Messages in this thread | | | From | Andy Lutomirski <> | Date | Wed, 16 Jul 2014 14:15:44 -0700 | Subject | Re: [PATCH 5/7] x86: Split syscall_trace_enter into two phases |
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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.
--Andy
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