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- /** @file
- Implement image verification services for secure boot service
- Caution: This file requires additional review when modified.
- This library will have external input - PE/COFF image.
- This external input must be validated carefully to avoid security issue like
- buffer overflow, integer overflow.
- DxeImageVerificationLibImageRead() function will make sure the PE/COFF image content
- read is within the image buffer.
- DxeImageVerificationHandler(), HashPeImageByType(), HashPeImage() function will accept
- untrusted PE/COFF image and validate its data structure within this image buffer before use.
- Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved.<BR>
- (C) Copyright 2016 Hewlett Packard Enterprise Development LP<BR>
- SPDX-License-Identifier: BSD-2-Clause-Patent
- **/
- #include "DxeImageVerificationLib.h"
- //
- // Caution: This is used by a function which may receive untrusted input.
- // These global variables hold PE/COFF image data, and they should be validated before use.
- //
- EFI_IMAGE_OPTIONAL_HEADER_PTR_UNION mNtHeader;
- UINT32 mPeCoffHeaderOffset;
- EFI_GUID mCertType;
- //
- // Information on current PE/COFF image
- //
- UINTN mImageSize;
- UINT8 *mImageBase = NULL;
- UINT8 mImageDigest[MAX_DIGEST_SIZE];
- UINTN mImageDigestSize;
- //
- // Notify string for authorization UI.
- //
- CHAR16 mNotifyString1[MAX_NOTIFY_STRING_LEN] = L"Image verification pass but not found in authorized database!";
- CHAR16 mNotifyString2[MAX_NOTIFY_STRING_LEN] = L"Launch this image anyway? (Yes/Defer/No)";
- //
- // Public Exponent of RSA Key.
- //
- CONST UINT8 mRsaE[] = { 0x01, 0x00, 0x01 };
- //
- // OID ASN.1 Value for Hash Algorithms
- //
- UINT8 mHashOidValue[] = {
- 0x2B, 0x0E, 0x03, 0x02, 0x1A, // OBJ_sha1
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04, // OBJ_sha224
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, // OBJ_sha256
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, // OBJ_sha384
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, // OBJ_sha512
- };
- HASH_TABLE mHash[] = {
- { L"SHA1", 20, &mHashOidValue[0], 5, Sha1GetContextSize, Sha1Init, Sha1Update, Sha1Final },
- { L"SHA224", 28, &mHashOidValue[5], 9, NULL, NULL, NULL, NULL },
- { L"SHA256", 32, &mHashOidValue[14], 9, Sha256GetContextSize, Sha256Init, Sha256Update, Sha256Final},
- { L"SHA384", 48, &mHashOidValue[23], 9, Sha384GetContextSize, Sha384Init, Sha384Update, Sha384Final},
- { L"SHA512", 64, &mHashOidValue[32], 9, Sha512GetContextSize, Sha512Init, Sha512Update, Sha512Final}
- };
- EFI_STRING mHashTypeStr;
- /**
- SecureBoot Hook for processing image verification.
- @param[in] VariableName Name of Variable to be found.
- @param[in] VendorGuid Variable vendor GUID.
- @param[in] DataSize Size of Data found. If size is less than the
- data, this value contains the required size.
- @param[in] Data Data pointer.
- **/
- VOID
- EFIAPI
- SecureBootHook (
- IN CHAR16 *VariableName,
- IN EFI_GUID *VendorGuid,
- IN UINTN DataSize,
- IN VOID *Data
- );
- /**
- Reads contents of a PE/COFF image in memory buffer.
- Caution: This function may receive untrusted input.
- PE/COFF image is external input, so this function will make sure the PE/COFF image content
- read is within the image buffer.
- @param FileHandle Pointer to the file handle to read the PE/COFF image.
- @param FileOffset Offset into the PE/COFF image to begin the read operation.
- @param ReadSize On input, the size in bytes of the requested read operation.
- On output, the number of bytes actually read.
- @param Buffer Output buffer that contains the data read from the PE/COFF image.
- @retval EFI_SUCCESS The specified portion of the PE/COFF image was read and the size
- **/
- EFI_STATUS
- EFIAPI
- DxeImageVerificationLibImageRead (
- IN VOID *FileHandle,
- IN UINTN FileOffset,
- IN OUT UINTN *ReadSize,
- OUT VOID *Buffer
- )
- {
- UINTN EndPosition;
- if (FileHandle == NULL || ReadSize == NULL || Buffer == NULL) {
- return EFI_INVALID_PARAMETER;
- }
- if (MAX_ADDRESS - FileOffset < *ReadSize) {
- return EFI_INVALID_PARAMETER;
- }
- EndPosition = FileOffset + *ReadSize;
- if (EndPosition > mImageSize) {
- *ReadSize = (UINT32)(mImageSize - FileOffset);
- }
- if (FileOffset >= mImageSize) {
- *ReadSize = 0;
- }
- CopyMem (Buffer, (UINT8 *)((UINTN) FileHandle + FileOffset), *ReadSize);
- return EFI_SUCCESS;
- }
- /**
- Get the image type.
- @param[in] File This is a pointer to the device path of the file that is
- being dispatched.
- @return UINT32 Image Type
- **/
- UINT32
- GetImageType (
- IN CONST EFI_DEVICE_PATH_PROTOCOL *File
- )
- {
- EFI_STATUS Status;
- EFI_HANDLE DeviceHandle;
- EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;
- EFI_BLOCK_IO_PROTOCOL *BlockIo;
- if (File == NULL) {
- return IMAGE_UNKNOWN;
- }
- //
- // First check to see if File is from a Firmware Volume
- //
- DeviceHandle = NULL;
- TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *) File;
- Status = gBS->LocateDevicePath (
- &gEfiFirmwareVolume2ProtocolGuid,
- &TempDevicePath,
- &DeviceHandle
- );
- if (!EFI_ERROR (Status)) {
- Status = gBS->OpenProtocol (
- DeviceHandle,
- &gEfiFirmwareVolume2ProtocolGuid,
- NULL,
- NULL,
- NULL,
- EFI_OPEN_PROTOCOL_TEST_PROTOCOL
- );
- if (!EFI_ERROR (Status)) {
- return IMAGE_FROM_FV;
- }
- }
- //
- // Next check to see if File is from a Block I/O device
- //
- DeviceHandle = NULL;
- TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *) File;
- Status = gBS->LocateDevicePath (
- &gEfiBlockIoProtocolGuid,
- &TempDevicePath,
- &DeviceHandle
- );
- if (!EFI_ERROR (Status)) {
- BlockIo = NULL;
- Status = gBS->OpenProtocol (
- DeviceHandle,
- &gEfiBlockIoProtocolGuid,
- (VOID **) &BlockIo,
- NULL,
- NULL,
- EFI_OPEN_PROTOCOL_GET_PROTOCOL
- );
- if (!EFI_ERROR (Status) && BlockIo != NULL) {
- if (BlockIo->Media != NULL) {
- if (BlockIo->Media->RemovableMedia) {
- //
- // Block I/O is present and specifies the media is removable
- //
- return IMAGE_FROM_REMOVABLE_MEDIA;
- } else {
- //
- // Block I/O is present and specifies the media is not removable
- //
- return IMAGE_FROM_FIXED_MEDIA;
- }
- }
- }
- }
- //
- // File is not in a Firmware Volume or on a Block I/O device, so check to see if
- // the device path supports the Simple File System Protocol.
- //
- DeviceHandle = NULL;
- TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *) File;
- Status = gBS->LocateDevicePath (
- &gEfiSimpleFileSystemProtocolGuid,
- &TempDevicePath,
- &DeviceHandle
- );
- if (!EFI_ERROR (Status)) {
- //
- // Simple File System is present without Block I/O, so assume media is fixed.
- //
- return IMAGE_FROM_FIXED_MEDIA;
- }
- //
- // File is not from an FV, Block I/O or Simple File System, so the only options
- // left are a PCI Option ROM and a Load File Protocol such as a PXE Boot from a NIC.
