linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Mickaël Salaün" <mic@digikod.net>
To: Alejandro Colomar <alx.manpages@gmail.com>,
	Michael Kerrisk <mtk.manpages@gmail.com>
Cc: "Mickaël Salaün" <mic@digikod.net>,
	"Jann Horn" <jannh@google.com>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Kees Cook" <keescook@chromium.org>,
	"Randy Dunlap" <rdunlap@infradead.org>,
	"Vincent Dagonneau" <vincent.dagonneau@ssi.gouv.fr>,
	landlock@lists.linux.dev, linux-kernel@vger.kernel.org,
	linux-man@vger.kernel.org, linux-security-module@vger.kernel.org,
	"Mickaël Salaün" <mic@linux.microsoft.com>
Subject: [PATCH v3 3/4] landlock_add_rule.2: Document new syscall
Date: Fri, 30 Jul 2021 16:41:15 +0200	[thread overview]
Message-ID: <20210730144116.332091-4-mic@digikod.net> (raw)
In-Reply-To: <20210730144116.332091-1-mic@digikod.net>

From: Mickaël Salaün <mic@linux.microsoft.com>

This is an adaptation of
https://www.kernel.org/doc/html/v5.13/userspace-api/landlock.html

Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
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 <mic@digikod.net>
+.\" 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 <linux/landlock.h>" "  /* Definition of " LANDLOCK_* " constants */"
+.BR "#include <sys/syscall.h>" "     /* 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)
-- 
2.32.0


  parent reply	other threads:[~2021-07-30 14:39 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30 14:41 [PATCH v3 0/4] Add Landlock man pages Mickaël Salaün
2021-07-30 14:41 ` [PATCH v3 1/4] landlock.7: Add a new page to introduce Landlock Mickaël Salaün
2021-07-30 14:41 ` [PATCH v3 2/4] landlock_create_ruleset.2: Document new syscall Mickaël Salaün
2021-07-30 14:41 ` Mickaël Salaün [this message]
2021-07-30 14:41 ` [PATCH v3 4/4] landlock_restrict_self.2: " Mickaël Salaün

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210730144116.332091-4-mic@digikod.net \
    --to=mic@digikod.net \
    --cc=alx.manpages@gmail.com \
    --cc=corbet@lwn.net \
    --cc=jannh@google.com \
    --cc=keescook@chromium.org \
    --cc=landlock@lists.linux.dev \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-man@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=mic@linux.microsoft.com \
    --cc=mtk.manpages@gmail.com \
    --cc=rdunlap@infradead.org \
    --cc=vincent.dagonneau@ssi.gouv.fr \
    --subject='Re: [PATCH v3 3/4] landlock_add_rule.2: Document new syscall' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
on how to clone and mirror all data and code used for this inbox