From patchwork Fri Oct 16 15:17:52 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Gruenbacher X-Patchwork-Id: 7418281 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 D45869F1D5 for ; Fri, 16 Oct 2015 16:03:00 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E8BB4208E1 for ; Fri, 16 Oct 2015 16:02:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DF215206E0 for ; Fri, 16 Oct 2015 16:02:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932784AbbJPPUL (ORCPT ); Fri, 16 Oct 2015 11:20:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39864 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932728AbbJPPUH (ORCPT ); Fri, 16 Oct 2015 11:20:07 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id 6898DC0B64D5; Fri, 16 Oct 2015 15:20:07 +0000 (UTC) Received: from nux.redhat.com (vpn1-5-224.ams2.redhat.com [10.36.5.224]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t9GFIRbv011947; Fri, 16 Oct 2015 11:20:01 -0400 From: Andreas Gruenbacher To: Alexander Viro , "Theodore Ts'o" , Andreas Dilger , "J. Bruce Fields" , Jeff Layton , Trond Myklebust , Anna Schumaker , Dave Chinner , linux-ext4@vger.kernel.org, xfs@oss.sgi.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-api@vger.kernel.org Subject: [PATCH v11 14/48] richacl: Check if an acl is equivalent to a file mode Date: Fri, 16 Oct 2015 17:17:52 +0200 Message-Id: <1445008706-15115-15-git-send-email-agruenba@redhat.com> In-Reply-To: <1445008706-15115-1-git-send-email-agruenba@redhat.com> References: <1445008706-15115-1-git-send-email-agruenba@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, 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 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 Reviewed-by: J. Bruce Fields --- fs/richacl_base.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/richacl.h | 1 + 2 files changed, 105 insertions(+) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index 764d73a..f4b8d3c 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -382,3 +382,107 @@ __richacl_chmod(struct richacl *acl, umode_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, umode_t *mode_p) +{ + umode_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_WRITE_THROUGH | 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) { + if (acl->a_flags & RICHACL_WRITE_THROUGH) { + owner.allowed = acl->a_owner_mask; + everyone.allowed = acl->a_other_mask; + } else { + owner.allowed &= acl->a_owner_mask; + everyone.allowed &= acl->a_other_mask; + } + group.allowed &= acl->a_group_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 e42e882..49d84dd 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -222,6 +222,7 @@ extern unsigned int richacl_mode_to_mask(umode_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 *, umode_t); +extern int richacl_equiv_mode(const struct richacl *, umode_t *); /* richacl_inode.c */ extern int richacl_permission(struct inode *, const struct richacl *, int);