From patchwork Wed Jul 22 13:03:00 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: 6843741 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 29B08C05AC for ; Wed, 22 Jul 2015 13:21:53 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2E3BB206D0 for ; Wed, 22 Jul 2015 13:21:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2407320544 for ; Wed, 22 Jul 2015 13:21:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756708AbbGVNEU (ORCPT ); Wed, 22 Jul 2015 09:04:20 -0400 Received: from mail-wi0-f177.google.com ([209.85.212.177]:35055 "EHLO mail-wi0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752929AbbGVNER (ORCPT ); Wed, 22 Jul 2015 09:04:17 -0400 Received: by wibxm9 with SMTP id xm9so162587121wib.0; Wed, 22 Jul 2015 06:04:15 -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=YpFhYwAKMDwXiDy3++yWuWv4wecHam/Vq7UFGduVVe8=; b=jZHq/ljuoXiW6eTiErbquqkTsHBrEDqhPKfzDkisl2GjvC/C/u4A80yXXosc3Iocjw W+cGevpZTxgBfdrpROOqku7axOfnWByOxWiAYC4CP91xUKudkzoojO2VXhgPf0tHoEtA 0Bkh9/9Lk8ofLT8/KUht/X5ywbTCsv+mVo4kkZpWVagrp+7uAYuFAJFAVLJSKezvYUI8 qo4V5AyPKtbPrqbLjFjDHICFmkdTLh8AD//xw9nNIm9Tt3mmjp8lVmbeUh0VnHcmBlWH ajiJXCLvhT2IEmHDQKoslIO/kkoc0WhAyx0JSelskEWJcTUZO0tigSR2dGHainmRxyEa 0x0Q== X-Received: by 10.194.82.167 with SMTP id j7mr4888325wjy.123.1437570255629; Wed, 22 Jul 2015 06:04:15 -0700 (PDT) Received: from schleppi.home.com ([149.14.88.26]) by smtp.gmail.com with ESMTPSA id u7sm21992628wif.3.2015.07.22.06.04.13 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 Jul 2015 06:04:14 -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 Subject: [PATCH v5 10/39] richacl: Permission check algorithm Date: Wed, 22 Jul 2015 15:03:00 +0200 Message-Id: <1437570209-29832-11-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 A richacl roughly grants a requested access if the NFSv4 acl in the richacl grants the requested permissions according to the NFSv4 permission check algorithm and the file mask that applies to the process includes the requested permissions. Signed-off-by: Andreas Gruenbacher --- fs/Makefile | 2 +- fs/richacl_inode.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/richacl.h | 3 ++ 3 files changed, 124 insertions(+), 1 deletion(-) create mode 100644 fs/richacl_inode.c diff --git a/fs/Makefile b/fs/Makefile index ddc43d8..1305047 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -48,7 +48,7 @@ obj-$(CONFIG_SYSCTL) += drop_caches.o obj-$(CONFIG_FHANDLE) += fhandle.o obj-$(CONFIG_FS_RICHACL) += richacl.o -richacl-y := richacl_base.o +richacl-y := richacl_base.o richacl_inode.o obj-y += quota/ diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c new file mode 100644 index 0000000..63f3b87 --- /dev/null +++ b/fs/richacl_inode.c @@ -0,0 +1,120 @@ +/* + * Copyright (C) 2010 Novell, Inc. + * Copyright (C) 2015 Red Hat, Inc. + * Written by Andreas Gruenbacher + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2, or (at your option) any + * later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ + +#include +#include +#include +#include +#include + +/** + * richacl_permission - richacl permission check algorithm + * @inode: inode to check + * @acl: rich acl of the inode + * @want: requested access (MAY_* flags) + * + * Checks if the current process is granted @mask flags in @acl. + */ +int +richacl_permission(struct inode *inode, const struct richacl *acl, + int want) +{ + const struct richace *ace; + unsigned int mask = richacl_want_to_mask(want); + unsigned int requested = mask, denied = 0; + int in_owning_group = in_group_p(inode->i_gid); + int in_owner_or_group_class = in_owning_group; + + /* + * A process is + * - in the owner file class if it owns the file, + * - in the group file class if it is in the file's owning group or + * it matches any of the user or group entries, and + * - in the other file class otherwise. + * The file class is only relevant for determining which file mask to + * apply, which only happens for masked acls. + */ + if (acl->a_flags & RICHACL_MASKED) { + if (uid_eq(current_fsuid(), inode->i_uid)) { + denied = requested & ~acl->a_owner_mask; + goto out; + } + } else { + /* + * We don't care which class the process is in when the acl is + * not masked. + */ + in_owner_or_group_class = 1; + } + + /* + * Check if the acl grants the requested access and determine which + * file class the process is in. + */ + richacl_for_each_entry(ace, acl) { + unsigned int ace_mask = ace->e_mask; + + if (richace_is_inherit_only(ace)) + continue; + if (richace_is_owner(ace)) { + if (!uid_eq(current_fsuid(), inode->i_uid)) + continue; + } else if (richace_is_group(ace)) { + if (!in_owning_group) + continue; + } else if (richace_is_unix_user(ace)) { + if (!uid_eq(current_fsuid(), ace->e_id.uid)) + continue; + } else if (richace_is_unix_group(ace)) { + if (!in_group_p(ace->e_id.gid)) + continue; + } else + goto entry_matches_everyone; + + /* The process is in the owner or group file class. */ + in_owner_or_group_class = 1; + +entry_matches_everyone: + /* Check which mask flags the ACE allows or denies. */ + if (richace_is_deny(ace)) + denied |= ace_mask & mask; + mask &= ~ace_mask; + + /* + * Keep going until we know which file class + * the process is in. + */ + if (!mask && in_owner_or_group_class) + break; + } + denied |= mask; + + if (acl->a_flags & RICHACL_MASKED) { + /* + * The file class a process is in determines which file mask + * applies. Check if that file mask also grants the requested + * access. + */ + if (in_owner_or_group_class) + denied |= requested & ~acl->a_group_mask; + else + denied = requested & ~acl->a_other_mask; + } + +out: + return denied ? -EACCES : 0; +} +EXPORT_SYMBOL_GPL(richacl_permission); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index e4266dd..1500824 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -304,4 +304,7 @@ extern unsigned int richacl_want_to_mask(unsigned int); extern void richacl_compute_max_masks(struct richacl *, kuid_t); extern struct richacl *richacl_chmod(struct richacl *, mode_t); +/* richacl_inode.c */ +extern int richacl_permission(struct inode *, const struct richacl *, int); + #endif /* __RICHACL_H */