From patchwork Fri Apr 24 11:04:16 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: 6268531 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 BD5A59F1C4 for ; Fri, 24 Apr 2015 11:16:41 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9C1F820225 for ; Fri, 24 Apr 2015 11:16:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 786F1201E4 for ; Fri, 24 Apr 2015 11:16:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932722AbbDXLP5 (ORCPT ); Fri, 24 Apr 2015 07:15:57 -0400 Received: from mail-wi0-f182.google.com ([209.85.212.182]:36014 "EHLO mail-wi0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754734AbbDXLFR (ORCPT ); Fri, 24 Apr 2015 07:05:17 -0400 Received: by wizk4 with SMTP id k4so17546817wiz.1; Fri, 24 Apr 2015 04:05:16 -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=O3wMFNnocFcT+5BxKMhqfbAATwB5uACLuLpX98EGf74=; b=npDkqAXwkIl1+VZxGupg1gJMFGs4U+gST7qPIqUQXohX6dbajMByOLKA1rWo4T2oyU 9MgFMmNQiU0J2TdwuffRnrCEXIISlvuiYdnpHpylw4mb5vjlazqkh8CjYNhrFMm7aH+c rcJa8JbmsT9hKylnaLVe2yXxdks8rJ5N322ciiU1OEMfd2OAqYR858rMAQ9hY6Lzdigz +bYrKSTGwWW/7Tbow9iSAQ1kXEK5kYgPXh+f4nVYnZhjydl9xx/oNfb4MfICZBh/wO16 1Pm/ZlImMWSbC/pBi89hRwb4PytrtZQz12ZJWfQ7f6saRv6Exe8b6fry045l91PIvrMp Wc9g== X-Received: by 10.180.79.227 with SMTP id m3mr2815242wix.71.1429873516339; Fri, 24 Apr 2015 04:05:16 -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.3.2015.04.24.04.05.15 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 Apr 2015 04:05:15 -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 19/45] richacl: Also recognize nontrivial mode-equivalent acls Date: Fri, 24 Apr 2015 13:04:16 +0200 Message-Id: <5e9ee3b123b3d648487cd18dc906b6a2cd23085b.1429868795.git.agruenba@redhat.com> 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 So far, richacl_equiv_mode() is relatively limited in the types of acl it considers equivalent to a file mode: it only accepts masked acls with a single everyone@:rwpxd::allow entry. Change this to consider all acls equivalent to file modes if they only consist of owner@, group@, and everyone@ entries and the owner@ permissions do not depend on whether the owner is a member in the owning group. Signed-off-by: Andreas Gruenbacher --- fs/richacl_base.c | 150 ++++++++++++++++++++++++++++++++++++++---------- include/linux/richacl.h | 1 + 2 files changed, 122 insertions(+), 29 deletions(-) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index db27542..54cb482 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -439,49 +439,141 @@ richacl_inherit(const struct richacl *dir_acl, int isdir) } /** - * richacl_equiv_mode - check if @acl is equivalent to file permission bits - * @mode_p: the file mode (including the file type) + * __richacl_equiv_mode - compute the mode equivalent of @acl * - * 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 does not consider the masks in @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. + * 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) +__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) + 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 = { + .allowed = RICHACE_POSIX_ALWAYS_ALLOWED, + .defined = RICHACE_POSIX_ALWAYS_ALLOWED | RICHACE_POSIX_OWNER_ALLOWED | x, + }, group = { + .allowed = RICHACE_POSIX_ALWAYS_ALLOWED, + .defined = RICHACE_POSIX_ALWAYS_ALLOWED | x, + }, everyone = { + .allowed = RICHACE_POSIX_ALWAYS_ALLOWED, + .defined = RICHACE_POSIX_ALWAYS_ALLOWED | x, + }; + const struct richace *ace; + + 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; - /* Mask flags we can ignore */ - x = ~RICHACE_POSIX_ALWAYS_ALLOWED; - if (!S_ISDIR(*mode_p)) - x &= ~RICHACE_DELETE_CHILD; + if (acl->a_flags & RICHACL_MASKED) { + owner.allowed &= acl->a_owner_mask; + group.allowed &= acl->a_group_mask; + everyone.allowed &= acl->a_other_mask; + } - 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)) + 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; - x &= ~RICHACE_POSIX_OWNER_ALLOWED; - if ((acl->a_owner_mask ^ richacl_mode_to_mask(mask >> 6)) & x) + *mode_p = mode; + return 0; +} +EXPORT_SYMBOL_GPL(__richacl_equiv_mode); + +/** + * richacl_equiv_mode - determine if @acl is equivalent to a file mode + * @mode_p: the file mode + * + * The file type in @mode_p must be set when calling richacl_equiv_mode(). + * + * Returns with 0 if @acl is equivalent to a file mode; in that case, the + * file permission bits in @mode_p are set to the mode equivalent of @acl. + */ +int +richacl_equiv_mode(const struct richacl *acl, mode_t *mode_p) +{ + mode_t mode = *mode_p; + + if (acl->a_flags & ~RICHACL_MASKED) return -1; - if ((ace->e_mask ^ RICHACE_POSIX_MODE_ALL) & x) + if (__richacl_equiv_mode(acl, &mode)) return -1; - *mode_p = (*mode_p & ~S_IRWXUGO) | mask; + if (acl->a_flags & RICHACL_MASKED) { + mode_t mask = richacl_masks_to_mode(acl); + unsigned int x; + + /* Mask flags we can ignore */ + x = ~(RICHACE_POSIX_ALWAYS_ALLOWED | + (S_ISDIR(mode) ? 0 : RICHACE_DELETE_CHILD)); + + 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; + + mode &= ~S_IRWXUGO | mask; + } + + *mode_p = mode; return 0; } EXPORT_SYMBOL_GPL(richacl_equiv_mode); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index c6fd0a1..8a92b89 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 *); extern int richacl_equiv_mode(const struct richacl *, mode_t *); /* richacl_inode.c */