On Wednesday, July 13, 2016 3:45:41 PM CEST Thiago Jung Bauermann wrote: > Am Mittwoch, 13 Juli 2016, 15:13:42 schrieb Arnd Bergmann: > > On Wednesday, July 13, 2016 10:41:28 AM CEST Mark Rutland wrote: > > > On Wed, Jul 13, 2016 at 10:01:33AM +0200, Arnd Bergmann wrote: > > > > - kboot/petitboot with all of the user space being part of the trusted > > > > boot> > > > > > chain: it would be good to allow these to modify the dtb as needed > > > > without breaking the trust chain, just like we allow grub or u-boot > > > > to modify the dtb before passing it to the kernel. > > > > > > It depends on *what* we need to modify here. We can modify the bootargs > > > and initrd properties as part of the kexec_file_load syscall, so what > > > else would we want to alter? > > > > I guess petitboot can also just use kexec_load() instead of > > kexec_file_load(), as long as the initramfs containing petitboot is > > trusted by the kernel. > > For secure boot, Petitboot needs to use kexec_file_load, because of the > following two features which the system call enables: > > 1. only allow loading of signed kernels. > 2. "measure" (i.e., record the hashes of) the kernel, initrd, kernel > command line and other boot inputs for the Integrity Measurement > Architecture subsystem. > > Those can't be done with kexec_load. Can't petitboot do both of these in user space? Arnd
