diff options
Diffstat (limited to 'SecurityPkg/Library/DxeTpm2MeasureBootLib/DxeTpm2MeasureBootLibSanitization.c')
| -rw-r--r-- | SecurityPkg/Library/DxeTpm2MeasureBootLib/DxeTpm2MeasureBootLibSanitization.c | 275 |
1 files changed, 275 insertions, 0 deletions
diff --git a/SecurityPkg/Library/DxeTpm2MeasureBootLib/DxeTpm2MeasureBootLibSanitization.c b/SecurityPkg/Library/DxeTpm2MeasureBootLib/DxeTpm2MeasureBootLibSanitization.c new file mode 100644 index 0000000000..e2309655d3 --- /dev/null +++ b/SecurityPkg/Library/DxeTpm2MeasureBootLib/DxeTpm2MeasureBootLibSanitization.c @@ -0,0 +1,275 @@ +/** @file
+ The library instance provides security service of TPM2 measure boot and
+ Confidential Computing (CC) measure boot.
+
+ Caution: This file requires additional review when modified.
+ This library will have external input - PE/COFF image and GPT partition.
+ This external input must be validated carefully to avoid security issue like
+ buffer overflow, integer overflow.
+
+ This file will pull out the validation logic from the following functions, in an
+ attempt to validate the untrusted input in the form of unit tests
+
+ These are those functions:
+
+ DxeTpm2MeasureBootLibImageRead() function will make sure the PE/COFF image content
+ read is within the image buffer.
+
+ Tcg2MeasureGptTable() function will receive untrusted GPT partition table, and parse
+ partition data carefully.
+
+ Copyright (c) Microsoft Corporation.<BR>
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+#include <Uefi.h>
+#include <Uefi/UefiSpec.h>
+#include <Library/SafeIntLib.h>
+#include <Library/UefiLib.h>
+#include <Library/DebugLib.h>
+#include <Library/BaseLib.h>
+#include <IndustryStandard/UefiTcgPlatform.h>
+#include <Protocol/BlockIo.h>
+#include <Library/MemoryAllocationLib.h>
+
+#include "DxeTpm2MeasureBootLibSanitization.h"
+
+#define GPT_HEADER_REVISION_V1 0x00010000
+
+/**
+ This function will validate the EFI_PARTITION_TABLE_HEADER structure is safe to parse
+ However this function will not attempt to verify the validity of the GPT partition
+ It will check the following:
+ - Signature
+ - Revision
+ - AlternateLBA
+ - FirstUsableLBA
+ - LastUsableLBA
+ - PartitionEntryLBA
+ - NumberOfPartitionEntries
+ - SizeOfPartitionEntry
+ - BlockIo
+
+ @param[in] PrimaryHeader
+ Pointer to the EFI_PARTITION_TABLE_HEADER structure.
+
+ @param[in] BlockIo
+ Pointer to the EFI_BLOCK_IO_PROTOCOL structure.
+
+ @retval EFI_SUCCESS
+ The EFI_PARTITION_TABLE_HEADER structure is valid.
+
+ @retval EFI_INVALID_PARAMETER
+ The EFI_PARTITION_TABLE_HEADER structure is invalid.
