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.
After 'if (DEBUG_LOGGING)' is added, the two call sites are almost identical,
except that we forgot LOG_UNIT_INVOCATION_ID(unit).
I removed the handling of the log_oom(). It's a debug message only after all,
and it's unlikely to fail.
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.
Chasing symlinks is a core function that's used in a lot of places
so it deservers a less verbose names so let's rename it to chase()
and chaseat().
We also slightly change the pattern used for the chaseat() helpers
so we get chase_and_openat() and similar.
Whenever we're going to close all file descriptors, we tend to close
the log and set it into open when needed mode. When this is done with
the logging target set to LOG_TARGET_AUTO, we run into issues because
for every logging call, we'll check if stderr is connected to the
journal to determine where to send the logging message. This check
obviously stops working when we close stderr, so we settle the log
target before we do that so that we keep using the same logging
target even after stderr is closed.
Let's allow configuring tty term and size using kernel cmdline arguments
so that when running in a VM we can communicate the terminal TERM and size
from the host via SMBIOS extra kernel cmdline arguments.
The interface requires services to write to the cgroup file to activate notifications,
but with ProtectControlGroups=yes we make it read-only. Add a writable bind mount.
Follow-up for 6bb0084204
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.
On some ARM platforms, the dynamic linker could use PROT_BTI memory protection
flag with `mprotect(..., PROT_BTI | PROT_EXEC)` to enable additional memory
protection for executable pages. But `MemoryDenyWriteExecute=yes` blocks this
with seccomp filter denying all `mprotect(..., x | PROT_EXEC)`.
Newly preferred method is to use prctl(PR_SET_MDWE) on supported kernels. Then
in-kernel implementation can allow PROT_BTI as necessary, without weakening
MDWE. In-kernel version may also be extended to more sophisticated protections
in the future.
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.
If a PAM service sets some ambient caps, we should honour that, hence
query it, and merge it with our own ambient settings.
This needs to be done manually since otherwise dropping privs via
setresuid() will undo all such caps, and we need to manually tweak
things to keep them.
Even when a mount namespace is created, previously host's sysfs is used,
especially with RootDirectory= or RootImage=, thus service processes can
still access the properties of the network interfaces in the main network
namespace through sysfs.
This makes, sysfs is remounted with the new network namespace tag, except
when PrivateMounts= is explicitly disabled. Hence, the properties of the
network interfaces in the main network namespace cannot be accessed by
service processes through sysfs.
Fixes#26422.
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).
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.
-1 was used everywhere, but -EBADF or -EBADFD started being used in various
places. Let's make things consistent in the new style.
Note that there are two candidates:
EBADF 9 Bad file descriptor
EBADFD 77 File descriptor in bad state
Since we're initializating the fd, we're just assigning a value that means
"no fd yet", so it's just a bad file descriptor, and the first errno fits
better. If instead we had a valid file descriptor that became invalid because
of some operation or state change, the other errno would fit better.
In some places, initialization is dropped if unnecessary.
Lennart Poettering
Yu Watanabe
David Tardon
Zbigniew Jędrzejewski-Szmek
Daan De Meyer
Frantisek Sumsal
Luca Boccassi
Topi Miettinen
Michal Koutný
Richard Phibel