IRQs can be shared between devices, so using the same label as the PCI
device can create conflicts where the IRQ is labeled with one of the
device labels preventing assignment of the second device to the second
domain. Add the ability to specify an irq label distinct from the PCI
device, so a shared irq label can be specified. The policy would then
be written such that the two domains can each use the shared IRQ type in
addition to their labeled PCI device. That way we can still label most
of the PCI device resources and assign devices in the face of shared
IRQs.
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Change the url scheme to https. This is all in-tree references to
xenbits and the main website except for those in Config.mk.
We leave Config.mk alone for now because those urls are used by CI
systems and we need to check that nothing breaks when we change the
download method.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
This adds a Kconfig option and support for including the XSM policy from
tools/flask/policy in the hypervisor so that the bootloader does not
need to provide a policy to get sane behavior from an XSM-enabled
hypervisor. The policy provided by the bootloader, if present, will
override the built-in policy.
The XSM policy is not moved out of tools because that remains the
primary location for installing and configuring the policy.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
This adds a Kconfig option and support for including the XSM policy from
tools/flask/policy in the hypervisor so that the bootloader does not
need to provide a policy to get sane behavior from an XSM-enabled
hypervisor. The policy provided by the bootloader, if present, will
override the built-in policy.
Enabling this option only builds the policy if checkpolicy is available
during compilation of the hypervisor; otherwise, it does nothing. The
XSM policy is not moved out of tools because that remains the primary
location for installing and configuring the 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>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Julien Grall <julien.grall@arm.com>
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>
As discussed on the hackathon, avoid us having to issue security
advisories for issues affecting only heavily disaggregated tool stack
setups, which no-one appears to use (or else they should step up to get
things into shape).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
The previous default of "permissive" is meant for developing or
debugging a disaggregated system. However, this default makes it too
easy to accidentally boot a machine in this state, which does not place
any restrictions on guests. This is not suitable for normal systems
because any guest can perform any operation (including operations like
rebooting the machine, kexec, and reading or writing another domain's
memory).
This change will cause the boot to fail if you do not specify an XSM
policy during boot; if you need to load a policy from dom0, use the
"flask=late" boot parameter.
Original patch by Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>; modified
to also change the default value of flask_enforcing so that the policy
is not still in permissive mode. This also removes the (no longer
documented) command line argument directly changing that variable since
it has been superseded by the flask= parameter.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Converts the existing XSM_ENABLE flag from Config.mk to CONFIG_XSM
within Kconfig. This also re-adds the dependency of CONFIG_FLASK on
CONFIG_XSM.
Signed-off-by: Doug Goldstein <cardoe@cardoe.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Converts the Config.mk option of FLASK_ENABLE into a Kconfig option for
the hypervisor called CONFIG_FLASK. This commit knowingly breaks the
dependent relationship on XSM_ENABLE which is addressed when XSM_ENABLE
is converted to Kconfig.
Signed-off-by: Doug Goldstein <cardoe@cardoe.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Converts the existing XSM_ENABLE flag from Config.mk to CONFIG_XSM
within Kconfig. This also re-adds the dependency of CONFIG_FLASK on
CONFIG_XSM.
Signed-off-by: Doug Goldstein <cardoe@cardoe.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Converts the Config.mk option of FLASK_ENABLE into a Kconfig option for
the hypervisor called CONFIG_FLASK. This commit knowingly breaks the
dependent relationship on XSM_ENABLE which is addressed when XSM_ENABLE
is converted to Kconfig.
Signed-off-by: Doug Goldstein <cardoe@cardoe.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Add default security contexts to the XSM policy for use by the toolstack
when a domain is created without specifying an explicit security label.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
In this patch we mechanically rename mem_event to vm_event. This patch
introduces no logic changes to the code. Using the name vm_event better
describes the intended use of this subsystem, which is not limited to memory
events. It can be used for off-loading the decision making logic into helper
applications when encountering various events during a VM's execution.
