tls: clear key material from kernel memory when do_tls_setsockopt_conf fails

Fixes: 3c4d7559 ("tls: kernel TLS support")
Signed-off-by: NSabrina Dubroca <sd@queasysnail.net>
Signed-off-by: NSabrina Dubroca <sd@queasysnail.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/tls/tls_main.c

@@ -509,7 +509,7 @@ static int do_tls_setsockopt_conf(struct sock *sk, char __user *optval,
 	goto out;
 
 err_crypto_info:
-	memset(crypto_info, 0, sizeof(*crypto_info));
+	memzero_explicit(crypto_info, sizeof(union tls_crypto_context));
 out:
 	return rc;
 }