90087ac44f
Since we merged support for userns in: https://github.com/containerd/containerd/pull/7679 overlay has been doing a chown for the rootfs using WithRemapperLabels. Signed-off-by: Rodrigo Campos <rodrigoca@microsoft.com>
111 lines
3.2 KiB
Go
111 lines
3.2 KiB
Go
//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"
|
|
|
|
"github.com/containerd/containerd/snapshots"
|
|
)
|
|
|
|
const (
|
|
capabRemapIDs = "remap-ids"
|
|
)
|
|
|
|
// WithRemapperLabels creates the labels used by any supporting snapshotter
|
|
// to shift the filesystem ownership (user namespace mapping) automatically; currently
|
|
// supported by the fuse-overlayfs and overlay snapshotters
|
|
func WithRemapperLabels(ctrUID, hostUID, ctrGID, hostGID, length uint32) snapshots.Opt {
|
|
return snapshots.WithLabels(map[string]string{
|
|
snapshots.LabelSnapshotUIDMapping: fmt.Sprintf("%d:%d:%d", ctrUID, hostUID, length),
|
|
snapshots.LabelSnapshotGIDMapping: fmt.Sprintf("%d:%d:%d", ctrGID, hostGID, length)})
|
|
}
|
|
|
|
func resolveSnapshotOptions(ctx context.Context, client *Client, snapshotterName string, snapshotter snapshots.Snapshotter, parent string, opts ...snapshots.Opt) (string, error) {
|
|
capabs, err := client.GetSnapshotterCapabilities(ctx, snapshotterName)
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
|
|
for _, capab := range capabs {
|
|
if capab == capabRemapIDs {
|
|
// Snapshotter supports ID remapping, we don't need to do anything.
|
|
return parent, nil
|
|
}
|
|
}
|
|
|
|
var local snapshots.Info
|
|
for _, opt := range opts {
|
|
opt(&local)
|
|
}
|
|
|
|
needsRemap := false
|
|
var uidMap, gidMap string
|
|
|
|
if value, ok := local.Labels[snapshots.LabelSnapshotUIDMapping]; ok {
|
|
needsRemap = true
|
|
uidMap = value
|
|
}
|
|
if value, ok := local.Labels[snapshots.LabelSnapshotGIDMapping]; ok {
|
|
needsRemap = true
|
|
gidMap = value
|
|
}
|
|
|
|
if !needsRemap {
|
|
return parent, nil
|
|
}
|
|
|
|
var ctrUID, hostUID, length uint32
|
|
_, err = fmt.Sscanf(uidMap, "%d:%d:%d", &ctrUID, &hostUID, &length)
|
|
if err != nil {
|
|
return "", fmt.Errorf("uidMap unparsable: %w", err)
|
|
}
|
|
|
|
var ctrGID, hostGID, lengthGID uint32
|
|
_, err = fmt.Sscanf(gidMap, "%d:%d:%d", &ctrGID, &hostGID, &lengthGID)
|
|
if err != nil {
|
|
return "", fmt.Errorf("gidMap unparsable: %w", err)
|
|
}
|
|
|
|
if ctrUID != 0 || ctrGID != 0 {
|
|
return "", fmt.Errorf("Container UID/GID of 0 only supported currently (%d/%d)", ctrUID, ctrGID)
|
|
}
|
|
|
|
// TODO(dgl): length isn't taken into account for the intermediate snapshot id.
|
|
usernsID := fmt.Sprintf("%s-%d-%d", parent, hostUID, hostGID)
|
|
if _, err := snapshotter.Stat(ctx, usernsID); err == nil {
|
|
return usernsID, nil
|
|
}
|
|
mounts, err := snapshotter.Prepare(ctx, usernsID+"-remap", parent)
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
// TODO(dgl): length isn't taken into account here yet either.
|
|
if err := remapRootFS(ctx, mounts, hostUID, hostGID); err != nil {
|
|
snapshotter.Remove(ctx, usernsID+"-remap")
|
|
return "", err
|
|
}
|
|
if err := snapshotter.Commit(ctx, usernsID, usernsID+"-remap"); err != nil {
|
|
return "", err
|
|
}
|
|
|
|
return usernsID, nil
|
|
}
|