suid binaries and device nodes should not be placed there, hence forbid
it.
Of all the API VFS we mount from PID 1 or via a unit file this one is
the only one where we didn't add MS_NODEV/MS_NOSUID. Let's address that,
since there's really no reason why device nodes or suid binaries would
be placed in hugetlbfs.
When adding a sysext image to the system and manuall merging it, a
later "systemctl (re)start systemd-sysext" won't work because "merge"
refuses to work when something is merged already. Another problem with
"merge" at start plus "unmerge" at stop is that a service restart can't
make use of the new MOVE_MOUNT_BENEATH in the future even which would
only be available in "refresh". It also prepares us for setting up the
merged overlay for the sysroot from the initrd already, which also
would lead to the mentioned start problem of the service (One
optimization could be to skip the loading but only if we are sure that
all images were loaded and weren't modified since - this assumption is
hard because early services could want to inject a sysext, too).
Use "refresh" on service start to fix the problem that the service
can't start as soon as a manual merge was done. Also add a reload
action that allows to issue "systemctl reload systemd-sysext" and it
will make use of MOVE_MOUNT_BENEATH once we implement this in
systemd-sysext refresh (and it's available from the kernel).
sysexts are meant to extend /usr. All extension images and directories are opened and merged in a
single, read-only overlayfs layer, mounted on /usr.
So far, we had fallback storage directories in /usr/lib/extensions and /usr/local/lib/extensions.
This is problematic for three reasons.
Firstly, technically, for directory-based extensions the kernel will reject
creating such an overlay, as there is a recursion problem. It actively
validates that a lowerdir is not a child of another lowerdir, and fails with
-ELOOP if it is. So having a sysext /usr/lib/extensions/myextdir/ would result
in an overlayfs config lowerdir=/usr/lib/extensions/myextdir/usr/:/usr which is
not allowed, as indicated by Christian the kernel performs this check:
/*
* Check if this layer root is a descendant of:
* - another layer of this overlayfs instance
* - upper/work dir of any overlayfs instance
*/
<...>
/* Walk back ancestors to root (inclusive) looking for traps */
while (!err && parent != next) {
if (is_lower && ovl_lookup_trap_inode(sb, parent)) {
err = -ELOOP;
pr_err("overlapping %s path\n", name);
Secondly, there's a confusing aspect to this recursive storage. If you
have /usr/lib/extensions/myext.raw which contains /usr/lib/extensions/mynested.raw
'systemd-sysext merge' will only pick up the first one, but both will appear in
the merged root under /usr/lib/extensions/. So you have two extension images, both
appear in your merged filesystem, but only one is actually in use.
Finally, there's a conceptual aspect: the idea behind sysexts and hermetic /usr
is that the /usr tree is not modified locally, but owned by the vendor. Dropping
extensions in /usr thus goes contrary to this foundational concept.
It's a bit nicer if we only write the sysctl core_pattern once the
coredump socket is established, since it's the backend for the handler.
Given the systemd-coredump.socket basically has no dependencies that run
before it this should not really make things slower or so, it just
removes the tiny window where core pattern is in effect that wants to
connect to the backend socket but cannot.
The status quo isn't terrible, and not too different in effect: either
way, until the socket unit is up we won't process coredumps. It's mostly
what kind of behaviour you get then: an error due to /bin/false being
invoked, or an error because systemd-coredump can't connect to its
socket. After this patch we'll exclusively see the former.
The user manager connects to oomd over varlink. Currently, during
shutdown, if oomd is stopped before any user manager, the user
manager will try to reconnect to the socket, leading to a warning
from pid 1 about a conflicting transaction.
Let's fix this by ordering user@.service after systemd-oomd.service,
so that user sessions are stopped before systemd-oomd is stopped,
which makes sure that the user sessions won't try to start oomd via
its socket after systemd-oomd is stopped.
Let's color output when we're forwarding to the console. To make this
work, we inherit TERM from pid 1 and use it to decide whether we should
output colors or not.
This drops all mentions of gnu-efi and its manual build machinery. A
future commit will bring bootloader builds back. A new bootloader meson
option is now used to control whether to build sd-boot and its userspace
tooling.
Let's make things systematic: the per-user and the per-system manager
should manage their own memory pressure, as they are, well, managers of
things.
This is particularly relevant and the per-user service manager should
watch its own "init.scope" subcgroup, instead of the main service unit
cgroup, and hence $MEMORY_PRESSURE_WATCH as set by the per-system
service manager would simply be wrong.
These units are also present in the initrd, so instead of an assert,
just use a condition so they are skipped where they need to be skipped.
