From patchwork Thu Jul 18 19:44:06 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Garrett X-Patchwork-Id: 11049497 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E9C231800 for ; Thu, 18 Jul 2019 19:46:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D791928179 for ; Thu, 18 Jul 2019 19:46:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CB01528521; Thu, 18 Jul 2019 19:46:05 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,RCVD_IN_DNSWL_HI,USER_IN_DEF_DKIM_WL autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4E8352883B for ; Thu, 18 Jul 2019 19:46:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403984AbfGRTpL (ORCPT ); Thu, 18 Jul 2019 15:45:11 -0400 Received: from mail-pg1-f201.google.com ([209.85.215.201]:53883 "EHLO mail-pg1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403928AbfGRTpL (ORCPT ); Thu, 18 Jul 2019 15:45:11 -0400 Received: by mail-pg1-f201.google.com with SMTP id t18so7275786pgu.20 for ; Thu, 18 Jul 2019 12:45:10 -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=JVVIIgLtDOBKlqbr3dAhxhQOQv6A3XP76vT4880U/G8=; b=SeXjRzGuTikZ6KQwoTivnohUXmbA9jZtlGvnhbW5Gf6eGO+4VFd29B9NCWSdujqhu/ 8fh2j1Om1PhG29VKxAvPHvHEnsKA9M4CYYYG/Lu9Hp+oZek3BD7S8Mig7S68+6KmwG1c /xo6cEaF8hx9fJlpJ/R/SstDqmbSIAXSy9NQlEtsI+j+VydsrXaPd4V0Beh16tfWRfGg F7FfxfLwPdOpWRZpLyOlY+tC4JNNX68ecbgofIWwHOVea/cuOB6mklZYjtyQQINP37o7 1nsCU4lqB4gv/44OPNg1qrVANEr2JgFG1OziWfA8hG4f0UGUfVWeP4bgBBn0aAiyTeRO foKA== 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=JVVIIgLtDOBKlqbr3dAhxhQOQv6A3XP76vT4880U/G8=; b=rR728YMtal0O0WIBTctL6wCfSJH1QP26FPcz3jx4es8zpEoMNsAzQ79CSY3Eg8XCCl Y2+uHMTvoJl+VK9r5Yqp2V91NPyogpT3XDy1Dl6wEnZQBJRQe5pT1dwkL82A2ACoxHFK xHqy8S7F7Aq+J6NMrRiz+8vkXtWe5rRPda9A/ykB87On5Tkzox40cVVdn8yDGstemcW/ gUf1QC4WPUXnoAcbMzsif/dpbpaix16gAz1BSmdnYHExzBvYxZREeuxrtmwN+MN+8H+h tF1k2LvKuJa3H5l3j/+aw4zu1jt4x/zC5ECvmNzjMPby2JBMGPM/OCiILNifjUHKWVsb vPtg== X-Gm-Message-State: APjAAAUiN1HMMBrguhE/6H8BfFxiSLWeR7z87+hx74bQpU+o5lMNSnVI Fj99yWwtqTx6lEbhHkkSqCuPvSKipBl1uQWw3f7gCw== X-Google-Smtp-Source: APXvYqyrMfaHa+wsv0nlaqRsdZ00CNxJSF2ky+cOy/8f3LYHWhlJwVQ8Qy4eVKCExKgmZMrlPSjOjbjg7/Xdu0/lTFJ7Wg== X-Received: by 2002:a63:20a:: with SMTP id 10mr49075232pgc.226.1563479110182; Thu, 18 Jul 2019 12:45:10 -0700 (PDT) Date: Thu, 18 Jul 2019 12:44:06 -0700 In-Reply-To: <20190718194415.108476-1-matthewgarrett@google.com> Message-Id: <20190718194415.108476-21-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190718194415.108476-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.22.0.510.g264f2c817a-goog Subject: [PATCH V36 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 , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP 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) cc: Thomas Gleixner cc: Steven Rostedt cc: Ingo Molnar cc: "H. Peter Anvin" cc: x86@kernel.org Reviewed-by: Kees Cook --- 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", };