Re: [PATCH 2/2] ima: Support appraise_type=imasig_optional
From: Vivek Goyal
Date: Thu Feb 14 2013 - 10:23:49 EST
On Thu, Feb 14, 2013 at 07:57:16AM -0500, Mimi Zohar wrote:
> > Ok, I will cleanup the code to do above. Just wanted to clear up one
> > point.
> > Above option will not have any effect on evm behavior? This only impacts
> > IMA appraisal behavior. For example, if security.ima is not present it
> > is fine and file access is allowed. But if EVM is enabled and initialized
> > and EVM does not find security.evm label (INTEGRITY_NOLABEL) or returns
> > INTEGRITY_NOXATTRS, file access should still be denied?
> Can't happen. evm_verifyxattr() is called from
> ima_appraise_measurement(), only if 'security.ima' exists.
Actually what I meant is following.
Currently in process_measurement(), I will allow access if
ima_appraise_measurement() returns INTEGRITY_NOLABEL.
Now this could mean 2 things.
- security.ima was not present.
- security.ima was there but security.evm was not present.
With appraise_type=optional, I think we would want to allow access in
first case but not the second one. IOW, appraise_type= affects behavior
of IMA and not EVM.
That means we need to introduce new codes.
INTEGRITY_IMA_NOLABEL and INTEGRITY_EVM_NOLABEL to differentiate between
above two cases?
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