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net/tcp: Add static_key for TCP-AO 

Similarly to TCP-MD5, add a static key to TCP-AO that is patched out
when there are no keys on a machine and dynamically enabled with the
first setsockopt(TCP_AO) adds a key on any socket. The static key is as
well dynamically disabled later when the socket is destructed.

The lifetime of enabled static key here is the same as ao_info: it is
enabled on allocation, passed over from full socket to twsk and
destructed when ao_info is scheduled for destruction.

Signed-off-by: Dmitry Safonov <dima@arista.com>
Acked-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Dmitry Safonov 2023-10-23 20:22:12 +01:00 committed by David S. Miller
parent d6732b95b6
commit 67fa83f7c8
6 changed files with 98 additions and 46 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
include/net/tcp.h
View File

@ -2288,14 +2288,18 @@ static inline void tcp_get_current_key(const struct sock *sk,
#if defined(CONFIG_TCP_AO) || defined(CONFIG_TCP_MD5SIG)
const struct tcp_sock *tp = tcp_sk(sk);
#endif
#ifdef CONFIG_TCP_AO
struct tcp_ao_info *ao;
ao = rcu_dereference_protected(tp->ao_info, lockdep_sock_is_held(sk));
if (ao) {
out->ao_key = READ_ONCE(ao->current_key);
out->type = TCP_KEY_AO;
return;
#ifdef CONFIG_TCP_AO
if (static_branch_unlikely(&tcp_ao_needed.key)) {
struct tcp_ao_info *ao;
ao = rcu_dereference_protected(tp->ao_info,
lockdep_sock_is_held(sk));
if (ao) {
out->ao_key = READ_ONCE(ao->current_key);
out->type = TCP_KEY_AO;
return;
}
}
#endif
#ifdef CONFIG_TCP_MD5SIG
@ -2324,7 +2328,8 @@ static inline bool tcp_key_is_md5(const struct tcp_key *key)
static inline bool tcp_key_is_ao(const struct tcp_key *key)
{
#ifdef CONFIG_TCP_AO
if (key->type == TCP_KEY_AO)
if (static_branch_unlikely(&tcp_ao_needed.key) &&
key->type == TCP_KEY_AO)
return true;
#endif
return false;
@ -2718,6 +2723,9 @@ static inline bool tcp_ao_required(struct sock *sk, const void *saddr,
struct tcp_ao_info *ao_info;
struct tcp_ao_key *ao_key;
if (!static_branch_unlikely(&tcp_ao_needed.key))
return false;
ao_info = rcu_dereference_check(tcp_sk(sk)->ao_info,
lockdep_sock_is_held(sk));
if (!ao_info)

2
include/net/tcp_ao.h
View File

@ -151,6 +151,8 @@ do { \
#ifdef CONFIG_TCP_AO
/* TCP-AO structures and functions */
#include <linux/jump_label.h>
extern struct static_key_false_deferred tcp_ao_needed;
struct tcp4_ao_context {
__be32 saddr;

22
net/ipv4/tcp_ao.c
View File

@ -17,6 +17,8 @@
#include <net/ipv6.h>
#include <net/icmp.h>
DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_ao_needed, HZ);
int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx,
unsigned int len, struct tcp_sigpool *hp)
{
@ -50,6 +52,9 @@ bool tcp_ao_ignore_icmp(const struct sock *sk, int family, int type, int code)
bool ignore_icmp = false;
struct tcp_ao_info *ao;
if (!static_branch_unlikely(&tcp_ao_needed.key))
return false;
/* RFC5925, 7.8:
* >> A TCP-AO implementation MUST default to ignore incoming ICMPv4
* messages of Type 3 (destination unreachable), Codes 2-4 (protocol
@ -185,6 +190,9 @@ static struct tcp_ao_key *__tcp_ao_do_lookup(const struct sock *sk,
struct tcp_ao_key *key;
struct tcp_ao_info *ao;
if (!static_branch_unlikely(&tcp_ao_needed.key))
return NULL;
ao = rcu_dereference_check(tcp_sk(sk)->ao_info,
lockdep_sock_is_held(sk));
if (!ao)
@ -276,6 +284,7 @@ void tcp_ao_destroy_sock(struct sock *sk, bool twsk)
}
kfree_rcu(ao, rcu);
static_branch_slow_dec_deferred(&tcp_ao_needed);
}
void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp)
@ -1180,6 +1189,11 @@ int tcp_ao_copy_all_matching(const struct sock *sk, struct sock *newsk,
goto free_and_exit;
}
if (!static_key_fast_inc_not_disabled(&tcp_ao_needed.key.key)) {
ret = -EUSERS;
goto free_and_exit;
}
key_head = rcu_dereference(hlist_first_rcu(&new_ao->head));
first_key = hlist_entry_safe(key_head, struct tcp_ao_key, node);
@ -1607,6 +1621,10 @@ static int tcp_ao_add_cmd(struct sock *sk, unsigned short int family,
tcp_ao_link_mkt(ao_info, key);
if (first) {
if (!static_branch_inc(&tcp_ao_needed.key)) {
ret = -EUSERS;
goto err_free_sock;
}
sk_gso_disable(sk);
rcu_assign_pointer(tcp_sk(sk)->ao_info, ao_info);
}
@ -1875,6 +1893,10 @@ static int tcp_ao_info_cmd(struct sock *sk, unsigned short int family,
if (new_rnext)
WRITE_ONCE(ao_info->rnext_key, new_rnext);
if (first) {
if (!static_branch_inc(&tcp_ao_needed.key)) {
err = -EUSERS;
goto out;
}
sk_gso_disable(sk);
rcu_assign_pointer(tcp_sk(sk)->ao_info, ao_info);
}

