From patchwork Thu Feb 22 21:33:04 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mimi Zohar X-Patchwork-Id: 10236433 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B4A0660224 for ; Thu, 22 Feb 2018 21:33:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id ACFC028DAF for ; Thu, 22 Feb 2018 21:33:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A05BB28E88; Thu, 22 Feb 2018 21:33:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1C27828F3E for ; Thu, 22 Feb 2018 21:33:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751476AbeBVVdY (ORCPT ); Thu, 22 Feb 2018 16:33:24 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:42500 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751158AbeBVVdW (ORCPT ); Thu, 22 Feb 2018 16:33:22 -0500 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w1MLTM64061327 for ; Thu, 22 Feb 2018 16:33:22 -0500 Received: from e06smtp11.uk.ibm.com (e06smtp11.uk.ibm.com [195.75.94.107]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ga25yrgsf-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 22 Feb 2018 16:33:21 -0500 Received: from localhost by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Thu, 22 Feb 2018 21:33:16 -0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w1MLXGaQ65994952; Thu, 22 Feb 2018 21:33:16 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AC7EE4C04A; Thu, 22 Feb 2018 21:26:51 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A36604C040; Thu, 22 Feb 2018 21:26:50 +0000 (GMT) Received: from dhcp-9-2-55-8.watson.ibm.com (unknown [9.2.55.8]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 22 Feb 2018 21:26:50 +0000 (GMT) From: Mimi Zohar To: linux-integrity@vger.kernel.org Cc: linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, Mimi Zohar , Miklos Szeredi , Seth Forshee , "Eric W . Biederman" , Dongsu Park , Alban Crequy , "Serge E. Hallyn" Subject: [PATCH v2 4/4] fuse: define the filesystem as untrusted Date: Thu, 22 Feb 2018 16:33:04 -0500 X-Mailer: git-send-email 2.7.5 In-Reply-To: <1519335184-17808-1-git-send-email-zohar@linux.vnet.ibm.com> References: <1519335184-17808-1-git-send-email-zohar@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18022221-0040-0000-0000-00000436B45C X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18022221-0041-0000-0000-000020D8CF63 Message-Id: <1519335184-17808-5-git-send-email-zohar@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2018-02-22_08:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=5 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1802220268 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Files on FUSE can change at any point in time without IMA being able to detect it. The file data read for the file signature verification could be totally different from what is subsequently read, making the signature verification useless. FUSE can be mounted by unprivileged users either today with fusermount installed with setuid, or soon with the upcoming patches to allow FUSE mounts in a non-init user namespace. This patch sets the SB_I_IMA_UNVERIFIABLE_SIGNATURE flag and when appropriate sets the SB_I_UNTRUSTED_MOUNTER flag. Signed-off-by: Mimi Zohar Cc: Miklos Szeredi Cc: Seth Forshee Cc: Eric W. Biederman Cc: Dongsu Park Cc: Alban Crequy Cc: "Serge E. Hallyn" --- fs/fuse/inode.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 624f18bbfd2b..ef309958e060 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1080,6 +1080,9 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) sb->s_maxbytes = MAX_LFS_FILESIZE; sb->s_time_gran = 1; sb->s_export_op = &fuse_export_operations; + sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE; + if (sb->s_user_ns != &init_user_ns) + sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER; file = fget(d.fd); err = -EINVAL;