Hi Will & Catalin,

Any comment for this patch?

Thanks, Yang

On 5/27/2016 2:01 PM, Yang Shi wrote:

The upstream commit 1771c6e1a567ea0ba2cccc0a4ffe68a1419fd8ef ("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.

Signed-off-by: Yang Shi yang.shi@linaro.org

v2: Adopted the comment from Andrey and Mark to add kasan_check_read/write into __copy_to/from_user.

arch/arm64/include/asm/uaccess.h | 25 +++++++++++++++++++++---- arch/arm64/kernel/arm64ksyms.c | 4 ++-- arch/arm64/lib/copy_from_user.S | 4 ++-- arch/arm64/lib/copy_to_user.S | 4 ++-- 4 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 0685d74..4dc9a8f 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -23,6 +23,7 @@ */ #include <linux/string.h> #include <linux/thread_info.h> +#include <linux/kasan-checks.h>

#include <asm/alternative.h> #include <asm/cpufeature.h> @@ -269,15 +270,29 @@ 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;

@@ -285,8 +300,10 @@ 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;

}

diff --git a/arch/arm64/kernel/arm64ksyms.c b/arch/arm64/kernel/arm64ksyms.c index 678f30b0..2dc4440 100644 --- a/arch/arm64/kernel/arm64ksyms.c +++ b/arch/arm64/kernel/arm64ksyms.c @@ -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);

diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S index 17e8306..0b90497 100644 --- a/arch/arm64/lib/copy_from_user.S +++ b/arch/arm64/lib/copy_from_user.S @@ -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 diff --git a/arch/arm64/lib/copy_to_user.S b/arch/arm64/lib/copy_to_user.S index 21faae6..7a7efe2 100644 --- a/arch/arm64/lib/copy_to_user.S +++ b/arch/arm64/lib/copy_to_user.S @@ -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