Extend the ValidateFvHeader function, additionally to the header checks
walk over the list of variables and sanity check them.
In case we find inconsistencies indicating variable store corruption
return EFI_NOT_FOUND so the variable store will be re-initialized.
Signed-off-by: Gerd Hoffmann <kra...@redhat.com>
---
OvmfPkg/VirtNorFlashDxe/VirtNorFlashFvb.c | 82 +++++++++++++++++++++--
1 file changed, 77 insertions(+), 5 deletions(-)
diff --git a/OvmfPkg/VirtNorFlashDxe/VirtNorFlashFvb.c
b/OvmfPkg/VirtNorFlashDxe/VirtNorFlashFvb.c
index 5ee98e9b595a..72a197e5aa20 100644
--- a/OvmfPkg/VirtNorFlashDxe/VirtNorFlashFvb.c
+++ b/OvmfPkg/VirtNorFlashDxe/VirtNorFlashFvb.c
@@ -185,11 +185,16 @@ ValidateFvHeader (
IN NOR_FLASH_INSTANCE *Instance
)
{
- UINT16 Checksum;
- EFI_FIRMWARE_VOLUME_HEADER *FwVolHeader;
- VARIABLE_STORE_HEADER *VariableStoreHeader;
- UINTN VariableStoreLength;
- UINTN FvLength;
+ UINT16 Checksum;
+ EFI_FIRMWARE_VOLUME_HEADER *FwVolHeader;
+ VARIABLE_STORE_HEADER *VariableStoreHeader;
+ UINTN VarOffset;
+ AUTHENTICATED_VARIABLE_HEADER *VarHeader;
+ UINTN VarSize;
+ CHAR16 *VarName;
+ CHAR8 *VarState;
+ UINTN VariableStoreLength;
+ UINTN FvLength;
FwVolHeader = (EFI_FIRMWARE_VOLUME_HEADER *)Instance->RegionBaseAddress;
@@ -260,6 +265,73 @@ ValidateFvHeader (
return EFI_NOT_FOUND;
}
+ // check variables
+ DEBUG ((DEBUG_INFO, "%a: checking variables\n", __func__));
+ VarOffset = sizeof (*VariableStoreHeader);
+ while (VarOffset + sizeof (*VarHeader) < VariableStoreHeader->Size) {
+ VarHeader = (VOID *)((UINTN)VariableStoreHeader + VarOffset);
+ if (VarHeader->StartId != 0x55aa) {
+ DEBUG ((DEBUG_INFO, "%a: end of var list\n", __func__));
+ break;
+ }
+
+ VarSize = sizeof (*VarHeader) + VarHeader->NameSize + VarHeader->DataSize;
+ if (VarOffset + VarSize > VariableStoreHeader->Size) {
+ DEBUG ((
+ DEBUG_ERROR,
+ "%a: invalid variable size: 0x%x + 0x%x + 0x%x + 0x%x > 0x%x\n",
+ __func__,
+ VarOffset,
+ sizeof (*VarHeader),
+ VarHeader->NameSize,
+ VarHeader->DataSize,
+ VariableStoreHeader->Size
+ ));
+ return EFI_NOT_FOUND;
+ }
+
+ VarName = (VOID *)((UINTN)VariableStoreHeader + VarOffset
+ + sizeof (*VarHeader));
+ switch (VarHeader->State) {
+ case VAR_HEADER_VALID_ONLY:
+ VarState = "header-ok";
+ VarName = L"<unknown>";
+ break;
+ case VAR_ADDED:
+ VarState = "ok";
+ break;
+ case VAR_ADDED &VAR_IN_DELETED_TRANSITION:
+ VarState = "del-in-transition";
+ break;
+ case VAR_ADDED &VAR_DELETED:
+ case VAR_ADDED &VAR_DELETED &VAR_IN_DELETED_TRANSITION:
+ VarState = "deleted";
+ break;
+ default:
+ DEBUG ((
+ DEBUG_ERROR,
+ "%a: invalid variable state: 0x%x\n",
+ __func__,
+ VarState
+ ));
+ return EFI_NOT_FOUND;
+ }
+
+ DEBUG ((
+ DEBUG_VERBOSE,
+ "%a: +0x%04x: name=0x%x data=0x%x '%s' (%a)\n",
+ __func__,
+ VarOffset,
+ VarHeader->NameSize,
+ VarHeader->DataSize,
+ VarName,
+ VarState
+ ));
+
+ VarSize = (VarSize + 3) & ~3; // align
+ VarOffset += VarSize;
+ }
+
return EFI_SUCCESS;
}
--
2.43.0
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