2021-11-15 08:57:29

by Jackie Liu

Subject: [PATCH] bluetooth: fix uninitialized variables notify_evt

From: Jackie Liu <[email protected]>

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)
>>> 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 <[email protected]>
---
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

2021-11-15 17:29:47

by Marcel Holtmann

Subject: Re: [PATCH] bluetooth: fix uninitialized variables notify_evt

Hi Jackie,

> 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)
>>>> 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 <[email protected]>
> ---
> 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;
}
}

Regards

Marcel

2021-11-16 00:49:38

by Jackie Liu

Subject: Re: [PATCH] bluetooth: fix uninitialized variables notify_evt

Hi, Marcel.

?? 2021/11/16 ????1:27, Marcel Holtmann д??:
> Hi Jackie,
>
>> 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)
>>>>> 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 <[email protected]>
>> ---
>> 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
>