On April 11, 2018 8:09 PM, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > On Wed, Apr 11, 2018 at 9:24 AM, David Howells dhowells@xxxxxxxxxx wrote: > > > Provide a single call to allow kernel code to determine whether the system > > > > should be locked down, thereby disallowing various accesses that might > > > > allow the running kernel image to be changed, including: > > > > - /dev/mem and similar > > - Loading of unauthorised modules > > - Fiddling with MSR registers > > - Suspend to disk managed by the kernel > > - Use of device DMA > > So what I stlll absolutely detest about this series is that I think > > many of these things should simply be done as separate config options. > > For example, if the distro is sure that it doesn't need /dev/mem, then > > why the hell is this tied to "lockdown" that then may have to be > > disabled because other changes may not be acceptable (eg people may > > need that device DMA, or whatever). > > If that /dev/mem access prevention was just instead done as an even > > stricter mode of the existing CONFIG_STRICT_DEVMEM, it could just be > > enabled unconditionally. CONFIG_DEVMEM=n > > So none of these patches raise my hackles per se. But what continues > > to makes me very very uncomfortable is how this is all tied together. > > Why is this one magical mode that then - because it has such a big > > impact - has to be enabled/disabled as a single magical mode and with > > very odd rules? > > I think a lot of people would be happier if this wasn't so incestuous > > and mixing together independent things under one name, and one flag. > > I think a lot of the secure boot problems were exacerbated by that mixup. > > So I would seriously ask that the distros that have been using these > > patches look at which parts of lockdown they could make unconditional > > (because it doesn't break machines), and which ones need that escape > > clause. > > Linus > Jordan -- 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
