Messages in this thread Patch in this message | | | From | Dmitry Safonov <> | Subject | [PATCH v9 net-next 11/23] net/tcp: Sign SYN-ACK segments with TCP-AO | Date | Wed, 2 Aug 2023 18:26:38 +0100 |
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Similarly to RST segments, wire SYN-ACKs to TCP-AO. tcp_rsk_used_ao() is handy here to check if the request socket used AO and needs a signature on the outgoing segments.
Co-developed-by: Francesco Ruggeri <fruggeri@arista.com> Signed-off-by: Francesco Ruggeri <fruggeri@arista.com> Co-developed-by: Salam Noureddine <noureddine@arista.com> Signed-off-by: Salam Noureddine <noureddine@arista.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Acked-by: David Ahern <dsahern@kernel.org> --- include/net/tcp.h | 3 +++ include/net/tcp_ao.h | 6 +++++ net/ipv4/tcp_ao.c | 22 +++++++++++++++++ net/ipv4/tcp_ipv4.c | 1 + net/ipv4/tcp_output.c | 57 ++++++++++++++++++++++++++++++++++++++----- net/ipv6/tcp_ao.c | 22 +++++++++++++++++ net/ipv6/tcp_ipv6.c | 1 + 7 files changed, 106 insertions(+), 6 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h index 710d75b23b77..97fbe14a1275 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2180,6 +2180,9 @@ struct tcp_request_sock_ops { struct request_sock *req, int sndid, int rcvid); int (*ao_calc_key)(struct tcp_ao_key *mkt, u8 *key, struct request_sock *sk); + int (*ao_synack_hash)(char *ao_hash, struct tcp_ao_key *mkt, + struct request_sock *req, const struct sk_buff *skb, + int hash_offset, u32 sne); #endif #ifdef CONFIG_SYN_COOKIES __u32 (*cookie_init_seq)(const struct sk_buff *skb, diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h index 409646be90c3..ead52113591e 100644 --- a/include/net/tcp_ao.h +++ b/include/net/tcp_ao.h @@ -144,6 +144,9 @@ int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb, int tcp_v4_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen); struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk, int sndid, int rcvid); +int tcp_v4_ao_synack_hash(char *ao_hash, struct tcp_ao_key *mkt, + struct request_sock *req, const struct sk_buff *skb, + int hash_offset, u32 sne); int tcp_v4_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key, const struct sock *sk, __be32 sisn, __be32 disn, bool send); @@ -178,6 +181,9 @@ int tcp_v6_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key, const struct sock *sk, const struct sk_buff *skb, const u8 *tkey, int hash_offset, u32 sne); int tcp_v6_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen); +int tcp_v6_ao_synack_hash(char *ao_hash, struct tcp_ao_key *ao_key, + struct request_sock *req, const struct sk_buff *skb, + int hash_offset, u32 sne); void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb); void tcp_ao_connect_init(struct sock *sk); void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb, diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index 94ca87240c17..a3f26a2ab690 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -568,6 +568,28 @@ int tcp_v4_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key, tkey, hash_offset, sne); } +int tcp_v4_ao_synack_hash(char *ao_hash, struct tcp_ao_key *ao_key, + struct request_sock *req, const struct sk_buff *skb, + int hash_offset, u32 sne) +{ + void *hash_buf = NULL; + int err; + + hash_buf = kmalloc(tcp_ao_digest_size(ao_key), GFP_ATOMIC); + if (!hash_buf) + return -ENOMEM; + + err = tcp_v4_ao_calc_key_rsk(ao_key, hash_buf, req); + if (err) + goto out; + + err = tcp_ao_hash_skb(AF_INET, ao_hash, ao_key, req_to_sk(req), skb, + hash_buf, hash_offset, sne); +out: + kfree(hash_buf); + return err; +} + struct tcp_ao_key *tcp_v4_ao_lookup_rsk(const struct sock *sk, struct request_sock *req, int sndid, int rcvid) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index e25da6641e44..b797ea705818 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1676,6 +1676,7 @@ const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = { #ifdef CONFIG_TCP_AO .ao_lookup = tcp_v4_ao_lookup_rsk, .ao_calc_key = tcp_v4_ao_calc_key_rsk, + .ao_synack_hash = tcp_v4_ao_synack_hash, #endif #ifdef CONFIG_SYN_COOKIES .cookie_init_seq = cookie_v4_init_sequence, diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 61bb2c5b130b..e455084c4a7b 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -892,6 +892,7 @@ static unsigned int tcp_synack_options(const struct sock *sk, unsigned int mss, struct sk_buff *skb, struct tcp_out_options *opts, const struct tcp_md5sig_key *md5, + const struct tcp_ao_key *ao, struct tcp_fastopen_cookie *foc, enum