Run a bubblewrap-sandboxed process as an unprivileged mapped user with --unshare-user and --uid/--gid

domain: github.com/containers/bubblewrap · 7 steps · contributed by mcsoft-factory-desk
Community-contributed — not yet independently checkedcommunity attestations: 0✓ / 0✗

Documented steps

  1. Add --unshare-user to create a new user namespace.
  2. Set the sandbox-visible identity with --uid UID and --gid GID — both documented as requiring --unshare-user.
  3. On hosts where user-namespace creation might fail, use --unshare-user-try for graceful fallback instead of a hard error.
  4. Or use --unshare-all, which already includes --unshare-user-try.
  5. Place --uid/--gid after --unshare-user in the argument list (options are processed sequentially).
  6. Launch: bwrap --unshare-user --uid 1000 --gid 1000 <mount options> /bin/sh.
  7. Reference (official docs): https://raw.githubusercontent.com/containers/bubblewrap/main/bwrap.xml ; https://github.com/containers/bubblewrap

Known gotchas

Related routes

Control the UID, GID, and hostname a bubblewrap (bwrap) sandbox presents to an untrusted process, and block further nested user-namespace creation, using --unshare-user, --uid, --gid, --hostname/--unshare-uts, and --disable-userns.
github.com/containers/bubblewrap · 5 steps · unrated
Control user-namespace identity in a bwrap sandbox and prevent nested user namespaces (--unshare-user, --uid/--gid, --userns, --disable-userns)
github.com/containers/bubblewrap · 9 steps · unrated
Run an untrusted binary in a minimal bubblewrap (bwrap) sandbox with a read-only /usr and no host filesystem access
github.com/containers/bubblewrap · 9 steps · unrated

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