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authorAndy Lutomirski <luto@amacapital.net>2014-07-21 18:49:17 -0700
committerKees Cook <keescook@chromium.org>2014-09-03 14:58:17 -0700
commitff27f38e0ef978aee4c9f7e3a4f3403aae832de2 (patch)
tree34fa7b7f8c1b74a29eed8f59de8d00c396433e14 /arch/Kconfig
parentd39bd00deabe57420f2a3669eb71b0e0c4997184 (diff)
downloadkernel-ff27f38e0ef978aee4c9f7e3a4f3403aae832de2.tar.gz
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: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'arch/Kconfig')
-rw-r--r--arch/Kconfig11
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index 0eae9df35b88..05d7a8a458d5 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -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