lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Tue, 4 Feb 2014 23:08:09 +0100 From: "Steinar H. Gunderson" <sgunderson@...foot.com> To: netdev@...r.kernel.org Subject: Re: IGMP joins come from the wrong SA/interface On Thu, Jan 30, 2014 at 11:44:11PM +0100, Hannes Frederic Sowa wrote: > The routing lookup is done at IP_ADD_MEMBERSHIP time. I really wonder why you > have routed the 239.0.0.0/8 range to eth0.11. It seems to me that the kernel > does what you told it to do. ;) > > multicast flag on ip route is just used for multicast forwarding and does not > matter for local multicast. Also if we find unicast route first (more > specific) kernel does not do backtracking if destination is in multicast > scope. Hah, you're right. The issue was a combination of: 1. mediatomb's initscript on Debian at some point started to add a bogus 239.0.0.0/8 route (and I didn't notice this because I earlier tested with addresses outside this range). 2. I didn't properly understand that the multicast flag on the route did not matter (although it really should!). 3. rp_filter ate the data packets when they actually arrived. (I don't know why I never had this problem before, but I certainly didn't.) So in various debugging rounds, I managed to fix #1 and #2 to various degrees, but then #3 would come and make it appear like nothing actually happened. I didn't see this before tracking it all the way up to the upstream routers and observing that they actually _did_ send out packets... /* Steinar */ -- Homepage: http://www.sesse.net/ -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists