From patchwork Wed Jul 22 13:03:11 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Andreas_Gr=C3=BCnbacher?= X-Patchwork-Id: 6843341 Return-Path: X-Original-To: patchwork-linux-fsdevel@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 A4BC39F380 for ; Wed, 22 Jul 2015 13:14:48 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CA758206D4 for ; Wed, 22 Jul 2015 13:14:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 24699206D7 for ; Wed, 22 Jul 2015 13:14:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757135AbbGVNOG (ORCPT ); Wed, 22 Jul 2015 09:14:06 -0400 Received: from mail-wi0-f178.google.com ([209.85.212.178]:36789 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756832AbbGVNEb (ORCPT ); Wed, 22 Jul 2015 09:04:31 -0400 Received: by wicgb10 with SMTP id gb10so97400352wic.1; Wed, 22 Jul 2015 06:04:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=BQmwF28OV9mLJNK7g1bgm3j5l9p3Px8B8jE++/8oads=; b=gpqx/ajG76L31jGpKXiNH9eyGRoNa9qEgi8liZKilWG5cKbSGc1vZPNtu9RGeGOZQu M1HPfHFbxVk26dEOpTbioq2i5ywGkDlzLtR3LHi+Yaxqts8Qh0/RXFn1jp1Y6LANrFIR wubB18qlcqoY1kdFG0I3MR0nmgb1z0IwvY8VFrsLGB2f5fvviFc6zw0l1njoV8DnQ7Dp u9oOzM/OhmhX1gsusIPSfZVj43Z3LqJ8UADPMHfiE5T1nbkuoQC+QomxYbD0A5OBm6i+ Cug9+7rZiCbH0FhA4VdsyWQqVPyyZHlj1yZHD60FebixdxKebxKi6qiIQ/YdX1SxiCQM E4RA== X-Received: by 10.180.20.15 with SMTP id j15mr6414301wie.76.1437570269628; Wed, 22 Jul 2015 06:04:29 -0700 (PDT) Received: from schleppi.home.com ([149.14.88.26]) by smtp.gmail.com with ESMTPSA id u7sm21992628wif.3.2015.07.22.06.04.28 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 Jul 2015 06:04:28 -0700 (PDT) From: Andreas Gruenbacher To: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-api@vger.kernel.org, samba-technical@lists.samba.org, linux-security-module@vger.kernel.org, Andreas Gruenbacher , Andreas Gruenbacher Subject: [PATCH v5 21/39] richacl: Move everyone@ aces down the acl Date: Wed, 22 Jul 2015 15:03:11 +0200 Message-Id: <1437570209-29832-22-git-send-email-andreas.gruenbacher@gmail.com> X-Mailer: git-send-email 2.4.3 In-Reply-To: <1437570209-29832-1-git-send-email-andreas.gruenbacher@gmail.com> References: <1437570209-29832-1-git-send-email-andreas.gruenbacher@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-8.0 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, T_DKIM_INVALID, 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 From: Andreas Gruenbacher 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 5bbf993..e10ead3 100644 --- a/fs/richacl_compat.c +++ b/fs/richacl_compat.c @@ -152,3 +152,68 @@ 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; +}