[PATCH 00/24] Kernel lockdown

David Howells dhowells at redhat.com
Wed Apr 5 17:09:54 UTC 2017


These patches provide a facility by which a variety of avenues by which
userspace can feasibly modify the running kernel image can be locked down.
These include:

 (*) No unsigned modules and no modules for which can't validate the
     signature.

 (*) No use of ioperm(), iopl() and no writing to /dev/port.

 (*) No writing to /dev/mem or /dev/kmem.

 (*) No hibernation.

 (*) Restrict PCI BAR access.

 (*) Restrict MSR access.

 (*) No kexec_load().

 (*) Certain ACPI restrictions.

 (*) Restrict debugfs interface to ASUS WMI.

The lock-down can be configured to be triggered by the EFI secure boot
status, provided the shim isn't insecure.  The lock-down can be lifted by
typing SysRq+x on a keyboard attached to the system.


The patches can be found here also:

	http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=efi-lockdown

They are dependent on the hwparam branch, which I posted separately.

David
---
Chun-Yi Lee (1):
      kexec_file: Disable at runtime if securelevel has been set

Dave Young (1):
      Copy secure_boot flag in boot params across kexec reboot

David Howells (7):
      Add the ability to lock down access to the running kernel image
      efi: Lock down the kernel if booted in secure boot mode
      Enforce module signatures if the kernel is locked down
      scsi: Lock down the eata driver
      Prohibit PCMCIA CIS storage when the kernel is locked down
      Lock down TIOCSSERIAL
      Lock down module params that specify hardware parameters (eg. ioport)

Josh Boyer (3):
      efi: Add EFI_SECURE_BOOT bit
      hibernate: Disable when the kernel is locked down
      acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down

Kyle McMartin (1):
      Add a sysrq option to exit secure boot mode

Lee, Chun-Yi (1):
      bpf: Restrict kernel image access functions when the kernel is locked down

Linn Crosetto (2):
      acpi: Disable ACPI table override if the kernel is locked down
      acpi: Disable APEI error injection if the kernel is locked down

Matthew Garrett (8):
      Restrict /dev/mem and /dev/kmem when the kernel is locked down
      kexec: Disable at runtime if the kernel is locked down
      uswsusp: Disable when the kernel is locked down
      PCI: Lock down BAR access when the kernel is locked down
      x86: Lock down IO port access when the kernel is locked down
      x86: Restrict MSR access when the kernel is locked down
      asus-wmi: Restrict debugfs interface when the kernel is locked down
      ACPI: Limit access to custom_method when the kernel is locked down


 arch/x86/Kconfig                  |   22 ++++++++++++++++++++
 arch/x86/kernel/ioport.c          |    4 ++--
 arch/x86/kernel/kexec-bzimage64.c |    1 +
 arch/x86/kernel/msr.c             |    7 ++++++
 arch/x86/kernel/setup.c           |   40 ++++++++++++++++++++++++++++++++++++-
 drivers/acpi/apei/einj.c          |    3 +++
 drivers/acpi/custom_method.c      |    3 +++
 drivers/acpi/osl.c                |    2 +-
 drivers/acpi/tables.c             |    5 +++++
 drivers/char/mem.c                |    8 +++++++
 drivers/input/misc/uinput.c       |    1 +
 drivers/pci/pci-sysfs.c           |    9 ++++++++
 drivers/pci/proc.c                |    8 ++++++-
 drivers/pci/syscall.c             |    2 +-
 drivers/pcmcia/cistpl.c           |    5 +++++
 drivers/platform/x86/asus-wmi.c   |    9 ++++++++
 drivers/scsi/eata.c               |    7 ++++++
 drivers/tty/serial/serial_core.c  |    6 ++++++
 drivers/tty/sysrq.c               |   19 ++++++++++++------
 include/linux/efi.h               |    1 +
 include/linux/input.h             |    5 +++++
 include/linux/kernel.h            |    9 ++++++++
 include/linux/security.h          |   11 ++++++++++
 include/linux/sysrq.h             |    8 ++++++-
 kernel/debug/kdb/kdb_main.c       |    2 +-
 kernel/kexec.c                    |    7 ++++++
 kernel/kexec_file.c               |    6 ++++++
 kernel/module.c                   |    2 +-
 kernel/params.c                   |   27 ++++++++++++++++++++-----
 kernel/power/hibernate.c          |    2 +-
 kernel/power/user.c               |    3 +++
 kernel/trace/bpf_trace.c          |   11 ++++++++++
 security/Kconfig                  |   15 ++++++++++++++
 security/Makefile                 |    3 +++
 security/lock_down.c              |   40 +++++++++++++++++++++++++++++++++++++
 35 files changed, 291 insertions(+), 22 deletions(-)
 create mode 100644 security/lock_down.c

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