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=-23.2 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,SPF_HELO_NONE,SPF_PASS,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 711ACC4361B for ; Sat, 12 Dec 2020 14:48:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 46C7C2076B for ; Sat, 12 Dec 2020 14:48:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2407453AbgLLOsZ (ORCPT ); Sat, 12 Dec 2020 09:48:25 -0500 Received: from linux.microsoft.com ([13.77.154.182]:54782 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726332AbgLLOsZ (ORCPT ); Sat, 12 Dec 2020 09:48:25 -0500 Received: from sequoia (162-237-133-238.lightspeed.rcsntx.sbcglobal.net [162.237.133.238]) by linux.microsoft.com (Postfix) with ESMTPSA id 43A5A20B717A; Sat, 12 Dec 2020 06:47:43 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 43A5A20B717A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1607784464; bh=7rvIg+C95XPCYPYAFneW2aePc3XSRuDLvoT56+NKeXk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QyUnRFPbnGYZvrLptKN9jY69HTvpMS5CaqSR1McFATSNefU01LhoR1c6hd8dXKIJQ MMIg+HlhiHyKnFXTTaHduplkzZL3G0b4QGqGFy/f9X/kVNE4nhaWgabmYy/Z99HLfc xEsur1DspVNmTLo24MDo1f3yDpVmFNcVoUc53a0k= Date: Sat, 12 Dec 2020 08:47:41 -0600 From: Tyler Hicks To: Tushar Sugandhi 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 Subject: Re: [PATCH v8 4/8] IMA: add policy rule to measure critical data Message-ID: <20201212144741.GH4951@sequoia> References: <20201211235807.30815-1-tusharsu@linux.microsoft.com> <20201211235807.30815-5-tusharsu@linux.microsoft.com> <20201212002500.GF4951@sequoia> <7e137e37-c195-1d16-05ef-56c2645fcc84@linux.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7e137e37-c195-1d16-05ef-56c2645fcc84@linux.microsoft.com> Precedence: bulk List-ID: On 2020-12-11 17:17:22, Tushar Sugandhi wrote: > > > 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. I understand the thinking that it isn't harmful in this patch but I think it is a bit cleaner to introduce the data_source policy language element and all of its backend support in the same patch. Please move it to the next patch. Thanks! Tyler > > + case CRITICAL_DATA: > + if (!rule->data_source) > + return true; > + > + opt_list = rule->data_source; > + break; > > > ~Tushar >