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From: Daniel Micay <danielmicay@gmail.com>
To: Matt Brown <matt@nmatt.com>, Nick Kralevich <nnk@google.com>,
	Stephen Smalley <sds@tycho.nsa.gov>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
	Casey Schaufler <casey@schaufler-ca.com>,
	Boris Lukashev <blukashev@sempervictus.com>,
	Greg KH <gregkh@linuxfoundation.org>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	Kees Cook <keescook@chromium.org>,
	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: Tue, 30 May 2017 16:22:37 -0400	[thread overview]
Message-ID: <1496175757.9871.6.camel@gmail.com> (raw)
In-Reply-To: <100b7d8c-7468-3122-4f59-3b0dcdf5dfc3@nmatt.com>

> Thanks, I didn't know that android was doing this. I still think this
> feature
> is worthwhile for people to be able to harden their systems against
> this attack
> vector without having to implement a MAC.

Since there's a capable LSM hook for ioctl already, it means it could go
in Yama with ptrace_scope but core kernel code would still need to be
changed to track the owning tty. I think Yama vs. core kernel shouldn't
matter much anymore due to stackable LSMs.

Not the case for perf_event_paranoid=3 where a) there's already a sysctl
exposed which would be unfortunate to duplicate, b) there isn't an LSM
hook yet (AFAIK).

The toggles for ptrace and perf events are more useful though since
they're very commonly used debugging features vs. this obscure, rarely
used ioctl that in practice no one will notice is missing. It's still
friendlier to have a toggle than a seccomp policy requiring a reboot to
get rid of it, or worse compiling it out of the kernel.

  reply	other threads:[~2017-05-30 20:22 UTC|newest]

Thread overview: 49+ 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 ` [PATCH v7 1/2] security: tty: Add owner user namespace to tty_struct 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 22:26   ` Alan Cox
2017-05-29 23:51     ` [kernel-hardening] " Boris Lukashev
2017-05-30  0:27       ` Casey Schaufler
2017-05-30  2:00         ` Matt Brown
2017-05-30  2:46           ` Casey Schaufler
2017-05-30  3:18             ` Matt Brown
2017-05-30 12:24               ` Alan Cox
2017-05-30 16:28                 ` Matt Brown
2017-05-30 16:44                   ` Daniel Micay
2017-05-30 18:32                   ` Stephen Smalley
2017-05-30 18:44                     ` Nick Kralevich
2017-05-30 18:57                       ` Matt Brown
2017-05-30 20:22                         ` Daniel Micay [this message]
2017-05-30 23:00                           ` Matt Brown
2017-05-30 23:40                             ` Daniel Micay
2017-05-30 23:59                               ` Matt Brown
2017-05-30 22:51                   ` Alan Cox
2017-05-30 23:19                     ` Matt Brown
2017-05-30 23:56                       ` Alan Cox
2017-06-01  2:35                         ` Kees Cook
2017-06-01 13:08                           ` Alan Cox
2017-06-01 17:18                             ` Serge E. Hallyn
2017-06-01 21:26                               ` Alan Cox
2017-06-01 18:58                             ` Kees Cook
2017-06-01 21:24                               ` Alan Cox
2017-06-02 14:46                                 ` Matt Brown
2017-06-02 15:36                                   ` Serge E. Hallyn
2017-06-02 16:02                                     ` Matt Brown
2017-06-02 16:57                                       ` Serge E. Hallyn
2017-06-02 17:32                                         ` Matt Brown
2017-06-02 18:18                                           ` Serge E. Hallyn
2017-06-02 19:22                                             ` Matt Brown
2017-06-02 19:25                                               ` Kees Cook
2017-06-02 19:26                                                 ` Matt Brown
2017-06-02 20:05                                       ` Alan Cox
2017-06-02 20:11                                         ` Nick Kralevich
2017-06-02 20:46                                         ` Matt Brown
2017-06-03 22:00                                           ` Alan Cox
2017-06-03 22:22                                             ` Matt Brown
2017-06-04  3:37                                               ` Peter Dolding
2017-05-30 15:20               ` Casey Schaufler
2017-05-30 16:09                 ` Matt Brown
2017-06-04  6:29         ` Boris Lukashev
2017-05-31  2:48       ` James Morris
2017-05-31  4:10         ` Matt Brown
2017-05-30  0:15     ` Matt Brown

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