Messages in this thread | | | Date | Wed, 26 Jan 2022 16:54:17 -0500 | Subject | Re: [PATCH v9 11/23] ima: Move ima_lsm_policy_notifier into ima_namespace | From | Stefan Berger <> |
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On 1/26/22 08:05, Christian Brauner wrote: > On Tue, Jan 25, 2022 at 05:46:33PM -0500, Stefan Berger wrote: >> From: Stefan Berger <stefanb@linux.ibm.com> >> >> Move the ima_lsm_policy_notifier into the ima_namespace. Each IMA >> namespace can now register its own LSM policy change notifier callback. >> The policy change notifier for the init_ima_ns still remains in init_ima() >> and therefore handle the registration of the callback for all other >> namespaces in init_ima_namespace(). >> >> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> >> --- > I'd double-check that this cannot be used to cause rcu stalls when a lot > of ima namespace with a lot of rules are used leading to a dos situation > during LSM policy update. The good thing at least is that an LSM policy > update can only be triggered for selinux for the whole system.
I just ran a test with up to 1920 IMA-namespaces each with 2 audit rules with the vmtools_exec_t label. Disabling of the vmtools SELinux module caused the rules to disappear in all IMA namespaces, as expected. However, it also added many kernel log lines 'ima: rule for LSM 'vmtools_exec_t' is undefined' to the kernel log that should probably be suppressed for ns != &init_ima_ns. Nothing bad happened otherwise. Also re-enabling the vmtools module didn't cause any kernel errors. So I think we should be fine.
https://github.com/stefanberger/ima-namespaces-tests/tree/master/audit-many-2
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