linux-kernel - Re: [PATCH] af_key: Fix memory leak in key_notify

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Message-ID: <20190614085346.GN17989@gauss3.secunet.de>
Date:   Fri, 14 Jun 2019 10:53:46 +0200
From:   Steffen Klassert <steffen.klassert@...unet.com>
To:     Young Xiao <92siuyang@...il.com>
CC:     <herbert@...dor.apana.org.au>, <davem@...emloft.net>,
        <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] af_key: Fix memory leak in key_notify_policy.

On Fri, Jun 14, 2019 at 04:26:26PM +0800, Young Xiao wrote:
> We leak the allocated out_skb in case pfkey_xfrm_policy2msg() fails.
> Fix this by freeing it on error.
> 
> Signed-off-by: Young Xiao <92siuyang@...il.com>
> ---
>  net/key/af_key.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/key/af_key.c b/net/key/af_key.c
> index 4af1e1d..ec414f6 100644
> --- a/net/key/af_key.c
> +++ b/net/key/af_key.c
> @@ -2443,6 +2443,7 @@ static int key_pol_get_resp(struct sock *sk, struct xfrm_policy *xp, const struc
>  	}
>  	err = pfkey_xfrm_policy2msg(out_skb, xp, dir);
>  	if (err < 0)
> +		kfree_skb(out_skb);
>  		goto out;

Did you test this?

You need to add braces, otherwise 'goto out' will happen unconditionally.

>  
>  	out_hdr = (struct sadb_msg *) out_skb->data;
> @@ -2695,6 +2696,7 @@ static int dump_sp(struct xfrm_policy *xp, int dir, int count, void *ptr)
>  
>  	err = pfkey_xfrm_policy2msg(out_skb, xp, dir);
>  	if (err < 0)
> +		kfree_skb(out_skb);
>  		return err;

Same here.