[PATCH V14 5/7] driver-core: Introduce BIN_ATTR_ADMIN_{RO,RW}

[ira . weiny]

From: Ira Weiny <ira.weiny@xxxxxxxxx>

Many binary attributes need to limit access to CAP_SYS_ADMIN only; ie
many binary attributes specify is_visible with 0400 or 0600.

Make setting the permissions of such attributes more explicit by
defining BIN_ATTR_ADMIN_{RO,RW}.

Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Suggested-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Suggested-by: Krzysztof Wilczyński <kw@xxxxxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>

---
Changes from V12:
	Pick up review tag
	Bjorn:
		NOTE: this has a lot of similarities to
		https://lore.kernel.org/all/20210416205856.3234481-7-kw@xxxxxxxxx/
		I'm not sure why that patch was not picked up.  But I've
		added Krzysztof as a suggested by if that is ok?

Changes from V11:
	New Patch
---
 include/linux/sysfs.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index e3f1e8ac1f85..fd3fe5c8c17f 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -235,6 +235,22 @@ struct bin_attribute bin_attr_##_name = __BIN_ATTR_WO(_name, _size)
 #define BIN_ATTR_RW(_name, _size)					\
 struct bin_attribute bin_attr_##_name = __BIN_ATTR_RW(_name, _size)
 
+
+#define __BIN_ATTR_ADMIN_RO(_name, _size) {					\
+	.attr	= { .name = __stringify(_name), .mode = 0400 },		\
+	.read	= _name##_read,						\
+	.size	= _size,						\
+}
+
+#define __BIN_ATTR_ADMIN_RW(_name, _size)					\
+	__BIN_ATTR(_name, 0600, _name##_read, _name##_write, _size)
+
+#define BIN_ATTR_ADMIN_RO(_name, _size)					\
+struct bin_attribute bin_attr_##_name = __BIN_ATTR_ADMIN_RO(_name, _size)
+
+#define BIN_ATTR_ADMIN_RW(_name, _size)					\
+struct bin_attribute bin_attr_##_name = __BIN_ATTR_ADMIN_RW(_name, _size)
+
 struct sysfs_ops {
 	ssize_t	(*show)(struct kobject *, struct attribute *, char *);
 	ssize_t	(*store)(struct kobject *, struct attribute *, const char *, size_t);
-- 
2.35.3