a70581ffb5 added ExecRuntime.ipcns_storage_socket[], and
serialization in exec_runtime_serialize(), and deserialization in exec_runtime_deserialize_one(),
but also deserialization in exec_runtime_deserialize_compat(). exec_runtime_deserialize_compat()
is for deserializating ExecRuntime when it was serialized as part of the unit before
e8a565cb66. There was never any code which would serialize
ExecRuntime.ipcns_storage_socket[] this way, so the deserialization attempts are pointless.
When `NoNewPrivileges=yes`, the service shouldn't have a need for any
setuid/setgid programs, so in case there will be a new mount namespace anyway,
mount the file systems with MS_NOSUID.
We recently started making more use of malloc_usable_size() and rely on
it (see the string_erase() story). Given that we don't really support
sytems where malloc_usable_size() cannot be trusted beyond statistics
anyway, let's go fully in and rework GREEDY_REALLOC() on top of it:
instead of passing around and maintaining the currenly allocated size
everywhere, let's just derive it automatically from
malloc_usable_size().
I am mostly after this for the simplicity this brings. It also brings
minor efficiency improvements I guess, but things become so much nicer
to look at if we can avoid these allocation size variables everywhere.
Note that the malloc_usable_size() man page says relying on it wasn't
"good programming practice", but I think it does this for reasons that
don't apply here: the greedy realloc logic specifically doesn't rely on
the returned extra size, beyond the fact that it is equal or larger than
what was requested.
(This commit was supposed to be a quick patch btw, but apparently we use
the greedy realloc stuff quite a bit across the codebase, so this ends
up touching *a*lot* of code.)
This commit applies the filtering imposed by LogLevelMax on a unit's
processes to messages logged by PID1 about the unit as well.
The target use case for this feature is a service that runs on a timer
many times an hour, where the system administrator decides that writing
a generic success message to the journal every few minutes or seconds
adds no diagnostic value and isn't worth the clutter or disk I/O.
With some versions of the compiler, the _cleanup_ attr makes it think
the variable might be freed/closed when uninitialized, even though it
cannot happen. The added cost is small enough to be worth the benefit,
and optimized builds will help reduce it even further.
Let's be a bit less strict when setting up credentials: if the service
manager didn't receieve a cred, and we shall propagate it down via
LoadCredentials= don't fail. Fail on all other errors though, as before,
and on explicitly listed paths.
The function already has a ridiculous amount of paramaters, let's drop
one that is either not used at all or has a constant value and let's
pick it internally.
Let's make use of the new dissection in all tools where this makes
sense, which are all tools that dissect images, except for those which
inherently operate on state/configuraiton and thus where an image
without state nor configuration is useless (e.g.
systemd-tmpfiles/systemd-firstboot/… --image= switch).
Clean up ignore_signals() + default_signals() + sigaction_many() a bit:
make it unnecessary to explicitly terminate the signal list with -1.
Merge all three calls into a single function that is just called with
slightly different parameters. And eliminate an unnecessary extra
iteration in its inner for() loop.
No change in behaviour.
Implement directives `NoExecPaths=` and `ExecPaths=` to control `MS_NOEXEC`
mount flag for the file system tree. This can be used to implement file system
W^X policies, and for example with allow-listing mode (NoExecPaths=/) a
compromised service would not be able to execute a shell, if that was not
explicitly allowed.
Example:
[Service]
NoExecPaths=/
ExecPaths=/usr/bin/daemon /usr/lib64 /usr/lib
Closes: #17942.
Previously if people enabled RootDirectory=/RootImage= and NotifyAccess=
together, things wouldn't work, they'd have to explicitly add
BindReadOnlyPaths=/run/systemd/notify too.
Let's make this implicit. Since both options are opt-in, if people use
them together it would be pointless not also defining the
BindReadOnlyPaths= entry, in which case we can just do it automatically.
See: #18051
Allow to setup new bind mounts for a service at runtime (via either
DBUS or a new 'systemctl bind' verb) with a new helper that forks into
the unit's mount namespace.
Add a new integration test to cover this.
Useful for zero-downtime addition to services that are running inside
mount namespaces, especially when using RootImage/RootDirectory.
If a service runs with a read-only root, a tmpfs is added on /run
to ensure we can create the airlock directory for incoming mounts
under /run/host/incoming.
This adds the ability to specify truncate:PATH for StandardOutput= and
StandardError=, similar to the existing append:PATH. The code is mostly
copied from the related append: code. Fixes#8983.
This beefs up the READ_FULL_FILE_CONNECT_SOCKET logic of
read_full_file_full() a bit: when used a sender socket name may be
specified. If specified as NULL behaviour is as before: the client
socket name is picked by the kernel. But if specified as non-NULL the
client can pick a socket name to use when connecting. This is useful to
communicate a minimal amount of metainformation from client to server,
outside of the transport payload.
Specifically, these beefs up the service credential logic to pass an
abstract AF_UNIX socket name as client socket name when connecting via
READ_FULL_FILE_CONNECT_SOCKET, that includes the requesting unit name
and the eventual credential name. This allows servers implementing the
trivial credential socket logic to distinguish clients: via a simple
getpeername() it can be determined which unit is requesting a
credential, and which credential specifically.
Example: with this patch in place, in a unit file "waldo.service" a
configuration line like the following:
LoadCredential=foo:/run/quux/creds.sock
will result in a connection to the AF_UNIX socket /run/quux/creds.sock,
originating from an abstract namespace AF_UNIX socket:
@$RANDOM/unit/waldo.service/foo
(The $RANDOM is replaced by some randomized string. This is included in
the socket name order to avoid namespace squatting issues: the abstract
socket namespace is open to unprivileged users after all, and care needs
to be taken not to use guessable names)
The services listening on the /run/quux/creds.sock socket may thus
easily retrieve the name of the unit the credential is requested for
plus the credential name, via a simpler getpeername(), discarding the
random preifx and the /unit/ string.
This logic uses "/" as separator between the fields, since both unit
names and credential names appear in the file system, and thus are
designed to use "/" as outer separators. Given that it's a good safe
choice to use as separators here, too avoid any conflicts.
This is a minimal patch only: the new logic is used only for the unit
file credential logic. For other places where we use
READ_FULL_FILE_CONNECT_SOCKET it is probably a good idea to use this
scheme too, but this should be done carefully in later patches, since
the socket names become API that way, and we should determine the right
amount of info to pass over.
We close fds in two phases, first some and then the some more. When passing
a list of fds to exclude from closing to the closing function, we would
pass some in an array and the rest as separate arguments. For the fds which
should be excluded in both closing phases, let's always create the array
and put the relevant fds there. This has the advantage that if more fds to
exclude in both phases are added later, we don't need to add more positional
arguments.
The list passed to setup_pam() is not changed. I think we could pass more fds
to close there, but I'm leaving that unchanged.
The setting of FD_CLOEXEC on an already open fds is dropped. The fd is opened
in service_allocate_exec_fd() and there is no reason to suspect that it might
have been opened incorrectly. If some rogue code is unsetting our FD_CLOEXEC
bits, then it might flip any fd, no reason to single this one out.
Zbigniew Jędrzejewski-Szmek
Yu Watanabe
Lennart Poettering
Topi Miettinen
Mike Kazantsev
Ryan Hendrickson
Luca Boccassi
Xℹ Ruoyao
Anita Zhang
Susant Sahani
Lucas Werkmeister