On Fri, Sep 5, 2014 at 3:13 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: > This applies to: > git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git seccomp-fastpath > > Gitweb: > https://git.kernel.org/cgit/linux/kernel/git/kees/linux.git/log/?h=seccomp/fastpath > > This is both a cleanup and a speedup. It reduces overhead due to > installing a trivial seccomp filter by 87%. The speedup comes from > avoiding the full syscall tracing mechanism for filters that don't > return SECCOMP_RET_TRACE. > > This series depends on splitting the seccomp hooks into two phases. > The first phase evaluates the filter; it can skip syscalls, allow > them, kill the calling task, or pass a u32 to the second phase. The > second phase requires a full tracing context, and it sends ptrace > events if necessary. The seccomp core part is in Kees' seccomp/fastpath > tree. > > These patches implement a similar split for the x86 syscall > entry work. The C callback is invoked in two phases: the first has > only a partial frame, and it can request phase 2 processing with a > full frame. > > Finally, I switch the 64-bit system_call code to use the new split > entry work. This is a net deletion of assembly code: it replaces > all of the audit entry muck. > > In the process, I fixed some bugs. > > If this is acceptable, someone can do the same tweak for the > ia32entry and entry_32 code. > > This passes all seccomp tests that I know of. > > Changes from v4: > - Rebased (which seems to have been a no-op) > - Fixed embarrassing bug that broke allnoconfig > (patch 3 was missing an ifdef). > > Changes from v3: > - Dropped the core seccomp changes from the email -- Kees has applied them. > - Add patch 2 (the TIF_NOHZ change). > - Fix TIF_NOHZ in the two-phase entry code (thanks, Oleg). > > Changes from v2: > - Fixed 32-bit x86 build (and the tests pass). > - Put the doc patch where it belongs. > > Changes from v1: > - Rebased on top of Kees' shiny new seccomp tree (no effect on the x86 > part). > - Improved patch 6 vs patch 7 split (thanks Alexei!) > - Fixed bogus -ENOSYS in patch 5 (thanks Kees!) > - Improved changelog message in patch 6. > > Changes from RFC version: > - The first three patches are more or less the same > - The rest is more or less a rewrite > > Andy Lutomirski (5): > x86,x32,audit: Fix x32's AUDIT_ARCH wrt audit > x86,entry: Only call user_exit if TIF_NOHZ > x86: Split syscall_trace_enter into two phases > x86_64,entry: Treat regs->ax the same in fastpath and slowpath > syscalls > x86_64,entry: Use split-phase syscall_trace_enter for 64-bit syscalls > > arch/x86/include/asm/calling.h | 6 +- > arch/x86/include/asm/ptrace.h | 5 ++ > arch/x86/kernel/entry_64.S | 51 +++++-------- > arch/x86/kernel/ptrace.c | 165 +++++++++++++++++++++++++++++++++-------- > 4 files changed, 164 insertions(+), 63 deletions(-) Consider the series: Acked-by: Kees Cook <keescook@xxxxxxxxxxxx> As far as doing pulls, Peter, can you take the seccomp change from my tree as well? It makes sense to land all of this together. Thanks! -Kees -- Kees Cook Chrome OS Security
