From patchwork Sat Sep 5 10:27:16 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Gruenbacher X-Patchwork-Id: 7128511 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 8E1D6BEEC1 for ; Sat, 5 Sep 2015 10:37:58 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A8E072081D for ; Sat, 5 Sep 2015 10:37:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B5D4620787 for ; Sat, 5 Sep 2015 10:37:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752856AbbIEK3X (ORCPT ); Sat, 5 Sep 2015 06:29:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58420 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752010AbbIEK2S (ORCPT ); Sat, 5 Sep 2015 06:28:18 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id 6A9E2461D4; Sat, 5 Sep 2015 10:28:18 +0000 (UTC) Received: from nuc.home.com (vpn1-7-178.ams2.redhat.com [10.36.7.178]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t85ARbEE023920; Sat, 5 Sep 2015 06:28:16 -0400 From: Andreas Gruenbacher To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-api@vger.kernel.org, linux-cifs@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Andreas Gruenbacher Subject: [RFC v7 21/41] richacl: Move everyone@ aces down the acl Date: Sat, 5 Sep 2015 12:27:16 +0200 Message-Id: <1441448856-13478-22-git-send-email-agruenba@redhat.com> In-Reply-To: <1441448856-13478-1-git-send-email-agruenba@redhat.com> References: <1441448856-13478-1-git-send-email-agruenba@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, SUSPICIOUS_RECIPS, 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 The POSIX standard puts processes which are not the owner or a member in the owning group or which match any ace other then everyone@ on the other file class. We only know if a process is in the other class after processing the entire acl. Move all everyone@ aces in the acl down in the acl so that at most a single everyone@ allow ace remains at the end. Permissions which are not explicitly allowed are implicitly denied, so an everyone@ deny ace is unneeded. The everyone@ aces can be moved down the acl without changing the permissions that the acl grants. This transformation simplifies the following algorithms, and eventually allows us to turn the final everyone@ allow ace into an entry for the other class. Signed-off-by: Andreas Gruenbacher --- fs/richacl_compat.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) diff --git a/fs/richacl_compat.c b/fs/richacl_compat.c index 341e429..4f0acf5 100644 --- a/fs/richacl_compat.c +++ b/fs/richacl_compat.c @@ -153,3 +153,68 @@ richace_change_mask(struct richacl_alloc *alloc, struct richace **ace, } return 0; } + +/** + * richacl_move_everyone_aces_down - move everyone@ aces to the end of the acl + * @alloc: acl and number of allocated entries + * + * Move all everyone aces to the end of the acl so that only a single everyone@ + * allow ace remains at the end, and update the mask fields of all aces on the + * way. The last ace of the resulting acl will be an everyone@ allow ace only + * if @acl grants any permissions to @everyone. No @everyone deny aces will + * remain. + * + * This transformation does not alter the permissions that the acl grants. + * Having at most one everyone@ allow ace at the end of the acl helps us in the + * following algorithms. + */ +static int +richacl_move_everyone_aces_down(struct richacl_alloc *alloc) +{ + struct richace *ace; + unsigned int allowed = 0, denied = 0; + + richacl_for_each_entry(ace, alloc->acl) { + if (richace_is_inherit_only(ace)) + continue; + if (richace_is_everyone(ace)) { + if (richace_is_allow(ace)) + allowed |= (ace->e_mask & ~denied); + else if (richace_is_deny(ace)) + denied |= (ace->e_mask & ~allowed); + else + continue; + if (richace_change_mask(alloc, &ace, 0)) + return -1; + } else { + if (richace_is_allow(ace)) { + if (richace_change_mask(alloc, &ace, allowed | + (ace->e_mask & ~denied))) + return -1; + } else if (richace_is_deny(ace)) { + if (richace_change_mask(alloc, &ace, denied | + (ace->e_mask & ~allowed))) + return -1; + } + } + } + if (allowed & ~RICHACE_POSIX_ALWAYS_ALLOWED) { + struct richace *last_ace = ace - 1; + + if (alloc->acl->a_entries && + richace_is_everyone(last_ace) && + richace_is_allow(last_ace) && + richace_is_inherit_only(last_ace) && + last_ace->e_mask == allowed) + last_ace->e_flags &= ~RICHACE_INHERIT_ONLY_ACE; + else { + if (richacl_insert_entry(alloc, &ace)) + return -1; + ace->e_type = RICHACE_ACCESS_ALLOWED_ACE_TYPE; + ace->e_flags = RICHACE_SPECIAL_WHO; + ace->e_mask = allowed; + ace->e_id.special = RICHACE_EVERYONE_SPECIAL_ID; + } + } + return 0; +}