StandaloneMmMemLib.c

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#include "StandaloneMmMemLibInternal.h"
 
//
// Maximum support address used to check input buffer
//
EFI_PHYSICAL_ADDRESS  mMmMemLibInternalMaximumSupportAddress = 0;
 
BOOLEAN
EFIAPI
MmIsBufferOutsideMmValid (
  IN EFI_PHYSICAL_ADDRESS  Buffer,
  IN UINT64                Length
  )
{
  //
  // Check override.
  // NOTE: (B:0->L:4G) is invalid for IA32, but (B:1->L:4G-1)/(B:4G-1->L:1) is valid.
  //
  if ((Length > mMmMemLibInternalMaximumSupportAddress) ||
      (Buffer > mMmMemLibInternalMaximumSupportAddress) ||
      ((Length != 0) && (Buffer > (mMmMemLibInternalMaximumSupportAddress - (Length - 1)))))
  {
    //
    // Overflow happen
    //
    DEBUG ((
      DEBUG_ERROR,
      "MmIsBufferOutsideMmValid: Overflow: Buffer (0x%lx) - Length (0x%lx), MaximumSupportAddress (0x%lx)\n",
      Buffer,
      Length,
      mMmMemLibInternalMaximumSupportAddress
      ));
    return FALSE;
  }
 
  return MmMemLibIsValidNonMmramRange (Buffer, Length);
}
 
EFI_STATUS
EFIAPI
MmCopyMemToMmram (
  OUT VOID       *DestinationBuffer,
  IN CONST VOID  *SourceBuffer,
  IN UINTN       Length
  )
{
  if (!MmIsBufferOutsideMmValid ((EFI_PHYSICAL_ADDRESS)(UINTN)SourceBuffer, Length)) {
    DEBUG ((DEBUG_ERROR, "MmCopyMemToMmram: Security Violation: Source (0x%x), Length (0x%x)\n", SourceBuffer, Length));
    return EFI_SECURITY_VIOLATION;
  }
 
  CopyMem (DestinationBuffer, SourceBuffer, Length);
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
MmCopyMemFromMmram (
  OUT VOID       *DestinationBuffer,
  IN CONST VOID  *SourceBuffer,
  IN UINTN       Length
  )
{
  if (!MmIsBufferOutsideMmValid ((EFI_PHYSICAL_ADDRESS)(UINTN)DestinationBuffer, Length)) {
    DEBUG ((
      DEBUG_ERROR,
      "MmCopyMemFromMmram: Security Violation: Destination (0x%x), Length (0x%x)\n",
      DestinationBuffer,
      Length
      ));
    return EFI_SECURITY_VIOLATION;
  }
 
  CopyMem (DestinationBuffer, SourceBuffer, Length);
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
MmCopyMem (
  OUT VOID       *DestinationBuffer,
  IN CONST VOID  *SourceBuffer,
  IN UINTN       Length
  )
{
  if (!MmIsBufferOutsideMmValid ((EFI_PHYSICAL_ADDRESS)(UINTN)DestinationBuffer, Length)) {
    DEBUG ((
      DEBUG_ERROR,
      "MmCopyMem: Security Violation: Destination (0x%x), Length (0x%x)\n",
      DestinationBuffer,
      Length
      ));
    return EFI_SECURITY_VIOLATION;
  }
 
  if (!MmIsBufferOutsideMmValid ((EFI_PHYSICAL_ADDRESS)(UINTN)SourceBuffer, Length)) {
    DEBUG ((DEBUG_ERROR, "MmCopyMem: Security Violation: Source (0x%x), Length (0x%x)\n", SourceBuffer, Length));
    return EFI_SECURITY_VIOLATION;
  }
 
  CopyMem (DestinationBuffer, SourceBuffer, Length);
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
MmSetMem (
  OUT VOID  *Buffer,
  IN UINTN  Length,
  IN UINT8  Value
  )
{
  if (!MmIsBufferOutsideMmValid ((EFI_PHYSICAL_ADDRESS)(UINTN)Buffer, Length)) {
    DEBUG ((DEBUG_ERROR, "MmSetMem: Security Violation: Source (0x%x), Length (0x%x)\n", Buffer, Length));
    return EFI_SECURITY_VIOLATION;
  }
 
  SetMem (Buffer, Length, Value);
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
MemLibConstructor (
  IN EFI_HANDLE           ImageHandle,
  IN EFI_MM_SYSTEM_TABLE  *MmSystemTable
  )
{
  //
  // Calculate and save maximum support address
  //
  MmMemLibCalculateMaximumSupportAddress ();
 
  //
  // Initialize valid non-Mmram Ranges from Resource HOB.
  //
  MmMemLibInitializeValidNonMmramRanges ();
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
MemLibDestructor (
  IN EFI_HANDLE           ImageHandle,
  IN EFI_MM_SYSTEM_TABLE  *MmSystemTable
  )
{
  //
  // Deinitialize cached non-Mmram Ranges.
  //
  MmMemLibFreeValidNonMmramRanges ();
  return EFI_SUCCESS;
}