On Fri, 27 Mar 2020, KP Singh wrote: > From: KP Singh <kpsingh@xxxxxxxxxx> > > JITed BPF programs are dynamically attached to the LSM hooks > using BPF trampolines. The trampoline prologue generates code to handle > conversion of the signature of the hook to the appropriate BPF context. > > The allocated trampoline programs are attached to the nop functions > initialized as LSM hooks. > > BPF_PROG_TYPE_LSM programs must have a GPL compatible license and > and need CAP_SYS_ADMIN (required for loading eBPF programs). > > Upon attachment: > > * A BPF fexit trampoline is used for LSM hooks with a void return type. > * A BPF fmod_ret trampoline is used for LSM hooks which return an > int. The attached programs can override the return value of the > bpf LSM hook to indicate a MAC Policy decision. > > Signed-off-by: KP Singh <kpsingh@xxxxxxxxxx> > Acked-by: Andrii Nakryiko <andriin@xxxxxx> > Reviewed-by: Brendan Jackman <jackmanb@xxxxxxxxxx> > Reviewed-by: Florent Revest <revest@xxxxxxxxxx> Acked-by: James Morris <jamorris@xxxxxxxxxxxxxxxxxxx> -- James Morris <jmorris@xxxxxxxxx>
