Re: [PATCH] Bluetooth: HCI: Fix potential null-ptr-deref

From: Luiz Augusto von Dentz
Date: Thu May 02 2024 - 10:50:42 EST


Hi Sungwoo,

On Wed, May 1, 2024 at 10:22 PM Sungwoo Kim <iam@xxxxxxxxxxxx> wrote:
>
> Dear all,

Not sure if you are following what I actually enter as patch
description, that normally doesn't include things like Dear all, etc.

> hci_le_big_sync_established_evt() has a potential null-ptr-deref bug.
>
> hci_le_big_sync_established_evt()
> bis = hci_conn_hash_lookup_handle(hdev, handle);
> if (!bis)
> bis = hci_conn_add() <- could fail
> /* ... */
> bis = hci_conn_hash_lookup_handle(hdev, handle);
> set_bit(HCI_CONN_BIG_SYNC_FAILED, &bis->flags); <- null-ptr-deref
>
> There is a missing check after hci_conn_hash_lookup_handle(), which can
> return NULL. Especially, if a prior hci_conn_add() fails than
> hci_conn_hash_lookup_handle() will return NULL.
>
> This patch fixes this by adding a check.

Nor the one below.

> Thanks,
> Sungwoo.

And by now I'd expect you to start adding the Fixes tag as well.

> Signed-off-by: Sungwoo Kim <iam@xxxxxxxxxxxx>
> ---
> net/bluetooth/hci_event.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index 4a27e4a17..d72d238c1 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -7037,6 +7037,8 @@ static void hci_le_big_sync_established_evt(struct hci_dev *hdev, void *data,
> u16 handle = le16_to_cpu(ev->bis[i]);
>
> bis = hci_conn_hash_lookup_handle(hdev, handle);
> + if (!bis)
> + continue;
>
> set_bit(HCI_CONN_BIG_SYNC_FAILED, &bis->flags);
> hci_connect_cfm(bis, ev->status);
> --
> 2.34.1
>


--
Luiz Augusto von Dentz