linux-kernel - Re: [PATCH] drm_edid-load: Fix a missing-check bug in drm_load_edid

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Message-ID: <87pno7n31o.fsf@intel.com>
Date:   Fri, 24 May 2019 21:02:59 +0300
From:   Jani Nikula <jani.nikula@...ux.intel.com>
To:     Gen Zhang <blackgod016574@...il.com>,
        maarten.lankhorst@...ux.intel.com, maxime.ripard@...tlin.com
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm_edid-load: Fix a missing-check bug in drm_load_edid_firmware()

On Fri, 24 May 2019, Gen Zhang <blackgod016574@...il.com> wrote:
> In drm_load_edid_firmware(), fwstr is allocated by kstrdup(). And fwstr
> is dereferenced in the following codes. However, memory allocation 
> functions such as kstrdup() may fail and returns NULL. Dereferencing 
> this null pointer may cause the kernel go wrong. Thus we should check 
> this kstrdup() operation.
> Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to
> the caller site.
>
> Signed-off-by: Gen Zhang <blackgod016574@...il.com>
> Reviewed-by: Jani Nikula <jani.nikula@...el.com>

Pushed to drm-misc-next, thanks for the patch.

BR,
Jani.

> ---
> diff --git a/drivers/gpu/drm/drm_edid_load.c b/drivers/gpu/drm/drm_edid_load.c
> index a491509..a0e107a 100644
> --- a/drivers/gpu/drm/drm_edid_load.c
> +++ b/drivers/gpu/drm/drm_edid_load.c
> @@ -290,6 +290,8 @@ struct edid *drm_load_edid_firmware(struct drm_connector *connector)
>  	 * the last one found one as a fallback.
>  	 */
>  	fwstr = kstrdup(edid_firmware, GFP_KERNEL);
> +	if (!fwstr)
> +		return ERR_PTR(-ENOMEM);
>  	edidstr = fwstr;
>  
>  	while ((edidname = strsep(&edidstr, ","))) {
> ---

-- 
Jani Nikula, Intel Open Source Graphics Center