[PATCH v9 net-next 09/23] net/tcp: Add TCP-AO sign to twsk

From: Dmitry Safonov
Date: Wed Aug 02 2023 - 13:28:39 EST

Next message: Dmitry Safonov: "[PATCH v9 net-next 08/23] net/tcp: Add AO sign to RST packets"
Previous message: Dmitry Safonov: "[PATCH v9 net-next 07/23] net/tcp: Add tcp_parse_auth_options()"
In reply to: Dmitry Safonov: "[PATCH v9 net-next 07/23] net/tcp: Add tcp_parse_auth_options()"
Next in thread: Dmitry Safonov: "[PATCH v9 net-next 08/23] net/tcp: Add AO sign to RST packets"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Add support for sockets in time-wait state.
ao_info as well as all keys are inherited on transition to time-wait
socket. The lifetime of ao_info is now protected by ref counter, so
that tcp_ao_destroy_sock() will destruct it only when the last user is
gone.

Co-developed-by: Francesco Ruggeri <fruggeri@xxxxxxxxxx>
Signed-off-by: Francesco Ruggeri <fruggeri@xxxxxxxxxx>
Co-developed-by: Salam Noureddine <noureddine@xxxxxxxxxx>
Signed-off-by: Salam Noureddine <noureddine@xxxxxxxxxx>
Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
Acked-by: David Ahern <dsahern@xxxxxxxxxx>
---
include/linux/tcp.h | 3 ++
include/net/tcp_ao.h | 13 +++++++--
net/ipv4/tcp_ao.c | 48 +++++++++++++++++++++++++------
net/ipv4/tcp_ipv4.c | 61 ++++++++++++++++++++++++++++++++++++----
net/ipv4/tcp_minisocks.c | 4 ++-
net/ipv4/tcp_output.c | 2 +-
net/ipv6/tcp_ipv6.c | 41 ++++++++++++++++++++++++---
7 files changed, 149 insertions(+), 23 deletions(-)

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 9eb15e798c32..0cfa8dbf9159 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -502,6 +502,9 @@ struct tcp_timewait_sock {
#ifdef CONFIG_TCP_MD5SIG
struct tcp_md5sig_key *tw_md5_key;
#endif
+#ifdef CONFIG_TCP_AO
+ struct tcp_ao_info __rcu *ao_info;
+#endif
};

static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h
index 67f997aabd9c..ab9163bae48d 100644
--- a/include/net/tcp_ao.h
+++ b/include/net/tcp_ao.h
@@ -85,6 +85,7 @@ struct tcp_ao_info {
__unused :31;
__be32 lisn;
__be32 risn;
+ atomic_t refcnt; /* Protects twsk destruction */
struct rcu_head rcu;
};

@@ -121,7 +122,8 @@ struct tcp_ao_key *tcp_ao_established_key(struct tcp_ao_info *ao,
int sndid, int rcvid);
int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx,
unsigned int len, struct tcp_sigpool *hp);
-void tcp_ao_destroy_sock(struct sock *sk);
+void tcp_ao_destroy_sock(struct sock *sk, bool twsk);
+void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp);
struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk,
const union tcp_ao_addr *addr,
int family, int sndid, int rcvid);
@@ -131,7 +133,7 @@ int tcp_ao_hash_hdr(unsigned short family, char *ao_hash,
const union tcp_ao_addr *saddr,
const struct tcphdr *th, u32 sne);
int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb,
- const struct tcp_ao_hdr *aoh, int l3index, u32 seq,
+ const struct tcp_ao_hdr *aoh, int l3index, __be32 seq,
struct tcp_ao_key **key, char **traffic_key,
bool *allocated_traffic_key, u8 *keyid, u32 *sne);

@@ -171,7 +173,7 @@ static inline struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk,
return NULL;
}

-static inline void tcp_ao_destroy_sock(struct sock *sk)
+static inline void tcp_ao_destroy_sock(struct sock *sk, bool twsk)
{
}

@@ -179,6 +181,11 @@ static inline void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb)
{
}

