From 3b448977879f7b25f5171de3b58755658f92f1ae Mon Sep 17 00:00:00 2001
From: Nazarov Sergey <s-nazarov@yandex.ru>
Date: Mon, 25 Feb 2019 19:27:15 +0300
Subject: [PATCH] net: avoid use IPCB in cipso_v4_error

[ Upstream commit 3da1ed7ac398f34fff1694017a07054d69c5f5c5 ]

Extract IP options in cipso_v4_error and use __icmp_send.

Signed-off-by: Sergey Nazarov <s-nazarov@yandex.ru>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/net/ip.h      |  2 ++
 net/ipv4/cipso_ipv4.c | 17 +++++++++++++++--
 net/ipv4/ip_options.c | 22 +++++++++++++++++-----
 3 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/include/net/ip.h b/include/net/ip.h
index 8646da034851..f06cd30bb44c 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -570,6 +570,8 @@ static inline int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb)
 }
 
 void ip_options_fragment(struct sk_buff *skb);
+int __ip_options_compile(struct net *net, struct ip_options *opt,
+			 struct sk_buff *skb, __be32 *info);
 int ip_options_compile(struct net *net, struct ip_options *opt,
 		       struct sk_buff *skb);
 int ip_options_get(struct net *net, struct ip_options_rcu **optp,
diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index 9f6102f81761..71bcab94c5c7 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -1736,13 +1736,26 @@ validate_return:
  */
 void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
 {
+	unsigned char optbuf[sizeof(struct ip_options) + 40];
+	struct ip_options *opt = (struct ip_options *)optbuf;
+
 	if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
 		return;
 
+	/*
+	 * We might be called above the IP layer,
+	 * so we can not use icmp_send and IPCB here.
+	 */
+
+	memset(opt, 0, sizeof(struct ip_options));
+	opt->optlen = ip_hdr(skb)->ihl*4 - sizeof(struct iphdr);
+	if (__ip_options_compile(dev_net(skb->dev), opt, skb, NULL))
+		return;
+
 	if (gateway)
-		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0);
+		__icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0, opt);
 	else
-		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0);
+		__icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0, opt);
 }
 
 /**
diff --git a/net/ipv4/ip_options.c b/net/ipv4/ip_options.c
index 4d158ff1def1..4cd3b5ad9cee 100644
--- a/net/ipv4/ip_options.c
+++ b/net/ipv4/ip_options.c
@@ -253,8 +253,9 @@ static void spec_dst_fill(__be32 *spec_dst, struct sk_buff *skb)
  * If opt == NULL, then skb->data should point to IP header.
  */
 
-int ip_options_compile(struct net *net,
-		       struct ip_options *opt, struct sk_buff *skb)
+int __ip_options_compile(struct net *net,
+			 struct ip_options *opt, struct sk_buff *skb,
+			 __be32 *info)
 {
 	__be32 spec_dst = htonl(INADDR_ANY);
 	unsigned char *pp_ptr = NULL;
@@ -470,11 +471,22 @@ eol:
 		return 0;
 
 error:
-	if (skb) {
-		icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
-	}
+	if (info)
+		*info = htonl((pp_ptr-iph)<<24);
 	return -EINVAL;
 }
+
+int ip_options_compile(struct net *net,
+		       struct ip_options *opt, struct sk_buff *skb)
+{
+	int ret;
+	__be32 info;
+
+	ret = __ip_options_compile(net, opt, skb, &info);
+	if (ret != 0 && skb)
+		icmp_send(skb, ICMP_PARAMETERPROB, 0, info);
+	return ret;
+}
 EXPORT_SYMBOL(ip_options_compile);
 
 /*