From patchwork Fri Apr 24 11:04:10 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: 6268921 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 DF5659F1BE for ; Fri, 24 Apr 2015 11:19:27 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 18AD120251 for ; Fri, 24 Apr 2015 11:19:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2D1B42022A for ; Fri, 24 Apr 2015 11:19:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933610AbbDXLRX (ORCPT ); Fri, 24 Apr 2015 07:17:23 -0400 Received: from mail-wi0-f170.google.com ([209.85.212.170]:35262 "EHLO mail-wi0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754699AbbDXLFJ (ORCPT ); Fri, 24 Apr 2015 07:05:09 -0400 Received: by widdi4 with SMTP id di4so17550795wid.0; Fri, 24 Apr 2015 04:05:08 -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=f3NYWB5sr0kaiMWAE+GEf8jXIybjNQK+6cx4Er8j9jc=; b=f/LYrejDGEm6cxC+jc1IwLtogx9ZeO63bpPF2+2vbYwK/Z3AlKGcFKOix240EWkBS0 lDWaPHsSb6VfjjTWHtlnOFWyNrQGB0HMeaKqs3l4Bx1ZaK54hX/77YahxRoehEpE1QNF HoJSfNsXemoeZJJStR1KmHqR8KHIE8vyFI6etSpLqL0vViIsLznZwAwhZAZ3TbMW8UdX djJAxK1j6Y5uKZNssAfp34/55njlNeCQZ3Wqbn5Z9fgcJP5mRENLo4w7Al8CyInjbi/W RJG7peFBsRf8as7mwjQFE+R6hwcuOvVvgND8RJ1VVZuuXqfpmRjZo8JlmJMSgg49cKIk DTOA== X-Received: by 10.194.78.49 with SMTP id y17mr14911359wjw.131.1429873508147; Fri, 24 Apr 2015 04:05:08 -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.3.2015.04.24.04.05.06 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 Apr 2015 04:05:07 -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 13/45] richacl: Update the file masks in chmod() Date: Fri, 24 Apr 2015 13:04:10 +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 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 1e14c38..261ddd2 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -326,3 +326,43 @@ restart: acl->a_flags &= ~RICHACL_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) | + RICHACE_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 & RICHACL_MASKED)) + return acl; + + clone = richacl_clone(acl, GFP_KERNEL); + richacl_put(acl); + if (!clone) + return ERR_PTR(-ENOMEM); + + clone->a_flags |= RICHACL_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 cd0cdaa..a27ff10 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -290,5 +290,6 @@ 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 */