This changes the ProtectSystem= documentation to refer in more explicit
words to the restrictions of ReadOnlyPath=, as sugegsted in #9857.
THis also extends the paragraph in ReadOnlyPath= that explains the hole.
Fixes: #9857
Add LogRateLimitIntervalSec= and LogRateLimitBurst= options for
services. If provided, these values get passed to the journald
client context, and those values are used in the rate limiting
function in the journal over the the journald.conf values.
Part of #10230
The behaviour described *was* observed on Fedora 28
(systemd-238-9.git0e0aa59), with and without SELinux. I don't actually
know why though! It contradicts my understanding of the code, including an
explicit comment in the code.
Testing in a VM upgraded to v239-792-g1327f272d, this behaviour goes away.
Test case:
# /etc/systemd/system/mount-test.service
[Service]
MountFlags=shared
Type=oneshot
ExecStart=/usr/bin/ls -l /proc/1/ns/mnt /proc/self/ns/mnt
ExecStart=/usr/bin/grep ext4 /proc/self/mountinfo
Weird old behaviour: new mount namespace but / is fully shared.
lrwxrwxrwx. 1 root root 0 Sep 14 11:18 /proc/1/ns/mnt -> mnt:[4026531840]
lrwxrwxrwx. 1 root root 0 Sep 14 11:48 /proc/self/ns/mnt ->
mnt:[4026532851]
968 967 253:0 / / rw,relatime shared:1 - ext4 /dev/mapper/alan_dell_2016...
Current behaviour: / is not fully shared
lrwxrwxrwx. 1 root root 0 Sep 14 11:39 /proc/1/ns/mnt -> mnt:[4026531840]
lrwxrwxrwx. 1 root root 0 Sep 14 11:41 /proc/self/ns/mnt ->
mnt:[4026532329]
591 558 8:3 / / rw,relatime shared:313 master:1 - ext4 /dev/sda3 rw,secl...
RootImage= may require the following settings
```
DeviceAllow=/dev/loop-control rw
DeviceAllow=block-loop rwm
DeviceAllow=block-blkext rwm
```
This adds the following settings implicitly when RootImage= is
specified.
Fixes#9737.
Currently we employ mostly system call blacklisting for our system
services. Let's add a new system call filter group @system-service that
helps turning this around into a whitelist by default.
The new group is very similar to nspawn's default filter list, but in
some ways more restricted (as sethostname() and suchlike shouldn't be
available to most system services just like that) and in others more
relaxed (for example @keyring is blocked in nspawn since it's not
properly virtualized yet in the kernel, but is fine for regular system
services).
Docbook styles required those to be present, even though the templates that we
use did not show those names anywhere. But something changed semi-recently (I
would suspect docbook templates, but there was only a minor version bump in
recent years, and the changelog does not suggest anything related), and builds
now work without those entries. Let's drop this dead weight.
Tested with F26-F29, debian unstable.
$ perl -i -0pe 's/\s*<authorgroup>.*<.authorgroup>//gms' man/*xml
These lines are generally out-of-date, incomplete and unnecessary. With
SPDX and git repository much more accurate and fine grained information
about licensing and authorship is available, hence let's drop the
per-file copyright notice. Of course, removing copyright lines of others
is problematic, hence this commit only removes my own lines and leaves
all others untouched. It might be nicer if sooner or later those could
go away too, making git the only and accurate source of authorship
information.
This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Since StandardOutput=file:path is more similar to StandardInput= than
StandardInputText=, and only StandardInput= is actually documented above
StandardOutput= whereas StandardInputText= is documented below it, I
assume the intention was to refer to the former.
Previously, reading through systemd.exec(5) one might get the idea that
XDG_SEAT and XDG_VTNR are part of the service management logic, but they
are not, they are only set if pam_systemd is part of a PAM stack an
pam_systemd is used.
Hence, let's drop these env vars from the list of env vars, and instead
add a paragraph after the list mentioning that pam_systemd might add
more systemd-specific env vars if included in the PAM stack for a
service that uses PAMName=.
Double newlines (i.e. one empty lines) are great to structure code. But
let's avoid triple newlines (i.e. two empty lines), quadruple newlines,
quintuple newlines, …, that's just spurious whitespace.
It's an easy way to drop 121 lines of code, and keeps the coding style
of our sources a bit tigther.
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
Before this change all unit types would default to "private" in the
system service manager and "inherit" to in the user service manager.
With this change this is slightly altered: non-service units of the
system service manager are now run with KeyringMode=shared. This appears
to be the more appropriate choice as isolation is not as desirable for
mount tools, which regularly consume key material. After all mounts are
a shared resource themselves as they appear system-wide hence it makes a
lot of sense to share their key material too.
