From patchwork Wed Jul 22 13:03:03 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: 6843431 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 E58839F457 for ; Wed, 22 Jul 2015 13:16:36 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 00599206D4 for ; Wed, 22 Jul 2015 13:16:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B5A29206D0 for ; Wed, 22 Jul 2015 13:16:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756797AbbGVNE2 (ORCPT ); Wed, 22 Jul 2015 09:04:28 -0400 Received: from mail-wi0-f179.google.com ([209.85.212.179]:33862 "EHLO mail-wi0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756692AbbGVNEV (ORCPT ); Wed, 22 Jul 2015 09:04:21 -0400 Received: by wibud3 with SMTP id ud3so153260692wib.1; Wed, 22 Jul 2015 06:04:19 -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=OHjPPARfsBb5zGh2m0GOYIkANYv6dyCev97Oti39IYM=; b=tSkZaR1qskrz5TiwURcyh5Nsq7jZELi+zPlIBS8qUAzVScUs8fZG/RKPIR6prgVWwQ F+InXLjkxyxOE3lYHWUqHG5CEAtUdR015g2n9alJ0Xs+ptTcyGARFZLpQaqGdXoBWRGk 20qFlm3u9CzdPoDaarwugibGVccNVFgWrMcRm3b73N0b8x/zB00rkGNNWWS5djsNjzYm w+ioLXYxk/7HwSGNAKkSi8bcN4PwEIGXVXZ7r3ULgVKy+fDcVnmpkxGrGJPE0hkFl3wr mNpH5RFnluUTZOGhXrckCLqCl70n7smOHfChEnz/h57MxaJyQDcjd5NfMcRLUAMQ1QnX JaOQ== X-Received: by 10.194.176.201 with SMTP id ck9mr4943159wjc.108.1437570259560; Wed, 22 Jul 2015 06:04:19 -0700 (PDT) Received: from schleppi.home.com ([149.14.88.26]) by smtp.gmail.com with ESMTPSA id u7sm21992628wif.3.2015.07.22.06.04.18 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 Jul 2015 06:04:19 -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 13/39] richacl: Check if an acl is equivalent to a file mode Date: Wed, 22 Jul 2015 15:03:03 +0200 Message-Id: <1437570209-29832-14-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 ACLs are considered equivalent to file modes if they only consist of owner@, group@, and everyone@ entries, the owner@ permissions do not depend on whether the owner is a member in the owning group, and no inheritance flags are set. This test 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 | 95 +++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/richacl.h | 1 + 2 files changed, 96 insertions(+) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index 3c13535..333faa9 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -374,3 +374,98 @@ richacl_chmod(struct richacl *acl, mode_t mode) return clone; } EXPORT_SYMBOL_GPL(richacl_chmod); + +/** + * richacl_equiv_mode - compute the mode equivalent of @acl + * + * An acl is considered equivalent to a file mode if it only consists of + * owner@, group@, and everyone@ entries and the owner@ permissions do not + * depend on whether the owner is a member in the owning group. + */ +int +richacl_equiv_mode(const struct richacl *acl, mode_t *mode_p) +{ + mode_t mode = *mode_p; + + /* + * The RICHACE_DELETE_CHILD flag is meaningless for non-directories, so + * we ignore it. + */ + unsigned int x = S_ISDIR(mode) ? 0 : RICHACE_DELETE_CHILD; + struct { + unsigned int allowed; + unsigned int defined; /* allowed or denied */ + } owner = { + .defined = RICHACE_POSIX_ALWAYS_ALLOWED | RICHACE_POSIX_OWNER_ALLOWED | x, + }, group = { + .defined = RICHACE_POSIX_ALWAYS_ALLOWED | x, + }, everyone = { + .defined = RICHACE_POSIX_ALWAYS_ALLOWED | x, + }; + const struct richace *ace; + + if (acl->a_flags & ~RICHACL_MASKED) + return -1; + + richacl_for_each_entry(ace, acl) { + if (ace->e_flags & ~RICHACE_SPECIAL_WHO) + return -1; + + if (richace_is_owner(ace) || richace_is_everyone(ace)) { + x = ace->e_mask & ~owner.defined; + if (richace_is_allow(ace)) { + unsigned int group_denied = group.defined & ~group.allowed; + + if (x & group_denied) + return -1; + owner.allowed |= x; + } else /* if (richace_is_deny(ace)) */ { + if (x & group.allowed) + return -1; + } + owner.defined |= x; + + if (richace_is_everyone(ace)) { + x = ace->e_mask; + if (richace_is_allow(ace)) { + group.allowed |= x & ~group.defined; + everyone.allowed |= x & ~everyone.defined; + } + group.defined |= x; + everyone.defined |= x; + } + } else if (richace_is_group(ace)) { + x = ace->e_mask & ~group.defined; + if (richace_is_allow(ace)) + group.allowed |= x; + group.defined |= x; + } else + return -1; + } + + if (group.allowed & ~owner.defined) + return -1; + + if (acl->a_flags & RICHACL_MASKED) { + owner.allowed = acl->a_owner_mask; + group.allowed &= acl->a_group_mask; + everyone.allowed = acl->a_other_mask; + } + + mode = (mode & ~S_IRWXUGO) | + (richacl_mask_to_mode(owner.allowed) << 6) | + (richacl_mask_to_mode(group.allowed) << 3) | + richacl_mask_to_mode(everyone.allowed); + + /* Mask flags we can ignore */ + x = S_ISDIR(mode) ? 0 : RICHACE_DELETE_CHILD; + + if (((richacl_mode_to_mask(mode >> 6) ^ owner.allowed) & ~x) || + ((richacl_mode_to_mask(mode >> 3) ^ group.allowed) & ~x) || + ((richacl_mode_to_mask(mode) ^ everyone.allowed) & ~x)) + return -1; + + *mode_p = mode; + return 0; +} +EXPORT_SYMBOL_GPL(richacl_equiv_mode); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index f59ffa73..03876cd 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -308,6 +308,7 @@ 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 *, kuid_t); extern struct richacl *richacl_chmod(struct richacl *, mode_t); +extern int richacl_equiv_mode(const struct richacl *, mode_t *); /* richacl_inode.c */ extern int richacl_permission(struct inode *, const struct richacl *, int);