mm: use memdup_user
Use memdup_user when user data is immediately copied into the
allocated region.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
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
- ...+>
- }
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/util.c b/mm/util.c
index f5712e8..4735ea4 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -225,15 +225,10 @@
if (length > n)
return ERR_PTR(-EINVAL);
- p = kmalloc(length, GFP_KERNEL);
+ p = memdup_user(s, length);
- if (!p)
- return ERR_PTR(-ENOMEM);
-
- if (copy_from_user(p, s, length)) {
- kfree(p);
- return ERR_PTR(-EFAULT);
- }
+ if (IS_ERR(p))
+ return p;
p[length - 1] = '\0';
