From patchwork Wed Feb 23 13:52:02 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: 84150 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 8D0ADB70D9 for ; Thu, 24 Feb 2011 00:56:13 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932279Ab1BWNzr (ORCPT ); Wed, 23 Feb 2011 08:55:47 -0500 Received: from e28smtp05.in.ibm.com ([122.248.162.5]:57706 "EHLO e28smtp05.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932150Ab1BWNzp (ORCPT ); Wed, 23 Feb 2011 08:55:45 -0500 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by e28smtp05.in.ibm.com (8.14.4/8.13.1) with ESMTP id p1NDtV9p011683; Wed, 23 Feb 2011 19:25:31 +0530 Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p1NDtTfa3567760; Wed, 23 Feb 2011 19:25:31 +0530 Received: from d28av05.in.ibm.com (loopback [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p1NDreHT019710; Thu, 24 Feb 2011 00:53:43 +1100 Received: from skywalker.ibm.com ([9.77.68.27]) by d28av05.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id p1NDqS28014791; Thu, 24 Feb 2011 00:53:38 +1100 From: "Aneesh Kumar K.V" To: sfrench@us.ibm.com, agruen@linbit.com, dilger.kernel@dilger.ca, sandeen@redhat.com, tytso@mit.edu, bfields@fieldses.org, jlayton@redhat.com Cc: aneesh.kumar@linux.vnet.ibm.com, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, Andreas Gruenbacher Subject: [PATCH -V5 15/24] richacl: Update the file masks in chmod() Date: Wed, 23 Feb 2011 19:22:02 +0530 Message-Id: <1298469131-16555-16-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1298469131-16555-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1298469131-16555-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org From: Andreas Gruenbacher Doing a chmod() sets the file mode, which includes the file permission bits. When a file has a richacl, the permissions that the richacl grants need to be limited to what the new file permission bits allow. This is done by setting the file masks in the richacl to what the file permission bits map to. The richacl access check algorithm takes the file masks into account, which ensures that the richacl cannot grant too many permissions. It is possible to explicitly add permissions to the file masks which go beyond what the file permission bits can grant (like the ACE4_WRITE_ACL permission). The POSIX.1 standard calls this an alternate file access control mechanism. A subsequent chmod() would ensure that those permissions are disabled again. Signed-off-by: Andreas Gruenbacher Signed-off-by: Aneesh Kumar K.V --- fs/richacl_base.c | 40 ++++++++++++++++++++++++++++++++++++++++ include/linux/richacl.h | 1 + 2 files changed, 41 insertions(+), 0 deletions(-) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index 69ddb00..b59c75c 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -353,3 +353,43 @@ restart: acl->a_flags &= ~ACL4_MASKED; } EXPORT_SYMBOL_GPL(richacl_compute_max_masks); + +/** + * richacl_chmod - update the file masks to reflect the new mode + * @mode: new file permission bits + * + * Return a copy of @acl where the file masks have been replaced by the file + * masks corresponding to the file permission bits in @mode, or returns @acl + * itself if the file masks are already up to date. Takes over a reference + * to @acl. + */ +struct richacl * +richacl_chmod(struct richacl *acl, mode_t mode) +{ + unsigned int owner_mask, group_mask, other_mask; + struct richacl *clone; + + owner_mask = richacl_mode_to_mask(mode >> 6) | + ACE4_POSIX_OWNER_ALLOWED; + group_mask = richacl_mode_to_mask(mode >> 3); + other_mask = richacl_mode_to_mask(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)) + return acl; + + clone = richacl_clone(acl); + richacl_put(acl); + if (!clone) + return ERR_PTR(-ENOMEM); + + clone->a_flags |= ACL4_MASKED; + clone->a_owner_mask = owner_mask; + clone->a_group_mask = group_mask; + clone->a_other_mask = other_mask; + + return clone; +} +EXPORT_SYMBOL_GPL(richacl_chmod); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index f491e59..3aa165b 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -288,5 +288,6 @@ extern int richacl_masks_to_mode(const struct richacl *); extern unsigned int richacl_mode_to_mask(mode_t); extern unsigned int richacl_want_to_mask(int); extern void richacl_compute_max_masks(struct richacl *); +extern struct richacl *richacl_chmod(struct richacl *, mode_t); #endif /* __RICHACL_H */