This geneally makes sense as setting up a PAM session pretty much
defines what a login session is.
In context of #30547 this has the benefit that we can take benefit of
the SetLoginEnvironment= effect without having to set it explicitly,
thus retaining some compat of the uid0 client towards older systemd
service managers.
This combines exec_context_determine_tty_size() and
terminal_set_size_fd() since we always use one after the other.
Also make exec_context_determine_tty_size() return void, since it cannot
fail.
No functional changes, only moving code that is only needed in
exec_invoke, and adding new dependencies for seccomp/selinux/apparmor/pam
in meson for the sd-executor binary.
Currently we spawn services by forking a child process, doing a bunch
of work, and then exec'ing the service executable.
There are some advantages to this approach:
- quick: we immediately have access to all the enourmous amount of
state simply by virtue of sharing the memory with the parent
- easy to refactor and add features
- part of the same binary, will never be out of sync
There are however significant drawbacks:
- doing work after fork and before exec is against glibc's supported
case for several APIs we call
- copy-on-write trap: anytime any memory is touched in either parent
or child, a copy of that page will be triggered
- memory footprint of the child process will be memory footprint of
PID1, but using the cgroup memory limits of the unit
The last issue is especially problematic on resource constrained
systems where hard memory caps are enforced and swap is not allowed.
As soon as PID1 is under load, with no page out due to no swap, and a
service with a low MemoryMax= tries to start, hilarity ensues.
Add a new systemd-executor binary, that is able to receive all the
required state via memfd, deserialize it, prepare the appropriate
data structures and call exec_child.
Use posix_spawn which uses CLONE_VM + CLONE_VFORK, to ensure there is
no copy-on-write (same address space will be used, and parent process
will be frozen, until exec).
The sd-executor binary is pinned by FD on startup, so that we can
guarantee there will be no incompatibilities during upgrades.
Before this commit, $USER, $HOME, $LOGNAME and $SHELL are only
set when User= is set for the unit. For system service, this
results in different behaviors depending on whether User=root is set.
$USER always makes sense on its own, so let's set it unconditionally.
Ideally $HOME should be set too, but it causes trouble when e.g. getty
passes '-p' to login(1), which then doesn't override $HOME. $LOGNAME and
$SHELL are more like "login environments", and are generally not
suitable for system services. Therefore, a new option SetLoginEnvironment=
is also added to control the latter three variables.
Fixes#23438
Replaces #8227
This reverts commit e019ea738d.
In the new approach, a lock on /dev/console will be used. This lock will solve
the issue for services which run in early boot. Services which run later are
ordered after sysinit.target, so they'll run much later anyway so this
automatic dependency is not useful. Let's remove it again to make the code
simpler.
Let's decouple execute.c a bit from the Manager object, let's pass the
runtime scope (i.e. the enum that discern invocation for user or system
context) as part of ExecParameters. This makes the scope available in
various functions without having to pass the Manager object in.
This setting allows services to run in an ephemeral copy of the root
directory or root image. To make sure the ephemeral copies are always
cleaned up, we add a tmpfiles snippet to unconditionally clean up
/var/lib/systemd/ephemeral. To prevent in use ephemeral copies from
being cleaned up by tmpfiles, we use the newly added COPY_LOCK_BSD
and BTRFS_SNAPSHOT_LOCK_BSD flags to take a BSD lock on the ephemeral
copies which instruct tmpfiles to not touch those ephemeral copies as
long as the BSD lock is held.
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 adds support for KSM (kernel samepage merging). It adds a new
boolean parameter called MemoryKSM to enable the feature. The feature
can only be enabled with newer kernels.
The goal of this change is to delay getty services until after
systemd-vconsole-setup has finished. systemd-vconsole-setup starts loadkeys,
and it seems that when loadkeys is interrupted by the TTY hangup call we do
when starting tty services [1], so that loadkeys starts getting EIO from the
ioctl("/dev/tty1", KDSKBENT) syscall it does.
Fixes#26908.
[1] https://github.com/legionus/kbd/issues/92#issuecomment-1554451788
Initially I wanted to add ordering dependencies to individual units, but
TTYVHangup= can be added to other various external units too. The solution with
an implicit dependency should cover those cases too.
Now that we have a potentially pinned fdstore let's add a concept for
cleaning it explicitly on user requested. Let's expose this via
"systemctl clean", i.e. the same way as user directories are cleaned.