+**/
+EFI_STATUS
+EFIAPI
+SanitizeEfiPartitionTableHeader (
+ IN CONST EFI_PARTITION_TABLE_HEADER *PrimaryHeader,
+ IN CONST EFI_BLOCK_IO_PROTOCOL *BlockIo
+ )
+{
+ //
+ // Verify that the input parameters are safe to use
+ //
+ if (PrimaryHeader == NULL) {
+ DEBUG ((DEBUG_ERROR, "Invalid Partition Table Header!\n"));
+ return EFI_INVALID_PARAMETER;
+ }
+
+ if ((BlockIo == NULL) || (BlockIo->Media == NULL)) {
+ DEBUG ((DEBUG_ERROR, "Invalid BlockIo!\n"));
+ return EFI_INVALID_PARAMETER;
+ }
+
+ //
+ // The signature must be EFI_PTAB_HEADER_ID ("EFI PART" in ASCII)
+ //
+ if (PrimaryHeader->Header.Signature != EFI_PTAB_HEADER_ID) {
+ DEBUG ((DEBUG_ERROR, "Invalid Partition Table Header!\n"));
+ return EFI_DEVICE_ERROR;
+ }
+
+ //
+ // The version must be GPT_HEADER_REVISION_V1 (0x00010000)
+ //
+ if (PrimaryHeader->Header.Revision != GPT_HEADER_REVISION_V1) {
+ DEBUG ((DEBUG_ERROR, "Invalid Partition Table Header Revision!\n"));
+ return EFI_DEVICE_ERROR;
+ }
+
+ //
+ // The HeaderSize must be greater than or equal to 92 and must be less than or equal to the logical block size
+ //
+ if ((PrimaryHeader->Header.HeaderSize < sizeof (EFI_PARTITION_TABLE_HEADER)) || (PrimaryHeader->Header.HeaderSize > BlockIo->Media->BlockSize)) {
+ DEBUG ((DEBUG_ERROR, "Invalid Partition Table Header HeaderSize!\n"));
+ return EFI_DEVICE_ERROR;
+ }
+
+ //
+ // The partition entries should all be before the first usable block
+ //
+ if (PrimaryHeader->FirstUsableLBA <= PrimaryHeader->PartitionEntryLBA) {
+ DEBUG ((DEBUG_ERROR, "GPT PartitionEntryLBA is not less than FirstUsableLBA!\n"));
+ return EFI_DEVICE_ERROR;
+ }
+
+ //
+ // Check that the PartitionEntryLBA greater than the Max LBA
+ // This will be used later for multiplication
+ //
+ if (PrimaryHeader->PartitionEntryLBA > DivU64x32 (MAX_UINT64, BlockIo->Media->BlockSize)) {
+ DEBUG ((DEBUG_ERROR, "Invalid Partition Table Header PartitionEntryLBA!\n"));
+ return EFI_DEVICE_ERROR;
+ }
+
+ //
+ // Check that the number of partition entries is greater than zero
+ //
+ if (PrimaryHeader->NumberOfPartitionEntries == 0) {
+ DEBUG ((DEBUG_ERROR, "Invalid Partition Table Header NumberOfPartitionEntries!\n"));
+ return EFI_DEVICE_ERROR;
+ }
+
+ //
+ // SizeOfPartitionEntry must be 128, 256, 512... improper size may lead to accessing uninitialized memory
+ //
+ if ((PrimaryHeader->SizeOfPartitionEntry < 128) || ((PrimaryHeader->SizeOfPartitionEntry & (PrimaryHeader->SizeOfPartitionEntry - 1)) != 0)) {
+ DEBUG ((DEBUG_ERROR, "SizeOfPartitionEntry shall be set to a value of 128 x 2^n where n is an integer greater than or equal to zero (e.g., 128, 256, 512, etc.)!\n"));
+ return EFI_DEVICE_ERROR;
+ }
+
+ //
+ // This check is to prevent overflow when calculating the allocation size for the partition entries
+ // This check will be used later for multiplication
+ //
+ if (PrimaryHeader->NumberOfPartitionEntries > DivU64x32 (MAX_UINT64, PrimaryHeader->SizeOfPartitionEntry)) {
+ DEBUG ((DEBUG_ERROR, "Invalid Partition Table Header NumberOfPartitionEntries!\n"));
+ return EFI_DEVICE_ERROR;
+ }
+
+ return EFI_SUCCESS;
+}
+
+/**
+ This function will validate that the allocation size from the primary header is sane
+ It will check the following:
+ - AllocationSize does not overflow
+
+ @param[in] PrimaryHeader
+ Pointer to the EFI_PARTITION_TABLE_HEADER structure.
+
+ @param[out] AllocationSize
+ Pointer to the allocation size.
+
+ @retval EFI_SUCCESS
+ The allocation size is valid.
+
+ @retval EFI_OUT_OF_RESOURCES
+ The allocation size is invalid.
