From patchwork Wed Apr 5 17:14:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Berger X-Patchwork-Id: 13202298 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87EB8C77B6C for ; Wed, 5 Apr 2023 17:15:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232770AbjDERPJ (ORCPT ); Wed, 5 Apr 2023 13:15:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34224 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229748AbjDERPG (ORCPT ); Wed, 5 Apr 2023 13:15:06 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C08DA1BEF; Wed, 5 Apr 2023 10:15:05 -0700 (PDT) Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 335GG6GM013112; Wed, 5 Apr 2023 17:15:04 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding; s=pp1; bh=xdPANpjtlbwea8smzHbacqN4g1Ruy2zYgHhQtcKL4jA=; b=JviavfdghGpxFybYoZ5PlrAS6QH2tK6y0r0h+eXId+HQSVyuZwFsAE51ZdMf1ff8IoSY P++/zzbiTHnTDBH9nzhlqIg3PrXzCqG3Ag4Ui7vYjJ+SYDACo3jAydx7qX4BAmris178 pSHQRQqmageLgFAvtA+6VddGcD5/HFH4snG+444FBWx9UBBRgbMxO4wf0+V11IoVldbJ fUBcS1Y+CJcWyp+IS+74gxvt0hoNYLjeLOYYde0GmAJIDbwNDfVjwLU3s2pSjWN+I7DV 8BrNIpuZsqc1J5HzEP9DCeb9eWi6kAyGm4xsmky9G580xQpWuJGp80zwxn/Zy53Yj8r8 GA== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com (PPS) with ESMTPS id 3ps8w7yu2n-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 05 Apr 2023 17:15:04 +0000 Received: from m0098416.ppops.net (m0098416.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 335Gk6am002751; Wed, 5 Apr 2023 17:15:03 GMT Received: from ppma02dal.us.ibm.com (a.bd.3ea9.ip4.static.sl-reverse.com [169.62.189.10]) by mx0b-001b2d01.pphosted.com (PPS) with ESMTPS id 3ps8w7yu29-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 05 Apr 2023 17:15:03 +0000 Received: from pps.filterd (ppma02dal.us.ibm.com [127.0.0.1]) by ppma02dal.us.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 335H1GMO031516; Wed, 5 Apr 2023 17:15:03 GMT Received: from smtprelay02.dal12v.mail.ibm.com ([9.208.130.97]) by ppma02dal.us.ibm.com (PPS) with ESMTPS id 3ppc88d3y0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 05 Apr 2023 17:15:02 +0000 Received: from smtpav02.wdc07v.mail.ibm.com (smtpav02.wdc07v.mail.ibm.com [10.39.53.229]) by smtprelay02.dal12v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 335HF1hV36307508 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 5 Apr 2023 17:15:01 GMT Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 17F085805C; Wed, 5 Apr 2023 17:15:01 +0000 (GMT) Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2D01B58059; Wed, 5 Apr 2023 17:15:00 +0000 (GMT) Received: from sbct-3.pok.ibm.com (unknown [9.47.158.153]) by smtpav02.wdc07v.mail.ibm.com (Postfix) with ESMTP; Wed, 5 Apr 2023 17:15:00 +0000 (GMT) From: Stefan Berger To: zohar@linux.ibm.com, linux-integrity@vger.kernel.org, miklos@szeredi.hu Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org, amir73il@gmail.com, Stefan Berger Subject: [PATCH] overlayfs: Trigger file re-evaluation by IMA / EVM after writes Date: Wed, 5 Apr 2023 13:14:49 -0400 Message-Id: <20230405171449.4064321-1-stefanb@linux.ibm.com> X-Mailer: git-send-email 2.39.1 MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: I-u9B3_Iu8NUUSka9TVqB0TEA3acKn1L X-Proofpoint-ORIG-GUID: usiMNPTQycmGVGH7XZb5S6smuMFo-bqs X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-04-05_11,2023-04-05_01,2023-02-09_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 impostorscore=0 lowpriorityscore=0 clxscore=1011 phishscore=0 spamscore=0 bulkscore=0 adultscore=0 malwarescore=0 suspectscore=0 mlxlogscore=999 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2303200000 definitions=main-2304050154 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Overlayfs fails to notify IMA / EVM about file content modifications and therefore IMA-appraised files may execute even though their file signature does not validate against the changed hash of the file anymore. To resolve this issue, add a call to integrity_notify_change() to the ovl_release() function to notify the integrity subsystem about file changes. The set flag triggers the re-evaluation of the file by IMA / EVM once the file is accessed again. Signed-off-by: Stefan Berger Reported-by: Stefan Berger Signed-off-by: Jeff Layton Tested-by: Stefan Berger --- fs/overlayfs/file.c | 4 ++++ include/linux/integrity.h | 6 ++++++ security/integrity/iint.c | 13 +++++++++++++ 3 files changed, 23 insertions(+) diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 6011f955436b..19b8f4bcc18c 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -13,6 +13,7 @@ #include #include #include +#include #include "overlayfs.h" struct ovl_aio_req { @@ -169,6 +170,9 @@ static int ovl_open(struct inode *inode, struct file *file) static int ovl_release(struct inode *inode, struct file *file) { + if (file->f_flags & O_ACCMODE) + integrity_notify_change(inode); + fput(file->private_data); return 0; diff --git a/include/linux/integrity.h b/include/linux/integrity.h index 2ea0f2f65ab6..cefdeccc1619 100644 --- a/include/linux/integrity.h +++ b/include/linux/integrity.h @@ -23,6 +23,7 @@ enum integrity_status { #ifdef CONFIG_INTEGRITY extern struct integrity_iint_cache *integrity_inode_get(struct inode *inode); extern void integrity_inode_free(struct inode *inode); +extern void integrity_notify_change(struct inode *inode); extern void __init integrity_load_keys(void); #else @@ -37,6 +38,11 @@ static inline void integrity_inode_free(struct inode *inode) return; } +static inline void integrity_notify_change(struct inode *inode) +{ + return; +} + static inline void integrity_load_keys(void) { } diff --git a/security/integrity/iint.c b/security/integrity/iint.c index 8638976f7990..70d2d716f3ae 100644 --- a/security/integrity/iint.c +++ b/security/integrity/iint.c @@ -85,6 +85,19 @@ static void iint_free(struct integrity_iint_cache *iint) kmem_cache_free(iint_cache, iint); } +void integrity_notify_change(struct inode *inode) +{ + struct integrity_iint_cache *iint; + + if (!IS_IMA(inode)) + return; + + iint = integrity_iint_find(inode); + if (iint) + set_bit(IMA_CHANGE_XATTR, &iint->atomic_flags); +} +EXPORT_SYMBOL_GPL(integrity_notify_change); + /** * integrity_inode_get - find or allocate an iint associated with an inode * @inode: pointer to the inode