On Mon, Feb 28, 2011 at 12:29 +0300, Michael Tokarev wrote:

27.02.2011 23:22, Arnd Bergmann wrote:

quoted

The backwards compatibility should mostly be for systems that today don't
use split capabilities, right?

The fallback could therefore rely on CAP_SYS_MODULE as well:

	if (request_module("netdev-%s", name)) {
		if (capable(CAP_SYS_MODULE))
			request_module("%s", name);
	}

Not 100% solution, but should solve the capability escalation nicely without
causing much pain.

To me this looks like the best solution so far - trivial and
compatible.

Agreed, it's looks good.  But before the request_module() there is a check
for capabile(CAP_NET_ADMIN), IMO it's better to request either
CAP_NET_ADMIN or CAP_SYS_MODULE, not both of them.

	if (!dev) {
        if (capable(CAP_NET_ADMIN))
            request_module("netdev-%s", name))
        if (capable(CAP_SYS_MODULE) {
            if (!request_module("%s", name))
                WARN_ONE(1, "Loading kernel module for a network device"
" with CAP_SYS_MODULE (deprecated).  Use CAP_NET_ADMIN and alias"
" netdev-%s instead\n", name);
        }
    }

The only drawback is distributions/setups that already use
CAP_SYS_MODULE'less network scripts.

David, are you OK with this way?


Thanks,

-- 
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments