On Wed, Aug 17, 2022 at 5:24 PM Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote: > I object to adding the new system configuration knob. > > Especially when I don't see people explaining why such a knob is a good > idea. What is userspace going to do with this new feature that makes it > worth maintaining in the kernel? >From https://lore.kernel.org/all/CAEiveUdPhEPAk7Y0ZXjPsD=Vb5hn453CHzS9aG-tkyRa8bf_eg@xxxxxxxxxxxxxx/ "We have valid use cases not specifically related to the attack surface, but go into the middle from bpf observability to enforcement. As we want to track namespace creation, changes, nesting and per task creds context depending on the nature of the workload." -Djalal Harouni >From https://lore.kernel.org/linux-security-module/CALrw=nGT0kcHh4wyBwUF-Q8+v8DgnyEJM55vfmABwfU67EQn=g@xxxxxxxxxxxxxx/ "[W]e do want to embrace user namespaces in our code and some of our workloads already depend on it. Hence we didn't agree to Debian's approach of just having a global sysctl. But there is "our code" and there is "third party" code, which might not even be open source due to various reasons. And while the path exists for that code to do something bad - we want to block it." -Ignat Korchagin >From https://lore.kernel.org/linux-security-module/CAHC9VhSKmqn5wxF3BZ67Z+-CV7sZzdnO+JODq48rZJ4WAe8ULA@xxxxxxxxxxxxxx/ "I've heard you talk about bugs being the only reason why people would want to ever block user namespaces, but I think we've all seen use cases now where it goes beyond that. However, even if it didn't, the need to build high confidence/assurance systems where big chunks of functionality can be disabled based on a security policy is a very real use case, and this patchset would help enable that." -Paul Moore (with apologies for self-quoting) >From https://lore.kernel.org/linux-security-module/CAHC9VhRSCXCM51xpOT95G_WVi=UQ44gNV=uvvG23p8wn16uYSA@xxxxxxxxxxxxxx/ "One of the selling points of the BPF LSM is that it allows for various different ways of reporting and logging beyond audit. However, even if it was limited to just audit I believe that provides some useful justification as auditing fork()/clone() isn't quite the same and could be difficult to do at scale in some configurations." -Paul Moore (my apologies again) >From https://lore.kernel.org/linux-security-module/20220722082159.jgvw7jgds3qwfyqk@wittgenstein/ "Nice and straightforward." -Christian Brauner -- paul-moore.com
