Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751598AbdLXFMW (ORCPT ); Sun, 24 Dec 2017 00:12:22 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:55376 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751177AbdLXFMT (ORCPT ); Sun, 24 Dec 2017 00:12:19 -0500 Subject: Re: [PATCH 11/11] evm: Don't update hmacs in user ns mounts From: Mimi Zohar To: "Serge E. Hallyn" , Dongsu Park Cc: linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, Alban Crequy , "Eric W . Biederman" , Miklos Szeredi , Seth Forshee , Sargun Dhillon , linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, James Morris Date: Sun, 24 Dec 2017 00:12:08 -0500 In-Reply-To: <20171223040348.GK6837@mail.hallyn.com> References: <1f2233a1a028f1eb1e9bea7d06efa6d34e69e752.1512041070.git.dongsu@kinvolk.io> <20171223040348.GK6837@mail.hallyn.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-cbid: 17122405-0020-0000-0000-000003E34F25 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17122405-0021-0000-0000-000042747178 Message-Id: <1514092328.5221.116.camel@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-12-23_15:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 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-1712240071 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1780 Lines: 52 Hi Serge, On Fri, 2017-12-22 at 22:03 -0600, Serge E. Hallyn wrote: > On Fri, Dec 22, 2017 at 03:32:35PM +0100, Dongsu Park wrote: > > From: Seth Forshee > > > > The kernel should not calculate new hmacs for mounts done by > > non-root users. Update evm_calc_hmac_or_hash() to refuse to > > calculate new hmacs for mounts for non-init user namespaces. > > > > Cc: linux-integrity@vger.kernel.org > > Cc: linux-security-module@vger.kernel.org > > Cc: linux-kernel@vger.kernel.org > > Cc: James Morris > > Cc: Mimi Zohar > > Hi Mimi, > > does this change seem sufficient to you? I think this is the correct behavior in the context of fuse file systems.  This patch, the "ima: define a new policy option named force" patch, and an updated IMA policy should be upstreamed together.  The cover letter should provide the motivation for these patches. Mimi > > > Cc: "Serge E. Hallyn" > > Signed-off-by: Seth Forshee > > Signed-off-by: Dongsu Park > > --- > > security/integrity/evm/evm_crypto.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c > > index bcd64baf..729f4545 100644 > > --- a/security/integrity/evm/evm_crypto.c > > +++ b/security/integrity/evm/evm_crypto.c > > @@ -190,7 +190,8 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry, > > int error; > > int size; > > > > - if (!(inode->i_opflags & IOP_XATTR)) > > + if (!(inode->i_opflags & IOP_XATTR) || > > + inode->i_sb->s_user_ns != &init_user_ns) > > return -EOPNOTSUPP; > > > > desc = init_desc(type); > > -- > > 2.13.6 >