From: Matt Brown <matt@nmatt.com>
To: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc: "Serge E. Hallyn" <serge@hallyn.com>,
Kees Cook <keescook@chromium.org>,
Casey Schaufler <casey@schaufler-ca.com>,
Boris Lukashev <blukashev@sempervictus.com>,
Greg KH <gregkh@linuxfoundation.org>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
linux-security-module <linux-security-module@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI ioctl require CAP_SYS_ADMIN
Date: Sat, 3 Jun 2017 18:22:56 -0400 [thread overview]
Message-ID: <4a8e9445-4c3f-e44e-9d84-fef2ca956517@nmatt.com> (raw)
In-Reply-To: <20170603230048.52b7f111@lxorguk.ukuu.org.uk>
On 06/03/2017 06:00 PM, Alan Cox wrote:
>> TIOCSLCKTRMIOS
>
> That one I'm more dubious about
>
>> TIOCSLTC
>> TIOCSSOFTCAR
>
> tty_io.c also has a few and n_tty has a couple we'd want.
>
>>
>> would it be overkill to have a sysctl kernel.ttyioctlwhitelist.X where X
>> is one of the ioctls above?
>
> Why would anyone want to change the entries on that list
>
Did you see Serge's proposed solution? I want us to not be talking past
each other. Serge proposed the following:
| By default, nothing changes - you can use those on your own tty, need
| CAP_SYS_ADMIN against init_user_ns otherwise.
|
| Introduce a new CAP_TTY_PRIVILEGED.
|
| When may_push_chars is removed from the whitelist, you lose the
| ability to use TIOCSTI on a tty - even your own - if you do not have
| CAP_TTY_PRIVILEGED against the tty's user_ns.
The question is how do you add/remove something from this whitelist? I
assume by add/remove we don't mean that you have to recompile your
kernel to change the whitelist!
you earlier said you wanted the check to look like this:
| if (!whitelisted(ioctl) && different_namespace && magic_flag)
I want to know which namespace you are talking about here. Did you mean
user_namespace? (the namespace I added tracking for in the tty_struct)
WARNING: multiple messages have this Message-ID (diff)
From: matt@nmatt.com (Matt Brown)
To: linux-security-module@vger.kernel.org
Subject: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI ioctl require CAP_SYS_ADMIN
Date: Sat, 3 Jun 2017 18:22:56 -0400 [thread overview]
Message-ID: <4a8e9445-4c3f-e44e-9d84-fef2ca956517@nmatt.com> (raw)
In-Reply-To: <20170603230048.52b7f111@lxorguk.ukuu.org.uk>
On 06/03/2017 06:00 PM, Alan Cox wrote:
>> TIOCSLCKTRMIOS
>
> That one I'm more dubious about
>
>> TIOCSLTC
>> TIOCSSOFTCAR
>
> tty_io.c also has a few and n_tty has a couple we'd want.
>
>>
>> would it be overkill to have a sysctl kernel.ttyioctlwhitelist.X where X
>> is one of the ioctls above?
>
> Why would anyone want to change the entries on that list
>
Did you see Serge's proposed solution? I want us to not be talking past
each other. Serge proposed the following:
| By default, nothing changes - you can use those on your own tty, need
| CAP_SYS_ADMIN against init_user_ns otherwise.
|
| Introduce a new CAP_TTY_PRIVILEGED.
|
| When may_push_chars is removed from the whitelist, you lose the
| ability to use TIOCSTI on a tty - even your own - if you do not have
| CAP_TTY_PRIVILEGED against the tty's user_ns.
