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uefiefi

UEFI LoadImage from Memory

I am looking at using Bootservices function LoadImage to load a UEFI application image from memory. Function parameters are: 

typedef
EFI_STATUS
LoadImage (
  IN BOOLEAN BootPolicy,
  IN EFI_HANDLE ParentImageHandle,
  IN EFI_DEVICE_PATH_PROTOCOL *DevicePath,
  IN VOID *SourceBuffer OPTIONAL,
  IN UINTN SourceSize,
  OUT EFI_HANDLE *ImageHandle
  );

Where I am allowed to provide a sourcebuffer that is already populated with the PE/COFF image to load. I am currently using sourcebuffer, and have prepopulated the buffer with a valid PE/COFF files contents. I pass that in under SourceBuffer and set DevicePath to Null. I receive the error "EFI_LOAD_ERROR Image was not loaded because the image format was corrupt or not understood."

What am I doing wrong?

Solution

  • You need to provide the information about the memory buffer as a device path - in the DevicePath argument.

    Have a look through chapter 9 Device Path Protocol in the UEFI 2.5 specification (from the UEFI forum). Especially 9.3.2.3 Memory Mapped Device Path.

    You should load the entire file just as is is - no picking apart of sections required.

    For an example, you can have a look at the GRUB arm64 Linux loader, which does just this.