Signed-off-by: Tamas K Lengyel <tamas.lengyel@zentific.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Commit 2090f14c5c ("sysctl: make XEN_SYSCTL_topologyinfo sysctl a
little more efficient") renamed XEN_SYSCTL_topologyinfo to
XEN_SYSCTL_cputopoinfo.
It, however, neglected to update this macro for flask-related files.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reported-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
The definitions of static device labels must be placed at the end of the
policy.conf before passing it to checkpolicy; the existing examples
(which are commented out) are in the wrong location. Create a new file
for device contexts which will place them in the proper location.
This also removes some directions about using the xen policy type in
checkpolicy which is no longer needed.
Reported-by: Julien Grall <julien.grall@linaro.org>
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
This unifies the flask_enforcing and flask_enabled boot parameters into
a single parameter with additional states. Defined options are:
enforcing - require policy to be loaded at boot time and enforce it
permissive - a missing or broken policy does not panic
disabled - revert to dummy (no XSM) policy. Was flask_enabled=0
late - bootloader policy is not used; later loadpolicy is enforcing
The default mode remains "permissive" and the flask_enforcing boot
parameter is retained for compatibility. If flask_enforcing=1 is
specified and flask= is not, the bootloader policy will be loaded in
enforcing mode if present, but errors will disable access controls until
a successful loadpolicy instead of causing a panic at boot.
Suggested-by: Julien Grall <julien.grall@linaro.org>
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
XEN_DOMCTL_gdbsx_domstatus is already safe. It loops at most over every vcpu
in a domain and breaks at the first vcpu with an event pending, marking it as
not-pending.
XEN_DOMCTL_gdbsx_pausevcpu had an incorrect bounds check against the vcpu id,
allowing an overflow of d->vcpu[] with an id between d->max_vcpus and
MAX_VIRT_CPUS. It was also able to overflow a vcpus pause count by many
repeated hypercalls.
The bounds check is fixed, and vcpu_pause() has been replaced with
vcpu_pause_by_systemcontroller() which cuts out at 255 uses.
XEN_DOMCTL_gdbsx_unpausevcpu suffered from the same bounds problems as its
pause counterpart, and is fixed in exactly the same way. Despite the
atomic_read(&v->pause_count), this code didn't successfully prevent against an
underflow of the vcpu pause count.
The vcpu_unpause() has been replaced with vcpu_pause_by_systemcontroller()
which correctly prevents against underflow. The printk() is updated to have a
proper guest logging level, and provide more useful information in the XSM
case of one domain having debugger privileges over another.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Tim Deegan <tim@xen.org>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
With proper permission (and, for the I/O port case, wrap-around) checks
added (note that for the I/O port case a count of zero is now being
disallowed, in line with I/O memory handling):
XEN_DOMCTL_irq_permission:
XEN_DOMCTL_ioport_permission:
Of both IRQs and I/O ports there is only a reasonably small amount, so
there's no excess resource consumption involved here. Additionally
they both have a specialized XSM hook associated.
XEN_DOMCTL_iomem_permission:
While this also has a specialized XSM hook associated (just like
XEN_DOMCTL_{irq,ioport}_permission), it's not clear whether it's
reasonable to expect XSM to restrict the number of ranges associated
with a domain via this hook (which is the main resource consumption
item here).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Tim Deegan <tim@xen.org>
In a number of cases, loops over each vCPU in a domain are involved
here. For large numbers of vCPU-s these may still take some time to
complete, but we're limiting them at a couple of thousand at most, so I
would think this should not by itself be an issue. I wonder though
whether it shouldn't be possible to have XSM restrict the vCPU count
that can be set through XEN_DOMCTL_max_vcpus.
XEN_DOMCTL_pausedomain:
A loop over vcpu_sleep_sync() for each of vCPU in the domain. That
function itself has a loop waiting for the subject vCPU to become non-
runnable, which ought to complete quickly (involving an IPI to be sent
and acted on). No other unbounded resource usage.
