From patchwork Tue Aug 20 00:17:55 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Garrett X-Patchwork-Id: 11102387 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3F7531395 for ; Tue, 20 Aug 2019 00:19:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1509322CF7 for ; Tue, 20 Aug 2019 00:19:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Mhh4cPNk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729118AbfHTATB (ORCPT ); Mon, 19 Aug 2019 20:19:01 -0400 Received: from mail-vs1-f74.google.com ([209.85.217.74]:50121 "EHLO mail-vs1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729109AbfHTATA (ORCPT ); Mon, 19 Aug 2019 20:19:00 -0400 Received: by mail-vs1-f74.google.com with SMTP id t76so1385005vst.16 for ; Mon, 19 Aug 2019 17:19:00 -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=WRMzqxGXLNI0SsBdZY8cEvaiXgaE0VA439c0Hio6O3c=; b=Mhh4cPNkmy8sQQ8Xxa6AAQ9jY+vx5NznNoSQsXjJgvPnFoVdCPwv1xnIxLGy8wXOGa Y+QauLaf0LDbBMzar7QnmBa5VhZCshx710U0wHANb09ggoNAPyH9zceRsKiRbEGz0qlu QvTXKIWp1YhLEhIVJ+uBGGcUZsogr6LaPafLxs4ZMANGUX6XfXwcbGuGD0umHIP0TbIE ykMq+1ZXLAn6HbdHiF4uA4bH4kYP3p2OcaBjMtd6lwrj/dSTbS6ccppsiSHGxtEyegpB aDdOBJexX3QW8dhwf9EjxMlcSOXlKXlVj4ox4W2c39ULGab0VcK2dYwnTYmdPBPhuzBs xM1Q== 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=WRMzqxGXLNI0SsBdZY8cEvaiXgaE0VA439c0Hio6O3c=; b=EhWUFaO5Gzj06PjrtlBMPqoLRVlGJ181/kwSb3MIMcNt1b/4VqRmGF9A609fVCqSEO WgZwapz/Mk7J8pkNINbruWJU0DiY02J9hJPmXUsnNKrnLdM026sXK/zQNbOOfFo4iBF3 S4cGbO/P/pDJAs6QrGcgdwBgI9oXhoXI2KWQnEXRdtfyoIM3ToKGSl0mTHzY8vrB/hEz X2Jl0wuOKeE6DRirAj41hGvKLhjKt6R09+JAF2e1TsGGf8C2Z6uFPacVlbBmV0HchClP SexvZSRR0NW7fcvzlR++NXLVug1BOZZJHn068w+dxsyrUTbQP9ALRhv9+rhTnkU5KBpS uTBg== X-Gm-Message-State: APjAAAX846sUVnlBPUQL1FSE+/+d7yBEbYCNF50kNVJpUGmbCwrZKikY 9ngdW+1MrA0pEyjQrM4GBo4uW1pGamogr8M4rTtwJQ== X-Google-Smtp-Source: APXvYqyV4Kgwvl5pQht/U4WWNO2ngHwajMUTquOJOpL/jf7OovZEbp24SlhZhz06vIk33GR7iA5I4Do0Ql2vGMvUJiqKbA== X-Received: by 2002:a1f:1654:: with SMTP id 81mr9237922vkw.49.1566260339513; Mon, 19 Aug 2019 17:18:59 -0700 (PDT) Date: Mon, 19 Aug 2019 17:17:55 -0700 In-Reply-To: <20190820001805.241928-1-matthewgarrett@google.com> Message-Id: <20190820001805.241928-20-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190820001805.241928-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.23.0.rc1.153.gdeed80330f-goog Subject: [PATCH V40 19/29] lockdown: Lock down module params that specify hardware parameters (eg. ioport) 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 , Alan Cox , Matthew Garrett , Kees Cook , Jessica Yu Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: From: David Howells Provided an annotation for module parameters that specify hardware parameters (such as io ports, iomem addresses, irqs, dma channels, fixed dma buffers and other types). Suggested-by: Alan Cox Signed-off-by: David Howells Signed-off-by: Matthew Garrett Reviewed-by: Kees Cook Cc: Jessica Yu Signed-off-by: James Morris Acked-by: Jessica Yu --- include/linux/security.h | 1 + kernel/params.c | 21 ++++++++++++++++----- security/lockdown/lockdown.c | 1 + 3 files changed, 18 insertions(+), 5 deletions(-) diff --git a/include/linux/security.h b/include/linux/security.h index b4a85badb03a..1a3404f9c060 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -113,6 +113,7 @@ enum lockdown_reason { LOCKDOWN_ACPI_TABLES, LOCKDOWN_PCMCIA_CIS, LOCKDOWN_TIOCSSERIAL, + LOCKDOWN_MODULE_PARAMETERS, LOCKDOWN_INTEGRITY_MAX, LOCKDOWN_CONFIDENTIALITY_MAX, }; diff --git a/kernel/params.c b/kernel/params.c index cf448785d058..8e56f8b12d8f 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -12,6 +12,7 @@ #include #include #include +#include #ifdef CONFIG_SYSFS /* Protects all built-in parameters, modules use their own param_lock */ @@ -96,13 +97,19 @@ bool parameq(const char *a, const char *b) return parameqn(a, b, strlen(a)+1); } -static void param_check_unsafe(const struct kernel_param *kp) +static bool param_check_unsafe(const struct kernel_param *kp) { + if (kp->flags & KERNEL_PARAM_FL_HWPARAM && + security_locked_down(LOCKDOWN_MODULE_PARAMETERS)) + return false; + if (kp->flags & KERNEL_PARAM_FL_UNSAFE) { pr_notice("Setting dangerous option %s - tainting kernel\n", kp->name); add_taint(TAINT_USER, LOCKDEP_STILL_OK); } + + return true; } static int parse_one(char *param, @@ -132,8 +139,10 @@ static int parse_one(char *param, pr_debug("handling %s with %p\n", param, params[i].ops->set); kernel_param_lock(params[i].mod); - param_check_unsafe(¶ms[i]); - err = params[i].ops->set(val, ¶ms[i]); + if (param_check_unsafe(¶ms[i])) + err = params[i].ops->set(val, ¶ms[i]); + else + err = -EPERM; kernel_param_unlock(params[i].mod); return err; } @@ -553,8 +562,10 @@ static ssize_t param_attr_store(struct module_attribute *mattr, return -EPERM; kernel_param_lock(mk->mod); - param_check_unsafe(attribute->param); - err = attribute->param->ops->set(buf, attribute->param); + if (param_check_unsafe(attribute->param)) + err = attribute->param->ops->set(buf, attribute->param); + else + err = -EPERM; kernel_param_unlock(mk->mod); if (!err) return len; diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c index 771c77f9c04a..0fa434294667 100644 --- a/security/lockdown/lockdown.c +++ b/security/lockdown/lockdown.c @@ -28,6 +28,7 @@ static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = { [LOCKDOWN_ACPI_TABLES] = "modifying ACPI tables", [LOCKDOWN_PCMCIA_CIS] = "direct PCMCIA CIS storage", [LOCKDOWN_TIOCSSERIAL] = "reconfiguration of serial port IO", + [LOCKDOWN_MODULE_PARAMETERS] = "unsafe module parameters", [LOCKDOWN_INTEGRITY_MAX] = "integrity", [LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality", };