On Thu, Sep 6, 2018 at 5:29 PM Tycho Andersen <tycho@xxxxxxxx> wrote: > The idea here is that the userspace handler should be able to pass an fd > back to the trapped task, for example so it can be returned from socket(). [...] > diff --git a/Documentation/userspace-api/seccomp_filter.rst b/Documentation/userspace-api/seccomp_filter.rst > index d1498885c1c7..1c0aab306426 100644 > --- a/Documentation/userspace-api/seccomp_filter.rst > +++ b/Documentation/userspace-api/seccomp_filter.rst > @@ -235,6 +235,9 @@ The interface for a seccomp notification fd consists of two structures: > __u64 id; > __s32 error; > __s64 val; > + __u8 return_fd; > + __u32 fd; > + __u32 fd_flags; Normally, syscalls that take an optional file descriptor accept a signed 32-bit number, with -1 standing for "no file descriptor". Is there a reason why this uses a separate variable to signal whether an fd was provided? Apart from that, this patch looks good to me.
