From patchwork Tue Jul 23 10:00:15 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jia-Ju Bai X-Patchwork-Id: 11054225 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E6D4D1398 for ; Tue, 23 Jul 2019 10:00:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D74552842E for ; Tue, 23 Jul 2019 10:00:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CB6C5284F1; Tue, 23 Jul 2019 10:00:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D06B62842E for ; Tue, 23 Jul 2019 10:00:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726686AbfGWKA1 (ORCPT ); Tue, 23 Jul 2019 06:00:27 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:40102 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727467AbfGWKA1 (ORCPT ); Tue, 23 Jul 2019 06:00:27 -0400 Received: by mail-pg1-f194.google.com with SMTP id w10so19179947pgj.7; Tue, 23 Jul 2019 03:00:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=5OAJErAik0xYRiczuYg/dRLWg9Npudu/HIsd564SyVk=; b=dhRz0o072/BEcOUJhWA52ddEU/HGgqq6LhasWoT8YOHZvsSAKW337oGxSi0e93Owmv 6gfiwJMkzuSfycOhKDP4LWw9AhI8zzemt+PzF79gQzp56Sg/Tgm7ISHSaeGb4WskrkUi xaTvVKQRFv7b+kYCFZvV/kPT+Wy7tSPKys6ePiwR9iLwLt1hpZbT3IRLqkIiBCW+OmX4 sXqqE9VSlc9lgZw4se9BbU0eJT3ptv6hDXYK7eSRFjogawuIMDoYud8ZcBWHSFmIhjsq G0WpoR6K0MDB6d22cK3/kN0vix1CS7MmYZcKmd289zUZa601dz29++rdaoheisl04ilp f04A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=5OAJErAik0xYRiczuYg/dRLWg9Npudu/HIsd564SyVk=; b=oSDmCr33i52B/Ydy3j/17BwEiimMvJgl6H/73MtmNsdE8x9efm8LI2IJJWTb91uhbl iT3FdVXhBfK0c4DYhxoXlFz+EtwwoMU0rJKpb31njqAJaKJeTpbaHjW9uSBVtKael+32 3rspw5wuXF6Ae0RsPvYSNsybhuXaigThfe7nSQ0oEP9+R6UM8kKBq7f6um2vU6R827IT Fx/+dgvotnPvlECWzc3CacnA/vGMoBeRcTZbDvbEJeM6a1w9Du8/qcOhLfpJZsOXJXCj doBnUxYfp+GJcs1XJhgBAYVqOKU3b8h63CKkvh/WvWzQkQhrbdU7GWxDVnm3VeaCwHMO QhXg== X-Gm-Message-State: APjAAAXLxXIYf/ldvDtO5WsoAhuZdpOnutO9qccU09e3yK2u7hPKODbj KOEAZw0+cU2K0HnpSd0p0UE= X-Google-Smtp-Source: APXvYqwNWVAJYmjCW8kEPfETxNjyljUixVn9J0Y+PXozl+eLiUNPjvrPnnaCEuVfF1e4zAq/uJX/Mw== X-Received: by 2002:a17:90a:ca11:: with SMTP id x17mr82284773pjt.107.1563876026282; Tue, 23 Jul 2019 03:00:26 -0700 (PDT) Received: from oslab.tsinghua.edu.cn ([2402:f000:4:72:808::3ca]) by smtp.gmail.com with ESMTPSA id y12sm50328188pfn.187.2019.07.23.03.00.24 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 23 Jul 2019 03:00:25 -0700 (PDT) From: Jia-Ju Bai To: casey@schaufler-ca.com, jmorris@namei.org, serge@hallyn.com Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Jia-Ju Bai Subject: [PATCH] security: smack: Fix possible null-pointer dereferences in smack_socket_sock_rcv_skb() Date: Tue, 23 Jul 2019 18:00:15 +0800 Message-Id: <20190723100015.5400-1-baijiaju1990@gmail.com> X-Mailer: git-send-email 2.17.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP In smack_socket_sock_rcv_skb(), there is an if statement on line 3920 to check whether skb is NULL: if (skb && skb->secmark != 0) This check indicates skb can be NULL in some cases. But on lines 3931 and 3932, skb is used: ad.a.u.net->netif = skb->skb_iif; ipv6_skb_to_auditdata(skb, &ad.a, NULL); Thus, possible null-pointer dereferences may occur when skb is NULL. To fix these possible bugs, an if statement is added to check skb. These bugs are found by a static analysis tool STCheck written by us. Signed-off-by: Jia-Ju Bai --- security/smack/smack_lsm.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 4c5e5a438f8b..5c9fc8ba6e57 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -3925,6 +3925,8 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) skp = smack_ipv6host_label(&sadd); if (skp == NULL) skp = smack_net_ambient; + if (skb == NULL) + break; #ifdef CONFIG_AUDIT smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net); ad.a.u.net->family = family;