On Sun, Feb 21, 2021 at 8:11 PM Mickaël Salaün <mic@xxxxxxxxxxx> wrote: > > > On 21/02/2021 09:50, Masahiro Yamada wrote: > > On Tue, Feb 16, 2021 at 4:03 AM Ondrej Mosnacek <omosnace@xxxxxxxxxx> wrote: > >> > >> On Mon, Feb 15, 2021 at 7:17 PM Mickaël Salaün <mic@xxxxxxxxxxx> wrote: > >>> From: Mickaël Salaün <mic@xxxxxxxxxxxxxxxxxxx> > >>> > >>> Thanks to the previous commit, this gives the opportunity to users, when > >>> running make oldconfig, to update the list of enabled LSMs at boot time > >>> if an LSM has just been enabled or disabled in the build. Moreover, > >>> this list only makes sense if at least one LSM is enabled. > >>> > >>> Cc: Casey Schaufler <casey@xxxxxxxxxxxxxxxx> > >>> Cc: James Morris <jmorris@xxxxxxxxx> > >>> Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx> > >>> Cc: Serge E. Hallyn <serge@xxxxxxxxxx> > >>> Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxxxxxxxxxx> > >>> Link: https://lore.kernel.org/r/20210215181511.2840674-4-mic@xxxxxxxxxxx > >>> --- > >>> > >>> Changes since v1: > >>> * Add CONFIG_SECURITY as a dependency of CONFIG_LSM. This prevent an > >>> error when building without any LSMs. > >>> --- > >>> security/Kconfig | 4 ++++ > >>> 1 file changed, 4 insertions(+) > >>> > >>> diff --git a/security/Kconfig b/security/Kconfig > >>> index 7561f6f99f1d..addcc1c04701 100644 > >>> --- a/security/Kconfig > >>> +++ b/security/Kconfig > >>> @@ -277,6 +277,10 @@ endchoice > >>> > >>> config LSM > >>> string "Ordered list of enabled LSMs" > >>> + depends on SECURITY || SECURITY_LOCKDOWN_LSM || SECURITY_YAMA || \ > >>> + SECURITY_LOADPIN || SECURITY_SAFESETID || INTEGRITY || \ > >>> + SECURITY_SELINUX || SECURITY_SMACK || SECURITY_TOMOYO || \ > >>> + SECURITY_APPARMOR || BPF_LSM > >> > >> This looks really awkward, since all of these already depend on > >> SECURITY (if not, it's a bug)... I guarantee you that after some time > >> someone will come, see that the weird boolean expression is equivalent > >> to just SECURITY, and simplify it. > > > > > > Currently, LSM does not depend on SECURITY. > > So you can always define LSM irrespective of SECURITY, > > which seems a bug. > > > > So, I agree with adding 'depends on SECURITY'. > > > > What he is trying to achieve in this series > > seems wrong, of course. > > This may be wrong in the general case, but not for CONFIG_LSM. > > > > > > >> I assume the new mechanism wouldn't work as intended if there is just > >> SECURITY? If not, then maybe you should rather specify this value > >> dependency via some new field rather than abusing "depends on" (say, > >> "value depends on"?). The fact that a seemingly innocent change to the > >> config definition breaks your mechanism suggests that the design is > >> flawed. > > Masahiro, what do you think about this suggested "value depends on"? Of course, no. See the help text in init/Kconfig: This choice is there only for converting CONFIG_DEFAULT_SECURITY in old kernel configs to CONFIG_LSM in new kernel configs. Don't change this choice unless you are creating a fresh kernel config, for this choice will be ignored after CONFIG_LSM has been set. When CONFIG_LSM is already set in the .config, this choice is just ignored. So, oldconfig is working as the help message says. If you think 2623c4fbe2ad1341ff2d1e12410d0afdae2490ca is a pointless commit, you should ask Kees about it. > >> > >> I do think this would be a useful feature, but IMHO shouldn't be > >> implemented like this. > >> > >>> default "lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK > >>> default "lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR > >>> default "lockdown,yama,loadpin,safesetid,integrity,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO > >>> -- > >>> 2.30.0 > >>> > >> > >> -- > >> Ondrej Mosnacek > >> Software Engineer, Linux Security - SELinux kernel > >> Red Hat, Inc. > >> > > > > -- Best Regards Masahiro Yamada