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Message-ID: <a1defc48-6b7c-8a4c-fff1-3baebab9a4f4@linux.intel.com>
Date:   Wed, 26 Jan 2022 10:08:36 +0000
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Subject: Re: [PATCH][next] drm/i915/guc: Use struct_size() helper in kmalloc()
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To:     "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>
Cc:     intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
References: <20220125180726.GA68646@embeddedor>
From:   Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Organization: Intel Corporation UK Plc
In-Reply-To: <20220125180726.GA68646@embeddedor>
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On 25/01/2022 18:07, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version,
> in order to avoid any potential type mistakes or integer overflows that,
> in the worst scenario, could lead to heap overflows.
> 
> Also, address the following sparse warnings:
> drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c:792:23: warning: using sizeof on a flexible structure
> 
> Link: https://github.com/KSPP/linux/issues/174
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>   drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> index aa6dd6415202..e352a1aad228 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> @@ -789,7 +789,7 @@ static struct ct_incoming_msg *ct_alloc_msg(u32 num_dwords)
>   {
>   	struct ct_incoming_msg *msg;
>   
> -	msg = kmalloc(sizeof(*msg) + sizeof(u32) * num_dwords, GFP_ATOMIC);
> +	msg = kmalloc(struct_size(msg, msg, num_dwords), GFP_ATOMIC);
>   	if (msg)
>   		msg->size = num_dwords;
>   	return msg;
> 

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Thanks for the patch, will merge shortly.

Regards,

Tvrtko