From patchwork Fri Apr 24 11:04:23 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: 6267711 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 19A2F9F6E1 for ; Fri, 24 Apr 2015 11:05:48 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2C366200F3 for ; Fri, 24 Apr 2015 11:05:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 32639201E4 for ; Fri, 24 Apr 2015 11:05:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964900AbbDXLFb (ORCPT ); Fri, 24 Apr 2015 07:05:31 -0400 Received: from mail-wi0-f171.google.com ([209.85.212.171]:36217 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932859AbbDXLF1 (ORCPT ); Fri, 24 Apr 2015 07:05:27 -0400 Received: by wizk4 with SMTP id k4so17551981wiz.1; Fri, 24 Apr 2015 04:05:26 -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 :in-reply-to:references; bh=NnvSq34y8mB3LpFZqfluwj3YWlj9slOW9rTU4Xwv3dM=; b=VQ3gVmCi0NUVlGcprppb3pK8mPza4LgaRBGQ7QV4RlCKaq/sGKBSGZhmUFzDzPQT8j 1srG9y/VmZ+QJO9m467InQap2sWDgegpu0j8E/Wo6ppZ/2k8FASPpKAqpZ1hGlmY9Yr0 psP8I6ZYcmv3n/ss2bLAyfGIDTmZKdODoS0hWQSnBbouGgBcnKv8hex3cJs3MgPpkMIQ J9pmYGWdOEr4m2bNvNByyowNUzGf/IcguweOtgl5TGZ+Pi3tJyFsp0LUFlItEDCbfp9U NscdcK2WOStB+uvEO2oSeAdO3TIauhgSRTyf9w6KEgSEF/8Wo0PvwE2aIbd0MlOdc5M9 bTHg== X-Received: by 10.194.57.209 with SMTP id k17mr14330917wjq.33.1429873526090; Fri, 24 Apr 2015 04:05:26 -0700 (PDT) Received: from nuc.home.com (80-110-112-232.cgn.dynamic.surfer.at. [80.110.112.232]) by mx.google.com with ESMTPSA id ch6sm16410648wjc.3.2015.04.24.04.05.24 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 Apr 2015 04:05:25 -0700 (PDT) From: Andreas Gruenbacher X-Google-Original-From: Andreas Gruenbacher To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org Cc: Andreas Gruenbacher Subject: [RFC v3 26/45] richacl: Move everyone@ aces down the acl Date: Fri, 24 Apr 2015 13:04:23 +0200 Message-Id: X-Mailer: git-send-email 2.1.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, T_DKIM_INVALID, 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 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 everyone@ deny ace is needed. 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 2ea6658..63f4373 100644 --- a/fs/richacl_compat.c +++ b/fs/richacl_compat.c @@ -159,3 +159,68 @@ richace_change_mask(struct richacl_alloc *x, struct richace **ace, } return 0; } + +/** + * richacl_move_everyone_aces_down - move everyone@ aces to the end of the acl + * @x: 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 *x) +{ + struct richace *ace; + unsigned int allowed = 0, denied = 0; + + richacl_for_each_entry(ace, x->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(x, &ace, 0)) + return -1; + } else { + if (richace_is_allow(ace)) { + if (richace_change_mask(x, &ace, allowed | + (ace->e_mask & ~denied))) + return -1; + } else if (richace_is_deny(ace)) { + if (richace_change_mask(x, &ace, denied | + (ace->e_mask & ~allowed))) + return -1; + } + } + } + if (allowed & ~RICHACE_POSIX_ALWAYS_ALLOWED) { + struct richace *last_ace = ace - 1; + + if (x->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(x, &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; +}