[efi-boot-shim.git] / README

shim is a trivial EFI application that, when run, attempts to open and
execute another application. It will initially attempt to do this via the
standard EFI LoadImage() and StartImage() calls. If these fail (because secure
boot is enabled and the binary is not signed with an appropriate key, for
instance) it will then validate the binary against a built-in certificate. If
this succeeds and if the binary or signing key are not blacklisted then shim
will relocate and execute the binary.

shim will also install a protocol which permits the second-stage bootloader
to perform similar binary validation. This protocol has a GUID as described
in the shim.h header file and provides a single entry point. On 64-bit systems
this entry point expects to be called with SysV ABI rather than MSABI, and
so calls to it should not be wrapped.

To use shim, simply place a DER-encoded public certificate in a file such as
pub.cer and build with "make VENDOR_CERT_FILE=pub.cer".
Commit	Line	Data
bbfd2ab1 MTL	1	shim is a trivial EFI application that, when run, attempts to open and
	2	execute another application. It will initially attempt to do this via the
	3	standard EFI LoadImage() and StartImage() calls. If these fail (because secure
	4	boot is enabled and the binary is not signed with an appropriate key, for
	5	instance) it will then validate the binary against a built-in certificate. If
	6	this succeeds and if the binary or signing key are not blacklisted then shim
	7	will relocate and execute the binary.
	8
	9	shim will also install a protocol which permits the second-stage bootloader
	10	to perform similar binary validation. This protocol has a GUID as described
	11	in the shim.h header file and provides a single entry point. On 64-bit systems
	12	this entry point expects to be called with SysV ABI rather than MSABI, and
	13	so calls to it should not be wrapped.
	14
	15	To use shim, simply place a DER-encoded public certificate in a file such as
	16	pub.cer and build with "make VENDOR_CERT_FILE=pub.cer".