Messages in this thread | | | Date | Fri, 25 Feb 2011 18:57:35 +0300 | From | Vasiliy Kulikov <> | Subject | Re: module loading with CAP_NET_ADMIN |
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On Fri, Feb 25, 2011 at 18:29 +0300, Michael Tokarev wrote: > 25.02.2011 15:30, Vasiliy Kulikov wrote: > > On Thu, Feb 24, 2011 at 16:34 +0000, Ben Hutchings wrote: > >> On Thu, 2011-02-24 at 18:12 +0300, Vasiliy Kulikov wrote: > >>> My proposal is changing request_module("%s", name) to something like > >>> request_module("netdev-%s", name) inside of dev_load() and adding > >>> aliases to related drivers. > > It is not the kernel patching which we should worry about, kernel > part is trivial. > > What is not trivial is to patch all the systems out there who > autoloads network drivers based on /etc/modprobe.d/network-aliases.conf > (some local file), ie, numerous working setups which already > uses this mechanism since stone age. And patching these is > not trivial at all, unfortunately. > > Somewhat weird setups (one can load the modules explicitly, and > nowadays this all is handled by udev anyway), but this change > will break some working systems. > > Maybe the cost (some pain for some users) isn't large enough > but the outcome is good, and I think it _is_ good, but it needs > some wider discussion first, imho. > > I can't think of a way to handle this without breaking stuff.
Currently Linux slowly moves in the direction of rootless systems. This definitely need proper restrictions of CAP_* power. Network admin does nothing with general modules. It _has_ to break something one day because old assumptions about permission stuff don't conform CAP_* things: old assumptions are very closely connected with just everything.
I'm not sure how this particular CAP_NET_ADMIN misuse should be fixed, maybe distributions should supply script to upgrade modprobe configs. Also note that change s/CAP_SYS_MODULE/CAP_NET_ADMIN/ was made in 2.6.32, so there is a possibility that the set of affected distributions (that doesn't use udev stuff) is very small.
Thanks for your input,
-- Vasiliy Kulikov http://www.openwall.com - bringing security into open computing environments
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