On 21.05.2016 17:19, Tom Herbert wrote: > On Sat, May 21, 2016 at 2:34 AM, Hannes Frederic Sowa > <han...@stressinduktion.org> wrote: >> On Sat, May 21, 2016, at 03:56, Sowmini Varadhan wrote: >>> On (05/21/16 02:20), Hannes Frederic Sowa wrote: >>>> >>>> There are some options inherently protocol depending like the jumbo >>>> payload option, which should be under control of the kernel, or the >>>> router alert option for igmp, which causes packets to be steered towards >>>> the slow/software path of routers, which can be used for DoS attacks. >>>> >>>> Setting CALIPSO options in IPv6 on packets as users would defeat the >>>> whole CALIPSO model, etc. >>>> >>>> The RFC3542 requires at least some of the options in dst/hop-by-hop >>> >>> "requires" is a strong word. 3542 declares it as a "may" (lower case). >>> The only thing required strongly is IPV6_NEXTHOP itself. >>> >>> I suspect 3542 was written at a time when hbh and dst opt were loosely >>> defined and the "may" is just a place-holder (i.e., it's not even a MAY) >> >> My wording directly from the RFC was too strong, true, but given that >> there is a CALIPSO patch already floating around for the kernel and >> those options are strictly controlled by selinux policy and build the >> foundation for the networking separation we can't make it simply >> non-priv. >> > If you don't mind I'll change this to make specific options are > privileged and not all hbh and destopt. There is talk in IETF about > reinventing IP extensibility within UDP since the kernel APIs don't > allow setting EH. I would like to avoid that :-)
Hehe, certainly. A white list of certain registered IPv6 IANA-options for non-priv whould certainly fly in my opinion. That is what I meant with "More fine-grained parsing and setting of those options has never been implemented." from my first mail. I am not that certain about a blacklist though, but haven't thought about that enough. I didn't yet get around to review other options, but basically people could use private options in some proprietary settings and we could break their assumptions by such a change. Would a white list be sufficient? Bye, Hannes