Fixes https://github.com/systemd/systemd/issues/26358
Config options are -Ddefault-timeout-sec= and -Ddefault-user-timeout-sec=.
Existing -Dupdate-helper-user-timeout= is renamed to -Dupdate-helper-user-timeout-sec=
for consistency. All three options take an integer value in seconds. The
renaming and type-change of the option is a small compat break, but it's just
at compile time and result in a clear error message. I also doubt that anyone was
actually using the option.
This commit separates the user manager timeouts, but keeps them unchanged at 90 s.
The timeout for the user manager is set to 4/3*user-timeout, which means that it
is still 120 s.
Fedora wants to experiment with lower timeouts, but doing this via a patch would
be annoying and more work than necessary. Let's make this easy to configure.
since we don't have systemd-pcrphase built anyway, which breaks the tests:
...
I: Attempting to install /usr/lib/systemd/systemd-networkd-wait-online (based on unit file reference)
I: Attempting to install /usr/lib/systemd/systemd-network-generator (based on unit file reference)
I: Attempting to install /usr/lib/systemd/systemd-oomd (based on unit file reference)
I: Attempting to install /usr/lib/systemd/systemd-pcrphase (based on unit file reference)
W: Failed to install '/usr/lib/systemd/systemd-pcrphase'
make: *** [Makefile:4: setup] Error 1
make: Leaving directory '/root/systemd/test/TEST-01-BASIC'
Follow-up to 04959faa63.
The systemd-growfs@.service units are currently written in full for each
file system to grow. Which is kinda pointless given that (besides an
optional ordering dep) they contain always the same definition. Let's
fix that and add a static template for this logic, that the generator
simply instantiates (and adds an ordering dep for).
This mimics how systemd-fsck@.service is handled. Similar to the wait
that for root fs there's a special instance systemd-fsck-root.service
we also add a special instance systemd-growfs-root.service for the root
fs, since it has slightly different deps.
Fixes: #20788
See: #10014
We want PCR 15 to be useful for binding per-system policy to. Let's
measure the machine ID into it, to ensure that every OS we can
distinguish will get a different PCR (even if the root disk encryption
key is already measured into it).
Before this patch the only way to prevent journald from reading the audit
messages was to mask systemd-journald-audit.socket. However this had main
drawback that downstream couldn't ship the socket disabled by default (beside
the fact that masking units is not supposed to be the usual way to disable
them).
Fixes#15777
We are basically already there, just need to add MONOTONIC_USEC= to the
RELOADING=1 message, and make sure the message is generated in really
all cases.
And send READY=1 again when we are done with it.
We do this not only for "daemon-reload" but also for "daemon-reexec" and
"switch-root", since from the perspective of an encapsulating service
manager these three operations are not that different.
This adds the same condition that systemd-networkd.service already
carries also to systemd-networkd-wait-online.service. Otherwise we'll
potentially see some logs we'd rather not see about a service we BindTo=
not running. Or in other words, if service X binds to Y then X should be
at least as conditioned as Y.
Note that this drops ProtectProc=invisible from
systemd-resolved.service.
This is done because othewise access to the booted "kernel" command line is not
necessarily available. That's because in containers we want to read
/proc/1/cmdline for that.
Fixes: #24103
This renames systemd-boot-system-token.service to
systemd-boot-random-seed.service and conditions it less strictly.
Previously, the job of the service was to write a "system token" EFI
variable if it was missing. It called "bootctl --graceful random-seed"
for that. With this change we condition it more liberally: instead of
calling it only when the "system token" EFI variable isn't set, we call
it whenever a boot loader interface compatible boot loader is used. This
means, previously it was invoked on the first boot only: now it is
invoked at every boot.
This doesn#t change the command that is invoked. That's because
previously already the "bootctl --graceful random-seed" did two things:
set the system token if not set yet *and* refresh the random seed in the
ESP. Previousy we put the focus on the former, now we shift the focus to
the latter.
With this simple change we can replace the logic
f913c784ad added, but from a service that
can run much later and doesn't keep the ESP pinned.
We want to make use of that when formatting file systems, hence let's
pull in these modules explicitly.
(This is necessary because we are an early boot service that might run
before systemd-tmpfiles-dev.service, which creates /dev/loop-control and
/dev/mapper/control.)
Alternatively we could just order ourselves after
systemd-tmpfiles-dev.service, but I think there's value in adding an
explicit minimal ordering here, since we know what we'll need.
Fixes: #25775
If everything points to the fact that TPM2 should work, but then the
driver fails to initialize we should handle this gracefully and not
cause failing services all over the place.
