netdev - Re: [PATCH 1/1] NFC: Fix possible memory corruption when handling SHDLC I-Frame commands

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Message-ID: <CAJuCfpHSZuabLr6+t_n7UDamJCAP6EPTNEZ6kNqWOhk2mpYADg@mail.gmail.com>
Date:   Tue, 14 Aug 2018 13:26:04 -0700
From:   Suren Baghdasaryan <surenb@...gle.com>
To:     Dan Carpenter <dan.carpenter@...cle.com>
Cc:     security@...nel.org, Kevin Deus <kdeus@...gle.com>,
        Samuel Ortiz <sameo@...ux.intel.com>,
        "David S. Miller" <davem@...emloft.net>,
        Allen Pais <allen.pais@...cle.com>,
        Kees Cook <keescook@...omium.org>,
        linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] NFC: Fix possible memory corruption when handling
 SHDLC I-Frame commands

On Tue, Aug 14, 2018 at 9:57 AM, Suren Baghdasaryan <surenb@...gle.com> wrote:
> On Tue, Aug 14, 2018 at 2:54 AM, Dan Carpenter <dan.carpenter@...cle.com> wrote:
>> Thanks.  This is great.  I'm so glad these are finally getting fixed.
>>
>> Do we need to fix nfc_hci_msg_rx_work() and nfc_hci_recv_from_llc() as
>> well?  In nfc_hci_recv_from_llc() we allow pipe to be NFC_HCI_FRAGMENT
>> (0x7f) so that's one element beyond the end of the array and the
>> NFC_HCI_HCP_RESPONSE isn't checked.
>>
>> Also nci_hci_msg_rx_work() and nci_hci_data_received_cb() use
>> NCI_HCP_MSG_GET_PIPE() so those could be off by one.
>
> Good point. From hci.h:
>
> /*
>  * According to specification 102 622 chapter 4.4 Pipes,
>  * the pipe identifier is 7 bits long.
>  */
> #define NFC_HCI_MAX_PIPES 127
>
> And then:
>
> struct nfc_hci_dev {
>   ...
>   struct nfc_hci_pipe pipes[NFC_HCI_MAX_PIPES];
>   ...
> }
>
> I think the correct fix would be to change it to:
>
>   struct nfc_hci_pipe pipes[NFC_HCI_MAX_PIPES + 1];
>
> What do you think?
>

Just to be clear, this would fix the problem Dan described in his
reply and it should be implemented in a separate patch. The original
fix is still valid.

>>
>> regards,
>> dan carpenter
>>