[lxc-devel] [PATCH] Improper pty permissions - missing mode=0620, gid=5

[Serge Hallyn]

Quoting Stéphane Graber (stgraber at ubuntu.com):
> This fix is coming from Debian bug:
> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=720122
> 
> The reason for the hardcoded gid= and mode= is because of the fix for
> CVE-2013-2207 which removes pt_chown from glibc and so requires proper
> write access to devpts.
> 
> It looks like the "tty" group is guaranteed to be gid=5 on at least all
> RedHat based and Debian based systems. So this hardcode gid shouldn't be

Ok.  In the past I've declined to do this precisely bc tty is userspace
specified and therefore I didn't trust this.  But if you've looked into
it this much then I'm happy with it.

> a big problem. If we however support any distro where that's not the
> case, we'll need to implement an extra lxc.conf option and matching
> template changes.
> 
> Signed-off-by: Stéphane Graber <stgraber at ubuntu.com>

Acked-by: Serge E. Hallyn <serge.hallyn at ubuntu.com>

> ---
>  src/lxc/conf.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/src/lxc/conf.c b/src/lxc/conf.c
> index ecbcf41..f3d9aab 100644
> --- a/src/lxc/conf.c
> +++ b/src/lxc/conf.c
> @@ -1426,7 +1426,7 @@ static int setup_pts(int pts)
>  	}
>  
>  	if (mount("devpts", "/dev/pts", "devpts", MS_MGC_VAL,
> -		  "newinstance,ptmxmode=0666")) {
> +		  "newinstance,ptmxmode=0666,mode=0620,gid=5")) {
>  		SYSERROR("failed to mount a new instance of '/dev/pts'");
>  		return -1;
>  	}
> -- 
> 1.8.3.2
> 
> 
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