/** @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[] = { | |
#ifndef DISABLE_SHA1_DEPRECATED_INTERFACES | |
{ L"SHA1", 20, &mHashOidValue[0], 5, Sha1GetContextSize, Sha1Init, Sha1Update, Sha1Final }, | |
#else | |
{ L"SHA1", 20, &mHashOidValue[0], 5, NULL, NULL, NULL, NULL }, | |
#endif | |
{ 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) { | |
#ifndef DISABLE_SHA1_DEPRECATED_INTERFACES | |
case HASHALG_SHA1: | |
mImageDigestSize = SHA1_DIGEST_SIZE; | |
mCertType = gEfiCertSha1Guid; | |
break; | |
#endif | |
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. Must be zero if Signature is NULL. | |
**/ | |
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 accommodate 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 | |
// | |
ASSERT (Signature != NULL || SignatureSize == 0); | |
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. | |
@param[out] IsFound Search result. Only valid if EFI_SUCCESS returned. | |
@retval EFI_SUCCESS Finished the search without any error. | |
@retval Others Error occurred in the search of database. | |
**/ | |
EFI_STATUS | |
IsCertHashFoundInDbx ( | |
IN UINT8 *Certificate, | |
IN UINTN CertSize, | |
IN EFI_SIGNATURE_LIST *SignatureList, | |
IN UINTN SignatureListSize, | |
OUT EFI_TIME *RevocationTime, | |
OUT BOOLEAN *IsFound | |
) | |
{ | |
EFI_STATUS 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; | |
Status = EFI_ABORTED; | |
*IsFound = FALSE; | |
DbxList = SignatureList; | |
DbxSize = SignatureListSize; | |
HashCtx = NULL; | |
HashAlg = HASHALG_MAX; | |
if ((RevocationTime == NULL) || (DbxList == NULL)) { | |
return EFI_INVALID_PARAMETER; | |
} | |
// | |
// Retrieve the TBSCertificate from the X.509 Certificate. | |
// | |
if (!X509GetTBSCert (Certificate, CertSize, &TBSCert, &TBSCertSize)) { | |
return Status; | |
} | |
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; | |
} | |
if (!mHash[HashAlg].HashInit (HashCtx)) { | |
goto Done; | |
} | |
if (!mHash[HashAlg].HashUpdate (HashCtx, TBSCert, TBSCertSize)) { | |
goto Done; | |
} | |
if (!mHash[HashAlg].HashFinal (HashCtx, CertDigest)) { | |
goto Done; | |
} | |
FreePool (HashCtx); | |
HashCtx = NULL; | |
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. | |
// | |
Status = EFI_SUCCESS; | |
*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); | |
} | |
Status = EFI_SUCCESS; | |
Done: | |
if (HashCtx != NULL) { | |
FreePool (HashCtx); | |
} | |
return Status; | |
} | |
/** | |
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 algorithm. | |
@param[in] SignatureSize Size of Signature. | |
@param[out] IsFound Search result. Only valid if EFI_SUCCESS returned | |
@retval EFI_SUCCESS Finished the search without any error. | |
@retval Others Error occurred in the search of database. | |
**/ | |
EFI_STATUS | |
IsSignatureFoundInDatabase ( | |
IN CHAR16 *VariableName, | |
IN UINT8 *Signature, | |
IN EFI_GUID *CertType, | |
IN UINTN SignatureSize, | |
OUT BOOLEAN *IsFound | |
) | |
{ | |
EFI_STATUS Status; | |
EFI_SIGNATURE_LIST *CertList; | |
EFI_SIGNATURE_DATA *Cert; | |
UINTN DataSize; | |
UINT8 *Data; | |
UINTN Index; | |
UINTN CertCount; | |
// | |
// Read signature database variable. | |
// | |
*IsFound = FALSE; | |
Data = NULL; | |
DataSize = 0; | |
Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL); | |
if (Status != EFI_BUFFER_TOO_SMALL) { | |
if (Status == EFI_NOT_FOUND) { | |
// | |
// No database, no need to search. | |
// | |
Status = EFI_SUCCESS; | |
} | |
return Status; | |
} | |
Data = (UINT8 *)AllocateZeroPool (DataSize); | |
if (Data == NULL) { | |
return EFI_OUT_OF_RESOURCES; | |
} | |
Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, Data); | |
if (EFI_ERROR (Status)) { | |
goto Done; | |
} | |
// | |
// Enumerate all signature data in SigDB to check if signature exists for executable. | |
// | |
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 Status; | |
} | |
/** | |
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; | |
BOOLEAN IsFound; | |
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 = TRUE; | |
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); | |
ASSERT (EFI_ERROR (Status)); | |
if (Status != EFI_BUFFER_TOO_SMALL) { | |
if (Status == EFI_NOT_FOUND) { | |
// | |
// Evidently not in dbx if the database doesn't exist. | |
// | |
IsForbidden = FALSE; | |
} | |
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)) { | |
goto Done; | |
} | |
// | |
// 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) || ((*CertBuffer) == 0)) { | |
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; | |
Status = IsCertHashFoundInDbx (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data, DataSize, &RevocationTime, &IsFound); | |
if (EFI_ERROR (Status)) { | |
// | |
// Error in searching dbx. Consider it as 'found'. RevocationTime might | |
// not be valid in such situation. | |
// | |
IsForbidden = TRUE; | |
} else if (IsFound) { | |
// | |
// Found Cert in dbx successfully. Check the timestamp signature and | |
// signing time to determine if the image can be trusted. | |
// | |
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; | |
} else { | |
IsForbidden = TRUE; | |
DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature failed the timestamp check.\n")); | |
goto Done; | |
} | |
} | |
} | |
IsForbidden = FALSE; | |
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; | |
BOOLEAN IsFound; | |
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; | |
// | |
// Fetch 'db' content. If 'db' doesn't exist or encounters problem to get the | |
// data, return not-allowed-by-db (FALSE). | |
// | |
DataSize = 0; | |
Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL); | |
ASSERT (EFI_ERROR (Status)); | |
if (Status != EFI_BUFFER_TOO_SMALL) { | |
return VerifyStatus; | |
} | |
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; | |
} | |
// | |
// Fetch 'dbx' content. If 'dbx' doesn't exist, continue to check 'db'. | |
// If any other errors occurred, no need to check 'db' but just return | |
// not-allowed-by-db (FALSE) to avoid bypass. | |
// | |
DbxDataSize = 0; | |
Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, NULL); | |
ASSERT (EFI_ERROR (Status)); | |
if (Status != EFI_BUFFER_TOO_SMALL) { | |
if (Status != EFI_NOT_FOUND) { | |
goto Done; | |
} | |
// | |
// 'dbx' does not exist. Continue to check 'db'. | |
// | |
} else { | |
// | |
// 'dbx' exists. Get its content. | |
// | |
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; | |
} | |
} | |
// | |
// 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) { | |
// | |
// The image is signed and its signature is found in 'db'. | |
// | |
if (DbxData != NULL) { | |
// | |
// Here We still need to check if this RootCert's Hash is revoked | |
// | |
Status = IsCertHashFoundInDbx (RootCert, RootCertSize, (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime, &IsFound); | |
if (EFI_ERROR (Status)) { | |
// | |
// Error in searching dbx. Consider it as 'found'. RevocationTime might | |
// not be valid in such situation. | |
// | |
VerifyStatus = FALSE; | |
} else if (IsFound) { | |
// | |
// 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")); | |
} | |
} | |
} | |
// | |
// There's no 'dbx' to check revocation time against (must-be pass), | |
// or, there's revocation time found in 'dbx' and checked againt 'dbt' | |
// (maybe pass or fail, depending on timestamp compare result). Either | |
