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 (2): kexec_file: Disable at runtime if securelevel has been set bpf: Restrict kernel image access functions when the kernel is locked down 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 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