Commit Graph
6 Commits
Author SHA1 Message Date
Daniel P. Smith a0bb0960e5 flask: implement xsm_set_system_active
This commit implements full support for starting the idle domain privileged by
introducing a new flask label xenboot_t which the idle domain is labeled with
at creation.  It then provides the implementation for the XSM hook
xsm_set_system_active to relabel the idle domain to the existing xen_t flask
label.

In the reference flask policy a new macro, xen_build_domain(target), is
introduced for creating policies for dom0less/hyperlaunch allowing the
hypervisor to create and assign the necessary resources for domain
construction.

Signed-off-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
Tested-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Rahul Singh <rahul.singh@arm.com>
Tested-by: Rahul Singh <rahul.singh@arm.com>
2022-07-04 14:47:00 +02:00
Christopher Clark 2993eca828 xsm: policy hooks to require an IOMMU and interrupt remapping
Isolation of devices passed through to domains usually requires an
active IOMMU. The existing method of requiring an IOMMU is via a Xen
boot parameter ("iommu=force") which will abort boot if an IOMMU is not
available.

More graceful degradation of behaviour when an IOMMU is absent can be
achieved by enabling XSM to perform enforcement of IOMMU requirement.

This patch enables an enforceable XSM policy to specify that an IOMMU is
required for particular domains to access devices and how capable that
IOMMU must be. This allows a Xen system to boot whilst still
ensuring that an IOMMU is active before permitting device use.

Using a XSM policy ensures that the isolation properties remain enforced
even when the large, complex toolstack software changes.

For some hardware platforms interrupt remapping is a strict requirement
for secure isolation. Not all IOMMUs provide interrupt remapping.
The XSM policy can now optionally require interrupt remapping.

The device use hooks now check whether an IOMMU is:
 * Active and securely isolating:
    -- current criteria for this is that interrupt remapping is ok
 * Active but interrupt remapping is not available
 * Not active

This patch also updates the reference XSM policy to use the new
primitives, with policy entries that do not require an active IOMMU.

Signed-off-by: Christopher Clark <christopher.clark6@baesystems.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Ross Philipson <ross.philipson@gmail.com>
2017-08-23 17:47:04 +02:00
Daniel De Graaf 8ad651705c xsm: add missing permissions discovered in testing
Add two missing allow rules:

1. Device model domain construction uses getvcpucontext, discovered by
Andrew Cooper while chasing an unrelated issue.

2. When a domain is destroyed with a device passthrough active, the
calls to remove_{irq,ioport,iomem} can be made by the hypervisor itself
(which results in an XSM check with the source xen_t).  It does not make
sense to deny these permissions; no domain should be using xen_t, and
forbidding the hypervisor from performing cleanup is not useful.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
2016-11-07 10:55:51 +00:00
Daniel De Graaf d72fd26d5f flask/policy: move user definitions and constraints into modules
This also renames the example users created by vm_role.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Doug Goldstein <cardoe@cardoe.com>
2016-06-21 15:29:17 +01:00
Daniel De Graaf a2c8399a91 flask/policy: split out rules for system_r
When the all_system_role module is enabled, any domain type can be
created using the system_r role, which was the default.  When it is
disabled, domains not using the default types (dom0_t and domU_t) must
use another role such as vm_r.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Doug Goldstein <cardoe@cardoe.com>
2016-06-21 15:29:17 +01:00
Daniel De Graaf 31689dcb0f flask/policy: split into modules
This makes it easier to enable or disable parts of the XSM policy.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Doug Goldstein <cardoe@cardoe.com>
2016-06-21 15:29:17 +01:00