1 files changed, 14 insertions, 5 deletions

diff --git a/kernel/net/ipv4/ip_sockglue.c b/kernel/net/ipv4/ip_sockglue.c
index a50124260..bc14c5bb1 100644
--- a/kernel/net/ipv4/ip_sockglue.c
+++ b/kernel/net/ipv4/ip_sockglue.c
@@ -98,7 +98,7 @@ static void ip_cmsg_recv_retopts(struct msghdr *msg, struct sk_buff *skb)
 }
 
 static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
-				  int offset)
+				  int tlen, int offset)
 {
 	__wsum csum = skb->csum;
 
@@ -106,7 +106,9 @@ 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->data + tlen,
+					     offset, 0));
 
 	put_cmsg(msg, SOL_IP, IP_CHECKSUM, sizeof(__wsum), &csum);
 }
@@ -152,7 +154,7 @@ static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
 }
 
 void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb,
-			 int offset)
+			 int tlen, int offset)
 {
 	struct inet_sock *inet = inet_sk(skb->sk);
 	unsigned int flags = inet->cmsg_flags;
@@ -215,7 +217,7 @@ void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb,
 	}
 
 	if (flags & IP_CMSG_CHECKSUM)
-		ip_cmsg_recv_checksum(msg, skb, offset);
+		ip_cmsg_recv_checksum(msg, skb, tlen, offset);
 }
 EXPORT_SYMBOL(ip_cmsg_recv_offset);
 
@@ -1190,7 +1192,14 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb)
 		pktinfo->ipi_ifindex = 0;
 		pktinfo->ipi_spec_dst.s_addr = 0;
 	}
-	skb_dst_drop(skb);
+	/* We need to keep the dst for __ip_options_echo()
+	 * We could restrict the test to opt.ts_needtime || opt.srr,
+	 * but the following is good enough as IP options are not often used.
+	 */
+	if (unlikely(IPCB(skb)->opt.optlen))
+		skb_dst_force(skb);
+	else
+		skb_dst_drop(skb);
 }
 
 int ip_setsockopt(struct sock *sk, int level,