From mboxrd@z Thu Jan  1 00:00:00 1970
From: Casey Schaufler <casey@schaufler-ca.com>
Subject: Re: [RFC][PATCH 5/7] smack: import the security label in smack_secctx_to_secid()
Date: Wed, 27 Apr 2011 16:47:06 -0700
Message-ID: <4DB8AAFA.2050903@schaufler-ca.com>
References: <1303907657-18366-1-git-send-email-roberto.sassu@polito.it> <1303907657-18366-6-git-send-email-roberto.sassu@polito.it>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Cc: linux-security-module@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	dhowells@redhat.com, jmorris@namei.org, zohar@linux.vnet.ibm.com,
	safford@watson.ibm.com, tyhicks@linux.vnet.ibm.com,
	kirkland@canonical.com, ecryptfs-devel@lists.launchpad.net,
	eparis@redhat.com, sds@tycho.nsa.gov, selinux@tycho.nsa.gov,
	viro@zeniv.linux.org.uk, Casey Schaufler <casey@schaufler-ca.com>
To: Roberto Sassu <roberto.sassu@polito.it>
Return-path: <linux-security-module-owner@vger.kernel.org>
In-Reply-To: <1303907657-18366-6-git-send-email-roberto.sassu@polito.it>
Sender: linux-security-module-owner@vger.kernel.org
List-Id: linux-fsdevel.vger.kernel.org

On 4/27/2011 5:34 AM, Roberto Sassu wrote:
> The security label passed as argument in smack_secctx_to_secid() must be
> first imported in the 'smack_known_list' list before finding the security
> identifier associated to it. This allows the function
> set_security_override_from_ctx() to be performed successfully even if the
> label is not yet present in the smack list.
>
> Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>

Nacked-by: Casey Schaufler <casey@schaufler-ca.com>

security_secctx_to_secid() is called from the netlabel code
and hence cannot (to my understanding) allocate memory,
which is something that smk_import will do if the label is
new. I am willing to be convinced that doing so is safe,
but my understanding is that it is not.

> ---
>  security/smack/smack_lsm.c |    8 +++++++-
>  1 files changed, 7 insertions(+), 1 deletions(-)
>
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index 0e7ed31..6612ba1 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -3346,7 +3346,13 @@ static int smack_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
>   */
>  static int smack_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
>  {
> -	*secid = smack_to_secid(secdata);
> +	char *smack;
> +
> +	smack = smk_import(secdata, seclen);
> +	if (smack == NULL)
> +		return -EINVAL;
> +
> +	*secid = smack_to_secid(smack);
>  	return 0;
>  }
>