Date: Wed, 2 Oct 2019 15:51:25 -0700 From: =?UTF-8?B?56We5piO6YGU5ZOJ?= <jinmei@wide.ad.jp> To: Ryan Stone <rysto32@gmail.com> Cc: freebsd-net <freebsd-net@freebsd.org> Subject: Re: IPv6: Invalid nd6 entry created for an RA without an lladdr Message-ID: <CAJE_bqfk6f43aC32U26EHi6ETpqyWQyuS%2B32Ep8F5MwRgkjonA@mail.gmail.com> In-Reply-To: <CAFMmRNwntj7aKAPk1D-7%2BCvxRjtPTWX3J7qE0xkAbD=Y%2BdVbxw@mail.gmail.com> References: <CAFMmRNwntj7aKAPk1D-7%2BCvxRjtPTWX3J7qE0xkAbD=Y%2BdVbxw@mail.gmail.com>
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At Wed, 2 Oct 2019 17:04:23 -0400, Ryan Stone <rysto32@gmail.com> wrote: > > At work, our product is putting through an IPv6 conformance test and > it's found an issue in our handling of Routing Advertisements (RAs). > If we receive an RA that does not specify an lladdr, then > nd6_cache_lladdr() is called with lladdr NULL: > > https://svnweb.freebsd.org/base/head/sys/netinet6/nd6.c?revision=347984&view=markup#l1961 > > In this case, the linkhdr cache is never initialized, but we still put > the entry in the STALE state at line 2032. If lladdr is NULL shouldn't it reach line 2032? if (lladdr != NULL) { /* (7) */ nd6_llinfo_setstate(ln, ND6_LLINFO_STALE); EVENTHANDLER_INVOKE(lle_event, ln, LLENTRY_RESOLVED); } In any case, if a host receives an RA without a link-layer address option and no neighbor cache entry exists for the RA sender at that point, it shouldn't set the state of a newly created cache entry to STALE. While RFC4861 is not so explicit about this particular condition, I believe it's pretty clear from Section 6.3.4 of the RFC (it may even be questionable just to create an entry in this case, but that's probably within the scope of acceptable implementation choices as long as the entry is a mere placeholder). I also believe FreeBSD used to not do this (correctly), so if it currently sets it to STALE it's quite likely to be some regression. -- JINMEI, Tatuya
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