Fixes: #8159
The VDSO provided by the kernel for x32, uses x86-64 syscalls instead of
x32 ones.
I think we can safely allow this; the set of x86-64 syscalls should be
very similar to the x32 ones. The real point is not to allow *x86*
syscalls, because some of those are inconveniently multiplexed and we're
apparently not able to block the specific actions we want to.
> Only system calls of the *specified* architectures will be permitted to
> processes of this unit.
(my emphasis)
> Note that setting this option to a non-empty list implies that
> native is included too.
Attempting to use "implies" in the later sentence, in a way that
contradicts the very clear meaning of the earlier sentence... it's too
much.
The long long list of settings is getting too confusing, let's add some
sections and reorder things in them.
This makes no changes regarding contents, it only reorders things,
sometimes reindents them, and adds sections that made sense to me to
some degree.
Within each sections the settings are ordered by relevance (at least
according to how relevant I personally find them), and not
alphabetically.
Let's clarify that these settings only apply to stdout/stderr logging.
Always mention the journal before syslog (as the latter is in most ways
just a legacy alias these days). Always mention the +console cases too.
MemoryDenyWriteExecution policy could be be bypassed by using pkey_mprotect
instead of mprotect to create an executable writable mapping.
The impact is mitigated by the fact that the man page says "Note that this
feature is fully available on x86-64, and partially on x86", so hopefully
people do not rely on it as a sole security measure.
Found by Karin Hossen and Thomas Imbert from Sogeti ESEC R&D.
https://bugs.launchpad.net/bugs/1725348
This makes each system call in SystemCallFilter= blacklist optionally
takes errno name or number after a colon. The errno takes precedence
over the one given by SystemCallErrorNumber=.
C.f. #7173.
Closes#7169.
This removes the '@credentials' syscall set that was added in commit
v234-468-gcd0ddf6f75.
Most of these syscalls are so simple that we do not want to filter them.
They work on the current calling process, doing only read operations,
they do not have a deep kernel path.
The problem may only be in 'capget' syscall since it can query arbitrary
processes, and used to discover processes, however sending signal 0 to
arbitrary processes can be used to discover if a process exists or not.
It is unfortunate that Linux allows to query processes of different
users. Lets put it now in '@process' syscall set, and later we may add
it to a new '@basic-process' set that allows most basic process
operations.
Usually, it's a good thing that we isolate the kernel session keyring
for the various services and disconnect them from the user keyring.
However, in case of the cryptsetup key caching we actually want that
multiple instances of the cryptsetup service can share the keys in the
root user's user keyring, hence we need to be able to disable this logic
for them.
This adds KeyringMode=inherit|private|shared:
inherit: don't do any keyring magic (this is the default in systemd --user)
private: a private keyring as before (default in systemd --system)
shared: the new setting
If two separate log streams are connected to stdout and stderr, let's
make sure $JOURNAL_STREAM points to the latter, as that's the preferred
log destination, and the environment variable has been created in order
to permit services to automatically upgrade from stderr based logging to
native journal logging.
Also, document this behaviour.
Fixes: #6800
With this setting we can explicitly unset specific variables for
processes of a unit, as last step of assembling the environment block
for them. This is useful to fix#6407.
While we are at it, greatly expand the documentation on how the
environment block for forked off processes is assembled.
"Currently, the following values are defined: xxx: in case <condition>" is
awkward because "xxx" is always defined unconditionally. It is _used_ in case
<condition> is true. Correct this and a bunch of other places where the
sentence structure makes it unclear what is the subject of the sentence.
This reworks the paragraph describing $SERVICE_RESULT into a table, and
adds two missing entries: "success" and "start-limit-hit".
These two entries are then also added to the table explaining the
$EXIT_CODE + $EXIT_STATUS variables.
Fixes: #6597
Add LockPersonality boolean to allow locking down personality(2)
system call so that the execution domain can't be changed.
This may be useful to improve security because odd emulations
may be poorly tested and source of vulnerabilities, while
system services shouldn't need any weird personalities.
This new group lists all UID/GID credential changing syscalls (which are
quite a number these days). This will become particularly useful in a
later commit, which uses this group to optionally permit user credential
changing to daemons in case ambient capabilities are not available.
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.
Also updates the documentation and adds a mention of ppc64 support
which was enabled by #5325.
Tested on Debian mipsel and mips64el. The other 4 mips architectures
should have an identical user <-> kernel ABI to one of the 2 tested
systems.
Let's clarify that RestrictAddressFamilies= and MemoryDenyWriteExecute=
are only fully effective if non-native system call architectures are
disabled, since they otherwise may be used to circumvent the filters, as
the filters aren't equally effective on all ABIs.
Fixes: #5277