- //
- TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *) File;
- while (!IsDevicePathEndType (TempDevicePath)) {
- switch (DevicePathType (TempDevicePath)) {
- case MEDIA_DEVICE_PATH:
- if (DevicePathSubType (TempDevicePath) == MEDIA_RELATIVE_OFFSET_RANGE_DP) {
- return IMAGE_FROM_OPTION_ROM;
- }
- break;
- case MESSAGING_DEVICE_PATH:
- if (DevicePathSubType(TempDevicePath) == MSG_MAC_ADDR_DP) {
- return IMAGE_FROM_REMOVABLE_MEDIA;
- }
- break;
- default:
- break;
- }
- TempDevicePath = NextDevicePathNode (TempDevicePath);
- }
- return IMAGE_UNKNOWN;
- }
- /**
- Calculate hash of Pe/Coff image based on the authenticode image hashing in
- PE/COFF Specification 8.0 Appendix A
- Caution: This function may receive untrusted input.
- PE/COFF image is external input, so this function will validate its data structure
- within this image buffer before use.
- Notes: PE/COFF image has been checked by BasePeCoffLib PeCoffLoaderGetImageInfo() in
- its caller function DxeImageVerificationHandler().
- @param[in] HashAlg Hash algorithm type.
- @retval TRUE Successfully hash image.
- @retval FALSE Fail in hash image.
- **/
- BOOLEAN
- HashPeImage (
- IN UINT32 HashAlg
- )
- {
- BOOLEAN Status;
- EFI_IMAGE_SECTION_HEADER *Section;
- VOID *HashCtx;
- UINTN CtxSize;
- UINT8 *HashBase;
- UINTN HashSize;
- UINTN SumOfBytesHashed;
- EFI_IMAGE_SECTION_HEADER *SectionHeader;
- UINTN Index;
- UINTN Pos;
- UINT32 CertSize;
- UINT32 NumberOfRvaAndSizes;
- HashCtx = NULL;
- SectionHeader = NULL;
- Status = FALSE;
- if ((HashAlg >= HASHALG_MAX)) {
- return FALSE;
- }
- //
- // Initialize context of hash.
- //
- ZeroMem (mImageDigest, MAX_DIGEST_SIZE);
- switch (HashAlg) {
- case HASHALG_SHA1:
- mImageDigestSize = SHA1_DIGEST_SIZE;
- mCertType = gEfiCertSha1Guid;
- break;
- case HASHALG_SHA256:
- mImageDigestSize = SHA256_DIGEST_SIZE;
- mCertType = gEfiCertSha256Guid;
- break;
- case HASHALG_SHA384:
- mImageDigestSize = SHA384_DIGEST_SIZE;
- mCertType = gEfiCertSha384Guid;
- break;
- case HASHALG_SHA512:
- mImageDigestSize = SHA512_DIGEST_SIZE;
- mCertType = gEfiCertSha512Guid;
- break;
- default:
- return FALSE;
- }
- mHashTypeStr = mHash[HashAlg].Name;
- CtxSize = mHash[HashAlg].GetContextSize();
- HashCtx = AllocatePool (CtxSize);
- if (HashCtx == NULL) {
- return FALSE;
- }
- // 1. Load the image header into memory.
- // 2. Initialize a SHA hash context.
- Status = mHash[HashAlg].HashInit(HashCtx);
- if (!Status) {
- goto Done;
- }
- //
- // Measuring PE/COFF Image Header;
- // But CheckSum field and SECURITY data directory (certificate) are excluded
- //
- //
- // 3. Calculate the distance from the base of the image header to the image checksum address.
- // 4. Hash the image header from its base to beginning of the image checksum.
- //
- HashBase = mImageBase;
- if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
- //
- // Use PE32 offset.
- //
- HashSize = (UINTN) (&mNtHeader.Pe32->OptionalHeader.CheckSum) - (UINTN) HashBase;
- NumberOfRvaAndSizes = mNtHeader.Pe32->OptionalHeader.NumberOfRvaAndSizes;
- } else if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
- //
- // Use PE32+ offset.
- //
- HashSize = (UINTN) (&mNtHeader.Pe32Plus->OptionalHeader.CheckSum) - (UINTN) HashBase;
- NumberOfRvaAndSizes = mNtHeader.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes;
- } else {
- //
- // Invalid header magic number.
- //
- Status = FALSE;
- goto Done;
- }
- Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
- if (!Status) {
- goto Done;
- }
- //
- // 5. Skip over the image checksum (it occupies a single ULONG).
- //
- if (NumberOfRvaAndSizes <= EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
- //
- // 6. Since there is no Cert Directory in optional header, hash everything
- // from the end of the checksum to the end of image header.
- //
- if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
- //
- // Use PE32 offset.
- //
- HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.CheckSum + sizeof (UINT32);
- HashSize = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders - ((UINTN) HashBase - (UINTN) mImageBase);
- } else {
- //
- // Use PE32+ offset.
- //
- HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32);
- HashSize = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders - ((UINTN) HashBase - (UINTN) mImageBase);
- }
- if (HashSize != 0) {
- Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
- if (!Status) {
- goto Done;
- }
- }
- } else {
- //
- // 7. Hash everything from the end of the checksum to the start of the Cert Directory.
- //
- if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
- //
- // Use PE32 offset.
- //
- HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.CheckSum + sizeof (UINT32);
- HashSize = (UINTN) (&mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;
- } else {
- //
- // Use PE32+ offset.
- //
- HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32);
- HashSize = (UINTN) (&mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;
- }
- if (HashSize != 0) {
- Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
- if (!Status) {
- goto Done;
- }
- }
- //
- // 8. Skip over the Cert Directory. (It is sizeof(IMAGE_DATA_DIRECTORY) bytes.)
- // 9. Hash everything from the end of the Cert Directory to the end of image header.
- //
- if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
- //
- // Use PE32 offset
- //
- HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1];
- HashSize = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders - ((UINTN) HashBase - (UINTN) mImageBase);
- } else {
- //
- // Use PE32+ offset.
- //
- HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1];
- HashSize = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders - ((UINTN) HashBase - (UINTN) mImageBase);
- }
- if (HashSize != 0) {
- Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
- if (!Status) {
- goto Done;
- }
- }
- }
- //
- // 10. Set the SUM_OF_BYTES_HASHED to the size of the header.
- //
- if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
- //
- // Use PE32 offset.
- //
- SumOfBytesHashed = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders;
- } else {
- //
- // Use PE32+ offset
- //
- SumOfBytesHashed = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders;
- }
- Section = (EFI_IMAGE_SECTION_HEADER *) (
- mImageBase +
- mPeCoffHeaderOffset +
- sizeof (UINT32) +
- sizeof (EFI_IMAGE_FILE_HEADER) +
- mNtHeader.Pe32->FileHeader.SizeOfOptionalHeader
- );
- //
- // 11. Build a temporary table of pointers to all the IMAGE_SECTION_HEADER
- // structures in the image. The 'NumberOfSections' field of the image
- // header indicates how big the table should be. Do not include any
- // IMAGE_SECTION_HEADERs in the table whose 'SizeOfRawData' field is zero.
- //
- SectionHeader = (EFI_IMAGE_SECTION_HEADER *) AllocateZeroPool (sizeof (EFI_IMAGE_SECTION_HEADER) * mNtHeader.Pe32->FileHeader.NumberOfSections);
- if (SectionHeader == NULL) {
- Status = FALSE;
- goto Done;
- }
- //
- // 12. Using the 'PointerToRawData' in the referenced section headers as
- // a key, arrange the elements in the table in ascending order. In other
- // words, sort the section headers according to the disk-file offset of
- // the section.
