org.osbuild.idmap

Recursively apply idmaps on all items in a given path

Stage to change the ownership of directories and files recursively by shifting the UID and GID based on an given idmapping. The mapping can be defined by

• using the same syntax as the X-mount.idmap from mount(8)
• using a user/group name from the subordinate files

The syntax based on the X-mount.idmap from mount(8) looks like this: id-type:id-mount:id-host:id-range

The id-type prefix specifies if the mapping is applied to UID, GID or both and can take the following values:

• u: only UIDs are mapped
• g: only GIDs are mapped
• b: UIDs and GIDs are mapped Omitting the id-type prefix is synonym to using b.

The id-host parameter specifies the current ID in the file system. The id-mount parameter specifies the starting ID to which the id-host gets mapped to. The id-range parameter indicates how many IDs are to be mapped.

For example, the following configuration would map UIDs and GIDs of all files and directories in /usr/lib/qm/rootfs:

type: org.osbuild.idmap options: items: /usr/lib/qm/rootfs:

• 'b:1000:0:10'

A file a owned by user 0:0 (UID:GID) would be changed to be owned by user 1000:1000. The ownership of a file b initially owned by user 1:1 would transition to user 1001:1001. And so on. If a file z is owned by user 20:20, however, then a mapping user 65534 (nobody) is applied.

By using a user/group name, a lookup to the current /etc/subuid and /etc/subgid is made searching for the specified names. If found, the ID ranges will be parsed and always mapped to the host-id 0 (root).

Schema 1

{
  "additionalProperties": false,
  "properties": {
    "items": {
      "type": "object",
      "description": "Paths to apply the idmapping for",
      "additionalProperties": false,
      "patternProperties": {
        "^\\/(?!\\.\\.)((?!\\/\\.\\.\\/).)+$": {
          "oneOf": [
            {
              "type": "array",
              "description": "List of idmaps to recursively apply to all items in the given path",
              "minItems": 1,
              "items": {
                "type": "string",
                "pattern": "^(?:(?:u|g|b):)?[0-9]+:[0-9]+:[1-9][0-9]*$"
              }
            },
            {
              "type": "object",
              "description": "Use the idmapping form the subordinate ID configuration of a user/group",
              "additionalProperties": false,
              "required": [
                "user",
                "group"
              ],
              "properties": {
                "user": {
                  "type": "string",
                  "description": "User in /etc/subuid to use for the idmapping",
                  "minLength": 1
                },
                "group": {
                  "type": "string",
                  "description": "Group in /etc/subgid to use for the idmapping",
                  "minLength": 1
                }
              }
            }
          ]
        }
      }
    }
  }
}

Schema 2

{}