On Mon, Jun 6, 2016 at 9:03 AM, Kees Cook <keesc...@chromium.org> wrote: > On Fri, Jun 3, 2016 at 10:16 PM, Andy Lutomirski <l...@amacapital.net> wrote: >> https://bugzilla.mozilla.org/show_bug.cgi?id=1176099 >> >> Should SIGSYS be delivered to the handler even if blocked? What, if >> anything, does POSIX say? All I can find is in pthread_sigmask(3p): >> >> If any of the SIGFPE, SIGILL, SIGSEGV, or SIGBUS signals are generated >> while they are blocked, the result is undefined, unless the signal was >> generated by the action of another process, or by one of the functions >> kill(), pthread_kill(), raise(), or sigqueue(). >> >> It would be easy enough to change our behavior so that we deliver the >> signal even if it's blocked or to at least add a flag so that users >> can request that behavior. > > I had trouble following that bug. It sounded like glib just needed a > way to define its signal mask, and that's what they ended up > implementing? > > I think the current behavior is correct. SIGSYS is being generated by > the running process (i.e. the seccomp filter) and if it has a handler > but the signal is blocked, we should treat it as uncaught and kill. On > the other hand, it could be seen like "raise", in which case the > blocking should be ignored? Is there an active problem somewhere here? > It seems like the referenced bug has been fixed already.
Agreed. It could make sense to have a new sigaction flag SA_FORCE: when set, if a non-default handler is installed, the signal is blocked, and the signal is triggered synchronously (forced), then the handler will be called. But that isn't specific to seccomp. --Andy