- //
- for (Index = 0; Index < mNtHeader.Pe32->FileHeader.NumberOfSections; Index++) {
- Pos = Index;
- while ((Pos > 0) && (Section->PointerToRawData < SectionHeader[Pos - 1].PointerToRawData)) {
- CopyMem (&SectionHeader[Pos], &SectionHeader[Pos - 1], sizeof (EFI_IMAGE_SECTION_HEADER));
- Pos--;
- }
- CopyMem (&SectionHeader[Pos], Section, sizeof (EFI_IMAGE_SECTION_HEADER));
- Section += 1;
- }
- //
- // 13. Walk through the sorted table, bring the corresponding section
- // into memory, and hash the entire section (using the 'SizeOfRawData'
- // field in the section header to determine the amount of data to hash).
- // 14. Add the section's 'SizeOfRawData' to SUM_OF_BYTES_HASHED .
- // 15. Repeat steps 13 and 14 for all the sections in the sorted table.
- //
- for (Index = 0; Index < mNtHeader.Pe32->FileHeader.NumberOfSections; Index++) {
- Section = &SectionHeader[Index];
- if (Section->SizeOfRawData == 0) {
- continue;
- }
- HashBase = mImageBase + Section->PointerToRawData;
- HashSize = (UINTN) Section->SizeOfRawData;
- Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
- if (!Status) {
- goto Done;
- }
- SumOfBytesHashed += HashSize;
- }
- //
- // 16. If the file size is greater than SUM_OF_BYTES_HASHED, there is extra
- // data in the file that needs to be added to the hash. This data begins
- // at file offset SUM_OF_BYTES_HASHED and its length is:
- // FileSize - (CertDirectory->Size)
- //
- if (mImageSize > SumOfBytesHashed) {
- HashBase = mImageBase + SumOfBytesHashed;
- if (NumberOfRvaAndSizes <= EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
- CertSize = 0;
- } else {
- if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
- //
- // Use PE32 offset.
- //
- CertSize = mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY].Size;
- } else {
- //
- // Use PE32+ offset.
- //
- CertSize = mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY].Size;
- }
- }
- if (mImageSize > CertSize + SumOfBytesHashed) {
- HashSize = (UINTN) (mImageSize - CertSize - SumOfBytesHashed);
- Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
- if (!Status) {
- goto Done;
- }
- } else if (mImageSize < CertSize + SumOfBytesHashed) {
- Status = FALSE;
- goto Done;
- }
- }
- Status = mHash[HashAlg].HashFinal(HashCtx, mImageDigest);
- Done:
- if (HashCtx != NULL) {
- FreePool (HashCtx);
- }
- if (SectionHeader != NULL) {
- FreePool (SectionHeader);
- }
- return Status;
- }
- /**
- Recognize the Hash algorithm in PE/COFF Authenticode and calculate hash of
- Pe/Coff image based on the authenticode image hashing in PE/COFF Specification
- 8.0 Appendix A
- Caution: This function may receive untrusted input.
- PE/COFF image is external input, so this function will validate its data structure
- within this image buffer before use.
- @param[in] AuthData Pointer to the Authenticode Signature retrieved from signed image.
- @param[in] AuthDataSize Size of the Authenticode Signature in bytes.
- @retval EFI_UNSUPPORTED Hash algorithm is not supported.
- @retval EFI_SUCCESS Hash successfully.
- **/
- EFI_STATUS
- HashPeImageByType (
- IN UINT8 *AuthData,
- IN UINTN AuthDataSize
- )
- {
- UINT8 Index;
- for (Index = 0; Index < HASHALG_MAX; Index++) {
- //
- // Check the Hash algorithm in PE/COFF Authenticode.
- // According to PKCS#7 Definition:
- // SignedData ::= SEQUENCE {
- // version Version,
- // digestAlgorithms DigestAlgorithmIdentifiers,
- // contentInfo ContentInfo,
- // .... }
- // The DigestAlgorithmIdentifiers can be used to determine the hash algorithm in PE/COFF hashing
- // This field has the fixed offset (+32) in final Authenticode ASN.1 data.
- // Fixed offset (+32) is calculated based on two bytes of length encoding.
- //
- if ((*(AuthData + 1) & TWO_BYTE_ENCODE) != TWO_BYTE_ENCODE) {
- //
- // Only support two bytes of Long Form of Length Encoding.
- //
- continue;
- }
- if (AuthDataSize < 32 + mHash[Index].OidLength) {
- return EFI_UNSUPPORTED;
- }
- if (CompareMem (AuthData + 32, mHash[Index].OidValue, mHash[Index].OidLength) == 0) {
- break;
- }
- }
- if (Index == HASHALG_MAX) {
- return EFI_UNSUPPORTED;
- }
- //
- // HASH PE Image based on Hash algorithm in PE/COFF Authenticode.
- //
- if (!HashPeImage(Index)) {
- return EFI_UNSUPPORTED;
- }
- return EFI_SUCCESS;
- }
- /**
- Returns the size of a given image execution info table in bytes.
- This function returns the size, in bytes, of the image execution info table specified by
- ImageExeInfoTable. If ImageExeInfoTable is NULL, then 0 is returned.
- @param ImageExeInfoTable A pointer to a image execution info table structure.
- @retval 0 If ImageExeInfoTable is NULL.
- @retval Others The size of a image execution info table in bytes.
- **/
- UINTN
- GetImageExeInfoTableSize (
- EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable
- )
- {
- UINTN Index;
- EFI_IMAGE_EXECUTION_INFO *ImageExeInfoItem;
- UINTN TotalSize;
- if (ImageExeInfoTable == NULL) {
- return 0;
- }
- ImageExeInfoItem = (EFI_IMAGE_EXECUTION_INFO *) ((UINT8 *) ImageExeInfoTable + sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE));
- TotalSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE);
- for (Index = 0; Index < ImageExeInfoTable->NumberOfImages; Index++) {
- TotalSize += ReadUnaligned32 ((UINT32 *) &ImageExeInfoItem->InfoSize);
- ImageExeInfoItem = (EFI_IMAGE_EXECUTION_INFO *) ((UINT8 *) ImageExeInfoItem + ReadUnaligned32 ((UINT32 *) &ImageExeInfoItem->InfoSize));
- }
- return TotalSize;
- }
- /**
- Create an Image Execution Information Table entry and add it to system configuration table.
- @param[in] Action Describes the action taken by the firmware regarding this image.
- @param[in] Name Input a null-terminated, user-friendly name.
- @param[in] DevicePath Input device path pointer.
- @param[in] Signature Input signature info in EFI_SIGNATURE_LIST data structure.
- @param[in] SignatureSize Size of signature.
- **/
- VOID
- AddImageExeInfo (
- IN EFI_IMAGE_EXECUTION_ACTION Action,
- IN CHAR16 *Name OPTIONAL,
- IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
- IN EFI_SIGNATURE_LIST *Signature OPTIONAL,
- IN UINTN SignatureSize
- )
- {
- EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable;
- EFI_IMAGE_EXECUTION_INFO_TABLE *NewImageExeInfoTable;
- EFI_IMAGE_EXECUTION_INFO *ImageExeInfoEntry;
- UINTN ImageExeInfoTableSize;
- UINTN NewImageExeInfoEntrySize;
- UINTN NameStringLen;
- UINTN DevicePathSize;
- CHAR16 *NameStr;
- ImageExeInfoTable = NULL;
- NewImageExeInfoTable = NULL;
- ImageExeInfoEntry = NULL;
- NameStringLen = 0;
- NameStr = NULL;
- if (DevicePath == NULL) {
- return ;
- }
- if (Name != NULL) {
- NameStringLen = StrSize (Name);
- } else {
- NameStringLen = sizeof (CHAR16);
- }
- EfiGetSystemConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID **) &ImageExeInfoTable);
- if (ImageExeInfoTable != NULL) {
- //
- // The table has been found!
- // We must enlarge the table to accomodate the new exe info entry.
- //
- ImageExeInfoTableSize = GetImageExeInfoTableSize (ImageExeInfoTable);
- } else {
- //
- // Not Found!
