This moves pretty much all uses of getpid() over to getpid_raw(). I
didn't specifically check whether the optimization is worth it for each
replacement, but in order to keep things simple and systematic I
switched over everything at once.
This introduces {State,Cache,Log,Configuration}Directory= those are
similar to RuntimeDirectory=. They create the directories under
/var/lib, /var/cache/, /var/log, or /etc, respectively, with the mode
specified in {State,Cache,Log,Configuration}DirectoryMode=.
This also fixes#6391.
Commit 74dd6b515f (core: run each system
service with a fresh session keyring) broke adding keys to user keyring.
Added keys could not be accessed with error message:
keyctl_read_alloc: Permission denied
So link the user keyring to our session keyring.
This patch is a bit more complex thant I hoped. In particular the single
IOScheduling= property exposed on the bus is split up into
IOSchedulingClass= and IOSchedulingPriority= (though compat is
retained). Otherwise the asymmetry between setting props and getting
them is a bit too nasty.
Fixes#5613
'n_fds' field in the ExecParameters structure was counting the total number of
file descriptors to be passed to a unit.
This counter also includes the number of passed socket fds which is counted by
'n_socket_fds' already.
This patch removes that redundancy by replacing 'n_fds' with
'n_storage_fds'. The new field only counts the fds passed via the storage store
mechanism. That way each fd is counted at one place only.
Subsequently the patch makes sure to fix code that used 'n_fds' and also wanted
to iterate through all of them by explicitly adding 'n_socket_fds' + 'n_storage_fds'.
Suggested by Lennart.
Make sure to only apply the O_NONBLOCK flag to the fds passed via socket
activation.
Previously the flag was also applied to the fds which came from the fd store
but this was incorrect since services, after being restarted, expect that these
passed fds have their flags unchanged and can be reused as before.
The documentation was a bit unclear about this so clarify it.
Till now if the params->n_fds was 0, systemd was logging that there were
more than one sockets.
Thanks @gregoryp and @VFXcode who did the most work debugging this.
This doesn't really matter much, only in case somebody would use
something strange like
EnvironmentFile=/etc/something/.*
Make sure that "." and ".." is not returned by that glob. This makes
all our globbing patterns behave the same.
log_struct takes multiple format strings, each one followed by arguments.
The _printf_ annotation is not sufficiently flexible to express this,
but we can still annotate the first format string, though not its
arguments (because their number is unknown).
With the annotation, the places which specified the message id or similar
as the first pattern cause a warning from -Wformat-nonliteral. This can
be trivially fixed by putting the MESSAGE= first.
This change will help find issues where a non-literal is erroneously used
as the pattern.
The MountAPIVFS= documentation says that this options has no effect
unless used in conjunction with RootDirectory= or RootImage= ,lets fix
this and avoid to create private mount namespaces where it is not
needed.
Embedding sd_id128_t's in constant strings was rather cumbersome. We had
SD_ID128_CONST_STR which returned a const char[], but it had two problems:
- it wasn't possible to statically concatanate this array with a normal string
- gcc wasn't really able to optimize this, and generated code to perform the
"conversion" at runtime.
Because of this, even our own code in coredumpctl wasn't using
SD_ID128_CONST_STR.
Add a new macro to generate a constant string: SD_ID128_MAKE_STR.
