From patchwork Mon May 4 17:57:42 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 226426 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3ABB5C47257 for ; Mon, 4 May 2020 18:02:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D69E2073B for ; Mon, 4 May 2020 18:02:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588615324; bh=V7X8SJgcPJFFssox4XmJ0tvNWklV+ZOCfm7PUf8xJc0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=BUyMqnlZmGw3/b7YT3T76Y48jto9YmtJPDCy04W3eA+Xbqr1O2mVXs4v75VOjeiur s53bOaGzCv/nSlisg8UINSLGawJcON2b44g+hrAyDffNQNA/oL0Cby8VoqdGioOnun dl6KvTaFkqDl6538a8bckLyeB9a80DdmwG+JA3qQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731257AbgEDSCD (ORCPT ); Mon, 4 May 2020 14:02:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:58058 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731264AbgEDSCC (ORCPT ); Mon, 4 May 2020 14:02:02 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B14F22073B; Mon, 4 May 2020 18:02:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588615321; bh=V7X8SJgcPJFFssox4XmJ0tvNWklV+ZOCfm7PUf8xJc0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TsejKngxdhRef+QWGO0zlFPzXsrJaLObAWnLxTnUAaRN3uteldFMcY7R7lAI5EuIK +P/6gg5vpZsMTWH43m36DYe1aNG+XuTMJ7hdqMwpxesHTIpdvJJm/x1U/Xzei55dE2 QmofdU1m6tdSB5z0RTJZw2CbI8JaXHMZZnrAEY3I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dmitry Vyukov , Stephen Smalley , Paul Moore Subject: [PATCH 4.19 29/37] selinux: properly handle multiple messages in selinux_netlink_send() Date: Mon, 4 May 2020 19:57:42 +0200 Message-Id: <20200504165451.358601101@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200504165448.264746645@linuxfoundation.org> References: <20200504165448.264746645@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Paul Moore commit fb73974172ffaaf57a7c42f35424d9aece1a5af6 upstream. Fix the SELinux netlink_send hook to properly handle multiple netlink messages in a single sk_buff; each message is parsed and subject to SELinux access control. Prior to this patch, SELinux only inspected the first message in the sk_buff. Cc: stable@vger.kernel.org Reported-by: Dmitry Vyukov Reviewed-by: Stephen Smalley Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman --- security/selinux/hooks.c | 70 ++++++++++++++++++++++++++++++----------------- 1 file changed, 45 insertions(+), 25 deletions(-) --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -5595,40 +5595,60 @@ static int selinux_tun_dev_open(void *se static int selinux_nlmsg_perm(struct sock *sk, struct sk_buff *skb) { - int err = 0; - u32 perm; + int rc = 0; + unsigned int msg_len; + unsigned int data_len = skb->len; + unsigned char *data = skb->data; struct nlmsghdr *nlh; struct sk_security_struct *sksec = sk->sk_security; + u16 sclass = sksec->sclass; + u32 perm; - if (skb->len < NLMSG_HDRLEN) { - err = -EINVAL; - goto out; - } - nlh = nlmsg_hdr(skb); + while (data_len >= nlmsg_total_size(0)) { + nlh = (struct nlmsghdr *)data; - err = selinux_nlmsg_lookup(sksec->sclass, nlh->nlmsg_type, &perm); - if (err) { - if (err == -EINVAL) { + /* NOTE: the nlmsg_len field isn't reliably set by some netlink + * users which means we can't reject skb's with bogus + * length fields; our solution is to follow what + * netlink_rcv_skb() does and simply skip processing at + * messages with length fields that are clearly junk + */ + if (nlh->nlmsg_len < NLMSG_HDRLEN || nlh->nlmsg_len > data_len) + return 0; + + rc = selinux_nlmsg_lookup(sclass, nlh->nlmsg_type, &perm); + if (rc == 0) { + rc = sock_has_perm(sk, perm); + if (rc) + return rc; + } else if (rc == -EINVAL) { + /* -EINVAL is a missing msg/perm mapping */ pr_warn_ratelimited("SELinux: unrecognized netlink" - " message: protocol=%hu nlmsg_type=%hu sclass=%s" - " pig=%d comm=%s\n", - sk->sk_protocol, nlh->nlmsg_type, - secclass_map[sksec->sclass - 1].name, - task_pid_nr(current), current->comm); - if (!enforcing_enabled(&selinux_state) || - security_get_allow_unknown(&selinux_state)) - err = 0; + " message: protocol=%hu nlmsg_type=%hu sclass=%s" + " pid=%d comm=%s\n", + sk->sk_protocol, nlh->nlmsg_type, + secclass_map[sclass - 1].name, + task_pid_nr(current), current->comm); + if (enforcing_enabled(&selinux_state) && + !security_get_allow_unknown(&selinux_state)) + return rc; + rc = 0; + } else if (rc == -ENOENT) { + /* -ENOENT is a missing socket/class mapping, ignore */ + rc = 0; + } else { + return rc; } - /* Ignore */ - if (err == -ENOENT) - err = 0; - goto out; + /* move to the next message after applying netlink padding */ + msg_len = NLMSG_ALIGN(nlh->nlmsg_len); + if (msg_len >= data_len) + return 0; + data_len -= msg_len; + data += msg_len; } - err = sock_has_perm(sk, perm); -out: - return err; + return rc; } #ifdef CONFIG_NETFILTER