GHSA-w6fv-6gcc-x825

### Impact Zincati ships a polkit rule which allows the `zincati` system user to use the following actions: - `org.projectatomic.rpmostree1.deploy`: used to deploy updates to the system - `org.projectatomic.rpmostree1.finalize-deployment`: used to reboot the system into the deployed update Since Zincati [v0.0.24](https://github.com/coreos/zincati/releases/tag/v0.0.24), this polkit rule contains a logic error which broadens access of those polkit actions to any unprivileged user rather than just the `zincati` system user. In practice, this means that any unprivileged user with access to the system D-Bus socket is able to deploy older Fedora CoreOS versions (which may have other known vulnerabilities). Note that rpm-ostree enforces that the selected version must be from the same branch the system is currently on so this cannot directly be used to deploy an attacker-controlled update payload. This primarily impacts users running untrusted workloads with access to the system D-Bus socket. Note that in general, untrusted workloads should not be given this access, whether containerized or not. By default, containers do not have access to the system D-Bus socket. ### Patches The logic error is fixed in Zincati v0.0.30. The fix is included in the following FCOS releases: - On the `stable` stream: 41.20250302.3.2 - On the `testing` stream: 41.20250315.2.0 - On the `next` stream: 42.20250316.1.0 ### Workarounds A workaround is to add the following polkit rule: ```javascript polkit.addRule(function(action, subject) { if (action.id == "org.projectatomic.rpmostree1.deploy" || action.id == "org.projectatomic.rpmostree1.finalize-deployment" || action.id == "org.projectatomic.rpmostree1.cleanup") { if (subject.user != "zincati") { return polkit.Result.NO; } } }); ``` to e.g. `/etc/polkit-1/rules.d/00-zincati-fix.rules` (it must sort earlier than `zincati.rules` lexicographically). Note that this rule will deny all non-root users other than `zincati` from using those actions. If you've added polkit rules to allow e.g. the `core` user or other users, you will need to adjust the policy (or make sure the ordering is appropriate). ### References This issue was introduced by [this commit](https://github.com/coreos/zincati/commit/28a43aa2c1edda091ba659677d73c13e6e3ea99d), and is fixed in [v0.0.30](https://github.com/coreos/zincati/releases/tag/v0.0.30).