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Subject[PATCH 2/27] drivers/net: Use memdup_user
From: Julia Lawall <julia@diku.dk>

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>

---
drivers/net/ppp_generic.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 5441688..da7943d 100644
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -539,14 +539,9 @@ static int get_filter(void __user *arg, struct sock_filter **p)
}

len = uprog.len * sizeof(struct sock_filter);
- code = kmalloc(len, GFP_KERNEL);
- if (code == NULL)
- return -ENOMEM;
-
- if (copy_from_user(code, uprog.filter, len)) {
- kfree(code);
- return -EFAULT;
- }
+ code = memdup_user(uprog.filter, len);
+ if (IS_ERR(code))
+ return PTR_ERR(code);

err = sk_chk_filter(code, uprog.len);
if (err) {

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