touch-packages team mailing list archive

[Björn Lindqvist <bjourne@xxxxxxxxx>]

The bug is present still in Ubuntu Trusty.

** Also affects: eglibc via
   http://sourceware.org/bugzilla/show_bug.cgi?id=14969
   Importance: Unknown
       Status: Unknown

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https://bugs.launchpad.net/bugs/582585

Title:
  getaddrinfo() returns duplicate addresses under AI_ADDRCONFIG

Status in eglibc:
  Unknown
Status in eglibc package in Ubuntu:
  Confirmed

Bug description:
  Presume I have a computer that has no global IPv6 addresses, but a few
  IPv4 addresses.

  Applications using getaddrinfo() with hints.ai_flags = AI_ADDRCONFIG
  set will properly omit IPv6 addresses, HOWEVER they will return
  duplicate IPv4 addresses.

  Demonstration code attached.

  Without IPv6 addresses:

  # show setup
  $ grep -w localhost /etc/hosts
  127.0.0.1	localhost
  ::1     localhost ip6-localhost ip6-loopback
  $ ip a s | grep inet
      inet 127.0.0.1/8 scope host lo
      inet6 ::1/128 scope host 
      inet 192.168.0.4/24 brd 192.168.0.255 scope global eth0
      inet6 fe80::226:XXXX:XXXX:XXXX/64 scope link  # masked for privacy

  # compile test case
  $ gcc -Wall -Wextra -pedantic -O -o libcbug-demo libcbug-demo.c

  # run test case
  $ ./libcbug-demo localhost echo
  Address 1: 127.0.0.1
  Address 2: 127.0.0.1

  (127.0.0.1 should be listed only once, Solaris 10 for instance
  achieves that)

  Now configure a fake IPv6 address (don't do this on hosts with real
  IPv6 connectivity, it suffices to use your real IPv6 address) and re-
  run the application:

  $ ip a a 2001::2001 dev eth0 # set up IPv6
  $ ./libcbug-demo localhost echo
  Address 1: ::1
  Address 2: 127.0.0.1
  $ ip a d 2001::2001 dev eth0 # deconfigure bogus address

  (This is fine)

  Practical consequence: excessive connection retries by applications
  that possibly take a long time.

  This isn't Ubuntu specific.

  ProblemType: Bug
  DistroRelease: Ubuntu 10.04
  Package: libc6 2.11.1-0ubuntu7
  ProcVersionSignature: Ubuntu 2.6.32-22.33-generic 2.6.32.11+drm33.2
  Uname: Linux 2.6.32-22-generic x86_64
  NonfreeKernelModules: fglrx
  Architecture: amd64
  Date: Wed May 19 01:13:51 2010
  ProcEnviron:
   PATH=(custom, no user)
   LANG=de_DE.UTF-8
   SHELL=/bin/bash
  SourcePackage: eglibc

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