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[23.128.96.18]) by mx.google.com with ESMTP id w6si9052736edv.249.2020.12.13.05.56.24; Sun, 13 Dec 2020 05:56:47 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linux.microsoft.com header.s=default header.b=glZ1RS5w; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linux.microsoft.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2407289AbgLLA0M (ORCPT + 99 others); Fri, 11 Dec 2020 19:26:12 -0500 Received: from linux.microsoft.com ([13.77.154.182]:58238 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437719AbgLLAZo (ORCPT ); Fri, 11 Dec 2020 19:25:44 -0500 Received: from sequoia (162-237-133-238.lightspeed.rcsntx.sbcglobal.net [162.237.133.238]) by linux.microsoft.com (Postfix) with ESMTPSA id 206A320B7185; Fri, 11 Dec 2020 16:25:02 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 206A320B7185 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1607732703; bh=XpHqSBbB4XEdjlCvzq+Uh067HqdVGkrcUciB2GguQ5o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=glZ1RS5wuZUAUfbHLuAlO0ymMWmyUgdOSZ/PpV+WhzCq+79NiMaPuKDLC7kU+BJZX cs4PiDuuYIc6x4P6PDL2b+24ZCWKflsoPQ4oxunuL4Z23/YSRO9OmwpgHlMYn2OfI0 HoGdRu25BlEu8DCKOZPecMwTHTod1uaSt7G0yQi0= Date: Fri, 11 Dec 2020 18:25:00 -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: <20201212002500.GF4951@sequoia> References: <20201211235807.30815-1-tusharsu@linux.microsoft.com> <20201211235807.30815-5-tusharsu@linux.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201211235807.30815-5-tusharsu@linux.microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > 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. Tyler > default: > return false; > } > @@ -515,13 +522,19 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, > { > int i; > > - if (func == KEY_CHECK) { > - return (rule->flags & IMA_FUNC) && (rule->func == func) && > - ima_match_rule_data(rule, func_data, cred); > - } > if ((rule->flags & IMA_FUNC) && > (rule->func != func && func != POST_SETATTR)) > return false; > + > + switch (func) { > + case KEY_CHECK: > + case CRITICAL_DATA: > + return ((rule->func == func) && > + ima_match_rule_data(rule, func_data, cred)); > + default: > + break; > + } > + > if ((rule->flags & IMA_MASK) && > (rule->mask != mask && func != POST_SETATTR)) > return false; > @@ -1116,6 +1129,17 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) > if (ima_rule_contains_lsm_cond(entry)) > return false; > > + break; > + case CRITICAL_DATA: > + if (entry->action & ~(MEASURE | DONT_MEASURE)) > + return false; > + > + if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR)) > + return false; > + > + if (ima_rule_contains_lsm_cond(entry)) > + return false; > + > break; > default: > return false; > @@ -1248,6 +1272,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) > else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) && > strcmp(args[0].from, "KEY_CHECK") == 0) > entry->func = KEY_CHECK; > + else if (strcmp(args[0].from, "CRITICAL_DATA") == 0) > + entry->func = CRITICAL_DATA; > else > result = -EINVAL; > if (!result) > -- > 2.17.1 >