From patchwork Mon Mar 14 14:55:17 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Gruenbacher X-Patchwork-Id: 8580101 Return-Path: X-Original-To: patchwork-cifs-client@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 143B39F54C for ; Mon, 14 Mar 2016 14:59:02 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 0398A201EF for ; Mon, 14 Mar 2016 14:59:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C9849202E5 for ; Mon, 14 Mar 2016 14:58:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965581AbcCNO4q (ORCPT ); Mon, 14 Mar 2016 10:56:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44922 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965271AbcCNO4o (ORCPT ); Mon, 14 Mar 2016 10:56:44 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (Postfix) with ESMTPS id 169E84D6A9; Mon, 14 Mar 2016 14:56:44 +0000 (UTC) Received: from nux.redhat.com (vpn1-5-74.ams2.redhat.com [10.36.5.74]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u2EEtN9v021293; Mon, 14 Mar 2016 10:56:40 -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 v19 18/23] richacl: Automatic Inheritance Date: Mon, 14 Mar 2016 15:55:17 +0100 Message-Id: <1457967322-14886-19-git-send-email-agruenba@redhat.com> In-Reply-To: <1457967322-14886-1-git-send-email-agruenba@redhat.com> References: <1457967322-14886-1-git-send-email-agruenba@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, 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 Automatic Inheritance (AI) allows changes to the acl of a directory to propagate down to children. This is mostly implemented in user space: when a process changes the permissions of a directory and Automatic Inheritance is enabled for that directory, the process must propagate those changes to all children, recursively. The kernel enables this by keeping track of which permissions have been inherited at create time. In addition, it makes sure that permission propagation is turned off when the permissions are set explicitly (for example, upon create or chmod). Automatic Inheritance works as follows: - When the RICHACL_AUTO_INHERIT flag in the acl of a file or directory is not set, the file or directory is not affected by AI. - When the RICHACL_AUTO_INHERIT flag in the acl of a directory is set and a file or subdirectory is created in that directory, the inherited acl will have the RICHACL_AUTO_INHERIT flag set, and all inherited aces will have the RICHACE_INHERITED_ACE flag set. This allows user space to distinguish between aces which have been inherited and aces which have been explicitly added. - When the RICHACL_PROTECTED acl flag in the acl of a file or directory is set, AI will not modify the acl. This does not affect propagation of permissions from the file to its children (if the file is a directory). Linux does not have a way of creating files or directories without setting the file permission bits, so all files created inside a directory with RICHACL_AUTO_INHERIT set will have the RICHACL_PROTECTED flag set. This effectively disables Automatic Inheritance. Protocols which support creating files without specifying permissions can explicitly clear the RICHACL_PROTECTED flag after creating a file and reset the file masks to "undo" applying the create mode; see richacl_compute_max_masks(). They should set the RICHACL_DEFAULTED flag. (A mechanism that would allow to indicate to the kernel to ignore the create mode in the first place when there are inherited permissions would be nice to have.) Signed-off-by: Andreas Gruenbacher --- fs/richacl_base.c | 13 ++++++++++++- fs/richacl_inode.c | 7 +++++++ include/linux/richacl.h | 12 ++++++++++++ include/uapi/linux/richacl.h | 