From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Jean Delvare <jdelvare@suse.de>
Cc: Linux I2C <linux-i2c@vger.kernel.org>
Subject: Re: i2c-tools: i2cbusses: Avoid buffer overflows in sysfs paths
Date: Mon, 6 Nov 2017 13:04:26 +0100 [thread overview]
Message-ID: <20171106120426.lyo6azbrxxok4gan@pengutronix.de> (raw)
In-Reply-To: <20171031081604.18a9ca54@endymion>
Hello Jean,
On Tue, Oct 31, 2017 at 08:16:04AM +0100, Jean Delvare wrote:
> sprintf isn't safe, use snprintf instead.
> ---
> tools/i2cbusses.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> --- a/tools/i2cbusses.c
> +++ b/tools/i2cbusses.c
> @@ -220,18 +220,18 @@ struct i2c_adap *gather_i2c_busses(void)
>
> /* this should work for kernels 2.6.5 or higher and */
> /* is preferred because is unambiguous */
> - sprintf(n, "%s/%s/name", sysfs, de->d_name);
> + snprintf(n, NAME_MAX, "%s/%s/name", sysfs, de->d_name);
OK, now instead of running in a buffer overflow in sprintf you might
call fopen with a partial (maybe unterminated?) filename. While this is
definitively better, you should check the return value of snprintf to be
completely safe here.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
next prev parent reply other threads:[~2017-11-06 12:04 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-31 7:16 i2c-tools: i2cbusses: Avoid buffer overflows in sysfs paths Jean Delvare
2017-11-06 12:04 ` Uwe Kleine-König [this message]
2017-11-08 8:57 ` Jean Delvare
2017-11-08 9:29 ` Uwe Kleine-König
2017-11-08 21:14 ` Jean Delvare
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