netlabel: If PF_INET6, check sk_buff ip header version

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@btinternet.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 22dc1b9d6362..c070dfc0190a 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -1472,6 +1472,16 @@ int netlbl_unlabel_getattr(const struct sk_buff *skb,
                 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;