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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 86100C433DF for ; Wed, 26 Aug 2020 15:22:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DEF022B43 for ; Wed, 26 Aug 2020 15:22:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=yahoo.com header.i=@yahoo.com header.b="dT9+X8g3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727061AbgHZPWa (ORCPT ); Wed, 26 Aug 2020 11:22:30 -0400 Received: from sonic310-30.consmr.mail.ne1.yahoo.com ([66.163.186.211]:33359 "EHLO sonic310-30.consmr.mail.ne1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728012AbgHZPW3 (ORCPT ); Wed, 26 Aug 2020 11:22:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1598455347; bh=x30nPZLpFPTTON9xwug49FDlGI4IQDIqcRfVllA7iMU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From:Subject; b=dT9+X8g35TiPkzYybXrzx8DP0GGrqs3MjXhBikeP5hZMV2c14cshTDXa7EtH/Clh/8T4JRI5qoCFHBZ4jSO/MiHJyh4peYkyNxOBWYNy/pJu/6rsftWJbPL1j+uLJ5VjpZa0ew0P7Hn54PYS2QBPUpQW+P5DvSkUFGQGAIf0kitPpSielz1GFYLazOzt+L6MhmkIDeQWiJoaB98IihE8oirxtbzCuauJDG2EsyZCMC26rbGBBnKc5Jzervy7Epddd9oHg3wzPSB67+dOjGvvniOtgtc/TU7tYUtBGaVD4PWhgS9nwh0E+0JZafG1ntAPMFKkAEYszlVY8MjuqdzO6Q== X-YMail-OSG: 5IcbxjgVM1lmlk3ezubrvSl7kP_1wa_t8ow8aFSryOPnjYfQ9j_YaHtZ3pHdV1T IUZ_NhWr4j2qbDiFZ0kiIAgwuN_I9X0hO9tm3I256DABDOf9YowFGSzoSR9U0t21.TLGA4qka3O. x0Spr9PjCcZW22DYnOCxkfue0m79GR2f6JI8e_uXk.Sn0lMV5ddsLmyOBAJAqtpX5zcLd.i2wQaJ zOA.xd93e4kQbBxMk_vckfIhJ6TYWzViYc07NyZxNIzjg6p5UO5kYjUGr01fgiJcIFSddeNekCY1 9rlqF_oL0JnANiHjHAul2AJqK_4BeKmjripIBlu0Ii9C9K0CVKmSI7f530M6TdWktD2qNbuN2lWG V3hx6XKNpaK6vBxShBPFNb7QUhtBUSPLdHVyPQphV.AB7IyRKtOwctoUY1JhOlhtighJi_eiV7OL hkleqXBHdod1o7rcDzHN7iva2LiGHOUUcOACpYMybZ4GJnp_6LDOULZhw1b7mOaA8GpXAhsmG9Yw BTqdwkItLjukXYfnDqWqCDF7sa.3ewmctYfjYUwERL4QbeTNBp0nwQDWXlre8gLBaBPwGlKGeyGR qzjTgVjOwAcnVqfiZrHZZl8SXR9Z6W0SyCzqTlTk9IYYn3qugjX5SZjXF6UBAdSlgiyLh0QTWyfZ Thh15fOAriN00XXtDaIOw81bOoc2JgqHu_7hRaXHNb3Wcrs7cTJ_lr7K35dZXxiMG6juCsR_iCuM JWMLBRXffr8dx_8eKtKD0g3P1hjQt39e553WVCQhZG5m9st6zQ5cPP6fE8KpByon1KkgM28Ri7Cr LAPy3E1o6YZ.g1HfOQJKDo7vqlTGVjGAL3mkOcH.zQCfcJfCrQ9aBvFrmfven7sljETONlJxMwsB P_j8xJBh6qPlmUOjNIdMYeFg46c3rxMKNJxANQWTLySwgi75Ib7IniBFiX4KrRo0.afEybrizB6T RBbIajuxgJ.NcIS6zsnM8faTlP2u9ZTg1XY_qngSq5PQI5ofGzyqm5eT1fgxdMDt55tu33yQguef 0Tm9BZhirK1njK_WsiDrOi3MDV0HsgnqKyQKqUUTFK3iGXf3CDE3.qAFquRH4.E_GfWOozh1vufK c1PUDJ3vG9ib3.qQBNgyO8D8JEBMygYg7cjyN8Ct1aosxF9I655FDu8UxOlpDRmHSQo_T5nn27Ut TvtCaxt.2mSFYzH4.xEmBNSuHzIac.aI4tjAtxKJUhEX2TSlX0SvdzLCXyGaZ_YOpF_3h7Uny6B4 HrMbTy27yj.mc4wGZnvauK8EwZy7xkiT.cTdDL7VQDYhDOzR2bZq2cu_QHf2EX4SNHlZTj94ao_b NvJTJCZj.HjwUEtxUyqMRyzdVle92rjULjFgoCArPB8EeipdnQCxd31_l6cBvtiItxkmwsDyEqyA tqNy2w2E9Lf2YDjrwXMQW_HNsnuIc9xxvtBDo5hIHa8uLM5n3FDUHRz3esxvVLQMq03PrNZfoBtu P8Uq4ObRyxnObxs1anXdNlethvIxnTLmZglz3QVVofVLvYFaCHhu20skw52hsRhurdQzoBxy9qHk yGopcd03296xt4yw4tG_4tZzE4xX_853EsO2HEeIQZ.k- Received: from sonic.gate.mail.ne1.yahoo.com by sonic310.consmr.mail.ne1.yahoo.com with HTTP; Wed, 26 Aug 2020 15:22:27 +0000 Received: by smtp422.mail.gq1.yahoo.com (VZM Hermes SMTP Server) with ESMTPA ID 4e2715e5e80abc834d7fac6d2c42f5da; Wed, 26 Aug 2020 15:22:24 +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, linux-audit@redhat.com, keescook@chromium.org, john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com, sds@tycho.nsa.gov Subject: [PATCH v20 19/23] LSM: Verify LSM display sanity in binder Date: Wed, 26 Aug 2020 07:52:43 -0700 Message-Id: <20200826145247.10029-20-casey@schaufler-ca.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200826145247.10029-1-casey@schaufler-ca.com> References: <20200826145247.10029-1-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". Reviewed-by: Kees Cook 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 ddbaf2073b02..95b48721fb17 100644 --- a/security/security.c +++ b/security/security.c @@ -788,9 +788,38 @@ 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