From patchwork Mon Sep 5 17:25:42 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Aneesh Kumar K.V" X-Patchwork-Id: 1125102 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p85HSSoF027832 for ; Mon, 5 Sep 2011 17:28:28 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752229Ab1IER1k (ORCPT ); Mon, 5 Sep 2011 13:27:40 -0400 Received: from e28smtp07.in.ibm.com ([122.248.162.7]:50258 "EHLO e28smtp07.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752167Ab1IER1f (ORCPT ); Mon, 5 Sep 2011 13:27:35 -0400 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by e28smtp07.in.ibm.com (8.14.4/8.13.1) with ESMTP id p85HRWjR000969; Mon, 5 Sep 2011 22:57:32 +0530 Received: from d28av03.in.ibm.com (d28av03.in.ibm.com [9.184.220.65]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p85HRV4k3289260; Mon, 5 Sep 2011 22:57:31 +0530 Received: from d28av03.in.ibm.com (loopback [127.0.0.1]) by d28av03.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p85HRVgI021880; Tue, 6 Sep 2011 03:27:31 +1000 Received: from skywalker.ibm.com ([9.126.239.225]) by d28av03.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id p85HR6rb021311; Tue, 6 Sep 2011 03:27:30 +1000 From: "Aneesh Kumar K.V" To: agruen@kernel.org, bfields@fieldses.org, akpm@linux-foundation.org, dhowells@redhat.com Cc: aneesh.kumar@linux.vnet.ibm.com, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH -V6 20/26] richacl: Automatic Inheritance Date: Mon, 5 Sep 2011 22:55:42 +0530 Message-Id: <1315243548-18664-21-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1315243548-18664-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1315243548-18664-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Mon, 05 Sep 2011 17:28:28 +0000 (UTC) From: Andreas Gruenbacher Automatic Inheritance (AI) allows changes to the acl of a directory to recursively propagate down to files and directories in the directory. To implement this, the kernel keeps track of which permissions have been inherited, and makes sure that permission propagation is turned off when the file permission bits of a file are changed (upon create or chmod). The actual permission propagation is implemented in user space. AI works as follows: - When the ACL4_AUTO_INHERIT flag in the acl of a file is cleared, the file is not affected by AI. - When the ACL4_AUTO_INHERIT flag in the acl of a directory is set and a file or subdirectory is created in that directory, files created in the directory will have the ACL4_AUTO_INHERIT flag set, and all inherited aces will have the ACE4_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 ACL4_PROTECTED acl flag in the acl of a file is set, AI will not modify the acl of the file. 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 without setting the file permission bits, so all files created inside a directory with ACL4_AUTO_INHERIT set will also have the ACL4_PROTECTED flag set. This effectively disables AI. Protocols which support creating files without specifying permissions can explicitly clear the ACL4_PROTECTED flag after creating a file (and reset the file masks to "undo" applying the create mode; see richacl_compute_max_masks()). This is a workaround; a per-create or per-process flag indicating to ignore the create mode when AI is in effect would fix this problem. Signed-off-by: Andreas Gruenbacher Signed-off-by: Aneesh Kumar K.V --- fs/richacl_base.c | 10 +++++++++- fs/richacl_inode.c | 7 ++++++- include/linux/richacl.h | 25 +++++++++++++++++++++++-- 3 files changed, 38 insertions(+), 4 deletions(-) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index 9d61c34..2cdc244 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -377,7 +377,8 @@ richacl_chmod(struct richacl *acl, mode_t mode) if (acl->a_owner_mask == owner_mask && acl->a_group_mask == group_mask && acl->a_other_mask == other_mask && - (acl->a_flags & ACL4_MASKED)) + (acl->a_flags & ACL4_MASKED) && + (!richacl_is_auto_inherit(acl) || richacl_is_protected(acl))) return acl; clone = richacl_clone(acl); @@ -389,6 +390,8 @@ richacl_chmod(struct richacl *acl, mode_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 |= ACL4_PROTECTED; return clone; } @@ -558,6 +561,11 @@ richacl_inherit(const struct richacl *dir_acl, int isdir) ace++; } } + if (richacl_is_auto_inherit(dir_acl)) { + acl->a_flags = ACL4_AUTO_INHERIT; + richacl_for_each_entry(ace, acl) + ace->e_flags |= ACE4_INHERITED_ACE; + } return acl; } diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c index a8d2beb..be6c3eb 100644 --- a/fs/richacl_inode.c +++ b/fs/richacl_inode.c @@ -37,9 +37,14 @@ richacl_inherit_inode(const struct richacl *dir_acl, struct inode *inode) acl = richacl_inherit(dir_acl, S_ISDIR(inode->i_mode)); if (acl) { + /* + * We need to set ACL4_PROTECTED because we are + * doing an implicit chmod + */ + if (richacl_is_auto_inherit(acl)) + acl->a_flags |= ACL4_PROTECTED; richacl_compute_max_masks(acl); - /* * Ensure that the acl will not grant any permissions beyond * the create mode. diff --git a/include/linux/richacl.h b/include/linux/richacl.h index d18c4a6..ca07209 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -47,10 +47,16 @@ struct richacl { _ace != _acl->a_entries - 1; \ _ace--) +/* a_flags values */ +#define ACL4_AUTO_INHERIT 0x01 +#define ACL4_PROTECTED 0x02 +/* #define ACL4_DEFAULTED 0x04 */ /* Flag values defined by rich-acl */ #define ACL4_MASKED 0x80 #define ACL4_VALID_FLAGS ( \ + ACL4_AUTO_INHERIT | \ + ACL4_PROTECTED | \ ACL4_MASKED) /* e_type values */ @@ -67,6 +73,7 @@ struct richacl { /*#define ACE4_SUCCESSFUL_ACCESS_ACE_FLAG 0x0010*/ /*#define ACE4_FAILED_ACCESS_ACE_FLAG 0x0020*/ #define ACE4_IDENTIFIER_GROUP 0x0040 +#define ACE4_INHERITED_ACE 0x0080 /* in-memory representation only */ #define ACE4_SPECIAL_WHO 0x4000 @@ -75,7 +82,8 @@ struct richacl { ACE4_DIRECTORY_INHERIT_ACE | \ ACE4_NO_PROPAGATE_INHERIT_ACE | \ ACE4_INHERIT_ONLY_ACE | \ - ACE4_IDENTIFIER_GROUP) + ACE4_IDENTIFIER_GROUP | \ + ACE4_INHERITED_ACE) /* e_mask bitflags */ #define ACE4_READ_DATA 0x00000001 @@ -181,6 +189,18 @@ richacl_put(struct richacl *acl) kfree(acl); } +static inline int +richacl_is_auto_inherit(const struct richacl *acl) +{ + return acl->a_flags & ACL4_AUTO_INHERIT; +} + +static inline int +richacl_is_protected(const struct richacl *acl) +{ + return acl->a_flags & ACL4_PROTECTED; +} + /* * Special e_who identifiers: we use these pointer values in comparisons * instead of doing a strcmp. @@ -259,7 +279,8 @@ richace_clear_inheritance_flags(struct richace *ace) ace->e_flags &= ~(ACE4_FILE_INHERIT_ACE | ACE4_DIRECTORY_INHERIT_ACE | ACE4_NO_PROPAGATE_INHERIT_ACE | - ACE4_INHERIT_ONLY_ACE); + ACE4_INHERIT_ONLY_ACE | + ACE4_INHERITED_ACE); } /**