* Re: [PATCH net-next v5 00/11] ipv6: Only create RTF_CACHE route after encountering pmtu exception [not found] ` <55BA1144.9090203@ahsoftware.de> @ 2015-08-15 7:48 ` Alexander Holler 2015-08-17 9:43 ` Alexander Holler 0 siblings, 1 reply; 6+ messages in thread From: Alexander Holler @ 2015-08-15 7:48 UTC (permalink / raw) To: Martin KaFai Lau, netdev Cc: David Miller, Hannes Frederic Sowa, Julian Anastasov, Steffen Klassert, Kernel Team, stable, linux-kernel Am 30.07.2015 um 13:57 schrieb Alexander Holler: > Am 29.07.2015 um 11:25 schrieb Alexander Holler: >> Am 23.05.2015 um 05:55 schrieb Martin KaFai Lau: >> >>> This series is to avoid creating a RTF_CACHE route whenever we are >>> consulting >>> the fib6 tree with a new destination. Instead, only create RTF_CACHE >>> route >>> when we see a pmtu exception. >> >> That even helps on systems without an IPv6-connection to world because >> it avoids the IPv6 route add/delete pairs which happened before whenever >> an IPv6-connection was tried (e.g. by Happy Eyeballs algorithms). >> >> I think that's worse a laud. thanks. > > Of course, I meant worth. Sorry, but the left part of my brain seems to > be sometimes in a (maybe forced) power save mode. ;) > > Also I wonder how the previous algorithm went into the kernel at all or > why it wasn't fixed earlier. Anyway, it's great that someone took the > time to fix that annoying behaviour (I've had on my radar since quiet > some time). To complete the discussion, that "annoying behaviour" is also a big information leak. Because routes aren't considered confidential and aren't subject to privacy, that broken behaviour enabled *everyone* on the same system to see *all* the remote IPv6 systems to which there have been connection establishment tries. E.g. I can see the following on a system when browsing to facebook.com and google.com: -------- [aholler@krabat snetmanmon.git]$ ./snetmanmon snetmanmon.conf.simple_example snetmanmon V1.3-5-g9f06 (C) 2015 Alexander Holler (...) New route 2a00:1450:4001:80c::100a (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' New route 2a03:2880:2130:cf05:face:b00c:0:1 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' New route 2a00:1450:4001:80c::1007 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' New route 2a00:1450:400f:803::101f (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' New route 2a00:1450:4001:80c::1008 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' New route 2a00:1450:4001:80c::1017 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' New route 2a00:1450:4016:804::200d (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' New route 2a00:1450:4001:80c::1000 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' New route 2a00:1450:4001:80c::1016 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' New route 2a00:1450:400f:803::1013 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' New route 2a00:1450:4001:80c::1006 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' New route 2a00:1450:4001:80c::1018 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' New route 2a00:1450:4016:804::2009 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' New route 2a00:1450:4001:80c::1005 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' Route 2a00:1450:4001:80c::100a (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted Route 2a03:2880:2130:cf05:face:b00c:0:1 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted Route 2a00:1450:4001:80c::1000 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted Route 2a00:1450:4001:80c::1005 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted Route 2a00:1450:4001:80c::1006 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted Route 2a00:1450:4001:80c::1007 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted Route 2a00:1450:4001:80c::1008 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted Route 2a00:1450:4001:80c::1016 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted Route 2a00:1450:4001:80c::1017 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted Route 2a00:1450:4001:80c::1018 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted Route 2a00:1450:400f:803::1013 