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runc 1.0-rc93 -- "I never could get the hang of Thursdays."

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@cyphar cyphar released this 04 Feb 00:18

This is the last feature-rich RC release and we are in a feature-freeze until
1.0. 1.0.0~rc94 will be released in a few weeks with minimal bug fixes only,
and 1.0.0 will be released soon afterwards.

  • runc's cgroupv2 support is no longer considered experimental. It is now
    believed to be fully ready for production deployments. In addition, runc's
    cgroup code has been improved:

    • The systemd cgroup driver has been improved to be more resilient and
      handle more systemd properties correctly.
    • We now make use of openat2(2) when possible to improve the security of
      cgroup operations (in future runc will be wholesale ported to libpathrs to
      get this protection in all codepaths).
  • runc's mountinfo parsing code has been reworked significantly, making
    container startup times significantly faster and less wasteful in general.

  • runc now has special handling for seccomp profiles to avoid making new
    syscalls unusable for glibc. This is done by installing a custom prefix to
    all seccomp filters which returns -ENOSYS for syscalls that are newer than
    any syscall in the profile (meaning they have a larger syscall number).

    This should not cause any regressions (because previously users would simply
    get -EPERM rather than -ENOSYS, and the rule applied above is the most
    conservative rule possible) but please report any regressions you find as a
    result of this change -- in particular, programs which have special fallback
    code that is only run in the case of -EPERM.

  • runc now supports the following new runtime-spec features:

    • The umask of a container can now be specified.
    • The new Linux 5.9 capabilities (CAP_PERFMON, CAP_BPF, and
      CAP_CHECKPOINT_RESTORE) are now supported.
    • The "unified" cgroup configuration option, which allows users to explicitly
      specify the limits based on the cgroup file names rather than abstracting
      them through OCI configuration. This is currently limited in scope to
  • Various rootless containers improvements:

    • runc will no longer cause conflicts if a user specifies a custom device
      which conflicts with a user-configured device -- the user device takes
    • runc no longer panics if /sys/fs/cgroup is missing in rootless mode.
  • runc --root is now always treated as local to the current working directory.

  • The --no-pivot-root hardening was improved to handle nested mounts properly
    (please note that we still strongly recommend that users do not use
    --no-pivot-root -- it is still an insecure option).

  • A large number of code cleanliness and other various cleanups, including
    fairly large changes to our tests and CI to make them all run more

For packagers the following changes have been made which will have impact on
your packaging of runc:

  • The "selinux" and "apparmor" buildtags have been removed, and now all runc
    builds will have SELinux and AppArmor support enabled. Note that "seccomp"
    is still optional (though we very highly recommend you enable it).

  • make install DESTDIR= now functions correctly.

Static Linking Notices

The runc binary distributed with this release are statically linked with
the following GNU LGPL-2.1 licensed libraries, with runc acting
as a "work that uses the Library":

The versions of these libraries were not modified from their upstream versions,
but in order to comply with the LGPL-2.1 (§6(a)), we have attached the
complete source code for those libraries which (when combined with the attached
runc source code) may be used to exercise your rights under the LGPL-2.1.

However we strongly suggest that you make use of your distribution's packages
or download them from the authoritative upstream sources, especially since
these libraries are related to the security of your containers.

Thanks to the following people who made this release possible:

Vote: +6 -0 #1
Signed-off-by: Aleksa Sarai