On Tue, Mar 4, 2025 at 9:20 PM Mimi Zohar <zohar@xxxxxxxxxxxxx> wrote: > On Tue, 2025-03-04 at 21:09 -0500, Paul Moore wrote: > > On Tue, Mar 4, 2025 at 8:50 PM Mimi Zohar <zohar@xxxxxxxxxxxxx> wrote: > > > On Tue, 2025-03-04 at 19:19 -0500, Paul Moore wrote: > > > > On Tue, Mar 4, 2025 at 7:54 AM Mimi Zohar <zohar@xxxxxxxxxxxxx> wrote: > > > > > On Mon, 2025-03-03 at 17:38 -0500, Paul Moore wrote: > > > > > > On Fri, Feb 28, 2025 at 12:19 PM Mimi Zohar <zohar@xxxxxxxxxxxxx> wrote: > > > > > > > On Fri, 2025-02-28 at 11:14 -0500, Paul Moore wrote: > > > > > > > > On Fri, Feb 28, 2025 at 9:09 AM Mimi Zohar <zohar@xxxxxxxxxxxxx> wrote: > > > > > > > > > On Thu, 2025-02-27 at 17:22 -0500, Paul Moore wrote: > > > > > > > > > > > > ... > > > > > > > > > > > > > Ok, let's go through different scenarios to see if it would scale. > > > > > > > > > > > > > > Scenario 1: Mostly distro signed userspace applications, minimum number of > > > > > > > developer, customer, 3rd party applications. > > > > > > > > > > > > > > Scenario 2: Multiple developer, customer, 3rd party applications, signed by the > > > > > > > same party. > > > > > > > > > > > > > > Scenario 3: extreme case - every application signed by different party. > > > > > > > > > > > > > > With the minimum case, there would probably be a default key or sets of > > > > > > > permissible keys. In the extreme case, the number of keyrings would be > > > > > > > equivalent to the number of application/software packages. > > > > > > > > > > > > Perhaps we're not understanding each other, but my understanding of > > > > > > the above three scenarios is that they are all examples of signed > > > > > > applications where something (likely something in the kernel like IMA) > > > > > > verifies the signature on the application. While there are going to > > > > > > be differing numbers of keys in each of the three scenarios, I believe > > > > > > they would all be on/linked-to the same usage oriented keyring as they > > > > > > all share the same usage: application signatures. > > > > > > > > > > Yes they're all verifying file signatures, but the software packages are from > > > > > different sources (e.g. distro, chrome), signed by different keys. > > > > > > > > Yep. > > > > > > > > > Only a > > > > > particular key should be used to verify the file signatures for a particular > > > > > application. > > > > > > > > That's definitely one access control policy, but I can also envision a > > > > scenario where I have just one keyring for application signatures with > > > > multiple keys from multiple vendors. > > > > > > Having a single keyring with keys from multiple software vendors is the status > > > quo. > > > > A single keyring with keys from multiple vendors does happen today > > yes, but there is no separation based on how those keys are used, e.g. > > separate application signature and kernel module signature keyrings. > > As soon as you add multiple vendors keys on the kernel module signature keyring, > you'll need finer grained access control. Maybe. It depends on your security policy, some solutions might be okay with keyring level access control granularity, others may want finer grained control. -- paul-moore.com
