linux-kernel - Re: [PATCH v2 02/11] mount_setattr.2: move mount_attr struct to mount

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <2025-08-07.1754570250-rented-dazzler-furry-proton-robust-diamonds-Kgpe2w@cyphar.com>
Date: Thu, 7 Aug 2025 22:38:36 +1000
From: Aleksa Sarai <cyphar@...har.com>
To: Alejandro Colomar <alx@...nel.org>
Cc: "Michael T. Kerrisk" <mtk.manpages@...il.com>, 
	Alexander Viro <viro@...iv.linux.org.uk>, Jan Kara <jack@...e.cz>, Askar Safin <safinaskar@...omail.com>, 
	"G. Branden Robinson" <g.branden.robinson@...il.com>, linux-man@...r.kernel.org, linux-api@...r.kernel.org, 
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, 
	David Howells <dhowells@...hat.com>, Christian Brauner <brauner@...nel.org>
Subject: Re: [PATCH v2 02/11] mount_setattr.2: move mount_attr struct to
 mount_attr.2type

On 2025-08-07, Alejandro Colomar <alx@...nel.org> wrote:
> Hi Aleksa,
> 
> On Thu, Aug 07, 2025 at 03:44:36AM +1000, Aleksa Sarai wrote:
> > As with open_how(2type), it makes sense to move this to a separate man
> > page.  In addition, future man pages added in this patchset will want to
> > reference mount_attr(2type).
> > 
> > Signed-off-by: Aleksa Sarai <cyphar@...har.com>
> > ---
> >  man/man2/mount_setattr.2      | 17 ++++---------
> >  man/man2type/mount_attr.2type | 58 +++++++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 63 insertions(+), 12 deletions(-)
> > 
> > diff --git a/man/man2/mount_setattr.2 b/man/man2/mount_setattr.2
> > index c96f0657f046..d44fafc93a20 100644
> > --- a/man/man2/mount_setattr.2
> > +++ b/man/man2/mount_setattr.2
> > @@ -114,18 +114,11 @@ .SH DESCRIPTION
> >  .I attr
> >  argument of
> >  .BR mount_setattr ()
> > -is a structure of the following form:
> > -.P
> > -.in +4n
> > -.EX
> > -struct mount_attr {
> > -    __u64 attr_set;     /* Mount properties to set */
> > -    __u64 attr_clr;     /* Mount properties to clear */
> > -    __u64 propagation;  /* Mount propagation type */
> > -    __u64 userns_fd;    /* User namespace file descriptor */
> > -};
> > -.EE
> > -.in
> > +is a pointer to a
> > +.I mount_attr
> > +structure,
> > +described in
> > +.BR mount_attr (2type).
> >  .P
> >  The
> >  .I attr_set
> > diff --git a/man/man2type/mount_attr.2type b/man/man2type/mount_attr.2type
> > new file mode 100644
> > index 000000000000..b7a3ace6b3b9
> > --- /dev/null
> > +++ b/man/man2type/mount_attr.2type
> > @@ -0,0 +1,58 @@
> > +
> 
> Please remove this blank.  It is not diagnosed by groff(1), but I think
> it should be diagnosed (blank lines are diagnosed elsewhere).  I've
> reported a bug to groff(1) (Branden will be reading this, anyway).
> 
> > +.\" Copyright, the authors of the Linux man-pages project
> > +.\"
> > +.\" SPDX-License-Identifier: Linux-man-pages-copyleft
> > +.\"
> > +.TH mount_attr 2type (date) "Linux man-pages (unreleased)"
> > +.SH NAME
> > +mount_attr \- what mount properties to set and clear
> > +.SH LIBRARY
> > +Linux kernel headers
> > +.SH SYNOPSIS
> > +.EX
> > +.B #include <sys/mount.h>
> > +.P
> > +.B struct mount_attr {
> > +.BR "    __u64 attr_set;" "     /* Mount properties to set */"
> > +.BR "    __u64 attr_clr;" "     /* Mount properties to clear */"
> > +.BR "    __u64 propagation;" "  /* Mount propagation type */"
> > +.BR "    __u64 userns_fd;" "    /* User namespace file descriptor */"
> > +    /* ... */
> > +.B };
> > +.EE
> > +.SH DESCRIPTION
> > +Specifies which mount properties should be changed with
> > +.BR mount_setattr (2).
> > +.P
> > +The fields are as follows:
> > +.TP
> > +.I .attr_set
> > +This field specifies which
> > +.BI MOUNT_ATTR_ *
> > +attribute flags to set.
> > +.TP
> > +.I .attr_clr
> > +This fields specifies which
> > +.BI MOUNT_ATTR_ *
> > +attribute flags to clear.
> > +.TP
> > +.I .propagation
> > +This field specifies what mount propagation will be applied.
> > +The valid values of this field are the same propagation types described in
> > +.BR mount_namespaces (7).
> > +.TP
> > +.I .userns_fd
> > +This fields specifies a file descriptor that indicates which user namespace to
> 
> s/fields/field/
> 
> > +use as a reference for ID-mapped mounts with
> > +.BR MOUNT_ATTR_IDMAP .
> > +.SH VERSIONS
> > +Extra fields may be appended to the structure,
> > +with a zero value in a new field resulting in
> > +the kernel behaving as though that extension field was not present.
> > +Therefore, a user
> > +.I must
> > +zero-fill this structure on initialization.
> 
> I think this would be more appropriate for HISTORY.  In VERSIONS, we
> usually document differences with the BSDs or other systems.
> 
> While moving this to HISTORY, it would also be useful to mention the
> glibc version that added the structure.  In the future, we'd document
> the versions of glibc and Linux that have added members.

Sure, though I just copied this section from open_how(2type).

> > +.SH STANDARDS
> > +Linux.
> > +.SH SEE ALSO
> > +.BR mount_setattr (2)
> 
> Have a lovely day!
> Alex
> 
> -- 
> <https://www.alejandro-colomar.es/>



-- 
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
https://www.cyphar.com/

Download attachment "signature.asc" of type "application/pgp-signature" (229 bytes)