- Updated apptainer to version 1.3.0
* FUSE mounts are now supported in setuid mode, enabling full
functionality even when kernel filesystem mounts are insecure due to
unprivileged users having write access to raw filesystems in
containers. When allow `setuid-mount extfs = no` (the default) in
apptainer.conf, then the fuse2fs image driver will be used to mount
ext3 images in setuid mode instead of the kernel driver (ext3 images
are primarily used for the `--overlay` feature), restoring
functionality that was removed by default in Apptainer 1.1.8 because
of the security risk.
The allow `setuid-mount squashfs` configuration option in
`apptainer.conf` now has a new default called `iflimited` which allows
kernel squashfs mounts only if there is at least one `limit container`
option set or if Execution Control Lists are activated in ecl.toml.
If kernel squashfs mounts are are not allowed, then the squashfuse
image driver will be used instead.
`iflimited` is the default because if one of those limits are used
the system administrator ensures that unprivileged users do not have
write access to the containers, but on the other hand using FUSE
would enable a user to theoretically bypass the limits via `ptrace()`
because the FUSE process runs as that user.
The `fuse-overlayfs` image driver will also now be tried in setuid
mode if the kernel overlayfs driver does not work (for example if
one of the layers is a FUSE filesystem). In addition, if `allow
setuid-mount encrypted = no` then the unprivileged gocryptfs format
will be used for encrypting SIF files instead of the kernel
device-mapper. If a SIF file was encrypted using the gocryptfs
format, it can now be mounted in setuid mode in addition to
non-setuid mode.
* Change the default in user namespace mode to use either kernel