Messages in this thread | | | Date | Wed, 16 Jul 2014 14:57:20 -0700 | Subject | Re: [PATCH 5/7] x86: Split syscall_trace_enter into two phases | From | Kees Cook <> |
| |
On Wed, Jul 16, 2014 at 2:15 PM, Andy Lutomirski <luto@amacapital.net> wrote: > On Wed, Jul 16, 2014 at 1:21 PM, Kees Cook <keescook@chromium.org> wrote: >> On Tue, Jul 15, 2014 at 12:32 PM, Andy Lutomirski <luto@amacapital.net> wrote: >>> >>> + >>> + ret = seccomp_phase1(&sd); >>> + if (ret == SECCOMP_PHASE1_SKIP) { >>> + regs->orig_ax = -ENOSYS; >> >> Before, seccomp didn't touch orig_ax on a skip. I don't see any >> problem with this, and it's probably more clear this way, but are you >> sure there aren't unexpected side-effects from this? > > It's necessary to cause the syscall to be skipped -- see syscall_trace_enter. > > That being said, setting it to -ENOSYS is nonsense and probably > confused you at least as much as it confused me. It should be > regs->orig_ax = -1.
Yes, I think that would be better.
-Kees
-- Kees Cook Chrome OS Security
| |