Le 16/03/2021 à 04:17, Jordan Niethe a écrit :
From: Russell Currey <rus...@russell.cc>
To enable strict module RWX on powerpc, set:
CONFIG_STRICT_MODULE_RWX=y
You should also have CONFIG_STRICT_KERNEL_RWX=y set to have any real
security benefit.
ARCH_HAS_STRICT_MODULE_RWX is set to require ARCH_HAS_STRICT_KERNEL_RWX.
This is due to a quirk in arch/Kconfig and arch/powerpc/Kconfig that
makes STRICT_MODULE_RWX *on by default* in configurations where
STRICT_KERNEL_RWX is *unavailable*.
Not that easy on book3s/32. On it, you can't protect memory against execution on a page basis, you
can only do it on a segment basis. So in order to do that, when would need to allocate to areas of
memory: one in module space for text and one in vmalloc space for data.
See https://github.com/linuxppc/linux/commit/6ca05532 and
https://github.com/linuxppc/linux/commit/7fbc22ce
Since this doesn't make much sense, and module RWX without kernel RWX
doesn't make much sense, having the same dependencies as kernel RWX
works around this problem.
Signed-off-by: Russell Currey <rus...@russell.cc>
Signed-off-by: Jordan Niethe <jniet...@gmail.com>
---
arch/powerpc/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 4498a27ac9db..d9cadc4212d0 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -137,6 +137,7 @@ config PPC
select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE
&& PPC_BOOK3S_64
select ARCH_HAS_SET_MEMORY
select ARCH_HAS_STRICT_KERNEL_RWX if ((PPC_BOOK3S_64 || PPC32) &&
!HIBERNATION)
+ select ARCH_HAS_STRICT_MODULE_RWX if ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAS_UACCESS_FLUSHCACHE
select ARCH_HAS_COPY_MC if PPC64
