From patchwork Sat Jun 22 00:03:49 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Garrett X-Patchwork-Id: 11011047 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 B64C51398 for ; Sat, 22 Jun 2019 00:06:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A499028BAD for ; Sat, 22 Jun 2019 00:06:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9845028B7B; Sat, 22 Jun 2019 00:06:18 +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 1D8EA28B7B for ; Sat, 22 Jun 2019 00:06:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726884AbfFVAEx (ORCPT ); Fri, 21 Jun 2019 20:04:53 -0400 Received: from mail-pf1-f201.google.com ([209.85.210.201]:46950 "EHLO mail-pf1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726883AbfFVAEx (ORCPT ); Fri, 21 Jun 2019 20:04:53 -0400 Received: by mail-pf1-f201.google.com with SMTP id a125so5316249pfa.13 for ; Fri, 21 Jun 2019 17:04:52 -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=PrHz11Fkohxiw/KAEo+rgP52AAtQBps1BcwB0CKo3qA=; b=JFwCQU3VW6N8fQbj5QygplLOospCB4WZ2mimGCOP6n+WOhSurcQpgYKoX9iw+cZ2K6 lfr0JV9a5FEYabcfgKFD2n6Oe6+2jlR6WwmG5IJWl6TSHGZbMzYhWldPaBoWulWPSt2Q n6nwq8yowPRfRHqRBFYCGiKeHVxfu8hk5JpXAy9ZSyUlF8mKnwxIGeYB/JaeT0mfCdVH jsnv53RcgGR+gNUsAtx76M4TpYdiprXQiVmjKDZ3WUiyWxBtk+IPYE4Tqu3u+i1Sl/Bv 2XAbs7AoszictGZ1JEiOzfUFw9KrUEgZ3ZX1sk/r5opiNHJKIXKeADFd8BG+XePh9aML 4/Mg== 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=PrHz11Fkohxiw/KAEo+rgP52AAtQBps1BcwB0CKo3qA=; b=PY7xZYPsLrF2knEUiZORDv+9/WCCLXY+mCHCHgFTspt+IgjSo9xwfv7CvDVQROqe2N KC5pUKWAF12Y19jrBW7QJb3JiknqJSUfYP0WNXC0lqHXELgmzCHdiI1Zv0DnWrLuBWpK prlA25Mb9A+F9Kn7f+vZPNtfJs5MDP5KtOjOPSYBddYseNH1XEFLeu9dG6zpBFw4b9dL KS45YQPkz7FmXXLnQOKDFcR+cNiS6vvRN4EGsDwK2gGscsN+6PUgKLmLA0HxEHF9wIfB wzNeQoKMfDsgDUPTJM0Hbj9blzgHGaw05qC1hfhDRVYU7qnZ/4rVEZ9xSbF0PJTXagBG 5nEA== X-Gm-Message-State: APjAAAV1eKSmgI+uTjzgGC+RFalq/YsNsBgGVaiMMEc0hRrw23z6G1lP 1wnc4T1QR+nN0wJIOWY7OtwWOSFYg5P1yGYFqy8H2g== X-Google-Smtp-Source: APXvYqxHPrRmaCO3xqjug+sv8qg9vhcJoBN5OdWTZlBjLu//lwEN4PjtXf5eSjG7q2BsNifXC/ydRjwvulqX9FFBZNjGHQ== X-Received: by 2002:a63:6146:: with SMTP id v67mr15959623pgb.116.1561161892042; Fri, 21 Jun 2019 17:04:52 -0700 (PDT) Date: Fri, 21 Jun 2019 17:03:49 -0700 In-Reply-To: <20190622000358.19895-1-matthewgarrett@google.com> Message-Id: <20190622000358.19895-21-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190622000358.19895-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH V34 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 cc: Thomas Gleixner cc: Steven Rostedt cc: Ingo Molnar cc: "H. Peter Anvin" cc: x86@kernel.org Reviewed-by: Kees Cook Reviewed-by: Thomas Gleixner --- 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 f6ae6830b341..6b9486baa2e9 100644 --- a/arch/x86/mm/testmmiotrace.c +++ b/arch/x86/mm/testmmiotrace.c @@ -7,6 +7,7 @@ #include #include #include +#include static unsigned long mmio_address; module_param_hw(mmio_address, ulong, iomem, 0); @@ -114,6 +115,10 @@ 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 88064d7f6827..c649cb91e762 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -93,6 +93,7 @@ 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 d03c4c296af7..cd86ed9f4d4b 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", };