2023-06-29 00:13:46

by Luiz Augusto von Dentz

[permalink] [raw]
Subject: [PATCH v4 3/3] Bluetooth: hci_conn: Always allocate unique handles

From: Luiz Augusto von Dentz <[email protected]>

This attempts to always allocate a unique handle for connections so they
can be properly aborted by the likes of hci_abort_conn, so this uses the
invalid range as a pool of unset handles that way if userspace is trying
to create multiple connections at once each will be given a unique
handle which will be considered unset.

Signed-off-by: Luiz Augusto von Dentz <[email protected]>
---
include/net/bluetooth/hci_core.h | 2 +-
net/bluetooth/hci_conn.c | 25 ++++++++++++++++++++++---
net/bluetooth/hci_event.c | 6 +++---
3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 094ca3aca15e..c0ca3f869c92 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -321,8 +321,8 @@ struct adv_monitor {

#define HCI_MAX_SHORT_NAME_LENGTH 10

-#define HCI_CONN_HANDLE_UNSET 0xffff
#define HCI_CONN_HANDLE_MAX 0x0eff
+#define HCI_CONN_HANDLE_UNSET(_handle) (_handle > HCI_CONN_HANDLE_MAX)

/* Min encryption key size to match with SMP */
#define HCI_MIN_ENC_KEY_SIZE 7
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 0b717989cd4f..83858e6b674c 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -932,6 +932,25 @@ static void cis_cleanup(struct hci_conn *conn)
hci_le_remove_cig(hdev, conn->iso_qos.ucast.cig);
}

+static u16 hci_conn_hash_alloc_unset(struct hci_dev *hdev)
+{
+ struct hci_conn_hash *h = &hdev->conn_hash;
+ struct hci_conn *c;
+ u16 handle = HCI_CONN_HANDLE_MAX + 1;
+
+ rcu_read_lock();
+
+ list_for_each_entry_rcu(c, &h->list, list) {
+ /* Find the first unused handle */
+ if (handle == 0xffff || c->handle != handle)
+ break;
+ handle++;
+ }
+ rcu_read_unlock();
+
+ return handle;
+}
+
struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
u8 role)
{
@@ -945,7 +964,7 @@ struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,

bacpy(&conn->dst, dst);
bacpy(&conn->src, &hdev->bdaddr);
- conn->handle = HCI_CONN_HANDLE_UNSET;
+ conn->handle = hci_conn_hash_alloc_unset(hdev);
conn->hdev = hdev;
conn->type = type;
conn->role = role;
@@ -1057,7 +1076,7 @@ static void hci_conn_unlink(struct hci_conn *conn)
*/
if ((child->type == SCO_LINK ||
child->type == ESCO_LINK) &&
- child->handle == HCI_CONN_HANDLE_UNSET)
+ HCI_CONN_HANDLE_UNSET(child->handle))
hci_conn_del(child);
}

@@ -1943,7 +1962,7 @@ int hci_conn_check_create_cis(struct hci_conn *conn)
return -EINVAL;

if (!conn->parent || conn->parent->state != BT_CONNECTED ||
- conn->state != BT_CONNECT || conn->handle == HCI_CONN_HANDLE_UNSET)
+ conn->state != BT_CONNECT || HCI_CONN_HANDLE_UNSET(conn->handle))
return 1;

return 0;
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 77cbf13037b3..0b4415e79989 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -3173,7 +3173,7 @@ static void hci_conn_complete_evt(struct hci_dev *hdev, void *data,
* As the connection handle is set here for the first time, it indicates
* whether the connection is already set up.
*/
- if (conn->handle != HCI_CONN_HANDLE_UNSET) {
+ if (!HCI_CONN_HANDLE_UNSET(conn->handle)) {
bt_dev_err(hdev, "Ignoring HCI_Connection_Complete for existing connection");
goto unlock;
}
@@ -5032,7 +5032,7 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev, void *data,
* As the connection handle is set here for the first time, it indicates
* whether the connection is already set up.
*/
- if (conn->handle != HCI_CONN_HANDLE_UNSET) {
+ if (!HCI_CONN_HANDLE_UNSET(conn->handle)) {
bt_dev_err(hdev, "Ignoring HCI_Sync_Conn_Complete event for existing connection");
goto unlock;
}
@@ -5896,7 +5896,7 @@ static void le_conn_complete_evt(struct hci_dev *hdev, u8 status,
* As the connection handle is set here for the first time, it indicates
* whether the connection is already set up.
*/
- if (conn->handle != HCI_CONN_HANDLE_UNSET) {
+ if (!HCI_CONN_HANDLE_UNSET(conn->handle)) {
bt_dev_err(hdev, "Ignoring HCI_Connection_Complete for existing connection");
goto unlock;
}
--
2.40.1