It is not as elegant as SD_ID128_CONST_STR, because it requires a repetition
of the numbers, but in practice it is more convenient to use, and allows gcc
to generate smarter code:
$ size .libs/systemd{,-logind,-journald}{.old,}
text data bss dec hex filename
1265204 149564 4808 1419576 15a938 .libs/systemd.old
1260268 149564 4808 1414640 1595f0 .libs/systemd
246805 13852 209 260866 3fb02 .libs/systemd-logind.old
240973 13852 209 255034 3e43a .libs/systemd-logind
146839 4984 34 151857 25131 .libs/systemd-journald.old
146391 4984 34 151409 24f71 .libs/systemd-journald
It is also much easier to check if a certain binary uses a certain MESSAGE_ID:
$ strings .libs/systemd.old|grep MESSAGE_ID
MESSAGE_ID=%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x
MESSAGE_ID=%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x
MESSAGE_ID=%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x
MESSAGE_ID=%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x
$ strings .libs/systemd|grep MESSAGE_ID
MESSAGE_ID=c7a787079b354eaaa9e77b371893cd27
MESSAGE_ID=b07a249cd024414a82dd00cd181378ff
MESSAGE_ID=641257651c1b4ec9a8624d7a40a9e1e7
MESSAGE_ID=de5b426a63be47a7b6ac3eaac82e2f6f
MESSAGE_ID=d34d037fff1847e6ae669a370e694725
MESSAGE_ID=7d4958e842da4a758f6c1cdc7b36dcc5
MESSAGE_ID=1dee0369c7fc4736b7099b38ecb46ee7
MESSAGE_ID=39f53479d3a045ac8e11786248231fbf
MESSAGE_ID=be02cf6855d2428ba40df7e9d022f03d
MESSAGE_ID=7b05ebc668384222baa8881179cfda54
MESSAGE_ID=9d1aaa27d60140bd96365438aad20286
ReadOnlyPaths=, ProtectHome=, InaccessiblePaths= and ProtectSystem= are
about restricting access and little more, hence they should be disabled
if PermissionsStartOnly= is used or ExecStart= lines are prefixed with a
"+". Do that.
(Note that we will still create namespaces and stuff, since that's about
a lot more than just permissions. We'll simply disable the effect of
the four options mentioned above, but nothing else mount related.)
This also adds a test for this, to ensure this works as intended.
No documentation updates, as the documentation are already vague enough
to support the new behaviour ("If true, the permission-related execution
options…"). We could clarify this further, but I think we might want to
extend the switches' behaviour a bit more in future, hence leave it at
this for now.
Fixes: #5308
Or actually, try to to do the right thing depending on what is
available:
- If we know $HOME from User=, then use that.
- If the UID for the service is 0, hardcode that WorkingDirectory=~ means WorkingDirectory=/root
- In any other case (which will be the unprivileged --user case), use
get_home_dir() to find the $HOME of the user we are running as.
- Otherwise fail.
Fixes: #5246#5124
This is similar to RootDirectory= but mounts the root file system from a
block device or loopback file instead of another directory.
This reuses the image dissector code now used by nspawn and
gpt-auto-discovery.
This adds a boolean unit file setting MountAPIVFS=. If set, the three
main API VFS mounts will be mounted for the service. This only has an
effect on RootDirectory=, which it makes a ton times more useful.
(This is basically the /dev + /proc + /sys mounting code posted in the
original #4727, but rebased on current git, and with the automatic logic
replaced by explicit logic controlled by a unit file setting)
Before previous commit, username would be NULL for root, and set only
for other users. So the argument passed to utmp_put_init_process()
would be "root" for other users and NULL for root. Seems strange.
Instead, always pass the username if available.
This changes the environment for services running as root from:
LANG=C.utf8
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
INVOCATION_ID=ffbdec203c69499a9b83199333e31555
JOURNAL_STREAM=8:1614518
to
LANG=C.utf8
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
HOME=/root
LOGNAME=root
USER=root
SHELL=/bin/sh
INVOCATION_ID=15a077963d7b4ca0b82c91dc6519f87c
JOURNAL_STREAM=8:1616718
Making the environment special for the root user complicates things
unnecessarily. This change simplifies both our logic (by making the setting
of the variables unconditional), and should also simplify the logic in
services (particularly scripts).
Fixes#5124.
This substantially reworks the seccomp code, to ensure better
compatibility with some architectures, including i386.
So far we relied on libseccomp's internal handling of the multiple
syscall ABIs supported on Linux. This is problematic however, as it does
not define clear semantics if an ABI is not able to support specific
seccomp rules we install.
