This returns to the original approach proposed in
https://github.com/systemd/systemd/pull/17270. After review, the approach was
changed to use sd_pid_get_owner_uid() instead. Back then, when running in a
typical graphical session, sd_pid_get_owner_uid() would usually return the user
UID, and when running under sudo, geteuid() would return 0, so we'd trigger the
secure path.
sudo may allocate a new session if is invoked outside of a session (depending
on the PAM config). Since nowadays desktop environments usually start the user
shell through user units, the typical shell in a terminal emulator is not part
of a session, and when sudo is invoked, a new session is allocated, and
sd_pid_get_owner_uid() returns 0 too. Technically, the code still works as
documented in the man page, but in the common case, it doesn't do the expected
thing.
$ build/test-sd-login |& rg 'get_(owner_uid|cgroup|session)'
sd_pid_get_session(0) → No data available
sd_pid_get_owner_uid(0) → 1000
sd_pid_get_cgroup(0) → /user.slice/user-1000.slice/user@1000.service/app.slice/app-ghostty-transient-5088.scope/surfaces/556FAF50BA40.scope
$ sudo build/test-sd-login |& rg 'get_(owner_uid|cgroup|session)'
sd_pid_get_session(0) → c289
sd_pid_get_owner_uid(0) → 0
sd_pid_get_cgroup(0) → /user.slice/user-0.slice/session-c289.scope
I think it's worth checking for sudo because it is a common case used by users.
There obviously are other mechanims, so the man page is extended to say that
only some common mechanisms are supported, and to (again) recommend setting
SYSTEMD_LESSSECURE explicitly. The other option would be to set "secure mode"
by default. But this would create an inconvenience for users doing the right
thing, running systemctl and other tools directly, because then they can't run
privileged commands from the pager, e.g. to save the output to a file. (Or the
user would need to explicitly set SYSTEMD_LESSSECURE. One option would be to
set it always in the environment and to rely on sudo and other tools stripping
it from the environment before running privileged code. But that is also fairly
fragile and it obviously relies on the user doing a complicated setup to
support a fairly common use case. I think this decreases usability of the
system quite a bit. I don't think we should build solutions that work in
priniciple, but are painfully inconvenient in common cases.)
Fixes https://yeswehack.com/vulnerability-center/reports/346802.
Also see https://github.com/polkit-org/polkit/pull/562, which adds support for
$SUDO_UID/$SUDO_GID to pkexec.
If zstd frames are corrupted the initial size returned for the current
frame might be wrong. Don#t assert() on that, but handle it gracefully,
as EBADMSG
Let's be strict here: this data is conceptually not NUL terminated,
hence use memory_startswith() rather than startswith() (which implies
NUL termination). All other similar cases in logs-show.c got this right.
Fix the remaining three, too.
With the more efficient sync semantics it's more likely that
journal-upload-journal will try to read a partially written message.
Previously we'd fail then. Let's instead treat this gracefully,
expecting that this is either the end or will be fixed shortly (and
we'll get notified via inotify about it and recheck).
The MHD context owns the fd we watch via our event source, hence when we
destroy the context before the event source the event source might still
reference the fd that is now invalid. Hence swap the order.
The Synchronize() function is just too useful for clients, so that we
can make "systemd-run -v --user" actually useful. Hence let's make the
socket accessible without privs. Deny most method calls however, except
for the Synchronize() call.
Previously, if the Synchronize() varlink call is issued we'd wait for
journald to become idle before returning success. That is problematic
however: on a busy system journald might never become idle. Hence, let's
beef up the logic to ensure that we do not wait longer than necessary:
i.e. we make sure we process any data enqueued before the sync request
was submitted, but not more.
Implementing this isn't trivial unfortunately. To deal with this
reasonably, we need to determine somehow for incoming log messages
whether they are from before or after the point in time where the sync
requested was received.
For AF_UNIX/SOCK_DGRAM we can use SO_TIMESTAMP to directly compare
timestamps of incoming messages with the timestamp of the sync request
(unfortunately only CLOCK_REALTIME).
For AF_UNIX/SOCK_STREAM we can call SIOCINQ at the moment we initiate
the sync, and then continue processing incoming traffic, counting down
the bytes until the SIOCINQ returned bytes have been processed. All
further data must have been enqueued later hence.
