Newsletters: add #14 (2018-09-25)

Author: harding

_includes/references.md

@@ -21,6 +21,11 @@
 [BIP158]: https://github.com/bitcoin/bips/blob/master/bip-0158.mediawiki
 [BIP174]: https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki
 
+{% comment %}<!-- BOLTs in order lowest to highest -->{% endcomment %}
+[BOLT2]: https://github.com/lightningnetwork/lightning-rfc/blob/master/02-peer-protocol.md
+[BOLT7]: https://github.com/lightningnetwork/lightning-rfc/blob/master/07-routing-gossip.md
+[BOLT11]: https://github.com/lightningnetwork/lightning-rfc/blob/master/11-payment-encoding.md
+
 {% comment %}<!-- old newsletters (variables & links) in date order earliest to latest -->{% endcomment %}
 {% assign news0 = "/en/newsletters/2018/06/08/" %}
 [newsletter #0]: {{news0}}

_posts/en/newsletters/2018-09-25-newsletter.md

@@ -0,0 +1,204 @@
+---
+title: 'Bitcoin Optech Newsletter #14'
+permalink: /en/newsletters/2018/09/25/
+name: 2018-09-25-newsletter
+type: newsletter
+layout: newsletter
+lang: en
+---
+This week's newsletter includes action items and news related to last week's
+security release of Bitcoin Core 0.16.3 and Bitcoin Core 0.17RC4, popular
+questions and answers from the Bitcoin StackExchange over the past
+month, and short descriptions of notable merges made to popular Bitcoin
+infrastructure projects.
+
+- **Upgrade to Bitcoin Core 0.16.3 to fix CVE-2018-17144:** as widely
+  reported early Friday (UTC), the denial-of-service vulnerability
+  described in last week's Optech newsletter is now known to allow
+  miners to trick affected systems into accepting invalid bitcoins.
+  
+    As of this writing, it's believed that a majority of large Bitcoin
+    services and miners have upgraded, likely ensuring that any blocks
+    exploiting the bug will be quickly reorganized out of the most
+    proof-of-work chain---reducing the risk for SPV clients and
+    non-upgraded nodes.
+  
+    If you don't plan to upgrade or if you use an SPV client, you should
+    consider waiting for more confirmations than you usually do (30
+    confirmations---about 5 hours worth---is a normal
+    [recommendation][reorg risk recommendation] in these sort of
+    situations, as that's enough time for people to notice a problem and
+    get warnings published).  Otherwise, upgrading to one of the
+    following versions remains highly recommended for any system,
+    especially those systems handling money:
+
+    - [0.16.3][] (current stable)
+
+    - [0.17.0RC4][bcc 0.17] (release candidate for next major version)
+
+    - [0.15.2][] (backport to old version, may have other issues)
+
+    - [0.14.3][] (backport to old version, may have other issues)
+  
+- **Allocate time to test Bitcoin Core 0.17RC4:** Bitcoin Core has
+  uploaded [binaries][bcc 0.17] for 0.17 Release Candidate (RC) 4.
+  Testing is greatly appreciated and can help ensure the quality of the
+  final release.
+
+## News
+
+- **CVE-2018-17144:** the initial and subsequent disclosures of
+  information about this bug were the only significant news this week.
+  For more information, we suggest reading the following sources:
+
+    - [Bitcoin Core full disclosure][]
+
+    - [Original confidential report][], now public
+
+    - [Additional technical information][bse 79484] by Andrew Chow (also described below)
+
+    - [CVE-2018-17144][], National Vulnerability Database (NVE) entry
+      being updated by Luke Dashjr
+
+    We're aware of several very insightful people currently reflecting
+    upon the bug, its ultimate causes, and possible methods for reducing
+    the risk of future serious bugs.  An especially good venue for
+    Bitcoin Core internal discussion will be during the October 8th
+    though 10th [CoreDev.tech][] meetings following the Tokyo Scaling
+    Bitcoin conference.  We plan to follow up with links to any
+    significant conclusions that are published.
+
+    Optech thanks the original reporter, Awemany, for his responsible
+    disclosure as well as the following developers who unhesitatingly
+    made the time to quickly confirm the issue, address it, and quietly
+    provide round-the-clock monitoring for attempts to exploit the
+    then-undisclosed inflation risk: Pieter Wuille, Gregory Maxwell,
+    Wladimir van der Laan, Cory Fields, Suhas Daftuar, Alex Morcos, and
+    Matt Corallo.
+    
+## Selected Q&A from Bitcoin StackExchange
+
+{% comment %}<!-- https://bitcoin.stackexchange.com/search?tab=votes&q=created%3a1m..%20is%3aanswer -->{% endcomment %}
+
+*[Bitcoin StackExchange][bitcoin.se] is one of the first places Optech
+contributors look for answers to their questions---or when we have a
+few spare moments of time to help answer other people's questions.  In
+this monthly feature, we highlight some of the top voted questions and
+answers made since our last update.*
+
+- [How does CVE-2018-17144 work?][bse 79484] Andrew Chow provides a
+  detailed explanation of how Bitcoin Core can be crashed or tricked
+  into accepting multiple spends of the same input in versions
+  vulnerable to this bug.
+
+- [Why doesn't Bitcoin use UDP instead of TCP?][bse 79175] Gregory
+  Maxwell describes a case where important Bitcoin software does already
+  use UDP and then details the reasons why UDP support isn't implemented
