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=-24.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,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 6E1B1C1B0D8 for ; Sat, 12 Dec 2020 01:19:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 37E9023406 for ; Sat, 12 Dec 2020 01:19:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406040AbgLLBSd (ORCPT ); Fri, 11 Dec 2020 20:18:33 -0500 Received: from linux.microsoft.com ([13.77.154.182]:36596 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405263AbgLLBSF (ORCPT ); Fri, 11 Dec 2020 20:18:05 -0500 Received: from [192.168.86.31] (c-71-197-163-6.hsd1.wa.comcast.net [71.197.163.6]) by linux.microsoft.com (Postfix) with ESMTPSA id CC99920B717A; Fri, 11 Dec 2020 17:17:23 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com CC99920B717A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1607735844; bh=A4PmgqhxEBaCumFsp+Oy5gmw7S+43Wu3aaPwD4M4t5s=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=FbcRuX7Njy+hxdgmCkCmR0utiQhTYgo3xRsaarpPkEIgv1dZAujzr1Q32R9LdccCe GAxn1Zsn6uTaO/Cp9W4cpjeS/fht6F9+GoddjMF30WVD5kj/vZALN56VH5kGopqHO7 Y6TvMmFy8dfflgySU/WDtb/I6+vLL8JeXTEHzJ04= Subject: Re: [PATCH v8 4/8] IMA: add policy rule to measure critical data To: Tyler Hicks Cc: zohar@linux.ibm.com, stephen.smalley.work@gmail.com, casey@schaufler-ca.com, agk@redhat.com, snitzer@redhat.com, gmazyland@gmail.com, paul@paul-moore.com, sashal@kernel.org, jmorris@namei.org, nramas@linux.microsoft.com, 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: <20201211235807.30815-1-tusharsu@linux.microsoft.com> <20201211235807.30815-5-tusharsu@linux.microsoft.com> <20201212002500.GF4951@sequoia> From: Tushar Sugandhi Message-ID: <7e137e37-c195-1d16-05ef-56c2645fcc84@linux.microsoft.com> Date: Fri, 11 Dec 2020 17:17:22 -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: <20201212002500.GF4951@sequoia> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On 2020-12-11 4:25 p.m., Tyler Hicks wrote: > On 2020-12-11 15:58:03, Tushar Sugandhi wrote: >> A new IMA policy rule is needed for the IMA hook >> ima_measure_critical_data() and the corresponding func CRITICAL_DATA for >> measuring the input buffer. The policy rule should ensure the buffer >> would get measured only when the policy rule allows the action. The >> policy rule should also support the necessary constraints (flags etc.) >> for integrity critical buffer data measurements. >> >> Add a policy rule to define the constraints for restricting integrity >> critical data measurements. >> >> Signed-off-by: Tushar Sugandhi >> --- >> Documentation/ABI/testing/ima_policy | 2 +- >> security/integrity/ima/ima_policy.c | 34 ++++++++++++++++++++++++---- >> 2 files changed, 31 insertions(+), 5 deletions(-) >> >> diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy >> index e35263f97fc1..6ec7daa87cba 100644 >> --- a/Documentation/ABI/testing/ima_policy >> +++ b/Documentation/ABI/testing/ima_policy >> @@ -32,7 +32,7 @@ Description: >> func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK]MODULE_CHECK] >> [FIRMWARE_CHECK] >> [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK] >> - [KEXEC_CMDLINE] [KEY_CHECK] >> + [KEXEC_CMDLINE] [KEY_CHECK] [CRITICAL_DATA] >> mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND] >> [[^]MAY_EXEC] >> fsmagic:= hex value >> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c >> index a09d1a41a290..07116ff35c25 100644 >> --- a/security/integrity/ima/ima_policy.c >> +++ b/security/integrity/ima/ima_policy.c >> @@ -85,6 +85,7 @@ struct ima_rule_entry { >> } lsm[MAX_LSM_RULES]; >> char *fsname; >> struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */ >> + struct ima_rule_opt_list *data_source; /* Measure data from this source */ > > Argh, there are still some more instances of data_source sneaking into > this patch too early instead of waiting until the next patch. > I kept it purposefully in this patch so that the "case CRITICAL_DATA:" could be properly defined. Also, my impression was rule->data_source is not part of the user facing policy. Whereas IMA_DATA_SOURCE, Opt_data_source, data_source=%s are. That's why they are part of Patch #5. Patch #5 IMA: limit critical data measurement based on a label >> struct ima_template_desc *template; >> }; >> >> @@ -479,6 +480,12 @@ static bool ima_match_rule_data(struct ima_rule_entry *rule, >> >> opt_list = rule->keyrings; >> break; >> + case CRITICAL_DATA: >> + if (!rule->data_source) >> + return true; >> + >> + opt_list = rule->data_source; >> + break; > > I guess this case should unconditionally return true in this patch and > then the include this additional logic in the next patch. > > Sorry, I missed these on my last review. > No worries. As I mentioned above, I kept it purposefully in this patch since my impression was rule->data_source is not part of the user facing policy. But I can simply return true here as you suggested, and move the logic to the next patch. + case CRITICAL_DATA: + if (!rule->data_source) + return true; + + opt_list = rule->data_source; + break; ~Tushar