From: WANG Cong <xiyou.wangcong@gmail.com>
Date: Thu, 13 Apr 2017 18:38:02 +0000 (-0700)
Subject: kcm: remove a useless copy_from_user()
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=f5001ceab8996d76880004381c188b3b96c8c7af;p=openwrt%2Fstaging%2Fblogic.git

kcm: remove a useless copy_from_user()

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 31762f76cdb5..deca20fb2ce2 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))) {