[Bug 1849658] Re: resolved fallback to TCP fails for truncated UDP replies

[Launchpad Bug Tracker]

This bug was fixed in the package systemd - 242-7ubuntu3.2

---------------
systemd (242-7ubuntu3.2) eoan; urgency=medium

  [ Dan Streetman ]
  * d/extra/dhclient-enter-resolved-hook:
    - Replace use of bash-only &> with > and 2> (LP: #1849608)
  * d/p/lp1849658-resolved-set-stream-type-during-DnsStream-creation.patch:
    - Fix bug in refcounting TCP stream types (LP: #1849658)
  * d/extra/dhclient-enter-resolved-hook: cleanup temp $newstate file

  [ Rafael David Tinoco ]
  * Add support to KeepConfiguration= fixing behaviour for HA (LP: #1815101)
    - d/p/lp1815101-01-networkd-add-support-to-keep-configuration.patch
    - d/p/lp1815101-02-networkd-stop-clients-when-networkd-shuts-down.patch
    - d/p/lp1815101-03-network-add-KeepConfiguration-dhcp-on-stop.patch
    - d/p/lp1815101-04-network-make-KeepConfiguration-static-drop-DHCP-addr.patch
    - d/p/lp1815101-05-man-add-documentation-about-KeepConfiguration.patch

systemd (242-7ubuntu3.1) eoan; urgency=medium

  [ Balint Reczey ]
  * Fix shutdown and related actions from the login screen (LP: #1847896)
    File: debian/patches/logind-consider-greeter-sessions-suitable-as-display-sess.patch
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=b407dfd8c9dc81594553c27467c35b383333d74c
  * debian/gbp.conf: Set debian-branch to ubuntu-eoan
    File: debian/gbp.conf
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=f399ce2cf4701a2dbb4b3505d2dd17a210d62f5c

  [ Dan Streetman ]
  * Fix bogus routes after DHCP lease change (LP: #1831787)
    Files:
    - debian/patches/lp1831787/0001-networkd-Add-back-static-routes-after-DHCPv4-lease-e.patch
    - debian/patches/lp1831787/0002-network-set-preferred-source-in-removing-route-entry.patch
    - debian/patches/lp1831787/0003-network-lower-log-level-about-critical-connection.patch
    - debian/patches/lp1831787/0004-network-reset-Link-dhcp4_configured-flag-earlier.patch
    - debian/patches/lp1831787/0005-network-split-dhcp_lease_lost-into-small-pieces.patch
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=ced3f5c2f619083f7beb164d94d4ccfe52222fe8
  * Set src address for dhcp 'classless' routes (LP: #1835581)
    File: debian/patches/lp1835581-src-network-networkd-dhcp4.c-set-prefsrc-for-classle.patch
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=6a7ef370fb1335548448920be4ae6176b67044a8
  * Allows cache=no-negative option to be set, ignoring negative answers to
    be cached (LP: #1668771)
    File: debian/patches/lp1668771-resolved-switch-cache-option-to-a-tri-state-option-s.patch
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=27def26f5b1d1b8ba314c4a925fc1b7c43837f86

 -- Dan Streetman <ddstreet at canonical.com>  Fri, 01 Nov 2019 16:33:08
-0400

** Changed in: systemd (Ubuntu Eoan)
       Status: Fix Committed => Fix Released

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to systemd in Ubuntu.
https://bugs.launchpad.net/bugs/1849658

Title:
  resolved fallback to TCP fails for truncated UDP replies

Status in systemd package in Ubuntu:
  Fix Released
Status in systemd source package in Bionic:
  Fix Committed
Status in systemd source package in Disco:
  Fix Committed
Status in systemd source package in Eoan:
  Fix Released
Status in systemd source package in Focal:
  Fix Released

Bug description:
  [impact]

  for DNS UDP replies larger than 512 bytes, fallback to TCP is used.
  For example 'host toomany.ddstreet.org'.

  Due to a bug in resolved in refcounting DNS stream types, the refcount
  underflows for type 0 streams (which resolved uses to talk to upstream
  nameservers), resulting in resolved being unable to fallback to TCP to
  handle truncated UDP replies.

  [test case]

  ubuntu at sf247344-upstream:~$ dig +noanswer +noedns toomany.ddstreet.org
  ;; Truncated, retrying in TCP mode.

  ; <<>> DiG 9.11.3-1ubuntu1.9-Ubuntu <<>> +noanswer +noedns toomany.ddstreet.org
  ;; global options: +cmd
  ;; Got answer:
  ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2683
  ;; flags: qr rd ra; QUERY: 1, ANSWER: 40, AUTHORITY: 0, ADDITIONAL: 0

  ;; QUESTION SECTION:
  ;toomany.ddstreet.org.		IN	A

  ;; Query time: 0 msec
  ;; SERVER: 127.0.0.53#53(127.0.0.53)
  ;; WHEN: Thu Oct 24 11:40:29 UTC 2019
  ;; MSG SIZE  rcvd: 678

  ubuntu at sf247344-upstream:~$ sudo resolvectl flush-caches
  ubuntu at sf247344-upstream:~$ dig +noanswer +noedns toomany.ddstreet.org

  ; <<>> DiG 9.11.3-1ubuntu1.9-Ubuntu <<>> +noanswer +noedns toomany.ddstreet.org
  ;; global options: +cmd
  ;; connection timed out; no servers could be reached

  [regression potential]

  very low, as this only properly sets the stream type in the DnsStream
  object; any regression would be a failure to be able to use TCP for
  DNS requests or replies.

  [other info]

  https://github.com/systemd/systemd/pull/13838

  The commit adding stream types is not present in x/b, so this is
  needed only for disco and later.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1849658/+subscriptions