Skip to content

setns

Intro

setns - reassociate a process with a namespace.

Description

The setns() system call is used to associate a process with an existing namespace.

Namespaces are a feature of the Linux kernel that partition kernel resources such that one set of processes sees one set of resources, while another set sees a different set. The setns() system call enables processes to transition between these namespaces, or more technically, to be reassociated with different namespaces. It's an integral part of container technologies, where isolation of resources is paramount.

Arguments

  • fd:int[K] - File descriptor of the target namespace.
  • nstype:int[OPT] - An optional bitmask specifying the type of namespace. If this argument is zero, the type of namespace is inferred from the type of the file referred to by fd.

Namespace Types:

  • CLONE_NEWCGROUP: Cgroup namespace
  • CLONE_NEWIPC: IPC namespace
  • CLONE_NEWNET: Network namespace
  • CLONE_NEWNS: Mount namespace
  • CLONE_NEWPID: PID namespace
  • CLONE_NEWUSER: User namespace
  • CLONE_NEWUTS: UTS namespace

Available Tags

  • K - Originated from kernel-space.
  • U - Originated from user space.
  • TOCTOU - Vulnerable to TOCTOU (time of check, time of use).
  • OPT - Optional argument - might not always be available (passed with null value).

Hooks

sys_setns

Type

Tracepoint (through sys_enter).

Purpose

To monitor and capture instances when the setns() system call is executed, recording details on the type of namespace and the process being reassociated.

Example Use Case

In containerized environments, where process and resource isolation is vital, monitoring the invocation of setns() is pivotal to ensure processes are only engaging with the appropriate namespaces.

Issues

Misuse or misconfigurations with setns() might allow processes to access unintended namespaces, potentially undermining the isolation principles of container technologies and other namespace-dependent mechanisms.

  • unshare() - Disassociates parts of the process execution context.
  • clone() - Creates a child process, potentially sharing certain resources with the parent.

This document was automatically generated by OpenAI and reviewed by a Human.