With those two mechanisms in place we can relatively reliably
synchronize the journal.
This also adds a boolean argument "offline" to the Synchronize() call,
which controls whether to offline the journal after processing the
pending messages. it defaults to true, for compat with the status quo
ante. But for most cases the offlining is probably not necessary, and is
cheaper to do without, hence allow not to do it.
So far we schduled kmsg events at higher priority than native/syslog
ones. But that's quite problematic, since it means that kmsg events can
drown out native/syslog log events. And this actually shows up in some
CI tests.
Address that, and schedule all three sources at the same priority, so
that the earlier event always is processed first, regarding which
protocol is used.
Let's optionally issue a Varlink Synchronize() call in --follow mode
when asked to terminate. This is useful so that the tool can be called
and it is guaranteed it processed all messages generated before the
request to exit before it exits.
We want this in "systemd-run -v" in particular, so that we can be sure
we are not missing any log output from the invoked service before it
exits
Allow callers to synchronize on the point in time where the journal file
watches are fully established, in --follow mode.
Tools can invoke journalctl using this, knowing that any log message
happening after the READY=1 is definitely going to be processed by the
journalctl invocation.
We soon want to add for sock_diag(7) netlink sockets. Those reuse the
same message type codes for request and response but with different
message formats. Hence we need to look at NLM_F_REQUEST to determine
which message policy to apply. Hence it is essential to know the flags
parameters right away when creating a message, since we cannot do early
validation otherwise.
This only adds support for setting the flags value right at the moment
of creation of the message object, it does not otherwise add
sock_diag(7) support, that is added in a later message.
This also corrects the flag for synthetic NLMSG_ERROR messages which
should not have the NLM_F_REQUEST flag set (since they are responses,
not requests).
Let's extend pid1's varlink interface and add a Describe method to get
the global Manager object information as a JSON object
(io.systemd.Manager.Describe).
Because the new varlink interface should be available on both the user
managers and the system manager, we also make the necessary changes to
expose a varlink server on user managers.
This PR is first part of https://github.com/systemd/systemd/pull/33965
with minimal changes to address feedback.
Fixes: #22654
Add support for a sysfail boot entry. Sysfail boot entries can be used
for optional tweaking the automatic selection order in case a failure
state of the system in some form is detected (boot firmware failure
etc).
The EFI variable `LoaderEntrySysFail` contains the sysfail boot loader
entry to use. It can be set using bootctl:
```
$ bootctl set-sysfail sysfail.conf
```
The `LoaderEntrySysFail` EFI variable would be unset automatically
during next boot by `systemd-boot-clear-sysfail.service` if no system
failure occured, otherwise it would be kept as it is and a system
failure reason will be saved to `LoaderSysFailReason` EFI variable.
`sysfail_check()` expected to be extented to support possibleconditions
when we should boot sysfail("recovery") boot entry.
Also add support for using a sysfail boot entry in case of UEFI firmware
capsule update failure [1]. The status of a firmware update is obtained
from the EFI System Resource Table (ESRT), which provides an optional
mechanism for identifying device and system firmware resources for the
purposes of targeting firmware updates to those resources.
Current implementation uses the value of LastAttemptStatus field from
ESRT, which describes the result of the last firmware update attempt for
the firmware resource entry. The field is updated each time an
`UpdateCapsule()` is attempted for an ESRT entry and is preserved across
reboots (non-volatile).
This can be be used in setups with support for A/B OTA updates, where
the boot firmware and Linux/RootFS might be updated synchronously.
The check is activated by adding "sysfail-firmware-upd" to loader.conf
[1]
https://uefi.org/specs/UEFI/2.10/23_Firmware_Update_and_Reporting.html
Let's extend pid1's varlink interface and add a Describe method to
get the global Manager object information as a JSON object
(io.systemd.Manager.Describe).
Because the new varlink interface should be available on both the
user managers and the system manager, we also make the necessary
changes to expose a varlink server on user managers.
Igor Opaniuk
Mike Yuan
Yu Watanabe
Daan De Meyer
Zbigniew Jędrzejewski-Szmek
Lennart Poettering
Jörg Behrmann
Ryan Thompson
Ivan Kruglov