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.
If someone reads /run/host/os-release at the exact same time it is being updated, and it
is large enough, they might read a half-written file. This is very unlikely as
os-release is typically small and very rarely changes, but it is not
impossible.
Bind mount a staging directory instead of the file, and symlink the file
into into, so that we can do atomic file updates and close this gap.
Atomic replacement creates a new inode, so existing bind mounts would
continue to see the old file, and only new services would see the new file.
The indirection via the directory allows to work around this, as the
directory is fixed and never changes so the bind mount is always valid,
and its content is shared with all existing services.
Fixes https://github.com/systemd/systemd/issues/28794
Follow-up for 3f37a82545
exec_child() is supposed to set *exit_status when returning failure.
Unfortunately, we didn't do that in two cases. The result would be:
- a bogus error message "Failed at step SUCCESS spawning foo: …",
- a bogus success exit status.
Bugs introduced in 390902012c and
ad21e542b2.
The code is reworked to add some asserts and not set exit_status in the caller
so that it's clearer (also to the compiler) that it needs to be set.
For a userns root user to be able to access the credentials, both
the uid and gid of the credentials directory have to be mapped into
the userns. Currently, the credentials directory group is root, which
we obviously do not want to map in to a userns, so let's make sure
that the credentials directory and files are owned by the service
group instead, which can generally be safely mapped into the userns.
Since we use permissions mode 0600, this shouldn't cause any change
in who is able to access the credentials.
Fixes#28747
Given that ERRNO_IS_PRIVILEGE() also matches positive values,
make sure this macro is not called with arguments that do not have
errno semantics.
In this case the arguments passed to ERRNO_IS_PRIVILEGE() are the values
returned by set_oom_score_adjust() and set_coredump_filter() which are
not expected to return any positive values, but let's be consistent
anyway and move the ERRNO_IS_PRIVILEGE() invocations to the branches
where the return values are known to be negative.
Currently for portable services we automatically add a bind mount
os-release -> /run/host/os-release. This becomes problematic for the
soft-reboot case, as it's likely that portable services will be configured
to survive it, and thus would forever keep a reference to the old host's
os-release, which would be a problem because it becomes outdated, and also
it stops the old rootfs from being garbage collected.
Create a copy when the manager starts under /run/systemd/propagate instead,
and bind mount that for all services using RootDirectory=/RootImage=, so
that on soft-reboot the content gets updated (without creating a new file,
so the existing bind mounts will see the new content too).
This expands the /run/host/os-release protocol to more services, but I
think that's a nice thing to have too.
Closes https://github.com/systemd/systemd/issues/28023
When systemd-firstboot (or any other unit which uses the tty) is started,
systemd will reset the terminal. If systemd-vconsole-setup happens to be
running at that time, it'll error out when it tries to use the vconsole fd and
gets an EIO from ioctl.
e019ea738d was the first fix. It added an
implicit ordering between units using the tty and systemd-vconsole-setup.
(The commit title is wrong. The approach was generalized, but the commit title
wasn't updated.)
Then cea32691c3 was added to restart
systemd-vconsole-setup.service from systemd-firstboot.service. This was OK,
with the ordering in place, systemd-vconsole-setup.service would wait until
systemd-firstboot.service exited. But this wasn't enough, because we want the
key mappings to be loaded immediately after systemd-firstboot writes the
config. 8eb668b9ab implemented that, but actually
reintroduced the original issue. I had to drop the ordering between the two
units because otherwise we'd deadlock, waiting from firstboot for
vconsole-setup which wouldn't start while firstboot was running.
Restarting vconsole-setup.service from systemd-firstboot.service works just
fine, but when vconsole-setup.service is started earlier, it may be interrupted
by systemd-firstboot.service.
To resolve the issue, let's take a lock around the tty device. The reset is
performed after fork, so the (short) delay should not matter too much.
In xopenat_lock() the assert on <path> is dropped so that we can call
xopenat(fd, NULL) to get a copy of the original fd.
Fixes#26908.
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 add two new helpers: mount_credentials_fs() and
credentials_fs_mount_flags(). The former mounts a file system suitable
for storing of unencrypted credentials at runtime (i.e. a ramfs or
tmpfs). The latter determines the right mount flags to use for such a
mount.
Both functions mostly just take code from execute.c, but make two
changes:
1. If the kernel supports it we'll use a tmpfs with the new "noswap"
mount option instead of ramfs. Was added in kernel 6.4, hence is very
recent, but tmpfs is so much less crappy than ramfs, hence worth it.
2. We'll set MS_NOSYMFOLLOW on the mounts if supported. These file
systems should only contain regulra files, hence no need to allow
symlinks.
