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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 02/19] flask/policy: Add domain relabel example
On Fri, 2012-11-16 at 18:28 +0000, Daniel De Graaf wrote:
> This adds the nomigrate_t type to the example FLASK policy which allows
> domains to be created that dom0 cannot access after building.
This is a very cool example of how even dom0's privileges can be
curtailed, I like it!
The fact that the domain can't be migrated is more of a side-effect
though I guess, but I can't really think of a better name (e.g.
"securedom_t" suggests other domains aren't etc...)
I'd ack it but this stuff is all Greek to me ;-)
>
> Example domain configuration snippet:
> seclabel='customer_1:vm_r:nomigrate_t'
> init_seclabel='customer_1:vm_r:nomigrate_t_building'
>
> Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
> ---
> docs/misc/xsm-flask.txt | 2 +
> tools/flask/policy/policy/modules/xen/xen.if | 56
> +++++++++++++++++++++-------
> tools/flask/policy/policy/modules/xen/xen.te | 10 +++++
> 3 files changed, 55 insertions(+), 13 deletions(-)
>
> diff --git a/docs/misc/xsm-flask.txt b/docs/misc/xsm-flask.txt
> index 6b0d327..0778a28 100644
> --- a/docs/misc/xsm-flask.txt
> +++ b/docs/misc/xsm-flask.txt
> @@ -60,6 +60,8 @@ that can be used without dom0 disaggregation. The main
> types for domUs are:
> - domU_t is a domain that can communicate with any other domU_t
> - isolated_domU_t can only communicate with dom0
> - prot_domU_t is a domain type whose creation can be disabled with a boolean
> + - nomigrate_t is a domain that must be created via the nomigrate_t_building
> + type, and whose memory cannot be read by dom0 once created
>
> HVM domains with stubdomain device models use two types (one per domain):
> - domHVM_t is an HVM domain that uses a stubdomain device model
> diff --git a/tools/flask/policy/policy/modules/xen/xen.if
> b/tools/flask/policy/policy/modules/xen/xen.if
> index 3f58909..2ad11b2 100644
> --- a/tools/flask/policy/policy/modules/xen/xen.if
> +++ b/tools/flask/policy/policy/modules/xen/xen.if
> @@ -9,24 +9,47 @@
> # Declare a type as a domain type, and allow basic domain setup
> define(`declare_domain', `
> type $1, domain_type`'ifelse(`$#', `1', `', `,shift($@)');
> + type $1_channel, event_type;
> + type_transition $1 domain_type:event $1_channel;
> allow $1 $1:grant { query setup };
> allow $1 $1:mmu { adjust physmap map_read map_write stat pinpage };
> allow $1 $1:hvm { getparam setparam };
> ')
>
> -# create_domain(priv, target)
> -# Allow a domain to be created
> -define(`create_domain', `
> +# declare_build_label(type)
> +# Declare a paired _building type for the given domain type
> +define(`declare_build_label', `
> + type $1_building, domain_type;
> + type_transition $1_building domain_type:event $1_channel;
> + allow $1_building $1 : domain transition;
> +')
> +
> +define(`create_domain_common', `
> allow $1 $2:domain { create max_vcpus setdomainmaxmem setaddrsize
> - getdomaininfo hypercall setvcpucontext scheduler
> - unpause getvcpuinfo getvcpuextstate getaddrsize
> - getvcpuaffinity };
> + getdomaininfo hypercall setvcpucontext setextvcpucontext
> + scheduler getvcpuinfo getvcpuextstate getaddrsize
> + getvcpuaffinity setvcpuaffinity };
> allow $1 $2:security check_context;
> allow $1 $2:shadow enable;
> allow $1 $2:mmu {map_read map_write adjust memorymap physmap pinpage};
> allow $1 $2:grant setup;
> - allow $1 $2:hvm { cacheattr getparam hvmctl irqlevel pciroute setparam
> pcilevel trackdirtyvram };
