
The ability to read these files may offer a power-based sidechannel attack against any workloads running on the same kernel. This was originally [CVE-2020-8694][1], which was fixed in [949dd0104c496fa7c14991a23c03c62e44637e71][2] by restricting read access to root. However, since many containers run as root, this is not sufficient for our use case. While untrusted code should ideally never be run, we can add some defense in depth here by masking out the device class by default. [Other mechanisms][3] to access this hardware exist, but they should not be accessible to a container due to other safeguards in the kernel/container stack (e.g. capabilities, perf paranoia). [1]: https://nvd.nist.gov/vuln/detail/CVE-2020-8694 [2]:949dd0104c
[3]: https://web.eece.maine.edu/~vweaver/projects/rapl/ Signed-off-by: Bjorn Neergaard <bjorn.neergaard@docker.com> (cherry picked from commit83cac3c3e3
) Signed-off-by: Bjorn Neergaard <bjorn.neergaard@docker.com>
181 lines
4.2 KiB
Go
181 lines
4.2 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/docker/docker/oci/caps"
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specs "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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// DefaultSpec returns the default spec used by docker for the current Platform
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func DefaultSpec() specs.Spec {
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if runtime.GOOS == "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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return 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: caps.DefaultCapabilities(),
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Permitted: caps.DefaultCapabilities(),
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Effective: caps.DefaultCapabilities(),
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},
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},
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Root: &specs.Root{},
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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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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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"/sys/devices/virtual/powercap",
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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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}
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}
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