Messages in this thread | | | Subject | Re: [PATCH] don't allow CAP_NET_ADMIN to load non-netdev kernel modules | From | Ben Hutchings <> | Date | Fri, 25 Feb 2011 19:53:05 +0000 |
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On Fri, 2011-02-25 at 11:43 -0800, David Miller wrote: > From: Ben Hutchings <bhutchings@solarflare.com> > Date: Fri, 25 Feb 2011 19:30:16 +0000 > > > On Fri, 2011-02-25 at 11:16 -0800, David Miller wrote: > >> From: Ben Hutchings <bhutchings@solarflare.com> > >> Date: Fri, 25 Feb 2011 19:07:59 +0000 > >> > >> > You realise that module loading doesn't actually run in the context of > >> > request_module(), right? > >> > >> Why is that a barrier? We could simply pass a capability mask into > >> request_module if necessary. > >> > >> It's an implementation detail, and not a deterrant to my suggested > >> scheme. > > > > It's not an implementation detail. modprobe currently runs with full > > capabilities; your proposal requires its capabilities to be limited to > > those of the capabilities of the process that triggered the > > request_module() (plus, presumably, CAP_SYS_MODULE). > > The idea was that the kernel will be the entity that will inspect the > elf sections and validate the capability bits, not the userspace > module loader.
Yes, I understand that.
> Surely we if we can pass an arbitrary string out to the loading > process as part of the module loading context, we can pass along > capability bits as well.
If you want insert_module() to be able to deny loading some modules based on the capabilities of the process calling request_module() then you either have to *reduce* the capabilities given to modprobe or create some extra process state, separate from the usual capability state, specifically for this purpose.
Ben.
-- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.
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