Hi James, David is low on cycles at the moment, so I'm taking over for this time round. This patchset introduces an optional kernel lockdown feature, intended to strengthen the boundary between UID 0 and the kernel. When enabled and active (by enabling the config option and passing the "lockdown" option on the kernel command line), various pieces of kernel functionality are restricted. Applications that rely on low-level access to either hardware or the kernel may cease working as a result - therefore this should not be enabled without appropriate evaluation beforehand.
The majority of mainstream distributions have been carrying variants of this patchset for many years now, so there's value in providing a unified upstream implementation to reduce the delta. This PR probably doesn't meet every distribution requirement, but gets us much closer to not requiring external patches. This PR is mostly the same as the previous attempt, but with the following changes: 1) The integration between EFI secure boot and the lockdown state has been removed 2) A new CONFIG_KERNEL_LOCK_DOWN_FORCE kconfig option has been added, which will always enable lockdown regardless of the kernel command line 3) The integration with IMA has been dropped for now. Requiring the use of the IMA secure boot policy when lockdown is enabled isn't practical for most distributions at the moment, as there's still not a great deal of infrastructure for shipping packages with appropriate IMA signatures, and it makes it complicated for end users to manage custom IMA policies. The following changes since commit a3b22b9f11d9fbc48b0291ea92259a5a810e9438: Linux 5.0-rc7 (2019-02-17 18:46:40 -0800) are available in the Git repository at: https://github.com/mjg59/linux lock_down for you to fetch changes up to 43e004ecae91bf9159b8e91cd1d613e58b8f63f8: lockdown: Print current->comm in restriction messages (2019-02-28 11:19:23 -0800) ---------------------------------------------------------------- Dave Young (1): Copy secure_boot flag in boot params across kexec reboot David Howells (12): Add the ability to lock down access to the running kernel image Enforce module signatures if the kernel is locked down Prohibit PCMCIA CIS storage when the kernel is locked down Lock down TIOCSSERIAL Lock down module params that specify hardware parameters (eg. ioport) x86/mmiotrace: Lock down the testmmiotrace module Lock down /proc/kcore Lock down kprobes bpf: Restrict kernel image access functions when the kernel is locked down Lock down perf debugfs: Restrict debugfs when the kernel is locked down lockdown: Print current->comm in restriction messages Jiri Bohac (2): kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE kexec_file: Restrict at runtime if the kernel is locked down Josh Boyer (2): 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 lift kernel lockdown 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 (7): Restrict /dev/{mem,kmem,port} when the kernel is locked down kexec_load: 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/msr: Restrict MSR access when the kernel is locked down ACPI: Limit access to custom_method when the kernel is locked down arch/x86/Kconfig | 20 ++++++++++++----- arch/x86/include/asm/setup.h | 2 ++ arch/x86/kernel/ioport.c | 6 ++++-- arch/x86/kernel/kexec-bzimage64.c | 1 + arch/x86/kernel/msr.c | 10 +++++++++ arch/x86/mm/testmmiotrace.c | 3 +++ crypto/asymmetric_keys/verify_pefile.c | 4 +++- 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 | 2 ++ drivers/input/misc/uinput.c | 1 + drivers/pci/pci-sysfs.c | 9 ++++++++ drivers/pci/proc.c | 9 +++++++- drivers/pci/syscall.c | 3 ++- drivers/pcmcia/cistpl.c | 3 +++ drivers/tty/serial/serial_core.c | 6 ++++++ drivers/tty/sysrq.c | 19 +++++++++++------ fs/debugfs/file.c | 28 ++++++++++++++++++++++++ fs/debugfs/inode.c | 30 ++++++++++++++++++++++++-- fs/proc/kcore.c | 2 ++ include/linux/ima.h | 6 ++++++ include/linux/input.h | 5 +++++ include/linux/kernel.h | 17 +++++++++++++++ include/linux/kexec.h | 4 ++-- include/linux/security.h | 9 +++++++- include/linux/sysrq.h | 8 ++++++- kernel/bpf/syscall.c | 3 +++ kernel/debug/kdb/kdb_main.c | 2 +- kernel/events/core.c | 5 +++++ kernel/kexec.c | 7 ++++++ kernel/kexec_file.c | 56 ++++++++++++++++++++++++++++++++++++++++++------ kernel/kprobes.c | 3 +++ kernel/module.c | 56 ++++++++++++++++++++++++++++++++++++------------ kernel/params.c | 26 ++++++++++++++++++----- kernel/power/hibernate.c | 2 +- kernel/power/user.c | 3 +++ security/Kconfig | 24 +++++++++++++++++++++ security/Makefile | 3 +++ security/lock_down.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 41 files changed, 466 insertions(+), 50 deletions(-) create mode 100644 security/lock_down.c
