From patchwork Mon Oct 5 19:36:40 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Gruenbacher X-Patchwork-Id: 7331261 Return-Path: X-Original-To: patchwork-linux-nfs@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 1014B9F302 for ; Mon, 5 Oct 2015 20:07:46 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 26F2620615 for ; Mon, 5 Oct 2015 20:07:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 248D520603 for ; Mon, 5 Oct 2015 20:07:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752513AbbJETid (ORCPT ); Mon, 5 Oct 2015 15:38:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36151 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751300AbbJETia (ORCPT ); Mon, 5 Oct 2015 15:38:30 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (Postfix) with ESMTPS id 624BAC0B64CD; Mon, 5 Oct 2015 19:38:30 +0000 (UTC) Received: from nux.home.com (vpn1-7-226.ams2.redhat.com [10.36.7.226]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t95JbDHS018133; Mon, 5 Oct 2015 15:38:25 -0400 From: Andreas Gruenbacher To: Alexander Viro , "Theodore Ts'o" , Andreas Dilger , "J. Bruce Fields" , Jeff Layton , Trond Myklebust , Anna Schumaker , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-api@vger.kernel.org Subject: [PATCH v9 13/43] richacl: Update the file masks in chmod() Date: Mon, 5 Oct 2015 21:36:40 +0200 Message-Id: <1444073830-21854-14-git-send-email-agruenba@redhat.com> In-Reply-To: <1444073830-21854-1-git-send-email-agruenba@redhat.com> References: <1444073830-21854-1-git-send-email-agruenba@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_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 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 RICHACE_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 Reviewed-by: J. Bruce Fields --- fs/richacl_base.c | 41 +++++++++++++++++++++++++++++++++++++++++ fs/richacl_inode.c | 30 ++++++++++++++++++++++++++++++ include/linux/richacl.h | 2 ++ 3 files changed, 73 insertions(+) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index 0585295..d4480e5 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -339,3 +339,44 @@ restart: acl->a_flags &= ~(RICHACL_WRITE_THROUGH | RICHACL_MASKED); } EXPORT_SYMBOL_GPL(richacl_compute_max_masks); + +/** + * __richacl_chmod - update the file masks to reflect the new mode + * @mode: new file permission bits including the file type + * + * 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 x = S_ISDIR(mode) ? 0 : RICHACE_DELETE_CHILD; + unsigned int owner_mask, group_mask, other_mask; + struct richacl *clone; + + owner_mask = richacl_mode_to_mask(mode >> 6) & ~x; + group_mask = richacl_mode_to_mask(mode >> 3) & ~x; + other_mask = richacl_mode_to_mask(mode) & ~x; + + if (acl->a_owner_mask == owner_mask && + acl->a_group_mask == group_mask && + acl->a_other_mask == other_mask && + (acl->a_flags & RICHACL_MASKED) && + (acl->a_flags & RICHACL_WRITE_THROUGH)) + return acl; + + clone = richacl_clone(acl, GFP_KERNEL); + richacl_put(acl); + if (!clone) + return ERR_PTR(-ENOMEM); + + clone->a_flags |= (RICHACL_WRITE_THROUGH | RICHACL_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/fs/richacl_inode.c b/fs/richacl_inode.c index c0458db..e3cf9dd 100644 --- a/fs/richacl_inode.c +++ b/fs/richacl_inode.c @@ -222,3 +222,33 @@ out: return denied ? -EACCES : 0; } EXPORT_SYMBOL_GPL(richacl_permission); + +/** + * richacl_chmod - filesystem chmod helper + * @inode: inode whose file permission bits to change + * @mode: new file permission bits including the file type + * + * Helper for filesystems to use to perform a chmod on the richacl of an inode. + */ +int +richacl_chmod(struct inode *inode, mode_t mode) +{ + struct richacl *acl; + int retval; + + if (S_ISLNK(mode)) + return -EOPNOTSUPP; + if (!inode->i_op->set_richacl) + return -EOPNOTSUPP; + acl = get_richacl(inode); + if (IS_ERR_OR_NULL(acl)) + return PTR_ERR(acl); + acl = __richacl_chmod(acl, mode); + if (IS_ERR(acl)) + return PTR_ERR(acl); + retval = inode->i_op->set_richacl(inode, acl); + richacl_put(acl); + + return retval; +} +EXPORT_SYMBOL(richacl_chmod); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index 9fe0b63..51e8314 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -303,8 +303,10 @@ 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(unsigned int); extern void richacl_compute_max_masks(struct richacl *); +extern struct richacl *__richacl_chmod(struct richacl *, mode_t); /* richacl_inode.c */ extern int richacl_permission(struct inode *, const struct richacl *, int); +extern int richacl_chmod(struct inode *, mode_t); #endif /* __RICHACL_H */