From da7dfaa6d6f731c30eca6ffa808b83634d43e26f Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Mon, 4 Dec 2023 19:00:41 +0000 Subject: net/tcp: Consistently align TCP-AO option in the header Currently functions that pre-calculate TCP header options length use unaligned TCP-AO header + MAC-length for skb reservation. And the functions that actually write TCP-AO options into skb do align the header. Nothing good can come out of this for ((maclen % 4) != 0). Provide tcp_ao_len_aligned() helper and use it everywhere for TCP header options space calculations. Fixes: 1e03d32bea8e ("net/tcp: Add TCP-AO sign to outgoing packets") Signed-off-by: Dmitry Safonov Reviewed-by: Eric Dumazet Signed-off-by: Paolo Abeni --- net/ipv4/tcp_ao.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/ipv4/tcp_ao.c') diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index 7696417d0640..c8be1d526eac 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -1100,7 +1100,7 @@ void tcp_ao_connect_init(struct sock *sk) ao_info->current_key = key; if (!ao_info->rnext_key) ao_info->rnext_key = key; - tp->tcp_header_len += tcp_ao_len(key); + tp->tcp_header_len += tcp_ao_len_aligned(key); ao_info->lisn = htonl(tp->write_seq); ao_info->snd_sne = 0; @@ -1346,7 +1346,7 @@ static int tcp_ao_parse_crypto(struct tcp_ao_add *cmd, struct tcp_ao_key *key) syn_tcp_option_space -= TCPOLEN_MSS_ALIGNED; syn_tcp_option_space -= TCPOLEN_TSTAMP_ALIGNED; syn_tcp_option_space -= TCPOLEN_WSCALE_ALIGNED; - if (tcp_ao_len(key) > syn_tcp_option_space) { + if (tcp_ao_len_aligned(key) > syn_tcp_option_space) { err = -EMSGSIZE; goto err_kfree; } -- cgit v1.2.3 From 12083d728213285c2d4347fa0ed3b556449703ce Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Mon, 4 Dec 2023 19:00:43 +0000 Subject: net/tcp: Don't add key with non-matching VRF on connected sockets 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 Reviewed-by: Eric Dumazet Signed-off-by: Paolo Abeni --- net/ipv4/tcp_ao.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'net/ipv4/tcp_ao.c') diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index c8be1d526eac..18dacfef7a07 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -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 -- cgit v1.2.3 From 9396c4ee93f9ac03cd0cea0bb345fbc657772943 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Mon, 4 Dec 2023 19:00:44 +0000 Subject: net/tcp: Don't store TCP-AO maclen on reqsk This extra check doesn't work for a handshake when SYN segment has (current_key.maclen != rnext_key.maclen). It could be amended to preserve rnext_key.maclen instead of current_key.maclen, but that requires a lookup on listen socket. Originally, this extra maclen check was introduced just because it was cheap. Drop it and convert tcp_request_sock::maclen into boolean tcp_request_sock::used_tcp_ao. Fixes: 06b22ef29591 ("net/tcp: Wire TCP-AO to request sockets") Signed-off-by: Dmitry Safonov Reviewed-by: Eric Dumazet Signed-off-by: Paolo Abeni --- net/ipv4/tcp_ao.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/ipv4/tcp_ao.c') diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index 18dacfef7a07..f8308d3f565e 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -851,7 +851,7 @@ void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb, const struct tcp_ao_hdr *aoh; struct tcp_ao_key *key; - treq->maclen = 0; + treq->used_tcp_ao = false; if (tcp_parse_auth_options(th, NULL, &aoh) || !aoh) return; @@ -863,7 +863,7 @@ void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb, treq->ao_rcv_next = aoh->keyid; treq->ao_keyid = aoh->rnext_keyid; - treq->maclen = tcp_ao_maclen(key); + treq->used_tcp_ao = true; } static enum skb_drop_reason -- cgit v1.2.3