mm: use memdup_user
Author: 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/)
//
@@
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
- ...+>
- }
//
Signed-off-by: Julia Lawall
Cc: KOSAKI Motohiro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
---
mm/util.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
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 @@ 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'; |
---
mm/util.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
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 @@ 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';