linux-kernel - Re: [PATCH] selinux: fix memory leak on node

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Message-ID: <20160322202817.GA9459@mail.hallyn.com>
Date:	Tue, 22 Mar 2016 15:28:17 -0500
From:	"Serge E. Hallyn" <serge@...lyn.com>
To:	Colin King <colin.king@...onical.com>
Cc:	Paul Moore <paul@...l-moore.com>,
	Stephen Smalley <sds@...ho.nsa.gov>,
	Eric Paris <eparis@...isplace.org>,
	James Morris <james.l.morris@...cle.com>,
	"Serge E . Hallyn" <serge@...lyn.com>,
	Nick Kralevich <nnk@...gle.com>,
	Jeff Vander Stoep <jeffv@...gle.com>, selinux@...ho.nsa.gov,
	linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] selinux: fix memory leak on node_ptr on error return path

Quoting Colin King (colin.king@...onical.com):
> From: Colin Ian King <colin.king@...onical.com>
> 
> node_ptr is not being free'd if the list allocation fails, fix
> this by kfree'ing it before exiting on the error path.
> 
> Signed-off-by: Colin Ian King <colin.king@...onical.com>

Hi,

I'm not very familiar with this code any more, but are you sure
this is needed and doesn't cause a new bug?  It *looks* like
the avtab_insert_nonunique() actually inserts the node_ptr
into the policydb, and the policydb is the one that should
eventually free it.

> ---
>  security/selinux/ss/conditional.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
> index 456e1a9..5d010ef 100644
> --- a/security/selinux/ss/conditional.c
> +++ b/security/selinux/ss/conditional.c
> @@ -332,6 +332,7 @@ static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum
>  	list = kzalloc(sizeof(struct cond_av_list), GFP_KERNEL);
>  	if (!list) {
>  		rc = -ENOMEM;
> +		kfree(node_ptr);
>  		goto err;
>  	}
>  
> -- 
> 2.7.3