libc6-udeb resolver segfaults when resolving local addresses with no domain

[Paul Nijjar]

I do not know whether this bug belongs to debian-installer, anna or libc6-udeb, so I will follow Launchpad's suggestion.

I install machines using preseeding, with a local apt-cacher-ng proxy called "apt-cache". In this case I am installing Ubuntu 14.04 . I install both on i386 and amd64 architectures, and am getting the same results.

When installing I get the message that the installer failed to download a file from the mirror, during the bootstrap installer download. It always fails at the same point: when downloading libcryptsetup4-udeb, immediately after downloading libc6-udeb_2.19-0ubuntu6.7_amd64.udeb.

Switching to one of the consoles, I find that name resolutions are failing for addresses on my local network when I do not specify a fully-qualified domain name, but succeeding for addresses where the domain is specified. Here is an example:

~ # ping apt-cache
Segmentation fault
~ # ping apt-cache.theworkingcentre.org
PING apt-cache.theworkingcentre.org (10.11.12.26): 56 data bytes

In syslog I see the following suspicious entries:

Feb 25 05:46:45 anna[3577]: DEBUG: retrieving jfsutils-udeb 1.1.15-2.1
Feb 25 05:46:45 anna[3577]: 2016-02-25 05:46:45 URL:http://apt-cache:3142/ca.archi
ve.ubuntu.com/ubuntu/pool/main/j/jfsutils/jfsutils-udeb_1.1.15-2.1_amd64.udeb [162
150/162150] -> "/var/cache/anna/jfsutils-udeb_1.1.15-2.1_amd64.udeb" [1]
Feb 25 05:46:45 anna[3577]: DEBUG: retrieving libbsd0-udeb 0.6.0-2ubuntu1
Feb 25 05:46:45 anna[3577]: 2016-02-25 05:46:45 URL:http://apt-cache:3142/ca.archi
ve.ubuntu.com/ubuntu/pool/main/libb/libbsd/libbsd0-udeb_0.6.0-2ubuntu1_amd64.udeb
[24916/24916] -> "/var/cache/anna/libbsd0-udeb_0.6.0-2ubuntu1_amd64.udeb" [1]
Feb 25 05:46:45 anna[3577]: DEBUG: retrieving libc6-udeb 2.19-0ubuntu6.7
Feb 25 05:46:46 anna[3577]: 2016-02-25 05:46:46 URL:http://apt-cache:3142/ca.archi
ve.ubuntu.com/ubuntu/pool/main/e/eglibc/libc6-udeb_2.19-0ubuntu6.7_amd64.udeb [111
8088/1118088] -> "/var/cache/anna/libc6-udeb_2.19-0ubuntu6.7_amd64.udeb" [1]
Feb 25 05:46:47 anna[3577]: DEBUG: retrieving libcryptsetup4-udeb 2:1.6.1-1ubuntu1
Feb 25 05:46:47 anna[3577]: Segmentation fault
Feb 25 05:46:47 kernel: [ 45.546051] wget[4856]: segfault at 14 ip 00007fe0079d5
d66 sp 00007fffb3a959a0 error 6 in libresolv-2.19.so[7fe0079ca000+17000]
Feb 25 05:46:47 anna[3577]: Segmentation fault

The "libresolv-2.19.so" makes me think that this problem might have something to do with the security update to glibc, but I have no proof of this.

I do know that the installers worked before. If I change my preseed entries for the local cache to fully-qualified domain names then the installer works. If I specify an IP address for the apt-cacher-ng machine then the installer works.

This happens consistently for me, on several different pieces of hardware.

I will attach my syslog and dmesg output. If there are other files I should include, or there is a more effective way to run apport or ubuntu-bug or something this early in the install process, let me know.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Paul Nijjar (paul-nijjar)]

I am pretty sure this is a duplicate of #1546459 . Downloading a new netinstall from trusty-updates (not trusty) seems to fix the problem. In particular I used the following:

open http://ca.archive.ubuntu.com/ubuntu/dists/trusty-updates/main/installer-amd64/current/images/netboot/ubuntu-installer/

I had not realized that there was a new version of the installer because I was looking in the wrong directory.