- // We should create a new table to append to the configuration table.
- //
- ImageExeInfoTableSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE);
- }
- DevicePathSize = GetDevicePathSize (DevicePath);
- //
- // Signature size can be odd. Pad after signature to ensure next EXECUTION_INFO entry align
- //
- NewImageExeInfoEntrySize = sizeof (EFI_IMAGE_EXECUTION_INFO) + NameStringLen + DevicePathSize + SignatureSize;
- NewImageExeInfoTable = (EFI_IMAGE_EXECUTION_INFO_TABLE *) AllocateRuntimePool (ImageExeInfoTableSize + NewImageExeInfoEntrySize);
- if (NewImageExeInfoTable == NULL) {
- return ;
- }
- if (ImageExeInfoTable != NULL) {
- CopyMem (NewImageExeInfoTable, ImageExeInfoTable, ImageExeInfoTableSize);
- } else {
- NewImageExeInfoTable->NumberOfImages = 0;
- }
- NewImageExeInfoTable->NumberOfImages++;
- ImageExeInfoEntry = (EFI_IMAGE_EXECUTION_INFO *) ((UINT8 *) NewImageExeInfoTable + ImageExeInfoTableSize);
- //
- // Update new item's information.
- //
- WriteUnaligned32 ((UINT32 *) ImageExeInfoEntry, Action);
- WriteUnaligned32 ((UINT32 *) ((UINT8 *) ImageExeInfoEntry + sizeof (EFI_IMAGE_EXECUTION_ACTION)), (UINT32) NewImageExeInfoEntrySize);
- NameStr = (CHAR16 *)(ImageExeInfoEntry + 1);
- if (Name != NULL) {
- CopyMem ((UINT8 *) NameStr, Name, NameStringLen);
- } else {
- ZeroMem ((UINT8 *) NameStr, sizeof (CHAR16));
- }
- CopyMem (
- (UINT8 *) NameStr + NameStringLen,
- DevicePath,
- DevicePathSize
- );
- if (Signature != NULL) {
- CopyMem (
- (UINT8 *) NameStr + NameStringLen + DevicePathSize,
- Signature,
- SignatureSize
- );
- }
- //
- // Update/replace the image execution table.
- //
- gBS->InstallConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID *) NewImageExeInfoTable);
- //
- // Free Old table data!
- //
- if (ImageExeInfoTable != NULL) {
- FreePool (ImageExeInfoTable);
- }
- }
- /**
- Check whether the hash of an given X.509 certificate is in forbidden database (DBX).
- @param[in] Certificate Pointer to X.509 Certificate that is searched for.
- @param[in] CertSize Size of X.509 Certificate.
- @param[in] SignatureList Pointer to the Signature List in forbidden database.
- @param[in] SignatureListSize Size of Signature List.
- @param[out] RevocationTime Return the time that the certificate was revoked.
- @return TRUE The certificate hash is found in the forbidden database.
- @return FALSE The certificate hash is not found in the forbidden database.
- **/
- BOOLEAN
- IsCertHashFoundInDatabase (
- IN UINT8 *Certificate,
- IN UINTN CertSize,
- IN EFI_SIGNATURE_LIST *SignatureList,
- IN UINTN SignatureListSize,
- OUT EFI_TIME *RevocationTime
- )
- {
- BOOLEAN IsFound;
- BOOLEAN Status;
- EFI_SIGNATURE_LIST *DbxList;
- UINTN DbxSize;
- EFI_SIGNATURE_DATA *CertHash;
- UINTN CertHashCount;
- UINTN Index;
- UINT32 HashAlg;
- VOID *HashCtx;
- UINT8 CertDigest[MAX_DIGEST_SIZE];
- UINT8 *DbxCertHash;
- UINTN SiglistHeaderSize;
- UINT8 *TBSCert;
- UINTN TBSCertSize;
- IsFound = FALSE;
- DbxList = SignatureList;
- DbxSize = SignatureListSize;
- HashCtx = NULL;
- HashAlg = HASHALG_MAX;
- if ((RevocationTime == NULL) || (DbxList == NULL)) {
- return FALSE;
- }
- //
- // Retrieve the TBSCertificate from the X.509 Certificate.
- //
- if (!X509GetTBSCert (Certificate, CertSize, &TBSCert, &TBSCertSize)) {
- return FALSE;
- }
- while ((DbxSize > 0) && (SignatureListSize >= DbxList->SignatureListSize)) {
- //
- // Determine Hash Algorithm of Certificate in the forbidden database.
- //
- if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha256Guid)) {
- HashAlg = HASHALG_SHA256;
- } else if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha384Guid)) {
- HashAlg = HASHALG_SHA384;
- } else if (CompareGuid (&DbxList->SignatureType, &gEfiCertX509Sha512Guid)) {
- HashAlg = HASHALG_SHA512;
- } else {
- DbxSize -= DbxList->SignatureListSize;
- DbxList = (EFI_SIGNATURE_LIST *) ((UINT8 *) DbxList + DbxList->SignatureListSize);
- continue;
- }
- //
- // Calculate the hash value of current TBSCertificate for comparision.
- //
- if (mHash[HashAlg].GetContextSize == NULL) {
- goto Done;
- }
- ZeroMem (CertDigest, MAX_DIGEST_SIZE);
- HashCtx = AllocatePool (mHash[HashAlg].GetContextSize ());
- if (HashCtx == NULL) {
- goto Done;
- }
- Status = mHash[HashAlg].HashInit (HashCtx);
- if (!Status) {
- goto Done;
- }
- Status = mHash[HashAlg].HashUpdate (HashCtx, TBSCert, TBSCertSize);
- if (!Status) {
- goto Done;
- }
- Status = mHash[HashAlg].HashFinal (HashCtx, CertDigest);
- if (!Status) {
- goto Done;
- }
- SiglistHeaderSize = sizeof (EFI_SIGNATURE_LIST) + DbxList->SignatureHeaderSize;
- CertHash = (EFI_SIGNATURE_DATA *) ((UINT8 *) DbxList + SiglistHeaderSize);
- CertHashCount = (DbxList->SignatureListSize - SiglistHeaderSize) / DbxList->SignatureSize;
- for (Index = 0; Index < CertHashCount; Index++) {
- //
- // Iterate each Signature Data Node within this CertList for verify.
- //
- DbxCertHash = CertHash->SignatureData;
- if (CompareMem (DbxCertHash, CertDigest, mHash[HashAlg].DigestLength) == 0) {
- //
- // Hash of Certificate is found in forbidden database.
- //
- IsFound = TRUE;
- //
- // Return the revocation time.
- //
- CopyMem (RevocationTime, (EFI_TIME *)(DbxCertHash + mHash[HashAlg].DigestLength), sizeof (EFI_TIME));
- goto Done;
- }
- CertHash = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertHash + DbxList->SignatureSize);
- }
- DbxSize -= DbxList->SignatureListSize;
- DbxList = (EFI_SIGNATURE_LIST *) ((UINT8 *) DbxList + DbxList->SignatureListSize);
- }
- Done:
- if (HashCtx != NULL) {
- FreePool (HashCtx);
- }
- return IsFound;
- }
- /**
- Check whether signature is in specified database.
- @param[in] VariableName Name of database variable that is searched in.
- @param[in] Signature Pointer to signature that is searched for.
- @param[in] CertType Pointer to hash algrithom.
- @param[in] SignatureSize Size of Signature.
- @return TRUE Found the signature in the variable database.
- @return FALSE Not found the signature in the variable database.
- **/
- BOOLEAN
- IsSignatureFoundInDatabase (
- IN CHAR16 *VariableName,
- IN UINT8 *Signature,
- IN EFI_GUID *CertType,
- IN UINTN SignatureSize
- )
- {
- EFI_STATUS Status;
- EFI_SIGNATURE_LIST *CertList;
- EFI_SIGNATURE_DATA *Cert;
- UINTN DataSize;
- UINT8 *Data;
- UINTN Index;
- UINTN CertCount;
- BOOLEAN IsFound;
- //
- // Read signature database variable.
- //
- IsFound = FALSE;
- Data = NULL;
- DataSize = 0;
- Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
- if (Status != EFI_BUFFER_TOO_SMALL) {
- return FALSE;
- }
- Data = (UINT8 *) AllocateZeroPool (DataSize);
- if (Data == NULL) {
- return FALSE;
- }
- Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, Data);
- if (EFI_ERROR (Status)) {
- goto Done;
- }
- //
- // Enumerate all signature data in SigDB to check if executable's signature exists.
- //
- CertList = (EFI_SIGNATURE_LIST *) Data;
- while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
- CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
- Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
- if ((CertList->SignatureSize == sizeof(EFI_SIGNATURE_DATA) - 1 + SignatureSize) && (CompareGuid(&CertList->SignatureType, CertType))) {
- for (Index = 0; Index < CertCount; Index++) {
- if (CompareMem (Cert->SignatureData, Signature, SignatureSize) == 0) {
- //
- // Find the signature in database.
- //
- IsFound = TRUE;
- //
- // Entries in UEFI_IMAGE_SECURITY_DATABASE that are used to validate image should be measured
- //
- if (StrCmp(VariableName, EFI_IMAGE_SECURITY_DATABASE) == 0) {
- SecureBootHook (VariableName, &gEfiImageSecurityDatabaseGuid, CertList->SignatureSize, Cert);
- }
- break;
- }
- Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
- }
- if (IsFound) {
- break;
- }
- }
- DataSize -= CertList->SignatureListSize;
- CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
- }
- Done:
- if (Data != NULL) {
- FreePool (Data);
- }
- return IsFound;
- }
- /**
- Check whether the timestamp is valid by comparing the signing time and the revocation time.
- @param SigningTime A pointer to the signing time.
- @param RevocationTime A pointer to the revocation time.
- @retval TRUE The SigningTime is not later than the RevocationTime.
- @retval FALSE The SigningTime is later than the RevocationTime.
- **/
- BOOLEAN
- IsValidSignatureByTimestamp (
- IN EFI_TIME *SigningTime,
- IN EFI_TIME *RevocationTime
- )
- {
- if (SigningTime->Year != RevocationTime->Year) {
- return (BOOLEAN) (SigningTime->Year < RevocationTime->Year);
- } else if (SigningTime->Month != RevocationTime->Month) {
- return (BOOLEAN) (SigningTime->Month < RevocationTime->Month);
- } else if (SigningTime->Day != RevocationTime->Day) {
- return (BOOLEAN) (SigningTime->Day < RevocationTime->Day);
- } else if (SigningTime->Hour != RevocationTime->Hour) {
- return (BOOLEAN) (SigningTime->Hour < RevocationTime->Hour);
- } else if (SigningTime->Minute != RevocationTime->Minute) {
- return (BOOLEAN) (SigningTime->Minute < RevocationTime->Minute);
- }
- return (BOOLEAN) (SigningTime->Second <= RevocationTime->Second);
- }
- /**
- Check if the given time value is zero.
- @param[in] Time Pointer of a time value.
- @retval TRUE The Time is Zero.
- @retval FALSE The Time is not Zero.
- **/
- BOOLEAN
- IsTimeZero (
- IN EFI_TIME *Time
- )
- {
- if ((Time->Year == 0) && (Time->Month == 0) && (Time->Day == 0) &&
- (Time->Hour == 0) && (Time->Minute == 0) && (Time->Second == 0)) {
- return TRUE;
- }
- return FALSE;
- }
- /**
- Check whether the timestamp signature is valid and the signing time is also earlier than
- the revocation time.
- @param[in] AuthData Pointer to the Authenticode signature retrieved from signed image.
- @param[in] AuthDataSize Size of the Authenticode signature in bytes.
- @param[in] RevocationTime The time that the certificate was revoked.
- @retval TRUE Timestamp signature is valid and signing time is no later than the
- revocation time.
- @retval FALSE Timestamp signature is not valid or the signing time is later than the
- revocation time.
- **/
- BOOLEAN
- PassTimestampCheck (
- IN UINT8 *AuthData,
- IN UINTN AuthDataSize,
- IN EFI_TIME *RevocationTime
- )
- {
- EFI_STATUS Status;
- BOOLEAN VerifyStatus;
- EFI_SIGNATURE_LIST *CertList;
- EFI_SIGNATURE_DATA *Cert;
- UINT8 *DbtData;
- UINTN DbtDataSize;
- UINT8 *RootCert;
- UINTN RootCertSize;
- UINTN Index;
- UINTN CertCount;
- EFI_TIME SigningTime;
- //
- // Variable Initialization
- //
- VerifyStatus = FALSE;
- DbtData = NULL;
- CertList = NULL;
- Cert = NULL;
- RootCert = NULL;
- RootCertSize = 0;
- //
- // If RevocationTime is zero, the certificate shall be considered to always be revoked.
- //
- if (IsTimeZero (RevocationTime)) {
- return FALSE;
- }
- //
- // RevocationTime is non-zero, the certificate should be considered to be revoked from that time and onwards.
- // Using the dbt to get the trusted TSA certificates.
- //
- DbtDataSize = 0;
- Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE2, &gEfiImageSecurityDatabaseGuid, NULL, &DbtDataSize, NULL);
- if (Status != EFI_BUFFER_TOO_SMALL) {
- goto Done;
- }
- DbtData = (UINT8 *) AllocateZeroPool (DbtDataSize);
- if (DbtData == NULL) {
- goto Done;
- }
- Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE2, &gEfiImageSecurityDatabaseGuid, NULL, &DbtDataSize, (VOID *) DbtData);
- if (EFI_ERROR (Status)) {
- goto Done;
- }
- CertList = (EFI_SIGNATURE_LIST *) DbtData;
- while ((DbtDataSize > 0) && (DbtDataSize >= CertList->SignatureListSize)) {
- if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
- Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
- CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
- for (Index = 0; Index < CertCount; Index++) {
- //
- // Iterate each Signature Data Node within this CertList for verify.
- //
- RootCert = Cert->SignatureData;
- RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
- //
- // Get the signing time if the timestamp signature is valid.
- //
- if (ImageTimestampVerify (AuthData, AuthDataSize, RootCert, RootCertSize, &SigningTime)) {
- //
- // The signer signature is valid only when the signing time is earlier than revocation time.
- //
- if (IsValidSignatureByTimestamp (&SigningTime, RevocationTime)) {
- VerifyStatus = TRUE;
- goto Done;
- }
- }
- Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
- }
- }
- DbtDataSize -= CertList->SignatureListSize;
- CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
- }
- Done:
- if (DbtData != NULL) {
- FreePool (DbtData);
- }
- return VerifyStatus;
- }
- /**
- Check whether the image signature is forbidden by the forbidden database (dbx).
- The image is forbidden to load if any certificates for signing are revoked before signing time.
- @param[in] AuthData Pointer to the Authenticode signature retrieved from the signed image.
- @param[in] AuthDataSize Size of the Authenticode signature in bytes.
- @retval TRUE Image is forbidden by dbx.
- @retval FALSE Image is not forbidden by dbx.