XEN_DOMCTL_unpausedomain:
Simply a loop calling vcpu_wake() (not having any loops or other
resource usage itself) for each of vCPU in the domain.
XEN_DOMCTL_getdomaininfo:
Two loops (one over all domains, i.e. bounded by the limit of 32k
domains, and another over all vCPU-s in the domain); no other
unbounded resource usage.
XEN_DOMCTL_getpageframeinfo:
Inquiring just a single MFN, i.e. no loops and no other unbounded
resource usage.
XEN_DOMCTL_getpageframeinfo{2,3}:
Number of inquired MFNs is limited to 1024. Beyond that just like
XEN_DOMCTL_getpageframeinfo.
XEN_DOMCTL_getvcpuinfo:
Only obtaining information on the vCPU, no loops or other resource
usage.
XEN_DOMCTL_setdomainhandle:
Simply a memcpy() of a very limited amount of data.
XEN_DOMCTL_setdebugging:
A domain_{,un}pause() pair (see XEN_DOMCTL_{,un}pausedomain) framing
the setting of a flag.
XEN_DOMCTL_hypercall_init:
Initializing a guest provided page with hypercall stubs. No other
resource consumption.
XEN_DOMCTL_arch_setup:
IA64 leftover, interface structure being removed from the public
header.
XEN_DOMCTL_settimeoffset:
Setting a couple of guest state fields. No other resource consumption.
XEN_DOMCTL_getvcpuaffinity:
XEN_DOMCTL_getnodeaffinity:
Involve temporary memory allocations (approximately) bounded by the
number of CPUs in the system / number of nodes built for, which is
okay. Beyond that trivial operation.
XEN_DOMCTL_real_mode_area:
PPC leftover, interface structure being removed from the public
header.
XEN_DOMCTL_resumedomain:
A domain_{,un}pause() pair framing operation very similar to
XEN_DOMCTL_unpausedomain (see above).
XEN_DOMCTL_sendtrigger:
Injects an interrupt (SCI or NMI) without any other resource
consumption.
XEN_DOMCTL_subscribe:
Updates the suspend event channel, i.e. affecting only the controlled
domain.
XEN_DOMCTL_disable_migrate:
XEN_DOMCTL_suppress_spurious_page_faults:
Just setting respective flags on the domain.
XEN_DOMCTL_get_address_size:
Simply reading the guest property.
XEN_DOMCTL_set_opt_feature:
Was already tagged IA64-only.
XEN_DOMCTL_set_cpuid:
MAX_CPUID_INPUT bounded loop, which is okay. No other resource
consumption.
XEN_DOMCTL_get_machine_address_size:
Simply obtaining the value set by XEN_DOMCTL_set_machine_address_size
(or the default set at domain creation time).
XEN_DOMCTL_gettscinfo:
XEN_DOMCTL_settscinfo:
Reading/writing of a couple of guest state fields wrapped in a
domain_{,un}pause() pair.
XEN_DOMCTL_audit_p2m:
Enabled only in debug builds.
XEN_DOMCTL_set_max_evtchn:
While the limit set here implies other (subsequent) resource usage,
this is the purpose of the operation.
I also verified that all removed domctls' handlers don't leak
hypervisor memory contents .
Inspected but questionable (and hence left in place for now):
XEN_DOMCTL_max_mem:
While only setting the field capping a domain's allocation (this
implies potential successive resource usage, but that's the purpose of
the operation). However, XSM doesn't see the value that's being set
here, so the net effect would be potential unbounded memory use.
XEN_DOMCTL_set_virq_handler:
This modifies a global array. While that is the purpose of the
operation, if multiple domains are granted permission they can badly
interfere with one another. Hence I'd appreciate a second opinion
here. [Andrew confirms that this being the nature of the operation,
it's fine to be removed from the list - will be done in a 2nd round.]
