On Wed, Mar 24, 2021 at 12:21 PM Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> wrote: > > On 2021/03/24 20:10, Mimi Zohar wrote: > > On Wed, 2021-03-24 at 19:10 +0900, Tetsuo Handa wrote: > >> On 2021/03/24 1:13, Mimi Zohar wrote: > >>> On Wed, 2021-03-24 at 00:14 +0900, Tetsuo Handa wrote: > >>>> On 2021/03/23 23:47, Mimi Zohar wrote: > >>>>> Initially I also questioned making "integrity" an LSM. Perhaps it's > >>>>> time to reconsider. For now, it makes sense to just fix the NULL > >>>>> pointer dereferencing. > >>>> > >>>> Do we think calling panic() as "fix the NULL pointer dereferencing" ? > >>> > >>> Not supplying "integrity" as an "lsm=" option is a user error. There > >>> are only two options - allow or deny the caller to proceed. If the > >>> user is expecting the integrity subsystem to be properly working, > >>> returning a NULL and allowing the system to boot (RFC patch version) > >>> does not make sense. Better to fail early. > >> > >> What does the "user" mean? Those who load the vmlinux? > >> Only the "root" user (so called administrators)? > >> Any users including other than "root" user? > >> > >> If the user means those who load the vmlinux, that user is explicitly asking > >> for disabling "integrity" for some reason. In that case, it is a bug if > >> booting with "integrity" disabled is impossible. > >> > >> If the user means something other than those who load the vmlinux, > >> is there a possibility that that user (especially non "root" users) is > >> allowed to try to use "integrity" ? If processes other than global init > >> process can try to use "integrity", wouldn't it be a DoS attack vector? > >> Please explain in the descripotion why calling panic() does not cause > >> DoS attack vector. > > > > User in this case, is anyone rebooting the system and is intentionally > > changing the default values, dropping the "integrity" option on the > > boot command line. > > OK. Then, I expect that the system boots instead of calling panic(). > That user is explicitly asking for disabling "integrity" for some reason. That was actually my intention. The prebuilt kernel that I use for things has all LSMs enabled, but then I needed to try some workload with only 1 specific LSM, so I gave a different lsm= argument.
