From: Antti Palosaari <crope@iki.fi>
To: Saso Slavicic <saso.linux@astim.si>, linux-media@vger.kernel.org
Subject: Re: ascot2e.c off by one bug
Date: Sat, 28 May 2016 13:11:02 +0300 [thread overview]
Message-ID: <424b5c9e-2019-76cc-5f2e-e68e43cfd6f8@iki.fi> (raw)
In-Reply-To: <000f01d1b8c3$54af4080$fe0dc180$@astim.si>
Convert it to regmap at the same (just a hint...)
On 05/28/2016 12:28 PM, Saso Slavicic wrote:
> Hi,
>
> Tuning a card with Sony ASCOT2E produces the following error:
>
> kernel: i2c i2c-9: wr reg=0006: len=11 is too big!
>
> MAX_WRITE_REGSIZE is defined as 10, buf[MAX_WRITE_REGSIZE + 1] buffer is
> used in ascot2e_write_regs().
>
> The problem is that exactly 10 bytes are written in ascot2e_set_params():
>
> /* Set BW_OFFSET (0x0F) value from parameter table */
> data[9] = ascot2e_sett[tv_system].bw_offset;
> ascot2e_write_regs(priv, 0x06, data, 10);
>
> The test in write_regs is as follows:
>
> if (len + 1 >= sizeof(buf))
>
> 10 + 1 = 11 and that would be exactly the size of buf. Since 10 bytes +
> buf[0] = reg would seem to fit into buf[], this shouldn't be an error.
>
> The following patch fixes the problem for me, I have tested the card and it
> seems to be working fine.
>
> ---
> drivers/media/dvb-frontends/ascot2e.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/media/dvb-frontends/ascot2e.c
> b/drivers/media/dvb-frontends/ascot2e.c
> --- a/drivers/media/dvb-frontends/ascot2e.c
> +++ b/drivers/media/dvb-frontends/ascot2e.c
> @@ -132,7 +132,7 @@ static int ascot2e_write_regs(struct ascot2e_priv *priv,
> }
> };
>
> - if (len + 1 >= sizeof(buf)) {
> + if (len + 1 > sizeof(buf)) {
> dev_warn(&priv->i2c->dev,"wr reg=%04x: len=%d is too
> big!\n",
> reg, len + 1);
> return -E2BIG;
>
> Regards,
> Saso Slavicic
>
>
> --
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--
http://palosaari.fi/
prev parent reply other threads:[~2016-05-28 10:11 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-28 9:28 ascot2e.c off by one bug Saso Slavicic
2016-05-28 10:11 ` Antti Palosaari [this message]
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