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From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To: Matt Brown <matt@nmatt.com>
Cc: 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: Wed, 31 May 2017 00:56:33 +0100	[thread overview]
Message-ID: <20170531005633.484a2e14@alans-desktop> (raw)
In-Reply-To: <3bd4ff7b-6f7d-52b0-03f6-026bac79f11f@nmatt.com>

> This is my point. Apps will continue to shoot themselves in the foot. Of course
> the correct response to one of these vulns is to not pass ttys across a
> security boundary. We have an opportunity here to reduce the impact of this bug
> class at the kernel level. 

Not really.

If you pass me your console for example I can mmap your framebuffer and
spy on you all day. Or I could reprogram your fonts, your keyboard, your
video mode, or use set and paste selection to write stuff. If you are
using X and you can't get tty handles right you'll no doubt pass me a
copy of your X file descriptor in which case I own your display, your
keyboard and your mouse and I don't need to use TIOCSTI there either.

There are so many different attacks based upon that screwup that the
kernel cannot defend against them. You aren't exactly reducing the impact.

Alan

  reply	other threads:[~2017-05-30 23:56 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
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 [this message]
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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