULL FileBuffer did authenticate, and the platform 2112 policy dictates that the DXE Foundation may execute the image in 2113 FileBuffer. 2114 @retval EFI_OUT_RESOURCE Fail to allocate memory. 2115 @retval EFI_SECURITY_VIOLATION The file specified by File did not authenticate, and 2116 the platform policy dictates that File should be placed 2117 in the untrusted state. The image has been added to the file 2118 execution table. 2119 @retval EFI_ACCESS_DENIED The file specified by File and FileBuffer did not 2120 authenticate, and the platform policy dictates that the DXE 2121 Foundation many not use File. 2122 2123**/ 2124EFI_STATUS 2125EFIAPI 2126DxeImageVerificationHandler ( 2127 IN UINT32 AuthenticationStatus, 2128 IN CONST EFI_DEVICE_PATH_PROTOCOL *File, 2129 IN VOID *FileBuffer, 2130 IN UINTN FileSize, 2131 IN BOOLEAN BootPolicy 2132 ) 2133{ 2134 EFI_STATUS Status; 2135 UINT16 Magic; 2136 EFI_IMAGE_DOS_HEADER *DosHdr; 2137 EFI_STATUS VerifyStatus; 2138 EFI_SIGNATURE_LIST *SignatureList; 2139 UINTN SignatureListSize; 2140 EFI_SIGNATURE_DATA *Signature; 2141 EFI_IMAGE_EXECUTION_ACTION Action; 2142 WIN_CERTIFICATE *WinCertificate; 2143 UINT32 Policy; 2144 UINT8 *VarData; 2145 UINT8 SecureBoot; 2146 UINT8 AuditMode; 2147 PE_COFF_LOADER_IMAGE_CONTEXT ImageContext; 2148 UINT32 NumberOfRvaAndSizes; 2149 WIN_CERTIFICATE_EFI_PKCS *PkcsCertData; 2150 WIN_CERTIFICATE_UEFI_GUID *WinCertUefiGuid; 2151 UINT8 *AuthData; 2152 UINTN AuthDataSize; 2153 EFI_IMAGE_DATA_DIRECTORY *SecDataDir; 2154 UINT32 OffSet; 2155 CHAR16 *NameStr; 2156 2157 SignatureList = NULL; 2158 SignatureListSize = 0; 2159 WinCertificate = NULL; 2160 SecDataDir = NULL; 2161 PkcsCertData = NULL; 2162 Action = EFI_IMAGE_EXECUTION_AUTH_UNTESTED; 2163 Status = EFI_ACCESS_DENIED; 2164 VerifyStatus = EFI_ACCESS_DENIED; 2165 2166 GetEfiGlobalVariable2 (EFI_AUDIT_MODE_NAME, (VOID**)&VarData, NULL); 2167 // 2168 // Skip verification if AuditMode variable doesn't exist. AuditMode should always exist 2169 // 2170 if (VarData == NULL) { 2171 return EFI_SUCCESS; 2172 } 2173 AuditMode = *VarData; 2174 FreePool(VarData); 2175 2176 if (AuditMode == AUDIT_MODE_ENABLE) { 2177 return ImageVerificationInAuditMode(AuthenticationStatus, File, FileBuffer, FileSize, BootPolicy); 2178 } 2179 2180 // 2181 // Check the image type and get policy setting. 2182 // 2183 switch (GetImageType (File)) { 2184 2185 case IMAGE_FROM_FV: 2186 Policy = ALWAYS_EXECUTE; 2187 break; 2188 2189 case IMAGE_FROM_OPTION_ROM: 2190 Policy = PcdGet32 (PcdOptionRomImageVerificationPolicy); 2191 break; 2192 2193 case IMAGE_FROM_REMOVABLE_MEDIA: 2194 Policy = PcdGet32 (PcdRemovableMediaImageVerificationPolicy); 2195 break; 2196 2197 case IMAGE_FROM_FIXED_MEDIA: 2198 Policy = PcdGet32 (PcdFixedMediaImageVerificationPolicy); 2199 break; 2200 2201 default: 2202 Policy = DENY_EXECUTE_ON_SECURITY_VIOLATION; 2203 break; 2204 } 2205 // 2206 // If policy is always/never execute, return directly. 2207 // 2208 if (Policy == ALWAYS_EXECUTE) { 2209 return EFI_SUCCESS; 2210 } else if (Policy == NEVER_EXECUTE) { 2211 return EFI_ACCESS_DENIED; 2212 } 2213 2214 // 2215 // The policy QUERY_USER_ON_SECURITY_VIOLATION and ALLOW_EXECUTE_ON_SECURITY_VIOLATION 2216 // violates the UEFI spec and has been removed. 2217 // 2218 ASSERT (Policy != QUERY_USER_ON_SECURITY_VIOLATION && Policy != ALLOW_EXECUTE_ON_SECURITY_VIOLATION); 2219 if (Policy == QUERY_USER_ON_SECURITY_VIOLATION || Policy == ALLOW_EXECUTE_ON_SECURITY_VIOLATION) { 2220 CpuDeadLoop (); 2221 } 2222 2223 GetEfiGlobalVariable2 (EFI_SECURE_BOOT_MODE_NAME, (VOID**)&VarData, NULL); 2224 // 2225 // Skip verification if SecureBoot variable doesn't exist. 