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Message-ID: <20230918190027.613430-12-dima@arista.com>
Date: Mon, 18 Sep 2023 20:00:09 +0100
From: Dmitry Safonov <dima@...sta.com>
To: David Ahern <dsahern@...nel.org>,
Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>,
Jakub Kicinski <kuba@...nel.org>,
"David S. Miller" <davem@...emloft.net>
Cc: linux-kernel@...r.kernel.org, Dmitry Safonov <dima@...sta.com>,
Andy Lutomirski <luto@...capital.net>,
Ard Biesheuvel <ardb@...nel.org>,
Bob Gilligan <gilligan@...sta.com>,
Dan Carpenter <error27@...il.com>,
David Laight <David.Laight@...lab.com>,
Dmitry Safonov <0x7f454c46@...il.com>,
Donald Cassidy <dcassidy@...hat.com>,
Eric Biggers <ebiggers@...nel.org>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Francesco Ruggeri <fruggeri05@...il.com>,
"Gaillardetz, Dominik" <dgaillar@...na.com>,
Herbert Xu <herbert@...dor.apana.org.au>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
Ivan Delalande <colona@...sta.com>,
Leonard Crestez <cdleonard@...il.com>,
"Nassiri, Mohammad" <mnassiri@...na.com>,
Salam Noureddine <noureddine@...sta.com>,
Simon Horman <simon.horman@...igine.com>,
"Tetreault, Francois" <ftetreau@...na.com>, netdev@...r.kernel.org
Subject: [PATCH v12 net-next 11/23] net/tcp: Sign SYN-ACK segments with TCP-AO
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@...sta.com>
Signed-off-by: Francesco Ruggeri <fruggeri@...sta.com>
Co-developed-by: Salam Noureddine <noureddine@...sta.com>
Signed-off-by: Salam Noureddine <noureddine@...sta.com>
Signed-off-by: Dmitry Safonov <dima@...sta.com>
Acked-by: David Ahern <dsahern@...nel.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 | 72 +++++++++++++++++++++++++++++++++----------
net/ipv6/tcp_ao.c | 22 +++++++++++++
net/ipv6/tcp_ipv6.c | 1 +
7 files changed, 111 insertions(+), 16 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 29734c882178..fae59dfa5ab4 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2179,6 +2179,9 @@ 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 d26d98f1b048..c922d2e31d08 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 b114f3d901a0..0d8ea381300b 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 26392304a99e..b0cf5dd17222 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1679,6 +1679,7 @@ 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 4dc9875975aa..42bdc1b0c68b 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -887,7 +887,7 @@ static unsigned int tcp_synack_options(const struct sock *sk,
struct request_sock *req,
unsigned int mss, struct sk_buff *skb,
struct tcp_out_options *opts,
- const struct tcp_md5sig_key *md5,
+ const struct tcp_key *key,
struct tcp_fastopen_cookie *foc,
enum tcp_synack_type synack_type,
struct sk_buff *syn_skb)
@@ -895,8 +895,7 @@ static unsigned int tcp_synack_options(const struct sock *sk,
struct inet_request_sock *ireq = inet_rsk(req);
unsigned int remaining = MAX_TCP_OPTION_SPACE;
-#ifdef CONFIG_TCP_MD5SIG
- if (md5) {
+ if (tcp_key_is_md5(key)) {
opts->options |= OPTION_MD5;
remaining -= TCPOLEN_MD5SIG_ALIGNED;
@@ -907,8 +906,11 @@ static unsigned int tcp_synack_options(const struct sock *sk,
*/
if (synack_type != TCP_SYNACK_COOKIE)
ireq->tstamp_ok &= !ireq->sack_ok;
+ } else if (tcp_key_is_ao(key)) {
+ opts->options |= OPTION_AO;
+ remaining -= tcp_ao_len(key->ao_key);
+ ireq->tstamp_ok &= !ireq->sack_ok;
}
-#endif
/* We always send an MSS option. */
opts->mss = mss;
@@ -3678,7 +3680,6 @@ 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_out_options opts;
struct tcp_key key = {};
struct sk_buff *skb;
@@ -3730,18 +3731,48 @@ 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));
- if (md5)
- key.type = TCP_KEY_MD5;
#endif
+ if (tcp_rsk_used_ao(req)) {
+#ifdef CONFIG_TCP_AO
+ struct tcp_ao_key *ao_key = NULL;
+ 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)) {
+ u8 key_maclen = ao_key ? tcp_ao_maclen(ao_key) : 0;
+
+ rcu_read_unlock();
+ 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, key_maclen);
+ return NULL;
+ }
+ key.ao_key = ao_key;
+ key.type = TCP_KEY_AO;
+#endif
+ } else {
+#ifdef CONFIG_TCP_MD5SIG
+ key.md5_key = tcp_rsk(req)->af_specific->req_md5_lookup(sk,
+ req_to_sk(req));
+ if (key.md5_key)
+ key.type = TCP_KEY_MD5;
+#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);
+ tcp_header_size = tcp_synack_options(sk, req, mss, skb, &opts,
+ &key, foc, synack_type, syn_skb)
+ + sizeof(*th);
skb_push(skb, tcp_header_size);
skb_reset_transport_header(skb);
@@ -3761,15 +3792,24 @@ 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, &key);
+ tcp_options_write(th, NULL, tcp_rsk(req), &opts, &key);
th->doff = (tcp_header_size >> 2);
TCP_INC_STATS(sock_net(sk), TCP_MIB_OUTSEGS);
-#ifdef CONFIG_TCP_MD5SIG
/* Okay, we have all we need - do the md5 hash if needed */
- if (md5)
+ if (tcp_key_is_md5(&key)) {
+#ifdef CONFIG_TCP_MD5SIG
tcp_rsk(req)->af_specific->calc_md5_hash(opts.hash_location,
- md5, req_to_sk(req), skb);
+ key.md5_key, req_to_sk(req), skb);
+#endif
+ } else if (tcp_key_is_ao(&key)) {
+#ifdef CONFIG_TCP_AO
+ tcp_rsk(req)->af_specific->ao_synack_hash(opts.hash_location,
+ key.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 f1bb92a9ee8f..2f7e68d24559 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -838,6 +838,7 @@ 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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