linux-kernel - Re: [PATCH 2/2] batman-adv: Improve exception handling in batadv_throw

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Date: Tue, 02 Jan 2024 12:24:05 +0100
From: Sven Eckelmann <sven@...fation.org>
To: b.a.t.m.a.n@...ts.open-mesh.org, netdev@...r.kernel.org,
 kernel-janitors@...r.kernel.org, Antonio Quartulli <a@...table.cc>,
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>, Marek Lindner <mareklindner@...mailbox.ch>,
 Paolo Abeni <pabeni@...hat.com>, Simon Wunderlich <sw@...onwunderlich.de>,
 Markus Elfring <Markus.Elfring@....de>
Cc: LKML <linux-kernel@...r.kernel.org>
Subject:
 Re: [PATCH 2/2] batman-adv: Improve exception handling in
 batadv_throw_uevent()

On Tuesday, 2 January 2024 08:12:56 CET Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Tue, 2 Jan 2024 07:52:21 +0100
> 
> The kfree() function was called in up to three cases by
> the batadv_throw_uevent() function during error handling
> even if the passed variable contained a null pointer.
> This issue was detected by using the Coccinelle software.
> 
> * Thus adjust jump targets.
> 
> * Reorder kfree() calls at the end.
> 
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>

Acked-by: Sven Eckelmann <sven@...fation.org>

> ---
>  net/batman-adv/main.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
> index 5fc754b0b3f7..75119f1ffccc 100644
> --- a/net/batman-adv/main.c
> +++ b/net/batman-adv/main.c
> @@ -691,29 +691,31 @@ int batadv_throw_uevent(struct batadv_priv *bat_priv, enum batadv_uev_type type,
>  				  "%s%s", BATADV_UEV_TYPE_VAR,
>  				  batadv_uev_type_str[type]);
>  	if (!uevent_env[0])
> -		goto out;
> +		goto report_error;
> 
>  	uevent_env[1] = kasprintf(GFP_ATOMIC,
>  				  "%s%s", BATADV_UEV_ACTION_VAR,
>  				  batadv_uev_action_str[action]);
>  	if (!uevent_env[1])
> -		goto out;
> +		goto free_first_env;
> 
>  	/* If the event is DEL, ignore the data field */
>  	if (action != BATADV_UEV_DEL) {
>  		uevent_env[2] = kasprintf(GFP_ATOMIC,
>  					  "%s%s", BATADV_UEV_DATA_VAR, data);
>  		if (!uevent_env[2])
> -			goto out;
> +			goto free_second_env;
>  	}
> 
>  	ret = kobject_uevent_env(bat_kobj, KOBJ_CHANGE, uevent_env);
> -out:
> -	kfree(uevent_env[0]);
> -	kfree(uevent_env[1]);
>  	kfree(uevent_env[2]);
> +free_second_env:
> +	kfree(uevent_env[1]);
> +free_first_env:
> +	kfree(uevent_env[0]);
> 
>  	if (ret)
> +report_error:
>  		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
>  			   "Impossible to send uevent for (%s,%s,%s) event (err: %d)\n",
>  			   batadv_uev_type_str[type],
> --
> 2.43.0
> 
> 


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