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=-18.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1,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 1FC48C2D0A3 for ; Fri, 6 Nov 2020 15:37:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BAF2D22202 for ; Fri, 6 Nov 2020 15:37:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="QT3DxheG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727521AbgKFPhS (ORCPT ); Fri, 6 Nov 2020 10:37:18 -0500 Received: from linux.microsoft.com ([13.77.154.182]:58726 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726422AbgKFPhS (ORCPT ); Fri, 6 Nov 2020 10:37:18 -0500 Received: from [192.168.0.104] (c-73-42-176-67.hsd1.wa.comcast.net [73.42.176.67]) by linux.microsoft.com (Postfix) with ESMTPSA id 39B5020B4905; Fri, 6 Nov 2020 07:37:17 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 39B5020B4905 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1604677037; bh=q4PevNfxu74JV0KEYqy84LCv65lpjN/rPTqrzxIlBks=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=QT3DxheGucb03zVsRchRm/X0Wt7iWczuLLZozJm37jmzqwPGFuvKUOP42DF525xcc 0gcgEe5XHYKTTCxNEdXlGOxdKoYnQGP8Mz3XIjFW9vhEBiK9RNqdXnz4wUDhugXoqx XjPjC6gEWB/LHZNMWi7vgi2eqvOMLn2m5Mw5Hl+M= Subject: Re: [PATCH v5 6/7] IMA: add critical_data to the built-in policy rules To: Mimi Zohar , Tushar Sugandhi , stephen.smalley.work@gmail.com, casey@schaufler-ca.com, agk@redhat.com, snitzer@redhat.com, gmazyland@gmail.com, paul@paul-moore.com Cc: tyhicks@linux.microsoft.com, sashal@kernel.org, jmorris@namei.org, linux-integrity@vger.kernel.org, selinux@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com References: <20201101222626.6111-1-tusharsu@linux.microsoft.com> <20201101222626.6111-7-tusharsu@linux.microsoft.com> <7219f4404bc1bed6eb090b94363c283ec3266a17.camel@linux.ibm.com> From: Lakshmi Ramasubramanian Message-ID: Date: Fri, 6 Nov 2020 07:37:16 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <7219f4404bc1bed6eb090b94363c283ec3266a17.camel@linux.ibm.com> Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org On 11/6/20 7:24 AM, Mimi Zohar wrote: Hi Mimi, Thanks for reviewing the patches. > Hi Lakshmi, Tushar, > > This patch defines a new critical_data builtin policy. Please update > the Subject line. > > On Sun, 2020-11-01 at 14:26 -0800, Tushar Sugandhi wrote: >> From: Lakshmi Ramasubramanian >> >> The IMA hook to measure kernel critical data, namely >> ima_measure_critical_data(), could be called before a custom IMA policy >> is loaded. For example, SELinux calls ima_measure_critical_data() to >> measure its state and policy when they are initialized. This occurs >> before a custom IMA policy is loaded, and hence IMA hook will not >> measure the data. A built-in policy is therefore needed to measure >> critical data provided by callers before a custom IMA policy is loaded. > > ^Define a new critical data builtin policy to allow measuring early > kernel integrity critical data before a custom IMA policy is loaded. I will add the above line in the patch description. > > Either remove the references to SELinux or move this patch after the > subsequent patch which measures SELinux critical data. I will remove the reference to SELinux. I think it would be better to have this patch before the SELinux measurement patch. > >> >> Add CRITICAL_DATA to built-in IMA rules if the kernel command line >> contains "ima_policy=critical_data". Set the IMA template for this rule >> to "ima-buf" since ima_measure_critical_data() measures a buffer. >> >> Signed-off-by: Lakshmi Ramasubramanian > >> --- >> security/integrity/ima/ima_policy.c | 32 +++++++++++++++++++++++++++++ >> 1 file changed, 32 insertions(+) >> >> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c >> index ec99e0bb6c6f..dc8fe969d3fe 100644 >> --- a/security/integrity/ima/ima_policy.c >> +++ b/security/integrity/ima/ima_policy.c > >> @@ -875,6 +884,29 @@ void __init ima_init_policy(void) >> ARRAY_SIZE(default_appraise_rules), >> IMA_DEFAULT_POLICY); >> >> + if (ima_use_critical_data) { >> + template = lookup_template_desc("ima-buf"); >> + if (!template) { >> + ret = -EINVAL; >> + goto out; >> + } >> + >> + ret = template_desc_init_fields(template->fmt, >> + &(template->fields), >> + &(template->num_fields)); > > The default IMA template when measuring buffer data is "ima_buf". Is > there a reason for allocating and initializing it here and not > deferring it until process_buffer_measurement()? > You are right - good catch. I will remove the above and validate. thanks, -lakshmi > >> + if (ret) >> + goto out; >> + >> + critical_data_rules[0].template = template; >> + add_rules(critical_data_rules, >> + ARRAY_SIZE(critical_data_rules), >> + IMA_DEFAULT_POLICY); >> + } >> + >> +out: >> + if (ret) >> + pr_err("%s failed, result: %d\n", __func__, ret); >> + >> ima_update_policy_flag(); >> } >> >