GNU bug report logs - #24541
runcon tty hijacking via TIOCSTI ioctl

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Message #8 received at 24541 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: up201407890 <at> alunos.dcc.fc.up.pt, 24541 <at> debbugs.gnu.org,
 SE-Linux <SELinux <at> tycho.nsa.gov>
Subject: Re: bug#24541: runcon tty hijacking via TIOCSTI ioctl
Date: Sun, 25 Sep 2016 11:49:40 -0700

[Message part 1 (text/plain, inline)]

up201407890 <at> alunos.dcc.fc.up.pt wrote re <http://bugs.gnu.org/24541>:
> When executing a program via the runcon utility, the nonpriv session
> can escape to the parent session by using the TIOCSTI ioctl to push
> characters into the terminal's input buffer, allowing an attacker to
> execute arbitrary commands without the SELinux security context.

Thanks for the bug report. Surely this is a bug in the setexeccon system call, 
not in the runcon command that uses the system call. That being said, perhaps 
runcon should work around the bug via something like the attached patch.

[runcon.diff (text/x-diff, attachment)]

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