Currently only a single job for a single unit can be enqueued
atomically,
so there is no guarantee that, e.g., starting a unit and its socket
at the same time will happen in the same transaction. That forces
callers to 'know' the right order in which to start new units being
installed, or failures will occur. It also means some ordering
constraints are ignored, in case the separate calls are done
in the wrong manual order.
Add a new EnqueueUnitJobMany() D-Bus method that takes a list of units
to start.
Allow systemd-executor to be compiled into a single binary.
The existing -Dlink-executor-shared=true|false is extended to also
allow -Dlink-executor-shared=single (*). The new mode is opt-in,
to allow experimentation and introduce this smoothly.
This saves a little space, but not as much as I expected:
$ ls -l build/{systemd,systemd-executor} build-new/systemd
-rwxr-xr-x 1 zbyszek zbyszek 631520 May 25 22:44 build/systemd
-rwxr-xr-x 1 zbyszek zbyszek 670464 May 25 22:44 build/systemd-executor
-rwxr-xr-x 1 zbyszek zbyszek 1214488 May 25 22:45 build-new/systemd
(This is with -Dbuildtype=debugoptimized -Db_lto=true).
The combined binary is slightly smaller than the sum of the separate
ones, but not much. In both cases, the binaries are linked to
libsystemd-core which is 10MB, so the size of the binaries themselves
doesn't make much of a difference. The executor needs exec-invoke.c
which is huge and not shared with anything else.
Longer term, I want to allow systemd to be linked statically. In
that case, having systemd-executor separate would be very painful.
So the option to use a multicall binary will be necessary.
Previously, we stored the resolved path to systemd-executor and
used it argv[0]. I don't think this was useful. After all, normally
we would use the non-resolved original path as argv[0]. So that
part is dropped, and the resolved path is only logged, but
"systemd-executor" is always used as argv[0]. This makes the
multicall binary work reliably, no matter what the actual file
name is.
(*) This means that compat as the commandline level is maintained:
'meson setup build -Dlink-executor-shared=true …' works as before.
Unfortunately, when using an existing build directory, meson chokes
on the type change and refuses to reconfigure the directory or change
the option or do anything useful. I think meson is DTWT here, but
this is hard to fix. So the build directory probably needs to be
recreated.
Currently only a single job for a single unit can be enqueued atomically,
so there is no guarantee that, e.g., starting a unit and its socket
at the same time will happen in the same transaction. That forces
callers to 'know' the right order in which to start new units being
installed, or failures will occur. It also means some ordering
constraints are ignored, in case the separate calls are done
in the wrong manual order.
Add a new EnqueueUnitJobMany() D-Bus method that takes a list of units
to start.
Fixes https://github.com/systemd/systemd/issues/8102
Co-authored-by: Michal Koutný <mkoutny@suse.com>
In order to allow FD Stores of user units to survive a user
session restart, propagate FDs received via the protocol up one
level from user to system manager via sd_notify.
And the other way around, propagate them down via LISTEN_FDS
tagging them with the unit name so that the child manager can
inject them in the appropriate unit.
Ensure units that are dead or not loaded can get FDs added to
their stores, and that they are correctly propagated once the
unit is started or loaded. When the unit is not loaded we don't
know what the FD max limit is, so simply increase it for each FD
injected, and then when the unit is realised prune it down to
match the unit's now available config in case the limit is lower
than the number of FDs in the store.
Each FD sent up or down is assigned a monotonic index, and the manager
also sends a JSON map that associates the index with the original
unit and FDNAME:
{
"unit-name.service": [
{ "name": "fdname1", "index": 1 },
{ "name": "fdname2", "index": 2 }
],
...
}
This allows the manager to assign back the FDs to the appropriate
unit using the appropriate name, given the FDNAMEs are not unique.
Add a new RestrictFileSystemAccess= boolean setting in the [Manager] section of
system.conf that enforces execution only from signed dm-verity block
devices and the initramfs during early boot.
When RestrictFileSystemAccess=yes is set, PID1 loads a BPF LSM program early in boot
that:
Integrity tracking (self-populating, no userspace involvement):
- bdev_setintegrity: records dm-verity signature status in a BPF hash
map when the kernel signals device integrity via
security_bdev_setintegrity()
- bdev_free_security: removes devices from the map on teardown
Execution enforcement (deny-default policy):
- bprm_check_security: blocks execve() from untrusted sources
- mmap_file: blocks PROT_EXEC mmap (shared libs, anonymous exec memory)
- file_mprotect: blocks W->X transitions (JIT, libffi, etc.)
Trust anchors:
- Signed dm-verity volumes (sig_valid flag in the BPF map)
- Initramfs (s_dev captured at load time, cleared after switch_root)
- Everything else is denied (tmpfs, procfs, sysfs, anonymous PROT_EXEC)
PID1 requires dm-verity require_signatures=1 to be enabled and refuses
to load the BPF program otherwise, ensuring the kernel enforces that all
dm-verity devices carry valid signatures.
After attach, PID1 extracts owned FDs from the skeleton (link FDs +
.bss map FD) and lets the skeleton be destroyed. The dup'd link FDs
keep programs attached via the kernel reference chain (link FD ->
bpf_link -> bpf_prog -> bpf_map). Destroying the skeleton unmaps the
.bss page from PID1's address space so no BPF state is readable via
/proc/1/mem. The .bss map FD is retained for targeted writes (clearing
initramfs_s_dev after switch_root via mmap).
Signed-off-by: Christian Brauner <brauner@kernel.org>
Let's cap the number of states/patterns per query to something
reasonable, i.e. max 256 states and 4K patterns per query.