tcp_synack_type synack_type, struct sk_buff *syn_skb) @@ -913,6 +914,14 @@ static unsigned int tcp_synack_options(const struct sock *sk, ireq->tstamp_ok &= !ireq->sack_ok; } #endif +#ifdef CONFIG_TCP_AO + if (ao) { + opts->options |= OPTION_AO; + remaining -= tcp_ao_len(ao); + ireq->tstamp_ok &= !ireq->sack_ok; + } +#endif + WARN_ON_ONCE(md5 && ao); /* We always send an MSS option. */ opts->mss = mss; @@ -3712,6 +3721,7 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, struct inet_request_sock *ireq = inet_rsk(req); const struct tcp_sock *tp = tcp_sk(sk); struct tcp_md5sig_key *md5 = NULL; + struct tcp_ao_key *ao_key = NULL; struct tcp_out_options opts; struct sk_buff *skb; int tcp_header_size; @@ -3762,16 +3772,43 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, tcp_rsk(req)->snt_synack = tcp_skb_timestamp_us(skb); } -#ifdef CONFIG_TCP_MD5SIG +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) rcu_read_lock(); - md5 = tcp_rsk(req)->af_specific->req_md5_lookup(sk, req_to_sk(req)); #endif + if (tcp_rsk_used_ao(req)) { +#ifdef CONFIG_TCP_AO + u8 maclen = tcp_rsk(req)->maclen; + u8 keyid = tcp_rsk(req)->ao_keyid; + + ao_key = tcp_sk(sk)->af_specific->ao_lookup(sk, req_to_sk(req), + keyid, -1); + /* If there is no matching key - avoid sending anything, + * especially usigned segments. It could try harder and lookup + * for another peer-matching key, but the peer has requested + * ao_keyid (RFC5925 RNextKeyID), so let's keep it simple here. + */ + if (unlikely(!ao_key || tcp_ao_maclen(ao_key) != maclen)) { + rcu_read_unlock(); + skb_dst_drop(skb); + kfree_skb(skb); + net_warn_ratelimited("TCP-AO: the keyid %u with maclen %u|%u from SYN packet is not present - not sending SYNACK\n", + keyid, maclen, + ao_key ? tcp_ao_maclen(ao_key) : 0); + return NULL; + } +#endif + } else { +#ifdef CONFIG_TCP_MD5SIG + md5 = tcp_rsk(req)->af_specific->req_md5_lookup(sk, + req_to_sk(req)); +#endif + } skb_set_hash(skb, READ_ONCE(tcp_rsk(req)->txhash), PKT_HASH_TYPE_L4); /* bpf program will be interested in the tcp_flags */ TCP_SKB_CB(skb)->tcp_flags = TCPHDR_SYN | TCPHDR_ACK; tcp_header_size = tcp_synack_options(sk, req, mss, skb, &opts, md5, - foc, synack_type, - syn_skb) + sizeof(*th); + ao_key, foc, synack_type, syn_skb) + + sizeof(*th); skb_push(skb, tcp_header_size); skb_reset_transport_header(skb); @@ -3791,7 +3828,7 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, /* RFC1323: The window in SYN & SYN/ACK segments is never scaled. */ th->window = htons(min(req->rsk_rcv_wnd, 65535U)); - tcp_options_write(th, NULL, NULL, &opts, NULL); + tcp_options_write(th, NULL, tcp_rsk(req), &opts, ao_key); th->doff = (tcp_header_size >> 2); TCP_INC_STATS(sock_net(sk), TCP_MIB_OUTSEGS); @@ -3799,7 +3836,15 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, /* Okay, we have all we need - do the md5 hash if needed */ if (md5) tcp_rsk(req)->af_specific->calc_md5_hash(opts.hash_location, - md5, req_to_sk(req), skb); + md5, req_to_sk(req), skb); +#endif +#ifdef CONFIG_TCP_AO + if (ao_key) + tcp_rsk(req)->af_specific->ao_synack_hash(opts.hash_location, + ao_key, req, skb, + opts.hash_location - (u8 *)th, 0); +#endif +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) rcu_read_unlock(); #endif diff --git a/net/ipv6/tcp_ao.c b/net/ipv6/tcp_ao.c index c9a6fa84f6ce..99753e12c08c 100644 --- a/net/ipv6/tcp_ao.c +++ b/net/ipv6/tcp_ao.c @@ -144,3 +144,25 @@ int tcp_v6_parse_ao(struct sock *sk, int cmd, { return tcp_parse_ao(sk, cmd, AF_INET6, optval, optlen); } + +int tcp_v6_ao_synack_hash(char *ao_hash, struct tcp_ao_key *ao_key, + struct request_sock *req, const struct sk_buff *skb, + int hash_offset, u32 sne) +{ + void *hash_buf = NULL; + int err; + + hash_buf = kmalloc(tcp_ao_digest_size(ao_key), GFP_ATOMIC); + if (!hash_buf) + return -ENOMEM; + + err = tcp_v6_ao_calc_key_rsk(ao_key, hash_buf, req); + if (err) + goto out; + + err = tcp_ao_hash_skb(AF_INET6, ao_hash, ao_key, req_to_sk(req), skb, + hash_buf, hash_offset, sne); +out: + kfree(hash_buf); + return err; +} diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 7fd9f40f85aa..eeb2d2b96974 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -845,6 +845,7 @@ const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = { #ifdef CONFIG_TCP_AO .ao_lookup = tcp_v6_ao_lookup_rsk, .ao_calc_key = tcp_v6_ao_calc_key_rsk, + .ao_synack_hash = tcp_v6_ao_synack_hash, #endif #ifdef CONFIG_SYN_COOKIES .cookie_init_seq = cookie_v6_init_sequence, -- 2.41.0
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