From patchwork Wed Feb 25 23:41:32 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: 5885591 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 93BA79F373 for ; Wed, 25 Feb 2015 23:45:41 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id AE2F020374 for ; Wed, 25 Feb 2015 23:45:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B6AA320268 for ; Wed, 25 Feb 2015 23:45:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753908AbbBYXmZ (ORCPT ); Wed, 25 Feb 2015 18:42:25 -0500 Received: from mail-wg0-f44.google.com ([74.125.82.44]:42417 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753778AbbBYXmX (ORCPT ); Wed, 25 Feb 2015 18:42:23 -0500 Received: by wghl2 with SMTP id l2so6802799wgh.9; Wed, 25 Feb 2015 15:42:22 -0800 (PST) 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=cLAP9w+qhFe+PiRw8qFb385dXDNZvCLALbUAF0lUsr4=; b=meOHYzaOA2qEvsVEhKwHoCoJrGgWSLHmj49tyJ1cGPmJUtAlMZeZkydBb6Q126NEjO OPs+Pd9eIPl68yqswhkUL80OnILmxh3AhOIrm6S0hdqXVsSpFR5OXMQBNwLg/Cvhp1vs 6e81mvuFQnb+rK/FFkTW8Vxw0YybAjTD2pShYKTbzYhokDP1Iy7S4Wg0Xar5loZkcxN4 qkyHcVsU7cPjDAVZrgTsUqoIJgSNtrJt8U/cYAaEnMzh2wz7CiF3Bd62/qeOJ7JcdGZg hyG16UVdnmBD7kEhWcxm/9K8Bc8F0S0aJJTMS4TfDP0gwS5mZIpmNVO+Ce4e2rgYMGVW 38SA== X-Received: by 10.180.96.168 with SMTP id dt8mr45277873wib.82.1424907742290; Wed, 25 Feb 2015 15:42:22 -0800 (PST) Received: from nuc.home.com (80-110-112-196.cgn.dynamic.surfer.at. [80.110.112.196]) by mx.google.com with ESMTPSA id vh8sm66946337wjc.12.2015.02.25.15.42.20 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 25 Feb 2015 15:42:20 -0800 (PST) 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 11/21] richacl: Update the file masks in chmod() Date: Thu, 26 Feb 2015 00:41:32 +0100 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 Doing a chmod() sets the file mode, which includes the file permission bits. When a file has a richacl, the permissions that the richacl grants need to be limited to what the new file permission bits allow. This is done by setting the file masks in the richacl to what the file permission bits map to. The richacl access check algorithm takes the file masks into account, which ensures that the richacl cannot grant too many permissions. It is possible to explicitly add permissions to the file masks which go beyond what the file permission bits can grant (like the ACE4_WRITE_ACL permission). The POSIX.1 standard calls this an alternate file access control mechanism. A subsequent chmod() would ensure that those permissions are disabled again. Signed-off-by: Andreas Gruenbacher --- fs/richacl_base.c | 40 ++++++++++++++++++++++++++++++++++++++++ include/linux/richacl.h | 1 + 2 files changed, 41 insertions(+) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index 683bde2..7de2e9e 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -300,3 +300,43 @@ restart: acl->a_flags &= ~ACL4_MASKED; } EXPORT_SYMBOL_GPL(richacl_compute_max_masks); + +/** + * richacl_chmod - update the file masks to reflect the new mode + * @mode: new file permission bits + * + * Return a copy of @acl where the file masks have been replaced by the file + * masks corresponding to the file permission bits in @mode, or returns @acl + * itself if the file masks are already up to date. Takes over a reference + * to @acl. + */ +struct richacl * +richacl_chmod(struct richacl *acl, mode_t mode) +{ + unsigned int owner_mask, group_mask, other_mask; + struct richacl *clone; + + owner_mask = richacl_mode_to_mask(mode >> 6) | + ACE4_POSIX_OWNER_ALLOWED; + group_mask = richacl_mode_to_mask(mode >> 3); + other_mask = richacl_mode_to_mask(mode); + + if (acl->a_owner_mask == owner_mask && + acl->a_group_mask == group_mask && + acl->a_other_mask == other_mask && + (acl->a_flags & ACL4_MASKED)) + return acl; + + clone = richacl_clone(acl); + richacl_put(acl); + if (!clone) + return ERR_PTR(-ENOMEM); + + clone->a_flags |= ACL4_MASKED; + clone->a_owner_mask = owner_mask; + clone->a_group_mask = group_mask; + clone->a_other_mask = other_mask; + + return clone; +} +EXPORT_SYMBOL_GPL(richacl_chmod); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index 05d79ac..f347125 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -291,5 +291,6 @@ extern int richacl_masks_to_mode(const struct richacl *); extern unsigned int richacl_mode_to_mask(mode_t); 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); #endif /* __RICHACL_H */