On Tue, Apr 26, 2022 at 02:31:09PM -0700, Matthias Kaehlcke wrote: > I'm still doubting what would be the best way to configure > the list of trusted digests. The approach in v2 of writing > a path through sysctl is flexible, but it also feels a bit > odd. I did some experiments with passing a file descriptor > through sysctl, but it's also odd and has its own issues. > Passing the list through a kernel parameter seems hacky. > A Kconfig string would work, but can be have issues when > the same config is used for different platforms, where > some may have trusted digests and others not. I prefer the idea of passing an fd, since that can just use LoadPin itself to verify the origin of the fd. I also agree, though, that it's weird as a sysctl. Possible thoughts: - make it a new ioctl on /dev/mapper/control (seems reasonable given that it's specifically about dm devices). - have LoadPin grow a securityfs node, maybe something like /sys/kernel/security/loadpin/dm-verify and do the ioctl there (seems reasonable given that it's specifically about LoadPin, but is perhaps more overhead to built the securityfs). -- Kees Cook
