mirror of
https://github.com/moby/moby.git
synced 2022-11-09 12:21:53 -05:00
64e52ff3db
@sw-pschmied originally post this in #38285 While looking through the Moby source code was found /proc/asound to be shared with containers as read-only (as defined in https://github.com/moby/moby/blob/master/oci/defaults.go#L128). This can lead to two information leaks. --- **Leak of media playback status of the host** Steps to reproduce the issue: - Listen to music/Play a YouTube video/Do anything else that involves sound output - Execute docker run --rm ubuntu:latest bash -c "sleep 7; cat /proc/asound/card*/pcm*p/sub*/status | grep state | cut -d ' ' -f2 | grep RUNNING || echo 'not running'" - See that the containerized process is able to check whether someone on the host is playing music as it prints RUNNING - Stop the music output - Execute the command again (The sleep is delaying the output because information regarding playback status isn't propagated instantly) - See that it outputs not running **Describe the results you received:** A containerized process is able to gather information on the playback status of an audio device governed by the host. Therefore a process of a container is able to check whether and what kind of user activity is present on the host system. Also, this may indicate whether a container runs on a desktop system or a server as media playback rarely happens on server systems. The description above is in regard to media playback - when examining `/proc/asound/card*/pcm*c/sub*/status` (`pcm*c` instead of `pcm*p`) this can also leak information regarding capturing sound, as in recording audio or making calls on the host system. Signed-off-by: Jonathan A. Schweder <jonathanschweder@gmail.com>
212 lines
4.6 KiB
Go
212 lines
4.6 KiB
Go
package oci // import "github.com/docker/docker/oci"
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import (
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"os"
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"runtime"
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"github.com/opencontainers/runtime-spec/specs-go"
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)
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func iPtr(i int64) *int64 { return &i }
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func u32Ptr(i int64) *uint32 { u := uint32(i); return &u }
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func fmPtr(i int64) *os.FileMode { fm := os.FileMode(i); return &fm }
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func defaultCapabilities() []string {
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return []string{
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"CAP_CHOWN",
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"CAP_DAC_OVERRIDE",
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"CAP_FSETID",
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"CAP_FOWNER",
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"CAP_MKNOD",
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"CAP_NET_RAW",
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"CAP_SETGID",
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"CAP_SETUID",
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"CAP_SETFCAP",
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"CAP_SETPCAP",
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"CAP_NET_BIND_SERVICE",
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"CAP_SYS_CHROOT",
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"CAP_KILL",
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"CAP_AUDIT_WRITE",
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}
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}
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// DefaultSpec returns the default spec used by docker for the current Platform
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func DefaultSpec() specs.Spec {
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return DefaultOSSpec(runtime.GOOS)
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}
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// DefaultOSSpec returns the spec for a given OS
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func DefaultOSSpec(osName string) specs.Spec {
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if osName == "windows" {
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return DefaultWindowsSpec()
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}
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return DefaultLinuxSpec()
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}
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// DefaultWindowsSpec create a default spec for running Windows containers
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func DefaultWindowsSpec() specs.Spec {
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return specs.Spec{
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Version: specs.Version,
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Windows: &specs.Windows{},
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Process: &specs.Process{},
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Root: &specs.Root{},
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}
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}
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// DefaultLinuxSpec create a default spec for running Linux containers
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func DefaultLinuxSpec() specs.Spec {
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s := specs.Spec{
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Version: specs.Version,
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Process: &specs.Process{
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Capabilities: &specs.LinuxCapabilities{
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Bounding: defaultCapabilities(),
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Permitted: defaultCapabilities(),
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Inheritable: defaultCapabilities(),
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Effective: defaultCapabilities(),
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},
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},
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Root: &specs.Root{},
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}
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s.Mounts = []specs.Mount{
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{
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Destination: "/proc",
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Type: "proc",
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Source: "proc",
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Options: []string{"nosuid", "noexec", "nodev"},
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},
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{
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Destination: "/dev",
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Type: "tmpfs",
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Source: "tmpfs",
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Options: []string{"nosuid", "strictatime", "mode=755", "size=65536k"},
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},
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{
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Destination: "/dev/pts",
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Type: "devpts",
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Source: "devpts",
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Options: []string{"nosuid", "noexec", "newinstance", "ptmxmode=0666", "mode=0620", "gid=5"},
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},
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{
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Destination: "/sys",
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Type: "sysfs",
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Source: "sysfs",
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Options: []string{"nosuid", "noexec", "nodev", "ro"},
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},
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{
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Destination: "/sys/fs/cgroup",
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Type: "cgroup",
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Source: "cgroup",
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Options: []string{"ro", "nosuid", "noexec", "nodev"},
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},
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{
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Destination: "/dev/mqueue",
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Type: "mqueue",
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Source: "mqueue",
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Options: []string{"nosuid", "noexec", "nodev"},
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},
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{
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Destination: "/dev/shm",
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Type: "tmpfs",
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Source: "shm",
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Options: []string{"nosuid", "noexec", "nodev", "mode=1777"},
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},
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}
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s.Linux = &specs.Linux{
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MaskedPaths: []string{
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"/proc/asound",
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"/proc/acpi",
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"/proc/kcore",
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"/proc/keys",
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"/proc/latency_stats",
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"/proc/timer_list",
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"/proc/timer_stats",
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"/proc/sched_debug",
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"/proc/scsi",
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"/sys/firmware",
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},
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ReadonlyPaths: []string{
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"/proc/bus",
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"/proc/fs",
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"/proc/irq",
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"/proc/sys",
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"/proc/sysrq-trigger",
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},
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Namespaces: []specs.LinuxNamespace{
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{Type: "mount"},
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{Type: "network"},
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{Type: "uts"},
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{Type: "pid"},
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{Type: "ipc"},
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},
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// Devices implicitly contains the following devices:
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// null, zero, full, random, urandom, tty, console, and ptmx.
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// ptmx is a bind mount or symlink of the container's ptmx.
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// See also: https://github.com/opencontainers/runtime-spec/blob/master/config-linux.md#default-devices
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Devices: []specs.LinuxDevice{},
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Resources: &specs.LinuxResources{
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Devices: []specs.LinuxDeviceCgroup{
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{
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Allow: false,
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Access: "rwm",
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},
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{
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Allow: true,
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Type: "c",
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Major: iPtr(1),
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Minor: iPtr(5),
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Access: "rwm",
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},
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{
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Allow: true,
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Type: "c",
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Major: iPtr(1),
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Minor: iPtr(3),
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Access: "rwm",
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},
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{
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Allow: true,
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Type: "c",
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Major: iPtr(1),
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Minor: iPtr(9),
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Access: "rwm",
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},
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{
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Allow: true,
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Type: "c",
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Major: iPtr(1),
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Minor: iPtr(8),
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Access: "rwm",
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},
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{
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Allow: true,
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Type: "c",
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Major: iPtr(5),
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Minor: iPtr(0),
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Access: "rwm",
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},
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{
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Allow: true,
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Type: "c",
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Major: iPtr(5),
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Minor: iPtr(1),
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Access: "rwm",
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},
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{
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Allow: false,
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Type: "c",
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Major: iPtr(10),
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Minor: iPtr(229),
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Access: "rwm",
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},
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},
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},
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}
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// For LCOW support, populate a blank Windows spec
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if runtime.GOOS == "windows" {
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s.Windows = &specs.Windows{}
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}
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return s
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}
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