Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

torvalds · torvalds · commit e7c42a89e9f1 · 2019-03-02T11:47:29.000-08:00
Pull x86 fixes from Thomas Gleixner:
 "Two last minute fixes:

   - Prevent value evaluation via functions happening in the user access
     enabled region of __put_user() (put another way: make sure to
     evaluate the value to be stored in user space _before_ enabling
     user space accesses)

   - Correct the definition of a Hyper-V hypercall constant"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/hyper-v: Fix definition of HV_MAX_FLUSH_REP_COUNT
  x86/uaccess: Don't leak the AC flag into __put_user() value evaluation
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
@@ -841,7 +841,7 @@ union hv_gpa_page_range {
  * count is equal with how many entries of union hv_gpa_page_range can
  * be populated into the input parameter page.
  */
-#define HV_MAX_FLUSH_REP_COUNT (PAGE_SIZE - 2 * sizeof(u64) /	\
+#define HV_MAX_FLUSH_REP_COUNT ((PAGE_SIZE - 2 * sizeof(u64)) /	\
 				sizeof(union hv_gpa_page_range))
 
 struct hv_guest_mapping_flush_list {
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
@@ -284,7 +284,7 @@ do {									\
 		__put_user_goto(x, ptr, "l", "k", "ir", label);		\
 		break;							\
 	case 8:								\
-		__put_user_goto_u64((__typeof__(*ptr))(x), ptr, label);	\
+		__put_user_goto_u64(x, ptr, label);			\
 		break;							\
 	default:							\
 		__put_user_bad();					\
@@ -431,8 +431,10 @@ do {									\
 ({								\
 	__label__ __pu_label;					\
 	int __pu_err = -EFAULT;					\
+	__typeof__(*(ptr)) __pu_val;				\
+	__pu_val = x;						\
 	__uaccess_begin();					\
-	__put_user_size((x), (ptr), (size), __pu_label);	\
+	__put_user_size(__pu_val, (ptr), (size), __pu_label);	\
 	__pu_err = 0;						\
 __pu_label:							\
 	__uaccess_end();					\
