[edk2-devel] [PATCH v3 6/7] StandaloneMmPkg: StandaloneMmCore: Parsing new MM communicate header

[Kun Qin]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3398
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3430

MM communicate protocols are expanded with EFI_MM_COMMUNICATE_HEADER_V3
structure that cooperates with updated field types and flexible array.
The PiSmmCore implementation is updated to detect and process incoming
data accordingly.

Two checks are also performed to prevent legacy communicate data or
unsupported data is fed into MM core under agreed header guid.

Cc: Ard Biesheuvel <ardb+tianoc...@kernel.org>
Cc: Sami Mujawar <sami.muja...@arm.com>
Cc: Jiewen Yao <jiewen....@intel.com>
Cc: Supreeth Venkatesh <supreeth.venkat...@arm.com>

Signed-off-by: Kun Qin <kuqi...@gmail.com>
---

Notes:
    v3:
    - Newly added

 StandaloneMmPkg/Core/StandaloneMmCore.c   | 34 ++++++++++++++++----
 StandaloneMmPkg/Core/StandaloneMmCore.inf |  1 +
 2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/StandaloneMmPkg/Core/StandaloneMmCore.c 
b/StandaloneMmPkg/Core/StandaloneMmCore.c
index fbb0ec75e557..000aca098cc8 100644
--- a/StandaloneMmPkg/Core/StandaloneMmCore.c
+++ b/StandaloneMmPkg/Core/StandaloneMmCore.c
@@ -340,8 +340,12 @@ MmEntryPoint (
   IN CONST EFI_MM_ENTRY_CONTEXT  *MmEntryContext
 )
 {
-  EFI_STATUS                  Status;
-  EFI_MM_COMMUNICATE_HEADER  *CommunicateHeader;
+  EFI_STATUS                    Status;
+  EFI_MM_COMMUNICATE_HEADER_V3  *CommunicateHeader;
+  EFI_MM_COMMUNICATE_HEADER     *LegacyCommunicateHeader;
+  EFI_GUID                      *CommGuid;
+  VOID                          *CommData;
+  UINTN                         CommHeaderSize;
 
   DEBUG ((DEBUG_INFO, "MmEntryPoint ...\n"));
 
@@ -379,19 +383,35 @@ MmEntryPoint (
       gMmCorePrivate->CommunicationBuffer = 0;
       gMmCorePrivate->ReturnStatus = EFI_INVALID_PARAMETER;
     } else {
-      CommunicateHeader = (EFI_MM_COMMUNICATE_HEADER 
*)(UINTN)gMmCorePrivate->CommunicationBuffer;
-      gMmCorePrivate->BufferSize -= OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, 
Data);
+      CommGuid = &((EFI_MM_COMMUNICATE_HEADER_V3 
*)(UINTN)gMmCorePrivate->CommunicationBuffer)->HeaderGuid;
+      //
+      // Check if the signature matches EFI_MM_COMMUNICATE_HEADER_V3 definition
+      //
+      if (CompareGuid (CommGuid, &gCommunicateHeaderV3Guid)) {
+        CommunicateHeader = (EFI_MM_COMMUNICATE_HEADER_V3 
*)(UINTN)gMmCorePrivate->CommunicationBuffer;
+        ASSERT (CommunicateHeader->Signature == 
EFI_MM_COMMUNICATE_HEADER_V3_SIGNATURE);
+        ASSERT (CommunicateHeader->Version <= 
EFI_MM_COMMUNICATE_HEADER_V3_VERSION);
+        CommGuid = &CommunicateHeader->MessageGuid;
+        CommData = CommunicateHeader->MessageData;
+        CommHeaderSize = sizeof (EFI_MM_COMMUNICATE_HEADER_V3);
+      } else {
+        LegacyCommunicateHeader = (EFI_MM_COMMUNICATE_HEADER 
*)(UINTN)gMmCorePrivate->CommunicationBuffer;
+        CommGuid = &LegacyCommunicateHeader->HeaderGuid;
+        CommData = LegacyCommunicateHeader->Data;
+        CommHeaderSize = OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, Data);
+      }
+      gMmCorePrivate->BufferSize -= CommHeaderSize;
       Status = MmiManage (
-                 &CommunicateHeader->HeaderGuid,
+                 CommGuid,
                  NULL,
-                 CommunicateHeader->Data,
+                 CommData,
                  (UINTN *)&gMmCorePrivate->BufferSize
                  );
       //
       // Update CommunicationBuffer, BufferSize and ReturnStatus
       // Communicate service finished, reset the pointer to CommBuffer to NULL
       //
-      gMmCorePrivate->BufferSize += OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, 
Data);
+      gMmCorePrivate->BufferSize += CommHeaderSize;
       gMmCorePrivate->CommunicationBuffer = 0;
       gMmCorePrivate->ReturnStatus = (Status == EFI_SUCCESS) ? EFI_SUCCESS : 
EFI_NOT_FOUND;
     }
diff --git a/StandaloneMmPkg/Core/StandaloneMmCore.inf 
b/StandaloneMmPkg/Core/StandaloneMmCore.inf
index 56042b7b39f4..41a49e23fa8f 100644
--- a/StandaloneMmPkg/Core/StandaloneMmCore.inf
+++ b/StandaloneMmPkg/Core/StandaloneMmCore.inf
@@ -75,6 +75,7 @@ [Guids]
   gEfiEventLegacyBootGuid
   gEfiEventExitBootServicesGuid
   gEfiEventReadyToBootGuid
+  gCommunicateHeaderV3Guid    ## CONSUMES   ## GUID # Communicate header
 
 [BuildOptions]
   GCC:*_*_*_CC_FLAGS = -fpie
-- 
2.32.0.windows.1



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