From patchwork Wed Feb 23 13:52:01 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Aneesh Kumar K.V" X-Patchwork-Id: 584611 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p1NDugKx026232 for ; Wed, 23 Feb 2011 13:56:42 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932282Ab1BWN4F (ORCPT ); Wed, 23 Feb 2011 08:56:05 -0500 Received: from e28smtp09.in.ibm.com ([122.248.162.9]:38822 "EHLO e28smtp09.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932154Ab1BWN4C (ORCPT ); Wed, 23 Feb 2011 08:56:02 -0500 Received: from d28relay03.in.ibm.com (d28relay03.in.ibm.com [9.184.220.60]) by e28smtp09.in.ibm.com (8.14.4/8.13.1) with ESMTP id p1ND3pv7024279; Wed, 23 Feb 2011 18:33:51 +0530 Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p1NDtrLx3543168; Wed, 23 Feb 2011 19:25:58 +0530 Received: from d28av05.in.ibm.com (loopback [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p1NDrcIs019645; Thu, 24 Feb 2011 00:53:39 +1100 Received: from skywalker.ibm.com ([9.77.68.27]) by d28av05.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id p1NDqS27014791; Thu, 24 Feb 2011 00:53:36 +1100 From: "Aneesh Kumar K.V" To: sfrench@us.ibm.com, agruen@linbit.com, dilger.kernel@dilger.ca, sandeen@redhat.com, tytso@mit.edu, bfields@fieldses.org, jlayton@redhat.com Cc: aneesh.kumar@linux.vnet.ibm.com, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, Andreas Gruenbacher Subject: [PATCH -V5 14/24] richacl: Compute maximum file masks from an acl Date: Wed, 23 Feb 2011 19:22:01 +0530 Message-Id: <1298469131-16555-15-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1298469131-16555-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1298469131-16555-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Wed, 23 Feb 2011 13:56:42 +0000 (UTC) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index 50ba645..69ddb00 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -225,3 +225,131 @@ richace_set_who(struct richace *ace, const char *who) return 0; } EXPORT_SYMBOL_GPL(richace_set_who); + +/** + * richacl_allowed_to_who - mask flags allowed to a specific who value + * + * Computes the mask values allowed to a specific who value, taking + * EVERYONE@ entries into account. + */ +static unsigned int richacl_allowed_to_who(struct richacl *acl, + struct richace *who) +{ + struct richace *ace; + unsigned int allowed = 0; + + richacl_for_each_entry_reverse(ace, acl) { + if (richace_is_inherit_only(ace)) + continue; + if (richace_is_same_identifier(ace, who) || + richace_is_everyone(ace)) { + if (richace_is_allow(ace)) + allowed |= ace->e_mask; + else if (richace_is_deny(ace)) + allowed &= ~ace->e_mask; + } + } + return allowed; +} + +/** + * richacl_group_class_allowed - maximum permissions the group class is allowed + * + * See richacl_compute_max_masks(). + */ +static unsigned int richacl_group_class_allowed(struct richacl *acl) +{ + struct richace *ace; + unsigned int everyone_allowed = 0, group_class_allowed = 0; + int had_group_ace = 0; + + richacl_for_each_entry_reverse(ace, acl) { + if (richace_is_inherit_only(ace) || + richace_is_owner(ace)) + continue; + + if (richace_is_everyone(ace)) { + if (richace_is_allow(ace)) + everyone_allowed |= ace->e_mask; + else if (richace_is_deny(ace)) + everyone_allowed &= ~ace->e_mask; + } else { + group_class_allowed |= + richacl_allowed_to_who(acl, ace); + + if (richace_is_group(ace)) + had_group_ace = 1; + } + } + if (!had_group_ace) + group_class_allowed |= everyone_allowed; + return group_class_allowed; +} + +/** + * richacl_compute_max_masks - compute upper bound masks + * + * Computes upper bound owner, group, and other masks so that none of + * the mask flags allowed by the acl are disabled (for any choice of the + * file owner or group membership). + */ +void richacl_compute_max_masks(struct richacl *acl) +{ + unsigned int gmask = ~0; + struct richace *ace; + + /* + * @gmask contains all permissions which the group class is ever + * allowed. We use it to avoid adding permissions to the group mask + * from everyone@ allow aces which the group class is always denied + * through other aces. For example, the following acl would otherwise + * result in a group mask or rw: + * + * group@:w::deny + * everyone@:rw::allow + * + * Avoid computing @gmask for acls which do not include any group class + * deny aces: in such acls, the group class is never denied any + * permissions from everyone@ allow aces. + */ + +restart: + acl->a_owner_mask = 0; + acl->a_group_mask = 0; + acl->a_other_mask = 0; + + richacl_for_each_entry_reverse(ace, acl) { + if (richace_is_inherit_only(ace)) + continue; + + if (richace_is_owner(ace)) { + if (richace_is_allow(ace)) + acl->a_owner_mask |= ace->e_mask; + else if (richace_is_deny(ace)) + acl->a_owner_mask &= ~ace->e_mask; + } else if (richace_is_everyone(ace)) { + if (richace_is_allow(ace)) { + acl->a_owner_mask |= ace->e_mask; + acl->a_group_mask |= ace->e_mask & gmask; + acl->a_other_mask |= ace->e_mask; + } else if (richace_is_deny(ace)) { + acl->a_owner_mask &= ~ace->e_mask; + acl->a_group_mask &= ~ace->e_mask; + acl->a_other_mask &= ~ace->e_mask; + } + } else { + if (richace_is_allow(ace)) { + acl->a_owner_mask |= ace->e_mask & gmask; + acl->a_group_mask |= ace->e_mask & gmask; + } else if (richace_is_deny(ace) && gmask == ~0) { + gmask = richacl_group_class_allowed(acl); + if (likely(gmask != ~0)) + /* should always be true */ + goto restart; + } + } + } + + acl->a_flags &= ~ACL4_MASKED; +} +EXPORT_SYMBOL_GPL(richacl_compute_max_masks); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index 399dbc9..f491e59 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -287,5 +287,6 @@ extern int richace_set_who(struct richace *, const char *); 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(int); +extern void richacl_compute_max_masks(struct richacl *); #endif /* __RICHACL_H */