[PATCH v6 23/26] tcp: authopt: tcp_authopt_lookup_send: Add anykey output param

[Leonard Crestez <cdleonard@xxxxxxxxx>]

The anykey param can be used to distinguish between "no keys configured"
and "no keys valid". The former case should result in unsigned traffic
while the latter should result in an error.

Signed-off-by: Leonard Crestez <cdleonard@xxxxxxxxx>
---
 net/ipv4/tcp_authopt.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c
index 3596fc1fb770..1fd665c43b5d 100644
--- a/net/ipv4/tcp_authopt.c
+++ b/net/ipv4/tcp_authopt.c
@@ -378,38 +378,42 @@ static bool better_key_match(struct tcp_authopt_key_info *old, struct tcp_authop
  * tcp_authopt_lookup_send - lookup key for sending
  *
  * @net: Per-namespace information containing keys
  * @addr_sk: Socket used for destination address lookup
  * @send_id: Optional send_id. If >= 0 then only return keys that match
+ * @anykey: Set to true if any keys are present for the peer
  *
  * If anykey is false then authentication is not required for peer.
  *
  * If anykey is true but no key was found then all our keys must be expired and sending should fail.
  */
 static struct tcp_authopt_key_info *tcp_authopt_lookup_send(struct netns_tcp_authopt *net,
 							    const struct sock *addr_sk,
-							    int send_id)
+							    int send_id,
+							    bool *anykey)
 {
 	struct tcp_authopt_key_info *result = NULL;
 	struct tcp_authopt_key_info *key;
 	int l3index = -1;
 
 	hlist_for_each_entry_rcu(key, &net->head, node, 0) {
-		if (send_id >= 0 && key->send_id != send_id)
-			continue;
-		if (key->flags & TCP_AUTHOPT_KEY_NOSEND)
-			continue;
 		if (key->flags & TCP_AUTHOPT_KEY_ADDR_BIND)
 			if (!tcp_authopt_key_match_sk_addr(key, addr_sk))
 				continue;
 		if (key->flags & TCP_AUTHOPT_KEY_IFINDEX) {
 			if (l3index < 0)
 				l3index = l3mdev_master_ifindex_by_index(sock_net(addr_sk),
 									 addr_sk->sk_bound_dev_if);
 			if (l3index != key->l3index)
 				continue;
 		}
+		if (anykey)
+			*anykey = true;
+		if (key->flags & TCP_AUTHOPT_KEY_NOSEND)
+			continue;
+		if (send_id >= 0 && key->send_id != send_id)
+			continue;
 		if (better_key_match(result, key))
 			result = key;
 		else if (result)
 			net_warn_ratelimited("ambiguous tcp authentication keys configured for send\n");
 	}
@@ -454,14 +458,14 @@ struct tcp_authopt_key_info *__tcp_authopt_select_key(const struct sock *sk,
 		 */
 		if (info->flags & TCP_AUTHOPT_FLAG_LOCK_KEYID)
 			send_id = info->send_keyid;
 		else
 			send_id = rsk->recv_rnextkeyid;
-		key = tcp_authopt_lookup_send(net, addr_sk, send_id);
+		key = tcp_authopt_lookup_send(net, addr_sk, send_id, NULL);
 		/* If no key found with specific send_id try anything else. */
 		if (!key)
-			key = tcp_authopt_lookup_send(net, addr_sk, -1);
+			key = tcp_authopt_lookup_send(net, addr_sk, -1, NULL);
 		if (key)
 			*rnextkeyid = key->recv_id;
 		return key;
 	}
 
@@ -482,18 +486,22 @@ struct tcp_authopt_key_info *__tcp_authopt_select_key(const struct sock *sk,
 	 */
 	if (info->flags & TCP_AUTHOPT_FLAG_LOCK_KEYID) {
 		int send_keyid = info->send_keyid;
 
 		if (!key || key->send_id != send_keyid)
-			new_key = tcp_authopt_lookup_send(net, addr_sk, send_keyid);
+			new_key = tcp_authopt_lookup_send(net, addr_sk,
+							  send_keyid,
+							  NULL);
 	} else {
 		if (!key || key->send_id != info->recv_rnextkeyid)
-			new_key = tcp_authopt_lookup_send(net, addr_sk, info->recv_rnextkeyid);
+			new_key = tcp_authopt_lookup_send(net, addr_sk,
+							  info->recv_rnextkeyid,
+							  NULL);
 	}
 	/* If no key found with specific send_id try anything else. */
 	if (!key && !new_key)
-		new_key = tcp_authopt_lookup_send(net, addr_sk, -1);
+		new_key = tcp_authopt_lookup_send(net, addr_sk, -1, NULL);
 
 	/* Update current key only if we hold the socket lock. */
 	if (new_key && key != new_key) {
 		if (locked) {
 			if (kref_get_unless_zero(&new_key->ref)) {
-- 
2.25.1