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From:   Amit Pundir <amit.pundir@linaro.org>
Date:   Mon, 23 Apr 2018 15:32:08 +0530
Message-ID: <CAMi1Hd24-Oc90CjyYrq2BRZD6S1fyZKDSVLTt1W68m7=cuKK=A@mail.gmail.com>
Subject: Re: [RESEND][PATCH 4/4] NFC: fdp: Fix possible buffer overflow in
 WCS4000 NFC driver
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     lkml <linux-kernel@vger.kernel.org>,
        linux-wireless@vger.kernel.org,
        Samuel Ortiz <sameo@linux.intel.com>,
        Christophe Ricard <christophe.ricard@gmail.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        John Stultz <john.stultz@linaro.org>,
        Dmitry Shmidt <dimitrysh@google.com>,
        Todd Kjos <tkjos@google.com>,
        Android Kernel Team <kernel-team@android.com>,
        Suren Baghdasaryan <surenb@google.com>
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On 23 April 2018 at 14:46, Greg KH <gregkh@linuxfoundation.org> wrote:
> On Wed, Apr 18, 2018 at 03:35:04PM +0530, Amit Pundir wrote:
>> From: Suren Baghdasaryan <surenb@google.com>
>>
>> Possible buffer overflow when reading next_read_size bytes into
>> tmp buffer after next_read_size was extracted from a previous packet.
>>
>> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
>> Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
>> ---
>>  drivers/nfc/fdp/i2c.c | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/nfc/fdp/i2c.c b/drivers/nfc/fdp/i2c.c
>> index c4da50e07bbc..08a4f82a2965 100644
>> --- a/drivers/nfc/fdp/i2c.c
>> +++ b/drivers/nfc/fdp/i2c.c
>> @@ -176,6 +176,16 @@ static int fdp_nci_i2c_read(struct fdp_i2c_phy *phy, struct sk_buff **skb)
>>               /* Packet that contains a length */
>>               if (tmp[0] == 0 && tmp[1] == 0) {
>>                       phy->next_read_size = (tmp[2] << 8) + tmp[3] + 3;
>> +                     /*
>> +                      * Ensure next_read_size does not exceed sizeof(tmp)
>> +                      * for reading that many bytes during next iteration
>> +                      */
>> +                     if (phy->next_read_size > FDP_NCI_I2C_MAX_PAYLOAD) {
>> +                             dev_dbg(&client->dev, "%s: corrupted packet\n",
>> +                                     __func__);
>
> As Andy points out, no need for __func__ in any dev_dbg() call.

Hi, Yes i'm working on v2 of this patch and on the comments I got on
another patch in this series.

Thanks,
Amit Pundir

>
> thanks,
>
> greg k-h