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Commit 90d74045 authored by Julia Lawall's avatar Julia Lawall Committed by Linus Torvalds
Browse files

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: default avatarJulia Lawall <julia@diku.dk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9e58143d

mm/util.c

+3 −8
Original line number Diff line number Diff line
@@ -225,15 +225,10 @@ char *strndup_user(const char __user *s, long n) 
	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';