kernel_optimize_test/net/netrom/nr_timer.c
Nguyen Dinh Phi 6811744bd0 netrom: Decrease sock refcount when sock timers expire
[ Upstream commit 517a16b1a88bdb6b530f48d5d153478b2552d9a8 ]

Commit 63346650c1 ("netrom: switch to sock timer API") switched to use
sock timer API. It replaces mod_timer() by sk_reset_timer(), and
del_timer() by sk_stop_timer().

Function sk_reset_timer() will increase the refcount of sock if it is
called on an inactive timer, hence, in case the timer expires, we need to
decrease the refcount ourselves in the handler, otherwise, the sock
refcount will be unbalanced and the sock will never be freed.

Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
Reported-by: syzbot+10f1194569953b72f1ae@syzkaller.appspotmail.com
Fixes: 63346650c1 ("netrom: switch to sock timer API")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-28 14:35:38 +02:00

248 lines
5.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
*
* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
* Copyright (C) 2002 Ralf Baechle DO1GRB (ralf@gnu.org)
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <linux/uaccess.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <net/netrom.h>
static void nr_heartbeat_expiry(struct timer_list *);
static void nr_t1timer_expiry(struct timer_list *);
static void nr_t2timer_expiry(struct timer_list *);
static void nr_t4timer_expiry(struct timer_list *);
static void nr_idletimer_expiry(struct timer_list *);
void nr_init_timers(struct sock *sk)
{
struct nr_sock *nr = nr_sk(sk);
timer_setup(&nr->t1timer, nr_t1timer_expiry, 0);
timer_setup(&nr->t2timer, nr_t2timer_expiry, 0);
timer_setup(&nr->t4timer, nr_t4timer_expiry, 0);
timer_setup(&nr->idletimer, nr_idletimer_expiry, 0);
/* initialized by sock_init_data */
sk->sk_timer.function = nr_heartbeat_expiry;
}
void nr_start_t1timer(struct sock *sk)
{
struct nr_sock *nr = nr_sk(sk);
sk_reset_timer(sk, &nr->t1timer, jiffies + nr->t1);
}
void nr_start_t2timer(struct sock *sk)
{
struct nr_sock *nr = nr_sk(sk);
sk_reset_timer(sk, &nr->t2timer, jiffies + nr->t2);
}
void nr_start_t4timer(struct sock *sk)
{
struct nr_sock *nr = nr_sk(sk);
sk_reset_timer(sk, &nr->t4timer, jiffies + nr->t4);
}
void nr_start_idletimer(struct sock *sk)
{
struct nr_sock *nr = nr_sk(sk);
if (nr->idle > 0)
sk_reset_timer(sk, &nr->idletimer, jiffies + nr->idle);
}
void nr_start_heartbeat(struct sock *sk)
{
sk_reset_timer(sk, &sk->sk_timer, jiffies + 5 * HZ);
}
void nr_stop_t1timer(struct sock *sk)
{
sk_stop_timer(sk, &nr_sk(sk)->t1timer);
}
void nr_stop_t2timer(struct sock *sk)
{
sk_stop_timer(sk, &nr_sk(sk)->t2timer);
}
void nr_stop_t4timer(struct sock *sk)
{
sk_stop_timer(sk, &nr_sk(sk)->t4timer);
}
void nr_stop_idletimer(struct sock *sk)
{
sk_stop_timer(sk, &nr_sk(sk)->idletimer);
}
void nr_stop_heartbeat(struct sock *sk)
{
sk_stop_timer(sk, &sk->sk_timer);
}
int nr_t1timer_running(struct sock *sk)
{
return timer_pending(&nr_sk(sk)->t1timer);
}
static void nr_heartbeat_expiry(struct timer_list *t)
{
struct sock *sk = from_timer(sk, t, sk_timer);
struct nr_sock *nr = nr_sk(sk);
bh_lock_sock(sk);
switch (nr->state) {
case NR_STATE_0:
/* Magic here: If we listen() and a new link dies before it
is accepted() it isn't 'dead' so doesn't get removed. */
if (sock_flag(sk, SOCK_DESTROY) ||
(sk->sk_state == TCP_LISTEN && sock_flag(sk, SOCK_DEAD))) {
bh_unlock_sock(sk);
nr_destroy_socket(sk);
goto out;
}
break;
case NR_STATE_3:
/*
* Check for the state of the receive buffer.
*/
if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf / 2) &&
(nr->condition & NR_COND_OWN_RX_BUSY)) {
nr->condition &= ~NR_COND_OWN_RX_BUSY;
nr->condition &= ~NR_COND_ACK_PENDING;
nr->vl = nr->vr;
nr_write_internal(sk, NR_INFOACK);
break;
}
break;
}
nr_start_heartbeat(sk);
bh_unlock_sock(sk);
out:
sock_put(sk);
}
static void nr_t2timer_expiry(struct timer_list *t)
{
struct nr_sock *nr = from_timer(nr, t, t2timer);
struct sock *sk = &nr->sock;
bh_lock_sock(sk);
if (nr->condition & NR_COND_ACK_PENDING) {
nr->condition &= ~NR_COND_ACK_PENDING;
nr_enquiry_response(sk);
}
bh_unlock_sock(sk);
sock_put(sk);
}
static void nr_t4timer_expiry(struct timer_list *t)
{
struct nr_sock *nr = from_timer(nr, t, t4timer);
struct sock *sk = &nr->sock;
bh_lock_sock(sk);
nr_sk(sk)->condition &= ~NR_COND_PEER_RX_BUSY;
bh_unlock_sock(sk);
sock_put(sk);
}
static void nr_idletimer_expiry(struct timer_list *t)
{
struct nr_sock *nr = from_timer(nr, t, idletimer);
struct sock *sk = &nr->sock;
bh_lock_sock(sk);
nr_clear_queues(sk);
nr->n2count = 0;
nr_write_internal(sk, NR_DISCREQ);
nr->state = NR_STATE_2;
nr_start_t1timer(sk);
nr_stop_t2timer(sk);
nr_stop_t4timer(sk);
sk->sk_state = TCP_CLOSE;
sk->sk_err = 0;
sk->sk_shutdown |= SEND_SHUTDOWN;
if (!sock_flag(sk, SOCK_DEAD)) {
sk->sk_state_change(sk);
sock_set_flag(sk, SOCK_DEAD);
}
bh_unlock_sock(sk);
sock_put(sk);
}
static void nr_t1timer_expiry(struct timer_list *t)
{
struct nr_sock *nr = from_timer(nr, t, t1timer);
struct sock *sk = &nr->sock;
bh_lock_sock(sk);
switch (nr->state) {
case NR_STATE_1:
if (nr->n2count == nr->n2) {
nr_disconnect(sk, ETIMEDOUT);
goto out;
} else {
nr->n2count++;
nr_write_internal(sk, NR_CONNREQ);
}
break;
case NR_STATE_2:
if (nr->n2count == nr->n2) {
nr_disconnect(sk, ETIMEDOUT);
goto out;
} else {
nr->n2count++;
nr_write_internal(sk, NR_DISCREQ);
}
break;
case NR_STATE_3:
if (nr->n2count == nr->n2) {
nr_disconnect(sk, ETIMEDOUT);
goto out;
} else {
nr->n2count++;
nr_requeue_frames(sk);
}
break;
}
nr_start_t1timer(sk);
out:
bh_unlock_sock(sk);
sock_put(sk);
}