> - allow $1 $2_$1_channel:event create;
> + allow $1 $2:hvm { cacheattr getparam hvmctl irqlevel pciroute sethvmc
> setparam pcilevel trackdirtyvram };
> +')
> +
> +# create_domain(priv, target)
> +# Allow a domain to be created directly
> +define(`create_domain', `
> + create_domain_common($1, $2)
> + allow $1 $2_channel:event create;
> +')
> +
> +# create_domain_build_label(priv, target)
> +# Allow a domain to be created via its domain build label
> +define(`create_domain_build_label', `
> + create_domain_common($1, $2_building)
> + allow $1 $2_channel:event create;
> + allow $1 $2_building:domain2 relabelfrom;
> + allow $1 $2:domain2 relabelto;
> ')
>
> # manage_domain(priv, target)
> @@ -37,6 +60,15 @@ define(`manage_domain', `
> setvcpuaffinity setdomainmaxmem };
> ')
>
> +# migrate_domain_out(priv, target)
> +# Allow creation of a snapshot or migration image from a domain
> +# (inbound migration is the same as domain creation)
> +define(`migrate_domain_out', `
> + allow $1 $2:hvm { gethvmc getparam irqlevel };
> + allow $1 $2:mmu { stat pageinfo map_read };
> + allow $1 $2:domain { getaddrsize getvcpucontext getextvcpucontext
> getvcpuextstate pause destroy };
> +')
> +
>
> ################################################################################
> #
> # Inter-domain communication
> @@ -47,8 +79,6 @@ define(`manage_domain', `
> # This allows an event channel to be created from domains with labels
> # <source> to <dest> and will label it <chan-label>
> define(`create_channel', `
> - type $3, event_type;
> - type_transition $1 $2:event $3;
> allow $1 $3:event { create send status };
> allow $3 $2:event { bind };
> ')
> @@ -56,8 +86,8 @@ define(`create_channel', `
> # domain_event_comms(dom1, dom2)
> # Allow two domain types to communicate using event channels
> define(`domain_event_comms', `
> - create_channel($1, $2, $1_$2_channel)
> - create_channel($2, $1, $2_$1_channel)
> + create_channel($1, $2, $1_channel)
> + create_channel($2, $1, $2_channel)
> ')
>
> # domain_comms(dom1, dom2)
> @@ -72,7 +102,7 @@ define(`domain_comms', `
> # Allow a domain types to communicate with others of its type using grants
> # and event channels (this includes event channels to DOMID_SELF)
> define(`domain_self_comms', `
> - create_channel($1, $1, $1_self_channel)
> + create_channel($1, $1, $1_channel)
> allow $1 $1:grant { map_read map_write copy unmap };
> ')
>
> diff --git a/tools/flask/policy/policy/modules/xen/xen.te
> b/tools/flask/policy/policy/modules/xen/xen.te
> index 9550397..1162153 100644
> --- a/tools/flask/policy/policy/modules/xen/xen.te
> +++ b/tools/flask/policy/policy/modules/xen/xen.te
> @@ -90,6 +90,7 @@ create_domain(dom0_t, isolated_domU_t)
> manage_domain(dom0_t, isolated_domU_t)
> domain_comms(dom0_t, isolated_domU_t)
>
> +# Declare a boolean that denies creation of prot_domU_t domains
> gen_bool(prot_doms_locked, false)
> declare_domain(prot_domU_t)
> if (!prot_doms_locked) {
> @@ -111,6 +112,15 @@ manage_domain(dom0_t, dm_dom_t)
> domain_comms(dom0_t, dm_dom_t)
> device_model(dm_dom_t, domHVM_t)
>
> +# nomigrate_t must be built via the nomigrate_t_building label; once built,
> +# dom0 cannot read its memory.
> +declare_domain(nomigrate_t)
> +declare_build_label(nomigrate_t)
> +create_domain_build_label(dom0_t, nomigrate_t)
> +manage_domain(dom0_t, nomigrate_t)
> +domain_comms(dom0_t, nomigrate_t)
> +domain_self_comms(nomigrate_t)
> +
>
> ###############################################################################
> #
> # Device delegation
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