The question is how do you add/remove something from this whitelist? I
assume by add/remove we don't mean that you have to recompile your
kernel to change the whitelist!
you earlier said you wanted the check to look like this:
| if (!whitelisted(ioctl) && different_namespace && magic_flag)
I want to know which namespace you are talking about here. Did you mean
user_namespace? (the namespace I added tracking for in the tty_struct)
--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2017-06-03 22:24 UTC|newest]
Thread overview: 132+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-29 21:37 [PATCH v7 0/2] security: tty: make TIOCSTI ioctl require CAP_SYS_ADMIN Matt Brown
2017-05-29 21:37 ` [kernel-hardening] " Matt Brown
2017-05-29 21:37 ` Matt Brown
2017-05-29 21:37 ` [PATCH v7 1/2] security: tty: Add owner user namespace to tty_struct Matt Brown
2017-05-29 21:37 ` [kernel-hardening] " Matt Brown
2017-05-29 21:37 ` Matt Brown
2017-05-29 21:38 ` [PATCH v7 2/2] security: tty: make TIOCSTI ioctl require CAP_SYS_ADMIN Matt Brown
2017-05-29 21:38 ` [kernel-hardening] " Matt Brown
2017-05-29 21:38 ` Matt Brown
2017-05-29 22:26 ` Alan Cox
2017-05-29 22:26 ` [kernel-hardening] " Alan Cox
2017-05-29 22:26 ` Alan Cox
2017-05-29 23:51 ` [kernel-hardening] " Boris Lukashev
2017-05-29 23:51 ` Boris Lukashev
2017-05-30 0:27 ` Casey Schaufler
2017-05-30 0:27 ` Casey Schaufler
2017-05-30 2:00 ` Matt Brown
2017-05-30 2:00 ` Matt Brown
2017-05-30 2:46 ` Casey Schaufler
2017-05-30 2:46 ` Casey Schaufler
2017-05-30 3:18 ` Matt Brown
2017-05-30 3:18 ` Matt Brown
2017-05-30 12:24 ` Alan Cox
2017-05-30 12:24 ` Alan Cox
2017-05-30 16:28 ` Matt Brown
2017-05-30 16:28 ` Matt Brown
2017-05-30 16:44 ` Daniel Micay
2017-05-30 16:44 ` Daniel Micay
2017-05-30 18:32 ` Stephen Smalley
2017-05-30 18:32 ` Stephen Smalley
2017-05-30 18:44 ` Nick Kralevich
2017-05-30 18:44 ` Nick Kralevich
2017-05-30 18:57 ` Matt Brown
2017-05-30 18:57 ` Matt Brown
2017-05-30 20:22 ` Daniel Micay
2017-05-30 20:22 ` Daniel Micay
2017-05-30 23:00 ` Matt Brown
2017-05-30 23:00 ` Matt Brown
2017-05-30 23:40 ` Daniel Micay
2017-05-30 23:40 ` Daniel Micay
2017-05-30 23:59 ` Matt Brown
2017-05-30 23:59 ` Matt Brown
2017-05-30 22:51 ` Alan Cox
2017-05-30 22:51 ` Alan Cox
2017-05-30 23:19 ` Matt Brown
2017-05-30 23:19 ` Matt Brown
2017-05-30 23:56 ` Alan Cox
2017-05-30 23:56 ` Alan Cox
2017-06-01 2:35 ` Kees Cook
2017-06-01 2:35 ` Kees Cook
2017-06-01 2:35 ` Kees Cook
2017-06-01 7:12 ` lazytyped
2017-06-01 18:46 ` Kees Cook
2017-06-01 22:56 ` James Morris
2017-06-02 18:46 ` Kees Cook
2017-06-01 13:08 ` Alan Cox
2017-06-01 13:08 ` Alan Cox
2017-06-01 13:08 ` Alan Cox
2017-06-01 17:18 ` Serge E. Hallyn
