Messages in this thread | | | Subject | Re: [PATCH 03/27] Enforce module signatures if the kernel is locked down | From | Mimi Zohar <> | Date | Thu, 02 Nov 2017 18:18:43 -0400 |
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On Thu, 2017-11-02 at 22:01 +0000, David Howells wrote: > Mimi Zohar <zohar@linux.vnet.ibm.com> wrote: > > > Right, it would never get here if the IMA signature verification > > fails. If sig_enforce is not enabled, then it will also work. So the > > only case is if sig_enforced is enabled and there is no key. > > > > eg. > > else if (can_do_ima_check && is_ima_appraise_enabled()) > > err = 0; > > I'm not sure where you want to put that, but I can't just do this: > > /* Not having a signature is only an error if we're strict. */ > if (err == -ENOKEY && !sig_enforce && > (!can_do_ima_check || !is_ima_appraise_enabled()) &&
The above IMA checks aren't needed here.
> !kernel_is_locked_down("Loading of unsigned modules")) > err = 0; > else if (can_do_ima_check && is_ima_appraise_enabled()) > err = 0; > > because that'll print out a message in lockdown mode saying that you're not > allowed to do that and then maybe do it anyway.
Then at least for now, document that even though kernel modules might be signed and verified by IMA-appraisal, that in lockdown mode they also require an appended signature.
Mimi
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