[syslinux] extending ldlinux.sys to ask for a password

[H. Peter Anvin]

Harald Milz wrote:
> Hi,
> 
> the USB boot I was just talking about is a test bed for booting a system
> with all filesystems including root encrypted with cryptsetup-LUKS. I am
> experimenting with various bootloaders to ask for a password. Booting the
> box from the harddisk with GRUB works fine, it requires a little patch for
> grub and the kernel. 
> 
> The mechanism is the bootloader appends the password to the kernel
> command line, and the kernel deletes it again but passes the "unknown"
> parameter to the initramfs environment. So far so good.
> 
> I had a look at the syslinux code to find a proper place to ask for the
> password. The idea is to add a parameter to the APPEND line which, when
> present, makes ldlinux.sys ask for the actual password and append it to the
> kernel command line in runkernel.inc. This should happen after the initial
> and copyright messages. What is a good place to add a small module like
> that, between all_read: and %include "runkernel.inc"? 
> 

The right way to do this is with a COM32 module.

	-hpa