scripts/coccinelle/api/memdup_user.cocci

/// Use kmemdup_user rather than duplicating its implementation
/// This is a little bit restricted to reduce false positives
///
// Confidence: High
// Copyright: (C) 2010 Nicolas Palix, DIKU.  GPLv2.
// Copyright: (C) 2010 Julia Lawall, DIKU.  GPLv2.
// Copyright: (C) 2010 Gilles Muller, INRIA/LiP6.  GPLv2.
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options: -no_includes -include_headers

virtual patch

@@
expression from,to,size,flag;
position p;
identifier l1,l2;
@@

-  to = \(kmalloc@p\|kzalloc@p\)(size,flag);
+  to = memdup_user(from,size);
   if (
-      to==NULL
+      IS_ERR(to)
                 || ...) {
   <+... when != goto l1;
-  -ENOMEM
+  PTR_ERR(to)
   ...+>
   }
-  if (copy_from_user(to, from, size) != 0) {
-    <+... when != goto l2;
-    -EFAULT
-    ...+>
-  }