From patchwork Fri Apr 24 11:04:15 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: 6268521 Return-Path: X-Original-To: patchwork-linux-nfs@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 AD2BEBF4A6 for ; Fri, 24 Apr 2015 11:16:35 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D958820225 for ; Fri, 24 Apr 2015 11:16:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E1EF6201E4 for ; Fri, 24 Apr 2015 11:16:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965871AbbDXLP6 (ORCPT ); Fri, 24 Apr 2015 07:15:58 -0400 Received: from mail-wi0-f171.google.com ([209.85.212.171]:37999 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754637AbbDXLFR (ORCPT ); Fri, 24 Apr 2015 07:05:17 -0400 Received: by wiun10 with SMTP id n10so16030505wiu.1; Fri, 24 Apr 2015 04:05:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:subject:date:message-id:in-reply-to:references:in-reply-to :references; bh=DYeNhLW6rh90V4o7l8m5y7zE0vCfaZ6vyXk0qGoMeA0=; b=oK1jt2s8g0XQkaFIBE/+21r+8fEMQmF8QyNyTaN3dGzpqDTrxU9yye6QeJpGn7egZk VVQHrgZyaItapIibn5peUQGyJoyZ+M5J54d4z7ZQUOBGycCVAPtABDkafAFiTXDBD5JE b2A+EJr4kRrdi5lSiEXIBy74vdmAA4KrQ5k2CirwPESE4MQcgHQ53vJABxibuw/Gpy9M OHraMZN3LyITYaPZz3KAhP0QGJxG/tk6BKVO/f43Iit6FMRBmjczSzeqw2oRViRNgP1p 2oYMkscQccq1F4sFPGeFtXvbGV2PyIYpD0pqcg481uPE4wX8v753VxuYq7NHBAPm7018 UHGA== X-Received: by 10.194.91.129 with SMTP id ce1mr14907010wjb.53.1429873515076; Fri, 24 Apr 2015 04:05:15 -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.3.2015.04.24.04.05.13 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 Apr 2015 04:05:14 -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 Subject: [RFC v3 18/45] richacl: Check if an acl is equivalent to a file mode Date: Fri, 24 Apr 2015 13:04:15 +0200 Message-Id: <0be8f34af68a3f00810e3a9628ece183338d9d3b.1429868795.git.agruenba@redhat.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Spam-Status: No, score=-6.8 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 This function is used to avoid storing richacls if the acl can be computed from the file permission bits. Signed-off-by: Andreas Gruenbacher --- fs/richacl_base.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/richacl.h | 1 + 2 files changed, 49 insertions(+) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index 5d45539..db27542 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -437,3 +437,51 @@ richacl_inherit(const struct richacl *dir_acl, int isdir) return acl; } + +/** + * richacl_equiv_mode - check if @acl is equivalent to file permission bits + * @mode_p: the file mode (including the file type) + * + * If @acl can be fully represented by file permission bits, this function + * returns 0, and the file permission bits in @mode_p are set to the equivalent + * of @acl. + * + * This function is used to avoid storing richacls on disk if the acl can be + * computed from the file permission bits. It allows user-space to make sure + * that a file has no explicit richacl set. + */ +int +richacl_equiv_mode(const struct richacl *acl, mode_t *mode_p) +{ + const struct richace *ace = acl->a_entries; + unsigned int x; + mode_t mask; + + if (acl->a_count != 1 || + acl->a_flags != RICHACL_MASKED || + !richace_is_everyone(ace) || + !richace_is_allow(ace) || + ace->e_flags & ~RICHACE_SPECIAL_WHO) + return -1; + + /* Mask flags we can ignore */ + x = ~RICHACE_POSIX_ALWAYS_ALLOWED; + if (!S_ISDIR(*mode_p)) + x &= ~RICHACE_DELETE_CHILD; + + mask = richacl_masks_to_mode(acl); + if (((acl->a_group_mask ^ richacl_mode_to_mask(mask >> 3)) & x) || + ((acl->a_other_mask ^ richacl_mode_to_mask(mask)) & x)) + return -1; + + x &= ~RICHACE_POSIX_OWNER_ALLOWED; + if ((acl->a_owner_mask ^ richacl_mode_to_mask(mask >> 6)) & x) + return -1; + + if ((ace->e_mask ^ RICHACE_POSIX_MODE_ALL) & x) + return -1; + + *mode_p = (*mode_p & ~S_IRWXUGO) | mask; + return 0; +} +EXPORT_SYMBOL_GPL(richacl_equiv_mode); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index ab9fde1..c6fd0a1 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -297,6 +297,7 @@ 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); extern struct richacl *richacl_inherit(const struct richacl *, int); +extern int richacl_equiv_mode(const struct richacl *, mode_t *); /* richacl_inode.c */ extern int richacl_permission(struct inode *, const struct richacl *, int);