[PATCH 4.16 257/272] netlabel: If PF_INET6, check sk_buff ip header version

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Richard Haines <richard_c_haines@xxxxxxxxxxxxxx>

[ Upstream commit 213d7f94775322ba44e0bbb55ec6946e9de88cea ]

When resolving a fallback label, check the sk_buff version as it
is possible (e.g. SCTP) to have family = PF_INET6 while
receiving ip_hdr(skb)->version = 4.

Signed-off-by: Richard Haines <richard_c_haines@xxxxxxxxxxxxxx>
Acked-by: Paul Moore <paul@xxxxxxxxxxxxxx>
Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/netlabel/netlabel_unlabeled.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -1472,6 +1472,16 @@ int netlbl_unlabel_getattr(const struct
 		iface = rcu_dereference(netlbl_unlhsh_def);
 	if (iface == NULL || !iface->valid)
 		goto unlabel_getattr_nolabel;
+
+#if IS_ENABLED(CONFIG_IPV6)
+	/* When resolving a fallback label, check the sk_buff version as
+	 * it is possible (e.g. SCTP) to have family = PF_INET6 while
+	 * receiving ip_hdr(skb)->version = 4.
+	 */
+	if (family == PF_INET6 && ip_hdr(skb)->version == 4)
+		family = PF_INET;
+#endif /* IPv6 */
+
 	switch (family) {
 	case PF_INET: {
 		struct iphdr *hdr4;