On 15/06/17 00:51, Julien Gomes wrote: > Hi Nikolay, > > On 06/14/2017 05:04 AM, Nikolay Aleksandrov wrote: > >> This has been on our todo list and I'm definitely interested in the >> implementation. >> A few things that need careful consideration from my POV. First are the >> security >> implications - this sends rtnl multicast messages but the rtnl socket has >> the NL_CFG_F_NONROOT_RECV flag thus allowing any user on the system to >> listen in. >> This would allow them to see the full packets and all reports (granted they >> can see >> the notifications even now), but the full packet is like giving them the >> opportunity >> to tcpdump the PIM traffic. > > I definitely see how this can be an issue. > From what I see, this means that either the packet should be > transmitted another way, or another Netlink family should be used. > > NETLINK_ROUTE looks to be the logical family to choose though, > but then I do not see a proper other way to handle this.
Right, currently me neither, unless it provides a bind callback when registering the kernel socket. > > However I may just not be looking into the right direction, > maybe you currently have another approach in mind? I haven't gotten around to make (or even try) them but I was thinking about 2 options ending up with a similar result: 1) genetlink It also has the NONROOT_RECV flag, but it also allows for a callback - mcast_bind() which can be used to filter. or 2) Providing a bind callback to the NETLINK_ROUTE socket. I haven't checked in detail how feasible each option is. To me 2) seems like the cleaner/proper way to do it but it requires extending the rtnetlink api. It would be nice to get feedback and comments from more people on this. > >> My second (more fixable and minor) concern is about the packet itself, how >> do you >> know that the packet is all linear so you can directly copy it ? > > Indeed, I overlooked this possibility in this version. > I will improve that. > Thanks!