// way the verification job has been completed at this point. | |
// | |
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 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_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 may not use File. The image has | |
been added to the file execution table. | |
**/ | |
EFI_STATUS | |
EFIAPI | |
DxeImageVerificationHandler ( | |
IN UINT32 AuthenticationStatus, | |
IN CONST EFI_DEVICE_PATH_PROTOCOL *File OPTIONAL, | |
IN VOID *FileBuffer, | |
IN UINTN FileSize, | |
IN BOOLEAN BootPolicy | |
) | |
{ | |
EFI_IMAGE_DOS_HEADER *DosHdr; | |
BOOLEAN IsVerified; | |
EFI_SIGNATURE_LIST *SignatureList; | |
UINTN SignatureListSize; | |
EFI_SIGNATURE_DATA *Signature; | |
EFI_IMAGE_EXECUTION_ACTION Action; | |
WIN_CERTIFICATE *WinCertificate; | |
UINT32 Policy; | |
UINT8 SecureBoot; | |
UINTN SecureBootSize; | |
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 SecDataDirEnd; | |
UINT32 SecDataDirLeft; | |
UINT32 OffSet; | |
CHAR16 *NameStr; | |
RETURN_STATUS PeCoffStatus; | |
EFI_STATUS HashStatus; | |
EFI_STATUS DbStatus; | |
EFI_STATUS VarStatus; | |
UINT32 VarAttr; | |
BOOLEAN IsFound; | |
UINT8 HashAlg; | |
BOOLEAN IsFoundInDatabase; | |
SignatureList = NULL; | |
SignatureListSize = 0; | |
WinCertificate = NULL; | |
SecDataDir = NULL; | |
PkcsCertData = NULL; | |
Action = EFI_IMAGE_EXECUTION_AUTH_UNTESTED; | |
IsVerified = FALSE; | |
IsFound = FALSE; | |
IsFoundInDatabase = FALSE; | |
// | |
// 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; | |
} | |
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 (); | |
} | |
SecureBootSize = sizeof (SecureBoot); | |
VarStatus = gRT->GetVariable (EFI_SECURE_BOOT_MODE_NAME, &gEfiGlobalVariableGuid, &VarAttr, &SecureBootSize, &SecureBoot); | |
// | |
// Skip verification if SecureBoot variable doesn't exist. | |
// | |
if (VarStatus == EFI_NOT_FOUND) { | |
return EFI_SUCCESS; | |
} | |
// | |
// Skip verification if SecureBoot is disabled but not AuditMode | |
// | |
if ((VarStatus == EFI_SUCCESS) && | |
(VarAttr == (EFI_VARIABLE_BOOTSERVICE_ACCESS | | |
EFI_VARIABLE_RUNTIME_ACCESS)) && | |
(SecureBoot == SECURE_BOOT_MODE_DISABLE)) | |
{ | |
return EFI_SUCCESS; | |
} | |
// | |
// Read the Dos header. | |
// | |
if (FileBuffer == NULL) { | |
return EFI_ACCESS_DENIED; | |
} | |
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 | |
// | |
PeCoffStatus = PeCoffLoaderGetImageInfo (&ImageContext); | |
if (RETURN_ERROR (PeCoffStatus)) { | |
// | |
// The information can't be got from the invalid PeImage | |
// | |
DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: PeImage invalid. Cannot retrieve image information.\n")); | |
goto Failed; | |
} | |
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 Failed; | |
} | |
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 hash value of the image must match a record in the security database "db", | |
// and not be reflected in the security data base "dbx". | |
// | |
HashAlg = sizeof (mHash) / sizeof (HASH_TABLE); | |
while (HashAlg > 0) { | |
HashAlg--; | |
if ((mHash[HashAlg].GetContextSize == NULL) || (mHash[HashAlg].HashInit == NULL) || (mHash[HashAlg].HashUpdate == NULL) || (mHash[HashAlg].HashFinal == NULL)) { | |
continue; | |
} | |
if (!HashPeImage (HashAlg)) { | |
continue; | |
} | |
DbStatus = IsSignatureFoundInDatabase ( | |
EFI_IMAGE_SECURITY_DATABASE1, | |
mImageDigest, | |
&mCertType, | |
mImageDigestSize, | |
&IsFound | |
); | |
if (EFI_ERROR (DbStatus) || IsFound) { | |
// | |
// 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 Failed; | |
} | |
DbStatus = IsSignatureFoundInDatabase ( | |
EFI_IMAGE_SECURITY_DATABASE, | |
mImageDigest, | |
&mCertType, | |
mImageDigestSize, | |
&IsFound | |
); | |
if (!EFI_ERROR (DbStatus) && IsFound) { | |
// | |
// Image Hash is in allowed database (DB). | |
// | |
IsFoundInDatabase = TRUE; | |
} | |
} | |
if (IsFoundInDatabase) { | |
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 Failed; | |
} | |
// | |
// 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. | |
// | |
SecDataDirEnd = SecDataDir->VirtualAddress + SecDataDir->Size; | |
for (OffSet = SecDataDir->VirtualAddress; | |
OffSet < SecDataDirEnd; | |
OffSet += (WinCertificate->dwLength + ALIGN_SIZE (WinCertificate->dwLength))) | |
{ | |
SecDataDirLeft = SecDataDirEnd - OffSet; | |
if (SecDataDirLeft <= sizeof (WIN_CERTIFICATE)) { | |
break; | |
} | |
WinCertificate = (WIN_CERTIFICATE *)(mImageBase + OffSet); | |
if ((SecDataDirLeft < WinCertificate->dwLength) || | |
(SecDataDirLeft - WinCertificate->dwLength < | |
ALIGN_SIZE (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; | |
} | |
HashStatus = HashPeImageByType (AuthData, AuthDataSize); | |
if (EFI_ERROR (HashStatus)) { | |
continue; | |
} | |
// | |
// Check the digital signature against the revoked certificate in forbidden database (dbx). | |
// | |
if (IsForbiddenByDbx (AuthData, AuthDataSize)) { | |
Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED; | |
IsVerified = FALSE; | |
break; | |
} | |
// | |
// Check the digital signature against the valid certificate in allowed database (db). | |
// | |
if (!IsVerified) { | |
if (IsAllowedByDb (AuthData, AuthDataSize)) { | |
IsVerified = TRUE; | |
} | |
} | |
// | |
// Check the image's hash value. | |
// | |
DbStatus = IsSignatureFoundInDatabase ( | |
EFI_IMAGE_SECURITY_DATABASE1, | |
mImageDigest, | |
&mCertType, | |
mImageDigestSize, | |
&IsFound | |
); | |
if (EFI_ERROR (DbStatus) || IsFound) { | |
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)); | |
IsVerified = FALSE; | |
break; | |
} | |
if (!IsVerified) { | |
DbStatus = IsSignatureFoundInDatabase ( | |
EFI_IMAGE_SECURITY_DATABASE, | |
mImageDigest, | |
&mCertType, | |
mImageDigestSize, | |
&IsFound | |
); | |
if (!EFI_ERROR (DbStatus) && IsFound) { | |
IsVerified = TRUE; | |
} else { | |
Action = EFI_IMAGE_EXECUTION_AUTH_SIG_NOT_FOUND; | |
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 != SecDataDirEnd) { | |
// | |
// The Size in Certificate Table or the attribute certificate table is corrupted. | |
// | |
IsVerified = FALSE; | |
} | |
if (IsVerified) { | |
return EFI_SUCCESS; | |
} | |
if ((Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED) || (Action == EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND)) { | |
// | |
// Get image hash value as signature of executable. | |
// | |
SignatureListSize = sizeof (EFI_SIGNATURE_LIST) + sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize; | |
SignatureList = (EFI_SIGNATURE_LIST *)AllocateZeroPool (SignatureListSize); | |
if (SignatureList == NULL) { | |
SignatureListSize = 0; | |
goto Failed; | |
} | |
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); | |
} | |
Failed: | |
// | |
// Policy decides to defer or reject the image; add its information in image | |
// executable information table in either case. | |
// | |
NameStr = ConvertDevicePathToText (File, FALSE, TRUE); | |
AddImageExeInfo (Action, NameStr, File, SignatureList, SignatureListSize); | |
if (NameStr != NULL) { | |
DEBUG ((DEBUG_INFO, "The image doesn't pass verification: %s\n", NameStr)); | |
FreePool (NameStr); | |
} | |
if (SignatureList != NULL) { | |
FreePool (SignatureList); | |
} | |
if (Policy == DEFER_EXECUTE_ON_SECURITY_VIOLATION) { | |
return EFI_SECURITY_VIOLATION; | |
} | |
return EFI_ACCESS_DENIED; | |
} | |
/** | |
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 | |
); | |
} |