File System Access

Simple Story

This is the list of papers a pupil may pick up, and what they may do with each one.

Anything not on the list stays out of reach. And being allowed to pick something up is not permission to do as you like with it: reading, replacing, creating, running and destroying are five separate permissions, each granted on its own.

Position in the example policy file

The section documented on this page is marked in red. Every page in this section shows the same example file, so reading them in order walks it from top to bottom.

security-policy.yaml
thisPolicyFileCompliesToThePolicyVersion: 1
regardingTheSupervisedCode:
  theFollowingProgrammingLanguageConfigurationIsUsed: JAVA_USING_MAVEN_WALA_AND_ASPECTJ
  theSupervisedCodeUsesTheFollowingPackage: "org.example"
  theMainClassInsideThisPackageIs: "Main"

  theFollowingClassesAreTestClasses:
    - "org.example.PenguinTest"

  theFollowingResourceAccessesArePermitted:

    regardingFileSystemInteractions:
      - onThisPathAndAllPathsBelow: "something.txt"
        readAllFiles: true
        overwriteAllFiles: true
        createAllFiles: true
        executeAllFiles: false
        deleteAllFiles: false

    regardingNetworkConnections:
      - onTheHost: "www.example.com"
        onThePort: 80
        openConnections: true
        sendData: true
        receiveData: true

    regardingCommandExecutions:
      - executeTheCommand: "ls"
        withTheseArguments:
          - "-l"

    regardingThreadCreations:
      - createTheFollowingNumberOfThreads: 10
        ofThisClass: "org.example.Worker"

    regardingPackageImports:
      - importTheFollowingPackage: "java.util"

    regardingTimeouts:
      - timeout: 120000

Fields

Implemented by FilePermission in policy/policySubComponents/FilePermission.java.

Field	Datatype	Explanation	Example	Regex or Range
`onThisPathAndAllPathsBelow`	`String`	The path this entry governs, and everything beneath it.	`something.txt`	`FILE_PATH_PATTERN`: either ``, or a non-blank path containing no `` and no NUL byte, which must not traverse upwards with `..`. The placeholders `${PROJECT_ROOT}`, `${java.home}`, `${user.home}` and `${java.io.tmpdir}` are recognised; any other `${...}` is rejected.
`readAllFiles`	`boolean`	Permits reading below the path.	`true`	`true` or `false`. Required: an entry that omits it is rejected on load.
`overwriteAllFiles`	`boolean`	Permits replacing the contents of existing files below the path.	`true`	`true` or `false`. Required: an entry that omits it is rejected on load.
`createAllFiles`	`boolean`	Permits creating new files below the path.	`true`	`true` or `false`. Required: an entry that omits it is rejected on load.
`executeAllFiles`	`boolean`	Permits executing files below the path.	`false`	`true` or `false`. Required: an entry that omits it is rejected on load.
`deleteAllFiles`	`boolean`	Permits deleting files below the path.	`false`	`true` or `false`. Required: an entry that omits it is rejected on load.

Notes

createRestrictive(path) builds an entry that names a path and grants nothing, which is how a deny-all default is expressed for a path that must still be mentioned.

All six fields are required. SecurityPolicySchemaValidator passes the file field set as both the accepted and the required set, so an entry that leaves a boolean out is rejected when the policy is loaded rather than read as a denial. Write false explicitly for every operation the entry does not permit. Omitting the whole entry is what expresses "nothing is permitted here".

The .. rejection is a security property rather than a convenience: without it a policy entry could name a path inside the project and resolve to one outside it.

Position in the example policy file​

Fields​

Notes​

Position in the example policy file

Fields

Notes