From patchwork Wed Jun 24 21:57:03 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: 6670761 Return-Path: X-Original-To: patchwork-linux-fsdevel@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 C964DC05AC for ; Wed, 24 Jun 2015 22:04:43 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C6DBB20547 for ; Wed, 24 Jun 2015 22:04:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AA9642056E for ; Wed, 24 Jun 2015 22:04:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753825AbbFXWEc (ORCPT ); Wed, 24 Jun 2015 18:04:32 -0400 Received: from mail-wi0-f175.google.com ([209.85.212.175]:33734 "EHLO mail-wi0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752250AbbFXV5x (ORCPT ); Wed, 24 Jun 2015 17:57:53 -0400 Received: by wiwl6 with SMTP id l6so1148316wiw.0; Wed, 24 Jun 2015 14:57:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:subject:date:message-id:in-reply-to:references; bh=k1nTdEUkXyrrfj+unXlPretk18CF0nVLF3DRXtvfMRk=; b=YabgFpDx44y6II5pvJsnUHuzvp0stgcmboXhVNiKAe8cNDAV8ylOr3fQIV1SJH8Aki mYi1Vplg5qH5EkZtS5/ZAvuo/owqyEiLDnU1L+l8qc8QyJelkagaYHjFtOgR7kBXMKoV 1IgCcee9iEL9SkaRITFTD7XxcIL1/I+t0HhNF8KzkJfFZ9cZNAO3nlky75Nz3bpA9pvV xk5eNWO7CRu4NnWbtLkco/k2ANigCRcsZME5e0tc7FUJsiWTici1LjZS18787BY9cny0 YI5K9iNKMSeXLDhiTUQDFFv2nEifLtIgRubQQRshcE82KE+zsAxk0eWvy3vW6Br9j8bI xz3w== X-Received: by 10.180.96.196 with SMTP id du4mr8503190wib.77.1435183071485; Wed, 24 Jun 2015 14:57:51 -0700 (PDT) Received: from nuc.home.com (80-110-112-232.cgn.dynamic.surfer.at. [80.110.112.232]) by mx.google.com with ESMTPSA id lu5sm42559880wjb.9.2015.06.24.14.57.50 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Jun 2015 14:57:50 -0700 (PDT) From: Andreas Gruenbacher X-Google-Original-From: Andreas Gruenbacher To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-api@vger.kernel.org, samba-technical@lists.samba.org, linux-security-module@vger.kernel.org Subject: [RFC v4 14/31] richacl: Create-time inheritance Date: Wed, 24 Jun 2015 23:57:03 +0200 Message-Id: <1435183040-22726-15-git-send-email-agruenba@redhat.com> X-Mailer: git-send-email 2.4.2 In-Reply-To: <1435183040-22726-1-git-send-email-agruenba@redhat.com> References: <1435183040-22726-1-git-send-email-agruenba@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-5.7 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 | 62 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/richacl.h | 2 ++ 3 files changed, 133 insertions(+) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index 1ef3bf3..29d3197 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -460,3 +460,72 @@ 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; + memcpy(ace, dir_ace, sizeof(struct richace)); + 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; + memcpy(ace, dir_ace, sizeof(struct richace)); + 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 4b06ab3..f233872 100644 --- a/fs/richacl_inode.c +++ b/fs/richacl_inode.c @@ -193,3 +193,65 @@ 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 2357d6b..3fcefe3 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -308,8 +308,10 @@ 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 */