Hi Luiz,
On Wed, Jul 3, 2024 at 10:25 AM Luiz Augusto von Dentz
<luiz.dentz@xxxxxxxxx> wrote:
>
> Hi,
>
> On Wed, Jul 3, 2024 at 7:40 AM Sungwoo Kim <iam@xxxxxxxxxxxx> wrote:
> >
> > KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077]
> > CPU: 1 PID: 2000 Comm: kworker/u9:5 Not tainted 6.9.0-ga6bcb805883c-dirty #10
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
> > Workqueue: hci7 hci_power_on
> > RIP: 0010:hci_read_supported_codecs+0xb9/0x870 net/bluetooth/hci_codec.c:138
> > Code: 08 48 89 ef e8 b8 c1 8f fd 48 8b 75 00 e9 96 00 00 00 49 89 c6 48 ba 00 00 00 00 00 fc ff df 4c 8d 60 70 4c 89 e3 48 c1 eb 03 <0f> b6 04 13 84 c0 0f 85 82 06 00 00 41 83 3c 24 02 77 0a e8 bf 78
> > RSP: 0018:ffff888120bafac8 EFLAGS: 00010212
> > RAX: 0000000000000000 RBX: 000000000000000e RCX: ffff8881173f0040
> > RDX: dffffc0000000000 RSI: ffffffffa58496c0 RDI: ffff88810b9ad1e4
> > RBP: ffff88810b9ac000 R08: ffffffffa77882a7 R09: 1ffffffff4ef1054
> > R10: dffffc0000000000 R11: fffffbfff4ef1055 R12: 0000000000000070
> > R13: 0000000000000000 R14: 0000000000000000 R15: ffff88810b9ac000
> > FS: 0000000000000000(0000) GS:ffff8881f6c00000(0000) knlGS:0000000000000000
> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f6ddaa3439e CR3: 0000000139764003 CR4: 0000000000770ef0
> > PKRU: 55555554
> > Call Trace:
> > <TASK>
> > hci_read_local_codecs_sync net/bluetooth/hci_sync.c:4546 [inline]
> > hci_init_stage_sync net/bluetooth/hci_sync.c:3441 [inline]
> > hci_init4_sync net/bluetooth/hci_sync.c:4706 [inline]
> > hci_init_sync net/bluetooth/hci_sync.c:4742 [inline]
> > hci_dev_init_sync net/bluetooth/hci_sync.c:4912 [inline]
> > hci_dev_open_sync+0x19a9/0x2d30 net/bluetooth/hci_sync.c:4994
> > hci_dev_do_open net/bluetooth/hci_core.c:483 [inline]
> > hci_power_on+0x11e/0x560 net/bluetooth/hci_core.c:1015
> > process_one_work kernel/workqueue.c:3267 [inline]
> > process_scheduled_works+0x8ef/0x14f0 kernel/workqueue.c:3348
> > worker_thread+0x91f/0xe50 kernel/workqueue.c:3429
> > kthread+0x2cb/0x360 kernel/kthread.c:388
> > ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
> > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
> >
> > Fixes: 8961987f3f5f ("Bluetooth: Enumerate local supported codec and cache details")
> > Fixes: 9ae664028a9e ("Bluetooth: Add support for Read Local Supported Codecs V2")
> >
> > Signed-off-by: Sungwoo Kim <iam@xxxxxxxxxxxx>
> > ---
> > net/bluetooth/hci_codec.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/net/bluetooth/hci_codec.c b/net/bluetooth/hci_codec.c
> > index 3cc135bb1..5c98eec2c 100644
> > --- a/net/bluetooth/hci_codec.c
> > +++ b/net/bluetooth/hci_codec.c
> > @@ -74,6 +74,9 @@ static void hci_read_codec_capabilities(struct hci_dev *hdev, __u8 transport,
> >
> > skb = __hci_cmd_sync_sk(hdev, HCI_OP_READ_LOCAL_CODEC_CAPS,
> > sizeof(*cmd), cmd, 0, HCI_CMD_TIMEOUT, NULL);
> > +
> > + if (!skb)
> > + skb = ERR_PTR(-EINVAL);
> > if (IS_ERR(skb)) {
> > bt_dev_err(hdev, "Failed to read codec capabilities (%ld)",
> > PTR_ERR(skb));
> > @@ -129,6 +132,8 @@ void hci_read_supported_codecs(struct hci_dev *hdev)
> > skb = __hci_cmd_sync_sk(hdev, HCI_OP_READ_LOCAL_CODECS, 0, NULL,
> > 0, HCI_CMD_TIMEOUT, NULL);
> >
> > + if (!skb)
> > + skb = ERR_PTR(-EINVAL);
> > if (IS_ERR(skb)) {
> > bt_dev_err(hdev, "Failed to read local supported codecs (%ld)",
> > PTR_ERR(skb));
> > @@ -198,6 +203,8 @@ void hci_read_supported_codecs_v2(struct hci_dev *hdev)
> > skb = __hci_cmd_sync_sk(hdev, HCI_OP_READ_LOCAL_CODECS_V2, 0, NULL,
> > 0, HCI_CMD_TIMEOUT, NULL);
> >
> > + if (!skb)
> > + skb = ERR_PTR(-EINVAL);
> > if (IS_ERR(skb)) {
> > bt_dev_err(hdev, "Failed to read local supported codecs (%ld)",
> > PTR_ERR(skb));
> > --
> > 2.34.1
>
>
> There is something that doesn't quite add here, we don't return NULL
> on __hci_cmd_sync_sk, if there is an error it will always return
The skb can be NULL if a command returns a status event as there are
no parameters.
> ERR_PTR or perhaps this is the result of rsp_skb being NULL in which
> case we shall check it and actually return ERR_PTR directly from
If returning NULL is not intended, we should also remove a NULL
checking in __hci_cmd_sync_status_sk().
We can do this:
https://gist.github.com/swkim101/5346b4ce5d2b1d4be95ef8dbdcbd9820
> __hci_cmd_sync_sk but Id like to understand under what circumstances
> does rsp_skb can be NULL.
>
>
> --
> Luiz Augusto von Dentz
>
Thanks,
Sungwoo.
