Let's be more restrictive when validating PID files and MAINPID=
messages: don't accept PIDs that make no sense, and if the configuration
source is not trusted, don't accept out-of-cgroup PIDs. A configuratin
source is considered trusted when the PID file is owned by root, or the
message was received from root.
This should lock things down a bit, in case service authors write out
PID files from unprivileged code or use NotifyAccess=all with
unprivileged code. Note that doing so was always problematic, just now
it's a bit less problematic.
When we open the PID file we'll now use the CHASE_SAFE chase_symlinks()
logic, to ensure that we won't follow an unpriviled-owned symlink to a
privileged-owned file thinking this was a valid privileged PID file,
even though it really isn't.
Fixes: #6632
The new --uid= switch allows selecting the UID from which the
notificaiton messages shall originate.
This is primarily useful for testing purposes, but might have other
uses.
Nowadays people use systemd on many different architectures, so we
shouldn't presuppose that they are using amd64. debootstrap defaults
to the native architecture and this should be good enough.
This adds a simple condition/assert/match to the service manager, to
udev's .link handling and to networkd, for matching the kernel version
string.
In this version we only do fnmatch() based globbing, but we might want
to extend that to version comparisons later on, if we like, by slightly
extending the syntax with ">=", "<=", ">", "<" and "==" expressions.
Follow-up to @poettering’s comments in #7723:
- Slightly expand on the difference between using tmpfiles.d and service
directives
- Mention CacheDirectory=
- Mention LogsDirectory=
- Abbreviate and unify some later descriptions
ConfigDirectory= is not mentioned, since it does not support the
functionality mentioned in the manpage which tmpfiles.d provides:
copying or symlinking default configuration from /usr/share/factory. And
the user package variable file locations don’t mention the directives
because in user units the service can always create the directories
itself (whereas in system units lesser-privileged services lack
permission to create them).
The config example contains wrong specificator for hostname.
It should be %H instead of %h as documented in the man page.
Use correct specificator for hostname.
Old text:
> Note that the User= and
> Group= options are not particularly useful for mount units specifying a
> "Type=" option or using configuration not specified in /etc/fstab;
> mount(8) will refuse options that are not listed in /etc/fstab if it is
> not run as UID 0.
However I recently learnt the following:
> The mount program does not read the /etc/fstab file if both device
> and dir are specified.
Therefore, if both device and dir are specified, the `user` or `users`
options in `fstab` will not have any effect. Run as a normal user,
you will always see
mount: only root can do that
Fix the explanation in the man page.
Also make sure to markup User= and Group= with <varname>.
Up until now, the behaviour in systemd has (mostly) been to silently
ignore failures to action unit directives that refer to an unavailble
controller. The addition of AssertControlGroupController and its
conditional counterpart allow explicit specification of the desired
behaviour when such a situation occurs.
As for how this can happen, it is possible that a particular controller
is not available in the cgroup hierarchy. One possible reason for this
is that, in the running kernel, the controller simply doesn't exist --
for example, the CPU controller in cgroup v2 has only recently been
merged and was out of tree until then. Another possibility is that the
controller exists, but has been forcibly disabled by `cgroup_disable=`
on the kernel command line.
In future this will also support whatever comes out of issue #7624,
`DefaultXAccounting=never`, or similar.
Systemd services are permitted to be scripts, as well as binary
executables.
The same also applies to the underlying /sbin/mount and /sbin/swapon.
It is not necessary for the user to consider what type of program file
these are. Nor is it necessary with systemd-nspawn, to distinguish between
init as a "binary" v.s. a user-specified "program".
Also fix a couple of grammar nits in the modified sentences.
The kernel needs two numbers, but for the user it's most convenient to provide the
user name and have that resolved to uid and gid.
Right now the primary group of the specified user is always used. That's the most
common case anyway. In the future we can extend the --owner option to allow a group
after a colon.
[I added this before realizing that this will not be enough to be used for user
runtime directory. But this seems useful on its own, so I'm keeping this commit.]
Yu Watanabe
John Lin
Shawn Landden
Дилян Палаузов
Lennart Poettering
Zbigniew Jędrzejewski-Szmek
Susant Sahani
Jörg Thalheim
Patrik Flykt
Susant Sahani
nulsoh
Lucas Werkmeister
Dmitry Rozhkov
Alan Jenkins
Chris Down
Ken (Bitsko) MacLeod