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Commit 49f10dde authored by Kees Cook's avatar Kees Cook Committed by Alex Shi
Browse files

ARM: uaccess: Enable hardened usercopy 



Enables CONFIG_HARDENED_USERCOPY checks on arm.

Based on code from PaX and grsecurity.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
(cherry picked from commit dfd45b6103c973bfcea2341d89e36faf947dbc33)
Signed-off-by: default avatarAlex Shi <alex.shi@linaro.org>
parent 4f80bcbe

arch/arm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ config ARM 
	select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6

	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32

	select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32

	select HAVE_ARCH_HARDENED_USERCOPY

	select HAVE_ARCH_SECCOMP_FILTER if (AEABI && !OABI_COMPAT)

	select HAVE_ARCH_TRACEHOOK

	select HAVE_BPF_JIT

arch/arm/include/asm/uaccess.h

+9 −2
Original line number Diff line number Diff line
@@ -496,7 +496,10 @@ arm_copy_from_user(void *to, const void __user *from, unsigned long n); 
static inline unsigned long __must_check

__copy_from_user(void *to, const void __user *from, unsigned long n)

{

	unsigned int __ua_flags = uaccess_save_and_enable();

	unsigned int __ua_flags;



	check_object_size(to, n, false);

	__ua_flags = uaccess_save_and_enable();

	n = arm_copy_from_user(to, from, n);

	uaccess_restore(__ua_flags);

	return n;
@@ -511,11 +514,15 @@ static inline unsigned long __must_check 
__copy_to_user(void __user *to, const void *from, unsigned long n)

{

#ifndef CONFIG_UACCESS_WITH_MEMCPY

	unsigned int __ua_flags = uaccess_save_and_enable();

	unsigned int __ua_flags;



	check_object_size(from, n, true);

	__ua_flags = uaccess_save_and_enable();

	n = arm_copy_to_user(to, from, n);

	uaccess_restore(__ua_flags);

	return n;

#else

	check_object_size(from, n, true);

	return arm_copy_to_user(to, from, n);

#endif

}