From patchwork Wed Sep 28 23:29:33 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Gruenbacher X-Patchwork-Id: 9355289 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 4C02A6077B for ; Wed, 28 Sep 2016 23:35:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3ED5B29651 for ; Wed, 28 Sep 2016 23:35:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 322C2296EE; Wed, 28 Sep 2016 23:35:05 +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 AF9FB29651 for ; Wed, 28 Sep 2016 23:35:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754963AbcI1XeA (ORCPT ); Wed, 28 Sep 2016 19:34:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43112 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754398AbcI1XbA (ORCPT ); Wed, 28 Sep 2016 19:31:00 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (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 4A3F5BE28E; Wed, 28 Sep 2016 23:31:00 +0000 (UTC) Received: from nux.redhat.com (vpn1-4-153.ams2.redhat.com [10.36.4.153]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u8SNTfN3015711; Wed, 28 Sep 2016 19:30:55 -0400 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, xfs@oss.sgi.com, 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 Subject: [PATCH v26 14/21] richacl: Create-time inheritance Date: Thu, 29 Sep 2016 01:29:33 +0200 Message-Id: <1475105380-22837-15-git-send-email-agruenba@redhat.com> In-Reply-To: <1475105380-22837-1-git-send-email-agruenba@redhat.com> References: <1475105380-22837-1-git-send-email-agruenba@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Wed, 28 Sep 2016 23:31:00 +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 When a new file is created, it can inherit an acl from its parent directory; this is similar to how default acls work in POSIX ACLs. As with POSIX ACLs, if a file inherits an acl from its parent directory, the intersection between the create mode and the permissions granted by the inherited acl determines the file masks and file permission bits, and the umask is ignored. Signed-off-by: Andreas Gruenbacher Reviewed-by: Jeff Layton --- fs/richacl.c | 151 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/richacl.h | 2 + 2 files changed, 153 insertions(+) diff --git a/fs/richacl.c b/fs/richacl.c index 1022983..8051181 100644 --- a/fs/richacl.c +++ b/fs/richacl.c @@ -716,3 +716,154 @@ richacl_equiv_mode(const struct richacl *acl, umode_t *mode_p) return 0; } EXPORT_SYMBOL_GPL(richacl_equiv_mode); + +static inline bool +ace_inherits_to_directory(const struct richace *ace) +{ + if (ace->e_flags & RICHACE_DIRECTORY_INHERIT_ACE) + return true; + if ((ace->e_flags & RICHACE_FILE_INHERIT_ACE) && + !(ace->e_flags & RICHACE_NO_PROPAGATE_INHERIT_ACE)) + return true; + return false; +} + +/** + * richacl_inherit - compute the inherited acl of a new file + * @dir_acl: acl of the containing directory + * @isdir: inherit by a directory or non-directory? + * + * A directory can have acl entries which files and/or directories created + * inside the directory will inherit. This function computes the acl for such + * a new file. If there is no inheritable acl, it will return %NULL. + */ +struct richacl * +richacl_inherit(const struct richacl *dir_acl, int isdir) +{ + const struct richace *dir_ace; + struct richacl *acl = NULL; + struct richace *ace; + int count = 0; + + if (isdir) { + richacl_for_each_entry(dir_ace, dir_acl) { + if (!ace_inherits_to_directory(dir_ace)) + continue; + count++; + } + if (!count) + return NULL; + acl = richacl_alloc(count, GFP_KERNEL); + if (!acl) + return ERR_PTR(-ENOMEM); + ace = acl->a_entries; + richacl_for_each_entry(dir_ace, dir_acl) { + if (!ace_inherits_to_directory(dir_ace)) + continue; + richace_copy(ace, dir_ace); + if (dir_ace->e_flags & RICHACE_NO_PROPAGATE_INHERIT_ACE) + ace->e_flags &= ~RICHACE_INHERITANCE_FLAGS; + else if (dir_ace->e_flags & RICHACE_DIRECTORY_INHERIT_ACE) + ace->e_flags &= ~RICHACE_INHERIT_ONLY_ACE; + else + ace->e_flags |= RICHACE_INHERIT_ONLY_ACE; + ace++; + } + } else { + richacl_for_each_entry(dir_ace, dir_acl) { + if (!(dir_ace->e_flags & RICHACE_FILE_INHERIT_ACE)) + continue; + count++; + } + if (!count) + return NULL; + acl = richacl_alloc(count, GFP_KERNEL); + if (!acl) + return ERR_PTR(-ENOMEM); + ace = acl->a_entries; + richacl_for_each_entry(dir_ace, dir_acl) { + if (!(dir_ace->e_flags & RICHACE_FILE_INHERIT_ACE)) + continue; + richace_copy(ace, dir_ace); + ace->e_flags &= ~RICHACE_INHERITANCE_FLAGS; + /* + * RICHACE_DELETE_CHILD is meaningless for + * non-directories, so clear it. + */ + ace->e_mask &= ~RICHACE_DELETE_CHILD; + ace++; + } + } + + return acl; +} + +/* + * richacl_inherit_inode - compute inherited acl and file mode + * @dir_acl: acl of the containing directory + * @mode_p: mode of the new inode + * + * The file permission bits in @mode_p must be set to the create mode by the + * caller. + * + * If there is an inheritable acl, the maximum permissions that the acl grants + * are computed and the file masks of the new acl are set accordingly. + */ +static struct richacl * +richacl_inherit_inode(const struct richacl *dir_acl, umode_t *mode_p) +{ + struct richacl *acl; + umode_t mode = *mode_p; + + acl = richacl_inherit(dir_acl, S_ISDIR(mode)); + if (acl) { + if (richacl_equiv_mode(acl, &mode) == 0) { + *mode_p &= mode; + richacl_put(acl); + acl = NULL; + } else { + richacl_compute_max_masks(acl); + /* + * Ensure that the acl will not grant any permissions + * beyond the create mode. + */ + acl->a_flags |= RICHACL_MASKED; + acl->a_owner_mask &= + richacl_mode_to_mask(mode >> 6); + acl->a_group_mask &= + richacl_mode_to_mask(mode >> 3); + acl->a_other_mask &= + richacl_mode_to_mask(mode); + } + } else + *mode_p &= ~current_umask(); + + return acl; +} + +/** + * richacl_create - filesystem create helper + * @mode_p: mode of the new inode + * @dir: containing directory + * + * Compute the inherited acl for a new inode. If there is no acl to inherit, + * apply the umask. Use when creating a new inode on a richacl enabled file + * system. + */ +struct richacl *richacl_create(umode_t *mode_p, struct inode *dir) +{ + struct richacl *dir_acl, *acl = NULL; + + if (S_ISLNK(*mode_p)) + return NULL; + dir_acl = get_richacl(dir); + if (dir_acl) { + if (IS_ERR(dir_acl)) + return dir_acl; + acl = richacl_inherit_inode(dir_acl, mode_p); + richacl_put(dir_acl); + } else + *mode_p &= ~current_umask(); + return acl; +} +EXPORT_SYMBOL_GPL(richacl_create); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index a865f37..6354ef0 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -191,5 +191,7 @@ extern int richacl_permission(struct inode *, const struct richacl *, int); extern void richacl_compute_max_masks(struct richacl *); extern int richacl_chmod(struct inode *, umode_t); extern int richacl_equiv_mode(const struct richacl *, umode_t *); +extern struct richacl *richacl_inherit(const struct richacl *, int); +extern struct richacl *richacl_create(umode_t *, struct inode *); #endif /* __RICHACL_H */