+**/
+EFI_STATUS
+EFIAPI
+SanitizePrimaryHeaderAllocationSize (
+ IN CONST EFI_PARTITION_TABLE_HEADER *PrimaryHeader,
+ OUT UINT32 *AllocationSize
+ )
+{
+ EFI_STATUS Status;
+
+ if (PrimaryHeader == NULL) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ if (AllocationSize == NULL) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ //
+ // Replacing logic:
+ // PrimaryHeader->NumberOfPartitionEntries * PrimaryHeader->SizeOfPartitionEntry;
+ //
+ Status = SafeUint32Mult (PrimaryHeader->NumberOfPartitionEntries, PrimaryHeader->SizeOfPartitionEntry, AllocationSize);
+ if (EFI_ERROR (Status)) {
+ DEBUG ((DEBUG_ERROR, "Allocation Size would have overflowed!\n"));
+ return EFI_BAD_BUFFER_SIZE;
+ }
+
+ return EFI_SUCCESS;
+}
+
+/**
+ This function will validate that the Gpt Event Size calculated from the primary header is sane
+ It will check the following:
+ - EventSize does not overflow
+
+ Important: This function includes the entire length of the allocated space, including
+ (sizeof (EFI_TCG2_EVENT) - sizeof (Tcg2Event->Event)) . When hashing the buffer allocated with this
+ size, the caller must subtract the size of the (sizeof (EFI_TCG2_EVENT) - sizeof (Tcg2Event->Event))
+ from the size of the buffer before hashing.
+
+ @param[in] PrimaryHeader - Pointer to the EFI_PARTITION_TABLE_HEADER structure.
+ @param[in] NumberOfPartition - Number of partitions.
+ @param[out] EventSize - Pointer to the event size.
+
+ @retval EFI_SUCCESS
+ The event size is valid.
+
+ @retval EFI_OUT_OF_RESOURCES
+ Overflow would have occurred.
+
+ @retval EFI_INVALID_PARAMETER
+ One of the passed parameters was invalid.
+**/
+EFI_STATUS
+SanitizePrimaryHeaderGptEventSize (
+ IN CONST EFI_PARTITION_TABLE_HEADER *PrimaryHeader,
+ IN UINTN NumberOfPartition,
+ OUT UINT32 *EventSize
+ )
+{
+ EFI_STATUS Status;
+ UINT32 SafeNumberOfPartitions;
+
+ if (PrimaryHeader == NULL) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ if (EventSize == NULL) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ //
+ // We shouldn't even attempt to perform the multiplication if the number of partitions is greater than the maximum value of UINT32
+ //
+ Status = SafeUintnToUint32 (NumberOfPartition, &SafeNumberOfPartitions);
+ if (EFI_ERROR (Status)) {
+ DEBUG ((DEBUG_ERROR, "NumberOfPartition would have overflowed!\n"));
+ return EFI_INVALID_PARAMETER;
+ }
+
+ //
+ // Replacing logic:
+ // (UINT32)(sizeof (EFI_GPT_DATA) - sizeof (GptData->Partitions) + NumberOfPartition * PrimaryHeader.SizeOfPartitionEntry);
+ //
+ Status = SafeUint32Mult (SafeNumberOfPartitions, PrimaryHeader->SizeOfPartitionEntry, EventSize);
+ if (EFI_ERROR (Status)) {
+ DEBUG ((DEBUG_ERROR, "Event Size would have overflowed!\n"));
+ return EFI_BAD_BUFFER_SIZE;
+ }
+
+ //
+ // Replacing logic:
+ // *EventSize + sizeof (EFI_TCG2_EVENT) - sizeof (Tcg2Event->Event);
+ //
+ Status = SafeUint32Add (
+ OFFSET_OF (EFI_TCG2_EVENT, Event) + OFFSET_OF (EFI_GPT_DATA, Partitions),
+ *EventSize,
+ EventSize
+ );
+ if (EFI_ERROR (Status)) {
+ DEBUG ((DEBUG_ERROR, "Event Size would have overflowed because of GPTData!\n"));
+ return EFI_BAD_BUFFER_SIZE;
+ }
+
+ return EFI_SUCCESS;
+}
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