Re: [PATCH] capabilities/syslog: open code cap_syslog logic to fix build failure

[Kees Cook <kees.cook@canonical.com>]

Hi Serge,

On Thu, Nov 18, 2010 at 08:26:24AM -0600, Serge E. Hallyn wrote:
> Quoting Eric Paris (eparis@redhat.com):
> > @@ -274,7 +274,20 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
> >  	char c;
> >  	int error = 0;
> >  
> > -	error = security_syslog(type, from_file);
> > +	/*
> > +	 * If this is from /proc/kmsg we only do the capabilities checks
> > +	 * at open time.
> > +	 */
> > +	if (type == SYSLOG_ACTION_OPEN || !from_file) {
> > +		if (dmesg_restrict && !capable(CAP_SYS_ADMIN))
> 
> Any chance we could introduce a new capability for this?

Wasn't there talk of creating CAP_SYSLOG or something? Right now most
sysklogd implementations are just starting life as root, so making this
change now shouldn't break anyone.

-Kees

-- 
Kees Cook
Ubuntu Security Team