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 works by 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.
Once this is done, I implemented 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. Now that it's properly
rebased, even the previously expected failures are gone.
Kees, if you like this version, can you create a branch with patches
1-3? I think that the rest should go into tip/x86 once everyone's happy
with it.
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 (7):
seccomp,x86,arm,mips,s390: Remove nr parameter from secure_computing
seccomp: Refactor the filter callback and the API
seccomp: Allow arch code to provide seccomp_data
x86,x32,audit: Fix x32's AUDIT_ARCH wrt audit
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/arm/kernel/ptrace.c | 7 +-
arch/mips/kernel/ptrace.c | 2 +-
arch/s390/kernel/ptrace.c | 2 +-
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 | 146 +++++++++++++++++++-----
arch/x86/kernel/vsyscall_64.c | 2 +-
include/linux/seccomp.h | 25 ++--
kernel/seccomp.c | 252 ++++++++++++++++++++++++++++-------------
10 files changed, 344 insertions(+), 154 deletions(-)
--
1.9.3
