net/tls: prevent bad memory access in tls_is_sk_tx_device_offloaded()

Unlike '&&' operator, the '&' does not have short-circuit
evaluation semantics.  IOW both sides of the operator always
get evaluated.  Fix the wrong operator in
tls_is_sk_tx_device_offloaded(), which would lead to
out-of-bounds access for for non-full sockets.

Fixes: 4799ac81e5 ("tls: Add rx inline crypto offload")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tls.h

@@ -381,7 +381,7 @@ tls_validate_xmit_skb(struct sock *sk, struct net_device *dev,
 static inline bool tls_is_sk_tx_device_offloaded(struct sock *sk)
 {
 #ifdef CONFIG_SOCK_VALIDATE_XMIT
-	return sk_fullsock(sk) &
+	return sk_fullsock(sk) &&
 	       (smp_load_acquire(&sk->sk_validate_xmit_skb) ==
 	       &tls_validate_xmit_skb);
 #else