diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 89b5f3bd6694..279471c4e58f 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -106,7 +106,8 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
 		return;
 
 	if (offset != 0)
-		csum = csum_sub(csum, csum_partial(skb->data, offset, 0));
+		csum = csum_sub(csum, csum_partial(skb_transport_header(skb),
+						   offset, 0));
 
 	put_cmsg(msg, SOL_IP, IP_CHECKSUM, sizeof(__wsum), &csum);
 }
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 3563788d064f..f1863136d3e4 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1282,8 +1282,6 @@ int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 			 * of this packet since that is all
 			 * that will be read.
 			 */
-			amount -= sizeof(struct udphdr);
-
 		return put_user(amount, (int __user *)arg);
 	}
 
@@ -1377,7 +1375,7 @@ try_again:
 		*addr_len = sizeof(*sin);
 	}
 	if (inet->cmsg_flags)
-		ip_cmsg_recv_offset(msg, skb, sizeof(struct udphdr));
+		ip_cmsg_recv_offset(msg, skb, sizeof(struct udphdr) + off);
 
 	err = copied;
 	if (flags & MSG_TRUNC)