Currently the label database is not reloaded with libselinux 3.2 on a
policy reload.
Since libselinux 3.2 avc_open(3) uses the SELinux status page instead of
a netlink socket to check for policy reloads.
The status page is also queried in mac_selinux_maybe_reload().
Thus calls to selinux_check_access(3) might consume an update, queried
by selinux_status_updated(3), leaving mac_selinux_maybe_reload() unable
to detect a policy reload.
Do not use selinux_status_updated(3), use selinux_status_policyload(3)
unconditionally.
Relevant libselinux commit: https://github.com/SELinuxProject/selinux/commit/05bdc03130d741e53e1fb45a958d0a2c184be503
Debian Bullseye is going to ship libselinux 3.1, so stay compatible for
backports.
Binaries might not initialize SELinux, e.g. when they normally do not
create files with the SELinux default context.
If they, via an internal libary function, call a _label() function,
mac_selinux_maybe_reload() gets called. Since the SELinux status page
has not been opened, selinux_status_updated() will fail with EINVAL.
This affects particularly test binaries.
Just exit early and avoid confusing debug logs.
The parent process may not perform any label operation, so the
database might not get updated on a SELinux policy change on its own.
Reload the label database once on a policy change, instead of n times
in every started child.
Currently systemd-user-runtime-dir does not create the files in
/run/user/$UID/systemd/inaccessible with the default SELinux label.
The user and role part of these labels should be based on the user
related to $UID and not based on the process context of
systemd-user-runtime-dir.
Since v246-rc1 (9664be199a) /run/user/$UID/systemd is also created by
systemd-user-runtime-dir and should also be created with the default
SELinux context.
Since bc8d57f290 mac_selinux_init() is checked and considered fatal
tree-wide.
Coverity complains about it not being checked in the test code.
Follow-up of: #16223
Fixes: CID 1429975
* Drop mac_selinux_use() condition from mac_selinux_free(): if the
passed pointer holds memory we want to free it even if SELinux is
disabled
* Drop NULL-check cause man:freecon(3) states that freecon(NULL) is a
well-defined NOP
* Assert that on non-SELinux builds the passed pointer is always NULL,
to avoid memory leaks
Calling `mac_selinux_enforcing()`, which calls `security_getenforce()`, on a SELinux disabled system causes the following error message to be printed:
Failed to get SELinux enforced status: No such file or directory
Fixes: 257188f80c ("selinux: cache enforced status and treat retrieve failure as enforced mode")
Supersedes: #15145
Reload the internal selabel cache automatically on SELinux policy reloads so non pid-1 daemons are participating.
Run the reload function `mac_selinux_reload()` not manually on daemon-reload, but rather pass it as callback to libselinux.
Trigger the callback prior usage of the systemd internal selabel cache by depleting the selinux netlink socket via `avc_netlink_check_nb()`.
Improves: a9dfac21ec ("core: reload SELinux label cache on daemon-reload")
Improves: #13363
Let systemd create the dummy file where a device node will be mounted on with the default label for the parent directory (e.g. /tmp/namespace-dev-yTMwAe/dev/).
Fixes: #13762
Relevant when testing in permissive mode, where the function does not return a failure to the client.
This helps to configure a system in permissive mode, without getting surprising failures when switching to enforced mode.
`log_enforcing()` and `log_enforcing_errno()` are only used for important messages, which describe failures in enforced mode.
They are guarded either by `!mac_selinux_use()` or `!label_hnd` checks, where the latter is itself guarded by the former.
Only SELinux enabled systems print these logs.
This helps to configure a system in permissive mode, without getting surprising failures when switching to enforced mode.
Reloading the SELinux label cache here enables a light-wight follow-up of a SELinux policy change, e.g. adding a label for a RuntimeDirectory.
Closes: #13363
Christian Göttsche