[patch V4 08/12] uaccess: Provide put/get_user_scoped()

Thomas Gleixner
2025-10-22T12:49:17Z

Provide conveniance wrappers around scoped user access similiar to
put/get_user(), which reduce the usage sites to:

if (!get_user_scoped(val, ptr))
return -EFAULT;

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
V4: Rename to scoped
---
include/linux/uaccess.h | 44 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 44 insertions(+)

--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -825,6 +825,50 @@ for (bool done = false; !done; done = tr
#define scoped_user_rw_access(uptr, elbl) \
scoped_user_rw_access_size(uptr, sizeof(*(uptr)), elbl)

+/**
+ * get_user_scoped - Read user data with scoped access
+ * @val: The variable to store the value read from user memory
+ * @usrc: Pointer to the user space memory to read from
+ *
+ * Return: true if successful, false when faulted
+ */
+#define get_user_scoped(val, usrc) \
+({ \
+ __label__ efault; \
+ typeof(usrc) _tmpsrc = usrc; \
+ bool _ret = true; \
+ \
+ scoped_user_read_access(_tmpsrc, efault) \
+ unsafe_get_user(val, _tmpsrc, efault); \
+ if (0) { \
+ efault: \
+ _ret = false; \
+ } \
+ _ret; \
+})
+
+/**
+ * put_user_scoped - Write to user memory with scoped access
+ * @val: The value to write
+ * @udst: Pointer to the user space memory to write to
+ *
+ * Return: true if successful, false when faulted
+ */
+#define put_user_scoped(val, udst) \
+({ \
+ __label__ efault; \
+ typeof(udst) _tmpdst = udst; \
+ bool _ret = true; \
+ \
+ scoped_user_write_access(_tmpdst, efault) \
+ unsafe_put_user(val, _tmpdst, efault); \
+ if (0) { \
+ efault: \
+ _ret = false; \
+ } \
+ _ret; \
+})
+
#ifdef CONFIG_HARDENED_USERCOPY
void __noreturn usercopy_abort(const char *name, const char *detail,
bool to_user, unsigned long offset,