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BUG=b:214124318 TEST=no seccomp violations on kukui-arc-r Change-Id: Ida0450cb0f9eb82109c6129345f98e4afb210d30 Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3725614 Reviewed-by: Masami Hiramatsu <mhiramat@google.com> Reviewed-by: Kazuhiro Inaba <kinaba@chromium.org> Tested-by: kokoro <noreply+kokoro@google.com> Auto-Submit: Yiwei Zhang <zzyiwei@chromium.org> Reviewed-by: Keiichi Watanabe <keiichiw@chromium.org> Commit-Queue: Kazuhiro Inaba <kinaba@chromium.org> |
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README.md |
Policy files for crosvm
This folder holds the seccomp policies for crosvm devices, organized by architecture.
Each crosvm device can run within its owned jailed process. A jailed process is only able to perform the system calls specified in the seccomp policy file the jail has been created with, which improves security as a rogue process cannot perform any system call it wants.
Each device can run from different contexts, which require a different set of authorized system calls. This file explains how the policy files are named in order to allow these various scenario.
Naming conventions
Since Minijail only allows for one level of policy inclusion, we need to be a little bit creative in order to minimize policy duplication.
common_device.policy
contains a set of syscalls that are common to all devices, and is never loaded directly - only included from other policy files.foo.policy
contains the set of syscalls that devicefoo
is susceptible to use, regardless of the underlying virtio transport. This policy is also never loaded directly.foo_device.policy
is the policy that is loaded when devicefoo
is used as an in-VMM (i.e. regular virtio) device. It will generally simply includecommon_device.policy
as well asfoo.policy
.
When using vhost-user, the virtio protocol needs to be sent over a different medium, e.g. a Unix socket. Supporting this transport requires some extra system calls after the device is jailed, and thus dedicated policies:
vhost_user.policy
contains the set of syscalls required by the regular (i.e. socket-based) vhost-user listener. It is never loaded directly.vvu.policy
contains the set of syscalls required by the VFIO-based vhost-user (aka Virtio-Vhost-User) listener. It is also never loaded directly.foo_device_vhost_user.policy
is the policy that is loaded when devicefoo
is used as a regular vhost-user device. It will generally includecommon_device.policy
,vhost_user.policy
andfoo.policy
.foo_device_vvu.policy
is the policy that is loaded when devicefoo
is used as a VVU device. It will generally includecommon_device.policy
,vvu.policy
andfoo.policy
.