From c35717c71e983ed55d61e523cbd11a798429bc82 Mon Sep 17 00:00:00 2001 From: Russell Currey Date: Wed, 9 Jun 2021 11:34:29 +1000 Subject: [PATCH] powerpc: Set ARCH_HAS_STRICT_MODULE_RWX 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*. 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. Book3s/32 603 and 604 core processors are not able to write protect kernel pages so do not set ARCH_HAS_STRICT_MODULE_RWX for Book3s/32. [jpn: - predicate on !PPC_BOOK3S_604 - make module_alloc() use PAGE_KERNEL protection] Signed-off-by: Russell Currey Signed-off-by: Jordan Niethe Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210609013431.9805-8-jniethe5@gmail.com --- arch/powerpc/Kconfig | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index abfe2e9225fa..72f307f1796b 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -142,6 +142,7 @@ 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 && !PPC_BOOK3S_32 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_HAS_UACCESS_FLUSHCACHE select ARCH_HAS_UBSAN_SANITIZE_ALL @@ -267,6 +268,7 @@ config PPC select PPC_DAWR if PPC64 select RTC_LIB select SPARSE_IRQ + select STRICT_KERNEL_RWX if STRICT_MODULE_RWX select SYSCTL_EXCEPTION_TRACE select THREAD_INFO_IN_TASK select VIRT_TO_BUS if !PPC64