+static inline void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw,
+ struct tcp_sock *tp)
+{
+}
+
static inline void tcp_ao_connect_init(struct sock *sk)
{
}
diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c
index 81ce4fe546f2..93072a5ada5c 100644
--- a/net/ipv4/tcp_ao.c
+++ b/net/ipv4/tcp_ao.c
@@ -159,6 +159,7 @@ static struct tcp_ao_info *tcp_ao_alloc_info(gfp_t flags)
if (!ao)
return NULL;
INIT_HLIST_HEAD(&ao->head);
+ atomic_set(&ao->refcnt, 1);

return ao;
}
@@ -176,27 +177,54 @@ static void tcp_ao_key_free_rcu(struct rcu_head *head)
kfree(key);
}

-void tcp_ao_destroy_sock(struct sock *sk)
+void tcp_ao_destroy_sock(struct sock *sk, bool twsk)
{
struct tcp_ao_info *ao;
struct tcp_ao_key *key;
struct hlist_node *n;

- ao = rcu_dereference_protected(tcp_sk(sk)->ao_info, 1);
- tcp_sk(sk)->ao_info = NULL;
+ if (twsk) {
+ ao = rcu_dereference_protected(tcp_twsk(sk)->ao_info, 1);
+ tcp_twsk(sk)->ao_info = NULL;
+ } else {
+ ao = rcu_dereference_protected(tcp_sk(sk)->ao_info, 1);
+ tcp_sk(sk)->ao_info = NULL;
+ }

- if (!ao)
+ if (!ao || !atomic_dec_and_test(&ao->refcnt))
return;

hlist_for_each_entry_safe(key, n, &ao->head, node) {
hlist_del_rcu(&key->node);
- atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc);
+ if (!twsk)
+ atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc);
call_rcu(&key->rcu, tcp_ao_key_free_rcu);
}

kfree_rcu(ao, rcu);
}

+void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp)
+{
+ struct tcp_ao_info *ao_info = rcu_dereference_protected(tp->ao_info, 1);
+
+ if (ao_info) {
+ struct tcp_ao_key *key;
+ struct hlist_node *n;
+ int omem = 0;
+
+ hlist_for_each_entry_safe(key, n, &ao_info->head, node) {
+ omem += tcp_ao_sizeof_key(key);
+ }
+
+ atomic_inc(&ao_info->refcnt);
+ atomic_sub(omem, &(((struct sock *)tp)->sk_omem_alloc));
+ rcu_assign_pointer(tcptw->ao_info, ao_info);
+ } else {
+ tcptw->ao_info = NULL;
+ }
+}
+
/* 4 tuple and ISNs are expected in NBO */
static int tcp_v4_ao_calc_key(struct tcp_ao_key *mkt, u8 *key,
__be32 saddr, __be32 daddr,
@@ -496,7 +524,7 @@ struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk,
}

int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb,
- const struct tcp_ao_hdr *aoh, int l3index, u32 seq,
+ const struct tcp_ao_hdr *aoh, int l3index, __be32 seq,
struct tcp_ao_key **key, char **traffic_key,
bool *allocated_traffic_key, u8 *keyid, u32 *sne)
{
@@ -519,8 +547,9 @@ int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb,
struct tcp_ao_key *rnext_key;

if (sk->sk_state == TCP_TIME_WAIT)
- return -1;
- ao_info = rcu_dereference(tcp_sk(sk)->ao_info);
+ ao_info = rcu_dereference(tcp_twsk(sk)->ao_info);
+ else
+ ao_info = rcu_dereference(tcp_sk(sk)->ao_info);
if (!ao_info)
return -ENOENT;