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted Route 2a00:1450:400f:803::101f (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted Route 2a00:1450:4016:804::2009 (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted Route 2a00:1450:4016:804::200d (gateway fe80::21f:7bff:feb4:d13, type v6, scope universe) on interface 'virbr0' was deleted -------- (those deletes happen because I've no IPv6 connection to the outside world on that system) Also this doesn't give me the used URLs (or the user). it gives me quiet some good idea about what happens on a system. Therefor I think it's worse to think about backporting this patch series at least to the current long term stable kernel (4.1) too. Regards, Alexander Holler ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net-next v5 00/11] ipv6: Only create RTF_CACHE route after encountering pmtu exception 2015-08-15 7:48 ` [PATCH net-next v5 00/11] ipv6: Only create RTF_CACHE route after encountering pmtu exception Alexander Holler @ 2015-08-17 9:43 ` Alexander Holler 2015-08-28 7:36 ` Martin KaFai Lau 0 siblings, 1 reply; 6+ messages in thread From: Alexander Holler @ 2015-08-17 9:43 UTC (permalink / raw) To: Martin KaFai Lau, netdev Cc: David Miller, Hannes Frederic Sowa, Julian Anastasov, Steffen Klassert, Kernel Team, stable, linux-kernel Am 15.08.2015 um 09:48 schrieb Alexander Holler: > Am 30.07.2015 um 13:57 schrieb Alexander Holler: >> Am 29.07.2015 um 11:25 schrieb Alexander Holler: >>> Am 23.05.2015 um 05:55 schrieb Martin KaFai Lau: > To complete the discussion, that "annoying behaviour" is also a big > information leak. > > Because routes aren't considered confidential and aren't subject to > privacy, that broken behaviour enabled *everyone* on the same system to > see *all* the remote IPv6 systems to which there have been connection > establishment tries. Just in case I haven't described the problem I see clearly enough: "Everyone" means everything (other SW) too, and if "Happy_Eyeballs" algorithms are used (see RFC 6555), this also affects systems which only have an IPv4 connection to the world, as long as IPv6 is enabled. That means it does not only affect multiuser systems and the current behaviour of kernels < 4.2 renders e.g. the private mode of most browsers somewhat useless too (in regard to protection against other SW and/or users running on the same system). That's why I vote to check out if it's possible/reasonable to backport this series to the stable kernels. Regards, Alexander Holler ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net-next v5 00/11] ipv6: Only create RTF_CACHE route after encountering pmtu exception 2015-08-17 9:43 ` Alexander Holler @ 2015-08-28 7:36 ` Martin KaFai Lau 2015-08-28 9:27 ` Alexander Holler 2015-08-28 18:27 ` David Miller 0 siblings, 2 replies; 6+ messages in thread From: Martin KaFai Lau @ 2015-08-28 7:36 UTC (permalink / raw) To: Alexander Holler Cc: netdev, David Miller, Hannes Frederic Sowa, Julian Anastasov, Steffen Klassert, Kernel Team, stable, linux-kernel On Mon, Aug 17, 2015 at 11:43:20AM +0200, Alexander Holler wrote: > That's why I vote to check out if it's possible/reasonable to backport this > series to the stable kernels. I have backported to 4.0.y without major issue, so possible. I did try on 3.1x and gave up. It is a lot of changes, so I don't think it is a good idea for -stable. Thanks, Martin ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net-next v5 00/11] ipv6: Only create RTF_CACHE route after encountering pmtu exception 2015-08-28 7:36 ` Martin KaFai Lau @ 2015-08-28 9:27 ` Alexander Holler 2015-08-28 9:34 ` Alexander Holler 2015-08-28 18:27 ` David Miller 1 sibling, 1 reply; 6+ messages in thread From: Alexander Holler @ 2015-08-28 9:27 UTC (permalink / raw) To: Martin KaFai Lau Cc: netdev, David Miller, Hannes Frederic Sowa, Julian Anastasov, Steffen Klassert, Kernel Team, stable, linux-kernel Am 28.08.2015 um 09:36 schrieb Martin KaFai Lau: > On Mon, Aug 17, 2015 at 11:43:20AM +0200, Alexander Holler wrote: >> That's why I vote to check out if it's possible/reasonable to backport this >> series to the stable kernels. > I have backported to 4.0.y without major issue, so possible. Sure, as this was likely one of