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Date:   Wed, 27 Sep 2023 12:43:46 +0200
From:   Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
To:     Justin Stitt <justinstitt@google.com>
Cc:     David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2] drm/gma500: refactor deprecated strncpy
Message-ID: <fmvdws32xrjj3a3vqwcghnniojcglrpzs4mk5cw67vog6vlwta@zmoz6bv2i5iw>
Mail-Followup-To: Justin Stitt <justinstitt@google.com>, 
        David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>, dri-devel@lists.freedesktop.org, 
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
References: <20230919-drivers-gpu-drm-gma500-oaktrail_lvds_i2c-c-v2-1-9ebe6983b4cb@google.com>
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In-Reply-To: <20230919-drivers-gpu-drm-gma500-oaktrail_lvds_i2c-c-v2-1-9ebe6983b4cb@google.com>
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On Tue, Sep 19, 2023 at 04:41:16AM +0000, Justin Stitt wrote:
> `strncpy` is deprecated for use on NUL-terminated destination strings [1].
> 
> We should prefer more robust and less ambiguous string interfaces.
> 
> Since `chan->base.name` is expected to be NUL-terminated, a suitable
> replacement is `strscpy` [2] due to the fact that it guarantees
> NUL-termination on the destination buffer without also unnecessarily
> NUL-padding (since `chan` is kzalloc'd already).
> 
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
> Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
> Link: https://github.com/KSPP/linux/issues/90
> Cc: linux-hardening@vger.kernel.org
> Signed-off-by: Justin Stitt <justinstitt@google.com>

Applied to drm-misc-next.

Thanks
Patrik

> ---
> Changes in v2:
> - use sizeof() instead of I2C_NAME_SIZE (thanks Kees, Patrik)
> - Link to v1: https://lore.kernel.org/r/20230914-drivers-gpu-drm-gma500-oaktrail_lvds_i2c-c-v1-1-0a53a076ce20@google.com
> ---
>  drivers/gpu/drm/gma500/oaktrail_lvds_i2c.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/gma500/oaktrail_lvds_i2c.c b/drivers/gpu/drm/gma500/oaktrail_lvds_i2c.c
> index 06b5b2d70d48..939c53fd09e8 100644
> --- a/drivers/gpu/drm/gma500/oaktrail_lvds_i2c.c
> +++ b/drivers/gpu/drm/gma500/oaktrail_lvds_i2c.c
> @@ -141,7 +141,7 @@ struct gma_i2c_chan *oaktrail_lvds_i2c_init(struct drm_device *dev)
>  
>  	chan->drm_dev = dev;
>  	chan->reg = dev_priv->lpc_gpio_base;
> -	strncpy(chan->base.name, "gma500 LPC",  I2C_NAME_SIZE - 1);
> +	strscpy(chan->base.name, "gma500 LPC",  sizeof(chan->base.name));
>  	chan->base.owner = THIS_MODULE;
>  	chan->base.algo_data = &chan->algo;
>  	chan->base.dev.parent = dev->dev;
> 
> ---
> base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec
> change-id: 20230914-drivers-gpu-drm-gma500-oaktrail_lvds_i2c-c-a53c6d8bd62f
> 
> Best regards,
> --
> Justin Stitt <justinstitt@google.com>
>