An extracted image is wholly derived from the original archive image.
If the original archive image has been verified and marked as trusted,
then this trust logically extends to any image extracted from it.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Provide image_extract_exec() as a helper method to allow single-member
archive images (such as gzip compressed images) to be executed without
an explicit "imgextract" step.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add the concept of extracting an image from an archive (which could be
a single-file archive such as a gzip-compressed file), along with an
"imgextract" command to expose this functionality to scripts.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
