From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932348AbdBIRPy (ORCPT ); Thu, 9 Feb 2017 12:15:54 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:55290 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752038AbdBIROi (ORCPT ); Thu, 9 Feb 2017 12:14:38 -0500 From: Colin King To: Casey Schaufler , James Morris , "Serge E . Hally" , linux-security-module@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH][V2] Smack: fix a dereference before null check on sock->sk Date: Thu, 9 Feb 2017 17:11:27 +0000 Message-Id: <20170209171127.5029-1-colin.king@canonical.com> X-Mailer: git-send-email 2.10.2 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King The initialisation of pointer ssp is from a dereference on sock->sk before sock-sk is null checked, hence there is a potential for a null pointer deference. Fix this by moving the assignment of ssp to just before it is used in the call to smk_ipv6_check. Also minor clean up of code to reduce #ifdef noise. Detected with CoverityScan, CID#1324196 ("Dereference before null check") Signed-off-by: Colin Ian King --- security/smack/smack_lsm.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index fc8fb31..0c5656d 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -2897,10 +2897,6 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap, #if IS_ENABLED(CONFIG_IPV6) struct sockaddr_in6 *sip = (struct sockaddr_in6 *)sap; #endif -#ifdef SMACK_IPV6_SECMARK_LABELING - struct smack_known *rsp; - struct socket_smack *ssp = sock->sk->sk_security; -#endif if (sock->sk == NULL) return 0; @@ -2915,10 +2911,17 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap, if (addrlen < sizeof(struct sockaddr_in6)) return -EINVAL; #ifdef SMACK_IPV6_SECMARK_LABELING - rsp = smack_ipv6host_label(sip); - if (rsp != NULL) - rc = smk_ipv6_check(ssp->smk_out, rsp, sip, - SMK_CONNECTING); + { + struct smack_known *rsp = smack_ipv6host_label(sip); + + if (rsp != NULL) { + struct socket_smack *ssp = + sock->sk->sk_security; + + rc = smk_ipv6_check(ssp->smk_out, rsp, sip, + SMK_CONNECTING); + } + } #endif #ifdef SMACK_IPV6_PORT_LABELING rc = smk_ipv6_port_check(sock->sk, sip, SMK_CONNECTING); -- 2.10.2