Currently, exec runtimes can be shared between units (using
JoinsNamespaceOf=). Let's introduce a concept of a private exec
runtime that isn't shared with JoinsNamespaceOf=. The existing
ExecRuntime struct is renamed to ExecRuntimeShared and becomes a
private member of the new private ExecRuntime.
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.
Unit that requires its own mount namespace creates a temporary directory
to implement dynamic bind mounts (org.freedesktop.systemd1.Manager.BindMountUnit).
However, this directory is never removed and they will accumulate for
each unique unit (e.g. templated units of systemd-coredump@).
Attach the auxiliary runtime directory existence to lifetime of other
"runtime" only per-unit directories.
Define new unit parameter (LogFilterPatterns) to filter logs processed by
journald.
This option is used to store a regular expression which is carried from
PID1 to systemd-journald through a cgroup xattrs:
`user.journald_log_filter_patterns`.
The very basic functinality of StateDirectory= or friends is creating
specified directories. That should work if one entry is a subdirectory
of another. However, it does not when combined with DynamicUser=yes.
To support such case, this adds ExecDirectoryItem.only_create flag, and
if it is set PID1 only create private directory, and not create the symlink
to the private directory.
Fixes#24783.
This reverts PR #22587 and its follow-up commit. More specifically,
2299b1cae3 (partially),
e176f855278d5098d3fecc5aa24ba702147d42e0,
ceb46a31a01b3d3d1d6095d857e29ea214a2776b, and
51bb9076ab8c050bebb64db5035852385accda35.
The PR was merged without final approval, and has several issues:
- OSS fuzz reported issues in the conf parser,
- It calls synchrnous netlink call, it should not be especially in PID1,
- The importance of NFTSet for CGroup and DynamicUser may be
questionable, at least, there was no justification PID1 should support
it.
- For networkd, it should be implemented with Request object,
- There is no test for the feature.
Fixes#23711.
Fixes#23717.
Fixes#23719.
Fixes#23720.
Fixes#23721.
Fixes#23759.
New directive `DynamicUserNFTSet=` provides a method for integrating
configuration of dynamic users into firewall rules with NFT sets.
Example:
```
table inet filter {
set u {
typeof meta skuid
}
chain service_output {
meta skuid != @u drop
accept
}
}
```
```
/etc/systemd/system/dunft.service
[Service]
DynamicUser=yes
DynamicUserNFTSet=inet:filter:u
ExecStart=/bin/sleep 1000
[Install]
WantedBy=multi-user.target
```
```
$ sudo nft list set inet filter u
table inet filter {
set u {
typeof meta skuid
elements = { 64864 }
}
}
$ ps -n --format user,group,pid,command -p `pgrep sleep`
USER GROUP PID COMMAND
64864 64864 55158 /bin/sleep 1000
```
This adds support for searching for credentials more comprehensively.
Specifically, unless an absolute source path is specified we'll now
search for the credentials in the system credentials first, and then in
/etc/credstore/, /run/credstore/, and /usr/lib/credstore, making these
dirs hence the recommended place for credentials to leave in the system.
For LoadCredentialEncrypted= we'll also look into
/etc/credstore.encrypted/, /run/credstore.encrypted/, …. These dirs are
hence suitable for credentials whose provenience isn't trusted (e.g.
UEFI creds from systemd-stub), and thus require to be authenticated
before use.
There's currently a deadlock between PID 1 and dbus-daemon: in some
cases dbus-daemon will do NSS lookups (which are blocking) at the same
time PID 1 synchronously blocks on some call to dbus-daemon. Let's break
that by setting SYSTEMD_NSS_DYNAMIC_BYPASS=1 env var for dbus-daemon,
which will disable synchronously blocking varlink calls from nss-systemd
to PID 1.
In the long run we should fix this differently: remove all synchronous
calls to dbus-daemon from PID 1. This is not trivial however: so far we
had the rule that synchronous calls from PID 1 to the dbus broker are OK
as long as they only go to interfaces implemented by the broke itself
rather than services reachable through it. Given that the relationship
between PID 1 and dbus is kinda special anyway, this was considered
acceptable for the sake of simplicity, since we quite often need
metadata about bus peers from the broker, and the asynchronous logic
would substantially complicate even the simplest method handlers.
