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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 F152AC433FF for ; Wed, 31 Jul 2019 22:17:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C6329214DA for ; Wed, 31 Jul 2019 22:17:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="JtMG+7Gf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731361AbfGaWRV (ORCPT ); Wed, 31 Jul 2019 18:17:21 -0400 Received: from mail-qt1-f202.google.com ([209.85.160.202]:49644 "EHLO mail-qt1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731347AbfGaWRS (ORCPT ); Wed, 31 Jul 2019 18:17:18 -0400 Received: by mail-qt1-f202.google.com with SMTP id l16so56107764qtq.16 for ; Wed, 31 Jul 2019 15:17:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=0wvr7l0OfQCpncv5jcw0tGNb43fa+c615YU3AwXBobQ=; b=JtMG+7GfDdoaoq8E+Gpj5xUJvOyHAHIBQYN/5LMZv06DTj6ZvlEm2cJUCONAwzGUbP GK36LK9w+ftPnukYabwQIKWRmVwDi4Pl1KEKPEDvl7Fo3u/OJlTVhn3iV1fWGbjoy7QN s/HadNGszchMetFyBlbfiOchIuq8Tjvbgfm9Za5ZK20lXUFd79+hX5IE0h7NK+KIe4Xk jS4zcSBFQ3AEbVpTjuh/miN5rqBsVs1zzhXIKrsVVIkKzgVZZc6DQOgKMnowxWxNcRV4 gvGcQMZ9j9NkVGd9ArI82+xY/6cbbO0HFaHWXRZ+aEgjjS7Ix3QR6oGrnLeWOcVNfSTA uruw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=0wvr7l0OfQCpncv5jcw0tGNb43fa+c615YU3AwXBobQ=; b=DaQF+R1wRByghaIRqPcYHSOfv4cGHyv/dtpNxz0nQi4eefpr5vAsa/cwEEUKHPwHQS RmcX+BYy/CgUVMnrX8xjhn5npWRunT6FPo4lf+70EQ8bd8h+olnEivngwjLQDb07eFii UlozdEtRKlFdM8g+AohOhPqEGEpGNtpGbgtNYOt08kyViIJWCfy5UpRzVVFhxkJyAPVc xGcihNJqAA8JYiLvNSv4noaH5ON1xPeWufaO3xrtvrGLkKCEX34CIru0nrtXzsBfdG4S +XSGbY+TC6AP8zCjdJXQmb4r8bsNF0UHsA+LUXlnfUirWTHOUSw6/9ixBj/JNz89xbPL nb7A== X-Gm-Message-State: APjAAAWd/z0IcH9N7NkWZ0QLln2J0dozQ3/Wo8bTuZGo3jsYgzwIHaJJ uGhByozPcAUT2fB0LmsoV3daoegtibllgMmxujN5jw== X-Google-Smtp-Source: APXvYqxUoO/oavOOyoTYQRAm2XiiclbrazlFt1RtxZDfQMp3ob+EXXLfNSnGBHTCU7U7KZPBAfTvul8eCr2Xy8uirW8VdQ== X-Received: by 2002:a37:d95:: with SMTP id 143mr52836481qkn.132.1564611437244; Wed, 31 Jul 2019 15:17:17 -0700 (PDT) Date: Wed, 31 Jul 2019 15:16:08 -0700 In-Reply-To: <20190731221617.234725-1-matthewgarrett@google.com> Message-Id: <20190731221617.234725-21-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190731221617.234725-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.22.0.770.g0f2c4a37fd-goog Subject: [PATCH V37 20/29] x86/mmiotrace: Lock down the testmmiotrace module From: Matthew Garrett To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, David Howells , Thomas Gleixner , Matthew Garrett , Steven Rostedt , Kees Cook , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Howells The testmmiotrace module shouldn't be permitted when the kernel is locked down as it can be used to arbitrarily read and write MMIO space. This is a runtime check rather than buildtime in order to allow configurations where the same kernel may be run in both locked down or permissive modes depending on local policy. Suggested-by: Thomas Gleixner Signed-off-by: David Howells Acked-by: Steven Rostedt (VMware) Reviewed-by: Kees Cook cc: Thomas Gleixner cc: Steven Rostedt cc: Ingo Molnar cc: "H. Peter Anvin" cc: x86@kernel.org --- arch/x86/mm/testmmiotrace.c | 5 +++++ include/linux/security.h | 1 + security/lockdown/lockdown.c | 1 + 3 files changed, 7 insertions(+) diff --git a/arch/x86/mm/testmmiotrace.c b/arch/x86/mm/testmmiotrace.c index 0881e1ff1e58..a8bd952e136d 100644 --- a/arch/x86/mm/testmmiotrace.c +++ b/arch/x86/mm/testmmiotrace.c @@ -8,6 +8,7 @@ #include #include #include +#include static unsigned long mmio_address; module_param_hw(mmio_address, ulong, iomem, 0); @@ -115,6 +116,10 @@ static void do_test_bulk_ioremapping(void) static int __init init(void) { unsigned long size = (read_far) ? (8 << 20) : (16 << 10); + int ret = security_locked_down(LOCKDOWN_MMIOTRACE); + + if (ret) + return ret; if (mmio_address == 0) { pr_err("you have to use the module argument mmio_address.\n"); diff --git a/include/linux/security.h b/include/linux/security.h index 43fa3486522b..3f7b6a4cd65a 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -114,6 +114,7 @@ enum lockdown_reason { LOCKDOWN_PCMCIA_CIS, LOCKDOWN_TIOCSSERIAL, LOCKDOWN_MODULE_PARAMETERS, + LOCKDOWN_MMIOTRACE, LOCKDOWN_INTEGRITY_MAX, LOCKDOWN_CONFIDENTIALITY_MAX, }; diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c index 5177938cfa0d..37b7d7e50474 100644 --- a/security/lockdown/lockdown.c +++ b/security/lockdown/lockdown.c @@ -29,6 +29,7 @@ static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = { [LOCKDOWN_PCMCIA_CIS] = "direct PCMCIA CIS storage", [LOCKDOWN_TIOCSSERIAL] = "reconfiguration of serial port IO", [LOCKDOWN_MODULE_PARAMETERS] = "unsafe module parameters", + [LOCKDOWN_MMIOTRACE] = "unsafe mmio", [LOCKDOWN_INTEGRITY_MAX] = "integrity", [LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality", }; -- 2.22.0.770.g0f2c4a37fd-goog