From: Andrei Emeltchenko <andrei.emeltchenko@xxxxxxxxx>
Adding kref to l2cap_conn helps to better handle racing when deleting
l2cap_conn. Races are created when deleting conn from timeout and from
the other execution path.
Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@xxxxxxxxx>
---
include/net/bluetooth/l2cap.h | 6 ++
net/bluetooth/l2cap_core.c | 128 +++++++++++++++++++++++++++++++++--------
net/bluetooth/smp.c | 7 +--
3 files changed, 113 insertions(+), 28 deletions(-)
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 3d31ecd..5abfe8a 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -572,6 +572,8 @@ struct l2cap_conn {
struct list_head chan_l;
struct mutex chan_lock;
+
+ struct kref kref;
};
#define L2CAP_INFO_CL_MTU_REQ_SENT 0x01
@@ -779,5 +781,9 @@ void l2cap_chan_set_defaults(struct l2cap_chan *chan);
int l2cap_ertm_init(struct l2cap_chan *chan);
void l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan);
void l2cap_chan_del(struct l2cap_chan *chan, int err);
+void l2cap_conn_set_timer(struct l2cap_conn *conn, struct delayed_work *work,
+ long timeout);
+bool l2cap_conn_clear_timer(struct l2cap_conn *conn,
+ struct delayed_work *work);
#endif /* __L2CAP_H */
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 7aa862d..ee6ca78 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -57,6 +57,70 @@ static void l2cap_send_disconn_req(struct l2cap_conn *conn,
static void l2cap_tx(struct l2cap_chan *chan, struct l2cap_ctrl *control,
struct sk_buff_head *skbs, u8 event);
+static void l2cap_conn_del(struct hci_conn *hcon, int err);
+
+/* ---- L2CAP connections ---- */
+
+static void l2cap_conn_get(struct l2cap_conn *conn)
+{
+ BT_DBG("conn %p refcnt %d -> %d", conn,
+ atomic_read(&conn->kref.refcount),
+ atomic_read(&conn->kref.refcount) + 1);
+
+ kref_get(&conn->kref);
+}
+
+static void l2cap_conn_destroy(struct kref *kref)
+{
+ struct l2cap_conn *conn = container_of(kref, struct l2cap_conn, kref);
+
+ BT_DBG("conn %p", conn);
+
+ l2cap_conn_del(conn->hcon, 0);
+}
+
+static int l2cap_conn_put(struct l2cap_conn *conn)
+{
+ /* conn might be NULL, was checked before in l2cap_conn_del */
+ if (!conn) {
+ BT_DBG("conn == NULL");
+ return 1;
+ }
+
+ BT_DBG("conn %p refcnt %d -> %d", conn,
+ atomic_read(&conn->kref.refcount),
+ atomic_read(&conn->kref.refcount) - 1);
+
+ return kref_put(&conn->kref, &l2cap_conn_destroy);
+}
+
+void l2cap_conn_set_timer(struct l2cap_conn *conn, struct delayed_work *work,
+ long timeout)
+{
+ BT_DBG("conn %p timeout %ld", conn, timeout);
+
+ /* If delayed work cancelled do not hold(conn)
+ since it is already done with previous set_timer */
+ if (!cancel_delayed_work(work))
+ l2cap_conn_get(conn);
+
+ schedule_delayed_work(work, timeout);
+}
+
+bool l2cap_conn_clear_timer(struct l2cap_conn *conn, struct delayed_work *work)
+{
+ bool ret;
+
+ BT_DBG("conn %p", conn);
+
+ /* put(conn) if delayed work cancelled otherwise it
+ is done in delayed work function */
+ ret = cancel_delayed_work(work);
+ if (ret)
+ l2cap_conn_put(conn);
+
+ return ret;
+}
/* ---- L2CAP channels ---- */
@@ -997,7 +1061,8 @@ static void l2cap_do_start(struct l2cap_chan *chan)
conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_SENT;
conn->info_ident = l2cap_get_ident(conn);
- schedule_delayed_work(&conn->info_timer, L2CAP_INFO_TIMEOUT);
+ l2cap_conn_set_timer(conn, &conn->info_timer,
+ L2CAP_INFO_TIMEOUT);
l2cap_send_cmd(conn, conn->info_ident,
L2CAP_INFO_REQ, sizeof(req), &req);
@@ -1279,12 +1344,14 @@ static void l2cap_conn_unreliable(struct l2cap_conn *conn, int err)
static void l2cap_info_timeout(struct work_struct *work)
{
struct l2cap_conn *conn = container_of(work, struct l2cap_conn,
- info_timer.work);
+ info_timer.work);
conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_DONE;
conn->info_ident = 0;
l2cap_conn_start(conn);
+
+ l2cap_conn_put(conn);
}
static void l2cap_conn_del(struct hci_conn *hcon, int err)
@@ -1318,13 +1385,8 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err)
hci_chan_del(conn->hchan);
- if (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_SENT)
- cancel_delayed_work_sync(&conn->info_timer);
-
- if (test_and_clear_bit(HCI_CONN_LE_SMP_PEND, &hcon->flags)) {
- cancel_delayed_work_sync(&conn->security_timer);
+ if (test_and_clear_bit(HCI_CONN_LE_SMP_PEND, &hcon->flags))
smp_chan_destroy(conn);
- }
hcon->l2cap_data = NULL;
kfree(conn);
@@ -1333,14 +1395,11 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err)
static void security_timeout(struct work_struct *work)
{
struct l2cap_conn *conn = container_of(work, struct l2cap_conn,
