From patchwork Fri Jul 30 14:41:15 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 12411387 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5135C4320A for ; Fri, 30 Jul 2021 14:39:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BDBE761050 for ; Fri, 30 Jul 2021 14:39:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239262AbhG3Oji (ORCPT ); Fri, 30 Jul 2021 10:39:38 -0400 Received: from smtp-8fa8.mail.infomaniak.ch ([83.166.143.168]:51673 "EHLO smtp-8fa8.mail.infomaniak.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231286AbhG3Ojf (ORCPT ); Fri, 30 Jul 2021 10:39:35 -0400 Received: from smtp-2-0001.mail.infomaniak.ch (unknown [10.5.36.108]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4GbqmH5tfczMq9DK; Fri, 30 Jul 2021 16:39:27 +0200 (CEST) Received: from localhost (unknown [23.97.221.149]) by smtp-2-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4GbqmH401vzlh8mh; Fri, 30 Jul 2021 16:39:27 +0200 (CEST) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: Alejandro Colomar , Michael Kerrisk Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Jann Horn , Jonathan Corbet , Kees Cook , Randy Dunlap , Vincent Dagonneau , landlock@lists.linux.dev, linux-kernel@vger.kernel.org, linux-man@vger.kernel.org, linux-security-module@vger.kernel.org, =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= Subject: [PATCH v3 3/4] landlock_add_rule.2: Document new syscall Date: Fri, 30 Jul 2021 16:41:15 +0200 Message-Id: <20210730144116.332091-4-mic@digikod.net> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210730144116.332091-1-mic@digikod.net> References: <20210730144116.332091-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: From: Mickaël Salaün This is an adaptation of https://www.kernel.org/doc/html/v5.13/userspace-api/landlock.html Signed-off-by: Mickaël Salaün Link: https://lore.kernel.org/r/20210730144116.332091-4-mic@digikod.net --- Changes since v2: * Fix syscall's rule_attr pointer. * Add an EXAMPLES section referring to landlock(7). * Change list order in the SEE ALSO section. * Fix .IR and .BR use as explained by Alejandro Colomar. Changes since v1: * Replace all ".I" with ".IR", except when used for titles. * Append punctuation to ".IR" and ".BR" when it makes sense (requested by Alejandro Colomar). * Cut lines according to the semantic newline rules (requested by Alejandro Colomar). * Remove roman style from ".TP" section titles (requested by Alejandro Colomar). * Add comma after "i.e." and "e.g.". * Add a "CONFORMING TO" section. * Replace "(2)" with "()" for the described syscall name. --- man2/landlock_add_rule.2 | 144 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 144 insertions(+) create mode 100644 man2/landlock_add_rule.2 diff --git a/man2/landlock_add_rule.2 b/man2/landlock_add_rule.2 new file mode 100644 index 000000000000..eafb8f8201b7 --- /dev/null +++ b/man2/landlock_add_rule.2 @@ -0,0 +1,144 @@ +.\" Copyright © 2017-2020 Mickaël Salaün +.\" Copyright © 2019-2020 ANSSI +.\" Copyright © 2021 Microsoft Corporation +.\" +.\" %%%LICENSE_START(VERBATIM) +.\" Permission is granted to make and distribute verbatim copies of this +.\" manual provided the copyright notice and this permission notice are +.\" preserved on all copies. +.\" +.\" Permission is granted to copy and distribute modified versions of this +.\" manual under the conditions for verbatim copying, provided that the +.\" entire resulting derived work is distributed under the terms of a +.\" permission notice identical to this one. +.\" +.\" Since the Linux kernel and libraries are constantly changing, this +.\" manual page may be incorrect or out-of-date. The author(s) assume no +.\" responsibility for errors or omissions, or for damages resulting from +.\" the use of the information contained herein. The author(s) may not +.\" have taken the same level of care in the production of this manual, +.\" which is licensed free of charge, as they might when working +.\" professionally. +.\" +.\" Formatted or processed versions of this manual, if unaccompanied by +.\" the source, must acknowledge the copyright and authors of this work. +.\" %%%LICENSE_END +.\" +.TH LANDLOCK_ADD_RULE 2 2021-06-27 Linux "Linux Programmer's Manual" +.SH NAME +landlock_add_rule \- add a new Landlock rule to a ruleset +.SH SYNOPSIS +.nf +.BR "#include " " /* Definition of " LANDLOCK_* " constants */" +.BR "#include " " /* Definition of " SYS_* " constants */" +.PP +.BI "int syscall(SYS_landlock_add_rule, int " ruleset_fd , +.BI " enum landlock_rule_type " rule_type , +.BI " const void *" rule_attr ", __u32 " flags ); +.SH DESCRIPTION +A Landlock rule describes an action on an object. +An object is currently a file hierarchy, and the related filesystem actions +are defined with a set of access rights. +This +.BR landlock_add_rule () +system call enables adding a new Landlock rule to an existing ruleset +created with +.BR landlock_create_ruleset (2). +See +.BR landlock (7) +for a global overview. +.PP +.I ruleset_fd +is a Landlock ruleset file descriptor obtained with +.BR landlock_create_ruleset (2). +.PP +.I rule_type +identifies the structure type pointed to by +.IR rule_attr . +Currently, Linux supports the following +.I rule_type +value: +.TP +.B LANDLOCK_RULE_PATH_BENEATH +This defines the object type as a file hierarchy. +In this case, +.I rule_attr +points to the following structure: +.IP +.in +4n +.EX +struct landlock_path_beneath_attr { + __u64 allowed_access; + __s32 parent_fd; +} __attribute__((packed)); +.EE +.in +.IP +.I allowed_access +contains a bitmask of allowed filesystem actions for this file hierarchy +(see +.B Filesystem actions +in +.BR landlock (7)). +.IP +.I parent_fd +is an opened file descriptor, preferably with the +.I O_PATH +flag, +which identifies the parent directory of the file hierarchy or +just a file. +.PP +.I flags +must be 0. +.SH RETURN VALUE +On success, +.BR landlock_add_rule () +returns 0. +.SH ERRORS +.BR landlock_add_rule () +can failed for the following reasons: +.TP +.B EOPNOTSUPP +Landlock is supported by the kernel but disabled at boot time. +.TP +.B EINVAL +.I flags +is not 0, or the rule accesses are inconsistent (i.e., +.I rule_attr->allowed_access +is not a subset of the ruleset handled accesses). +.TP +.B ENOMSG +Empty accesses (i.e., +.I rule_attr->allowed_access +is 0). +.TP +.B EBADF +.I ruleset_fd +is not a file descriptor for the current thread, or a member of +.I rule_attr +is not a file descriptor as expected. +.TP +.B EBADFD +.I ruleset_fd +is not a ruleset file descriptor, or a member of +.I rule_attr +is not the expected file descriptor type. +.TP +.B EPERM +.I ruleset_fd +has no write access to the underlying ruleset. +.TP +.B EFAULT +.I rule_attr +was not a valid address. +.SH VERSIONS +Landlock was added in Linux 5.13. +.SH CONFORMING TO +This system call is Linux-specific. +.SH EXAMPLES +See +.BR landlock (7). +.SH SEE ALSO +.BR landlock_create_ruleset (2), +.BR landlock_restrict_self (2), +.BR landlock (7)