@@ -862,6 +891,9 @@ static struct tcp_ao_info *setsockopt_ao_info(struct sock *sk)
if (sk_fullsock(sk)) {
return rcu_dereference_protected(tcp_sk(sk)->ao_info,
lockdep_sock_is_held(sk));
+ } else if (sk->sk_state == TCP_TIME_WAIT) {
+ return rcu_dereference_protected(tcp_twsk(sk)->ao_info,
+ lockdep_sock_is_held(sk));
}
return ERR_PTR(-ESOCKTNOSUPPORT);
}
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 14e1024141a0..a9f69107b9be 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -912,16 +912,16 @@ static void tcp_v4_send_ack(const struct sock *sk,
struct sk_buff *skb, u32 seq, u32 ack,
u32 win, u32 tsval, u32 tsecr, int oif,
struct tcp_md5sig_key *key,
+ struct tcp_ao_key *ao_key,
+ u8 *traffic_key,
+ u8 rcv_next,
+ u32 ao_sne,
int reply_flags, u8 tos, u32 txhash)
{
const struct tcphdr *th = tcp_hdr(skb);
struct {
struct tcphdr th;
- __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
-#ifdef CONFIG_TCP_MD5SIG
- + (TCPOLEN_MD5SIG_ALIGNED >> 2)
-#endif
- ];
+ __be32 opt[(MAX_TCP_OPTION_SPACE >> 2)];
} rep;
struct net *net = sock_net(sk);
struct ip_reply_arg arg;
@@ -966,6 +966,24 @@ static void tcp_v4_send_ack(const struct sock *sk,
key, ip_hdr(skb)->saddr,
ip_hdr(skb)->daddr, &rep.th);
}
+#endif
+#ifdef CONFIG_TCP_AO
+ if (ao_key) {
+ int offset = (tsecr) ? 3 : 0;
+
+ rep.opt[offset++] = htonl((TCPOPT_AO << 24) |
+ (tcp_ao_len(ao_key) << 16) |
+ (ao_key->sndid << 8) | rcv_next);
+ arg.iov[0].iov_len += round_up(tcp_ao_len(ao_key), 4);
+ rep.th.doff = arg.iov[0].iov_len / 4;
+
+ tcp_ao_hash_hdr(AF_INET, (char *)&rep.opt[offset],
+ ao_key, traffic_key,
+ (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
+ (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
+ &rep.th, ao_sne);
+ }
+ WARN_ON_ONCE(key && ao_key);
#endif
arg.flags = reply_flags;
arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
@@ -999,6 +1017,32 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
{
struct inet_timewait_sock *tw = inet_twsk(sk);
struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
+ struct tcp_ao_key *ao_key = NULL;
+ u8 *traffic_key = NULL;
+ u8 rcv_next = 0;
+ u32 ao_sne = 0;
+#ifdef CONFIG_TCP_AO
+ struct tcp_ao_info *ao_info;
+
+ /* FIXME: the segment to-be-acked is not verified yet */
+ ao_info = rcu_dereference(tcptw->ao_info);
+ if (ao_info) {
+ const struct tcp_ao_hdr *aoh;
+
+ if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
+ goto out; /* something is wrong with the sign */
+
+ if (aoh)
+ ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1);
+ }
+ if (ao_key) {
+ struct tcp_ao_key *rnext_key;
+
+ traffic_key = snd_other_key(ao_key);
+ rnext_key = READ_ONCE(ao_info->rnext_key);
+ rcv_next = rnext_key->rcvid;
+ }
+#endif

tcp_v4_send_ack(sk, skb,
tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
@@ -1007,11 +1051,15 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
tcptw->tw_ts_recent,
tw->tw_bound_dev_if,
tcp_twsk_md5_key(tcptw),
+ ao_key, traffic_key, rcv_next, ao_sne,
tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
tw->tw_tos,
tw->tw_txhash
);

+#ifdef CONFIG_TCP_AO
+out:
+#endif
inet_twsk_put(tw);
}

@@ -1041,6 +1089,7 @@ static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
READ_ONCE(req->ts_recent),
0,
tcp_md5_do_lookup(sk, l3index, addr, AF_INET),
+ NULL, NULL, 0, 0,
inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
ip_hdr(skb)->tos,
READ_ONCE(tcp_rsk(req)->txhash));
@@ -2402,7 +2451,7 @@ void tcp_v4_destroy_sock(struct sock *sk)
rcu_assign_pointer(tp->md5sig_info, NULL);
}
#endif
- tcp_ao_destroy_sock(sk);
+ tcp_ao_destroy_sock(sk, false);

/* Clean up a referenced TCP bind bucket. */
if (inet_csk(sk)->icsk_bind_hash)
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 5616b6a34bee..3033f3187079 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -279,7 +279,7 @@ static void tcp_time_wait_init(struct sock *sk, struct tcp_timewait_sock *tcptw)
void tcp_time_wait(struct sock *sk, int state, int timeo)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
- const struct tcp_sock *tp = tcp_sk(sk);
+ struct tcp_sock *tp = tcp_sk(sk);
struct net *net = sock_net(sk);
struct inet_timewait_sock *tw;

