On Wed, Nov 20, 2013 at 12:50:45PM -0500, Vivek Goyal wrote: > Current proposed secureboot implementation disables kexec/kdump because > it can allow unsigned kernel to run on a secureboot platform. Intial > idea was to sign /sbin/kexec binary and let that binary do the kernel > signature verification. I had posted RFC patches for this apparoach > here. > > https://lkml.org/lkml/2013/9/10/560 > > Later we had discussion at Plumbers and most of the people thought > that signing and trusting /sbin/kexec is becoming complex. So a > better idea might be let kernel do the signature verification of > new kernel being loaded. This calls for implementing a new system call > and moving lot of user space code in kernel. > > kexec_load() system call allows loading a kexec/kdump kernel and jump > to that kernel at right time. Though a lot of processing is done in > user space which prepares a list of segments/buffers to be loaded and > kexec_load() works on that list of segments. It does not know what's > contained in those segments. > > Now a new system call kexec_file_load() is implemented which takes > kernel fd and initrd fd as parameters. Now kernel should be able > to verify signature of newly loaded kernel. > > This is an early RFC patchset. I have not done signature handling > part yet. This is more of a minimal patch to show how new system > call and functionality will look like. Right now it can only handle > bzImage with 64bit entry point on x86_64. No EFI, no x86_32 or any > other architecture. Rest of the things can be added slowly as need > arises. In first iteration, I have tried to address most common use case > for us. Very good stuff, thanks for working on this. How have you been testing this on the userspace side? Are there patches to kexec, or are you just using a small test program with the new syscall? I'll comment on the patches separately. greg k-h