- security_timer.work);
+ security_timer.work);
BT_DBG("conn %p", conn);
- if (test_and_clear_bit(HCI_CONN_LE_SMP_PEND, &conn->hcon->flags)) {
- smp_chan_destroy(conn);
- l2cap_conn_del(conn->hcon, ETIMEDOUT);
- }
+ l2cap_conn_put(conn);
}
static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status)
@@ -1382,6 +1441,8 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status)
INIT_LIST_HEAD(&conn->chan_l);
+ kref_init(&conn->kref);
+
if (hcon->type == LE_LINK)
INIT_DELAYED_WORK(&conn->security_timer, security_timeout);
else
@@ -3337,8 +3398,8 @@ static inline int l2cap_command_rej(struct l2cap_conn *conn, struct l2cap_cmd_hd
return 0;
if ((conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_SENT) &&
- cmd->ident == conn->info_ident) {
- cancel_delayed_work(&conn->info_timer);
+ cmd->ident == conn->info_ident) {
+ l2cap_conn_clear_timer(conn, &conn->info_timer);
conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_DONE;
conn->info_ident = 0;
@@ -3452,10 +3513,11 @@ sendresp:
conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_SENT;
conn->info_ident = l2cap_get_ident(conn);
- schedule_delayed_work(&conn->info_timer, L2CAP_INFO_TIMEOUT);
+ l2cap_conn_set_timer(conn, &conn->info_timer,
+ L2CAP_INFO_TIMEOUT);
l2cap_send_cmd(conn, conn->info_ident,
- L2CAP_INFO_REQ, sizeof(info), &info);
+ L2CAP_INFO_REQ, sizeof(info), &info);
}
if (chan && !test_bit(CONF_REQ_SENT, &chan->conf_state) &&
@@ -3908,7 +3970,7 @@ static inline int l2cap_information_rsp(struct l2cap_conn *conn, struct l2cap_cm
conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_DONE)
return 0;
- cancel_delayed_work(&conn->info_timer);
+ l2cap_conn_clear_timer(conn, &conn->info_timer);
if (result != L2CAP_IR_SUCCESS) {
conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_DONE;
@@ -5291,8 +5353,10 @@ static void l2cap_recv_frame(struct l2cap_conn *conn, struct sk_buff *skb)
break;
case L2CAP_CID_SMP:
- if (smp_sig_channel(conn, skb))
- l2cap_conn_del(conn->hcon, EACCES);
+ if (smp_sig_channel(conn, skb)) {
+ l2cap_conn_clear_timer(conn, &conn->security_timer);
+ l2cap_conn_put(conn);
+ }
break;
default:
@@ -5344,8 +5408,14 @@ int l2cap_connect_cfm(struct hci_conn *hcon, u8 status)
conn = l2cap_conn_add(hcon, status);
if (conn)
l2cap_conn_ready(conn);
- } else
- l2cap_conn_del(hcon, bt_to_errno(status));
+ } else {
+ conn = hcon->l2cap_data;
+
+ if (hcon->type == LE_LINK)
+ l2cap_conn_clear_timer(conn, &conn->security_timer);
+
+ l2cap_conn_put(conn);
+ }
return 0;
}
@@ -5363,9 +5433,14 @@ int l2cap_disconn_ind(struct hci_conn *hcon)
int l2cap_disconn_cfm(struct hci_conn *hcon, u8 reason)
{
+ struct l2cap_conn *conn = hcon->l2cap_data;
BT_DBG("hcon %p reason %d", hcon, reason);
- l2cap_conn_del(hcon, bt_to_errno(reason));
+ if (hcon->type == LE_LINK)
+ l2cap_conn_clear_timer(conn, &conn->security_timer);
+
+ l2cap_conn_put(conn);
+
return 0;
}
@@ -5395,10 +5470,13 @@ int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
BT_DBG("conn %p", conn);
+ l2cap_conn_get(conn);
+
if (hcon->type == LE_LINK) {
if (!status && encrypt)
smp_distribute_keys(conn, 0);
- cancel_delayed_work(&conn->security_timer);
+
+ l2cap_conn_clear_timer(conn, &conn->security_timer);
}
mutex_lock(&conn->chan_lock);
@@ -5497,6 +5575,8 @@ int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
mutex_unlock(&conn->chan_lock);
+ l2cap_conn_put(conn);
+
return 0;
}
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 16ef0dc..5bb5b51 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -186,8 +186,7 @@ static void smp_send_cmd(struct l2cap_conn *conn, u8 code, u16 len, void *data)
skb->priority = HCI_PRIO_MAX;
hci_send_acl(conn->hchan, skb, 0);
- cancel_delayed_work_sync(&conn->security_timer);
- schedule_delayed_work(&conn->security_timer, SMP_TIMEOUT);
+ l2cap_conn_set_timer(conn, &conn->security_timer, SMP_TIMEOUT);
}
static __u8 authreq_to_seclevel(__u8 authreq)
@@ -268,7 +267,7 @@ static void smp_failure(struct l2cap_conn *conn, u8 reason, u8 send)
hcon->dst_type, reason);
if (test_and_clear_bit(HCI_CONN_LE_SMP_PEND, &conn->hcon->flags)) {
- cancel_delayed_work_sync(&conn->security_timer);
+ l2cap_conn_clear_timer(conn, &conn->security_timer);
smp_chan_destroy(conn);
}
}
@@ -999,7 +998,7 @@ int smp_distribute_keys(struct l2cap_conn *conn, __u8 force)
if (conn->hcon->out || force) {
clear_bit(HCI_CONN_LE_SMP_PEND, &conn->hcon->flags);
- cancel_delayed_work_sync(&conn->security_timer);
+ l2cap_conn_clear_timer(conn, &conn->security_timer);
smp_chan_destroy(conn);
}
--
1.7.9.5
--
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