---
Also, use the env assignments limit in a couple more places.
Introduce a counter that tracks how many configuration reloads have
been successfully completed by the manager. The increment lives in
manager_reload() right after the "point of no return", so failed
reload attempts that bail out earlier (e.g. during serialization)
do not bump the counter.
It is accessible as a new ReloadCount property to
org.freedesktop.systemd1.Manager (D-Bus) and ReloadCount to
io.systemd.Manager.Describe (Varlink).
Also add an integration test for ReloadCount
that verifies that the new ReloadCount property increments by one per
daemon-reload, accumulates correctly across multiple reloads, and that
D-Bus and Varlink return identical values. Also tests that the counter
reset after a reexec.
Co-developed-by: Claude Opus 4.7 <noreply@anthropic.com>
Signed-off-by: Simon Lucido <simonlucido@meta.com>
Let's introduce these for the following two reasons:
- Using them makes sure the parameter names match between declaration
and definition (if both use the corresponding macros).
- They make sure developers can't forget the _const_ and _pure_
attributes for the declarations.
This commit also includes some include sorting fixes
Preparation for later commits, but I think this one makes
a ton of sense on its own. When debug logging is enabled
it's otherwise difficult to dig up the portion of journal
for transaction construction.
- Make sure forward headers have the iwyu pragma to always keep them
- Make sure we always include the daemon specific forward header
instead of shared-forward.h
- Remove shared-forward.h include where the daemon specific forward
header is already included
Let's not leak details from src/shared and src/libsystemd into
src/basic, even though you can't actually do anything useful with
just forward declarations from src/shared.
The sd-forward.h header is put in src/libsystemd/sd-common as we
don't have a directory for shared internal headers for libsystemd
yet.
Let's also rename forward.h to basic-forward.h to keep things
self-explanatory.
closes#37602
On typical systems, only few services need to create SUID/SGID files.
This often is limited to the user explicitly setting suid/sgid, the
`systemd-tmpfiles*` services, and the package manager. Allowing a default
to globally restrict creation of suid/sgid files makes it easier to apply
this restriction precisely.
Alternative to b50f6dbe57
The commit naively returned early from socket_enter_running(), which however
is quite problematic, as the socket will be woken up over and over again
without doing a thing, until we eventually hit Poll/TriggerLimit*=.
On top of that it requires hacks to hold the start job for initrd-switch-root.service
up. Overall I doubt that is the right approach.
Let's instead hook this into our job engine, and try to activate
the service again when some other units are stopped. If all installed
jobs have been run yet we're still seeing the conflict or the manually
selected timeout is reached, fail the socket as before.
Our baseline is v5.4 and cgroup v2 is enforced now,
which means CPU accounting is cheap everywhere without
requiring any controller, hence just remove the directive.
Currently there are various circular dependencies between headers
in core/. Let's get rid of these by making judicious use of forward
declarations and moving includes into implementation files instead of
having them in header files.
Getting rid of circular header includes simplifies the code and makes
various clang based tooling such as iwyu work much better on our code.
The most important change is getting rid of the manager.h include in
unit.h which is possible thanks to the previous commits. We also move
the OOMPolicy and StatusType enums to unit.h to remove the need for
other unit headers to include manager.h to get access to these enums.
There's no need for these to be fields inside the manager struct,
let's turn them into functions in unit.h instead, again to allow
forward declaring the Manager struct in a later commit.
The PidRefs are in all cases owned by Unit.pids, and gets removed
from Manager.watch_pids(_more) when the unit is destructed, via
unit_unwatch_pidref(). This hasn't caused any issue because
manager_clear_jobs_and_units() is called before destroying
Manager.watch_pids(_more), but let's get this right.
This introduce LOG_ITEM() macro that checks arbitrary formats in
log_struct().
Then, drop _printf_ attribute from log_struct_internal(), as it does not
help so much, and compiler checked only the first format string.
Hopefully, this silences false-positive warnings by Coverity.
This new setting allows unsharing the pid namespace in a unit. Because
you have to fork to get a process into a pid namespace, we fork in
systemd-executor to get into the new pid namespace. The parent then
sends the pid of the child process back to the manager and exits while
the child process continues on with the rest of exec_invoke() and then
executes the actual payload.
Communicating the child pid is done via a new pidref socket pair that is
set up on manager startup.
We unshare the PID namespace right before the mount namespace so we
mount procfs correctly. Note PrivatePIDs=yes always implies MountAPIVFS=yes
to mount procfs.
When running unprivileged in a user session, user namespace is set up first
to allow for PID namespace to be unshared. However, when running in
privileged mode, we unshare the user namespace last to ensure the user
namespace does not own the PID namespace and cannot break out of the sandbox.
Note we disallow Type=forking services from using PrivatePIDs=yes since the
init proess inside the PID namespace must not exit for other processes in
the namespace to exist.
Note Daan De Meyer did the original work for this commit with Ryan Wilson
addressing follow-ups.
Co-authored-by: Daan De Meyer <daan.j.demeyer@gmail.com>
We call similar other fields in main.c (notably: rlimit stuff, env vars) "saved",
rather than "original". Hence stick to that kind of naming here too.
Follow-up for: #32937
Luca Boccassi
Zbigniew Jędrzejewski-Szmek
Luca BoccassiandMichal Koutný
Michal Sekletar
Christian Brauner
Lennart Poettering
Simon Lucido
Frantisek Sumsal
Daan De Meyer
Nikolas Kyx
Yaping Li
Daan De Meyer
Yu Watanabe
Mike Yuan
Grimmauld
Ronan Pigott
Lennart Poettering