On Sat, Mar 28, 2020 at 10:25:47PM +0100, Alexey Gladkov wrote:

On Sat, Mar 28, 2020 at 01:41:02PM -0700, Kees Cook wrote:
 > diff --git a/include/uapi/linux/proc_fs.h b/include/uapi/linux/proc_fs.h

quoted

quoted

new file mode 100644
index 000000000000..dc6d717aa6ec

--- /dev/null
+++ b/include/uapi/linux/proc_fs.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_PROC_FS_H
+#define _UAPI_PROC_FS_H
+
+/* definitions for hide_pid field */
+enum {
+	HIDEPID_OFF            = 0,
+	HIDEPID_NO_ACCESS      = 1,
+	HIDEPID_INVISIBLE      = 2,
+	HIDEPID_NOT_PTRACEABLE = 4,
+};
+
+#endif

-- 
2.25.2

Should the numeric values still be UAPI if there is string parsing now?

I think yes, because these are still valid hidepid= values.

But if we don't expose the values, we can do whatever we like with
future numbers (e.g. the "is this a value or a bit field?" question).

-- 
Kees Cook