From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 547A2C2BA80 for ; Tue, 7 Apr 2020 00:23:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A4432072A for ; Tue, 7 Apr 2020 00:23:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=yahoo.com header.i=@yahoo.com header.b="C78uLjPj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726254AbgDGAW7 (ORCPT ); Mon, 6 Apr 2020 20:22:59 -0400 Received: from sonic313-15.consmr.mail.ne1.yahoo.com ([66.163.185.38]:41957 "EHLO sonic313-15.consmr.mail.ne1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726443AbgDGAW7 (ORCPT ); Mon, 6 Apr 2020 20:22:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1586218978; bh=/fnffqTEA/0DaZe47mjPbyqSQbsHYyxZdjwhQkMneco=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From:Subject; b=C78uLjPjq2sCAFWbOJFdkxPNVMXTKQB3759Qz25nrfg8I+NyUPGXBGox2yV7qCN2915XgowEWIe8R2hNkV0q7oghhqkr/eAEKF3Fhp3oT30ihEk4AOgMDvUnPcJvtHs/5y3MCb2SMRFUS3rzDLI7VzDymxDnePbTu3IcQn8HBshBnwRtH2ko8Psw0PWUT0+lmAUiSsUwejsiUW56lZrzsoXaWuKFXxorWxbx+t6vJvX/+wreWUX+Xtzr9NwupRtjmf3yR0OgVQSkCvxohgmxhVDRi4+rnHXDP9C0nTAfbIJscEjxLFNTsbUYP9fxUPXW8IJsNXTkXHXV9HAj9Tz4QA== X-YMail-OSG: GCpqnqQVM1mIprFvyLYc7yHx_1u1ig7fy5uAmDSJY630AjJPe1.Z5EbVVWyaPif SH_dET8_vWTDiyDQmXndlFTsHu64xflK08n3uKkyFBLu3Y3GzUS9V.OQOpu5mODBrGjobHMDE68k KiGs.PcVMJGphg8gih_CJLlho81BS6.f3iVLSWwpZCkbj6TKmwioh54G6TFnXuB.5eKUULzCly2q gzhkYsRGYkGHCZ8l1yK1dxeQ9TIuh12afQDVtdiMCOxZBiWMDp2vlzYS.0ACOwm39e1wmtNluvAj PYAAX.I83D9mKSjtTxz8Is_062w3lx38ohoeqvbxfmzEzCdSe1w53ERFL2Oe.JVhOnFhgHBI7lWx jpMJccI1yXtFFZ.MCBX.IpB1OqWz.W5wjzPDaGhToS_d1k3DN9Fiz2ngWGDFc1TAYFpLA3rxbb6h OrqSquTdpjUogkXx1VXbk4ooQYWUaCTJznNRziKeoF7VndU1KvNbB0oovAOYeyvhrd4SGV23YnLf Ac6SqeO3rB_91EvBU4LY9r0cdmnb2J0DSmQf1b1MbPGgVkW.n2lFv78hmxwyiDtmOhnglZeq4bvx AFrJx5aeqMjbA64agAapKrQYpY8cu.Cnyn0U9JyCCizqnudyXbPXmzXoPTrJQAMXT_1IsppuKu_X HDmufzQ5vOoE0_rrlTi1s5XM7W7XJz1MghjQHVZtDP6IV1GjdDT1GLEsZxJGcCUAHdlGS1czSzfy SLdiI5s4Q.6xAWZeGDQhitvQkdvNk8D4x1SzRB0M_gFetfW3UlgQYqDXkB9_T31CtktZGT7Pq.c6 BKZhyRg5Af8KuLr0.Yg3spZzpDkTK7ZvZg2ESfK_ktQQYl2ACj8V8gtgRzgxFhkCYygT7WrlG1fJ kJGmbWy.ENV46hJ1uWRu.l7bp.Pn4vUuqUrDDtmV0s5bcnryww_AtpRKcXVzT9JNe5nmnSbmWgXV Byn0hSJcaU99Ua1xzmEj4E.gDxnT6ujtK0.QQ0XkfTYl6Z2sH7JiifbL9fnDGbMm6Ps3Ea6CBd2Q E6ezmQXXw0WfW4Wzyj6zu3CwlKZQkBTP3GlrQb2t2P1Km_m9O6mjjbkjIYErbVp40ADaapyyfngK PBX50KwEVwQ3zpHmm2JXyKcy7u_ybvCUv6X4xErcE1w70QmVACzg8_QW2eCRnKOClVjUS1nC5lrq aiDmPC21oAUdK3BerVUTArZo87arpBkKU3u4VBVtNCeZjEMh7v.5U2_ruVdLZmdnaGzUxyF4rqdZ ZyGQ_2Y1EOMo5op68t3a_H.SmMhvu4EaFNlfQFxVnO1TJ70zGUbb6ZKPdPImFgSyWzty4FnpqhEj dYX_q44k5lu19Y2w2FGpyUSLIryvHo4DKIi2YoxX3350TRSvn7_pymLwErlbWodre4h4wXhhhHcv RffNCx3.CMOxjFLuJYCXkQjR042fMFy9.y9Vo0KZUsVwsOEDUcQ-- Received: from sonic.gate.mail.ne1.yahoo.com by sonic313.consmr.mail.ne1.yahoo.com with HTTP; Tue, 7 Apr 2020 00:22:58 +0000 Received: by smtp432.mail.bf1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 1b2fba97d77f9ea95418fb25b4adff9b; Tue, 07 Apr 2020 00:22:53 +0000 (UTC) From: Casey Schaufler To: casey.schaufler@intel.com, jmorris@namei.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Cc: casey@schaufler-ca.com, keescook@chromium.org, john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com, sds@tycho.nsa.gov, linux-audit@redhat.com Subject: [PATCH v16 19/23] LSM: Verify LSM display sanity in binder Date: Mon, 6 Apr 2020 17:01:55 -0700 Message-Id: <20200407000159.43602-20-casey@schaufler-ca.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200407000159.43602-1-casey@schaufler-ca.com> References: <20200407000159.43602-1-casey@schaufler-ca.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Verify that the tasks on the ends of a binder transaction use the same "display" security module. This prevents confusion of security "contexts". Acked-by: Stephen Smalley Signed-off-by: Casey Schaufler --- security/security.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/security/security.c b/security/security.c index 84f33bd4990a..b7c2ed1eee42 100644 --- a/security/security.c +++ b/security/security.c @@ -769,9 +769,38 @@ int security_binder_set_context_mgr(struct task_struct *mgr) return call_int_hook(binder_set_context_mgr, 0, mgr); } +/** + * security_binder_transaction - Binder driver transaction check + * @from: source of the transaction + * @to: destination of the transaction + * + * Verify that the tasks have the same LSM "display", then + * call the security module hooks. + * + * Returns -EINVAL if the displays don't match, or the + * result of the security module checks. + */ int security_binder_transaction(struct task_struct *from, struct task_struct *to) { + int from_display = lsm_task_display(from); + int to_display = lsm_task_display(to); + + /* + * If the display is LSMBLOB_INVALID the first module that has + * an entry is used. This will be in the 0 slot. + * + * This is currently only required if the server has requested + * peer contexts, but it would be unwieldly to have too much of + * the binder driver detail here. + */ + if (from_display == LSMBLOB_INVALID) + from_display = 0; + if (to_display == LSMBLOB_INVALID) + to_display = 0; + if (from_display != to_display) + return -EINVAL; + return call_int_hook(binder_transaction, 0, from, to); } -- 2.24.1