[Patch net-next] kcm: remove a useless copy_from_user()

[Patch net-next] kcm: remove a useless copy_from_user()

[Cong Wang]

struct kcm_clone only contains fd, and kcm_clone() only
writes this struct, so there is no need to copy it from user.

Cc: Tom Herbert <tom@herbertland.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
 net/kcm/kcmsock.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 31762f7..deca20f 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1707,11 +1707,7 @@ static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		struct kcm_clone info;
 		struct socket *newsock = NULL;
 
-		if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
-			return -EFAULT;
-
 		err = kcm_clone(sock, &info, &newsock);
-
 		if (!err) {
 			if (copy_to_user((void __user *)arg, &info,
 					 sizeof(info))) {
-- 
2.5.5

Re: [Patch net-next] kcm: remove a useless copy_from_user()

[David Miller]

From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Thu, 13 Apr 2017 11:38:02 -0700

> struct kcm_clone only contains fd, and kcm_clone() only
> writes this struct, so there is no need to copy it from user.
> 
> Cc: Tom Herbert <tom@herbertland.com>
> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

Applied.