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Subject[PATCH 05/43] asm: x86: instrument usercopy in get_user() and __put_user_size()
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Use hooks from instrumented.h to notify bug detection tools about
usercopy events in get_user() and put_user_size().

It's still unclear how to instrument put_user(), which assumes that
instrumentation code doesn't clobber RAX.

Signed-off-by: Alexander Potapenko <glider@google.com>
---
Link: https://linux-review.googlesource.com/id/Ia9f12bfe5832623250e20f1859fdf5cc485a2fce
---
arch/x86/include/asm/uaccess.h | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 33a68407def3f..86ad5ab211e97 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -5,6 +5,7 @@
* User space memory access functions
*/
#include <linux/compiler.h>
+#include <linux/instrumented.h>
#include <linux/kasan-checks.h>
#include <linux/string.h>
#include <asm/asm.h>
@@ -126,11 +127,13 @@ extern int __get_user_bad(void);
int __ret_gu; \
register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \
__chk_user_ptr(ptr); \
+ instrument_copy_from_user_before((void *)&(x), ptr, sizeof(*(ptr))); \
asm volatile("call __" #fn "_%P4" \
: "=a" (__ret_gu), "=r" (__val_gu), \
ASM_CALL_CONSTRAINT \
: "0" (ptr), "i" (sizeof(*(ptr)))); \
(x) = (__force __typeof__(*(ptr))) __val_gu; \
+ instrument_copy_from_user_after((void *)&(x), ptr, sizeof(*(ptr)), 0); \
__builtin_expect(__ret_gu, 0); \
})

@@ -275,7 +278,9 @@ extern void __put_user_nocheck_8(void);

#define __put_user_size(x, ptr, size, label) \
do { \
+ __typeof__(*(ptr)) __pus_val = x; \
__chk_user_ptr(ptr); \
+ instrument_copy_to_user(ptr, &(__pus_val), size); \
switch (size) { \
case 1: \
__put_user_goto(x, ptr, "b", "iq", label); \
@@ -313,6 +318,7 @@ do { \
#define __get_user_size(x, ptr, size, label) \
do { \
__chk_user_ptr(ptr); \
+ instrument_copy_from_user_before((void *)&(x), ptr, size); \
switch (size) { \
unsigned char x_u8__; \
case 1: \
@@ -331,6 +337,7 @@ do { \
default: \
(x) = __get_user_bad(); \
} \
+ instrument_copy_from_user_after((void *)&(x), ptr, size, 0); \
} while (0)

#define __get_user_asm(x, addr, itype, ltype, label) \
--
2.34.1.173.g76aa8bc2d0-goog
\
 
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