2226 // 2227 if (VarData == NULL) { 2228 return EFI_SUCCESS; 2229 } 2230 SecureBoot = *VarData; 2231 FreePool(VarData); 2232 2233 // 2234 // Skip verification if SecureBoot is disabled but not AuditMode 2235 // 2236 if (SecureBoot == SECURE_BOOT_MODE_DISABLE) { 2237 return EFI_SUCCESS; 2238 } 2239 2240 // 2241 // Read the Dos header. 2242 // 2243 if (FileBuffer == NULL) { 2244 return EFI_INVALID_PARAMETER; 2245 } 2246 2247 mImageBase = (UINT8 *) FileBuffer; 2248 mImageSize = FileSize; 2249 2250 ZeroMem (&ImageContext, sizeof (ImageContext)); 2251 ImageContext.Handle = (VOID *) FileBuffer; 2252 ImageContext.ImageRead = (PE_COFF_LOADER_READ_FILE) DxeImageVerificationLibImageRead; 2253 2254 // 2255 // Get information about the image being loaded 2256 // 2257 Status = PeCoffLoaderGetImageInfo (&ImageContext); 2258 if (EFI_ERROR (Status)) { 2259 // 2260 // The information can't be got from the invalid PeImage 2261 // 2262 goto Done; 2263 } 2264 2265 Status = EFI_ACCESS_DENIED; 2266 2267 DosHdr = (EFI_IMAGE_DOS_HEADER *) mImageBase; 2268 if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) { 2269 // 2270 // DOS image header is present, 2271 // so read the PE header after the DOS image header. 2272 // 2273 mPeCoffHeaderOffset = DosHdr->e_lfanew; 2274 } else { 2275 mPeCoffHeaderOffset = 0; 2276 } 2277 // 2278 // Check PE/COFF image. 2279 // 2280 mNtHeader.Pe32 = (EFI_IMAGE_NT_HEADERS32 *) (mImageBase + mPeCoffHeaderOffset); 2281 if (mNtHeader.Pe32->Signature != EFI_IMAGE_NT_SIGNATURE) { 2282 // 2283 // It is not a valid Pe/Coff file. 2284 // 2285 goto Done; 2286 } 2287 2288 if (mNtHeader.Pe32->FileHeader.Machine == IMAGE_FILE_MACHINE_IA64 && mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) { 2289 // 2290 // NOTE: Some versions of Linux ELILO for Itanium have an incorrect magic value 2291 // in the PE/COFF Header. If the MachineType is Itanium(IA64) and the 2292 // Magic value in the OptionalHeader is EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC 2293 // then override the magic value to EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC 2294 // 2295 Magic = EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC; 2296 } else { 2297 // 2298 // Get the magic value from the PE/COFF Optional Header 2299 // 2300 Magic = mNtHeader.Pe32->OptionalHeader.Magic; 2301 } 2302 2303 if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) { 2304 // 2305 // Use PE32 offset. 2306 // 2307 NumberOfRvaAndSizes = mNtHeader.Pe32->OptionalHeader.NumberOfRvaAndSizes; 2308 if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) { 2309 SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]; 2310 } 2311 } else { 2312 // 2313 // Use PE32+ offset. 2314 // 2315 NumberOfRvaAndSizes = mNtHeader.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes; 2316 if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) { 2317 SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]; 2318 } 2319 } 2320 2321 // 2322 // Start Image Validation. 2323 // 2324 if (SecDataDir == NULL || SecDataDir->Size == 0) { 2325 // 2326 // This image is not signed. The SHA256 hash value of the image must match a record in the security database "db", 2327 // and not be reflected in the security data base "dbx". 2328 // 2329 if (!HashPeImage (HASHALG_SHA256)) { 2330 goto Done; 2331 } 2332 2333 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) { 2334 // 2335 // Image Hash is in forbidden database (DBX). 2336 // 2337 goto Done; 2338 } 2339 2340 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) { 2341 // 2342 // Image Hash is in allowed database (DB). 