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Commit bffe1baf authored by Yang Shi's avatar Yang Shi Committed by Catalin Marinas
Browse files

arm64: kasan: instrument user memory access API 



The upstream commit 1771c6e1
("x86/kasan: instrument user memory access API") added KASAN instrument to
x86 user memory access API, so added such instrument to ARM64 too.

Define __copy_to/from_user in C in order to add kasan_check_read/write call,
rename assembly implementation to __arch_copy_to/from_user.

Tested by test_kasan module.

Acked-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarYang Shi <yang.shi@linaro.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 4674fdb9

arch/arm64/include/asm/uaccess.h

+21 −4
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
/*

 * User space memory access functions

 */

#include <linux/kasan-checks.h>

#include <linux/string.h>

#include <linux/thread_info.h>
@@ -256,15 +257,29 @@ do { \ 
		-EFAULT;						\

})



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

extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);

extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n);

extern unsigned long __must_check __arch_copy_to_user(void __user *to, const void *from, unsigned long n);

extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);

extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);



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

{

	kasan_check_write(to, n);

	return  __arch_copy_from_user(to, from, n);

}



static inline unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n)

{

	kasan_check_read(from, n);

	return  __arch_copy_to_user(to, from, n);

}



static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)

{

	kasan_check_write(to, n);



	if (access_ok(VERIFY_READ, from, n))

		n = __copy_from_user(to, from, n);

		n = __arch_copy_from_user(to, from, n);

	else /* security hole - plug it */

		memset(to, 0, n);

	return n;
@@ -272,8 +287,10 @@ static inline unsigned long __must_check copy_from_user(void *to, const void __u 


static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)

{

	kasan_check_read(from, n);



	if (access_ok(VERIFY_WRITE, to, n))

		n = __copy_to_user(to, from, n);

		n = __arch_copy_to_user(to, from, n);

	return n;

}

arch/arm64/kernel/arm64ksyms.c

+2 −2
Original line number Diff line number Diff line
@@ -34,8 +34,8 @@ EXPORT_SYMBOL(copy_page); 
EXPORT_SYMBOL(clear_page);



	/* user mem (segment) */

EXPORT_SYMBOL(__copy_from_user);

EXPORT_SYMBOL(__copy_to_user);

EXPORT_SYMBOL(__arch_copy_from_user);

EXPORT_SYMBOL(__arch_copy_to_user);

EXPORT_SYMBOL(__clear_user);

EXPORT_SYMBOL(__copy_in_user);

arch/arm64/lib/copy_from_user.S

+2 −2
Original line number Diff line number Diff line
@@ -66,7 +66,7 @@ 
	.endm



end	.req	x5

ENTRY(__copy_from_user)

ENTRY(__arch_copy_from_user)

ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_ALT_PAN_NOT_UAO, \

	    CONFIG_ARM64_PAN)

	add	end, x0, x2
@@ -75,7 +75,7 @@ ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_ALT_PAN_NOT_UAO, \ 
	    CONFIG_ARM64_PAN)

	mov	x0, #0				// Nothing to copy

	ret

ENDPROC(__copy_from_user)

ENDPROC(__arch_copy_from_user)



	.section .fixup,"ax"

	.align	2

arch/arm64/lib/copy_to_user.S

+2 −2
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ 
	.endm



end	.req	x5

ENTRY(__copy_to_user)

ENTRY(__arch_copy_to_user)

ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_ALT_PAN_NOT_UAO, \

	    CONFIG_ARM64_PAN)

	add	end, x0, x2
@@ -74,7 +74,7 @@ ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_ALT_PAN_NOT_UAO, \ 
	    CONFIG_ARM64_PAN)

	mov	x0, #0

	ret

ENDPROC(__copy_to_user)

ENDPROC(__arch_copy_to_user)



	.section .fixup,"ax"

	.align	2