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Tim Deegan <tim@xen.org>
List all the sub ops of:
__HYPERVISOR_domctl
__HYPERVISOR_sysctl
__HYPERVISOR_memory_op
__HYPERVISOR_tmem_op
which are subject to the policy given in
http://xenbits.xen.org/xsa/advisory-77.html
It is expected that these lists will be whittled away as each interface is
audited for safety.
New interfaces should be expected to be safe when introduced (IOW the list
should never be expanded).
This is XSA-77.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Because the FLASK XSM module no longer checks IS_PRIV for remote
domain accesses covered by XSM permissions, domains now have the
ability to perform memory management and other functions on all
domains that have the same type. While it is possible to prevent this
by only creating one domain per type, this solution significantly
limits the flexibility of the type system.
This patch introduces a domain type transition to represent a domain
that is operating on itself. In the example policy, this is
demonstrated by creating a type with _self appended when declaring a
domain type which will be used for reflexive operations. AVCs for a
domain of type domU_t will look like the following:
scontext=system_u:system_r:domU_t
tcontext=system_u:system_r:domU_t_self
This change also allows policy to distinguish between event channels a
domain creates to itself and event channels created between domains of
the same type.
The IS_PRIV_FOR check used for device model domains is also no longer
checked by FLASK; a similar transition is performed when the target is
set and used when the device model accesses its target domain.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Committed-by: Keir Fraser <keir@xen.org>
Allow a domain to be built under one security label and run using a
different label. This can be used to prevent the domain builder or
control domain from having the ability to access a guest domain's memory
via map_foreign_range except during the build process where this is
required.
Example domain configuration snippet:
seclabel='customer_1:vm_r:nomigrate_t'
init_seclabel='customer_1:vm_r:nomigrate_t_building'
Note: this does not provide complete protection from a malicious dom0;
mappings created during the build process may persist after the relabel,
and could be used to indirectly access the guest's memory. However, if
dom0 correctly unmaps the domain upon building, a the domU is protected
against dom0 becoming malicious in the future.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
This shows an example boolean (prot_doms_locked) which can be set at
runtime to prevent dom0 from mapping memory of domains of type
prot_domU_t.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Committed-by: Keir Fraser <keir@xen.org>
These examples show how to use constraints and the user field of the
security label to prevent communication between virtual machines of
different customers in a multi-tenant environment.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Committed-by: Keir Fraser <keir@xen.org>
Add support for Xen ocontext records to enable device polices. The
default policy will not be changed and instructions have been added to
enable the new functionality. Examples on how to use the new policy
language have been added but commented out. The newest version of
checkpolicy (>= 2.0.20) and libsepol (>= 2.0.39) is needed in order to
compile it. Devices can be labeled and enforced using the following
new commands; pirqcon, iomemcon, ioportcon and pcidevicecon.
Signed-off-by : George Coker <gscoker@alpha.ncsc.mil>
Signed-off-by : Paul Nuzzi <pjnuzzi@tycho.ncsc.mil>
Update the XSM Flask documentation to reflect the support for
policy.24, the updated policy and policy build infrastructure, and how
to enable the optional MLS policy.
Signed-off-by: Stephen D. Smalley <sds@tycho.nsa.gov>
Signed-off-by: George S. Coker, II <gscoker@alpha.ncsc.mil>
- A simple txt howto based on previous list discussions and observations
- A oneliner patch to address a compiler type cast error for x86_64
Signed-off-by: George S. Coker, II <gscoker@alpha.ncsc.mil>
Jason Andryuk
Ian Jackson
Wei Liu
Daniel De Graaf
Jan Beulich
Doug Goldstein
Tamas K Lengyel
Boris Ostrovsky
Andrew Cooper
Ian Campbell
Tim Deegan
Keir Fraser
Keir Fraser