Re: [RESEND][PATCH 2/4] NFC: st21nfca: Fix memory OOB and leak issues in connectivity events handler

[Amit Pundir]

On 20 April 2018 at 18:09, Andy Shevchenko
<andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> On Wed, 2018-04-18 at 15:35 +0530, Amit Pundir wrote:
>
>>               if (skb->data[transaction->aid_len + 2] !=
>> -                 NFC_EVT_TRANSACTION_PARAMS_TAG)
>> +                 NFC_EVT_TRANSACTION_PARAMS_TAG ||
>> +                 skb->len < transaction->aid_len + transaction-
>> >params_len + 4) {
>
>> +                     devm_kfree(dev, transaction);
>
> Oh, no.
>
> This is not memory leak per se, this is bad choice of devm_ API where it
> should use plain kmalloc() / kfree().
>

Hi, If I switch to kmalloc()/kfree() with allocation and may be
pre-usage checks along the way up to nfc_genl_se_transaction() would
that suffice? I believe, I still be needing the additional aid_len and
params_len checks regardless, right?

Regards,
Amit Pundir

>>                       return -EPROTO;
>> +             }
>
> --
> Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Intel Finland Oy