Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

[uclinux-h8/linux.git] / arch / riscv / include / asm / uaccess.h

diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h
index 4297f43..f314ff4 100644 (file)
--- a/arch/riscv/include/asm/uaccess.h
+++ b/arch/riscv/include/asm/uaccess.h
@@ -306,7 +306,9 @@ do {                                                                \
  * data types like structures or arrays.
  *
  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
- * to the result of dereferencing @ptr.
+ * to the result of dereferencing @ptr. The value of @x is copied to avoid
+ * re-ordering where @x is evaluated inside the block that enables user-space
+ * access (thus bypassing user space protection if @x is a function).
  *
  * Caller must check the pointer with access_ok() before calling this
  * function.
@@ -316,12 +318,13 @@ do {                                                              \
 #define __put_user(x, ptr)                                     \
 ({                                                             \
        __typeof__(*(ptr)) __user *__gu_ptr = (ptr);            \
+       __typeof__(*__gu_ptr) __val = (x);                      \
        long __pu_err = 0;                                      \
                                                                \
        __chk_user_ptr(__gu_ptr);                               \
                                                                \
        __enable_user_access();                                 \
-       __put_user_nocheck(x, __gu_ptr, __pu_err);              \
+       __put_user_nocheck(__val, __gu_ptr, __pu_err);          \
        __disable_user_access();                                \
                                                                \
        __pu_err;                                               \