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/ipv4/tcp_ipv4.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'net/ipv4/tcp_ipv4.c') diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 18c5595e3814..5f693bbd578d 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1087,6 +1087,7 @@ static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, tcp_rsk_used_ao(req)) { const union tcp_md5_addr *addr; const struct tcp_ao_hdr *aoh; + int l3index; /* Invalid TCP option size or twice included auth */ if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) @@ -1095,11 +1096,12 @@ static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, return; addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; - key.ao_key = tcp_ao_do_lookup(sk, addr, AF_INET, + l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0; + key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, aoh->rnext_keyid, -1); if (unlikely(!key.ao_key)) { /* Send ACK with any matching MKT for the peer */ - key.ao_key = tcp_ao_do_lookup(sk, addr, AF_INET, -1, -1); + key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, -1, -1); /* Matching key disappeared (user removed the key?) * let the handshake timeout. */ @@ -1493,6 +1495,7 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, int optname, const union tcp_md5_addr *addr; u8 prefixlen = 32; int l3index = 0; + bool l3flag; u8 flags; if (optlen < sizeof(cmd)) @@ -1505,6 +1508,7 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, int optname, return -EINVAL; flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX; + l3flag = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX; if (optname == TCP_MD5SIG_EXT && cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) { @@ -1542,7 +1546,7 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, int optname, /* Don't allow keys for peers that have a matching TCP-AO key. * See the comment in tcp_ao_add_cmd() */ - if (tcp_ao_required(sk, addr, AF_INET, false)) + if (tcp_ao_required(sk, addr, AF_INET, l3flag ? l3index : -1, false)) return -EKEYREJECTED; return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags, -- cgit v1.2.3