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SubjectRe: [PATCH 0/6] kexec: A new system call to allow in kernel loading
Tested kdump and kexec using --use-kexec2-syscall on kenrel 3.13.0-rc2+,
they work very well.


On 11/20/13 at 12:50pm, 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.
>
> Any feedback is welcome.
>
> Vivek Goyal (6):
> kexec: Export vmcoreinfo note size properly
> kexec: Move segment verification code in a separate function
> resource: Provide new functions to walk through resources
> kexec: A new system call, kexec_file_load, for in kernel kexec
> kexec-bzImage: Support for loading bzImage using 64bit entry
> kexec: Support for Kexec on panic using new system call
>
> arch/x86/include/asm/crash.h | 9 +
> arch/x86/include/asm/kexec-bzimage.h | 12 +
> arch/x86/include/asm/kexec.h | 43 ++
> arch/x86/kernel/Makefile | 2 +
> arch/x86/kernel/crash.c | 585 +++++++++++++++++++++++++++
> arch/x86/kernel/kexec-bzimage.c | 420 +++++++++++++++++++
> arch/x86/kernel/machine_kexec_64.c | 60 +++-
> arch/x86/kernel/purgatory_entry_64.S | 119 ++++++
> arch/x86/syscalls/syscall_64.tbl | 1 +
> include/linux/ioport.h | 6 +
> include/linux/kexec.h | 57 +++
> include/linux/syscalls.h | 3 +
> include/uapi/linux/kexec.h | 4 +
> kernel/kexec.c | 731 ++++++++++++++++++++++++++++++----
> kernel/ksysfs.c | 2 +-
> kernel/resource.c | 108 +++++-
> kernel/sys_ni.c | 1 +
> 17 files changed, 2074 insertions(+), 89 deletions(-)
> create mode 100644 arch/x86/include/asm/crash.h
> create mode 100644 arch/x86/include/asm/kexec-bzimage.h
> create mode 100644 arch/x86/kernel/kexec-bzimage.c
> create mode 100644 arch/x86/kernel/purgatory_entry_64.S
>
> --
> 1.7.7.6
>
>
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec


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