Re: CAP_SYSLOG, 2.6.38 and user space

[david]

On Fri, 4 Feb 2011, Serge E. Hallyn wrote:

> Quoting Gergely Nagy (algernon@xxxxxxxxxx):
> > On Fri, 2011-02-04 at 16:05 +0000, Serge E. Hallyn wrote:
> > > Quoting Serge E. Hallyn (serge@xxxxxxxxxx):
> > > > > From 2d7408541dd3a6e19a4265b028233789be6a40f4 Mon Sep 17 00:00:00 2001
> > > > From: Serge Hallyn <serge@peq.(none)>
> > > >
> > > > At 2.6.39 or 2.6.40, let's add a sysctl which defaults to 0.  When
> > > > 0, refuse if cap_sys_admin, if 1, then allow.  This will allow
> > > > users to acknowledge (permanently, if they must, using /etc/sysctl.conf)
> > > > that they've seen the syslog message about cap_sys_admin being
> > > > deprecated for syslog.
> > > >
> > > > Signed-off-by: Serge Hallyn <serge@xxxxxxxxxx>
> -			goto warn; /* switch to return -EPERM after 2.6.39 */
> +		     !capable(CAP_SYSLOG)) {
> +			/* remove after 2.6.39 */
> +			if (capable(CAP_SYS_ADMIN))
> +				WARN_ONCE(1, "Attempt to access syslog with CAP_SYS_ADMIN "
> +				  "but no CAP_SYSLOG (deprecated).\n");
> +			else
> +				return -EPERM;
> +		}
> 	}

why does this need to be removed after 2.6.39?

whenever you go to remove it you will break userspace, what's the benifit 
of breaking userspace?

I can understand that it's better to have a syslog daemon with CAP_SYSLOG 
instead of CAP_SYS_ADMIN, but does "it would be better to have userspace 
changed" really translate into "it's so important to have userspace 
changed that we need to break any userspace that hasn't changed"?

I really don't think so.

David Lang
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