When the credential dir is backed by an fs that supports ACLs we must be
more careful with adjusting the 'x' bit of the directory, as any chmod()
call on the dir will reset the mask entry of the ACL entirely which we
don't want. Hence, do a manual set of ACL changes, that only add/drop
the 'x' bit but otherwise leave the ACL as it is.
This matters if we use tmpfs rather than ramfs to store credentials.
This adds support for the new XDG_STATE_HOME env var that was added to
the xdg basedir spec. Previously, because the basedir spec didn't know
the concept we'd alias the backing dir for StateDirectory= to the one
for ConfigurationDirectory= when runnin in --user mode. With this change
we'll make separate. This brings us various benefits, such as proper
"systemctl clean" support, where we can clear service state separately
from service configuration, now in user mode too.
This does not come without complications: retaining compatibility with
older setups is difficult, because we cannot possibly identitfy which
files in existing populated config dirs are actually "state" and which
one are true" configuration.
Hence let's deal with this pragmatically: if we detect that a service
that has both dirs configured only has the configuration dir existing,
then symlink the state dir to the configuration dir to retain
compatibility.
This is not great, but it's the only somewhat reasonable way out I can
see.
Fixes: #25739
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.
When resolving environment variables we currently silently resolve unset
and invalid environment variables to empty strings. Let's do this
slightly less silently: log about unset and invalid env vars, but still
resolve them to an empty string.
Fixes: #27036
Somehow the Linux kernel allows us to allocate a network namespace if we
possess CAP_SYS_ADMIN but doesn't allow us to configure it, unless we
also have CAP_NET_ADMIN.
Taking that into consideration let's avoid allocating a network
namespace we cannot even configure "lo" in.
This is common case if nspawn is invoked without userns and without
netns, because in that case it will have CAP_SYS_ADMIN but no
CAP_NET_ADMIN.
This also takes down a notch the messages about the automatic
downgrading. These have been LOG_WARNING so far, and I downgraded them
to LOG_NOTICE, since in an environment where CAP_NET_ADMIN is not
available this is really not something to be concerned about, but still
noticable. With that it's still more priorized than regular LOG_INFO.
Fixes: #27292
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.
Let's reduce the argument count of setup_namespace() a bit by loading
the sidecar verity settings in apply_mount_namespace(). This will also
make it possible to pass file descriptors to the root image/directory
into setup_namespace() as before this wasn't possible because the
verity settings logic looks for sidecar files next to the
root image which requires the path to be available.
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.
This is closely related to the previous commit: if the credentials dir
is empty and nothing mounted on it, let's remove it again.
This will in particular happen if we decided to not actually install the
mount we prepared for the credentials because it is empty. In that case
the mount point inode is already there, and with this we'll remove it.
Primary effect, users will see ENOENT rather than EACCESS when trying to
access it, which should be preferable, given we already handle that
nicely in our credential consumption code.
This should also be useful on systems where we lack any privs to create
mounts, and thus operate on a regular dir anyway.
Let's avoid creating another mount in the system if it's empty anyway.
This is mostl a cosmetic thing in one (pretty common) special case: if
creds settings are used in a unit but no creds actually available to be
passed.
(While we are at it this also does one more minor optimization: it
adjusts the MS_RDONLY/MS_NOSUID/… flags of the source mount we are about
to MS_MOVE into the right place only if we actually really move it, and
if we instead unmount it again we won't bother with the flags either)
If we create a subcroup (regardless if the '.control' subgroup we
always created or one configured via DelegateSubgroup=) it's inside of
the delegated territory of the cgroup tree, hence it should be owned
fully by the unit's users. Hence do so.
We don't need to apply the journal/oomd xattrs to the subcgroups we add,
since those daemons already look for the xattrs up the tree anyway.
Hence remove this.
This is in particular relevant as it means later changes to the xattr
don#t need to be replicated on the subcgroup either.
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.
Enabling these options when not running as root requires a user
namespace, so implicitly enable PrivateUsers=.
This has a side effect as it changes which users are visible to the unit.
However until now these options did not work at all for user units, and
in practice just a handful of user units in Fedora, Debian and Ubuntu
mistakenly used them (and they have been all fixed since).
This fixes the long-standing confusing issue that the user and system
units take the same options but the behaviour is wildly (and sometimes
silently) different depending on which is which, with user units
requiring manually specifiying PrivateUsers= in order for sandboxing
options to actually work and not be silently ignored.
Yu Watanabe
Lennart Poettering
David Tardon
Luca Boccassi
Zbigniew Jędrzejewski-Szmek
Daan De Meyer
Khem Raj
Dmitry V. Levin
Frantisek Sumsal
Haochen Tong
Stefan Roesch