Let's clean up the interaction of StateDirectory= (and friends) to
DynamicUser=1: instead of creating these directories directly below
/var/lib, place them in /var/lib/private instead if DynamicUser=1 is
set, making that directory 0700 and owned by root:root. This way, if a
dynamic UID is later reused, access to the old run's state directory is
prohibited for that user. Then, use file system namespacing inside the
service to make /var/lib/private a readable tmpfs, hiding all state
directories that are not listed in StateDirectory=, and making access to
the actual state directory possible. Mount all directories listed in
StateDirectory= to the same places inside the service (which means
they'll now be mounted into the tmpfs instance). Finally, add a symlink
from the state directory name in /var/lib/ to the one in
/var/lib/private, so that both the host and the service can access the
path under the same location.
Here's an example: let's say a service runs with StateDirectory=foo.
When DynamicUser=0 is set, it will get the following setup, and no
difference between what the unit and what the host sees:
/var/lib/foo (created as directory)
Now, if DynamicUser=1 is set, we'll instead get this on the host:
/var/lib/private (created as directory with mode 0700, root:root)
/var/lib/private/foo (created as directory)
/var/lib/foo → private/foo (created as symlink)
And from inside the unit:
/var/lib/private (a tmpfs mount with mode 0755, root:root)
/var/lib/private/foo (bind mounted from the host)
/var/lib/foo → private/foo (the same symlink as above)
This takes inspiration from how container trees are protected below
/var/lib/machines: they generally reuse UIDs/GIDs of the host, but
because /var/lib/machines itself is set to 0700 host users cannot access
files in the container tree even if the UIDs/GIDs are reused. However,
for this commit we add one further trick: inside and outside of the unit
/var/lib/private is a different thing: outside it is a plain,
inaccessible directory, and inside it is a world-readable tmpfs mount
with only the whitelisted subdirs below it, bind mounte din. This
means, from the outside the dir acts as an access barrier, but from the
inside it does not. And the symlink created in /var/lib/foo itself
points across the barrier in both cases, so that root and the unit's
user always have access to these dirs without knowing the details of
this mounting magic.
This logic resolves a major shortcoming of DynamicUser=1 units:
previously they couldn't safely store persistant data. With this change
they can have their own private state, log and data directories, which
they can write to, but which are protected from UID recycling.
With this change, if RootDirectory= or RootImage= are used it is ensured
that the specified state/log/cache directories are always mounted in
from the host. This change of semantics I think is much preferable since
this means the root directory/image logic can be used easily for
read-only resource bundling (as all writable data resides outside of the
image). Note that this is a change of behaviour, but given that we
haven't released any systemd version with StateDirectory= and friends
implemented this should be a safe change to make (in particular as
previously it wasn't clear what would actually happen when used in
combination). Moreover, by making this change we can later add a "+"
modifier to these setings too working similar to the same modifier in
ReadOnlyPaths= and friends, making specified paths relative to the
container itself.
When putting together the namespace, always create the file or directory
we are supposed to bind mount on, the same way we do it for most other
stuff, for example mount units or systemd-nspawn's --bind= option.
This has the big benefit that we can use namespace bind mounts on dirs
in /tmp or /var/tmp even in conjunction with PrivateTmp=.
Before this patch we had an ordering problem: if we have no namespacing
enabled except for two bind mounts that intend to swap /a and /b via
bind mounts, then we'd execute the bind mount binding /b to /a, followed
by thebind mount from /a to /b, thus having the effect that /b is now
visible in both /a and /b, which was not intended.
With this change, as soon as any bind mount is configured we'll put
together the service mount namespace in a temporary directory instead of
operating directly in the root. This solves the problem in a
straightforward fashion: the source of bind mounts will always refer to
the host, and thus be unaffected from the bind mounts we already
created.
