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

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Message-ID: <56F1BB47.9070101@canonical.com>
Date:	Tue, 22 Mar 2016 21:38:15 +0000
From:	Colin Ian King <colin.king@...onical.com>
To:	Paul Moore <paul@...l-moore.com>,
	"Serge E. Hallyn" <serge@...lyn.com>
Cc:	Stephen Smalley <sds@...ho.nsa.gov>,
	Eric Paris <eparis@...isplace.org>,
	James Morris <james.l.morris@...cle.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

On 22/03/16 21:35, Paul Moore wrote:
> On Tue, Mar 22, 2016 at 4:28 PM, Serge E. Hallyn <serge@...lyn.com> wrote:
>> 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.
> 
> Exactly.  cond_insertf() calls avtab_insert_nonunique() which calls
> avtab_insert_node() which adds the node to the avtab.  The avtab will
> get cleaned up later by the error handling code in the cond_insertf()
> call chain.
> 
My bad, apologies.