> On Feb 26, 2018, at 4:49 PM, Kees Cook <[email protected]> wrote: > >> On Wed, Feb 14, 2018 at 9:19 AM, Andy Lutomirski <[email protected]> wrote: >>> On Wed, Feb 14, 2018 at 3:29 PM, Tycho Andersen <[email protected]> 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 <[email protected]> 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... >
BPF_CALL. Alexei, can we make it so that each bpf program type can easily limit which BPF_CALL helpers can be use and allow bpf program types to add their own helpers?c
