Messages in this thread Patch in this message | | | Date | Tue, 6 Mar 2018 20:22:41 +0900 | From | Jinbum Park <> | Subject | [PATCH] arm: mm: Kconfig: Disable KUSER_HELPERS in ARMv6 or later as default |
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Codes for KUSER_HELPERS can be abused as ROP gadaget, So that It's better to disable that as if possible.
Since over ARMv6 has ldrex/strex at user-space, NEED_KUSER_HELPERS is not selected for over ARMv6.
But, Even though NEED_KUSER_HELPERS is not selected, current configuration enable KUSER_HELPERS as default.
* as-is
- Enable KUSER_HELPERS as default even though over ARMv6. - User can disable KUSER_HELPERS.
* to-be
- Disable KUSER_HELPERS in ARMv6 or later as default. - User can enable KUSER_HELPERS for compatibility.
This change removes the unnecessary configuration that has security-risk.
Signed-off-by: Jinbum Park <jinb.park7@gmail.com> --- arch/arm/mm/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig index 7f14acf..40e5fe5 100644 --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -840,7 +840,7 @@ config NEED_KUSER_HELPERS config KUSER_HELPERS bool "Enable kuser helpers in vector page" if !NEED_KUSER_HELPERS depends on MMU - default y + default y if NEED_KUSER_HELPERS help Warning: disabling this option may break user programs. -- 1.9.1
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