On Wed, Feb 14, 2018 at 9:19 AM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: > On Wed, Feb 14, 2018 at 3:29 PM, Tycho Andersen <tycho@xxxxxxxx> wrote: >> On Tue, Feb 13, 2018 at 01:09:20PM -0800, Kees Cook wrote: >>> On Sun, Feb 4, 2018 at 2:49 AM, Tycho Andersen <tycho@xxxxxxxx> wrote: >>> I wonder if this communication should be netlink, which gives a more >>> well-structured way to describe what's on the wire? The reason I ask >>> is because if we ever change the seccomp_data structure, we'll now >>> have two places where we need to deal with it (the first being within >>> the BPF itself). My initial idea was to prefix the communication with >>> a size field, then send the structure, and then I had nightmares, and >>> realized this was basically netlink reinvented. >> >> I suggested netlink in LA, and everyone (especially Andy) groaned very >> loudly :). I'm happy to switch it to netlink if you like, although i >> think memcpy() of structs should be safe here, since the return value >> from read or write can indicate the size of things. > > I could easily get on board with "netlink" (i.e. NLA) messages sent > over an fd. I will object strongly to the use of netlink *sockets*. Yeah, I was thinking NLA over the fd; not a netlink socket. >>> An ERRNO filter would block a USER_NOTIF because it's unconditional. >>> TRACE could be either, USER_NOTIF could be either. >>> >>> This means TRACE rules would be bumped by a USER_NOTIF... hmm. >> >> Yes, I didn't exactly know what to do here. ERRNO, TRAP, and KILL all >> seemed more important than USER_NOTIF, but TRACE didn't. I don't have >> a strong opinion about what to do here, because users can adjust their >> filters accordingly. Let me know what you prefer. > > If we switched to eBPF functions, this whole issue goes away. Yeah, though we'd still need some kind of "wait for answer" eBPF function. It feels wrong to re-use maps for that... -Kees -- Kees Cook Pixel Security _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
