From: Matt Brown <matt@nmatt.com>
To: James Morris <jmorris@namei.org>
Cc: serge@hallyn.com, gregkh@linuxfoundation.org, jslaby@suse.com,
akpm@linux-foundation.org, jannh@google.com,
keescook@chromium.org, kernel-hardening@lists.openwall.com,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN
Date: Wed, 19 Apr 2017 20:08:02 -0400 [thread overview]
Message-ID: <4a7ab5c3-590e-891f-61ce-534483dc2ec6@nmatt.com> (raw)
In-Reply-To: <alpine.LRH.2.20.1704192114270.12914@namei.org>
On 04/19/2017 07:18 AM, James Morris wrote:
> On Tue, 18 Apr 2017, Matt Brown wrote:
>
>> This patch reproduces GRKERNSEC_HARDEN_TTY functionality from the grsecurity
>> project in-kernel.
>
> It seems like an ugly hack to an ugly feature (CAP_SYS_ADMIN barely makes
> sense here), and rather than sprinkling these types of things throughout
> the kernel, I wonder if it might be better to implement it via LSM, in the
> YAMA module.
>
>
CAP_SYS_ADMIN is already used in the TIOCSTI TTY code to allow
character insertion into TTYs other than the caller's controlling
terminal. This is done because different TTYs indicate a security
boundary that should only be able to be crossed by a privileged
process. This patch would merely extend this security boundary
protection to include unprivileged processes from utilizing a common
TTY to step across a security boundary.
>
> - James
>
prev parent reply other threads:[~2017-04-20 0:08 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-19 3:45 [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN Matt Brown
2017-04-19 4:58 ` Serge E. Hallyn
2017-04-19 5:20 ` Kees Cook
2017-04-19 23:43 ` Matt Brown
2017-04-19 23:21 ` Matt Brown
2017-04-19 23:53 ` Serge E. Hallyn
2017-04-20 4:44 ` Matt Brown
2017-04-20 15:19 ` Serge E. Hallyn
2017-04-20 15:24 ` [kernel-hardening] " Serge E. Hallyn
2017-04-20 17:15 ` matt
2017-04-20 17:41 ` Serge E. Hallyn
2017-04-21 5:09 ` Matt Brown
2017-04-21 5:24 ` Serge E. Hallyn
2017-04-21 6:01 ` Kees Cook
2017-04-22 17:09 ` Matt Brown
2017-04-22 19:50 ` Serge E. Hallyn
2017-04-19 11:18 ` James Morris
2017-04-20 0:08 ` Matt Brown [this message]
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