2343 // 2344 return EFI_SUCCESS; 2345 } 2346 2347 // 2348 // Image Hash is not found in both forbidden and allowed database. 2349 // 2350 goto Done; 2351 } 2352 2353 // 2354 // Verify the signature of the image, multiple signatures are allowed as per PE/COFF Section 4.7 2355 // "Attribute Certificate Table". 2356 // The first certificate starts at offset (SecDataDir->VirtualAddress) from the start of the file. 2357 // 2358 for (OffSet = SecDataDir->VirtualAddress; 2359 OffSet < (SecDataDir->VirtualAddress + SecDataDir->Size); 2360 OffSet += (WinCertificate->dwLength + ALIGN_SIZE (WinCertificate->dwLength))) { 2361 WinCertificate = (WIN_CERTIFICATE *) (mImageBase + OffSet); 2362 if ((SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) <= sizeof (WIN_CERTIFICATE) || 2363 (SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) < WinCertificate->dwLength) { 2364 break; 2365 } 2366 2367 // 2368 // Verify the image's Authenticode signature, only DER-encoded PKCS#7 signed data is supported. 2369 // 2370 if (WinCertificate->wCertificateType == WIN_CERT_TYPE_PKCS_SIGNED_DATA) { 2371 // 2372 // The certificate is formatted as WIN_CERTIFICATE_EFI_PKCS which is described in the 2373 // Authenticode specification. 2374 // 2375 PkcsCertData = (WIN_CERTIFICATE_EFI_PKCS *) WinCertificate; 2376 if (PkcsCertData->Hdr.dwLength <= sizeof (PkcsCertData->Hdr)) { 2377 break; 2378 } 2379 AuthData = PkcsCertData->CertData; 2380 AuthDataSize = PkcsCertData->Hdr.dwLength - sizeof(PkcsCertData->Hdr); 2381 } else if (WinCertificate->wCertificateType == WIN_CERT_TYPE_EFI_GUID) { 2382 // 2383 // The certificate is formatted as WIN_CERTIFICATE_UEFI_GUID which is described in UEFI Spec. 2384 // 2385 WinCertUefiGuid = (WIN_CERTIFICATE_UEFI_GUID *) WinCertificate; 2386 if (WinCertUefiGuid->Hdr.dwLength <= OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData)) { 2387 break; 2388 } 2389 if (!CompareGuid (&WinCertUefiGuid->CertType, &gEfiCertPkcs7Guid)) { 2390 continue; 2391 } 2392 AuthData = WinCertUefiGuid->CertData; 2393 AuthDataSize = WinCertUefiGuid->Hdr.dwLength - OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData); 2394 } else { 2395 if (WinCertificate->dwLength < sizeof (WIN_CERTIFICATE)) { 2396 break; 2397 } 2398 continue; 2399 } 2400 2401 Status = HashPeImageByType (AuthData, AuthDataSize); 2402 if (EFI_ERROR (Status)) { 2403 continue; 2404 } 2405 2406 // 2407 // Check the digital signature against the revoked certificate in forbidden database (dbx). 2408 // 2409 if (IsForbiddenByDbx (AuthData, AuthDataSize, FALSE, NULL, NULL)) { 2410 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED; 2411 VerifyStatus = EFI_ACCESS_DENIED; 2412 break; 2413 } 2414 2415 // 2416 // Check the digital signature against the valid certificate in allowed database (db). 2417 // 2418 if (EFI_ERROR (VerifyStatus)) { 2419 if (IsAllowedByDb (AuthData, AuthDataSize, FALSE, NULL, NULL)) { 2420 VerifyStatus = EFI_SUCCESS; 2421 } 2422 } 2423 2424 // 2425 // Check the image's hash value. 2426 // 2427 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) { 2428 Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND; 2429 VerifyStatus = EFI_ACCESS_DENIED; 2430 break; 2431 } else if (EFI_ERROR (VerifyStatus)) { 2432 if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) { 2433 VerifyStatus = EFI_SUCCESS; 2434 } 2435 } 2436 } 2437 2438 if (OffSet != (SecDataDir->VirtualAddress + SecDataDir->Size)) { 2439 // 2440 // The Size in Certificate Table or the attribute certicate table is corrupted. 