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moby--moby/oci/devices_linux.go
Sebastiaan van Stijn 1cd1925acd
oci.Device() fix FileMode to match runtime spec
The runtime spec expects the FileMode field to only hold file permissions,
however `unix.Stat_t.Mode` contains both file type and mode.

This patch strips file type so that only file mode is included in the Device.

Thanks to Iceber Gu, who noticed the same issue in containerd and runc.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2021-02-18 10:48:24 +01:00

87 lines
2.8 KiB
Go

package oci // import "github.com/docker/docker/oci"
import (
"fmt"
"os"
"path/filepath"
"strings"
"github.com/opencontainers/runc/libcontainer/configs"
"github.com/opencontainers/runc/libcontainer/devices"
specs "github.com/opencontainers/runtime-spec/specs-go"
"golang.org/x/sys/unix"
)
// Device transforms a libcontainer configs.Device to a specs.LinuxDevice object.
func Device(d *configs.Device) specs.LinuxDevice {
return specs.LinuxDevice{
Type: string(d.Type),
Path: d.Path,
Major: d.Major,
Minor: d.Minor,
FileMode: fmPtr(int64(d.FileMode &^ unix.S_IFMT)), // strip file type, as OCI spec only expects file-mode to be included
UID: u32Ptr(int64(d.Uid)),
GID: u32Ptr(int64(d.Gid)),
}
}
func deviceCgroup(d *configs.Device) specs.LinuxDeviceCgroup {
return specs.LinuxDeviceCgroup{
Allow: true,
Type: string(d.Type),
Major: &d.Major,
Minor: &d.Minor,
Access: string(d.Permissions),
}
}
// DevicesFromPath computes a list of devices and device permissions from paths (pathOnHost and pathInContainer) and cgroup permissions.
func DevicesFromPath(pathOnHost, pathInContainer, cgroupPermissions string) (devs []specs.LinuxDevice, devPermissions []specs.LinuxDeviceCgroup, err error) {
resolvedPathOnHost := pathOnHost
// check if it is a symbolic link
if src, e := os.Lstat(pathOnHost); e == nil && src.Mode()&os.ModeSymlink == os.ModeSymlink {
if linkedPathOnHost, e := filepath.EvalSymlinks(pathOnHost); e == nil {
resolvedPathOnHost = linkedPathOnHost
}
}
device, err := devices.DeviceFromPath(resolvedPathOnHost, cgroupPermissions)
// if there was no error, return the device
if err == nil {
device.Path = pathInContainer
return append(devs, Device(device)), append(devPermissions, deviceCgroup(device)), nil
}
// if the device is not a device node
// try to see if it's a directory holding many devices
if err == devices.ErrNotADevice {
// check if it is a directory
if src, e := os.Stat(resolvedPathOnHost); e == nil && src.IsDir() {
// mount the internal devices recursively
// TODO check if additional errors should be handled or logged
_ = filepath.Walk(resolvedPathOnHost, func(dpath string, f os.FileInfo, _ error) error {
childDevice, e := devices.DeviceFromPath(dpath, cgroupPermissions)
if e != nil {
// ignore the device
return nil
}
// add the device to userSpecified devices
childDevice.Path = strings.Replace(dpath, resolvedPathOnHost, pathInContainer, 1)
devs = append(devs, Device(childDevice))
devPermissions = append(devPermissions, deviceCgroup(childDevice))
return nil
})
}
}
if len(devs) > 0 {
return devs, devPermissions, nil
}
return devs, devPermissions, fmt.Errorf("error gathering device information while adding custom device %q: %s", pathOnHost, err)
}