I tried to be conservative here, and hence in doubt I left the flag off,
but in some cases I really can't see any reason why it would make sense
to specifiy paths into API VFS, hence add it there, to lock things down
a bit.
In various contexts it's a bit icky to allow paths below /proc/, /sys/,
/dev/ i.e. file hierarchies where API VFS are placed. Let's add a new
flag for path_simplify_and_warn() to check for this and refuse a path if
in these paths.
Enable this when parsing WorkingDirectory=.
This is inspired by CVE-2024-21626, which uses trickery around the cwd
and /proc/self/fd/.
AFAICS we are not actually vulnerable to the same issue as explained in
the CVE since we execute the WorkingDirectory= setting very late, i.e.
long after we set up the new mount namespace. But let's filter out icky
stuff better earlier than later, as extra safety precaution.
This file is a bit misnamed. What it actually implements is one specific
BPF LSM module, that restricts file systems. As such it really should be
named after that, and not primarily by the mechanism it uses for that.
With this our glue code is now named the same way as the actual bpf code
files in src/core/bpf/, thus things become a bit more symmetric.
This is particular relevant as we'll soon have another BPF LSM in our
tree, see #26826, and we should be able to distinguish them by name.
This commit just renames the files and does some dumb search/replace of
the string. A follow-up commit will name some functions more expressively
inside the files.
We can only delegate actual controllers, not the BPF pseudo-controllers
we defined as there's imply no concept for that. Hence, when users set
Delegate=yes to do a wildcard delegation, only delegate the regular
controllers.
This means that we won't bother with BPF stuff for such units where it's
entirelly unnecessary.
This patch enables IFNAME_VALID_ALTERNATIVE for checks guarding the
parsing of RestrictNetworkInterfaces=.
The underlying implementation for this option already supports
altnames.
This is the equivalent of RequiresMountsFor=, but adds Wants= instead
of Requires=. It will be useful for example for the autogenerated
systemd-cryptsetup units.
Fixes https://github.com/systemd/systemd/issues/11646
This is preparation for #28891, which adds a bunch more helpers around
"struct iovec", at which point this really deserves its own .c/.h file.
The idea is that we sooner or later can consider "struct iovec" as an
entirely generic mechanism to reference some binary blob, and is the
go-to type for this purpose whenever we need one.
We generally prefer dealing with parsed data instead of original
strings, do so for the "rwm" strings too. We have to convert this to
flags for the primary backend implementation (BPF) anyway, hence we
can do this early to have simpler, shorter and more normalized code.
They add settings to a CGroupContext, hence give them the expected
context, to make clear they do not operate on anything else than the
structure (i.e. not on a kernel cgroup or so).
Almost all our enums/structs/funcs carry the CGroup prefix if they are
defined in cgroup.h, TasksMax so far does not, even though it is
exclusively used in cgroup context.
Change that.
New directive `NFTSet=` provides a method for integrating dynamic cgroup IDs
into firewall rules with NFT sets. The benefit of using this setting is to be
able to use control group as a selector in firewall rules easily and this in
turn allows more fine grained filtering. Also, NFT rules for cgroup matching
use numeric cgroup IDs, which change every time a service is restarted, making
them hard to use in systemd environment.
This option expects a whitespace separated list of NFT set definitions. Each
definition consists of a colon-separated tuple of source type (only "cgroup"),
NFT address family (one of "arp", "bridge", "inet", "ip", "ip6", or "netdev"),
table name and set name. The names of tables and sets must conform to lexical
restrictions of NFT table names. The type of the element used in the NFT filter
must be "cgroupsv2". When a control group for a unit is realized, the cgroup ID
will be appended to the NFT sets and it will be be removed when the control
group is removed. systemd only inserts elements to (or removes from) the sets,
so the related NFT rules, tables and sets must be prepared elsewhere in
advance. Failures to manage the sets will be ignored.
If the firewall rules are reinstalled so that the contents of NFT sets are
destroyed, command systemctl daemon-reload can be used to refill the sets.
Example:
```
table inet filter {
...
set timesyncd {
type cgroupsv2
}
chain ntp_output {
socket cgroupv2 != @timesyncd counter drop
accept
}
...
}
```
/etc/systemd/system/systemd-timesyncd.service.d/override.conf
```
[Service]
NFTSet=cgroup:inet:filter:timesyncd
```
```
$ sudo nft list set inet filter timesyncd
table inet filter {
set timesyncd {
type cgroupsv2
elements = { "system.slice/systemd-timesyncd.service" }
}
}
```
This adds a new structure UnitDefaults which embedds the various default
settings for units we maintain. We so far maintained two sets of
variables for this, one in main.c as static variables and one in the
Manager structure. This moves them into a common structure.
This is most just search/replace, i.e. very dumb refactoring.
