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ARM: uaccess: Enable hardened usercopy 

Enables CONFIG_HARDENED_USERCOPY checks on arm.

Based on code from PaX and grsecurity.

Signed-off-by: Kees Cook <keescook@chromium.org>
hifive-unleashed-5.1
Kees Cook 2016-06-23 15:06:53 -07:00
parent 5b710f34e1
commit dfd45b6103
2 changed files with 10 additions and 2 deletions
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1
arch/arm/Kconfig
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@ -35,6 +35,7 @@ config ARM
select HARDIRQS_SW_RESEND
select HAVE_ARCH_AUDITSYSCALL if (AEABI && !OABI_COMPAT)
select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6
select HAVE_ARCH_HARDENED_USERCOPY
select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU
select HAVE_ARCH_MMAP_RND_BITS if MMU

11
arch/arm/include/asm/uaccess.h
View File

@ -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
}