From 54abc686c2d111e98228943a7e1e51cc256e35d9 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Sun, 8 Nov 2015 10:54:07 -0800
Subject: net: add skb_to_full_sk() helper and use it in
 selinux_netlbl_skbuff_setsid()

Generalize selinux_skb_sk() added in commit 212cd0895330
("selinux: fix random read in selinux_ip_postroute_compat()")
so that we can use it other contexts.

Use it right away in selinux_netlbl_skbuff_setsid()

Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index f5bf731..2134e6d 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -210,6 +210,18 @@ struct inet_sock {
 #define IP_CMSG_ORIGDSTADDR	BIT(6)
 #define IP_CMSG_CHECKSUM	BIT(7)
 
+/* SYNACK messages might be attached to request sockets.
+ * Some places want to reach the listener in this case.
+ */
+static inline struct sock *skb_to_full_sk(const struct sk_buff *skb)
+{
+	struct sock *sk = skb->sk;
+
+	if (sk && sk->sk_state == TCP_NEW_SYN_RECV)
+		sk = inet_reqsk(sk)->rsk_listener;
+	return sk;
+}
+
 static inline struct inet_sock *inet_sk(const struct sock *sk)
 {
 	return (struct inet_sock *)sk;
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index c9b2d54..23307da 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4931,23 +4931,11 @@ static unsigned int selinux_ipv4_output(void *priv,
 	return selinux_ip_output(skb, PF_INET);
 }
 
-/* SYNACK messages might be attached to request sockets.
- * To get back to sk_security, we need to look at the listener.
- */
-static struct sock *selinux_skb_sk(const struct sk_buff *skb)
-{
-	struct sock *sk = skb->sk;
-
-	if (sk && sk->sk_state == TCP_NEW_SYN_RECV)
-		sk = inet_reqsk(sk)->rsk_listener;
-	return sk;
-}
-
 static unsigned int selinux_ip_postroute_compat(struct sk_buff *skb,
 						int ifindex,
 						u16 family)
 {
-	struct sock *sk = selinux_skb_sk(skb);
+	struct sock *sk = skb_to_full_sk(skb);
 	struct sk_security_struct *sksec;
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
@@ -5002,7 +4990,7 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb,
 	if (!secmark_active && !peerlbl_active)
 		return NF_ACCEPT;
 
-	sk = selinux_skb_sk(skb);
+	sk = skb_to_full_sk(skb);
 
 #ifdef CONFIG_XFRM
 	/* If skb->dst->xfrm is non-NULL then the packet is undergoing an IPsec
diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
index 0364120..1f989a5 100644
--- a/security/selinux/netlabel.c
+++ b/security/selinux/netlabel.c
@@ -245,7 +245,7 @@ int selinux_netlbl_skbuff_setsid(struct sk_buff *skb,
 
 	/* if this is a locally generated packet check to see if it is already
 	 * being labeled by it's parent socket, if it is just exit */
-	sk = skb->sk;
+	sk = skb_to_full_sk(skb);
 	if (sk != NULL) {
 		struct sk_security_struct *sksec = sk->sk_security;
 		if (sksec->nlbl_state != NLBL_REQSKB)
-- 
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