2441 // 2442 VerifyStatus = EFI_ACCESS_DENIED; 2443 } 2444 2445 if (!EFI_ERROR (VerifyStatus)) { 2446 return EFI_SUCCESS; 2447 } else { 2448 Status = EFI_ACCESS_DENIED; 2449 if (Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED || Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND) { 2450 // 2451 // Get image hash value as executable's signature. 2452 // 2453 SignatureListSize = sizeof (EFI_SIGNATURE_LIST) + sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize; 2454 SignatureList = (EFI_SIGNATURE_LIST *) AllocateZeroPool (SignatureListSize); 2455 if (SignatureList == NULL) { 2456 Status = EFI_OUT_OF_RESOURCES; 2457 goto Done; 2458 } 2459 SignatureList->SignatureHeaderSize = 0; 2460 SignatureList->SignatureListSize = (UINT32) SignatureListSize; 2461 SignatureList->SignatureSize = (UINT32) (sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize); 2462 CopyMem (&SignatureList->SignatureType, &mCertType, sizeof (EFI_GUID)); 2463 Signature = (EFI_SIGNATURE_DATA *) ((UINT8 *) SignatureList + sizeof (EFI_SIGNATURE_LIST)); 2464 CopyMem (Signature->SignatureData, mImageDigest, mImageDigestSize); 2465 } 2466 } 2467 2468Done: 2469 if (Status != EFI_SUCCESS) { 2470 // 2471 // Policy decides to defer or reject the image; add its information in image executable information table. 2472 // 2473 NameStr = ConvertDevicePathToText (File, FALSE, TRUE); 2474 AddImageExeInfo (Action, NameStr, File, SignatureList, SignatureListSize); 2475 if (NameStr != NULL) { 2476 DEBUG((EFI_D_INFO, "The image doesn't pass verification: %s\n", NameStr)); 2477 FreePool(NameStr); 2478 } 2479 Status = EFI_SECURITY_VIOLATION; 2480 } 2481 2482 if (SignatureList != NULL) { 2483 FreePool (SignatureList); 2484 } 2485 2486 return Status; 2487} 2488 2489/** 2490 On Ready To Boot Services Event notification handler. 2491 2492 Add the image execution information table if it is not in system configuration table. 2493 2494 @param[in] Event Event whose notification function is being invoked 2495 @param[in] Context Pointer to the notification function's context 2496 2497**/ 2498VOID 2499EFIAPI 2500OnReadyToBoot ( 2501 IN EFI_EVENT Event, 2502 IN VOID *Context 2503 ) 2504{ 2505 EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable; 2506 UINTN ImageExeInfoTableSize; 2507 2508 EfiGetSystemConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID **) &ImageExeInfoTable); 2509 if (ImageExeInfoTable != NULL) { 2510 return; 2511 } 2512 2513 ImageExeInfoTableSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE); 2514 ImageExeInfoTable = (EFI_IMAGE_EXECUTION_INFO_TABLE *) AllocateRuntimePool (ImageExeInfoTableSize); 2515 if (ImageExeInfoTable == NULL) { 2516 return ; 2517 } 2518 2519 ImageExeInfoTable->NumberOfImages = 0; 2520 gBS->InstallConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID *) ImageExeInfoTable); 2521 2522} 2523 2524/** 2525 Register security measurement handler. 2526 2527 @param ImageHandle ImageHandle of the loaded driver. 2528 @param SystemTable Pointer to the EFI System Table. 2529 2530 @retval EFI_SUCCESS The handlers were registered successfully. 2531**/ 2532EFI_STATUS 2533EFIAPI 2534DxeImageVerificationLibConstructor ( 2535 IN EFI_HANDLE ImageHandle, 2536 IN EFI_SYSTEM_TABLE *SystemTable 2537 ) 2538{ 2539 EFI_EVENT Event; 2540 2541 // 2542 // Register the event to publish the image execution table. 2543 // 2544 EfiCreateEventReadyToBootEx ( 2545 TPL_CALLBACK, 2546 OnReadyToBoot, 2547 NULL, 2548 &Event 2549 ); 2550 2551 return RegisterSecurity2Handler ( 2552 DxeImageVerificationHandler, 2553 EFI_AUTH_OPERATION_VERIFY_IMAGE | EFI_AUTH_OPERATION_IMAGE_REQUIRED 2554 ); 2555} 2556