This mostly reworks the existing code that sets SYSTEMD_NSS_BYPASS_BUS=
(which is a similar hack to deal with deadlocks between nss-systemd and
dbus-daemon itself) to set SYSTEMD_NSS_DYNAMIC_BYPASS=1 instead. No code
was checking SYSTEMD_NSS_BYPASS_BUS= anymore anyway, and it used to
solve a similar problem, hence it's an obvious piece of code to rework
like this.
Issue originally tracked down by Lukas Märdian. This patch is inspired
and closely based on his patch:
https://github.com/systemd/systemd/pull/22038Fixes: #15316
Co-authored-by: Lukas Märdian <slyon@ubuntu.com>
Add a new setting that follows the same principle and implementation
as ExtensionImages, but using directories as sources.
It will be used to implement support for extending portable images
with directories, since portable services can already use a directory
as root.
When a service exits and triggers either an OnFailure= or OnSuccess=
dependency we now set a new environment variable for the ExecStart= and
ExecStartPre= process. This variable $MONITOR_METADATA exposes the
metadata relating to the service which triggered the dependency.
MONITOR_METADATA takes the following form:
MONITOR_METADATA="SERVICE_RESULT=<result-string0>,EXIT_CODE=<exit-code0>,EXIT_STATUS=<exit-status0>,INVOCATION_ID=<id>,UNIT=<triggering-unit0.service>;SERVICE_RESULT=<result-stringN>,EXIT_CODE=<exit-codeN>,=EXIT_STATUS=<exit-statusN>,INVOCATION_ID=<id>,UNIT=<triggering-unitN.service>"
MONITOR_METADATA is space separated set of metadata relating to the
service(s) which triggered the dependency. This is a list since if we
have 2 services which trigger the same dependency then the dependency
start job may be merged. In this case we need to pass both service
metadata to the triggered service. If there is no job merging then
MONITOR_METADATA will be a single entry.
For example, in the case we had a service "failer.service" which
triggers "failer-handler.service", the following variable is exported to
the ExecStart= and ExecStartPre= processes in failer-handler.service:
MONITOR_METADATA="SERVICE_RESULT=exit-code,EXIT_CODE=exited,EXIT_STATUS=1,INVOCATION_ID=67c657ed7b34466ea369abdf994c6393,UNIT=failer.service"
In another example where we have failer.service and failer2.service
which both also trigger failer-handler.service then the start job for
failer-handler.service may be merged and we might get the following:
MONITOR_METADATA="SERVICE_RESULT=exit-code,EXIT_CODE=exited,EXIT_STATUS=1,INVOCATION_ID=16a93ad196c94109990fb8b9aa5eef5f,UNIT=failer.service;SERVICE_RESULT=exit-code,EXIT_CODE=exited,EXIT_STATUS=1,INVOCATION_ID=ff70131e4cc145e994fb621de25a3e8f,UNIT=failer2.service"
When combined with a tmpfs on /run or /var/lib, allows to create
arbitrary and ephemeral symlinks for StateDirectory or RuntimeDirectory.
This is especially useful when sharing these directories between
different services, to make the same state/runtime directory 'backend'
appear as different names to each service, so that they can be added/removed
to a sharing agreement transparently, without code changes.
An example (simplified, but real) use case:
foo.service:
StateDirectory=foo
bar.service:
StateDirectory=bar
foo.service.d/shared.conf:
StateDirectory=
StateDirectory=shared:foo
bar.service.d/shared.conf:
StateDirectory=
StateDirectory=shared:bar
foo and bar use respectively /var/lib/foo and /var/lib/bar. Then
the orchestration layer decides to stop this sharing, the drop-in
can be removed. The services won't need any update and will keep
working and being able to store state, transparently.
To keep backward compatibility, new DBUS messages are added.
It attaches the LSM BPF program when the system manager starts up.
It populates the hash of maps BPF map when services that have
RestrictFileSystems= set start.
It cleans up the hash of maps when the unit cgroup is pruned.
To pass the file descriptor of the BPF map we add it to the keep_fds
array.
Mike Yuan
Luca Boccassi
Lennart Poettering
Daan De Meyer
Yu Watanabe
Zbigniew Jędrzejewski-Szmek
Stefan Roesch
Michal Koutný
Richard Phibel
Quentin Deslandes
Topi Miettinen
Luca Boccassi
Peter Morrow
Iago Lopez Galeiras