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Groups > linux.kernel > #1197904
| From | cee1 <fykcee1@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: Revisit AF_BUS: is it a better way to implement KDBUS? |
| Date | 2015-08-01 04:10 +0200 |
| Message-ID | <pSupj-7vb-1@gated-at.bofh.it> (permalink) |
| References | <pRVKV-7H0-11@gated-at.bofh.it> <pS0AV-6aH-1@gated-at.bofh.it> <pSlm2-2GV-21@gated-at.bofh.it> <pSpSI-UC-71@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
2015-08-01 5:15 GMT+08:00 Andy Lutomirski <luto@amacapital.net>: > On Fri, Jul 31, 2015 at 9:25 AM, cee1 <fykcee1@gmail.com> wrote: >> 2015-07-31 2:12 GMT+08:00 Andy Lutomirski <luto@amacapital.net>: >>> >>> I find myself wondering whether an in-kernel *bus* is a good idea at >>> all. Creating a bus that unprivileged programs are allowed to >>> broadcast on (which is kind of the point) opens up big cans of worms. >> >> This can be solved in this AF_BUS like this: >> * Becoming a bus master needs a proper CAP. >> * Impose a bus endpoint to join multicast address "maddr1" first, if >> it wants to send to multicast address "maddr2". >> >> The bus endpoint sends the request of joining maddr1, and the bus >> master grants it with replying a cmsg(control message) and setting up >> a proper eBPF. >> >> Next time, the bus endpoint sends to maddr2, the kernel will allow this if: >> 1) maddr1 & maddr2 == maddr1 >> And 2) the eBPF allows it. >> (i.e. the same multicast match logic in this AF_BUS) >> > > I don't understand. > > If the endpoint is unprivileged (i.e. random untrusted things can send > multicast), then you have the scaling problem. If the endpoint is > privileged, then it's much less clear to me that this thing is useful. That means an endpoint has to request the ability of sending to a specific multicast address(aka join a multicast group), and it's up to bus master whether grants it or not. -- Regards, - cee1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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Re: Revisit AF_BUS: is it a better way to implement KDBUS? cee1 <fykcee1@gmail.com> - 2015-07-31 18:30 +0200 Re: Revisit AF_BUS: is it a better way to implement KDBUS? cee1 <fykcee1@gmail.com> - 2015-08-01 04:10 +0200
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