From 43727da90ec8955f1351ad582c6bc8f1c1ab8ab8 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 13 May 2017 18:22:53 -0400
Subject: [PATCH] do_ipv6_setsockopt(): don't open-code memdup_user()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 net/ipv6/ipv6_sockglue.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index a531ba032b85..f8298c9a3160 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -735,14 +735,9 @@ done:
 			retv = -ENOBUFS;
 			break;
 		}
-		gsf = kmalloc(optlen, GFP_KERNEL);
-		if (!gsf) {
-			retv = -ENOBUFS;
-			break;
-		}
-		retv = -EFAULT;
-		if (copy_from_user(gsf, optval, optlen)) {
-			kfree(gsf);
+		gsf = memdup_user(optval, optlen);
+		if (IS_ERR(gsf)) {
+			retv = PTR_ERR(gsf);
 			break;
 		}
 		/* numsrc >= (4G-140)/128 overflow in 32 bits */