Re: [PATCH 14/14] HID: i2c-hid: fix i2c_hid_get_raw_report count mismatches

From: Benjamin Tissoires
Date: Wed Dec 05 2012 - 05:39:55 EST


Hi,

sorry, but when I re-read it, it seems that I missed a +2 in the call
of i2c_hid_get_report.

So Jean, Jiri, please ignore this one. I'm really sorry if you already
started reviewing it.

I'll send a v2 with the missing patches early this afternoon.

Cheers,
Benjamin

On Tue, Dec 4, 2012 at 4:27 PM, Benjamin Tissoires
<benjamin.tissoires@xxxxxxxxx> wrote:
> The previous memcpy implementation relied on the size advertized by the
> device. There were no guarantees that buf was big enough.
>
> Some gymnastic is also required with the +2/-2 to take into account
> the first 2 bytes where the total length is supplied by the device.
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxx>
> ---
> drivers/hid/i2c-hid/i2c-hid.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index 62988f1..de3566f 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -503,13 +503,14 @@ static int i2c_hid_get_raw_report(struct hid_device *hid,
> {
> struct i2c_client *client = hid->driver_data;
> struct i2c_hid *ihid = i2c_get_clientdata(client);
> + size_t rcount;
> int ret;
>
> if (report_type == HID_OUTPUT_REPORT)
> return -EINVAL;
>
> - if (count > ihid->bufsize)
> - count = ihid->bufsize;
> + if (count > ihid->bufsize - 2)
> + count = ihid->bufsize - 2;
>
> ret = i2c_hid_get_report(client,
> report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
> @@ -518,7 +519,13 @@ static int i2c_hid_get_raw_report(struct hid_device *hid,
> if (ret < 0)
> return ret;
>
> - count = ihid->inbuf[0] | (ihid->inbuf[1] << 8);
> + rcount = ihid->inbuf[0] | (ihid->inbuf[1] << 8);
> +
> + if (!rcount)
> + return 0;
> +
> + if (count > rcount - 2)
> + count = rcount - 2;
>
> memcpy(buf, ihid->inbuf + 2, count);
>
> --
> 1.8.0.1
>
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