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    SubjectRe: [PATCH 0/6] kexec: A new system call to allow in kernel loading
    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


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