From patchwork Wed Jul 22 13:02:57 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: 6843891 Return-Path: X-Original-To: patchwork-linux-nfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 1C619C05AC for ; Wed, 22 Jul 2015 13:23:39 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 1E452206DB for ; Wed, 22 Jul 2015 13:23:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F26D520544 for ; Wed, 22 Jul 2015 13:23:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965198AbbGVNXQ (ORCPT ); Wed, 22 Jul 2015 09:23:16 -0400 Received: from mail-wi0-f169.google.com ([209.85.212.169]:37360 "EHLO mail-wi0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755276AbbGVNEM (ORCPT ); Wed, 22 Jul 2015 09:04:12 -0400 Received: by wibud3 with SMTP id ud3so171479178wib.0; Wed, 22 Jul 2015 06:04:10 -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=mNgETksEOnsoEjrJc77CtTCO/+SBRJyGNd8+BkERKZY=; b=bYC+W2HGE5H8xG0R/WxMzYKZQQCJXkwqxWP03iCpGJWPkBwZE9GbUSHVfnvlQ3vo17 Z9wtY7B78KZ+GxOdDDVu8l0PE8vJfAAwzuXDJyHydYfqSx+/R2KgHXFXz4bgzvun0S7I 8md2rqhlH7Zty1ncgxRYvR0AbkoXZkvStbXyWyAGC6AuB4EoUAh9tLXKMhDvI5+r4pSf pD7wWEMK6DEmzB8tYDb3xu73K49G9bKgHp6VHp/ujN3EKruBeukCV+hkphigBW8bvFwz zssfiZjOWkPw1xkAHDAuhx+Pv5yaYsbMCcuqMOf9Djgv7BQtYXcytyprSj2LX7G87TJ9 dh6g== X-Received: by 10.180.8.234 with SMTP id u10mr37408612wia.4.1437570250791; Wed, 22 Jul 2015 06:04:10 -0700 (PDT) Received: from schleppi.home.com ([149.14.88.26]) by smtp.gmail.com with ESMTPSA id u7sm21992628wif.3.2015.07.22.06.04.07 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 Jul 2015 06:04:09 -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 07/39] richacl: Permission mapping functions Date: Wed, 22 Jul 2015 15:02:57 +0200 Message-Id: <1437570209-29832-8-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-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@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 We need to map from POSIX permissions to NFSv4 permissions when a chmod() is done, from NFSv4 permissions to POSIX permissions when an acl is set (which implicitly sets the file permission bits), and from the MAY_READ/MAY_WRITE/MAY_EXEC/MAY_APPEND flags to NFSv4 permissions when doing an access check in a richacl. Signed-off-by: Andreas Gruenbacher --- fs/richacl_base.c | 113 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/richacl.h | 47 +++++++++++++++++++- 2 files changed, 159 insertions(+), 1 deletion(-) diff --git a/fs/richacl_base.c b/fs/richacl_base.c index 6d9a073..d12f984 100644 --- a/fs/richacl_base.c +++ b/fs/richacl_base.c @@ -65,3 +65,116 @@ richace_copy(struct richace *to, const struct richace *from) { memcpy(to, from, sizeof(struct richace)); } + +/* + * richacl_mask_to_mode - compute the file permission bits which correspond to @mask + * @mask: %RICHACE_* permission mask + * + * See richacl_masks_to_mode(). + */ +static int +richacl_mask_to_mode(unsigned int mask) +{ + int mode = 0; + + if (mask & RICHACE_POSIX_MODE_READ) + mode |= S_IROTH; + if (mask & RICHACE_POSIX_MODE_WRITE) + mode |= S_IWOTH; + if (mask & RICHACE_POSIX_MODE_EXEC) + mode |= S_IXOTH; + + return mode; +} + +/** + * richacl_masks_to_mode - compute the file permission bits from the file masks + * + * When setting a richacl, we set the file permission bits to indicate maximum + * permissions: for example, we set the Write permission when a mask contains + * RICHACE_APPEND_DATA even if it does not also contain RICHACE_WRITE_DATA. + * + * Permissions which are not in RICHACE_POSIX_MODE_READ, RICHACE_POSIX_MODE_WRITE, or + * RICHACE_POSIX_MODE_EXEC cannot be represented in the file permission bits. + * Such permissions can still be effective, but not for new files or after a + * chmod(); they must be explicitly enabled in the richacl. + */ +int +richacl_masks_to_mode(const struct richacl *acl) +{ + return richacl_mask_to_mode(acl->a_owner_mask) << 6 | + richacl_mask_to_mode(acl->a_group_mask) << 3 | + richacl_mask_to_mode(acl->a_other_mask); +} +EXPORT_SYMBOL_GPL(richacl_masks_to_mode); + +/** + * richacl_mode_to_mask - compute a file mask from the lowest three mode bits + * + * When the file permission bits of a file are set with chmod(), this specifies + * the maximum permissions that processes will get. All permissions beyond + * that will be removed from the file masks, and become ineffective. + */ +unsigned int +richacl_mode_to_mask(mode_t mode) +{ + unsigned int mask = 0; + + if (mode & S_IROTH) + mask |= RICHACE_POSIX_MODE_READ; + if (mode & S_IWOTH) + mask |= RICHACE_POSIX_MODE_WRITE; + if (mode & S_IXOTH) + mask |= RICHACE_POSIX_MODE_EXEC; + + return mask; +} + +/** + * richacl_want_to_mask - convert the iop->permission want argument to a mask + * @want: @want argument of the permission inode operation + * + * When checking for append, @want is (MAY_WRITE | MAY_APPEND). + * + * Richacls use the iop->may_create and iop->may_delete hooks which are + * used for checking if creating and deleting files is allowed. These hooks do + * not use richacl_want_to_mask(), so we do not have to deal with mapping + * MAY_WRITE to RICHACE_ADD_FILE, RICHACE_ADD_SUBDIRECTORY, and RICHACE_DELETE_CHILD + * here. + */ +unsigned int +richacl_want_to_mask(unsigned int want) +{ + unsigned int mask = 0; + + if (want & MAY_READ) + mask |= RICHACE_READ_DATA; + if (want & MAY_DELETE_SELF) + mask |= RICHACE_DELETE; + if (want & MAY_TAKE_OWNERSHIP) + mask |= RICHACE_WRITE_OWNER; + if (want & MAY_CHMOD) + mask |= RICHACE_WRITE_ACL; + if (want & MAY_SET_TIMES) + mask |= RICHACE_WRITE_ATTRIBUTES; + if (want & MAY_EXEC) + mask |= RICHACE_EXECUTE; + /* + * differentiate MAY_WRITE from these request + */ + if (want & (MAY_APPEND | + MAY_CREATE_FILE | MAY_CREATE_DIR | + MAY_DELETE_CHILD)) { + if (want & MAY_APPEND) + mask |= RICHACE_APPEND_DATA; + if (want & MAY_CREATE_FILE) + mask |= RICHACE_ADD_FILE; + if (want & MAY_CREATE_DIR) + mask |= RICHACE_ADD_SUBDIRECTORY; + if (want & MAY_DELETE_CHILD) + mask |= RICHACE_DELETE_CHILD; + } else if (want & MAY_WRITE) + mask |= RICHACE_WRITE_DATA; + return mask; +} +EXPORT_SYMBOL_GPL(richacl_want_to_mask); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index 060d5e4..1ae0bf8 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -118,6 +118,49 @@ struct richacl { RICHACE_WRITE_OWNER | \ RICHACE_SYNCHRONIZE) +/* + * The POSIX permissions are supersets of the following NFSv4 permissions: + * + * - MAY_READ maps to READ_DATA or LIST_DIRECTORY, depending on the type + * of the file system object. + * + * - MAY_WRITE maps to WRITE_DATA or RICHACE_APPEND_DATA for files, and to + * ADD_FILE, RICHACE_ADD_SUBDIRECTORY, or RICHACE_DELETE_CHILD for directories. + * + * - MAY_EXECUTE maps to RICHACE_EXECUTE. + * + * (Some of these NFSv4 permissions have the same bit values.) + */ +#define RICHACE_POSIX_MODE_READ ( \ + RICHACE_READ_DATA | \ + RICHACE_LIST_DIRECTORY) +#define RICHACE_POSIX_MODE_WRITE ( \ + RICHACE_WRITE_DATA | \ + RICHACE_ADD_FILE | \ + RICHACE_APPEND_DATA | \ + RICHACE_ADD_SUBDIRECTORY | \ + RICHACE_DELETE_CHILD) +#define RICHACE_POSIX_MODE_EXEC RICHACE_EXECUTE +#define RICHACE_POSIX_MODE_ALL ( \ + RICHACE_POSIX_MODE_READ | \ + RICHACE_POSIX_MODE_WRITE | \ + RICHACE_POSIX_MODE_EXEC) +/* + * These permissions are always allowed + * no matter what the acl says. + */ +#define RICHACE_POSIX_ALWAYS_ALLOWED ( \ + RICHACE_SYNCHRONIZE | \ + RICHACE_READ_ATTRIBUTES | \ + RICHACE_READ_ACL) +/* + * The owner is implicitly granted + * these permissions under POSIX. + */ +#define RICHACE_POSIX_OWNER_ALLOWED ( \ + RICHACE_WRITE_ATTRIBUTES | \ + RICHACE_WRITE_OWNER | \ + RICHACE_WRITE_ACL) /** * richacl_get - grab another reference to a richacl handle */ @@ -255,6 +298,8 @@ richace_is_same_identifier(const struct richace *a, const struct richace *b) extern struct richacl *richacl_alloc(int, gfp_t); extern struct richacl *richacl_clone(const struct richacl *, gfp_t); extern void richace_copy(struct richace *, const struct richace *); - +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); #endif /* __RICHACL_H */