This rework hence changes a couple of things:
- We no longer use seccomp_rule_add(), but only
seccomp_rule_add_exact(), and fail the installation of a filter if the
architecture doesn't support it.
- We no longer rely on adding multiple syscall architectures to a single filter,
but instead install a separate filter for each syscall architecture
supported. This way, we can install a strict filter for x86-64, while
permitting a less strict filter for i386.
- All high-level filter additions are now moved from execute.c to
seccomp-util.c, so that we can test them independently of the service
execution logic.
- Tests have been added for all types of our seccomp filters.
- SystemCallFilters= and SystemCallArchitectures= are now implemented in
independent filters and installation logic, as they semantically are
very much independent of each other.
Fixes: #4575
This adds two new settings BindPaths= and BindReadOnlyPaths=. They allow
defining arbitrary bind mounts specific to particular services. This is
particularly useful for services with RootDirectory= set as this permits making
specific bits of the host directory available to chrooted services.
The two new settings follow the concepts nspawn already possess in --bind= and
--bind-ro=, as well as the .nspawn settings Bind= and BindReadOnly= (and these
latter options should probably be renamed to BindPaths= and BindReadOnlyPaths=
too).
Fixes: #3439
Let's store the invocation ID in the per-service keyring as a root-owned key,
with strict access rights. This has the advantage over the environment-based ID
passing that it also works from SUID binaries (as they key cannot be overidden
by unprivileged code starting them), in contrast to the secure_getenv() based
mode.
The invocation ID is now passed in three different ways to a service:
- As environment variable $INVOCATION_ID. This is easy to use, but may be
overriden by unprivileged code (which might be a bad or a good thing), which
means it's incompatible with SUID code (see above).
- As extended attribute on the service cgroup. This cannot be overriden by
unprivileged code, and may be queried safely from "outside" of a service.
However, it is incompatible with containers right now, as unprivileged
containers generally cannot set xattrs on cgroupfs.
- As "invocation_id" key in the kernel keyring. This has the benefit that the
key cannot be changed by unprivileged service code, and thus is safe to
access from SUID code (see above). But do note that service code can replace
the session keyring with a fresh one that lacks the key. However in that case
the key will not be owned by root, which is easily detectable. The keyring is
also incompatible with containers right now, as it is not properly namespace
aware (but this is being worked on), and thus most container managers mask
the keyring-related system calls.
Ideally we'd only have one way to pass the invocation ID, but the different
ways all have limitations. The invocation ID hookup in journald is currently
only available on the host but not in containers, due to the mentioned
limitations.
How to verify the new invocation ID in the keyring:
# systemd-run -t /bin/sh
Running as unit: run-rd917366c04f847b480d486017f7239d6.service
Press ^] three times within 1s to disconnect TTY.
# keyctl show
Session Keyring
680208392 --alswrv 0 0 keyring: _ses
250926536 ----s-rv 0 0 \_ user: invocation_id
# keyctl request user invocation_id
250926536
# keyctl read 250926536
16 bytes of data in key:
9c96317c ac64495a a42b9cd7 4f3ff96b
# echo $INVOCATION_ID
9c96317cac64495aa42b9cd74f3ff96b
# ^D
This creates a new transient service runnint a shell. Then verifies the
contents of the keyring, requests the invocation ID key, and reads its payload.
For comparison the invocation ID as passed via the environment variable is also
displayed.
This patch ensures that each system service gets its own session kernel keyring
automatically, and implicitly. Without this a keyring is allocated for it
on-demand, but is then linked with the user's kernel keyring, which is OK
behaviour for logged in users, but not so much for system services.
With this change each service gets a session keyring that is specific to the
service and ceases to exist when the service is shut down. The session keyring
is not linked up with the user keyring and keys hence only search within the
session boundaries by default.
(This is useful in a later commit to store per-service material in the keyring,
for example the invocation ID)
(With input from David Howells)
For some reasons units remaining in the same process group as PID 1
(same_pgrp=true) fail to acquire the console even if it's not taken by anyone.
So always accept for units with same_pgrp set for now.
