From: Andrew Morton <akpm@linux-foundation.org>
To: Frank Benkstein <frank-lkml@benkstein.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: VT_PROCESS, VT_LOCKSWITCH capabilities
Date: Tue, 31 Jul 2007 21:49:31 -0700 [thread overview]
Message-ID: <20070731214931.8d05f367.akpm@linux-foundation.org> (raw)
In-Reply-To: <46AFB62E.2080303@benkstein.net>
On Wed, 01 Aug 2007 00:22:38 +0200 Frank Benkstein <frank-lkml@benkstein.net> wrote:
> I wonder why there are different permissions needed for VT_PROCESS
> (access to the current virtual console) and VT_LOCKSWITCH
> (CAP_SYS_TTY_CONFIG).
>
> The first one lets the calling process decide if console switching is
> allowed, the second one simply disables it. If a program wants to
> forbid console switching the only technical difference I can see is that
> switching is automatically reenabled when the program exits when using
> VT_PROCESS. When using VT_LOCKSWITCH it must be manually reenabled.
> When the program uses the first method and disables terminal signals and
> SysRQ is disabled, too, I see no practical difference between the two.
It'd take some kernel archaeology to work out how things got the way they
are.
Perhaps the issue with VT_LOCKSWITCH is that its effects will persist after
the user has logged out? So user A is effectively altering user B's
console, hence suitable capabilities are needed?
Is the current code actually causing any observable problem?
next prev parent reply other threads:[~2007-08-01 4:49 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-31 22:22 VT_PROCESS, VT_LOCKSWITCH capabilities Frank Benkstein
2007-08-01 2:44 ` Frank Benkstein
2007-08-01 22:19 ` Andrew Morton
2007-08-02 10:31 ` Frank Benkstein
2007-08-01 4:49 ` Andrew Morton [this message]
2007-08-01 9:53 ` Frank Benkstein
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