Commit ff27f38e authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Kees Cook

seccomp: Document two-phase seccomp and arch-provided seccomp_data

The description of how archs should implement seccomp filters was
still strictly correct, but it failed to describe the newly
available optimizations.
Signed-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent d39bd00d
......@@ -323,6 +323,17 @@ config HAVE_ARCH_SECCOMP_FILTER
results in the system call being skipped immediately.
- seccomp syscall wired up
For best performance, an arch should use seccomp_phase1 and
seccomp_phase2 directly. It should call seccomp_phase1 for all
syscalls if TIF_SECCOMP is set, but seccomp_phase1 does not
need to be called from a ptrace-safe context. It must then
call seccomp_phase2 if seccomp_phase1 returns anything other
than SECCOMP_PHASE1_OK or SECCOMP_PHASE1_SKIP.
As an additional optimization, an arch may provide seccomp_data
directly to seccomp_phase1; this avoids multiple calls
to the syscall_xyz helpers for every syscall.
config SECCOMP_FILTER
def_bool y
depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
......
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