From: Alexey Gladkov <gladkov.alexey@gmail.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
Linux API <linux-api@vger.kernel.org>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
Linux Security Module <linux-security-module@vger.kernel.org>,
Akinobu Mita <akinobu.mita@gmail.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Alexey Dobriyan <adobriyan@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
Daniel Micay <danielmicay@gmail.com>,
Djalal Harouni <tixxdz@gmail.com>,
"Dmitry V . Levin" <ldv@altlinux.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ingo Molnar <mingo@kernel.org>,
"J . Bruce Fields" <bfields@fieldses.org>,
Jeff Layton <jlayton@poochiereds.net>,
Jonathan Corbet <corbet@lwn.net>,
Kees Cook <keescook@chromium.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
David Howells <dhowells@redhat.com>
Subject: Re: [PATCH v10 8/9] proc: use human-readable values for hidehid
Date: Thu, 9 Apr 2020 16:32:51 +0200 [thread overview]
Message-ID: <20200409143251.pqoprbjnetoup5vw@comp-core-i7-2640m-0182e6> (raw)
In-Reply-To: <87d08pkh4u.fsf@x220.int.ebiederm.org>
On Thu, Apr 02, 2020 at 11:05:21AM -0500, Eric W. Biederman wrote:
> Alexey Gladkov <gladkov.alexey@gmail.com> writes:
>
> > The hidepid parameter values are becoming more and more and it becomes
> > difficult to remember what each new magic number means.
>
> In principle I like this change. In practice I think you have just
> broken ABI compatiblity with the new mount ABI.
>
> In particular the following line seems broken.
>
> > diff --git a/fs/proc/root.c b/fs/proc/root.c
> > index dbcd96f07c7a..ba782d6e6197 100644
> > --- a/fs/proc/root.c
> > +++ b/fs/proc/root.c
> > @@ -45,7 +45,7 @@ enum proc_param {
> >
> > static const struct fs_parameter_spec proc_fs_parameters[] = {
> > fsparam_u32("gid", Opt_gid),
> > - fsparam_u32("hidepid", Opt_hidepid),
> > + fsparam_string("hidepid", Opt_hidepid),
> > fsparam_string("subset", Opt_subset),
> > {}
> > };
>
> As I read fs_parser.c fs_param_is_u32 handles string inputs and turns them
> into numbers, and it handles binary numbers.
Yes, you can use: fsconfig(fsfd, FSCONFIG_SET_BINARY, ...); but in this
case the type of parameter will be fs_value_is_blob [1]. This kind of
parameters is handled by fs_param_is_blob(). The fs_param_is_u32 can
handle only parametes with fs_value_is_string type [2].
Am I missing something?
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/fsopen.c#n405
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/fs_parser.c#n215
> However fs_param_is_string
> appears to only handle strings. It appears to have not capacity to turn
> raw binary numbers into strings.
>
> So I think we probably need to fix fs_param_is_string to raw binary
> numbers before we can safely make this change to fs/proc/root.c
>
> David am I reading the fs_parser.c code correctly? If I am are you ok
> with a change like the above?
>
> Eric
>
--
Rgrds, legion
next prev parent reply other threads:[~2020-04-09 14:33 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-27 17:23 [PATCH v10 0/9] proc: modernize proc to support multiple private instances Alexey Gladkov
2020-03-27 17:23 ` [PATCH v10 1/9] proc: rename struct proc_fs_info to proc_fs_opts Alexey Gladkov
2020-03-27 17:23 ` [PATCH v10 2/9] proc: allow to mount many instances of proc in one pid namespace Alexey Gladkov
2020-04-02 15:31 ` Eric W. Biederman
2020-04-02 16:32 ` Alexey Gladkov
2020-03-27 17:23 ` [PATCH v10 3/9] proc: move hide_pid, pid_gid from pid_namespace to proc_fs_info Alexey Gladkov
2020-03-27 17:23 ` [PATCH v10 4/9] proc: instantiate only pids that we can ptrace on 'hidepid=4' mount option Alexey Gladkov
2020-03-28 20:40 ` Kees Cook
2020-03-28 21:23 ` Alexey Gladkov
2020-03-27 17:23 ` [PATCH v10 5/9] proc: add option to mount only a pids subset Alexey Gladkov
2020-03-27 17:23 ` [PATCH v10 6/9] docs: proc: add documentation for "hidepid=4" and "subset=pid" options and new mount behavior Alexey Gladkov
2020-03-27 17:23 ` [PATCH v10 7/9] proc: move hidepid values to uapi as they are user interface to mount Alexey Gladkov
2020-03-28 20:41 ` Kees Cook
2020-03-28 21:25 ` Alexey Gladkov
2020-03-28 21:53 ` Kees Cook
2020-03-28 23:00 ` Alexey Gladkov
2020-03-29 3:17 ` Kees Cook
2020-04-02 16:58 ` Eric W. Biederman
2020-04-03 23:59 ` Kees Cook
2020-03-27 17:23 ` [PATCH v10 8/9] proc: use human-readable values for hidehid Alexey Gladkov
2020-03-28 20:28 ` Kees Cook
2020-03-28 21:14 ` Alexey Gladkov
2020-03-28 21:52 ` Kees Cook
2020-03-28 22:54 ` Alexey Gladkov
2020-03-30 11:12 ` [PATCH v11 " Alexey Gladkov
2020-03-30 18:33 ` Kees Cook
2020-04-02 16:11 ` Jann Horn
2020-04-02 16:05 ` [PATCH v10 " Eric W. Biederman
2020-04-02 16:51 ` Alexey Gladkov
2020-04-02 17:04 ` Eric W. Biederman
2020-04-09 14:32 ` Alexey Gladkov [this message]
2020-03-27 17:23 ` [PATCH v10 9/9] proc: use named enums for better readability Alexey Gladkov
2020-04-02 17:00 ` [PATCH v10 0/9] proc: modernize proc to support multiple private instances Eric W. Biederman
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=20200409143251.pqoprbjnetoup5vw@comp-core-i7-2640m-0182e6 \
--to=gladkov.alexey@gmail.com \
--cc=adobriyan@gmail.com \
--cc=akinobu.mita@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=bfields@fieldses.org \
--cc=corbet@lwn.net \
--cc=danielmicay@gmail.com \
--cc=dhowells@redhat.com \
--cc=ebiederm@xmission.com \
--cc=gregkh@linuxfoundation.org \
--cc=jlayton@poochiereds.net \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=ldv@altlinux.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mingo@kernel.org \
--cc=oleg@redhat.com \
--cc=tixxdz@gmail.com \
--cc=torvalds@linux-foundation.org \
--cc=viro@zeniv.linux.org.uk \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).