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Miller" Cc: linux-kernel@vger.kernel.org, Dmitry Safonov , Andy Lutomirski , Ard Biesheuvel , Bob Gilligan , Dan Carpenter , David Laight , Dmitry Safonov <0x7f454c46@gmail.com>, Donald Cassidy , Eric Biggers , "Eric W. Biederman" , Francesco Ruggeri , "Gaillardetz, Dominik" , Herbert Xu , Hideaki YOSHIFUJI , Ivan Delalande , Leonard Crestez , Salam Noureddine , "Tetreault, Francois" , netdev@vger.kernel.org Subject: [PATCH v8.1 net-next 11/23] net/tcp: Sign SYN-ACK segments with TCP-AO Date: Fri, 21 Jul 2023 17:19:02 +0100 Message-ID: <20230721161916.542667-12-dima@arista.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230721161916.542667-1-dima@arista.com> References: <20230721161916.542667-1-dima@arista.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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 Signed-off-by: Francesco Ruggeri Co-developed-by: Salam Noureddine Signed-off-by: Salam Noureddine Signed-off-by: Dmitry Safonov --- include/net/tcp.h | 4 ++++ include/net/tcp_ao.h | 6 ++++++ net/ipv4/tcp_ao.c | 22 ++++++++++++++++++++ net/ipv4/tcp_ipv4.c | 1 + net/ipv4/tcp_output.c | 48 +++++++++++++++++++++++++++++++++++++------ net/ipv6/tcp_ao.c | 22 ++++++++++++++++++++ net/ipv6/tcp_ipv6.c | 1 + 7 files changed, 98 insertions(+), 6 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index b8be3aefb9c4..ad300e5b6eb8 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2177,6 +2177,10 @@ struct tcp_request_sock_ops { 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 b63c4f2c36ea..4979c993973f 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 optname, sockptr_t optval, int op= tlen); struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *ad= dr_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 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 be9349239139..0233cf363de9 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -546,6 +546,28 @@ int tcp_v4_ao_hash_skb(char *ao_hash, struct tcp_ao_ke= y *key, tkey, hash_offset, sne); } =20 +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 =3D NULL; + int err; + + hash_buf =3D kmalloc(tcp_ao_digest_size(ao_key), GFP_ATOMIC); + if (!hash_buf) + return -ENOMEM; + + err =3D tcp_v4_ao_calc_key_rsk(ao_key, hash_buf, req); + if (err) + goto out; + + err =3D 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 12b952d0dcf4..884d9f854276 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1678,6 +1678,7 @@ const struct tcp_request_sock_ops tcp_request_sock_ip= v4_ops =3D { #ifdef CONFIG_TCP_AO .ao_lookup =3D tcp_v4_ao_lookup_rsk, .ao_calc_key =3D tcp_v4_ao_calc_key_rsk, + .ao_synack_hash =3D tcp_v4_ao_synack_hash, #endif #ifdef CONFIG_SYN_COOKIES .cookie_init_seq =3D cookie_v4_init_sequence, diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 27f7aaad5490..ed1164f287b7 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3722,6 +3722,7 @@ struct sk_buff *tcp_make_synack(const struct sock *sk= , struct dst_entry *dst, struct inet_request_sock *ireq =3D inet_rsk(req); const struct tcp_sock *tp =3D tcp_sk(sk); struct tcp_md5sig_key *md5 =3D NULL; + struct tcp_ao_key *ao_key =3D NULL; struct tcp_out_options opts; struct sk_buff *skb; int tcp_header_size; @@ -3772,16 +3773,43 @@ struct sk_buff *tcp_make_synack(const struct sock *= sk, struct dst_entry *dst, tcp_rsk(req)->snt_synack =3D tcp_skb_timestamp_us(skb); } =20 -#ifdef CONFIG_TCP_MD5SIG +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) rcu_read_lock(); - md5 =3D 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 =3D tcp_rsk(req)->maclen; + u8 keyid =3D tcp_rsk(req)->ao_keyid; + + ao_key =3D 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) !=3D 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 p= acket 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 =3D 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 =3D TCPHDR_SYN | TCPHDR_ACK; tcp_header_size =3D tcp_synack_options(sk, req, mss, skb, &opts, md5, - NULL, foc, synack_type, - syn_skb) + sizeof(*th); + ao_key, foc, synack_type, syn_skb) + + sizeof(*th); =20 skb_push(skb, tcp_header_size); skb_reset_transport_header(skb); @@ -3801,7 +3829,7 @@ struct sk_buff *tcp_make_synack(const struct sock *sk= , struct dst_entry *dst, =20 /* RFC1323: The window in SYN & SYN/ACK segments is never scaled. */ th->window =3D 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 =3D (tcp_header_size >> 2); TCP_INC_STATS(sock_net(sk), TCP_MIB_OUTSEGS); =20 @@ -3809,7 +3837,15 @@ struct sk_buff *tcp_make_synack(const struct sock *s= k, 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 =20 diff --git a/net/ipv6/tcp_ao.c b/net/ipv6/tcp_ao.c index 65fa52f8c2e3..ec320781bc5c 100644 --- a/net/ipv6/tcp_ao.c +++ b/net/ipv6/tcp_ao.c @@ -133,3 +133,25 @@ 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 =3D NULL; + int err; + + hash_buf =3D kmalloc(tcp_ao_digest_size(ao_key), GFP_ATOMIC); + if (!hash_buf) + return -ENOMEM; + + err =3D tcp_v6_ao_calc_key_rsk(ao_key, hash_buf, req); + if (err) + goto out; + + err =3D 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 6905484077db..000e4e5309d3 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 =3D { #ifdef CONFIG_TCP_AO .ao_lookup =3D tcp_v6_ao_lookup_rsk, .ao_calc_key =3D tcp_v6_ao_calc_key_rsk, + .ao_synack_hash =3D tcp_v6_ao_synack_hash, #endif #ifdef CONFIG_SYN_COOKIES .cookie_init_seq =3D cookie_v6_init_sequence, --=20 2.41.0