linux-kernel - Re: [PATCH linux-next v2 1/3] platform/x86/intel/tpmi: Fix double free in tpmi_create

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Date:   Thu, 16 Mar 2023 15:25:15 +0100
From:   Hans de Goede <hdegoede@...hat.com>
To:     Dongliang Mu <dzm91@...t.edu.cn>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Mark Gross <markgross@...nel.org>
Cc:     platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH linux-next v2 1/3] platform/x86/intel/tpmi: Fix double
 free in tpmi_create_device()

Hi,

On 3/9/23 05:01, Dongliang Mu wrote:
> The previous commit 6a192c0cbf38 ("platform/x86/intel/tpmi: Fix
> double free reported by Smatch") incorrectly handle the deallocation of
> res variable. As shown in the comment, intel_vsec_add_aux handles all
> the deallocation of res and feature_vsec_dev. Therefore, kfree(res) can
> still cause double free if intel_vsec_add_aux returns error.
> 
> Fix this by adjusting the error handling part in tpmi_create_device,
> following the function intel_vsec_add_dev.
> 
> Fixes: 6a192c0cbf38 ("platform/x86/intel/tpmi: Fix double free reported by Smatch")
> Signed-off-by: Dongliang Mu <dzm91@...t.edu.cn>

IIRC then after this v2 was posted I still saw some comments on the original v1 which was not posted on the list. Without the v1 comments being on the list and this archived, I have lost track of what the status of these patches is.

Srinivas, can you let me know if I should merge these, or if more changes are necessary ?

>From the off-list discussion of v1 I got the impression more changes are necessary, but I'm not sure.

Regards,

Hans




> ---
>  drivers/platform/x86/intel/tpmi.c | 17 ++++-------------
>  1 file changed, 4 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel/tpmi.c b/drivers/platform/x86/intel/tpmi.c
> index c999732b0f1e..882fe5e4763f 100644
> --- a/drivers/platform/x86/intel/tpmi.c
> +++ b/drivers/platform/x86/intel/tpmi.c
> @@ -215,8 +215,8 @@ static int tpmi_create_device(struct intel_tpmi_info *tpmi_info,
>  
>  	feature_vsec_dev = kzalloc(sizeof(*feature_vsec_dev), GFP_KERNEL);
>  	if (!feature_vsec_dev) {
> -		ret = -ENOMEM;
> -		goto free_res;
> +		kfree(res);
> +		return -ENOMEM;
>  	}
>  
>  	snprintf(feature_id_name, sizeof(feature_id_name), "tpmi-%s", name);
> @@ -242,17 +242,8 @@ static int tpmi_create_device(struct intel_tpmi_info *tpmi_info,
>  	 * feature_vsec_dev memory is also freed as part of device
>  	 * delete.
>  	 */
> -	ret = intel_vsec_add_aux(vsec_dev->pcidev, &vsec_dev->auxdev.dev,
> -				 feature_vsec_dev, feature_id_name);
> -	if (ret)
> -		goto free_res;
> -
> -	return 0;
> -
> -free_res:
> -	kfree(res);
> -
> -	return ret;
> +	return intel_vsec_add_aux(vsec_dev->pcidev, &vsec_dev->auxdev.dev,
> +				  feature_vsec_dev, feature_id_name);
>  }
>  
>  static int tpmi_create_devices(struct intel_tpmi_info *tpmi_info)