Re: [PATCH v5 0/9] Support strict kernel memory permissions for security

From: Palmer Dabbelt
Date: Mon Apr 20 2020 - 14:27:45 EST


On Wed, 08 Apr 2020 00:56:55 PDT (-0700), zong.li@xxxxxxxxxx wrote:
The main purpose of this patch series is changing the kernel mapping permission
, make sure that code is not writeable, data is not executable, and read-only
data is neither writable nor executable.

This patch series also supports the relevant implementations such as
ARCH_HAS_SET_MEMORY, ARCH_HAS_SET_DIRECT_MAP,
ARCH_SUPPORTS_DEBUG_PAGEALLOC and DEBUG_WX.

Changes in v5:
- Add lockdep_assert_held and more comments for text_mutex.

Changes in v4:
- Use NOKPROBE_SYMBOL instead of __kprobe annotation
- Use text_mutex instead of patch_lock
- Remove 'riscv_' prefix of function name

Changes in v3:
- Fix build error on nommu configuration. We already support nommu on
RISC-V, so we should consider nommu case and test not only rv32/64,
but also nommu.

Changes in v2:
- Use _data to specify the start of data section with write permission.
- Change ftrace patch text implementaion.
- Separate DEBUG_WX patch to another patchset.

Zong Li (9):
riscv: add macro to get instruction length
riscv: introduce interfaces to patch kernel code
riscv: patch code by fixmap mapping
riscv: add ARCH_HAS_SET_MEMORY support
riscv: add ARCH_HAS_SET_DIRECT_MAP support
riscv: add ARCH_SUPPORTS_DEBUG_PAGEALLOC support
riscv: move exception table immediately after RO_DATA
riscv: add alignment for text, rodata and data sections
riscv: add STRICT_KERNEL_RWX support

arch/riscv/Kconfig | 6 +
arch/riscv/include/asm/bug.h | 8 ++
arch/riscv/include/asm/fixmap.h | 2 +
arch/riscv/include/asm/patch.h | 12 ++
arch/riscv/include/asm/set_memory.h | 48 +++++++
arch/riscv/kernel/Makefile | 4 +-
arch/riscv/kernel/ftrace.c | 26 ++--
arch/riscv/kernel/patch.c | 128 +++++++++++++++++++
arch/riscv/kernel/traps.c | 3 +-
arch/riscv/kernel/vmlinux.lds.S | 11 +-
arch/riscv/mm/Makefile | 2 +-
arch/riscv/mm/init.c | 44 +++++++
arch/riscv/mm/pageattr.c | 187 ++++++++++++++++++++++++++++
13 files changed, 466 insertions(+), 15 deletions(-)
create mode 100644 arch/riscv/include/asm/patch.h
create mode 100644 arch/riscv/include/asm/set_memory.h
create mode 100644 arch/riscv/kernel/patch.c
create mode 100644 arch/riscv/mm/pageattr.c

Looks like there are quite a few conflicts here. Do you mind re-spinning the
patch set for me? It's a bit early to spin off for-next right now so there
might be some more conflicts, but hopefully not too many.

Thanks!