Hey all!

I know Qubes [assumes trust on the Fedora 
maintainers](https://doc.qubes-os.org/en/latest/developer/system/security-critical-code.html#buggy-code-vs-backdoored-code),
 but I'm wondering if there is value in keeping Fedora repositories and its 
signing key enabled in dom0 after the respective version's EOL, especially by 
default.

As I understand it, the TCB code installed in dom0 is kept up to date via 
Qubes-controlled repositories. From what I've seen, by the time Qubes 4.2 (and 
likely also 4.3) comes out, its Fedora version is already EOL. The only 
use-case I see for wanting this repo after install is to be able to add 
additional dom0 packages (which is generally discouraged).

Qubes' trust on the Fedora maintainers is not being put into question. The 
problem I'd like to highlight is that key holders may not have the same level 
of care about assumed-EOL singing keys: there could be a perceived risk 
difference between EOL keys and current keys. This could be as simple as not 
considering it necessary to do a key compromize disclosure for EOL keys (should 
it ever happen), under the assumption that nobody would be affected, where in 
fact, for Qubes users even more affected than for active fedora release keys.

To summarize, I see the risks as (1) having dom0 compromized due to a 
mismanaged EOL key and the benefits: (2) installing extra dom0 packages and (3) 
building the Qubes ISO using fedora repo's directly (which I have not checked 
if it's actually needed). Unless I'm missing a use-case for dom0's Fedora 
repos, I think this is a risk worth mitigating.

Here are some mutually-exclusive proposed solutions:

- Disable Fedora repo in dom0 for 4.3 and its key by default— advanced users 
who want to install additional dom0 software would be able to, by enabling the 
repo and importing its (already-present) key. This would still expose risks 
during the ISO building process (assuming packages are installed from fedora 
and not built from source).
- Mirror dom0 Fedora repository, but re-sign all artifacts with a Qubes key —  
Under the assumption that Qubes releases always ship an EOL Fedora this would 
be a once-per minor release operation: essentially a trusted snapshot of every 
package's state.

Would this be something that makes sense for Qubes?

Cheers,
deeplow

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