@@ -316,6 +316,7 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
#endif

tcp_time_wait_init(sk, tcptw);
+ tcp_ao_time_wait(tcptw, tp);

/* Get the TIME_WAIT timeout firing. */
if (timeo < rto)
@@ -370,6 +371,7 @@ void tcp_twsk_destructor(struct sock *sk)
call_rcu(&twsk->tw_md5_key->rcu, tcp_md5_twsk_free_rcu);
}
#endif
+ tcp_ao_destroy_sock(sk, true);
}
EXPORT_SYMBOL_GPL(tcp_twsk_destructor);

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index a234c43727b2..f2d7671af811 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -4050,7 +4050,7 @@ int tcp_connect(struct sock *sk)
* then free up ao_info if allocated.
*/
if (needs_md5) {
- tcp_ao_destroy_sock(sk);
+ tcp_ao_destroy_sock(sk, false);
} else if (needs_ao) {
tcp_clear_md5_list(sk);
kfree(rcu_replace_pointer(tp->md5sig_info, NULL,
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 6f7651f26b03..9cb3fc40e682 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1137,24 +1137,57 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
struct tcp_md5sig_key *key, u8 tclass,
- __be32 label, u32 priority, u32 txhash)
+ __be32 label, u32 priority, u32 txhash,
+ struct tcp_ao_key *ao_key, char *tkey,
+ u8 rcv_next, u32 ao_sne)
{
tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
- tclass, label, priority, txhash, NULL, NULL, 0, 0);
+ tclass, label, priority, txhash,
+ ao_key, tkey, rcv_next, ao_sne);
}

static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
{
struct inet_timewait_sock *tw = inet_twsk(sk);
struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
+ struct tcp_ao_key *ao_key = NULL;
+ u8 *traffic_key = NULL;
+ u8 rcv_next = 0;
+ u32 ao_sne = 0;
+#ifdef CONFIG_TCP_AO
+ struct tcp_ao_info *ao_info;
+
+ /* FIXME: the segment to-be-acked is not verified yet */
+ ao_info = rcu_dereference(tcptw->ao_info);
+ if (ao_info) {
+ const struct tcp_ao_hdr *aoh;
+
+ /* Invalid TCP option size or twice included auth */
+ if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
+ goto out;
+ if (aoh)
+ ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1);
+ }
+ if (ao_key) {
+ struct tcp_ao_key *rnext_key;
+
+ traffic_key = snd_other_key(ao_key);
+ /* rcv_next switches to our rcv_next */
+ rnext_key = READ_ONCE(ao_info->rnext_key);
+ rcv_next = rnext_key->rcvid;
+ }
+#endif

tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
tcp_time_stamp_raw() + tcptw->tw_ts_offset,
tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel), tw->tw_priority,
- tw->tw_txhash);
+ tw->tw_txhash, ao_key, traffic_key, rcv_next, ao_sne);

+#ifdef CONFIG_TCP_AO
+out:
+#endif
inet_twsk_put(tw);
}

@@ -1181,7 +1214,7 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
READ_ONCE(req->ts_recent), sk->sk_bound_dev_if,
tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->saddr, l3index),
ipv6_get_dsfield(ipv6_hdr(skb)), 0, sk->sk_priority,
- READ_ONCE(tcp_rsk(req)->txhash));
+ READ_ONCE(tcp_rsk(req)->txhash), NULL, NULL, 0, 0);
}

--
2.41.0

Next message: Dmitry Safonov: "[PATCH v9 net-next 08/23] net/tcp: Add AO sign to RST packets"
Previous message: Dmitry Safonov: "[PATCH v9 net-next 07/23] net/tcp: Add tcp_parse_auth_options()"
In reply to: Dmitry Safonov: "[PATCH v9 net-next 07/23] net/tcp: Add tcp_parse_auth_options()"
Next in thread: Dmitry Safonov: "[PATCH v9 net-next 08/23] net/tcp: Add AO sign to RST packets"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]