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,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 BEED1C2D0D1 for ; Mon, 16 Dec 2019 22:26:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F6E421835 for ; Mon, 16 Dec 2019 22:26:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=yahoo.com header.i=@yahoo.com header.b="M+Jr7eWb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728256AbfLPW0I (ORCPT ); Mon, 16 Dec 2019 17:26:08 -0500 Received: from sonic311-30.consmr.mail.ne1.yahoo.com ([66.163.188.211]:39827 "EHLO sonic311-30.consmr.mail.ne1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728255AbfLPW0H (ORCPT ); Mon, 16 Dec 2019 17:26:07 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1576535166; bh=Vw5PzqK2k4wespl9dNFvI58s/wyRhq2FOJ5+UO2Nnnc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From:Subject; b=M+Jr7eWbFnJCYxKN6NmCwDOfRbeCshIVCgnR/0gTw36EXb5RhbANJD5nMG5DIGqJqL6Xmz7VN4OmhkyrnvCoMnmXbqW/RGreYKfM0pacTl9EF2q0IsIOg+1sJG8QPzwb/HIc5R9xwYlDdX0nEWMjtwgVSQ6zOrWKN8AWsFmVEzVXHTCEejPT32F4nraO+iGA2J6UhOn5s2KCRjRP8xcMLg/S8q7tqOj/vsZvz3G3psOQhpHuSXGmd8fTOk0tyBJxQ+/nQFgtcjX3kYEy5j0RD8g9Gk+lsGagikU9RTu4hCXwP7EyUti6U47hI3wX5zjtwEn9nCpxSz1LHAoGEIApJg== X-YMail-OSG: ZwU3JmUVM1l0zja40jSiC44eO26Qvb6Wh_9PRyUfmgwENL5KCZEWRHr4EhXoh74 bNVPxPho5BOTzd_1.Ep8CTT5qEMrt3BiGWlFXMQcL8b3Qa1nCmFYTpur67FVBsYL7r85dRMVm5UC lGsFAizLV5_mbEz.K2QLVcs.UH8i_XjI.olK_cvNFDTD7LRTGvDNN90_D6ZXrxNXM0TmRNPK7rPc tcKNs7u3DbfR_Aer6GwXcJrTIjQwR5UInM4YIQRCFm4Du_1FJNCHLCTp8xxZdxnv43mOvitw_XIU VLl9t5us.o3B5EeN_qXJ5qqQZQCHQG2plJAbJn3pNGmI6G4WsUg5vHQzT7Yv_m90QMivEvFSjKGQ 8eC02OFq9VHQQpnLpbcTM9xvSRdzOU1ZsfTUapyFMfzUHTpPCa2JJ5m3KQa_DagWo0KIx1NQw8XV 4vpNAMm0eO2ChXzrs48SkzueXWGVp2h57_lG49LTigOXdDPaEVGLw84ErcSUDK.pSYZr.Yxtqyto I71agZZeJ_FDjG2X0gbS_pCmTggGiHtwlodCO3r70ToLgIHt10HQAg1r6NxCbwFcUUYEiqgvU1tJ TcA0aT1G4VwBDLFI_V1ve6l6zUW6WozQajA4_C6VaLkDpCQYMKzWAlyjlzbv7g7VZe3NNJyL65Jq G5pmNt2qe0.jpw2MazUOsZF6i9epRMS.BPgQaUxvzdhZQrJYzUdlUT0Bd9rPUywpRM8y9.fDEhEo pc9osJwyU6wEmj9bexE.1IHbZTlWUHqyfG0UWHjaa3l6VIPojLlqtLa3_tzLjIHfCRLHscQfHqup stRDEwhBNdtS8O_8mIGyDDReuHiOXa8p9ksbNLi3HD94OyhLBynojwftv.A8jvmG9mId0h70tebs kozBtEEuKoD.jtjiLvn0qOttPPRnSvrDoYD1kf2to2aEHHrpdzPxQwngQ3nbq0jxTE99n2CDgkVH Za13Q.aZpPQpJrV.BmhzGrz6WMgLjLBOpCjVCFUsmpe9B_K5SKObPMNGiVHrKWo.VZ8IvEuuuw9V 8mY0NKYG9e5wu_ia2c0Kk2mdAwozizh1eDtkY0Xb9k3j2VyWgY3PidFQ4qUe1kqNgGaSR3qupIQN _NWzi7nkTF_QHSXOEGQFxhag9c9TDUh_AyHJr7y_zLfGFCTebSO8EpbkxBQFRfOTo8P7N64RjFu0 ipGwyx8bp1ixmrvZVEQdXhz02bkZ83X_aQkxSCuKWYHPTEwqT6kiRA7WZ_e7CaqWTfYRhme8QjaB lehFrqE7JcunAz3_WtLdRxSkFTbkzcOaN5fOncxanzzxkCnx6G.scPJtJbp36l05ZQaqPX0A4vVv K7XnkNJvWkgPK_mHsi7yUpfdfrUVXPndCdFy0a5Qj91tjzQWQ5s5vjT7_JaUZN_8oGS09OCuVMIM 0ed50KHvt9v7bmpDkifrOVLpgseyPN_b7fGDYMIUNv04aP9SbadBpJ9pb93C6oIAwpw-- Received: from sonic.gate.mail.ne1.yahoo.com by sonic311.consmr.mail.ne1.yahoo.com with HTTP; Mon, 16 Dec 2019 22:26:06 +0000 Received: by smtp428.mail.bf1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 2b585332fad2a919f21222be56b5aee9; Mon, 16 Dec 2019 22:26:03 +0000 (UTC) From: Casey Schaufler To: casey.schaufler@intel.com, jmorris@namei.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Cc: keescook@chromium.org, john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com, sds@tycho.nsa.gov Subject: [PATCH v12 20/25] LSM: Verify LSM display sanity in binder Date: Mon, 16 Dec 2019 14:24:26 -0800 Message-Id: <20191216222431.4956-21-casey@schaufler-ca.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191216222431.4956-1-casey@schaufler-ca.com> References: <20191216222431.4956-1-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". 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 963641acf9dc..bca092dd4f00 100644 --- a/security/security.c +++ b/security/security.c @@ -738,9 +738,38 @@ 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); } -- 2.20.1