Re: [PATCH] nfc: fix memory leak of se_io context in nfc_genl_se_io

Krzysztof Kozlowski
2023-02-28T10:14:16Z

On 27/02/2023 16:05, Fedor Pchelkin wrote:
>>> Fixes: 5ce3f32b5264 ("NFC: netlink: SE API implementation")
>>> Reported-by: syzbot+df64c0a2e8d68e78a4fa@syzkaller.appspotmail.com
>>> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
>>> Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
>>
>> SoB order is a bit odd. Who is the author?
>>
>
> The author is me (Fedor). I thought the authorship is expressed with the
> first Signed-off-by line, isn't it?

Yes and since you are sending it, then what is Alexey's Sob for? The
tags are in order...

>
>>> ---
>>> drivers/nfc/st-nci/se.c | 6 ++++++
>>> drivers/nfc/st21nfca/se.c | 6 ++++++
>>> net/nfc/netlink.c | 4 ++++
>>> 3 files changed, 16 insertions(+)
>>>
>>> diff --git a/drivers/nfc/st-nci/se.c b/drivers/nfc/st-nci/se.c
>>> index ec87dd21e054..b2f1ced8e6dd 100644
>>> --- a/drivers/nfc/st-nci/se.c
>>> +++ b/drivers/nfc/st-nci/se.c
>>> @@ -672,6 +672,12 @@ int st_nci_se_io(struct nci_dev *ndev, u32 se_idx,
>>> ST_NCI_EVT_TRANSMIT_DATA, apdu,
>>> apdu_length)
>> nci_hci_send_event() should also free it in its error paths.
>> nci_data_exchange_complete() as well? Who eventually frees it? These
>> might be separate patches.
>>
>>
>
> nci_hci_send_event(), as I can see, should not free the callback context.
> I should have probably better explained that in the commit info (will
> include this in the patch v2), but the main thing is: nfc_se_io() is
> called with se_io_cb callback function as an argument and that callback is
> the exact place where an allocated se_io_ctx context should be freed. And
> it is actually freed there unless some error path happens that leads the

Exactly, so why nci_hci_send_event() error path should not free it?

> timer which triggers this se_io_cb callback not to be charged at all.
>

Best regards,
Krzysztof