11 ++++++++++- 4 files changed, 41 insertions(+), 2 deletions(-) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index b66d940..724b5e0 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -364,7 +364,8 @@ __richacl_chmod(struct richacl *acl, umode_t mode) acl->a_group_mask == group_mask && acl->a_other_mask == other_mask && (acl->a_flags & RICHACL_MASKED) && - (acl->a_flags & RICHACL_WRITE_THROUGH)) + (acl->a_flags & RICHACL_WRITE_THROUGH) && + (!richacl_is_auto_inherit(acl) || richacl_is_protected(acl))) return acl; clone = richacl_clone(acl, GFP_KERNEL); @@ -376,6 +377,8 @@ __richacl_chmod(struct richacl *acl, umode_t mode) clone->a_owner_mask = owner_mask; clone->a_group_mask = group_mask; clone->a_other_mask = other_mask; + if (richacl_is_auto_inherit(clone)) + clone->a_flags |= RICHACL_PROTECTED; return clone; } @@ -562,6 +565,14 @@ richacl_inherit(const struct richacl *dir_acl, int isdir) ace++; } } + if (richacl_is_auto_inherit(dir_acl)) { + acl->a_flags = RICHACL_AUTO_INHERIT; + richacl_for_each_entry(ace, acl) + ace->e_flags |= RICHACE_INHERITED_ACE; + } else { + richacl_for_each_entry(ace, acl) + ace->e_flags &= ~RICHACE_INHERITED_ACE; + } return acl; } diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c index ec3d2c8..99a1ab6 100644 --- a/fs/richacl_inode.c +++ b/fs/richacl_inode.c @@ -279,6 +279,13 @@ richacl_inherit_inode(const struct richacl *dir_acl, umode_t *mode_p) richacl_put(acl); acl = NULL; } else { + /* + * We need to set RICHACL_PROTECTED because we are + * doing an implicit chmod + */ + if (richacl_is_auto_inherit(acl)) + acl->a_flags |= RICHACL_PROTECTED; + richacl_compute_max_masks(acl); /* * Ensure that the acl will not grant any permissions diff --git a/include/linux/richacl.h b/include/linux/richacl.h index c8fae91a..c524a4b 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -76,6 +76,18 @@ extern void set_cached_richacl(struct inode *, struct richacl *); extern void forget_cached_richacl(struct inode *); extern struct richacl *get_richacl(struct inode *); +static inline int +richacl_is_auto_inherit(const struct richacl *acl) +{ + return acl->a_flags & RICHACL_AUTO_INHERIT; +} + +static inline int +richacl_is_protected(const struct richacl *acl) +{ + return acl->a_flags & RICHACL_PROTECTED; +} + /** * richace_is_owner - check if @ace is an OWNER@ entry */ diff --git a/include/uapi/linux/richacl.h b/include/uapi/linux/richacl.h index 1ed48ac..8849a53 100644 --- a/include/uapi/linux/richacl.h +++ b/include/uapi/linux/richacl.h @@ -18,6 +18,9 @@ #define __UAPI_RICHACL_H /* a_flags values */ +#define RICHACL_AUTO_INHERIT 0x01 +#define RICHACL_PROTECTED 0x02 +#define RICHACL_DEFAULTED 0x04 #define RICHACL_WRITE_THROUGH 0x40 #define RICHACL_MASKED 0x80 @@ -31,6 +34,7 @@ #define RICHACE_NO_PROPAGATE_INHERIT_ACE 0x0004 #define RICHACE_INHERIT_ONLY_ACE 0x0008 #define RICHACE_IDENTIFIER_GROUP 0x0040 +#define RICHACE_INHERITED_ACE 0x0080 #define RICHACE_SPECIAL_WHO 0x4000 /* e_mask bitflags */ @@ -60,6 +64,9 @@ #define RICHACE_EVERYONE_SPECIAL_ID 2 #define RICHACL_VALID_FLAGS ( \ + RICHACL_AUTO_INHERIT | \ + RICHACL_PROTECTED | \ + RICHACL_DEFAULTED | \ RICHACL_WRITE_THROUGH | \ RICHACL_MASKED ) @@ -69,13 +76,15 @@ RICHACE_NO_PROPAGATE_INHERIT_ACE | \ RICHACE_INHERIT_ONLY_ACE | \ RICHACE_IDENTIFIER_GROUP | \ + RICHACE_INHERITED_ACE | \ RICHACE_SPECIAL_WHO ) #define RICHACE_INHERITANCE_FLAGS ( \ RICHACE_FILE_INHERIT_ACE | \ RICHACE_DIRECTORY_INHERIT_ACE | \ RICHACE_NO_PROPAGATE_INHERIT_ACE | \ - RICHACE_INHERIT_ONLY_ACE ) + RICHACE_INHERIT_ONLY_ACE | \ + RICHACE_INHERITED_ACE ) /* Valid RICHACE_* flags for directories and non-directories */ #define RICHACE_VALID_MASK ( \