Date: Mon, 24 Sep 2018 15:15:18 -0400 From: "John W. O'Brien" <john@saltant.com> To: Don Lewis <truckman@FreeBSD.org> Cc: FreeBSD Net <freebsd-net@freebsd.org> Subject: Re: IPv6 fragment reassembly regression following FreeBSD-SA-18:10.ip Message-ID: <139c4032-b021-010d-a55d-7203e791ed15@saltant.com> In-Reply-To: <tkrat.a34a5d42cdde2a65@FreeBSD.org> References: <38a2d322-eae9-ec3d-284c-af29aed10c03@saltant.com> <tkrat.a34a5d42cdde2a65@FreeBSD.org>
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This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --Ln5JC2LZiTbvt8kZMAJ5T3LdAnDIM4MOy Content-Type: multipart/mixed; boundary="AAv3Hi0gPchy3mwEa0B9q22MsxLUrayuL"; protected-headers="v1" From: "John W. O'Brien" <john@saltant.com> To: Don Lewis <truckman@FreeBSD.org> Cc: FreeBSD Net <freebsd-net@freebsd.org> Message-ID: <139c4032-b021-010d-a55d-7203e791ed15@saltant.com> Subject: Re: IPv6 fragment reassembly regression following FreeBSD-SA-18:10.ip References: <38a2d322-eae9-ec3d-284c-af29aed10c03@saltant.com> <tkrat.a34a5d42cdde2a65@FreeBSD.org> In-Reply-To: <tkrat.a34a5d42cdde2a65@FreeBSD.org> --AAv3Hi0gPchy3mwEa0B9q22MsxLUrayuL Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 9/23/18 17:50, Don Lewis wrote: > On 23 Sep, John W. O'Brien wrote: >> I'd like to check my understanding and then ask a procedural question.= >> >> FreeBSD-SA-18:10.ip [0], released on 08/14, was resolved by r337828 [1= ]. >> That changeset, resulting in 11.1R-p13 and 11.2R-p2, included a patch = to >> the way IPv6 fragment reassembly is handled [2] that was part of the >> merge to releng. In an ensuing thread [3] two weeks later, an >> implementation defect was identified, but not before that defect had >> shipped. The defect is now being tracked as a bug [4], as of 09/03 has= >> been fixed in head and stable/11, and is registered as a blocker for 1= 2.0. >> >> I believe this defect is the cause of a problem I detected recently >> where postfix would query BIND on ::1 for the DNSSEC-signed AAAA of an= >> MX, and never receive a response. I'm a little puzzled that lo0 is >> affected in spite of having a 16k MTU, but the other signs are there: >> the symptoms appeared after upgrading from 11.2R-p1 to -p3, and I can >> perform that query successfully on UDPv4 or TCPv6. >> >> What I have been unable so far to determine is, will another 11.2R pat= ch >> be forthcoming to resolve this regression, and if so, when? I can limp= >> along without UDPv6 for a little while, but not until 11.3. The only >> clear alternative is to downgrade to -p1. >> >> [0] https://www.freebsd.org/security/advisories/FreeBSD-SA-18:10.ip.as= c >> [1] https://svnweb.freebsd.org/changeset/base/337828 >> [2] https://svnweb.freebsd.org/changeset/base/337776 >> [3] https://lists.freebsd.org/pipermail/svn-src-head/2018-August/11751= 4.html >> [4] https://bugs.freebsd.org/231045 >> >=20 > It looks to me like r337776 is a further performance improvement, only > present in head, which also introduced a new bug that was fixed by > r338406. I don't know why r338406 was merged to stable/11 since r337776= > was not. Stable/11 only has the original fix (r337787 in head, r337803= > in stable/11). Hi Don, I'm looking at this line of code [5] in releng/11.2. It looks to me like that's what r338406 fixed in head [6]. Am I being obtuse here? [5] https://svnweb.freebsd.org/base/releng/11.2/sys/netinet6/frag6.c?annotate= =3D337828#l219 [6] https://svnweb.freebsd.org/base/head/sys/netinet6/frag6.c?r1=3D338406&r2=3D= 338405&pathrev=3D338406 --=20 John W. O'Brien OpenPGP keys: 0x33C4D64B895DBF3B --AAv3Hi0gPchy3mwEa0B9q22MsxLUrayuL-- --Ln5JC2LZiTbvt8kZMAJ5T3LdAnDIM4MOy Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEKpEHkkRoSDiIJkQOWPtK56pP/m4FAlupN8oACgkQWPtK56pP /m7q5Qf/caqMuYucFZYyT/D+yo9P9UjNX84JfmoTdt4z38TZEnOhJwePYmxkamhr OlsAjuhLyDUdbfw0cMCqs/rpSwoeRPgBd2+6LClzr70N1PjuA4l6ynA/XgEK2vZp F9E6fkX6THDHI026qmbAqKLb2NHwqjdrD2vTDemDHKTeY5AGw0vPV6+U7D4OPykv eniV8lyoR0DM+AlbhaA0MOLOIGyimVtG5cGh6RArCuzfTMPW2D3i0WlK0WfmWX2s MRdBQ89+NlvpUeQC7jGc/qvhpguEq6TvlODmw9iLX32XPEZnXJEwfrpTP2k676Wg +jkdm27bt0BNh9itq9pFSPWOLoOQZw== =vbG/ -----END PGP SIGNATURE----- --Ln5JC2LZiTbvt8kZMAJ5T3LdAnDIM4MOy--
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