Instead of blindly creating another bind mount for read-only mounts,
check if there's already one we can use, and if so, use it. Also,
recursively mark all submounts read-only too. Also, ignore autofs mounts
when remounting read-only unless they are already triggered.
This would otherwise unconditionally trigger any /boot autofs mount,
which we probably should avoid.
ProtectSystem= will now only cover /usr and (optionally) /etc, both of
which cannot be autofs anyway.
ProtectHome will continue to cover /run/user and /home. The former
cannot be autofs either. /home could be, however is frequently enough
used (unlikey /boot) so that it isn't too problematic to simply trigger
it unconditionally via ProtectHome=.
Also, rename ProtectedHome= to ProtectHome=, to simplify things a bit.
With this in place we now have two neat options ProtectSystem= and
ProtectHome= for protecting the OS itself (and optionally its
configuration), and for protecting the user's data.
Now that we moved the actual syslog socket to
/run/systemd/journal/dev-log we can actually make /dev/log a symlink to
it, when PrivateDevices= is used, thus making syslog available to
services using PrivateDevices=.
ReadOnlySystem= uses fs namespaces to mount /usr and /boot read-only for
a service.
ProtectedHome= uses fs namespaces to mount /home and /run/user
inaccessible or read-only for a service.
This patch also enables these settings for all our long-running services.
Together they should be good building block for a minimal service
sandbox, removing the ability for services to modify the operating
system or access the user's private data.
Similar to PrivateNetwork=, PrivateTmp= introduce PrivateDevices= that
sets up a private /dev with only the API pseudo-devices like /dev/null,
/dev/zero, /dev/random, but not any physical devices in them.
This way it is easy to only exclude directories from the current boot
from automatic clean up in /var/tmp.
Also, pick a longer name for the directories so that are globs in
tmp.conf can be simpler yet equally accurate.
This extends 62678ded 'efi: never call qsort on potentially
NULL arrays' to all other places where qsort is used and it
is not obvious that the count is non-zero.
Currently, PrivateTmp=yes means that the service cannot see the /tmp
shared by rest of the system and is isolated from other services using
PrivateTmp, but users can access and modify /tmp as seen by the
service.
Move the private /tmp and /var/tmp directories into a 0077-mode
directory. This way unpriviledged users on the system cannot see (or
modify) /tmp as seen by the service.
All Execs within the service, will get mounted the same
/tmp and /var/tmp directories, if service is configured with
PrivateTmp=yes. Temporary directories are cleaned up by service
itself in addition to systemd-tmpfiles. Directory which is mounted
as inaccessible is created at runtime in /run/systemd.
- don't use pivot_root() anymore, just reuse root hierarchy
- first create all mounts, then mark them read-only so that we get the
right behaviour when people want writable mounts inside of
read-only mounts
- don't pass invalid combinations of MS_ constants to the kernel
We finally got the OK from all contributors with non-trivial commits to
relicense systemd from GPL2+ to LGPL2.1+.
Some udev bits continue to be GPL2+ for now, but we are looking into
relicensing them too, to allow free copy/paste of all code within
systemd.
The bits that used to be MIT continue to be MIT.
The big benefit of the relicensing is that closed source code may now
link against libsystemd-login.so and friends.
