From 248411b8cb8974a1e1c8e43123c1e682fbd64969 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Mon, 23 Oct 2023 20:22:13 +0100 Subject: net/tcp: Wire up l3index to TCP-AO Similarly how TCP_MD5SIG_FLAG_IFINDEX works for TCP-MD5, TCP_AO_KEYF_IFINDEX is an AO-key flag that binds that MKT to a specified by L3 ifinndex. Similarly, without this flag the key will work in the default VRF l3index = 0 for connections. To prevent AO-keys from overlapping, it's restricted to add key B for a socket that has key A, which have the same sndid/rcvid and one of the following is true: - !(A.keyflags & TCP_AO_KEYF_IFINDEX) or !(B.keyflags & TCP_AO_KEYF_IFINDEX) so that any key is non-bound to a VRF - A.l3index == B.l3index both want to work for the same VRF Additionally, it's restricted to match TCP-MD5 keys for the same peer the following way: |--------------|--------------------|----------------|---------------| | | MD5 key without | MD5 key | MD5 key | | | l3index | l3index=0 | l3index=N | |--------------|--------------------|----------------|---------------| | TCP-AO key | | | | | without | reject | reject | reject | | l3index | | | | |--------------|--------------------|----------------|---------------| | TCP-AO key | | | | | l3index=0 | reject | reject | allow | |--------------|--------------------|----------------|---------------| | TCP-AO key | | | | | l3index=N | reject | allow | reject | |--------------|--------------------|----------------|---------------| This is done with the help of tcp_md5_do_lookup_any_l3index() to reject adding AO key without TCP_AO_KEYF_IFINDEX if there's TCP-MD5 in any VRF. This is important for case where sysctl_tcp_l3mdev_accept = 1 Similarly, for TCP-AO lookups tcp_ao_do_lookup() may be used with l3index < 0, so that __tcp_ao_key_cmp() will match TCP-AO key in any VRF. Signed-off-by: Dmitry Safonov Acked-by: David Ahern Signed-off-by: David S. Miller --- net/ipv6/syncookies.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'net/ipv6/syncookies.c') diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c index ad7a8caa7b2a..500f6ed3b8cf 100644 --- a/net/ipv6/syncookies.c +++ b/net/ipv6/syncookies.c @@ -140,6 +140,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb) struct dst_entry *dst; __u8 rcv_wscale; u32 tsoff = 0; + int l3index; if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_syncookies) || !th->ack || th->rst) @@ -214,7 +215,9 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb) treq->snt_isn = cookie; treq->ts_off = 0; treq->txhash = net_tx_rndhash(); - tcp_ao_syncookie(sk, skb, treq, AF_INET6); + + l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif); + tcp_ao_syncookie(sk, skb, treq, AF_INET6, l3index); if (IS_ENABLED(CONFIG_SMC)) ireq->smc_ok = 0; -- cgit v1.2.3