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

[Suren Baghdasaryan]

On Tue, Aug 14, 2018 at 2:54 AM, Dan Carpenter <dan.carpenter@xxxxxxxxxx> 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?

>
> regards,
> dan carpenter
>