[systemd-devel] [Linux-ima-user] [PATCH 2/2] main: added support for loading IMA custom policies
roberto.sassu at polito.it
Tue Feb 21 05:58:17 PST 2012
On 02/21/2012 02:01 PM, Mimi Zohar wrote:
> On Tue, 2012-02-21 at 11:05 +0100, Roberto Sassu wrote:
>> Ok. this should be not a problem because all errors (IMA support not
>> included in the kernel, policy file access denied, ...) are ignored
>> except for the mmap() failure.
> Hi Roberto, IMA should never return an error, only IMA-appraisal should
> enforce file integrity. Can you please show me or send a patch?
do you intend a patch to reintroduce the 'ima=' kernel parameter for
enabling/disabling IMA? If so, i have not actually thought about this
but it should be not difficult to implement. Probably we can support
- disabled: IMA returns immediately to the system call;
- measure_only: IMA performs only measurements and does not return any
error to the system call;
- appraise_permissive: IMA stores measurements in the files extended
attribute and in the measurements list but does not return any error
to the system call even if the integrity check fails;
- appraise_enforce: IMA does the same as the previous mode but returns
an error to the system call if the integrity check fails.
Further, we can have a simple user-space package which will contain the
documentation about how to write a policy (so that it will be more
easy to find in respect to the whole kernel documentation) and a tool
that will fix/verify the measurements stored in the files extended
Having a separate user-space package will simplify the interaction for
users with the IMA kernel-space portion and will allow to determine
whether the IMA support should be enabled in Systemd.
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