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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 0853CC433DF for ; Thu, 25 Jun 2020 21:52:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF5E520789 for ; Thu, 25 Jun 2020 21:52:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390635AbgFYVwH (ORCPT ); Thu, 25 Jun 2020 17:52:07 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:63924 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389705AbgFYVwG (ORCPT ); Thu, 25 Jun 2020 17:52:06 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 05PLVvxT189559; Thu, 25 Jun 2020 17:52:01 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 31vts13ecq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 25 Jun 2020 17:52:01 -0400 Received: from m0098409.ppops.net (m0098409.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 05PLVvwj189585; Thu, 25 Jun 2020 17:52:01 -0400 Received: from ppma06fra.de.ibm.com (48.49.7a9f.ip4.static.sl-reverse.com [159.122.73.72]) by mx0a-001b2d01.pphosted.com with ESMTP id 31vts13ec1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 25 Jun 2020 17:52:00 -0400 Received: from pps.filterd (ppma06fra.de.ibm.com [127.0.0.1]) by ppma06fra.de.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 05PLpweL022074; Thu, 25 Jun 2020 21:51:58 GMT Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by ppma06fra.de.ibm.com with ESMTP id 31uusps2un-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 25 Jun 2020 21:51:58 +0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 05PLpuEb41484542 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 25 Jun 2020 21:51:56 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1F6814C059; Thu, 25 Jun 2020 21:51:56 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DDF504C046; Thu, 25 Jun 2020 21:51:54 +0000 (GMT) Received: from localhost.localdomain (unknown [9.85.142.225]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 25 Jun 2020 21:51:54 +0000 (GMT) Message-ID: <1593121914.27152.411.camel@linux.ibm.com> Subject: Re: [PATCH 05/12] ima: Fail rule parsing when buffer hook functions have an invalid action From: Mimi Zohar To: Tyler Hicks , Dmitry Kasatkin Cc: James Morris , "Serge E . Hallyn" , Lakshmi Ramasubramanian , Prakhar Srivastava , linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org Date: Thu, 25 Jun 2020 17:51:54 -0400 In-Reply-To: <20200623003236.830149-6-tyhicks@linux.microsoft.com> References: <20200623003236.830149-1-tyhicks@linux.microsoft.com> <20200623003236.830149-6-tyhicks@linux.microsoft.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216,18.0.687 definitions=2020-06-25_16:2020-06-25,2020-06-25 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 cotscore=-2147483648 adultscore=0 mlxscore=0 malwarescore=0 clxscore=1015 phishscore=0 suspectscore=0 spamscore=0 impostorscore=0 priorityscore=1501 mlxlogscore=999 lowpriorityscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006250124 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Mon, 2020-06-22 at 19:32 -0500, Tyler Hicks wrote: > Buffer based hook functions, such as KEXEC_CMDLINE and KEY_CHECK, can > only measure. The process_buffer_measurement() function quietly ignores > all actions except measure so make this behavior clear at the time of > policy load. > > The parsing of the keyrings conditional had a check to ensure that it > was only specified with measure actions but the check should be on the > hook function and not the keyrings conditional since > "appraise func=KEY_CHECK" is not a valid rule. > > Fixes: b0935123a183 ("IMA: Define a new hook to measure the kexec boot command line arguments") > Fixes: 5808611cccb2 ("IMA: Add KEY_CHECK func to measure keys") > Signed-off-by: Tyler Hicks > --- > security/integrity/ima/ima_policy.c | 36 +++++++++++++++++++++++++++-- > 1 file changed, 34 insertions(+), 2 deletions(-) > > diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c > index ee5152ecd3d9..ecc234b956a2 100644 > --- a/security/integrity/ima/ima_policy.c > +++ b/security/integrity/ima/ima_policy.c > @@ -979,6 +979,39 @@ static void check_template_modsig(const struct ima_template_desc *template) > #undef MSG > } > > +static bool ima_validate_rule(struct ima_rule_entry *entry) > +{ > + if (entry->action == UNKNOWN) > + return false; > + > + if (entry->flags & IMA_FUNC) { > + switch (entry->func) { > + case NONE: > + case FILE_CHECK: > + case MMAP_CHECK: > + case BPRM_CHECK: > + case CREDS_CHECK: > + case POST_SETATTR: > + case MODULE_CHECK: > + case FIRMWARE_CHECK: > + case KEXEC_KERNEL_CHECK: > + case KEXEC_INITRAMFS_CHECK: > + case POLICY_CHECK: > + break; > + case KEXEC_CMDLINE: > + case KEY_CHECK: > + if (entry->action & ~(MEASURE | DONT_MEASURE)) > + return false; > + > + break; > + default: > + return false; > + } > + } > + > + return true; > +} > + Good idea.  There are a couple of other examples that could be cleaned up as well.  For example, for performance reasons "appraise_flag=check_blacklist" is limited to files with appended signatures, like kernel modules and the kexec kernel image (OpenPower). Mimi