The fact that we now use a common structure for this allows us further
refactorings later.
Inspired by the discussions on #27890
seccomp-util.h doesn't need ifdeffing, hence don't. It has worked since
quite a while with HAVE_SECCOMP is off, hence use it everywhere.
Also drop explicit seccomp.h inclusion everywhere (which needs
HAVE_SECCOMP ifdeffery everywhere). seccomp-util.h includes it anyway,
automatically, which we can just rely on, and it deals with HAVE_SECCOMP
at one central place.
When this option is set to direct, the service restarts without entering a failed
state. Dependent units are not notified of transitory failure.
This is useful for the following use case:
We have a target with Requires=my-service, After=my-service.
my-service.service is a oneshot service and has Restart=on-failure in
its definition.
my-service.service can get stuck for various reasons and time out, in
which case it is restarted. Currently, when it fails the first time, the
target fails, even though my-service is restarted.
The behavior we're looking for is that until my-service is not restarted
anymore, the target stays pending waiting for my-service.service to
start successfully or fail without being restarted anymore.
Let's restrict how we apply credential globbing in ImportCredential=, so
that we have some flexibility in automatically extending the glob
expression with per-instance data eventually without getting into
conflict with the globbing parts.
In our current uses we only allow globbing at the end of the expression,
and this is a new, unreleased feature hence let's be restrictive on this
initially. We can still relax this later if we feel the need to after
all.
Fixes: #28022
ImportCredential= takes a credential name and searches for a matching
credential in all the credential stores we know about it. It supports
globs which are expanded so that all matching credentials are loaded.
This implements a minimal subset of #24961, but in a lot more
restrictive way: we only allow one level of subcgroup (as that's enough
to address the no-processes in inner cgroups rule), and does not change
anything about threaded cgroup logic or similar, or make any of this new
behaviour mandatory.
All this does is this: all non-control processes we invoke for a unit
we'll invoke in a subgroup by the specified name.
We'll later port all our current services that use cgroup delegation
over to this, i.e. user@.service, systemd-nspawn@.service and
systemd-udevd.service.
Oftentimes it is useful to allow the per-service fd store to survive
longer than for a restart. This is useful in various scenarios:
1. An fd to some security relevant object needs to be stashed somewhere,
that should not be cleaned automatically, because the security
enforcement would be dropped then.
2. A user namespace fd should be allocated on first invocation and be
kept around until the user logs out (i.e. systemd --user ends), á la
#16328 (This does not implement what #16318 asks for, but should
solve the use-case discussed there.)
3. There's interest in allow a concept of "userspace reboots" where the
kernel stays running, and userspace is swapped out (i.e. all services
exit, and the rootfs transitioned into a new version of it) while
keeping some select resources pinned, very similar to how we
implement a switch root. Thus it is useful to allow services to exit,
while leaving their fds around till the very end.
This is exposed through a new FileDescriptorStorePreserve= setting that
is closely modelled after RuntimeDirectoryPreserve= (in fact it reused
the same internal type), since we want similar behaviour in the end, and
quite often they probably want to be used together.
Correct what appears to be a copy/paste error in config_parse_exec_coredump_filter that is preventing the coredump_filter setting from working correctly.
ExecContext has a field that controls the mount propagation flag of the
mounts in the resulting namespace. This is exposed as "MountFlags="
which is super confusing, as it suggests one could control more than
propagation, and that it was actually a flags field. It's an enum
though only, and nothing else.
We might want to rename this externally one day, but given the compat
kludges this requires and the fact this is somewhat nichey it might not
be worth it. But internally let's rename it, as it makes things much
easier to grok, in particular as part of the codebase already exposed
the concept as mount_propagation_flag.
No actual code flow changes, just some renaming.
In various tools and services we have a per-system and per-user concept.
So far we sometimes used a boolean indicating whether we are in system
mode, or a reversed boolean indicating whether we are in user mode, or
the LookupScope enum used by the lookup path logic.
Let's address that, in introduce a common enum for this, we can use all
across the board.
This is mostly just search/replace, no actual code changes.
This enables the ManagerEnvironment= settings in the user's user.conf to
reference some user data like $HOME for the purpose of setting
environment variables derived from these values.
We should be more careful with distinguishing the cases "all bits set in
caps mask" from "cap mask invalid". We so far mostly used UINT64_MAX for
both, which is not correct though (as it would mean
AmbientCapabilities=~0 followed by AmbientCapabilities=0) would result
in capability 63 to be set (which we don't really allow, since that
means unset).
Mike Yuan
Yu Watanabe
Lennart Poettering
networkException
Alan Liang
Luca Boccassi
Topi Miettinen
David Tardon
Richard Phibel
Daan De Meyer
Jordan Rome
David Schroeder
Zbigniew Jędrzejewski-Szmek
Ronan Pigott