[PATCH] bluetooth: fix uninitialized variables notify_evt

From: Jackie Liu <redacted>

Coverity Scan report:

[...]
*** CID 1493985:  Uninitialized variables  (UNINIT)
/net/bluetooth/hci_event.c: 4535 in hci_sync_conn_complete_evt()
4529
4530     	/* Notify only in case of SCO over HCI transport data path which
4531     	 * is zero and non-zero value shall be non-HCI transport data path
4532     	 */
4533     	if (conn->codec.data_path == 0) {
4534     		if (hdev->notify)

quoted

quoted

    CID 1493985:  Uninitialized variables  (UNINIT)
    Using uninitialized value "notify_evt" when calling "*hdev->notify".

4535     			hdev->notify(hdev, notify_evt);
4536     	}
4537
4538     	hci_connect_cfm(conn, ev->status);
4539     	if (ev->status)
4540     		hci_conn_del(conn);
[...]

Although only btusb uses air_mode, and he only handles HCI_NOTIFY_ENABLE_SCO_CVSD
and HCI_NOTIFY_ENABLE_SCO_TRANSP, there is still a very small chance that
ev->air_mode is not equal to 0x2 and 0x3, but notify_evt is initialized to
HCI_NOTIFY_ENABLE_SCO_CVSD or HCI_NOTIFY_ENABLE_SCO_TRANSP. the context is
maybe not correct.

In order to ensure 100% correctness, we directly give him a default value 0.

Addresses-Coverity: ("Uninitialized variables")
Fixes: f4f9fa0c07bb ("Bluetooth: Allow usb to auto-suspend when SCO use	non-HCI transport")
Signed-off-by: Jackie Liu <redacted>
---
 net/bluetooth/hci_event.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 7d0db1ca1248..f898fa42a183 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c

@@ -4445,7 +4445,7 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,
 {
 	struct hci_ev_sync_conn_complete *ev = (void *) skb->data;
 	struct hci_conn *conn;
-	unsigned int notify_evt;
+	unsigned int notify_evt = 0;
 
 	BT_DBG("%s status 0x%2.2x", hdev->name, ev->status);
 

-- 
2.25.1

Hi Jackie,

lets modify the switch statement and add a default case. And then lets add a check to notify_evt != 0.

With that in mind, I wonder if this is not better

        /* Notify only in case of SCO over HCI transport data path which
         * is zero and non-zero value shall be non-HCI transport data path
         */ 
	if (conn->codec.data_path == 0 && hdev->notify) {
		switch (ev->air_mode) {
		case 0x02:
			hdev->notify(hdev, HCI_NOTIFY_ENABLE_SCO_CVSD);
			break;
		case 0x03:
			hdev->notify(hdev, HCI_NOTIFY_ENABLE_SCO_TRANSP);
			break;
		}
	}

Regards

Marcel

Hi, Marcel.

在 2021/11/16 上午1:27, Marcel Holtmann 写道:

Hi Jackie,

quoted

Coverity Scan report:

[...]
*** CID 1493985:  Uninitialized variables  (UNINIT)
/net/bluetooth/hci_event.c: 4535 in hci_sync_conn_complete_evt()
4529
4530     	/* Notify only in case of SCO over HCI transport data path which
4531     	 * is zero and non-zero value shall be non-HCI transport data path
4532     	 */
4533     	if (conn->codec.data_path == 0) {
4534     		if (hdev->notify)

quoted

quoted

quoted

    CID 1493985:  Uninitialized variables  (UNINIT)
    Using uninitialized value "notify_evt" when calling "*hdev->notify".

4535     			hdev->notify(hdev, notify_evt);
4536     	}
4537
4538     	hci_connect_cfm(conn, ev->status);
4539     	if (ev->status)
4540     		hci_conn_del(conn);
[...]

Although only btusb uses air_mode, and he only handles HCI_NOTIFY_ENABLE_SCO_CVSD
and HCI_NOTIFY_ENABLE_SCO_TRANSP, there is still a very small chance that
ev->air_mode is not equal to 0x2 and 0x3, but notify_evt is initialized to
HCI_NOTIFY_ENABLE_SCO_CVSD or HCI_NOTIFY_ENABLE_SCO_TRANSP. the context is
maybe not correct.

In order to ensure 100% correctness, we directly give him a default value 0.

Addresses-Coverity: ("Uninitialized variables")
Fixes: f4f9fa0c07bb ("Bluetooth: Allow usb to auto-suspend when SCO use	non-HCI transport")
Signed-off-by: Jackie Liu <redacted>
---
net/bluetooth/hci_event.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 7d0db1ca1248..f898fa42a183 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c

@@ -4445,7 +4445,7 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,

{
	struct hci_ev_sync_conn_complete *ev = (void *) skb->data;
	struct hci_conn *conn;
-	unsigned int notify_evt;
+	unsigned int notify_evt = 0;

	BT_DBG("%s status 0x%2.2x", hdev->name, ev->status);

lets modify the switch statement and add a default case. And then lets add a check to notify_evt != 0.

With that in mind, I wonder if this is not better

         /* Notify only in case of SCO over HCI transport data path which
          * is zero and non-zero value shall be non-HCI transport data path
          */
	if (conn->codec.data_path == 0 && hdev->notify) {
		switch (ev->air_mode) {
		case 0x02:
			hdev->notify(hdev, HCI_NOTIFY_ENABLE_SCO_CVSD);
			break;
		case 0x03:
			hdev->notify(hdev, HCI_NOTIFY_ENABLE_SCO_TRANSP);
			break;
		}
	}

I prefer this, because it is a restoration of earlier logic, rather than
changing his logic. I will resend a patch, thank you.

--
Jackie Liu

Regards

Marcel