Re: [PATCH v3] killswitch: add per-function short-circuit mitigation primitive
Sasha Levin <[email protected]>
| Newsgroups | org.kernel.vger.live-patching,org.kernel.vger.bpf,org.kernel.vger.linux-doc,org.kernel.vger.linux-kernel,org.kernel.vger.linux-kselftest |
|---|---|
| Message-ID | <ag8Y8L2WCcSEDPkG@laps> |
On Tue, May 19, 2026 at 03:00:15PM -0700, Song Liu wrote: >On Tue, May 19, 2026 at 12:57 PM Sasha Levin <[email protected]> wrote: >[...] >> >Fully agree with Song here that there is no clear boundary, and that the >> >killswitch could lead to arbitrary, hard to debug breakage if applied to >> >the wrong function.. introducing worse bugs than the one being mitigated >> >or even /short-circuit LSM enforcement/ (engage security_file_open 0, >> >engage cap_capable 0, engage apparmor_* etc). >> >> This is similar to livepatch, right? Do we need guardrails there too? > >livepatch has the same guardrails as other kernel modules: >CONFIG_MODULE_SIG, CONFIG_MODULE_SIG_FORCE, etc. Which the user can choose to enable or disable. Livepatches will work just fine with CONFIG_MODULE_SIG=n, right? With the whitelist approach, the user has no choice but to accept it. Would it make sense to allow disabling the whitelist via a kernel config or some runtime flag? -- Thanks, Sasha