- **/
- BOOLEAN
- IsForbiddenByDbx (
- IN UINT8 *AuthData,
- IN UINTN AuthDataSize
- )
- {
- EFI_STATUS Status;
- BOOLEAN IsForbidden;
- UINT8 *Data;
- UINTN DataSize;
- EFI_SIGNATURE_LIST *CertList;
- UINTN CertListSize;
- EFI_SIGNATURE_DATA *CertData;
- UINT8 *RootCert;
- UINTN RootCertSize;
- UINTN CertCount;
- UINTN Index;
- UINT8 *CertBuffer;
- UINTN BufferLength;
- UINT8 *TrustedCert;
- UINTN TrustedCertLength;
- UINT8 CertNumber;
- UINT8 *CertPtr;
- UINT8 *Cert;
- UINTN CertSize;
- EFI_TIME RevocationTime;
- //
- // Variable Initialization
- //
- IsForbidden = FALSE;
- Data = NULL;
- CertList = NULL;
- CertData = NULL;
- RootCert = NULL;
- RootCertSize = 0;
- Cert = NULL;
- CertBuffer = NULL;
- BufferLength = 0;
- TrustedCert = NULL;
- TrustedCertLength = 0;
- //
- // The image will not be forbidden if dbx can't be got.
- //
- DataSize = 0;
- Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
- if (Status != EFI_BUFFER_TOO_SMALL) {
- return IsForbidden;
- }
- Data = (UINT8 *) AllocateZeroPool (DataSize);
- if (Data == NULL) {
- return IsForbidden;
- }
- Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data);
- if (EFI_ERROR (Status)) {
- return IsForbidden;
- }
- //
- // Verify image signature with RAW X509 certificates in DBX database.
- // If passed, the image will be forbidden.
- //
- CertList = (EFI_SIGNATURE_LIST *) Data;
- CertListSize = DataSize;
- while ((CertListSize > 0) && (CertListSize >= CertList->SignatureListSize)) {
- if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
- CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
- CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
- for (Index = 0; Index < CertCount; Index++) {
- //
- // Iterate each Signature Data Node within this CertList for verify.
- //
- RootCert = CertData->SignatureData;
- RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
- //
- // Call AuthenticodeVerify library to Verify Authenticode struct.
- //
- IsForbidden = AuthenticodeVerify (
- AuthData,
- AuthDataSize,
- RootCert,
- RootCertSize,
- mImageDigest,
- mImageDigestSize
- );
- if (IsForbidden) {
- DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature is forbidden by DBX.\n"));
- goto Done;
- }
- CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize);
- }
- }
- CertListSize -= CertList->SignatureListSize;
- CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
- }
- //
- // Check X.509 Certificate Hash & Possible Timestamp.
- //
- //
- // Retrieve the certificate stack from AuthData
- // The output CertStack format will be:
- // UINT8 CertNumber;
- // UINT32 Cert1Length;
- // UINT8 Cert1[];
- // UINT32 Cert2Length;
- // UINT8 Cert2[];
- // ...
- // UINT32 CertnLength;
- // UINT8 Certn[];
- //
- Pkcs7GetSigners (AuthData, AuthDataSize, &CertBuffer, &BufferLength, &TrustedCert, &TrustedCertLength);
- if ((BufferLength == 0) || (CertBuffer == NULL)) {
- IsForbidden = TRUE;
- goto Done;
- }
- //
- // Check if any hash of certificates embedded in AuthData is in the forbidden database.
- //
- CertNumber = (UINT8) (*CertBuffer);
- CertPtr = CertBuffer + 1;
- for (Index = 0; Index < CertNumber; Index++) {
- CertSize = (UINTN) ReadUnaligned32 ((UINT32 *)CertPtr);
- Cert = (UINT8 *)CertPtr + sizeof (UINT32);
- //
- // Advance CertPtr to the next cert in image signer's cert list
- //
- CertPtr = CertPtr + sizeof (UINT32) + CertSize;
- if (IsCertHashFoundInDatabase (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data, DataSize, &RevocationTime)) {
- //
- // Check the timestamp signature and signing time to determine if the image can be trusted.
- //
- IsForbidden = TRUE;
- if (PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime)) {
- IsForbidden = FALSE;
- //
- // Pass DBT check. Continue to check other certs in image signer's cert list against DBX, DBT
- //
- continue;
- }
- DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature failed the timestamp check.\n"));
- goto Done;
- }
- }
- Done:
- if (Data != NULL) {
- FreePool (Data);
- }
- Pkcs7FreeSigners (CertBuffer);
- Pkcs7FreeSigners (TrustedCert);
- return IsForbidden;
- }
- /**
- Check whether the image signature can be verified by the trusted certificates in DB database.
- @param[in] AuthData Pointer to the Authenticode signature retrieved from signed image.
- @param[in] AuthDataSize Size of the Authenticode signature in bytes.
- @retval TRUE Image passed verification using certificate in db.
- @retval FALSE Image didn't pass verification using certificate in db.
- **/
- BOOLEAN
- IsAllowedByDb (
- IN UINT8 *AuthData,
- IN UINTN AuthDataSize
- )
- {
- EFI_STATUS Status;
- BOOLEAN VerifyStatus;
- EFI_SIGNATURE_LIST *CertList;
- EFI_SIGNATURE_DATA *CertData;
- UINTN DataSize;
- UINT8 *Data;
- UINT8 *RootCert;
- UINTN RootCertSize;
- UINTN Index;
- UINTN CertCount;
- UINTN DbxDataSize;
- UINT8 *DbxData;
- EFI_TIME RevocationTime;
- Data = NULL;
- CertList = NULL;
- CertData = NULL;
- RootCert = NULL;
- DbxData = NULL;
- RootCertSize = 0;
- VerifyStatus = FALSE;
- DataSize = 0;
- Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
- if (Status == EFI_BUFFER_TOO_SMALL) {
- Data = (UINT8 *) AllocateZeroPool (DataSize);
- if (Data == NULL) {
- return VerifyStatus;
- }
- Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data);
- if (EFI_ERROR (Status)) {
- goto Done;
- }
- //
- // Find X509 certificate in Signature List to verify the signature in pkcs7 signed data.
- //
- CertList = (EFI_SIGNATURE_LIST *) Data;
- while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
- if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
- CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
- CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
- for (Index = 0; Index < CertCount; Index++) {
- //
- // Iterate each Signature Data Node within this CertList for verify.
- //
- RootCert = CertData->SignatureData;
- RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
- //
- // Call AuthenticodeVerify library to Verify Authenticode struct.
- //
- VerifyStatus = AuthenticodeVerify (
- AuthData,
- AuthDataSize,
- RootCert,
- RootCertSize,
- mImageDigest,
- mImageDigestSize
- );
- if (VerifyStatus) {
- //
- // Here We still need to check if this RootCert's Hash is revoked
- //
- Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, NULL);
- if (Status == EFI_BUFFER_TOO_SMALL) {
- goto Done;
- }
- DbxData = (UINT8 *) AllocateZeroPool (DbxDataSize);
- if (DbxData == NULL) {
- goto Done;
- }
- Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, (VOID *) DbxData);
- if (EFI_ERROR (Status)) {
- goto Done;
- }
- if (IsCertHashFoundInDatabase (RootCert, RootCertSize, (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime)) {
- //
- // Check the timestamp signature and signing time to determine if the RootCert can be trusted.
- //
- VerifyStatus = PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime);
- if (!VerifyStatus) {
- DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed and signature is accepted by DB, but its root cert failed the timestamp check.\n"));
- }
- }
- goto Done;
- }
- CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize);
- }
- }
- DataSize -= CertList->SignatureListSize;
- CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
- }
- }
- Done:
- if (VerifyStatus) {
- SecureBootHook (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, CertList->SignatureSize, CertData);
- }
- if (Data != NULL) {
- FreePool (Data);
- }
- if (DbxData != NULL) {
- FreePool (DbxData);
- }
- return VerifyStatus;
- }
- /**
- Provide verification service for signed images, which include both signature validation
- and platform policy control. For signature types, both UEFI WIN_CERTIFICATE_UEFI_GUID and
- MSFT Authenticode type signatures are supported.
- In this implementation, only verify external executables when in USER MODE.
- Executables from FV is bypass, so pass in AuthenticationStatus is ignored.
- The image verification policy is:
- If the image is signed,
- At least one valid signature or at least one hash value of the image must match a record
- in the security database "db", and no valid signature nor any hash value of the image may
- be reflected in the security database "dbx".
