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[23.128.96.18]) by mx.google.com with ESMTP id c15si1541157ejr.343.2020.05.14.03.14.21; Thu, 14 May 2020 03:14:44 -0700 (PDT) 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; 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=fail (p=NONE sp=NONE dis=NONE) header.from=aculab.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726070AbgENKMk convert rfc822-to-8bit (ORCPT + 99 others); Thu, 14 May 2020 06:12:40 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]:57360 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726050AbgENKMj (ORCPT ); Thu, 14 May 2020 06:12:39 -0400 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-29-y0BDf4GNOjC8TdKy0usypQ-1; Thu, 14 May 2020 11:12:35 +0100 X-MC-Unique: y0BDf4GNOjC8TdKy0usypQ-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Thu, 14 May 2020 11:12:34 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Thu, 14 May 2020 11:12:34 +0100 From: David Laight To: 'Kees Cook' , Stephen Smalley CC: =?iso-8859-1?Q?Micka=EBl_Sala=FCn?= , linux-kernel , Aleksa Sarai , "Alexei Starovoitov" , Al Viro , "Andy Lutomirski" , Christian Heimes , "Daniel Borkmann" , Deven Bowers , Eric Chiang , Florian Weimer , James Morris , "Jan Kara" , Jann Horn , Jonathan Corbet , Lakshmi Ramasubramanian , Matthew Garrett , Matthew Wilcox , Michael Kerrisk , =?iso-8859-1?Q?Micka=EBl_Sala=FCn?= , Mimi Zohar , =?iso-8859-1?Q?Philippe_Tr=E9buchet?= , "Scott Shell" , Sean Christopherson , Shuah Khan , Steve Dower , Steve Grubb , Thibaut Sautereau , Vincent Strubel , "kernel-hardening@lists.openwall.com" , "linux-api@vger.kernel.org" , "linux-integrity@vger.kernel.org" , LSM List , Linux FS Devel Subject: RE: [PATCH v5 3/6] fs: Enable to enforce noexec mounts or file exec through O_MAYEXEC Thread-Topic: [PATCH v5 3/6] fs: Enable to enforce noexec mounts or file exec through O_MAYEXEC Thread-Index: AQHWKZyBpmhTpEnBl0+f5QrKafolWKinXOJQ Date: Thu, 14 May 2020 10:12:34 +0000 Message-ID: <33eba9f60af54f1585ba82af73be4eb2@AcuMS.aculab.com> References: <20200505153156.925111-1-mic@digikod.net> <20200505153156.925111-4-mic@digikod.net> <202005131525.D08BFB3@keescook> <202005132002.91B8B63@keescook> In-Reply-To: <202005132002.91B8B63@keescook> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kees Cook > Sent: 14 May 2020 04:05 > On Wed, May 13, 2020 at 04:27:39PM -0700, Kees Cook wrote: > > Like, couldn't just the entire thing just be: > > > > diff --git a/fs/namei.c b/fs/namei.c > > index a320371899cf..0ab18e19f5da 100644 > > --- a/fs/namei.c > > +++ b/fs/namei.c > > @@ -2849,6 +2849,13 @@ static int may_open(const struct path *path, int acc_mode, int flag) > > break; > > } > > > > + if (unlikely(mask & MAY_OPENEXEC)) { > > + if (sysctl_omayexec_enforce & OMAYEXEC_ENFORCE_MOUNT && > > + path_noexec(path)) > > + return -EACCES; > > + if (sysctl_omayexec_enforce & OMAYEXEC_ENFORCE_FILE) > > + acc_mode |= MAY_EXEC; > > + } > > error = inode_permission(inode, MAY_OPEN | acc_mode); > > if (error) > > return error; > > > > FYI, I've confirmed this now. Effectively with patch 2 dropped, patch 3 > reduced to this plus the Kconfig and sysctl changes, the self tests > pass. > > I think this makes things much cleaner and correct. And a summary of that would be right for the 0/n patch email. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)