On Thu, Mar 26, 2020 at 7:29 AM KP Singh <kpsingh@xxxxxxxxxxxx> 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> > Reviewed-by: Brendan Jackman <jackmanb@xxxxxxxxxx> > Reviewed-by: Florent Revest <revest@xxxxxxxxxx> > --- Acked-by: Andrii Nakryiko <andriin@xxxxxx> > include/linux/bpf_lsm.h | 11 ++++++++ > kernel/bpf/bpf_lsm.c | 28 ++++++++++++++++++++ > kernel/bpf/btf.c | 9 ++++++- > kernel/bpf/syscall.c | 57 ++++++++++++++++++++++++++++------------- > kernel/bpf/trampoline.c | 17 +++++++++--- > kernel/bpf/verifier.c | 19 +++++++++++--- > 6 files changed, 114 insertions(+), 27 deletions(-) > [...] > @@ -2479,6 +2496,10 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr) > } > buf[sizeof(buf) - 1] = 0; > tp_name = buf; > + break; > + default: > + err = -EINVAL; > + goto out_put_prog; > } is indentation off here or it's my email client? [...]
