[PATCH 4.4 14/32] AX.25: Close socket connection on session completion

From: Greg Kroah-Hartman
Date: Wed Jul 06 2016 - 21:26:41 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Basil Gunn <basil@xxxxxxxxxxxxx>

[ Upstream commit 4a7d99ea1b27734558feb6833f180cd38a159940 ]

A socket connection made in ax.25 is not closed when session is
completed. The heartbeat timer is stopped prematurely and this is
where the socket gets closed. Allow heatbeat timer to run to close
socket. Symptom occurs in kernels >= 4.2.0

Originally sent 6/15/2016. Resend with distribution list matching
scripts/maintainer.pl output.

Signed-off-by: Basil Gunn <basil@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ax25/af_ax25.c | 3 ++-
net/ax25/ax25_ds_timer.c | 5 ++++-
net/ax25/ax25_std_timer.c | 5 ++++-
net/ax25/ax25_subr.c | 3 ++-
4 files changed, 12 insertions(+), 4 deletions(-)

--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -976,7 +976,8 @@ static int ax25_release(struct socket *s
release_sock(sk);
ax25_disconnect(ax25, 0);
lock_sock(sk);
- ax25_destroy_socket(ax25);
+ if (!sock_flag(ax25->sk, SOCK_DESTROY))
+ ax25_destroy_socket(ax25);
break;

case AX25_STATE_3:
--- a/net/ax25/ax25_ds_timer.c
+++ b/net/ax25/ax25_ds_timer.c
@@ -102,6 +102,7 @@ void ax25_ds_heartbeat_expiry(ax25_cb *a
switch (ax25->state) {

case AX25_STATE_0:
+ case AX25_STATE_2:
/* Magic here: If we listen() and a new link dies before it
is accepted() it isn't 'dead' so doesn't get removed. */
if (!sk || sock_flag(sk, SOCK_DESTROY) ||
@@ -111,6 +112,7 @@ void ax25_ds_heartbeat_expiry(ax25_cb *a
sock_hold(sk);
ax25_destroy_socket(ax25);
bh_unlock_sock(sk);
+ /* Ungrab socket and destroy it */
sock_put(sk);
} else
ax25_destroy_socket(ax25);
@@ -213,7 +215,8 @@ void ax25_ds_t1_timeout(ax25_cb *ax25)
case AX25_STATE_2:
if (ax25->n2count == ax25->n2) {
ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
- ax25_disconnect(ax25, ETIMEDOUT);
+ if (!sock_flag(ax25->sk, SOCK_DESTROY))
+ ax25_disconnect(ax25, ETIMEDOUT);
return;
} else {
ax25->n2count++;
--- a/net/ax25/ax25_std_timer.c
+++ b/net/ax25/ax25_std_timer.c
@@ -38,6 +38,7 @@ void ax25_std_heartbeat_expiry(ax25_cb *

switch (ax25->state) {
case AX25_STATE_0:
+ case AX25_STATE_2:
/* Magic here: If we listen() and a new link dies before it
is accepted() it isn't 'dead' so doesn't get removed. */
if (!sk || sock_flag(sk, SOCK_DESTROY) ||
@@ -47,6 +48,7 @@ void ax25_std_heartbeat_expiry(ax25_cb *
sock_hold(sk);
ax25_destroy_socket(ax25);
bh_unlock_sock(sk);
+ /* Ungrab socket and destroy it */
sock_put(sk);
} else
ax25_destroy_socket(ax25);
@@ -144,7 +146,8 @@ void ax25_std_t1timer_expiry(ax25_cb *ax
case AX25_STATE_2:
if (ax25->n2count == ax25->n2) {
ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
- ax25_disconnect(ax25, ETIMEDOUT);
+ if (!sock_flag(ax25->sk, SOCK_DESTROY))
+ ax25_disconnect(ax25, ETIMEDOUT);
return;
} else {
ax25->n2count++;
--- a/net/ax25/ax25_subr.c
+++ b/net/ax25/ax25_subr.c
@@ -264,7 +264,8 @@ void ax25_disconnect(ax25_cb *ax25, int
{
ax25_clear_queues(ax25);

- ax25_stop_heartbeat(ax25);
+ if (!sock_flag(ax25->sk, SOCK_DESTROY))
+ ax25_stop_heartbeat(ax25);
ax25_stop_t1timer(ax25);
ax25_stop_t2timer(ax25);
ax25_stop_t3timer(ax25);