117 lines
3.4 KiB
Go
117 lines
3.4 KiB
Go
// +build !windows
|
|
|
|
/*
|
|
Copyright The containerd Authors.
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
*/
|
|
|
|
package containerd
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"os"
|
|
"path/filepath"
|
|
"syscall"
|
|
|
|
"github.com/containerd/containerd/containers"
|
|
"github.com/containerd/containerd/errdefs"
|
|
"github.com/containerd/containerd/mount"
|
|
"github.com/opencontainers/image-spec/identity"
|
|
)
|
|
|
|
// WithRemappedSnapshot creates a new snapshot and remaps the uid/gid for the
|
|
// filesystem to be used by a container with user namespaces
|
|
func WithRemappedSnapshot(id string, i Image, uid, gid uint32) NewContainerOpts {
|
|
return withRemappedSnapshotBase(id, i, uid, gid, false)
|
|
}
|
|
|
|
// WithRemappedSnapshotView is similar to WithRemappedSnapshot but rootfs is mounted as read-only.
|
|
func WithRemappedSnapshotView(id string, i Image, uid, gid uint32) NewContainerOpts {
|
|
return withRemappedSnapshotBase(id, i, uid, gid, true)
|
|
}
|
|
|
|
func withRemappedSnapshotBase(id string, i Image, uid, gid uint32, readonly bool) NewContainerOpts {
|
|
return func(ctx context.Context, client *Client, c *containers.Container) error {
|
|
diffIDs, err := i.(*image).i.RootFS(ctx, client.ContentStore(), client.platform)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
var (
|
|
parent = identity.ChainID(diffIDs).String()
|
|
usernsID = fmt.Sprintf("%s-%d-%d", parent, uid, gid)
|
|
)
|
|
c.Snapshotter, err = client.resolveSnapshotterName(ctx, c.Snapshotter)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
snapshotter, err := client.getSnapshotter(ctx, c.Snapshotter)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if _, err := snapshotter.Stat(ctx, usernsID); err == nil {
|
|
if _, err := snapshotter.Prepare(ctx, id, usernsID); err == nil {
|
|
c.SnapshotKey = id
|
|
c.Image = i.Name()
|
|
return nil
|
|
} else if !errdefs.IsNotFound(err) {
|
|
return err
|
|
}
|
|
}
|
|
mounts, err := snapshotter.Prepare(ctx, usernsID+"-remap", parent)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if err := remapRootFS(ctx, mounts, uid, gid); err != nil {
|
|
snapshotter.Remove(ctx, usernsID)
|
|
return err
|
|
}
|
|
if err := snapshotter.Commit(ctx, usernsID, usernsID+"-remap"); err != nil {
|
|
return err
|
|
}
|
|
if readonly {
|
|
_, err = snapshotter.View(ctx, id, usernsID)
|
|
} else {
|
|
_, err = snapshotter.Prepare(ctx, id, usernsID)
|
|
}
|
|
if err != nil {
|
|
return err
|
|
}
|
|
c.SnapshotKey = id
|
|
c.Image = i.Name()
|
|
return nil
|
|
}
|
|
}
|
|
|
|
func remapRootFS(ctx context.Context, mounts []mount.Mount, uid, gid uint32) error {
|
|
return mount.WithTempMount(ctx, mounts, func(root string) error {
|
|
return filepath.Walk(root, incrementFS(root, uid, gid))
|
|
})
|
|
}
|
|
|
|
func incrementFS(root string, uidInc, gidInc uint32) filepath.WalkFunc {
|
|
return func(path string, info os.FileInfo, err error) error {
|
|
if err != nil {
|
|
return err
|
|
}
|
|
var (
|
|
stat = info.Sys().(*syscall.Stat_t)
|
|
u, g = int(stat.Uid + uidInc), int(stat.Gid + gidInc)
|
|
)
|
|
// be sure the lchown the path as to not de-reference the symlink to a host file
|
|
return os.Lchown(path, u, g)
|
|
}
|
|
}
|