Subject: [PATCH 12/24] ipv4: recompile ip options in ipv4_link_failure

From: Stephen Suryaputra <[email-masked]>
Date: Fri, 12 Apr 2019 16:19:27 -0400

[ Upstream commit ed0de45a1008991fdaa27a0152befcb74d126a8b ]

Recompile IP options since IPCB may not be valid anymore when
ipv4_link_failure is called from arp_error_report.

Refer to the commit 3da1ed7ac398 ("net: avoid use IPCB in cipso_v4_error")
and the commit before that (9ef6b42ad6fd) for a similar issue.

Signed-off-by: Stephen Suryaputra <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/ipv4/route.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 7a556e459375..444e0d0aa20b 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1188,8 +1188,16 @@ static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
 static void ipv4_link_failure(struct sk_buff *skb)
 {
 	struct rtable *rt;
+	struct ip_options opt;
 
-	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
+	/* Recompile ip options since IPCB may not be valid anymore.
+	 */
+	memset(&opt, 0, sizeof(opt));
+	opt.optlen = ip_hdr(skb)->ihl*4 - sizeof(struct iphdr);
+	if (__ip_options_compile(dev_net(skb->dev), &opt, skb, NULL))
+		return;
+
+	__icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);
 
 	rt = skb_rtable(skb);
 	if (rt)
-- 
2.20.1