46
net/ipv4/tcp_input.c
View File

@ -3572,41 +3572,55 @@ static inline bool tcp_may_update_window(const struct tcp_sock *tp,
(ack_seq == tp->snd_wl1 && (nwin > tp->snd_wnd || !nwin));
}
/* If we update tp->snd_una, also update tp->bytes_acked */
static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack)
static void tcp_snd_sne_update(struct tcp_sock *tp, u32 ack)
{
u32 delta = ack - tp->snd_una;
#ifdef CONFIG_TCP_AO
struct tcp_ao_info *ao;
#endif
sock_owned_by_me((struct sock *)tp);
tp->bytes_acked += delta;
#ifdef CONFIG_TCP_AO
if (!static_branch_unlikely(&tcp_ao_needed.key))
return;
ao = rcu_dereference_protected(tp->ao_info,
lockdep_sock_is_held((struct sock *)tp));
if (ao && ack < tp->snd_una)
ao->snd_sne++;
#endif
}
/* If we update tp->snd_una, also update tp->bytes_acked */
static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack)
{
u32 delta = ack - tp->snd_una;
sock_owned_by_me((struct sock *)tp);
tp->bytes_acked += delta;
tcp_snd_sne_update(tp, ack);
tp->snd_una = ack;
}
static void tcp_rcv_sne_update(struct tcp_sock *tp, u32 seq)
{
#ifdef CONFIG_TCP_AO
struct tcp_ao_info *ao;
if (!static_branch_unlikely(&tcp_ao_needed.key))
return;
ao = rcu_dereference_protected(tp->ao_info,
lockdep_sock_is_held((struct sock *)tp));
if (ao && seq < tp->rcv_nxt)
ao->rcv_sne++;
#endif
}
/* If we update tp->rcv_nxt, also update tp->bytes_received */
static void tcp_rcv_nxt_update(struct tcp_sock *tp, u32 seq)
{
u32 delta = seq - tp->rcv_nxt;
#ifdef CONFIG_TCP_AO
struct tcp_ao_info *ao;
#endif
sock_owned_by_me((struct sock *)tp);
tp->bytes_received += delta;
#ifdef CONFIG_TCP_AO
ao = rcu_dereference_protected(tp->ao_info,
lockdep_sock_is_held((struct sock *)tp));
if (ao && seq < tp->rcv_nxt)
ao->rcv_sne++;
#endif
tcp_rcv_sne_update(tp, seq);
WRITE_ONCE(tp->rcv_nxt, seq);
}

25
net/ipv4/tcp_ipv4.c
View File

@ -1024,18 +1024,20 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
#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 (static_branch_unlikely(&tcp_ao_needed.key)) {
/* 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)) {
inet_twsk_put(tw);
return;
if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) {
inet_twsk_put(tw);
return;
}
if (aoh)
key.ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1);
}
if (aoh)
key.ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1);
}
if (key.ao_key) {
struct tcp_ao_key *rnext_key;
@ -1081,7 +1083,8 @@ static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
tcp_sk(sk)->snd_nxt;
#ifdef CONFIG_TCP_AO
if (tcp_rsk_used_ao(req)) {
if (static_branch_unlikely(&tcp_ao_needed.key) &&
tcp_rsk_used_ao(req)) {
const union tcp_md5_addr *addr;
const struct tcp_ao_hdr *aoh;

25
net/ipv6/tcp_ipv6.c
View File

@ -1154,17 +1154,19 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
#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 (static_branch_unlikely(&tcp_ao_needed.key)) {
/* Invalid TCP option size or twice included auth */
if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
goto out;
if (aoh) {
key.ao_key = tcp_ao_established_key(ao_info,
aoh->rnext_keyid, -1);
/* 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)
key.ao_key = tcp_ao_established_key(ao_info,
aoh->rnext_keyid, -1);
}
}
if (key.ao_key) {
@ -1206,7 +1208,8 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
struct tcp_key key = {};
#ifdef CONFIG_TCP_AO
if (tcp_rsk_used_ao(req)) {
if (static_branch_unlikely(&tcp_ao_needed.key) &&
tcp_rsk_used_ao(req)) {
const struct in6_addr *addr = &ipv6_hdr(skb)->saddr;
const struct tcp_ao_hdr *aoh;
int l3index;