- Otherwise, the image is not signed,
- The SHA256 hash value of the image must match a record in the security database "db", and
- not be reflected in the security data base "dbx".
- Caution: This function may receive untrusted input.
- PE/COFF image is external input, so this function will validate its data structure
- within this image buffer before use.
- @param[in] AuthenticationStatus
- This is the authentication status returned from the security
- measurement services for the input file.
- @param[in] File This is a pointer to the device path of the file that is
- being dispatched. This will optionally be used for logging.
- @param[in] FileBuffer File buffer matches the input file device path.
- @param[in] FileSize Size of File buffer matches the input file device path.
- @param[in] BootPolicy A boot policy that was used to call LoadImage() UEFI service.
- @retval EFI_SUCCESS The file specified by DevicePath and non-NULL
- FileBuffer did authenticate, and the platform policy dictates
- that the DXE Foundation may use the file.
- @retval EFI_SUCCESS The device path specified by NULL device path DevicePath
- and non-NULL FileBuffer did authenticate, and the platform
- policy dictates that the DXE Foundation may execute the image in
- FileBuffer.
- @retval EFI_OUT_RESOURCE Fail to allocate memory.
- @retval EFI_SECURITY_VIOLATION The file specified by File did not authenticate, and
- the platform policy dictates that File should be placed
- in the untrusted state. The image has been added to the file
- execution table.
- @retval EFI_ACCESS_DENIED The file specified by File and FileBuffer did not
- authenticate, and the platform policy dictates that the DXE
- Foundation many not use File.
- **/
- EFI_STATUS
- EFIAPI
- DxeImageVerificationHandler (
- IN UINT32 AuthenticationStatus,
- IN CONST EFI_DEVICE_PATH_PROTOCOL *File,
- IN VOID *FileBuffer,
- IN UINTN FileSize,
- IN BOOLEAN BootPolicy
- )
- {
- EFI_STATUS Status;
- EFI_IMAGE_DOS_HEADER *DosHdr;
- EFI_STATUS VerifyStatus;
- EFI_SIGNATURE_LIST *SignatureList;
- UINTN SignatureListSize;
- EFI_SIGNATURE_DATA *Signature;
- EFI_IMAGE_EXECUTION_ACTION Action;
- WIN_CERTIFICATE *WinCertificate;
- UINT32 Policy;
- UINT8 *SecureBoot;
- PE_COFF_LOADER_IMAGE_CONTEXT ImageContext;
- UINT32 NumberOfRvaAndSizes;
- WIN_CERTIFICATE_EFI_PKCS *PkcsCertData;
- WIN_CERTIFICATE_UEFI_GUID *WinCertUefiGuid;
- UINT8 *AuthData;
- UINTN AuthDataSize;
- EFI_IMAGE_DATA_DIRECTORY *SecDataDir;
- UINT32 OffSet;
- CHAR16 *NameStr;
- SignatureList = NULL;
- SignatureListSize = 0;
- WinCertificate = NULL;
- SecDataDir = NULL;
- PkcsCertData = NULL;
- Action = EFI_IMAGE_EXECUTION_AUTH_UNTESTED;
- Status = EFI_ACCESS_DENIED;
- VerifyStatus = EFI_ACCESS_DENIED;
- //
- // Check the image type and get policy setting.
- //
- switch (GetImageType (File)) {
- case IMAGE_FROM_FV:
- Policy = ALWAYS_EXECUTE;
- break;
- case IMAGE_FROM_OPTION_ROM:
- Policy = PcdGet32 (PcdOptionRomImageVerificationPolicy);
- break;
- case IMAGE_FROM_REMOVABLE_MEDIA:
- Policy = PcdGet32 (PcdRemovableMediaImageVerificationPolicy);
- break;
- case IMAGE_FROM_FIXED_MEDIA:
- Policy = PcdGet32 (PcdFixedMediaImageVerificationPolicy);
- break;
- default:
- Policy = DENY_EXECUTE_ON_SECURITY_VIOLATION;
- break;
- }
- //
- // If policy is always/never execute, return directly.
- //
- if (Policy == ALWAYS_EXECUTE) {
- return EFI_SUCCESS;
- } else if (Policy == NEVER_EXECUTE) {
- return EFI_ACCESS_DENIED;
- }
- //
- // The policy QUERY_USER_ON_SECURITY_VIOLATION and ALLOW_EXECUTE_ON_SECURITY_VIOLATION
- // violates the UEFI spec and has been removed.
- //
- ASSERT (Policy != QUERY_USER_ON_SECURITY_VIOLATION && Policy != ALLOW_EXECUTE_ON_SECURITY_VIOLATION);
- if (Policy == QUERY_USER_ON_SECURITY_VIOLATION || Policy == ALLOW_EXECUTE_ON_SECURITY_VIOLATION) {
- CpuDeadLoop ();
- }
- GetEfiGlobalVariable2 (EFI_SECURE_BOOT_MODE_NAME, (VOID**)&SecureBoot, NULL);
- //
- // Skip verification if SecureBoot variable doesn't exist.
- //
- if (SecureBoot == NULL) {
- return EFI_SUCCESS;
- }
- //
- // Skip verification if SecureBoot is disabled but not AuditMode
- //
- if (*SecureBoot == SECURE_BOOT_MODE_DISABLE) {
- FreePool (SecureBoot);
- return EFI_SUCCESS;
- }
- FreePool (SecureBoot);
- //
- // Read the Dos header.
- //
- if (FileBuffer == NULL) {
- return EFI_INVALID_PARAMETER;
- }
- mImageBase = (UINT8 *) FileBuffer;
- mImageSize = FileSize;
- ZeroMem (&ImageContext, sizeof (ImageContext));
- ImageContext.Handle = (VOID *) FileBuffer;
- ImageContext.ImageRead = (PE_COFF_LOADER_READ_FILE) DxeImageVerificationLibImageRead;
- //
- // Get information about the image being loaded
- //
- Status = PeCoffLoaderGetImageInfo (&ImageContext);
- if (EFI_ERROR (Status)) {
- //
- // The information can't be got from the invalid PeImage
- //
- DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: PeImage invalid. Cannot retrieve image information.\n"));
- goto Done;
- }
- Status = EFI_ACCESS_DENIED;
- DosHdr = (EFI_IMAGE_DOS_HEADER *) mImageBase;
- if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) {
- //
- // DOS image header is present,
- // so read the PE header after the DOS image header.
- //
- mPeCoffHeaderOffset = DosHdr->e_lfanew;
- } else {
- mPeCoffHeaderOffset = 0;
- }
- //
- // Check PE/COFF image.
- //
- mNtHeader.Pe32 = (EFI_IMAGE_NT_HEADERS32 *) (mImageBase + mPeCoffHeaderOffset);
- if (mNtHeader.Pe32->Signature != EFI_IMAGE_NT_SIGNATURE) {
- //
- // It is not a valid Pe/Coff file.
- //
- DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Not a valid PE/COFF image.\n"));
- goto Done;
- }
- if (mNtHeader.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
- //
- // Use PE32 offset.
- //
- NumberOfRvaAndSizes = mNtHeader.Pe32->OptionalHeader.NumberOfRvaAndSizes;
- if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
- SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
- }
- } else {
- //
- // Use PE32+ offset.
- //
- NumberOfRvaAndSizes = mNtHeader.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes;
- if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_SECURITY) {
- SecDataDir = (EFI_IMAGE_DATA_DIRECTORY *) &mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
- }
- }
- //
- // Start Image Validation.
- //
- if (SecDataDir == NULL || SecDataDir->Size == 0) {
- //
- // This image is not signed. The SHA256 hash value of the image must match a record in the security database "db",
- // and not be reflected in the security data base "dbx".
- //
- if (!HashPeImage (HASHALG_SHA256)) {
- DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Failed to hash this image using %s.\n", mHashTypeStr));
- goto Done;
- }
- if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) {
- //
- // Image Hash is in forbidden database (DBX).
