@@ -1608,6 +1608,15 @@ static int tcp_ao_add_cmd(struct sock *sk, unsigned short int family,
if (!dev || !l3index)
return -EINVAL;
+ if (!bound_dev_if || bound_dev_if != cmd.ifindex) {
+ /* tcp_ao_established_key() doesn't expect having
+ * non peer-matching key on an established TCP-AO
+ * connection.
+ */
+ if (!((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)))
+ return -EINVAL;
+ }
+
/* It's still possible to bind after adding keys or even
* re-bind to a different dev (with CAP_NET_RAW).
* So, no reason to return error here, rather try to be
If the connection was established, don't allow adding TCP-AO keys that don't match the peer. Currently, there are checks for ip-address matching, but L3 index check is missing. Add it to restrict userspace shooting itself somewhere. Yet, nothing restricts the CAP_NET_RAW user from trying to shoot themselves by performing setsockopt(SO_BINDTODEVICE) or setsockopt(SO_BINDTOIFINDEX) over an established TCP-AO connection. So, this is just "minimum effort" to potentially save someone's debugging time, rather than a full restriction on doing weird things. Fixes: 248411b8cb89 ("net/tcp: Wire up l3index to TCP-AO") Signed-off-by: Dmitry Safonov <dima@arista.com> Reviewed-by: Eric Dumazet <edumazet@google.com> --- net/ipv4/tcp_ao.c | 9 +++++++++ 1 file changed, 9 insertions(+)