From patchwork Thu Aug 8 00:07:12 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Garrett X-Patchwork-Id: 11082955 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 487FB13B1 for ; Thu, 8 Aug 2019 00:09:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 38AB928AB7 for ; Thu, 8 Aug 2019 00:09:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2C3EF28AC8; Thu, 8 Aug 2019 00:09:09 +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 A75A728AB7 for ; Thu, 8 Aug 2019 00:09:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389086AbfHHAJI (ORCPT ); Wed, 7 Aug 2019 20:09:08 -0400 Received: from mail-vs1-f74.google.com ([209.85.217.74]:41871 "EHLO mail-vs1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389703AbfHHAIR (ORCPT ); Wed, 7 Aug 2019 20:08:17 -0400 Received: by mail-vs1-f74.google.com with SMTP id k1so23498780vsq.8 for ; Wed, 07 Aug 2019 17:08:16 -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=BDkDRuySmH99+uoxWfrhpwfmKNKn2qJaU9U/nzEU3gQ85Ycz5x21SymY69Kx+7BgVn TZPOXubIcxk1FUPhB6QPNSl3h3POtgH+QVLlxpPrMnvAgPD+plxy9dozCgZIlKD0ESsz iVLNLuxn0fk0sWBXSMA72U0mJt7FbH0qWwkKkcF87ZfT348ivWRfkl/gDkGlhug9gwlZ GeZmmEpvW3AYDgqzlpv5CvDBjmAv1VmBDOChd3NOcXBd+mKUdcddnrKvAKhtkENqp5T1 M4+uNNJlDgYygp6TjDT3uFuRNHqNmm0ky2+YxmrB0VARBMGlEhTuKkGXpnJE2AgWP9HT l8cw== 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=ndZ3LtoZ22x9iRyR3ZyxEDkJq/TTUiVboYA/f3CVaCpljygof77n78qE4jv/mxSu5U KY7vErHd2t2UpReuMqlvuvTX7DVnlaztaqNKW7vZLevjkeS8KC4mju9eKpGMrnisPgqh gpgW8kOkT5iI/47rx8gH/BurWVk5LyMBB2I/SVVMM5poHxZEl01i3F9NRaMCTJw4MIXo sJYHuS05Zh7nvwmz+yfIFUpPWcdY+YaeCyFAM/pCViRi2uWBrrCYiUuNpFBc6l68stD1 FJKariXcsKeMzoafi3FcuNV+CUqsNTmB976G+MsqzAUzbMUbO6lFTH+72UYZHO69tMSk AtJg== X-Gm-Message-State: APjAAAWPr/1GMG+e2hQk+3akHmFSL+4+vYOEgXWNidV2iE4SIHTsQoeU u2MBcxZpG6ggbn+DoakgoWkHivJL+hl5twJxXlOcOQ== X-Google-Smtp-Source: APXvYqxcfpqqsavzaQSk6TZq5rSUgP4b30JIhvbXsxs7veg7Eg3YU6weBFgQ8LHBcnt8hZcdSe5A5T0ZlXIZX06xlzylkg== X-Received: by 2002:ab0:6e2:: with SMTP id g89mr7736803uag.56.1565222896120; Wed, 07 Aug 2019 17:08:16 -0700 (PDT) Date: Wed, 7 Aug 2019 17:07:12 -0700 In-Reply-To: <20190808000721.124691-1-matthewgarrett@google.com> Message-Id: <20190808000721.124691-21-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190808000721.124691-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.22.0.770.g0f2c4a37fd-goog Subject: [PATCH V38 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 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) 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", };