2017-06-01 17:18 ` Serge E. Hallyn
2017-06-01 17:18 ` Serge E. Hallyn
2017-06-01 21:26 ` Alan Cox
2017-06-01 21:26 ` Alan Cox
2017-06-01 21:26 ` Alan Cox
2017-06-01 18:58 ` Kees Cook
2017-06-01 18:58 ` Kees Cook
2017-06-01 18:58 ` Kees Cook
2017-06-01 21:24 ` Alan Cox
2017-06-01 21:24 ` Alan Cox
2017-06-01 21:24 ` Alan Cox
2017-06-02 14:46 ` Matt Brown
2017-06-02 14:46 ` Matt Brown
2017-06-02 14:46 ` Matt Brown
2017-06-02 15:36 ` Serge E. Hallyn
2017-06-02 15:36 ` Serge E. Hallyn
2017-06-02 15:36 ` Serge E. Hallyn
2017-06-02 16:02 ` Matt Brown
2017-06-02 16:02 ` Matt Brown
2017-06-02 16:02 ` Matt Brown
2017-06-02 16:57 ` Serge E. Hallyn
2017-06-02 16:57 ` Serge E. Hallyn
2017-06-02 16:57 ` Serge E. Hallyn
2017-06-02 16:57 ` Serge E. Hallyn
2017-06-02 17:32 ` Matt Brown
2017-06-02 17:32 ` Matt Brown
2017-06-02 17:32 ` Matt Brown
2017-06-02 18:18 ` Serge E. Hallyn
2017-06-02 18:18 ` Serge E. Hallyn
2017-06-02 18:18 ` Serge E. Hallyn
2017-06-02 18:18 ` Serge E. Hallyn
2017-06-02 19:22 ` Matt Brown
2017-06-02 19:22 ` Matt Brown
2017-06-02 19:22 ` Matt Brown
2017-06-02 19:25 ` Kees Cook
2017-06-02 19:25 ` Kees Cook
2017-06-02 19:25 ` Kees Cook
2017-06-02 19:25 ` Kees Cook
2017-06-02 19:26 ` Matt Brown
2017-06-02 19:26 ` Matt Brown
2017-06-02 19:26 ` Matt Brown
2017-06-02 19:26 ` Matt Brown
2017-06-02 20:05 ` Alan Cox
2017-06-02 20:05 ` Alan Cox
2017-06-02 20:05 ` Alan Cox
2017-06-02 20:11 ` Nick Kralevich
2017-06-02 20:11 ` Nick Kralevich
2017-06-02 20:11 ` Nick Kralevich
2017-06-02 20:46 ` Matt Brown
2017-06-02 20:46 ` Matt Brown
2017-06-02 20:46 ` Matt Brown
2017-06-03 22:00 ` Alan Cox
2017-06-03 22:00 ` Alan Cox
2017-06-03 22:00 ` Alan Cox
2017-06-03 22:22 ` Matt Brown [this message]
2017-06-03 22:22 ` Matt Brown
2017-06-03 22:22 ` Matt Brown
2017-06-04 3:37 ` Peter Dolding
2017-06-04 3:37 ` Peter Dolding
2017-06-04 3:37 ` Peter Dolding
2017-05-30 15:20 ` Casey Schaufler
2017-05-30 15:20 ` Casey Schaufler
2017-05-30 16:09 ` Matt Brown
2017-05-30 16:09 ` Matt Brown
2017-06-04 6:29 ` Boris Lukashev
2017-06-04 6:29 ` Boris Lukashev
2017-05-31 2:48 ` James Morris
2017-05-31 2:48 ` James Morris
2017-05-31 4:10 ` Matt Brown
2017-05-31 4:10 ` Matt Brown
2017-05-30 0:15 ` Matt Brown
2017-05-30 0:15 ` [kernel-hardening] " Matt Brown
2017-05-30 0:15 ` Matt Brown
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=4a8e9445-4c3f-e44e-9d84-fef2ca956517@nmatt.com \
--to=matt@nmatt.com \
--cc=blukashev@sempervictus.com \
--cc=casey@schaufler-ca.com \
--cc=gnomes@lxorguk.ukuu.org.uk \
--cc=gregkh@linuxfoundation.org \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=serge@hallyn.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.