the versions they've used to create the patch. > I did try on 3.1x and gave up. > > It is a lot of changes, so I don't think it is a good idea for -stable. Depends on what you're expecting from a (stable) kernel. The patch description mentions what happens when a system deals with a lot of other ipv6-systems and that problem is easy to exercise and to value. Rating the information leak is harder, some people even won't understand that this might be a problem. And now look at which kernel-versions are now used in new devices (likely something <= 3.10, which is more than two years old), how long they will be used, and make a guess about IPv6 usage in 5 years. Anyway, I've no insights about all the politics happening in the background (e.g. stuff like the LTSI tree) and I've just wanted raise awareness about that (imho important) patch series. Regards, Alexander Holler ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net-next v5 00/11] ipv6: Only create RTF_CACHE route after encountering pmtu exception 2015-08-28 9:27 ` Alexander Holler @ 2015-08-28 9:34 ` Alexander Holler 0 siblings, 0 replies; 6+ messages in thread From: Alexander Holler @ 2015-08-28 9:34 UTC (permalink / raw) To: Martin KaFai Lau Cc: netdev, David Miller, Hannes Frederic Sowa, Julian Anastasov, Steffen Klassert, Kernel Team, stable, linux-kernel Am 28.08.2015 um 11:27 schrieb Alexander Holler: > Am 28.08.2015 um 09:36 schrieb Martin KaFai Lau: >> On Mon, Aug 17, 2015 at 11:43:20AM +0200, Alexander Holler wrote: >>> That's why I vote to check out if it's possible/reasonable to >>> backport this >>> series to the stable kernels. >> I have backported to 4.0.y without major issue, so possible. > > Sure, as this was likely one of the versions they've used to create the > patch. > >> I did try on 3.1x and gave up. >> >> It is a lot of changes, so I don't think it is a good idea for -stable. > > Depends on what you're expecting from a (stable) kernel. > > The patch description mentions what happens when a system deals with a > lot of other ipv6-systems and that problem is easy to exercise and to > value. > > Rating the information leak is harder, some people even won't understand > that this might be a problem. > > And now look at which kernel-versions are now used in new devices > (likely something <= 3.10, which is more than two years old), how long > they will be used, and make a guess about IPv6 usage in 5 years. > > Anyway, I've no insights about all the politics happening in the > background (e.g. stuff like the LTSI tree) and I've just wanted raise > awareness about that (imho important) patch series. Not to speak about phones, but those are most likely a problem of one specific company ;) Regards, Alexander Holler ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net-next v5 00/11] ipv6: Only create RTF_CACHE route after encountering pmtu exception 2015-08-28 7:36 ` Martin KaFai Lau 2015-08-28 9:27 ` Alexander Holler @ 2015-08-28 18:27 ` David Miller 1 sibling, 0 replies; 6+ messages in thread From: David Miller @ 2015-08-28 18:27 UTC (permalink / raw) To: kafai Cc: holler, netdev, hannes, ja, steffen.klassert, Kernel-team, stable, linux-kernel From: Martin KaFai Lau <kafai@fb.com> Date: Fri, 28 Aug 2015 00:36:38 -0700 > On Mon, Aug 17, 2015 at 11:43:20AM +0200, Alexander Holler wrote: >> That's why I vote to check out if it's possible/reasonable to backport this >> series to the stable kernels. > I have backported to 4.0.y without major issue, so possible. > > I did try on 3.1x and gave up. > > It is a lot of changes, so I don't think it is a good idea for -stable. I am absolutely, firmly, against any of this work going into -stable. It is completely inappropriate, the potential for regressions is enormous. ^ permalink raw reply [flat|nested] 6+ messages in thread
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2015-08-15 7:48 ` [PATCH net-next v5 00/11] ipv6: Only create RTF_CACHE route after encountering pmtu exception Alexander Holler
2015-08-17 9:43 ` Alexander Holler
2015-08-28 7:36 ` Martin KaFai Lau
2015-08-28 9:27 ` Alexander Holler
2015-08-28 9:34 ` Alexander Holler
2015-08-28 18:27 ` David Miller
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