- //
- DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is not signed and %s hash of image is forbidden by DBX.\n", mHashTypeStr));
- goto Done;
- }
- if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) {
- //
- // Image Hash is in allowed database (DB).
- //
- return EFI_SUCCESS;
- }
- //
- // Image Hash is not found in both forbidden and allowed database.
- //
- DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is not signed and %s hash of image is not found in DB/DBX.\n", mHashTypeStr));
- goto Done;
- }
- //
- // Verify the signature of the image, multiple signatures are allowed as per PE/COFF Section 4.7
- // "Attribute Certificate Table".
- // The first certificate starts at offset (SecDataDir->VirtualAddress) from the start of the file.
- //
- for (OffSet = SecDataDir->VirtualAddress;
- OffSet < (SecDataDir->VirtualAddress + SecDataDir->Size);
- OffSet += (WinCertificate->dwLength + ALIGN_SIZE (WinCertificate->dwLength))) {
- WinCertificate = (WIN_CERTIFICATE *) (mImageBase + OffSet);
- if ((SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) <= sizeof (WIN_CERTIFICATE) ||
- (SecDataDir->VirtualAddress + SecDataDir->Size - OffSet) < WinCertificate->dwLength) {
- break;
- }
- //
- // Verify the image's Authenticode signature, only DER-encoded PKCS#7 signed data is supported.
- //
- if (WinCertificate->wCertificateType == WIN_CERT_TYPE_PKCS_SIGNED_DATA) {
- //
- // The certificate is formatted as WIN_CERTIFICATE_EFI_PKCS which is described in the
- // Authenticode specification.
- //
- PkcsCertData = (WIN_CERTIFICATE_EFI_PKCS *) WinCertificate;
- if (PkcsCertData->Hdr.dwLength <= sizeof (PkcsCertData->Hdr)) {
- break;
- }
- AuthData = PkcsCertData->CertData;
- AuthDataSize = PkcsCertData->Hdr.dwLength - sizeof(PkcsCertData->Hdr);
- } else if (WinCertificate->wCertificateType == WIN_CERT_TYPE_EFI_GUID) {
- //
- // The certificate is formatted as WIN_CERTIFICATE_UEFI_GUID which is described in UEFI Spec.
- //
- WinCertUefiGuid = (WIN_CERTIFICATE_UEFI_GUID *) WinCertificate;
- if (WinCertUefiGuid->Hdr.dwLength <= OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData)) {
- break;
- }
- if (!CompareGuid (&WinCertUefiGuid->CertType, &gEfiCertPkcs7Guid)) {
- continue;
- }
- AuthData = WinCertUefiGuid->CertData;
- AuthDataSize = WinCertUefiGuid->Hdr.dwLength - OFFSET_OF(WIN_CERTIFICATE_UEFI_GUID, CertData);
- } else {
- if (WinCertificate->dwLength < sizeof (WIN_CERTIFICATE)) {
- break;
- }
- continue;
- }
- Status = HashPeImageByType (AuthData, AuthDataSize);
- if (EFI_ERROR (Status)) {
- continue;
- }
- //
- // Check the digital signature against the revoked certificate in forbidden database (dbx).
- //
- if (IsForbiddenByDbx (AuthData, AuthDataSize)) {
- Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED;
- VerifyStatus = EFI_ACCESS_DENIED;
- break;
- }
- //
- // Check the digital signature against the valid certificate in allowed database (db).
- //
- if (EFI_ERROR (VerifyStatus)) {
- if (IsAllowedByDb (AuthData, AuthDataSize)) {
- VerifyStatus = EFI_SUCCESS;
- }
- }
- //
- // Check the image's hash value.
- //
- if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) {
- Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND;
- DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but %s hash of image is found in DBX.\n", mHashTypeStr));
- VerifyStatus = EFI_ACCESS_DENIED;
- break;
- } else if (EFI_ERROR (VerifyStatus)) {
- if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) {
- VerifyStatus = EFI_SUCCESS;
- } else {
- 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));
- }
- }
- }
- if (OffSet != (SecDataDir->VirtualAddress + SecDataDir->Size)) {
- //
- // The Size in Certificate Table or the attribute certicate table is corrupted.
- //
- VerifyStatus = EFI_ACCESS_DENIED;
- }
- if (!EFI_ERROR (VerifyStatus)) {
- return EFI_SUCCESS;
- } else {
- Status = EFI_ACCESS_DENIED;
- if (Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED || Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND) {
- //
- // Get image hash value as executable's signature.
- //
- SignatureListSize = sizeof (EFI_SIGNATURE_LIST) + sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize;
- SignatureList = (EFI_SIGNATURE_LIST *) AllocateZeroPool (SignatureListSize);
- if (SignatureList == NULL) {
- Status = EFI_OUT_OF_RESOURCES;
- goto Done;
- }
- SignatureList->SignatureHeaderSize = 0;
- SignatureList->SignatureListSize = (UINT32) SignatureListSize;
- SignatureList->SignatureSize = (UINT32) (sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize);
- CopyMem (&SignatureList->SignatureType, &mCertType, sizeof (EFI_GUID));
- Signature = (EFI_SIGNATURE_DATA *) ((UINT8 *) SignatureList + sizeof (EFI_SIGNATURE_LIST));
- CopyMem (Signature->SignatureData, mImageDigest, mImageDigestSize);
- }
- }
- Done:
- if (Status != EFI_SUCCESS) {
- //
- // Policy decides to defer or reject the image; add its information in image executable information table.
- //
- NameStr = ConvertDevicePathToText (File, FALSE, TRUE);
- AddImageExeInfo (Action, NameStr, File, SignatureList, SignatureListSize);
- if (NameStr != NULL) {
- DEBUG((EFI_D_INFO, "The image doesn't pass verification: %s\n", NameStr));
- FreePool(NameStr);
- }
- Status = EFI_SECURITY_VIOLATION;
- }
- if (SignatureList != NULL) {
- FreePool (SignatureList);
- }
- return Status;
- }
- /**
- On Ready To Boot Services Event notification handler.
- Add the image execution information table if it is not in system configuration table.
- @param[in] Event Event whose notification function is being invoked
- @param[in] Context Pointer to the notification function's context
- **/
- VOID
- EFIAPI
- OnReadyToBoot (
- IN EFI_EVENT Event,
- IN VOID *Context
- )
- {
- EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable;
- UINTN ImageExeInfoTableSize;
- EfiGetSystemConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID **) &ImageExeInfoTable);
- if (ImageExeInfoTable != NULL) {
- return;
- }
- ImageExeInfoTableSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE);
- ImageExeInfoTable = (EFI_IMAGE_EXECUTION_INFO_TABLE *) AllocateRuntimePool (ImageExeInfoTableSize);
- if (ImageExeInfoTable == NULL) {
- return ;
- }
- ImageExeInfoTable->NumberOfImages = 0;
- gBS->InstallConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID *) ImageExeInfoTable);
- }
- /**
- Register security measurement handler.
- @param ImageHandle ImageHandle of the loaded driver.
- @param SystemTable Pointer to the EFI System Table.
- @retval EFI_SUCCESS The handlers were registered successfully.
- **/
- EFI_STATUS
- EFIAPI
- DxeImageVerificationLibConstructor (
- IN EFI_HANDLE ImageHandle,
- IN EFI_SYSTEM_TABLE *SystemTable
- )
- {
- EFI_EVENT Event;
- //
- // Register the event to publish the image execution table.
- //
- EfiCreateEventReadyToBootEx (
- TPL_CALLBACK,
- OnReadyToBoot,
- NULL,
- &Event
- );
- return RegisterSecurity2Handler (
- DxeImageVerificationHandler,
- EFI_AUTH_OPERATION_VERIFY_IMAGE | EFI_AUTH_OPERATION_IMAGE_REQUIRED
- );
- }
|