InternalIsBufferOverlapped() is created to check overlap between buffers.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <[email protected]>
Reviewed-by: Jiewen Yao <[email protected]>
---
MdeModulePkg/Core/PiSmmCore/PiSmmCore.c | 44 +++++++++++++++++++++++++++++++--
1 file changed, 42 insertions(+), 2 deletions(-)
diff --git a/MdeModulePkg/Core/PiSmmCore/PiSmmCore.c
b/MdeModulePkg/Core/PiSmmCore/PiSmmCore.c
index 55dcf31..496638a 100644
--- a/MdeModulePkg/Core/PiSmmCore/PiSmmCore.c
+++ b/MdeModulePkg/Core/PiSmmCore/PiSmmCore.c
@@ -379,6 +379,37 @@ SmmEndOfDxeHandler (
}
/**
+ Determine if two buffers overlap in memory.
+
+ @param[in] Buff1 Pointer to first buffer
+ @param[in] Size1 Size of Buff1
+ @param[in] Buff2 Pointer to second buffer
+ @param[in] Size2 Size of Buff2
+
+ @retval TRUE Buffers overlap in memory.
+ @retval FALSE Buffer doesn't overlap.
+
+**/
+BOOLEAN
+InternalIsBufferOverlapped (
+ IN UINT8 *Buff1,
+ IN UINTN Size1,
+ IN UINT8 *Buff2,
+ IN UINTN Size2
+ )
+{
+ //
+ // If buff1's end is less than the start of buff2, then it's ok.
+ // Also, if buff1's start is beyond buff2's end, then it's ok.
+ //
+ if (((Buff1 + Size1) <= Buff2) || (Buff1 >= (Buff2 + Size2))) {
+ return FALSE;
+ }
+
+ return TRUE;
+}
+
+/**
The main entry point to SMM Foundation.
Note: This function is only used by SMRAM invocation. It is never used by
DXE invocation.
@@ -396,6 +427,7 @@ SmmEntryPoint (
EFI_STATUS Status;
EFI_SMM_COMMUNICATE_HEADER *CommunicateHeader;
BOOLEAN InLegacyBoot;
+ BOOLEAN IsOverlapped;
PERF_START (NULL, "SMM", NULL, 0) ;
@@ -427,9 +459,17 @@ SmmEntryPoint (
//
// Synchronous SMI for SMM Core or request from Communicate protocol
//
- if (!SmmIsBufferOutsideSmmValid
((UINTN)gSmmCorePrivate->CommunicationBuffer, gSmmCorePrivate->BufferSize)) {
+ IsOverlapped = InternalIsBufferOverlapped (
+ (UINT8 *) gSmmCorePrivate->CommunicationBuffer,
+ gSmmCorePrivate->BufferSize,
+ (UINT8 *) gSmmCorePrivate,
+ sizeof (*gSmmCorePrivate)
+ );
+ if (!SmmIsBufferOutsideSmmValid
((UINTN)gSmmCorePrivate->CommunicationBuffer, gSmmCorePrivate->BufferSize) ||
IsOverlapped) {
//
- // If CommunicationBuffer is not in valid address scope, return
EFI_INVALID_PARAMETER
+ // If CommunicationBuffer is not in valid address scope,
+ // or there is overlap between gSmmCorePrivate and CommunicationBuffer,
+ // return EFI_INVALID_PARAMETER
//
gSmmCorePrivate->CommunicationBuffer = NULL;
gSmmCorePrivate->ReturnStatus = EFI_INVALID_PARAMETER;
--
1.9.5.msysgit.0
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