If - for whatever reason - a script uses set -u (nounset) and includes
/etc/profile.d/70-systemd-shell-extra.sh (e.g. transitively via
/etc/profile) the script would fail with:
/etc/profile.d/70-systemd-shell-extra.sh: line 15: SHELL_PROMPT_PREFIX: unbound variable
For example:
$ cat > foo.sh <<EOF
#!/bin/sh
set -u
source /etc/profile
EOF
$ chmod 700 foo.sh
$ ./foo.sh
/etc/profile.d/70-systemd-shell-extra.sh: line 15: SHELL_PROMPT_PREFIX: unbound variable
Fix this by using shell parameter substitution[^1] (which is a POSIX
shell concept) to set the $SHELL_* variables to the empty string if
undefined.
[^1]: https://pubs.opengroup.org/onlinepubs/9699919799.2018edition/utilities/V3_chap02.html
Now that we have an explicit userns check we can drop the heuristic for
it, given that it's kinda wrong (because mapping the full host UID range
into a userns is actually a thing people do).
Hence, just delete the code and only keep the userns inode check in
place.
Now that we have a reliable pidns check I don't think we really should
look for cgroupns anymore, it's too weak a check. I mean, if I myself
would implement a desktop app sandbox (like flatpak) I'd always enable
cgroupns, simply to hide the host cgroup hierarchy.
Hence drop the check.
I suggested adding this 4 years ago here:
https://github.com/systemd/systemd/pull/17902#issuecomment-745548306
Document the fact that read-only properties may not have the flag
SD_BUS_VTABLE_UNPRIVILEGED as that is not obvious especially given the
flag is accepted for writable properties.
Based on the check in `add_object_vtable_internal` called by
`sd_bus_add_object_vtable` (as of the current tip of the main branch
f7f5ba0192):
case _SD_BUS_VTABLE_PROPERTY: {
[...]
if ([...] ||
[...]
(v->flags & SD_BUS_VTABLE_UNPRIVILEGED && v->type == _SD_BUS_VTABLE_PROPERTY)) {
r = -EINVAL;
goto fail;
}
(where `_SD_BUS_VTABLE_PROPERTY` means read-only property whereas
`_SD_BUS_VTABLE_WRITABLE_PROPERTY` maps to writable property).
This was implemented in the commit
adacb9575a ("bus: introduce "trusted" bus
concept and encode access control in object vtables") where
`SD_BUS_VTABLE_UNPRIVILEGED` was introduced:
Writable properties are also subject to SD_BUS_VTABLE_UNPRIVILEGED
and SD_BUS_VTABLE_CAPABILITY() for controlling write access to them.
Note however that read access is unrestricted, as PropertiesChanged
messages might send out the values anyway as an unrestricted
broadcast.
/dev/null is a character device, so same_fd() in the fallback path
that compares fstat will fail, as that bails out if the fd refers
to a char device. This happens on kernels without F_DUPFD_QUERY and
without kcmp.
/* test_same_fd */
Assertion 'same_fd(d, e) > 0' failed at src/test/test-fd-util.c:111, function test_same_fd(). Aborting.
Fixes#35552
To reproduce, as an unprivileged user start a docker container and build
and run the unit tests inside it:
$ docker run --rm -ti debian:bookworm bash
...
/* test_close_all_fds */
Successfully forked off '(caf-plain)' as PID 10496.
Skipping PR_SET_MM, as we don't have privileges.
(caf-plain) succeeded.
Failed to fork off '(caf-noproc)': Operation not permitted
Assertion 'r >= 0' failed at src/test/test-fd-util.c:392, function test_close_all_fds(). Aborting.
Partially fixes#35552
have ambient caps: yes
Capabilities:cap_chown,cap_dac_override,cap_fowner,cap_fsetid,cap_kill,cap_setgid,cap_setuid,cap_setpcap,cap_net_bind_service,cap_net_raw,cap_sys_chroot,cap_mknod,cap_audit_write,cap_setfcap=ep
Failed to drop auxiliary groups list: Operation not permitted
Failed to change group ID: Operation not permitted
Capabilities:cap_dac_override,cap_net_raw=ep
Capabilities:cap_dac_override=ep
Successfully forked off '(getambient)' as PID 12505.
Skipping PR_SET_MM, as we don't have privileges.
Ambient capability cap_linux_immutable requested but missing from bounding set, suppressing automatically.
Assertion 'x < 0 || FLAGS_SET(c, UINT64_C(1) << CAP_LINUX_IMMUTABLE)' failed at src/test/test-capability.c:273, function test_capability_get_ambient(). Aborting.
(getambient) terminated by signal ABRT.
src/test/test-capability.c:258: Assertion failed: expected "r" to succeed, but got error: Protocol error
Partially fixes#35552
TEST-75-RESOLVED fails on Ubuntu autopkgtest due to this warning from
knot:
notice: config, policy 'auto_rollover_nsec3' depends on default nsec3-salt-length=8, since version 3.5 the default becomes 0
Explicitly set nsec3-salt-length=8 to silence.
This PR allows an option for systemd exec units to enable UTS namespaces
but not restrict changing hostname via seccomp. Thus, units can change
hostname without affecting the host. This is useful for OS-like
containers running as units where they should have freedom to change
their container hostname if they want, but not the host's hostname.
Fixes: #30348
RestrictNamespaces= would accept "time" but would not actually apply
seccomp filters e.g. systemd-run -p RestrictNamespaces=time unshare -T true
should fail but it succeeded.
This commit actually enables time namespace seccomp filtering.
Previously if one service specified the same unit as their
success and failure handler we bailed out of resolving the triggering unit
even though it is still unique.
Tobias Klauser
Lennart Poettering
Katariina Lounento
Luca Boccassi
Luca Boccassi
Nick Rosbrook
Mike Yuan
Zbigniew Jędrzejewski-Szmek
Yu Watanabe
Daan De Meyer
Samuel Dionne-Riel
Ryan Wilson
Nils K