[edk2] [PATCH] fix unaligned access in SerializeVariablesLib

[Michael Zimmermann]

I'm using this lib on ARM and it generates unaligned access in it's current
state due to the heavy use of pointer casts.
This changes the binary format so all previously saved data will be lost.

diff --git a/OvmfPkg/Library/SerializeVariablesLib/SerializeVariablesLib.c
b/OvmfPkg/Library/SerializeVariablesLib/SerializeVariablesLib.c
index 6822c5c..f6c92c1 100644
--- a/OvmfPkg/Library/SerializeVariablesLib/SerializeVariablesLib.c
+++ b/OvmfPkg/Library/SerializeVariablesLib/SerializeVariablesLib.c
@@ -80,13 +80,13 @@ UnpackVariableFromBuffer (
   }

   *Name = (CHAR16*) (BytePtr + Offset);
-  Offset = Offset + *(UINT32*)BytePtr;
+  Offset = Offset + ALIGN_VALUE(*NameSize, sizeof(UINT32));
   if (Offset > MaxSize) {
     return EFI_INVALID_PARAMETER;
   }

   *Guid = (EFI_GUID*) (BytePtr + Offset);
-  Offset = Offset + sizeof (EFI_GUID);
+  Offset = Offset + ALIGN_VALUE(sizeof (EFI_GUID), sizeof(UINT32));
   if (Offset > MaxSize) {
     return EFI_INVALID_PARAMETER;
   }
@@ -104,7 +104,7 @@ UnpackVariableFromBuffer (
   }

   *Data = (VOID*) (BytePtr + Offset);
-  Offset = Offset + *DataSize;
+  Offset = Offset + ALIGN_VALUE(*DataSize, sizeof(UINT32));
   if (Offset > MaxSize) {
     return EFI_INVALID_PARAMETER;
   }
@@ -284,26 +284,26 @@ IterateVariablesCallbackSetSystemVariable (
   IN  VOID                         *Data
   )
 {
-  EFI_STATUS          Status;
-  STATIC CONST UINT32 AuthMask =
-                        EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS |
-                        EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS;
-
-  Status = gRT->SetVariable (
-             VariableName,
-             VendorGuid,
-             Attributes,
-             DataSize,
-             Data
-             );
-
-  if (Status == EFI_SECURITY_VIOLATION && (Attributes & AuthMask) != 0) {
-    DEBUG ((DEBUG_WARN, "%a: setting authenticated variable \"%s\" "
-            "failed with EFI_SECURITY_VIOLATION, ignoring\n", __FUNCTION__,
-            VariableName));
-    Status = EFI_SUCCESS;
-  }
-  return Status;
+  EFI_STATUS          Status;
+  STATIC CONST UINT32 AuthMask =
+                        EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS |
+                        EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS;
+
+  Status = gRT->SetVariable (
+             VariableName,
+             VendorGuid,
+             Attributes,
+             DataSize,
+             Data
+             );
+
+  if (Status == EFI_SECURITY_VIOLATION && (Attributes & AuthMask) != 0) {
+    DEBUG ((DEBUG_WARN, "%a: setting authenticated variable \"%s\" "
+            "failed with EFI_SECURITY_VIOLATION, ignoring\n", __FUNCTION__,
+            VariableName));
+    Status = EFI_SUCCESS;
+  }
+  return Status;
 }


@@ -366,7 +366,7 @@ AppendToBuffer (
     Size
     );

-  Instance->DataSize = NewSize;
+  Instance->DataSize = ALIGN_VALUE(NewSize, sizeof(UINT32));
 }


@@ -764,12 +764,12 @@ SerializeVariablesAddVariable (
   SerializedNameSize = (UINT32) StrSize (VariableName);

   SerializedSize =
-    sizeof (SerializedNameSize) +
-    SerializedNameSize +
-    sizeof (*VendorGuid) +
-    sizeof (Attributes) +
-    sizeof (SerializedDataSize) +
-    DataSize;
+    ALIGN_VALUE(sizeof (SerializedNameSize), sizeof(UINT32)) +
+    ALIGN_VALUE(SerializedNameSize, sizeof(UINT32)) +
+    ALIGN_VALUE(sizeof (*VendorGuid), sizeof(UINT32)) +
+    ALIGN_VALUE(sizeof (Attributes), sizeof(UINT32)) +
+    ALIGN_VALUE(sizeof (SerializedDataSize), sizeof(UINT32)) +
+    ALIGN_VALUE(DataSize, sizeof(UINT32));

   Status = EnsureExtraBufferSpace (
              Instance,
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