On Tue, Oct 03, 2023 at 08:38:34AM +0000, Hengqi Chen wrote: > This patchset introduces two new operations which essentially > splits the SECCOMP_SET_MODE_FILTER process into two steps: > SECCOMP_LOAD_FILTER and SECCOMP_ATTACH_FILTER. > > The SECCOMP_LOAD_FILTER loads the filter and returns a fd > which can be pinned to bpffs. This extends the lifetime of the > filter and thus can be reused by different processes. > With this new operation, we can eliminate a hot path of JITing > BPF program (the filter) where we apply the same seccomp filter > to thousands of micro VMs on a bare metal instance. > > The SECCOMP_ATTACH_FILTER is used to attach a loaded filter. > The filter is represented by a fd which is either returned > from SECCOMP_LOAD_FILTER or obtained from bpffs using bpf syscall. Interesting! I like this idea, thanks for writing it up. Two design notes: - Can you reuse/refactor seccomp_prepare_filter() instead of duplicating the logic into two new functions? - Is there a way to make sure the BPF program coming from the fd is one that was built via SECCOMP_LOAD_FILTER? (I want to make sure we can never confuse a non-seccomp program into getting loaded into seccomp.) -Kees -- Kees Cook
