On Wed, 2018-04-04 at 08:57 -0400, Theodore Y. Ts'o wrote: > On Wed, Apr 04, 2018 at 04:30:18AM +0000, Matthew Garrett wrote: > > What I'm afraid of is this turning into a "security" feature that ends up > > being circumvented in most scenarios where it's currently deployed - eg, > > module signatures are mostly worthless in the non-lockdown case because you > > can just grab the sig_enforce symbol address and then kexec a preamble that > > flips it back to N regardless of the kernel config. > > Whoa. Why doesn't lockdown prevent kexec? Put another away, why > isn't this a problem for people who are fearful that Linux could be > used as part of a Windows boot virus in a Secure UEFI context? > > If lockdown simply included a requirement for a signed kernel for > kexec --- and if kernel signing aren't available, to simply not alow > kexec, wouldn't that take care of this case? > > This wouldn't even be all that much of a burden for non-distro users > with lockdown enabled, since in my experience outside of enterprise > and data center use cases, kexec isn't used... Lots of folks use kdump, ergo kexec. -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