Fixes: #25700
We don't want systemd-networkd-wait-online to start if systemd-networkd
is skipped due to condition failures. This is only guaranteed by BindsTo=
and not Requires=, so let's use BindsTo=
sd-stub has an opportunity to handle the seed the same way sd-boot does,
which would have benefits for UKIs when sd-boot is not in use. This
commit wires that up.
It refactors the XBOOTLDR partition discovery to also find the ESP
partition, so that it access the random seed there.
Removing the virtualization check might not be the worst thing in the
world, and would potentially get many, many more systems properly seeded
rather than not seeded. There are a few reasons to consider this:
- In most QEMU setups and most guides on how to setup QEMU, a separate
pflash file is used for nvram variables, and this generally isn't
copied around.
- We're now hashing in a timestamp, which should provide some level of
differentiation, given that EFI_TIME has a nanoseconds field.
- The kernel itself will additionally hash in: a high resolution time
stamp, a cycle counter, RDRAND output, the VMGENID uniquely
identifying the virtual machine, any other seeds from the hypervisor
(like from FDT or setup_data).
- During early boot, the RNG is reseeded quite frequently to account for
the importance of early differentiation.
So maybe the mitigating factors make the actual feared problem
significantly less likely and therefore the pros of having file-based
seeding might outweigh the cons of weird misconfigured setups having a
hypothetical problem on first boot.
Rather than passing seeds up to userspace via EFI variables, pass seeds
directly to the kernel's EFI stub loader, via LINUX_EFI_RANDOM_SEED_TABLE_GUID.
EFI variables can potentially leak and suffer from forward secrecy
issues, and processing these with userspace means that they are
initialized much too late in boot to be useful. In contrast,
LINUX_EFI_RANDOM_SEED_TABLE_GUID uses EFI configuration tables, and so
is hidden from userspace entirely, and is parsed extremely early on by
the kernel, so that every single call to get_random_bytes() by the
kernel is seeded.
In order to do this properly, we use a bit more robust hashing scheme,
and make sure that each input is properly memzeroed out after use. The
scheme is:
key = HASH(LABEL || sizeof(input1) || input1 || ... || sizeof(inputN) || inputN)
new_disk_seed = HASH(key || 0)
seed_for_linux = HASH(key || 1)
The various inputs are:
- LINUX_EFI_RANDOM_SEED_TABLE_GUID from prior bootloaders
- 256 bits of seed from EFI's RNG
- The (immutable) system token, from its EFI variable
- The prior on-disk seed
- The UEFI monotonic counter
- A timestamp
This also adjusts the secure boot semantics, so that the operation is
only aborted if it's not possible to get random bytes from EFI's RNG or
a prior boot stage. With the proper hashing scheme, this should make
boot seeds safe even on secure boot.
There is currently a bug in Linux's EFI stub in which if the EFI stub
manages to generate random bytes on its own using EFI's RNG, it will
ignore what the bootloader passes. That's annoying, but it means that
either way, via systemd-boot or via EFI stub's mechanism, the RNG *does*
get initialized in a good safe way. And this bug is now fixed in the
efi.git tree, and will hopefully be backported to older kernels.
As the kernel recommends, the resultant seeds are 256 bits and are
allocated using pool memory of type EfiACPIReclaimMemory, so that it
gets freed at the right moment in boot.
As in most cases, tty device without input devices is meaningless.
This also swaps the priority of tty and net:
- input devices are often connected under USB bus, hence may take
slightly much time to be initialized. As, described in the above,
in most cases it is allowed that tty devices are initialized just
before input devices,
- network configuration usually requires much time, e.g. DHCP or RA,
hence it is better that network interfaces initialized. Then,
network services can start DHCP client or friends earlier.
Fixes#24026.
This adds two more phases to the PCR boot phase logic: "sysinit" +
"final".
The "sysinit" one is placed between sysinit.target and basic.target.
It's good to have a milestone in this place, since this is after all
file systems/LUKS volumes are in place (which sooner or later should
result in measurements of their own) and before services are started
(where we should be able to rely on them to be complete).
This is particularly useful to make certain secrets available for
mounting secondary file systems, but making them unavailable later.
This breaks API in a way (as measurements during runtime will change),
but given that the pcrphase stuff wasn't realeased yet should be OK.
With this, I can now easily do:
systemd-nspawn --load-credential=ssh.authorized_keys.root:/home/lennart/.ssh/authorized_keys --image=… --boot
To boot into an image with my SSH key copied in. Yay!
