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

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Message-ID: <CAHC9VhThVmP14F_Eu3C=bBWPGkufFO5v9J0UFyeLFPLNW1FA7Q@mail.gmail.com>
Date:	Tue, 22 Mar 2016 17:35:24 -0400
From:	Paul Moore <paul@...l-moore.com>
To:	Colin King <colin.king@...onical.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 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.

-- 
paul moore
www.paul-moore.com