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StandaloneMmPkg: StandaloneMmCore: Use SafeIntLib for arithmetics

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This change adds the SafeIntLib to communication input routine to
validate the incoming MM communication buffer length before using.

Signed-off-by: Kun Qin <kun.qin@microsoft.com>
This commit is contained in:
Kun Qin 2026-07-10 16:40:58 -07:00
parent 8ef258eff0
commit eae5888e47
3 changed files with 57 additions and 12 deletions
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67
StandaloneMmPkg/Core/StandaloneMmCore.c
View file

@ -513,6 +513,8 @@ MmEntryPoint (
EFI_GUID *CommGuid;
UINTN CommGuidOffset;
UINTN CommHeaderSize;
EFI_STATUS SafeIntStatus;
UINTN MaxBufferSize;
//
// Update MMST using the context
@ -560,10 +562,31 @@ MmEntryPoint (
LegacyCommunicateHeader = (EFI_MM_COMMUNICATE_HEADER *)(UINTN)mMmCommunicationBuffer->PhysicalStart;
CommGuidOffset = OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, HeaderGuid);
CommHeaderSize = OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, Data);
BufferSize = OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, Data) + LegacyCommunicateHeader->MessageLength;
SafeIntStatus = SafeUintnAdd (
OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, Data),
LegacyCommunicateHeader->MessageLength,
&BufferSize
);
if (EFI_ERROR (SafeIntStatus)) {
DEBUG ((DEBUG_ERROR, "Failed to calculate buffer size: %r\n", SafeIntStatus));
ASSERT_EFI_ERROR (SafeIntStatus);
return;
}
}
if (BufferSize <= EFI_PAGES_TO_SIZE (mMmCommunicationBuffer->NumberOfPages)) {
SafeIntStatus = SafeUintnMult (
EFI_PAGE_SIZE,
mMmCommunicationBuffer->NumberOfPages,
&MaxBufferSize
);
if (EFI_ERROR (SafeIntStatus)) {
DEBUG ((DEBUG_ERROR, "Failed to convert number of pages to bytes: %r\n", SafeIntStatus));
ASSERT_EFI_ERROR (SafeIntStatus);
return;
}
if (BufferSize <= MaxBufferSize) {
//
// Shadow the data from MM Communication Buffer to internal buffer
//
@ -574,19 +597,39 @@ MmEntryPoint (
);
ZeroMem (
(UINT8 *)mInternalCommBufferCopy + BufferSize,
EFI_PAGES_TO_SIZE (mMmCommunicationBuffer->NumberOfPages) - BufferSize
MaxBufferSize - BufferSize
);
BufferSize -= CommHeaderSize;
Status = MmiManage (
(EFI_GUID *)((UINT8 *)mInternalCommBufferCopy + CommGuidOffset),
NULL,
(UINT8 *)mInternalCommBufferCopy + CommHeaderSize,
&BufferSize
);
SafeIntStatus = SafeUintnSub (
BufferSize,
CommHeaderSize,
&BufferSize
);
if (EFI_ERROR (SafeIntStatus)) {
DEBUG ((DEBUG_ERROR, "Failed to subtract header from buffer size: %r\n", SafeIntStatus));
ASSERT_EFI_ERROR (SafeIntStatus);
return;
}
BufferSize = BufferSize + CommHeaderSize;
if (BufferSize <= EFI_PAGES_TO_SIZE (mMmCommunicationBuffer->NumberOfPages)) {
Status = MmiManage (
(EFI_GUID *)((UINT8 *)mInternalCommBufferCopy + CommGuidOffset),
NULL,
(UINT8 *)mInternalCommBufferCopy + CommHeaderSize,
&BufferSize
);
SafeIntStatus = SafeUintnAdd (
BufferSize,
CommHeaderSize,
&BufferSize
);
if (EFI_ERROR (SafeIntStatus)) {
DEBUG ((DEBUG_ERROR, "Failed to calculate total buffer size: %r\n", SafeIntStatus));
ASSERT_EFI_ERROR (SafeIntStatus);
return;
}
if (BufferSize <= MaxBufferSize) {
//
// Copy the data back to MM Communication Buffer
//

1
StandaloneMmPkg/Core/StandaloneMmCore.h
View file

@ -47,6 +47,7 @@
#include <Library/StandaloneMmMemLib.h>
#include <Library/HobLib.h>
#include <Library/PerformanceLib.h>
#include <Library/SafeIntLib.h>
#include "StandaloneMmCorePrivateData.h"

1
StandaloneMmPkg/Core/StandaloneMmCore.inf
View file

@ -54,6 +54,7 @@
HobPrintLib
ImagePropertiesRecordLib
PerformanceLib
SafeIntLib
[Protocols]
gEfiDxeMmReadyToLockProtocolGuid ## UNDEFINED # SmiHandlerRegister