From patchwork Tue Aug 4 11:53:12 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Andreas_Gr=C3=BCnbacher?= X-Patchwork-Id: 6937921 Return-Path: X-Original-To: patchwork-cifs-client@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 4DFBFC05AC for ; Tue, 4 Aug 2015 12:08:52 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 3D889203E1 for ; Tue, 4 Aug 2015 12:08:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C77812047B for ; Tue, 4 Aug 2015 12:08:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933228AbbHDMI3 (ORCPT ); Tue, 4 Aug 2015 08:08:29 -0400 Received: from mail-wi0-f171.google.com ([209.85.212.171]:38682 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933577AbbHDLy6 (ORCPT ); Tue, 4 Aug 2015 07:54:58 -0400 Received: by wibxm9 with SMTP id xm9so20337085wib.1; Tue, 04 Aug 2015 04:54:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=Qx2ppeY7oTm56zJ5k2pJtR0v3EgWmrT1niAnM3Zfqh8=; b=KBHI9hLHmnBj3RYuiyu9/lykw3fCuho07He2IhGDGGkKQh/EJDNdyOUZomSCRmr1x9 SU4VKbLCtBCgdFGZKb2Jxa7SFavc88XahbkJtUaisCatPlSRwSlTToOz1nRJNDUkN8Ts zEDxosmxdZ3kB2nBQykPMOhdzy7Nc0BZowegw9uyl5R8zfgidGNGOENlauFs58vmFWTG E9c4wtvcm3aEBRDyQg+TCOFfvu+A3o0xW5NO3OQ2OZoKxpbfR7FWti9sYt+h9RYNjPpZ J+68q7IkcXtgG6e3PqwwGdDjS45dCsF2tT82NjlU+212amptoXisEhuP7ZKqhE1bar8l z12g== X-Received: by 10.180.188.3 with SMTP id fw3mr6122231wic.5.1438689296228; Tue, 04 Aug 2015 04:54:56 -0700 (PDT) Received: from schleppi.home.com (p54980F84.dip0.t-ipconnect.de. [84.152.15.132]) by smtp.gmail.com with ESMTPSA id u7sm2018458wif.3.2015.08.04.04.54.54 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 04 Aug 2015 04:54:55 -0700 (PDT) From: Andreas Gruenbacher X-Google-Original-From: Andreas Gruenbacher To: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-api@vger.kernel.org, linux-cifs@vger.kernel.org, linux-security-module@vger.kernel.org, Andreas Gruenbacher Subject: [RFC v6 14/40] richacl: Create-time inheritance Date: Tue, 4 Aug 2015 13:53:12 +0200 Message-Id: <1438689218-6921-15-git-send-email-agruenba@redhat.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1438689218-6921-1-git-send-email-agruenba@redhat.com> References: <1438689218-6921-1-git-send-email-agruenba@redhat.com> Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, SUSPICIOUS_RECIPS, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.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 (draft) 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 --- fs/richacl_base.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++ fs/richacl_inode.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/richacl.h | 2 ++ 3 files changed, 136 insertions(+) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index 3e9ef9e..a8e21e5 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -482,3 +482,72 @@ richacl_equiv_mode(const struct richacl *acl, mode_t *mode_p) return 0; } EXPORT_SYMBOL_GPL(richacl_equiv_mode); + +/** + * 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 (!richace_is_inheritable(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 (!richace_is_inheritable(dir_ace)) + continue; + richace_copy(ace, dir_ace); + if (dir_ace->e_flags & RICHACE_NO_PROPAGATE_INHERIT_ACE) + richace_clear_inheritance_flags(ace); + if ((dir_ace->e_flags & RICHACE_FILE_INHERIT_ACE) && + !(dir_ace->e_flags & RICHACE_DIRECTORY_INHERIT_ACE)) + 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); + richace_clear_inheritance_flags(ace); + /* + * RICHACE_DELETE_CHILD is meaningless for + * non-directories, so clear it. + */ + ace->e_mask &= ~RICHACE_DELETE_CHILD; + ace++; + } + } + + return acl; +} diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c index 48ba7d9..7081c3e 100644 --- a/fs/richacl_inode.c +++ b/fs/richacl_inode.c @@ -219,3 +219,68 @@ out: return denied ? -EACCES : 0; } EXPORT_SYMBOL_GPL(richacl_permission); + +/** + * richacl_inherit_inode - compute inherited acl and file mode + * @dir_acl: acl of the containing directory + * @inode: inode of the new file (create mode in i_mode) + * + * The file permission bits in inode->i_mode must be set to the create mode by + * the caller. + * + * If there is an inheritable acl, the maximum permissions that the acl grants + * will be computed and permissions not granted by the acl will be removed from + * inode->i_mode. If there is no inheritable acl, the umask will be applied + * instead. + */ +static struct richacl * +richacl_inherit_inode(const struct richacl *dir_acl, struct inode *inode) +{ + struct richacl *acl; + mode_t mask; + + acl = richacl_inherit(dir_acl, S_ISDIR(inode->i_mode)); + if (acl) { + mask = inode->i_mode; + if (richacl_equiv_mode(acl, &mask) == 0) { + richacl_put(acl); + acl = NULL; + } else { + richacl_compute_max_masks(acl, inode->i_uid); + /* + * 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(inode->i_mode >> 6); + acl->a_group_mask &= + richacl_mode_to_mask(inode->i_mode >> 3); + acl->a_other_mask &= + richacl_mode_to_mask(inode->i_mode); + mask = ~S_IRWXUGO | richacl_masks_to_mode(acl); + } + } else + mask = ~current_umask(); + + inode->i_mode &= mask; + return acl; +} + +struct richacl *richacl_create(struct inode *inode, struct inode *dir) +{ + struct richacl *dir_acl, *acl = NULL; + + if (S_ISLNK(inode->i_mode)) + return NULL; + dir_acl = get_richacl(dir); + if (dir_acl) { + if (IS_ERR(dir_acl)) + return dir_acl; + acl = richacl_inherit_inode(dir_acl, inode); + richacl_put(dir_acl); + } else + inode->i_mode &= ~current_umask(); + return acl; +} +EXPORT_SYMBOL_GPL(richacl_create); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index 6a2ba34..4917d30 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -311,8 +311,10 @@ extern unsigned int richacl_want_to_mask(unsigned int); extern void richacl_compute_max_masks(struct richacl *, kuid_t); extern struct richacl *richacl_chmod(struct richacl *, mode_t); extern int richacl_equiv_mode(const struct richacl *, mode_t *); +extern struct richacl *richacl_inherit(const struct richacl *, int); /* richacl_inode.c */ extern int richacl_permission(struct inode *, const struct richacl *, int); +extern struct richacl *richacl_create(struct inode *, struct inode *); #endif /* __RICHACL_H */