+  in popular full node software.  He concludes with a description of
+  some potential benefits that might be available if UDP support was
+  implemented.
+
+- [How likely are you to get blacklisted by an exchange if you use
+  Wasabi wallet's CoinJoin mixing?][bse 78654] Wasabi Wallet author
+  Adam Ficsor explains that nothing stops exchanges from refusing funds
+  mixed through Wasabi, but that several features of Wasabi (such as a
+  required anonymity set of 100) can help make blocking users bad for
+  business.  Alternatively, he links to a tool that may allow users to
+  circumvent an address blacklist.
+
+- [What's the minimum number for a Bitcoin private key?][bse 79472]
+  Answers from Mark Erhardt and Gregory Maxwell were provided within a
+  minute of each other, but a humorous rephrasing of Maxwell's answer by
+  Nate Eldredge has more upvotes than either answer as of this writing.
+
+## Notable commits
+
+*Notable commits this week in [Bitcoin Core][core commits], [LND][lnd
+commits], and [C-lightning][cl commits].  Reminder: new merges to
+Bitcoin Core are made to its master development branch and are unlikely
+to become part of the upcoming 0.17 release---you'll probably have to
+wait until version 0.18 in about six months from now.*
+
+{% include linkers/github-log.md 
+  refname="core commits"
+  repo="bitcoin/bitcoin"
+  start="c53e083a49291b611d278a8db24ff235c1202e43"
+  end="920c090f63f4990bf0f3b3d1a6d3d8a8bcd14ba0"
+%}
+{% include linkers/github-log.md 
+  refname="lnd commits"
+  repo="lightningnetwork/lnd"
+  start="3b2c807288b1b7f40d609533c1e96a510ac5fa6d"
+  end="f4305097e1638f6f8958dfa9eec941d8bf80246e"
+%}
+{% include linkers/github-log.md 
+  refname="cl commits"
+  repo="ElementsProject/lightning"
+  start="36eab5de26e203311ceeb65c94ec5beb9c94ff5d"
+  end="3ce53ab9eddd397d57b6afc5faefe6703e56ac26"
+%}
+
+- [Bitcoin Core #13152][]: when connected to the peer-to-peer network,
+  nodes share the IP addresses of other nodes they've heard about and
+  these addresses are stored in a database that Bitcoin Core queries
+  when it wants to open a new connection.  This PR adds a new RPC command,
+  `getnodeaddresses`, that returns one or more of these addresses.  This
+  can be useful in conjunction with tools like [bitcoin-submittx][].
+
+- [LND #1738][]: the logic for validating channel updates has been
+  moved to the routing package so that it's available both in routing
+  (to handle failed payment sessions) and the gossiper (where it was
+  handled before).  This fixes issue [#1707][LND #1707] (and implements
+  a test case for it) that may have allowed a node to trick one of its
+  peers into believing a different peer had a routing failure, thus
+  possibly redirecting traffic to the malicious node.
+  
+- C-Lightning now provides a `gossipwith` tool that allows you to
+  receive gossip from a node independently of lightningd or even to send
+  the remote node a message.  This tool is used for additional testing
+  of lightningd's gossip component.
+
+- C-Lightning now complies with updates to [BOLT7][bolt7] by
+  splitting the previous `flags` field for the `listchannels` RPC into
+  two new fields: `message_flags` and `channel_flags`.  Also code
+  comments and references to [BOLT2][] and [BOLT11][] have been updated.
+
+- C-Lightning has significantly expanded the in-code documentation of
+  its secrets module.  The documentation is remarkably good (and, at
+  times, quite humorous).  See [hsmd.c][].  The code comments even
+  document other code comments:
+
+    ```c
+    /*~ You'll find FIXMEs like this scattered through the code.
+     * Sometimes they suggest simple improvements which someone like
+     * yourself should go ahead an implement.  Sometimes they're deceptive
+     * quagmires which will cause you nothing but grief.  You decide! */
+
+     /* FIXME: We should cache these. */
+     get_channel_seed(&c->id, c->dbid, &channel_seed);
+     derive_funding_key(&channel_seed, &funding_pubkey, &funding_privkey);
+    ```
+
+- C-Lightning can now make multiple requests in parallel to bitcoind,
+  speeding up operations on slow systems or on nodes performing long-running
+  operations.
+
+{% include references.md %}
+{% include linkers/issues.md issues="13152,1738,1707" %}
+
+{% assign bse = "https://bitcoin.stackexchange.com/a/" %}
+[bse 79484]: {{bse}}79484
+[bse 79175]: {{bse}}79175
+[bse 78654]: {{bse}}78654
+[bse 79472]: {{bse}}79472
+[0.16.3]: https://bitcoincore.org/en/2018/09/18/release-0.16.3/
+[0.15.2]: https://github.com/bitcoin/bitcoin/releases/tag/v0.15.2
+[0.14.3]: https://github.com/bitcoin/bitcoin/releases/tag/v0.14.3
+[reorg risk recommendation]: https://btcinformation.org/en/you-need-to-know#instant
+[bitcoin core full disclosure]: https://bitcoincore.org/en/2018/09/20/notice/
+[original confidential report]: https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-September/016424.html
+[cve-2018-17144]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-17144
+[bcc 0.17]: https://bitcoincore.org/bin/bitcoin-core-0.17.0/
+[coredev.tech]: https://coredev.tech/
+[hsmd.c]: https://github.com/ElementsProject/lightning/blob/master/hsmd/hsmd.c
+[bitcoin-submittx]: https://github.com/laanwj/bitcoin-submittx