Messages in this thread | | | Date | Thu, 18 Oct 2012 08:11:54 -0400 | From | Josh Boyer <> | Subject | Re: RFC: sign the modules at install time |
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On Thu, Oct 18, 2012 at 03:01:08PM +1030, Rusty Russell wrote: > Linus Torvalds <torvalds@linux-foundation.org> writes: > > On Wed, Oct 17, 2012 at 3:19 PM, David Howells <dhowells@redhat.com> wrote: > >> > >> It's probably even better to just get rid of all the automatic module signing > >> stuff completely and leave the sign-file script for the builder to use > >> manually. The module verification code will still be present. > > > > That's just disgusting crazy talk. > > > > Christ, David, get a grip on yourself. You seem to dismiss the "people > > want to build their own kernel" people entirely. > > > > One of the main sane use-cases for module signing is: > > > > - CONFIG_CHECK_SIGNATURE=y > > - randomly generated one-time key > > - "make modules_install; make install" > > - "make clean" to get rid of the keys. > > - reboot. > > > > and now you have a custom kernel that has the convenience of modules, > > yet is basically as safe as a non-modular build. The above makes it > > much harder for any kind of root-kit module to be loaded, and > > basically entirely avoids one fundamental security scare of modules. > > If you only want this, we could SHA all the built modules, put that in > the kernel, and verify the module being loaded matches one of them. > > Sure, it means a bit of trickery to get the module sums into the > bzImage, but the rest is trivial.
It also excludes out-of-tree drivers. I wouldn't personally shed a tear for them, but it eliminates a use-case that people could have if we just stuck to the signed module approach.
I'd prefer if we just cleaned up what we already have.
josh
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