From patchwork Mon Feb 13 15:32:34 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Gruenbacher X-Patchwork-Id: 9570023 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 6629B6045D for ; Mon, 13 Feb 2017 15:37:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5BF2E28173 for ; Mon, 13 Feb 2017 15:37:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 50FE928355; Mon, 13 Feb 2017 15:37:48 +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=unavailable 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 ECF97281D2 for ; Mon, 13 Feb 2017 15:37:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753610AbdBMPeL (ORCPT ); Mon, 13 Feb 2017 10:34:11 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45288 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753604AbdBMPeI (ORCPT ); Mon, 13 Feb 2017 10:34:08 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5615F61D2B; Mon, 13 Feb 2017 15:33:54 +0000 (UTC) Received: from nux.redhat.com (ovpn-117-141.ams2.redhat.com [10.36.117.141]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v1DFWd4c006129; Mon, 13 Feb 2017 10:33:50 -0500 From: Andreas Gruenbacher To: Alexander Viro Cc: Andreas Gruenbacher , Christoph Hellwig , "Theodore Ts'o" , Andreas Dilger , "J. Bruce Fields" , Jeff Layton , Trond Myklebust , Anna Schumaker , Dave Chinner , linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-api@vger.kernel.org, Jeff Layton Subject: [PATCH v28 18/21] vfs: Add richacl permission checking Date: Mon, 13 Feb 2017 16:32:34 +0100 Message-Id: <1486999957-2381-19-git-send-email-agruenba@redhat.com> In-Reply-To: <1486999957-2381-1-git-send-email-agruenba@redhat.com> References: <1486999957-2381-1-git-send-email-agruenba@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Mon, 13 Feb 2017 15:33:54 +0000 (UTC) Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Hook the richacl permission checking function into the vfs. Signed-off-by: Andreas Gruenbacher Cc: Jeff Layton --- fs/namei.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-- fs/richacl.c | 4 ++-- 2 files changed, 70 insertions(+), 4 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 4b53754..7ea153b 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #include #include @@ -257,7 +258,43 @@ void putname(struct filename *name) __putname(name); } -static int check_acl(struct inode *inode, int mask) +static int check_richacl(struct inode *inode, int mask) +{ +#ifdef CONFIG_FS_RICHACL + if (mask & MAY_NOT_BLOCK) { + struct base_acl *base_acl; + + base_acl = rcu_dereference(inode->i_acl); + if (!base_acl) + goto no_acl; + /* no ->get_richacl() calls in RCU mode... */ + if (is_uncached_acl(base_acl)) + return -ECHILD; + return richacl_permission(inode, richacl(base_acl), + mask & ~MAY_NOT_BLOCK); + } else { + struct richacl *acl; + + acl = get_richacl(inode); + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (acl) { + int error = richacl_permission(inode, acl, mask); + richacl_put(acl); + return error; + } + } +no_acl: +#endif + if (mask & (MAY_DELETE_SELF | MAY_TAKE_OWNERSHIP | + MAY_CHMOD | MAY_SET_TIMES)) { + /* File permission bits cannot grant this. */ + return -EACCES; + } + return -EAGAIN; +} + +static int check_posix_acl(struct inode *inode, int mask) { #ifdef CONFIG_FS_POSIX_ACL if (mask & MAY_NOT_BLOCK) { @@ -295,11 +332,40 @@ static int acl_permission_check(struct inode *inode, int mask) { unsigned int mode = inode->i_mode; + /* + * With POSIX ACLs, the (mode & S_IRWXU) bits exactly match the owner + * permissions, and we can skip checking posix acls for the owner. + * With richacls, the owner may be granted fewer permissions than the + * mode bits seem to suggest (for example, append but not write), and + * we always need to check the richacl. + */ + + if (IS_RICHACL(inode)) { + int error; + + /* + * The combination of MAY_DELETE_CHILD and MAY_DELETE_SELF + * indicates that that we want to check for delete permission + * in a directory assuming that we have MAY_DELETE_SELF access + * on the victim. We don't require MAY_DELETE_CHILD permission + * on the directory, but we do require LSM permission, the + * immutability checks, etc. + */ + if ((mask & MAY_DELETE_CHILD) && (mask & MAY_DELETE_SELF)) { + mask &= ~(MAY_DELETE_CHILD | MAY_DELETE_SELF); + if (!(mask & (MAY_CREATE_FILE | MAY_CREATE_DIR))) + mask &= ~MAY_WRITE; + } + + error = check_richacl(inode, mask); + if (error != -EAGAIN) + return error; + } if (likely(uid_eq(current_fsuid(), inode->i_uid))) mode >>= 6; else { if (IS_POSIXACL(inode) && (mode & S_IRWXG)) { - int error = check_acl(inode, mask); + int error = check_posix_acl(inode, mask); if (error != -EAGAIN) return error; } diff --git a/fs/richacl.c b/fs/richacl.c index 1945691..416d57c 100644 --- a/fs/richacl.c +++ b/fs/richacl.c @@ -293,8 +293,8 @@ richacl_permission(struct inode *inode, const struct richacl *acl, } else { /* * When the acl is not masked, there is no need to determine if - * the process is in the group class and we can break out - * earlier of the loop below. + * the process is in the group class and we can earlier break + * out of the loop below. */ in_owner_or_group_class = 1; }