From: Guenter Roeck <linux@roeck-us.net>
To: Justin Stitt <justinstitt@google.com>
Cc: Jean Delvare <jdelvare@suse.com>,
linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH v3] hwmon: refactor deprecated strncpy
Date: Wed, 27 Sep 2023 05:48:56 -0700 [thread overview]
Message-ID: <9837d8dd-d802-4d5d-bca7-6e029658ba76@roeck-us.net> (raw)
In-Reply-To: <20230921-strncpy-drivers-hwmon-acpi_power_meter-c-v3-1-307552c6ec3f@google.com>
On Thu, Sep 21, 2023 at 05:41:46AM +0000, Justin Stitt wrote:
> `strncpy` is deprecated for use on NUL-terminated destination strings [1].
>
> Let's refactor this kcalloc() + strncpy() into a kmemdup_nul() which has
> more obvious behavior and is less error prone.
>
> To avoid truncating the last byte supply `...length + 1` to
> kmemdup_nul() as `element->string.length` does not account for the
> trailing null as made obvious from it's definition (and associated
> comment):
> | u32 length; /* # of bytes in string, excluding trailing null */
>
> ... this is precisely what the original kcalloc invocation did as well.
>
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
> Link: https://github.com/KSPP/linux/issues/90
> Cc: linux-hardening@vger.kernel.org
> Signed-off-by: Justin Stitt <justinstitt@google.com>
I have multiple patches with the hwmon: prefix but no driver,
like this one, suggesting the change is in the hwmon core,
when in reality it is in some hwmon driver.
I am not going to apply any of those, and I am not even going to
look into them.
Guenter
next prev parent reply other threads:[~2023-09-27 12:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-21 5:41 [PATCH v3] hwmon: refactor deprecated strncpy Justin Stitt
2023-09-24 3:18 ` Kees Cook
2023-09-27 12:48 ` Guenter Roeck [this message]
2023-09-27 14:05 ` Justin Stitt
2023-09-27 14:06 ` Justin Stitt
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