We already create /dev implicitly if PrivateTmp=yes is on, if it is
missing. Do so too for the other two API VFS, as well as for /dev if
PrivateTmp=yes is off but MountAPIVFS=yes is on (i.e. when /dev is bind
mounted from the host).
In most cases we followed the rule that the special _INVALID and _MAX
values we use in our enums use the full type name as prefix (in contrast
to regular values that we often make shorter), do so for
ExecDirectoryType as well.
No functional changes, just a little bit of renaming to make this code
more like the rest.
This is particularly useful when used in conjunction with DynamicUser=1,
where the UID might change for every invocation, but is useful in other
cases too, for example, when these directories are shared between
systems where the UID assignments differ slightly.
No need to wait for a timeout when we know things are not going to work out.
When the main process goes away and only notifications from the main process are
accepted, then we will not receive any notifications anymore.
Ignoring duplicate entry: 0001C8 = "THOMAS CONRAD CORP.", "CONRAD CORP."
Ignoring duplicate entry: 080030 = "NETWORK RESEARCH CORPORATION", "ROYAL MELBOURNE INST OF TECH"
Ignoring duplicate entry: 080030 = "NETWORK RESEARCH CORPORATION", "CERN"
→ we have two vendor prefixes with duplicate entries. For the first one,
there are two entries with what appear to be the same company. In the
second case, the same prefix is assigned to three different entities.
I arbitrarily chose to prefer the first entry.
This is rather slow (1 m 45 s on my laptop), but since it'd be only used
once per release, maybe this doesn't matter that much.
Output is identical to ids-update.pl with the set of source files committed in
the grandparent.
Without the original files it's hard to see what changed "upstream", and what
entries were added and removed. Upstream did not keep the entries sorted, and
our processing scripts did not sort the output either, so from just looking at
diffs it's hard to say what changed. So let's keep the original data, at least
for a few update cycles, so get a better handle on the upstream changes.
It's a few hundred kilobytes, so not that big, and text, so it should
compresses well.
ninja -c build hwdb-update
During the initial meson conversion, custom_target:s and run_target:s behaved
the same, and the target name became a top-level command. Now custom_target:s
require the subdir to be included, e.g. we have man/man target to build man pages,
but run_target:s not. So I think this target got a name that is so generic because
of the confusion caused by changing rules. Let's rename it.
Currently, all three of cgroup_good(), main_pid_good(),
control_pid_good() all return an "int" (two of them propagate errors).
It's a good thing to keep the three functions similar, so let's leave it
at that, but then let's clean up the invocation of the three functions
so that they always clearly acknowledge that the return value is not a
bool, but potentially negative.
The compiler should be good enough to figure this out on its own if this
is a static function, and it makes control_pid_good() an outlier anyway,
and decorators like this tend to bitrot. Hence, to keep things simple
and automatic, let's just drop the decorator.
The processes associated with a service are not just the ones in its
cgroup, but also the control and main processes, which might possibly
live outside of it, for example if they transitioned into their own
cgroups because they registered a PAM session of their own. Hence, if we
get a cgroup empty notification always check if the main PID is still
around before taking action too eagerly.
Fixes: #6045
The script wasn't apparently used since the switch to meson, because
it required the sys subdirectory to be present in the same subdirectory
where the output script is located.
Let's use f-strings to make the whole thing more readable. Add some
extra checks.
This is primarly useful to support escaped double quotes in PROGRAM or
IMPORT{program} directives.
The only possibilty before this patch was to use an external shell script but
this seems too cumbersome for trivial logics such as
PROGRAM=="/bin/sh -c 'FOO=\"%s{model}\"; echo ${FOO:0:4}'"
or any similar shell constructs that needs to deals with patterns including
whitespaces.
As it's the case for single quote and for directives running a program, words
within escaped double quotes will be considered as a single argument.
Fixes: #6835
Starting with kernel version 4.8 the kernel has a single `l3mdev` rule
that handles this. This rule will be created when the first VRF device
is added.
