Flox 1.11.2 is avialable (Important hotfix)

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Important - Flox 1.11.2 release is available.

This is a hotfix for a recently disclosed vulnerability in Nix. Flox is based on Nix and felt the severity of this vulnerability warranted an immediate release to address the underlying issue. In multi-user Nix installations on Linux, the vulnerability could allow for root privilege escalation via Nix builds. More details below.

Hotfix for Nix vulnerability

This is a hotfix release to patch a vulnerability in Nix. See Sandbox escape: file write via symlink at FOD `.tmp` copy destination · Advisory · NixOS/nix · GitHub

For Linux installations of Flox, the vulnerability allows non-root users to gain root privileges by modifying sensitive files. macOS and container installations are not affected.

Full details from the Nix advisory:

  • A bug in the fix for CVE-2024-27297 allowed for arbitrary overwrites of files writable by the Nix process orchestrating the builds (typically the Nix daemon running as root in multi-user installations) by following symlinks during fixed-output derivation output registration. This affects sandboxed Linux builds - sandboxed macOS builds are unaffected. The location of the temporary output used for the output copy was located inside the build chroot. A symlink, pointing to an arbitrary location in the filesystem, could be created by the derivation builder at that path. During output registration, the Nix process (running in the host mount namespace) would follow that symlink and overwrite the destination with the derivation’s output contents.
  • In multi-user installations, this allows all users able to submit builds to the Nix daemon (allowed-users - defaulting to all users) to gain root privileges by modifying sensitive files.

Details relevant to Flox:

  • Flox installations outside of containers default to a multi-user installation with allowed-users defaulting to all. Questions and additional info can be found in our community slack.

Other fixes:

  • Manifest parse errors now include line and column information, making it easier to locate syntax errors.

Notes and download links are here.